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Biomedical subjects

B J Miller

Publications and source records attributed to B J Miller.

At least 55 records · Page 3Linked to original sources
PubMed1993

Retention of surgical knowledge base by senior medical students.

The medical course at the University of Queensland is 6 years in length. After studies in basic sciences, the fourth year consists of systematic pathology, clinico-pathological correlation and the learning of clinical methods. During the fifth year the core surgical knowledge base is taught. The sixth year is spent in clinical ward work aimed at problem-orientated consolidation of knowledge and skills, and the learning of applied therapeutics. We studied whether the surgical knowledge base taught to our fifth year students was retained a year later by the same students in their final year. A standardized post-test examination which had been presented to the students during their fifth year in 1990 was again presented to them during their sixth year in 1991. We found that the surgical knowledge base of this group of students remained the same in their final year as it had been in their penultimate year. We suggest that to continue testing core surgical knowledge once it has proven satisfactory is not productive. These students should progress to further clinical studies aimed at improving their problem solving ability.

Educational Measurement↗
PubMed1993

Do medical students remember multiple choice questions?

The values of pre-testing senior medical students at the start of their surgical terms are the perception that they acquire of the scope of the subject and the extra practice they gain in the technique of sitting multiple choice question (MCQ) exams. The purpose of this study was to determine whether MCQ in a pre-test that were repeated in a post-test were answered more accurately than questions that had not been repeated. For the past 3 years at the University of Queensland, fifth year medical students have been voluntarily sitting pre- and post-tests in each of the four surgical terms. Each examination consisted of 60 clinically oriented surgical questions of a difficulty appropriate for senior medical students. A total of 404 students did both the pre- and post-tests during 1990 and 1991. The two examinations were carefully chosen for comparability. Of the 60 questions in each examination, 30 were repeated in the post-test and 30 were fresh questions in the post-test. The pre- and post-tests were reversed for the second of the two years to increase consistency. There was a general improvement in the standard of results from the pre-test to the post-test. There was also a small improvement for the repeated questions compared to the non-repeated questions (P < 0.0001). The authors conclude that the marked improvement of the post-test compared to the pre-test is mostly attributable to the students increasing their knowledge base through learning during their surgical term.(ABSTRACT TRUNCATED AT 250 WORDS)

Educational Measurement↗
PubMed1993

The resource implications of severe necrotizing pancreatitis treated by necrosectomy.

This study reviews the resource utilization of patients admitted to the Intensive Care Unit (ICU) with severe necrotizing pancreatitis treated by early necrosectomy. For 21 patients there was a total of 221 abdominal operations, 2365 hospital days, 565 ICU days and 1185 days of parenteral nutrition. The mortality rate was 43%. The treatment for patients with necrotizing pancreatitis is 10 times more resource intense than other admissions to the ICU. The implications of necrotizing pancreatitis treated by necosectomy in the context of a Diagnosis-Related Groups Prospective Payment model of hospital funding are discussed.

Adult↗
PubMed1993

Iron status of female runners.

This study was designed to observe iron status and prevalence of iron deficient conditions in adult female habitual runners (n = 111) and inactive females of comparable age (n = 65). The runners were significantly lower (p < .05) than the reference group in mean serum ferritin (SF), total iron binding capacity, and red blood cell count, but significantly higher (p < .05) in mean corpuscular hemoglobin. The groups did not differ significantly in hemoglobin concentration, hematocrit, serum iron, percent saturation of transferrin, or red cell protoporphyrin. Chi square analysis indicated that iron depletion (SF < 20 ng.ml-1) was significantly more prevalent (p < .005) in the runners than in the controls. Anemia was extremely rare in both groups. A multiple regression analysis revealed significant negative associations between serum ferritin and coffee/tea intake (p < .001) and running activity (p < .05). These results indicate that habitual runners, as compared with inactive women, are at increased risk for iron deficient states but that full-blown anemia is a rare consequence of this deficient iron status.

Adult↗
PubMed1993

The essentiality of folate for the maintenance of deoxynucleotide precursor pools, DNA synthesis, and cell cycle progression in PHA-stimulated lymphocytes.

The fidelity and progression of DNA synthesis is critically dependent on the correct balance and availability of the deoxynucleoside triphosphate (dNTP) precursors for the polymerases involved in DNA replication and repair. Because folate-derived one-carbon groups are essential for the de novo synthesis of both purines and pyrimidines, the purpose of this study was to determine the effect of folate deprivation on deoxynucleotide pool levels and cell cycle progression. Primary cultures of phytohemagglutin (PHA)-stimulated splenocytes were used as the cellular model. T-cells and macrophages were purified from spleen cell suspensions obtained from F344 rats and recombined in culture. The cells were harvested after a 66-hr incubation with PHA and analyzed for nucleotide levels by reverse-phase HPLC with diode array detection. The proportion of cells in the different phases of the cell cycle was determined by bivariate flow cytometric measurement of bromodeoxyuridine (BrdU) incorporation and DNA content (propidium iodide staining). PHA-stimulated T-cells cultured in medium lacking folate and methionine manifested significant decreases in the deoxynucleotides dCTP, dTMP, dGTP, and dATP relative to cells cultured in complete medium. The reduction in dNTP pools was associated with a decrease in the corresponding ribonucleotide pools. Flow cytometric analysis revealed a 2-fold increase in S and G2/mitosis (G2/M) DNA content in PHA-stimulated cells cultured in the medium lacking folate and methionine, which suggests a delay in cell cycle progression. These alterations in DNA content were accompanied by a 5-fold decrease in BrdU incorporation relative to PHA-stimulated cells cultured in complete medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Bochdalek hernia with hemorrhage in an adult.

Life-threatening herniation of intra-abdominal viscera through a patent Bochdalek foramen is well recognized in neonates. Persistent foramina, leading to clinical problems in adult life, are very rare. In the case of the 17-year-old girl described in this paper, two-thirds of the stomach had inverted and passed into the left side of the chest as had the splenic flexure of the colon and most of the greater omentum. There was 500 mL of blood free in the peritoneal cavity and 1200 mL in the left pleural cavity, with no hernial sac. The defect measured 5 cm in diameter. It was repaired primarily after reduction of the viscera. Prompt operative intervention is recommended in such cases to prevent strangulation and bleeding from engorged viscera.

Adolescent↗
PubMed1993

Ozone depletion: causes, potential effects and remedies.

The ozone layer functions as a protective screen, filtering out most of the sun's harmful ultraviolet (UV) rays. This protective layer is located in the stratosphere between 15km and 35km above the earth's surface. Ozone is actually a form of oxygen. In the lower atmosphere, oxygen atoms commonly bond with each other in pairs. This molecule, abbreviated as O2, is the form of oxygen we need to breathe. Ozone is a more unstable and uncommon molecule made up of 3 oxygen atoms and is abbreviated O3.

Aerosols↗
PubMed1992

Autoimmune syndromes in major histocompatibility complex (MHC) congenic strains of nonobese diabetic (NOD) mice. The NOD MHC is dominant for insulitis and cyclophosphamide-induced diabetes.

The development of autoimmune diabetes in the nonobese diabetic (NOD) mouse is controlled by multiple genes. At least one diabetogenic gene is linked to the major histocompatibility complex (MHC) of the NOD and is most likely represented by the two genes encoding the alpha and beta chains of the unique NOD class II molecule. Three other diabetogenic loci have recently been identified in the NOD mouse and are located on chromosomes 1, 3, and 11. In addition to the autoimmune diabetes which is caused by destruction of the insulin-producing beta cells in the pancreas, other manifestations of autoimmunity are seen in the NOD mouse. These include mononuclear cell inflammation of the submandibular and lacrimal glands, as well as the presence of circulating autoantibodies. To determine the effect of the non-MHC diabetogenic genes on the development of autoimmunity, we constructed the NOD.B10-H-2b (NOD.H-2b) strain, which possesses the non-MHC diabetogenic genes from the NOD mouse, but derives its MHC from the C57BL/10 (B10) strain. The NOD.H-2b strain does not develop insulitis, cyclophosphamide-induced diabetes, or spontaneous diabetes. It does, however, develop extensive lymphocytic infiltrates in the pancreas and the submandibular glands that are primarily composed of Thy 1.2+ T cells and B220+ B cells. In addition, autoantibodies are present in NOD.H-2b mice which recognize the "polar antigen" on the insulin-secreting rat tumor line RINm38. These observations demonstrate that the non-MHC genes in the NOD strain, in the absence of the NOD MHC, significantly contribute to the development of autoimmunity. The contribution of a single dose of the NOD MHC to autoimmunity was assessed with a (NOD x NOD.H-2b)F1 cross. Although only approximately 3% of F1 females developed spontaneous diabetes, approximately 50% of both female and male F1 mice developed insulitis, and 25% of females and 17% of males became diabetic after treatment with cyclophosphamide. These data demonstrate that the MHC-linked diabetogenic genes of the NOD mouse are dominant with decreasing levels of penetrance for the following phenotypes: insulitis greater than cyclophosphamide-induced diabetes greater than spontaneous diabetes.

Animals↗
PubMed1992

Bleeding tendency, platelet function, and pharmacokinetics of ibuprofen and zidovudine in HIV(+) hemophilic men.

The use of ibuprofen (IBP) in hemophilic men for chronic hemophilic arthropathy is associated with transient coagulation abnormalities, but usually does not cause bleeding symptoms. However, when hemophilic men are treated with ibuprofen while also receiving zidovudine (ZDV), excess bleeding has occurred in some. In order to evaluate platelet function and pharmacokinetics of combination IBP and ZDV, we measured platelet aggregation, platelet adhesive index, bleeding time, and IBP and ZDV drug levels by high performance liquid chromatography on five patients receiving chronic oral IBP, 400 mg every 6 hr, and on ten patients receiving both IBP and ZDV, 100 or 200 mg every 4 hr five times daily. Samples were obtained at baseline (ZDV alone), acutely (IBP+ZDV acutely), and chronically (2 weeks on IBP and ZDV). Abnormal platelet aggregation with arachidonic acid occurred in four of five (80%) of those receiving IBP alone and in 7 of 10 (70%) at baseline, 9 of 10 (90%) at acute, and 8 of 10 (80%) at chronic IBP and ZDV treatment, most commonly at 2 hr following dosing, when peak IBP levels occurred, and persisting 4 hr in those on chronic dosing. Half or more of those on combination IBP+ZDV showed a lowered platelet adhesive index and/or prolonged bleeding time. Excess bleeding symptoms occurred in three on chronic combination IBP+ZDV, two with increased frequency of spontaneous hemorrhages, and one with prolonged traumatic bleeding. Bleeding tendency was unrelated to the degree of platelet function abnormality, to peak drug levels of IBP or ZDV, or degree of liver function abnormality (SGPT). The clearance of IBP alone and ZDV alone were not different from the clearance of combination IBP and ZDV. Caution is urged regarding potential enhanced bleeding tendency in hemophiliacs receiving both IBP and ZDV in combination.

Acute Disease↗
PubMed1992

Alterations in nucleotide pools in rats fed diets deficient in choline, methionine and/or folic acid.

The fidelity of DNA synthesis is critically dependent on the correct balance and availability of the deoxynucleoside triphosphate (dNTP) precursors for the polymerases involved in replication and repair. Since folate-derived one-carbon groups are essential for the de novo synthesis of both purines and pyrimidines, the purpose of the present investigation was to determine whether diet-induced depletion of folates would alter intracellular dNTP pools. Fischer 344 rats were fed one of four semi-purified diets for a period of 8 weeks: (i) supplemented control; (ii) deficient in folic acid; (iii) deficient in methionine and choline; and (iv) deficient in methionine, choline and folic acid. In contrast to natural diets, semi-purified diets are nucleotide-free and consequently lack substrates for salvage pathway synthesis. This omission may place unusual stress on folate-dependent de novo nucleotide synthesis especially under conditions of dietary methyl-donor deficiency. Reversed-phase HPLC analysis of dNTP in spleen cell extracts indicated that both the thymidylate monophosphate and thymidylate triphosphate pools were decreased in spleen cells from the deficient rats consistent with a decrease in folate-dependent de novo synthesis. In addition, purine biosynthesis appeared to be negatively affect by methyl-donor deficiency as evidenced by a reduction in dGTP and dATP pools. These data indicate that deoxynucleotide pool imbalance, well known to produce cytogenetic and mutagenic events in vitro, can also be induced in this in vivo model of diet-induced carcinogenesis.

Animals↗
PubMed1992

Ileosigmoid knotting: a case report and review.

Ileosigmoid knotting, or compound volvulus, has not been reported previously in Australia. A 41 year old woman of Anglo-Saxon origin presented with a short history of extreme abdominal pain that was out of proportion to her physical findings. At operation it was found that her entire ileum was tightly knotted around the redundant, twisted sigmoid colon. Both closed loops were gangrenous and it was impossible to unravel the bowel. She recovered uneventfully following resection and primary anastomosis of both portions of the intestine. Most patients with this uncommon condition have been reported from Finland and eastern Africa. An arrangement of the small bowel and sigmoid colon on long, narrow mesenteries would appear to be a prerequisite. The brevity of the history and the severity of the abdominal pain call for early laparotomy. Prolonged attempts to untie the knot are dangerous. It is safer to divide the ileum at the knot and resect it in order to release the sigmoid colon. Primary anastomosis is feasible where the history is short and the uninvolved intestine is clean and collapsed.

Abdominal Pain↗
PubMed1991

Human monoclonal antibodies demonstrate polyreactivity for histones and the cytoskeleton.

Systemic lupus erythematosus (SLE) and other autoimmune diseases are characterized by immune responses to intracellular, highly conserved antigens such as DNA and histone. In this study, peripheral blood lymphocytes (PBL) from a patient with histone autoantibodies were used to prepare IgM human-human hybridoma cell lines. Indirect immunofluorescence (IIF) was used to identify monoclonal antibodies that bound to cytoskeletal and other cytoplasmic constituents. These supernatants did not bind double-stranded or single-stranded DNA. However, immunoblotting revealed that 7/20 hybridomas selected for their binding to cytoskeletal components produced antibodies that also bound mammalian and avian histones. When peptide fragments of histone were used in immunoblotting experiments, it was found that the monoclonal antibodies bound to the carboxyl terminus of H1, a region previously shown to bind autoantibodies from sera of patients with SLE and drug-induced lupus (DIL). When the amino acid sequences of histones and cytoskeletal components were compared using the Swiss-Prot protein data bank, it was confirmed that there are eight regions of similarity. While the significance of polyreactive human monoclonal antibodies to cytoskeletal components and histones is not understood at present, it is possible that the human histone antibodies represent polyreactive antibodies that arise through the mechanism of molecular mimicry.

Amino Acid Sequence↗
PubMed1991

Suicidal tendency and multiple sclerosis.

This article examines the relationship between various physiological, psychological, and social variables and suicidal tendency among people with multiple sclerosis. In 1986, a sample of 147 respondents with multiple sclerosis was obtained. The authors studied the absence of social support systems as an important predictor of suicidal tendency in people with multiple sclerosis. Multiple regression is used to assess the independent effects of predictors. Findings suggest family support, hopelessness, and self-perceived religiosity as predictors of suicidal tendency.

Adult↗
PubMed1991

Pre- and post-testing of students in surgery: do medical rotations help?

A prospective multiple choice question (MCQ) study developed to pre- and post-test fifth year medical students at the University of Queensland, was undertaken during 1990. We investigated whether there was a significant gain in their surgical knowledge base resulting from non-surgical rotations during the same year. We have previously reported a retrospective study suggesting that there was such a gain. Comparable clinical surgical pre- and post-tests were adapted from a fresh question bank, and were presented prospectively to four groups of fifth year medical students at the beginning and end of each 7 week General Surgical term. In contrast to our retrospective study, we found there was no significant increment in surgical knowledge using non-parametric Notched Box and Whisker Plot analysis of data. We conclude that this is either because students are compartmentalizing their factual knowledge base between one speciality and the next, or that indeed there is no benefit to Surgical knowledge base from prior non-surgical rotations. Assuming the former, a combined Medical and Surgical Objective Structured Clinical Examination (OSCE) at the end of the fourth year could serve to broaden the student's horizons and reduce factual dissociation during the fifth year.

Clinical Clerkship↗
PubMed1991

Importance of eccentric actions in performance adaptations to resistance training.

The inability of the exercises presently used during space-flight to maintain muscle strength and mass may reflect the absence of eccentric (ecc) muscle actions. This study examined the importance of ecc actions in performance adaptations to resistance training. Middle-aged males performed 4-5 sets of 6-12 repetitions (rep) per set of the leg press and leg extension exercises 2 d each week for 19 weeks. Group CON/ECC (n = 9) performed each rep with concentric (con) and ecc actions, group CON (n = 8) with only con actions. Group CON/CON (n = 10) performed twice as many sets with only con actions. The resistance per set was selected to induce failure within the prescribed number of rep. Eight subjects did not train and served as controls. The increase in the three rep maximum (3RM) after training, in general, showed a hierarchy such that CON/ECC greater than CON/CON greater than CON. The differences (p less than 0.05) were: leg press 3RM with con and ecc actions, CON/ECC greater than CON/CON greater than CON (26 greater than 15 greater than 8%); leg press 3RM with only con actions, CON/ECC or CON/CON greater than CON (22 or 18 greater than 14%); and leg extension 3RM with con and ecc actions, CON/ECC greater than CON (29 greater than 16%). These differences (p less than 0.05) were still evident after 1 month of de-training. The results indicate that omission of ecc actions from resistance training compromises increases in strength, probably because intensity is not optimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1990

Incarcerated sigmoid bottle.

A 67-year-old man presented to Casualty approximately 12 hours after the insertion of a bottle into his rectum. An attempt was made to deliver the bottle through the rectum but because of perirectal oedema and a coat-hanger wire around the internal end of the bottle, this proved impossible. Laparotomy was performed and the bottle was removed through a longitudinal colotomy.

Aged↗
PubMed1990

Surgical knowledge base augmentation by medical rotations: does it happen?

A study of 4 groups of fifth year medical students taking Surgery during the 4 terms of 1989 at the University of Queensland was undertaken to determine whether there was assimilation of factual material relevant to the surgical knowledge base from the other specialty rotations done during the same year of the course. The records of multiple choice question (MCQ) examination results for the 210 students were retrieved and reviewed. The performance of the same students during their fourth-year rotation in Surgery was checked to make sure that the 4 groups did not already display unusual surgical aptitude or incompetence. The questions were categorized in order to ascertain that the content of all the examinations was similar. The results of students doing Surgery during the first of the 4 terms in 1989 were compared with subsequent groups. The difference between the groups was that those in the first term had not had the benefit of fifth year rotations through Internal Medicine, Psychiatry, General Practice and electives. Subsequent groups had increasing experience in the other specialties. The fourth and final group in the year had undertaken all four of the other rotations before doing Surgery. Significant improvement was found in the performance of each of the subsequent groups of students compared with the first-term group. This implies that there is an escalating accural of factual knowledge related to surgery from the fifth-year courses in Internal Medicine, Child Health and Psychiatry.

Curriculum↗