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Biomedical subjects

M McDermott

Publications and source records attributed to M McDermott.

At least 127 records · Page 7Linked to original sources
PubMed1986

Sites of cleavage of rabbit muscle aldolase by purified cathepsin M from rabbit liver.

Rabbit liver cathepsin M, a sulfhydryl proteinase similar in catalytic properties to cathepsin B, causes a decrease in the activity of rabbit muscle aldolase assayed with fructose 1,6-bisphosphate but not with fructose 1-phosphate. Proteolytic modification of aldolase by cathepsin M is limited to the removal of small peptides from the COOH-terminus, including the COOH-terminal hexapeptide NH2-Ile-Ser-Asn-His-Ala-TyrOH. Correlation of loss of aldolase activity with COOH-terminal modification indicates that only three of the four subunits of muscle aldolase contribute to the catalytic activity of the tetrameric enzyme.

Animals↗
PubMed1986

A multicase family study of rheumatoid arthritis in south west Ireland.

A study of 26 families with multiple cases of RA was conducted in South West Ireland. In 149 relatives examined, 67 cases of RA were identified. An analysis of affected sibling pairs and trios revealed significant linkage between HLA and RA (p less than 0.05). A high frequency of DR4 was observed in probands (80.7 per cent) and affected members (74.6 per cent) compared with controls (18 per cent). An elevated frequency of the haplotypes A2-B44-DR4 (19.2 per cent) and A2-Bw62-DR4 (5.7 per cent) was seen in the affected sample. HLA-Bw62 was at raised frequency in probands (19.2 per cent) compared with controls (9 per cent). The haplotype frequency of A2-B44-DR4 was raised in affected females and A2-Bw62-DR4 in affected males. A low haplotype frequency of A1-B8-DR3 was found in all RA subjects. Disease severity (clinical and radiological criteria) was associated with DR4, but this did not reach statistical significance. A high incidence of extra-articular features of RA was observed, with DR4 occurring in all cases of vasculitis (75 per cent of whom were DR4 homozygous).

Adult↗
PubMed1985

Lung function after exposure to barley dust.

Six men handling barley were followed up over two working days and their flow volume curves were measured every two hours. All experienced falls in ventilatory capacity of up to 800 ml with changes in the shape of the flow volume curve in five men. Five volunteers not previously exposed to barley dust sat in a silo for two hours. Decreases in ventilatory capacity ranging from 200 ml to 800 ml were found, with recovery taking up to 72 hours. All subjects had decreases in flow at 50% vital capacity but little or no change in flow at 75% vital capacity. In three subjects there was a drop in specific conductance that lasted for less than 24 hours. Two subjects were similarly exposed on a second occasion when transfer factor for carbon monoxide was measured in addition to flow volume curves. There was a decrease in transfer factor but no change in transfer factor per unit volume (Kco).

Dust↗
PubMed1985

Influence of testosterone on ventilation and chemosensitivity in male subjects.

There is increasing evidence that men have higher ventilatory responses to chemical stimuli than age-matched women and that certain disorders of respiratory rhythmicity, particularly sleep apnea, occur more commonly in men. Accordingly, we studied the influence of the male hormone, testosterone, on the control of breathing. Twelve hypogonadal males were studied at least 30 (mean +/- SE: 69.7 +/- 8.9) days after discontinuing testosterone replacement and again following hormone administration. In each subject plasma testosterone concentration, metabolic rate [O2 consumption (VO2) and CO2 production (VCO2)], minute ventilation (VE), and chemosensitivity [hypoxic (HVR) and hypercapnic (HCVR) ventilatory responses] were determined on and off hormone replacement. With testosterone administration VO2 increased from 248 +/- 15 to 276 +/- 18 ml/min (P less than 0.05), with VCO2 showing a similar but nonsignificant trend. This was associated with an increase in VE from 8.41 +/- 0.78 to 9.91 +/- 0.75 l/min (P less than 0.05) but no change in PCO2. The HVR, expressed as A, increased 44% with hormone replacement from a value of 122 +/- 23 to 176 +/- 28 (P less than 0.01), whereas the HCVR was minimally affected by testosterone administration. These findings may in part explain the previously described differences between male and female subjects in hypoxic sensitivity.

Adult↗
PubMed1985

A fatal lymphoproliferative disorder with a suppressor T-cell phenotype. Neoplastic, reactive, or both?

We describe the case of a boy who presented with clinical features of lymphadenitis accompanied by a lymphocytic leukemoid reaction of suppressor/cytotoxic T-cell phenotype. Progressive involvement of the bone marrow, liver, and spleen, and subsequently parotid and lacrimal glands, in the disease process, suggested the alternative diagnosis of malignant lymphoma. An initial dramatic response to Prednisolone was not sustained and he died within 8 weeks of the original onset of symptoms. Postmortem examination revealed extensive lymphocytic infiltration in many organs, and a differential diagnosis of lymphoproliferation is considered. The pathogenesis of this disorder is not established; whether it was essentially neoplastic or reactive is unresolved.

Child↗
PubMed1984

Management of acute subdural hematomas from aneurysmal rupture.

Subdural hematomas (SDH) from ruptured aneurysm (RA) are much less common than intracerebral (ICH) hematomas or subarachnoid (SAH) or intraventricular hemorrhage (IVH). With computerized tomography, preoperative diagnosis is now made more often. The authors have collected 18 such cases from a review of 897 cases of RA admitted to eleven medical centers in 1980 and 1981. Nine (50%) of these patients died prior to discharge from hospital. Four (22%) had surgery and died postoperatively and 9 (50%) were operated upon and survived. Thirteen (72%) of the patients showed anisocoria, decreased consciousness and unilateral weakness prior to surgery. Eight (89%) of the fatalities had shown preoperative herniation as opposed to only 5 (56%) of the survivors. The overall incidence of delayed ischemia due to vasospasm was 11% (2 cases). Those who died had greater midline shift and larger SDH on the admission CT scan. Sixteen (89%) of these patients were female. Thirteen (72%) had ruptured aneurysms on the internal carotid artery. All of these hematomas were unilateral and uniformly hyperdense, and the convexity hematomas were crescentic in shape. Seventeen (94%) had evidence of blood in locations other than the subdural space. If the patient is potentially salvageable and has a midline shift, the SDH should probably be evacuated immediately and the aneurysm clipped at the same operation since the development of a tentorial herniation has such an adverse effect on outcome.

Acute Disease↗
PubMed1984

Spontaneous arterial subdural hematoma.

the occurrence of spontaneous arterial subdural hematomas is very rare. We report five patients who presented with sudden severe headache and who developed progressive neurological deficits, two becoming comatose. None had a history of trauma. A diagnosis of subarachnoid hemorrhage was suspected in all patients, but all proved to have subdural hematomas caused by "spontaneous" rupture of a cortical artery. Nineteen similar cases have been reported in the English literature. The source of bleeding was identified as a cortical artery located near the sylvian region in four of our five patients and in most of the reported cases. There are several possible anatomical situations that may predispose a cortical artery to "spontaneous" rupture: (a) spontaneous rupture of a cortical artery at the point of origin of a fragile arterial twig, especially a right-angled branch, a point of potential weakness; (b) rupture of a small artery traversing the subdural space and connecting a cortical artery to the dura mater (a "bridging" artery); (c) adhesions between a cortical artery and arachnoid or dura mater; (d) a knuckle of cortical artery protruding through the arachnoid and adherent to the dura mater. In each situation, the artery is probably torn by a sudden movement of the brain during a vigorous head movement, not severe enough to be considered trauma.

Adult↗
PubMed1983

The metabolism of aldosterone in kidney.

Slices of kidney cortex and medulla from adrenalectomized male rats metabolized aldosterone to at least 4 peaks of polar metabolites as well as reduced metabolites. The majority of the products were ring A-reduced and shown chromatographically to consist of 5 alpha-reduced metabolites; significant quantities of 5 beta-reduced metabolites were also synthesized. Approximately half of the 5 alpha-reduced products cochromatographed with 3 beta,5 alpha-THA and the remainder with 5 alpha-DHA and/or 3 alpha,5 alpha-THA. The anti-mineralocorticoids, spironolactone and progesterone, inhibited renal synthesis of 5 alpha-reduced products of aldosterone by 80%. 5 beta-Reduction was also slightly inhibited. Corticosterone slightly inhibited synthesis of the 5 alpha- and 5 beta-reduced products. Corticosterone and progesterone significantly inhibited the renal synthesis of the polar metabolites of aldosterone, but the inhibition was not significant at this dosage of spironolactone. Interestingly, the nuclei and plasma membranes were shown to be the most active fractions for these aldosterone transformations. Importantly significant quantities of 5 alpha-DHA and/or 3 alpha,5 alpha-THA, which possess 1/10 and 1/30, respectively, of the antinatriuretic activity of aldosterone, were synthesized at these subcellular locations.

Adrenalectomy↗
PubMed1983

Identification of human adenovirus early region 1 products by using antisera against synthetic peptides corresponding to the predicted carboxy termini.

Synthetic peptides were prepared which corresponded to the carboxy termini of the human adenovirus type 5 early region 1B (E1B) 58,000-molecular-weight (58K) protein (Tyr-Ser-Asp-Glu-Asp-Thr-Asp) and of the E1A gene products (Tyr-Gly-Lys-Arg-Pro-Arg-Pro). Antisera raised against these peptides precipitated polypeptides from adenovirus type 5-infected KB cells; serum raised against the 58K carboxy terminus was active against the E1B 58K phosphoprotein, whereas serum raised against the E1A peptide immunoprecipitated four major and at least two minor polypeptides. These latter proteins migrated with apparent molecular weights of 52K, 50K, 48.5K, 45K, 37.5K, and 35K, and all were phosphoproteins. By using tryptic phosphopeptide analysis, the four major species (52K, 50K, 48.5K, and 45K) were found to be related, as would be expected if all were products of the E1A region. The ability of the antipeptide sera to precipitate these viral proteins thus confirmed that the previously proposed sequence of E1 DNA and mRNA and the reading frame of the mRNA are correct. Immunofluorescent-antibody staining with the antipeptide sera indicated that the 58K E1B protein was localized both in the nucleus and in the cytoplasm, especially in the perinuclear region. The E1A-specific serum also stained both discrete patches in the nucleus and diffuse areas of the cytoplasm. These data suggest that both the 58K protein and the E1A proteins may function in or around the nucleus. These highly specific antipeptide sera should allow for a more complete identification and characterization of these important viral proteins.

Adenoviruses, Human↗
PubMed1983

Osteoarthrosis in runners with knee pain.

A clinical and radiological study of the knee joints of twenty middle and long distance runners, complaining of knee pain, was carried out. Osteoarthrosis of varying degree was found in six of the runners. A torn meniscus requiring surgery was found in one athlete, and another had considerable ligamentous laxity - both of these conditions predispose to the development of degenerative changes. Degenerative changes were significantly associated with the presence of genu varum (p less than 0.01) and history of severe injury (p less than 0.05). The number of years spent training was significantly greater in the affected group than in the unaffected group (p less than 0.05).

Adult↗
PubMed1983

Regulation of lymphoblast traffic and localization in mucosal tissues, with emphasis on IgA.

A fundamentally important factor in the expression of immunity at mucosal sites is the migration of primed lymphocytes to, from, and among mucosal tissues. Despite considerable information in recent years on the selective localization of B lymphoblasts, especially those destined to make IgA antibodies in mucosal tissues, the basis for this remains obscure. Several cell-associated factors such as surface characteristics, histo-compatibility type, and organ derivation of the cells play a significant role for T and B lymphoblast localization. Factors that regulate lymphoblast delivery to tissues, such as blood flow, or control emigration from tissues, such as arachidonic acid metabolites, are discussed. Finally, factors such as the presence or absence of high endothelial venules, isotype-specific T helper cells, sex hormones, antigen, macrophages, and iron all may play a significant role in mucosal lymphoblast localization.

Animals↗
PubMed1983

Grain exposure--symptoms and lung function.

Eighty dock workers handling grains and other cargoes were surveyed by respiratory and occupational questionnaires, spirometry, skin tests with common allergens and grain extracts, and serological tests. Sixty-nine of the men reported chest symptoms during exposure to barley dust and 13 men reported evening feverish episodes after handling barley. Symptoms were not related to smoking or atopic status. No gross deficits in lung function were detected. Six men handling barley and four handling non-dusty cargoes had their lung function measured over two working days. Falls in ventilatory capacity occurred in the six workers handling barley but not in the four handling non-dusty cargoes. Six previously unexposed subjects spent 2 h in a barley dust atmosphere of a silo and had lung function measured before and after the exposure. All subjects had falls in ventilatory capacity. In four these lasted 24 h or more and were associated with systemic symptoms. As with cotton dust the agent(s) responsible for symptoms from grain dust exposure remains uncertain. Our findings on the dock workers suggest that specific immunological responses are not involved.

Adult↗