Dimercaptopropane Sulfonate Chelation Affects In Vivo Hg and MeHg Distribution in Tissues and Urine of Prairie Voles (Microtus ochrogaster).

Methyl mercury cation (MeHg(+)) and divalent mercury (Hg(2+)) were quantified in urine, liver, kidney, and brain of prairie voles (Microtus ochrogaster) during a 12 week exposure to aqueous MeHg(+) at concentrations of 10, 100, and 1000 ng MeHg(+)/mL. Aqueous MeHg(+) exposures increased mercury accumulation in tissues of voles from each exposure group. Accumulation was greater within the higher two exposure groups. Similar [Hg(2+)] and [MeHg(+)] were determined within a given organ type before and after 2,3-dimercapto-1-propane sulfonate (DMPS) chelation. Similar correlations were seen for Hg(2+) and MeHg(+) concentrations in pre and post chelation urine. Post chelation urine more reliably predicted mercury species concentrations in tissues than did urine collected before chelation. These data demonstrate the utility of DMPS in noninvasive assessment of wildlife exposure to mercury, which may have utility in evaluating meta-population level exposure to hazardous wastes.

Mercury and methylmercury accumulation and excretion in prairie voles (Microtus ochrogaster) receiving chronic doses of methylmercury.

Methylmercury cation (MeHg) and divalent mercury (Hg++) accumulation in liver, kidney, and brain were quantified in prairie voles (Microtus ochrogaster) at 0, 3, 6, and 12 weeks during chronic exposure to aqueous MeHg. Dose groups received deionized water or aqueous solutions containing 9, 103, or 920 ng MeHg/ml. Our study presents temporal patterns of Hg++ and MeHg concentrations in organ tissues and makes inter-tissue comparisons at each time point to illustrate the accumulation and distribution of Hg species during the study. MeHg was accumulated in tissues for 3 weeks and then concentrations plateaued. Mercury accumulated in brain, liver, and kidney to average concentrations of 510 ng/g, 180 ng/g, and 3400 ng/g, respectively. MeHg and Hg++ concentrations were roughly equivalent in liver, kidney, and urine. MeHg concentrations in brain tissue were 2 to 20 times the concentrations of Hg++. Regression analysis was also used to demonstrate the utility of urinalysis as an indicator of Hg++ and MeHg concentrations in organ tissue (p < 0.001).

Testosterone and endurance exercise: development of the "exercise-hypogonadal male condition".

During the last 30 years a large number of research studies have been conducted examining reproductive endocrine dysfunction in exercising women. The number of similar studies examining men is still relatively small. Nevertheless, an increasing amount of research studies in men indicate endurance exercise training has significant effects upon the major male reproductive hormone, testosterone, and the hypothalamic-pituitary-testicular axis that regulates reproductive hormones. This review article addresses one reproductive endocrine dysfunction found in exercising men, what has been deemed the "exercise-hypogonadal male condition". Specifically, men with this condition exhibit basal (resting-state) free and total testosterone levels that are significantly and persistently reduced. The exact physiological mechanism inducing the reduction of testosterone is currently unclear, but is postulated to be a dysfunction (or perhaps a readjustment) within the hypothalamic-pituitary-testicular regulatory axis. The time course for the development of the "exercise-hypogonadal condition" or the threshold of exercise training necessary to induce the condition remains unresolved. The potential exists for these reduced testosterone levels within the exercise-hypogonadal male to disrupt and be detrimental to some anabolic or androgenic testosterone-dependent physiological processes. Unfortunately, extremely few research studies have addressed whether such processes are affected, and thus findings are inconclusive. Conversely, the alterations in testosterone levels brought about by endurance exercise training have the potential for cardiovascular protective effects and thus could be beneficial to the health of these men. Current evidence suggests this condition is limited to men who have been persistently involved in chronic endurance exercise training for extended periods of time (i.e., years). Many questions, however, regarding the male reproductive endocrine adaptive process to exercise and exercise training remain unanswered, necessitating the need for further research on this topic.

Acute porphyric disorders.

Acute porphyrias are classified into 3 distinct groups of rare genetic disorders of metabolic enzyme biosynthesis. Acute porphyrias can significantly impact multiple organ systems, which often provides a challenge to the dentist presented with such a patient. A case of hereditary coproporphyria is reported in a patient with many of the classical signs and symptoms. The patient also had complex dental needs that required special medical and pharmacotherapeutic modifications. The acute porphyrias are reviewed by the authors with presentation of this challenging case. Recommendations for other dental health care professionals encountering these patients are then presented.

A genomewide survey of basic helix-loop-helix factors in Drosophila.

The basic helix-loop-helix (bHLH) transcription factors play important roles in the specification of tissue type during the development of animals. We have used the information contained in the recently published genomic sequence of Drosophila melanogaster to identify 12 additional bHLH proteins. By sequence analysis we have assigned these proteins to families defined by Atonal, Hairy-Enhancer of Split, Hand, p48, Mesp, MYC/USF, and the bHLH-Per, Arnt, Sim (PAS) domain. In addition, one single protein represents a unique family of bHLH proteins. mRNA in situ analysis demonstrates that the genes encoding these proteins are expressed in several tissue types but are particularly concentrated in the developing nervous system and mesoderm.

YAC complementation shows a requirement for Wt1 in the development of epicardium, adrenal gland and throughout nephrogenesis.

The Wilms' Tumour gene WT1 has important functions during development. Knock-out mice were shown to have defects in the urogenital system and to die at embryonic day E13.5, probably due to heart failure. Using a lacZ reporter gene inserted into a YAC construct, we demonstrate that WT1 is expressed in the early proepicardium, the epicardium and the subepicardial mesenchymal cells (SEMC). Lack of WT1 leads to severe defects in the epicardial layer and a concomitant absence of SEMCs, which explains the pericardial bleeding and subsequent embryonic death observed in Wt1 null embryos. We further show that a human-derived WT1 YAC construct is able to completely rescue heart defects, but only partially rescues defects in the urogenital system. Analysis of the observed hypoplastic kidneys demonstrate a continuous requirement for WT1 during nephrogenesis, in particular, in the formation of mature glomeruli. Finally, we show that the development of adrenal glands is also severely affected in partially rescued embryos. These data demonstrate a variety of new functions for WT1 and suggest a general requirement for this protein in the formation of organs derived from the intermediate mesoderm.

YAC transgenic analysis reveals Wilms' tumour 1 gene activity in the proliferating coelomic epithelium, developing diaphragm and limb.

Wilms' Tumour 1 gene (WT1) is required for the correct development of the urogenital system. To examine its regulation and expression, we created several transgenic mouse lines containing a beta-galactosidase reporter driven by the human WT1 promoter. A 5 kb promoter weakly recapitulated a subset of the endogenous Wt1 expression pattern. In contrast, 470 and 280 kb YAC transgenes reproduced the correct pattern with high activity and highlighted new expression sites. Wt1 is expressed in the septum transversum revealing how its mutation causes diaphragmatic defects. Wt1 expression in the limb demarcates a zone between chondrogenic and apoptotic domains. Finally, Wt1 is expressed in mesenchymal cells derived from the coelomic epithelium. Based upon these and further data we discuss a Wt1 role in epithelial<-->mesenchymal transitions.

Rapid comprehensive two-dimensional separations of peptides via RPLC-optically gated capillary zone electrophoresis.

Coupled-column two dimensional (2D) separation systems offer potentially high peak capacity and are amenable to automation. Reversed phase liquid chromatography (RPLC) and capillary zone electrophoresis (CZE) are complementary techniques well suited for use in a 2D system. Optically gated CZE is a means of performing rapid CZE analyses. In a 2D system, these rapid CZE analyses enable more frequent sampling of the RPLC separation and thus more freedom in control of the RPLC analysis conditions. Complete 2D separations can be done in the time usually required to do the RPLC analysis alone. With the present system, a complete 2D analysis can be done in under 10 min. Because the peak capacity of a 2D method is inherently high, some of the available peak capacity can be exchanged for speed of analysis. Acceleration of the RPLC elution gradient will decrease analysis time, but RPLC resolution will suffer. However, because it is a 2D system, some of the resolution lost in the RPLC can be regained in the second dimension CZE analysis. Here, the RPLC gradient was done over only 2 min, but CZE analyses done every 2.5 s restore some of the resolution lost in the rapid RPLC gradient.

Comprehensive three-dimensional separation of peptides using size exclusion chromatography/reversed phase liquid chromatography/optically gated capillary zone electrophoresis.

Multidimensional separation methods are attractive because of their potentially high peak capacities. Coupled-column systems in particular offer the advantages of on-line detection and automation. With the development of rapid two-dimensional (2D) analysis, it becomes possible to consider three-dimensional (3D) separation systems. In such a 3D system, effluent from a slow first dimension is repetitively sampled into a rapid 2D system. In the resultant data, each sample component has been subjected to three separative displacements, and the overall peak capacity is the product of that of each of the three dimensions. This paper demonstrates a comprehensive coupled-column 3D analysis of peptides. Size exclusion chromatography (SEC) is used as the first dimension to separate sample components by molecular weight, over an analysis time of several hours. The SEC effluent is repetitively sampled on-line into a rapid 2D reversed phase liquid chromatography/capillary zone electrophoresis (CZE) system with an analysis time of 7 min. Detection of sample zones is done only after the final CZE separation, by laser-induced fluorescence detection. Analysis data from this system consist of a series of 2D "slices" of the SEC effluent, which when stacked together give the 3D separation "volume".

Resolution of cis and trans isomers of peptides containing proline using capillary zone electrophoresis.

Capillary zone electrophoresis (CZE) is known for its high separation efficiency. Optically gated CZE is a form of CZE that allows rapid analyses while high separation efficiency is maintained. Analysis of peptides containing proline with CZE and optically gated CZE gives two peaks for dipeptides and multiple peaks for oligopeptides containing more than one proline. The multiple peaks are believed to be due to the cis and trans forms possible in peptide bonds containing proline. Isomerization between the cis and trans forms takes place at room temperature with a lifetime of seconds to minutes. Resolution of these peaks in CZE is found to be a function of separation efficiency and time of analysis. Rapid analyses with relatively lower separation efficiency give resolution equal to or better than that of longer analyses with much higher efficiency. This confirms the relationship between the multiple peaks and isomerization between the cis and trans forms. To extract kinetic information from the experimental data, a digital simulation is used to model the separation obtained experimentally. The equilibrium constant and rate constants that give the best fit of the simulated data to the experimental data are considered estimates of the actual values for the given experimental conditions.

Study of zone broadening in optically gated high-speed capillary electrophoresis.

Fluorescein isothiocyanate (FITC) labeled compounds are separated by capillary zone electrophoresis (CZE) in seconds rather than minutes while high separation efficiency is maintained. These rapid analysis times are achieved through high electric fields applied over short separation distances and the use of a unique optical-gating injection system. The optical-gating injection is based on photodecomposition of FITC induced by an argon ion laser beam. A fraction of this same laser beam is also used for detection of the analyte zones by on-column laser-induced fluorescence. Four FITC-labeled amino acids and fluorescein dye were analyzed to compare system performance to that predicted by theory. To do so, the total variance for each analyte zone was measured experimentally. This was compared to the sum of the theoretically expected variance contributions from the injection and detection systems and longitudinal diffusion. The variance due to longitudinal diffusion was calculated from diffusion constants measured experimentally with a traditional CZE system. After accounting for these three known sources of variance, this method is found to achieve better than 80% of the performance predicted by theory in analysis times as short as 2-3 s.

Two-dimensional separations of peptides and proteins by comprehensive liquid chromatography-capillary electrophoresis.

Analysis of biological samples is problematic because of their complex composition. Reversed phase liquid chromatography (RPLC), size exclusion chromatography (SEC), and, more recently, capillary zone electrophoresis (CZE) are routinely used for the analysis of these samples, but are eventually limited because they are one-dimensional (1-D) methods. As sample complexity increases, the separation efficiency necessary to resolve a large number of sample components in one dimension becomes prohibitively high. A solution to this problem has been to use a two-dimensional (2-D) approach. Each dimension in a 2-D separation relies on a different separating mechanism. By expanding the separation into two dimensions, sample components unresolved in the first dimension can often be separated in the second. This circumvents the requirement for extremely high efficiencies in either dimension. Two-dimensional slab gel electrophoresis has been used successfully in this area, but a more instrumental approach is desired. In this paper we describe three coupled-column approaches to 2-D separations. First, microcolumn SEC-CZE is explored as a means of 2-D protein analysis. Next, RPLC-CZE is investigated for analysis of peptides in tryptic maps. Finally, RPLC is coupled with fast CZE (FCZE), a unique form of CZE analysis, for fast 2-D analysis of peptides. Details of the instrumentation used in these 2-D systems will be presented along with the results of some typical 2-D analyses.

Characteristics of peak aerobic capacity in symptomatic and asymptomatic subjects with left ventricular dysfunction. The Studies of Left Ventricular Dysfunction (SOLVD) Investigators.

Expired gas analysis was used to determine the aerobic exercise performance of subjects with depressed left ventricular (LV) systolic function and congestive heart failure (CHF). To determine whether subjects with no or minimal CHF have better aerobic exercise performance than do those with overt CHF, oxygen consumption (VO2) at anaerobic threshold (AT) and peak exercise was measured in 184 subjects with LV ejection fraction less than or equal to 0.35 who participated in the Studies of Left Ventricular Dysfunction. Subjects were divided into those with overt CHF needing treatment (treatment trial; n = 20) and those who had neither overt CHF nor treatment for CHF (prevention trial; n = 164). Treatment trial subjects had a lower LV ejection fraction (0.25 +/- 0.07) than did prevention trial ones (0.29 +/- 0.05; p = 0.001), but there were no differences in age, gender, body weight, resting heart rate and blood pressure. Treadmill exercise testing was performed after 2 to 3 weeks of placebo (no angiotensin-converting enzyme inhibitor) treatment. Treatment trial subjects exercised for a shorter time (493 +/- 160 seconds) and attained a lower peak VO2 (13 +/- 4 ml/kg/min) and VO2 at AT (11 +/- 4 ml/kg/min) than did prevention trial ones (842 +/- 277 seconds, and 20 +/- 6 and 16 +/- 5 ml/kg/min, respectively). Analysis of covariance showed that the differences in peak VO2 and VO2 at AT were statistically significant between the 2 trials after adjusting for age, gender, LV ejection fraction and New York Heart Association functional class.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of small amounts of organic solvents in aqueous samples on argon inductively coupled plasma spectrometry.

The presence of organic solvents in aqueous samples in concentrations as low as 0.1% by volume had a large effect on emission and fluorescence signals. Both atom and ion emission signals were depressed when organic solvents were present. In contrast, Sr II fluorescence intensities were enhanced by up to a factor of 3.5 when the sample contained 2% (v/v) organic solvent. More ions were produced when the sample contained organic solvent. However, the fractions of atoms and ions that were excited and emitted light decreased. Ar and H emission intensities can be used as diagnostic signals to warn the operator when plasma conditions have changed due to the presence of organic solvents.

Melanosis of the gall bladder.

A case of melanosis of the gall bladder is described. Ultrastructural examination confirms that the pigment is related to lipofuscin.

Proximal tubular adenoma of the kidney.

A case of proximal tubular adenoma of the kidney (renal "oncocytoma"), confirmed by electron microscopy, is reported. This benign tumour has been mistaken for renal adenocarcinoma in the past by both surgeons and pathologists.

Perceptions of dentofacial morphology by laypersons, general dentists, and orthodontists.

Line drawings of facial profiles and color photographs of dentitions were evaluated subjectively by 1,150 parents, 72 general practictioners of dentistry, and 54 orthodontists with regard to the normality and abnormality in dentofacial morphology and the need for orthodontic treatment. A significant difference was found between the evaluations of the parents and the professional groups in ten of the 11 facial profiles and in seven of the 11 photographs of dentitions. In general, the parents considered more of the examples acceptable and not requiring orthodontic treatment than did the professional groups. The dentists and orthodontists deviated significantly in their ratings onjy in their judgement of "ugly duckling" example (picture 22, higher abnormal rating by the dentists) and the profile example 10 (higher abnormal rating by orthodontists). number of orthondontists may have associated the conditions in picture 10 with a Class II, Division 2 malocclusion and, as such, scored it abnormal.

Intraabdominal desmoid causing death in a young man with Gardner's syndrome.

The case is reported of a 22-year-old man with Gardner's syndrome who died as a consequence of unremitting spread of an intraabdominal desmoid four and a half years after colectomy for polyposis, and two and a half years after clinical presentation of the desmoid tumour.