Characterization of prenatal growth and development in the crab-eating macaque (Macaca fascicularis) by ultrasound

Diagnostic ultrasound is a valuable tool for the examination of various anatomical structures in vivo. Improvements in technology have increased its effectiveness and provided a noninvasive method for the in utero observation of a variety of structural and functional events. Ultrasound is utilized in our laboratory to monitor a variety of studies during embryonic and fetal development. Basic to these evaluations is the ability to assess normal growth and development. The cynomolgus, or crab-eating macaque (Macaca fascicularis), has been observed in utero by ultrasound from early gestation to term. The earliest detection of implantation is by the identification of a developing gestational sac (GS), which may be visualized on gestational day (GD) 14-15. Positive identification of the GS on GD 16-18 and appearance of the embryo, yolk sac, and cardiac motion on GD 21-25 confirms pregnancy. Once the embryo is evident, measurements of the greatest length (GL) may be used to assess normal growth or to aid in the prediction of gestational age. During the fetal period, a variety of growth parameters aid in fetal evaluation. The gender of the fetus can be accurately identified as early as GD 70-75. An assessment of viability and condition can be determined by the observation of embryonic and fetal heart rates and gross body movement.     

Spontaneous hepatitis similar to hepatitis A in African green monkeys

Circulation of a virus similar to human hepatitis A virus by antigenic and some other properties was observed among African green monkeys imported from their natural habitats. In some of the monkeys this virus caused a disease similar to hepatitis A in many features.     

A comparison of thermoregulatory responses in the Japanese macaque (Macca fuscata) and the crab-eating macaque (Macaca irus) during cold exposure.

Thermoregulatory responses in four male adult Japanese macaques and four male adult crab-eating macaques, weighing 6-12 kg and 6.2-8 kg, respectively, were compared at ambient temperatures (Ta) ranging from 5 degrees C to 25 degrees C. The average values +/- S.E. for some physiological measurements made at Ta of 25 degrees C in the Japanese macaque and the crab-eating macaque, respectively, were as follows: resting metabolic rate; 47.6 +/- 5.0 and 42.5 +/- 1.7 W/M2; tissue conductance; 11.9 +/- 0.8 and 8.9 +/- 0.8 W/M2/degrees C; respiratory evaporative heat loss; 4.1 +/- 0.3 and 3.2 +/- 0.5 W/M2; rectal temperature; 38.6 +/- 0.1 and 37.4 +/- 0.2 degrees C; mean skin temperature; 34.0 +/- 0.3 and 31.2 +/- 0.1 degrees C. When Ta was lowered stepwise from 25 degrees C to 20, 15, 10, and 5 degrees C successively, and maintained constant at each temperature level for 1 hr, metabolic heat production graudually increased in both species. Whe Ta was lowered from 10 degrees C to 5 degrees C, the crab-eating macaque did not show further increase in heat production and the result was a loss of thermal equilibrium with rectal temperature continuing to fall. On the other hand, the Japanese macaque maintained thermal balance even at Ta of 5 degrees C. Tissue conductance, which was significantly higher in the Japanese macaque than in the crab-eating macaque at Ta of 5, 15, and 25 degrees C, decreased in both species at Ta was lowered from 25 degrees C to 15 and 5 degrees C. The specific differences in thermo-regulatory responses are considered to be adaptational, relative to the natural habitat of thw two species studied.     

Spontaneous thymoma in a juvenile cynomolgus macaque (Macaca fascicularis)

A single, solid, yellow-white thymic mass was found at necropsy of a two-year-old female cynomolgus macaque from a four-week, repeat-dose toxicity and immunogenicity study. Microscopically, the mass was multilobular and well encapsulated, surrounded by a thick connective tissue capsule, and composed of dense sheets of elongate or spindle-shaped cells and large cystic cavities separated by thick connective tissue stroma. Normal thymus was adjacent to the mass, but it was compressed. Within the mass were abundant interspersed Hassall's corpuscles; individual and small clusters of mature, small lymphocytes; scattered eosinophils; large areas of necrosis; focal mineralization; and cholesterol clefts. An interesting feature was the presence of large multinucleated giant cells, which varied widely in size and nuclear number. Immunohistochemical staining for two lymphocyte markers and two structural proteins confirmed the identity of the neoplastic spindle cells and other cellular components. There was no evidence of vascular invasion or metastasis. Features of the thymoma indicated it was a pre-existing condition and not treatment related.     

Spontaneous extracutaneous systemic mastocytosis in a cynomolgus macaque (Macaca fascicularis)

A uniform cell population of proliferating mast cells with poor cytoplasmic granularity and a few eosinophilic infiltrates was observed in hepatic portal tracts and the cecal submucosa of an adult male cynomolgus macaque (Macaca fascicularis) that was part of a drug safety assessment toxicity study. The proliferating mast cells were positive for Giemsa and toluidine blue staining and had strong immunoreactivity for mast cell tryptase and CD68. Considering size, morphology, immunoreactivity, and distribution of the lesions a benign proliferative disorder of connective tissue mast cells was diagnosed comparable to that seen in indolent systemic mastocytosis in humans, but lacking associated skin lesions. The finding of visceral mast cell proliferation has to be included in the spontaneous background pathology spectrum of cynomolgus macaques used in toxicological studies.     

Spontaneous and experimental hepatitis A in Papio hamadryas]

Data on high susceptibility of Papio hamadryas to HAV are presented. For the first time, P. hamadryas were shown to be able to respond to both natural and experimental infection developing the features typical of hepatitis A: increased aminotransferase activity, virus shedding in feces, production of anti-HAV IgG and IgM, histological liver lesions. An infection lingering for 3-4 months was observed, as well as a case of chronic experimental hepatitis A with relapse in 7 months of the disease. Virological evidence of HAV infection was obtained in both lingering and chronic disease. HAV-PH strain was isolated for the first time and is described at length. It was isolated from a baboon with spontaneous infection which did not differ from that in man by antigenic and morphological features. The virus replicated in continuous African green monkey kidney cell line (AGMK) and was pathogenic for P. hamadryas. The HAV-PH isolate can be used for modelling hepatitis A in P. hamadryas.     

Spontaneous and drug-induced hepatic pathology of the laboratory beagle dog, the cynomolgus macaque and the marmoset

This review focuses on the background hepatic pathology present in three of the most commonly used species in the safety assessment of drugs, namely the beagle dog, the marmoset and the cynomolgus macaque. Both the nonneoplastic and neoplastic pathology are reviewed with a discussion on the potential impact that significant background pathology might have on the interpretation of any drug-induced pathology during subsequent testing. Although specific instances, such as parasitological infection in wild-caught primates can pose problems of interpretation, in general the background pathology in both the dog and the nonhuman primates, is not significantly different from that seen in the liver of laboratory rodents and with experience should not pose significant problems for the experienced pathologist. The relative merits of the primate versus the dog as a choice of second species are also considered in some detail. Although there is an inbuilt prejudice that the primate will more closely mimic subsequent effects that might occur in man in the clinic, insofar as the liver is concerned, there are many instances where the dog has been more representative of human exposure and metabolism and there is little evidence to show that the nonhuman primate is consistently better than dog in predicting human liver toxicity. As with most areas of science, comparative toxicology would dictate that the more information gained, from as wide a range of species as is practical, will give the best assessment for any subsequent problems in the clinic. This pragmatic approach should prove to be more successful than one based entirely upon an assumption, and in many cases the assumption is incorrect, that the primate always predicts human toxicity better than the nonprimate, including the dog.     

Spontaneous pallidal neuronal activity in human dystonia: comparison with Parkinson's disease and normal macaque

Dystonia is a movement disorder defined by sustained muscle contractions, causing twisting and repetitive movements and abnormal postures. To understand the abnormalities in pallidal discharge in dystonia, we have analyzed the spontaneous activity of 453 neurons sampled from the internal or external pallidum (GPi or GPe) of 22 patients with dystonia, 140 neurons from 11 patients with Parkinson's disease (PD), and 157 neurons from two normal non-human primates (NHPs; Macacca mulatta). All recordings were performed without systemic sedation. Mean GPi discharge rate in dystonia was 55.3 +/- 1.3 (SE) Hz. This was significantly lower than in the normal NHPs (82.5 +/-2.5 Hz) and lower than in PD patients (95.2 +/- 2.3 Hz). Mean GPe discharge rate in dystonia (54.0 +/- 1.9 Hz) was lower than in the normal NHPs (69.7 +/- 3.3 Hz) and was indistinguishable from that in PD patients (56.6 +/- 3.5 Hz). Mean GPi discharge rate was inversely correlated with dystonia severity. GPi showed increased oscillatory activity in the 2- to 10-Hz range and increased bursting activity in both dystonia and PD as compared with the normal NHPs. Because the abnormalities in discharge patterns were similar in dystonia compared with PD, we suggest that bursting and oscillatory activity superimposed on a high background discharge rate are associated with parkinsonism, whereas similar bursting and oscillations superimposed on a lower discharge rate are associated with dystonia. Our findings are most consistent with a model of dystonia pathophysiology in which the two striatal cell populations contributing to the direct and indirect intrinsic pathways of the basal ganglia both have increased spontaneous activity.     

Restoration of the immune response by macrophages in mice after administration of immunodepressants

The possibility of restoring the primary immune response in mice immunized with bacteriophage T2 after administration of various immunodepressants (actinomycin D, olivomycin, rifampicin, chloramphenicol, chloroquine, histone F2a, and bacterial lipopolysaccharide) was studied. For this purpose peritoneal macrophages from intact syngeneic donors were transferred simultaneously with injection of the antigen into the recipients following administration of the immunodepressants. The immunodepressive effects of most of the substances studied could be completely compensated in this way. Macrophages can thus be regarded as one of the sites of action of the immunodepressants studied. The results also indicate a role of the macrophages in the induction of the primary immune response to bacteriophage T2 (synthesis of phage-neutralizing antibodies).     

Spontaneous hepatitis in Long-Evans rats. A potential animal model for fulminant hepatitis in man

Spontaneous hepatitis associated with severe jaundice occurred in 90% of an inbred strain of Long-Evans rats. The rapidly progressive syndrome was characterized by abrupt onset, hyperbilirubinemia and increased serum levels of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase, associated with massive and multifocal necrosis of the liver. This strain should provide a useful animal model for analysis of the pathogenesis of fulminant hepatitis in humans.     

The cutaneous cervical plexus nerves of the crab-eating macaque (Macaca fascicularis), eastern grey kangaroo (Macropus giganteus), and koala (Phascolarctos cinereus)

The origin, course and distribution of the cutaneous nerves of the cervical plexus were examined in the crab-eating macaque (4 body-halves), the grey kangaroo (5 body-halves) and koala (3 body-halves). The cutaneous nerves, n. auricularis magnus, nn. supraclaviculares, n. transversus colli, and n. transversus cervicis, were recognized. Cranial and caudal branches were identified in the latter 2 nerves. Some intermediate, relatively small branches were recognized between these main nerves. The n. occipitalis minor was not recognized in all our specimens. Four segmental nerves, C2 to C5, gave rise to all the cutaneous nerves and branches of the cervical plexus described. However, between species there was some variation. In the crab-eating macaque the n. auricularis magnus and n. transversus colli tended to arise from a lower segment than in the grey kangaroo and koala. In the grey kangaroo the nn. supraclaviculares arose from a lower segment than in the crab-eating macaque and koala.     

Spontaneous hepatitis A with a fatal outcome in rhesus monkeys

This is the first report of virologically verified spontaneous hepatitis A in M. rhesus monkeys with severe involvement of the liver leading to the death of the animals. In 21 out of 23 dead monkeys morphological lesions in the liver have been characterized as acute hepatitis. In 6 (26%) animals no other pathological processes were found. In 15 animals hepatitis was combined with other diseases (dysentery, parasitic infestations, coronavirus infection). Antigen of hepatitis A virus was detected by an enzyme immunoassay in the intestinal contents of 8 monkeys and in the livers of 3 of them. Immune electron microscopic studies detected in the intestines some virus particles morphologically and antigenically similar to human hepatitis A virus.     

Refinement of macaque synteny arrangement with respect to the official rheMac2 macaque sequence assembly

We have compared the synteny block organization of the official macaque genome sequence assembly (Jan. 2006; rheMac2) with an independent assembly that used a molecular cytogenetic approach. The mapping of four synteny segments, ranging in size from 4 Mb to 24 Mb, was found to be inconsistent between the two datasets. We specifically investigated these discrepancies by appropriate co-hybridization FISH experiments with validated reference probes located outside the area under study. We found that in the macaque rheMac2 release three synteny segments were wrongly mapped and one segment was incorrectly oriented.     

Dynamic changes in hepatitis C virus genotypes and sequence patterns in plasma donors exposed to reinfection

Sequential serum samples from four plasma donors (designated A, B, C, and D) at a Chinese blood bank with hepatitis C transmission problems were studied from 1994 to 1997. The samples were examined for antibodies to HCV, for HCV viremia by PCR and HCV genotyping. Co- and superinfections were studied by direct sequencing of the 5'-NCR, core, and HVR-1 regions, using low and high genotype-specific primers targeting the HVR-1, and by cloning of selected samples. Genotype changes occurred in all four donors: A (1b-2a-1b), B (1b-2a-2a/1b-1b), C (1b-2a), and D (1b/2a-1b). Donor D was married to donor B. The 1b isolates of donor A could not be sequenced in the HVR-1 due to low-level viremia. Two early 1b isolates from donors B and C showed high HVR-1 similarity. The later 1b isolates from B had changed significantly but were identical to the isolate from donor D. Spouses B and D also shared genotype 2a strains. The 2a isolates from donors A, B/D, and C differed by 8-10 nucleotides in the HVR-1. The frequent changes in genotype and the appearance of homologous isolates from different subjects indicate transmission at the blood bank. These four donors, all identified shortly after infection, developed very few mutations in the HVR-1 and few quasispecies during a period of 6-18 months. Highly specific primers proved to be superior to cloning for identification of minor virus populations. The results indicate nosocomial transmission of more than one strain at the blood bank studied.     

Cerebello-thalamo-cortical projections to the posterior parietal cortex in the macaque monkey

This study reinvestigated the functional neuroanatomy of phonological and visual working memory in humans. Articulatory suppression was used to deprive the human subjects of species-specific verbal strategies in order to make the functional magnetic resonance imaging results more comparable to findings in non-human primates. Both phonological and visual working memory processes activated similar prefronto-parietal networks but were found to be differentially distributed along several cortical structures, in particular along the anterior and posterior parts of the intermediate frontal sulcus. These results suggest that a domain-specific topographical organization of neural working memory mechanisms in the primate brain is conserved in evolution. However, the findings also underline the critical dynamic influence that the additional availability of language may have on working memory processes and their functional implementation in the human brain.     

Somatosensory input to auditory association cortex in the macaque monkey

We investigated the convergence of somatosensory and auditory inputs in within subregions of macaque auditory cortex. Laminar current source density and multiunit activity profiles were sampled with linear array multielectrodes during penetrations of the posterior superior temporal plane in three macaque monkeys. At each recording site, auditory responses to binaural clicks, pure tones, and band-passed noise, all presented by earphones, were compared with somatosensory responses evoked by contralateral median nerve stimulation. Subjects were awake but were not required to discriminate the stimuli. Borders between A1 and surrounding belt regions were identified by mapping best frequency and stimulus preferences and by subsequent histological analysis. Regions immediately caudomedial to A1 had robust somatosensory responses co-represented with auditory responses. In these regions, both somatosensory and auditory response profiles had "feedforward" patterns; initial excitation beginning in Lamina 4 and spreading to extragranular laminae. Auditory and somatosensory responses displayed a high degree of temporal overlap. Anatomical reconstruction indicated that the somatosensory input region includes, but may not be restricted to, the caudomedial auditory association cortex. As was earlier reported for this region, auditory frequency tuning curves were broad and band-passed noise responses were larger than pure tone responses. No somatosensory responses were observed in A1. These findings suggest a potential neural substrate for multisensory integration at an early stage of auditory cortical processing.     

Contralateral cortical projections to the superior colliculus in the macaque monkey

Summary Cortical projections from the contralateral hemisphere to the superior colliculus (SC) were studied in macaque monkey using retrograde transport of the enzyme horseradish peroxidase (HRP). After single or multiple injections of HRP into SC, labelled cells were found contralaterally in layer V of the anterior bank of the arcuate sulcus, the origin of this contralateral projection being confined to the anterior part of Brodmann's area 6. Only a few labelled cells appeared in adjacent area 8. Labelled cells occured in patches, forming bands which were found to run in a ventromedial direction. A similar pattern was seen homotopically in ipsilateral area 6. Thus, this anterior part of area 6 gives rise to a bilateral projection to the SC. The findings emphasize structural differences in a region of the frontal lobe which has been considered functionally uniform as frontal eye field.Supported by Deutsche Forschungsgemeinschaft (SFB 50/C6 and Di 212/2)