No abstract

No abstract

The present study was designed to investigate the effects of Zn administration on metallothionein concentrations in the liver, kidney, and intestine of copper-loaded rats. Male CD rats were fed a diet containing 12 mg Cu and 67 mg Zn/kg body wt. They were divided into either acute or chronic experimental protocols. Rats undergoing acute experiments received daily ip injections of either Cu (3 mg/kg body wt) or Zn (10 mg/kg body wt) for 3 d. Chronic experiments were carried out on rats receiving Cu ip injections on d 1, 2, 3, 10, 17, and 24, Cu injections plus a Zn-supplemented diet containing 5 g Zn/kg solid diet, or a Zn-supplemented diet alone. Rats injected Zn or Cu had increased MT concentrations in liver and kidney. Zn produced the most important effects and the liver was the most responsive organ. Rats fed a Zn-supplemented diet had significantly higher MT concentrations in liver and intestine with respect to controls. Increased MT synthesis in the liver may contribute to copper detoxification; the hypothesis of copper entrapment in enterocytes cannot be confirmed.

An association between the activity of the renin-angiotensin system and the development of spontaneous focal glomerular sclerosis (FGS) in rats has been observed: the onset is preceded by a decrease in plasma renin activity (PRA). This observation was facilitated by the use of Fawn-hooded rats, which develop spontaneous FGS at an early age. Male Fawn-hooded rats develop severe FGS as early as 3 months of age. Male Wistar rats do not develop similar lesions until after 1 year of age. Correspondingly the PRA drops much sooner in Fawn-hooded than in Wistar rats. The low PRA appears to be due to low plasma renin rather than a limitation of the renin substrate, angiotensinogen, which appears to be present in the Fawn-hooded plasma in nonlimiting quantities. In the FH male rats renin content of the kidney drops only after severe glomerular pathology is evident, implying that the low PRA may be due to a decrease in renin secretion by the chromaffin cells of the juxtaglomerular apparatus.

The long-term acceptance and success of the Barbie doll suggests the physical characteristics of the doll are perceived as attractive. When viewed in the context of universal attractiveness, response to the doll raises the question why Barbie is perceived as attractive. Published paleontological data on hominid fossils indicate how the shapes and anatomical proportions of humans have evolved. Included in the fossils are phenotypic traits no longer prevalent in humans (primitive) and phenotypic traits that have become increasingly prevalent (derived). It is noted that the anatomical proportions of the Barbie doll are exaggerated and emphasize derived characteristics. It was proposed that in the perception of human form, derived traits are perceived as attractive while primitive traits are perceived as unattractive. Drawings and photographs were utilized to survey reactions to a comparison of primitive vs derived traits by 495 subjects, instructed to select the shape or proportion they considered more attractive. There was significant agreement among the subjects that derived anatomical traits were perceived as more attractive than primitive ones. The Barbie doll is illustrative of how human beauty has evolved and indicates elements of human form that appear beautiful. The doll emphasizes our derived evolutionary traits and, possibly, that is why the doll is perceived as attractive.