Spontaneous and bile salt stimulated bile secretion in the Adelie penguin (Pygoscelis adeliae). The flow rate and ionic composition of bile during spontaneous secretion were measured in anaesthetized penguins in which the enterohepatic circulation had been interrupted and with i.v. injection of saline to replace secretory loss. During the first two hours the rate of flow increased, and then remained relatively constant for a further two and a half hours. During this time the concentration of bile salt fell, but the concentrations of other ions showed small fluctuations only. Sodium taurocholate increased the rate of bile flow and the excretion of ions, except that of bicarbonate. Sodium taurolithocholate initially produced cholestasis but later apparently increased bile flow and had an overall choleretic effect. It is suggested that the active excretion of bicarbonate ions by the bile ducts is the predominant regulator of bile secretion in the penguin.


Prolonged effects of a post-synaptic blocking fraction of Naja siamensis venom of skeletal muscle of the mouse. A sublethal dose of a post-synaptic blocking fraction of Naja siamensis venom was injected into the soleus muscle of the mouse inhibiting neuromuscular transmission for 2-3 days. The paralysed soleus muscle behaved as if denervated, developing extra-junctional sensitivity to acetylcholine and accepting innervation by an implanted foreign nerve. Since the only known action of the post-synaptic blocking fraction of this venom is due to its affinity to acetylcholine receptors, the results suggest that the spread in the sensitivity of muscle fibres to acetylcholine and their ability to accept a foreign nerve is a consequence of neuromuscular blockade.


Vagally induced gastric antral contractions and gastric emptying of a liquid test meal. The emptying of a liquid test meal from the stomach was studied during, and in the absence of, electrical stimulation of cut ends of a thoracic branch of the vagus in anaesthetized cats. The test meal (154 mmol.1-1 NaCl and 30 mg.1-1 phenol red) was measured by collecting effluent from a duodenal fistula over a 30 min period. The stomach emptied about 60% of the meal under control conditions compared with over 90% during efferent stimulation of the vagus. The increased volumes emptied during efferent stimulation were not accounted for by secretion of gastric acid. Coincident with the vagally evoked antral contractions there was a gush of liquid from the duodenal cannula. Afferent vagal stimulation resulted in an initial marked delay of emptying followed by an acceleration so that the volume emptied after 30 min was similar to that in control experiments. Antral contractions, evoked by efferent vagal stimulation, accelerated the emptying of a liquid test meal from the stomach.


Secretory, motor and vascular effects in the sublingual gland of the rat caused by autonomic nerve stimulation. The influence of the autonomic nerves on sublingual glands of rats was studied. Stimulation of the chorda-lingual nerve evoked a lively flow of saliva and was also thought to contract the myoepithelial cells in the gland. Sympathetic nerve stimulation, on the other hand, usually evoked no secretion and did not cause any motor responses in the sublingual gland. The glandular blood flow was increased by chorda-lingual nerve stimulation, and this vasodilatation persisted also when atropine had been administered. Sympathetic nerve stimulation decreased the sublingual blood flow; this vasoconstrictor effect was mediated via activation of alpha-adrenoceptors.


The effects of reducing dietary nitrogen and of increasing sodium chloride intake on urea excretion and reabsorption and on urine osmolality in sheep. Renal responses to reducing dietary nitrogen were studied in four ewes during intravenous infusion of arginine vasopressin. The fall in urea excretion and in plasma urea concentration was accompanied by significant reduction in GFR and in urine osmolality. The fraction of filtered urea reabsorbed increased despite reduction in the urea U/P concentration ratio and this increase was sustained when the urea U/P ratio was further reduced at higher urine flows observed when the drinking water was replaced with saline. This procedure also sustained the RPF which in the absence of additional salt was significantly reduced on the low protein diet. It is suggested that the fall in GFR and the increase in the fraction of filtered urea reabsorbsed may contribute to nitrogen economy and that the increase in fractional reabsorption and the reduction in urine osmolality on the low protein diet provided evidence of active reabsorption of urea by renal tubules.


The effects of urea infusion on glomerular filtration rate and renal plasma flow in sheep fed low and high protein diets. Reducing the dietary N intake of sheep resulted in a significant fall in GFR with no change in RPF. Intravenous of urea for 19-46 h had no effect on the high protein diet but on the low protein diet GFR and FF were increased to values approaching those observed on the high protein diet. On the low protein diet GFR was unaffected by infusion of urea for 4 h or of saline alone for 30 h. It is suggested that the observed changes in GFR are associated with changes in the quantity of protein passing to the abomasum and small intestine.


Effect of high fluoride intake on haematological aspects of the mouse. The effect of feeding adult Swiss albino mice of both sexes a diet supplemented with 0, 125, 250 and 500 parts/10(6) of fluoride for four and eight week periods on haemoglobin concentration (Hb), packed cell volume (PCV) and mean corpuscular haemoglobin concentration (MCHC) was investigated. Values of the three parameters were significantly lowered at both periods in the treated groups as compared with the controls. The extent of reduction in these values was, in general, dependent on the dose of supplemented dietary fluoride. Clinical symptoms were not observed before the end of the sixth week. However, appearance of the symptoms did not change the trend of variations in Hb, PCV and MCHC values. The reduced values could be the result of lowered haemoglobin synthesis and erythropoiesis. It was suggested that these haematological indices could serve to detect preclinical effects of high fluoride intake with an added dose of as low as 125 parts/10(6), or even less, for a period of four weeks or probably earlier.


Effect of sub-diaphragmatic vagotomy on gastric mucosal mast cell population in pylorus ligated rats. Gastric mucosal mast cell population was studied following sub-diaphragmatic vagotomy in albino rats, 6 and 12 h after pylorus ligation. Sub-diaphragmatic vagotomy significantly increased the gastric mucosal mast cell population in both 6 and 12 h groups, the increase being more in the latter. The results suggest that the vagal impulses act on the gastric mucosal mast cells causing their degranulation. Following vagotomy the contents stay bound within the mast cells. Increase in mast cell population with the longer experimental situation was possibly due to the continuation of normal turnover of the mast cells in the gastric mucosa. The present study, however, does not lead to a conclusion that the vagal influence on mast cell population is similar throughout the gastro-intestinal tract.


The absorptive viability of isolated intestine prepared from dead animals. Glucose and water absorption rates are much lower (50%) in isolated perfused rat small intestine when the animals are killed by stunning or ether before removal of the intestine than when the animal is maintained alive under light ether anaesthesia throughout the setting-up procedure.


Use of 1alpha-hydroxycholecalciferol in the prevention of bovine parturient paresis. A synthetic biologically active derivative of vitamin D (350 microgram of 1alpha-hydroxycholecalciferol [1alpha(OH)CC]) was injected into 2 nonlactating 7-year-old Israeli-Friesian cows. Plasma calcium values increased after 24 hours, peaked at 48 hours, and returned to base-line values 120 hours after injection. An injection of 350 microgram of 1alpha(OH)CC was given to 23 parturient-paresis-prone Israeli-Friesian cows from 7 days to 6 hours prepartum; 13 cows were injected once, 6 were injected twice, and 4 were injected 3 times, all at 48-hour intervals. Parturient-paresis-prone cows (n = 23) of the same breed were used as controls. Within 0 to 36 hours postpartum, plasma calcium concentrations were found to be higher in cows injected with 1alpha(OH)CC than in the control cows. The increase was highly significant (P less than 0.01) in cows injected at least twice. None of the cows injected with 1alpha(OH)CC, within 72 to 24 hours prior to calving developed parturient paresis; but 9 of 23 control cows developed parturient paresis. Prior to calving, none of the injected cows developed hypercalcemia and there was no local or systemic clinically detectable signs of toxiosis. When given at the right time prepartum, 1alpha(OH)CC is considered to be an improvement over previous methods of preventing bovine parturient paresis.


A brush-border-bound peptidase and amino acid transport. Aminopeptidase when in its integral form interacts with lecithin to form a stable lipoprotein complex. The reconstituted system is a single-bilayer vesicle about 30 nm in diameter. The hydrophobic part of the amphipathic hydrolase is incorporated in the lecithin bilayer with the portion carrying enzymic activity oriented towards the external aqueous phase. This part can be detached by proteases.


Intestinal mucosal hydrolysis of proteins and peptides. The major products of intraluminal hydrolysis of dietary proteins appear to be small peptides and amino acids. Recent studies indicate that the distal part of the small intestine may play an important role in the digestion and absorption of dietary proteins. Intestinal mucosal cellular hydrolysis of peptides and proteins represents the terminal stage of digestion of dietary proteins and appears to be carried out predominantly by amino-oligopeptidases in brush border membranes and cytoplasm. These enzymes in the two main subcellular loci are distinct since they exhibit different electrophoretic mobilities, physicochemical properties, substrate specificities and responses to starvation and dietary manipulation. Two amino-oligopeptidases have been purified from the intestinal brush border of the rat. The enzymes are remarkably similar to each other in many respects. They have an apparent molecular weight of 280 000 and are composed of two subunits of equal molecular weight. Both enzymes are glycoproteins having similar chemical compositions, common antigenic properties, substrate specificities and kinetic properties.


Intestinal brush border peptidases.

Intestinal brush border peptidases. A brush-border-specific antiserum was raised in rabbits, with Triton X-100-solubilized brush border proteins from pig intestine being used as antigens. The antiserum was used in immunoelectrophoretic studies of brush border proteins solubilized with Triton X-100. Five immunoprecipitates were obtained which corresponded to microsomal aminopeptidase (EC 3.4.11.2), asparate aminopeptidase (EC 3.4.11.7), lactase (beta-galactosidase, EC 3.2.1.23), maltase (exo-1,4-alpha-glucosidase, EC 3.2.1.3) and sucrase-isomaltase (sucrose alpha-glucohydrolase, EC 3.2.1.48). A faint immunoprecipitate was also found for the glycylprolyl dipeptidyl peptidase (EC 3.4.14.-). The brush border proteins were solubilized on a large scale from a brush border membrane preparation by the use of Triton X-100; the peptidases obtained were homogeneous in size and had hydrophobic properties. By chromatography on columns of concanavalin A-Sepharose, hydroxyapatite, Ultrogel AcA 34, DEAE-cellulose and immunosorbent, gamma-glutamyl transpeptidase (gamma-glutamyl transferase, EC 2.3.2.2) and microsomal aminopeptidase were each isolated in separate fractions. Glycylprolyl dipeptidyl peptidase and asparate aminopeptidase were obtained in another fraction. Immunoelectrophoretic, inhibitor and chromatographic studies showed that the intestinal brush border peptidases are similar to the corresponding particulate peptidases obtained from other organs.


Intracellular hydrolysis of peptides.

Intracellular hydrolysis of peptides. Purification of the first dipeptidases, glycylleucine dipeptidase (EC 3.4.13.2) and proline dipeptidase (EC 3.4.13.9), from intestine, have shown them to be true dipeptidases, hydrolysing only dipeptides in their laevo form. Although they have quite different specificities they show great similarities in their chemical and physicochemical properties. Specific antibodies against the two dipeptidases have been raised and used in combination with the double-layer immunofluorescent staining technique to study their histological localization in the small intestine. The results conclusively demonstrated that both glycylleucine dipeptidase and proline dipeptidase are exclusively located in the cytosol of the enterocytes. This location fits well with the current idea of transport and hydrolysis of dipeptides in the intestine where the dipeptides are taken by a specific transport mechanism and are hydrolysed intracellularly. Although it is tempting to add a specific role for the dipeptidases of the enterocytes in the final digestion of exogenous proteins, studies so far have shown their identity with the corresponding dipeptidases of other tissues. It is therefore suggested that their role in the digestion process may be based entirely on their abundance in the intestine.


Endopeptidases in the brush border of the kidney proximal tubule. Among the five peptidase known to be located in the microvillus membrane of the renal proximal tubule are two enzymes with endopeptidase activity. Neutral endopeptidase, a zinc-dependent enzyme, has a broad specificity comparable to that of thermolysin, and like the latter may be specifically inhibited by phosphoramidon. Dipeptidyl peptidase IV, a serine enzyme, is very sensitive to inhibition by diisopropyl phosphorofluoridate. It is also capable of endopeptidase activity, hydrolysing bonds involving the carboxyl group of proline.


Clearance of dipeptides from plasma: role of kidney and intestine. The metabolic fate of glycylglycine and glycyl-L-leucine administered intravenously to rats, and the processes involved in the clearance of these dipeptides from plasma, have been studied. The dipeptides disappeared rapidly from plasma without being lost in the urine or accumulating in body tissues, but concentrations of glycine or leucine, or both, increased markedly in plasma and body tissues. All tissues except blood had considerable hydrolase activity against Gly-Gly and Gly-Leu, with kidney and intestine being far more active than liver and muscle in this regard. When uptake of glycylsarcosine, which is resistant to hydrolysis, was investigated after intravenous injection, its disappearance from plasma was slower than that of Gly-Gly, but Gly-Sar accumulated in all tissues examined (liver, muscle, renal cortex and intestinal mucosa). Its concentration in the renal cortex far exceeded (over 14-fold) that in other tissues, and a considerable portion of the injected Gly-Sar dose appeared in the urine. Bilateral nephrectomy did not have a remarkable effect on the plasma half-life of Gly-Leu or Gly-Gly but markedly prolonged that of Gly-Sar. Nephrectomy also allowed greater tissue accumulation of Gly-Sar and recovery of Gly-Gly and Gly-Leu from tissues. The plasma half-life of Gly-Gly was also not remarkably affected by total enterectomy. These studies suggest that (a) clearance of dipeptides from plasma is chiefly a function of tissue uptake and hydrolysis, and (b) among dipeptides, those resistant to hydrolysis depend to a great extent on kidneys for their clearance from plasma.


Peptiduria in the Fanconi syndrome.

Peptiduria in the Fanconi syndrome. Peptide excretion has been studied in 20 cases of Wilson's disease and in maleate-induced Fanconi syndrome in the rat, ligand-exchange column chromatography being used to separate peptides from free amino acids. There is a statistically significant increase in urinary peptides in both types of the Fanconi syndrome. In both man and the rat, a large fraction of the excreted peptides has been shown to contain hydroxyproline, and therefore to be derived from collagen degradation. In both groups there is a close correlation between the output of hydroxyproline and that of total peptide-bound amino acids. Arguments are advanced that the peptiduria is due to increased urinary clearance of plasma peptides rather than to a metabolic cause. Peptides excreted in patients with the Fanconi syndrome are shown to have a different proportionate amino acid composition to those in urine specimens from normal controls. The mean size of urinary peptides derived from collagen must be at least five or six amino acids per peptide chain. Maleate-induced Fanconi syndrome in the rat is thought to be a close analogue of the syndrome in man, and further results obtained in the animal model may well be directly applicable to human disease.


Introduction. Membrane transport of peptides. Carrier-mediated membrane transport of small peptides is now realized to be a process of wide biological distribution, occurring not only in the small intestine and elsewhere in the animal body but also in bacteria, yeast, the mould Neurospora crassa, and probably in higher plants during the germination of seeds. The important features of peptide transport are outlined, and possible relationships between peptide transport and hydrolysis are discussed. Peptide transport is a stereochemically specific active process, and is independent of the transport of free amino acids. It is frequently, though not always, more rapid than the transport of amino acids. In the intestine, it is probably limited to dipeptides and tripeptides, but certain other animal cells and bacteria can take up larger peptides of seven or more amino acid residues. The ability to take up small peptides on a large scale is nutritionally important in some microorganisms, and might be of nutritional importance to the intact animal and to animal cells in culture. In the absorptive cells of the small intestine, and in Escherichia coli, peptide transport into the cells is followed by intracellular hydrolysis; transport and hydrolysis are quite distinct processes. Whether hydrolysis and amino acid transport can be coupled processes, or whether peptide transport and hydrolysis are different aspects of the same process, remains to be seen. This question is one of those where a close integration of studies of peptide transport with those of peptide hydrolysis should be particularly helpful.


Dipeptide transport in the intestinal mucosa of developing rabbits. Influxes of glycyl-L-proline (a dipeptide which is not hydrolysed in the membrane and is transported intact across the brush border) and of glycyl-L phenylalanine (a dipeptide which has affinity for the peptide transport system and is hydrolysed at the brush border membrane) have been studied in the small intestine of fetal, newborn and suckling rabbits. For glycyl-L-phenylalanine, transport as the intact dipeptide and 'membrane hydrolysis + amino acid transport' have been measured separately by using glycyl-L-proline and L-leucine as selective inhibitors of each pathway. For comparison, uptake of free glycine and of free phenylalanine has also been studied. The intestine of newborn rabbits is shown to have a translocation process for intact dipeptides which is saturable with a low Kt and stimulated by sodium ions, and which is not shared by free amino acids. This process resembles that described in adult animals, except that the maximal velocity is much higher in newborns. The developmental pattern of this uptake process for dipeptides differs markedly from that of free glycine, thus providing a new type of evidence for the distinction between amino acid and dipeptide transport processes. The developmental pattern of the free phenylalanine uptake process also differs from the development of the 'superficial hydrolysis + amino acid transport' component of glycl-L-phenylalanine uptake. These data suggest that the advantage of mucosal uptake of peptides, compared to the uptake of free amino acids, is much greater in the early stages of postnatal life than in the adult.


The effect of temperature on the lateral diffusion of plasma membrane proteins. Cooling is expected to gradually reduce the lateral diffusion of membrane proteins, at a rate predicted from the changes in viscosity and order observed on cooling defined lipids and lipid mixtures. However, a continuous change in diffusion rate with falling temperature is not observed in mammalian cells. Rather, on cooling below around 20 degrees C, protein diffusion rates are found to increase, reaching a new maximum at 15 degrees C. This anomaly in diffusion rate could result in irreversible changes in membrane structure when mammalian cells are cooled to temperatures below 20 degrees C.


Factors affecting the survival of sheep embryos during-freezing and thawing. The survival of sheep morulae and early blastocysts after deep freezing has been investigated. With a dimethyl sulphoxide concentration of 1.5 M in a phosphate-buffered saline medium, a freezing rate of 1 degreees C/min down to 120 degees C allowed embryos to survival only if rapid thawing (approximately 360 degrees C/min) was employed, whereas with a freezing rate of 0.3 degrees C/min, survival was obtained with both rapid and slow (10 degrees C or 4 degrees C/min) thawing. With even slower freezing (0.1 degrees C/min over intervals between -30 and -60 degrees C) slow thawing was no longer optional but mandatory. With the latter technique survival rates of the order of 80% were obtained. The results of transfer experiments with frozen-thawed sheep and cattle embryos are briefly presented in an Appendix.


Where did our infectious diseases come from? The evolution of infectious disease. Infectious diseases have been evolving from the earliest days of life on earth. Major factors influencing their developments include the splitting of continents (continental drift), the radiation of early primates into present-day forms, migrations of man around the world, the ending of the Ice Age, the invention of agriculture, the domestication of animals, the increase in populations, and the urbanization of societies. The impact of such basic changes on infectious diseases is reviewed.


Epidemiology of infectious disease: the example of measles. The situation of unacculturated Brazilian Amazon tribes is described. The isolation of these populations has been sufficiently tight that they have been free of most epidemic diseases of the cosmopolitan world, although diseases associated with persistent infection have a high prevalence. The history of measles epidemics in Amerind populations is reviewed and it is concluded that most deaths can be prevented by basic nursing care but that there is a residual excess mortality characteristic of these populations. Three Brazilian virgin-soil populations and one experienced tribe in Chile, the Mapuche, were vaccinated against measles. Elevated febrile responses were observed in the three virgin-soil populations relative to the fevers seen in the Mapuche and in cosmopolitan populations. Nutritional status, immunological experience, humoral immune response and genetic characters have been examined for an explanation of this phenomenon. The most pronounced correspondence detected so far is a high degree of homozygosity in HLA loci of the virgin populations.


The freezing of mammalian embryos: perspectives and possibilities. Since the Ciba Foundation Symposium in 1952 on Mammalian Germ Cells when Dr Audrey Smith reported that 'exposure to very low temperatures is not incompatible with further development of mammalian eggs', much progress has been made on the problem of freezing mammalian embryos. The significant steps leading to this progress are reviewed and an attempt is made to assess the extent of our current knowledge and to relate this to experience gained in other fields of low temperature biology. There is good evidence that certain basic principles concerning cooling and warming rates are applicable to the preservation of all mammalian embryos so far studied, but differences between species and between stages of development within species exist, particularly in their resistance to cooling in temperature ranges above 0 degrees C. Some of these differences are illustrated by reference to experiments with pig embryos. Clearly there are many problems remaining to be solved, but practical applications of techniques for long-term storage of mammalian embryos are already feasible and offer interesting possibilities for future development.


Aspects of infection in isolated communities. Respiratory viruses are not generally carried by normal subjects and cannot persist in small isolated communities. When infection does occur epidemics are seen and the illness may be more severe than in the outside world. These points are illustrated by reference to studies on the island of Tristan da Cunha and stations of the British Antarctic Survey.


Some factors affecting embryo storage in laboratory animals. Various factors affect the viability of embryos after freezing and thawing. When mouse embryos are supercooled below -6 degrees C before ice induction (seeding), survival is markedly reduced, apparently by inadequate dehydration of the embryos during subsequent cooling. Immediately after thawing, eight-cell mouse embryos and blastocysts experience a delay before normal embryonic development is resumed. A restorative period in culture combined with a modification of the synchrony between embryo and recipient helps to maximize survival following transfer. No loss of viability was observed in eight-cell mouse embryos after storage at -196 degrees C for four years. The preservation of the embryos of laboratory species other than the mouse and rabbit is limited by our lack of knowledge of the culture requirements for the development of such embryos.


Health and disease in unacculturated Amerindian populations. The stereotype of uncontacted tribal populations is that they must reproduce at near capacity to maintain or slightly increase their numbers. This paper argues that the health of minimally contacted Amerindians, as judged by the results of physical examinations and life tables for the Yanomama of Southern Venezuela and Northern Brazil, is relatively good, with population control a feature of the Indian culture. It is further argued that the usual deterioration in health with contacts with western culture probably does not result so much from special innate susceptibilities to certain epidemic diseases and to the diets and 'stresses' of civilization as from the epidemiological characteristics of newly contacted peoples.


The Kren-Akorore: a recently contacted indigenous tribe. Primitive groups of people, living in complete isolation, are rarely encountered these days. In fact, the process of 'approximation', or contact, depends upon decisions made on both sides--that representing the civilized world and that representing the group called by us 'primitive'. The isolated group, however, can never perceive the tremendous risks its members will inevitably encounter one the barrier of isolation, by which they are protected, has been broken. Civilized man has the means of persuasion and attraction at his disposal and also knows the risks involved. It must therefore be his responsibility to protect and preserve the group right from the initial contact. In spite of the medical resources available, primitive man has paid heavily in human lives through contact with the civilized world. This raises two equally important question: (a) have medical resources been thoroughly applied to protect these groups? And (b) are the existing medical resources sufficient to ensure the survival of primitive man once his state of isolation has been broken? Without any definite answers to these questions, we are limited to describing our experiences with the Kren-Akorore Indians, recently contacted in Central Brazil. We also present data on the biological characteristics of these Indians, collected two years after the first contact.


Diet and nutrition of hunter-gatherers.

Diet and nutrition of hunter-gatherers. The diets and nutrition of hunter-gatherers are discussed with the !Kung Bushmen (San) of the Dobe area, Botswana as the example. In general they show no qualitative deficiency of specific nutrients though they are thin and may be undernourished (by our standards) at some seasons. They show little or no obesity, dental caries, high blood pressure or coronary heart disease; their blood lipid concentrations are very low; and they can live to a good old age if they survive infections or accidents.


Beliefs and behaviour in disease.

Beliefs and behaviour in disease. Isolated tribal communities depend on the resources available where they live and on knowledge to use them well, which is passed on by education and training in cultural skills. Anthropological studies have recorded the successful adaptations achieved in some societies. This paper discusses notions akin to those of contagion and infection as they are understood by people in a community in New Guinea. Do they show in these ideas the accurate observation and deduction apparent in their other adaptive achievements? The people have approved patterns for behaviour to maintain health and heal illness. Is the behaviour seen to be effective by them? It may not seem so to the outside medical observer but it is not rejected by the people, who must use it in coping self-reliantly with their circumstances. The question of prognosis is discussed from their point of view so as to show problems which they face in responding to opportunities of modern medical care and in judging the efficacy of treatment.


Medical practice and tribal communities. Recent studies are discussed of societies in which medical procedures, involving injections and other modern techniques, are carried out by unqualified practitioners. These practitioners are discussed from the point of view of the sociology of health care.


Pitfalls to avoid: the Australian experience. In this paper the major health problems facing Australia's Aboriginal population are reviewed and an attempt is made to assess the genetic and environmental, social and cultural factors to which they may be attributed. Among Aborigines living in remote areas under semi-tribal conditions, recent improvements in health, though considerable, have not been commensurate with the greatly increased expenditure on health and welfare services. This disappointing outcome is due partly to loss of control by Aborigines over their own lives, including matters concerning health, and partly to failure of white medical and welfare personnel to communicate with people holding different beliefs about health and disease. The bad health of Aborigines living in cities and rural areas can be attributed largely to their poverty, which in turn stems from discrimination in employment, housing and community services. In both the remote and the settled areas health services for Aborigines are increasingly coming under the control of Aborigines themselves and producing encouraging results.


The responsibilities of intervention in isolated societies. Development pressures are pushing industrial society into the remaining refuge areas of the world. As it spreads it destroys much of the biological and cultural variety that has evolved over millions of years. Not only is mammalian life diminishing, but also the genetic pool of plants and cultivars, as well as the culture-specific knowledge of their use. Even culture itself, the highest attribute of mankind, is being rapidly erased, often before any attempts are made to record it. The medical problems of remaining tribal groups are severe. Western medicine has developed to deal with western problems and is often poorly equipped to deal with the many-sided health hazards of tribal man. The effects of contact upon disease status are discussed with particular reference to North and South American Indian history. Infectious disease is only one of many causes of ill-health, and the problems of nutritional change and social disruption are also considered. The approach to health care in tribal communities is discussed and axioms for the initiation of health care programmes are proposed.


Field methods for the assessment of health and disease in pre-agricultural societies. The few surviving pre-agricultural societies preserve the best available indication of human adaptation during more than 99% of the species' history. The field methods described allow collection of data that may explain why hunters and gatherers are physically small in the face of apparent plenty, what causes their death and how they control population growth. Observations of daily life, especially family, food and work, provide the context within which biological data can be interpreted. Computer-compatible event-recording systems make possible the collection and encoding of quantitative behavioural observations. A careful census permits characterization of fertility and mortality. Physical assessment, by medical history, physical examination and anthropometry, establishes the patterns of growth and development in the population and the prevalence of clinically recognizable diseases and nutritional disorders. If blood, urine or faeces can be collected, lightweight portable field-proven equipment and techniques are available for the collection, analysis and preservation of specimens for biochemical, nutritional, haematological and genetic determinations.


Some characteristics of tribal peoples.

Some characteristics of tribal peoples. The study of health and disease in distinctive human groups is an important source of knowledge, and ultimately of understanding. Tribal societies are at the polar extreme from modernized communities. However, with the breakdown of isolation this distinctiveness is being eroded, slowly for genes, more rapidly for ideas and behaviour, and fastest for infective agents of disease. Though comtemporary tribal men cannot be equated with prehistoric men, they resemble them more than do modernized men. Therefore the study of tribal peoples not only widens the range of circumstances in which human adaptability is observed, it throws some light on the evolution of human diseases. This is particularly the case with regard to the study of 'diseases of modern life'. Tribal life is characterized by comparative physical and cultural isolation, simplicity, small group size, low population density and closeness to nature, both physically and conceptually. In spite of rapid change, which itself needs study, there are still situations where what is studied has shown little recent change. In a world where dissatisfaction with life and medicine grows in spite of unparalleled technical success, we should look again at tribal men. There is much to learn from each other's successes and failures.


Effect of polyamines on isoleucyl-tRNA formation by rat-liver isoleucyl-tRNA synthetase. The effect of polyamines on rat-liver isoelucyl-tRNA formation was studied using isoleucyl-tRNA synthetase purified by column chromatography successively on Sephadex G-200, DEAE-Sephadex A-25, and tRNA-Sepharose 4B. In the presence of 50 mMK+, isoleucyl-tRNA formation was inhibited markedly by 1.5 mM or higher concentrations of Mg2+. However, the addition of spermine to the reaction mixture prevented the inhibitory effect of Mg2+. In the presence of 200 mMK+, the addition of spermine to the reaction mixture stimulated isoleucyl-tRNA formation in the presence of Mg2+ concentrations from 0 to 5 mM. Although the effective concentration was different, spermidine exhibited a similar stimulative effect. The effective concentration of spermine required for stimulation was higher when larger amounts of tRNA were used. The stimulatory effect of isoleucyl-tRNA formation by polyamines was shown to reflect on polypeptide synthesis. When formaldehyde-treated poly(A,U) was used as messenger RNA, polypeptide synthesis from amino acids was stimulated by polyamines, but that from aminoacyl-tRNAs was not stimulated by polyamines.


Infectious complications of burns casualties during the Yom-Kippur War. During the October 1973 military conflict, 41 burned patients hospitalized at the Sheba Medical Center were closely followed up. All the patients who had burns occupying 20% or more of the body surface developed wound infections. Pseudomonas aeruginosa was the major pathogen isolated. Most infections occurred during the second week following the injury. Serial cultures revealed that only the isolation of Proteus species and P. aeruginosa from wounds could predict an infection caused by those microorganisms. During treatment with gentamicin and carbenicillin a marked increase in carbenicillin-resistant P. aeruginosa and gentamicin-resistant Klebsiella strains was noted. Cross-infections with carbenicillin-resistant P. aeruginosa was not a major cause in the development of resistant strains.


A study of behavior and body type in troubled youth. This study explored the relationship of selected physiological and morphological variables of male youth experiencing persistent and inappropriate behaviors in the home, school, and/or community and a control group. The results tend to support differences between the groups in body type, percent of body fat, and strength.


Mini-groups for school children: preventive self-help groups that teach physicians. School Health Program mini-groups were initiated with a two-fold purpose: (1) to create an environment in which a young person is able to explore a self-identified concern in a group setting, and (2) to provide one of several school-based learning experiences for pediatric residents. Drawing on past successes, the program will now channel its efforts toward developing evaluative research methodology and expanding the mini-group experience to include trainees from other disciplines concerned with the health, learning and behavior of children.