Neurosteroid regulation of GABAA receptor single-channel kinetic properties of mouse spinal cord neurons in culture. 1. Single-channel kinetics of steroid enhancement of single gamma-aminobutyric acidA (GABA) receptor currents obtained from somata of mouse spinal cord neurones in culture were investigated using the excised outside-out patch-clamp recording technique. GABA (2 microM) and GABA (2 microM) plus androsterone (5 alpha-androstan-3 alpha-ol-17-one, AND, 10 nM-10 microM) or pregnanolone (5 beta-pregnan-3 alpha-ol-20-one, PRE, 100 nM-10 microM) applied by pressure ejection from micropipettes evoked inward currents when patches were voltage clamped at -75 mV in symmetrical chloride solutions. Averaged GABA receptor currents were increased in the presence of the steroids. 2. GABA receptor currents were recorded with at least two conductance levels, a predominant or main-conductance level of about 28 pS (which contributed 96% of the current evoked) and a minor or sub-conductance level of about 20 pS. The current amplitudes of the two conductance levels were unchanged by the steroids. The gating (opening and closing) kinetics of both of the conductance levels were analysed. Findings for the main-conductance level are summarized below. 3. Both steroids increased the average GABA receptor channel open duration. Consistent with the increased GABA receptor channel average open duration, the steroids shifted frequency histograms of GABA receptor channel open durations to longer durations. Three exponential functions were required to fit best the frequency histograms of GABA open durations, consistent with at least three kinetic open states of the main-conductance level. Time constants obtained from the GABA receptor channel open-duration frequency histograms were unchanged in the presence of the steroids. The basis for the increased average GABA receptor channel open durations by the steroids was due to an increased relative proportion of the two longer open-duration time constants. The GABA receptor channel average open durations were increased by AND and PRE in a concentration-dependent manner by shifting the proportion of openings to the longer open time constants. At a concentration of 10 microM, the prolongation of the average open duration was decreased, suggesting that the GABA receptor channel was blocked by these steroids. 4. GABA receptor channel opening frequency was increased and average channel-closed duration was decreased by AND or PRE. Consistent with this, areas of the frequency histograms of channel closed durations were shifted to shorter durations. Closed frequency distributions were fitted best with five to six exponential functions, suggesting that the channel had multiple kinetic closed states. The three briefest time constants were not greatly altered by the steroids.(ABSTRACT TRUNCATED AT 400 WORDS)


Macroscopic and unitary properties of physiological ion flux through T-type Ca2+ channels in guinea-pig heart cells. 1. We sought to distinguish two types of Ca2+ channel in guinea-pig ventricular cells (T-type and L-type) and to characterize their respective gating and permeation properties when Ca2+ (1-10 mM) is the charge carrier, as is the case physiologically. 2. Na+ was removed from both the external and internal solutions to eliminate currents through Na+ channels and Na(+)-Ca2+ exchange. Major differences in the voltage dependence of steady-state inactivation were exploited to separate the two Ca2+ current components. 3. From a holding potential of -50 mV, only L-type channels were available to open with depolarization. When holding at -90 mV, T-type channels contributed an additional rapidly inactivating component superimposed upon the L-type current. Only the L-type channels thus identified were sensitive to the dihydropyridine Ca2+ channel blocker nitrendipine. 4. T-type currents, measured by taking the difference between the currents elicited from a holding potential of -90 mV and those elicited from -50 mV, peaked within 10 ms and decayed completely within 50-100 ms. 5. Macroscopic T-type currents were largest during depolarizing pulses between -40 and -30 mV (peak current density of 0.62 +/- 0.21 nA nF-1) and decreased at more positive potentials, becoming unmeasurably small above 0 mV. 6. Unitary currents recorded with similar ionic conditions and voltage protocols exhibited a single-channel conductance of 4-5 pS in 10 mM Ca2+. Ensemble average currents through a single channel reproduced accurately the time course of whole-cell T-type current. Permeation properties could not explain the absence of macroscopic T-type currents at positive test potentials, which must therefore be attributable to gating. 7. Convolution analysis was employed to clarify the single-channel basis of the rapidly decaying current waveform of T-type channels. The latencies to first opening and reopening, which reflect activation and deactivation, influenced the waveform most strikingly. Open times were sufficiently brief that they contributed little to shaping the average current. Thus, macroscopic inactivation largely reflects rate-limiting activation events. 8. The unitary current amplitudes and peak open probabilities measured for single T-type channels, when compared to the average macroscopic T-type current density, predict 10.6 functional channels per picofarad, or approximately 1700 T-type channels per typical ventricular myocyte.


Macroscopic and unitary properties of physiological ion flux through L-type Ca2+ channels in guinea-pig heart cells. 1. We investigated the currents through L-type Ca2+ channels when Ca2+ (1-10 mM) was the charge carrier, as is the case physiologically. 2. Na+ was removed from both the external and internal solutions to eliminate currents through Na+ channels and Na(+)-Ca2+ exchange. 3. From a holding potential of -50 mV only L-type channels were available to open with depolarization. Macroscopic L-type currents were maximal during depolarizing pulses to +10 mV (peak current density of 4.7 +/- 0.3 nA nF-1). 4. During depolarizing steps as long as 180 ms, the decay of current through L-type channels was incomplete, in contrast to that of T-type current. 5. Unitary currents recorded with comparable ionic conditions and voltage protocols exhibited a single-channel conductance of 6.9 pS in 10 mM Ca2+. Ensemble average currents reproduced accurately the features of whole-cell L-type current, including the maintained component. 6. Convolution analysis was employed to clarify the single-channel basis of the complex current waveform of L-type channels. First openings underlie the peak, while the maintained pedestal is generated by multiple re-openings. As with T-type channels, single openings are brief and contribute little to the time course of the average current. 7. The prominent maintained component of macroscopic and ensemble average L-type current cannot be explained by simple Markov models in which current decay reflects the progressive entry of channels into an absorbing inactivated state. 8. We considered the possibility that the maintained component of current arises from the existence of multiple distinct gating patterns, one of which lacks inactivation. Individual sweeps were sorted among three patterns of gating (no openings, active-early and active-late). Patterns of activity are not randomly distributed; instead, they tend to cluster over time. 9. Most of the maintained current is attributable to the 'active-late' pattern of gating. Considered separately, this pattern can be well described by a simple Markov chain lacking an inactivated state. The 'active-early' gating pattern accounts entirely for the initial current transient, and for about one-third of the maintained component; thus, inactivation, even when present, must be reversible rather than absorbing. 10. The unitary current amplitudes and peak open probabilities measured for single L-type channels, when compared to the average macroscopic L-type current density, predict 170 functional channels per picofarad, or 28,000 L-type channels per typical ventricular myocyte.(ABSTRACT TRUNCATED AT 400 WORDS)


Membrane conductances involved in amplification of small signals by sodium channels in photoreceptors of drone honey bee. 1. Voltage signals of about 1 mV evoked in photoreceptors of the drone honey bee by shallow modulation of a background illumination of an intensity useful for behaviour are thought to be amplified by voltage-dependent Na+ channels. To elucidate the roles of the various membrane conductances in this amplification we have studied the effects of the Na+ channel blocker tetrodotoxin (TTX) and various putative K+ channel blockers on the membrane potential, Vm. 2. Superfusion of a slice of retina with 0.5-10 mM-4-aminopyridine (4-AP) depolarized the membrane and, in fifty of sixty-three cells induced repetitive action potentials. Ionophoretic injection of tetraethylammonium produced similar effects. 3. In order to measure the depolarization caused by 4-AP, action potentials were prevented by application of TTX: 4-AP was applied when the membrane was depolarized to different levels by light. 4-AP induced an additional depolarization at all membrane potentials tested (-64 to -27 mV). We conclude that there are 4-AP-sensitive K+ channels that are open at constant voltage over this range. 4. 4-AP slowed down the recovery phase of the action potential induced by a light flash by a factor that ranged from 0.51 to 0.16. This reduction could be accounted for by the reduction in a voltage-independent K+ conductance estimated from the steady-state depolarization. 5. After the voltage-gated Na+ channels had been blocked by TTX, exposure to 4-AP further changed the amplitude of the response to a small (approximately 10%) decremental light stimulus. The change was an increase when the background illumination brought Vm to potentials more negative than about -40 mV; it was a decrease when Vm > -40 mV. The data could be fitted by a circuit representation of the membrane with a light-activated conductance and a K+ conductance (EK = -66 mV) that was partly blocked by 4-AP. The voltage range studied was from -52 to -27 mV; neither conductance in the model was voltage dependent. 6. The responses to small changes in light intensity in the absence of TTX were mimicked by a model. We conclude that a voltage-dependent Na+ conductance described by the Hodgkin-Huxley equations can amplify small voltage changes in a cell membrane that is also capable of generating action potentials; the magnitude of the K+ conductance is critical for optimization of signals while avoiding membrane instability.


The regulation of disynaptic reciprocal Ia inhibition during co-contraction of antagonistic muscles in man. 1. The disynaptic reciprocal inhibition from ankle dorsiflexors to ankle plantarflexors was investigated at rest, during tonic plantar- and dorsiflexion and during co-contraction. In relation to rest, it was found to be decreased during plantarflexion and co-contraction, but unchanged during dorsiflexion. 2. When increasing the strength of plantarflexion the amount of inhibition became progressively smaller. Already during weak co-contraction, the amount of inhibition was very small and it did not become smaller during stronger contraction. The decrease of inhibition during co-contraction could not be explained by an addition of the changes of inhibition observed during plantar- and dorsiflexion individually. 3. The disynaptic reciprocal inhibition was also found to be decreased when the peripheral feedback from the muscles was blocked by inducing ischaemia in the leg and at the beginning of a dynamic co-contraction before sensory feedback could interfere. This implies that the observed decrease is caused by a central inhibition of the transmission in the pathway. 4. The amount of disynaptic reciprocal inhibition was also investigated during standing. No significant difference in the amount of inhibition was found when the subjects were standing up at rest as compared to sitting down at rest. When the subjects were forced to make a co-contraction in order to maintain balance, i.e. when they were standing on one leg, leaning backwards or standing on an unstable platform, a decrease of disynaptic reciprocal inhibition was seen. When the subjects leaned forward, thus forcing a contraction of the soleus muscle, a decrease was also seen, but it was smaller than in the co-contraction tasks. Finally, when the subjects lifted the examined leg, thus contracting the tibialis anterior muscle, either no change or a small increase of inhibition was seen. 5. A similar control of the disynaptic reciprocal inhibition as described for the pathway from ankle dorsiflexors to ankle plantarflexors was also observed for the pathway from ankle plantarflexors to dorsiflexors and from wrist extensors to wrist flexors. 6. It is concluded that when co-contraction is used in order to stabilize a joint, i.e. to maintain posture, a specific co-contraction motor programme is activated that depresses the transmission in the disynaptic reciprocal pathway thereby ensuring a high excitability level in the motoneurones of both antagonistic muscles.


Voltage-dependent sodium and calcium currents in cultured parasympathetic neurones from rat intracardiac ganglia. 1. Depolarization-activated Na+ and Ca2+ currents underlying the rising phase of the action potential in mammalian parasympathetic ganglion cells were investigated in voltage-clamped neurones dissociated from neonatal rat intracardiac ganglia and maintained in tissue culture. 2. A current component isolated by replacing intracellular K+ with Cs+ or arginine and adding 0.1 mM Cd2+ to the external solution was dependent on extracellular [Na+] and reversibly blocked in the presence of 300 nM tetrodotoxin (TTX). Peak amplitudes of Na+ currents elicited by step depolarization from a holding potential of -100 mV were 351 +/- 18 pA/pF (140 mM extracellular Na+). 3. The sodium current-voltage (I-V) curve exhibited a threshold for activation at -40 mV and reached a maximum at -10 mV. The Na+ conductance increased sigmoidally with increasing depolarization reaching half-maximal activation at -25 mV, with a maximum slope corresponding to 7.5 mV per e-fold change in conductance. 4. During a maintained depolarization, Na+ currents turned on and then decayed (inactivated) with an exponential time course. The time constant of inactivation was voltage dependent decreasing from 0.85 ms at -20 mV to 0.3 ms at +60 mV (23 degrees C). The steady-state inactivation of the Na+ conductance was voltage-dependent with half-inactivation occurring at -61 mV and near-complete inactivation at -20 mV. Recovery from inactivation also followed an exponential time course with a time constant that increased at depolarized membrane potentials. 5. A voltage- and Ca(2+)-dependent current was isolated by replacement of intracellular K+ with either Cs+ or arginine and of extracellular Na+ with tetraethylammonium and the addition of TTX. Extracellular Ba2+ or Na+ (in the absence of external divalent cation) could substitute for Ca2+. Peak Ca2+ current increased with increasing extracellular [Ca2+] and above 10 mM (Kd approximately 4 mM) approached saturation. The peak Ca2+ current density was 45 +/- 4 pA/pF (2.5 mM-extracellular Ca2+). 6. The Ca2+ I-V relation exhibited a high threshold for activation (-20 mV) and reached a maximum at +20 mV. Changing the holding potential from -100 to -40 mV did not alter the I-V relationship. Peak Ca2+ conductance increased sigmoidally with increasing depolarization reaching half-maximal activation at -4 mV, with a maximal slope of 4 mV per e-fold change in Ca2+ conductance. 7. The kinetics of activation and inactivation of the Ca2+ current were voltage dependent and the time course of inactivation was fitted by the sum of two exponentials.(ABSTRACT TRUNCATED AT 400 WORDS)


Effects of perchlorate on excitation-contraction coupling in frog and crayfish skeletal muscle. 1. The effects of perchlorate on various aspects of excitation-contraction coupling in frog and crayfish skeletal muscle have been examined in optical and electrophysiological experiments on voltage-clamped cut muscle fibres. 2. In the frog, perchlorate shifted the voltage dependence of charge movement and consequent sarcoplasmic reticulum (SR) Ca2+ release, but it had little effect on the slow inward calcium current. 3. In the crayfish, perchlorate had little effect on either calcium currents or the SR Ca2+ release that contributes to myoplasmic Ca2+ elevations. 4. Two alternative explanations for these results are discussed. There may be two functional types of dihydropyridine receptors, those (perchlorate sensitive) that communicate with the ryanodine receptor via charge movement and those (perchlorate insensitive) that function solely as Ca2+ entry points. Alternatively, the results would be consistent with two separate voltage sensors on each dihydropyridine receptor, only one of which is perchlorate sensitive.


Hyperosmotic activation of the Na(+)-H+ exchanger in a rat bone cell line: temperature dependence and activation pathways. 1. The hyperosmotic activation of the Na(+)-H+ exchanger was studied in an osteoblast-like rat cell line (RCJ 1.20). The activation was monitored by recording the intracellular pH (pHi) changes employing double excitation of the pH-sensitive fluorescent dye 2'7'-bis(carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM). 2. Exposure of the cells to a hyperosmotic HCO(3-)-free medium at 37 degrees C produced an initial cytosolic acidification of 0.05 pH units followed by a lag period and an alkalinization overshoot of about 0.2 pH units, without a concomitant change of the free cytosolic calcium [Ca2+]i by the use of Fura-2 calcium-sensitive probes. This response was completely inhibited by amiloride (0.33 mM) or by Na+ depletion from the external medium and insensitive to the extracellular Cl- replacement, indicating the involvement of a Na(+)-H+ exchanger in the hyperosmotic response. 3. Hyperosmotic stimuli (200 moSM sucrose) applied in the temperature range of 17-37 degrees C demonstrated a shortening of the lag period preceding alkalinization and an increased rate of proton extrusion upon temperature elevation. The biochemical reaction underlying the lag period and the proton extrusion resulted in apparent activation energies of 19 and 29 kcal mol-1, respectively, as calculated from the appropriate Arrhenius plots. 4. Stimulation of the exchanger under isosmotic conditions by 25 nM 4 beta-phorbol 12-myristate 13-acetate (PMA) and 0.1 mM vanadate resulted in an amiloride-sensitive pHi increase of about 0.08 pH units. The hyperosmotic stress was additive to the stimulatory effects of these agents, suggesting an independent hyperosmotic activation pathway. 5. The hyperosmotic activation of the Na(+)-H+ exchanger was independent of cAMP, cGMP, cytosolic Ca2+ and protein kinase C. Thus, none of the classical transduction mechanisms seem to be involved directly in the hyperosmotic activation of the antiporter. 6. The pHi response induced by the hyperosmotic stress was abolished by two calmodulin inhibitors, W-7 and chlorpromazine (50% inhibition, Ki at 28 and 20 microM, respectively), 20 microM cytochalasin B, but not by 10 microM colchicine. The results suggest the involvement of actin and calmodulin-like structural elements of the cytoskeleton in the transduction process leading to the activation of the Na(+)-H+ exchanger.


ATP dependence of Na(+)-K+ pump of cold-sensitive and cold-tolerant mammalian red blood cells. 1. The ATP concentration of intact, cold-tolerant (ground squirrel) red cells and cold-sensitive (guinea-pig and human) red cells was monitored by use of the firefly tail, luciferin-luciferase assay. ATP kinetics of the pump in intact red blood cells was investigated by altering cell [ATP] by progressive depletion of ATP in the presence of 2-deoxy-D-glucose and then by measurement of ouabain-sensitive K+ influx at each level of [ATP] at various temperatures between 37 and 5 degrees C. Na(+)-K(+)-ATPase activity of broken membranes was also determined in parallel experiments using ouabain-sensitive release of 32P from [gamma-32P]ATP as a measure of activity. 2. Without depletion, there is no immediate decrease in [ATP] of intact cold-sensitive cells at low temperature (5 degrees C) at times when there are marked differences in the activities of the Na(+)-K+ pump of cold-tolerant and cold-sensitive cells. 3. At 37 degrees C Na(+)-K(+)-ATPase of all three species exhibited two components of ATP dependence at 37 degrees C, one with high velocity, low affinity, the other with low velocity, high affinity. Affinities of both components rose with cooling. 4. A similar, two component pattern was observed in intact guinea-pig and human red cells at 37 degrees C, except that the segment corresponding to the high affinity component had an apparent Km (Michaelis-Menten constant) 3- to 4-fold higher than that of the broken membrane preparation. 5. Cooling intact guinea-pig and human red cells decreased the apparent affinity of the high velocity, low affinity component for ATP, so that at 20 degrees C the value of Km approached or exceeded the levels of physiological ATP concentration. Below 20 degrees C only one component with values corresponding to that of the low velocity, high affinity component could be observed. 6. In intact ground squirrel cells only the low affinity, high velocity component was apparent between 37 and 5 degrees C. Its affinity for ATP rose with cooling between 37 and 5 degrees C.


Effect of colcemid on the water permeability response to vasopressin in isolated perfused rabbit collecting tubules. 1. The effect of the microtubule-disruptive agent, colcemid (N-deacetyl-N-methyl-colchicine), on the water permeability response to vasopressin has been investigated in isolated cortical collecting tubules from the rabbit kidney perfused in vitro. 2. Pretreatment of collecting tubules with colcemid inhibited the increase in water permeability elicited by vasopressin, 50 microU ml-1, in a time- and dose-dependent manner. After 75 min exposure to the drug, inhibition of the response to the hormone averaged 72 +/- 6% (n = 4, P < 0.01) at a colcemid concentration of 7.2 x 10(-5) M. Inhibition was estimated to be half-maximal at a colcemid concentration of 1.9 x 10(-6) M. 3. Colcemid, 2.7 x 10(-7) to 7.2 x 10(-5) M, had no effect on basal water permeability nor on the increase in lumen negative potential difference (PD) induced by the hormone. 4. Lumicolcemid, an isomer of colcemid that does not disrupt microtubules, had no influence on the water permeability response to vasopressin. 5. Pretreatment with colcemid, 2.7 x 10(-5) M, for 45 min inhibited the water permeability response to 8-CPT-cAMP, 1.8 x 10(-5) M, by 38 +/- 4% (n = 5, P < 0.01). 6. When collecting tubules were exposed to colcemid, 5.5 x 10(-5) M, for 45 min after the hydrosmotic response to vasopressin had been established, the drug had no influence on the maintenance of the raised water permeability. 7. The results provide further evidence that cytoplasmic microtubules play a role in the initiation of the hydrosmotic response to vasopressin in the mammalian collecting tubule at a site distal to the generation of cyclic AMP.


Influence of apical Na+ entry on Na(+)-K(+)-ATPase in amphibian distal nephron cells in culture. 1. Transepithelial Na+ transport, Na(+)-K(+)-ATPase activity and ouabain binding were measured in cells originating from the distal part of amphibian nephron (A6) which form 'tight' monolayers in culture, under standard (control) incubation conditions and after various manoeuvres designed to reversibly interfere with Na+ transport. 2. At spontaneous transport rate, the short-circuit current (which reflects transepithelial Na+ transport) and the Na(+)-K(+)-ATPase activity averaged 7.0 microA/cm2 and 5.9 mumol Pi/(mg protein.h), respectively (n = 53). Short-circuit current and Na(+)-K(+)-ATPase activity appeared to be directly related over a wide range. 3. Suppression of Na+ transport led to a progressive decrease in Na(+)-K(+)-ATPase activity over several hours, with an apparent half-life of approximately 6 h after subtraction of baseline enzyme activity. 4. When A6 cells were allowed to resume sodium transport, the short-circuit current and Na(+)-K(+)-ATPase activity returned to control levels within 12-24 h, the former recovering somewhat faster. 5. When apical sodium concentration was reduced, a decrease in enzyme level occurred inasmuch as short-circuit current decreased. 6. There was good agreement between the measured enzyme activity and ouabain binding onto dispersed A6 cells, which suggests that it is unlikely that the changes observed result from internalization vs. insertion in the plasma membrane of sodium pumps.


Interactions between Ca2+ mobilizing mechanisms in cultured rat cerebellar granule cells. 1. The interactions between IP3 receptor-mediated and Ca(2+)-induced Ca2+ release were investigated in cerebellar granule cell bodies, using the techniques of microfluorimetry and image analysis. 2. The IP3-sensitive Ca2+ release mechanism was activated using acetylcholine (ACh) and the selective metabotropic glutamate receptor agonist 1-aminocyclopentane-1S,3R-dicarboxylic acid (ACPD). Caffeine was used to activate, and ryanodine to inhibit, the Ca(2+)-induced Ca2+ release process. Thapsigargin was used to deplete intracellular Ca2+ stores. 3. Transient applications of caffeine (5-50 mM), ACPD (50-500 microM) and ACh (0.05-1 microM) mobilized intracellular Ca2+ ([Ca2+]i). Ca2+ mobilizing responses to 50 mM caffeine and 1 microM ACh increased with time in culture until day 4. However, beyond this period the responsiveness of cells to caffeine, but not to ACh, declined markedly. 4. Responses induced by ACPD and ACh were inhibited in the presence of caffeine at concentrations below those which mobilized Ca2+ (1-5 mM). This effect was not due to Ca2+ pool depletion, elevation of cAMP or inhibition of phosphodiesterases. 5. Prior challenge with ACh or ACPD inhibited Ca2+ mobilization induced by caffeine (50 mM). Transient exposure to caffeine inhibited subsequent responses to ACh through a mechanism which involved store depletion. 6. Thapsigargin (0.1-1 microM) inhibited, to a similar extent, Ca2+ mobilization induced by caffeine, ACPD and ACh. 7. Ryanodine (10 microM) antagonized Ca2+ mobilization induced by caffeine, ACh and ACPD. However, the ability of ryanodine to block inositol 1,4,5-trisphosphate-linked agonist responses varied considerably between cells. The sensitivity of ACh-induced responses to ryanodine correlated with the sensitivity of the cells to caffeine. 8. The possible explanations for the pronounced interactions between IP3 receptor-mediated and Ca(2+)-induced Ca2+ release processes in cerebellar granule cells are discussed.


Phencyclidine block of calcium current in isolated guinea-pig hippocampal neurones. 1. Phencyclidine (PCP) block of Ca2+ channel current in enzymatically dissociated neurones from the CA1 region of the adult guinea-pig hippocampus was studied using whole-cell voltage clamp techniques. Ca2+ channel current was recorded with 3 mM-Ba2+ as the charge carrier. Na+ currents were blocked with tetrodotoxin and K+ currents were eliminated by using tetraethylammonium and N-methyl-D-glucamine as the predominant extracellular and intracellular cations, respectively. 2. Peak Ca2+ channel current evoked by depolarization from -80 to -10 mV was reduced in a use-dependent fashion by PCP. The apparent forward and reverse rate constants for block at the depolarized voltage were 10(6) s-1 M-1 and 11-14 s-1, respectively. These values were at least 60 times faster than the corresponding rates at the resting voltage. The steady-state block produced by PCP increased in a concentration-dependent fashion with an IC50 of 7 microM. Other dissociative anaesthetic drugs were substantially weaker inhibitors of the current (tiletamine > dizocilpine (MK-801) > ketamine). 3. The Ca2+ channel current recorded under identical conditions in rat dorsal root ganglion neurones was less sensitive to blockade by PCP (IC50, 90 microM). 4. PCP block of the hippocampal Ca2+ channel current occurred in a voltage-dependent fashion with the fractional block decreasing at positive membrane potentials. Analysis indicated that the PCP blocking site senses 56% of the transmembrane electric field. 5. Analysis of tail currents recorded at -80 mV demonstrated that PCP does not affect the voltage-dependent or time-dependent activation or deactivation of the Ca2+ channel current. 6. The rate and extent of inactivation of the Ca2+ channel current was maximal at -10 mV and diminished at more positive potentials. Experiments with Ba(2+)-free external solution demonstrated that inactivation of the Ca2+ channels is largely voltage-dependent and is not affected by Ba2+ influx. 7. PCP markedly increased the apparent extent of inactivation of the Ca2+ channel current during prolonged voltage steps. This increase in apparent inactivation was more pronounced at depolarized potentials. Inactivation at -10 mV proceeded in two exponential phases; PCP had little effect on the fast decay phase and caused a moderate speeding of the slow decay phase. Although block of the activated state evolved on the same time scale as inactivation, the apparent rate of inactivation was not increased in a concentration-dependent fashion by PCP indicating that the block does not occur by a conventional open channel mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)


Colorectal cancer incidence among atomic bomb survivors, 1950-80. Colorectal cancer incidence in the LSS sample during 1950-80 was investigated. A total of 730 incidence cases of colorectal cancer were confirmed from a variety of sources. Sixty-two percent of the cancers were microscopically verified and 12% were ascertained through death certificate only. The risk of colon cancer increased significantly with intestinal dose, but no definite increase of risk was observed for rectal cancer. Relative risk at 1 Sv and excess risk per 10(4) PY-Sv for colon cancer are 1.80 (90% confidence internal 1.37-2.36) and 0.36 (90% confidence interval 0.06-0.77) respectively. City and sex did not significantly modify the dose-response of colon cancer, but the risk decreased with age at the time of bombings (ATB). The relative risk of colon cancer does not vary substantially over time following exposure. A non-linear dose response did not significantly improve the fit. Further, the anatomic location of the tumors indicate that the cecum and ascending, transverse and descending, and sigmoid colon seem equally sensitive to radiation. No difference in the distribution of tumor histological types could be observed by radiation dose.


Heterogeneity of rat hepatic Ah receptor: identification of two receptor forms which differ in their biochemical properties. In cytosol, the rat hepatic Ah receptor (AhR) appears to exist in two distinct forms (AhR alpha, AhR beta) in similar concentration. The binding of ligand (2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)) to AhR alpha requires the receptor be in its oligomeric 8-10 to S conformation (bound to other protein subunits), while ligand binding to AhR beta can occur with the dissociated 5-6 S form. Occupancy of AhR alpha by ligand (TCDD) protects it from salt-dependent inactivation; AhR beta is not inactivated by high salt conditions. The addition of molybdate to cytosol during tissue homogenization stabilized AhR alpha against salt-dependent inactivation and subunit dissociation but did not prevent dissociation of AhR beta by high salt. Although the presence of molybdate appears to stabilize AhR alpha in its oligomeric 8-10 S, it had no significant effect on the overall amount of TCDD:AhR complex which bound to its specific DNA recognition site, the dioxin responsive element (DRE). These results suggest that AhR alpha, unlike AhR beta, is either unable to transform or bind to the DRE with high affinity.


Sodium pump failure in hypoxia and reoxygenation. Sodium pump measurements have not been previously documented in the intact heart close to the onset of irreversible injury in hypoxia and reoxygenation. In the present experiments, Rb+ uptake was measured in the presence and absence of ouabain in Langendorff-perfused rat hearts. In the presence of ouabain, Rb+ uptake was increased after 10 min hypoxia (P < 0.05 vs. controls), but not after 30 min hypoxia, suggesting transient activation of a passive pathway such as the ATP-sensitive K+ channels. Passive Rb+ uptake was normal during post-hypoxic reoxygenation. Active Rb+ uptake was reduced after 30 min hypoxia, increased on reoxygenation after 10 min hypoxia, and failed to recover on reoxygenation after 30 min hypoxia (P < 0.001, P < 0.05 and P < 0.001, respectively, vs. controls). Sodium pump failure may lead to calcium overload through sodium-calcium exchange, and may be a decisive influence in post-hypoxic reoxygenation injury.


Distribution of gap junctions in dog and rat ventricle studied with a double-label technique. To assess the distribution of gap junctions in relation to the cardiac myocyte surface in paraffin sections of dog and rat ventricle, the sarcolemma was labeled with wheat germ agglutinin (WGA1) and gap junctions were labeled with antibodies to cardiac muscle gap junction protein connexin43. WGA labeled all of the myocyte sarcolemma, including that in intercalated discs and transverse tubules. Sarcolemmal WGA labeling was often interrupted at the sites of gap junctions, which were found both at the extreme ends of myocytes and along the length of adjacent myocytes. Small gap junctions predominated at plicate transverse portions of the intercalated disc; larger and sometimes ribbon-like gap junctions predominated at longitudinal portions. The longitudinal portions of the intercalated disc often extended over multiple sarcomere lengths, with ribbon-like gap junctions and linear arrays of smaller gap junctions arranged in parallel overlying successive sarcomeres. Morphometric study showed that ribbon-like gap junctions were relatively infrequent in both dog and rat left ventricular epimyocardium, and that animals with larger myocytes tended to have smaller gap junctions. In dog left ventricular epimyocardium, neither myocytes nor their larger gap junctions were randomly oriented with respect to perimysial separations; myocytes were usually somewhat flattened with their maximal diameters parallel to the separations, whereas large gap junctions were least often oriented parallel or perpendicular to the separations. Overall, the data indicate that myocyte geometry influences gap junction size and distribution; the double-label technique is ideally suited for the further exploration of that influence.


Calcium-activated force in a turkey model of spontaneous dilated cardiomyopathy: adaptive changes in thin myofilament Ca2+ regulation with resultant implications on contractile performance. Using saponin skinned fibers, we investigated whether decreased myofilament calcium responsiveness and contractile activation may in part contribute to heart failure in an animal model of idiopathic spontaneous cardiomyopathy (SCM). We addressed the question as to whether there are adaptive changes at the level of the thin myofilaments in turkey poults with SCM. The calcium concentration ([Ca2+]) required for 50% activation ([Ca2+]50%) was 0.80 +/- 0.12 microM (n = 12) vs. 0.76 +/- 0.08 microM (n = 12) and the Hill coefficient was 1.98 +/- 0.20 (n = 12) vs. 2.14 +/- 0.38 (n = 12) for control and SCM muscles respectively. Maximal Ca(2+)-activated force was not different between control fibers and fibers from failing hearts (3.83 +/- 0.88 g/mm2 vs. 3.65 +/- 0.39 g/mm2). These data indicate there are no differences in calcium-activation between fibers from control and failing myocardium. The effects of caffeine, an agent that increases myofilament Ca2+ sensitivity, were also studied. Addition of 10 mM caffeine resulted in a 0.06 pCa unit leftward shift of the force-pCa relationship in control hearts and 0.14 pCa units in SCM hearts. Caffeine (30 mM) increased force by 26 +/- 2.1% (n = 7) in control fibers and 44.5 +/- 8.7% (n = 8) in myopathic fibers at a pCa of 6.0. The increased responsiveness of muscles from failing hearts to caffeine indicates adaptive changes at the level of the thin myofilaments. Addition of dibutyryl-3',5'-cyclic-Adenosine Monophosphate (D-cAMP) resulted in a 0.21 pCa rightward shift on the calcium axis to higher intracellular calcium concentrations in control myocardium and 0.38 pCa units in SCM failing myocardium. The muscles were also sinusoidally oscillated at frequencies ranging between 0.01 and 100 Hz. In this analysis the frequency at which dynamic stiffness is minimum is taken as a measure of cross-bridge cycling rate. In control muscles, the frequency of minimum stiffness (fmin) was 1.20 +/- 0.11 (n = 4) whereas it was 0.71 +/- 0.08 Hz (n = 4) in myopathic muscles. The addition of 10 microM D-cAMP shifted fmin from 1.20 +/- 0.11 Hz to 1.68 +/- 0.09 Hz (delta = 0.48 +/- 0.06) in control fibers whereas in SCM fibers it caused greater shift of fmin from 0.71 +/- 0.08 Hz to 1.73 +/- 0.08 Hz (delta = 1.02 +/- 0.07). This differential effect of D-cAMP indicates adaptive changes at the level of the myofilaments.(ABSTRACT TRUNCATED AT 400 WORDS)


Mutation of E1 alpha gene in a female patient with pyruvate dehydrogenase deficiency due to rapid degradation of E1 protein. A mutation of an insertion of 4 bp in the gene for the alpha subunit of pyruvate dehydrogenase (E1 alpha) was found in a female with pyruvate dehydrogenase deficiency due to the rapid degradation of alpha and beta subunit proteins of pyruvate dehydrogenase. This mutation caused a frameshift that altered the amino acid sequence and created a premature stop codon. This 4-bp insertion has been found in an unrelated female patient with E1 alpha deficiency. It is rare that the same mutation is found in unrelated patients with this rare inborn error of metabolism. Furthermore, short deletions or duplications in the E1 alpha gene of patients with E1 alpha deficiency have been found only in exons 10 and 11. These exons may be hot spots for the mutations by the recombinational processes. This patient was heterozygous for the normal and a mutant allele. However, in most of the cultured skin fibroblasts from this patient, the mutant allele was expressed. These observations suggest that the X chromosome containing the normal allele was predominantly inactivated so that she developed lactic acidaemia and neurological abnormalities despite being heterozygous. The mutant alpha subunit protein failed to form a stable structure of pyruvate dehydrogenase, so that both alpha and beta subunit proteins were degraded rapidly.


Comparison of an endogenous protein kinase C substrate in rat aorta with rat brain MARCKS. We have compared the properties of a rat aorta-derived protein kinase C substrate (p75) with those of 80 kDa kinase C substrates from rat brain (MARCKS) and rabbit aorta (p80). Rat aortic p75 appeared to be closely related to rat brain MARCKS on the basis of: solubility in perchloric acid and trichloroacetic acid, heat stability, isoelectric point (pI approximately 4.2), overall V8 protease phosphopeptide map, and immunocrossreactivity with an antibody directed against the N-terminal domain of MARCKS. However, p75 could be distinguished from rat brain MARCKS and from the rabbit aorta-derived p80 on the basis of its consistently more rapid electrophoretic mobility in SDS-containing gels, and in terms of a unique proteolytic phosphopeptide found in MARCKS but not in aortic p75. We conclude that p75 probably belongs to the family of protein kinase C substrates represented by MARCKS, and that differences in post-translational processing (glycosylation) or mRNA processing may account for the unique properties of the p75 protein in rat aortic tissue.


Inhibition of ornithine decarboxylase and S-adenosylmethionine decarboxylase synthesis by antisense oligodeoxynucleotides. Oligodeoxynucleotides 18 nucleotides in length having sequences complementary to regions spanning the initiation codon regions of ornithine decarboxylase or S-adenosylmethionine decarboxylase mRNAs were tested for their ability to inhibit translation of these mRNAs. In reticulocyte lysates, a strong and dose dependent reduction of ornithine decarboxylase synthesis in response to mRNA from D-R L1210 cells was brought about by 5'-AAAGCTGCTCATGGTTCT-3' which is complementary to the sequence from -6 to +12 of the mRNA sequence but there was no inhibition by 5'-TGCAGCTTCCATCACCGT-3'. Conversely, the latter oligodeoxynucleotide which is complementary to the sequence from -6 to +12 of the mRNA of S-adenosyl methionine decarboxylase was a strong inhibitor of the synthesis of this enzyme in response to rat prostate mRNA and the antisense sequence from ornithine decarboxylase had no effect. The translation of ornithine decarboxylase mRNA in a wheat germ system was inhibited by the antisense oligodeoxynucleotide at much lower concentration than those needed in the reticulocyte lysate suggesting that degradation of the hybrid by ribonuclease H may be an important factor in this inhibition. These results indicate that such oligonucleotides may be useful to regulate cellular polyamine levels and as probes to study control of mRNA translation.


Screening for restriction endonucleases in methane-oxidizing bacteria. 51 methane-oxidizing bacteria strains such as Methylomonas methanica, M. rubra, Methylococcus capsulatus, M. thermophilus, M. luteus, M. ucrainicus, M. whittenburyi, Methylosinus trichosporium, M. sporium, Methylocystis parvus isolated from various ecological niches and geographical regions of the Ukraine and also the strains received from R. Whittenbury and Y. Heyer were screened for restriction endonucleases. Type II restriction endonucleases were detected in IMV B-3112 (= 12 b), IMV B-3027 (= 26), IMV B-3019 (= 9 c), IMV B-3017 (= 17 c), IMV B-3226 (= 26 v), IMV B-3033 (= Y), IMV B-3100 (= 100) and IMV B-3494 (= 1E494). The results obtained were indicative of relatively high frequency of restriction enzymes occurrence in methane-oxidizing bacteria. There were Kpn I (Asp 7181) restriction endonuclease isoschizomers in crude extracts of IMV B-3112, B-3017, B-3019, B-3027 isolated from fresh-water silt as well as in IMV B-3226 strain isolated from waste-water silt. Although these isolates had bee previously considered as untypical strains of M. ucrainicus, more detailed study of their properties allowed placing them with Methylovarius luteus (= Methylococcus luteus). IMV B-3494 strain was identified as Methylococcus capsulatus. Strain IMV B-3033 had earlier been allocated to Methylovarius whittenburyi (= Methylococcus whittenburyi). Specificity of restriction endonucleases of this strain was not tested. Therefore, for the first time restriction endonucleases were detected in methane-oxidizing bacteria. 8 strains (3 species) among 51 strains (13 species) were found to produce restriction endonucleases displaying three different types of specificity in the least. Producers of restriction endonucleases having Kpn I (Asp 7181) specificity were isolated from different water and silt samples of the Dnieper flood-land more than 20 years ago.


[The status and outlook of the laboratory diagnosis of rotavirus infection]. Rotavirus infection is not only the most distributed disease of children but a widely spread cause of their death. Nowadays considerable methodical potential which permits effectively detecting the whole virions, group A, antigens of human rotaviruses, virus-specific RNA in the clinical material is accumulated. There is a tendency to an increase of sensitivity and expressivity of the methods based on the use of immunological principles for detection and calculation of the antigen-antibody complex. Molecular-biological methods of the study are developed, which is important for the theory and practice of this infection control.


Viral infections in a sample of intravenous drug abuser prisoners. The Authors point out the high frequency of viral infections in a sample of IVDAs. The most significant infections that emerged are CMV and HCV diseases, in contrast with other epidemiological studies.


[Clinical characteristics of infections with cytomegalovirus in infants from personal observations]. An infection with cytomegaly virus had been diagnosed in 13 infants (including 4 neonates examined up to 2 weeks of life) out of 960 infants hospitalized within 3 years. Clinical examination most frequently revealed hepato- and splenomegaly, pneumonia and neurological disorders, and during a further stage of the clinical course psychomotoric retardation was noted in 7 out of 13 infants, and hearing loss in 5 out of 13 infants. A specific immunoglobulin G preparation (Cytotect) has been successfully used in all children, producing recovery or clinical improvement together with serologic improvement.


Recent progress in the molecular biology of Entamoeba histolytica. Entamoeba histolytica, a protozoan parasite causing human amoebiasis, has recently been found to comprise two genetically distinct forms, potentially pathogenic and constitutively nonpathogenic ones. Host tissue destruction by pathogenic forms is believed to result from cell functions mediated by a lectin-type adherence receptor, a pore-forming peptide involved in host cell lysis, and abundant expression of cysteine proteinases. Comparisons of these products from pathogenic and nonpathogenic E. histolytica suggest that they have evolved to serve functions in free-living or commensal behaviour. Isolation of the corresponding genes have provided the tools for detailed structural studies and manipulations of amoeba cell functions.


[A study on the regulation of ACTH secretion in rat pituitary cells]. In addition to method of ACTH RIA, a rat pituitary cell perfusion system was developed for the assessment of pituitary cells in stimulating and inhibiting ACTH secretion induced by some substances. Hypothalamic extract stimulated the ACTH secretion in a dose-dependent manner. AVP, cAMP, Ca2+, K+, noradrenaline, metoclopramide and haloperidol also had some stimulating effect. Dexamethasone and dopamine inhibited the basal ACTH secretion of pituitary cell and antagonized the effect of the various stimulating substances. Cyproheptadine could antagonize the effect of some of the stimulating substances while GABA had no marked inhibiting effect.


[The expression of kainate and GABA receptors in oocytes of Bufo bufo gargarizans]. Oocytes of Bufo bufo gargarizans were used as an expression system for analyzing structure of exogenous membrane protein and their functions. Poly (A)+ mRNA isolated from rat brain was injected into Toad (Bufo bufo gargarizans) oocytes (50 ng/oocyte). Rat brain kainic acid and gamma-aminobutyric acid(GABA) receptors expressed by the injected mRNA were integrated in the oocyte membrane 48 h after the injection at 19 degrees C. Membrane currents induced by kainic acid (5 x 10(-5) mol/L) and GABA (10(-4) mol/L) were 294.0 +/- 6.4 nA (n = 5) and 309.5 +/- 4.9 nA (n = 4) respectively. The kainic acid induced current reached its maximum value at about 10(-3) mol/L. Moreover, it was observed that the 36Cl- influx of the oocytes microinjected with mRNA was one-fold more rapid than the control oocytes. These results indicate that the oocytes of Bufo bufo gargarizans as those of Xenopus laevis can be used to express membrane proteins (receptors & transports) to acquire their proper functions from exogenous mRNA.


[The changes in transmembrane potential and ionic currents induced by "ischemia" in sheep cardiac Purkinje fibers]. Ischemia-mimic solution (hypoxia, hyperkalemia, acidosis, no substrate) induced changes of transmembrane potential and ionic current were observed in 24 sheep cardiac Purkinje fibers. The sequence of changes of transmembrane potential was as follows: Two to three min after perfusion with ischemia-mimic solution, the maximum diastole potential (MDP) was depolarized slightly, and attended by a decrease of depolarization rate of phase 4 while the action potential duration (APD) was shortened or underwent a shortening-prolongation-re-shortening process. Then, the plateau of action potential disappeared gradually. As MDP was depolarized further, the action potential amplitude (APA) and the excitability of the Purkinje fibers decreased continuously until action potential could no longer be elicited. The whole process took 30 min to 160 min in different preparations. When the APD was shortened, the instantaneous outward current was always increased at all membrane potential levels. The steady-state current-voltage relationship (CVR) curve was changed from S shape to a straight line, and the inward rectification phenomenon disappeared. Under ischemic condition, the amplitude of Isi was decreased from 6.74 +/- 4.48 nA to 0.86 +/- 1.39 nA, and the CVR curve shifted more to the negative. The above results indicate that under the ischemic condition, the pacemaker function of cardiac Purkinje cell is inhibited, a large amount of K+ ions outflows and inward current Isi is decreased. These changes may be the reasons for the genesis of ischemic arrhythmia.


[The relationship between Na overload and Na/H exchange--a study in the isolated isovolumic rat hearts]. Thirty min after stabilization perfusion with oxygenated buffer, hearts were divided in four groups: (1) CONTROL GROUP: 75 min. of aerobic perfusion; (2) Low flow anoxia group: 45 min. of low flow anoxic perfusion (95% N2:5%CO2, 0.15 ml/min.) followed by 30 min. of aerobic perfusion; (3) Ouabain group: protocol same as (2), except that ouabain (200 mumol/L) was added to anoxic perfusate during low flow anoxia; (4) Ouabain+Amiloride group: protocol same as (3) except that amiloride (0.5 mmol/I) was added to perfusate during low flow anoxia. Compared with the low flow anoxia group, ouabain resulted in an additional increase in Na during reperfusion accompanied with a depressed ventricular function. The deleterious effects of ouabain could be significantly combatted by amiloride. It is concluded that a decrease in Na/K ATPase activity may contribute to Na gain in reperfused myocardium, the mechanism of which might result from stimulation of Na/H exchange.


[Effects of injection of L-glutamate into the locus coeruleus complex area on the respiration]. Experiments were performed on 55 urethane anesthetized and flaxedil immobilized rabbits under artificial respiration. Injection of L-Glutamate into the locus coeruleus area led to a marked augmentation of respiration. This effect of L-Glutamate could be significantly attenuated or reversed by a previous injection of prazosin, yohimbine and propranolol into the NTS area. These results indicate that the neurons in the locus coeruleus are involved in the regulation of the respiration as a result of mediation by alpha and beta receptors in the NTS area.


GABAA receptors: ligand-gated Cl- ion channels modulated by multiple drug-binding sites. GABAA receptors are ligand-gated Cl- ion channels and the site of action of a variety of pharmacologically and clinically important drugs. In this review evidence is summarized indicating that these drugs, by interacting with several distinct binding sites at these receptors, allosterically modulate GABA-induced Cl- ion flux. Other results indicate that the affinity, as well as the modulatory efficacy of drugs, changes with receptor composition. A though investigation of the pharmacological properties of the individual binding sites on different GABAA receptor subtypes could open new avenues for selective modulation of GABAA receptors in different brain regions.


[Phosphoinositide metabolism and the formation of the calcium signal in cells]. The recent experimental data on the role of phosphoinositides in cellular Ca2+ signalling are reviewed. Mechanisms of receptor-mediated Ca2+ mobilization from the intracellular Ca2+ stores and pathways of Ca2+ entry in the plasma membrane are discussed.


Analysis of glucose repression in Saccharomyces cerevisiae by pulsing glucose to a galactose-limited continuous culture. In this study, glucose repression in Saccharomyces cerevisiae was analysed under defined physiological conditions, at both the molecular and physiological levels, by pulsing glucose to a galactose-limited continuous culture. During this pulse of glucose, the galactose feed was kept constant. Directly after the glucose pulse, carbon dioxide production increased while oxygen consumption remained constant, demonstrating that the surplus of glucose had been consumed by means of fermentation. The direct accumulation of galactose in the medium after the glucose pulse indicated that the consumption of galactose had been stopped instantaneously. Galactose uptake experiments revealed that the galactose transporter was still present but apparently was incapable of galactose uptake, which could be due to inhibition of the galactose transporter by glucose. The total concentration of cAMP increased from 5 nmol g-1 at t = 0 to 25 nmol g-1 at t = 1.5 min. After 2 min the concentration of cAMP gradually decreased again to the normal level. Within 2 min after the addition of glucose, the transcription of the GAL genes and SUC2 was inhibited. In addition, the transcription of the HXK1 gene, encoding hexokinase isoenzyme 1, was also inhibited, which demonstrates that the HXK1 gene is regulated at the transcriptional level comparable with invertase.


[Functional radiothermometry in the diagnosis of the autonomic dystonia syndrome]. The purpose of the study was to examine potentialities of functional radiothermometry in the diagnosis of a syndrome of vegetodystonia. 56 patients with vegetodystonia and 31 practically healthy subjects were examined. All the test subjects underwent the thermal radiothermometry test with the heating of the right hand and forearm in water bath at a temperature of 45-46 degrees C for 5 min and simultaneous recording of the temperature of the fingers of the intact hand. Analysis of the results demonstrated the predominance of manifest positive and negative temperature reactions in patients with vegetodystonia. In this patients' group, anxiety and hypochondria were encountered less frequently than in persons with moderate temperature deviations. Introduction of radiothermometry and psychological methods of examination allow planning the treatment in accordance with the signs of vascular and psychoemotional disadaptation.


[A psychoautonomic syndrome in the residual period of a modern "mild" military craniocerebral trauma]. As many as 18 patients with a history of military service in Afghanistan, who suffered (7.2 years before on the average) commotion due to the explosion wave were examined. The vegetative status was studied by different methods including cardiointervalography, as was the patients' emotional and personality sphere. The data obtained were compared to those obtained in three control groups (practically healthy subjects; those who suffered a mild home craniocerebral injury; healthy subjects who fought in Afghanistan and were not victims to craniocerebral injury). The main group patients demonstrated noticeable changes in the vegetative tone, vegetative reactivity and vegetative supply to physical activity as well as a high level of anxiety, which forms vegetodystonia. Attempts were made to correct the psychovegetative syndrome by central electroanalgesia in the tranquilization mode (9-10 daily sessions). The lowering of the tension of regulatory body systems functioning and the reduction of anxiety and depression tendencies were recorded.


[The function of neuromuscular structures and the cerebrospinal dynamics in primary arterial hypotension]. To specify correlations between neuromuscular, vegetative functions and CSF dynamics in patients with primary arterial hypotension, 22 young patients were examined with the aid of stimulation electroneuromyography, registration of evoked sympathetic cutaneous potential, echoencephalography and electrothermometry. The data obtained before and after antiorthostatic test were compared. A group of healthy subjects served as control. It has been shown that in patients with primary arterial hypotension with compensated neurological microsymptomatology, unpronounced under common conditions, there are well-defined signs of disorders in the work of neuromuscular structures, vegetative fibers, and in thermoregulation. These disorders undergo different changes under the influence of the antiorthostatic test and are accompanied in the majority of the patients by the enlargement of the ventricular system of the brain. It is assumed that in view of this fact, potentialities of adaptation are decreased in the disease in question. It is recommended that electroneuromyography and echoencephalography be used in an all-round estimation of the health status of patients suffering from primary arterial hypotension.


[The place and significance of the autonomic dystonia syndrome in the clinico-pathophysiological structure of the late sequelae of mild closed craniocerebral trauma]. Analysis of the incidence, clinico-pathophysiological structure and dynamics of vegetovascular disorders in subjects with a history of mild closed craniocerebral injuries has demonstrated that in the majority of them, even practically healthy, functional insufficiency of vegetovascular functions is seen for many years after injury. Clinically, it manifests under the influence of diverse harmful exo- and endogenous factors, undergoes circadian changes, is altered during magnetic storms, in the course of traumatic disease and nonmedicamentous correction (by methods of adaptive bioregulation according to heart rhythm parameters, craniocerebral hypothermia, etc). It has been shown that initially transitory, reversible vegetovascular disturbances, provided they were not initially removed, transform with years to more stable vegetotrophic disorders and become risk factor of cerebrovascular diseases in the given group.


[The role of autonomic dysfunction in the pathogenesis of lipid and lipoprotein metabolic disorders in patients with metabolic-alimentary obesity]. Obesity is a "disease of civilization" that leads to the formation of vascular pathology. Vegetodystonia, a heterogeneous syndrome both as regards the type and clinical course, is a pronounced clinical manifestation of obesity. The role of vegetodystonia in the formation of atherogenic potential of obesity has not been studied yet. 77 patients with metabolic alimentary obesity were examined for blood lipidograms as compared to the vegetative status and anthropometric data. Based on a correlation analysis performed, a relationship was discovered between the changes in the parameters indicated. The character of the correlation was determined by the type of vegetodystonia. The leading part in the formation of atherogenic potential is played by sympathoadrenal influences which are most manifest is permanent vegetovascular dystonia of the vagoinsular type. The treatment of obesity should be carried out with regard to the concrete variety of vegetative dysfunction.


[The characteristics of the autonomic disorders in acute cerebral circulatory disturbances]. The problem of the role of the autonomic nervous system (ANS) in the mechanism of symptom formation and in the pathogenesis of acute disturbances of cerebral circulation (ADCC) has not been studied well. Bearing this in mind, the authors examined 78 patients who suffered ADCC. The patients were divided into 2 groups. The first group was made up of 50 patients who suffered ischemic brain stroke with a stable neurological defect (SSD), the second one comprised 28 patients who suffered brain stroke with a reversible neurological defect (SRD). It has been established as a result that the initial level of sympatheticotonia and the intensity of the signs of vegetodystonia was higher in patients with SSD. Electrophysiological studies have demonstrated that in SRD, the level of ascending nonspecific brain activation prevailed according to the responsiveness of the reference alpha-rhythm as compared with the first group patients and the control group. The data obtained are discussed from the standpoint of the compensatory role played by the autonomic nervous system in the pathogenesis and course of the clinical forms of ADCC differing in the gravity and prognosis.


[A clinico-dynamic assessment of the structure of autonomic disorders]. The initial symptoms of vegetative crisis and the total number of symptoms in the intercrisis period were analyzed in 100 patients with paroxysmal permanent vegetative disorders. The most frequently occurring symptoms were defined and estimated from the standpoint of biological importance on which their higher sensitivity to pathogenic effects is based. The data obtained allow a conclusion about the necessity of differentiated symptomatic therapy.


[The pathogenetic and prognostic value of autonomic-hormonal shifts in ischemic stroke]. The paper deals with a study into the status of the autonomic nervous system and hormonal homeostasis in 58 patients with ischemic brain stroke. The blood content of cortisol, thyroxine, triiodothyronine and prolactin was measured by radioimmunoassay. The data obtained point to the differences in the degree of vegetative and hormonal imbalance depending on hemispheric lateralization of a pathological focus and the level of brain injury. The intensity of the vegetative and hormonal disorders correlates with the gravity of neurological deficit, with the development of secondary lesions of the cardiovascular system in cerebral dyshemia, being closely related to the disease outcome. The study creates prerequisites for the design of optimal methods of pharmacological correction of vegetative and hormonal dysfunction in patients with cerebrovascular diseases.


[The diagnostic significance of evoked cutaneous sympathetic potentials]. A study was made of evoked cutaneous sympathetic potentials in healthy persons, in simulation of emotional stress, in physical and orthostatic loads as well as during administration of 40 mg anapriline, 120 mg gangleron, and 15 mg diazepam. The purpose of the study was to identify factors that influence evoked cutaneous sympathetic potentials (ECSP). The mechanisms are reviewed of cutaneogalvanic reaction underlying ECSP. The data obtained were compared to those in patients with diabetes mellitus, Charcot-Marie amyotrophy, Guillain-Barré syndrome, Raynaud's disease, essential hyperhidrosis, panic attacks, and spinal amyotrophy. Analysis of ECSP makes it possible to reveal both brain function and primarily the presence of pathological alterations in the peripheral (segmental) autonomic nervous system.


[Autonomic vascular disorders in neuropathies and the methods for their pathogenetic therapy]. Investigations were made to examine vegetovascular disorders in patients with inherited and acquired neuropathies (regional vegetative innervation, peripheral circulation and the thermal status of the limbs). Comprehensive, pathogenetically based treatment methods were developed. Using clinico-neurological, thermography, rheovasography and electrothermography research methods the following alterations were revealed in the autonomic areas of innervation of affected nerves: the signs of vegetovascular irritation; the signs of vegetovascular depression; a phenomenon of thermovision "amputation". Bearing in mind the diagnostic data, the patients were given differentiated pathogenetic therapy including physiotherapy and vegetotropic drugs.


[The clinical polymorphism of autonomic crises (panic attacks)]. Overall 42 patients with vegetative crises (panic attacks) were subjected to a clinico-psychopathological analysis. In the structure of the crisis together with 14 typical symptoms (in accordance with DM-III criteria), account was taken of 11 atypical symptoms represented by functional neurological phenomena ("chunk" in the throat, weakness in the limbs, mutism, loss of consciousness, and so forth). Depending on the correlation of the typical and atypical symptoms in the crisis 3 subgroups were distinguished. In subgroup A, the portion of the typical symptoms as regards the typical ones was less than 30%, in subgroup B, it was from 30 to 50%, and in subgroup C over 50%. The characteristic features of the crises and of the interparoxysmal period were compared in the above-indicated subgroups. The comparative analysis has demonstrated the same representation of the typical symptom-complex in all the three subgroups and allowed one to identify definite clinical features characteristic of each of the subgroups.


[HLA antigens in persons with a predisposition to frequent sympathetic-adrenal paroxysms]. Comparison of the rate of HLA antigens I in 81 patients with frequently occurring sympathoadrenal paroxysms (SAP) associated with vegetovascular dystonia and 113 healthy subjects revealed the increase of the number of antigen B12 carriers among the patients as compared to the healthy subjects' group. The number of antigens A9, B35 in SAP patients was elevated whereas that of B18, B38 and B40 decreased. SAP related to age-associated hormonal rearrangements were marked by antigens Cw4 and A1, the grave SAP patterns by B12, SAP without nocturnal paroxysms and the early disease onset by the lack of antigen A19. The dominant gene that determines the onset of SAP is localizes in the HLA area. It may be associated with a hypothetical gene analogous to the locus implicated in the determination of the threshold of neuromuscular excitability of rats. It is not excluded that such a relationship is mediated via the blood content of Mg2+.


[An analysis of the autonomic manifestations of Raynaud's phenomenon by the spectrum of heart rhythm variability]. A study was made of the specificity of segmental and suprasegmental vegetative disorders seen in patients with Raynaud's phenomenon (RP). The sympathetic-parasympathetic interrelations were estimated according to the dynamics of the spectral constituents of heart rhythm under different functional conditions. There was a decrease of the sympathetic activity modulated by the stem and segmental mechanisms, accompanied by activation and rigidity of the suprasegmental ergotropic systems, leading to a stable vasospasm on the periphery. This may determine the low efficacy of vegetotropic peripheral drugs and a higher therapeutic effect of psychotropic drugs which reduce ergotropic activation.


[Autonomic disorders in parkinsonism].

[Autonomic disorders in parkinsonism]. The authors analyze the clinical and paraclinical manifestations of vegetative disorders in parkinsonism. It is shown that vegetative disorders are relatively independent of motor parkinsonism manifestations and run their course by the type of concomitant sympathetic and parasympathetic insufficiency. Injury to the segmental and suprasegmental mechanisms of motor control underlies vegetative disorders. The role of segmental and suprasegmental disorders in degenerative diseases of the nervous system with marked vegetative manifestations is analyzed and compared.


[The clinical and computed tomographic criteria of the diagnosis of multiple systemic cerebral atrophy with progressive autonomic insufficiency (the Shy-Drager syndrome)]. Based on clinical and CT examination of 3 patients with Shy-Drager syndrome and the reported data, differential diagnosis of the given diseases is under discussion. Shy-Drager syndrome is characterized by CT signs of progressive atrophy of the pons and cerebellum with no essential changes in the supratentorial brain structures. The authors support a proposal to use the term "multiple systemic atrophy" for designation of the disease entity that includes both Shy-Drager syndrome and sporadic patterns of olivopontocerebellar and strionigral degenerations in which the disease debuts by motor disorders of the extrapyramidal and cerebellar nature rather than by vegetative disturbances.


[The genetic aspects in the genesis of autonomic crises (panic attacks)]. In 30 patients with vegetative crises (VC) (the structure of the crises met DSM-III criteria for panic attacks), the typing of histocompatibility (HLA) antigens was carried out. Antigen HLA-Cw6 was found in 53% of the patients (in 10% in controls [pc < 0.01]). The relative risk of VC in persons having antigen Cw6 is 10.3. The data obtained allow regarding antigen HLA-Cw6 as of potential genetic markers of VC.


[Autonomic disorders in the formation of the clinical manifestations of the initial forms of cerebrovascular lesions]. Among 103 persons aged 20 to 57 years, related occupationally to emotional stress, 48 persons were found to have vegetative dystonia, 28 initial manifestations of cerebral circulation failure, and 27 persons appeared healthy. The determination of the character and intensity of vegetative manifestations has shown that in the formation of vegetative dystonia, of paramount importance are cardiovascular and gastrointestinal disorders. Vegetative manifestations associated with initial manifestations of cerebral circulation failure include, in addition, respiratory disturbances and impairment of sleep function, which may reflect more deep changes in the activity of the regulatory apparatus in dyshemias of organic nature. A relationship was discovered between vegetative lesions and emotional disorders, particularly the level of anxiety, as was the contingency of vegetative dysfunction and decreased emotional stress tolerance.


[Peripheral autonomic insufficiency in the Guillain-Barré syndrome]. Overall 11 patients with acute inflammatory demyelinating polyradiculoneuropathy or Guillain-Barre syndrome were examined for the status of the peripheral part of the autonomic nervous system. Methods used in the study permit estimating the status of vegetative fibers in different systems: in the cardiovascular system, in the pupil, and in sweat glands. Part of the patients were examined over time for all the vegetative and electroneuromyographic characteristics. Based on the data obtained the conclusion is made about a slow recovery of the function of vegetative fibers in the cardiovascular system. It is emphasized that the degree of vegetative fibers injury and, therefore, the gravity of the clinical manifestations and the course of vegetative polyneuropathy are determined in many respects by the degree of axon impairment.


[A clinico-physiological analysis of essential hyperhidrosis]. A total of 30 patients with essential hyperhidrosis (EH) and 20 healthy test subjects were examined. Based on the anamnestic and clinical data the patients with EH were distributed into 2 groups: permanent EH and remitting EH (PEH and REH respectively). REH and PEH patients manifested disorders of the suprasegmental part of the autonomic nervous system, which showed up by a rise of the level of reactive and personality anxiety, an increase of the readings of the MIL test scales. PEN patients demonstrated segmental vegetative disorders that manifested by reduced conduction in sweating fibers (a method of evoked cutaneous sympathetic potentials), a lowering of sympathetic effects in the cardiovascular system, a decline of diurnal excretion of catecholamines. The conclusion is made about the presence of 2 forms of EH: permanent EH and remitting EH that differ in the degree of involvement of the suprasegmental and segmental parts of the autonomic nervous system into the pathological process. Based on the reduced conduction in the sympathetic sweating fibers in PEH patients the conclusion is drawn that denervation hypersensitivity to blood catecholamines plays a great role in the pathogenesis of the given pattern of EH.


[Autonomic nervous system function in men with cerebrovascular insufficiency against a background of hormonal rearrangement]. As many as 33 men with initial manifestations of brain blood supply insufficiency and transient disorders of brain circulation associated with cerebral atherosclerosis were examined for the vegetative characteristics (tone in the cardiovascular system, reactivity, physical activity supply) during age-associated hormonal rearrangement. RIA was used to measure the blood serum content of peripheral sexual hormones (testosterone, estradiol) and the content of gonadotropic hormones of the pituitary (follicle-stimulating and luteinizing). It has been revealed that the hypersympathetic direction of vegetative functions is combined with remarkable changes in the content of sex steroids in the form of testosteronemia and hyperestradiolemia. This dictates the necessity of correcting the function of the autonomic nervous system and the hormonal status.


[Transient psychogenic psychoses in servicemen]. To specify the clinical picture, criteria for differential diagnosis and for medicolegal estimation of transitory psychogenic psychoses, 26 servicemen admitted irresponsible in respect to the actions committed in a state of psychosis were examined. Responsible servicemen who committed crimes in a state of physiological affect (n-26) or at the moment of acute situational personality reactions (n-26) were examined as reference groups. It has been established that transitory psychogenic psychoses occurred in servicemen with a definite personality and mental disposition (inhibited pathocharacteristic features and phenomena of residual organic brain injury) in a chronic (from 3 to 12 months) psychotraumatizing situation of permanent ill treatment and humiliation, causing long sleep deprivation. 3 stages were distinguished in the development of psychosis: stage I (preneurotic) was partial mental disadaptation; stage II (neurotic) involved further development of the phenomena of partial disadaptation and was characterized by well-defined asthenoneurotic and depressive dysphoric syndromes and not infrequently by syndromes of autistic aggressive fantasies; stage III was complete mental disadaptation marked only by transitory psychoses. The latter stage was short-lived (commonly lasting several hours), characterized by psychotic depth and by unmarked phenomena of agitated depression and pathological interpretations. Psychogenic psychosis that occurred in the presence of the above symptoms manifested, as a rule, by a depressive raptus with severe psychomotor excitation, vital melancholy, fragmentary hyperquantivalent depressive delirium, and phenomena of deep depersonalization and derealization.


[The neurophysiological indices of neurotic patients with different types of individual character and their dynamics during group psychotherapy]. Based on the clinical and neurophysiological studies analysis is made of the prognostic importance of character accentuations as the most important factor of the personality premorbid condition of neurotic patients. 107 patients with different patterns of neuroses, who underwent group psychotherapy (a personality-oriented (reconstructive) variety). Analysis of the dynamics of the neurophysiological characteristics, made during group psychotherapy, supported the clinical data on varying curability of neurotic patients with different types of character accentuations. Patients with the hysteroid type character accentuation appeared more resistant to psychotherapy. In patients with the sthenic variety of hysteroid accentuation, the positive dynamics was recorded in but 30% of cases, in the asthenic variety of hysteroid accentuation, in 48.6% of cases. Patients with inhibited character traits turned out more pliable to group therapy. In the sensitive type accentuation, the positive dynamics of the neurophysiological characteristics was established in 65% whereas in psychasthenic accentuation, in 72% of cases. The neurophysiological correlations of the main types of character accentuations and their dynamics during group psychotherapy were also revealed.


[The characteristics of the emotional disorders in patients with neuroses]. To study the structure of emotional disorders, 90 neurotic patients were examined. Analysis of the intensity and incidence of different emotions was made with the help of self-estimation cards. It has been established as a result that the structural basis of emotional disorders is formed by primary and secondary negative emotions. Different patterns of neuroses are characterized by specific structural features.


[A comparative evaluation of the biochemical and psychopathological characteristics in subjects with signs of pedophilia]. RIA was employed to examine 54 test subjects who committed sexual crimes with regard to children of tender age. A syndrome of sexual perversions in the form of pedophilia was discovered in 42 persons. Different patients' groups manifested significant differences in the content of hypophyseal and sexual hormones in the blood serum. A significant lowering of testosterone was revealed in persons with heterosexual pedophilia and with pedophilia without any aggressive and sadistic disorders. They also demonstrated a high prolactin content.


[Nonpsychotic neuropsychic disorders as a basis for abnormal behavior in younger schoolchildren]. As many as 110 junior schoolchildren with abnormal behavior, whose parents had taken advice of the psychiatrist, were examined. In the majority of cases, behavioral abnormalities were due to borderline residual organic disorders; more rarely, they involved characteristic and pathocharacteristic reactions including those seen in personality deviations or were related to mental diseases. Disinhibited behavior is mostly determined by biological factor whereas opposition and hysteroid behavior tends to positive correlation with microsocial factor. The majority of children with abnormal behavior, especially in the presence of low intellect and speech disturbances have a negative attitude to school. Some general recommendations are given to parents of difficult children.


[Autonomic disorders in the clinical picture of gastric and duodenal peptic ulcer and their acupuncture reflexotherapy]. Patients with peptic ulcer demonstrate diverse psychovegetative disorders that complicate the course of the somatic disease. Depending on the intensity of psychovegetative disorders the following syndromes were distinguished: astheno-neurotic, astheno-hypochondriac, astheno-depressive and psycho-vegetative with organic microsymptomatology. The use of laser puncture in multimodality therapy of peptic ulcer patients favours correction of vegetative disorders and normalization of regenerative processes occurring in the gastroduodenal system.


[A new verbal projective method for studying personality]. The authors have designed two variants of the "verbal projective test" (VPT) in view of the lack of a projective method genetically similar to the TAT, according to which, however, emotionally saturated, indefinite phrases as regards the content could be used as stimulus material. Theoretically, it could be of special interest in psychopathological cases associated with thinking disorders, as well as "compensate" for the tendency toward TAT aging. Using VPT 19 probands with little progressive neurosis-like schizophrenia and 19 probands with lingering neuroses were examined. The findings were estimated polyfactorially in terms of the main assumptions of TAT interpretation but with a mandatory inclusion into the analysis of the lexico-grammatical evaluation of the stories. It has been established in the course of the work that the leading differences in the delimiting of neuroses and little progressive neurosis-like schizophrenia are emotional disorders (their character and intensity) diagnosed, equally to certain thinking disorders, with the aid of the new method. It has been also shown that the new VPT is fit for analysis of the speech of the persons suffering from various mental disorders.


[Problems in the pathomorphosis of neuroses]. Overall 2,991 case reports of patients who stayed at the department for neuroses and psychotherapy during 1948-1988 underwent a clinico-socio-psychological analysis. Certain aspects of interisomorphism, intranosomorphism and intersyndromic pathomorphism of neuroses for the 40-year period are indicated. It is assumed that the main causes of pathomorphism as applicable to the patterns of neuroses are social and psychological mechanisms whereas the dominant syndrome is the combination of individual psychological factors with social and psychological ones as well as organic insufficiency.


[Protracted reactive states in the general hospital: the clinico-psychopathological aspects]. A study was made of earthquake-induced mental disorders which did not lead to the patients' admission to psychiatric hospitals. 40 patients were examined at the general somatic hospital 6-7 months after the earthquake. The signs of mental disorders of the neurotic and affective level were revealed in 70% of the patients with lingering reactive conditions. They manifested in asthenic, depressive hypochondriac and conversion syndromes. All the cases were characterized by asthenic disorders and somatized nature of the disorders.


Effectiveness of chemical agents in removing platinum from DNA isolated from cisplatin-treated HL-60 cells. Human promyelocytic leukemia cells, HL-60, were treated with cisplatin [cis-diamminedichloroplatinum (II)] (2 mM, 1 h). DNA-cisplatin-protein complexes were isolated and exposed to thiourea (1 M), NaCN (100 mM), diethyldithio-carbamate (500 mM), or N-methyl-D-glucamine dithiocarbamate (500 mM) for 12 h. The release of platinum was measured by atomic absorption spectroscopy. Sodium cyanide was the most effective agent, releasing about 90% of the DNA-bound platinum. Thiourea was the least effective agent, while dithiocarbamates exhibited an intermediate. The ability of the same group of agents to split the proteins off from the protein-cisplatin-DNA complex was also evaluated and similarly dithiocarbamate were also the most effective.


A preliminary study of correlation of immuno-histological and ultrastructural characteristics of neural granuloma in leprosy patients. With an aim to better understand the pathogenesis of nerve damage in leprosy, peripheral nerve biopsies from six untreated leprosy cases (3 BT/TT and 3 BL/LL) were studied by electronmicroscopy and immuno-histology. In addition to routine histopathology for diagnosis, infiltrating cells of granuloma were characterized after preparation of single cell suspension. The lymphocytes in the lesion were characterized by E and EAC rosetting and macrophage phagocytic system (MPS) cells were studied using histochemical markers like esterase and peroxidase. The results indicate that the lymphocyte content was significantly greater in tuberculoid neural granuloma compared to lepromatous nerves and these formed rosettes with sheep erythrocytes (E) and expressed HLA-DR antigen suggesting that they are activated T cells. Infiltrating macrophages in both the tuberculoid and lepromatous neural granuloma were esterase positive, peroxidase negative and did not form rosettes with sheep erythrocytes or EAC. Ultrathin sections of tuberculoid granuloma showed lymphocytes clearly associated to epithelioid macrophages having well developed Golgi apparatus and rough endoplasmic reticulum. Correlation of these immunological and ultrastructural characters suggests that hypersensitivity mechanisms are possibly responsible for nerve damage in tuberculoid leprosy. Ultrastructural examination of lepromatous nerves, on the other hand, showed the predominance of macrophages with large nucleus, heavily bacillated Schwann cells, and a few lymphocytes. The correlation of immuno-histological and ultrastructural characters indicates that the mechanism(s) of nerve damage in lepromatous leprosy are basically different wherein hypersensitivity appears to play a very limited role.


[Antiarrhythmic effects of kappa-seleno-carrageenan in experimental animals]. The effect of Kappa-seleno-carrageenan, an organic compound containing selenium, on aconitine, BaCl2 and ouabain-induced arrhythmias were studied. When rats were given ip 9 mg.kg-1.d-1 x 5 d or ig single dose of 35, 70, 140 mg.kg-1, the threshold dose of aconitine was elevated significantly to induce HA. The effect seems to resemble that of ip Na2SeO3 1 mg.kg-1 x d-1 x 5 d. With increasing ig dose, the threshold dose of aconitine was elevated for inducing VE, VT, VF. When ip 9 mg.kg-1 x d-1 x 5 d or ig 70 mg.kg-1 was given, the threshold doses of BaCl2 in inducing VF (in rats) and ouabain in inducing VE (in guinea-pig) were elevated. However, no influence was observed for ip Na2SeO3 1 mg.kg-1 x d-1 x 5 d.


[Typing of human papillomavirus (HPV) in the male and female genitalia]. Diagnosis and typing of HPV was started in November 1990 at the Virology department of the National Health Institute, Lisbon. Eighty one samples from 70 patients were studied, 57 from women observed at the cervico-vulvar out patient unit of the Gynecology department of Sta Maria Hospital, Lisbon, and 13 from male contacts of some of these women. Forty nine women (86%) had colposcopic, histological or cytological evidence of HPV infection. Eleven men (85%) have clinical signs of infection and 2 (15%) had had sexual intercourse with infected partners with clinical evidence of infection. HPV DNA was detected in 43 patients (61%). Forty two were infected with HPV 6/11 (98%) and one with HPV 16 (2%). These preliminary results suggest that genital infection by HPV must also be considered a public health problem in the field of sexually transmitted diseases in Portugal.


[Malpighian epithelia and papillomavirus infections]. Human papillomaviruses (HPV) are a large group of DNA viruses, with over 60 types identified to date, which can cause the development of benign tumors in the skin and mucosal squamous epithelia. Most of these tumors regress spontaneously but some, especially in the mucosal membranes, become malignant. HPV types with a high risk for inducing malignancies (e.g. 16 and 18) are the subject of increasing interest. HPVs are both host-specific and tissue-specific: some types preferentially infect specific epithelia, giving rise to lesions with distinct topographic characteristics. HPVs are difficult to study because they do not replicate in available in vitro models. In vivo, HPVs replicate well in epithelial cells undergoing terminal differentiation, e.g. in keratinized cells. Some 40 different types have been reported in epidermal keratinocytes, the most common being types 1 and 2 which produce large amounts of viral antigens and viral particles. In contrast, HPVs replicate poorly in the weakly keratinized squamous epithelia which line the digestive, respiratory, and genital tracts. Junctional epithelia, e.g. on the uterine cervix, are especially prone to HPV infection. The most prevalent HPV types in benign genital lesions are types 6 and 11, whose characteristic features include extrachromosomal DNA and production of only small amounts of viral antigens. The profound nuclear and cytoplasmic changes induced by HPVs lead to the formation of koïlocytes which are found mainly in the granular layer of epithelia and have been especially well described in the uterine cervix and vagina. HPV epithelial tumors are squamous cell carcinomas that often harbor HPV types 16 and 18; this is especially true of cervical intraepithelial neoplasias. These tumors contain the viral DNA, which may or may not be integrated into the cellular DNA, whereas viral antigens are lacking. The high incidence and broad spectrum of HPV types found in patients with acquired immunodeficiencies (e.g. under immunosuppressive therapy) suggest a key role for cellular immunity in the development of HPV-induced lesions. A number of cofactors, including UV radiations and smoking, as well as oncogene activation and anti-oncogene inactivation, may increase the risk of progression to malignancy.


[Malignant fibrous histiocytoma with giant cells of the skin. Anatomoclinical and immunohistochemical study of a case]. The authors report a case of malignant giant cell soft tissue tumor which appeared as a skin tumor of the thigh in a Tunisian women aged 17 years. Immunohistochemical study showed that the giant cells recognized KP1 antibody, while spindle interstitial cells reacted with anti-factor XIIIa antibody. The patient is alive and well eighteen months after large surgical removal. Two similar cases have been reported in the literature. Differential diagnosis, histogenesis and prognosis of this rare tumor are discussed.


[Simultaneous detection by non-isotopic in situ hybridization of human papilloma viruses and Epstein-Barr virus during the lytic cycle in oral hairy leukoplakia lesions]. Oral hairy leukoplakia is almost only described in patients infected by the human immunodeficiency virus. Epstein-Barr virus, sometimes associated with human papillomavirus, is always involved in the occurrence of these lesions. We have investigated two cases of oral hairy leukoplakia with the goal of detecting EBV and HPV by using both in situ hybridization and immunohistochemistry. EBV genome was detected with biotinylated BamHI W cDNA probe in the two cases. Furthermore, EBV was found to be in lytic phase as demonstrated by the strong signal observed with FITC-labelled anti-sense BHLF1 oligonucleotide probes. This finding was further supported by the absence of labelling with EBV-latent-cycle markers such as EBER1/2 oligoprobes and anti-latent membrane protein 1 antibody. In addition, these two cases were positive for HPV genomes: 31-33-51 (n = 1) and 31-33-51 plus 6-11 (n = 1) as detected by in situ hybridization using different sets of biotinylated probes. The signal obtained with in situ hybridization (both HPV and EBV) was localized to the upper layers of epithelial cells. The mechanism of oral hairy leukoplakia remains still unknown, but this work emphasizes the value of in situ hybridization with nonisotopic probes in the detection of viral nucleic acids on routinely processed tissue sections. The fact that these lesions seem to precede the AIDS phase emphasizes the clinical implications of this diagnosis in HIV infected patients.


EEG findings in West syndrome a follow-up of 20 patients. Clinical and EEG findings of 36 patients with West syndrome (WS) were reported. Twenty patients (7 males, 13 females; mean age 7.4 months at the first EEG examination) were followed for a mean period of 19.3 months. Fifty per cent of the 8 cases with cryptogenic SW showed a full recovery, 2 cases showed persistence of psychomotor retardation or seizures and 2 of both these features. At the end of follow-up period, 92% of the 12 patients with symptomatic WS showed a psychomotor retardation and 75% a persistence of seizures. EEG pattern was a typical hypsarrhythmic one in 11 patients and atypical in the remaining cases. The typical pattern correlated with a better outcome with full recovery in 27.3% compared with 11.1% in the group with atypical EEG. Moreover EEG monitoring was useful for the evaluation of therapeutic response and in the follow-up of the disease, showing a correlation with clinical course, incidence of spasms and outcome.


[Pyrophosphate-dependent inactivation of tyrosyl-tRNA synthetase during aminoacylation of heterologous tRNA]. It has been shown that heterologous aminoacylation of tRNA by tyrosyl-tRNA synthetase leads to inactivation of the enzyme. Inorganic pyrophosphatase prevents the inactivation and increases the enzyme activity and aminoacylation level in a heterologous system. A putative inactivation mechanism is discussed.


New insights on the pathogenesis of neurodegenerative disorders. In the last few years, an increasing amount of studies have been dedicated to the etiopathogenesis of age-related neurodegenerative disorders, such as Parkinson's disease, amyotrophic lateral sclerosis and Alzheimer's disease. The discovery of synthetic, as well as natural molecules, able to reproduce in the animals biochemical and morphological alterations of neurodegenerative disorders, has provided a major impetus to the "environmental" hypothesis of neurodegeneration. In this review, following a brief description of the ability of the nervous system to counteract the degenerative process, the main neurotoxic-based animal models for neurodegeneration are examined. These might give us interesting clues for understanding the pathogenetic mechanism(s) of neurodegenerative process.


Hepatic glycogen depletion in fed female rats induced by piroxicam. The effects of i.p. piroxicam administration on hepatic glycogen levels and enzymatic activities of key enzymes involved into glycogen metabolism in fed female rats were studied. Liver glycogen concentrations in treated rats decreased with increasing time of treatment and doses of piroxicam administered. The fall in glycogen caused by piroxicam persisted for several days after it was discontinued. Neither nadolol nor phenobarbital administration were able to prevent the depleting effect of piroxicam. In the treated rats, glucose-6-phosphatase, glycogen phosphorylase and glycogen synthase activities remained unchanged respect to control. Also, proportion of phosphorylase in the active (a) form was not significantly affected by successive piroxicam daily doses. In contrast, we demonstrated a decrease in the glycogen synthase in the active I form. This reduction was time-dependent on piroxicam treatment. Further, glucose loads were not capable to restore activity in the synthase enzyme and liver glycogen synthesis in animals treated with piroxicam. The impairment into glycogen metabolism produced by piroxicam administration suggests liver becomes unable to maintain glucose homeostasis. Furthermore, glycogen depletion might produce an impairment in the metabolism of drugs administered simultaneously with piroxicam, because biotransformation of xenobiotics is a process depending on glycogen storage in the liver cells.


Batter up! Relapse prevention for homeless veteran substance abusers via softball team participation. Thirty-four veterans of a residential rehabilitation program for homelessness and substance abuse participated on a community-based softball team. Compared to nonparticipants, participants stayed in treatment longer and were more likely to complete all aspects of the program (inpatient and outpatient). They also were more likely to be abstinent from drugs/alcohol, employed, and housed 3 months postdischarge. Participation appeared to enhance outcomes by providing in vivo opportunities for practicing coping skills and developing supportive relationships. A softball program may be a viable adjunct treatment in which formally taught cognitive-behavioral skills can be applied in a natural, but semistructured setting.


Characterization of apoptosis-like endonuclease activity in avian thymocytes. In the current study the internucleosomal DNA cleavage activity associated with apoptosis was investigated in avian thymocytes. Thymocyte nuclear proteins from glucocorticoid-treated chickens were incubated with chicken red blood cell (cRBC) nuclei, and DNA degradation was analyzed by agarose gel electrophoresis and fluorescence-activated flow cytometry. The thymocyte nuclear extract contained an endonuclease activity that degraded cRBC chromatin at internucleosomal sites as detected by agarose gel electrophoresis. Flow cytometry analysis of cRBC nuclei that were treated with thymocyte nuclear proteins demonstrated a loss of cellular DNA as a function of the amount of added nuclease activity. Furthermore, it was demonstrated that the thymocyte nuclear extract contained a nuclease activity that was capable of degrading radiolabelled naked 32P-DNA into acid soluble DNA fragments. All three assay methods demonstrate that the thymocyte nuclease activity can be inhibited by EDTA, zinc ions and the nuclease inhibitor aurintricarboxylic acid. Based on the analysis of cofactor requirement of this nuclease activity and its susceptibility to inhibitors, the endonuclease activity present in avian apoptotic thymocytes appears to be identical to the mammalian counterpart.


Free radicals in physiology and pathology. Free radicals are molecules with odd number of electrons and a high instability. Free radicals, which can occur in both organic (i.e., quinones) and inorganic molecules (i.e., O2-), are very reactive and their reactions are critical for the normal activity of a wide spectrum of biologic processes. They are also produced in the catalytic action of a variety of cellular enzymes and electron transport processes and are implicated in a number of physiologic and pathologic processes. Organisms can be exposed to free radicals in many ways other than through the processes of normal metabolism. Irradiation of organisms with electromagnetic radiation generates primary radicals (e-aq, OH., and H.), which can then undergo secondary reactions with dissolved O2 or with cellular solutes. In addition, a wide variety of environmental agents (drugs capable of redox cycling, and xenobiotics that can form free radical metabolites) including the aging process cause free radical damage to cells. This review deals with the reactions they can undergo and discusses the free radicals related to toxicology.


Selective protonic activation of isomeric glycosylfructoses with pyridinium poly(hydrogen fluoride) and synthesis of spirodioxanyl oligosaccharides. Selective activation of the ketose unit in the isomeric glycosylfructoses, palatinose, leucrose, maltulose, turanose and lactulose, with pyridinium poly(hydrogen fluoride) resulted in the almost quantitative formation of glycosylated difructose dianhydrides. The reaction preferentially involves a reactive fructofuranosyl oxocarbenium ion and is subject to stereoelectronic control. The relative amounts of isomeric spirodioxanyl oligosaccharides obtained within a series was shown to depend on the reaction conditions, especially on the hydrogen fluoride-pyridine ratio. Using suitable concentrations of hydrogen fluoride in pyridine, the reaction was easily directed to the formation of the kinetic difuranosyl or thermodynamic pyranosyl derivatives. More rigorous conditions resulted in the specific hydrolysis of one glycosidic bond in the tetrasaccharides derived from palatinose, leucrose and turanose, to yield spirodioxanyl trisaccharides.