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Biomedical subjects

P Weis

Publications and source records attributed to P Weis.

58 records · Page 4Linked to original sources
PubMedDate not supplied

Hepatic histopathology in two populations of the mummichog, Fundulus heteroclitus.

The pollution-tolerant mummichog, Fundulus heteroclitus, inhabits a heavily contaminated estuary, Piles Creek (PC), in Linden, NJ. PC contaminants include PAHs, PCBs and many metals, including high Hg and Pb. PC mummichog livers and kidneys were compared with those from a pristine estuary in Tuckerton (TK), NJ, by standard histopathological methods, with quantification by computerized image analysis. PC livers had > 2 x the lipid ratios of TK livers. Cell sizes and shapes were not different between populations. TK livers had a 25% incidence of basophilic areas and an age-related 30% incidence of macrophage aggregates; PC livers had none of these lesions. PC livers had a 100% incidence of necrotic foci, compared with 55% of TK livers. Inflammation was noted in 50% of TK livers but only 27% of PC livers. Curiously, the TK livers had a 45% incidence of metacercarial cysts of a digenetic trematode, while none were found in the PC livers. The TK focal necrosis and macrophage aggregates coincided with parasite infestation. There were no observed kidney lesions in either population. Positive biomarkers in this species thus included high hepatic lipid content, possibly necrosis, but no other lesions. The lack of trematode cysts in PC livers may reflect the lack of an intermediate host in this low biodiversity estuary.

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PubMedDate not supplied

Development of thyroid abnormalities in mummichogs, Fundulus heteroclitus, from a polluted site.

Previous studies showed that adult and 6-month-old young-of-year Fundulus heteroclitus from a polluted site have enlarged thyroid follicles and (in adults) higher thyroxine levels compared to fish from an unpolluted reference site. This study's purpose was to discover when in development these differences begin to appear. For 15-20 mm fish, the average follicle size of the polluted population was significantly larger than that of the reference population, similar to the pattern found in older fish. However, for the smaller size (12-14.5 mm), the average follicle size of fish from the polluted site was significantly smaller. Although not statistically significant, radioimmunoassay measurements of thyroxine levels were consistent with follicle differences: in larger sizes (20-25 and 15-20 mm) fish from the polluted site had higher thyroxine levels but the smaller size (12-14.5 mm) had lower levels. Therefore, the thyroid abnormalities seen in adults begin when the fish are approximately 15-20 mm long. However, the follicle size reversal for the 12-14.5 mm range may also indicate abnormality at that developmental stage.

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PubMedDate not supplied

The contraceptive potential of breastfeeding in Bangladesh.

A consensus statement issued by the World Health Organization and the United Nations Children's Fund at the Bellagio conference in 1988 recommended that women begin practicing contraception six months after childbirth or when their menstrual cycle resumes, whichever occurs first. The question to be resolved is whether this approach, known as the Bellagio mixed-t strategy, should be adjusted to local patterns of lactational amenorrhea. Data from interviews with 4,580 Bangladeshi women with a currently open birth interval were analyzed with respect to the women's current status of breastfeeding, amenorrhea, contraception, and pregnancy. Pregnancies among breastfeeding, amenorrheic women occurred only beyond 12 months postpartum, while some menstruating women were observed to be pregnant from three months postpartum onward. The results of this study give evidence that the Bellagio recommendation can be best applied with country-specific adjustments. Bangladesh, for example, could safely adopt a strategy with a 12-months' cutoff point.

Adolescent↗