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Biomedical subjects

R G Thompson

Publications and source records attributed to R G Thompson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Chlamydia trachomatis infection in late pregnancy: a prospective study.

During a 1-year period, 3309 women were screened in pregnancy for Chlamydia trachomatis infection. A cervical swab was taken and chlamydial antigen was detected, using a monoclonal antibody ELISA technique, in 198 women (6%). The prevalence of chlamydial infection was high in women under 20 years (14.5%), single women (14.2%) and black women (16.8%). Binomial regression of these data estimates a relative risk of 2.9 for women under 20 years compared with women aged 25 and over. There was an interaction between race and marital status with a high risk in single white and single asian women (2.3, 4.5 respectively) but a similar risk in black single and black married women (3.0, 4.0 respectively). Parity and social class did not effect the prevalence of antigen carriage. There was no demonstrable effect of maternal antigen carriage on outcome of pregnancy, gestation or admission to neonatal unit. Infants of 174 antigen-positive mothers were followed-up. Tissue culture for Chlamydia trachomatis was positive in 43 (24%) infants. Complications occurred in 23 (53%): 17 had conjunctivitis, three had lower respiratory tract infection and three both complications. Amongst 131 chlamydia-negative infants, complications occurred in 21 (16%). Since this infection, in infants, responds promptly to erythromycin therapy, screening and treatment in pregnancy will convey little benefit in prevention of perinatal morbidity or perinatal mortality.

Adult↗
PubMed1989

Chlamydia trachomatis infection in infants: a prospective study.

In a prospective study of Chlamydia trachomatis infection in pregnancy, 198 mothers positive for chlamydial antigen were identified; the infants of 174 were followed for up to six months and C trachomatis was recovered in cell culture from 43 infants (25%). Conjunctivitis occurred in significantly more infants who were positive for C trachomatis (20 of 43, 47%) than in those who were negative (18 of 131, 14%). There were also significantly more lower respiratory tract infections among infants with positive cultures (six of 43, 14%, compared with three of 131, 2%). The chlamydial antigen enzyme linked immunosorbent assay (ELISA) was positive in 61 of 131 infants from whom C trachomatis was not recovered in cell culture. False positive results were usually associated with the isolation of Staphylococcus aureus from samples of pharyngeal aspirate. Our results confirm that C trachomatis infection is a common cause of neonatal conjunctivitis, and respiratory infection in the first few months of life, with an incidence of 8.2/1000 live births. Because the infection is easily treated by oral erythromycin, however, screening during pregnancy is not warranted.

Chlamydia Infections↗
PubMed1989

Biosynthetic human growth hormone: current status and future questions.

Human growth hormone derived from human pituitaries resulted in excellent growth in children with growth hormone deficiency but limited supplies in many countries prevented treatment of all children, delayed the onset of therapy, and/or forced the use of doses that may have been less than optimal. Recent advances in technology allow the production of byosynthetic human growth hormone (hGH) by recombinant methods resulting in increased supplies of hormone. More than 200 previously untreated children with growth hormone deficiency have been evaluated for two years or longer while receiving biosynthetic natural sequence hGH (somatropin). The mean growth velocity of 3.6 cm/yr prior to therapy increased to 8.8 cm/yr after one year and 7.25 cm/yr in the second year. Growth response was inversely related to age when calculated as cm/yr. This response paralleled the normal decrease in growth velocity as children approach puberty. Children with hGH deficiency who had previously received replacement hGH were enrolled in a double-blind study using either 0.06 or 0.10 mg/kg thrice weekly for 12 months. Growth rate was significantly greater with the higher dose during the first six months but not during the second six month period. The use of a higher dose of hGH must be individualized as not all patients have accelerated growth with the increased dose and the mean group response is not permanent. Multiple questions remain unanswered after three decades of treating growth hormone deficiency. Are the current criteria for diagnosis of growth hormone deficiency appropriate? What dose of hGH is correct? Do children need increases in replacement therapy as their height approaches normal?(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1986

Rates of pi-electron oxidation and reduction of free base and Zn(II) porphyrins, chlorins, and isobacteriochlorins.

The rates of pi-electron oxidation and reduction of two homologous series of free base and Zn(II) porphyrins, chlorins, and isobacteriochlorins were studied by chronocoulometry at a platinum disk electrode. The macrocycles were octaethylporphyrin, tetraphenylporphyrin, and the chlorins and isobacteriochlorins derived therefrom. The rates were found to vary to within a factor of 3, and some consistent trends are noted. However, the most important conclusion of this work is that pi-electron redox processes for these macrocycles occur at essentially the same rate, despite the previously noted large differences in pi-electron redox potentials.

Bacteria↗
PubMed1986

Simple versus complex performance impairments at three blood glucose levels.

By using a visual reaction time paradigm, we sought to determine if disruption of relatively simple responding (finger tapping or letter recognition) or more complex responding (choice reaction time) would occur in response to blood glucose deviations. Glucose levels were maintained in 24 male diabetics to within 4% of the following targeted concentrations: 55 mg/dl (hypoglycemia), 110 mg/dl (euglycemia/control), and 300 mg/dl (hyperglycemia). The results indicate that simple motor and perceptual skills were not affected by blood glucose alterations, while more complex cognitive processing required significantly longer response latencies during hypoglycemia. Performance impairments occurred independently of disease duration and control, and without documented neuropathy, underscoring the sensitivity of some cognitive skills to acute glucose fluctuations.

Adolescent↗
PubMed1985

Computer analysis of double-labeled two-dimensional electrophoresis gels.

A computerized process for the automatic analysis of double-label autoradiography after two-dimensional polyacrylamide gel electrophoresis has been developed. Matching fluorographs and autoradiographs produced from gels containing 3H- and 14C-labeled proteins are digitized by a rotating drum densitometer and analyzed by the Man-computer Interactive Data Analysis System III. This system locates corresponding protein spots in the films with edge-detection algorithms, converts spot density readings to isotopic disintegrations by reference to standard curves, and computes a 3H:14C ratio for each spot in the gels. On the average, calculated ratios are accurate to approximately 9% for test strips of polyacrylamide gel containing uniform mixtures of 3H and 14C. Values obtained for two-dimensional gels containing n protein spots with a known 3H:14C ratio of 8.6 +/- 0.1 are as follows: 8.1 +/- 1.4 (n = 268), 8.8 +/- 2.1 (n = 278), 9.1 +/- 1.7 (n = 245), and 8.8 +/- 2.2 (n = 223). The computer process greatly reduces the time required to precisely compare two complex protein mixtures and has sufficient precision to detect a doubling in the biosynthesis of any individual protein.

Animals↗
PubMed1985

Regulation of NO(3) Influx in Barley : Studies Using NO(3).

Short-term (10 minutes) measurements of plasmalemma NO(3) (-) influx (phi(oc)) into roots of intact barley plants were obtained using (13)NO(3) (-). In plants grown for 4 days at various NO(3) (-) levels (0.1, 0.2, 0.5 millimolar), phi(oc) was found to be independent of the level of NO(3) (-) pretreatment. Similarly, pretreatment with Cl(-) had no effect upon plasmalemma (13)NO(3) (-) influx. Plants grown in the complete absence of (13)NO(3) (-) (in CaSO(4) solutions) subsequently revealed influx values which were more than 50% lower than for plants grown in NO(3) (-). Based upon the documented effects of NO(3) (-) or Cl(-) pretreatments on net uptake of NO(3) (-), these observations suggest that negative feedback from vacuolar NO(3) (-) and/or Cl(-) acts at the tonoplast but not at the plasmalemma. When included in the influx medium, 0.5 millimolar Cl(-) was without effect upon (13)NO(3) (-) influx, but NH(4) (+) caused approximately 50% reduction of influx at this concentration.

Journal Article↗
PubMed1985

Management of infection of major amputation stumps after failed femorodistal grafts.

A retrospective review was performed of 174 patients who underwent 199 lower-extremity amputations for unreconstructable vascular insufficiency from 1976 to 1983 at the Northwestern University Medical Center. This study was initiated to identify the cause of amputation wound healing complications and secondary ascending prosthetic graft infection, as well as to propose a plan of management for the failed prosthetic grafts at the time of major limb amputation. Ninety-eight amputations were performed primarily, 12 were performed secondary to graft infection, and 89 were performed in patients who had previously undergone infrainguinal arterial bypass procedures. At the time of amputation, graft management consisted of high transection and suture ligation, allowing the graft to retract into the substance of the stump and away from the skin suture line and weight-bearing area of the limb. Delayed stump healing was noted to occur more commonly in the group who had undergone previous bypasses as opposed to those who had undergone primary amputation (34.8% versus 14.3%). Fourteen graft infections developed in 89 patients after amputation (15.7%), which is significantly higher than the overall 1.4% incidence of lower-extremity bypass infections that occurred during the same interval in patients with intact extremities. In addition, it was found that when infected grafts in amputated limbs were completely removed, stump healing without recurrent wound and graft sepsis was better than when treated locally or with partial graft removal. We therefore recommend removal of a thrombosed graft with an infected wound or an infected graft at the time of major limb amputation to decrease the incidence of wound complications and graft infection.

Amputation Stumps↗
PubMed1985

Social and school competencies in children with short stature: longitudinal patterns.

Longitudinal evaluation of 47 children with short stature secondary to growth hormone deficiency (GHD), constitutional delay (CD), and Turner's syndrome (TS) was undertaken approximately 3 years after initial assessment. Parent ratings of social and school competence indicated a developmental trend of poorer adjustment during early adolescence (ages 12 and 14), which was preceded (age 9) and followed (age 17) by age-appropriate functioning. Evaluation of social competence scores suggested that large organized group activities were avoided, although children had close friends with whom they interacted regularly. Children with short stature obtained age-expected scores for their involvement in solitary activities (i.e., hobbies and household chores) and tended to participate in individual sports (i.e., fishing, swimming), consistent with a pattern of withdrawal from large groups. Younger children with CD evidenced academic functioning at least 1 SD higher than children from all other groups, and this age-related effect may explain performance inconsistencies reported previously with other groups of CD children. Of the children studied, girls with TS experienced the greatest academic difficulty.

Achievement↗
PubMed1984

The detection of Escherichia coli heat-labile enterotoxin by enzyme-linked immunosorbent assay.

An enzyme linked immunosorbent assay (ELISA) technique was modified and used to detect heat-labile (LT) enterotoxigenic Escherichia coli (ETEC) from specimens of faeces sent to a routine diagnostic laboratory. Strains of LT ETEC were detected in eight of 250 (3.2%) diarrhoeal stools but were not found in 110 non-diarrhoeal stools. All eight patients found to have LT ETEC were travellers returning with diarrhoea. LT ETEC was the most common bacterial pathogen found (15.4%) in this group of patients, exceeding Campylobacter sp. (5.8%) and Salmonella sp. (7.7%). The ELISA technique was simple to perform and visual readings were found to be reliable.

Adult↗
PubMed1984

Ultrasonic Acoustic Emissions from the Sapwood of Thuja occidentalis Measured inside a Pressure Bomb.

An improved method of counting acoustic emission (AE) events from water-stressed stems of cedar (Thuja occidentalis L.) is presented. Amplified AEs are analyzed on a real time basis by a microcomputer. The instrumentation counts AE events in a fashion nearly analogous to scintillation counting of radioactive materials.The technique was applied to measuring ultrasonic AEs from the stems of cedar inside a pressure bomb. The shoots were originally fully hydrated. When the shoots are dehydrated in the bomb by application of an overpressure very few AEs were detected. When the bomb pressure is reduced after dehydration of the shoot, AE events could be detected. We conclude that ultrasonic AEs are caused by cavitation events (= structural breakdown of water columns in the tracheids of cedar) and not by the breaking of cellulose fibers in the wood.

Journal Article↗
PubMed1984

Isolation of Chlamydia using McCoy cells and Buffalo green monkey cells.

Unselected eye and genital specimens from 233 patients were cultured for Chlamydia. The isolation rates were compared using McCoy cells and Buffalo green monkey cells, both procedures being performed with and without the addition of cycloheximide and centrifugation. No significant difference was found in the isolation rates using the four methods. The characteristics of the two cell lines and the advantages of omitting cycloheximide treatment and centrifugation are discussed.

Animals↗
PubMed1982

Hypokalemia after resuscitation from out-of-hospital ventricular fibrillation.

We studied serum electrolyte levels, blood gas values, and diuretic history in 115 patients immediately after resuscitation from out-of-hospital ventricular fibrillation. Comparisons were made with 84 patients admitted for acute myocardial infarction and with 88 ambulatory patients with coronary heart disease. Admission serum potassium values of 3.60 mEq/L or lower were found in 56 (49%) of the resuscitated patients, compared with 16 (19%) and eight (9%) of the comparison groups, respectively. In the resuscitated patients, the mean serum potassium level was 3.70 +/- 0.72 (SD) mEq/L, compared with 4.09 +/- 0.66 and 4.17 +/- 0.35 mEq/L in the respective comparison groups. Reduced serum potassium concentration was not related to simple extracellular alkalosis. However, the absence of a causative relationship to diuretic use suggested that it occurred during cardiac arrest and resuscitation. Rapid correction of extracellular acidosis by bicarbonate therapy and ventilation may have produced a shift of extracellular potassium into the intracellular compartment even in the absence of extracellular alkalosis.

Bicarbonates↗
PubMed1982

Analysis of fibroblast proteins from patients with Duchenne muscular dystrophy by two-dimensional gel electrophoresis.

Duchenne muscular dystrophy (DMD), the most common and severe form of the muscular dystrophies, is an X-linked inborn error of metabolism with multiple tissue involvement. Although the major pathological changes are observed in skeletal muscle, abnormalities have also been detected in the heart, nervous system, red blood cells, lymphocytes and cultured skin fibroblasts. For many reasons, such as readily available tissue material, fewer secondary changes and the potential for prenatal diagnosis, cultured skin fibroblasts should be the tissue of choice to search for the primary defect. Several abnormalities have been reported in DMD fibroblasts, suggesting that the genetic abnormality is expressed in these cells. To search for potentially mutant protein(s) we have compared the protein composition of normal and DMD fibroblasts by two-dimensional gel electrophoresis and have now found one protein spot consistently missing in DMD cells. The nature of this protein and its relation to the DMD gene are unknown.

Autoradiography↗