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Biomedical subjects

S Shapiro

Publications and source records attributed to S Shapiro.

At least 199 records · Page 11Linked to original sources
PubMed1994

The relation of vasectomy to the risk of cancer.

We previously reported a strong positive association between vasectomy and the risk of prostatic cancer that arose in multiple comparisons made within data collected from 1976 to 1988 in an ongoing hospital-based surveillance study of many exposures and diseases. We have reassessed this association with data collected in the surveillance study during 1988-1992 from a new set of patients (355 cases of prostatic cancer and 2,048 controls with nonmalignant conditions). Because some studies have reported increased relative risks of lung cancer and testicular cancer in vasectomized men, we also used the surveillance database (4,126 men with various cancers, 7,027 men with nonmalignant conditions) to assess the relation of vasectomy to the risk of these and other cancers. In the newly collected data, the multivariate relative risk estimate for prostatic cancer in vasectomized men was 1.2 (95% confidence interval (CI) 0.6-2.7). For lung cancer and testicular cancer, the relative risk estimates were 1.3 (95% CI 0.8-2.1) and 0.8 (95% CI 0.4-1.9), respectively; for lung cancer occurring > or = 15 years after vasectomy, the relative risk estimate was 1.9 but it was not statistically significant (95% CI 0.7-5.0). For pancreatic cancer, the relative risk estimate was 1.8 (95% CI 1.0-3.1). For each of the other cancers considered--malignant melanoma, large bowel cancer, bladder cancer, kidney cancer, lymphoma, leukemia, and other cancers--the relative risk estimate was 1.3 or less and compatible with a value of 1.0. The present data provide little support for an association of vasectomy with the risk of prostatic cancer or other cancers. In addition, the data from two sets of cases of prostatic cancer and controls interviewed consecutively illustrate that increased relative risks detected in screening for statistically significant associations may tend to have an upward bias and to be lower in subsequent data.

Adult↗
PubMed1994

Ovulation induction and risk of neural tube defects.

The relation between use of ovulation-inducing drugs and risk of neural tube defects (NTDs) was studied in a case-control surveillance programme. The frequency of any use of such drugs during the 6 months before the last menstrual period or during pregnancy was 3.0% for 1034 mothers of infants and fetuses with NTDs (cases) and 2.8% for 4081 mothers of those with other major congenital malformations (controls) (relative risk 1.1, 95% CI 0.8-1.7). Relative risks for clomiphene and for hormones were 0.8 (0.5-1.3) and 1.5 (0.7-3.4), respectively. These data suggest that use of ovulation-inducing drugs before conception does not increase the risk of NTDs.

Case-Control Studies↗
PubMed1994

Screening: assessment of current studies.

BACKGROUND: A major issue in decisions regarding screening women for breast cancer concerns ages of coverage, in particular, whether routine mass screening programs with mammography should cover women aged 40-49. Interpretation of results of studies on this question is affected by differences in design, adequacy of sample size, quality of mammography, period of follow-up, and other methodologic and content issues. METHODS: Experience in eight randomized controlled trials (RCTs) conducted over the past 30 years in the United States, Europe, and Canada were assessed, and problems influencing their conclusions were considered. RESULTS: The age groups studied in these RCTs varied, from 40-64 in the Health Insurance Plan (HIP) study to 40-74 in the Swedish two-country trials. In addition, they differed in periodicity and modalities of screening, with the HIP and the Canadian National Breast Screening Study providing annual examinations with mammography and clinical breast examination, and most of the other trials scheduling longer intervals between examinations with mammography alone. Great consistency is found, however, in the results for women aged 50-69, as all of these studies showed a reduction in breast cancer mortality in this age group, suggesting about a 30% decrease. For women aged 40-49, the studies showed no benefit 5-7 years after entry and an uncertain benefit 10-12 years after entry, and only one study offered information on long term effects. Additional follow-up is needed. Adequate data are not available for women 70 and older. CONCLUSION: Public health policy on mass screening with mammography for women aged 40-49 is questionable. At this time, the emphasis should be on physicians advising women about the uncertainty of the benefits of routine mammography when referrals are being considered.

Adult↗
PubMed1994

A case-control study of oral contraceptive use and invasive epithelial ovarian cancer.

The relation of oral contraceptive use to the risk of ovarian cancer was assessed with data collected during 1977-1991 from patients under 65 years of age in hospitals in Boston, New York, Philadelphia, and Baltimore. We compared 441 women with recently diagnosed invasive epithelial ovarian cancer to 2,065 control women. Logistic regression was used to control risk factors for ovarian cancer. The multivariate relative risk estimate decreased with the increasing duration of oral contraceptive use (p < 0.05): the estimate was close to 1.0 for duration categories of less than 3 years; it was reduced for the categories of 3-4 years of use and greater, but it did not decline further as the duration of use increased. For > or = 3 years of use, the estimate was 0.6 (95% confidence interval 0.4-0.8). The inverse association of risk with > or = 3 years of use was consistently present across categories of age, parity, interview year, and geographic area. It was apparent for as long as 15-19 years after cessation. Many different specific oral contraceptive formulations appeared related to a decreased risk; however, data were sparse for the newer types, particularly phasic preparations, and the ability to assess specific preparations in the context of use of multiple preparations was limited. The present data confirm previous reports of an inverse association of ovarian cancer risk with oral contraceptive use of several years in duration. They also suggest that the association may persist for as long as two decades and that it is not confined to any particular type of oral contraceptive formulation.

Adult↗
PubMed1994

Neonatal intensive care units: is the level of utilization still paralleled by infant mortality?

BACKGROUND: This research investigated the relationship of maternal place of residence with the utilization of neonatal intensive care units (NICU) and whether maternal residence was related to infant mortality in two contiguous Swiss cantons, Vaud and Valais, relying on the same tertiary NICU. Previous works have shown that infant mortality is close to the Swiss rate in Vaud, but elevated in Valais. METHODS: Analyses were based on linked birth and death certificates relating to the 57,962 single livebirths to mothers resident in Vaud or Valais delivered in hospitals over the 1979-1985 period. Data on utilization were retrospectively collected from NICU admissions' registers and linked to birth certificates. RESULTS: Results of logistic regression models pointed to a large difference for all birthweight groups, in NICU utilization between Vaud and Valais after adjustment for risk factors abstracted from the birth certificate, when tertiary NICU beds were considered. When the definition of NICU utilization was enlarged to all beds of an identified NICU, irrespective of the location of the unit and of the intensity of care provided to admitted newborns, there was a clear reduction in geographical variations. Neonatal and infant mortality were significantly higher in the lower NICU utilization region only among newborns weighing > or = 2500 g at birth. CONCLUSIONS: We found no difference in infant mortality (odds ratio 1.0) among < 2500 g newborns residing in regions characterized by a large difference in tertiary NICU utilization. Nevertheless, the limited sample size did not permit specific analyses of lower birthweight (e.g. < 1500 g) newborns. Replication of such research in other settings based on larger samples is needed.

Demography↗
PubMed1994

Does physician performance explain interspecialty differences in malpractice claim rates?

Physician specialty has been consistently associated with different malpractice claim rates, with neurosurgery, orthopedics, and obstetrics and gynecology having the highest rates. Whether these differences reflect physician performance or other aspects of patient care that are unique for each specialty is unclear. A retrospective cohort study was performed including 12,829 physicians involved in 8,221 closed cases from 1977 to 1991. For each case an assessment was made whether the plaintiff received an award and whether the physician care of the patient was indefensible. An award was made to the plaintiff in 42% of cases. Physician care was considered indefensible in 23% of the cases. The specialties with the highest award rates were anesthesiology (58.3%), obstetrics and gynecology (47.5%), and radiology (43.0%). Neurosurgery had the lowest rate of award (30.2%). The specialties with the highest indefensibility rates were radiology (36%), obstetrics and gynecology (27%), and anesthesiology (27%). Neurosurgery had the lowest indefensibility rate (10%). These results were unchanged after controlling for physician age, degree, site of training, certification status, and severity of patient injury. In conclusion, differences in award rate and indefensibility are present, but not large enough to explain the large variation in specialty claim rates. This suggests that the variation in malpractice rates results from factors other than a meaningful difference in physician performance.

Clinical Competence↗
PubMed1994

Erythrocytes from young but not elderly donors can bind and degrade immune complex- and antibody-bound C3 in vitro.

In situ aged erythrocytes (senescent erythrocytes from young donors and both young and old erythrocytes from elderly donors) demonstrate high levels of membrane-bound C3c and C3d and elevated susceptibility to in vitro phagocytosis. In this study we demonstrate that in situ aged erythrocytes are defective in their ability to degrade C3 fragments and clear them from the erythrocyte membrane. Erythrocytes from young donors bind complement-bearing immune complexes via CR1 and become susceptible to complement-mediated erythrophagocytosis ('innocent bystander' sequestration). Erythrocytes from elderly donors are defective in their ability to bind such immune complexes, as attested by the lack of an increment in membrane-associated C3 fragments as detected by flow cytometry and lack of an increment in in vitro sequestration. Factor I (serum)-dependent cleavage of C3 fragments and release of immune complexes from the erythrocytes of young donors lead to a drop in erythrocyte-associated C3 fragments and the disappearance of the 'innocent bystander' phenomenon. Inhibition of Factor I, and thus inhibition of C3b degradation and immune complex release for the erythrocyte membrane, enhances the levels of 'innocent bystander' sequestration of erythrocytes from young donors. Erythrocytes from elderly donors are defective in the dynamic process of CR1 binding of complement-bearing immune complexes and Factor I-associated release of membrane-associated C3 fragments. A defect in the ability of all in situ aged erythrocytes to clear their membranes of C3 fragments is also demonstrated for complement bound to the erythrocyte via IgM isoagglutinins. While erythrocytes from both young and elderly donors allow for the IgM-mediated binding of complement to the erythrocyte, only young erythrocytes from young donors demonstrate degradative activity with the release of membrane-associated C3c. Erythrocytes from elderly donors demonstrate lower levels of detectable CR1 (CD35), decay accelerating factor (DAF) (CD55) and Protectin (CD59) than do erythrocytes from young donors. Time course studies determine that the defect in handling of immune complexes observed for in situ aged erythrocytes is not due to differences in the kinetics of loading or releasing of immune complexes. These findings on the refractiveness of erythrocytes of elderly donors to uptake of immune complexes and the degradation of C3 fragments may be of importance not only in the understanding of erythrocyte sequestration, but also in the physiology of immune clearance in the elderly.

Adolescent↗
PubMed1994

The antimicrobial activity of essential oils and essential oil components towards oral bacteria.

A method for reproducibly determining minimal inhibitory concentrations and minimal bactericidal concentrations of plant extracts towards fastidiously and facultatively anaerobic oral bacteria, predicated upon measurements of optical densities in microtitre plate wells, was devised. The antimicrobial properties of some botanical oils were surveyed; of these, Australian tea tree oil, peppermint oil, and sage oil proved to be the most potent essential oils, whereas thymol and eugenol were potent essential oil components.

Actinomyces viscosus↗
PubMed1994

CD44 expression in Merkel cell carcinoma may correlate with risk of metastasis.

We retrospectively studied 25 cases of cutaneous primary, locally recurrent or metastatic Merkel cell carcinoma to see if expression of the cell surface marker CD44 correlated with metastatic potential. In 3 of 6 cases in which metastasis was documented, CD44 was found on membranes of tumor cells. Three cutaneous lesions associated with local metastasis did not express CD44. Three primary tumors expressed CD44 but had not disseminated at the time of this report; follow-up after excision of the primary lesion in these cases was less than 6 months. None of the primary or locally recurrent Merkel cell carcinomas followed longer than 6 months (14 of 19 cases) expressed CD44. We conclude that expression of CD44 in Merkel cell carcinoma may eventually be of some value in the assessment of prognosis of cutaneous Merkel cell carcinoma.

Aged↗