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Biomedical subjects

M O'Brien

Publications and source records attributed to M O'Brien.

At least 235 records · Page 13Linked to original sources
PubMed1988

Gastrointestinal sarcoidosis resembling Crohn's disease.

We describe a patient with disseminated sarcoidosis, who had granulomatous enterocolitis with radiological narrowing of the terminal ileum, and was presumed to have Crohn's disease. At autopsy, there were numerous sarcoid-like granulomata throughout the mucosa of the large and small bowel, but no transmural inflammation, lymphoid aggregates, or strictures, thus making Crohn's disease unlikely. It is proposed that a granulomatous enterocolitis resembling Crohn's disease can be a manifestation of disseminated sarcoidosis.

Crohn Disease↗
PubMed1988

The site of the tendinous interruption in semitendinosus in man.

Forty six cadaveric lower limbs were examined to define the presence, site and shape of the tendinous interruption in semitendinosus. It was found to be: 1. Present in all limbs studied. 2. Single in all limbs studied. 3. V-shaped with a short lateral limb and a long medial limb measuring one fifth of the total muscle length. 4. Its apex is one third of the total muscle length from the origin of the muscle.

Humans↗
PubMed1987

Recidivism in a cohort of young Australian drinking-drivers.

Four hundred and sixty-three men aged 18-25 years were referred to a counselling programme in 1975-1977, after their first conviction for an alcohol-related traffic offence. Records of the Victoria Police, and those of the Motor Registration Board, were searched for subsequent alcohol-related traffic offences up to February 1984. Those subjects who had left the State of Victoria or had died were identified, and a "survival" curve was constructed where survival implied freedom from reconviction for an alcohol-related traffic offence. By means of Cox's proportional hazards model, the rate ratios of a number of predictor variables of recidivism were calculated; those of significance were the number of drinks per week, social class, and a history of "family troubles with drinking". Reduction of alcohol consumption may be a more appropriate goal in programmes that are concerned with the counselling of young drinking-drivers than is attempted modification of the drinking-driving nexus.

Accidents, Traffic↗
PubMed1987

Antiproliferative effects of suramin on lymphoid cells.

Suramin, a polyanionic drug used in the treatment of Rhodesian and Gambian trypanosomiasis and more recently in the acquired immune deficiency syndrome, is a potent inhibitor of the constitutive mammalian DNA polymerases alpha, beta, and gamma and the lymphoid-specific polymerase terminal deoxynucleotidyl transferase. To define the effect of this inhibition on cell proliferation, we studied the effect of suramin on several cell lines in culture and in mice in vivo. Suramin, at 200 micrograms/ml (which is regularly achieved in the plasma of patients), had no effect on the proliferation of 4 of 5 nonlymphoid cell lines. In contrast, exposure of 10 lymphoid cell lines to 200 micrograms/ml suramin for 4 days caused significant growth inhibition in 8 of these 10 lines. Suramin given i.p. to BALB/cBYJ mice at clinically relevant doses (15-60 mg/kg) caused profound and prolonged thymic atrophy within 5-7 days of drug administration (greater than a 90% weight loss in mice treated with 60 mg/kg). Thymic sections revealed severe cortical loss, prominence of dendritic cells, and vacuolated macrophages. Liver, peripheral blood, spleen, kidney, and total body weights were not affected. The apparent selective lymphocytotoxicity of suramin may represent an important property of this drug. We speculate that this may account for the persistent immune suppression reported in suramin-treated acquired immune deficiency syndrome patients.

Animals↗
PubMed1987

Ovarian myxoma.

The clinical history, light microscopic, electron microscopic, and immunopathologic findings of an ovarian myxoma in a 32-year-old woman are described. We believe this to be only the fourth such case reported.

Adult↗
PubMed1987

Long-term survivors on peritoneal dialysis.

To obtain information about predialysis characteristics and long-term outcome of patients on peritoneal dialysis (PD) for more than 4 years, we reviewed all patients starting PD who performed continuous ambulatory peritoneal dialysis (CAPD) and were at risk for more than 4 years. Sixty-two patients started; 42% were diabetic and 35% over age 60. Three recovered renal function, seven received transplants, and 12 switched to hemodialysis. Nineteen survived more than 4 years (long-term survivors, LTS), eight diabetic and 12 male. Twenty-one died on CAPD in less than 4 years (short-term survivors, STS). In comparison to STS, LTS were younger, with less prior cardiac disease, yet had higher predialysis serum creatinine values and lower hematocrits. LTS were observed for a mean of 65.3 +/- 3 months (48 to 91 months), and STS for a mean of 21 +/- 2 months. When compared to STS, LTS had fewer hospital days, hospital days for peritonitis, and a lower peritonitis rate, although the incidence of Staphylococcus aureus peritonitis was greater in LTS. Cardiovascular and thromboembolic events were less frequent in LTS, but bone fractures were seen more often in the LTS diabetic patients. Weight gain, especially in males, and hernias were noted in both groups. BP improved, and vision was maintained in both groups. Non-PD-related infections causing hospitalization were low in both groups. Improved mean hematocrit and hemoglobin A, values were seen only in LTS. Mean serum cholesterol values increased with time in LTS. This study reveals that potentially high-risk patients such as diabetics and the elderly can have prolonged survival on PD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

A rapid test for chitinase activity that uses 4-methylumbelliferyl-N-acetyl-beta-D-glucosaminide.

A total of 101 strains of bacteria from environmental and clinical sources, most of which were gram negative, were tested for chitobiase activity by using a filter paper spot test with 4-methylumbelliferyl-N-acetyl-beta-D-glucosaminide as the substrate. The results were compared with those obtained by a conventional plate method for chitinase activity by using colloidal chitin as the substrate. There was excellent agreement in the results for both methods. The filter paper spot test with 4-methylumbelliferyl-N-acetyl-beta-D-glucosaminide has the advantages of being rapid, simple to perform, and inexpensive. This method should be adaptable to a wider range of microorganisms, particularly those with unusual growth requirements.

Acetylglucosamine↗
PubMed1987

The stability of visual habituation during the first year of life.

The short-term reliability and long-term stability of visual habituation and dishabituation in infancy were assessed in a sample of 186 infants from 4 age groups (3-, 4-, 7-, and 9-month-olds) seen for 2 within-age sessions and in a sample of 69 infants seen longitudinally at 3, 4, 7, and 9 months of age. Moderate week-to-week reliability (r's = .30-.50) was observed for duration-based and magnitude of habituation variables at all ages, although better reliability was evident at 4 and 9 months than at 3 and 7 months. In most cases, the reliability of habituation magnitude measures was attributable to the reliability of the peak fixation alone. Data from the longitudinal sample suggested that only the duration of peak fixation was consistently stable across the ages tested, although stability for several measures emerged across the 7-9-month testing. No consistent reliability or stability emerged for the presence or magnitude of dishabituation in either sample.

Age Factors↗
PubMed1986

Delay in the diagnosis of pediatric brain tumors.

The interval from the onset of symptoms to the diagnosis in 79 children with primary brain tumors was compared with that in 45 children with Wilms' tumor and 123 children with acute leukemia. The patients with brain tumors had a significant delay from symptom onset to diagnosis. Only 38% of primary brain tumors were diagnosed within the first month after the onset of symptoms. In contrast, 84% of Wilms' tumors and 80% of cases of acute leukemia were diagnosed within one month of the onset of symptoms. Early detection of brain tumors is important as it may have a significant bearing on clinical outcome.

Acute Disease↗
PubMed1986

The morphological spectrum of T-prolymphocytic leukaemia.

The morphology of the cells from 29 cases of T-prolymphocytic leukaemia (T-PLL) was studied by light (LM) and transmission electron microscopy (TEM) and was compared with that of 33 B-cell PLL. The membrane phenotype of T-PLL cells was T4+, T8- in two-thirds of the cases, others being T4- T8+ or T4+ T8+. Two morphological types of T-PLL were defined according to the nuclear features: regular (55% of cases) and irregular (45% of cases). T-PLL cells with a regular, round or oval, nuclear outline resembled B-PLL cells but had less abundant cytoplasm and a higher nucleo-cytoplasmic ratio. Irregular T-prolymphocytes displayed a distinct convoluted nucleus. A 'small-cell' variant of T-PLL was recognized by TEM in six cases in which the diagnosis was uncertain by LM. A characteristic of all types of T-prolymphocytes by LM was the presence of a deep basophilic cytoplasm which by TEM corresponded to clusters of ribosomes and endoplasmic reticulum. No differences in clinico-haematological features or membrane markers were apparent between the morphological types of T-PLL, although it was noted that the three T4- T8+ cases had irregular cells and four of the small cell variant were T3- T4+. TEM permits a more precise assessment of the cytoplasmic organelles and nucleolus than LM analysis and facilitates the distinction between T-PLL and other leukaemias with a mature T-cell phenotype, namely adult T-cell leukaemia/lymphoma. Sezary syndrome and T-chronic lymphocytic leukaemia.

Aged↗
PubMed1986

Comparison of proteins involved in chondroitin sulfate utilization by three colonic Bacteroides species.

Three species of colonic bacteria can ferment the mucopolysaccharide chondroitin sulfate: Bacteroides ovatus, Bacteroides sp. strain 3452A (an unnamed DNA homology group), and B. thetaiotaomicron. Proteins associated with the utilization of chondroitin sulfate by B. thetaiotaomicron have been characterized previously. In this report we compare chondroitin lyases and chondroitin sulfate-associated outer membrane polypeptides of B. ovatus and Bacteroides sp. strain 3452A with those of B. thetaiotaomicron. All three species produce two soluble cell-associated chondroitin lyases, chondroitin lyase I and II. Purified enzymes from the three species have similar pH optima, Km values, and molecular weights. However, peptide mapping experiments show that the chondroitin lyases from B. ovatus and Bacteroides sp. strain 3452A are not identical to those of B. thetaiotaomicron. A cloned gene that codes for the chondroitin lyase II from B. thetaiotaomicron hybridized on a Southern blot with DNA from B. ovatus or Bacteroides sp. strain 3452A only when low-stringency conditions were used. Antibody to chondroitin lyase II from B. thetaiotaomicron did not cross-react with chondroitin lyase II from B. ovatus or Bacteroides sp. strain 3452A. Chondroitin lyase activity in all three species was inducible by chondroitin sulfate. B. ovatus and Bacteroides sp. strain 3452A, like B. thetaiotaomicron, have outer membrane polypeptides that appear to be regulated by chondroitin sulfate, but the chondroitin sulfate-associated outer membrane polypeptides differ in molecular weight. Despite these differences, the ability of intact bacteria to utilize chondroitin sulfate, as indicated by growth yields in carbohydrate-limited continuous culture and the rate at which the chondroitin lyases were induced, was the same for all three species.

Bacterial Outer Membrane Proteins↗
PubMed1986

Colonization of the gut of the blue crab (Callinectes sapidus) by Vibrio cholerae.

Attachment of Vibrio cholerae to the mucosal surface of the intestine is considered to be an important virulence characteristic. Vibrio cholerae, an autochthonous member of brackish water and estuarine bacterial communities, also attaches to crustacea, a significant factor in multiplication and survival of V. cholerae in nature. The ability of V. cholerae to attach to the gut wall of the blue crab (Callinectes sapidus) was examined, and attachment was observed only in the hindgut and not the midgut of crabs, confirming a requirement for chitin in the attachment of V. cholerae to invertebrate and zooplankton surfaces. The new finding of attachment of V. cholerae to the hindgut of crabs may be correlated with the epidemiology and transmission of cholera in the aquatic environment. The crab model may also prove useful in elucidating the mechanism(s) of ion transport in crustacea.

Animals↗