Histochemical observations on unique rod-like cells in the developing retina of the normal rat

Summary Our previous immunohistochemical studies using specific anti-opsin antibodies have shown that in the normal postnatal rat retina, opsin-like immunoreactive materials can be seen not only in photoreceptor cells but also in some cells of the inner nuclear layer (INL). To characterize these ectopic opsin-like immunoreactive cells further, we have now studied developing rat retinae at the light and electron microscopic levels using both opsin immunocytochemistry and 5-nucleotidase (5-N) cytochemistry. Since photoreceptor cells are specifically stained in both methods, we investigated whether these methods would also stain some of the cells in the INL. Opsin-like immunoreactive cells in the INL always showed a characteristic nuclear structure, which was clearly distinguished from that of other INL cells and resembled rod cell nucleus because of the presence of conspicuous masses of condensed heterochromatin. Moreover, these opsin-like immunoreactive cells in the INL occasionally also displayed a ciliary process. They could only be seen in the INL until about day 25 of postnatal life. In the INL, 5-N activity was found exclusively in cells showing rod-like nuclear features, and the timing of appearance and disappearance of 5-N-positive cells in the INL was similar to that of the opsin-like immunoreactive cells. Numerous degenerating cells were observed in the INL at around day 10, some of which showed 5-N reaction product at the cell surface. These results indicate that during postnatal development of the rat retina, some cells in the INL express several phenotypic properties characteristic of rod cells. It is suggested that these cells might undergo either cell degeneration or phenotypic conversion during the subsequent maturation of the retina.     

Effects of cyclophosphamide administration on the in vitro fertilization of mice

Purpose

To evaluate the oocyte fertilization ability and embryo growth after cyclophosphamide (CPA) treatment in mice.

Methods

Mice were treated with CPA at different doses (0‐800 mg/kg body weight). The oocytes then were retrieved and evaluated for their in vitro fertilization efficiency.

Results

The average number of metaphase II (MII) oocytes significantly decreased by ≥400 mg/kg CPA administration. The fertilization rate also decreased in the group that was treated with ≥400 mg/kg CPA. However, after fertilization, the embryos demonstrated normal growth ability. Two weeks after CPA administration, the number of mice from which the oocytes could be retrieved markedly decreased, but the fertilization rate and development of morphological features in the embryos were similar to those of the controls. One month after CPA administration, the number of mice from which the oocytes could be retrieved, fertilization rate, and development of the morphological features in the embryos were similar to those of the controls.

Conclusion

The number of oocytes decreased as the CPA administration level increased; however, the oocytes' potential for fertilization and development to the blastocyst stage was not significantly affected. One month after CPA administration, the number of oocytes and the potential for development into blastocysts were recovered.     

Functional heterogeneity of the descending limbs of Henle's loop

By using the in vitro microperfusion technique, were examined functions of the descending limbs of Henle's loop obtained from either the short-loop nephron (SDL) or the upper portion of the long-loop nephron of hamsters (LDLu). Morphological distinctions between these segments were confirmed by light and electron microscopic observations. Both segments were highly permeable to water. The LDLu was highly permeable to sodium and to chloride: efflux coefficients (10^–7 cm²·s^–1) for²²Na and³⁶Cl were 41.0±5.4 and 3.8±0.6, respectively. The SDL were less permeable to sodium and to chloride: efflux coefficient for²²Na and³⁶Cl were 2.9±1.4 and 0.9±0.2, respectively. In contrast, the SDL was more permeable to urea as compared to the LDL, efflux coefficients for urea being 5.1±1.4 vs 1.4±0.3, respectively. When composition of the perfusate was identical to that of the bathing fluid, no transepithelial voltage was demonstrated. The volume flux was very small or undetectable. From these observations, we propose that the internephron heterogencity must be taken into consideration for constructing a model of countercurrent system in the renal medulla.     

Successful delivery following intracytoplasmic sperm injection with calcium ionophore A23187 oocyte activation in a partially globozoospermic patient

Purpose

To describe a successful pregnancy outcome following intracytoplasmic sperm injection (ICSI) with assisted oocyte activation (AOA) in a case of partial globozoospermia.

Methods

AOA was accomplished with calcium ionophore A23187. Sperm morphology was observed via light, fluorescent and electron microscopy following a Diff-Quik stain and fluorescein isothiocyanate-labeled peanut agglutinin (FITC-PNA) staining. An activation ability test was employed using a mouse oocyte exposed to strontium chloride.

Results

Via light microscopy, it was found that a large number of sperm possessed deficient acrosomes and a sharply rounded head; however, we observed both normal and the aforementioned abnormal sperm via FITC-PNA staining of a semen specimen. Mouse oocyte activation was 87.5?% via natural activation without AOA. With AOA after ICSI, 100?% oocyte activation was observed. Five oocytes were retrieved, and AOA with A23187 after ICSI resulted in a high fertilization rate (4 of 5, 80?%). Two embryos developed and the patient subsequently delivered a healthy female infant without any congenital abnormalities.

Conclusions

We report a successful pregnancy outcome using an early stage embryo, which developed following ICSI using sperm from a partially globozoospermic patient who possessed temporary potential oocyte activation.     

Treatment with linezolid in a neonate with meningitis caused by methicillin-resistant Staphylococcus epidermidis

Recent findings have focused on the possible role of linezolid (LZD) as a suitable candidate for the treatment of central nervous system infections. LZD treatment for meningitis has been sporadically reported in adults, but there are no reports in neonates or infants. We report a case of meningitis caused by methicillin-resistant Staphylococcus epidermidis (MRSE) in a neonatal girl. The patient had intraventricular hemorrhage on postnatal day 1 and was treated with ventricular drainage. Twenty-two days after drainage, the patient developed a fever and seizure. Although ampicillin and ceftriaxone were given empirically for meningitis, an increased cell count and protein were observed in cerebrospinal fluid (CSF). Vancomycin (VCM) was administered intravenously because MRSE was detected from CSF 2 days after the administration of ampicillin and ceftriaxone. However, intravenous administration of VCM did not show any effect. Subsequent treatment of LZD successfully reduced the cell count and protein in CSF. Conclusion: LZD may be a treatment option for neonates and infants for drain-associated meningitis caused by MRSE.     

Conserved tRNA gene cluster in starfish mitochondrial DNA

Summary Partial sequencing of mtDNA from four long-diverged species of starfish reveals the existence of a conserved cluster of 13 tRNA genes, organized in a manner similar to that of the tRNA cluster of sea urchin mtDNA, but located at a position distant from the presumed replication origin. These findings suggest that a clustered organization of tRNA genes may have been present in the ancestral mitochondrial genome, and raise the possibility that tRNAs may have catalyzed the dispersal rather than the accumulation of the genes which encode them.     

Immunoallergological studies on chironomid antigen in bronchial asthma

Immuno-allergological studies on Tokunagayusurika akamusi (TA), a chironomid, were carried out in 217 patients with bronchial asthma. 1. Skin reaction to TA was positive in 72 (33.2%) out of the 217 patients with bronchial asthma. 2. Fifteen (13.8%) of the 109 patients showed a significant amount of histamine release (more than 15%) from basophils stimulated by TA antigen. 3. There was a significant correlation between skin reaction and histamine release by TA antigen. 4. A significant amount of basophil histamine release was observed in young patients, and in those who were under 40 years old of age at the onset of the disease. The serum IgE concentration of these patients was relatively high. 5. There was a significant correlation between basophil histamine release by TA antigen and specific IgE antibody to CTT. 6. There were no significant differences in skin reaction or histamine release by TA antigen between asthmatics in Okayama and Tottori prefectures.