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Biomedical subjects

D E Jackson

Publications and source records attributed to D E Jackson.

At least 73 records · Page 4Linked to original sources
PubMed1985

Thyroid uptake and imaging with iodine-123 at 4-5 hours: replacement of the 24-hour iodine-131 standard.

A study was carried out to determine the suitability of utilizing a 4 to 5 hr interval from administration of iodine-123 to imaging and uptake measurement as a replacement for the 24-hr standard originally established with iodine-131. In 55 patients who underwent scintigraphy at 4 and 24 hr, there was no discrepancy between paired images. In 55 patients who had uptake measured at 4 and 24 hr and in 191 patients who had uptake measured at 5 and 24 hr, the early measurements proved equal or better discriminants of euthyroid from hyperthyroid patients. In our institutions, these findings and the logistical advantages of completing the exam in 4-5 hr led us to abandon the 24-hr study in the majority of patients.

Adolescent↗
PubMed1984

Monoclonal antibodies to immunodeterminants of lipoteichoic acids.

Murine hybrid cell lines producing monoclonal antibodies directed against determinants present on lipoteichoic acids were generated. Hapten inhibition studies showed that one group of monoclonal antibodies was inhibited by deacylated cardiolipin, and the second group was inhibited by kojibiose. Thus, antibodies directed against the polyglycerophosphate chain, which is common to the lipoteichoic acids of many gram-positive species, and against the streptococcal group D antigen were obtained.

Animals↗
PubMed1984

Selection of lac gene fusions in vivo: ompR-lacZ fusions that define a functional domain of the ompR gene product.

We describe a simple method for selecting Escherichia coli mutants that carry gene fusions between a cloned gene and lacZ. We test this technique with the ompR gene, which codes for a positive regulatory factor in porin synthesis. A number of OmpR-LacZ hybrid proteins are examined, and several unusual phenotypes associated with these protein fusions are described. Evidence is presented to support the two-domain model for ompR proposed previously (Hall and Silhavy, J. Mol. Biol. 151:1-15). In addition, one of the ompR-lacZ fusions exhibits a dominant OmpR- phenotype. The utility of isolating a series of lacZ gene fusions to any target gene is discussed.

Bacterial Outer Membrane Proteins↗
PubMed1981

Induction of IgM immunological memory to lipoteichoic acids in rabbits. Part I.

Intravenous immunisation of rabbits with 10(9) lactobacillus fermentum cells elicited a response, specific for lipoteichoic acid (LTA), detectable as IgM plaque-forming cells (PFC) in the spleen by day 2 and as thiol-sensitive 19s antibodies in sera by day 3. Direct PFC responses peaked at day 6, with no indirect PFC demonstrable at the time. Specific IgG PFC appeared after 14 days. A second intravenous injection 5 weeks later induced a 10-fold higher IgM PFC response to LTA which reached a maximum on day 4. An enhanced specific IgG PFC response was also observed. Serum analysis showed further evidence of the anamnestic IgM response to LTA. The results are discussed in terms of the T-dependence of the LTA immunogen.

Animals↗
PubMed1981

Immune responses to lipoteichoic acid: comparison of antibody responses in rabbits and mice. Part II.

Humoral immune responses to lipoteichoic acid (LTA) as a surface antigen of Lactobacillus fermentum were assessed in rabbits and mice. Intravenous injection of rabbits with whole bacteria was effective, over a wide range of doses (10(4) to 10(10) cells), in eliciting antibodies to LTA. In mice, significant levels of anti-LTA antibodies were induced only following intraperitoneal injection of 10(8) to 10(9) L. fermentum cells. Rabbit antibodies to LTA were predominantly of the IgM class and were specific for the polyglycerol phosphate and carbohydrate moieties of the LTA. In contrast, both IgM and IgG anti-LTA antibodies were produced in the mouse, and antibody specificity was restricted to the polyglycerol phosphate sequence.

Absorption↗
PubMed1981

Induction of hypersensitivity reactions to Lactobacillus fermentum and lipoteichoic acid in rabbits. Part II.

Regimens of intravenous injections of saline-washed Lactobacillus fermentum elicited hypersensitivity reactions in rabbits. Pathological investigation revealed evidence consistent with induction of aggregate anaphylaxis, characterised by acute cor pulmonale. Additional evidence of similar tissue injury was observed in livers of rabbits which had received several intravenous injections of L. fermentum. Deposition of immune complexes in kidney glomeruli was demonstrated in only 1 out of 11 animals. Skin testing experiments revealed that lipoteichoic acid was involved in type I and type II antibody-mediated hypersensitive states. The involvement of bacterial cell surface components and extracellular products in such reactions implies a potential role in host tissue injury.

Animals↗
PubMed1980

Isoelectric focusing of IgA and IgM in composite acrylamide-agarose gels.

A convenient method for isoelectric focusing of intact polymeric IgA and IgM is described. This technique employed composite gels containing 1.0% acrylamide and 0.75% agarose which exhibited minimal electroendosmotic properties. The spectrotypes obtained with mouse IgA myeloma proteins, a human IgA myeloma and rabbit secretory IgA preparations were compared in three gel systems: 5% acrylamide, 0.8% agarose and the composite gel. With respect to resolution of component bands, the composite gel was superior to the other two systems. Hapten binding studies with MOPC-315 IgA and a rabbit secretory IgA anti-DNP antibody indicated that the focused IgA molecules retained their binding site integrity in the composite gel. The pI ranges obtained with microscale sucrose isoelectric focusing and composite gel system showed good correspondence, with the latter exhibiting enhanced resolution. Studies with MOPC-104E IgM revealed improved resolution in the composite gel when compared to the agarose system. Comparison of pI ranges for IgA and IgM immunoglobulins obtained in the present study with those reported previously suggest that IgA spectrotypes are confined to an acidic pI range (3.4--6.4), whereas IgM spectrotypes are not (4.3--8.8).

Acrylamides↗
PubMed1978

The effect of test taking on acceptance of bogus personality statements.

Ss received either positively or negatively toned feedback after taking a projective test. Other Ss merely received the feedback statements without taking the test. All Ss rated the feedback statements individually and as a unit as to how well they described their personality and the personality of people in general. Feedback as a unit was more acceptable when (a) the test was taken, and (b) when positively toned feedback was received. Collapsing across feedback conditions, personal acceptability was higher for those who took the test than for those who did not take the test. The method allowed for analysis of individual items and thereby provided an additional measure of acceptability than simply using the overall acceptability score.

Adolescent↗
PubMed1976

Rate-dependent effect of amphetamine in rats: extension to between-subjects effect.

Following either variable-interval or fixed-interval training. 20 rats received both 0.5 and 2.0 mg/kg of amphetamine. For both schedules, amphetamine decrease response rates of high-rate subjects and increased those of low-rate subjects. Within-subject analysis of fixed-interval rates revealed the same rate-dependent effect. It is suggested that the between-subject and within-subject effects may have the same basis.

Animals↗
PubMed1976

Effects of dianabol and high-intensity sprint training on body composition of rats.

The effects on body composition and organ weights of anabolic steroid administration and of high-intensity sprint running, separately and in combination, were studied in young adult male rats. Dianabol (methandrostenolone) 1 mg/day for 8 weeks had no significant effects on muscle weight or lean body mass in either the trained or the sedentary animals. The program of sprint training resulted in a lower body weight, a lesser percentage of body fat (Runners, 8.5%, vs. sedentary, 13.5% P less than 0.01) and a greater relative lean body mass (runners, 91.5% vs. sedentry, 86.5%, P less than 0.01). We conclude from these results that (a) normal androgen levels in young, healthy male animals are sufficiently high so that the addition of a large dose of anabolic steroid does not result in stimulation of additional muscle growth, and (b) the changes in body composition induced by high-intensity, short-duration sprint training are qualitatively similar to those seen with endurance exercise training.

Adrenal Glands↗
PubMed1975

Enzymic synthesis of steroid sulphates. XI. Study of the oestrogen binding site of oestrogen sulphotransferase by affinity labelling with 4-mercuri-17beta-oestradiol.

Oistrogen sulphotransferase (3"-phosphoadenylylsulphate: oestrone sulphotransferase, EC 2.8.2.4) contains asingle sulphydryl group thought to be at, or near, the oestrogen-binding site. 4-mercuri-17beta-oestradiol, the activity of the enzyme decreased with increasing concentration of the oestrogen derivative. However, some 40% of the activity remained when all the sulphydryl had reacted to form mercaptide. Formation of mercaptide was only marginally decreased in the presence of the substrate 17beta-oestradiol. Other steroids, such as 11-deoxycorticosterone and testosterone, which are non-substrates for the enzyme, were more effective than 17beta-oestradiol in inhibiting mercaptide formation. Bovine serum albumin also reacted with 4-mercure-17beta-oestradiol and the effects of various steroids on mercaptide formation by the affinity label closely paralleled those found for the enzyme. 2t is concluded that the single sulphydryl group in the enzyme is not directly involved in the binding of oestrogen at the active site but is perhaps in closer proximity to a second site capable of binding certain non-substrate steroids.

Animals↗