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PubMed1996

Maturation of sperm motility in the epididymis of the common marmoset (Callithrix jacchus) and the cynomolgus monkey (Macaca fascicularis).

The acquisition by spermatozoa of the capacity for movement upon liberation from the epididymal duct into buffer is one of the obvious changes associated with sperm maturation and, hence, studies of sperm kinematics might provide good indices for sperm maturation. Profiles of development in the movement pattern of spermatozoa taken from six regions of the epididymis were established in marmoset and cynomolgus monkeys using computer-assisted sperm analysis. Motion of spermatozoa from initial regions was sluggish and irregular, then developed in the more distal region into erratic movement effected by an increase in the vigour of flagellation as reflected by curvilinear velocity. The tendency of immature spermatozoa to display circular motion was more common in the marmoset than in the cynomolgus monkey. In the marmoset the most drastic changes in percentage motility and kinematic parameters of spermatozoa occurred between the distal caput and the proximal corpus; maximal values for these parameters were found around the distal corpus epididymis. For the cynomolgus spermatozoa the sharpest gain in percentage motility was also achieved between the caput and proximal corpus epididymis, but with full kinematic development in the proximal cauda epididymis. These maturational changes were not synchronous among spermatozoa from the same site as they moved along the epididymis, as reflected in the heterogeneity of each sample in the kinematic properties of individual spermatozoa, especially those from the proximal corpus epididymis. The maturational profiles in the monkeys are comparable to the situation in the human, for which they may provide a useful model.

Animals↗
PubMed2005

S-cones do not contribute to the OFF-midget pathway in the retina of the marmoset, Callithrix jacchus.

It is well established that in primate retina both medium- and long-wavelength-sensitive cone types provide input to the midget-parvocellular pathway. The question, however, whether short-wavelength-sensitive (S or 'blue') cones provide input to the OFF-division of the midget-parvocellular pathway is still controversial. In the present study, we investigated the connections of nearly 400 S-cones with OFF-midget bipolar cells in central and peripheral retina of a New World monkey, the marmoset. Horizontal sections or pieces of whole retinae were double-labelled with an antiserum to S-cone opsin to identify S-cones and antibodies to the cell adhesion molecule CD15 to identify OFF-midget bipolar cells. Peanut agglutinin coupled to a fluorescent tag was used to label the cone pedicles of all cone types. Peanut agglutinin was also used to distinguish S-cones from the other cone types. The sections were analysed with deconvolution microscopy. We found that nearly all pedicles of medium- and long-wavelength-sensitive cones are located opposite distinct dendritic clusters formed by OFF-midget bipolar cells. By contrast, the S-cone pedicles are not located opposite dendritic clusters. Instead, S-cones make sparse contacts with CD15-labelled processes. Some of these processes protruded from OFF-midget bipolar clusters, whereas others could be traced to a diffuse bipolar cell type. Thus, in the marmoset retina the midget-parvocellular system does not carry a blue-OFF signal.

Animals↗
PubMed1999

Temporal contrast sensitivity in the lateral geniculate nucleus of a New World monkey, the marmoset Callithrix jacchus.

1. The temporal contrast sensitivity of koniocellular, parvocellular and magnocellular cells in the lateral geniculate nucleus (LGN) of nine adult marmosets was measured. The receptive fields of the cells were between 0.3 and 70 deg from the fovea. The stimulus was a large spatially uniform field which was modulated in luminance at temporal frequencies between 0.98 and 64 Hz. 2. For each cell group there was a gradual increase in modulation sensitivity, especially for temporal frequencies below 8 Hz, with increasing distance from the fovea. At any given eccentricity, magnocellular cells had the greatest sensitivity. In central visual field, the sensitivity of koniocellular cells lay between that of parvocellular and magnocellular cells. In peripheral visual field (above 10 deg eccentricity) koniocellular and parvocellular cells had similar sensitivity. 3. The contrast sensitivity of each cell class was dependent on the anaesthetic used. Cells from animals anaesthetized with isoflurane were less sensitive than cells from animals anaesthetized with sufentanil. This effect was more marked for temporal frequencies below 4 Hz. 4. These results are incompatible with the notion that the koniocellular pathway is functionally homologous to a sluggish, W-like pathway in other mammals. At least in terms of their temporal transfer properties, many koniocellular cells are more like parvocellular cells.

Animals↗
PubMed2001

Spatial properties of koniocellular cells in the lateral geniculate nucleus of the marmoset Callithrix jacchus.

1. The receptive field dimensions, contrast sensitivity and linearity of spatial summation of koniocellular (KC), parvocellular (PC) and magnocellular (MC) cells in the lateral geniculate nucleus (LGN) of 11 adult marmosets were measured using achromatic sinusoidal gratings. 2. The receptive field centre diameter of cells in each (PC, KC and MC) class increases with distance from the fovea. There is substantial overlap in centre size between the three cell classes at any eccentricity, but the PC cells have, on average, the smallest centres and the KC cells have the largest. Some PC and KC cells did not respond at all to the grating stimulus. 3. The contrast sensitivity of the receptive field centre mechanism in KC cells decreases in proportion to the centre area. A similar trend was seen for the surround mechanism. These characteristics are common to PC and MC cells, suggesting that they originate at an early stage of visual processing in the retina. 4. The KC cells showed, in general, lower peak evoked discharge rates than PC or MC cells. The spontaneous discharge rate of KC cells was lower than that of PC cells and similar to that of MC cells. 5. The majority of cells in all divisions of the LGN show linear spatial summation. A few cells did show non-linear spatial summation; these cells were predominantly located in the MC and ventral KC layers. 6. The ventral KC layers below and between the MC layers contain cells with larger and more transiently responding receptive fields than cells in the more dorsal KC layers. 7. We conclude that many of the contrast-dependent spatial properties of cells in the marmoset LGN are common to PC, MC and KC cells. The main difference between KC cells and the other two classes is that there is more variability in their response properties, and they are less responsive to high spatial frequencies.

Animals↗
PubMed1996

Patterns of prenatal survival in the common marmoset (Callithrix jacchus).

Fifty common marmoset pregnancies were monitored using ultrasound. The objective was to ascertain if fetal mortality was related to litter size. Prior to analysis we determined abortion rate and litter size were not influenced by repeated ultrasound. Mortality was unrelated to litter size and occurred fairly late in gestation. All singletons born in this study began gestation as twins. It is hypothesized that marmosets may be able to adjust litter size late in pregnancy in response to proximate environmental factors.

Abortion, Veterinary↗
PubMed1999

Efficacy and effects of short- and medium-term contraception in the common marmoset (Callithrix jacchus) using melengestrol acetate implants.

This study examines the effect of melengestrol acetate (MGA) implants on reproductive function and various biochemical parameters, ovarian activity, and uterine morphology in ten female common marmosets implanted for either 6-8 or 19-21 months. Measures of body weight, concentrations of urinary glucose and blood liver enzymes were taken. Ovarian activity was assessed by analysis of urinary progestin levels and ultrasound examinations of the ovaries. Ultrasonography was also used to evaluate uterine morphology. MGA was highly effective in preventing pregnancies in the study animals. No changes in biochemical parameters were found; however, seven females developed a substantial weight gain during the study. Follicular development was not suppressed, as indicated by the presence of antral follicles, luteinized structures, and elevated urinary progestin levels. The uteri of the MGA-treated subjects were moderately enlarged with a thickened endometrium that showed a marked change in structural appearance indicative of hypertrophy and decidualization. After implant removal these changes quickly disappeared and all females ovulated within 3 weeks and conceived within 4 months post-treatment. MGA appears to be an acceptable contraceptive in the marmoset, although non-steroidal methods should be evaluated as possible potential alternatives.

Animals↗
PubMed1999

Unrearable litters and prenatal reduction of litter size in the common marmoset (Callithrix jacchus).

It is widely believed that common marmosets (Callithrx jacchus) typically give birth to twins under natural conditions. In captivity, however, births of triplets or even larger litters are common, although parents rarely succeed in rearing more than two offspring. The traditional interpretation is that captive conditions, notably the ready availability of food, have led to increased reproductive output, perhaps involving a higher ovulation rate. The present paper provides evidence, combined from ultrasound examinations between ovulation and birth and hysterotomies conducted during the late embryonic and early fetal phase, that the litter size can be progressively reduced during pregnancy without spontaneous abortion. There is an unusually long lag phase prior to the onset of embryonic growth in common marmosets; the fetal stage does not begin until day 80 of the 144-day pregnancy. Reduction in litter size occurs during embryonic stages (up to day 80), and continues into the fetal stages. These results indicate that the common marmoset is adapted for flexible modification of litter size between ovulation and birth. The high incidence of triplet births in captive colonies may therefore be an expression of an adapted natural developmental process under artificial circumstances.

Abortion, Veterinary↗
PubMed2005

Comparison of the effects of Percoll and PureSperm on the common marmoset (Callithrix jacchus) semen.

Density gradient centrifugation is a widely used technique for the separation of motile from non-motile sperm, for the removal of contaminating agents such as bacteria and viruses, and for the removal of seminal plasma or cryoprotectant. In the choice of a density gradient medium for a new species, it is important to perform toxicity tests. The present study was carried out to evaluate the potential toxic effects of two silica-based density gradient products (Percoll and PureSperm), on the sperm of the common marmoset. We assessed two different batches of Percoll (polyvinylpyrrolidone (PVP)-coated colloidal silica particles) and one of PureSperm (saline-coated colloidal silica suspension) by means of a computer-aided sperm analysis on semen collected by vibrostimulation. The results showed that although some of the sperm patterns of movement and viability changed significantly over time, and provide a first description of marmoset sperm motility changes under capacitating conditions, there was no significant difference in the sperm treated with Percoll or PureSperm in comparison with the control. We conclude that simple exposure to either of these products does not have a negative effect on viability or motility of marmoset sperm.

Animals↗
PubMed1991

Immunohistochemical localization of collagenous components in healthy periodontal tissues of the rat and marmoset (Callithrix jacchus). II. Distribution of collagen types IV, V and VI.

The immunohistochemical distribution of collagen types IV, V and VI has been demonstrated in healthy periodontal tissues of rats and marmosets following decalcification of the maxillae and mandibulae in 0.2 N HCl. An intense fluorescence with anti-collagen type IV antibodies was demonstrated in the basement membranes of the epithelium and of the blood vessels and nerves. In the alveolar bone stroma and in the periodontal ligament (PL) collagen type IV was present only in the basal membranes of the blood vessels and nerves. In comparison, collagen type V was observed in a fibrillar pattern in the gingival connective tissue, as well as the PL. In the PL, type V collagenous fibers demonstrated a parallel distribution with stronger fluorescence near the cementum surface. Collagen type VI could be demonstrated in fine fibers present in the gingival connective tissue and the PL. Blood vessels and nerves were not stained in the marmoset, but were in the rat, where a localization of collagen type VI was demonstrated in these areas. Alveolar bone and cementum, as well as the Sharpey's fibers embedded in these tissues, were not stained with antibodies against collagen type V and type VI, but a pericellular localization of these collagenous components could be observed. Collectively, these results provide basic information on the relative distribution of different collagen types in normal tissues of rats and marmosets that will be required for future studies on the effects of pathological, reparative and regenerative processes.

Animals↗
PubMed1992

Immunohistochemical localization of collagenous components in healthy periodontal tissues of the rat and marmoset (Callithrix jacchus). I. Distribution of collagen types I and III.

The distribution of collagen types I and III was demonstrated in healthy periodontal tissues of the rat and marmoset using immunofluorescent localization after decalcification of the maxillae and mandiblae in 0.2 N HCl. An intense fluorescence in the alveolar bone and cementum matrix, as well as in the soft periodontal tissue, was demonstrated with anti-collagen type I antibodies. In the gingival connective tissue and in the periodontal ligament thick fibers of collagen type I could be observed. The fluorescent reaction in the rat periodontal ligament was not strong in comparison to the marmoset periodontal ligament. Sharpey's fibers, inserting into the cementum and alveolar bone, were also stained. On the other hand, collagen type III could not be demonstrated in the hard periodontal tissues, but could be in the bone marrow stroma and the incremental lines as well as around the Sharpey's fibers of the cementum, in accordance to previous studies. In the gingival connective tissue a strong staining was evident, especially near the basement membrane. The periodontal ligament showed an intense fluorescence that was, in some areas, continuous with Sharpey's fibers inserting into the cementum. The distribution of collagen types I and III was demonstrated with immunohistochemical techniques in the rat and marmoset periodontium. These results provide necessary information on healthy tissues that will be required for future studies on the effects of pathological, reparative and regenerative processes.

Alveolar Process↗
PubMed1998

Changes in lymphoid tissue after treatment with a gonadotropin releasing hormone antagonist in the neonatal marmoset (Callithrix jacchus).

PROBLEM: The effect of neonatal treatment with a gonadotropin releasing hormone (GnRH) antagonist on the morphology and distribution of lymphocytes in lymphoid tissue of the infant marmoset was examined. METHOD OF STUDY: From a screened panel of antihuman antibodies for specific immune cells, antibodies for the CD20 and CD3 antigens showed excellent reactivity with marmoset tissue. Five sets of marmoset twins were treated with either the GnRH antagonist or a vehicle from birth, and were euthanized at 7 to 9 (3 sets) or 16 to 20 weeks (2 sets) of age. The spleen, thymus, and inguinal lymph nodes from each animal were processed for immunocytochemistry, and the number of cells expressing the CD20 and CD3 antigens were quantified. RESULTS: Control twins exhibited high plasma levels of testosterone, characteristic of the neonatal period, whereas testosterone concentrations were reduced (P = 0.001) to detection limits in the GnRH antagonist-treated twins. Microscopic evaluation suggested that treatment reduced the volume and cellularity of the thymic cortex, resulting in a decrease in the cortical-to-medullary ratio. Treatment reduced (P = 0.046) the number of thymocytes expressing the B-cell antigen (CD20) and marginally lowered (P = 0.067) the number expressing the T-cell antigen (CD3) in the thymic medulla. In the spleens of treated animals, periarterial lymphatic sheaths were less prominent on microscopic examination, and there were marginally fewer (P = 0.064) CD3+ cells. Numbers of CD20+ lymphocytes in the peripheral white pulp of the spleen and in the germinal centers of the lymph nodes, or CD3+ cells in the paracortex and germinal centers of the lymph nodes, were not altered by treatment. CONCLUSION: Neonatal treatment with a GnRH antagonist may alter maturational processes for B and T cells in the thymus and spleen of the marmoset and may deprive the immune system of its normal sensitivity to GnRH at a potentially critical time in development.

Animals↗
PubMedDate not supplied

Radiographic anatomy of the thorax and abdomen of the common marmoset (Callithrix jacchus).

A standard radiographic procedure was developed for the thorax and abdomen in the common marmoset. A description and reference values for the corresponding radiographic anatomy are given. Radiographs were obtained from 17 anaesthetized healthy mature marmosets ranging from 1.5 to 9 years and 328 to 506 g. Left-to-right lateral recumbent and ventrodorsal whole-body radiographs made at end inspiration are recommended. Images of the heart, lungs, liver, gastric axis, and at least one kidney could be evaluated consistently. A generalized interstitial/peribronchial pattern was normally present. The mean of the vertebral heart size +/- SD on dorsoventral or ventrodorsal views was 9.42 (+/- 0.44), ranging from 8.8 to 10.6. Abdominal detail was generally poor. The gastrointestinal structures could often only be identified because of their luminal gas. The right liver lobes were prominent and extended caudally beyond the costal arch. The pylorus was in a central position and the spleen could not be distinguished. Additionally, pancreas, lymph nodes, urinary bladder, and ureters were not identified. A statistically significant difference (P < or = 0.05) between female and male kidney length existed. This study emphasizes that significant species differences exist, and simply applying canine or feline radiographic interpretation will result in misinterpretation.

Abdomen↗
PubMedDate not supplied

Transcutaneous ultrasonography of the abdomen in the normal common marmoset (Callithrix jacchus).

Ultrasonographic examinations were performed on 17 clinically healthy adult common marmosets to gain information about the normal abdominal echoanatomy. The marmosets were 1.5-9 years of age and weighed between 328 and 506g. Marked species-specific differences compared with the cat or dog were noted. Good images of the kidneys, bladder, spleen, adrenal glands, liver, and the gastrointestinal tract could be obtained. The pancreas, caecum, and abdominal lymph nodes were not seen. The spleen was the least echogenic organ, followed by the medium echogenic liver and the sometimes isoechoic, but mostly hyperechoic renal cortex. The kidneys had a poor corticomedullary distinction. The prominent right lobes of the liver extended caudally far beyond the costal arch. The gallbladder had a bi- to multi-lobed appearance with a wide, tortuous cystic duct. The pylorus was centrally positioned. The adrenal glands were readily seen, but should not be confused with the adjacent spleen. A statistically significant (P<0.05) difference between female and male kidney, and right adrenal gland length was present.

Abdomen↗
PubMed1998

Behavioral and single chorda tympani taste fiber responses in the common marmoset, Callithrix jacchus jacchus.

Gustatory responses of the common marmoset were studied using single fiber recordings from chorda tympani (CT) nerve and two bottle preference (TBP) tests. Hierarchical cluster analysis of 43 fibers' response profiles revealed 3 major clusters of fibers characterized by predominant sensitivity to sweeteners (S cluster), bitter compounds (Q cluster) or acids (H cluster). NaCl as well as LiCl did not stimulate CT taste fibers. The TBP tests showed relationship between a compound's ability to stimulate the taste fibers and the animals' consumption. Activity in the S cluster was associated with preference, while the activity in the Q cluster was associated with rejection. Marmosets neither preferred nor rejected sweeteners which did not stimulate any CT fibers.

Animals↗
PubMed2004

Chromatic and spatial properties of parvocellular cells in the lateral geniculate nucleus of the marmoset (Callithrix jacchus).

The parvocellular (PC) division of the afferent visual pathway is considered to carry neuronal signals which underlie the red-green dimension of colour vision as well as high-resolution spatial vision. In order to understand the origin of these signals, and the way in which they are combined, the responses of PC cells in dichromatic ('red-green colour-blind') and trichromatic marmosets were compared. Visual stimuli included coloured and achromatic gratings, and spatially uniform red and green lights presented at varying temporal phases and frequencies.The sensitivity of PC cells to red-green chromatic modulation was found to depend primarily on the spectral separation between the medium- and long-wavelength-sensitive cone pigments (20 or 7 nm) in the two trichromatic marmoset phenotypes studied. The temporal frequency dependence of chromatic sensitivity was consistent with centre-surround interactions. Some evidence for chromatic selectivity was seen in peripheral PC cells. The receptive field dimensions of parvocellular cells were similar in dichromatic and trichromatic animals, but the achromatic contrast sensitivity of cells was slightly higher (by about 30%) in dichromats than in trichromats. These data support the hypothesis that the primary role of the PC is to transmit high-acuity spatial signals, with red-green opponent signals appearing as an additional response dimension in trichromatic animals.

Algorithms↗