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Biomedical subjects

J A Simon

Publications and source records attributed to J A Simon.

126 records · Page 7Linked to original sources
PubMed1979

Comparative efficacy of pirprofen and aspirin in rheumatoid arthritis.

A six-month double-blind, randomized, parallel-design trial comparing pirprofen, a new nonsteroidal antiinflammatory drug, with aspirin in patients with rheumatoid arthritis is described. The dose of pirprofen, a phenylpropionic acid derivative, was 600 mg per day; the dose of aspirin was 3600 mg per day. Pirprofen was found to be as effective as aspirin in improving the modified articular index, swelling joint index, grip strength, walking time, and duration of morning stiffness. Fewer patients receiving pirprofen reported drug-related side effects than those receiving aspirin, however, the difference was not statistically significant (P less than 0.1). There was no significant difference between groups in the incidence of positive stool guaiac tests (three of 17, pirprofen; five of 18, aspirin). Pirprofen was found to be as safe and effective as aspirin in the management of patients with rheumatoid arthritis.

Adult↗
PubMedDate not supplied

Relationship of ascorbic acid to blood lead levels.

CONTEXT: Some animal studies suggest that orally administered ascorbic acid may chelate lead and decrease the risk of the toxic effects of lead. However, results from several small studies in humans have yielded inconclusive evidence of a beneficial effect of ascorbic acid on lead toxicity. OBJECTIVE: To examine the relationship between serum ascorbic acid levels and prevalence of elevated blood lead levels. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional analysis of a probability sample of the US population enrolled in the Third National Health and Nutrition Examination Survey, 1988-1994 (4213 youths aged 6-16 years and 15365 adults aged > or =17 years) without a history of lead poisoning. MAIN OUTCOME MEASURES: Elevated and log blood lead levels by serum ascorbic acid level. RESULTS: A total of 22 youths (0.5%) and 57 adults (0.4%) had elevated blood lead levels (defined as > or =0.72 micromol/L [15 microg/dL]) and > or =0.97 micromol/L [20 microg/dL], respectively). After controlling for the effects of age, race, sex, income level, and dietary energy, fat, calcium, iron, and zinc intake, youths in the highest serum ascorbic acid tertile had an 89% decreased prevalence of elevated blood lead levels compared with youths in the lowest serum ascorbic acid tertile (odds ratio, 0.11; 95% confidence interval, 0.04-0.35; P for trend = .002). Adults in the highest 2 serum ascorbic acid tertiles had a 65% to 68% decreased prevalence of elevated blood lead levels compared with adults in the lowest serum ascorbic acid tertile (P for trend = .03). As a continuous predictor, serum ascorbic acid level was independently associated with decreased log blood lead levels among adults (P<.001), but not among youths (P=.14). CONCLUSIONS: Our data suggest that high serum levels of ascorbic acid are independently associated with a decreased prevalence of elevated blood lead levels. If these associations are related causally, ascorbic acid intake may have public health implications for control of lead toxicity.

Adolescent↗
PubMedDate not supplied

The relation of smoking to waist-to-hip ratio and diabetes mellitus among elderly women.

BACKGROUND: Smoking is associated with lower body weight, but an increased risk of diabetes in some studies. Because smoking may increase waist-to-hip ratio (WHR), a risk factor for diabetes, we postulated that the relation between smoking and diabetes may be mediated in part by smoking-associated differences in body fat distribution. METHODS: We conducted a cross-sectional analysis of baseline data from 9,435 elderly nonblack women enrolled in the Study of Osteoporotic Fractures. Data were collected by Self-report and physical examination. Linear and logistic models were used to determine the relation of smoking to WHR and prevalence of self-reported diabetes. RESULTS: Current and past smokers had greater WHRs compared with never smokers. In multivariate models that adjusted for body mass index, the prevalence of diabetes was lower among smokers of < or = 10 cigarettes/day [odds ratio (OR) = 0.57, 95% confidence interval (CI) 0.31-1.03] and higher among smokers of > 10 cigarettes/day (OR = 1.38, 95% CI 0.99-1.92) compared with never smokers. The relation of smoking > 10 cigarettes/day to prevalence of diabetes was slightly attenuated after further adjustment for WHR. CONCLUSIONS: Smoking-associated differences in WHR may mediate, at least in part, the prevalence of diabetes among smokers of > 10 cigarettes/day. The decreased prevalence of diabetes that we observed among smokers of < or = 10 cigarettes/day was not explained by differences in obesity and requires confirmation.

Aged↗
PubMedDate not supplied

A hypersensitive site in hsp70 chromatin requires adjacent not internal DNA sequence.

Nuclease-hypersensitive sites in chromatin exist at the 5' side of many eukaryotic genes. To gain some understanding of the molecular basis of these hypersensitive sites, we have now examined the pair of sites upstream of the Drosophila hsp70 gene in a series of plasmids that contain deletions in the hypersensitive region and have been transformed into yeast cells. Hypersensitive sites 5' to a Drosophila hsp70 gene are preserved when this gene is introduced into yeast by transformation. We find that a yeast strain containing a plasmid in which the deletion extends through the first hypersensitive site still displays the normal pair of hypersensitive sites, so DNA sequences over which the first hypersensitive site is centred are not required for hypersensitivity at this position and the site can form over a foreign DNA sequence juxtaposed against this deletion end point. Deletions progressing further into the region bracketed by the pair of 5' hypersensitive sites eliminate the first hypersensitive site and alter the downstream site. We propose that the hypersensitive sites are generated through the binding of a protein that renders flanking sequences more accessible to nucleases, perhaps by preventing normal chromatin packaging.

Animals↗
PubMedDate not supplied

Sunburn and p53 in the onset of skin cancer.

Squamous cell carcinoma of the skin (SCC) can progress by stages: sun-damaged epidermis, with individual disordered keratinocytes; actinic keratosis (AK), spontaneously regressing keratinized patches having aberrant cell differentiation and proliferation; carcinoma in situ; SCC and metastasis. To understand how sunlight acts as a carcinogen, we determined the stage at which sunlight mutates the p53 tumour-suppressor gene and identified a function for p53 in skin. The p53 mutations induced by ultraviolet radiation and found in > 90% of human SCCs were present in AKs. Inactivating p53 in mouse skin reduced the appearance of sunburn cells, apoptotic keratinocytes generated by overexposure to ultraviolet. Skin thus appears to possess a p53-dependent 'guardian-of-the-tissue' response to DNA damage which aborts precancerous cells. If this response is reduced in a single cell by a prior p53 mutation, sunburn can select for clonal expansion of the p53-mutated cell into the AK. Sunlight can act twice: as tumour initiator and tumour promoter.

Animals↗
PubMedDate not supplied

Internal fixation of femoral neck fractures with posterior comminution: a biomechanical study.

OBJECTIVES: This study was performed to determine whether four cancellous lag screws provide significantly improved rigidity and fixation strength compared with three screws for fixation of displaced femoral neck fractures with posterior comminution. DESIGN: Biomechanical cadaver study. INTERVENTION: Eight pairs of mildly osteopenic femurs were selected, and each pair was fixed with three or four cancellous lag screws (randomly assigned) after the creation of a simulated femoral neck fracture with posterior comminution. A separate comparison with an unmatched group of six similar femurs with a simulated femoral neck fracture without posterior comminution and instrumented with three screws was performed to investigate the effect of posterior comminution. MAIN OUTCOME MEASUREMENT: The specimens were non-destructively tested to determine fixation rigidity in axial and anterior loading. Cyclic axial loading was then performed for 10,000 cycles; the femurs were retested for rigidity and finally were axially loaded until failure. RESULTS: The femurs with a posterior defect stabilized with three screws had significantly less resistance to axial and anterior displacement and sustained significantly lower axial loads to failure than those stabilized with four screws. The specimens instrumented with three screws without a posterior defect exhibited greater resistance to displacement in anterior loading and sustained greater axial loads to failure than those with a posterior defect stabilized with three screws. CONCLUSION: This study suggests that there are benefits to using four screws for fixation of femoral neck fractures with posterior comminution.

Biomechanical Phenomena↗
PubMedDate not supplied

Schuhli augmentation of plate and screw fixation for humeral shaft fractures: a laboratory study.

OBJECTIVES: Schuhli locking nuts provide a mechanism to lock 4.5-millimeter bone screws to a standard dynamic compression plate (DCP plate). It has been proposed that Schuhlis can provide increased fixation stability in areas of a proximal cortical defect or osteopenic bone and may keep screws from loosening and backing out from the plate. A biomechanical study was performed to investigate the effect of Schuhli augmentation of a ten-hole broad DCP plate for fixation of a simulated humeral shaft fracture versus standard DCP plate fixation. DESIGN: Biomechanical cadaver study. INTERVENTION: Six pairs of cadaveric humeri from elderly individuals were tested in offset axial loading, torsion, and four-point bending to obtain load versus deformation curves and baseline mechanical properties. Each pair of humeri was then instrumented with a ten-hole broad DCP plate on one side and a DCP plate augmented with Schuhlis at each screw hole on the contralateral side. All screws were placed in cortical bone. The constructs were retested in all three modalities. The humeri were then cycled in torsion for 1,000 cycles and retested in all three modalities. Each humerus was then loaded to failure in torsion to determine the ultimate load and rotational displacement. MAIN OUTCOME MEASUREMENTS: Resistance to displacement was determined from the load versus deformation curves in each testing modality before and after cycling; these data were normalized to the intact values determined prior to instrumentation. Paired Student's t tests were performed to determine statistically significant differences between the two modes of fixation. RESULTS: There were no significant differences in stability between the two fixation techniques in all three testing modalities both before and after cycling. However, the Schuhli augmented constructs sustained significantly greater loads and rotational deformations prior to failure. CONCLUSIONS: In this model of humeral shaft fractures in the elderly, the addition of Schuhlis did not significantly change the mechanical stability of plate and screw fixation. However, load and angular deformation at failure were significantly greater in the Schuhli augmented specimens.

Aged↗
PubMedDate not supplied

Fixation of periprosthetic femoral shaft fractures: a biomechanical comparison of two techniques.

OBJECTIVE: To determine which of two currently used techniques for the treatment of periprosthetic femoral shaft fractures provides the greater fixation rigidity and strength. DESIGN: A laboratory study using six matched pairs of femurs. METHODS: Embalmed femur prosthesis constructs had a simulated periprosthetic fracture created and were fixed with a plate with proximal cables and distal bicortical screws (Ogden concept) or two allograft struts and cables. Fixation stability was compared in various loading modalities before and after cycling. They were then tested to failure. OUTCOME MEASUREMENTS: Fixation rigidity was defined as the ratio of applied load to the amount of displacement at the fracture. RESULTS: In all loading modalities, the Ogden construct was more rigid than the allograft strut fixation. The Ogden construct required 1,295 newtons for failure and the allograft strut fixation required 950 newtons (p < 0.05). CONCLUSION: The Ogden construct provided a more rigid and stronger initial fixation of a periprosthetic fracture than did the allograft construct.

Arthroplasty, Replacement, Hip↗
PubMedDate not supplied

Unscheduled bleeding during initiation of continuous combined hormone replacement therapy: a direct comparison of two combinations of norethindrone acetate and ethinyl estradiol to medroxyprogesterone acetate and conjugated equine estrogens.

OBJECTIVE: To determine whether there are differences between continuous combined hormone replacement therapies on bleeding control. DESIGN: Nine hundred and forty-five postmenopausal women were randomized to one of seven double-blind treatment groups (placebo, 0.25 mg norethindrone acetate (NA)/5 microg ethinyl estradiol (EE), 1 mg NA/5 microg EE, 0.5 mg NA/10 microg EE, 1 mg NA/10 microg EE, 5 microg EE, and 10 micro EE) or unmasked 0.625 mg conjugated equine estrogens (CEE)/2.5 mg medroxyprogesterone acetate (MPA). Treatment was for 12 months; subjects kept daily diaries recording whether they had bleeding and/or spotting. RESULTS: The results focused on currently commercially available hormone replacement therapy products (femhrt [1 mg NA/5 microg EE] and Prempro [0.625 mg CEE/2.5 mg MPA]) as well as a high-dose NA/EE dose combination (1/10) over the first 6 months of use, the most critical period in establishing treatment adherence. At the end of month 6 there was a greater incidence of amenorrhea with both NA/EE dose combinations compared with CEE/MPA (p = 0.009 for 1 mg NA/5 microg EE and p = 0.006 for 1 mg NA/10 microg EE). Statistically significantly more women were amenorrheic at every month based on cumulative amenorrhea for 1 mg NA/5 microg (p < 0.05) compared with CEE/MPA; at months 3 and 6 more women were amenorrheic on 1 mg NA/10 microg EE compared with CEE/MPA using the cumulative amenorrhea parameter. CONCLUSIONS: The results indicate that statistically significantly more women attained amenorrhea based on various parameters when administered continuous combined NA/EE compared with CEE/MPA. The potential for long-term treatment compliance based on better bleeding control may optimize the opportunity to prevent osteoporosis as well as other associated health benefits.

Drug Combinations↗
PubMedDate not supplied

Infectious complications of intrauterine insemination: a case report and literature review.

Intrauterine insemination is commonly performed in the treatment of infertility. Infectious complications associated with intrauterine insemination are frequently cited, though rarely reported. A review of the literature yields only five reported cases of pelvic infections subsequent to intrauterine insemination (IUI), and only two of these show firm evidence of infection, with none presenting bacteriologic confirmation. We report a case of Escherichia coli septicemia subsequent to an IUI performed on a patient with a large adenomyoma. Of 147 patients treated with IUI at Georgetown University from November 1987 through March 1990, this was the only infectious complication. The incidence of infectious complications in our series is thus 0.0068 (6.8 per 1,000 women). A review of infectious complications in 38 reported series on intrauterine inseminations reveals five infections in 3,129 patients. With the addition of our series to the literature, the prevalence of infectious complications is 1.83 per 1,000 women undergoing IUI. The rates were not significantly altered by semen washing with antibiotics, or the administration of prophylactic antibiotics to the woman (P = .81). We conclude that (1) the infection rate following IUI is small, (2) many of the infections subsequent to insemination were not associated with intrauterine insemination, (3) most reported cases of infection fail to show evidence for the actual presence of infection, and (4) the prevalence is unaltered by the administration of prophylactic antibiotics or washing the semen sample with antibiotics.

Adult↗
PubMedDate not supplied

Income and racial patterns of dietary vitamin C intake among black and white girls.

The authors examined the influence of income and race on mean dietary vitamin C intake and the risk of dietary vitamin C intake at levels below the recommended dietary allowance (RDA). They performed a cross-sectional analysis of 2,032 black and white 9- and 10-year-old females, from a wide range of income groups, who participated in the National Heart, Lung, and Blood Institute Growth and Health Study. Mean intake of vitamin C, exclusive of vitamin supplements and determined by 3-day diet records, exceeded the RDA of 45 milligrams per day for that age group in all racial and income categories. The investigators found that annual household income was directly associated with mean dietary vitamin C intake (P < 0.0001) and that blacks had higher mean dietary vitamin C intakes than whites (P < 0.01). Among both blacks and whites, household income and risk of below-RDA vitamin C intake were inversely correlated, but this trend was statistically significant for blacks only (P < 0.05). Except for the lowest level income group (less than $10,000 per year), black girls from households with incomes less than $30,000 per year were at increased risk for below-RDA vitamin C intake (relative risk = 1.93 in the $10,000-$19,999 per year group and 1.63 in the $20,000-29,999 per year group, P < 0.05), compared with black girls in the highest income category. One-quarter of white girls overall and more than 30 percent of white girls in the lowest two income groups had below-RDA vitamin C intakes. If the findings are generalizable,they underscore the importance of public health programs to address the adequacy of dietary vitamin C intake among preadolescent black and white females.

Black or African American↗