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Biomedical subjects

M Cooper

Publications and source records attributed to M Cooper.

At least 253 records · Page 14Linked to original sources
PubMed1987

Effect of osmolarity of artificial tear drops on relief of dry eye symptoms: BJ6 and beyond.

Patients with clinically well defined keratoconjunctivitis sicca (KCS) participated in two trials of hypo-osmolar tear substitutes. The trials were double masked, single crossover studies with computer generated random order allocation and were conducted by postal questionnaire. In the first trial a hypo-osmolar formulation using polyvinylpyrrolidone and hydroxyethyl cellulose was compared with the patients' usual treatment (BJ6 or hypromellose) and found to be inferior, especially in respect of blurring and stickiness caused by higher viscosity. In the second trial hypo-osmolar preparations of BJ6 and hypromellose were compared with their iso-osmolar equivalents and found not to be significantly different in their effects. Hypo-osmolarity alone does not seem to guarantee relief of symptoms in KCS. Other factors including viscosity and colloid osmotic pressure may be more significant.

Cellulose↗
PubMed1987

Exercise-induced changes in urinary water and mineral output during the menstrual cycle.

This study monitors changes in urinary excretion of water and minerals before and after exercise in pre-menopausal women and in those using oral contraception. Resting urine flow rate was lower and sodium output significantly higher (p less than 0.02) during the normal post-menstrual phase than during other phases of the cycle. These changes were unrelated to glomerular filtration rate and might impede maximal performance. After exercise an oliguria and hyponatriuresis were most pronounced during the menstrual phase. In addition the resting urinary output of calcium and magnesium were unrelated to normal oestrogenic and progestegenic cyclic surges. Amongst oral contraceptive users, resting excretion of water, minerals and creatinine were all significantly lower than general menstrual cycle values (p less than 0.01) and further reductions in salts and water output occurred with exercise. Basal calcium and magnesium excretion rates were significantly lower than general menstrual cycle values (p less than 0.05). Renal conservation of water and salts for 'pill' takers may affect renal homeostasis. The consequences of mineral retention are unknown.

Adult↗
PubMed1987

Fructose-1-phosphate and fructose-1,6-bisphosphate aldolases in the small intestinal mucosa.

Reference values are presented for the activity of fructose-1-phosphate aldolase (F1PA) and fructose-1,6-bisphosphate aldolase (FBPA) in the small intestinal mucosa of 32 nonaffected children, 8 nonaffected adults and 2 children with hereditary fructose intolerance (HFI). The 96% confidence limits for F1PA in children are 1.55 to 43.0 u/g protein, completely distinct from the results of the two affected children (1.3 and less than 0.1 u/g protein). With fructose-1,6-bisphosphate as subtrate, the 96% confidence limits are 10 to 324 u/g protein and the values for the two affected children, 23.7 and 9.3 u/g. Among the nonaffected children two mucosal biopsies with F1PA activities less than 1.55 u/g were found. In one mucosal biopsy among the nonaffected children an FBPA activity less than 10 u/g was recorded. The data are interpreted as indicating that the determination of F1PA activity in intestinal mucosa is a highly sensitive test in detecting individuals with HFI. However, the specifity of the test is not absolute. Diagnosis should be based on both clinical and laboratory considerations. The determination of FBPA activity in the same biopsy specimen does not contribute substantially to the differential diagnosis.

Adult↗
PubMed1986

EBV-negative and -positive Burkitt cell lines variably express receptors for B-cell activation and differentiation.

The expression of receptors for proliferation and differentiation factors was analyzed by indirect immunofluorescence on 29 Burkitt lymphoma (BL) cell lines previously classified into 3 groups on the basis of their reactivity with 8 monoclonal antibodies (MAbs), including anti-CALLA, BL13 and TU1. BL13 and HB5 antibodies recognize different epitopes of the EBV/CR2 receptors. The determinant recognized by BL13 has been previously shown to be expressed only on cell lines of the first two groups, supposed to derive from the germinal center and to be negative on a third group of lines of putative BM origin and established from sporadic cases of BL. In contrast, and as expected from its reactivity on normal B cells in the BM or in the lymph nodes, HB5 antibody reacts with all BL lines except one. The receptor for transferrin is expressed on the 29 lines. Two new MAbs, Bac-1 and B1H5, could recognize respectively receptors for BCGF1 and BCGF2. Bac-1 reacts with 15 of 17 BL lines belonging to the first two groups and 7 of 12 BL lines of the third group; 14 of 15 EBV + lines express Bac-1. No BL line expresses B1H5. The IL2 receptor is weakly expressed on 5 EBV + cell lines and one EBV (-) line. All delta are BCGF1-positive. The almost constant expression of BCGF1 receptor on EBV + cell lines is the only strict relation between the expression of receptors for growth factors and their characteristics (i.e. EBV association, translocation, ethnic origin and clinical presentation). The maturation stage or the origin of BL cell lines in relation to the expression of growth factor receptors and the functional significance of these receptors will be discussed.

Antigens, Neoplasm↗
PubMed1986

Autonomous activation of B and T cells in antigen-free mice.

The spleen of adult antigen-free mice contains a sizable proportion (5-15%) of activated cells in all lymphocyte sets, as marked by the membrane expression of immunoglobulins, L3T4 and Lyt-2 antigens. The frequency of activated cells is very high in early post-natal life, and reaches adult levels by 6 weeks of age when it is comparable to that observed in healthy unmanipulated mice raised in conventional conditions. The effector B cell compartment is quantitatively similar in antigen-free mice and specific pathogen-free mice, but the former is deficient in isotype diversification, since IgG- and IgA-secreting cells are drastically reduced. The effector T cell compartment is slightly reduced in number, but is equally competent in providing help or suppression of syngeneic B cells. The results indicate the existence of a compartment of the immune system displaying autonomous self-determined activity which is predominant early in life. This compartment, physically localized to the spleen, appears to be distinct from an antigen-dependent compartment which is essential for the development of peripheral lymphoid organs draining sites of "natural" environmental immunization.

Animals↗
PubMed1986

On the nature of the receptor mediating the action of 5-hydroxytryptamine in potentiating responses of the mouse urinary bladder strip to electrical stimulation.

Superfused mouse bladder strip responded to electrical stimulation (ES) by twitch contractions. These contractions were potentiated by 5-hydroxytryptamine (5-HT; 0.03-3.0 microM). Three tryptamine analogues were tested for their ability to potentiate the responses to ES and their relative activities were compared with values in the literature. 5-Carboxamidotryptamine was more potent than 5-HT, N-omega-methyl 5-HT was about equipotent, and alpha-methyl 5-HT was much less potent. Exogenous noradrenaline did not reduce the effect of 5-HT, although it reduced the response of the tissue to ES. The maximum increase in tissue tension evoked by 5-HT was unaltered by phentolamine (1 microM) or bretylium (25 microM). These results show that 5-HT did not act on the bladder by inhibiting the release of catecholamines from intrinsic nerves. The effect of 5-HT proved very resistant to attempts to block it with conventional 5-HT antagonists. Several antagonists were studied including ketanserin, methysergide, methiothepin, and MDL 72222 but even at concentrations as high as 1 microM none of them exhibited any marked inhibitory effect against the action of 5-HT. At 10 microM some compounds showed activity, but none abolished the effect except methiothepin - and its action was not surmountable by increasing the concentration of 5-HT. Thus the effect of 5-HT on the bladder was not mediated by 5-HT receptors of types 'M', 'D' or 5-HT2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Haemagglutination patterns of Aeromonas spp. related to species and source of strains.

The study included 138 A. sobria and 182 A. hydrophila isolated in Perth from samples of diarrhoeal or non-diarrhoeal faeces or from domestic water. Strains were grouped in relation to agglutination of human, horse, rat and guinea pig erythrocytes and the effect of sugars on haemagglutination. Agglutination of red cells of all four species (primary group 1) was most commonly associated with A. sobria, particularly those strains isolated from faeces of patients with diarrhoea. Most A. hydrophila associated with diarrhoea also belonged to group 1 but A. hydrophila from non-diarrhoeal stools or from water most commonly agglutinated human and guinea pig cells but not horse erythrocytes (primary groups 2 and 3). Fucose-resistant haemagglutination (FRHA) of strains in primary group 1 occurred with about 68% of the strains of A. sobria associated with diarrhoea. Mannose-resistant haemagglutination (MRHA) was limited to 29% of strains of A. sobria associated with diarrhoea. The predominance of primary group 1 among strains of Aeromonas spp. associated with diarrhoea and the proportion of these strains showing FRHA suggest that haemagglutination of cells from human, horse, rat and guinea pig, particularly if fucose-resistant, should be considered in a search for characteristics, which possibly contribute to virulence of Aeromonas spp.

Aeromonas↗
PubMed1986

Safety and efficacy of pacing for ventricular tachycardia.

This study was undertaken to determine the safety and efficacy of three different pacing modalities on the termination of ventricular tachyarrhythmias. Thirty-two patients were studied in the electrophysiology laboratory. Three randomized pacing modalities were selected for attempted conversion: auto increment, auto burst, and random burst. In all three groups, arrhythmias with cycle lengths shorter than 230 ms required DC shock, with one exception. Those longer than 230 ms were terminated by pacing in 85% of cases. There was a 15% rate of acceleration. Thus, antitachycardia pacing for ventricular tachyarrhythmias should be considered only with defibrillating back-up.

Aged↗
PubMed1986

Development of an immunofluorescence test for the serodiagnosis of herpes zoster ophthalmicus.

An indirect immunofluorescence test has been developed and evaluated for the serodiagnosis of herpes zoster ophthalmicus (HZO) by the detection of antivaricella zoster virus (VZV) antibody. The results show that, in patients with HZO, anti-VZV IgG antibody titre usually rises rapidly after onset. One hundred and seven of the 134 sera (80%) from patients with a clinical diagnosis of HZO had an anti-VZV IgG titre of greater than or equal to 256, and IgM antibody at a level of 1 in 8 was present in six of them. In comparison only two of the 216 sera (1%) from patients with a clinical diagnosis of ocular infections other than those caused by VZV had such IgG titres. It was concluded that, on the basis of results of a single sample of serum, it is possible to make a provisional diagnosis of HZO with a high degree of confidence.

Antibodies, Viral↗
PubMed1985

Evidence for purinergic transmission in mouse bladder and for modulation of responses to electrical stimulation by 5-hydroxytryptamine.

Electrical stimulation (ES) contracted superfused mouse bladder, and 10(-7) M tetrodotoxin (TTX) abolished the twitches without impairing responses to acetylcholine (ACh) or beta,gamma-methylene ATP. ES acted largely through nerves which were not cholinergic, adrenergic or histaminergic. They may be purinergic because the bladder was contracted by stable analogues of ATP, and after desensitisation by a high concentration of alpha,beta-methylene ATP the response to ES was selectively reduced. 5-Hydroxytryptamine (5-HT) at 0.03-3 X 10(-6) M and tetraethylammonium (TEA) at 0.1-10 X 10(-3) M potentiated responses to ES, on average by 64% and 182%. Pempidine had no effect on responses to ES. The action of TEA was different from that of 5-HT; potentiation of responses was greater than could be produced by 5-HT, and whereas 5-HT did not increase responses to ACh, TEA markedly increased twitch tensions. The mode of action of 5-HT is not clear.

Adenosine Triphosphate↗
PubMed1985

Computed tomography and the prediction of pancreatic abscess in acute pancreatitis.

Pancreatic abscess has become the most common cause of death from acute pancreatitis. Since computed tomography (CT) permits noninvasive imaging of the peripancreatic anatomy, the relationship of early CT findings to late pancreatic sepsis has been evaluated in 83 patients with acute pancreatitis. Pancreatic abscesses developed in 18 patients and were responsible for five of the six deaths in this study. Initial CT findings were graded: A = normal, in 12 patients; B = pancreatic enlargement alone, in 19; C = inflammation confined to pancreas and peripancreatic fat, in 17; D = one peripancreatic fluid collection, in 12; and E = two or more fluid collections, in 23. The incidence of pancreatic abscess in grades A and B was 0%; in grade C, 11.8%; in grade D, 16.7; and in grade E, 60.9%. The severity of pancreatitis was also graded by previously reported prognostic signs as "mild" (0-2 signs) in 56 patients, "moderate" (3-5 signs) in 22, and "severe" (greater than or equal to 6 signs) in five patients. The incidence of abscesses in mild disease was 12.5%; in moderate, 31.8%; and in severe, 80%. Fluid collections on CT resolved spontaneously in 19 of 35 (54.3%) patients. Abscess developed in two patients with no fluid collections on initial CT study. No abscess occurred in 31 patients with CT grades A or B, and in one of 22 patients (4.5%) with CT grade C or D and less than three positive prognostic signs. Among 30 patients with CT grade E or CT grade C or D and three or more positive prognostic signs, 17 (56.7%) developed abscesses. All deaths were in patients with five or more positive prognostic signs. Early imaging of the pancreas by CT identifies a group of patients with increased risk of pancreatic abscess. Identification of this group is improved further by use of early objective prognostic signs.

Abscess↗