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Unit recordings were performed in the caudate nucleus of awake macaques. Animals were maintained in a restraining chair and had been trained to perform various types of elaborate movements to obtain food-reward. Three types of movement were studied: (a) natural, large gestures of grasping solid food (peanut) from a tray and bringing it to the mouth; (b) small amplitude lever-pressing movements for fluid reward (fruit juice), mainly involving distal segments (fingers, wrist); (c) same as (b), but involving essentially proximal musculature, and consisting of an ample isotonic pulling with arm and shoulder. Units were recorded before and during each of the preceding types of movements (but in different animals). Results indicate that: (1) caudate cells were encountered in all 3 cases which were accelerated during different stages of the movement; (2) more cells were activated in situations (a) and (b) than (c); (3) very few cells displayed inhibition instead of excitation; (4) among cells modified during movement, very few were also accelerated through passive flexions or extensions of the forelimb; (5) some caudate cells were also clearly activated through various visual or auditory intercurrent stimuli, probably arousing the animal's attention.

1. 1. Secretory proteins from the salivary glands of Macaca irus and Cercopithecus aethiops were obtained by the tissue culture technique. 2. 2. Data from isoelectric focusing, gel filtration and immunodiffusion showed extensive similarities between the individual glands of the two species. 3. 3. Immunological identity was present between the three main protein components of submandibular tissue from M. irus and C. aethiops, but the main components of the submandibular glands were not identical with the corresponding sublingual components. One submandibular component was common to the parotid gland secretion.

Indirect hemagglutinating (IHA) antibody responses to Herpesvirus hominis types 1 and 2 (HVH-1 and HVH-2) were compared to complement-fixing and neutralizing antibody responses in immunized laboratory animals (rabbits, guinea pigs, and hamsters) and in natural infections of man. With the immunized animals, type specificity was seen only in the IHA test and only with antisera produced in hamsters and in the rabbits immunized with HVH-2. In human nongenital infections (considered to be caused predominately by HVH-1), IHA and neutralizing antibodies developed at about the same rate and reached approximately the same levels for HVH-1 and HVH-2. IHA titers tended to be higher than neutralizing antibody titers for both virus types. In genital infections (considered to be caused predominately by HVH-2), there was a rapid IHA antibody response to HVH-2, and the early HVH-2 antibody demonstrable by IHA, but not by neutralization tests, was found to be immunoglobulin M in nature. In genital infections, IHA titers for HVH-2 were markedly higher than neutralization titers, but there was no pronounced difference in neutralizing the IHA antibody titers for HVH-1. Several patients with genital infections fialed to develop IHA antibody for HVH-1. The IHA test possessed no greater sensitivity than did complement fixation or neutralization tests for serodiagnosis of HVH infections. Despite the fact that a number of patients with genital infections produced IHA antibody only for HVH-2, the test was no more effective than the neutralization test in providing a type-specific serodiagnosis of infection, due largely to the fact that the rapid IHA antibody response to HVH-2 prevented demonstration of a further, significant antibody titer increase in a number of cases.

—Evidence is presented for the presence of two acidic metabolites of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the sympathetic ganglia of some mammalian species other than ruminants. In the pig, electrical stimulation of the preganglionic nerves to the superior cervical ganglion results in a mean increase of 78 per cent in the concentration of HVA and a mean increase of 372 per cent in the concentration of DOPAC in this sympathetic ganglion. These results can be interpreted as further evidence for the involvement of dopamine in transmission at sympathetic ganglia.

Single unit activity was recorded from the area principalis of the dorsolateral prefrontal cortex during DA in 3 monkeys in order to analyze further the nature of observed differential changes in relation to the different positions of the choice keys (directional selectivity). Out of 354 related units obtained from 170 penetrations, 182 showed directional selectivity. A total of 111 directionally selective units were investigated in sufficient detail to determine whether the observed directional selectivity was related to the absolute or to the relative position of the choice keys. Twenty of these 111 units showed directional selectivity during the delay period and all of these units showed clear dependence on the relations between choice keys. For the remaining units, whose directional selectivity became apparent only after the choice keys were illuminated, dependence on relative factors was less marked. All units showed some dependence on the location of the choice keys, independent of the relations between choice keys.

Six monkeys fed a cariogenic diet for more than 3 yr were divided into two groups. Plaque was removed before the experiment and thereafter at weekly intervals. Throughout the experimental period of 12 weeks, the animals were fed daily with a mixture of Complan and hard-boiled egg by stomach tube. For the first 4 weeks, no food was given orally. During the next 4 weeks, one group was given invert sugar by mouth and the other casein, five times daily. For the final 4 weeks, those which received invert sugar were given casein and vice-versa. Plaque formed in all animals throughout the experimental period. Particularly heavy deposits of calculus were observed in animals fed casein. Plaque formed during tube feeding and also during the casein regimen had little ability to form acid. The carbohydrate content of plaque declined, but calcium and phosphorus levels increased, when the animals received no food by mouth or ingested casein orally. Feeding invert sugar had the opposite effects. The population of yeasts and lactobacilli declined markedly during tube feeding. The numbers of both groups increased more rapidly when invert sugar was fed. These results show that diet influences the composition of plaque and suggest that plaque, which has a low carbohydrate, a high calcium and phosphorus content, and little ability to lower the pH of sugar solutions, is unlikely to be cariogenic.

1 The reaction of tritiated propylbenzilylcholine mustard ([3H]-PrBCM; N-2′-chloroethyl-N-[2″,3″-3H2] -propyl-2-aminoethylbenzilate) with homogenates of mammalian brain has been studied. 2 The uptake can be divided into an atropine-sensitive component of fixed capacity (380 pmol/g protein in the rat) and an atropine-insensitive part. 3 The atropine-sensitive portion is identified as muscarinic receptor by its insensitivity to nicotinic antagonists and anticholinesterases and its sensitivity to a range of muscarinic antagonists. 4 The uptake of [3H]-PrBCM is also inhibited by muscarinic agonists and there is reasonable quantitative agreement between the affinities of agonists estimated in this way and in intact tissues by physiological responses. 5 The fraction of [3H]-PrBCM uptake inhibited by muscarinic antagonists and agonists is the same. 6 The amount of receptor found in six mammalian species was inversely related to the size of the brain, but the rates of alkylation and the sensitivity to atropine were not dissimilar.

The maternal peripheral plasma levels of oestrone (E1)*, oestradiol-17β (E2) and progesterone (P) were determined by RIA during pregnancy in 8 rhesus monkeys (Macaca mulatta). Of special interest were the time courses and the inter-relationships of these steroids during the first month of pregnancy and during the pre- and post-parturient periods. A significant increase in the plasma levels of E1 and E2 occurred at the end of the fertile cycle and lasted for several days and again during the last week before parturition. The plasma levels of E1 and E2 fell dramatically after parturition and remained low during the immediate post-partum period. Two surges in the progesterone levels in plasma occurred at the end of the third week of the fertile cycle and between day 34 and 46 after the onset of menstruation. The progesterone levels in plasma during the remaining gestational period varied widely but a significant increase was found during the days before parturition. A decrease in the plasma levels of P was observed after parturition but the levels of P did not reach follicular phase levels during the post-partum period studied. The possibility of oestrogen secretion from follicles stimulated by chorionic gonadotrophins is discussed as well as the release of prostaglandins by oestrogen before parturition.

Visual discrimination of several types of stimuli were trained to each hemisphere of split-brain monkeys. Stimuli that differed only in orientation and that were spatially redundant were learned in fewer trials by the left hemisphere than by the right. Other stimuli, such as bilaterally symmetrical patterns, up-down mirror images, or photographs of monkeys' faces were learned, on the average, equally easily by either hemisphere. These preliminary results suggest that monkeys may exhibit some degree of cerebral dominance.

Rhesus monkeys were fed a high-fat diet containing either 0, 43, or 129 µg/kcal of cholesterol for 18 months. In the monkeys on the cholesterol-supplemented diets, changes in plasma cholesterol remained within the range found in monkeys fed the cholesterol-free diet. Monkeys on the cholesterol-supplemented diets were compared with monkeys given no dietary cholesterol with range-matched plasma cholesterol; intimal thickness of the aorta and branch arteries, distribution of lipoprotein cholesterol, and tissue content of cholesterol in aorta and liver were considered. The monkeys on the cholesterol-supplemented diets showed intimal thickening with more sudanophilia and increased aortic cholesterol, a decrease in plasma high-density lipoprotein cholesterol, and an increase in low-density lipoprotein cholesterol, and the monkeys fed the higher amount of dietary cholesterol showed an increase in hepatic cholesterol. No null point for the effect of dietary cholesterol on arterial intima was found even at an intake level far below that conventionally used for the induction of experimental atherosclerosis in the nonhuman primate. The intimal changes found in response to very low cholesterol intake imply that subtle qualitative alterations in lipoproteins are of critical importance to our understanding of lesion induction.

Summary Reaching with the ipsilateral and contralateral hand in the light and dark was studied in four rhesus monkeys with unilateral posterior parietal ablations. It was found that reaching in the light was only impaired in the contralateral hand, with gross and predominantly medial misreaching. In the dark, reaching with the contralateral hand was even more impaired than in the light. Reaching with the ipsilateral hand in the dark was also impaired but to a much lesser degree and not as consistently as with the contralateral hand. No significant tendency towards medial misreaching with the contralateral hand in the dark could be found, and a predominance of lateral errors was observed for the ipsilateral hand in the dark. The results indicate that the disorder of reaching found after unilateral posterior parietal ablations in monkeys can not be explained as a disturbance of visual orientation. The findings suggest the presence of a disorder of visuomotor coordination in addition to a non-specific spatial disturbance in the dark and a contralateral somatosensory defect.

The morphology of the inferior olivary complex was determined in the rhesus monkey (Macaca mulatta). The position, configuration, and relations of each of its components were ascertained in serial transverse sections extending from caudal through rostral poles of the complex. The medial accessory nucleus was divided into seven cell groups (labeled a through g). The principal nucleus consisted of well-developed dorsal, ventral, and lateral lamellae and a criterion was established for distinguishing the boundaries of each. This distinction was based upon the pattern of invagination that developed in the principal nucleus in progressing rostrally from its caudal pole. The dorsal and lateral lamellae each presented a characteristic pattern of major invaginations, while the ventral lamella did not. Finally, a detailed comparison was made of the inferior olivary complex of the monkey with that of the cat as determined by other investigators. It was shown that the medial and dorsal accessory nuclei of the two species appeared similar and that the major difference between these species concerns the principal nucleus.

The inferior olivary nuclear complex is generally considered to be the major source of climbing fibers to the cerebellum (Bell and Dow, '67). To test the validity of this statement, experiments using monkeys were designed in which the olivocerebellar fibers were transected in their course through the medulla to the contralateral hemicerebellum. After allowing for anterograde degeneration of these transected fibers, the cerebellum of each monkey was stained and examined for the presence and condition of climbing fibers. In each monkey olivocerebellar fibers were transected at one of three sites: (1) within the right inferior olivary nucleus in one rhesus monkey, (2) at the decussation of the olivocerebellar fibers, within the region of the raphe, in five monkeys and (3) in the left parasagittal plane, just lateral to the inferior olivary nucleus, in one monkey. No noticeable reduction was found in the number of silver stained climbing fibers associated with the Purkinje cells of each hemicerebellum after these lesions. None of the monkeys exhibited durable, specific cerebellar signs. On the basis of the histological evidence obtained from the above experiments, it is concluded that the inferior olivary complex is not the major source of climbing fibers to the cerebellum. Climbing fibers were readily identified in each of the sections examined. However, silver-stained climbing fibers were not associated with many Purkinje cells in every one of these sections. There were 1.7 times more Purkinje cells without climbing fibers than those with climbing fibers. This ratio of 1.7 to 1 characterized normal cerebella as well as both hemispheres of the cerebella of the cerebella of the experimental monkeys.

Chromosomal evolution was examined in a long-term cell culture derived from Macaca mulatta eye tissue. In addition to the ‘marked’ chromosome that characterizes the rhesus karyotype, other chromosomes that may have originated from it by inversions and translocations were identified at each subculture sampled. Our observations do not warrant the conclusion that all the achromatically distinguished chromosomes observed were ‘marked’ rather than ‘marked’ chromosomes; some, however, resembled the ‘marked’ chromosomes found in Aotus and Cercopithecus.

It has been possible to demonstrate a direct relationship between number of sporozoites in an inoculum and the number of subsequent relapses in experimental infections with Plasmodium cynomolgi. The reduction in Sporozoite numbers was accomplished through the use of two techniques; (1) X-irradiation and (2) volumetric dilution. The authors conclude that these observations tend to support a concept of latency as an explanation for relapse and delayed patency in malaria. It is difficult to reconcile these results with the generally accepted concept of a continuous cycle of liver schizogony in relapsing malarias.

Epithelial proliferation of various regions of macaque gingival epithelium, as measured by uptake of locally injected H3-thymidine, showed regional differences which could be explained in part by the size and nature of the inflammatory infiltrate invariably found in gingival biopsies. The proliferative activity of oral sulcular epithelium was greater than that of oral epithelium and was negatively correlated with the size of the area of infiltrated connective tissue. On the other hand labelling of oral epithelium was positively correlated with size of infiltrate, the effect decreasing with distance of the epithelium from the infiltrate

Cardiopep is an acronym for cardioactive polypeptide. It is a newly isolated fraction of bee venom with an estimated molecular weight of 1940. The cardiovascular effects of cardiopep have been studied in a series of 30 isolated perfused Langendorff heart preparations, and in 12 intact animals. When injected into the coronary circulation of the perfused heart, cardiopep produces a 50 ± 10 per cent increase in rate, a 150 ± 50 per cent increase in force of contraction and no change in coronary vascular resistance. These effects lasted for the duration of the experiment. In those hearts in which intrinsic arrhythmias are present, a dose of 0·2 mg of cardiopep produced an immediate restoration of normal cardiac rhythm in addition to the effects on rate and force. In the intact monkey preparation, this same dose of cardiopep produces an increase in heart rate, aortic blood flow and right ventricular force. There are no significant changes in arterial blood pressure, central venous pressure or cortical activity. In addition cardiopep appears to be relatively nontoxic ( LD 50 = 15 mg/kg ) when compared to whole bee venom ( LD 50 = 3·5 mg/kg ). It would appear from these studies that cardiopep is a potent, nontoxic beta-adrenergic-like stimulant not entirely blocked by propranolol and possessing definite anti-arrhythmic properties.

6 protein-malnourished rhesus monkeys were nutritionally rehabilitated by placing them on diets high in protein content. At 60 and 180 days following the initiation of the rehabilitation program, experimental animals and 4 high-protein dietary controls were tested on a preference task designed to determine reactions to foods containing differing quantities of protein and to novel stimuli. Each S was presented a choice of diets containing 2%, 3.5%, or 25% protein, as well as non-food objects. The results indicated that the aversion to novel stimuli (neophobia) and the preference for high-protein food previously reported in protein-malnourished monkeys did not persist following 180 days of rehabilitation. The results suggest that at least part of the behavioral syndrome associated with protein-calorie malnutrition may be improved by 6 mo. of nutritional rehabilitation.

In normothermic rhesus monkeys ( Macaca mulatta ) blood flow to the brain was completely interrupted for 1 h, and then restored for different periods from 45 min to 24 h. Neuronal function was monitored by recording the electrocorticogram (ECoG) and the pyramidal response (PR) to the electrical stimulation of the motor cortex. In addition, cerebral blood flow, intracranial pressure, epicortical pH, blood gases, blood glucose, hematocrit, coagulation times, and serum electrolytes were repeatedly measured. During ischemia, the ECoG was suppressed within 15 sec, and the pyramidal response within a few min. In 11 out of 19 animals the PR and — at survival times of more than 90 min — electrocortical activity returned upon recirculation. In 8 animal recovery of neuronal function did not occur, presumably because of an impaired blood recirculation of the brain. Reduction in post-ischemic blood flow resulted from the combined effect of post-ischemic brain swelling with consequent increased in intracranial pressure, microcirculatory disturbances, and post-ischemic hypotension. In one case the circulatory disturbance was restricted to circumscribed areas causing typical boundary zone lesions in the pallidum and parietal lobe.

Correlative cerebral blood flow (CBF) and vessel diameter studies were performed during graded Paco, change in control monkeys and in monkeys subjected to subarachnoid hemorrhage and internal carotid artery spasm. In the control series CBF increased linearly between Pa CO CO2 values of 30 mm Hg and 60 mm Hg. An increase in Pa CO CO2 from 40 mm Hg to 62 mm Hg produced a mean CBF increase of 74% while a reduction of Pa CO CO2 to 25 mm Hg resulted in a decrease of 40%. Cerebral gray matter was more responsive to Pa CO CO2 change than white matter. Caliber of the larger capacitance vessels did not provide an adequate index of the status of cerebral circulation. In the experimental series both SAH and traumatic internal carotid artery spasm caused a decreased hemodynamic responsiveness to Pa CO CO2 . However, when Pa CO CO2 was raised to 60 to 65 mm Hg, marked increases in cerebral perfusion occurred (breakthrough phenomenon). In general, a poor correlation between CBF and vessel diameter studies was found in the postinsult period. The studies indicated: (1) SAH caused an increase in cerebrovascular resistance and a decrease in CBF, (2) hemodynamic responses to Pa CO CO2 change, although diminished, were not abolished in the acute period after SAH, (3) hypercapnia (Pa CO CO2 > 60 mm Hg) significantly increased cerebral perfusion whether or not vasospasm was alleviated, and (4) the small distal cerebral vessels were more reactive to Pa CO CO2 change and were more intimately associated with regulation of cerebral perfusion.

A total of 359 rhesus monkey teeth and 187 human teeth were studied histologically after cavity preparation and restoration with various materials. It was found that human and monkey teeth do not correlate in all of the established criteria for evaluation of pulp responses. For correlation to be valid, the depth of remaining dentin in monkey teeth should be less than 1.0 mm. Cellular displacement would be considered to be significant only if the monkey teeth are extracted surgically. Both superficial and deep responses can be correlated directly, but the degree of hemorrhage is not significant in evaluating monkey teeth. Although reparative dentin can be correlated, it is formed sooner and in greater amounts in monkey than in human teeth.

Adult rhesus monkeys were infected with five subtypes of Venezuelan equine encephalitis (VEE) virus (IA, IB, IC, ID, and IE). The animals were studied clinically, and samples of serum were taken for determinations of viremia and antibody, leukocyte counts, and biochemical studies. Only monkeys inoculated with VEE subtype IA, IB, or IC developed fever and signs of illness, although high titers of circulating virus were detected in the sera of all animals. Viremia appeared on day 1 after inoculation and disappeared by days 4-6. Most animals, including those infected with subtype ID or IE, were leukopenic. The concentration of glutamic-oxalacetic transaminase in serum was elevated only in monkeys infected with subtype IA or IC. Sera obtained 12 and 47 days after inoculation were tested by serum dilution neutralization and by conventional and "kinetic" HAI tests. The ability of these sera to distinguish among VEE subtypes was somewhat limited; the antigenic differences observed were nevertheless in general agreement with those described by previous workers. This study supports the hypothesis that enzootic VEE subtypes are less pathogenic than subtypes responsible for major epizootics.

Numerous small and medium-sized neuronal perikarya in layers III and IV of the visual cortex display an unusual pattern of ribosomal distribution. Instead of being aggregated in clusters, spirals, rows, and other regular polysomal configurations, the ribosomes, whether free or attached to the endoplasmic reticulum, are randomly dispersed, with no discernible pattern. The endoplasmic reticulum in such cells is reduced to a few (perhaps only one) meandering, broad cisternae, which delimit broad fields of cytoplasmic matrix occupied almost solely by scattered, single ribosomes. The Golgi apparatus is elaborate. Mitochondria are either small and numerous or large and infrequent. The other organelles, including the nucleus and nucleolus, are not remarkable. Axonal terminals synapse in the normal fashion on the surfaces of these cells and their dendrites. Associated with these cells are more numerous intermediate cells in which a few to many polysomal clusters can be found. It is proposed that the neurons with dispersed, single ribosomes are inactive in protein synthesis and that the suspension of such an important metabolic activity is probably temporary. Thus, these cells are considered to be part of a population undergoing cyclic fluctuations in the intensity of protein synthesis that should be correlated with their specific neural behavior.

SummaryThe sensitivity of semipermis-sive cell cultures to SV40 infection can be enhanced by a component of uninfected, simian cells (CV-1) that are permissive for SV40 infection. Enhancement is demonstrated by 10- to 40-fold higher plating efficiency in simian cells, 10- to 30-fold increase in virus production by human cells and 3-fold increase in frequency of transformation in a line of human diploid fibroblasts after inoculation of mixtures containing CV-1 extracts and virus. The enhancer is recovered from cultured cells by a mild extraction procedure and is not sedimented by centrifugation at 20,000g for 1 hr. The active component of the supernate appears to be protein. Incubation of virus with enhancer preparations for 20 min at 23° results in the formation of a complex that is not dissociated by dilution. Although these properties of the SV40 enhancer are similar to those described previously for an enhancer of an enterovirus, the SV40 enhancer differs from the enterovirus enhancer in its host and v...

The present experiment investigates the effect of ablating the main cortical somatosensory projection areas on temperature discrimination in the monkey. Four monkeys were trained preoperatively to discriminate approximately a 1 C difference with the left hand. The S I and S II areas of the right hemisphere were ablated together with the S II area of the left hemisphere, and the subjects were again tested with the same hand. The results revealed that the size of the difference limen was the same after surgery as it had been before and further that the subjects were able to meet the criterion of four consecutive thresholds below 2 C in fewer trials postoperatively than preoperatively. These results, together with others previously reported, suggest that, in the monkey, the cortical region essential to appreciation of fine thermal differences is more widespread than is that required for tactual-kinesthetic discrimination and possibly also that there are differences between monkey and man in the vulnerability of thermal discriminative ability to relatively small cortical lesions.

The 15 fluorocarbons which can be used to propel aerosols have been grouped into 4 classes, depending on their potential to elicit cardiac arrhythmia and depression of myocardial contractility. The most toxic propellant, trichlorofluoromethane (FC 11) produces both forms of cardiotoxicity when inhaled in concentrations of 2.5–5%. The minimal proarrhythmic concentration in the monkey is reduced by i.v. infusion of epinephrine or by production of myocardial ischemia. The combination of the two effects reduced the minimal proarrhythmic concentration to 0.5%. This phenomenon suggests that the hazard of exposure to aerosol propellants is increased in persons with heart disease.

Infant rhesus monkeys whose mothers were fed diets providing 1, 2, or 4 g protein/kg body weight/day during pregnancy were fondled for 5 min before their noon and 1600 hour feedings on 2-3 weekdays weekly. Fourteen were caressed between 10 and 30 days of age; 18 between 41 and 95 days of age. The intake at meals following handling was compared to that for meals when handling was not given. The younger animals' intake was specific to the diet group and treatment. The older animals ate more at the 1600 hour meal than at the noon meal and more at weekday, nonhandled feedings than at weekday, handled or weekend feedings. Differences due to maternal nutritional history were not significant. Infant monkeys subjected to a variety of laboratory anxiety-producing tests during weekdays drank more formula on test days than on tranquil weekends. This effect was ameliorated by preprandial comforting.

The chronic toxicity of caffeine observed with the squirrel monkey appears to be related to the long plasma half-life of caffeine in this species. A half-life of 11 hr was found following the administration of 5 mg/kg compared to 2.4 hr in the rhesus monkey (5 hr or less have previously been reported for the mouse, dog and man). The methylxanthines found in the tissues and urine of the squirrel monkey following caffeine administration were the same as those reported for other species. No difference in the metabolism of caffeine by a squirrel monkey showing a toxic response to 25 mg/kg/day and a monkey tolerating this dose could be determined. The squirrel monkey appears to have a unique deficit in its ability to catabolize caffeine to metabolites which can be effectively excreted.

In rhesus monkeys ( Macaca mulatta ), superovulation has been successfully induced using a combined regimen of PMS, HCG and PG E1 or E2. The ovulation was confirmed by a number of ova recovered either from the tubes or from the uterine flushings at various intervals after ovulation. The time of ovulation in this study under the conditions cited appears to be around 60 hrs after HCG, 36 hrs after PG administration.

The genetic polymorphism of red cell phosphoglycerate kinase was investigated in primates. Five variants of the enzyme were detected.

Three groups, each of eight adult male monkeys were maintained for a little over 1 year on diets containing 20% mustard oil, peanut oil or hydrogenated peanut fat, respectively. Animals of the mustard oil group showed sarcoplasmic vacuolation of right and left ventricular myocardium. Half the number of monkeys also exhibited a variable degree of myocardial fibrosis which involved the subepicardial zone of the right ventricular wall between the tricuspid valve and apical region. That these changes were not the manifestations of a high fat intake per se was shown by the absence of such changes in the hearts of the animals consuming similar amounts of peanut oil or hydrogenated peanut fat. The results indicated the possible hazards of consuming diets rich in mustard oil for prolonged periods, which like rapeseed oil contains high amounts of erucic acid.

2 types of antibody response specific for intrastrain antigenic variants of P. knowlesi can be detected in the serum of M. mulatta . One induces a change in the parasite serotype, the other is parasiticidal. The rate of synthesis of both types of antibodies to new variants increases as the host develops protective immunity and their rate of synthesis relative to one another also changes. Both these effects are possibly important in determining the level of parasitaemia.

The formation of cholesteryl ester in aortic tissue was studied using subcellular fractions from normal and atherosclerotic rabbit and rhesus monkey aortas. The properties of two enzyme systems capable of esterifying 1- 14 C-oleic acid into cholesteryl ester in vitro were investigated, and increased activity was demonstrated for both systems as a result of cholesterol feeding. Microsomal preparations were used to study the ATP, CoA-dependent esterification which involves two enzymes, fatty acyl CoA synthetase and fatty acyl CoA: cholesterol acyltransferase. The properties of both enzymes were investigated, and an increase of about fourfold in activity of the acryltransfrease was demonstrated in aortic microsomes as a result of cholesterol feeding for 3-6 months. Esterification of oleic acid into cholesteryl ester by aortic high-speed supernatant fractions at an acidic pH was also observed; the enzyme system involved did not require cofactors, and its activity greatly increased as a result of cholesterol feeding. Similar increases in the activity of both esterifying enzyme systems were found when normal and atherosclerotic rhesus monkey aortic fractions were compared. p -Chlorophenoxyisobutyrate (CPIB) and 2-methyl-2-[ p -(1, 2, 3, 4-tetrahydro-l-naphthyl)-phenoxy]propionic acid (TPIA) produced inhibition of both cholesterol-esterifying enzyme systems. TPIA was a more effective inhibitor than CPIB on both enzyme systems by at least an order of magnitude. These studies suggest that increased intracellular synthesis of cholesteryl ester by aortic tissue may contribute to its accumulation in atherosclerosis.

A model for the enhancement of the primary humoral immune response of rhesus monkeys to marginal or weakly antigenic vaccines is presented. Our procedure used the complexing of formalin-inactivated Venezuelan equine encephalomyelitis (VEE) virus vaccine with specific, homologous, immune gamma globulin (IgG) at equivalence. Equivalence was determined by combining the concentrated, isotopically labeled ( 3 H) virus with various concentrations of specific Sephadex-fractionated IgG. Enhancement of VEE virus antibody response in monkeys was obtained from preparations containing a marginal concentration of antigen that was complexed at equivalence with homologous IgG as compared with antigen alone. Protection in Swiss mice closely paralleled the antibody response pattern observed in monkeys, since complexes at equivalence provided 30 to 50% greater protection against challenge than antigen alone.

Electron microscopic examination of the lateral geniculate nucleus in monkeys reveals the consistent occurrence of triadic synaptic arrangements where a retinal axon terminal is presynaptic to both a principal cell (P-cell) and a non-axonal portion of an interneuron (I-cell) containing flattened vesicles, which in turn is presynaptic to the same P-cell element. These ‘triads’ are found within glomeruli where the P-cell participates with a dendritic protrusion and the I-cell with a dendritic appendage (type 1 triad), and also outside the glomerulus where the P-cell is represented by its soma or very proximal dendrite (type 2 triad), or the I-cell profile is the soma which again contains synaptic vesicles (type 3 triad). The most parsimonious interpretation of the functional significance of the triadic synapse is to consider it as a device for the inhibitory phasing of the P-cell discharge resulting from the release of I-cell inhibitory transmitter by excitation of the interneuron through the same retinal afferent which causes the initial tonic activity of the P-cell. Further roles of the I-cell are discussed on the basic of a model which considers a random geometry of dendritic (long) and axonal (short) arborizations. The model suggests 3 possible I-cell actions: (1) local inhibition limited to the triadic arrangement; (2) inhibition at a distance through an axonal mechanism; and (3) inhibition at a distance by way of the presynaptic dendrites.

Yaba tumor virus progeny appeared in cynomolgus monkey kidney cells at 24 h postinfection and reached a plateau at 72 h in the first cycle of replication. Viral DNA synthesis was first detected at about 3 h and reached a peak in 18 h. Maximum coating of viral DNA in infected cells occurred at 4 days postinfection. Rapidly labeled RNA was synthesized in the cytoplasm of virus-infected cells. At 6 h postinfection 7 to 10 S RNA was present; this species was present in greater amount at 12 h; at 24 h a truncated peak indicated the presence of 14 to 15 S as well as 7 to 10 S RNA. Hybridization data indicated that the largest peak of messenger RNA synthesis occurred at 11 to 13 h postinfection and a second, slightly smaller, peak occurred at 21 to 23 h.

Extract: Experimentally induced endotoxemia in the rhesus monkey produced a two- to fourfold increase in plasma triglyceride concentration; glucose administration partially prevented this rise. Plasma free fatty acid and phospholipid values were depressed 40–50% of control values whereas cholesterol values were unchanged. Endotoxin-treated monkeys displayed slowed glucose disappearance (K values, 2.2 versus 1.1) and higher levels of sugar in blood when given glucose (72 ± 8 mg/100 ml versus 151 ± 11 mg/100 ml). These studies indicate that endotoxin has a marked effect on the pattern of substrate utilization by the host. Speculation: Alterations in lipid and carbohydrate metabolism affecting substrate utilization of the host may account for many of the clinicopathologic events associated with endotoxemia. Therapeutic measures designed to increase the availability of metabolic fuels for efficient cellular fuel utilization might be of value to patients during endotoxemia.

SummaryEnterovirus field and prototype strains were tested for agglutination using human and African Green Monkey erythrocytes. Only ECHOvirus types 7, 12, and 29 agglutinated monkey erythrocytes; the titers were similar to those obtained with human erythrocytes. Passage of these ECHOviruses in human diploid fibroblast cells caused a reduction in hemagglutination titers of some of the strains. Human and monkey erythrocytes after prior adsorption and elution still retained their receptors for ECHOvirus hemagglutinins. Treatment of ECHOvirus 29 hemagglutinin with trypsin removed combining sites for receptors on monkey erythrocytes but not those on human erythrocytes. No differences in ECHOvirus types 7 and 12 hemagglutinins for human erythrocytes or monkey erythrocytes were detected by chemical treatment of these viruses.

Plasma concentrations of cortisol (F) and growthhormone were determined in samples obtained sequentially at 15 min intervals for 12 h night and 12 h day sessions in juvenile male monkeys (6–9.5 lb.) i

Four new type C viruses were isolated from putatively virus-negative baboon lung, kidney, and testicular cells by cocultivation with several permissive host cell lines. The baboon type C viruses are infectious for cells from various mammalian species, but do not replicate in any baboon cell lines so far tested. These viruses can be distinguished from other major classes of mammalian type C viruses, including previous isolates from primates, but are most closely related to endogenous feline viruses of the RD-114/CCC group. By immunologic criteria, viral host range, and nucleic acid hybridization studies, the baboon type C viruses are highly related to one another and represent a distinct new class of endogenous primate type C viruses.