Search PubMed⌕ Search

Biomedical subjects

S Baker

Publications and source records attributed to S Baker.

At least 145 records · Page 8Linked to original sources
PubMed1991

Chronic fatigue syndrome: I. Epstein-Barr virus immune response and molecular epidemiology.

Patients with chronic fatigue syndrome were compared to healthy seropositive control subjects in an open study and a case-control study analyzing spontaneous transformation rates of peripheral blood lymphocytes, EBV viral genome characteristics as determined by DNA restriction fragment polymorphisms, and antibody production by Western blot analysis. Thirty percent of patients versus 8% of control subjects underwent spontaneous transformation in the two studies. Viral genome patterns were overall similar to one another, with polymorphisms frequently present in BamHI B', K, H, and Y fragments. Only one line was found with the EBNA-2B genotype. Nineteen lines were found to contain viral DNA in the linear form suggesting active lytic replication. Western blot studies suggested that ill subjects made antibodies to lytic proteins more frequently than did healthy control subjects. Lack of control of EBV outgrowth in vitro is correlated with antibody evidence of active infection in vivo in some patients with chronic fatigue syndrome.

Antibodies, Viral↗
PubMed1991

Androgen effects on cognition: congenital adrenal hyperplasia.

Cognitive studies of congenital adrenal hyperplasia (CAH) patients have revealed (1) the presence of an IQ advantage in patients, siblings and parents due to socioeconomic status, genetic, hormonal, or other factors; (2) an IQ disadvantage in salt wasters compared with simple virilizers, probably due to early brain damage secondary to salt-wasting crisis; (3) a possibly increased incidence of learning disabilities, particularly in female patients and particularly for calculation abilities, due to disease-related early androgen exposure; and (4) a possible post-pubertal spatial advantage in CAH women, also due to early androgen exposure.

Adrenal Hyperplasia, Congenital↗
PubMed1991

Effect of meal on the physiological and physicochemical actions of potassium citrate.

The effect of meals on the physiological and physicochemical actions of potassium citrate was examined in 8 patients with nephrolithiasis maintained on a constant metabolic dietary regimen. Potassium citrate (20 mEq. 3 times per day), whether given with food or on an empty stomach, significantly increased urinary pH, citrate and potassium, and decreased urinary calcium and ammonium. Moreover, potassium citrate decreased urinary saturation of calcium oxalate and uric acid, although it slightly increased that of brushite. However, there was no significant difference in these measures when the drug was given with meals from the time when it was given on an empty stomach. Thus, the effect of potassium citrate on urinary risk factors is unaffected by food.

Adult↗
PubMed1991

Learning disabilities in children with congenital adrenal hyperplasia.

Early exposure to androgens may be a cause of the higher incidence of learning disabilities among males. To test this hypothesis, we determined the frequency of learning disabilities, as measured by extent of Wechsler Verbal-Performance IQ discrepancy, among female patients with congenital adrenal hyperplasia, who are exposed in utero to excess androgens for their sex. A significantly larger Verbal-Performance IQ discrepancy (10.1 vs 7.7) was found for the 18 female patients than for 27 unaffected female siblings (P = .045, one-tailed). The Verbal-Performance IQ discrepancy of the females with congenital adrenal hyperplasia is in the male range (10.4 to 13.4), similar to males with congenital adrenal hyperplasia (n = 20) and unaffected male siblings (n = 31). In addition to the sex effect, there is an effect of the type of congenital adrenal hyperplasia on the frequency of learning disabilities. Simple virilizers are more likely to be learning disabled than salt-wasters (P = .04, one-tailed). However, salt-waster patients have a lower IQ (104 vs 117) than simple virilizer patients (P = .005, one-tailed). Presumably, this is because some salt-waster patients suffer brain injury from episodes of hypotension and hyponatremia. The diffuse insult to the central nervous system may overide the androgen effect and result in a general cognitive impairment. Because of this confounding effect on IQ in the salt-waster form of congenital adrenal hyperplasia, the simple virilizer female versus unaffected female siblings reprsents the best test of the hypothesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Comparison of iohexol with barium in gastrointestinal studies of infants and children.

This study evaluates iohexol as a contrast agent in the gastrointestinal tract in children. In the first part of the study, iohexol in concentrations of 180 and 300 mg l/ml was compared in double-blind manner with barium. Sixty-four patients were studied. No significant difference in changes of blood pressure and pulse rate was found between the three groups of patients studied. Diarrhea was significantly more common in the children receiving iohexol than in children receiving barium. The diarrhea was not due to previously identified high-risk factors in the children, nor was it due to concurrent medication. When image quality was assessed in each anatomic region of the gastrointestinal tract, fewer nondiagnostic ratings occurred with barium than with iohexol. With barium, fewer ratings of poor mucosal coating and slightly fewer ratings of suboptimal contrast density occurred. The second part of the study was an open evaluation of iohexol 180 mg l/ml in 18 patients in whom barium was clinically contraindicated. Three of 53 assessments were nondiagnostic. Mucosal coating was poor in 6%, and contrast density was suboptimal in 8% of patients. The results of this study indicate that barium is the preferred contrast agent for routine evaluation of the gastrointestinal tract in children. Good-quality images can be obtained, however, with iohexol in concentrations of 180 or 300 mg l/ml, and iohexol is an excellent contrast agent for evaluation of the gastrointestinal tract in those patients in whom barium is relatively or absolutely contraindicated.

Adolescent↗
PubMed1991

Nosocomial pneumonia in the critically ill: product of aspiration or translocation?

OBJECTIVE: To examine the possibility that nosocomial pneumonias might be caused by the translocation of enteric bacteria and their toxins. DESIGN: Prospectively collected previous database was examined by logistic regression analysis. SETTING: University medical center. PATIENTS: Sixty-two ICU patients. MEASUREMENTS AND MAIN RESULTS: The best stand-alone predictors for nosocomial pneumonia were bleeding from stress ulceration (p less than .001), the severity of illness present (p less than .001), and intramucosal acidosis in the stomach (p = .023), a metabolic indication of mucosal ischemia. Mechanical ventilation (p = .038) and the administration of antacids/cimetidine (p = .054) were also of stand-alone predictive value, but did not significantly improve the best predictive model for nosocomial pneumonia derived from the severity of illness present and the intramucosal pH in the stomach. CONCLUSIONS: The findings are consistent with the hypothesis that ischemic mucosal injury and its associated translocation of enteric bacteria and toxins might be more important in the pathogenesis of nosocomial pneumonia in the critically ill than the aspiration of contaminated nasopharyngeal secretions.

Cross Infection↗
PubMed1990

[Screening for colorectal neoplasms].

We screened groups at high risk for colorectal neoplasms, determining the efficacy of the leukocyte adherence inhibition test (LAI) for early detection, in comparison with that of the fecal occult blood (Hemoccult) test and sigmoidoscopy or colonoscopy. Those screened included 549 first-degree relatives of patients with colorectal cancer, 190 patients with a past history of colorectal adenoma or carcinoma and 67 with a past history of breast or gynecological cancer or inflammatory bowel disease. 146 normal volunteers served as controls. In 782 of those fully screened during a 3-year period, 121 had adenomas (15.5%) and 5 had invasive cancer (0.6%). The LAI test was positive in 21% of those at high risk and in 7.5% of the controls. The hemoccult test was positive in only 4.8%, but in 1/3 of them neoplasms were found. This predictive value of 33% compares with only 16% for the LAI test. That most of the neoplasms found were adenomas and not invasive cancer may be due to the relative youth of most of those screened. We conclude that the groups studied were indeed at high risk. The LAI test is not sensitive enough to identify benign adenomas but might serve as another risk-market for colorectal neoplasms. Long-term follow-up of those at high-risk with positive LAI tests may prove that we have identified a subgroup truly at risk.

Adenoma↗
PubMed1990

Causes of pediatric eye injuries. A population-based study.

Eye injuries are an important cause of ocular morbidity in children. We conducted a population-based study of eye injuries requiring hospital admission for children younger than 16 years in the state of Maryland during the 1982 calendar year. The population-based estimate of the incidence of ocular trauma in Maryland children was 15.2 per 100,000 per year (95% confidence interval, 12.8 to 17.7). Male patients outnumbered female patients as victims of eye injuries by a ratio of approximately 4:1; eye injuries in 11- to 15-year-old children occurred at more than twice the rate than for younger children. The most common cause of pediatric ocular trauma was accidental blows and falls (37%). Sports and recreational activities accounted for 27% of all eye injuries, 39% of all nonpenetrating injuries, and 40% of all injuries in 11- to 15-year-old children. A comparison of the causes of eye injuries at statewide specialty trauma centers and community-based hospitals indicated that sports-related injuries were treated at general hospitals more than 10 times more frequently than at the trauma centers. Other important causes of eye injuries were burns (9%), car crashes (11%), and nonpowder firearm accidents (4%). We conclude that the majority of pediatric eye injuries are preventable, and that the implementation of well-established safety precautions would greatly reduce this source of visual disability in our nation's children.

Accidental Falls↗
PubMed1990

The effects of precocious adrenarche on cognition and hemispheric specialization.

Cognitive skills were assessed in 13 females with a history of precocious adrenarche (PA). They were of average intelligence. In terms of lateralized cognitive skills, PA had no effect on verbal fluency. The spatial abilities of females with a history of PA, who had reached gonarche (were fully pubertal), were inferior to those of females tested in the midst of PA and to population controls. The physiologic/hormonal changes associated with normal adrenarche may curtail further specialization of the right hemisphere, resulting in a relative spatial deficit among females in general, who as a group reach adrenarche earlier than males. This spatial performance deficit is exaggerated in females with PA.

Adolescent↗
PubMed1990

Split calvarial grafts in maxillofacial reconstruction.

Experience with thirty-seven patients demonstrating the versatility of the split calvarial graft in facial reconstruction is presented. A total of sixty grafts have been used with no evidence of significant clinical reabsorption, infection, or extrusion; advantages and limitations are discussed. We conclude that the split calvarium represents a readily available and reliable source of membraneous bone for grafting maxillofacial defects with minimal limitations and low morbidity.

Adult↗
PubMed1990

Weight training decreases vertebral bone density in premenopausal women: a prospective study.

The effect of exercise on bone mass is unclear. To determine the skeletal effect of weight-bearing exercise in premenopausal women, we prospectively evaluated the effects of a weight-training program on lumbar spine bone mass in 10 women (mean +/- SEM, 36.2 +/- 1.3 yr) and compared the results with those in 7 sedentary women (40.4 +/- 1.6 yr). None of the women had previously participated in a weight-training program, and all ingested a 500-mg calcium supplement each day throughout the study. Axial loading and balance of large muscle groups were emphasized. Individual strength increased by 57 +/- 8% over 9 months. Despite the increase in muscle strength, lumbar spine bone density in the exercising women decreased by 2.90% at 4.5 months and 3.96% at 9 months (P = 0.01). In contrast, there was no change in lumbar density in the controls over the 9-month period. We conclude that short term weight training at this frequency and intensity decreases vertebral bone mass in premenopausal women.

Adult↗
PubMed1990

A descriptive survey of black nursing faculty.

This descriptive study looks at the cohort of Black nursing faculty members teaching in baccalaureate and higher degree programs from a national perspective. The researchers were interested in how Black faculty members were faring in the halls of academe.

Adult↗
PubMed1989

Antibody-dependent cellular cytotoxicity mediated by lung macrophages: a comparison of two target cells.

Mononuclear cell-mediated cytotoxicity may be an important cellular immune function in host lung defense. Prior investigators have shown that lung macrophages participate in cell cytotoxicity which is antibody-dependent (ADCC). We tested the hypothesis that alveolar macrophages share some cell surface receptors for the Fc portion of IgG, i.e., Fc receptors, similar to those found on circulating monocytes in order to function in ADCC. Hence, ADCC mediated by autologous human blood monocytes and lung macrophages was studied by measuring the release of chromium-51 from prelabeled target erythrocytes coated with IgG. Alveolar macrophages were obtained from healthy adult subjects by bronchoalveolar lavage and tested against two different erythrocyte target cells to measure ADCC activity. Our results show significant activity by alveolar macrophages demonstrated against chicken erythrocytes at a target to effector cell ratio of 2:1 or 10:1 and with an antibody concentration of 1:100 or 1:400 (volume per volume, p less than 0.05, Student's test). However, when a peripheral blood monocyte specific target cell (human type B erythrocyte) was utilized, alveolar macrophages were not as capable of significant ADCC activity against these monocyte-specific target cells. The inability of lung macrophages to function in ADCC against other target cells (i.e., human type B erythrocytes) unlike the peripheral blood monocytes suggests that some Fc receptors are not shared. In other words, these different cell types share IgG receptors but differences in activity may be due to some changes in the Fc portions of IgG due to cellular differentiation. The use of these target cells may potentially be useful in functionally discriminating between two types of adherent autologous mononuclear cells (lung macrophages vs. blood monocytes).

Adult↗