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Biomedical subjects

M Day

Publications and source records attributed to M Day.

At least 19 recordsLinked to original sources
PubMed1992

Autosomal dominant polycystic kidney disease with primary hyperaldosteronism.

We report three cases of primary aldosteronism associated with autosomal dominant polycystic kidney disease. The diagnosis of primary hyperaldosteronism was based on the presence of hypokalaemia with excessive urinary potassium excretion and/or the characteristic hormonal changes. Renal function impairment due to autosomal dominant polycystic kidney disease could mask hypokalaemia. The interpretation of adrenal imagery may be hindered by adjacent renal cysts. In one case an adrenal adenoma was detected and surgically removed, with only partial correction of the blood pressure. This could be explained by the persisting underlying autosomal dominant polycystic kidney disease. We conclude that in a hypertensive patient with polycystic kidney disease, extrarenal causes of hypertension may be present.

Adult↗
PubMed1992

[Treatment of hypertension in diabetes: threshold of intervention and therapeutic options].

Early screening for hypertension in diabetic patients and for glycoregulation abnormalities in hypertensives is justified by the additive cardiovascular risks when hypertension and diabetes co-exist and by the accelerated development of diabetic nephropathy and retinopathy if hypertension co-exists. In insulin-dependent diabetes, hypertension is generally preceded by microalbuminuria, known to be reduced by angiotensin converting enzyme inhibitors. The requirement for nephropathy prevention and the hemodynamic and/or tissular effects of this therapeutic class could justify their use at a blood pressure level less than that conventionally considered hypertensive. This strategy must be confirmed by prospective trials, already underway, evaluating the nephroprotective efficacy of this therapy. In non-insulin-dependent diabetes, hypertension is often present before the diabetes is diagnosed and antihypertensive therapy, especially thiazide diuretics, could play a demasking or favorizing role. The optimal blood pressure level to which these patients at high renal and coronary risk should be lowered still has to be determined. A prospective study, comparing the effects of strict (treated diastolic blood pressure less than 80 mmHg) and less strict (treated diastolic blood pressure between 90 and 100 mmHg) hypertensive control on coronary event prevention in essential hypertension, is in progress and will have important implications for hypertension treatment in diabetics. Appropriate treatment of other risk factors, such as hyperlipidaemia and smoking, contributes to coronary and renal prevention in all diabetic hypertensives.

Albuminuria↗
PubMed1990

Localization of the NGFI-A protein in the rat brain.

Antibodies are used to localize the NGFI-A protein in the rat brain. The protein is found in a wide variety of neurons. However, not all neurons are stained. The protein is either absent or present at undetectable levels in glial cells. Neuronal nuclei stain intensely, cytoplasmic staining is lighter. Seizures cause a detectable increase in the intensity of staining.

Amino Acid Sequence↗
PubMed1990

Auxiliary springs in continuous arch treatment: Part 2. Appliance use and case reports.

In the second part of this series, three clinical examples are presented to illustrate the use of auxiliary space-closure springs with clinically manageable moment-to-force ratios and new canine brackets to accommodate these springs within the framework of conventional and straight-wire 0.018-inch appliance systems. Eligiloy retraction spring models (0.1650 inch x 0.02150 inch) in the edgewise mode were developed for translational movements along a main archwire. The effects of different preactivation bends for influencing intraarch anchorage are shown for the conditions of reciprocal closure, posterior protraction, and anterior retraction.

Adolescent↗
PubMed1990

Auxiliary springs in continuous arch treatment: Part 1. An analytical study employing the finite-element method.

This report describes the results of a finite-element analysis with ANSYS (Version 4.3) from Swanson Analysis Systems and 1 mm-long, 2-D elastic beam elements to modify and refine the designs of maxillary and mandibular springs for space-closure management. This system permitted static analysis by means of modern software systems instead of expensive and cumbersome mechanical bench studies. Our examination of anterior and posterior reactions led to what we believe are optimal designs with clinically manageable moment/force ratios and new canine brackets that accommodate these springs within the framework of conventional and straight-wire appliance systems. Three degrees of freedom were used at each node for translations in the x and y directions and a rotation about the z axis, producing 182 elements with 183 nodes for the mandibular model and 146 elements with 147 nodes for the maxillary model. Elgiloy retraction spring models (0.1650 inch x 0.02150 inch) in the edgewise mode were developed so that the effects of three different preactivation bends could be refined by computer analysis. Sixty-four analyses were performed for each spring, with each of three angle bends (theta 1, theta 2, and theta 3) varied from 0 degrees to 45 degrees in 15 degrees increments. The employment of this computer method promises to simplify the design and development of complex interacting orthodontic systems. Clinical cases are presented in Part 2 of this series, which illustrates the application of auxiliary springs.

Computers↗
PubMed1989

Further results from a census based mortality study of fertiliser manufacturers.

The results of a further follow up of two cohorts of men identified as manufacturers of fertilisers in the 1961 and 1971 censuses of England and Wales are reported. Both cohorts have now been followed up until 1985 through the National Health Service Central Register. In the 1961 cohort the previous findings are replicated--low mortality from all causes, all cancers, and all circulatory diseases, and no evidence of dose response relation nor excess mortality from cancer at any site. In the 1971 cohort there remain more deaths from cancer than expected but none of the observed deaths from individual cancers differs significantly from expectation by comparison with national mortality rates or rates for other employed men. Evidence of an association between cancer mortality and frequency of exposure to nitrate containing dust is strengthened in the reanalysis of the 1971 cohort after longer follow up, but a negative trend, significant for digestive organ cancers, is observed in the analysis by product type in which manufacturers of straight nitrogen and compound fertilisers might have been expected to be most at risk. Failure to find specifically any excess mortality from gastric cancer and the contradictory dose response relations, weigh against the notion that the nonsignificant excesses of cancers in the 1971 cohort are related to nitrate exposure.

Air Pollutants, Occupational↗
PubMed1988

Pharmacokinetics of xamoterol after intravenous and oral administration to patients with chronic heart failure.

The pharmacokinetics of xamoterol, a beta-adrenergic partial agonist under clinical evaluation for the treatment of mild to moderate heart failure, have been studied in 8 cardiac failure patients (NYHA Class II) of mean age 62 years. After i.v. dosing, the elimination half-life was 7.4 +/- 0.4 h, the total body clearance was 228 +/- 30 ml.min-1 and the volume of distribution at steady-state was 56 +/- 9 l. 72.5 +/- 4.3% of the dose was recovered unchanged in urine. After the oral dose, the absolute bioavailability of xamoterol was shown to be 5.9%. Peak plasma concentrations occurred 1 to 2.5 h after the oral dose. The apparent elimination half-life was significantly longer after oral doses (16 +/- 2 h) compared to that observed after an intravenous dose. Renal clearance of xamoterol exceeded glomerular filtration rate as measured by creatinine clearance. The pharmacokinetics of xamoterol in cardiac failure patients with good renal function (creatinine clearance greater than 90 ml.min-1) were similar to published data in young healthy male volunteers.

Administration, Oral↗
PubMed1986

Ethidium cooperativity in the formation of complexes with CpG.

The formation of complexes between the self-complementary ribo-dinucleoside monophosphate CpG and ethidium ion is observed by use of an ethidium ion selective electrode. The ratio of total CpG to total ethidium was varied from 50:1 to .4:1, with CpG concentrations ranging from 0.2 to 1.1 mM. Scatchard plots show that the system is strongly cooperative with respect to ethidium ion; cooperativity with respect to dinucleoside has been previously reported (Krugh, T.R., Wittlin, F.N., and Cramer, S.P. (1975) Biopolymers 14,197-210). Cooperative behavior with respect to ethidium ion implies the existence of complexes containing at least two molecules of ethidium ion in combination with one or more CpG molecules.

Cytidine Monophosphate↗
PubMed1986

Computer-aided modeling in the assessment of the biomechanical determinants of diverse skeletal patterns.

Aberrant functional patterns of the masticatory musculature have been alleged as a factor influencing the morphogenesis of mandibular dysplasias. These include such expressions as the hyperdivergent skeletal open bite and its counterpart, the hypodivergent skeletal deep bite. A lack of anatomic data dealing with the actual musculoskeletal orientations of these types has resulted in speculative reports on divergent anatomy and its purported effects. In this study anatomic dissections of a hyperdivergent and a hypodivergent human cadaver illustrated that skeletally dysmorphic types possess different spatial orientations of the masticatory adductors in relation to dentofacial structures. A two-dimensional analysis of static equilibrium using computer-aided modeling demonstrated that these two types produce biomechanically distinct modes of muscle action. Temporalis activity must be 40% higher in the hyperdivergent model as compared with its counterpart to produce a biting force of 500 N (112 lb). The data suggest a rationale for the weak biting forces previously reported in long-faced persons when compared with horizontally developed subjects. The direction of condylar reaction force was also found to vary from a vertical orientation in the hyperdivergent model to oblique in the hypodivergent model. "Physis-like" behavior of the condyle, which can orient axially toward loading forces, may present an explanation for the reported differences in the direction of condylar growth in dysmorphic persons. A finite element analysis pictured distinct regions of deformation and compression in a novel perspective to help evaluate the currency of accepted hypotheses of stress-induced osteogenesis. The data support previous work reporting a latent geometric interdependency existing between muscle orientation and mandibular morphology.

Adult↗
PubMed1984

Comparative effects of long-acting and conventional propranolol on stress-induced angina pectoris and on frequency of ventricular premature beats.

Ten male patients with chronic stable angina pectoris completed a randomized, double-blind cross-over study, with matched placebo run-in period (P), to compare the effects of a long-acting preparation of propranolol (LA, 160 mg once a day) with that of conventional propranolol (CP, 40 mg four times a day) each given for 14 days. Response was assessed by symptom-limited bicycle ergometry, degree of ST segment depression, daily anginal attack rate and glyceryl trinitrin consumption (GTN). Heart rate and ventricular extra-systolic frequency (VES) were recorded by 24 h Holter monitor. Bicycle ergometry was performed and a trough blood sample taken for propranolol estimation on day 14 prior to the morning dose. Both formulations increased total work capacity (P 3412, LA 4095, CP 3697 kpm/min), reduced rate-pressure product (P 21896, LA 16011, CP 15609 mm Hg beats/min), and degree of ST segment depression (P 4.53, LA 2.48, CP 2.43), but without differences between the formulations. Daily anginal attack rate was reduced from 30 (placebo) to 7.5 (CP) and 14.5 (LA) (P less than 0.05 between treatment groups). There was a reduction in daily GTN consumption by both treatments. The heart rate and total number of VESs during 24 h was similar in the two treatment groups and was reduced in comparison with placebo. Both formulations were well tolerated. Long-acting propranolol is an effective and well-tolerated alternative to conventional propranolol in the treatment of chronic stable and stress-induced angina, and in reducing VES frequency.

Adult↗