Biomedical subjects
Publications and source records attributed to A Sommer.
Lyme disease is a cause of illness involving multiple organ systems, including, in 10-15 % of cases, the nervous system. Peripheral radiculoneuritis, cranial neuritis, encephalitis and myelitis are among the neurological manifestations found in the second and third stages. We present the MRI findings in isolated oculomotor nerve involvement by Lyme disease and discuss the differential diagnosis.
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PURPOSE: The authors estimated the prevalence and rates of progressive visual field loss in glaucoma patients followed annually for a median of 6.3 years. METHODS: Linear regression was used to estimate rates of progression of mean deviation, corrected pattern standard deviation (CPSD), clusters of locations based on the Glaucoma Hemifield Test (GHT), and location specific changes in C-30-2 fields of the Humphrey Analyzer. RESULTS: Sixty-seven eyes of 56 patients whose first two consecutive fields were abnormal on GHT were included. Almost all patients were under treatment or had undergone surgery for glaucoma. Visual field deteriorated in 19 (28%) eyes based on worsening of one or more CPSD, GHT clusters, or individual test locations (regression slopes significantly different from zero). Corrected pattern standard deviation deteriorated in 5 eyes, at least one GHT cluster deteriorated in 17 eyes, and one or more individual test locations deteriorated in 15 eyes. For those whose visual field deteriorated, CPSD increased by 0.9 dB/year. Glaucoma Hemifield Test clusters declined by between 1.4 and 2.4 dB/year. Deterioration at individual locations ranged from 1.0 to 5.0 dB/year. Age, but not baseline visual field severity, was predictive of further visual field loss. The odds ratio for the association between progressive visual field loss and thinning of the nerve fiber layer was 1.81 (95% confidence interval: 0.52, 6.33), and 3.78 (95% confidence interval: 0.80, 18.16) for the association between progressive visual field loss and optic disc changes during follow-up based on masked photograph readings. CONCLUSIONS: Less than one in three eyes of patients with glaucoma had any progressive field loss. Average changes in threshold sensitivities of less than 1 dB/year could not be detected with seven fields done over 6 years. Larger changes or increased frequency of visual field testing would need to occur before smaller changes could be detected statistically.
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PURPOSE: Revolutions in the health care marketplace, with their implied dependence upon the population perspective, have renewed interest in epidemiologic methods and their application. METHODS: As a way of organizing questions, data, and answers, epidemiology is once again the core scientific discipline for a multidimensional paradigm shift that emphasizes five facets of health care. First, the health of enrolled populations, rather than merely treatment of sick individuals presenting for care. Second, assessment of the "time, place, and person" of disease burden--who is healthy, who is not, and what it will take to maximize their health. Third, the causative factors for disease and the factors or characteristics that promote health. Fourth, the development of evidence-based clinical guidelines for clinicians and consumers alike. Fifth, evaluation of the impact providers are having on the health of populations (outcomes), individually and collectively. RESULTS: Thoughtful consideration of all of the above factors depends upon epidemiologic data and insights brought to a firm and conclusive end point capable of supporting policy. CONCLUSIONS: Credibility will require that epidemiologists (and the symbiotic media) exercise far greater restraint in drawing definitive conclusions and speculations from often starting but meager data.
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Two hundred seven vitamin A-deficient southern Indian children aged 1-7 y (mean age: 56.9 mo) underwent testing of dark-adapted visual and pupillary thresholds in their village setting according to a previously reported protocol. One hundred thirty (62.8%) of the children also underwent serum retinol testing, and 178 (86.0%) participated in a randomized, placebo-controlled vitamin A dosing trial with pre- and postdose testing of dark-adaptation threshold. Most subjects (184 of 207, 88.9%) were able to complete pupillary testing, an objective sign requiring minimal cooperation, including a high proportion of the youngest children (72.2% of subjects aged 2 y). The proportion of children completing visual threshold testing, which requires greater understanding and cooperation, was significantly smaller than that able to complete pupillary testing (131 of 207, 63.3%; P < 0.0001, chi square). At baseline (predosing), the mean serum retinol concentration declined in linear fashion with a higher pupillary threshold (0.73 mumol/L with a score < or = 4; 0.47 mumol/L with a score > or = 8; P < 0.01). The mean pupillary threshold for these highly vitamin A-deficient Indian children (-0.622 log cd/m2) was significantly higher than that for 136 more moderately deficient Indonesian children (-0.985 log cd/m2; P < 0.001, two-sample t test) and 56 normal American children (-1.335 log cd/m2; P < 0.0001, two-sample t test). The improvement in pupillary dark-adaptation testing was not significant for children receiving vitamin A or placebo, though there was a nonsignificant trend toward greater improvement in children receiving vitamin A (P = 0.2, two-sample t test). Pupillary threshold testing represents a new, noninvasive, practical, and seemingly valid approach to assessing the vitamin A status of a moderately to severely deficient preschool population.
Inconsistencies have been observed in the impact of vitamin A (VA) supplementation on early child growth. To help clarify this issue, a cohort of 3377 rural Nepalese, nonxerophthalmic children 12-60 mo of age were randomized by ward to receive vitamin A [60,000 microg retinol equivalents (RE)] or placebo-control (300 RE) supplementation once every 4 mo and followed for 16 mo. VA had no impact on annual weight gain or linear growth. However, arm circumference (AC) and muscle area (MA) growth improved in VA recipients, by 0.13 cm and 25 mm2, respectively, over controls. Growth of children with xerophthalmia, who were treated with >/= 120, 000 RE at base line, was also compared to that of nonxerophthalmic children, stratified by initial wasting status, and adjusted for sex, baseline age and measurement status. Among initially nonwasted children (AC >/= 13.5 cm), VA-treated xerophthalmic children (n = 86) gained 0.7 cm more in linear growth than nonxerophthalmic children. Among initially wasted children (AC < 13.5 cm), VA-treated children (n = 34) gained additional weight (672 g), height (approximately 1 cm), muscle (76 mm2) and fat (79 mm2) areas, and subscapular skinfold (1.3 mm) compared to changes observed in nonxerophthalmic children. Relative increments in soft tissue growth occurred within 4 mo of VA treatment, while the effect on linear growth was gradual. Moderate-to-severe VA deficiency, marked by xerophthalmia, is likely to impair normal physical growth, but milder stages of deficiency may not have this effect in rural South Asia.
BACKGROUND: Leg telangiectasias are visible, ectatic dermal arteriols, capillaries, or veins with a diameter of 0.1-1 or 2 mm. Their origin is still not known and different opinions have been published. OBJECTIVE: In our study we were interested in the different colors of telangiectasias and we wanted to demonstrate whether a difference in blood gases is causing the difference in color between red and blue telangiectasias. METHODS: We measured a capillary astrup in 20 patients, who had red as well as blue telangiectasias on the lower limb. Therefore, we took two samples, one of a red and one of a blue telangiectasia. By this we measured the oxygen saturation and the carbon dioxide concentration of the samples. Furthermore, we introduced the appearance of telangiectasias in two rather newly developed techniques, such as high-frequency 20- and 50-MHz ultrasound and laser Doppler perfusion imaging (LDPI). RESULTS: Red telangiectasias of all 20 patients had an average oxygen concentration of 5.9 kPa, (range, 3.94-7.46 kPa); their average CO2 concentration was 5.45 kPa (range, 4.54-7.06 kPa). Blue telangiectasias had an average oxygen concentration of 5.11 kPa (range, 3.12-7.0 kPa); their average CO2 concentration was 6.07 kPa (range, 5.38-7.36 kPa). Statistically work-up with a paired student's t-test showed a higher oxygen saturation of the red telangiectasias and a higher carbon dioxide concentration of the blue vessels. CONCLUSION: As telangiectasias are assumed to be located in the capillary bed, the reason for differences in oxygenation could possibly be found in underlying physiological and anatomical principles of the capillary loops with the red telangiectasia representing the arterial loop of the capillary and the blue telangiectasia representing the venous loop of the capillary. With high frequency ultrasound and LDPI it is possible to get useful information for finding the underlying feeder veins, which "feed" the superficial telangiectasias. Injecting into the nutritional vessel telangiectases can potentially decrease the number of side effects and, may reduce the number of necessary injections.
Fabry's disease is an X-linked hereditary disorder resulting in accumulation of a glycolipid (galactosylgalactosyl glucosylceramide) due to deficiency of alpha-galactosidase A. The diagnosis can be made by histopathologic examination of skin biopsy, low activity of alpha-galactosidase in leucocytes and genetic examination. Treatment is symptomatic. We want to stress the multidisciplinary collaboration necessary to deal with this condition, in order to prevent acceleration of symptoms.
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PURPOSE: To estimate the prevalence of refractive errors among adult black and white Americans and to identify risk factors associated with these refractive errors. METHODS: Refractive error was measured in a population-based sample of black and white adults age 40 or older residing in east Baltimore from 1985 through 1988. Aphakic eyes were excluded from analysis. RESULTS: The prevalence of myopia varied from 10.5% among black men 80 years and older to 42.1% among white women 40 to 49 years of age. Hyperopia ranged from 11.8% among black men 40 to 49 years to 68.1% among white men 80 years of age and older. Astigmatism ranged from 15.8% to 45.2%, and anisometropia ranged from 2.8% to 8.1%, depending on age, race, and gender. Black persons had less myopia, hyperopia, astigmatism, and anisometropia than did white persons. Myopia (< -0.5 diopter [D] spherical equivalent) declined with age, whereas hyperopia (> +0.5 D), astigmatism (> 0.5 D of cylinder), and anisometropia (> 1.0 D between eyes) increased with age. Myopia increased with increasing years of education, although this association was stronger for white persons than for black persons and among younger subjects. Hyperopia declined with increasing years of education, and this association was stronger among younger than older subjects. Education was not associated with astigmatism or anisometropia. CONCLUSIONS: Black persons had lower rates of refractive error than did white persons, except for hyperopia prevalence, which was comparable in black and white women. Refractive errors are common among adult inner city Americans, but rates vary substantially by age, race, gender, and education levels.
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The activity and the voltage dependence of the inorganic pyrophosphatase (PPase) was measured on intact vacuoles of Chenopodium rubrum cells using the patch-clamp technique. With K+ at the cytoplasmic side a negative current representing the forward mode of the pump was measured after addition of pyrophosphate (PPi). The pump was reversed and a positive current was detected after addition of orthophosphate (Pi) in the presence of K+ at the vacuolar side when a pH gradient across the tonoplast was applied. The PPase operates as a constant current source, because no voltage dependence was observed (-60 to 60 mV). The K+ dependence of the PPi-induced current was investigated by substitution of cytoplasmic K+ by other cations. The selectivity sequence was: K+ > or = Rb+ > NH4+ = Cs+ > Na+ > Li+ = choline+, and was independent of the membrane voltage and pHcyt. With Cs+ or Li+ in the bath and K+ inside the vacuole the PPi-induced current became voltage-dependent, and positive currents were observed even if the pump was geared to operate in the forward mode. We suggest a "tunneling' effect through a channel-like domain in the PPase molecule which, under defined electrochemical gradient conditions and in the presence of PPi, allows K+ ions to cross the energy barrier usually separating the cytoplasmic from the vacuolar face of the pump.
A 711-bp cDNA encoding a cysteine proteinase inhibitor (cystatin) was isolated from a cDNA library prepared from 7-10 cm Sorghum bicolor seedlings. The nearly full-length cDNA clone encodes 130 amino acid residues, which include the Gin-Val-Val-Ala-Gly motif, conserved among most of the known cystatins as a probable binding site for cysteine proteinases. The amino acid sequence of sorghum cystatin deduced from the cDNA clone shows significantly homology to those of other plant cystatins. The sorghum cystatin expressed in E. coli showed a strong papain-inhibitory activity.