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Age determination of common marmosets (Callithrix jacchus) by radiographic examination of skeletal development.

Seventy-four animals were examined radiographically to determine the skeletal development of the common marmoset (Callithrix jacchus) from 6 months of age. Twenty-one epiphyses were examined and five stages of ossification were described for each. The animals were divided into nine groups, according to age, and a table of the stage of ossification and age was produced, which may be used for determining the age of animals of unknown history.

Age Determination by Skeleton

Ontogeny of monooxygenase activities in the marmoset monkey (Callithrix jacchus).

The pre- and postnatal development of monooxygenases in the liver and adrenal gland of marmoset monkeys (Callithrix jacchus) was investigated. Cytochrome P450 was detected in the fetal adrenal gland, but aldrin epoxidase, ethoxycoumarin O-deethylase, and ethoxyresorufin O-deethylase activities were below detection limits. Although fetal hepatic cytochrome P450 was not detected, low activities of aldrin epoxidase and ethoxycoumarin O-deethylase, but no ethoxyresorufin O-deethylase, could be detected in fetal liver. These enzymes attained adult marmosets activities when the offspring were approximately 2 months of age.

7-Alkoxycoumarin O-Dealkylase

Collection and analysis of semen from the common marmoset (Callithrix jacchus).

The authors examined the seminal characteristics of 16 male common marmosets (Callithrix jacchus) to provide baseline data for future studies of the reproductive biology of this species. Semen samples were collected by electroejaculation. There was considerable inter- and intra-male variation in all seminal characteristics. The median seminal volume was 30 microliters (range 8 to 85 microliters), and the median total sperm count was 5.1 x 10(6) sperm (range, 0.1 to 43 x 10(6]. The median progressive sperm motility was 48% (range, 10% to 76%), and 49% of the sperm exhibited normal morphology (range, 24% to 81%). Three types of sperm head abnormalities and eight types of tail defects were noted. Tail defects were common (median, 50%; range, 17% to 76%), whereas head defects were relatively rare (median, 4.5%; range, 0% to 24%). The results indicate that semen samples can be routinely collected from this species, but considerable inter- and intra-male variation can be expected. It is therefore important to examine several semen samples from each male marmoset to obtain an accurate seminal picture.

Aging

Plasma vitamins A and E and hydrogen peroxide-induced in vitro erythrocyte haemolysis in common marmosets (Callithrix jacchus).

Plasma total lipid, cholesterol, all-trans retinol (vitamin A) and alpha-tocopherol (vitamin E) concentrations, and the susceptibility of erythrocytes to hydrogen peroxide-induced haemolysis in vitro were investigated in healthy laboratory-bred common marmosets (Callithrix jacchus). The concentrations of alpha-tocopherol and total cholesterol were similar to those of control human subjects. The mean lipid concentration was higher (P less than 0.025) and the retinol concentration lower (P less than 0.001) in the marmosets. The susceptibility of the erythrocytes of the marmosets to hydrogen peroxide-induced haemolysis was high, both in absolute value and relative to the controls. Changes in phospholipid and fatty acid composition might have rendered the red cells susceptible to oxidative stress.

Adult

Connective tissue of the livers of newborn and adult marmosets (Callithrix jacchus).

Immunofluorescence microscopic and electron microscopic investigations revealed components of the matrix and of the basal lamina (collagen type I, III, IV and V, BL-heparan sulfate and fibronectin) in the sinus wall (Disse's space) of the livers of newborn and adult marmosets (Callithrix jacchus). Collagen type I was missing in both the two age groups. Small amounts of laminin were present in the livers of newborn and absent in those of adult animals, whereas collagen type III occurred in the form of delicate fibres. Light microscopic inspection showed a continuous distribution of all other components in the sinus wall. The amount of collagen type III and V increased depending on the age. Electron microscopic investigations revealed single or bundled fibrils (20-30 nm) and filaments (10-12 nm). After addition of tannic acid, plaques of a fine-filamentous network and incorporated granules were observed. After addition of resting Ruthenium Red, electron-dense granules (20-60 nm) were irregularly distributed in the structureless space, resting on collagenous fibrils and cell membranes. The fibrils were allocated to collagen type III, the filaments to collagen type V. The plaques were supposed to contain heparan sulfate, collagen type IV and fibronectin. The absence of a Lamina densa of the basal lamina was attributed to the absence of laminin which probably plays an important role in the formation of this layer. Differences in the distribution pattern of the matrix components and thus a functional mosaic of the permeability of Disse's space were assumed. The complete absence of collagen type I and laminin in the lobules makes the adult marmoset liver especially suited for studies on the importance of this collagen type under pathological conditions, since both components are expressed in this way.

Animals

Lymphocyte subsets in the young and aging marmoset (Callithrix jacchus).

T lymphocytes were studied in healthy young and old marmosets (Callithrix jacchus). Data indicate that monoclonal antisera to human T lymphocyte antigens can be used to identify these cells in marmosets. Total T and suppressor T cells were lower in the older group; there were no differences in helper T or in B cells. Helper/suppressor ratios (T4/T8) were increased in the older group. Thus, immune system alternations with aging and/or immune deficiency syndromes may be studied in this animal model using available reagents.

Aging

Determination of ovulation and pregnancy in the marmoset (Callithrix jacchus) by monitoring of urinary hydroxypregnanolone excretion.

In Callithrix jacchus the urinary excretion of hydroxypregnanolone (5 alpha-pregnane-3 alpha, 7 alpha-diol-20-one) shows a luteal rise during the ovulatory cycle. This progesterone metabolite can therefore be used as an indication of ovulation, implantation, and subsequently for the persistence of the pregnancy. The excretion can be monitored by high performance thin-layer chromatography (HPTLC) and postchromatographic derivatization after enzymatic hydrolysis of the conjugate. Profiles of urinary hydroxypregnanolone levels are presented and correlated with luteinizing hormone excretion. The method is noninvasive and therefore suited for long-term studies in these monkeys.

Animals

Identification of the main gestagen metabolite in marmoset (Callithrix jacchus) urine by NMR and MS spectroscopy.

Hydroxypregnanolone is the most abundant progesterone metabolite in the urine of marmoset monkeys (Callithrix jacchus). The substance is excreted as conjugate. The concentration of this steroid may be monitored by high performance, thin layer chromatography and postchromatographic derivatization. Hydroxypregnanolone was purified and subsequently identified by NMR spectroscopy and gas chromatography/mass spectroscopy. The exact chemical structure is 5 alpha-pregnane-3 alpha, 7 alpha-diol-20-one.

Animals

Endogenous N-excretion and minimal protein requirement for maintenance of the common marmoset (Callithrix jacchus).

The protein requirement for maintenance of the marmoset Callithrix jacchus was investigated by factorial calculation via the N balance technique. Six adult male marmosets were fed a protein-free pelleted diet for 22 days. When a low protein diet (6%) was fed in the preperiod, only 7 days were necessary and when fed a higher protein diet (18%) 10 days were necessary to reach a minimum of N excretion during protein depletion. Body weight losses averaged 11% and food intake was 21% lower in the protein free period. The average endogenous urine N (EUN) was 62.1 mg N and endogenous fecal N (EFN) 49.2 mg N/kg W0.75. Body surface losses (BSN) were assumed to be 20 mg N/kg W0.75. The total endogenous loss of 131.3 mg N/kg W0.75 is similar to that of other species. Net protein utilization (NPU) of well balanced proteins, determined near the N equilibrium, was 51.8%. The calculated net protein requirement amounts to 313.6 mg N/kg W0.75, which corresponds to a dietary protein content of 6% in a diet of high caloric density, (about 19-20 MJ/kg dry matter) when the food intake is 3.3% of body weight.

Animal Nutritional Physiological Phenomena

Refractoriness of Callithrix penicillata red blood cells to Plasmodium falciparum in vivo and in vitro.

Attempts to infect the New World marmot Callithrix penicillata with Plasmodium falciparum were unsuccessful. Attempts were also made to infect red blood cells of C. penicillata and Saimiri sciureus with P. falciparum in vitro, and these too were unsuccessful due to a high rate of hemolysis produced by apparently adverse culture conditions. It is concluded that modifications to the existing culture conditions will need to be made before successful parasitemia can be induced in vitro in simian erythrocytes.

4-Aminobenzoic Acid

Experimental infections of simians with human malaria: attempts to infect Callithrix penicillata with Plasmodium falciparum.

After reviewing the use of non-human primates of the Old and New Worlds for human malaria research, we concluded that another experimental animal which is easily available to use and possible to rear indoors is needed. Thus, we studied the susceptibility of the marmoset Callithrix penicillata to Plasmodium falciparum erythrocytic infections. The marmosets received various P. falciparum human isolates, directly from a patient and from continuous cultures. The Palo Alto strain, which has been adapted to the night monkey Aotus trivirgatus and further maintained in the squirrel monkey Saimiri sciureus was also used. In a total of 20 marmosets we performed 31 inoculations, with 10(5) to 10(9) parasites, intraperitoneally, intracardiacly or intravenously. Blood samples from each animal were examined daily up to day 90 post-inoculation. None of the intact marmosets developed patent infections. Four out of 19 C. penicillata, previously splenectomized, showed circulating parasites for up to five days after intravenous inoculation with the Palo Alto strain, becoming negative thereafter. Neither the addition to the simian diet of p-aminobenzoic acid, essential for the parasite metabolism, nor drug-immunosuppression, improved the marmoset susceptibility to P. falciparum.

Animals

Presence of pH2-sensitive circulating interferon among Callithrix jacchus marmosets.

Significant and relatively stable levels of serum-interferon were demonstrated in a Callithrix jacchus population. This circulating interferon was acid-sensitive in all cases, classifying it as immune or "gamma-type" interferon. Our results in these hematopoietic chimeras suggest that the presence of immune-type or at least pH 2-sensitive interferon could be related to the presence of two allogenic lymphocyte populations in each marmoset.

Animals

The postnatal development of the temporomandibular joint of the common marmoset (Callithrix jacchus).

The temporomandibular joints (TMJ) of 55 male and 50 female common marmosets (Callithrix jacchus) with an age range of 1 day- to < 12-yr-old have been studied to extend the knowledge on the craniomandibular articulation of this primate. Details of changes in the bone structure, gross and functional anatomy, and histologic appearance of the marmoset TMJ during the neonatal period, infancy, childhood, adolescence, and adulthood are compared with those which occur in the TMJ of man. It is concluded that further investigations on the structure and function of the marmoset TMJ and jaws may establish this nonhuman primate as a valuable analog for TMJ research in man.

Aging

Skin reaction in Callithrix jacchus penicillata to phytohemagglutinin.

Sixty marmosets (Callithrix jacchus penicillata) were intradermally tested with phytohemagglutinin. It was possible to classify this population into three groups on the basis of the reactions: 1. negatives, 2. those which showed just local hemorrhage, and finally 3. a group which developed a wheal as well as hemorrhage. The biopsy at the site of the reaction demonstrated several microscopic foci. This finding contrasted with the homogeneous cellular infiltration found in the human controls.

Animals

Poxvirus infection in a colony of common marmosets (Callithrix jacchus).

An epizootic poxvirus infection occurred in a colony of 80 common marmosets (Callithrix jacchus) recently introduced to a laboratory facility. Over an 18-week period, 29 of the monkeys exhibited skin lesions that persisted for 4-6 weeks. Although eight marmosets died during the outbreak, their deaths were not attributed directly to the poxvirus infection. The skin lesions developed over the entire body surface including the soles and palms. Initially characterized as erythematous papules, they quickly changed to elevated coalescing lesions with extensive scab formation. Histopathologically, the lesions revealed moderate to marked acanthosis, and they progressed to full-thickness epidermal necrosis and ulceration. Intracytoplasmic inclusion bodies were observed occasionally within degenerate keratinocytes. These inclusions most probably constituted the intracytoplasmic aggregates of viral particles observed ultrastructurally and confirmed as members of the poxvirus group by negative staining of direct skin scrapings.

Animals

The structure and epididymal maturation of the spermatozoon of the common marmoset (Callithrix jacchus).

Maturation of the spermatozoon of the common marmoset (Callithrix jacchus) during epididymal transit was investigated using light and electron microscopy. Except for the caudal migration of the cytoplasmic droplet there were no apparent ultrastructural modifications, although interesting morphological features of the sperm head were observed such as the substructure of the acrosome and a waist at the equatorial region. Alteration to the plasmalemma during maturation was reflected by an increasing capacity of the sperm surface to bind wheat germ agglutinin (recognising n-acetyl-d-glucosamine) but not ricin communis or concanavalin agglutinins. This change was concomitant with the development of sperm fertilising capacity in this species.

Acrosome

Hematologic and immunologic responses in common marmosets (Callithrix jacchus) infected with Plasmodium knowlesi and Epstein-Barr virus.

The hematologic and immunologic responses to infection with either the Epstein-Barr virus alone or infection with Epstein-Barr virus and Plasmodium knowlesi were studied using common marmosets (Callithrix jacchus). The assays performed included complete blood cell counts, determinations of natural killer cell activity, and determinations of antibody titers to Epstein-Barr virus early antigen, virus capsid antigen and the nuclear antigen. While no animal showed signs of lymphoproliferative disease, it was found that animals infected with Epstein-Barr virus became positive for early antigen, virus capsid antigen and nuclear antigen at low levels. No difference in antibody titers between Epstein-Barr virus infected animals and co-infected animals was observed. An increase also was found in the number of leukocytes in all groups, and an increase in natural killer cells following infection with Epstein-Barr virus. Some depression in natural killer cells was observed in the co-infected animals when compared to Epstein-Barr virus infected animals.

Animals

Stabilities of some constituents of marmoset (Callithrix jacchus) plasma under various conditions of storage.

The stability of various marmoset (Callithrix jacchus) plasma constituents was investigated after storage at room temperature, 4 degrees C, and -20 degrees C. The method of sequential analysis ensured that the between-run bias of the methods of analysis used was drastically reduced, and the definitions of stability were linked to the imprecision of these methods. Optimal conditions for storage for as long as 48 h depended on the analyte being measured. Room temperature was optimal for cholinesterase and acetylcholinesterase; 4 degrees C for protein, albumin, alanine aminotransferase, isocitrate dehydrogenase, sorbitol dehydrogenase, lactate dehydrogenase, and glutamate dehydrogenase; and -20 degrees C for glutathione reductase and alkaline phosphatase. For aspartate amino-transferase and gamma-glutamyltransferase, either 4 degrees C or -20 degrees C would be suitable. Reasons are advanced for some conflicting reports in the published work, and we emphasize the need to investigate each analyte and species separately.

Animals