Comparisons of three practical field devices used to measure personal light exposures and activity levels.

This paper documents the spectral and spatial performance characteristics of two new versions of the Daysimeter, devices developed and calibrated by the Lighting Research Center to measure and record personal circadian light exposure and activity levels, and compares them to those of the Actiwatch Spectrum (Philips Healthcare). Photometric errors from the Daysimeters and the Actiwatch Spectrum were also determined for various types of light sources. The Daysimeters had better photometric performance than the Actiwatch Spectrum. To assess differences associated with measuring light and activity levels at different locations on the body, older adults wore four Daysimeters and an Actiwatch Spectrum for five consecutive days. Wearing the Daysimeter or Actiwatch Spectrum on the wrist compromises accurate light measurements relative to locating a calibrated photosensor at the plane of the cornea.

Historical dimensions of population structure in a continuously distributed marine species: The case of the endemic Chilean dolphin.

The complementarity of historical and contemporary processes contributes to understanding the genetic structure of continuously distributed marine species with high dispersal capabilities. Cephalorhynchus eutropia, has a continuous coastal distribution with strong genetic differentiation identified by nuclear DNA markers. We explored the historical dimension of this genetic differentiation between northern and southern populations to evaluate phylogeographic structure. Additionally, we conducted mtDNA and microsatellite analyses to detect past and recent demographic changes. The southern population was characterized by lower genetic diversity with a signal of population expansion, likely associated with ice retreat and habitat extension after the Last Glacial Maximum (LGM). In contrast, structure within the northern population was more consistent with stable historical population size. Approximate Bayesian Computation analyses suggested that during the LGM, C. eutropia persisted in the northern area; while the south was colonized by dispersal ~11,000 years ago followed by population expansion. This study shows that Chilean dolphin population structure is consistent with predictions from the Expansion-Contraction biogeographic model, with a poleward post-glacial shift revealed in current genetic structure. The results also confirm the validity of the population units previously identified, demonstrating their historical origin and highlighting the utility of integrating genetic markers with different temporal scale resolutions.

Mitomycin-associated renal failure. Case report and review.

Renal failure due to mitomycin chemotherapy is a poorly appreciated entity often associated with microangiopathic hemolytic anemia. We describe a 45-year-old man in whom renal failure and anemia developed, without evidence of hemolysis, five months after beginning chemotherapy with mitomycin, fluorouracil, and doxorubicin hydrochloride. A biopsy specimen taken from the patient's kidney showed fibrin thrombi in two of 18 glomeruli and in several small arteries. The patient's condition required institution of maintenance dialysis. Similar reports from the literature are reviewed.

Transgenic systems for in vivo mutation analysis.

Transgenic mice carrying shuttle vectors containing the lacI gene as the target permit the in vivo measurement of mutations in multiple tissues and have been used to test the mutagenic effects of several compounds. Tissue-specific and time-dependent responses have been observed, and the spectrum of mutations determined by sequencing allows analysis of the role of expression time in mutagenesis. The results obtained from sequencing analysis have demonstrated spectra paralleling those observed in alternative in vivo assays. In addition to color screening, modifications to this system have permitted direct selection for mutations in the lacI target by a variety of methods. Transgenic rats containing the same lambda/lacI shuttle vector have been developed for inter-species comparison of mutagenesis testing results, which may offer a better understanding of the specific mechanisms involved in mutagenesis at the molecular level in vivo.

Determination of boron in silicon-bearing alloys, steel, and other alloys by pyrohydrolysis and inductively-coupled argon-plasma spectroscopy.

Boron is quantitatively separated from silicon-bearing and other inorganic materials by pyrohydrolysis. Microgram amounts of boron are separated by passing oxygen-saturated steam over a sample mixed with vanadium oxide and copper oxide. The distillate is collected in dilute potassium hydroxide solution and determined by inductively-coupled argon-plasma spectroscopy.

Coccidioidal meningitis diagnosed by skin biopsy.

We present a patient with coccidioidal meningitis whose diagnosis was not confirmed until a skin biopsy was performed. Because he lived in an area where coccidioidomycosis is not endemic, his meningitis was at first attributed to tuberculosis or sarcoidosis. After a verrucous lesion from the face was biopsied and the diagnosis substantiated, the patient responded well to consolidation therapy consisting of intrathecal amphotericin B and oral ketoconazole.

Survey of smoking knowledge, attitudes and practice in school children in Honduras.

OBJECTIVE: The aim of this study was to survey Honduran pre-adolescent knowledge, perceptions and experience regarding smoking. METHODS: A 12-item survey was administered in the classroom to fifth and sixth grade students. The main outcome measures were a description of demographic factors, personal smoking experience, knowledge of health risks, attitudes about tobacco use and perceived sources of information. RESULTS: A total of 225 students were surveyed. The majority were aware that smoking is bad for health, and most reported never having smoked. Most viewed smoking as ugly. Friends and family were selected as the major source of information. CONCLUSIONS: School children in this area of Honduras are aware of the health risks of smoking and view smoking as unattractive.

Hyperthyroidism in end-stage renal disease.

We report the 2nd patient to have hyperthyroidism while on maintenance hemodialysis. This case is instructive because the diagnosis of hyperthyroidism in uremic patients is difficult due to similar signs and symptoms. This case report describes, for the first time, the unique interaction between hemodialysis and thyrotoxic heart disease. Paroxysmal atrial fibrillation and severe hypotension interfered with all hemodialyses. Only the correction of the hyperthyroid state and withdrawal of all beta-blocking agents allowed resumption of normal hemodialysis. The delayed gastric emptying and hypercalcemia ultimately resolved with return to the euthyroid state and did not recur during 10 months of follow-up.

Serum potassium concentrations in cyclosporine- and azathioprine-treated renal transplant patients.

Hyperkalemia was commonly observed in successful renal transplant patients treated with cyclosporine and prednisone. At 1, 3 and 6 months after transplantation, 13 of 50, 9 of 50, and 5 of 50 patients, respectively, had serum concentrations of potassium greater than 5 mEq/1. This contrasts with the finding of hyperkalemia in only 1 of 13 comparable patients treated with azathioprine and prednisone. Mean serum concentrations of potassium at these dates were significantly higher in cyclosporine-treated patients than azathioprine-treated patients. The 2 patient groups had similar mean serum concentrations of chloride, bicarbonate and creatinine, and mean creatinine clearances at 1 and 3 months. Exposure to diuretic agents and antihypertensive agents was similar in the 2 groups. Serum concentrations of electrolytes and renal function data in hyperkalemic and normokalemic transplant patients receiving cyclosporine were similar. These observations suggest an association between cyclosporine administration and hyperkalemia in renal transplant recipients.

Induction of hepatic mutations in lacI transgenic mice.

Transgenic B6C3F1 and C57BL/6 mice containing a lambda shuttle vector that carries a lacI target and an alpha lacZ reporter gene have been constructed for use in in vivo mutagenesis assays. After chemical treatment of mice carrying the lacI target gene, genomic DNA is isolated and the shuttle vector is recovered by exposing the DNA to lambda phage packaging extracts in vitro. Mutations in the lacI target gene that inactivate the repressor gene allow expression of the alpha lacZ reporter gene, resulting in blue mutant plaques. We have examined the ability of two genotoxic agents, dimethylnitrosamine (DMN) and methylmethane sulfonate (MMS), to induce mutations in these transgenic mice. Both compounds induce a variety of DNA adducts in mouse liver; DMN is a hepatocarcinogen that induces significant hepatic cell proliferation, but MMS is not hepatocarcinogenic and does not induce hepatic cell proliferation. The effects of animal age, differences in strain and dosing regimen, and length of expression time were evaluated. Mice were treated for 5, 14 or 21 days and were sacrificed 1, 8 or 22 days after the final dose to evaluate the effects of increased expression time on mutant frequency in liver. In 3 week old mice, DMN (2 mg/kg/day) produced 10- to 20-fold elevations in mutant frequency that increased with expression time and the number of treatments. In contrast, MMS (20 mg/kg/day) failed to increase the mutant frequency. DMN failed to induce mutations in 6 week old mice at 2 mg/kg/day, but 4 mg/kg/day yielded significant elevations in hepatic mutations. Sequencing results indicate that treatment of mice with DMN produced predominantly C:G-->T:A transitions.(ABSTRACT TRUNCATED AT 250 WORDS)