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Biomedical subjects

D Jackson

Publications and source records attributed to D Jackson.

At least 235 records · Page 13Linked to original sources
PubMed1983

Childhood lead poisoning. A controlled trial of the effect of dust-control measures on blood lead levels.

Lead-contaminated house dust is one factor in childhood lead poisoning; however, most lead-reduction programs do not emphasize the control of house dust. We studied whether lead-reduction plus dust-control measures would lower blood lead levels in children with Class II or III poisoning (blood lead levels, 30 to 49 micrograms per deciliter) more effectively than lead reduction alone. An experimental group of 14 children and a control group of 35 children whose homes had already been treated were studied. In experimental homes, sites with elevated lead levels (greater than 100 micrograms per 930 cm2) were wet-mopped twice monthly and families were encouraged to clean and to wash the child's hands frequently. After one year blood lead levels fell an average of 6.9 micrograms per deciliter in the experimental group, as compared with 0.7 micrograms per deciliter in controls (P less than 0.001). Children in the experimental group with the highest blood lead levels had the most marked reduction. Four children in the control group (and none in the experimental group) required chelation therapy for blood levels greater than 50 micrograms per deciliter. These results show that a focused dust-control program can reduce blood lead levels more than standard lead removal in the home.

Child↗
PubMed1983

Subsequent reproductive outcome in couples with repeated pregnancy loss.

While the role of cytogenetic study in couples with repeated pregnancy loss is well-established, little information is available for counseling these couples concerning future reproductive outcome. Couples evaluated by chromosome analysis for recurrent abortion between 1972 and 1979 were contacted by phone in 1981. Of those studied cytogenetically, 195 couples (50.1%) could be located, and information concerning outcome of subsequent pregnancies were obtained. Couples (91) with two consecutive pregnancy losses at the time of initial investigation had a 31.3% subsequent abortion rate, but most (68%) had at least one liveborn child. The rate of infertility following evaluation was slightly increased (18.7%), but that of prematurity (11.2%) and congenital anomalies (2.5%) was not. In contrast, couples with greater than or equal to 3 consecutive losses (84) experienced abortion in 45.7% of subsequent pregnancies, and only 54.8% of them eventually had a liveborn child. Again, the rate of infertility was increased (26.2%), but that of prematurity (10%) and congenital defects (3.2%) was not. Nine couples in which one individual was found to have a chromosome abnormality (two inversions and seven translocations) were considered separately. Of these, seven couples had nine liveborn offspring. Amniocentesis was performed in eight cases, with karyotypes showing a balanced translocation identical to that of the parent in 2. All children were phenotypically normal.

Abortion, Habitual↗
PubMed1983

Comparative studies of the effect of thermal stimulation on the permeability of the luminal cell junctions of the sweat gland to lanthanum.

Lanthanum injected intradermally in vivo into the skin of cattle, sheep, goats and ponies penetrated the intercellular spaces of the sweat glands. It was not, however, detected in the glandular lumen either visually or by electron probe microanalysis even at elevated ambient temperatures when the animals were sweating. It is concluded that the luminal intercellular connections between epithelial cells in these glands are tight junctions, which remain so during sweating despite the occurrence of cell death and extrusion into the lumen.

Animals↗
PubMed1983

Molecular analysis of rearrangements in human ribosomal RNA gene clones.

Human placental DNA, enriched for ribosomal sequences, was cloned in the phage vector lambda Charon 16A. Recombinants containing 28S rDNA sequences were isolated, and all were found to have deletions in the insert and/or vector DNA. Electron microscopic analysis was used to map the deletions and provide evidence that unstable forms of the recombinants can revert to the original vector or undergo further rearrangements. Specific deletions are manifested as previously unreported plaque phenotypes.

Bacteriophage lambda↗
PubMed1983

Open reading frame expression vectors: a general method for antigen production in Escherichia coli using protein fusions to beta-galactosidase.

We have developed an Escherichia coli plasmid vector for the identification and expression of foreign DNA segments that are open reading frames (ORFs). The 5' end of ompF, an E. coli gene encoding an abundant outer membrane protein, is used to provide a strong, regulated promoter, translation initiation site, and signal sequence for export from the cytoplasm. This sequence is coupled to the lacZ gene of E. coli so that expression of beta-galactosidase requires ompF transcription and translation signals. However, this hybrid gene is LacZ- because lacZ is out of frame with respect to ompF. Restriction enzyme recognition sites are located between ompF and lacZ to allow convenient insertion of DNA fragments. If an insert is an ORF of the correct length, ompF and lacZ become realigned in frame, resulting in a LacZ+ gene that produces a tribrid protein with the translation product of the insert sandwiched between OmpF and beta-galactosidase. The LacZ+ phenotype thus identifies clones containing an expressed ORF. To demonstrate the vector's utility we inserted a fragment from the herpes virus thymidine kinase gene and used the resulting tribrid protein to raise antibodies that precipitate thymidine kinase from herpes virus-infected cells. We also inserted a fragment from the E. coli lexA gene to produce a tribrid protein that is precipitated by antiserum raised with LexA protein. Thus, tribrid fusion proteins can be used to produce or detect antibodies and also to identify the product of a cloned gene.

Antigens, Bacterial↗
PubMed1983

Amoxycillin/clavulanic acid: the effect of probenecid.

The effect of probenecid on the combination of amoxycillin/clavulanic acid has been compared with the effect on amoxycillin alone and it has been shown that probenecid, whilst producing its expected effect on amoxycillin, did not affect the clavulanic acid concentration of the combination. A possible minor role for tubular secretion of clavulanic acid is discussed.

Adult↗
PubMed1983

Discharge decision-making in a medical ICU: characteristics of unexpected readmissions.

To identify those patients most likely to be readmitted to a Medical ICU (MICU), we studied 512 MICU admissions during a 1-yr period. There were 36 readmissions within the same hospitalization in that interval. When ICU deaths and short-term drug overdoses were excluded, these 36 readmissions comprised 12% of all patients discharged from MICU. The mortality rate of this group was 58%, greater than twice the overall mortality rate for the year. Fifty-three % of the patients were readmitted because of recurrence of their initial disease on admission, with septicemia being the most common disease. Another 30% were readmitted because of a new complication, one-half of which were medication toxicities. We have attempted to delineate diseases, medications, and complications which may predict the high-risk discharge from MICU. Further studies to identify high-risk and low-risk admissions and discharges will effect better use of intensive care.

Decision Making↗
PubMed1983

Structural variations in pili expressed during gonococcal infection.

Gonococci were cultured from the urethra of male patients and from the cervix and urethra of their female partners. SDS-PAGE of cell lysates from within each group of consorts showed that outer membrane protein I remained constant but considerable variations were seen in the apparent molecular weight of protein II. Pili were purified from the isolates of some groups of consorts. In each case the pili expressed by the isolates from the female cervix and urethra differed in subunit molecular weight and were usually also distinct from the pili expressed by the isolate from the male partner.

Bacterial Outer Membrane Proteins↗
PubMed1983

Biliary excretion of piperacillin.

1. The excretion of piperacillin sodium in bile was studied after intravenous injection of 2 g (n = 5) and 4 g (n = 7). All patients had undergone cholecystectomy and exploration of the common bile duct for cholelithiasis. Bile, serum and urine concentrations were measured by a microbiological technique. 2. Peak concentrations of piperacillin were found in bile at 150 minutes after 4 g and at 210 minutes after 2 g. 3. Both the concentration of piperacillin in bile at the end of a 6 1/2 hour study and the calculated mean bile concentration of piperacillin were above the minimum inhibitory concentration (MIC) of this drug for organisms commonly found in acute biliary tract infections. We believe piperacillin may be useful in the management of such conditions.

Adolescent↗