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Biomedical subjects

R Marshall

Publications and source records attributed to R Marshall.

211 records · Page 12Linked to original sources
PubMedDate not supplied

The tilt test: effect of diabetes mellitus and antihypertensive medication on normal values.

The Tilt Test is a commonly used clinical tool for the assessment of volume depletion. Most of the data pertaining to the normal limits of the Tilt Test were determined by studying normal, healthy volunteers. Patients presenting with possible volume depletion, however, may have medical conditions (e.g., diabetes) or be taking medication (e.g., antihypertensives) that may affect the cardiovascular response to the Tilt Test. One hundred thirty-three euvolemic, asymptomatic outpatients (34 diabetics, 20 patients on beta blockers, 31 patients on diuretics, 28 patients on diuretics plus beta blockers, and 20 patients on clonidine hydrochloride) underwent Tilt testing. The readings obtained from each subgroup were compared to 33 sex- and age-matched controls who had no medical problems and were on no medications. No significant differences among the groups could be determined. We conclude that in otherwise euvolemic, asymptomatic patients, neither diabetes mellitus nor the specific antihypertensives studied interfere with the normal response to the Tilt Test.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Use of positioning to reduce the severity of neonatal narcotic withdrawal syndrome.

OBJECTIVE: This study tested the hypothesis that highly fretful, narcotic-withdrawing neonates experience less distress in a prone-lying position than comparable, supine-lying neonates. STUDY DESIGN: Equivalent numbers of randomly assigned, narcotic-withdrawing newborns were assigned to prone-lying (n = 25) or supine-lying (n = 23) conditions. Subjects in the two groups were similar with regard to gestational age, birth weight, and clinical presentation. Peak and mean withdrawal severity, as measured by Neonatal Abstinence Scoring System (NASS) scores and daily caloric intake, were compared between supine and prone groups by Wilcoxon's two-sample test. RESULTS: The prone-lying neonates had lower peak NASS scores (p < 0.0001), lower mean NASS scores (p < 0.0001), and lower caloric intake (p < 0.001) than supine-lying, narcotic-withdrawing newborns. CONCLUSION: The fretfulness associated with neonatal withdrawal and other stressful conditions can be moderated by laying the affected infant prone. The pronate quieting response is a significant, endogenous source of neonatal pacification.

Energy Intake↗
PubMedDate not supplied

Use of a 24-hour recall diary to assess exposure to environmental tobacco smoke.

Methods to assess exposure to environmental tobacco smoke need to be valid and relatively easy to use. We therefore explored the use of a 24-h environmental tobacco smoke exposure-recall diary by comparing data from the 24-h diary with questionnaire responses and levels of salivary cotinine--a biochemical marker of environmental tobacco smoke exposure. A total of 875 nonsmokers at five Rhode Island worksites participated in the study. Twenty-five percent of the participants lived with smokers, and 96% had regular exposure to environmental tobacco smoke at work. Individuals who lived with smokers reported more exposures in the 24-h diary, both outside of work and during work hours, compared with those who had no smokers in their household. The correlation between saliva cotinine concentrations and the exposures recorded in the diary was weak (r = .10). Brief instruments for assessment of environmental tobacco smoke should be viewed cautiously, and use of this 24-h recall diary is not recommended.

Adult↗
PubMedDate not supplied

Psychostimulant effects on neuropsychological, intellectual, and achievement measures for children and adolescents with Attention Deficit Hyperactivity Disorder.

This study compared the performance of medicated (n=57) and non-medicated (n=20) subjects with Attention Deficit Hyperactivity Disorder (ADHD) on neuropsychological, intellectual, and achievement measures. The Wechsler Intelligence Scale for Children (Revised or 3rd Edition), appropriate Halstead Reitan Neuropsychological Test Battery, and individual achievement tests were administered to subjects between the ages of 9 and 16 years (M=12.8) Initially, 26 subtest scores were analyzed using multivariate profile analysis. The two groups were found to be parallel (i e, similar in pattern of performance) and coincident (i.e., similar in level of performance). This suggests that the subjects in the two groups displayed a similar pattern of performance on these neuropsychological, intellectual, and achievement measures. The results are discussed in relation to previous research, current etiological models, and the assessment and treatment of ADHD.

Journal Article↗
PubMedDate not supplied

Ciprofloxacin: in vitro, experimental, and clinical evaluation.

Ciprofloxacin at a concentration of 2 micrograms/mL inhibited the growth of approximately 90% of 584 strains of aerobic bacteria isolated from cultures of blood drawn from septicemic patients. An increase in the inoculum size did not result in an increased MIC, but serial passages through media containing ciprofloxacin at sub-MIC levels increased the MIC for Escherichia coli, Klebsiella pneumoniae, and Proteus vulgaris. In experimental subcutaneous abscesses in the mouse model, ciprofloxacin was more active than cefotaxime against a mixed infection induced with E. coli and Bacteroides fragilis. Against mixed E. coli and Staphylococcus aureus infection, no significant differences were noted between the two drugs. In a double-blind, prospective, randomized clinical study, perorally administered ciprofloxacin was compared with intravenously administered cefotaxime in the treatment of skin and soft-tissue infections severe enough to require hospitalization. In 70 patients treated, the therapeutic efficacy of peroral ciprofloxacin was comparable to that of intravenous cefotaxime, with two differences: S. aureus infections responded less favorably to oral ciprofloxacin (62%) than to intravenous cefotaxime (90%), and aerobic gram-negative bacillary infections responded more favorably to ciprofloxacin (92%) than to cefotaxime (64%).

Abscess↗
PubMedDate not supplied

Clinical and pharmacologic management of chronic heart failure associated with left ventricular systolic dysfunction.

Despite many recent advances, heart failure continues to be a major cause of morbidity and mortality in the United States. Once a patient is identified and evaluated as having heart failure, nonpharmacologic therapies such as a dietary restrictions, lifestyle changes, exercise strategies, and patient education are initiated as well as pharmacologic therapy. Angiotensin-converting-enzyme inhibitors, diuretics, and digoxin all are considered traditional therapy in the management of chronic heart failure associated with left ventricular systolic dysfunction. The role of newer therapies such as beta-blockers and angiotensin II receptor antagonists in the treatment of heart failure is in the process of being defined. Furthermore, new data is appearing concerning calcium channel blockers, spironolactone, and combinations of the various agents. Appropriate use of the traditional agents accompanied by a through understanding of the newer therapies and their roles is essential to the continued reduction of the morbidity and mortality associated with heart failure.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

In vitro screening of therapeutic agents against Cryptosporidium: hyperimmune cow colostrum is highly inhibitory.

An in vitro model of Cryptosporidium parvum infection was developed utilizing an adherent human intestinal epithelial cell line HT29.74. The efficacy of potential immunologic therapy in the form of Cryptosporidium-specific hyperimmune bovine colostrum was evaluated for the ability to inhibit in vitro infection. Oocysts were purified from stool of chronically infected AIDS patients. Hyperimmune colostrum obtained from cows immunized with Cryptosporidium and nonimmune conventional colostrum were evaluated. oocysts (10(5)-10(6)) were pre-incubated with either hyperimmune colostrum, conventional colostrum, or saline as control, for 15 min at room temperature than applied to a 70% confluent monolayer of HT29.74 cells. Cryptosporidium schizonts were identified and counted per 1,000 HT29.74 cells under oil immersion after 24 h. In the presence of hyperimmune colostrum, parasite infection was inhibited by 82% (p less than 0.001), and the presence of conventional colostrum, infection was inhibited by 67% (p less than 0.001). Treatment with the soluble fraction of hyperimmune colostrum resulted in 69% inhibition (p less than 0.001) compared to the soluble fraction of conventional colostrum which resulted in only 17% inhibition (p = NS). In vitro Cryptosporidium parvum infection of the differentiated human enterocyte cell line HT29.74 is a viable method for screening immunologic therapies. Hyperimmune bovine colostrum was highly inhibitory of Cryptosporidium infection in vitro and its soluble fraction remained significantly inhibitory while the soluble fraction of conventional colostrum did not.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Ultrastructural study of asexual development of Cryptosporidium parvum in a human intestinal cell line.

The lack of a well-defined in vitro model of Cryptosporidium infection has severely hampered research on the biology of parasitic invasion of the host cell and on intracellular development of the parasite. In vitro infection of the differentiated human enterocyte cell line HT29.74 was studied by electron microscopy to detect changes in parasite and host cell morphology. Cryptosporidium oocysts obtained from AIDS patients were applied to a monolayer of cloned differentiated HT29.74 cells. Parasites and infected cells were evaluated by transmission electron microscopy at 20 min, 1 h, 6 h, 24 h and 7 days. Sporozoite invagination within the epithelial cell microvilli and subsequent penetration was evident at 1 h. At 6 h, the development of a dense band and feeder layer was visible. Development of the trophozoite into a schizont occurred over 24 h. Micronemes and dense granules were clearly visible within sporozoites and merozoites. Organization of vacuoles within the cytoplasm of the host cell was evident below the dense band. A sexual Cryptosporidium development in vitro was morphologically no different from initial development in vivo. In vitro infection of HT29.74 cells provides an excellent model to study parasite-host cell interaction and asexual parasite development.

Animals↗