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Biomedical subjects

J Freeman

Publications and source records attributed to J Freeman.

At least 73 records · Page 4Linked to original sources
PubMed1999

Comparison of low-dose epidural with combined spinal-epidural analgesia for labour.

We have performed a randomized comparison of two low-dose epidural regimens for analgesia in labour, differing only in the manner in which initial analgesia was established. In the epidural (EPI) group, 484 women received a loading dose of 20 ml of 0.1% bupivacaine with fentanyl 2 micrograms ml-1. In the combined spinal-epidural (CSE) group, 524 women received a spinal injection of plain bupivacaine 2.5 mg with fentanyl 25 micrograms. In both groups, these initial doses were followed by 0.1% bupivacaine with fentanyl 2 micrograms ml-1 infused at a rate of 12 ml h-1, with 20-ml top-ups for breakthrough pain. The groups were compared for midwife assessment of analgesic efficacy, delivery mode, patient assessments of first stage analgesia, second stage analgesia, overall analgesia, motor block and complications. Midwives, who were not blinded to the treatment groups, assessed 61.6% of CSE as providing 'excellent' analgesia compared with 56.4% of epidurals (P = 0.02). Patients assessed overall analgesia as 'excellent' in 74.8% of CSE compared with 71.7% of epidurals (P = 0.14). Other comparisons between groups revealed no differences. These findings may have been affected by an uneven distribution of multiparous women between the groups (25% in the EPI group and 34.2% in the CSE group; P = 0.002). However, subgroup analysis of primiparous and multiparous women did not alter the results.

Adolescent↗
PubMed1999

The implementation and maintenance of the Ketogenic Diet in children.

The Ketogenic Diet is an effective treatment for epilepsy in children. At Johns Hopkins Hospital more than 400 children have been placed on the Ketogenic Diet. The implementation and maintenance of this treatment require significant collaboration between the family and Epilepsy Team. During initiation of the diet, in the hospital, parents attend classes on the history and mechanism of the diet, preparation of meals, psychological issues, complications and the management of childhood illnesses on the ketogenic diet. Many factors are considered in calculating a ketogenic formula. Age, weight, height and activity level are the obvious factors. However, secondary medical diagnoses, medications, neurological deficits, feeding issues and psychological issues are additional factors that affect the formulation of an optimal ketogenic prescription. Once this prescription has been formulated and implemented, many patients require fine-tuning of their ketogenic diets to get the best antiepileptic results while promoting growth. We believe that our success in sustaining this treatment is related to our fine-tuning and management practices.

Adolescent↗
PubMed1999

Evolutionary constraint networks in ligand-binding domains: an information-theoretic approach.

Ligand-binding sites in homologous protein domains can diverge greatly during evolution. This poses a particularly interesting problem in those cases where the ligand-binding site is situated in, or close to, the domain core, or where ligand-docking induces dramatic conformational changes. These features are present in many receptors and enzymes; the hormone-binding domain of the nuclear receptors for steroids and retinoids, for example, exhibits both characteristics. It is therefore of great interest to determine how binding sites for diverse ligands evolve in core regions of structurally dynamic domains. Are evolutionary changes locally restricted to the ligand-binding site, or are they distributed throughout the domain? We describe here an information-theoretic approach for the study of covariation between ligand-contacting residues and compensatory mutations that preserve the structural integrity and the conformational dynamics of ligand-binding domains. We apply this method to the analysis of the nuclear receptor ligand-binding domain and show that the ligand-contacting residues in the hormone-binding pocket are evolutionarily linked to an extensive network of covarying positions.

Amino Acid Sequence↗
PubMed1999

The haemodynamic effects of propofol in combination with ephedrine in elderly patients (ASA groups 3 and 4).

The marked vasodilator and negative inotropic effects of propofol are disadvantages in frail elderly patients. We investigated the safety and efficacy of adding different doses of ephedrine to propofol in order to obtund the hypotensive response. The haemodynamic effects of adding 15, 20 or 25 mg of ephedrine to 200 mg of propofol were compared to control in 40 ASA 3/4 patients over 60 years presenting for genito-urinary surgery. The addition of ephedrine to propofol appears to be an effective method of obtunding the hypotensive response to propofol at all doses used in this study. However, marked tachycardia associated with the use of ephedrine in combination with propofol occurred in the majority of patients, occasionally reaching high levels in individual patients. Due to the risk of this tachycardia inducing myocardial ischemia, we would not recommend the use in elderly patients of any of the ephedrine/propofol/mixtures studied.

Adrenergic Agents↗
PubMed1999

Using the Short Form-36 with multiple sclerosis patients in five countries: a cross-cultural comparison.

Questionnaires measuring health-related quality of life are increasingly used in international studies of medical effectiveness. It is important to know if data from these instruments are comparable across countries. We initiated a collaboration among five research groups--from the USA, The Netherlands, Belgium, France, and the UK--in the field of health-related quality of life in multiple sclerosis. All groups used the 36-item Short Form Health Survey. The goal of our study was to make a cross-cultural comparison. In the five countries under study the sample size varied from 50 to 134 patients with multiple sclerosis. The survey was completed by a total of 457 patients, who were heterogeneous in relation to age, duration of illness, severity and type of multiple sclerosis. There appeared to be major differences among the samples in scores on each of the eight scales. These findings may be influenced by differences in method of recruitment, demographic and disease-related characteristics, administration, and cultural factors. After having performed a number of analyses, it appeared that the differences were mainly attributable to sampling effects; however, cultural influences could not be excluded.

Adult↗
PubMed1999

Effect of chemotherapy on malaria transmission among Yanomami Amerindians: simulated consequences of placebo treatment.

To determine whether chemotherapy effectively reduces Plasmodium falciparum malaria transmission in isolated human populations, we followed two abrupt sequential outbreaks of malaria infection among Yanomami Amerindians and modeled the effect of chemotherapy and the consequences if no drug was available. A Macdonald-type mathematical model demonstrated that both outbreaks comprised a single epidemic event linked by an invisible outbreak in vector mosquitoes. The basic reproductive number, R0, from fitted values based on the treated epidemic was 2 during the initial phase of the epidemic, and waned as vector density decreased with the onset of the dry season. In the observed epidemic, 60 (45%) of 132 village residents were affected, and the treated outbreak ended after two months. Although the initial chemotherapy regimen was only marginally effective, the duration of human infectivity was reduced from an expected nine months to two weeks. In the absence of this intervention, the initial R0 value would have been 40, more than 60% of the population would have been infected, and more than 30% would have remained parasitemic until the next rainy season (about six months later). Another outbreak would then have ensued, and malaria probably would have remained endemic in this village. Our simulated placebo treatment permits us to conclude that even partially effective chemotherapeutic interventions, such as those in our study, interrupt serial transmission of P. falciparum among isolated human populations that are exposed to infection seasonally.

Animals↗
PubMed1998

Synthesis and evaluation of compounds that facilitate the gastrointestinal absorption of heparin.

A family of novel compounds (delivery agents) that promote the gastrointestinal absorption of USP heparin in rats and primates has been discovered. The delivery agents in combination with heparin were administered either orally or intracolonically in an aqueous propylene glycol solution and caused dramatic increases in both plasma heparin concentrations (anti-Factor Xa) and clotting times (APTT). Using one of the most effective delivery agents in this series, an estimated relative bioavailability of 8% can be achieved following oral administration to cynomolgus monkeys. To establish a correlation between the in vivo data and an in vitro parameter, immobilized artificial membrane (IAM) chromatography was performed. Log relative k' values were correlated to the efficiency of oral heparin delivery.

Amino Acids↗
PubMed1998

Doctor talk and diabetes: towards an analysis of the clinical construction of chronic illness.

During the last two decades the illness narrative has emerged as a popular North American literary form. Through poignant stories, well-educated patients have recounted their struggle with disabling diseases as well as with the hospitals and health care bureaucracies from whom they seek service. However, much less has been written about the doctor's narrative construction of chronic diseases either in the process of learning medicine or through diagnosing, treating and counseling chronically ill patients. Indeed, following Kleinman's lead, the physician's narrative has been narrowly viewed as a discourse on the verifiable manifestations of pathophysiology. Drawing on contemporary theories of storytelling--including the conception of narrative as conversational interaction--the present paper argues that doctor narratives are equally complex if quite different than patient stories. Indeed, through an analysis of doctor talk centering on diabetes mellitus collected in several distinct venues--case presentations, narrative interviews and medical consultations--it is argued that physician stories not only employ very evocative tropes, but that these stories combine didactic, rhetorical and soterological elements in the telling. The research was conducted at two, urban family practice training sites in Chicago.

Attitude of Health Personnel↗
PubMed1998

Prevalence of antimicrobial resistance among respiratory tract isolates of Streptococcus pneumoniae in North America: 1997 results from the SENTRY antimicrobial surveillance program.

As part of the ongoing multinational SENTRY antimicrobial resistance surveillance program, a total of 1,047 respiratory tract isolates of Streptococcus pneumoniae, 845 from 27 United States medical centers and 202 from seven Canadian institutions, were collected between February and June 1997 and characterized in a central laboratory. In the United States, the overall percentages of penicillin-intermediate strains and strains with high-level resistance to penicillin were 27.8% and 16.0%, respectively. In Canada, these values were 21.8% and 8.4%, respectively. Among the 31 centers in the United States and Canada that contributed at least 19 isolates, the combined rate of intermediate plus resistant strains varied between 24.0% and 67.8%. The in vitro activity of 19 other antimicrobials was assessed against all study isolates. Overall rates of resistance among selected agents in the United States and Canada, respectively, were as follows: amoxicillin, 18.1% and 10.5%; cefaclor, 38.3% and 26.2%; cefuroxime, 19.5% and 12.9%; cefpodoxime, 18.6% and 11.4%; cefepime, 8.2% and 4.5%; cefotaxime, 4.0% and 3.0%; macrolides (i.e., erythromycin, azithromycin, and clarithromycin), 11.7%-14.3% and 5.0%-7.4%; clindamycin, 3.5% and 3.5%; chloramphenicol, 3.9% and 4.0%; tetracycline, 10.2% and 10.9%; and trimethoprim-sulfamethoxazole, 19.8% and 15.8%.

Drug Resistance, Microbial↗
PubMed1998

Intravenous lipid emulsions are the major determinant of coagulase-negative staphylococcal bacteremia in very low birth weight newborns.

BACKGROUND: Intravenous lipid emulsions and the i.v. catheters through which they were administered were the major risk factors for nosocomial coagulase-negative staphylococcal (CONS) bacteremia among newborns in our neonatal intensive care units a decade ago. However, medical practice is changing, and these and other interventions may have different effects in the current setting. OBJECTIVES: We determined the independent risk factors for CONS bacteremia in current very low birth weight newborns after adjusting for severity of underlying illness. METHODS: We surveyed 590 consecutively admitted newborns with birth weights < 1500 g hospitalized in 2 neonatal intensive care units and conducted a case-control study in a sample of 74 cases of CONS bacteremia and 74 pairs of matched controls. Adjusted relative odds of bacteremia were estimated for a number of attributes and therapeutic interventions in 2 time intervals before CONS bacteremia: any time before bacteremia and the week before bacteremia. RESULTS: Using conditional logistic regression to adjust for indicators of severity of illness, two procedures were independently associated with subsequent risk of CONS bacteremia at any time during hospitalization: i.v. lipids, odds ratio (OR) = 9.4 [95% confidence interval (CI) 1.2 to 74.2]; and any surgical or percutaneously placed central venous catheter, OR = 2.0 (95% CI 1.1 to 3.9). Considering only the week immediately preceding bacteremia, the independent risk factors were: mechanical ventilation, OR = 3.2 (95% CI 1.3 to 7.6); and short peripheral venous catheters, OR = 2.6 (95% CI 1.0 to 6.5). CONCLUSIONS: During the last decade exposure to i.v. lipids any time during hospitalization has become an even more important risk factor for CONS bacteremia (OR = 9.4). Of these bacteremias 85% are now attributable to lipid therapy. In contrast the relative importance of intravenous catheters as independent risk factors has declined. Mechanical ventilation in the week before bacteremia has emerged as a risk factor for bacteremia.

Bacteremia↗
PubMed1998

Training family medicine faculty to teach in underserved settings.

BACKGROUND AND OBJECTIVES: Because minority physicians are more likely to practice in minority or medically underserved communities, meeting the health care needs of underserved populations requires that programs not only train such physicians but train minority faculty to act as teachers and role models. The Faculty Development Center in Family Medicine at Cook County Hospital has had more than 120 graduates, most of whom are teaching and practicing in underserved settings. Nearly half have been minorities, the result of the priority given to recruitment of minority fellows. The curriculum is specifically geared to prepare faculty to work in underserved settings and nurture future physicians for these settings. Workforce diversity can be achieved only by major changes in the institutional culture of medical education, which federal policy can encourage by setting high standards for grant funding preferences and supporting centers of excellence for training minority physicians and faculty.

Chicago↗
PubMed1998

Promises made.

Explore the source record for details and available documents.

Humans↗