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Biomedical subjects

P Burns

Publications and source records attributed to P Burns.

At least 19 recordsLinked to original sources
PubMed1992

Experimental changes in mineral content of juvenile mouse femora.

Juvenile laboratory mice were exposed to hypergravity (8 g), burrowing exercise, swimming to exhaustion, an anabolic steroid, and swimming and an anabolic steroid for 30 days to determine the variability of skeletal mineralization during growth. Changes in mineralization were correlated with changes in bending strength. Experimental mouse femora were loaded to failure in a cantilever beam configuration to determine bending strength, and ashed to determine total mineral content. Between experimental groups, mineral content ranged from 66.0 to 71.2% with the greatest change from the control being a 4.7% decrease in mineralization in the male swimming exercise group (P less than 0.001). Within two age-matched experiments, the first showed that the group with the greatest decrease in mineralization also had the greatest reduction in bending strength (P less than 0.001). The second age-matched experiment showed that the group with the greatest reduction in mineralization had bending strength greatly reduced (P less than 0.001). However, in this experiment, the weakest femora were in the anabolic steroid group that did not have the mineral content reduced. We conclude that (1) mineralization of juvenile mouse femora is extremely variable given varied conditions of exercise or loading; (2) mineralization of normal bone is decreased more often and to a greater extent than increased from normal exercise controls; (3) the decrease in mineralization seen here can decrease bending strength; and (4) the decrease in mineralization seen was not caused by a decrease in a mechanical loading but was probably due to a corticosterone-mediated psychological stress response.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Effect of (S)-1-[(3-hydroxy-2-phosphonyl methoxy) propyl] cytosine on the replication and morphogenesis of herpes simplex virus type 1.

Treatment of African green monkey kidney cells with 1 microgram/ml of (S)-1-[(3-hydroxy-2-phosphonyl methoxy) propyl] cytosine (HPMPC) inhibited the release of infectious herpes simplex virus type 1 (HSV-1) by more than 90%. Electron microscopic observations of HPMPC-treated monkey kidney cells demonstrated few intracellular or extracellular viral particles. The viral particles seen were without dense cores. In addition, HPMPC blocked cell fusion induced by HSV-1 in monkey kidney cells. Immunoblot analysis showed that HPMPC significantly blocked the expression of HSV-1-specific proteins. Furthermore, HPMPC inhibited the synthesis of viral DNA as determined by in situ hybridization. These results indicate that HPMPC inhibits the replication of HSV by blocking one of the events involved in DNA synthesis.

Animals↗
PubMed1990

Expression of herpes simplex virus type 1 glycoproteins in interferon-treated human neuroblastoma cells.

Human alpha interferon (IFN) significantly inhibits the replication of herpes simplex virus type 1 in human neuroblastoma cells. This inhibitory effect can be blocked by pretreatment with antiserum to IFN. We observed no significant differences in the expression of major nucleocapsid proteins, including VP5, between IFN-treated and untreated neuroblastoma cells. Electron micrographs demonstrated that there were distinct viral nucleocapsids within IFN-treated neuroblastoma cells. The expression of glycoproteins B and E was significantly reduced in these IFN-treated cells. On the other hand, glycoprotein D, although reduced in quantity, was expressed after IFN treatment. An immunofluorescence assay of the IFN-treated and virus-infected cells detected glycoprotein D in the Golgi complexes and in the nuclear membranes. Our results indicate that human alpha IFN may be useful in the study of gene expression in IFN-treated cells of neuronal origin.

Capsid↗
PubMed1990

Color Doppler artifact in anechoic regions.

For color Doppler imaging, several types of signal processing are employed in order to produce acceptable images of blood flow in blood vessels while suppressing color in moving solid tissue. The processing can produce an artifact in which color may arise from noise or from tissue motion and fill anechoic regions preferentially. This artifact may complicate the differentiation of areas with blood flow from anechoic regions without flow. By using four different color Doppler ultrasound units to image a tissue-equivalent phantom containing anechoic cylinders, artifactual color resulted when gain was raised sufficiently. This color was concentrated in anechoic regions of a gray-scale image that did not contain flow. In two instruments, this artifact was only observed when the transducer was vibrated, simulating tissue motion. In these instruments, the identification of low-frequency, high-amplitude Doppler signals is used to locate moving solid tissue and so suppress color in these regions. In the other two instruments, the presence of echoes within the image suppressed the assignment of color. With both types of processing, color may appear artifactually in echo-free regions without flow, such as fluid collections. Presence or absence of flow should be confirmed by Doppler spectral analysis. An understanding of the origin and appearance of artifactual color can prevent its occurrence from detracting from the usefulness of color Doppler imaging.

Aorta, Abdominal↗
PubMed1990

Acute blood pressure elevation can mimic arteriographic appearance of cerebral vasculitis--(a postpartum case with relative hypertension).

A 35-year-old woman presented 9 days postpartum with severe headache, arterial hypertension, and left parietal symptoms. A cerebral angiogram revealed widespread irregular areas of narrowing and dilatation, highly suggestive of vasculitis. The hypertension was treated successfully. A repeat angiogram 9 days later was almost completely normal. As this course is inconsistent with isolated cerebral vasculitis, and because the angiogram normalized with antihypertensive therapy, it is likely that the angiographic findings were secondary to hypertension. Experimental data in fact show that acute hypertension can produce areas of cerebrovascular spasm and dilatation. Recognition that angiographic findings suggestive of cerebral vasculitis are nonspecific and may be due to hypertension should prevent unnecessary treatment for vasculitis in such patients.

Acute Disease↗
PubMed1989

Serum bioactive lactogenic hormone levels in women with familial breast cancer and their relatives.

Serum levels of bioactive lactogenic hormone (BLH), immunoreactive prolactin and growth hormone (ir-PRL and ir-GH) were measured in a group of familial breast cancer patients and their first degree female relatives and compared to those found in normal healthy women. The ratio of BLH to the sum of ir-PRL and ir-GH was slightly but significantly decreased in the familial breast cancer group (P = 0.018 by the Mann-Whitney U test) although there were no significant differences in the levels of BLH, ir-PRL and ir-GH between the two groups. No differences in the levels of the lactogenic hormones could be detected when the pre-menopausal women were considered separately or when 20 women from the familial group were compared to normal controls matched for age, parity, weight and menopausal status. The levels of BLH were highly correlated with the sum of ir-PRL and ir-GH in both the familial breast cancer group and the controls (P less than 0.001 for both groups by Spearman's rank correlation test). These findings are not indicative of the presence of an additional species of bioactive, but not immunoreactive, lactogen in the sera of women with or at high risk of breast cancer. However, the presence of different, but equipotent, forms of lactogen cannot be excluded in these women.

Adolescent↗
PubMed1988

Effects of nicotine on platelet function.

In non-smokers, only high concentrations of nicotine (10 mM) caused platelet aggregation in platelet-rich plasma and release of 5-hydroxytryptamine (5-HT). Both responses to ADP and 5-HT were enhanced at 1 and 10 mM nicotine while they were inhibited to collagen, ristocetin, adrenaline and arachidonic acid. Lower concentrations of nicotine had no effect with any agent other than 5-HT, with which a variable enhancement of 5-HT-induced aggregation was observed. Uptake of 14C-5-HT was inhibited by nicotine at 100 microM or higher while platelet factor 3 availability was unaffected. Thus it is unlikely that direct effects of nicotine on platelets are responsible for smoking-related changes in platelet reactivity.

Humans↗
PubMed1986

Acoustical analysis of the underlying voice differences between two groups of professional singers: opera and country and western.

An acoustical analysis of the speaking and singing voices of two types of professional singers was conducted. The vowels /i/, /a/, and /o/ were spoken and sung ten times each by seven opera and seven country and western singers. Vowel spectra were derived by computer software techniques allowing quantitative assessment of formant structure (F1-F4), relative amplitude of resonance peaks (F1-F4), fundamental frequency, and harmonic high frequency energy. Formant analysis was the most effective parameter differentiating the two groups. Only opera singers lowered their fourth formant creating a wide-band resonance area (approximately 2,800 Hz) corresponding to the well-known "singing formant." Country and western singers revealed similar resonatory voice characteristics for both spoken and sung output. These results implicate faulty vocal technique in country and western singers as a contributory reason for vocal abuse/fatigue.

Computers↗
PubMed1984

The effects of acute smoking on platelet behaviour, fibrinolysis and haemorheology in habitual smokers.

There is an increased frequency of arterial thrombosis in cigarette smokers. The changes in blood coagulation seen in these subjects have been studied by many workers but results have not always been in agreement. We wished to study the effects of acute smoking on platelet behaviour, fibrinolysis and haemorheology in ten habitual smokers, and to compare these results with non-smoking controls. Results show that the smoking group had higher plasma fibrinogen (p less than 0.04), lower plasminogen (p less than 0.02) and plasminogen activator (p less than 0.05), and higher plasma viscosity (p less than 0.003). The changes seen in cigarette smokers after smoking three cigarettes were an increase in the rate of platelet aggregation to ADP (p less than 0.02), an increase in alpha 2M, (p less than 0.02), and factor VIII RAG (p less than 0.05). Plasma viscosity was decreased (p less than 0.02) as was red cell deformability (p less than 0.02). We confirm an increased tendency to hypercoagulability in smokers compared to controls which becomes more pronounced immediately after smoking three cigarettes.

Adult↗
PubMed1984

A double-blind trial of intramuscular stanozolol in the prevention of postoperative deep vein thrombosis following elective abdominal surgery.

Fibrinolytic shutdown may be important in the development of postoperative deep vein thrombosis (DVT). We have previously shown that stanozolol 50 mg, given intramuscularly 24 hr before surgery, prevents the decrease in plasminogen activator activity (PA) seen on the first postoperative day in patients at high risk of DVT. To investigate the role of fibrinolytic shutdown in causation of DVT, sixty patients were randomized in a double-blind controlled trial to receive stanozolol or placebo intramuscularly, and DVT was detected by leg scanning and confirmed by venography. Scan positive DVT occurred in 11 of 31 placebo patients (35%) and 12 of 29 who received stanozolol (41%). A significant decrease in PA was confirmed in the placebo group, while stanozolol caused a significant increase in PA on the first postoperative day. Patients in either group who did not develop DVT showed minimal changes in PA. We conclude that prevention of fibrinolytic shutdown by this regimen of stanozolol does not prevent postoperative DVT, and that further studies are required to clarify the relationship of postoperative fibrinolysis and DVT.

Abdomen↗
PubMed1984

Effects of diabetic control and biosynthetic human insulin on blood rheology in established diabetics.

Blood rheology (blood viscosity, haematocrit, plasma viscosity, erythrocyte sedimentation and deformability) was measured in 22 diabetics in a study to compare animal insulins with biosynthetic human insulin. All rheological variables were significantly abnormal in the diabetics when compared with matched normal controls, and were not influenced by the type of insulin injected. However, blood rheology was related to diabetic control, as judged by glycosylated haemoglobin levels; when diabetic control was worst (mean glycosylated haemoglobin 11%), blood viscosity was significantly higher and red cell deformability significantly lower than when control was at its best (mean glycosylated haemoglobin 9.5%). A similar correlation between mean red cell deformability and mean glycosylated haemoglobin was found when individual diabetics were compared (r = 0.66; p less than 0.001). The occurrence of abnormal blood viscosity and red cell deformability during periods of poor diabetic control may contribute to the development of diabetic vascular complications.

Adolescent↗
PubMed1983

Results of computerized tomography, psychometric testing and dietary studies in social drinkers, with emphasis on reversibility after abstinence.

The frequency of abnormal results of cranial computerized tomography (CT), psychometric testing and dietary studies was established in a prospective study of 39 light-to-moderate drinkers (below 120 g/day) of both sexes. Thirty-one subjects showed some degree of cerebral atrophy on CT scan and, of these, 25 also showed abnormalities on psychometric testing. Psychometric deficits were found in three subjects with a normal CT scan. Cerebral atrophy was reversed in 10 of 11 subjects who abstained from alcohol for between three and 12 months. On re-examination after six months, five of the 11 subjects showed improved performance in most psychometric tests. Sixteen subjects were deficient in some dietary factor and all but one of these had abnormal results of CT scan or psychometric testing. The deficiencies found were in kilojoules (six subjects), iron (five subjects), protein (four subjects), calcium (seven subjects), thiamin (six subjects), and ascorbic acid (one subject). Eight subjects had multiple dietary deficiencies; all but one were women. Four had a low red blood cell level of thiamin, but normal serum levels. This was thought to reflect an impairment in the metabolism of this vitamin due to the effect of alcohol. All four subjects with a low red blood cell thiamin level were found to have cerebral atrophy on CT scan and two had psychometric deficits.

Adolescent↗
PubMed1983

Comparison of home hemodialysis to continuous ambulatory peritoneal dialysis.

We evaluated prospectively various outcome measurements of patients assigned initially to continuous ambulatory peritoneal dialysis (CAPD) and home hemodialysis (HHD) from February 1979 to August 1981 and the causes for failures of the techniques. Morbidity was assessed by time in hospital/time on dialysis. Fifty-six patients were trained for CAPD and 37 for HHD. Those assigned to CAPD experienced an increased frequency of hospitalization (7.5% CAPD, 2.8% HHD, respectively) primarily due to episodes of peritonitis. There was also a higher modality failure rate (43% vs. 16%). However, the groups were not comparable in all respects. For example, the CAPD population included 21 patients with major cardiovascular diseases versus only three in the HHD group. The demographic characteristics of both populations including race, sex, age, income, place of residence, marital status, and education were similar. At the time of this study there is no direct evidence showing that healthy patients otherwise able to perform HHD may be maintained with less morbidity for a prolonged period utilizing CAPD. Therefore, we suggest that HHD is the home method of choice for patients able to proceed with this technique. CAPD may be indicated for patients in whom the period of home dialysis is expected to be relatively short and who would be otherwise unable to carry out home dialysis, for example, patients awaiting transplantation and those unable to be maintained on hemodialysis because of impaired cardiac function. To fully evaluate CAPD as a long-term maintenance therapy, a prospective trial must be performed.

Adult↗