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Biomedical subjects

M Day

Publications and source records attributed to M Day.

At least 55 records · Page 3Linked to original sources

Plasmid replication and maintenance in binary fissile microorganisms.

The mechanisms of nonconjugative plasmid replication (in the single cell) and maintenance (at the population level) are of concern to the microbiologist and to the genetic engineer who wishes to exploit their ability to express cloned genes. This article concentrates mainly on Escherichia coli as the host organism and examines the mechanisms by which both naturally occurring and genetically engineered plasmids persist in populations during periods of growth. Additional strategies to ensure high yields of recombinant product are briefly considered.

Cell Division↗

Self blood pressure measurement at home.

Forty-six untreated patients measured their blood pressure at home for three weeks using an A and D, UA 751 automatic device, and were examined three times at the outpatient clinic. Home blood pressure was significantly lower than clinic blood pressure, even at the third visit when the correlations between clinic and home values were the most significant. The differences between clinic and home values had a gaussian distribution. The variance analysis of home blood pressure values showed that 67% of the variance was attributable to the between-subject component, 2% to the day effect, 15% to the time of the day effect and 16% to the residual (the measurement error). The standard deviation of the difference between two five-day periods of self blood pressure monitoring at home (5.4 and 4.1 mm Hg) was much lower than what has been reported for clinic measurements or 24-hour ambulatory monitoring.

Adult↗

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↗

[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↗

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↗

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↗

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↗

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↗

Going back to basics.

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Centralized Hospital Services↗

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↗

Luteinizing hormone and progesterone concentrations in serum of heifers administered a short half-life prostaglandin (PGF(2alpha)) or long half-life prostaglandin analogue (fenprostalene) on days six or eleven of the estrous cycle.

Two trials were conducted to measure the progesterone (P(4)) decline and luteinizing hormone (LH) surge in serum subsequent to administration of a short half-life (short t (1 2 )) prostaglandin (PGF(2alpha)) or a long half-life (long t (1 2 )) prostaglandin analogue (fenprostalene) on Days 6 or 11 of the estrous cycle. Twenty-five crossbred Shorthorn and five Hereford heifers with a mean weight of 331.4 +/- 29.8 kg were used in both trials. The heifers were randomly allotted to receive either a short t (1 2 ) or long t (1 2 ) prostaglandin treatment on Day 6 or 11 of the estrous cycle. A crossover design for the main effect, treatment (type of prostaglandin), was conducted. Heifers that received PGF(2alpha) in Trial I were given fenprostalene in Trial II and vice versa. Stage of the estrous cycle (day) was the same for each heifer in both trials. Stage of estrous cycle was standardized to either Day 6 or 11 by administering Syncro-Mate B (SMB). Blood was collected every hour for 80 h post injection to quantify LH and P(4) concentrations. There were no significant differences (P > 0.05) between the short t (1 2 ) or long t (1 2 ) for either P(4) or LH profiles. In addition, no differences were detected between stages of the estrous cycle for the timing of the preovulatory surge of LH after prostaglandin administration.

Journal Article↗