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Biomedical subjects

M E Scott

Publications and source records attributed to M E Scott.

At least 91 records · Page 5Linked to original sources
PubMed1981

2,3-Dehydro-4-epi-N-acetylneuraminic acid; a neuraminidase inhibitor.

Treatment of N-acetylneuraminic acid methyl ester with sulfuric acid and acetic anhydride at 50 degrees followed by deacetylation gave 2,3-dehydro-2-deoxy-N-acetylneuraminic acid methyl ester and methyl 5-acetamido-2,6-anhydro-2,3,5-trideoxy-D-glycero-D-talo-non-2-enonate (2,3-dehydro-4-epi-NeuAc methyl ester) in equal yields (approximately 40% each). The structure of the latter was ascertained primarily from analysis of its mass spectrum and 1H- and 13C-nuclear magnetic resonance spectra. The relative proportions of these two glycals in the foregoing reaction was dependent on temperature, as at 0 degrees, the yield of 2,3-dehydro-4-epi-NeuAc was markedly diminished. A minor by-product of this acetylation reaction was 2-methyl-(methyl 7,8,9-tri-O-acetyl-2,6-anhydro-2,3,5-trideoxy-D-glycero-D-talo-non-2-enonate)-[ 4,5-d]-2-oxazoline. Based upon this finding and additional interconversion experiments, a mechanism involving the intermediacy of the latter oxazoline to account for the epimerization is proposed. These glycals and their methyl esters are competitive inhibitors of Arthrobacter sialophilus, neuraminidase, suggesting that the 4-hydroxyl group must be equatorially oriented for maximal enzyme inhibition.

Arthrobacter↗
PubMed1981

Lithium therapy for cocaine-induced psychosis: a clinical perspective.

The incidence of cocaine-induced psychosis has increased with the rise in popularity of cocaine as the recreational drug of choice. Neuroleptic agents have been used to control the hallucinations, paranoia, and hyperactivity of the acute psychotic episodes. Lithium has been suggested as an alternative therapeutic agent for cocaine abusers. This study reports the results of successful lithium therapy for three cases of cocaine-induced psychosis. Future directions for clinical use and research are recommended.

Adult↗
PubMed1980

Prevalence and intensity of Typhlocoelum cucumerinum (Digenea) in wild anatids of Quebec, Canada.

The upper respiratory tracts of 534 wild anatids representing 20 species, shot during the 1976, 1977 and 1978 hunting seasons, were examined for Typhlocoelum cucumerinum (Rudolphi, 1809). Typhlocoelum cucumerinum cymbium (Diesing, 1850) were recovered from Anas platyrhynchos, Anas rubripes, Anas acuta, Anas discors and Anas crecca. The maximum prevalence (16.7%) and intensity of infection (1.6) occurred in mallards (A. platyrhynchos). Aythya valisineria and Aythya marila harboured Typhlocoelum cucumerinum cucumerinum (Rudolphi, 1809). The maximum prevalence (14.3%) and intensity of infection (8.0) occurred in canvasbacks (A. valisineria). Of the 13 other species of ducks examined, none were infected with T. cucumerinum.

Animals↗
PubMed1980

Comparison of propranolol and inderal L.A. in patients with angina.

TWELVE patients with moderately severe angina pectoris completed a double blind cross-over comparison of conventional propranolol (40 mg q.i.d.) and Inderal L.A. (160 mg once daily) with regard to therapeutic effectiveness, blood levels, compliance and patient acceptability.Exercise tolerance was assessed using standardised treadmill testing at 1, 2, 4, 8, 12 and 24 hours after the morning dose. The double placebo technique was used.Patient compliance was excellent for both regimes and no serious side effects were reported. No significant differences in exercise tolerance or blood levels were observed between the two treatments at any time.

Aged↗
PubMed1980

The battered spouse syndrome.

This paper deals with spouse abuse problems. Male abuse of the female is preponderant statistically, but female abuse of the male also occurs, with unknown frequency. Four case histories and a brief resume of treatment approach are presented. The goal of treatment should be to correct the skew of the marriage, no matter which sex is being abused.

Child Abuse↗
PubMed1979

The nature of the slow metal ion-dependent conformational transition in bovine prothrombin.

Kinetic parameters characterizing the slow structural isomerization observed via metal ion-dependent intrinsic fluorescence quenching of bovine prothrombin Fragment 1 have been determined. From forward and reverse rate constants, an equilibrium constant of approx. 0.25 is calculated. This result is consistent with the hypothesis that there exists, in the absence of metal ions, an equilibrium between two forms of bovine Fragment 1, one of which can interact rapidly with Ca2+ and subsequently with phospholipid. The other form of Fragment 1 cannot interact with Ca2+ in a manner that yields a phospholipid-binding form of the protein. Interconversion of these two forms of Fragment 1 occurs and may involve the isomerization of a proline residue.

Animals↗
PubMed1979

Physical studies on isolated human prothrombin fragment-2. Comparisons with human prothrombin fragment-1.

Variation of pH strongly affects the fluorescence intensity of human prothrombin fragment-1 in a manner suggesting contributions from a number of protropic equilibria including groups with apparent pKa values near 3.0. These results suggest a structural role for pK1a of gamma-carboxyglutamic acid noieties. Added calcium ions (9 mM calcium chloride) quench the fluorescence titration curve uniformly above pH 4. Below pH 4, however, the titration curve in the presence of calcium ions suggests that calcium-ion-dependent processes leading to fluorescence quenching are pH-dependent. Upon back titration of human fragment-1, from pH 9, hysteresis is observed. Human prothrombin fragment-2 fluorescence titration curves are relatively broad at low pH suggesting the titration of normal carboxyl groups. The titration curves of fragment-2 are not affected by the presence of calcium ions, and hysteresis occurs upon back titration from low pH values. Circular dichroism (CD) Cotton effects appear at 232 nm and 280 nm and a trough appears at 203 nm in the CD spectrum of human prothrombin fragment-2. The Cotton effects in the region from 230 nm to 300 nm are sensitive to pH, ellipticity values at 232 nm increasing from approximately 300 at pH 2.5 to 1300 (degree-cm/decimole) at neutral pH and finally become negative at high pH values. In contrast to fragment-1, at neutral pH the fragment-2 Cotton effect at 232 nm is insensitive to the presence of 8 mM calcium chloride.

Calcium↗
PubMed1979

The effects of calcium ions and pH on bovine prothrombin fragment 1. Intrinsic fluroescence studies.

The effects of pH and Ca2+ on the intrinsic fluorescence of bovine prothrombin fragment 1 were investigated to deduce the nature of protein functional groups involved in Ca2+ binding to fragment 1. From pH values of 9 to 3, increasing the H3O+ concentration results in quenching of the fluorescence of fragment 1. Reversible pH-titration curves are obtained which appear to consist of two regions. From pH 4 to pH6.5 a broad titration curve is obtained, whereas from pH6.5 to 9 a more pronounced titration behaviour is evidenced by a group or groups on fragment 1 with an apparent pKa of approx. 7.5. In contrast, the apparent association constant for Ca2+ and fragment 1 shows a sharp pH-dependence in the region between pH7 and 8 with tighter Ca2+ binding at higher pH values. A PKa of approx. 7.5 can be estimated for the group or groups on fragment 1 linked to the tight binding of Ca2+. Both H3O+ and Ca2+ result in blue-shifts in the wave-lengths of fragment-1 emission. These results are interpreted in terms of H+ - and Ca2+ - induced changes in the conformation of fragment 1 as a result of surface-charge neutralization.

Animals↗
PubMed1979

Connective tissue activation. XIV. Composition and actions of a human platelet autacoid mediator.

Connective tissue activating peptide-III (CTAP-III) isolated from human platelets is a potent mitogen for human connective tissue cells in culture in addition to stimulating glycosaminoglycan synthesis, glucose consumption, and lactate formation. The amino acid composition of apparently homogeneous CTAP-III was determined, confirming the presence of two disulfide links and providing a calculated molecular weight of 11,633 daltons. Comparison of the mitogenic activity of serum and plasma-serum suggests that CTAP-III is a major mitogenic component of human serum. Seventeen strains of human connective tissue cells (synovial, cartilage, dermal and thyroid) incorporated [3H]-thymidine at up to 30 times control at levels under the influence of microgram quantities of CTAP-III and caused detectable increases in thymidine incorporation at levels as low as 10-29 ng/ml. Prostaglandin E1 (0.01 microgram/ml) and dibutyryl cyclic AMP (25 microgram/ml) potentiated the glycosaminoglycan stimulating effect of CTAP-III, but not its mitogenic effect. Cycloheximide and actinomycin D blocked the biologic actions of CTAP-III. Cortisol and penicillamine had little effect on the mitogenic activity of CTAP-III, whereas antirheumatic agents such as acetylsalicylic acid and phenylbutazone opposed the mitogenic activity when added to cultures at clinically relevant concentrations. A weak antiheparin factor secreted by platelets, low affinity platelet factor 4 (LA-PF4), was shown to be similar to CTAP-III in biologic actions, electrophoretic mobility, amino acid composition, and antigenic determinants.

Amino Acids↗
PubMed1979

Pericardial effusion complicating psittacosis infection.

A 13-year-old schoolboy developed a moderately large pericardial effusion during the course of infection with psittacosis. The value of echocardiography in differentiating between pericardial effusion and myocarditis is shown.

Adolescent↗
PubMed1977

Connective tissue activation. XI. Stimulation of glycosaminoglycan and DNA formation by a platelet factor.

This report describes a small basic protein found in human platelets which stimulates hyaluronic acid formation, glucose uptake, and lactate formation in several types of human connective tissue cells. In addition, it stimulates in incorporation of [3H] methyl thymidine into DNA in human synovial cell cultures. This platelet factor (connective tissue activating peptide-II, CTAP-III) clearly differs form CTAP-I, found in human lymphocytes, and may play a role as a mediator of the inflammatory process.

Blood Platelets↗
PubMed1977

Spinal osteoporosis in the aged.

Spinal osteoporosis is a common condition in the elderly. Its aetiology is unknown although endocrine and metabolic factors appear to be involved. The diagnosis is relatively straight-forward but treatment is unsatisfactory. In this article the author discusses the disease as a whole and presents his views on the management of the condition.

Aged↗