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Biomedical subjects

R Baker

Publications and source records attributed to R Baker.

At least 289 records · Page 16Linked to original sources
PubMed1995

Innovation in general practice: is the gap between training and non-training practices getting wider?

BACKGROUND: Training practices are more developed than non-training practices in terms of a wide range of educational and clinical activities, facilities and staff. If training practices are also adopting new innovations at a faster rate than non-training practices the gap between them will increase. AIM: The aim of this study was to determine whether, between 1982 and 1990, training practices did develop at a faster rate than non-training practices. METHOD: In 1982 a questionnaire was sent to 153 practices in Gloucestershire, Avon and Somerset which all had one or more partners who were members of the Royal College of General Practitioners. A second questionnaire was sent to the same practices in 1990. Information was sought about practice features including organization, size, facilities, staff and clinical and educational activities. A total of 124 practices (62 training and non-training) completed questionnaires on both occasions. RESULTS: There were substantial changes in the cohort between the surveys in 1982 and 1990, with many practices gaining, for example, a practice manager, practice nurse and purpose built premises, and introducing audits, screening activities and specific clinics. For each feature of practice a logistic regression was undertaken with training used as an explanatory variable. Training practices were more likely to develop than non-training practices for a number of features including personnel, aspects of practice organization, educational activities, clinical activities and equipment. CONCLUSION: Training practices are not only more developed than non-training practices but are also more innovative. The gap between training and non-training practices did grow wider between 1982 and 1990. This may be because the members of training practices are inherently more innovative, face fewer obstacles to innovation or that the scheme for approval of practices for training has encouraged specific innovations. Any future accreditation scheme for general practices must be organized to encourage accelerated development in less developed practices rather than only stimulate innovation in already advanced practices.

Education, Medical, Continuing↗
PubMed1995

Use of a single solution for oral rehydration and maintenance therapy of infants with diarrhea and mild to moderate dehydration.

OBJECTIVE: To compare the efficacy of two commonly used solutions in the rehydration of infants with mild to moderate dehydration caused by acute diarrhea in the United States. DESIGN AND SETTING: Double-blind, parallel-group, randomized study performed at Children's Hospital Medical Center. PATIENTS: Sixty infant boys (< or = 2 years old), with mild (< or = 5%) or moderate (6 to 9%) dehydration caused by acute diarrhea of less than 1 week's duration were included in the study. INTERVENTIONS: Infants were randomly assigned to receive treatment with either a glucose-based oral rehydration solution (ORS) (Pedialyte, Ross Laboratories, Columbus, OH) or a rice syrup solids-based ORS (Infalyte, Mead Johnson Nutritional Group, Evansville, IN). After rehydration was achieved, patients entered a maintenance phase during which, in addition to a maintenance ORS, breast milk or a soy-based formula was offered; infants older than 1 year were also given a lactose-free diet. OUTCOME MEASURES: Rehydration was judged clinically. Infants remained on a metabolic bed during the study in to separate and quantitate urine and stool output. Therefore, in addition to clinical outcome, we compared intake, output and apparent absorption and retention of fluid, sodium, and potassium between groups. RESULTS: All patients were successfully rehydrated using an ORS without the use of intravenous fluids. No differences were detected between treatment groups in time to rehydration, percentage of weight gain after rehydration, consumption of ORS to achieve rehydration, or stool output. However, the apparent sodium absorption (net intake less fecal output) was greater in the Infalyte group than the Pedialyte group during the first 24 hours. CONCLUSION: The two maintenance oral electrolyte solutions (Pedialyte and Infalyte) most commonly used in the United States are effective as rehydration solutions for infants with mild to moderate dehydration. We speculate that a strategy for oral rehydration therapy in the United States, based on the use of a single solution during the rehydration and maintenance phase, might gain additional acceptance by practicing pediatricians and family physicians.

Acute Disease↗
PubMed1995

Effects of nine weeks' use of a new stabilized stannous fluoride dentifrice on intrinsic plaque virulence expressed as acidogenicity and regrowth: a modified PGRM study.

A new stabilized stannous fluoride dentifrice, currently marketed as Crest Gum Care has been examined for its effects on intrinsic plaque metabolic and regrowth activity and effects on plaque resistance to SnF2 throughout nine weeks of toothbrushing. Subjects brushed their teeth 1 X, 2 X or 3 X/day with stabilized stannous fluoride dentifrice or placebo dentifrice for nine weeks, presenting in the morning on weeks 3, 6-9 for plaque sampling. Following nine weeks, subjects were crossed-over and repeated the experiment on their alternative assigned product (active SnF2/placebo). Sampled dental plaques were evaluated for standardized glycolysis and regrowth activity using the "Plaque Glycolysis and Regrowth Method" (PGRM). Following the second nine-week treatment period, subjects concluding either placebo or SnF2 toothbrushing participated in a single-treatment PGRM experiment using stabilized stannous fluoride dentifrice. Toothbrushing with stabilized stannous fluoride dentifrice in this experiment produced significant and sustained reductions in both plaque glycolytic and regrowth activity as compared to placebo treated plaques. In the concluding single-brushing PGRM experiment, SnF2 dentifrice was shown to produce equal inhibitory actions in plaque from subjects completing stannous fluoride or placebo treatments. This result confirmed that nine weeks toothbrushing with stabilized stannous fluoride dentifrice produced no development or resistance of plaque to SnF2 inhibition. These results support the strong in vivo antimicrobial actions of the stabilized stannous fluoride dentifrice, Crest Gum Care.

Analysis of Variance↗
PubMed1995

What type of general practice do patients prefer? Exploration of practice characteristics influencing patient satisfaction.

BACKGROUND: General practice is currently experiencing a large number of developments. Studies of patient satisfaction are required to guide the changes that many general practitioners are introducing. AIM: A study set out to examine the characteristics of general practices that influence patient satisfaction. METHOD: In 1991-92, a surgery satisfaction questionnaire of demonstrated reliability and validity was administered to 220 patients in each of 89 general practices. A further questionnaire completed by a member of practice staff collected information about practice characteristics including total list size, number, age and sex of practice partners, training status, fundholding status, presence of a practice manager and whether there was a personal list system. Stepwise multiple regression analyses were undertaken to identify those practice characteristics that influenced patient satisfaction. RESULTS: The mean of the response rates of patients completing questionnaires in each practice was 82%. An increasing total list size of patients registered with practices was associated with decreasing levels of general satisfaction and decreased satisfaction with accessibility, availability, continuity of care, medical care and premises. The presence of a personal list system was associated with increased levels of general satisfaction and increased satisfaction with accessibility, availability, continuity of care and medical care. Training practices were associated with decreased levels of general satisfaction and decreased satisfaction with availability and continuity of care. CONCLUSION: The patients of practices in this study preferred smaller practices, non-training practices and practices that had personal list systems. Practice organization should be reviewed in order to ensure that the trend towards larger practices that provide a wider range of services does not lead to a decline in patient satisfaction. General practitioners should have personal list systems and consider the creation of several personal teams within the practice consisting of small numbers of doctors, receptionists and practice nurses.

Adolescent↗
PubMed1994

Synthesis and biological activity of 3-[2-(dimethylamino)ethyl]-5-[(1,1-dioxo-5-methyl-1,2,5-thiadiazolidin- 2-yl)-methyl]-1H-indole and analogues: agonists for the 5-HT1D receptor.

A novel series of 5-(1,1-dioxo-1,2,5-thiadiazolidin-2-yl)tryptamines was designed, synthesized, and evaluated as 5-HT1D receptor agonists. Compounds such as 8d,f,k were identified which had comparable affinity, potency, and receptor selectivity to that of the antimigraine drug sumatriptan. Both 8d,k were found to be well absorbed in the rat with oral bioavailabilities of 66% and 62%, respectively. Additionally, 8d was found to be selective over other non-serotonergic receptors and exhibited relatively low central nervous system penetration.

Animals↗
PubMed1994

Mechanism of inositol monophosphatase, the putative target of lithium therapy.

myo-Inositol monophosphatase (myo-inositol-1-phosphate phosphohydrolase, EC 3.1.3.25) is an attractive target for mechanistic investigation due to its critical role in the phosphatidylinositol signaling pathway and the possible relevance of its inhibition by Li+ to manic depression therapy. The x-ray crystallographic structure of human inositol monophosphatase in the presence of the inhibitory metal Gd3+ showed only one metal bound per active site, whereas in the presence of Mn2+, three ions were present with one being displaced upon phosphate binding. We report here modeling, kinetic, and mutagenesis studies on the enzyme, which reveal the requirement for two metal ions in the catalytic mechanism. Activity titration curves with Zn2+ or Mn2+ in the presence or absence of Mg2+ are consistent with a two-metal mechanism. Modeling studies based on the various x-ray crystallographic structures (including those with Gd3+ and substrate bound) further support a two-metal mechanism and define the positions of the two metal ions relative to substrate. While the first metal ion may activate water for nucleophilic attack, a second metal ion, coordinated by three aspartate residues, appears to act as a Lewis acid, stabilizing the leaving inositol oxyanion. In this model, the 6-OH group of substrate acts as a ligand for this second metal ion, consistent with the reduced catalytic activity observed with substrate analogues lacking the 6-OH. Evidence from Tb3+ fluorescence quenching and the two-metal kinetic titration curves suggests that Li+ binds at the site of this second metal ion.

Amino Acid Sequence↗
PubMed1994

Eye position and eye velocity integrators reside in separate brainstem nuclei.

Two types of central nervous system integrators are critical for oculomotor performance. The first integrates velocity commands to create position signals that hold fixation of the eye. The second stores relative velocity of the head and visual surround to stabilize gaze both during and after the occurrence of continuous self and world motion. We have used recordings from single neurons to establish that the "position" and "velocity" integrators for horizontal eye movement occupy adjacent, but nonoverlapping, locations in the goldfish medulla. Lidocaine inactivation of each integrator results in the eye movement deficits expected if horizontal eye position and velocity signals are processed separately. These observations also indicate that each brainstem compartment generates and stores these signals. Consequently, each integrator exhibits functional autonomy. Therefore, we propose that the intrinsic electrophysiological properties of the constituent neurons in each brainstem subnucleus may be sufficient for producing integrator rhythmicity.

Animals↗
PubMed1994

Developmental relations between sixth nerve motor neurons and their targets in the chick embryo.

The developmental relations between abducens (VI) nerves and their targets, the lateral rectus, quadratus, and pyramidalis muscles, have been examined in the chick embryo from early neural tube stages through 10 days of incubation. Sites of myoblast origins were determined by microinjection of replication-incompetent retroviruses containing the LacZ reporter into paraxial mesoderm corresponding to somitomeres 3-5. Motor neurons and axons were identified by Bodian staining, immunocytochemistry, and application of DiI and DiO to dissected peripheral nerves. Anlage of the dorsal oblique originate in somitomere 3, close to the ventrolateral margin of the mid-to-caudal mesencephalon. Precursors of the lateral rectus arise deep within somitomere 4, beside the future metencephalon (rhombomere "A"). Quadratus and pyramidalis precursors are located between and partially segregated from these other two anlage. VIth nerve axons exit rhombomeres 5 and 6 via multiple median roots, fasciculate, and by stage 17 have elongated rostrally beneath the hindbrain. Immediately caudal to a mesenchymal pre-muscle condensation located deep to rhombomere 2, the VIth nerve separates into two branches. One branch enters the rostral portion of the condensation, from which quadratus and pyramidalis muscles will segregate. This branch projects exclusively from rhombomere 5 and is the accessory abducens nerve. The other branch enters the caudal, presumptive lateral rectus, region of the condensation. This is the abducens nerve, and it projects from cells located in both rhombomeres 5 and 6. These findings indicate that specific matching of motor nerves with their presumptive targets begins prior to the differentiation and segregation of myogenic populations, and that spatial organization of developing eye muscles is initiated well before they interact with connective tissue precursors derived from the neural crest.

Abducens Nerve↗
PubMed1994

Prevention of relapse of histoplasmosis with fluconazole in patients with the acquired immunodeficiency syndrome.

OBJECTIVE: To assess the effectiveness of fluconazole for suppression of relapse of histoplasmosis in patients with acquired immunodeficiency syndrome (AIDS). DESIGN: Retrospective, nonrandomized, open trial. SETTING: Multicenter at two university referral centers and in five private practices. PATIENTS: Seventy-six patients with AIDS and disseminated histoplasmosis who completed induction treatment with amphotericin B, itraconazole, or fluconazole and maintained on treatment with fluconazole to prevent relapse. INTERVENTIONS: Fluconazole was given at dosages of 100 to 400 mg per day. Patients were followed by their primary physicians, who completed questionnaires collecting information about treatment and relapse status. Blood and urine specimens were submitted periodically for Histoplasma capsulatum var. capsulatum antigen determination. MEASUREMENTS AND MAIN RESULTS: Nine of the 76 patients relapsed during fluconazole therapy and another was removed from the study because of allergic rash. Survival after initiation of therapy for histoplasmosis was 94 weeks, ranging from 74 weeks for those who received less than 1 g of amphotericin B for induction and none for maintenance therapy to 156 weeks for those who received greater than 1 g for induction and additional amphotericin B for maintenance therapy before beginning fluconazole (P < 0.02). Antigen levels fell at rates of 0.05 units/week in urine and 0.02 units/week in serum in patients who were successfully maintained in remission and increased by > or = 2 units/week in 4 of 6 patients who relapsed. CONCLUSIONS: Fluconazole > or = 200 mg daily is a reasonable choice for chronic suppressive therapy of histoplasmosis in patients who cannot take itraconazole because of drug interactions, malabsorption, or side effects.

AIDS-Related Opportunistic Infections↗
PubMed1994

Hurricane Andrew and a pediatric emergency department.

STUDY OBJECTIVE: To determine the effect of Hurricane Andrew on a pediatric emergency department. DESIGN: A retrospective analysis of ED visits through the use of computerized records and chart review. SETTING: A children's hospital in South Florida. TYPE OF PARTICIPANTS: All patients presenting to the ED during the control week and the two study weeks after the hurricane. MEASUREMENTS: Census, diagnoses, admission rate, and patient geographic origin and age. MAIN RESULTS: During week 1, there was an average daily increase of 40.7% in patient volume (P < .01) and a 3.3% decrease in the admission rate (P < .01). The increased census was due mainly to local patients, rather than those from the most devastated areas. More patients were seen with open wounds, gastroenteritis, and impetigo (all, P < .05); more were more than 18 years old (P < .05). By the second week, both census and admission rate returned to normal; cases of cellulitis (P < .05) and open wounds (P < .001) were increased. Although not statistically significant, a higher percentage of hydrocarbon and/or bleach ingestions was seen for both weeks. CONCLUSION: Following a hurricane, personnel in a pediatric ED can expect to see an increased census, with more diagnoses of open wounds, gastroenteritis, and skin infections. They may also see hydrocarbon and bleach ingestions. Alerting parents to the potential for injury and accidental poisoning in their children after a hurricane may help prevent the reported morbidity.

Adolescent↗