Location of nucleolar organizing regions on the chromosomes of the Syrian hamster (Mesocricetus auratus) and the Djungarian hamster (Phodopus sungorus)

Terminal chromosome associations ("satellite associations") in ASG-banded preparations have been used to determine the number and location of staellites in the Syrian hamster (Mesocricetus auratus) and the Djungarian hamster (Phodopus sungorus). Five pairs of satellites are found in the former and four in the latter. Nucleolar organizing regions (NORs) were visualized with the Ag-AS silver precipitation technique, and their number and position corresponded exactly with the number and position of satellites in Phodopus, where positive chromosome identification can be made in the absence of banding. Numerical agreement is exact in Mesocricetus as well, and the morphology of the silver-tagged NOR-bearing chromosomes strongly suggests that corrrespondence also occurs in this species.     

Dietary protein restriction and selective preference for a protein-containing diet in the golden hamster (Mesocricetus auratus)

The corrected midparental height method was introduced by Tanner in 1970 (Tanner method) and is commonly used to estimate target height in children to evaluate the effectiveness of growth-promoting therapies. It has not been established if the equation used to compute target height should be the same for children with short, normal, or tall parents. In this study, we examined the predicted target height values by parental heights in a large population-based study (n = 2402). A simple linear function of midparental height (x) was proposed to estimate target height (y): y = 45.99 + 0.78x (boys), y = 37.85+0.75x (girls), with a 95% predicted interval of about +/-10 cm. The prediction model was similar for boys and girls in SD scores (SDS), and was not affected by assortative mating or difference in parental heights. The model may underestimate the potential stature by about 2 cm for children with midparental height below -2 SDS, or 163 cm. In comparison, the Tanner method may lead to a 6-cm error in underestimating target height for these children. The function would be a better choice than the Tanner method for estimating target height in the clinical evaluation of growth promotion treatments because it is common that short children also have short parents. Children with very short parents will usually be much taller than their parents in adult stature, and we believe that a different function should be developed. The results support the proposed nondominant, non-sex-linked, polygenic inheritance in stature. The estimated heritability values were 0.75-0.78 in cm or 0.55-0.60 in SDS.     

Circadian rhythms of locomotor activity in the golden hamster (Mesocricetus auratus) measured with two different techniques.

Compared running wheels and spring-suspended cages as measurement devices for evaluating circadian locomotor activity rhythm. 12 golden hamsters were tested individually in a spring-suspended cage; 6 also had access to running wheels. Ss were exposed to 5 different levels of constant illumination, each condition lasting for several wks, and to a light-dark cycle. The onset of activity in the spring-suspended cage preceded the onset of activity in the running wheel by an amount which is a function of the circadian period. The increment by which the period changes in response to changes in light intensity equals, approximately, the changes of the interval between the 2 onsets. Animals with access to a running wheel show a tendency towards longer circadian periods. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monoclonal antibody-based immunohistochemical demonstration of Entamoeba histolytica in liver tissues of experimentally infected hamster (Mesocricetus auratus)

Histopathological changes and the presence of Entamoeba histolytica trophozoites was sequentially followed after intrahepatic inoculation of the parasites in 42 hamsters, 35 of which received no treatment whereas the remaining seven were treated with metronidazole. The liver tissues were examined for amoebic trophozoites by a monoclonal antibody (mAb)-based immunofluorescence assay (IFA), a mAb-based immunoperoxidase (IPx) and H & E staining. The number of hamsters developing abscesses was increased with time and was highest on day 30. Cellular infiltration with inflammatory cells and glycogen depletion were observed as early as day 5, followed thereafter by more intense inflammation of portal canals, periportal fibrosis, bile duct proliferation and hepatocyte degeneration. In 7 metronidazole-treated hamsters, no obvious pathological damage was seen. In a group of seven hamsters each, both IPx and IFA were positive in 3, 3, 4, 5 and 4 hamsters and in 3, 4, 3, 3 and 5 hamsters on days 5, 10, 15, 20 and 30, respectively. In 18 control hamsters, IPx, IFA and H & E were all negative. If the result from H & E was used as a gold standard, agreement between H & E and IFA and H & E and IPx were 91.4%, and 88.6%, respectively. Sensitivity and specificity were 93.8% and 89.5%, respectively for IFA, and 93.8% and 84.2%, respectively for IPx.     

Ultrastructure of proliferative ileitis in hamsters (Mesocricetus auratus)

The ileum of affected hamsters bore microvilli which were much shorter, less regularly arranged and less densely packed than those from control animals. Organelle derangements such as atrophy of mitochondria, degranulation and dilated cisterna of endoplasmic reticulum, were observed. Some hyperplastic epithelial cells contained multiple intracytoplasmic inclusion bodies and amyloid deposits were present extracellularly.     

In vitro analysis of oocyte cumulus complex pickup rate in the hamster Mesocricetus auratus

In mammals, the oocyte and its surrounding cumulus cells constitute on oocyte cumulus complex (OCC). During ovulation, OCCs are extruded into the peritoneal or bursal cavity, depending on the species, and are then rapidly picked up by the fimbria on the outer surface of the oviductal infundibulum and transported to the ampulla, where fertilization occurs. We developed a method to measure OCC pickup rates quantitatively in vitro, and we used this method to evaluate the effects of viscosity and temperature on pickup rates. Hamster infundibula are placed in a holding pipette in a chamber modified to study OCC pickup. Ciliary beat frequencies (CBF) can be measured in the same preparation. Pickup rates vary depending on the pathway on which the OCC travels over the surface of the infundibulum; however, rates for a given pathway are very consistent. The average pickup rate at room temperature calculated from three different pathways/infundibulum was 55.2 +/- 10.6 microns/sec. Both rates between infundibula from the same female and rates among infundibula from different females were in most cases similar. Preparations preincubated in vitro for 2.75 hr produced rates similar to nonpreincubated samples, while longer preincubation resulted in decreased rates. Inclusion of Ficoll in culture medium to increase viscosity caused a concentration-dependent decrease in both OCC pickup rate and in CBF. However, a significant decrease in OCC pickup rate was only observed at viscosities higher than those found in bursal fluid. When trials were run at physiological temperature (36.4 degrees C) rather ambient temperature, rates increased to 136.7 +/- 29.9 (SD) microns/sec. Linear regression analysis demonstrated a strong positive correlation (r = 0.94) between OCC pickup rate and temperature. The OCC pickup rate assay can be used experimentally, and should be valuable in evaluating factors that affect rate and in studies dealing with the mechanism of OCC pickup.     

Cross-immunity to Schistosoma mansoni and S. haematobium in the hamster

The CO2 and O2 tnesions were determined in the air cells of 14-16 day old chicken eggs before and after transfer to a 21% O2 in He or SF6 atmosphere. In the former gas mixture the air-cell PCO2 (which reflects the arterialized blood PCO2) fell rapidly from 32 torr in air to 17 torr in He-O2 attaining a new steady state in 2-4 h. In the SF6-O2 mixture PCO2 rose from 36 torr in a similar period. A similar PCO2 increase was also observed when eggs were compressed to 2 atm of air while exposure to 0.5 atm with a 40% O2-N2 mixture decreased PCO2. Since gas transport across the eggshell is by gas phase diffusion, these findings can be explained by the changes in the diffusion coefficient of CO2 which increase in the presence of He and decrease in SF6. Furthermore, the diffusion coefficient is also inversely related to the absolute pressure. Quantitative prediction of the changes of PCO2 in the He and SF6 mixture cannot be made, since the binary diffusion coefficients are not necessarily applicable in a ternary gas mixture. However, effective diffusion coefficients in these multicomponent mixtures can be derived on the basis of the observed PCO2 changes.     

Tyrosine hydroxylase- and/or aromatic L-amino acid decarboxylase-containing cells in the suprachiasmatic nucleus of the Syrian hamster (Mesocricetus auratus)

We assessed forearm vascular and blood pressure responses to dynamic leg exercise in patients 7 and 28 days postmyocardial infarction. To determine a possible association between abnormal exercise vascular responses and baroreflex dysfunction, integrated and carotid baroreflex sensitivity and forearm vascular responses (during application of subhypotensive lower body negative pressure) were assessed. On day 7, 42 patients were compared with 21 age- and sex-matched controls. All subjects were assessed for (1) forearm vascular resistance during semierect exercise, (2) blood pressure measurements during erect treadmill exercise, and (3) integrated, cardiopulmonary, and carotid baroreceptor sensitivity. These studies were repeated in 13 patients on day 28. Forearm vascular resistance increased during exercise by 36% +/- 63% in patients versus 121% +/- 105% in controls (P = 0.0001), and fell in 15 patients, a response seen in none of the controls. Exercise hypotension was demonstrated in 5 patients, all of whom had abnormal vasodilator vascular responses. Those patients with vasodilator responses had a lower left ventricular ejection fraction (52% +/- 12% vs 62% +/- 9%; P = 0.007), and lower cardiopulmonary mechanoreceptor sensitivity (-6.6 +/- 3.9 units vs +6.4 +/- 10.4 units, P = 0.02) than those with constrictor responses, respectively. In the 13 patients studied on day 28, the change in forearm vascular resistance was similar to that observed on day 7 (36% +/- 63% vs 46% +/- 73%). Paradoxical vasodilation of forearm vessels during leg exercise is common in patients studied 7 and 28 days postmyocardial infarction, and is associated with lower left ventricular ejection fraction and abnormal vascular responses during subhypotensive lower body negative pressure.     

Inhibition of lymphocyte proliferation by factor(s) produced by Schistosoma mansoni

Normal spleen cells of CBA mice or Fischer rats were cultured with mitogens or allogeneic cells, together with various substances of Schistosoma mansoni origin, and thymidine uptake was measured. The proliferation (DNA synthesis) of normal lymphocytes was inhibited by the incubation product of the parasite as well as by cell-free supernatant of schistosome culture. Inhibition was obtained only when active materials were added at the beginning of the culture. Both T and B cell proliferation were inhibited. The inhibitory activity found in cell-free supernatant suggested the release by the parasite of some factor(s) interfering with lymphocyte proliferation. Moreover, serum from rats infected by S. mansoni inhibited lymphocyte proliferation also. The inhibitor(s) appeared heat resistant, dialyzable and of low molecular weight (500-1000). Incubation of normal spleen cells with S. mansoni inhibitor(s) did not enhance the release of nonspecific suppressor cell factor. The inhibition of product(s) released by the parasite could explain part of the immunosuppression status found in schistosomiasis.     

Permeability of the pineal organ of the golden hamster (Mesocricetus auratus) to HRP with special reference to different types of blood capillaries

The pineal organ of the golden hamster consists of deep and superficial portions which are connected to each other by a stalk. The permeability of capillaries for horseradish peroxidase (HRP) injected intravenously was examined in sections of entire portions of the gland that cut either along coronal or sagittal planes. Two distinct portions of the parenchyma, i.e., dorsal major and ventral minor ones, were found in the superficial gland. Most of the capillaries in the dorsal portion were of the continuous type of endothelium, whereas those in the ventral portion were fenestrated. In the dorsal portion, HRP readily crossed the endothelium, permeated the basal lamina, flowed into the perivascular connective tissue space and intruded into the intercellular clefts of the parenchyma. In contrast, HRP was not found to penetrate through the endothelium of the capillaries in the ventral portion to reach the perivascular area, thereby leaving the intercellular clefts of the parenchyma free of HRP. In the deep gland the capillaries were exclusively of the nonfenestrated type. Intravenously injected HRP was prevented from crossing the endothelium by the tight junction. In some areas, HRP penetrated through the capillaries in the pia mater, and crossed the outer limiting membrane to reach the intercellular clefts of the parenchyma and the basal lamina of the capillaries in the peripheral region of the deep pineal gland. The junctions between endothelial cells were not penetrated by HRP. The observations indicate that the type of capillary, absence of perivascular spaces, and permeability in the deep pineal are all similar to these factors in the general brain tissue; they differ from these in the superficial pineal gland, in which the dorsal portion shows characteristics found in other endocrine glands, but the ventral zone exhibits a unique situations: the presence of a blood-pineal barrier with a pericapillary connective tissue area.     

Localization of histone H5 in the subunit organization of chromatin using immunoelectron microscopy

In avian erythroid cells the erythrocyte-specific histone H5 is involved, like H1, in the packing of nucleosomes in the 25-nm chromatin fibers. In this study the distribution of histone H5 along the polynucleosomal chains was visualized by immunoelectron microscopy. Trinucleosomes from chicken erythrocytes and liver were used in order to test the specificity of the reaction with purified rabbit anti-H5 antibodies at various ionic strengths (5-80 mM). Long-chain chromatin was then reacted with anti-H5 antibodies and with sorted monomeric ferritin conjugate under chosen conditions. The antigenic determinants of histone H5 in the 25-nm fiber of long-chain chromatin (at 80 mM NaCl) are as accessible to the specific antibodies as in trinucleosomes. When the immunocomplexes were examined by electron microscopy in a low-ionic-strength buffer, permitting maximum extension of the chromatin structure on the grid, clusters of compacted nucleosomes were seen, separated by short regions of relaxed nucleosomes. Single nucleosomes enlarged by the antibodies are sometimes visible in the extended domains. We conclude that histone H5 is located primarily on series of adjacent nucleosomes but it can also be found on single nucleosomes located in the H1-enriched extended domains.     

Neuronal projections from the mesencephalic raphe nuclear complex to the suprachiasmatic nucleus and the deep pineal gland of the golden hamster (Mesocricetus auratus)

Neuronal projections from the mesencephalic raphe system to the suprachiasmatic nucleus and the pineal complex were mapped in this study of the golden hamster, by use of the anterograde tracer Phaseolus vulgaris-leucoagglutinin and the retrograde tracer cholera toxin subunit B. From the median raphe nucleus, a rostral projection ascended in the ventral part of the mesencephalon to continue in the medial forebrain bundle of the forebrain. Nerve fibres from this bundle innervated the ventral and medial parts of the suprachiasmatic nucleus. At the level of the interpeduncular nucleus of the mesencephalon, fibres of the ventral bundle bent dorsally to reach the epithalamic area and to continue in the forebrain in a periventricular position. Some of these fibres innervated the dorsal tip of the suprachiasmatic nucleus. The dorsal raphe nucleus was the origin of a nerve fibre bundle, located in the periaqueductal gray of the mesencephalon, innervating the deep pineal gland and pineal stalk. Injection of cholera toxin B into the suprachiasmatic nucleus labelled cells in the median raphe. Combination of the retrograde tracing from the suprachiasmatic nucleus and serotonin transmitter immunohistochemistry showed that some of the cholera toxin B-immunoreactive nerve cells also contained serotonin. Thus, this study of the golden hamster shows a serotonergic projection from the median raphe nucleus to the suprachiasmatic nucleus and a projection from the dorsal raphe nucleus to the deep pineal gland supporting physiological indications of an influence of serotonin on the photoreceptive circadian system of the brain.     

Expression of recombinant antigens in Escherichia coli: application on immunochemical studies of Schistosoma mansoni tegumental antigens

Sm15 and Sm13 are recognized by antibodies from mice protectively vaccinated with tegumental membranes, suggesting a potential role in protective immunity. In order to raise antibodies for immunochemical investigations, the genes for these antigens were expressed in pGEX and pMal vectors so that comparisons could be made among different expression systems and different genes. The fusion proteins corresponding to several parts of the gene for the precursor of Sm15 failed in producing antibodies recognizing the parasite counterpart. On the other hand, antibodies raised against Sm13 MBP-fusion proteins recognized the 13 kDa tegumental protein. Thus the peculiarities of the gene of interest are important and the choice of the expression system must sometimes be decided on an empirical basis.     

Daily and photoperiodic 2-125I-melatonin binding changes in the pars tuberalis of the Syrian hamster (Mesocricetus auratus): effect of constant light exposure and pinealectomy

To clarify the relationship between neural crest cells and various developmental eye abnormalities, pregnant mice were administered an intraperitoneal injection of 12.5 mg/kg retinoic acid (RA) suspended in corn oil on day 7 of pregnancy (RA group). Control mice received an equal volume of corn oil only (control group). The fetuses were removed by laparotomy on day 18 of gestation. The fetal mortality was 46.3% in the RA group and 2.2% in the control group. The live fetuses in both groups were observed grossly, and the eyes were examined histologically in serial sections. In the RA group, gross malformations were observed, including microphthalmos (95.5%), cleft lip and palate (36.4%), and central nervous system anomalies (31.8%). In the control group, these malformations were seen in only 6.7%, 0%, and 2.2%, respectively. Histologic examinations in the RA group revealed microphthalmos (47.7%), anophthalmos (38.6%), faulty closure of the embryonic fissure (36.4%), developmental abnormalities of the vitreous (34.1%), aphakia (22.7%), goniodysgenesis (18.2%), and faulty separation of the lens vesicle (15.9%). They were detected in only 3.3%, 1.1%, 3.3%, 8.9%, 1.l%, 2.2%, and 2.2%, respectively, of the control group. These developmental eye abnormalities arose from abnormal migration of neural crest cells.     

Tubules of the trans Golgi apparatus visualized by immunoelectron microscopy

Tubules constitute an integral part of the Golgi apparatus and have been shown to form a complex and dynamic network at its trans side. We have studied in detail structural features of the trans Golgi network and its relationship with the cisternal stack in thin sections of Lowicryl K4M embedded human absorptive enterocytes by immunolectron microscopy. Immunoreactive sites for alpha1,3 N-acetylgalactosaminyltransferase and blood group A substance were detectable throughout the cisternal stack and the entire trans Golgi network. Furthermore, the entire trans Golgi network was reactive for CMPase activity. Evidence for two kinds of tubules at the trans side of the Golgi apparatus was found: tubules that laterally connect adjacent and distant cisternal stacks, and others extending from central and lateral portions of trans cisternae to form the complex and extensive trans Golgi network. Trans cisternae showed often the peeling-off phenomenon and were continuous with the trans Golgi network. Both, trans cisternae and tubules of the trans Golgi network exhibited regionally buds and vesicles with a lace-like, non clathrin coat, previously reported by others in NRK cells, which contained glycoproteins with terminal N-acetylgalactosamine residues. These buds and vesicle are therefore involved in constitutive exocytosis.     

Monoclonal antibody-based ELISA for the detection of circulating Entamoeba histolytica antigen in hepatic amebiasis in hamsters (Mesocricetus auratus)

Circulating amebic antigens were determined by using a sandwich ELISA with specific monoclonal antibody in the sera of 35 group I hamsters, 7 of which were sacrificed at intervals after hepatic inoculation with 500,000 axenically grown HM:1:IMSS strain of E. histolytica trophozoites, 7 group II infected hamsters in which metronidazole treatment was given and 18 group III uninfected controls. Amebic antigenemia was demonstrated in 5 of 7 (71.4%), 6 of 7 (85.7%), 7 of 7 (100%), 7 of 7 (100%) and 7 of 7 (100%) of group I hamsters on days 5, 10, 15, 20 and 30 of infections respectively, whereas 6 of 7 (85.7%) of group II hamsters were weakly positive, one was negative and all 18 group III hamsters were negative. The sensitivity of the assay was 100% after the animals were infected 15 days onwards. The level of antigenemia in hamsters of group I with abscess was significantly higher than those of the same group without abscess (p < 0.05). Absence or reduction of antigenemia after treatment could be interpreted to mean a positive test of cure and favorable therapeutic response. The MAb-PAb-based ELISA for the detection of circulating E. histolytica represents a simple and sensitive diagnostic test for invasive amebiasis in hamsters. Application of this test in amebic liver abscess patients should be of diagnostic value for indication of present infection or test of cure after successful treatment.     

The immunogenic effect of purified antigens of B. alexandrina against Schistosoma mansoni in experimental animals (I) as measured by worm load and viability of ova

Current stratigies for the control of schistosomiasis are based primarily on chemotherapy but successful vaccination against infection has been also demonstrated in several host parasite models. In this study, the immunogenic effect of two purified antigens (Fiv 20-29 000 daltons & Fv 20-24 000 daltons) extracted from non infected hepatopancreas of B. alexandrina as measured by worm load, state of copulation and viability of ova in tissues. The antigens were prepared using gel filtration chromatography and their molecular weights were estimated through sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Four dilutions from each antigen were prepared and injected in two groups (33 each) of Swiss albino mice at weekly intervals. A control group was injected with phosphate buffer saline (PBS) in the same manner. All mice were injected with 100 cercariae using immersion method. Sacrification was done regularly after 7 weeks of injection. On the basis of worm load, Fiv gave protection of 44% while Fv gave only 36%. The number of worms in copula was significantly reduced and they became delicate, fragile, stunted and malformed. Both antigens gave a significant reduction in total viable eggs in tissues.     

Epidermolysis bullosa acquisita diagnosed by direct immunoelectron microscopy of the conjunctiva

OBJECTIVE: To describe for the first time the direct immunoelectron microscopic pattern of immune deposits on the conjunctival basement membrane in epidermolysis bullosa acquisita (EBA). DESIGN: Case reports. PARTICIPANTS: Two patients. INTERVENTION: Epidermolysis bullosa acquisita associated with cicatrizing conjunctivitis. MAIN OUTCOME MEASURES: Direct immunofluorescence and direct immunoelectron microscopy without freezing on conjunctival and skin biopsy specimens, indirect immunofluorescence, Western immunoblot analysis. RESULTS: Results of direct immunoelectron microscopic examination of the conjunctiva showed the presence of immune deposits in the anchoring fibril zone, just beneath the lamina densa, in both patients. This finding was the same as the direct immunoelectron microscopic pattern shown in the skin of these patients, which is known to be very specific for EBA. Direct immunofluorescence was positive in the conjunctiva of only one patient. Indirect immunofluorescence and Western immunoblot analysis failed to detect circulating autoantibodies. CONCLUSIONS: Direct immunoelectron microscopy on the conjunctiva is a useful diagnostic tool to differentiate EBA from other related autoimmune mucocutaneous blistering diseases.     

Candidate vaccine antigens that stimulate the cellular immune response of mice vaccinated with irradiated cercariae of Schistosoma mansoni

Vaccination with radiation-attenuated cercariae confers the highest levels of resistance to challenge infection in experimental schistosomiasis and requires Ag-specific T cells. Therefore, this study aimed to identify specific Ag that stimulate the cellular immune response of mice vaccinated with irradiated cercariae of Schistosoma mansoni. Four experimental groups representing different levels of resistance in the vaccine model (C57BL/6J versus CBA/J mice vaccinated with 15- or 50-krad irradiated cercariae) were compared for in vitro lymphocyte proliferation and lymphokine production. Adult worm extracts fractionated by isoelectric focusing were used as Ag. Lymphocyte proliferation of all groups was limited to three consecutive isoelectric fractions (pH 4.6-6.3). Interestingly, the antibody response of these mice was directed to Ag in the same isoelectric fractions, three of which had previously been identified as paramyosin, heat shock protein 70, and the integral membrane protein Sm23. These Ag as well as two 28 kDa proteins, triosephosphate isomerase and glutathione S-transferase, in purified native or recombinant form or as a synthetic peptide, stimulated lymphocyte proliferation. Lymphocytes of vaccinated C57BL/6J mice generally showed higher levels of proliferation than did CBA/J mice. Interestingly, cells of once-vaccinated mice responded better than did cells of mice vaccinated three times. Lymphokine assays demonstrated that IL-2 and IL-4 was generally reduced after multiple vaccinations and varied qualitatively as well as quantitatively between mouse strains. This study substantiates that the five Ag, paramyosin, heat shock protein 70, triosephosphate isomerase, glutathione S-transferase, and the integral membrane protein Sm23, are important candidates for a defined antischistosomal vaccine.