The nature of human orgasm: a critical review of major trends

This critical review presents a synthesis of the available theoretical and empirical literatures on human orgasm. Findings from both normal and clinical human populations are included. Two major trends in the literature, the dichotomization of biological and psychological perspectives and the assumption of gender differences, are highlighted. A new multidimensional model of the psychological experience of orgasm is described with a view to futhering a biopsychological approach applicable to both sexes. Clinical applications of this new model are discussed.     

Differential effects of oltipraz on CYP1A and CYP2B in rat lung

Oltipraz (OPZ) is a potent chemopreventive agent against chemically-induced carcinogenesis in several animal models. It affects the expression and/or activity of xenobiotic-metabolizing enzymes and its effects are altered in the course of inflammation in liver. The present study was undertaken to analyse the effect of OPZ alone or in combination with Escherichia coli lipopolysaccharide (LPS) on the expression and activities of glutathione S-transferases (GSTs) and cytochrome P450 (CYPs) in rat lung and kidney. Male Wistar rats were fed a diet containing OPZ for 1-5 days. LPS was injected 24 h before the end of OPZ treatment (from 48 to 72 h). Total GST activity, measured using 1-chloro-2,4-dinitrobenzene as a substrate, increased slightly in both lung and kidney during OPZ treatment. As previously demonstrated in the liver, OPZ induced rat GSTP1 in both kidney and lung and this effect was totally (kidney) or partially (lung) inhibited by co-treatment with LPS. CYP1A expression and activity were strongly increased in both tissues 24 h after starting OPZ treatment and maintained for 5 days. This increase was suppressed during the acute-phase response to endotoxin. OPZ has no effect on CYP2B1 mRNA expression in the lung, but it dramatically decreased the amount and activity of the corresponding apoprotein. The OPZ-dependent decrease in the CYP2B1 apoprotein was abolished and its corresponding activity partially reversed during LPS treatment. In reconstitution experiments using cytosol from OPZ-treated or control rat lungs and microsomal fractions, CYP2B1 apoprotein was rapidly degraded in the presence of cytosol from treated rats. This effect was partially reversed in the presence of MG132, a proteasome inhibitor. These observations support the conclusion that the decrease of CYP2B1 by OPZ involves proteasome-dependent degradation and represents a new mechanism of regulation by this compound.     

Dietary fat, body weight, and cancer: contributions of studies in rodents to understanding these cancer risk factors in humans

Understanding diet and energy balance as risk factors for breast, colon, and other cancers requires information on the contribution of each factor and of interactions among factors to cancer risk. Rodent models for breast cancer provide extensive data on effects of dietary fat and calories, energy balance, body weight gain, and physical activity on tumor development. Analyses of the combined data from many studies have shown clearly that quality and quantity of dietary fat and energy balance contribute independently to increased mammary gland tumorigenesis. These findings were seen in female rats fed diets high in fat (35-40% of calories) compared to rats fed control diets, with approximately 10% of calories as fat (Fay and Freedman, 1997, Breast Cancer Res. Treat. 46, 215-223). The methods used permit comparison of experimental and epidemiological data, and they may be useful in extrapolating between species and developing public health recommendations. In addition to the contributions of lifetime-diet composition, intake, energy balance, and physical activity to cancer risk, there are questions about the timing and duration of alterations in these factors and about the "dose-response" characteristics of cancer risk to the factors. Endocrine mechanisms may be significant in mammary gland tumor risk, but experimental and epidemiological data indicate that cancers at other sites, such as colon and liver, also are influenced by the factors listed. Other diet and lifestyle factors that influence energy, or specifically fat, metabolism may also affect risk for cancers that are promoted by increased intake of fat and calories. Studies of separate and interactive effects of dietary fat, black tea, weight gain, and mammary gland tumorigenesis (Rogers, et al, 1998, Carcinogenesis 19, 1269-1273) have been analyzed. Using adjustment of carcinogenesis endpoints for body weight, tumor burden, and latency, they were found to be related to weight gain within treatment groups in 2 of 3 experiments.      

Diagnosis of tuberculous peritonitis

The diagnosis of tuberculous peritonitis may be difficult and elusive. The patient may present with non-specific symptoms of fever, general ill-health or vague abdominal pains. There may be no pulmonary symptoms and the chest X-ray may be normal. The CT scan of the abdomen is sometimes helpful in suggesting the diagnosis. We have found that laparoscopic examination of the abdominal contents and the peritoneum is an effective way to obtain a conclusive diagnosis.     

Urea rebound and delivered Kt/V determination with a continuous urea sensor

BACKGROUND: The recent introduction of urea sensors for dialysis monitoring has made possible new approaches to urea kinetic modelling. In this study we show how the equilibrated postdialysis urea concentration (Ceq) and Kt/V corrected for double-pool urea kinetics (Kt/Vdp) can be accurately determined using an on-line sensor providing a continuous measure of blood water urea. A modification of the Smye constant volume double-pool theory led to the following equations for Ceq and Kt/Vdp [formula: see text] where Cpre is the blood concentration measured at the start of dialysis, t is the length of the dialysis session (in min) and S(ex) is the constant slope of the blood urea logarithm concentration decline following development of the intercompartmental urea concentration gradient in the first 30-60 min of dialysis. METHODS: These equations were tested in 11 patients undergoing 165-240 min of paired filtration dialysis with continuous monitoring of blood urea concentration. Cpre was determined as the plateau concentration during a preliminary period of 15-20 min of slow isolated ultrafiltration. S(ex) was accurately determined from linear regression applied to the urea sensor data from the 80-min point to the end of dialysis. RESULTS: Ceq and Kt/Vdp determined from the above equations compared closely to values determined from 25-40 min of urea rebound monitoring with the urea sensor: 10.6 +/- 3.0 versus 10.8 +/- 2.7 mmol/l (mean +/- SD) for Ceq and 1.21 +/- 0.24 versus 1.18 +/- 0.20 for Kt/Vdp, compared to single-pool values of Kt/V = 1.34 +/- 0.23. CONCLUSION: This technique may be readily programmed into on-line urea monitors to provide current and extrapolated values of Ceq and Kt/Vdp from about the first hour of dialysis.