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Biomedical subjects

J Green

Publications and source records attributed to J Green.

At least 541 records · Page 30Linked to original sources
PubMed1986

Steady-state kinetic analysis of soluble methane mono-oxygenase from Methylococcus capsulatus (Bath).

A steady-state kinetic analysis of purified soluble methane mono-oxygenase of Methylococcus capsulatus (Bath) was performed. The enzyme was found to follow a concerted-substitution mechanism. Methane binds to the enzyme followed by NADH, which reacts to yield reduced enzyme and NAD+. The reduced enzyme-methane complex binds O2 to give a second ternary complex, which breaks down to release water and methanol. In this way the enzyme can control the supply of electrons to the active site to coincide with the arrival of methane. Product-inhibition studies (with propylene as substrate) supported the reaction mechanism proposed. Ki values for NAD+ and propylene oxide are reported. The Km for NADH varied from 25 microM to 300 microM, depending on the nature of the hydrocarbon substrate, and thus supports the proposed reaction sequence. With methane as substrate the Km values for methane, NADH and O2 were shown to be 3 microM, 55.8 microM and 16.8 microM respectively. With propylene as substrate the Km values for propylene, NADH and O2 were 0.94 microM, 25.2 microM and 12.7-15.9 microM respectively. Methane mono-oxygenase was shown to be well adapted to the oxidation of methane compared with other straight-chain alkanes.

Alkanes↗
PubMed1986

Preliminary characterisation of torovirus-like particles of humans: comparison with Berne virus of horses and Breda virus of calves.

Pleomorphic virus-like particles have been observed by electron microscopy in the faeces of children and adults with diarrhoea. Some of these particles were approximately 100 nm in diameter and had a "fringe" of closely applied peplomers approximately 10 nm long; they closely resembled Berne virus of horses and Breda virus of calves, the two representatives of a newly proposed family called the Toroviridae. In one sample a toroidal nucleoprotein-like structure was observed within the particles. For two samples a buoyant density of 1.14 g/ml was determined by centrifugation through a sucrose density gradient. One sample possessed a haemagglutinin for rat erythrocytes. The serological relationship between these different viruses was observed by immune electron microscopy, haemagglutination inhibition, and serum neutralisation. The role of these virus-like particles as candidate pathogens of humans is discussed.

Adult↗
PubMed1986

Feeding cycles in smokers, exsmokers and nonsmokers.

Smokers, exsmokers and nonsmokers showed 50 to 150 minute cycles of consummatory behavior (eating and drinking) that appear to reflect a biological rhythm of oral drive. Smokers and exsmokers had significantly shorter cycles, i.e., more frequent consummatory peaks, than nonsmokers. If a greater frequency of consummatory peaks contributes to heightened oral drive in smokers, it may constitute a physiological factor underlying the initiation or maintenance of compulsive smoking and the degree of difficulty in quitting smoking and remaining abstinent.

Activity Cycles↗
PubMed1986

Extreme unilateral hydronephrosis with normal glomerular filtration rate: physiological studies in a case of obstructive uropathy.

A 30-year-old man presented with massive left hydronephrosis caused by congenital stricture of the ureteropelvic junction. Glomerular filtration rate of the post-released kidney (inulin clearance and creatinine clearance) was preserved completely. Simultaneous individual kidney function tests showed the following values expressed as the ratio of post-obstructed to normal kidney: inulin clearance 142 per cent, urine flow rate 475 per cent, sodium clearance 221 per cent and urinary excretion of prostaglandin E2 617 per cent. Urinary osmolality was 257 and 791 mOsm./kg. in the obstructed and normal kidneys, respectively. Administration of indomethacin, a cyclo-oxygenase inhibitor, caused decreased urinary excretion of prostaglandin E2 in both kidneys, with drastic antinatriuresis manifested predominantly in the normal kidney. We conclude that the glomerular filtration rate may be preserved despite huge hydronephrosis, which suggests that the human kidney is salvageable even after a prolonged period of unilateral ureteral obstruction, and the contralateral normal kidney mitigates the volume losses from the obstructed kidney.

Adult↗
PubMed1986

Severity of illness and the teaching hospital.

In the current environment of cost containment pressures on health care providers, teaching hospitals are facing increased financial risks that could jeopardize their special role in the health care delivery system. One of these risks is that the Medicare prospective payment system does not adequately account for severity of illness. Whether teaching hospitals treat a case mix of patients with more severe illness than do nonteaching hospitals was tested in the study reported here using two severity measures, Horn's severity of illness index and Gonnella's "disease staging." Teaching hospitals were found to treat a significantly greater proportion of severely ill patients than community hospitals, especially when measured by the severity of illness index. Differences in case mix of severity of illness among hospitals can have a significant impact on patient care costs, which may not be adequately met by a reimbursement system based on diagnosis related groups. Hospital managers can use severity of illness measures to assess the resource needs of patients and the practice patterns of physicians. If severity of illness measures help describe the special burden of treatment that teaching hospitals bear, they should be used to establish the case for adequate financial support.

Costs and Cost Analysis↗
PubMed1986

Organising a counselling service for problems related to the acquired immune deficiency syndrome (AIDS).

Recent Department of Health and Social Security (DHSS) guidelines on screening procedures for antibody to human T cell lymphotropic virus type III (HTLV-III) have stressed the importance of providing adequate counselling for patients before and after testing. The establishment of a national acquired immune deficiency syndrome (AIDS) counselling training unit has enabled large numbers of National Health Service staff to be trained in this work. Suggestions for the establishment of district counselling facilities are made, based on this training, and some preliminary results showing change from high risk sexual behaviour after counselling are presented.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Comparison of the enzyme immunoassay, immunodiffusion, and complement fixation tests in detecting antibody in human serum to the A antigen of Blastomyces dermatitidis.

Using a new enzyme immunoassay (EIA) and standard immunodiffusion (ID) and complement fixation techniques for antibody to the A antigen of Blastomyces dermatitidis, we tested serum from 27 patients with blastomycosis diagnosed histopathologically or by culture; 20 with diagnoses made during 1981 through 1983 (Group A) and 7 during 1974 through 1976 (Group B). We also studied 30 control subjects with Mycoplasma pneumoniae infection (17 subjects), histoplasmosis (6 subjects), coccidioidomycosis (1 subject) and no known disease (6 subjects). Detectable antibody by all 3 tests was present more often for Group A than for Group B, possibly because of delay in testing. Enzyme immunoassay was the most sensitive test; a 1:8 or greater titer was present in acute-phase serum of all Group A patients tested, and a 1:64 or greater titer was associated with disseminated disease (p = 0.003). A positive ID was also more common in disseminated (88%) than in localized (33%) disease. Enzyme immunoassay titers of 1:16 were present in 4 control subjects, 3 with histoplasmosis. The 100% predictive values of a negative EIA and positive ID suggest that these tests are useful for serologic screening (EIA) and serologic confirmation (ID) of suspected blastomycosis, particularly in disseminated disease. Enzyme immunoassay titers of 1:32 or greater strongly support the diagnosis and titers of 1:16 or less may indicate localized disease or be nonspecific. None of the serologic tests predicted disease progression or reactivation.

Antibodies, Fungal↗
PubMed1986

Comparison of neurothermography and contrast myelography.

Eighty consecutive patients who first had an electronic infrared thermogram (neurothermogram) and a subsequent oil myelogram were studied retrospectively. All patients had cervical and/or lumbosacral radiculopathy for 90 days. Negative neurothermograms were predictive of negative myelograms in 93% of our series. Positive neurothermograms were predictive of positive myelograms in 71% of the patients. The neurothermogram is not a specific test for intraspinal axis lesions as a cause of radiculopathy. Proximal neuropathic lesions of other causes will also produce abnormalities of the sympathetic autonomic (peripheral) nervous system. The major pathophysiologic findings detected by neurothermograms are complimentary to the EMG, NCVS, and late response techniques. Neurothermography was successful in predicting the outcome of myelography in 82% of patients in this study.

Adult↗
PubMed1986

Multiple endocrine neoplasia type I: assessment of laboratory tests to screen for the gene in a large kindred.

We measured multiple components of serum or plasma in 221 members of a kindred with familial multiple endocrine neoplasia type 1 (FMEN1). The kindred showed typical features of FMEN1; the FMEN1 gene could be traced through 7 generations with 74 members identifiable as gene carriers. Between family screening in 1981 and completion of our study in 1985, we identified 16 previously unscreened members as carriers of the FMEN1 gene. The earliest age at diagnosis of FMEN1 was 17. The tests with the greatest yield of abnormal results among carriers of the FMEN1 gene were albumin-adjusted calcium, PTH, gastrin, and (in females) prolactin. The following tests provided little or no use in identifying carriers: prolactin (in males), pancreatic polypeptide, glucagon, glicentin, insulin, growth hormone, motilin, and somatostatin. Primary hyperparathyroidism was the commonest expression of the FMEN1 gene; the gene penetrance for this trait increased from near 0% before age 15 to near 100% after age 40. It appeared prior to development of serious morbidity from hypergastrinemia or hyperprolactinemia. All 42 co-operating members who were alive and expressing the FMEN1 gene in 1984 showed active or treated primary hyperparathyroidism. Primary hypergastrinemia had a prevalence below half of that for primary hyperparathyroidism at all ages and was not diagnosed in the absence of primary hyperparathyroidism. Primary hyperprolactinemia was still less prevalent than primary hypergastrinemia. It was limited almost exclusively to females.

Adolescent↗
PubMed1986

The "jaundiced heart": a possible explanation for postoperative shock in obstructive jaundice.

Patients with obstructive jaundice are susceptible to postoperative shock and kidney failure. The cause of these potentially fatal complications has not been fully clarified. The present study was designed to assess the role of myocardial dysfunction in the hemodynamic disturbance of obstructive jaundice. We studied the effect of isolated cholemia on left ventricular performance in five conscious dogs before and 2 weeks after choledochocaval anastomosis by using measurements of systolic time intervals (STIs) and maximal dp/dt. Mean left ventricular ejection tiem (LVET) decreased after cholemia from 159 +/- 2.8 msec to 139 +/- 2.6 msec (p less than 0.005), while mean preejection period (PEP) and mean PEP/LVET were increased from 41 +/- 8.5 msec to 87 +/- 14 msec (p less than 0.05) and from 0.39 +/- 0.06 to 0.62 +/- 0.1 (p less than 0.01), respectively. During cholemia, STIs were unchanged after intravenous administration of ouabain, whereas in the control period, there was shortening of mean PEP from 71 +/- 8.8 msec to 58 +/- 7.6 msec (p less than 0.05) and of Q-S2 from 257 +/- 12 msec to 235 +/- 14 msec (p less than 0.005) in response to ouabain. Maximal dp/dt decreased after choledochocaval anastomosis from 4543 +/- 593 mm Hg/sec to 3666 +/- 648 mm Hg/sec (p less than 0.025). We conclude that cholemia in the dog is clearly associated with impaired left ventricular performance. The present data also support a previously published in vitro study from our laboratory showing that cholemia blunts the myocardial contractile response to sympathomimetic agents. The cardiodepressor effect of cholemia may explain the increased tendency of patients with obstructive jaundice to postoperative shock and renal failure.

Animals↗
PubMed1986

Retinal angiomatosis: the ocular manifestations of von Hippel-Lindau disease.

The ocular manifestations of a large von Hippel-Lindau pedigree are presented. Of 24 persons with retinal angiomas, 18 are living and are the basis of this report. Nineteen of their 28 affected eyes were asymptomatic with 2 to 4 small tumours per eye. Nine eyes had lost vision secondary to exudative detachment. Seven of these had peripheral disease with rapid recurrences. Two had untreated disc tumours. Tumours less than 1 disc diameter (DD) in size were easily treated with photocoagulation. Multiple treatments of cryotherapy were required for larger tumours. Scleral buckle and early vitrectomy are recommended for vitreous traction. Tumour in a 4-year-old and a de-novo tumour in a 42-year-old lead us to recommend life-time surveillance of patients at risk. Many patients had false negative family histories. A review of the literature leads us to suspect that the majority of retinal angiomas are familial. We emphasize the ophthalmologist's responsibility to investigate such patients.

Adolescent↗