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Biomedical subjects

M Gardner

Publications and source records attributed to M Gardner.

At least 109 records · Page 6Linked to original sources

The roles of self-esteem and self-consciousness in the Wortman-Brehm model of reactance and learned helplessness.

The present experiments were designed to study the conditions under which failure would enhance or inhibit subsequent task performance. Based on the theory of Wortman and Brehm (1975), it was expected that small amounts of failure would produce reactance (manifested by improved performance at a subsequent task), whereas large amounts would lead to learned helplessness (i.e., impaired later performance). It was further expected that individual differences in self-esteem and private self-consciousness would serve as moderator variables for the above effects. In Experiment 1, subjects were exposed to either a small amount of failure or no failure before working on an anagrams task. As predicted, subjects high in self-consciousness, who have shown greater reactance arousal in attitude change studies, performed better on the anagrams task than subjects low in self-consciousness in the small-failure condition, but not in the no-failure condition. Further analyses revealed that this Self-Consciousness X Small Failure interaction was attributable to the performance data of the low, but not the high self-esteem subjects. Experiment 2 was designed to replicate and extend these results. Subjects were pretreated with either a small amount of failure, an extended amount of failure, or no failure before working on the anagrams task. A significant Self-Esteem X Helplessness Training interaction emerged. Relative to the no-failure condition, in which the two self-esteem groups did not differ, low self-esteem participants (low SEs) performed marginally better than did high self-esteem individuals (high SEs) in the small-failure condition but significantly worse than high SEs in the extended-failure condition. The effect of private self-consciousness was considerably weaker in this study, possibly because the sample included few low SEs (who are especially influenced by self-focused attention) who were also relatively low in self-consciousness. Questionnaire data from Experiment 2 were consistent with the notion that enhanced performance reflected reactance, whereas impaired performance signified helplessness.

Arousal↗

Digital replantation distal to the proximal interphalangeal joint.

Microvascular replantation of digits distal to the proximal interphalangeal joint were reviewed in 24 digits in 18 patients. Of the 24 digits studied, five were seen in patients who had a single digit amputated and replanted, 10 were seen in patients who had multiple distal digital amputations and replantations, and eight were seen in patients who had other proximal digital replantations or other associated hand injuries in addition to the distal replantations. Survival rate in this study was 96%, and the mean active range of motion at the proximal interphalangeal joint was 95 degrees with 8.9 degrees active motion at the distal interphalangeal joint. Two-point discrimination averaged 11 mm, and all patients had some cold intolerance. The nine students in this study required a mean 1.7 months to return to school; nine patients were workers and required a mean of 5.1 months to return to work. Acceptance for the procedures was overwhelmingly good. Replantation of an amputated digit distal to the proximal interphalangeal joint in selected cases can be a worthwhile procedure.

Adolescent↗

Dietary fat affects immune response, production of antiviral factors, and immune complex disease in NZB/NZW mice.

Autoimmune-prone (NZB x NZW)F1 (B/W) mice fed three nearly isocaloric diets with varied fat content showed a marked difference in their spontaneous development of immune complex disease and their immune response. Those animals received the diets high in either unsaturated or saturated fats had more severe immune complex nephritis and died earlier than mice on the low-fat diet. Endogenous production of the mouse xenotropic virus was unaffected by dietary fats, but the serum lipoproteins associated with antiviral activity were increased to levels as high as 1:600,000 in the B/W mice on the high-fat diets. These lipoproteins may be partially responsible for the decreased mitogenic response of spleen cells from mice fed the two high-fat diets. The mice receiving a diet high in saturated fats produced substantially higher titers of natural thymocytotoxic autoantibody, an IgM class of antibody, than did the mice maintained either on the high-unsaturated-fat or low-fat diet. In contrast, the mice receiving the diet high in unsaturated fats made significantly greater levels of antibodies to double-stranded DNA, an IgG, than did the mice kept on the two other diets. These results suggest that the type of fat in the diet could affect the serum level of different immunoglobulin classes. The data provide further evidence that the amount of dietary lipids alone can influence cellular and humoral immune responses and the spontaneous development of immune complex disease.

Animals↗

Molecular cloning of the endogenous rat C-type helper virus DNA sequence: structural organization and functional analysis of some restricted DNA fragments.

Recently, we have identified and purified the integrated and proviral DNA sequences specific for two endogenous rat type C leukaemia helper viruses: WR-RaLV which originated from a fibrosarcoma induced in a feral rat and RHHV from the cell line HTC-H1 which originated from a Buffalo rat hepatoma. The rat leukaemia helper virus DNA sequences have previously been shown to be 8.4 to 8.8 kilobases (kb) in size. In this communication, we report the molecular cloning of the 8.8 kb DNA of RHHV by ligation at the BamHI site of the vector pBR322, cultured in an Escherichia coli RR1 host. After screening 5750 clones for ampicillin resistance and tetracycline sensitivity and testing by colony hybridization using 32P-labelled RHHV cDNA, four clones were isolated, two of which carried the total 8.8 kb DNA. A detailed restriction endonuclease map of the cloned RHHV DNA was deduced by sequential digestions of either 3'- or 5'-labelled DNA. Of the 14 restriction enzymes tested, EcoRI, BamHI, PstI, KpnI, TaqI, PvuII and SmaI gave informative cleavage patterns. At least two copies of long terminal repeated sequences (LTR) flanking the 3' and 5' termini of the proviral DNA were identified by TaqI and PstI cleavages. LTR in the rat endogenous leukaemia helper virus DNA measured 780 +/- 20 nucleotides in length. The genetic information encoded by the cloned DNA was also analysed by hybridization selection of RHHV mRNA, which was then used in cell-free protein synthesis in a rabbit reticulocyte lysate system. Essentially all major RaLV-specific proteins precipitable by anti-RaLV serum were synthesized in vitro, confirming that the RHHV genomic DNA was successfully cloned with little fidelity loss or scrambling of the genetic information.

Animals↗

Long oesophageal myotomy for diffuse spasm of the oesophagus.

The symptoms of chest pain and dysphagia together with the typical radiological features of non-peristaltic segmental oesophageal contractions allowed the diagnosis of diffuse oesophageal spasm to be made in ten patients at The Prince Charles Hospital over the last six years. Eight patients have undergone long oesophageal myotomy with sparing of the lower oesophageal sphincter. All patients had immediate postoperative relief of symptoms, with postoperative cine radiographic examination in all patients demonstrating an inert oesophagus with adequate drainage and no gastro-oesophageal reflux. Two patients subsequently developed progressive dysphagia, one requiring a modified Heller's procedure. Because of the good result in six patients, sparing of the lower oesophageal sphincter with long oesophageal myotomy is recommended.

Adult↗

Development of a mouse mammary tumor virus-negative mouse strain: a new system for the study of mammary carcinogenesis.

All inbred strains of mice transmit one or more copies of mouse mammary tumor virus (MMTV) DNA integrated as proviral sequences. This complicates efforts to define viral-induced mammary carcinogenesis. Here we report the use of surgical nonlethal splenectomy in tissue typing mice and the development of an MMTV-negative mouse strain. The MMTV-negative strain allows study of the involvement of non-MMTV genes in mammary carcinogenesis. In addition, it can be used as a sterile background into which MMTV variants can be introduced. Through the techniques described here, mice containing single MMTV loci or specific combinations can be specially chosen and rapidly developed. In this manner, the oncogenecity of particular MMTV variants may be assessed.

Animals↗

Clinical and pharmacokinetic factors affecting response to phenelzine.

Sixty patients, 30 with depressive neurosis, 15 with anxiety neurosis and 15 with phobic anxiety states, were treated with the monoamine oxidase inhibitor, phenelzine, in two different dosage schedules for four weeks. All patients received an initial dose of 15 mg daily, increasing to 30 mg daily between the third and seventh day, but subsequently, using double-blind procedure, one group tooke the commonly prescribed dose of 45 mg daily and the other took 90 mg daily. Acetylator status was independently determined before the start of treatment. Each diagnostic group showed a similar response to treatment, but patients taking the higher dose improved significantly more than those taking normal dosage, and the rate of improvement, measured by weekly self-ratings, was also more rapid with higher dosage. Acetylator status did not affect clinical response. The results suggest that dosage is more important in determining clinical response to phenelzine in neurotic disorder than specific diagnosis or acetylator status.

Anxiety Disorders↗

Dietary fibre.

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Cellulose↗

Arrays of hemispheric surface projections on Chlamydia psittaci and Chlamydia trachomatis observed by scanning electron microscopy.

Scanning microscopy of two strains of Chlamydia psittaci and four strains of Chlamydia trachomatis representative of the wide diversity in origin and behavior of members of the genus revealed patches of regular arrays of hemispheric projections on the surfaces of elementary bodies of all six strains. These distinctive and perhaps unique surface structure are probably present in all populations of chlamydiae.

Cell Membrane↗

Enhanced biotransformation of theophylline in marihuana and tobacco smokers.

Single oral doses of theophylline were administered to 7 chronic marihuana smokers, to 7 chronic users of both marihuana and tobacco, and to 43 appropriate control subjects. Theophylline was cleared from the blood more rapidly in both marihuana and tobacco smokers with a mean increase in total clearance from 52 ml/kg/hr in nonsmokers to 74 ml/kg/hr in subjects who smoked either material alone. There was an additive increase in clearance to 93 ml/kg/hr in those who smoked both substances. Concern over enhanced metabolism of other drugs is probably warranted in tobacco and cannabis smokers.

Adult↗

Coronary artery bypass occlusion second to postcardiotomy syndrome.

Postcardiotomy syndrome following coronary vein bypass procedures may cause graft occlusion as a result of the associated myxedematous hyperemic inflammation that later forms dense obliterative fibrosis. Variability of symptoms and onset make early recognition of postcardiotomy syndrome difficult. However, the presence of the classic triad of fever, chest pain, and pleuroericardial reactions along with leukocytosis and elevated sedimentation rate should suggest the diagnosis. Early recognition and prompt institution of steroid therapy offer relief of symptoms and regression of inflammation and probably reduce the incidence of graft occlusion. From early experience with 14 patients who developed postcardiotomy syndrome and received only symptomatic treatment, 12 developed graft occlusion, whereas in 31 subsequent patients with this syndrome who were treated with steroids, only 5 demonstrated graft occlusion.

Adult↗