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Biomedical subjects

M Young

Publications and source records attributed to M Young.

At least 271 records · Page 15Linked to original sources
PubMed1989

Stability of reiterated sequences in the Bacillus subtilis chromosome.

The instability of reiterated sequences in the Bacillus subtilis chromosome that was previously reported (M. Young, J. Gen. Microbiol. 130:1613-1621, 1984) results from the presence of a truncated pC194 replication origin together with an intact replication protein A gene in the amplified DNA. Removal of the truncated pC194 replication origin or inactivation of replication protein A stabilizes reiterated sequences, whereas provision of replication protein A in trans destabilizes them. We suggest that residual activity of protein A at the truncated replication origin generates single-stranded DNA, which stimulates recombination between repeated sequences and thus destabilizes amplified structures.

Bacillus subtilis↗
PubMed1989

Differences in mortality and cardiovascular morbidity during a 3-year follow-up of transient ischemic attacks and minor strokes.

We prospectively followed 78 patients with transient ischemic attacks (TIAs) from the carotid artery territory and 45 patients with minor ischemic strokes for 3 years. The mean +/- SD age of the patients in the TIA group was 66.9 +/- 7.9 years compared with 68.8 +/- 6.7 in the minor stroke group. Mortality among the TIA patients was significantly higher than that among minor stroke patients (18 of 78 compared with two of 45, p less than 0.01); mortality in the minor stroke group was not higher than that in the background population, whereas mortality in the TIA group was almost twice as high. The most common cause of death in the TIA group was myocardial infarction, and morbidity due to myocardial infarction and new TIA was higher in the TIA group than in the minor stroke group (35 events compared with seven), whereas no difference was found regarding stroke (five strokes compared with eight). Preexisting vascular disease implied an increased risk of mortality and morbidity in the TIA group. We conclude that carotid-territory TIA indicates a worse prognosis than minor stroke as mortality is higher in TIA patients at the same preexisting vascular disease prevalence and stroke frequency.

Aged↗
PubMed1989

Malignant melanoma lately diagnosed.

To assess the clinical impression that patients in Dublin were presenting with late, deep, poor prognosis lesions, a 10 year retrospective review of patients with malignant melanoma was performed. The pathological data on 186 patients was examined and clinical follow-up obtained on 151 of these (80%). The mean period of follow-up was 35 months. Females predominated in a ratio of 3:1. Incidence figures for the two five year periods (1976-80) and (1981-85) indicated a rise in the latter period of over 100%. There was a marked delay in presentation after the onset of symptoms i.e. new pigmented lesions or changes in pre-existing lesions (mean = 21 months). Only 45% of lesions were less than 1.5mm in depth. Females presented with a higher percentage of good prognosis lesions reflected in a superior five year survival figure of 70% compared with 43% for males. The results of this study suggest an increase in incidence and mortality from malignant melanoma in this country. Patients appear to be unaware of the significance of pigmented lesions, presenting late with deep poor prognosis tumours.

Adolescent↗
PubMed1989

Acute diseases of the pancreas and biliary tract. Management in the emergency department.

Pancreatitis, commonly encountered in the Emergency Department, possesses a very broad clinical spectrum and may be associated with shock and multiple organ failure. Its diagnosis is based on clinical, laboratory, and radiographic data, but there is no gold standard. Biliary tract disease ranges in severity from cholelithiasis with colic to acute suppurative cholangitis, which may lead to shock. Clinical examination and imaging studies are most useful in these disorders, and definitive treatment is primarily surgical.

Acute Disease↗
PubMed1989

Direct immunofluorescence testing of skin biopsies--an under-utilised diagnostic aid.

Direct immunofluorescence testing of skin biopsies is a simple inexpensive and relatively non-invasive diagnostic procedure currently widely used in dermatological practice for the investigation and diagnosis of dermatological and immunological disorders. This paper reviews the value and applicability of the procedure in a variety of disease states. The sensitivity and specificity of the test to a spectrum of clinical conditions should encourage its more widespread use in general medical and rheumatology practice.

Biopsy↗
PubMed1989

Interaction between cortisol and microbial proteases.

Binding (or interaction) of cortisol with microbial molecule(s) was observed by employing Bio-Gel HTP affinity chromatography and subsequently by fluorescence spectrophotometry. Molecule(s) in the crude extract of baker's yeast and in other microbial proteases exhibited varied degrees of cortisol-binding. Bacterial protease (type IX) had highest, while the type XXVI enzyme had the lowest, binding capacity. In addition, these two proteases exhibited a distinct difference in the alterations of ultraviolet spectra due to interaction with cortisol. Using casein as a substrate, cortisol, CTP, trypsin inhibitor or leupeptin appreciably inhibited type IX protease at low concentrations of Ca2+. However, thyroxine had no effect on this protease.

Bacteria↗
PubMed1989

Effect of dietary ascorbic acid on levels of serum mineral nutrients in guinea pigs.

The effect of dietary ascorbic acid on the serum mineral nutrients, Ca, Cu, Fe, K, Mg, Mn, Na and Zn in guinea pigs has been studied. Large amounts of ascorbic acid were administered to experimental animals in their drinking water. The daily ascorbic acid intake from the diet for the control animals was 10 mg/kg body weight. The mean ascorbic acid intakes for the two groups of experimental animals were 366 (37 times control) and 722 (72 times control) mg/kg body weight/day. In the ascorbic acid-treated animals, there was a significant increase in serum ascorbic acid levels in comparison with the controls. No substantial differences were observed in the body weights. The large quantities of dietary ascorbic acid did not influence serum levels of all eight minerals studied when the experimental and control values were compared using the two-tailed Student's t-test. However, serum level of copper in the guinea pigs ingesting a daily dose of 722 mg of ascorbic acid per kg body weight was slightly below control value when one-tailed Student's t-test was used.

Animals↗
PubMed1988

Subunit structure of high molecular weight mouse nerve growth factor.

Studies from several laboratories have shown that mouse submandibular glands and mouse saliva contain nerve growth factor (NGF) as part of a high molecular weight oligomeric macromolecule composed of three different subunits, termed alpha, beta, and gamma. The beta-subunit is the nerve growth-promoting protein. The gamma-subunit is a serine protease class enzyme of highly restricted substrate specificity. The alpha-subunit has no known function. This high molecular weight form of nerve growth factor is also a Zn(II)-containing metalloprotein. In the present study, measurements of multiple physicochemical parameters have been used to deduce the subunit structure of high molecular weight NGF. Results demonstrate that it contains two alpha-, one beta- and one gamma-subunit together with one tightly bound Zn(II) ion per molecule.

Animals↗
PubMed1988

Stability of morphine solutions in plastic syringes determined by reversed-phase ion-pair liquid chromatography.

A reversed-phase ion-pair HPLC assay has been developed for quantitating morphine, codeine, apomorphine, and pseudomorphine in aqueous solutions. Using two types of plastic syringes, the effect of light (25 W) and temperature (22 and 3 degrees C) on the stability of morphine, over a 12-week period, has been investigated in the presence and absence of preservative and antioxidant. The leaching of contaminants from the plastic syringes to water stored in them, for a period of up to 12 weeks, has also been investigated. The results indicate that less than 3% of the morphine is degraded in both types of plastic syringes, stored in light at 22 +/- 2 degrees C. The degradation is even less prominent in the dark or at 3 degrees C. Pseudomorphine has been identified as the major degradation product. Using 5% degradation of drug as the criterion for the determination of the shelf-life of morphine, it was found that in one brand of plastic syringes, morphine has a shelf-life of the order of 20 and 33 weeks, in the absence and presence of preservative and antioxidant, respectively. In the other brand of plastic syringe, the drug has a shelf-life of greater than 1 year. Some unidentified leached contaminants have been detected in water stored in both brands of syringes.

Apomorphine↗
PubMed1988

Acute volume loading studied in cat myocardium with 31P nuclear magnetic resonance.

To study the effects of acute volume loading on myocardial metabolic and mechanical function, seven cats were volume loaded via anastomosis of the abdominal aorta to the vena cava (AV shunt). Metabolic effects were evaluated with 31P nuclear magnetic resonance (NMR). Mechanical function was evaluated with heart rate X systolic blood pressure product (HR X SBP). Shunts were opened for 1-2 h during which time phosphocreatine (PCr), adenosine triphosphate (ATP), inorganic phosphate (Pi), and HR X SBP were monitored. High-energy phosphate energetics as determined by Pi/PCr and PCr/ATP ratios were correlated with HR X SBP. Opening of the AV shunts was associated with an increase (four cats) or a decrease (three cats) in HR X SBP. Pi/PCr ratios increased and PCr/ATP ratios decreased in cats with an increase in HR X SBP. In cats with a decrease in HR X SBP, Pi/PCr and PCr/ATP generally did not change significantly. In summary, acute volume loading could be associated with an increase or decrease in myocardial external work as evaluated by HR X SBP, accompanied by metabolic changes suggestive of appropriate induction of state 3 metabolism (active metabolic state: ADP + Pi----ATP) in those cats with increased mechanical work, and minimal change in bioenergetics in cats with no or minimal increase in mechanical work. These induced metabolic responses to myocardial mechanical loading can be evaluated with 31P NMR techniques and may provide insight into in vivo metabolic control mechanisms.

Adenosine Triphosphate↗
PubMed1988

Isolation and characterization of monoclonal antibodies against the adenovirus core proteins.

Monoclonal antibodies have been prepared that recognize adenovirus core proteins V, VII, and mu in ELISA and Western blot assays. Antibodies produced by all of 87 positive hybridoma colonies obtained from a mouse injected with the precursor to protein VII, pVII, produced antibodies that also reacted with purified protein VII in an ELISA assay and all tested recognized denatured protein VII immobilized on nitrocellulose. Such failure to recover antibodies that specifically recognized only protein pVII suggests that epitopes common to the 174 amino acid protein VII and its 197 amino acid precursor were more effective antigenic determinants than the N-terminal 23 amino acid segment unique to pVII. All antibodies raised against protein mu cross-reacted with protein VII in both assays, but only a small fraction of the anti-protein VII or pVII antibodies recognized protein mu. Such cross-reactivity is discussed in relation to an unusual, arginine-rich sequence present in both protein VII and protein mu.

Adenoviruses, Human↗
PubMed1988

The Minnesota Arthritis Training Program: emphasis on self-management, not compliance.

Based on a needs assessment of our ambulatory patients and review of available arthritis education programs, we developed an innovative education and exercise program, the Minnesota Arthritis Training Program (MATP). Patients are taught self-management skills including how to: (1) interpret changing physical symptoms and limitations caused by joint inflammation and apply modifications to their individualized exercise program; (2) recognize common drug toxicites and use a decision analysis schema to manage side effects to decrease the risk of serious toxicity and decrease dependency on professionals safely; (3) develop strategies to modify activity schedules to make the most of limited stamina; (4) recognize and understand psychological problems produced by rheumatoid arthritis (RA) including sexual dysfunction, depression and breakdown of communication; and (5) reconstitute social support systems.

Arthritis, Rheumatoid↗
PubMed1988

Comparison of time-resolved and -unresolved measurements of deoxyhemoglobin in brain.

Continuous (CW) and pulsed light were used for the noninvasive measurement of hemoglobin oxygenation in tissues. A dual wavelength method of continuous illumination spectroscopy used 760 nm (deoxyhemoglobin peak) and 800 nm (an oxyhemoglobin-deoxyhemoglobin isosbestic point) to measure the kinetics and extent of oxyhemoglobin deoxygenation in brains during mild ischemia/hypoxia. Absorption and scattering were modeled in an artificial milk/yeast blood system, which gave an exponential relationship between absorption and optical path length to a depth of 7 cm. Time-resolved spectroscopy (10-ps resolution) afforded a display of the times and distances of arrival of photons emitted by the cat brain in response to a 10-ps input pulse. The emitted photons rose to a peak in a fraction of a nanosecond and declined exponentially over a few nanoseconds. The half-time of exponential decay corresponds to photon migration over a distance of 4 cm. Exponential light emission continued for several more nanoseconds when the brain was encased by the skull, which plays a key role in prolonging light emission. The exponential decline of light intensity has a value [exp(-microL)], where L is the path length determined from the time/distance scale and mu is the characteristic of the migration of light in the brain. The factor mu is increased by increasing absorption, and mu' = epsilon C where epsilon and C are the Beer-Lambert parameters of extinction coefficient (epsilon) and concentration (C). Thus, deoxyhemoglobin can be quantified in brain tissues.

Animals↗
PubMed1988

Acceptance of hospital-based respite care by families and elders.

Health and social service professionals generally view respite services as a preventive health care measure for both caregiver and recipient. However, many families with dependent elders are reluctant to use formal respite care services. Factors associated with family member perceptions of hospital-based respite care as a viable personal option are examined. The findings suggest that families often fail to recognize the preventive health care functions that respite care may offer and that practitioners should propose respite care as part of overall treatment plans.

Aged↗
PubMed1988

Restriction endonucleases in Clostridium pasteurianum ATCC 6013 and C. thermohydrosulfuricum DSM 568.

A small collection of clostridia was surveyed for type II restriction endonucleases. Enzymes were detected in two organisms. Clostridium pasteurianum ATCC 6013 contains an isoschizomer of ThaI (FnuDII) [5'-CGCG-3'] and preliminary evidence suggests that cleavage generates blunt-ended fragments. Clostridium thermohydrosulfuricum DSM 568 contains an isoschizomer of MboI (Sau3A) [5'-GATC-3'] that is inactive on dam methylated substrates. The DNA of this latter organism shows dam methylation.

Clostridium↗