Basic fibroblast growth factor enhances in vitro mineralization of rat bone marrow stromal cells grown on non-woven hyaluronic acid based polymer scaffold.

A biodegradable non-woven hyaluronic acid polymer scaffold (Hyaff 11) was analysed in vitro as a carrier vehicle for differentiation and mineralization of rat bone marrow stromal cells (BMSC). BMSC were grown on Hyaff 11 in a mineralizing medium in the presence/absence of basic fibroblast growth factor (bFGF). Osteoblastic differentiation was investigated by light and electron microscopy analysing the expression of osteogenic markers: calcium, alkaline phosphatase (AP), osteopontin (OP), bone sialoprotein (BSP) and collagen type 1. We also measured proliferation, AP activity and mRNA expression of AP and osteocalcin (OC). Electron microscopy and Toluidine-blue staining demonstrated that bFGF accelerated (day 20 vs. day 40) and increased mineralization. With bFGF, calcium, OP and BSP were strongly enhanced at day 40, whereas AP decreased. Our in vitro results demonstrate that Hyaff 11 is a useful vehicle for growth, differentiation and mineralization of rat BMSC, and that it permits bone development.

Development of temporal properties of pattern electroretinogram and visual evoked potentials in infants.

The postnatal development of the temporal properties of the responses to pattern contrast reversal has been studied by recording simultaneously the pattern electroretinogram (PERG) and visual evoked potentials (PVEP) in infants 3-22 weeks old. The stimulus grating (0.5 c/deg) was either reversed in contrast sinusoidally at frequencies 4-10.5 Hz to study the temporal frequency function of steady-state responses, or square-wave reversed at 1 Hz to evaluate the peak latency of transient responses. Developmental changes of the shape and bandwidth of the temporal frequency function of both PERG and PVEP occur post-natally and are particularly pronounced between 13 and 20 weeks from birth, possibly indicating deferred maturation of classes of retinal and central neurons with higher temporal resolution. The peak latency of the PERG decreases during the age period tested to approach adult values towards the end of the fifth month. The rate of decrease of the peak latency of the PERG differs from that of the PVEP, indicating that post-retinal factors contribute largely to the maturation of the latter, especially in the earliest life period.

Experimentally induced rabies in four cats inoculated with a rabies virus isolated from a bat.

Four cats were inoculated IM with rabies virus isolated from the salivary gland of a naturally infected big brown bat (Eptesicus fuscus). The 4 cats developed clinical signs of rabies after a median incubation period of 42 days. The median duration of clinical illness was 5 days. Results of fluorescent antibody evaluation, mouse inoculation, and tissue culture isolation indicated large differences in virus concentrations in various areas of the CNS of individual cats. These differences also were observed between cats. Rabies virus was isolated from the salivary glands and saliva of 2 cats; urinary bladder was the only other nonneural tissue found infected. Our observations indicated that cat rabies can be caused by bat rabies virus; that cats thus infected have infectious saliva during aggressive behavior and can therefore transmit the disease; and that adequate specimens of hippocampus, cerebellum, and brain stem are essential for reliable determination of rabies infection. The findings support recommendations for regular rabies vaccination of cats, even in areas of rabies-free terrestrial mammals.

Naturally occurring rabies virus and neutralizing antibody in two species of insectivorous bats of new york state.

Seven colonies of Eptesicus fuscus , the big brown bat, and five colonies of Myotis lucifugus , the little brown bat, in New York State were sampled for rabies virus and virus-neutralizing antibody. Eight of 278 E. fuscus were found to have virus, while 18 of 187 had antibody titers of ≥1:8. One of 333 M. lucifugus yielded virus, while three of 127 had antibody. These data demonstrate the presence of rabies virus as well as immunity to rabies in some insectivorous bats of New York State. Evaluation of these findings in relation to the epizootiology of the disease in bats requires further investigation.

Pantropism of rabies virus in free-ranging rabid red fox Vulpes fulva.

The fluorescent antibody and mouse inoculation tests were employed to study the pantropism of rabies virus in tissue from free-ranging red fox (Vulpes fulva) submitted for rabies diagnosis. Viral antigen was found in various organs and tissues of the body. The distribution of antigen within tissues is discussed in the light of the pathogenesis and potential excretion of the virus.

A micromethod for measuring rabies-neutralizing antibody.

Plasma samples collected in micro-hematocrit tubes were shown to have rabies-neutralizing antibody titers comparable to serum samples. Micro-hematocrit tube sampling makes possible the monitoring of antibody levels in very small animals without causing serious injury.

[Clinical considerations on spontaneous pneumothorax]. / Considerazioni cliniche sul pneumotorace spontaneo.

The authors, after confirming the social interest of spontaneous pneumothorax, report the results of their experience taking hint from it for some clinical considerations. They mention different therapies suggested for the treatment of this disease; particularly they dwell upon aspiration techniques considered today the treatment of choice in most cases. They conclude affirming that this technique improves results, diminishes risks and complications, and considerably reduces hospitalization.

Visual performance in behaving cats after prenatal unilateral enucleation.

Prenatal unilateral enucleation in mammals causes an extensive anatomical reorganization of visual pathways. The remaining eye innervates the entire extent of visual subcortical and cortical areas. Electrophysiological recordings have shown that the retino-geniculate connections are retinotopically organized and geniculate neurones have normal receptive field properties. In area 17 all neurons respond to stimulation of the remaining eye and retinotopy, orientation columns, and direction selectivity are maintained. The only detectable change is a reduction in receptive field size. Are these changes reflected in the visual behavior? We studied visual performance in cats unilaterally enucleated 3 weeks before birth (gestational age at enucleation, 39-42 days). We tested behaviorally the development of visual acuity and, in the adult, the extension of the visual field and the contrast sensitivity. We found no difference between prenatal monocularly enucleated cats and controls in their ability to orient to targets in different positions of the visual field or in their visual acuity (at any age). The major difference between enucleated and control animals was in contrast sensitivity:prenatal enucleated cats present a loss in sensitivity for gratings of low spatial frequency (below 0.5 cycle per degree) as well as a slight increase in sensitivity at middle frequencies. We conclude that prenatal unilateral enucleation causes a selective change in the spatial performance of the remaining eye. We suggest that this change is the result of a reduction in the number of neurones with large receptive fields, possibly due to a severe impairment of the Y system.

Development and evaluation of an in vitro virus isolation procedure as a replacement for the mouse inoculation test in rabies diagnosis.

A tissue culture virus isolation procedure for rabies street strain virus on mouse neuroblastoma cells is described. Parameters for the optimum sensitivity of the procedure were determined to include a minimum 4-day incubation of virus in tissue culture and the use of diethylaminoethyl-dextran for increased cell susceptibility. The in vitro procedure performed well in a comparison with the fluorescent-antibody test and the mouse inoculation test (MIT) on weakly positive brain tissue. Decomposed specimens and virus inhibitors present in brain suspensions were found to interfere with the in vitro procedure. A Formalin-methanol fixative was found to be superior on plastic 96-well plates to previously used fixatives. A 2-year clinical trial of the procedure in parallel with the MIT demonstrated the practicality of the procedure. Accordingly, the New York State rabies diagnostic laboratory has replaced the MIT with the in vitro procedure as a backup for the fluorescent-antibody test in the routine diagnosis of rabies.

Production of rabies fluorescent conjugate by immunization of rabbits with purified rabies antigen.

Fluorescein-labelled antirabies virus conjugate was produced by hyperimmunizing rabbits with a purified rabies virus (CVS-27). The conjugate had a working dilution of >/=1: 500 in the rabies fluorescent antibody test. Stability under lyophilization was satisfactory.

Comparison of sensitivity of BHK-21 and murine neuroblastoma cells in the isolation of a street strain rabies virus.

The sensitivities of BHK-21 (C-13) and murine neuroblastoma (C-1300; clone NA) cells for the isolation of small quantities of a street strain rabies virus were compared. Suspensions of brain from mice sacrificed prior to the onset of clinical signs of rabies were used to stimulate weakly positive diagnostic specimens. The results of cell culture isolation were compared with those of the direct fluorescent-antibody test and virus isolation in weanling mice. Neuroblastoma cells were more sensitive to the street strain rabies virus than were BHK-21 cells. Neuroblastoma cell virus isolation, the mouse inoculation test, and the fluorescent-antibody test all showed comparable sensitivity.

Dopaminergic mechanisms underlying the reduction of electrical coupling between horizontal cells of the turtle retina induced by d-amphetamine, bicuculline, and veratridine.

Previous studies have shown that dopamine, bicuculline, or d-amphetamine reduce the electrical and dye-coupling between the axon terminals of the horizontal cells of the turtle retina (see Piccolino et al., 1984). In the present study we observed similar effects following the application of veratridine. The actions of all these drugs were prevented by dopamine antagonists acting on D1 receptors such as flupenthixol and SCH 23390. However, in contrast to dopamine, the actions of d-amphetamine, bicuculline, and veratridine were attenuated or abolished by pharmacological agents (such as 6-OH-dopamine, alpha-methyl-p-tyrosine, or reserpine) known to reduce the release of dopamine from dopaminergic neurons. Moreover, the actions of veratridine and bicuculline were prevented by tetrodotoxin, indicating that one or more neurons in the dopamine pathway are spike-generating. We conclude that d-amphetamine, bicuculline, and veratridine reduce electrical coupling between the axon terminals of the turtle horizontal cells by promoting the release of endogenous dopamine from the dopaminergic amacrine cells previously identified (Witkovsky et al., 1984). Electron-microscopic observations revealed that 6-OH-dopamine selectively attacked this population of amacrine cells. No degenerating terminals were found adjacent to the horizontal cell axon terminals. On this basis, we postulate that dopamine reaches the horizontal cell by diffusion through the extracellular space.

Cyclic estrogen-progestin hormone therapy as a new therapeutic approach in the treatment of functional alterations of the hypothalamus-pituitary-ovary axis: case reports.

Amenorrhea is a clinical condition characterized by failure of menarche or by the absence of menstruation for six months in a woman with previous periodic menses. We report a first case of a 30 year-old woman affected by polycystic ovarian disease (PCOD) whose amenorrhea ceased after a 6-month combination treatment with cyclic estradiol-norethisterone acetate. After the withdrawal of the hormone therapy, a stable recovery of periodic menses was observed. We describe a second case of a 23 year-old woman whose amenorrhea was caused by a hypogonadotropic hypogonadism due to a non-functioning pituitary adenoma. After the administration of the previously described therapy both a disappearance of the adenoma and a recover of periodic menses were observed. We hypothesized that the outcomes in our cases could be the consequence of a balancing action induced by the exogenous hormone administration. The exogenous hormones may have reset the feedback between the hypothalamus and pituitary gland through mimicking the physiological hormones pattern of the 28-day cycle.

Prenatal monocular enucleation induces a selective loss of low-spatial-frequency cortical responses to the remaining eye.

During early development, interactions between the two eyes are critical in the formation of eye-specific domains within the lateral geniculate nucleus and the visual cortex. When monocular enucleation is done early in prenatal life, it induces remarkable anatomical and functional reorganizations of the visual pathways. Behavioral data have shown a loss in sensitivity to low-spatial-frequency gratings in cats. To correlate the behavioral observations with a possible change in the analysis of contrast at the level of primary visual areas we recorded visual evoked potentials at the 17/18 border in two cats enucleated prenatally (gestational age at enucleation, 39-42 days), three neonatal, two control animals, and one animal with a surgical removal of Y-ganglion fibers. Our results show a strong attenuation in the amplitude of response at all contrast values for gratings of low spatial frequency in prenatally enucleated cats, whereas neonatally enucleated and control animals present responses of comparable amplitude. We conclude that the behavioral results reflect the reduced sensitivity for low frequencies of visual cortical neurons. In addition, we define a critical period for the development of the contrast-sensitivity function that seems to be limited to the prenatal gestation period. We suggest that the prenatal interruption of binocular interactions leads to a functional elimination of the Y-ganglion system.

Standardization and quantitation of immunofluorescence in the rabies fluorescent-antibody test.

The standardization and quantitation of immunofluorescence with a Farrand microphotometer in the rabies fluorescent-antibody technique were determined. The system is useful in maintaining the quality of examinations for rabies in a public health laboratory since quantitation of reagent, equipment performance, and specificity of reaction can be evaluated. An analysis of the results demonstrates the high degree of reproducibility and the accuracy of the techniques described.

Tissue culture technique for routine isolation of street strain rabies virus.

A tissue culture test for the primary isolation of street strain rabies virus from the brains of suspect animals was evaluated. It was found to be reliable and comparable in sensitivity to the standard mouse inoculation technique. The test, which yields final results in 48 h, was performed in BHK-21 cells on tissue culture chamber slides. The addition of diethylaminoethyl dextran to the cell suspension before seeding the slide promoted the subsequent viral invasiveness of positive test specimens. The method described may be considered as a substitute for the mouse inoculation test which is currently used as a backup to the fluorescent antibody test in the diagnosis of rabies.

The epidemiology of bat rabies in New York State, 1988-92.

In 1993 New York and Texas each reported a human rabies case traced to a rare variant of rabies virus found in an uncommon species of bat. This study examined the epidemiology of bat rabies in New York State. Demographic, species, and animal-contact information for bats submitted for rabies testing from 1988-92 was analysed. The prevalence of rabies in 6810 bats was 4.6%. Nearly 90% of the 308 rabid bats identified to species were the common big brown bat (Eptesicus fuscus), which comprised 62% of all submissions. Only 25 submissions were silver-haired bats (Lasionycterus noctivagans), the species associated with the two 1993 human cases of rabies, and only two of these bats were positive. Rabies was most prevalent in female bats, in bats submitted because of human [corrected] contact, and in animals tested during September and October. These results highlight the unusual circumstances surrounding the recent human rabies cases in the United States. A species of bat rarely encountered by humans, and contributing little to the total rabies cases in bats, has been implicated in the majority of the indigenously acquired human rabies cases in the United States. The factors contributing to the transmission of this rare rabies variant remain unclear.