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Biomedical subjects

P Hall

Publications and source records attributed to P Hall.

At least 181 records · Page 10Linked to original sources
PubMed1990

Computerized measurement of iron in liver biopsies: a comparison with biochemical iron measurement.

The measurement of stainable hepatic iron using a microcomputer image analysis system was compared with standard biochemical measurements of liver iron content in 103 liver biopsy specimens--29 of idiopathic hemochromatosis, 51 of alcoholic liver disease and 23 of various nonalcoholic liver diseases. Sections were stained using Perls' method for iron; the mean area staining positively for iron was measured and expressed as a percentage of the area of biopsy measured. Biochemical (biochemical hepatic iron [mumol/gm dry wt]/age) and morphometrical (morphometrical hepatic iron [%]/age x 100) hepatic iron indices were calculated. Patients in the idiopathic hemochromatosis group had significantly higher biochemical hepatic iron concentrations (p less than 0.001) compared with the alcoholic liver disease and nonalcoholic liver disease groups: 284 (range = 119 to 631), 21 (range = 2 to 65) and 15 (range = 3 to 31) mumol/gm dry wt, respectively. The biochemical hepatic iron index was also significantly higher (p less than 0.001) in the hemochromatosis group compared with the alcoholic liver disease and nonalcoholic liver disease groups: 5.8 (range = 2.1 to 13.7), 0.4 (range = 0 to 1.6) and 0.4 (range = 0 to 1.1), respectively. Computerized measurements were significantly higher in the hemochromatosis group (p less than 0.001) compared with the alcoholic liver disease and nonalcoholic liver disease groups: 9.72% (range = 1.50% to 29.26%), 0.13% (range = 0% to 1.20%) and 0.03% (range = 0% to 0.40%), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1990

Prospective evaluation of serum CA 125 levels in a normal population, phase I: the specificities of single and serial determinations in testing for ovarian cancer.

To determine the potential efficacy of the CA 125 assay as one component of a strategy for early detection of ovarian malignancy, serum CA 125 levels were determined in 1082 women 40 years of age or older in Stockholm. Initial serum CA 125 levels exceeded 35 U/ml in 36 women (3.3%) and 65 U/ml in 11 women (1.0%), placing the exact 95% upper confidence limits on false positive rates for a single screen at 4.3 and 1.7%, respectively. Follow-up CA 125 levels were obtained for those women with initially elevated levels and a group of age-matched controls. Mean CA 125 levels declined significantly for women with initially elevated levels (P = 0.0014). Interindividual variation and variation within individual subjects over the entire follow-up period were 52 and 35%, respectively. Of the 36 subjects with initially elevated serum CA 125 levels, only 2 showed a doubling of these levels; in only 1 of these 2 was this increase sustained. Intensive clinical follow-up with pelvic examination and ultrasonography, with investigators blinded to CA 125 results, led to the diagnosis of Stage III ovarian cancer in the latter individual. Diagnosis was made 21 months after the initially elevated serum CA 125 measurement and 15 months after the first measured doubling of that level. Because no other malignancies were identified at entry or during the follow-up period (median 560 days) in the women with elevated CA 125 levels, the specificity of the assay over that time period would have been 99.9% using the doubling of an initially elevated value as the criterion for determining positivity and 100% using as the criterion a sustained increase in level for those with initially elevated levels that doubled. These results support the continued investigation of longitudinally collected CA 125 levels to identify individuals at high risk for ovarian malignancy.

Adult↗
PubMed1990

Head and neck cancer: detection and therapeutics.

The stage of disease remains the major prognostic indicator for head and neck cancer. Five-year survival declines as the disease stage progresses. Currently, only stage I and stage II head and neck cancers are curable; thus, early detection is imperative. Treatment for stage III and stage IV disease is only palliative. Pharmacists can promote early detection by educating high-risk populations (patients who drink and smoke) and monitoring their use of nonprescription medications for palliation of symptoms. Patients with risk factors and symptomatology of head and neck cancer should be referred for proper medical evaluation. Thus, through education and communication, pharmacists can play an important role in the early detection and treatment of head and neck cancers.

Head and Neck Neoplasms↗
PubMed1990

Quantification of changes in serotonin uptake with spinal cord injury.

The high-affinity uptake of [3H]serotonin was studied using spinal cord preparations obtained from normal dogs, dogs made paraplegic by midthoracic transection, and dogs made monoplegic by midthoracic hemisection. Measurements were made at 1, 4, and 8 weeks after surgery. Lumbar spinal cord was removed at the above time periods and a myelin-free synaptosomal fraction was obtained by centrifugation and used for studying high-affinity serotonin uptake. At 1 week, there were no significant differences for Km values (nM) among any of the three groups (138 +/- 20, 128 +/- 22, and 118 +/- 20). The Vmax values (pmol/min/mg of protein) at 1 week for the control group (4.9 +/- 0.6) versus the hemisected group (4.3 +/- 0.7) were not significantly different. The Vmax values at 1 week for the completely transected group (2.3 +/- 0.3; P less than 0.01) were significantly reduced by 53 +/- 7%. At 4 weeks, the Vmax values for the hemisected (1.8 +/- 0.2; P less than 0.05) and transected groups (0.6 +/- 0.2; P less than 0.05) were significantly different as compared to the control group. The mean percent drop in Vmax after hemisection was 56 +/- 4%, close to the predicted value of 50%. The mean percent drop in Vmax after transection was 86 +/- 2%. At 8 weeks the mean Vmax values for the hemisected (1.9 +/- 0.3; P less than 0.05) and transected (0.4 +/- 0.4; P less than 0.05) groups were not significantly different compared to their respective 4-week values. It appears that serotonin uptake can be used to quantitate roughly the degree of spinal cord injury.

Animals↗
PubMed1990

Second primary tumors following thyroid cancer. A Swedish record-linkage study.

The incidence of second primary tumors was studied through record-linkage in 2,968 thyroid cancer patients reported to the Swedish Cancer Registry during the period 1958-1975. The cohort was matched with the Swedish Cancer Registry between 1959 and 1984. A total of 283 second primary tumors were reported more than one year after thyroid cancer diagnosis, and the standardized incidence ratio (SIR) was 1.18 (95% confidence interval = 1.03-1.31). A significant elevated risk of cancer of the kidney, endocrine glands, and nervous system was noted. Men had a higher risk (SIR = 1.37; 95% CI = 1.06-1.70) than women (SIR = 1.11; 95% CI = 0.96-1.28). Patients who were 36-45 years at the time of the thyroid cancer diagnosis were at highest risk of developing a second primary tumor (SIR = 1.35; 95% CI = 0.99-1.81). Significantly elevated risks were seen 5-9 years after the thyroid cancer diagnosis (SIR = 1.44; 95% CI = 1:14-1.69), and the SIR was close to unity after greater than or equal to 15 years of followup. Previously described elevated risks of subsequent leukemia and breast cancer were not confirmed in this study. Close medical surveillance, thyroid cancer treatment, hereditary factors, and a high frequency of autopsy could all contribute to the elevated risk of a second primary tumor in these patients.

Adolescent↗
PubMed1989

Prevalence of genetic haemochromatosis among diabetic patients.

Since diabetes mellitus is a frequent manifestation of haemochromatosis the prevalence of the disease was investigated in 418 patients attending a diabetic clinic. 21 (5%) patients had a persistently high serum ferritin (men, over 400 micrograms/l; women, over 300 micrograms/l) and 5 of these had transferrin saturations consistently over 55%. Idiopathic haemochromatosis was confirmed by liver biopsy in 4 patients, all of whom had a hepatic iron index greater than 2.0. The prevalence rate of previously unrecognised idiopathic haemochromatosis was thus 9.6 per 1000 (general population prevalence 1 in 250), suggesting that screening of diabetic patients for this genetic disease may be more cost-effective than screening in the general population.

Adult↗
PubMed1989

Implantable catheter system for long-term intravenous chemotherapy.

Fifty-three implantable catheter systems (Port-A-Cath) were placed subcutaneously in 48 patients with malignant tumours. This device consists of a stainless steel chamber covered by a silicone membrane connected to a silicone catheter placed in a central vein. All systems were used for administration of chemotherapy. The mean function time was 187 days (range 0-867). Complications necessitating reoperation occurred in six patients. In three cases, the catheter occluded from thromboses. In two patients, wound dehiscence occurred, and in one a wound infection developed. In one case, the catheter was disconnected from the port. Four patients who had had the port removed later received new ports. One patient had the second port removed and was given a third catheter system. It is concluded that subcutaneously implantable injection ports constitute a safe and convenient access for long-term intravenous chemotherapy. The complication rate is low, and it should be possible to avoid most recorded complications in the future.

Adolescent↗
PubMed1989

Peripheral neuropathy associated with Castleman's disease.

Four patients with polyneuropathy complicating the plasma cell variant of Castleman's disease (angiofollicular lymph node hyperplasia) are described. The neuropathy was predominantly motor and severely disabling. Vasculopathy, papilloedema, organomegaly, endocrinopathy, oedema and paraproteinaemia were variably present in these patients. Sural nerve biopsy showed changes of both demyelination and axonal loss. Capillary proliferation and endothelial hypertrophy in the epineurium and endoneurium, similar to that seen in affected lymph nodes, suggested that a diffuse vasculopathy may contribute to the neuropathy. Serum antibody activity against a variety of neural antigen preparations was not detected in any of the patients. Two untreated patients died. Substantial improvement in the neuropathy occurred in the two patients treated with cyclophosphamide and prednisolone.

Adult↗
PubMed1989

Increased exercise capacity after digoxin administration in patients with heart failure.

Failure to objectively assess the effect of digitalis on exercise capacity has resulted in controversy regarding its use in patients with chronic congestive heart failure. To clarify this situation, maximal treadmill testing with respiratory gas exchange analysis was performed on 11 patients (mean age 57 +/- 9 years) with chronic congestive heart failure with and without digoxin therapy. Ten of the 11 had a consistent third sound gallop, and the mean ejection fraction of the group was 24 +/- 10%. Rest heart rate was significantly higher (91 +/- 16 versus 102 +/- 16 beats/min; p less than 0.05) and rest systolic blood pressure was significantly reduced in the absence of digoxin (130 +/- 23 versus 121 +/- 15 mm Hg; p less than 0.05). No differences in heart rate or blood pressure were observed during exercise. Significant increases in ventilatory oxygen uptake were observed with digoxin submaximally (3.0 mph, 0% grade), at the gas exchange anaerobic threshold and at maximal exercise (mean increase of 2.6 ml/kg per min; p less than 0.02). An improvement in the estimated ratio of ventilatory dead space to tidal volume (VD/VT), an index of physiologic efficiency, occurred throughout exercise during digoxin therapy, and there was a significant negative correlation between the change in maximal oxygen uptake and change in maximal estimated VD/VT (r = -0.63; p less than 0.05). Thus, digoxin therapy is associated with a significant improvement in exercise capacity in patients with chronic heart failure, most likely due to an improved matching of ventilation to perfusion.

Adult↗
PubMed1989

Effect of captopril on urinary cystine excretion in homozygous cystinuria.

We determined if captopril could reduce urinary cystine excretion in homozygous cystinuric patients. Seven patients were treated with 150 mg. captopril daily after determination of baseline 24-hour urine cystine excretion. All patients had a history of multiple cystine stones, and were on chronic fluid and alkalization therapy. Five patients had previously been on D-penicillamine. Cystine excretion studies were repeated 1 to 5 months after institution of captopril. Baseline 24-hour urinary cystine excretion ranged from 580 to 970 mg. per gm. creatinine (mean 744). After institution of captopril these levels decreased to a range of 113 to 581 mg. per gm. creatinine (mean 371). These values on treatment represented a statistically significant decrease to between 18 and 89% of baseline levels (p equals 0.0045). We conclude that captopril can significantly, and at times profoundly, decrease urinary cystine excretion in patients with homozygous cystinuria. Further studies are required to elucidate fully the mechanism of urinary cystine reduction and to help define a possible role for this drug in routine maintenance or dissolution therapy.

Adult↗
PubMed1989

Prescription of aerobic exercise during pregnancy.

Available evidence supports the existence of both risks and benefits of aerobic conditioning during human pregnancy. During intensive exertion, maternal skeletal muscle and the fetus may compete for blood flow, oxygen delivery and essential fuel substrates. Hence, the most important hypothetical risks include acute fetal hypoxia, hyperthermia and malnutrition. If exercise is repeated on a chronic basis, teratogenic effects, fetal growth retardation or altered fetal development may result if maternal/fetal adaptive reserve is exceeded. A dose-response relationship for such effects has been demonstrated in laboratory animals, but specific findings may have limited applicability to voluntary exercise in pregnant women. Although further investigation is needed, the majority of published studies suggest that fitness-type conditioning does not jeopardise fetal well-being in healthy well-nourished women. Benefits of such exercise appear to include increases in maximal aerobic power (VO2max, L/min) and enhanced cardiopulmonary reserve. It has also been proposed that exercise prevents accumulation of excess body fat, promotes psychological well-being, helps to prevent gestational diabetes and low back pain and may facilitate labour. However, these benefits remain to be confirmed by objective scientific study. Due primarily to a lack of scientific data, existing medical guidelines for exercise during pregnancy are conservative and follow a common sense approach. Good agreement exists on the need for preparticipation medical screening and continuing surveillance to verify the existence of maternal/fetal adaptive reserve. Women are advised to select safe, non-ballistic exercise modalities and to avoid thermal or hyperbaric environmental stress during exercise. Exercise in the supine position is also prudent to avoid, particularly in late gestation. The usefulness of heart rate in prescribing and monitoring exercise intensity has been questioned, with use of conventional perception of exertion scales being the most logical alternative. Prediction of maximal aerobic power (VO2max) from submaximal work rate/heart rate relationships is also problematic during pregnancy. Other areas of debate include the advisability of initiating a new exercise programme during pregnancy, methods for prevention of fetal hyperthermia, the safety of weight-training/isometric exercise and optimal methods for training of pre/postnatal fitness instructors.

Exercise Therapy↗
PubMed1989

Protocol for the evaluation of automated blood coagulation instruments (coagulometers) for determination of the international normalised ratio.

Results of prothrombin time tests for the control of oral anticoagulant therapy, when using automated blood coagulation instruments (coagulometers), may not be the same as those obtained when using manual methods, and variation in coagulometer performance may affect clinical interpretation of data. The haematology advisory committee of the Institute of Medical Laboratory Sciences has recommended that coagulometers should be used for determination of prothrombin times only if it can be demonstrated that the results are valid when compared with those of a standardised manual method. A protocol for the evaluation of coagulometers, and details of the procedures, are given in this report, the main emphasis of which is on the assessment of instruments for determination of the International Normalised Ratio. Guidelines are also provided for the general use of machines of this type and for the assessment of safety. The principles of the protocol are applicable to other automated tests of blood coagulation.

Autoanalysis↗
PubMed1988

High-frequency electrocardiography: an evaluation of lead placement and measurements.

Before there is widespread clinical application of the high-frequency ECG, differences resulting from the leads used and the measurement criteria for late potentials must be resolved. Therefore 113 consecutive patients without resting QRS conduction abnormalities referred for Holter monitoring were studied. Four different lead systems were used: a standard bipolar orthogonal lead system and three bipolar lead systems mapping the left ventricle. Measurements made of late potentials included normal and high-frequency QRS duration, their difference, the duration of low-amplitude signals (less than 40 uV) in the terminal QRS, and the root mean square of the last 40 msec of the high-frequency QRS duration. We found that the left ventricular leads tended to give more abnormal measurements than the orthogonal system and that the various measurements failed to agree with each other. In addition, even in this population in which abnormalities of QRS conduction were excluded, the late potential measurements tended to be more abnormal as QRS duration lengthened. These differences in lead systems and measurement criteria must be considered when clinically applying information regarding late potentials measured from the high-frequency ECG.

Adult↗
PubMed1988

Virus-liver cell interactions in duck hepatitis B virus infection. A study of virus dissemination within the liver.

Thirty-five 1-day-old Pekin-Aylesbury ducks were inoculated intravenously or intraperitoneally with duck hepatitis B virus, and the time-course of infection was examined by Southern-blot, dot-blot, and in situ hybridization and by immunohistochemistry. Randomly scattered single infected hepatocytes were first seen on days 1 and 2 after inoculation and by day 3 occurred as single cells, pairs, and groups of 5-10 adjoining cells. From day 4 after inoculation all hepatocytes were positive for duck hepatitis B surface antigen and deoxyribonucleic acid. Duck hepatitis B virus deoxyribonucleic acid levels in liver extracts and serum increased logarithmically from days 2 to 3 to a plateau by days 4 to 5 after inoculation. Infected and control birds showed no significant differences during the first 7 days in terms of liver histology, hepatocyte morphology, or mitotic activity. It was concluded that (a) virus gains access to randomly distributed hepatocytes without first replicating in other cell types, and then begins disseminating to adjacent cells following anatomic boundaries; (b) markers of infection in liver and serum show reproducible kinetics, thus making this in vivo system amenable to further quantitative study; and (c) hepatocytes in this system are highly permissive to virus replication without the development of significant cytopathology.

Animals↗
PubMed1988

Endourologic management of upper and mid ureteral calculi: percutaneous antegrade extraction vs transurethral ureteroscopy.

Fifty patients requiring intervention for upper or mid ureteral calculi were managed initially with a percutaneous antegrade approach (25 patients) or a transurethral ureteroscopic approach (25 patients). In both groups, a crossover to the other modality was at times utilized to accomplish stone removal. Success for either group was defined as complete stone removal without the need for open intervention.

Endoscopy↗
PubMed1988

Maximal exercise testing and gas exchange in patients with chronic atrial fibrillation.

To evaluate the response of patients with chronic atrial fibrillation to exercise, 50 men (mean age 65 +/- 8 years) with atrial fibrillation underwent a maximal exercise test using respiratory gas exchange techniques. Patients were classified by the presence (n = 29) or absence ("lone atrial fibrillation," n = 21) of underlying heart disease. Responses were evaluated at a standard submaximal work load (3.0 mph, [4.8 km/h] 0% grade), at the gas exchange anaerobic threshold and at maximal exercise. For all 50 patients, the mean maximal oxygen uptake was 20.6 ml/kg per min, which approximates 85% of the aerobic capacity predicted for age-matched normal individuals. Patients with lone atrial fibrillation demonstrated normal exercise capacity in contrast to patients with atrial fibrillation and known heart disease (22.7 +/- 5 versus 19.1 +/- 5.0 ml/kg per min, p less than 0.05). The mean maximal heart rate (176 +/- 30 beats/min) was approximately 20 beats/min higher than that expected for age, was extremely variable and accounted for only 8% of the variance in maximal oxygen uptake. Maximal heart rate in subjects with lone atrial fibrillation was higher than that of subjects with atrial fibrillation and known heart disease (189 +/- 32 versus 166 +/- 24 beats/min, p less than 0.01). Stepwise regression analysis revealed that maximal systolic blood pressure accounted for 19% of the variance in maximal oxygen uptake (VO2 max), suggesting that systolic function is an important determinant of exercise performance in atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗