Biomedical subjects

H A Feldman

Publications and source records attributed to H A Feldman.

At least 73 records · Page 4Linked to original sources

PubMed1993

Oral health status of the elderly in New England.

The New England Elders Dental Study (NEEDS) reports the prevalence, extent and severity of oral diseases and conditions among a representative sample of community-dwelling elders age 70 and older residing throughout the six New England states. In-home, full-mouth examinations were conducted by four calibrated dentists who used National Institute of Dental Research (NIDR) standardized disease measures plus additional diagnostic codes on all tooth surfaces. Only 37.6% of elders age 70 and older were edentulous, while dentate elders had a mean number of teeth per person ranging from 21.5 to 17.9 across age and gender cohorts. The prevalence of untreated coronal decay in elders with teeth was 28% in female elders and 34% in male elders. More than 90% of all elders with teeth had coronal fillings and 22% exhibited untreated root caries. Periodontal destruction was substantial, with 66% of dentate elders exhibiting moderate periodontal pockets (4-6 mm) while 21% exhibited severe periodontal pocketing (> 6 mm). Comparisons with national surveys suggest that periodontal disease prevalence and severity appear to have been underestimated in previous national studies of the elderly. Because of aging and tooth retention trends, the periodontal disease problem of the elderly may be increasing in the face of dentists' tendency to underdiagnose the periodontal diseases, legal constraints on dental hygienists to independently treat them, and inadequate funding for conservative nonsurgical therapies.

Aged↗

PubMed1993

Oral disease and physical disability in community-dwelling older persons.

OBJECTIVE: The aim of this epidemiologic investigation was to determine whether poor oral health in older persons was associated with physical disability. DESIGN: The study was a cross-sectional survey involving in-home interviews and dental examinations of older persons. SETTING: A random sample of 68 cities and towns was selected from the six New England states, with stratification according to population size. PARTICIPANTS: The study sample consisted of 1,156 community-dwelling (non-institutionalized) individuals aged 70 and over, randomly selected from the Medicare beneficiary lists for each city and town. MEASUREMENTS: Oral health was assessed by three dichotomous indices: edentulism (no teeth); current caries, including either coronal or root decay; and periodontal disease, as measured by gingival pocket depth. Physical disability was indicated by the subject's self-report of difficulty in the areas of personal care (eating, bathing, dressing, and using the toilet) and mobility (walking, bed transfer, getting outside). Additional independent variables included age, sex, number of teeth, education, living alone, oral hygiene practices, and time since last dental visit. RESULTS: We found a direct association between specific areas of physical disability and current caries and edentulism. The risk of poor oral health did not increase with advancing age once the related risk factors were controlled for. Those subjects with mobility disabilities were at increased risk of tooth loss; those with personal care limitations were at increased risk of current caries. CONCLUSIONS: Physical disability should be added to the list of known risk factors for oral disease among the older population. Our findings call attention to the need for health care providers to screen for oral health problems among disabled older persons. Further gerontologic research is needed to identify the mechanisms linking physical disability with oral disease in older persons.

Activities of Daily Living↗

PubMed1993

Beneath the surface of coronal caries: primary decay, recurrent decay, and failed restorations in a population-based survey of New England elders.

A cross-sectional study was conducted of the oral health status of a random sample of community dwelling elders, aged 70 and older, living within the six New England states. Four examining teams, each composed of a trained and calibrated dentist and a field technician, collected data during an in-home oral examination. The prevalence of carious, filled, recurrent decayed, and non-carious but failed restored coronal surfaces was recorded. For the 1,151 respondents, the mean DFT was 6.16 (SD = 6.96) and the mean DFS was 18.83 (SD = 23.37), with 37.6 percent of the sample edentulous. Eleven percent of the population had 70 percent of the coronal decay. Males (OR = 2.2, CI = 1.3-3.8) and elders with less education (OR = 1.8, CI = 1.0-3.0) were at higher risk for three or more surfaces of coronal decay. Recurrent decay was present in 16 percent of the dentate population. However, more noncarious but failed restored coronal surfaces (332) were recorded in the population of New England elders than were surfaces of recurrent decay (234). The New England elders have higher rates of decay than New England children, although the rates matched those of previous national studies. The findings signal a need to develop targeted preventive regimens for older adults and greater understanding of dental treatment needs of elders.

Aged↗

PubMed1993

Developmental changes in diaphragm contractile properties.

The contractile properties of pre- and early postnatal respiratory muscles are incompletely understood. We examined the effects of development on isometric contractile properties, with an emphasis on properties at 37 degrees C. One-day-old (n = 10), 3-wk-old (n = 10), and adult (n = 10) rabbits were studied. Isometric contractile properties of costal diaphragm strips were measured in vitro by using direct stimulation. Twitch and maximal, i.e., fused, tetanic force production increased with strip dimension and with age. Maximal tetanic force developed per unit cross-sectional area (stress) was significantly decreased in muscle from 1-day olds, whereas it was greatest in muscle from 3-wk olds. Twitch stress was similar in all three groups. Only when the stimulus duration was prolonged did twitch and fused tetanic force achieve maximal values values for the 1-day-old and 3-wk-old strips, suggesting less effective excitation-contraction coupling in those muscles. We conclude that immature rabbit diaphragm has unique isometric contractile properties and stimulus parameter requirements that cannot be deduced from studies using mature diaphragm.

Animals↗

PubMed1993

Tobacco use: a modifiable risk factor for dental disease among the elderly.

OBJECTIVES: Because the public health literature contains few analytic studies of modifiable behavioral risk factors for dental disease among older community-dwelling populations, the New England Elders Dental Study was undertaken as an epidemiologic study of the oral health status of a representative sample of older adults living within the six New England states. METHODS: Five dentists conducted comprehensive in-home oral health examinations on 1156 community-dwelling adults aged 70 and older to determine whether lifetime use of tobacco products was a significant risk factor for tooth loss, caries, and periodontal disease. RESULTS: Among New England elders, tobacco use was more common among men (18.1%) than women (7.9%), with a combined rate of 12.3%. Further, 64.7% of men and 36.6% of women were previous tobacco users. Years of exposure to tobacco products was a statistically significant risk factor for tooth loss, coronal and root caries, and periodontal disease, regardless of other social and behavioral factors. CONCLUSIONS: Lifelong tobacco use is a modifiable risk factor for poor dental health among older adults. Dental practitioners need to intervene with all their adult patients to discourage use of tobacco products for oral as well as general preventive health care.

Aged↗

PubMed1992

Environmental endotoxin measurement: the Kinetic Limulus Assay with Resistant-parallel-line Estimation.

A Limulus assay method was specifically designed for environmental endotoxin aerosols. Application of new statistical and sample preparation methods strengthened the validity and precision of the Limulus test. Statistically, the Kinetic Limulus Assay with Resistant-parallel-line Estimation (KLARE) differed from conventional analytic methods (as used in chromogenic assays and other kinetic methods) by routinely using a dilution series of the unknown sample as well as the standard to compute potency and an estimate of variance for each sample. Analysis of dose-response slopes for the standard and unknowns detected inhibition and enhancement effects--without multiple assay. Concentration-dependent interference and a more complex, concentration-independent interference with the Limulus assay were detected. Resistant regression and a standardized data analysis corrected for concentration-dependent interference. Sample preparation in a buffer eliminated concentration-independent interference and, thus, improved both the validity and the precision of potency measurements. The utility of a sample buffer and of parallel-line analysis, with both turbidimetric and chromogenic lysates, was demonstrated by assay of three control standard LPS and reference LPS (EC5). The limit of detection for endotoxin was less than 1 pg/ml in buffer. Samples containing greater than or equal to 10 pg/ml were measured with a coefficient of variation of approximately 6% in a single assay. Reproducibility of potency estimates for four samples over 3 days was compared on the basis of standard errors of the mean. The conventional method gave on average a CV of 65% while the resistant-parallel-line method gave, on average, a CV of 6%. Also, the conventional method failed to detect interference and, thus, included data from invalid assays. Conventional analysis of environmental aerosol samples was highly sensitive to the choice of dilution factor causing as much as 1000% variation in the result. By contrast, KLARE results changed by at most 30% with similar changes in initial dilution because KLARE was able to detect, and correct for, the influence of interferant compounds.

Aerosols↗

PubMed1991

Kinetics of phagocytosis and phagosome-lysosome fusion in hamster lung and peritoneal macrophages.

The time course of phagocytosis and phagosome-lysosome fusion (PLF) in lung and peritoneal macrophages (LMs and PMs) was measured. Lysosomes in unelicited hamster LMs and PMs were labeled with lucifer yellow. Macrophages then phagocytized heat-killed Saccharomyces cerevisiae (yeast) and were evaluated at several time points for the degree to which yeast particles were adherent vs. internalized and for the presence or absence of PLF as based on the presence or absence of lucifer yellow in yeast-containing phagosomes. A three-compartment model (adherent, ingested, fused) of independent phagocytosis and PLF was developed; the number of yeast particles in each compartment was counted, and rate constants for ingestion and fusion were determined. Comparison of rate constants showed that ingestion was significantly faster in PMs (0.047 +/- 0.005 min-1) than in LMs (0.016 +/- 0.005 min-1) (mean +/- pooled SEM; P less than 0.001). Similarly, PLF was significantly faster in PMs (0.109 +/- 0.013 min-1) than in LMs (0.046 +/- 0.013 min-1) (P less than 0.003).

Animals↗

PubMed1991

Occupational skin disease in newspaper pressroom workers.

Studies of printing industry tradespeople have reported an increased problem of dermatologic abnormalities, including contact dermatitis and dermatitis attributed to solvent exposure. The current cross-sectional health survey of dermatological conditions were conducted in a follow-up of perceived skin abnormalities among newspaper pressroom workers. We surveyed 215 pressroom workers and 34 compositors at a large northeastern US newspaper printing facility. Our findings indicate that printing pressroom workers reported skin condition symptoms at a significantly higher rate than did the compositor referent group. Pressroom workers also were found to be at a significantly elevated risk of developing dermatitis after self-reported exposure to certain commonly used solvents. This emphasizes the need for proper work practices, product substitution where possible, and appropriate protective glove use by newspaper pressroom workers.

Causality↗

PubMed1991

Leukotriene receptor on U-937 cells: discriminatory responses to leukotrienes C4 and D4.

Dimethyl sulfoxide (DMSO)-differentiated U-937 cells develop cell surface receptors for leukotrienes that, when stimulated, initiate a transient increase in intracellular calcium concentration [( Ca2+]i). We investigated the calcium transient that occurs after addition of leukotriene C4 (LTC4) to determine whether it occurs due to 1) the bioconversion of LTC4 to leukotriene D4 (LTD4), which then acts at the LTD4 receptor; 2) the direct action of LTC4 at the LTD4 receptor; or 3) the action of LTC4 at a receptor selective for LTC4. Bioconversion of [3H]LTC4 to [3H]LTD4 was inhibited by 98% when DMSO-differentiated U-937 cells were incubated with 10 mM AT-125 compared with control cells. The dose-response curve for LTC4, with [Ca2+]i as the index of response, was parallel to that for LTD4 but was significantly (P less than 0.0001) shifted 1.6 +/- 0.11 log units to the right. AT-125 did not change the response to LTD4 but the LTC4 dose-response curve was shifted on additional 1.7 logo units to the right. The antagonists SKF 104353 (1 microM) and LY 171883 (10 microM) shifted the dose-response curve for LTD4 3.0 +/- 0.23 and 2.5 +/- 0.23 log units, respectively, to the right and completely inhibited the change in [Ca2+]i due to LTC4 in the presence of 10 mM AT-125. Molecular modeling studies demonstrated a striking difference in the spatial configuration of LTC4 and LTD4, likely accounting for the ability of cell surface receptors to discriminate between the effects of these two molecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Biotransformation↗

PubMed1991

Retention and clearance of 0.9-micron particles inhaled by hamsters during rest or exercise.

We assessed the retention and clearance of inhaled particles in six anatomic compartments of the respiratory tract. Hamsters were exposed for 45 min to 0.9-micron fluorescent latex particles either at rest (n = 9) or while running on a laddermill (n = 9). Oxygen consumption, which was used to estimate minute ventilation, was continuously monitored. Three animals from each group, rest and exercise, were killed at 10 min, 24 h, or 7 days after the exposure. Morphometric techniques were used to determine the number of particles retained in nose and oropharynx (NOSE), trachea and extrapulmonary airways, intrapulmonary conducting airways, respiratory bronchioles, alveolar ducts (AD), and alveoli (ALV). At 10 min, total particle retention increased linearly as a function of O2 consumption (slope = 1.4 +/- 0.3 x 10(6) particles.ml-1.g-1.h-1, P less than 0.015). Exercised hamsters retained 4.4 times more total particles in their NOSE than rested hamsters, but parenchymal retention (AD + ALV) was unaffected. After 7 days, 95% of the particles were cleared from the NOSE, 80% from the trachea and extrapulmonary airways, 44% from intrapulmonary conducting airways and respiratory bronchioles, and 16% from AD and ALV. There was evidence of particle redistribution from AD to ALV during the 1st day. We conclude that exercise enhances the deposition of 0.9-micron particles in the upper respiratory tract but not in the parenchyma. Subsequently, the deposited particles are cleared at varying rates depending on the lung compartment.

Air Pollutants↗

PubMed1991

Intersubject variability in particle deposition does not explain variability in responsiveness to methacholine.

How variable is the deposition of inhaled methacholine (MCH) in the respiratory tract during a challenge test? Does this variability contribute to the variability of airway responsiveness? To examine these questions we estimated the deposition of polydisperse MCH droplets by measuring the deposition of surrogate diethylhexyl sebacate (DEHS) droplets that were similar in size (1.5 microns) but monodisperse. Light scattering photometry and flow measurements were used to compute inspired and expired DEHS particle number. Deposition of DEHS during 4 breaths was measured twice at baseline and after every dose of MCH during an abbreviated challenge test in 16 subjects. Deposition was then compared with reactivity. Reactivity to MCH was expressed as the dose-response slope; it was calculated as percent final change in FEV1/cumulative dose MCH inhaled. Dose-response slopes ranged from zero (nonreactive) to -15.0 (very reactive) %/mumol (mean -3.2 +/- 5.3 SD). Seven subjects had a 20% or greater decrement in FEV1 after their highest MCH dose. Baseline DEHS deposition, which ranged from 66 to 84% (mean 77 +/- 5 SD), was not significantly different between responders and nonresponders and was not a significant predictor of the dose-response slope. Reactivity was significantly associated with an increase in deposition produced by MCH (p less than 0.007). This increase was small, however (relative change less than 7%), so that the effect on the deposited dose of MCH was minimal. We conclude that, with the breathing pattern used, individual differences in DEHS (and MCH) deposition were small and contributed little to intersubject variability of responsiveness to inhaled MCH.

Adult↗

PubMed1991

Age, disease, and changing sex hormone levels in middle-aged men: results of the Massachusetts Male Aging Study.

To evaluate the hypothesis that endocrine profiles change with aging independently of specific disease states, we examined the age trends of 17 major sex hormones, metabolites, and related serum proteins in 2 large groups of adult males drawn from the Massachusetts Male Aging Study, a population-based cross-sectional survey of men aged 39-70 yr conducted in 1986-89. Group 1 consisted of 415 men who were free of obesity, alcoholism, all prescription medication, prostate problems, and chronic illness (cancer, coronary heart disease, hypertension, diabetes, and ulcer). Group 2 consisted of 1294 men who reported 1 or more of the above conditions. Each age trend was satisfactorily described by a constant percent change per yr between ages 39-70 yr. Free testosterone declined by 1.2%/yr, and albumin-bound testosterone by 1.0%/yr. Sex hormone-binding globulin (SHBG), the major serum carrier of testosterone, increased by 1.2%/yr, with the net effect that total serum testosterone declined more slowly (0.4%/yr) than the free or albumin-bound pools alone. Among the major androgens and metabolites, androstane-3 alpha,17 beta-diol (androstanediol; 0.8%/yr) and androstanediol glucuronide (0.6%/yr) declined less rapidly than free testosterone, while 5 alpha-dihydrotestosterone remained essentially constant between ages 39-70 yr. Androstenedione declined at 1.3%/yr, a rate comparable to that of free testosterone, while the adrenal androgen dehydroepiandrosterone (3.1%/yr) and its sulfate (2.2%/yr) declined 2-3 times more rapidly. The levels of testosterone, SHBG, and several androgen metabolites followed a parallel course in groups 1 and 2, remaining consistently 10-15% lower in group 2 across the age range of the study. Subgroup analyses suggested that obese subjects might be responsible for much of the group difference in androgen level. Serum concentrations of estrogens and cortisol did not change significantly with age or differ between groups. Of the pituitary gonadotropins, FSH increased at 1.9%/yr, LH increased at 1.3%/yr, and PRL declined at 0.4%/yr, with no significant difference between groups 1 and 2.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1991

The presence of urinary cellular sediment and albuminuria in newspaper pressworkers exposed to solvents.

To investigate the relationship between exposure to organic solvents and the presence of increased urinary cellular sediment, we conducted a cross-sectional study of 215 newspaper pressroom workers who were exposed to solvent and lubricant mixtures. Thirty-two compositors were surveyed as referents. Industrial hygiene measurements showed low-level airborne exposures to organic solvents (primarily naphthas) and minimal airborne exposure to glycol ethers. There was a high prevalence of solvent-related dermatitis indicating there was significant dermal exposure to these substances. Pressworkers were exposed to solvent mixtures that were associated with dose-related increases in leukocyturia alone or in urinary cellular sediment (erythrocyturia and/or leukocyturia). The presence of urinary cellular sediment was associated with increasing frequency of use of five particular organic solvent mixtures. These results suggest that the increase in urinary cellular sediment may be due, at least in part, to the effects of solvents on the kidney. Consistent with this hypothesis, 16% of pressmen and no compositors were found to have primarily low-grade albuminuria detectable by dipstick. Workers with urinary cellular sediment were significantly more likely to have detectable albuminuria. Albuminuria was more likely to occur with increased frequency of use of four particular solvent mixtures. The presence of urinary cellular sediment was less likely to occur with occasional use of analgesics suggesting a possible etiologic role for acute or chronic urinary tract inflammation.

Adult↗

PubMed1990

Endotoxin measurement: aerosol sampling and application of a new Limulus method.

A new Limulus test was designed specifically for measuring endotoxin in environmental aerosols. The new Limulus method has a detection limit for airborne endotoxin of 2.2 pg (NP-1 activity)/m3 and can precisely quantitate aerosols containing 14 or more pg/m3 from samples representing 6.5 m3 of air. Aerosols in the range 100 to 500 pg/m3 were measured with 95% confidence of +/- 32% and an aerosol of 10 pg/m3 with 95% confidence of +/- 50%. Qualitative information about airborne endotoxin was also obtained from the assay. A wide variety of filter media were found to inactivate lipopolysaccharide in solution. This implies that airborne endotoxin can be measured only relative to the conditions of a particular study and that comparison of endotoxin aerosol measurements made under different circumstances are invalid. The research and policy implications of this observation are discussed. The need for improved collection and extraction methods notwithstanding, it was proposed that a buffered, parallel-line Limulus assay method be adopted as the standard method for measuring environmental endotoxin. The kinetic-turbidimetric Limulus assay with resistant-parallel-line estimates (KLARE), rate response method, should be considered a prime candidate for the standard method because of its precision, sensitivity, resistance to interference by pH, internal validation of estimates, and ability to provide qualitative as well as quantitative information about airborne endotoxin.

Aerosols↗

PubMed1990

Alcohol protects the diaphragm during dietary restriction.

We recently reported that alcoholic rat diaphragm develops greater contractile force than diaphragm of pair-fed control animals. The present experiment examines whether alcohol or dietary restriction is the more likely cause of this surprising finding. We conditioned 10 rats using a liquid diet containing ethanol as 36% of calories. Ten pair-fed control animals received an equal amount of isocaloric, ethanol-free liquid diet. Ten ad libitum control animals had unrestricted access to lab chow and water. Rats were killed after 30 weeks. Left costal diaphragm strips were studied in vitro at optimal length using direct stimulation at supramaximal voltage. Isometric force was measured and divided by muscle cross-section to compute stress. Maximal tetanic stresses developed by muscle from pair-fed controls were systematically less than alcoholic and ad libitum control values (p less than 0.0001); this did not depend on temperature (25 degrees vs. 37 degrees; p greater than 0.50). Pair-feeding increased twitch half-relaxation times (p less than 0.03) and shifted the tetanic stress-stimulation frequency relationship leftward by 10 Hz (p less than 0.01). Diaphragm of pair-fed rats continued to generate lower stresses during the fatigue caused by repeated contractions (p less than 0.01). We conclude that dietary restriction associated with pair-feeding compromises diaphragm performance in rats. Chronic alcohol consumption prevents or reverses these changes, since diaphragm function of alcoholic and ad libitum control animals was not different.

Alcoholism↗

PubMed1990

Toxicity of intratracheally instilled cotton dust, cellulose, and endotoxin.

Cotton dust includes respirable particles containing endotoxin and elastase, agents associated with emphysema. To examine whether a respirable fraction of cotton dust could produce emphysema in an animal model, we intratracheally instilled hamsters with respirable cotton dust particles (0.75 mg/100-g animal), mass median aerodynamic diameter less than or equal to 4.8 microns, twice weekly for 6 wk. We also examined whether instilled endotoxin (255 micrograms/100-g animal) could produce emphysema in hamsters and whether cellulose (0.75 mg/100-g animal) is an appropriate inert comparison dust. A saline-instilled group was the control. Hamsters were killed 8 wk after the last instillation. Static pressure-volume deflation curves of air-filled excised lungs were analyzed to measure lung distensibility. Lungs were fixed in inflation using glutaraldehyde and were examined morphometrically to obtain surface area and numbers of granulomata. Endotoxin-treated animals had increased distensibility, reduced surface-to-volume (S/V) ratio, and morphologically apparent mild centrilobular emphysema. Cellulose-treated animals had decreased distensibility, normal S/V ratio, and significant numbers of granulomata with patchy areas of thickened interalveolar septa. Cotton-dust-instilled animals had normal distensibility, reduced S/V ratio, significant numbers of granulomata, and mild centrilobular emphysema. These data suggest that cotton dust produces a significant parenchymal lesion with elements similar to both the emphysematous response to endotoxin and the fibrotic nodular response to cellulose.

Animals↗

PubMed1989

Pathogenesis of Shigella diarrhea. XIV. Analysis of Shiga toxin receptors on cloned HeLa cells.

Binding kinetics of Shiga toxin to HeLa CCL-2 cells and to cell lines cloned by limiting dilutions were determined. Lines with a wide range of sensitivity to Shiga toxin were obtained. Binding data, analyzed by a computer-based Scatchard model program, revealed two classes of binding sites, one of low affinity and high capacity and one of high affinity and low capacity. The number of high affinity, but not low affinity, sites present on the clones correlated with their sensitivity to toxin. Tunicamycin-treated CCL-2 cells became resistant to Shiga toxin in parallel with a reduction in the capacity of the high-affinity site. Cell content of Gb3, the glycolipid receptor for Shiga toxin, decreased as the sensitivity of the cells diminished. These data show that a minority of Shiga toxin binding sites of HeLa cells are involved in the cytotoxic response and suggest that Gb3 is the high-affinity functional cytotoxin receptor.

Bacterial Toxins↗

PubMed1989

Diaphragm atrophy and weakness in cortisone-treated rats.

Despite frequent therapeutic use, the potential of corticosteroids to produce respiratory muscle myopathy is unknown. We studied effects of chronic steroid treatment on diaphragm mass and function. Eleven Sprague-Dawley rats were treated with cortisone acetate (100 mg.kg-1.day-1 im) for 10 days. Controls (injected with vehicle) included 11 freely eating rats and 11 animals pair fed to match food intake of cortisone rats. Steroid treatment depressed body weight 30% compared with controls. Mass of diaphragm, gastrocnemius, and extensor digitorum longus showed significant atrophy (30%); heart and soleus were unaffected. Isometric contractile properties of costal diaphragm strips were studied in vitro using direct stimulation. The force-frequency relationship was markedly depressed by steroid treatment, both at low and high frequencies. However, force developed per unit cross-sectional area was similar among all three groups, as were twitch characteristics. When stimulated every minute, forces developed by control strips fell progressively, whereas the forces of cortisone-treated strips remained unchanged. When stimulated every 5 s, the fall in force was not different between groups. We conclude that cortisone weakened the diaphragm by decreasing muscle mass but made the diaphragm more resistant to one form of fatigue in vitro.

Animals↗