The applicability of the flow cytometric sperm chromatin structure assay in epidemiological studies. Asclepios

The impact of demographic, lifestyle, and seminal factors on the sperm chromatin structure assay (SCSA) parameters was evaluated in a population of 277 healthy Danish men. This cohort was established within the framework of a European Concerted Action on occupational hazards to male reproductive capability in order to examine the possible reproductive effects of exposure to styrene or pesticides. The SCSA measures the susceptibility of sperm DNA to in-situ acid-induced denaturation, by multiparameter flow cytometric analysis after staining with the DNA-specific fluorescent dye acridine orange. The green versus red bivariate cytogram patterns were quite variable among donors, showing a wide heterogeneity of sperm DNA denaturability. Nevertheless, in those cases where we had the possibility to measure two semen samples from the same donor, the cytogram pattern remained stable over time (0.64 < r < 0.78). Analysis of variance demonstrated that the SCSA results can be influenced by the age of the donor (P < 0.0001), smoking habits (P < 0.05), the presence of leukocytes and immature germ forms in the ejaculate (P < 0.0001), and the duration of sexual abstinence (P < 0.0001). Furthermore, the relationship between the SCSA data and sperm concentration, morphology, and vitality was weak (-0.22 < r < -0.46). Therefore, the SCSA provides independent and complementary measurements of semen quality and is thus a useful tool for epidemiological studies, but the effects of some confounders should be accounted for in the survey design and analysis.     

Five-year survival in persons aged 40 years or over with newly diagnosed diabetes mellitus

The five- to six-year all-cause mortality is analysed in 1323 newly diagnosed diabetic patients aged 40 years or over. The median age at diagnosis is lower for males (63.6 years) than for females (67.5 years), but more males (24.7%) than females (20.0%) have died (p = 0.04). This male excess mortality can mainly be attributed to the 60-79-year old males. With increasing diabetes duration both male and female diabetic patients exhibit an increasing excess mortality in comparison with the Danish population. For males this excess mortality becomes statistically significant four years after diagnosis for the 40-59 year-olds and after six years for the 60-79 year-olds. For females and very old males no statistically significant excess mortality is observed, but after two to four years there is a tendency for the survival curve of 40-79-year old females to separate from that of the Danish female population to show an excess mortality. In this population-based study the disadvantageous mortality experience of even newly-diagnosed diabetic patients is clearly demonstrated.     

Diagnosis and management of colovesical fistulas

Diagnosis and management may present difficult problems in patients with colovesical fistulas. Symptoms in the urinary tract are most common, and cystoscopy, and cystography are the most valuable diagnostic procedures. It may not always be possible to demonstrate the fistula by diagnostic tests, and a high index of suspicion should be maintained in patients with inflammatory or neoplastic disease of the rectosigmoid area or bladder with recurrent cystitis. Definitive treatment should include resection of the fistula and diseased segment of the intestine. Both one stage and multistage procedures have their place in the treatment of this condition. There are specific criteria for success for a one stage procedure.     

Upper extremity replantation: current concepts and patient selection

Dramatic advances in replantation and microsurgery have somewhat altered the criteria we use in selecting patients to be candidates for upper extremity replantation surgery. We suggest that contraindications for such replantation are: presence of associated life-threatening injuries; serious anesthetic risk; preexisting medical or psychiatric problems; previous injury or disease of the amputated part; warm ischemic time greater than 6-8 hours for extremities or greater than 10-12 hours for digits; and single-digit amputations (except thumb, for grasp). Replantation is feasible when: amputated part is properly preserved; injury type is sharp amputation, mild to moderate crush, or selected avulsion, and amputation is proximal to the DIP joint. Careful preservation of the amputated part, not in dry ice, is mandatory. On an individual basis, the decision to attempt replantation rests on the prediction that the patient may have better function with such surgery than with a prosthesis.     

Limbic dysfunction in schizophrenia and mania. A study using 18F-labelled fluorodeoxyglucose and positron emission tomography

BACKGROUND: Diagnostic classes (derived from CATEGO) can be correlated with regional brain metabolism in patients with major psychiatric disorders. METHOD: Seventeen patients with schizophrenia, 15 with mania, 10 with depression and 10 healthy Volunteers were examined with positron emission tomography (PET) and 18F-labelled fluorodeoxyglucose, as a marker for glucose metabolism. The number of possible comparisons of regions of interest was reduced by principal-components analysis, and differences in factor scores were determined between diagnostic groups. RESULTS: Four independent factors, representing distributed brain systems, emerged: an anterior-posterior (1), a left-right temporal (2), a temporofrontal (3), and a mediofrontal (4) system, of which (1), (2) and (3) were abnormal in schizophrenia, (1) and (2) in mania, and (1) in depression. CONCLUSIONS: Abnormal patterns of metabolism could be detected, in decreasing order, in schizophrenia, mania and depression. Some of these abnormalities are likely to be due to medication, but others will be associated with structural or functional abnormalities of the frontolimbic system in the diagnostic groups.     

Vesicular transport: implications for cell polarity

In polarized cells intracellular sorting of plasma membrane proteins occurs to a large extent at the trans-Golgi network, giving rise to vesicles destined for distinct plasma membrane domains. This review discusses the several pathways, both direct and indirect, which lead to protein incorporation into the correct cell surface, as well as the mechanisms involved. Proteins contain signals which direct their incorporation into the distinct vesicles destined for plasma membrane microdomains. Specific coat proteins are involved in vesicle assembly and are likely to play a role in the generation of discrete vesicle populations. Molecules involved in vesicle docking and fusion may also add specificity to the targeting process.     

Cytochrome P450 3A4 activity in premenopausal and postmenopausal women, based on 6-beta-hydroxycortisol:cortisol ratios

STUDY OBJECTIVE: To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-beta-hydroxycortisol:cortisol ratio. DESIGN: Prospective study SUBJECTS: Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity INTERVENTIONS: Beginning on day 2 of menses, premenopausal women collected first morning urine samples every other day for a complete menstrual cycle. Postmenopausal women collected first morning urine every other day for 28 days. MEASUREMENTS AND MAIN RESULTS: Mean weekly 6-beta-hydroxycortisol:cortisol ratios did not differ during the phase (week) of the menstrual cycle. Daily ratios did not differ in postmenopausal women. No difference between premenopausal and postmenopausal women was found on comparing overall median ratios. CONCLUSION: Cytochrome P450 3A4 activity as measured by 6-beta-hydroxy cortisol:cortisol ratio did not differ by week of menstrual cycle, suggesting no menstrual cycle-related changes. Menopause does not appear to be associated with differences in CYP3A4 activity, compared with premenopause.     

SLIDE: subspace-based line detection

An analogy is made between each straight line in an image and a planar propagating wavefront impinging on an array of sensors so as to obtain a mathematical model exploited in recent high resolution methods for direction-of-arrival estimation in sensor array processing. The new so-called SLIDE (subspace-based line detection) algorithm then exploits the spatial coherence between the contributions of each line in different rows of the image to enhance and distinguish a signal subspace that is defined by the desired line parameters. SLIDE yields closed-form and high resolution estimates for line parameters, and its computational complexity and storage requirements are far less than those of the standard method of the Hough transform. If unknown a priori, the number of lines is also estimated in the proposed technique. The signal representation employed in this formulation is also generalized to handle grey-scale images as well. The technique has also been generalized to fitting planes in 3-D images. Some practical issues of the proposed technique are given     

Array algorithms for H∞ estimation

We develop array algorithms for H^∞ filtering. These algorithms can be regarded as the Krein space generalizations of H ² array algorithms, which are currently the preferred method fur implementing H² filters. The array algorithms considered include two main families: square-root array algorithms, which are typically numerically more stable than conventional ones, and fast array algorithms which, when the system is time-invariant, typically offer an order of magnitude reduction in the computational effort. Both have the interesting feature that one does not need to explicitly check for the positivity conditions required for the existence of H^∞ filters, as these conditions are built into the algorithms themselves. However, since H^∞ square-root algorithms predominantly use J-unitary transformations, rather than the unitary transformations required in the H² case, further investigation is needed to determine the numerical behavior of such algorithms     

Estimability and regulability of linear systems

A linear state-space system is said to be estimable if in estimating its state from its output the posterior error covariance matrix is strictly smaller than the prior covariance matrix. It is said to be regulatable if the quadratic cost of the state feedback control is strictly smaller than the cost when no feedback is used. Estimability and regulability are shown to be dual properties, equivalent to the nonreducibility of the Kalman filter and of the optimal linear quadratic regulator, respectively