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Biomedical subjects

J Katz

Publications and source records attributed to J Katz.

At least 253 records · Page 14Linked to original sources
PubMed1995

The prevalence of blindness and visual impairment among nursing home residents in Baltimore.

BACKGROUND: Although the prevalence of blindness and visual impairment increases with age, most surveys of ocular disease do not include nursing home residents. METHODS: We conducted a population-based prevalence survey of persons 40 years of age or older residing in nursing homes in the Baltimore area. Of 738 eligible subjects in 30 nursing homes, 499 (67.6 percent) participated in the study. They had their eyes examined and their visual acuity tested and were interviewed in detail. The nonparticipants were more likely to be older, to be white, and to have lower scores on the Mini-Mental State Examination. RESULTS: The prevalence of bilateral blindness (visual acuity < or = 20/200) was 17.0 percent. The prevalence of visual impairment (< 20/40 but > 20/200) was 18.8 percent. The frequency of blindness increased from 15.2 percent among those under 60 years of age to 28.6 percent among those 90 or older. The age-adjusted prevalence of blindness was 50 percent higher among blacks than among whites (P < 0.01). As compared with the noninstitutionalized population from the same communities, the rate of blindness among nursing home residents was 13.1 times higher for blacks and 15.6 times higher for whites. Cataract was the leading cause of blindness, followed by corneal opacity, macular degeneration, and glaucoma. We judged that 20 percent of the functional blindness and 37 percent of the visual impairment could be remedied by adequate refractive correction. CONCLUSIONS: Blindness and visual impairment are highly prevalent among nursing home residents. Much of this loss of vision could be treated or prevented with appropriate ophthalmologic care.

Adult↗
PubMed1995

Hypertension, perfusion pressure, and primary open-angle glaucoma. A population-based assessment.

OBJECTIVE: To evaluate the association of vascular factors with primary open-angle glaucoma (POAG). DESIGN: A population-based prevalence survey of ocular disease among black and white residents. SETTING: Communities of east Baltimore, Md. PARTICIPANTS: A stratified cluster sample of 5308 residents 40 years of age or older. MAIN OUTCOME MEASURES: Primary open-angle glaucoma as defined by demonstrable glaucomatous optic nerve damage based on visual fields and/or optic disc findings. Intraocular pressure level was not a criterion for diagnosis. RESULTS: Systolic and diastolic blood pressure showed modest, positive association with POAG. The effect of blood pressure on POAG was modified by age, with a stronger association among older subjects. Lower perfusion pressure (blood pressure-intraocular pressure) was strongly associated with an increased prevalence of POAG, with a sixfold excess for those in the lowest category of perfusion pressure. CONCLUSION: These results suggest that POAG is associated with an alteration in factors related to ocular blood flow and a breakdown of autoregulation.

Adult↗
PubMed1995

Epidemiology of xerophthalmia in Nepal. A pattern of household poverty, childhood illness, and mortality. The Sarlahi Study Group.

A case-control study of xerophthalmia (120 cases, two with corneal disease; 3377 children without xerophthalmia, 12 to 60 months of age) was conducted in the rural plains of Nepal. Relative household wealth (ownership of animals and goods, house quality) and social standing (parental education, nondaily laboring, more affluent castes) were inversely related to risk of xerophthalmia. Mothers of cases were more likely to have had children die than mothers of controls (odds ratio, 1.85; 95% confidence interval, 1.22 to 2.78); case households were more likely to have had a young child die in the past year (odds ratio, 2.85; 95% confidence interval, 1.43 to 5.67). Children with xerophthalmia were more wasted and stunted than controls, although these associations largely disappeared after adjusting for socioeconomic influences. Frequency of breast-feeding was highly protective against xerophthalmia in a dose-response manner (odds ratio, 0.32 for 1 to 10 times a day, 0.12 for > 10 times a day) after adjusting for age and other factors. The risk of xerophthalmia rose directly with reported duration of dysentery in the previous week (odds ratio, 2.13 and 5.81 for durations of 1 to 6 days and > or = 7 days, respectively, vs none). Mild xerophthalmia is reflective of a lower, local standard of living within which child health, nutrition, and survival are compromised.

Case-Control Studies↗
PubMed1995

Neural rim area declines with increased intraocular pressure in urban Americans.

OBJECTIVE: To determine intraocular pressure (IOP)-related differences in the neural rim area among urban Americans without known optic nerve disease. DESIGN: Population-based prevalence study conducted in 16 cluster areas in East Baltimore, Md. PARTICIPANTS: A population-based sample of 1521 black and 1851 white individuals aged 40 years and older without evidence of optic nerve disease. MAIN OUTCOME MEASURE: Intraocular pressure-related differences in neural rim area, neural rim area-to-disc area ratio, and cup-to-disc ratio. RESULTS: We analyzed optic disc photographs using the Imagenet system (Topcon Instrument Corp of America, Paramus, NJ). After adjusting for age and disc area, white Americans had a 6% decrease in neural rim area for every 10-mm Hg increase in IOP (P = .0001). In black Americans, there was a quadratic relationship between neural rim area and IOP, with little decline with IOP up to approximately 17 mm Hg, after which neural rim area declined significantly with higher IOP (P = .001). Similarly, the neural rim area-to-disc area ratio decreased and the vertical cup-to-disc ratio increased with increasing IOP in both black and white Americans. CONCLUSIONS: The higher the level of IOP, the smaller was the amount of neural rim tissue in the optic disc for both black and white Americans. However, the relationship between IOP and neural rim area was different in whites and blacks.

Adult↗
PubMed1995

The use of interferon alfa-2a for life-threatening hemangiomas.

Hemangiomas are the most common benign neoplasm in the neonatal period. While most small hemangiomas involute spontaneously, up to 20% may grow to a massive size and never completely involute. Massive hemangiomas are also frequently associated with life-threatening complications, such as airway obstruction, platelet trapping (Kasabach-Merritt syndrome), and high-output heart failure. The use of interferon alfa-2a for the treatment of massive hemangiomas not responsive to traditional therapy has recently been reported. We present the successful use of interferon alfa-2a in a series of five patients with massive hemangiomas complicated by airway compromise, congestive heart failure, need for tracheotomy, Kasabach-Merritt syndrome, and failure to thrive, despite traditional therapy.

Airway Obstruction↗
PubMed1995

Cytokines and growth factors modulate cell growth and insulin-like growth factor binding protein secretion by the human salivary cell line (HSG).

The human salivary cell line (HSG) was investigated for the effect of various growth factors and cytokines on cellular proliferation and on the production of insulin-like growth factor binding proteins (IGFBPs). IGF-I increased cell growth by approximately 25%, and induced the appearances of three distinct protein bands on ligand blot of the cell culture. Two bands with molecular weights of 43 and 45 Kda, respectively, proved to be IGFBP-3 using a specific antibody, and the third was a 24 Kda species (probably, IGFBP-4). Similar IGFBPs were released by the cells following stimulation by EGF and insulin as well as following incubation with the IGF-I receptor antibody alpha IR3. Retinoic acid had an inhibitory effect (50%) on IGF-I-induced cellular proliferation and an attenuative effect on the 24 Kda band when it was combined with IGF-I, and to a lesser effect EGF; however, it enhanced IGFBP-3 production when incubated with IGF-I. The IGF-I receptor antibody had an agonistic effect on IGFBPs production when applied alone or together with IGF-I. TNF-alpha and INF-gamma had minimal effects on cell growth when added alone but when applied in combination, a marked inhibition of cellular proliferation was noted. These cytokines caused increased accumulation of IGFBP-3, -4, and -5. Addition of IGF-I to these cytokines enhanced the expression of these bands. These data demonstrate that growth factors and cytokines which modulate HSG cell growth, induce specific IGFBPs which may play a role in their effects on cell growth.

Cell Division↗
PubMed1995

Identification of denatured double-stranded DNA by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

We created double-stranded DNA (dsDNA) by annealing synthetic oligonucleotides and used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to measure the difference in molecular weight of the complementary strands after denaturation. Refined sample preparation and deliberate rectilinear construction at a linear mass spectrometer produced a mass resolution exceeding 1000 for single-stranded DNA. We present methodologies and demonstrate the potential for analysing dsDNA by determining the mass of the complementary strands.

Base Sequence↗
PubMed1995

Breakthrough of single-quantum coherence and its elimination in double-quantum filtering.

Breakthrough of single-quantum coherence is shown to occur after application of a double-quantum filter with the conventional four-step phase-cycling scheme. This single-quantum breakthrough is due to the intersequence stimulated echo which has been generated by the radiofrequency pulses in the preceding pulse sequence and appears at the same time as the double-quantum coherence signal in the current pulse sequence. Moreover, the phase of the intersequence stimulated echo is the same as the phase of the double-quantum coherence signal; i.e., the phase of the intersequence stimulated echo is twice the phase change of the radiofrequency pulses in the creation period when their phase is rotated in accordance with the conventional four-step phase-cycling scheme. Consequently, the intersequence stimulated echo passes through the double-quantum filtration in the conventional four-step phase-cycling scheme and gradient pulses. A new phase-cycling scheme which can filter out the single-quantum breakthrough signal is proposed here and its effectiveness is verified experimentally and by computer simulations.

Computer Simulation↗
PubMed1995

Incidence of acute angle-closure glaucoma after pharmacologic mydriasis.

PURPOSE: To study the incidence of acute angle-closure glaucoma secondary to pupillary dilation and to identify screening methods for detecting angles at risk of occlusion. METHODS: We studied 5,308 respondents to the Baltimore Eye Survey, a cross-sectional, population-based survey conducted in a multiracial urban community. We measured incidence of acute angle-closure glaucoma after pharmacologic mydriasis and the specificity and sensitivity associated with three screening criteria in identifying those with potentially occludable angles. The screening factors were presence of shallow anterior chamber on penlight examination, history of glaucoma, and blindness. RESULTS: Of the 4,870 subjects whose eyes were dilated on screening examination, none developed acute angle-closure glaucoma. However, 38 patients of the 1,770 who were referred for definitive eye examination were judged to have occludable angles on the basis of gonioscopic methods. Of note, subjects aged 70 years and more were three times more likely to have occludable angles than those aged 40 to 69 years (P < .004) In 14 black subjects with occludable angles, six were detected by history of glaucoma and not by shallow anterior chamber configuration; alternatively, in 24 white subjects, 11 (46%) were detected on the basis of shallow anterior chambers (Fisher's exact test, P = .014). When the three screening factors were considered alone and in combination, the most effective combination for predicting a potentially occludable angle was to use shallow anterior chamber on penlight examination and history of glaucoma. These criteria provide 60.5% sensitivity and 93.3% specificity. CONCLUSION: If screening is performed accurately and the results are negative, the risk of dilating a potentially occludable angle was less than one in 333 subjects (negative predictive value, 0.997) in this population.

Acute Disease↗
PubMed1995

Diabetes, intraocular pressure, and primary open-angle glaucoma in the Baltimore Eye Survey.

BACKGROUND: The association of diabetes with primary-open angle glaucoma (POAG) has been controversial and often confused by varying definitions of both diabetes and POAG. The purpose of this study is to evaluate this association in a population-based sample of subjects from the Baltimore Eye Survey. METHODS: A stratified sample of residents in 16 cluster areas of east Baltimore was recruited for a detailed ophthalmologic screening examination. A total of 5308 black subjects and white subjects participated. Of these participants, 161 received a diagnosis of POAG. During a detailed interview with each subject, diabetes was defined based on a reported history of diabetes. Persons with diabetes were classified as "insulin-users" and "noninsulin-users" based on their current method of treatment. RESULTS: Diabetes was highly prevalent in this population, with 10.6% of white subjects and 17.2% of black subjects reporting a positive history. Diabetes was associated with higher intraocular pressure, but differences were not large (means, 17.4, 18.0, and 17.8 mmHg) among subjects without diabetes, those with diabetes who were not using insulin, and those with diabetes who were using insulin, respectively. Diabetes was not associated with POAG (age-race-adjusted odds ratio, 1.03; 95% confidence interval, 0.85, 1.25). This was true for both types of diabetes. Persons whose POAG had been diagnosed before the examination showed a positive association with diabetes (odds ratio, 1.7, 95% confidence interval, 1.03, 2.86), indicating that selection bias could explain the positive results of previous clinic-based investigations. CONCLUSION: There is no evidence from this population-based investigation that supports an association between diabetes and POAG.

Adult↗
PubMed1995

Automated perimetry detects visual field loss before manual Goldmann perimetry.

PURPOSE: To determine if automated perimetry detects visual field defects before manual Goldmann perimetry. METHODS: Subjects with ocular hypertension without field loss on detailed manual perimetry were followed prospectively with annual automated and manual perimetry. Subjects with field loss on manual perimetry were age-matched post hoc to subjects who did not have field loss. The automated fields 1 year before the development of field loss on manual perimetry were compared between the two groups. Subjects were recruited from ophthalmologists' offices, eye clinics, and a population-based glaucoma survey in the Baltimore area. Abnormal results detected on the Humphrey Field Analyzer were defined using the glaucoma hemifield test, mean defect, and corrected-pattern standard deviation. RESULTS: Forty subjects who had field loss during 8 years of follow-up were compared with 145 control subjects with ocular hypertension who did not have defects. Seventy-five percent of converters had abnormal results of the glaucoma hemifield test 1 year before field loss on manual perimetry, whereas 22% of controls had abnormal results of the glaucoma hemifield test (odds ratio, 13.4). The odds ratio of field loss developing on manual perimetry within 12 months was 3.3 for those with borderline results of the glaucoma hemifield test relative to the control subjects. The odds ratio was 6.0 for corrected-pattern standard deviation (P < 0.05) and 3.9 for mean deviation (P < 0.05). CONCLUSIONS: Those with field loss on manual perimetry were more likely to have had an abnormal automated field 1 year before conversion than those who did not convert. However, 22% of subjects in whom definitive field loss did not develop on manual perimetry during the study had abnormal automated fields at one visit and 15% had abnormal automated fields on two consecutive visits.

Aged↗
PubMed1995

Sample-size implications for population-based cluster surveys of nutritional status.

We studied the design effects for population-based surveys that estimated the prevalence of wasting and stunting malnutrition in Malawi, Zambia, Indonesia, and Nepal, and studied the magnitude of different types of malnutrition clustering within villages. Weight, height, and midupper-arm circumference were measured on all children or on systematic samples of children in randomly selected villages. Design effects ranged from 0.53 for low height-for-age in Zambia to 6.12 for low weight-for-age in Nepal. If all sampled clusters were of size 30, as is often the case for nutrition surveys, design effects would have ranged from 0.44 for low height-for-age in Zambia to 2.59 for low midupper-arm circumference in Zambia. Malnutrition did cluster within villages. Stunting malnutrition clustered less than did wasting malnutrition. Nutrition surveys using clusters of 30 can sample fewer clusters than currently recommended if basic prevalence and cluster information are available prior to sample selection.

Anthropometry↗
PubMed1995

Mortality of infants < 6 mo of age supplemented with vitamin A: a randomized, double-masked trial in Nepal.

The effect of supplementing 11,918 infants < 1 mo and 1-5 mo of age with vitamin A (15,000 and 30,000 micrograms retinol equivalents or 50,000 and 100,000 IU, respectively) or a placebo on subsequent 4-mo mortality was assessed in a randomized, double-masked community trial in the rural plains of Nepal. There were 130 deaths (51.6/1000 child-y) in the control group and 150 deaths (57.1/1000 child-y) in the vitamin A group, yielding a relative risk of 1.11 (95% CI: 0.86, 1.42), which is indicative of no overall effect on early infant mortality. There was a tendency for the relative risk of mortality among vitamin A recipients to rise with improved nutritional status. These results suggest that distribution of a large oral dose of vitamin A to infants < 5-6 mo of age may not benefit short-term survival. This is in contrast with the results of trials in which older infants and children in this same population were supplemented.

Diarrhea↗
PubMed1995

Night blindness is prevalent during pregnancy and lactation in rural Nepal.

The prevalence of night blindness during pregnancy and lactation was assessed in a sample of 426 women living in the rural terai of Nepal. These women were also examined for ocular signs of vitamin A deficiency. Among 241 lactating women, 16.2% reported experiencing night blindness at some time during the pregnancy that produced the infant they were now breast-feeding. Among 185 pregnant women, 8.1% reported being night-blind at the time of the interview. The odds of night blindness in the current pregnancy were six times greater for women who reported night blindness in their previous pregnancy. Night-blind women were more likely to come from households with lower socioeconomic status. Teenage women and those over the age of 30 were at highest risk, particularly those of higher parity within these age groups. Vitamin A deficiency, for which night blindness is a marker, seems to be a problem in this population of pregnant and lactating women, with potential health consequences for women and their infants.

Adolescent↗