Detection of hemagglutinins in cultures of squirrel monkey intestinal trichomonads.

Intestinal trichomonads are very common inhabitants of captive squirrel monkeys. In evaluating the potential pathogenicity of these organisms, we encountered hitherto unknown hemagglutinins in their culture fluids. The cytopathic effect associated with a number of the isolates resembled that caused by vacuolating viruses. We have ruled out conventional viruses as the cause of the cytopathic effect and as the source of the hemagglutinin. The agglutinin has some of the basic characteristics of lectins. Parallel experiments demonstrated agglutination of erythrocytes from squirrel monkeys, humans, dogs, cats, guinea pigs, and horses, with the first two types being the most sensitive. Relatively less agglutination was seen with rat erythrocytes. Agglutination of sheep, rabbit, chicken, and bovine erythrocytes was virtually absent.     

Tuning properties of auditory cortex cells in the awake squirrel monkey

Summary Pure tone bursts elicited in primary auditory cortex (AI) cells of the awake squirrel monkey a wide range of response patterns which consisted of one or more excitatory or inhibitory temporal response components. In almost 60% of these cells, response patterns were frequency and/or intensity dependent. Response components such as early and late onset excitation, offset excitation and on-off excitation; as well as tonic excitation or inhibition often varied independently with changes in these stimulus parameters. Individual cells were therefore considered as multiple bandpass filters, and each discrete response component was analyzed separately for its tuning properties. A correlation between best frequencies of the various excitatory components (BEF), and between BEFs and best frequencies of inhibitory components (BIF), in cells which responded with more than one discrete response component, disclosed a significantly higher correlation between BEF/BIF pairs compared with BEF/BEF pairs, presumably reflecting certain lateral inhibition like processes. Applying Q_10dB factor, and Hf-Lf bandwidth at 10 dB above threshold, as measures of the sharpness of response areas, revealed that approximately 65% of all response areas could be defined as narrow by either one of these 2 measures, with no distinction, in that regard, between excitatory and inhibitory components. The average response bandwidths of the narrowly and the broadly tuned components, at 10 dB above threshold, were 0.4±0.18 and 1.42±0.68 octaves respectively. A comparison with the medial geniculate body (MGB) of the squirrel monkey, applying the Hf-Lf measure of sharpness of tuning, showed a significantly higher proportion of narrow response areas in the AI. Narrow response areas in both these regions were equally narrow, whereas the broad response areas of MGB cells were significantly broader. These results suggest a sharpening of response areas throughout the geniculo-cortical transformation.     

Basic properties of Tritrichomonas mobilensis hemagglutinin.

Tritrichomonas mobilensis is a recently described enteric protozoon of squirrel monkeys. An earlier report identified one of the metabolic products of this organism as a lectinlike hemagglutinin. Its further properties were determined in this study. Culture supernatants of T. mobilensis FP4190 were concentrated by ultrafiltration through a membrane with 100,000-molecular-weight cutoff. High titers of agglutinin against human erythrocytes were obtained. Incubation at 70 degrees C for 15 min resulted in complete inactivation. Exposure to 56 degrees C for 30 min was without effect, and only partial loss of activity was obtained during incubation for up to 18 h. Maintenance at pH 4 to 9 for 4 h at room temperature had no deleterious effect. Apparent degradation of the hemagglutinin was achieved by 18 h of contact with proteinase K, but trypsin and collagenase were essentially ineffective. Papain increased the sensitivity of the test. In the presence of this enzyme hemagglutinin was demonstrated also in cultures of Tritrichomonas foetus and Tritrichomonas augusta but not in those of Pentatrichomonas hominis or Trichomonas vaginalis.     

Diagnosis of pregnancy in the squirrel monkey

Diagnostic pregnancy assessments have been carried out in 18 squirrel monkey females using Delfs' method for chorionic gonadotropin bioassay palpatory, x-ray and other auxiliary techniques. Out of the 24 bioassay tests performed, 11 were positive (one of them weakly positive) and 13 negative. These results were confirmed by the other parallel measures, except in two cases of possible false positive reactions. No false negative results were noted. The implications of the results are discussed in terms of the sensitivity and reliability of the bioassay in the early diagnosis of pregnancy in the squirrel monkey.     

Olfactory recognition in the infant squirrel monkey

Infant squirrel monkeys were reared with surrogates and tested at 4, 8, and 12 weeks of age on their preferences for odors and colors of the surrogates. Surrogates in the rearing color that contained an infant's own odor were preferred to clean ones of the same color. Surrogates in the rearing color that did not contain an animal's scent were generally not preferred to different colored surrogates that were also clean. The results suggest that olfaction plays an important role in the development of social attachment in the young squirrel monkey and is more effective than at least one source of visual information.     

Cerebral representation of vocalization in the squirrel monkey

Summary Specific vocalization types following electrical stimulation of 5940 electrode positions are studied in 39 squirrel monkeys. Except cerebellum, caudal medulla, and a few cortical areas, the sites of stimulation were distributed throughout the brain. Each vocalization elicited was tested for reproducibility at the site of stimulation and in homologue structures. All vocalizations were analyzed spectrographically and then classified for eight fundamental vocalization types.The cerebral distribution of two call types forms continuous systems extending from midbrain via diencephalon into forebrain; the remaining call types are represented in several separate areas not continuous with each other. In medulla and pons the responsive substrates for vocalization follow the course of the spinothalamic tract; in midbrain they lie within the periaqueductal gray, lateral tegmentum, and lemniscus medialis; in diencephalon they are found in the hypothalamus and midline thalamus; in forebrain, finally they are distributed over amygdala, stria terminalis, substantia innominata, preoptic region, septum, rostral hippocampus, posteromedial orbital cortex, cingulate gyrus, and rostroventral temporal cortex. Hence a close relation between limbic system and vocalization producing substrates emerges.Among the brain structures yielding vocalization the mesencephalic periaqueductal gray is assumed to be the region where the electrical stimulus interferes most directly with specific vocalization mechanisms.Besides the anatomical site of stimulation the set of stimulus parameters is important for the elicitation of vocalizations. Relations between amplitude, frequency, and duration of impulses on the one hand and type, loudness, rhythm, duration, and latency of vocalization on the other hand were tested. The influence of the stimulus set on the reaction parameters depends also on the relative position of the electrode within the effective structure. Proper manipulation of stimulus parameters often results in the disintegration of a complex stimulus response into single components.Abbreviations a Nucl. accumbens - aa Area anterior amygdalae - ab Nucl. basalis amygdalae - ac Nucl. centralis amygdalae - al Nucl. lateralis amygdalae - am Nucl. medialis amygdalae - an Nucl. anterior thalami - anl Ansa lenticularis - aq Substantia grisea centralis - bc Brachium conjunctivum - ca Caudatum - cc Corpus callosum - cen Nucl. centralis superior (Bechterew) - cent Centrum medianum - ci Capsula interna - cin Cingulum - cl Claustrum - coa Commissura anterior - coli Colliculus inferior - cols Colliculus superior - cr Corpus restiforme - csp Tr. corticospinalis - db Fasc. diagonalis Brocae - dbc Decussatio brachii conjunctivi - f Fornix - gc Gyrus cinguli - gl Corpus geniculatum laterale - gm Corpus geniculatum mediale - gr Gyrus rectus - gs Gyrus subcallosus - h Campus Foreli - ha Nucl. habenularis - hi Tr. habenulointerpeduncularis - hip Hippocampus - hya Area hypothalamica anterior - hyp Area hypothalamica posterior - hyv Area hypothalamica ventralis - in Nucl. interpeduncularis - lap Nucl. lateralis posterior thalami - lav Nucl. lateralis ventralis thalami - le Lemniscus lateralis - lem Lemniscus medialis - lm Fasc. longitudinalis medialis - m Corpus mamillare - md Nucl. medialis dorsalis thalami - mt Tr mamillothalamicus - nst Nucl. striae terminalis - oi Nucl. olivaris inferior - ol Fasc. olfactorius (Zuckerkandl) - os Nucl. olivaris superior - p Pedunculus cerebri - pmc Brachium pontis - po Griseum pontis - pp Nucl. praepositus hypoglossi - pro Area praeoptica - pu Nucl. pulvinaris thalami - put Putamen - re Formatio reticularis tegmenti - rep Nucl. reticularis tegmenti pontis - rl Nucl. reticularis lateralis myelencephali - rub Nucl. ruber - s Septum - sm Stria medullaris - sn Substantia nigra - st Stria terminalis - sto Stria olfactoria lateralis - tec Tr. tegmentalis centralis - trz Corpus trapezoides - va Nucl. ventralis anterior - vpl Nucl. ventralis posterolaterali thalami - vpm Nucl. ventralis posteromedialis thalami - zi Zona incerta - II Tr. options - IICh Chiasma nervorum opticorum - III N. oculomotorius Nucl. nervi oculomotorii - IV N. and Nucl. nervi trochlearis - VI N. abducens - VII N. facialis - VIII N. acusticus - IX N. glossopharyngeus     

The monoaminergic innervation of the amygdala in the squirrel monkey: an immunohistochemical study

The monoaminergic innervation of the amygdala of the squirrel monkey (Saimiri sciureus) was studied by using immunohistochemical methods with primary antisera raised against serotonin, and the catecholamine synthesizing enzymes tyrosine hydroxylase, dopamine-beta-hydroxylase and phenylethanolamine-N-methyltransferase. Serotonin was widely distributed within the amygdala including profuse terminal labeling in central, basolateral and cortical nuclear groups. The accessory basal and medial nuclei were the only two areas receiving relatively poor serotoninergic innervation. Tyrosine hydroxylase was more discretely distributed, with very dense to moderate terminal labeling in central, basal and lateral nuclei, but only scant labeling within accessory basal and corticomedial nuclei, except at the cortical transitional area where dense terminal labeling was noted. Dopamine-beta-hydroxylase immunoreactivity was moderate in central and corticomedial nuclei, but comparatively light in other nuclear groups. Phenylethanolamine-N-methyltransferase was only sparsely distributed in the amygdala. The findings of the present study reveal that the monoaminergic innervation of the primate amygdala is similar to that reported in rodents, although some conspicuous exceptions do exist. Whereas the noradrenergic and serotoninergic neuronal systems ramify profusely within the amygdala, the dopaminergic system appears to be more discretely and topographically organized.     

Calretinin immunoreactivity in the thalamus of the squirrel monkey

The distribution of the calcium-binding protein, calretinin, in the thalamus of the squirrel monkey (Saimiri sciureus) was studied with immunohistochemical methods. Calretinin was found to be heterogeneously distributed in the primate thalamus and to occur only in specific neuronal populations of certain thalamic nuclei. Neuronal cells and fibers in midline nuclei and their dorsolateral extension, which includes the parataenial and central superior lateral nuclei, displayed the most intense calretinin immunoreactivity. The immunoreactivity for cells and fibers in the intralaminar nuclei was moderate rostrally but very weak caudally. The centre médian nucleus, together with the medial habenular nucleus, were virtually devoid of calretinin immunostaining. The mediodorsal nucleus displayed a markedly heterogeneous staining, with numerous clusters of labeled cells and fibers in its central parvicellular part. Cell and fiber immunoreactivity ranged from moderate to high in the nuclei of the anterior and lateral groups, but was very weak in the nuclei of the ventral and posterior groups. There was a small to moderate number of heterogeneously distributed calretinin-immunoreactive cells and fibers in the lateral and medial geniculate bodies, as well as in the reticular nucleus. The present study provides the first evidence for the existence of calretinin in primate thalamus, where this protein is distributed according to a highly heterogeneous pattern. This specific pattern of distribution suggests that calretinin may play a role that is complementary to those of the other calcium-binding proteins parvalbumin and calbindin D-28k in the thalamus of primates.     

Circadian control of thermoregulation in the squirrel monkey, Saimiri sciureus.

The characteristics and control of the circadian rhythms of core body temperature (colonic) and skin temperature (tail) were studied in chair-acclimatized squirrel monkeys (Saimiri sciureus). When animals were entrained to a light-dark cycle (12 h 600 lx; 12 h less than 1 lx) these two temperatures displayed prominent, reproducible, tightly coupled circadian rhythms. In contsant light of 600 lx, where no other effective circadian time cues were present, both temperature rhythms persisted with free-running periods. Within each animal, however, these rhythms were not as tightly coupled to one another as in LD. On occasion colonic and tail temperature rhythms free-ran with different circadian periods and some animals demonstrated "splitting" of the colonic temperature rhythm, with the colonic temperature rhythm displaying a bimodal pattern. These results suggest that the circadian rhythm of body temperature in primates is under the control of more than one potentially independent circadian oscillator.     

Monoamine-containing cell bodies in the squirrel monkey brain

Fifteen catecholamine-containing cell groups and eight indoleamine-containing cell groups are present in the brain of the squirrel monkey. Most of the catecholamine-containing cell groups (12) are similar to catecholamine-containing cell groups previously described in the rat. However, three catecholamine-containing cell groups not previously noted are found in the squirrel monkey brain. The indoleamine-containing cell groups are found within, or adjacent to, the raphe nuclei. Differences between the localization of indoleamine-containing cell bodies in the brain of the rat and the squirrel monkey are minor.     

Coxsackievirus B4 nephritis in the squirrel monkey

Seventeen squirrel monkeys (Saimiri sciureus) were experimentally infected with Coxsackievirus B4, and the kidneys, as well as other organs, were studied for pathological changes induced by the virus. Seven (41%) of these monkeys developed renal lesions--interstitial and glomerular. The Coxsackievirus was identified in 4 of these 7 monkeys (by isolation from the renal tissue in 2, by immunofluorescence staining of viral antigen in 1, and by electron microscopic finding of viral particles in 1). The renal lesions produced by Coxsackieviral infection described in this report resemble those seen in renal disease in man. These findings support the concept that viruses can produce glomerular and interstitial renal disease. This report also describes a good animal model for the study of viral disease of the kidney.     

Brain stimulation-induced changes of phonation in the squirrel monkey

Summary In 11 squirrel monkeys (Saimiri sciureus), the brain stem was systematically explored with electrical brain stimulation for sites affecting the acoustic structure of ongoing vocalization. Vocalization was elicited by electrical stimulation of different brain structures. A severe deterioration of the acoustical structure of vocalization was obtained during stimulation of the caudoventral part of the periaqueductal grey, lateral parabrachial area, corticobulbar tract, nucl. ambiguus and surrounding reticular formation, facial nucleus, hypoglossal nucleus, solitary tract nucleus and along the fibres crossing the midline at the level of the hypoglossal nucleus. It is suggested that these structures are part of, or at least have direct access to, the motor coordination mechanism of phonation. Complete inhibition of phonation was obtained from the raphe and raphe-near reticular formation.Abbreviations Ab nucl ambiguus - APt area praetectalis - BC brachium conjunctivum - BP brachium pontis - Cb cerebellum - CC corpus callosum - Cd nucl. caudatus - Cf nucl. cuneiformis - Cel nucl. centralis lateralis - Cl claustrum - CM centrum medianum - Cn nucl. cuneatus - Co nucl. cochlearis - CoI colliculus inferior - CoS colliculus superior - CP commissura posterior - CPf cortex piriformis - CRf corpus restiforme - CSL nucl. centralis superior lateralis thalami - CT corpus trapezoideum - DBC decussatio brachii conjunctivi - DG nucl. dorsalis tegmenti (Gudden) - DLM decussatio lemnisci medialis - DPy decussatio pyramidum - DR nucl. dorsalis raphae - DV nucl. dorsalis n. vagi - DIV decussatio n. trochlearis - EP epiphysis - FC funiculus cuneatus - FL funiculus lateralis - FLM fasciculus longitudinalis medialis - FRM formatio reticularis myelencephali - FRP formatio reticularis pontis - FRPc formatio reticularis pontis caudalis - FRPo formatio reticularis pontis oralis - FRTM formatio reticularis mesencephali - FV funiculus ventralis - G nucl. gracilis - GC substantia grisea centralis (periaqueductal grey) - GL nucl. geniculatus lateralis - GM nucl. geniculatus medialis - GP globus pallidus - GPM griseum periventriculare mesencephali - GPo griseum pontis - Hip hippocampus - HL nucl. habenularis lateralis - H habenula - IP nucl. interpeduncularis - LC locus coeruleus - LD nucl. lateralis dorsalis thalami - Lim nucl. limitans - LLd nucl. lemnisci lateralis, pars dorsalis - LLv nucl. lemnisci lateralis, pars ventrali - LM lemniscus medialis - LP nucl. lateralis posterior thalami - MD nucl. medialis dorsalis thalami - MV nucl. motorius n. trigemini - NCS nucl. centralis superior - NCT nucl. trapezoidalis - NMV nucl. mesencephalicus n. trigemini - NR nucl. ruber - NSV nucl. spinalisn. trigemini - NTS nucl. tractus solitarii - NIII nucl. oculomotorius - NIV nucl. trochlearis - NVI nucl. abducens - NVII nucl. facialis - NXII nucl. hypoglossus - OI oliva inferior - OS oliva superior - P nucl. posterior thalami - PbL nucl. parabrachialis lateralis - PbM nucl. parabrachialis medialis - PC depedunculus cerebri - Pd nucl. peripeduncularis - Pg nucl. parabigeminalis - Pp nucl. praepositus - PuI nucl. pulvinaris inferior - PuL nucl. pulvinaris lateralis - PuM nucl. pulvinaris medialis - PuO nucl. pulvinaris oralis - Py tractus pyramidalis - Pv nucl. principalis n. trigemini - R Ab nucl. retroambiguus - RL nucl. reticularis lateralis - RTP nucl. reticularis tegmenti pontis - Sf nucl. subfascicularis - SGD substantia grisea dorsalis - SGV substantia grisea ventralis - SN substantia nigra - ST stria terminalis - St subthalamus - TRM tractus retroflexus (Meynert) - TSc tractus spinocerebellaris - Ves nucl. vestibularis - VL nucl. ventralis lateralis - VPI nucl. ventralis posterior inferior - VPL nucl. ventralis posterior lateralis - VPM nucl. ventralis posterior medialis - VR nucl. ventralis raphae - Zi zona incerta - II tractus opticus - VII n. facialis     

Extraocular motor unit and whole-muscle contractile properties in the squirrel monkey. Summation of forces and fiber morphology

In order to understand the neural control of movement, many investigations have examined the contractile properties of single motor units contracting in isolation, and a great majority of those studies have been done in the cat. Fewer studies, again primarily in the cat, have examined motor units acting in concert in both hind-limb and extraocular muscles. It has been shown, in general, that when individual motor unit forces are added together they do not always add linearly, which makes our understanding of motor control somewhat more complicated. In addition, complex neuronal firing patterns can yield unexpected force outputs or muscle positions whether those patterns occur naturally or are induced through motoneuron stimulation. The current investigation extends these findings of nonlinearity to the primate extraocular system. In studies of the squirrel monkey lateral rectus muscle and its motor units, we show that individual units lose an average of 45% of their force output when they fire in concert with a small number of other motor units. Also, when individual motor units are stimulated at a constant rate of 100 Hz, the force output is most often dramatically different if that constant 100-Hz stimulation is preceded by brief (25 ms), high-frequency stimulation burst or pulse, as occurs during saccades. The force at 100 Hz is usually significantly higher than when no pulse is delivered. However, we now show that an identical stimulation pattern applied to a number of motor units simultaneously does not always yield these force differences. These "nonlinearities" are addressed in terms of the complex muscle architecture that we show in the squirrel monkey lateral rectus muscle. Muscle fibers do not always run in parallel from tendon to tendon. Instead, they may branch or attach to each other laterally or end to end, serially.     

Hormonal responses accompanying fear and agitation in the squirrel monkey

The adrenocortical and gonadal responses of 14 male monkeys were evaluated during four experimental conditions in order to evaluate the influence of social interactions on endocrine responsiveness. Plasma hormone levels were determined during the establishment of social relations, after 60-min exposures to a novel environment, after 60-min exposures to a snake, and 60 min after ACTH administration. Both adrenal and gonadal secretion changed significantly during the first day after social relations were established, although only dominant males showed increases in testosterone, whereas cortisol levels rose in all subjects. Increases in cortisol, but not testosterone, were also observed following exposure to novelty or a snake. The presence of a social partner reduced signs of behavioral disturbance during these test conditions, although the adrenal responses were equivalent or greater than when tested alone. This finding qualifies earlier research which indicated that social support was beneficial for reducing stress when squirrel monkeys were tested in larger groups in their home environment.     

Sleep-wake stages during the subjective night of the squirrel monkey

The study of the circadian sleep-wake cycle is beset by unique technical challenges. Continuous polygraphic recordings are necessary to characterize circadian phenomena; however, the traditional method of recording sleep at high (15 mm/sec) chart speed is impractical for continuous animal studies that may last several weeks at a stretch. A system to determine four sleep-wake stages (awake, transitional, non-REM, REM) from low chart speed (1.5 mm/sec) recordings was developed and validated by direct behavioral observation using four adult male squirrel monkeys prepared for chronic recording of EEG, EOG and EMG. The polygraphic stages "transitional," non-REM and REM were highly correlated with behavioral observations of sleep, although individual sleep stages could not be resolved by behavioral parameters alone.     

The effect of insulin deficiency, hypothyroidism, and hypertension on atherosclerosis in the squirrel monkey

Squirrel monkeys with induced insulin deficiency, hypothroidism, and hypertension, as well as controls were fed a diet containing 1 mg of cholesterol per calorie for over 3 years. The hypothyroid and insulin-deficient monkeys had significantly greater concentrations of serum cholesterol and β-lipoprotein than did the controls, while the controls and hypertensive monkeys did not differ in these regards.