Localized hypoxia may have caused coral reef mortality at the Flower Garden Banks

Coral Reefs - On July 25, 2016, turbid water and dead corals, sponges and other invertebrates were discovered at the East Bank (EB) of the Flower Garden Banks (FGB) National Marine Sanctuary....     

Validity of hair mineral testing

The variance of testing was compared between the College of American Pathologists clinical survey and that of a recent review about hair mineral testing. The review suggested that the accuracy of hair mineral testing was unreliable. In general, there was a greater range of variance in the College of American Pathologists testing results. These latter results are based on laboratory testing and are used as a “yardstick” to determine if a laboratory passes or fails that analyte and are considered a “gold standard.” An extract, which resulted from a method that avoided the washing step, was compared among five laboratories. Very good precision resulted, indicating that the varied washing steps used by the laboratories in a recent review were probably the source of much variance. Analysis of hair analysis seemed to yield important information in several historical or forensic cases involving Ludwig von Beethoven, Napoleon Bonaparte, ex-US-presidents Zachary Taylor and Andrew Jackson, and Charles Hall, an Arctic explorer. Several elements that were reviewed, including arsenic, cadmium, cobalt, germanium, lead, lithium, manganese, mercury, nickel, and thallium, showed relationships between body burden, dosage, and exposure or toxicity. Evidence of toxicity could not be found by measuring hair aluminum or vanadium. Chromium, selenium, and zinc seemed to have nutritional value. Ratios of hair elements with clinical importance could not be found.     

Evidence for the antimutagenicity and the mutagenicity of selenium

Evidence is summarized for the antimutagenicity as well as the mutagenicity of selenium. In general, antimutagenicity predominates at physiological levels, while mutagenicity occurs at 3 to 1000 times normal physiological levels.     

Lysosomal enzyme changes in growing and regressing mammary tumours

Rat mammary tumours induced by 7,12-dimethylbenz[a]anthracene can undergo repeated growth and regression during successive pregnancies. In a 10-day period after birth about half of the tumours regressed 50% or more. The concentrations of the lysosomal enzymes increased in regressing mammary tumours to the following multiples of the initial values: β-glucuronidase, 7·7; β-galactosidase, 3·9; cathepsin, 2·9; acid ribonuclease, 2·1; arylsulphatase A, 1·5; acid phosphatase, 1·4. In contrast, several non-lysosomal enzymes failed to increase. Activities in the post-partum uterus increased to the following multiples of the initial values: β-glucuronidase, 5·8; cathepsin, 5·5; acid ribonuclease, 4·3; β-galactosidase, 2·2; acid phosphatase, 1·8. Arylsulphatase A in the post-partum uterus decreased significantly, suggesting a non-lysosomal distribution or a special function related to pregnancy. No other significant changes were observed in the lysosomal or non-lysosomal enzymes in the hormone-independent liver or hormone-dependent normal mammary gland. The ratio of free to bound arylsulphatase A and acid ribonuclease decreased slightly 1–3 days after birth because of problems in homogenizing the tumours. At days 4–8, however, there was a dramatic increase in the ratio of the free to bound activities. The results can be explained in terms of the lysosomal theory of intracellular digestion.     

Calcium,magnesium, and other elements in the red blood cells and hair of normals and patients with premenstrual syndrome

This study compared the levels of 18 red cell elements and 22 hair elements in 46 patients (median age: 36.2 yr) diagnosed with PMS (premenstrual syndrome) to 50 normals (median age: 37.7 yr). Significantly lower amounts of calcium, chromium, copper, and manganese were found in the blood of patients with PMS. The ratios of Mg/Ca and K/Na and toxic metals such as lead, arsenic, and germanium were significantly elevated in the PMS patients. In hair, mercury and the Zn/Cu ratio were significantly greater in the PMS patients than the controls, but iron, potassium, and the Mg/Ca ratio were lower. The highly significant Mg/Ca ratio in blood cells may be indicative of a more complex relationship between PMS and magnesium and calcium than either element alone. The significantly lower blood cell calcium level found in these studies may provide additional evidence that PMS may be related to a calcium-deficiency state or a metabolic defect involving calcium.     

Antioxidants reduce the mutagenic effect of malonaldehyde and beta-propiolactone. Part IX. Antioxidants and cancer.

Increasing concentrations of malonaldehyde and beta-propiolactone were increasingly mutagenic with 7 mutants of Salmonella typhimurium, 5 of which mutated bya frameshift mechanism and 2 of which mutated through base-pair substitution. The antioxidants vitamin C, vitamin E, selenium and butylated hydroxytoluene (BHT) at 3 logarithmic concentrations markedly reduced mutagenesis in those strains which mutated by frameshift mechanism.     

Genetic toxicology of ascorbic acid

The activation mechanism of emodin, a fungal anthraquinone and constituent of rhubarb, into a direct mutagen to Salmonella typhimurium TA1537 was investigated by using the S9 and microsomes of rat livers. Upon incubating emodin with the hepatic S9 derived from PCB-pretreated rats, this anthraquinone exhibited mutagenicity in the presence of NADPH or NADH, and this enzymatic activation, maximal at pH 7.0 and occurring in the microsomes, was induced by the pretreatment of rats with PCB, 3-methylcholanthrene or phenobarbital and was inhibited by α-naphthoflavone, SKF 525A and carbon monoxide. Thin-layer chromatographic analysis revealed that emodin was biotransformed by the microsomal enzymes into at least 5 quinonoid metabolites, among which one pigment, identified as 2-hydroxyemodin (1,2,3,8-tetrahydroxy-6-methyl-anthraquinone), was proved to be a direct mutagen to the test strain, and the remaining 4 quinonoid metabolites were negative or far less active than this active principle.     

Selenium metabolism and function

Selenium like many other elements has a bimodal effect. At lower concentrations selenium is an essential trace element necessary for the growth of man and animals. However, at higher concentrations, selenium has toxic properties for man and animals. The biochemistry of selenium as a component of glutathione peroxidase and the analytical properties of selenium are also outlined.     

The genotoxicity of selenium

Selenium at nutritional levels has been shown to have numerous anticarcinogenic or preventative effects against carcinogen-induced breast, colon, liver and skin cancer in animals. Many of these anticarcinogenic effects have been summarized. In addition, numerous mutagenic and antimutagenic effects of selenium compounds have been reported. Some of the selenium compounds frequently tested for mutagenicity are listed in Table 1. Because of the numerous reported anticarcinogenic and preventative effects of selenium, many individuals are supplementing their diets with amounts of selenium that are greater than the recommended daily requirement. Selenium is also used widely in industrial products such as selenium rectifiers, photoelectric batteries, alloys and paints. Because selenium at higher levels is known to be toxic, there should be a greater understanding about its genotoxic as well as its beneficial effect. The object of this review is to summarize experimental evidence both for the antimutagenic and the mutagenic effect of selenium.