Monochromatism determined at a long-wavelength/middle-wavelength cone-antagonistic locus.

The foveal increment threshold spectral sensitivity function for a 500 msec raised cosine stimulus without spatial edges exhibits a sharp drop or "notch" in sensitivity that coincides with the wavelength of a long-wavelength adapting field. An appropriate name for this phenomenon is the "Sloan notch", after Louise Sloan, who first observed a notch in a foveal threshold spectrum. We have examined suprathreshold discriminability on both sides of the Sloan notch produced by a 6700 td, 578 nm adapting field. In a temporal two-alternative forced-choice paradigm, a suprathreshold 650 nm low-frequency "standard" stimulus was paired with low-frequency "test" stimuli, of wavelength between 600 and 670 nm and varied intensity; the observer's task was to identify the interval containing the standard. Discriminability of the test and standard typically dropped to chance for some particular test intensity, producing "indiscriminability action spectra", up to 0.7 log units above threshold. Truncated spectra (between about 530 and 560 nm) were also obtained from observers on the middle wavelength side of the Sloan notch, for a 550 nm standard. The indiscriminability action spectra of each observer were identical, up to scaling, with the observer's threshold action spectrum. Analysis of the action spectra shows that the indiscriminable stimuli are rendered equivalent at the input to a neural pathway where L- and M-cone signals converge with opposite sign. We also investigated discriminability in the spectral region containing and immediately surrounding the Sloan notch. Suprathreshold stimuli in the spectral region near the notch produce percepts that are always discriminable from 650 and 550 nm standards (and from one another), and thus we conclude that in this spectral region, perception is mediated in part by a pathway distinct from that which signals the standards. The action spectrum of this latter pathway was estimated with a variant of the discrimination procedure, and found similar to V lambda over the spectral region 575-610 nm.     

Development of a computerized pharmacy therapeutic recommendation tracking program

Several important lessons were learned during this pilot project. First, the timely feedback of results, in the form of a concise report, to the pharmacists documenting the recommendations was very useful and aided in their future participation in the program. Second, the design of the database that restricted the data entry person to choose from a list of scrollable choices enhanced the utility of the database for reporting purposes. Future work is needed to facilitate data entry by the pharmacist recording the recommendation.     

Immunohistologic and ultrastructural comparison of the dermal papilla and hair follicle bulb from "active" and "normal" areas of alopecia areata.

The "active" edges of patches of alopecia areata and normal areas from the same scalp (i.e., bearing normal terminal hair) from seven patients with alopecia areata were investigated immunohistologically. Similar areas from a further eight patients were examined using light and electronmicroscopy. "Active" and "normal" areas of alopecia areata scalps were immunohistologically similar and varied from normal controls in the number, distribution, and ratio for T4 and T8-positive cells. Similarly the ultrastructural changes seen in the "active" areas when compared to normal controls were also present in the "normal" areas of alopecia areata scalps. The most significant differences found between normal "control" follicles and both "active" and "normal" areas of alopecia areata scalps were the polymorphic nature of the dermal papilla cells and the loss of cellular organization within the dermal papillae taken from alopecia areata scalps. In addition, the junction between the dermal papilla and the bulb of the hair follicle, the dermo-epithelial junction of the hair follicle bulb, demonstrated critical changes in follicles taken from both "active" and "normal" areas of alopecia areata scalps. These results support the suggestion of a subclinical state of alopecia areata and indicate that further work on the etiology of alopecia areata should be directed towards the "normal" areas of alopecia areata scalps, in particular the cells of the dermal papilla and the dermo-epithelial junction of the hair follicle bulb.     

Body burden of polychlorinated biphenyls among persons employed in capacitor manufacturing

Summary In an effort to assess exposure among workers engaged in capitor manufacture, PCB concentration was determined in plasma (290) and adipose tissue (61). In general, males had higher concentrations of PCBs than females.The correlation of plasma concentration (1–546 ppb) of the more highly chlorinated PCBs, which had been used in the past, with total duration of employment suggested accumulation over time. The gc-ec pattern of these PCB peaks was, in most cases, characteristic of exposure to a PCB mixture with 54% chlorine.The less highly chlorinated PCBs, di-, tri-, and tetrachlorobiphenyls, were the source of current exposure, and were observed in concentrations of 6–2530 ppb in plasma. Higher exposure occurred among persons with direct contact with PCBs, in jobs such as capacitor filling.Adipose tissue concentrations, for both the more highly chlorinated PCBs (1–165 ppm) and lower chlorinated PCBs (0.6-414 ppm), were proportional to those in plasma.Abbreviations PCB polychlorinated biphenyl - p,p-DDE 2,2-bis-(4-chlorophenyl)-1,1-dich-loroethylene - DDT dichlorodiphenyltrichloroethane Presented in part, at the XIX. International Congress on Occupational Health, Dubrovnik, September, 1978     

Comparing supervisors' self-evaluations to their administrators' evaluations

Research findings show that administrators generally tend to rate their supervisors lower than supervisors rate themselves. This second in a series of three articles pinpoints several problems areas in supervisor performance. Suggestions for improvement are given.     

Hydrolysis kinetics of propylene glycol monomethyl ether acetate in rats in vivo and in rat and human tissues in vitro.

The kinetic equivalency of propylene glycol monomethyl ether (PGME), derived from propylene glycol monomethyl ether acetate (PGMEA), as well as the parent compound (PGME) following intravenous administration to Fischer 344 rats was evaluated. In addition, in vitro hydrolysis rates of PGMEA in blood and liver tissue from rats and humans were determined. The blood kinetics were determined following iv administration to rats of PGME and PGMEA of low [10 and 14.7 mg/kg body weight (bw)] or high (100 and 147 mg/kg) equimolar dosages of PGME and PGMEA, respectively. The blood time courses of PGME elimination for both dosages of both compounds were identical. Half-lives of PGMEA elimination following iv administration of 14.7 or 147 mg PGMEA/kg bw were calculated to be 1.6 and 2.3 min, respectively. Rat and human in vitro hydrolysis rates of PGMEA were determined by incubation of 5 or 50 microg PGMEA/ml in whole blood or liver homogenate. The rate of loss of PGMEA was more rapid in rat blood than in human blood, with hydrolysis half-lives of 36 and 34 min in human blood and 16 and 15 min in rat blood for the 5 and 50 microg/ml concentrations of PGMEA, respectively. In contrast the rate of loss of PGMEA in human and rat liver homogenate incubations was similar, 27-30 min and 34 min, respectively. These data demonstrate the rapid hydrolysis of PGMEA in vivo to its parent glycol ether, PGME and that, once hydrolyzed, the kinetics for PGME derived from PGMEA are identical to that for PGME. This study supports the use of the toxicological database on PGME as a surrogate for PGMEA.     

AUTOPSY FINDINGS IN THE WOLCOTT-RALLISON SYNDROME

Wolcott-Rallison syndrome is a rare autosomal recessive condition characterized by diabetes mellitus arising in early infancy and multiple epiphyseal dysplasia. To date, nine cases have been described in the world literature. We report an affected girl who died at the age of 4 years and on whom a full autopsy was performed. In addition to neonatal diabetes mellitus and epiphyseal dysplasia, this child had mental retardation and recurrent episodes of self-limiting hepatic failure. Autopsy revealed severe pancreatic hypoplasia and markedly abnormal pancreatic histology, while histology of the bone was consistent with epiphyseal dysplasia. There was laryngeal stenosis and pulmonary hypoplasia. The heart was enlarged with mitral valve dysplasia and stenosis, left atrial dilatation, left ventricular hypertrophy, and endocardial fibroelastosis. Examination of the central nervous system showed arrhinencephaly and cerebellar cortical dysplasia. The liver showed minor histological abnormalities but no features were present to account for the recurrent hepatic failure. In addition to Wolcott-Rallison syndrome this child had a deletion at 15q11-12 in 65 of her cells.     

Merosin-deficient congenital muscular dystrophy and cortical dysplasia.

Congenital muscular dystrophy (CMD) encompasses a heterogenous group of muscle disorders with autosomal recessive inheritance, characterized by muscular weakness and hypotonia at birth or within the first few months of life and developmental delay. Merosin-deficient CMD is a clinically distinct form which may be associated with significant abnormalities of the brain detectable by neuroimaging. We report two siblings of consanguineous parents with merosin-deficient CMD in an Irish family who in addition to the characteristic white matter abnormalities on neuroimaging, had occipital dysplasia. Clinical, electrophysiological muscle biopsy findings and neuroimaging were very similar in both cases. Although merosin-deficient CMD with white matter abnormalities on neuroimaging is well documented in the literature, the association with occipital dysplasia has only rarely been reported. The appearance of an identical cortical defect in these siblings suggests an underlying genetic mechanism.     

Black tea and mammary gland carcinogenesis by 7,12- dimethylbenz[a]anthracene in rats fed control or high fat diets

Epidemiological studies suggest that tea may reduce cancer risk, and in laboratory rodents, chemopreventive effects of tea or purified extracts of tea have been demonstrated in lung, gastrointestinal tract and skin. There is some evidence of chemoprevention by tea in the mammary gland, but the data are not conclusive. In order to evaluate more fully the possible influence of black tea on 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary gland tumors in the female S-D (Sprague-Dawley) rat, three large studies were performed: experiment 1, tumorigenesis in rats fed AIN-76A diet and given 25 mg/kg DMBA and 1.25 or 2.5% whole tea extract or water to drink; experiment 2, tumorigenesis in rats given 15 mg/kg DMBA and the same diet and fluids as in experiment 1; experiment 3, tumorigenesis in rats fed control or HF (high fat, corn oil) diet and given 15 mg/kg DMBA and 2% tea or water to drink. Tea was given throughout the experiment; DMBA was given by gastric gavage at 8 weeks of age. There was no consistent effect of tea on tumorigenesis in rats fed AIN-76A diet; there was, however, evidence in experiment 3 of a reduction of tumorigenesis by tea in rats fed the HF diet. In experiment 3, rats fed the HF diet and given water showed the expected increase in tumor burden (number and weight) compared with rats fed control diet. However, rats fed the HF diet and given 2% tea showed no increase in tumor burden; their tumor burden was significantly lower than in rats fed the HF diet and given water (P < 0.01) and was not different from rats fed control diet and given water or tea. In addition, in experiment 3, the number of malignant tumors per tumor- bearing rat was increased by the HF diet in water-drinking rats (P < 0.01) but not in tea-drinking rats. Therefore, it appears that tea partially blocked the promotion of DMBA-induced mammary tumorigenesis by the HF diet.