Effects of chronic partial outlet obstruction on blood flow and oxygenation of the rat bladder

PURPOSE: Experimental partial bladder outlet obstruction in rats and rabbits drives the bladder through 3 sequential responses, referred to as hypertrophy, compensation and decompensation. The hypertrophy phase, which is a period of rapid bladder growth, has previously been shown to be accompanied by a significant increase in bladder blood flow in rats and rabbits in a manner that likely supports the bladder cell growth process. However, chronic periods of obstruction in the rabbit have been shown to reduce significantly bladder blood flow, especially to the detrusor smooth muscle, corresponding with a loss of bladder contractile function or decompensation in these animals. We determined the effects of chronic 1 to 4-week partial outlet obstruction on rat bladder blood flow and directly correlated them with hypoxia in the rat bladder. MATERIALS AND METHODS: Rats underwent surgical partial bladder outlet obstruction under anesthesia. At weekly intervals after surgery relative blood flow to the bladder and spleen was measured by a fluorescent microsphere infusion technique. Sham operated rats were also studied 2 and 4 weeks following surgery. In a second experiment groups of similarly obstructed rats were treated with Hypoxyprobe-1 (Natural Pharmacia International, Inc., Research Triangle Park, North Carolina), a chemical probe for hypoxia, 3 days, 1 and 2 weeks after partial bladder outlet obstruction. The bladders were subsequently fixed and immunostained using a monoclonal antibody that detects Hypoxyprobe-1 adducts that are selectively formed in hypoxic cells. RESULTS: Neither bladder weight nor bladder relative blood flow was affected by sham surgery. Likewise, control and sham obstructed rat bladders were found to be free of Hypoxyprobe-1 reactive areas. In contrast, obstructed rats had significantly increased bladder weight at all time points. Relative weight of the obstructed rat bladders indicates the response to mild-moderate obstruction. Bladder relative blood flow in obstructed rats was significantly elevated 1 and 2 weeks after partial bladder outlet obstruction but it returned to almost control levels by 3 and 4 weeks. Hypoxyprobe-1 staining demonstrated a sequential transition of hypoxia from bladder mucosa and submucosal regions at 3 days to muscularis and serosal fibroblasts 1 week and finally to smooth muscle cells by 2 weeks after obstruction. CONCLUSIONS: In contrast to the rabbit model, global blood flow in the mild-moderate chronically obstructed rat bladder was found to be higher or nearly equivalent to blood flow in unobstructed control rat bladders. However, even in the presence of normal or above normal blood flow focal regions of hypoxia were still observed in obstructed rat bladders and these regions changed with time. These results provide a reason to understand better why rats are more resistant to the onset of bladder decompensation than rabbits and support the concept that hypoxia is involved in bladder remodeling as well as in progressive functional impairment of the bladder after partial bladder outlet obstruction.     

Fragmentation of uric acid calculi with the holmium: YAG laser produces cyanide

BACKGROUND AND OBJECTIVES: To independently test previously reported findings of cyanide evolution under holmium:yttrium aluminum garnet (Ho:YAG) (holmium) lithotripsy of uric acid calculi, determine if this occurs with other forms of intracorporeal lithotripsy, and establish if this occurs due to a photothermal, photochemical, or photoacoustic reaction. STUDY DESIGN/MATERIALS AND METHODS: Human uric acid calculi were fragmented in vitro through exposure to holmium, ultrasound, and electrohydraulic (EHL) energy sources. The following parameters were varied: total laser energy, individual laser pulse energy, ultrasonic energies, and EHL energies. Uric acid powder was suspended in solution and exposed to holmium laser energy in vitro. Serum and irrigant samples from a human patient were collected following intrarenal holmium lithotripsy of a uric acid calculus. All samples were analyzed for hydrogen cyanide (HCN) content. RESULTS: Holmium lithotripsy of solid uric acid calculi produces cyanide. The yield is linearly dependent upon total laser energy delivered. Pulse energy does not affect cyanide yield. Photothermal mechanisms coupling laser energy to the solid crystal lattice are responsible for the production of cyanide. Ultrasound and EHL lithotripsy do not produce cyanide. A clinically insignificant level of cyanide was detected in the blood of a single patient following laser lithotripsy of a uric acid calculus. CONCLUSIONS: Our study confirms that cyanide is produced by a photothermal mechanism during holmium laser lithotripsy of uric acid calculi, and that the amount produced is clinically insignificant.     

Gender, alcohol consumption, and renal cell carcinoma

The nature of the association between alcohol consumption and renal cell carcinoma (RCC) is not well understood, but there are indications of effect modification by gender. The authors report data from a population-based case-control study conducted in Iowa from 1986 to 1989. RCC cases (261 men and 145 women) were identified through the Iowa Cancer Registry, while controls (1,598 men and 831 women) were randomly selected from the general population, frequency matched on age and gender. Subjects provided detailed information on a mailed questionnaire regarding demographic, anthropometric, lifestyle, dietary, and medical history risk factors. In age-adjusted analysis, there was a decrease in risk for women who reported consuming more than three servings (median among drinkers) of alcohol per week (odds ratio = 0.5, 95% confidence interval: 0.2, 0.9) compared with never drinkers. No evidence of an association among men was noted (odds ratio = 1.1, 95% confidence interval: 0.8, 1.5). Multivariate adjustment for anthropometric, lifestyle, smoking, and dietary factors did not alter the findings. Analysis by type of alcohol suggested that the inverse association was strongest for beer consumption, but estimates were imprecise. These findings suggest an inverse association of alcohol consumption and RCC development among women but not among men.     

Telephone-assisted counseling for physical activity

Different methods of intervention have been tested to promote physical activity at the individual level. The telephone is an excellent form of media for delivering exercise counseling and advice. This review highlights important clinical trials that have documented the success of telephone-assisted exercise counseling for promoting physical activity in a variety of populations.     

Lack of HIV Seropositivity Among a Group of Rural Probationers: Explanatory Factors

CONTEXT: Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) in rural America has been described as an epidemic, and the HIV prevalence rate among criminal justice populations is higher than the general population. Thus, criminally involved populations in Southern rural areas are at elevated risk for contracting HIV because of drug and sexual practices; however, little is known about HIV/AIDS in the fastest growing criminal justice population-probationers. PURPOSE: To examine possible explanations for the lack of HIV seropositivity found in a purposive sample of rural probationers. METHODS: Data were examined from 800 felony probationers from 30 counties in Kentucky's Appalachian region. Measures included HIV prevalence within the 30 counties, migration patterns, HIV knowledge, substance use, and sexual risk behaviors. FINDINGS: These probationers had a high level of HIV knowledge, reported minimal injection drug use, practiced serial monogamy, and reported minimal engagement in transactional sex. However, these probationers also reported negligible condom use, and injection drug users shared needles and works. CONCLUSION: Findings suggest the importance of developing programs targeting safe sex practices in rural areas.     

Generation of cytotoxic antibodies to the B16 murine melanoma using a formalinized vaccine

The goal of our experiments was to determine the extent to which the humoral response to a melanoma vaccine elicits the production of cytotoxic antibodies in tumor-challenged mice. Mice were immunized with a vaccine produced from formalinized extracellular antigens (FECA) derived from B 16 F 10 melanomas. The production of antibodies that recognized the vaccine preparation was determined by ELISA, as was their cross-reactivity with the B700 melanoma,antigen. The antibodies were shown to be anti-proliferative by inhibition of tritiated thymidine incorporation into the DNA of cultured target cells and cytotoxic by assays for complement-mediated and antibodydependent cellular cytotoxicity. Flow cytometric analyses indicated that-60% of the target cells specifically bound antibody from the immune sera. These results confirm that B700 is a significant antigenic component of the FECA vaccine, and provide encouragement for this approach to developing useful melanoma vaccines.     

Effects of the polycyclic aromatic hydrocarbon heterocycles, carbazole and dibenzothiophene, on in vivo and in vitro CYP1A activity and polycyclic aromatic hydrocarbon-derived embryonic deformities

Heterocyclic derivatives of polycyclic aromatic hydrocarbons (PAHs) are often significant components of environmental contaminant mixtures; however, their contribution to the toxicity of these mixtures is not well characterized. These heterocycles commonly co-occur in PAH mixtures, which contain agonists for the aryl hydrocarbon receptor (AHR). Our goal for these studies was to explore the effects of two PAH heterocycles, carbazole (CB) and dibenzothiophene (DBT), alone and in combination with a PAH-type agonist for the AHR (beta-naphthoflavone [BNF]) on AHR-mediated cytochrome P4501A (CYP1A) activity and on fish embryotoxicity. Embryos of Fundulus heteroclitus were exposed to CB or DBT, with and without coexposure to BNE Carbazole alone slightly induced, whereas DBT alone slightly reduced, in ovo CYP1A-mediated ethoxyresorufin-O-deethylase (EROD) activity compared to control values. However, exposure to CB or DBT reduced in ovo EROD activity in embryos coexposed to BNE Carbazole and DBT were characterized in vitro as noncompetitive CYP1A inhibitors. Carbazole and DBT enhanced the embryotoxicity of BNF, although neither compound was embryotoxic by itself. The co-occurrence of CB and DBT with PAH-type AHR inducers in contaminated ecosystems may increase the toxicity of PAH-type AHR agonists in these settings and may need to be considered when estimating the embryotoxicity of PAH mixtures.     

Gallbladder pathology in the Ivory Coast. Contribution of ultrasonics

Ultrasound imaging was first used in the two hospital and university centers of Abidjan in 1983, and findings since then have demonstrated the previously unrecognized frequency and variability of gallbladder affections. Particular conditions of functioning of an ultrasonography department in tropical surroundings are analyzed and ultrasound features of bile stones, cholecystitis and gallbladder cancer described.