CHARACTERIZATION, LOCALIZATION AND DISTRIBUTION OF alpha1 ADRENOCEPTOR SUBTYPE IN MALE RABBIT URETHRA

Purpose

The subtype specificity, localization and distribution of urethral alpha_{1-adrenoceptors} were studied in the male rabbit urethra.

Materials and Methods

The properties of the urethral alpha_{1-adrenoceptors} were investigated using radioligand receptor binding and light microscopic autoradiography with [(¹²⁵) I]iodo-2-[b-(4-hydroxyphenyl)-ethylaminomethyl]tetralone (HEAT), and immunohistochemistry with monoclonal anti-alpha smooth muscle actin and anti-alpha sarcomeric actin antibodies.

Results

Saturation experiments with [(¹²⁵) I]HEAT demonstrated the presence of significant amounts of a single high affinity binding site for alpha₁ adrenoceptors in the male rabbit urethra. The pharmacological profile of the alpha₁ adrenoceptors in rabbit urethra, determined by inhibition experiments with subtype selective alpha₁ adrenoceptor antagonists, was characterized by the following rank order of potency of inhibition constants (K_i values): prazosin <or= to WB 4101 < spiperone < 5-methylurapidil < BMY 7378. The pKi values for the rabbit urethra were correlated with the pKi values for rat spleen, submaxillary glands, and vas deferens and for those reported for cloned alpha_1d receptors with correlation coefficients of 0.68, 0.929, 0.909, and 0.523, respectively.

Conclusions

The pharmacological characterization demonstrates the predominance of alpha_1A or alpha_1A + alpha_1B adrenoceptor subtype(s) in male rabbit urethral smooth muscle. Furthermore, the autoradiographic and immunohistochemical studies show a heterogeneous distribution of alpha₁ adrenoceptors along the longitudinal axis of the urethra, within the smooth muscle fibers, with the receptors being localized more densely in the proximal than in the distal urethra.     

HAND ASSISTED LAPAROSCOPIC NEPHRECTOMY: COMPARISON TO STANDARD LAPAROSCOPIC NEPHRECTOMY

Purpose

We report our initial experience with hand assisted laparoscopic nephrectomy, and compare it to our results of standard laparoscopic nephrectomy.

Materials and Methods

The results of 21 hand assisted and standard laparoscopic nephrectomies (15 simple and 4 radical nephrectomies, and 2 nephroureterectomies) were reviewed. Hand assisted laparoscopic nephrectomy was performed with a hand placed intra-abdominally using the Pneumo Sleeve,^* in addition to standard laparoscopic instruments manipulated through laparoscopic ports. Standard laparoscopic nephrectomy was performed using laparoscopic instruments alone. Perioperative data were recorded and questionnaires, including visual analog pain scales, were administered prospectively to 17 of 21 cases.

Results

The average operative time for 13 hand assisted laparoscopic nephrectomies was 240 minutes, which was significantly less than the 325-minute average for 8 standard laparoscopic nephrectomies (p = 0.04). Major complications tended to be more frequent in the standard group (38 versus 8%, p = 0.10). Hospital stay, return to normal activity and corrected 2-week abdominal/flank pain score in the hand assisted group (3.1 days, 14 days and 0.8, respectively) were not significantly different from the standard group (3.0 days, 10 days and 0.2, respectively).

Conclusions

Compared to standard laparoscopic techniques, hand assistance appears to facilitate the operative speed and safety of laparoscopic nephrectomy without sacrificing the benefits of minimally invasive surgery. Hand assistance may make laparoscopic nephrectomy more appealing to urologists without advanced laparoscopic experience, may facilitate the laparoscopic management of demanding pathological conditions and is particularly useful when intact specimens are required. Hand assistance, by improving manipulative ability and tactile sense, is helpful for select cases of laparoscopic nephrectomy.     

The Effect of Dideoxycytidine on Lymphocyte Subpopulations in Nonhuman Primates

In the present study, 2',3'-dideoxycytidine (ddC), which hasantiretroviral activity, was given chronically to uninfectednonhuman primates to determine whether it produces adverse immunologicalor hematological effects. Nine healthy adult male rhesus monkeyswere divided into three groups and given the following dosesof ddC in a gelatin vehicle: group A, 0.06, 6.0, 3.0, and 1.5mg/kg; group B, 0.6 mg/kg; group C, 0 mg/kg. Blood samples werecollected for hematologic analysis and flow cytometric analysesof lymphocyte subpopulations. Chronic ddC exposure did not causesignificant changes in the number of red blood cells, monocytes,or reticulocytes. The number of white blood cells and neutrophilsincreased and these changes were observed only in group A animalsat the 1.5 mg/kg dose. The most significant alterations observedwere decreases in the number of T helper cells (CD4) and B cells(CD20). CD4⁺ and CD20⁺ lymphocytes exhibited dose-related shiftsthat were reversible over time and after drug withdrawal. Theresults indicate that ddC has few hematologic effects but itdoes have profound but transient effects on the number of cellsin lymphocyte subpopulations in normal primates.     

Abnormal prothrombin crossed-immunoelectrophoresis in patients with lupus inhibitors

Prothrombin deficiency has been known to occur in association with lupus inhibitors for over 25 years. We studied 21 patients with lupus inhibitors and found that four of five with prothrombin deficiency and ten of 16 with quantitatively normal prothrombin had abnormal prothrombin crossed-immunoelectrophoresis (CIEP) characterized by material moving slower in the first dimension of electrophoresis than normal prothrombin. In two patients with prothrombin deficiency, all prothrombin measured by quantitative assay and all slow-moving material on CIEP were removed by treatment with Staphylococcal protein A (SPA). These patients had free antibody, which bound to normal plasma prothrombin, forming larger amounts of slow-moving material on CIEP. A third patient with prothrombin deficiency had only partial removal of prothrombin after SPA treatment. Two patients with quantitatively normal prothrombin had all slow-moving material on CIEP and about one fourth of the prothrombin by quantitative assay removed by SPA treatment. There was no correlation among the strength of the inhibitor, the presence of a "cofactor effect," and the prothrombin abnormality. These data suggest that heterogeneous antiprothrombin antibodies, with or without prothrombin deficiency, are present in the majority of patients with lupus inhibitors.     

Inhibition of Leukotriene (SRS-A)-Mediated Acute Lung Anaphylaxis by Azelastine in Guinea Pigs

Azelastine hydrochloride, chemically known as 1(2H)-phthalazinone, 4-[(4-chlorophenyl)methyl]-2-(hexahydro-1-methyl-1H-azepine-4-yl)-, monohydrochloride, is a novel, orally effective, long-acting, antiallergic/antiasthmatic agent. The ability of azelastine and selected antiallergic drugs to inhibit SRS-A (leukotriene)-mediated acute lung anaphylaxis in guinea pigs (Konzett-Rossler method) was investigated. Azelastine and ketotifen were administered p.o. 2 and 24 h before antigen challenge; disodium cromoglycate (DSCG) was administered i.v. immediately before antigen challenge. The oral dose of azelastine required to inhibit leukotriene-mediated allergic bronchospasm by 50% (ID50: mg/kg) was 0.063 at 2 h and 0.120 at 24 h. Ketotifen at a dose of 0.05 to 10 mg/kg at 2 and 24 h, p.o., as well as DSCG at a dosage of 0.3 to 10 mg/kg at 0 min, i.v., produced weak, inconsistent and nondose-related antianaphylactic effects. Azelastine is an orally effective and long-acting inhibitor of in vivo synthesis and/or release of leukotrienes.     

Blood flow in “red” and “white” calf muscles in cats during isometric and isotonic exercise

Muscle blood flow was measured with the radioactive microspheres technique in plantar flexors of seven cats. Right leg performed rhythmic isotonic and left leg sustained isometric contractions. Flows were determined at rest, during stimulation periods, and immediately after 90 sec of high frequency stimulation. During isotonic contraction, flow to m. soleus (a “red muscle”) increased progressively as stimulation increased: 0.06±0.02, 0.21±0.05, 0.41±0.12, and 0.26±0.06 ml/min/g during rest, 10 Hz, 50 Hz, and after 50 Hz stimulation frequencies, respectively. Corresponding values for gastrocnemius medialis were 0.06±0.01, 0.38±0.05, 0.27±0.03, and 0.28±0.06 (x± S.E.). These last values were characteristic also for the other “white” muscles investigated: gastrocnemius lateralis, and plantaris. During sustained isometric exercise at 5 and 25 Hz stimulation frequency the patterns were similar, except that higher flows were observed, and during recovery flows actually increased again in the “white” muscles. Blood pressure did not change. Resting flows were similar in innervated and denervated muscles. These data demonstrate that during isotonic as well as isometric exercise there is an increased resistance to flow with increasing muscle tension in “white” but not in “red” muscles. This supports the notion that a condition of relative ischaemia exists in “white” muscles during both isometric and isotonic contractions which is more pronounced during isometric exercise. The results corroborate previous studies on isometric exercise and suggest that the pattern during isotonic exercise is similar.     

Improvement of the lymphoproliferative immune response and apoptosis inhibition upon in vitro treatment with zinc of peripheral blood mononuclear cells (PBMC) from HIV+ individuals

Clinical improvement has been described in AIDS patients submitted to zinc therapy, but the mechanisms involved are not well understood. In order to evaluate the effect of the zinc ions in the enhancement of the immune response, we tested its role in the lymphoproliferative response to a mitogen, as well as in the prevention of apoptosis. The mitogenic effect of zinc (10^?4 m ZnCl₂) on the lymphocyte proliferative response was observed in healthy controls as well as in HIV-1⁺ asymptomatic individuals. Very low stimulation index could be observed in AIDS patients (CD4⁺ < 200/mm³). However, zinc treatment of phytohaemagglutinin (PHA; 5 μg/ml)-stimulated PBMC cultures significantly enhanced ³H-thymidine incorporation in both asymptomatic and symptomatic groups. A decreased percentage of apoptotic cells could be identified in cell cultures from HIV-1⁺ individuals submitted to zinc treatment compared with cells treated only with PHA, as detected by both flow cytometry and agarose gel electrophoresis. Further studies with zinc supplementation associated to anti-retroviral therapy would be of great interest to evaluate the in vivo role of this oligoelement in the improvement of the immunological functions of HIV-1-infected individuals and AIDS patients.     

Boric acid susceptibility testing of non-C. albicans Candida and Saccharomyces cerevisiae: comparison of three methods.

To establish the best method for boric acid susceptibility testing, we compared two agar dilution methods (high and low inoculum) and a standard broth microdilution method (from the National Commitee for Clinical Laboratory Standards document NCCLS M-27A). Saccharomyces cerevisiae (37) and non-C. albicans Candida (39) isolates, as well as one isolate of Trichosporon sp., were included. All were isolated from female workers with vulvovaginitis. Good agreement within a fourfold dilution range was found between the three methods, and only the broth microdilution method versus the agar dilution method with high inoculum showed significant discrepancies. Reading results was easier with the broth microdilution method than with the agar dilution methods because of partial growth inhibition in the latter. In conclusion, broth microdilution is a suitable method for testing yeast susceptibility to boric acid.