PubMed Health⌕ Search

Biomedical subjects

S Whitaker

Publications and source records attributed to S Whitaker.

At least 37 records · Page 2Linked to original sources
PubMed1987

Determination of cell membrane permeability in concentrated cell ensembles.

The method of volume averaging is used to analyze the process of diffusion in concentrated cell ensembles in which significant resistance to mass transfer is caused by the cellular membrane. A general closure scheme is given that allows for direct theoretical prediction of effective diffusivities for any cellular geometry. Numerical results are presented for the classical parallelepiped arrangement used to model cellular systems, and these results are used in conjunction with experimental studies of concentrated cell ensembles to determine membrane permeabilities for solute diffusion in several cellular systems. Membrane permeabilities are compared with predictions from other models of diffusion in cellular systems.

Animals↗
PubMed1982

The transiency of oropharyngeal colonization with gram-negative bacilli in residents of a skilled nursing facility.

To determine the duration and persistence of gram-negative bacillary (GNB) oropharyngeal colonization over a specified period and the risk of subsequent GNB pneumonia developing in nursing home patients, we prospectively cultured for 31 weeks the oropharynges of patients in a skilled nursing facility. Over a 31-week period, an average of 13.8 percent of the patients showed colonization (weekly prevalence rates ranged from 0 to 29 percent). No patient had pneumonia during the study period. We concluded that the presence of GNB in the oropharynx of our patients is transient, continually changing over an extended period, and that GNB colonization as a transient occurrence is not directly associated with an increased risk of GNB pneumonia. Our data also emphasize the limitations of previously described single-culture survey studies in predicting the importance of GNB oropharyngeal colonization.

Adult↗
PubMed1980

An outbreak of acinetobacter infection associated with the use of a ventilator spirometer.

Although respiratory therapy equipment is a well-known source of nosocomial infection, ventilator spirometers have not been previously implicated. We report 17 Acinetobacter calcoaceticus variety anitratus infections traced to contaminated spirometers. Isolates from infected patients were recovered from urine, sputum, wounds, and blood. A review of attack rates for Acinetobacter was prompted by a dramatic increase in blood culture isolates. Prospective surveillance of intensive care environment, personnel, and patients established that Bennett MA-1 spirometers constituted the major reservoir of infecting organisms. Despite daily sterilization, 30% of spirometers in use were found to be contaminated. The hands of 12% of intensive care nurses and 10% of respiratory therapists cultured were found to be colonized. In addition to the infected patients, 28 other patients on spirometer-equipped ventilators were judged to be colonized by Acinetobacter following examination of sputa and/or mouthwashings. Following discontinuation of spirometer use and following increased emphasis on proper handwashing, the incidence of Acinetobacter infections dropped dramatically. Antibiosis in the intensive care environment and a deterioration in aseptic awareness serve to make Acinetobacter an environmental opportunist of increasing importance.

Acinetobacter Infections↗
PubMed1980

Idiopathic sudden hearing loss.

Idiopathic sudden hearing loss is an otologic emergency with an obscure cause. It is the acute onset of hearing loss of 30 cB in three contiguous frequencies, which may occur instantaneously or progressively over several days. Suspect etiologies include viral infections, cochlear artery occlusion, rupture of the intracochlear membranes, and biochemical alterations in the metabolism maintaining the endocochlear membrane potentials. Histopathology of the temporal bone most commonly reveals atrophy of the organ of Corti and striae vascularis. Treatments proposed include close observation for spontaneous recovery, steroid theray, and combination regimens of vasodilators, steroids, diuretics, and intravenous iodinated radiocontrast material. Prognosis and recovery are related to the audiometric pattern of the hearing loss and associated symptoms. The absence of vertigo at th clinical onset and low tone hearing loss are associated with better hearing recovery.

Adult↗
PubMed1979

Predictive value of serial carcinoembryonic antigen levels in long-term follow-up of ovarian cancer.

The predictive value of serial levels of carcinoembryonic antigen (CEA) in tumor monitoring was examined in 213 patients with ovarian cancer; each patient had been followed-up at monthly intervals for at least 12 months. CEA was not detectable throughout the period of observation in 35% of the patients. In general. patterns showing a disappearance of CEA or persistently low levels were associated with a good prognosis, whereas those showing a reappearance or highly elevated and rising levels were associated with a poor prognosis. A transient reappearance of CEA was observed in 10 patients; this did not appear to be associated with tumor recurrence or progression. "False positive" results were obtained in 6 patients in whom no tumor has been clinically detectable to date. "False negative" results were obtained in 4 patients with obvious tumor progression. In terms of a good or poor prognosis, the use of CEA levels was highly accurate in patients with minimal or no residual disease (97% and 89%, respectively); the rate fell to 62% in patients with extensive disease. As the clinical significance and limitations become better known, serial CEA levels should contribute substantially to the monitoring of patients with ovarian cancer.

Carcinoembryonic Antigen↗
PubMed1979

Effect of blood dilution on recovery of organisms from clinical blood cultures in medium containing sodium polyanethol sulfonate.

This clinical study was designed to evaluate the standard laboratory protocol that requires blood specimens be diluted with greater than or equal to 10 volumes of media. Blood was collected from hospitalized patients, and 1 ml was inoculated into each of three vials containing 2.3, 7.3, and 24 ml of BACTEC 6B aerobic medium resulting in dilutions of 1:4, 1:10, and 1:30, respectively. The three test vials were treated identically, and the study was carried out at four hospitals. Of the 2,550 sets of vials inoculated, 174 were positive with clinically significant isolates from 105 patients. There was no difference in the number of positive cultures recovered by 24 h (67%) or 48 h (90%) from any dilution. These percentages agreed with other reports from BACTEC users. The number of positive vials (139, 144, 147, respectively) at each dilution was not significantly different, indicating that all three dilutions showed equal recovery of pathogenic microorganisms. Despite this overall equality, two patients, one on antibiotic therapy, were found to have correlated cultures which failed to grow at the 1:4 dilution. This finding implies that a 1:4 dilution of blood cannot be recommended unequivocably despite the higher overall recovery rate of positive cultures.

Bacteria↗
PubMedDate not supplied

The faculty advisor role: an imperative for student retention.

The decline in applicants to schools of nursing emphasizes the importance of retaining those students who do enroll. The authors review factors affecting student attrition and retention in academic settings. They then present an ideal model for enhancing student retention through effective, individualized, and consistent student advising.

Education, Nursing, Baccalaureate↗