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Biomedical subjects

R J Cook

Publications and source records attributed to R J Cook.

At least 145 records · Page 8Linked to original sources
PubMed1988

Outcome prediction in extradural haematomas.

Extradural haematoma (EDH) is generally a condition of young adult males. It represents only a small percentage of the total number of head injuries admitted to a neurosurgical service, but it must be differentiated from simple concussion, and this means that it is considered in a large number of patients. EDH has the potential for a low mortality rate because of its extraaxial location, but in practice it is approximately 10%. Our results show that about 40% of EDH present with vomiting or nausea and no focal neurological signs. Skull X-ray does not aid in the diagnosis as approximately 35% are reported as being normal. There is a place for conservative treatment of EDH but only if the shift of the midline is minimal (less than 5 mm). A score has been developed to predict accurately a patient's outcome after suffering an EDH. This score includes the Glasgow Coma Scale, pupillary reaction and initial CT scan appearance, and has an accuracy of 88%.

Adolescent↗
PubMed1988

The management of injuries--a review of deaths in hospital.

A prospective review was undertaken of the management of 111 consecutive patients who died in hospital after admission for treatment of injuries. A standard set of data relating to each patient was reviewed by each member of a trauma death audit committee and then by the whole committee. Autopsy reports were available on all patients. Conclusions were drawn concerning defective aspects of patient management and possible avoidance of each death. Injury severity was assessed using the Trauma Score (TS) and Injury Severity Score (ISS). The possibly avoidable death (PAD) rate was 17%. The most common defects in management were related to inadequate fluid resuscitation and delays in definitive management. The greatest contributions to the PAD rate were from inadequate fluid resuscitation, delays and inadequate perception of the severity of injuries or significance of clinical deterioration. Increasing age was related to a higher frequency of PAD. PAD rate in the presence of severe head injury was 8%, but was 63% in the absence of a severe head injury. It is concluded that review of all trauma deaths is an achievable, beneficial and essential part of a hospital-based integrated trauma service. TS and ISS are not sufficiently sensitive to justify their use in selecting deaths for review. Improved blood volume replacement, earlier and more direct management and supervision by senior specialist staff, and elimination of causes of delay in patient management should all decrease the death rate from injuries particularly in patients without severe head injury.

Adolescent↗
PubMed1988

International developments in abortion laws: 1977-88.

During the period between 1977 and the first quarter of 1988, 35 countries liberalized their abortion laws and four countries limited grounds for the procedure. Most legislation has extended abortion eligibility through traditional indications such as danger to maternal health or fetal handicap, but a number of other indications have been created such as adolescence, advanced maternal age, family circumstances, and AIDS or HIV infection. A number of countries have redesigned their abortion laws as part of a comprehensive package to facilitate access to and delivery of contraception, voluntary sterilization, and abortion services. Abortion litigation has increased and stimulated the liberalization of abortion provisions and the support of women's autonomous choice within the law. In Canada, the entire criminal prohibition of abortion was held unconstitutional for violating women's integrity and security. In contrast, Latin American and other constitutional developments may limit legal abortion to instances of danger to women's lives.

Abortion, Induced↗
PubMed1988

Cervical cord extradural haematoma with familial cutaneous haemangiomas.

This case report confirms the link between familial cutaneous haemangiomas and haemangiomas of the spinal extradural space. Haemorrhage from a cervical extradural haemangioma may cause a haematoma resulting in an anterior cord syndrome. Recovery is possible with early diagnosis and surgical decompression at the involved level. If the diagnosis is not made the patient may die from this extradural cervical compression. Diagnosis involves myelography with spinal angiography to confirm the site and extent of both haemangioma and extradural haematoma.

Adolescent↗
PubMed1987

A 16 year old boy with poor vision and nasal obstruction.

A 16 year old boy presented with visual deterioration and nasal obstruction. Investigations revealed a destructive pituitary tumour with extension into his skull base and nasopharynx. This unusual prolactin-secreting adenoma was treated by both surgery and bromocriptine.

Adenoma↗
PubMed1987

Spousal veto over family planning services.

In many countries a spouse, usually the husband, can veto a partner's use of family planning services. Where spousal veto acts as a barrier to family planning services it represents a serious threat to the lives and health of women and children. Removal of spousal authorization requirements has been shown to increase the use of family planning services. The Family Guidance Association of Ethiopia, for example, removed their requirement in 1982 and clinic utilization increased by 26 per cent within a few months. Courts of several countries have held that spousal veto practices violate principles of personal privacy and autonomy and the right to health care. The effect of such judgements has been to reinforce rights to sexual nondiscrimination found, for example, in national constitutions and the Convention on the Elimination of All Forms of Discrimination against Women. This article discusses the nature and application of spousal veto practices, explains how such requirements can violate certain human rights, and explores possible remedies to this problem, including ministerial, legislative, and judicial initiatives.

Family Planning Services↗
PubMed1986

Characterization of an antibiotic produced by a strain of Pseudomonas fluorescens inhibitory to Gaeumannomyces graminis var. tritici and Pythium spp.

The production, isolation, and characterization of an antibiotic substance from cultures of Pseudomonas fluorescens 2-79 (NRRL B-15132) is described. P. fluorescens 2-79 originally was isolated from the roots of wheat and is suppressive to the wheat root disease take-all caused by Gaeumannomyces graminis var. tritici. The antibiotic was isolated from potato glucose broth cultures of strain 2-79 by solvent extraction. It was purified by silica gel column chromatography and was a greenish yellow, needle-shaped crystal with a melting point of 242 degrees C (decomposition). It was soluble in methylene chloride, chloroform, acetone, 2 N sodium hydroxide, and 2 N hydrochloric acid and was insoluble in water, methanol, ethyl acetate, tetrahydrofuran, diethyl ether, carbon tetrachloride, hexane, and petroleum ether. On the basis of UV, infrared, 1H-nuclear magnetic resonance, 13C-nuclear magnetic resonance, mass spectral analysis, and elemental analysis, the structure of the antibiotic is proposed to be a dimer of phenazine carboxylic acid. Lithium aluminum hydride reduction of the antibiotic yielded hydroxymethyl phenazine as a major product which retained most of the biological characteristics of the parent molecule. There were no toxic symptoms when mice received this antibiotic by oral doses up to 464 mg/kg. The antibiotic showed excellent activity against several species of fungi, including the wheat pathogens Gaeumannomyces graminis var. tritici, Rhizoctonia solani, and Pythium aristosporum; and it may have a role in suppression of take-all in vivo by strain 2-79.

Aluminum↗
PubMed1985

The amino acid sequences of the flavin-peptides of dimethylglycine dehydrogenase and sarcosine dehydrogenase from rat liver mitochondria.

The flavoenzymes dimethylglycine dehydrogenase (EC 1.5.99.2) and sarcosine dehydrogenase (EC 1.5.99.1) contain covalently bound FAD linked via the 8 alpha-position of the isoalloxazine ring to the imidazole N(3) of a histidine residue (Cook, R. J., Misono, K. S., and Wagner, C. (1984) J. Biol. Chem. 259, 12475-12480). The flavin-peptides from tryptic digests of these two enzymes have been isolated and sequenced. Automated sequence analysis showed that the flavin-peptide from dimethylglycine dehydrogenase contained 25 amino acid residues in the following sequence: Ser-Glu-Leu-Thr-Ala-Gly-Ser- Thr-Trp-His(flavin)-Ala-Ala-Gly-Leu-Thr-Thr-Tyr-Phe-His-Pro-Gly-Ile-A sn-Leu-Lys. The sequence determined for the flavin-peptide from sarcosine dehydrogenase contained 14 amino acid residues Leu-Thr-Ser-Gly-Thr-Thr-Trp-His(flavin)-Thr-Ala-Gly-Leu-Gly-Arg.

Amino Acid Sequence↗
PubMed1985

Inhibition of glycine N-methyltransferase activity by folate derivatives: implications for regulation of methyl group metabolism.

Glycine N-methyltransferase, an enzyme that uses S-adenosylmethionine to methylate glycine with the production of sarcosine, was recently shown to be identical with a major folate binding protein of rat liver (Cook, R.J. and Wagner, C. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 3631-3634). We now present evidence that 5-methyltetrahydropteroylpentaglutamate (5-CH3-H4PteGlu5) is bound with high specificity, and is a powerful inhibitor of the enzyme. It is proposed that this information may be used to modify the "methyl trap" hypothesis which describes how the availability of one-carbon units is regulated by folate, vitamin B12 and methionine.

Animals↗
PubMed1985

Legal abortion: limits and contributions to human life.

The traditional approach to abortion has been to regard it as disposing of human life, even when it is justifiable to induce abortion in accordance with legal and ethical principles. Contraception as distinct from abortion has never been so treated even though, in some respects, the biological processes involved in contraception and abortion raise similar issues. This is particularly so when contraception is by an intrauterine device or a postcoital technique which can prevent implantation rather than fertilization. Modern evidence shows that abortion is not only a loss of human life, but--paradoxically--is also a biological condition of human life. An unavoidably high rate of spontaneous loss of embryos has been shown to arise in the course of natural reproduction, due either to failure of implantation or to loss, such as the 'vanishing twin' of children born in single births. More common than the vanishing twin is spontaneous loss after implantation. Planned embryonic loss in artificial reproduction duplicates rather than defies nature. Further, sociological perceptions indicate that the availability of reliable prenatal diagnosis, especially of genetic conditions, and of induced abortion to terminate dysgenic life, may free couples to conceive and bear healthy children they would otherwise not have conceived. Moreover, prenatal diagnosis, for example by amniocentesis, may increasingly permit maternal or fetal treatment and so encourage the continuation of a pregnancy which might otherwise have been terminated.

Abortion, Illegal↗
PubMed1985

Enzymatic properties of dimethylglycine dehydrogenase and sarcosine dehydrogenase from rat liver.

Dimethylglycine dehydrogenase (EC 1.5.99.2) and sarcosine dehydrogenase (EC 1.5.99.1) are flavoproteins which catalyze the oxidative demethylation of dimethylglycine to sarcosine and sarcosine to glycine, respectively. During these reactions tightly bound tetrahydropteroylpentaglutamate (H4PteGlu5) is converted to 5,10-methylene tetrahydropteroylpentaglutamate (5,10-CH2-H4PteGlu5), although in the absence of H4PteGlu5, formaldehyde is produced. Single turnover studies using substrate levels of the enzyme (2.3 microM) showed pseudo-first-order kinetics, with apparent first-order rate constants of 0.084 and 0.14 s-1 at 23 and 48.3 microM dimethylglycine, respectively, for dimethylglycine dehydrogenase and 0.065 s-1 at 47.3 microM sarcosine for sarcosine dehydrogenase. The rates were identical in the absence or presence of bound tetrahydropteroylglutamate (H4PteGlu). Titration of the enzymes with substrate under anaerobic conditions did not disclose the presence of an intermediate semiquinone. The effect of dimethylglycine concentration upon the rate of the dimethylglycine dehydrogenase reaction under aerobic conditions showed nonsaturable kinetics suggesting a second low-affinity site for the substrate which increases the enzymatic rate. The Km for the high-affinity active site was 0.05 mM while direct binding for the low-affinity site could not be measured. Sarcosine and dimethylthetin are poor substrates for dimethylglycine dehydrogenase and methoxyacetic acid is a competitive inhibitor at low substrate concentrations. At high dimethylglycine concentrations, increasing the concentration of methoxyacetic acid produces an initial activation and then inhibition of dimethylglycine dehydrogenase activity. When these compounds were added in varying concentrations to the enzyme in the presence of dimethylglycine, their effects upon the rate of the reaction were consistent with the presence of a second low-affinity binding site on the enzyme which enhances the reaction rate. When sarcosine is used as the substrate for sarcosine dehydrogenase the kinetics are Michaelis-Menten with a Km of 0.5 mM for sarcosine. Also, methoxyacetic acid is a competitive inhibitor of sarcosine dehydrogenase with a Ki of 0.26 mM. In the absence of folate, substrate and product determinations indicated that 1 mol of formaldehyde and of sarcosine or glycine were produced for each mole of dimethylglycine or sarcosine consumed with the concomitant reduction of 1 mol of bound FAD.

Anaerobiosis↗