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Biomedical subjects

R Viscuso

Publications and source records attributed to R Viscuso.

8 recordsLinked to original sources
PubMed2001

Role of male accessory glands in spermatodesm reorganization in Orthoptera Tettigonioidea.

A preliminary examination of the spermatodesms of Orthoptera Tettigonioidea revealed a structure that is similar in individuals of the same sex but very different in specimens of opposite sex. This reorganization would seem to take place inside the spermatophore during transit from the male to female genital tracts. The results of incubating spermatodesms with the secretions of glandular extract (GE) obtained from male accessory glands, known to be involved in forming the spermatophore wall, revealed changes in the spermatodesm 'cap' that are comparable to those occurring in vivo. Moreover, incubation of spermatodesms with the extracts obtained separately from tubules of the 1st and 2nd orders (GE1, GE2) established that GE2 alone modifies the spermatodesms, thus excluding the possible implication of 1st order tubules in the rearrangement process. In conclusion, data from incubations of spermatodesms with the single fractions obtained by submitting GE2 to gel-filtration FPLC show that only the peak 4 maintains intact the biological activity of GE2, SDS-PAGE analysis of the fraction corresponding to peak 4 revealed a greater protein content of 29 kD, which also appears to a lesser degree in fraction 3. This material is responsible for a partial dismantling of the 'cap' in the incubated spermatodesms.

Animals↗
PubMed1998

Potential interaction of troglitazone and cyclosporine.

BACKGROUND: Troglitazone (Rezulin) is a promising new oral hypoglycemic agent recently approved by the Federal Drug Administration for use in type II diabetes mellitus. Although troglitazone is not metabolized by the cytochrome p450 3A isozyme family, it is a potential inducer of this system. Other medications, e.g., rifampin and phenobarbital, which also induce p450 3A activity, have been reported to significantly decrease cyclosporine (CsA) concentrations. METHODS: We report a case of a stable renal transplant patient who had a decrease in CsA concentration after beginning troglitazone and who subsequently developed an acute rejection episode. We then reviewed all stable renal patients begun on troglitazone over the previous 6 months. RESULTS: The seven transplant patients who had been started on troglitazone therapy experienced a statistically and clinically significant decrease in CsA 12-hr trough levels immediately after the institution of troglitazone therapy. CONCLUSION: A potential interaction exists between troglitazone and CsA. Transplant patients on CsA who receive troglitazone therapy should be monitored closely.

Acute Disease↗
PubMed1996

Evaluation of voiding cystourethrography prior to renal transplantation.

In many centers, voiding cystourethrography is a routine part of pretransplantation assessment of the lower urinary tract. To assess the value of this investigation, a retrospective review of transplant candidates evaluated in our center over 2 years was undertaken. A total of 517 patients were fully evaluable. Only 13 voiding cystourethrograms (VCUGs) (2.5%) of 517 were found to be abnormal. Three patients with reflux alone did not require intervention before transplantation. Four patients with decreased bladder capacity underwent hydrodistention. Two patients increased their capacity to over 150 ml and two patients failed distention, one requiring an ileal conduit and the other requiring an augmentation cystoplasty. Three patients had increased postvoid residual (PVR). Two patients started clean intermittent catheterization. One required prostate resection for benign prostatic hypertrophy. One patient with reflux and decreased bladder capacity refused treatment. One patient with reflux combined with increased PVR started clean intermittent catheterization and was cleared for transplant surgery. One patient with decreased bladder capacity and increased PVR had a stroke and was excluded from transplantation. All 13 patients with abnormal VCUGs had a prior urologic history. In total, only 56 of 517 patients evaluated had a prior urological history. Each VCUG costs approximately $500. Limiting VCUG studies to those patients with a prior urological history would have resulted in a significant cost savings. Hence, we recommend that only patients with a prior urological history should undergo this costly and often distressing examination.

Adolescent↗
PubMed1996

Ultrastructural and histochemical characteristics of the lateral oviducts of Baculum thaii Haus. (Phasm.).

The wall of the lateral oviducts of baculum thaii is composed of a monolayered epithelium, lacking a cuticular intima, which lies on a sheath of striated muscular fibres. Untreated oviductal specimens exhibit two distinct regions. The anterior region, into which the various ovarioles emerge, is opalescent. The posterior region is more dilated and darker in colour. On the basis of the ultrastructural characteristics of the epithelial cells, four successive zones are definable for each oviduct. The first two zones comprise the most anterior oviductal area while the third and fourth comprise the posterior region. In zone 1 only is the oviductal wall composed of a single cell type. In addition, differences in structural organization between mated and virgin females were observed in this zone alone. In the three remaining zones, two distinct cell types were distinguishable according to two models of fundamental organization: cells having numerous apical microvilli and dome-shaped cells. The results of histochemical analyses established that the abundant secretory product elaborated by the epithelial cells is rich in both proteins and predominantly acidic mucosubstances. The histochemical characteristics of the secretory product differentiate significantly not only between the four zones in the same individual but also when the corresponding zones are compared in the mated and virgin females.

Animals↗
PubMed1990

Lectin binding to the egg envelopes in Eyprepocnemis plorans (Charp.) (Orthoptera, Acrididae).

The distribution of glycoconjugates in the egg envelopes of Eyprepocnemis plorans was investigated using various FITC-conjugated lectins. In the epichorion, the lectins ConA, SBA and WGA each have particular binding patterns, while TPA binding is confined to its deepest regions only. The glycoconjugates of the micropylar wall present different characteristics from those of the surrounding chorion. The vitelline coat shows a marked binding for WGA and TPA only; below the inner micropylar openings, this binding pattern is uniform over the whole extent of the coat and therefore it is not possible to identify specific binding sites for these two lectins. Contrary to what has been observed in some other insect species, the vitelline coat does not seem to be involved in the structural organization of the mycropyles.

Animals↗
PubMed1977

Anticipation of renal transplant failure by postanastomosis biopsy and immunofluorescence.

Ninety-six pre- and postanastomosis allograft biopsies from 48 transplant recipients were studied employing the direct fluorescent antibody procedure. Of the 48 transplants studied, 26 postanastomosis biopsies showed significant blood vessel wall deposits consisting predominantly of 2-4+ staining IgM and C3 deposits. The corresponding preanastomosis biopsies showed only patchy intimal surface staining. All but two of the grafts with positive biopsies had been preserved by the pulsatile perfusion method for various periods of time. Twenty-three of the twenty-six grafts with positive findings failed within 1 month while only 2 of the 19 negative postanastomosis biopsies failed within the 1-month period. Based on these findings actual graft failure occurred in 89% of the patients with postanastomosis transplant biopsies with positive findings. Although crossmatch studies were negative in all cases, further immunologic studies of eluates obtained from positive postanastomosis biopsies revealed the presence of lymphocytotoxic IgM antibodies in three of five cases studied. These findings suggest that rapid deposition of undetected preformed lymphocytotoxic antibodies accumulate in the vessel walls following anastomosis and contribute to transplant failure.

Biopsy↗