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Biomedical subjects

B Porter

Publications and source records attributed to B Porter.

At least 73 records · Page 4Linked to original sources
PubMed1988

Bile acids with a cyclopropyl-containing side chain. 3. Separation, identification, and properties of all four stereoisomers of 3 alpha,7 beta-dihydroxy-22,23-methylene-5 beta-cholan-24-oic acid.

3 alpha,7 beta-Dihydroxy-22,23-methylene-5 beta-cholan-24-oic acid (CUDCA) (2a), a side-chain cyclopropylog of ursodeoxycholic acid (UDCA) was shown to be a mixture of four stereoisomers (CUDCA A-D). The 22S,23R, and 22R,23S diastereoisomers have been separated, their respective configurations assigned by 13C NMR spectroscopy, and original synthetic schemes for their preparation elaborated. Moreover, theoretical models of the structure of UDCA and CUDCA A-D were built by using molecular computer graphic techniques. It was shown that the four diastereoisomers greatly differ in hydrophilicity, in critical micellar concentration (CMC) in water, and exhibit a different interaction with intestinal bacterial enzymes. It was also shown that CUDCA A-C are not conjugated with glycine or taurine in the liver, while CUDCA D is secreted into bile predominantly as taurine and glycine conjugate.

Animals↗
PubMed1987

Coccidioidomycosis in the acquired immunodeficiency syndrome.

Of 27 patients with the acquired immunodeficiency syndrome (AIDS) in Tucson, Arizona, 7 had concurrent coccidioidomycosis. Early manifestations of infection in 6 patients included diffuse nodular pulmonary infiltrates and Coccidioides immitis in many extrathoracic sites. By comparison, a retrospective review of the cases of 300 patients hospitalized with coccidioidal infection identified only 13 patients without AIDS who had the same extent of infection, and only 3 of these patients had no immunosuppressing conditions. Antibodies for coccidioidal antigens at serum dilutions as high as 1:2048 were detected in 5 of the 7 patients with AIDS. Six had temporary responses to amphotericin B treatment, taken both alone and combined with ketoconazole, but all died within 14 months of their diagnosis of coccidioidomycosis. Because annual rates of coccidioidal infection in the Tucson area are 4% or less, the rate of 27% that we calculated, based on 7 patients having the infection during 26 years of risk for AIDS, suggests frequent reactivation of the infection or enhanced susceptibility to endemic exposure in persons with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Synthesis of a functional F0 sector of the Escherichia coli H+-ATPase does not require synthesis of the alpha or beta subunits of F1.

The uncB, E, F, and H genes of the Escherichia coli unc operon were cloned behind the lac promoter of plasmid pUC9, generating plasmid pBP101. These unc loci code, respectively, for the chi, omega, and psi subunits of the F0 sector and the delta subunit of the F1 sector of the H+-ATP synthase complex. Induction of expression of the four unc genes by the addition of isopropyl-beta-D-thiogalactoside resulted in inhibition of growth. During isopropyl-beta-D-thiogalactoside induction, the three subunits of F0 were integrated into the cytoplasmic membrane with a resultant increase in H+ permeability. A functional F0 was formed from plasmid pBP101 in a genetic background lacking all eight of the unc structural genes coding the F1F0 complex. In the unc deletion background, a reasonable correlation was observed between the amount of F0 incorporated into the membrane and the function measured, i.e., high-affinity binding of F1 and rate of F0-mediated H+ translocation. This correlation indicates that most or all of the F0 assembled in the membrane is active. Although the F0 assembled under these conditions binds F1, only partial restoration of NADH-dependent or ATP-dependent quenching of quinacrine fluorescence was observed with these membranes. Proteolysis of a fraction of the psi subunit may account for this partial deficiency. The experiments described demonstrate that a functional F0 can be assembled in vivo in E. coli strains lacking genes for the alpha, beta, gamma, and epsilon subunits of F1.

Bacterial Proteins↗
PubMed1985

Clinical competence of paediatric primary health care nurses in Soweto.

Primary health care (PHC) nurses provide care at polyclinics in Soweto. Our study assessed nurse competence in the clinical detection of important respiratory signs in 337 consecutive paediatric patients with respiratory complaints. The patients were then independently re-examined by two paediatricians, one of whom was arbitrarily chosen as a 'standard doctor'. The standard doctor found 95 patients with important respiratory signs; nurses detected the same signs in 45 and the other doctor in 44 patients. Therefore nurses detected important signs as well as could be expected, considering the inter-observer variation between doctors. The nurses did, however, significantly overdiagnose one condition, follicular tonsillitis. Our results suggest that the Soweto paediatric PHC nurses detect clinical signs with as much accuracy as doctors. This study adds to the available evidence that adequately trained and supervised nurse practitioners can provide high-quality health care.

Clinical Competence↗
PubMed1984

An outbreak of shigellosis in an ultra-orthodox Jewish community.

An outbreak of Shigellosis due to Shigella sonnei, S. flexnerii and S. boydii in an ultra-religious Jewish community in Southern Israel is described. The source of epidemic was traced to vegetables bought from a single source. The importance of epidemic and endemic modes of spread of Shigella is discussed.

Adolescent↗
PubMed1983

Identification of a carrier by using Vi enzyme-linked immunosorbent assay serology in an outbreak of typhoid fever on an Indian reservation.

In May 1981 an outbreak of typhoid fever occurred in a small village on a southwestern United States Indian reservation. Five of the six culture-proven cases, but only 2 of 15 community, age-matched controls, had eaten food prepared for a party held in the village on 20 April (chi-square = 4.3; P less than 0.05). Food histories obtained from 16 persons who ate food at the party suggested that chicken with chili (P = 0.03) and potato salad (P = 0.09) were possible vehicles. Eleven adults who attended the party, 5 of whom helped prepare an implicated food, were studied with one or more stool cultures and serum for Vi antibody by using enzyme-linked immunosorbent assay (ELISA) and hemagglutination techniques. All initial stool cultures were negative for Salmonella typhi; however, one subject, a 70-year-old female foodhandler, had a Vi antibody titer of 1:320 by ELISA. Subsequent cultures from this subject were positive for S. typhi. ELISA for Vi antibody directed the investigators to a single individual as the most probable carrier source and obviated the need for multiple fecal cultures from the other potential carriers identified by the epidemiological investigation.

Adult↗
PubMed1983

Primary care pediatrics vs. family practice: a nonissue.

As in other areas of the world, in Israel there is an ongoing discussion about who should provide primary health care for children--the family physician or a pediatric specialist. Since the problem should be defined in terms of the health needs of the child, and not in terms of the social groupings of the medical profession, a primary care pediatric model, such as that established by the Health Sciences Center of the Ben-Gurion University of the Negev in Ofakim, could serve as a prototype for comparison with family practice clinics to see which is closer to the needs of children.

Child↗
PubMed1982

A model for comparison of local anesthetics in man.

Ten patients scheduled for bilateral arm surgery were given general anesthesia plus, on one side, an axillary brachial plexus block. Ten additional patients scheduled for bilateral foot surgery were similarly given general anesthesia plus an ankle block on one side. A within-patient blind comparison of postoperative analgesia between blocked and unblocked side was performed. An additional 10 patients scheduled for bilateral foot surgery had one side blocked with lidocaine and the other side blocked with bupivacaine for comparison of postoperative analgesia. Postoperative analgesia recorded by a nurse observed was significantly better on the blocked side compared with the unblocked side. This difference was greater for ankle blocks. There were no differences between the analgesic measures for lidocaine and bupivacaine ankle blocks over the 6-hour study period.

Adolescent↗
PubMed1981

[Infantile rumination].

In a 3-month-old baby with recurrent vomiting, infantile rumination syndrome was diagnosed on the basis of the typical behavior, absence of any physical or radiological findings and failure of pharmacological treatment. The therapeutic approach, which consisted of daily visits to the clinic by the mother and effective psychological support by the pediatrician and the nurses, caused prompt improvement and indicated the importance of diagnosis and treatment in the ambulatory clinic.

Ambulatory Care↗
PubMed1981

Percutaneous cytodiagnosis of abdominal masses by ultrasound guided fine needle aspiration biopsy.

A review was made of 168 ultrasound guided fine needle biopsies on 145 patients. Fifty-seven biopsies were from the pancreas, 40 biopsies from the liver, 28 from the kidney, 26 from the abdomen and 17 from the retroperitoneum. The total accuracy rate was 66 per cent varying from 50 per cent in abdominal lesions to 83 per cent in hepatic lesions. The differences of the results are discussed as are the indications and the role of ultrasound guided fine needle puncture compared with other modalities.

Abdominal Neoplasms↗
PubMed1980

Marital discord and childhood behavior problems.

Measures of overt marital hostility, general marital adjustment, and children's behavior problems were obtained from the parents of 64 children referred to a child psychological clinic. Correlations between children's scores on measures of general marital unhappiness and overt marital hostility were compared. Overt marital hostility correlated significantly with many behavior problems of boys. However, neither general marital unhappiness nor overt marital hostility related to problem behaviors in girls. Specific findings and possible reasons for the differential results with respect to boys and girls were discussed.

Adolescent↗
PubMed1979

Reliability of the middle ear examination.

Interobserver reliability of physical signs elicited and diagnoses made on middle ear examination were studied. Effect on reliability of variation in observer knowledge, patient age and instrument were defined. Two board-certified, color-seeing pediatric specialists who worked in the same clinic examined consecutively 350 ears with the same otoscope for each case. Over a period of four months, four different otoscopes were used to examine at least 50 ears with each. The following groups of findings were graded independently by the pediatrician according to pre-set criteria: color, landmarks and light reflex. Diagnosis was also recorded. At no time did the observers discuss their findings or diagnoses. Degree of interobserver agreement was expressed by the reliability coefficient (values given below) and the K coefficient. Overall agreement on findings ranged from 0.50 for landmarks to 0.85 for air-fluid level. Overall agreement for diagnoses was 0.72. Specific agreement on physical findings ranged from 0.0 for presence of air-fluid level to 0.85 for absence of air-fluid level. Specific agreement on diagnoses ranged from 0.08 on serous otitis to 0.56 on otitis media and 0.61 on normal. After the age of one year, agreement did not increase with age. Agreement did not change significantly with different instruments or as the study progressed. We concluded that equivalence of observer knowledge strongly increases agreement, while patient age less than one year decreases agreement, and type of instrument does not affect agreement. Clinicians should be trained to recognized middle ear signs and diagnoses according to specified criteria to maximize interobserver agreement.

Age Factors↗
PubMed1978

Cadmium exposure in a community near a smelter.

In June, 1976, the authors conducted a cross-sectional survey of a community near a cadmium smelter in Denver, Colorado, to evaluate human cadmium absorption and its possible health effects. In 1975 the mean annual airborne cadmium concentration in an area about 1 km from the smelter was 0.023 microgram/m3; the mean concentration in a comparison area 13 km distant was 0.003 microgram/m3. Whole blood and urine specimens were collected from 250 individuals residing within 2 km of the smelter and from a control population of 105 residents in the comparison area. There were no significant differences (p greater than .05) in whole blood or urine cadmium concentrations, as determined by flameless atomic absorption spectrophotometry, between persons in the two areas. The median blood and urine cadmium concentrations of residents within 1 km of the smelter were 0.05 and 0.09 microgram/100 ml, compared with 0.07 and 0.08 microgram/100 ml for control area residents. However, the difference between blood cadmium levels for smokers and nonsmokers was statistically significant (p less than .01). The median blood cadmium concentration for smokers was 0.21 microgram/100 ml compared with 0.04 microgram/100 ml for nonsmokers. Other laboratory determinations of blood and urine showed no evidence of a cadmium effect on hematopoietic or renal function.

Absorption↗
PubMed1976

Tay-Sachs disease in a Moroccan Jewish family: a possible new mutation.

The parents of a Jewish Moroccan family, in which a previous child had died of Tay-Sachs disease, both proved to be carriers of the mutant gene. Hexosaminidase A activity in the father was similar to that in Ashkenazic heterozygotes, while the mother showed extremely low hexosaminidase A activity in peripheral leukocytes. Amniocentesis was performed on the mother during a subsequent pregnancy; the fetus proved to be affected and the pregnancy was interrupted. Acrylamide isoelectrofocusing of fetal liver and leukocytes of additional family members revealed a variant mutation for Tay-Sachs disease.

Amniocentesis↗