Biomedical subjects

A J Jenkins

Publications and source records attributed to A J Jenkins.

6 recordsLinked to original sources

PubMed1992

Plasma apolipoprotein (a) is increased in type 2 (non-insulin-dependent) diabetic patients with microalbuminuria.

Patients with Type 2 (non-insulin-dependent) diabetes mellitus complicated by microalbuminuria or albuminuria, have an increased risk of developing macrovascular disease and of early mortality. Because lipoprotein abnormalities have been associated with diabetic nephropathy, this study tested the hypothesis that levels of apolipoprotein (a) are elevated in patients with Type 2 diabetes and increased levels of urinary albumin loss. Levels of apolipoprotein (a) in diabetic patients with microalbuminuria (n = 26, geometric mean 195 U/l, 95% confidence interval 117-324) and albuminuria (n = 19, 281 U/l, 165-479) were higher than in non-diabetic control subjects (n = 140, 107 U/l, 85-134, p < 0.05), and in the albuminuric group than diabetic patients without urinary albumin loss (n = 58, 114 U/l, 76-169, p < 0.05). Patients with microalbuminuria and albuminuria had levels comparable with patients undergoing elective coronary artery graft surgery (n = 40, 193 U/l, 126-298). Apolipoprotein (a) levels were higher in diabetic patients with macrovascular disease than in those without (n = 49, 209 U/l, 143-306 vs n = 54, 116 U/l, 78-173, p < 0.05). These preliminary results suggest that raised apolipoprotein (a) levels of Type 2 diabetic patients with microalbuminuria and albuminuria may contribute to their propensity to macrovascular disease and early mortality.

Aged↗

PubMed1991

Increased plasma apolipoprotein(a) levels in IDDM patients with microalbuminuria.

Patients with insulin-dependent diabetes mellitus (IDDM) have a significantly increased risk of macrovascular disease, particularly if they have persistent proteinuria. To determine whether altered levels of apolipoprotein(a) [apo(a)], the plasminogenlike glycoprotein of the potentially atherogenic lipoprotein(a); contribute to the increased risk of atherosclerosis, apo(a) levels were measured in 107 patients with IDDM and compared with nondiabetic control subjects and male elective coronary artery graft patients. Apo(a) levels were increased in diabetic patients with microalbuminuria (geometric mean 245 U/L, 95% confidence interval [CI] 142-427, n = 30) and albuminuria (mean 196 U/L, 95% CI 97-397, n = 18) with levels comparable to patients with coronary artery disease (mean 193 U/L, 95% CI 126-298, n = 40), which were higher than in the control group (mean 107 U/L, 95% CI 85-134, n = 140; P = 0.016). Apo(a) levels in diabetic patients without microalbuminuria (mean 86 U/L, 95% CI 63-116, n = 59) were comparable with the control population and less than in those with microalbuminuria (P less than 0.001) and albuminuria (P = 0.014). The elevated apo(a) levels found in patients with IDDM and increased urinary albumin loss may contribute to their heightened risk of macrovascular disease.

Adult↗

PubMed1989

Arcuate area of the female rat maintained in vitro exhibits increased afternoon electrical activity.

The arcuate area of the rat hypothalamus has previously been shown to have increased neuronal activity in vivo corresponding to the estradiol-induced luteinizing hormone rise in the afternoon. The present experiments investigate the arcuate area to determine whether afternoon increases in activity occur in vitro and are dependent on estradiol pretreatment. Light-dark entrained pubertal rats were ovariectomized and implanted with estradiol- or cholesterol-filled silastic capsules. Two days later they were sacrificed at 10.00 h and coronal sections containing the arcuate area were maintained in oxygenated artificial cerebrospinal fluid at 34 degrees C. With estrogen pretreatment, units recorded from 11.00 to 15.00 h had a slow discharge with hourly mean rates ranging from 0.7 to 0.86 spikes/s. However, in the next hour the mean firing rate doubled (p less than 0.01) and an increase in units encountered per electrode penetration was observed. In tissue from animals sacrificed 3 h later, an increase in firing rate was also noted after 15.00 h, suggesting that a diurnal mechanism rather than a technical artifact was responsible for the timing of the activity increase. In control experiments with cholesterol capsules, electrical activity did not have a diurnal pattern. In summary, the arcuate area of the rat isolated in vitro was observed to display an increase in neuronal activity during the afternoon that was dependent on estrogen pretreatment and correlated to the time of day that luteinizing hormone rises are seen in intact animals. Although the arcuate area is involved in numerous functions, this electrical activity may represent interneurons controlling the release of luteinizing hormone-releasing hormone from axonal endings in the median eminence.

Animals↗

PubMed1988

Pressure support ventilation.

The management of patients with respiratory failure can be challenging. A relatively new technique may be useful in freeing these patients from mechanical ventilation. With a spontaneously taken breath, positive pressure is provided by a ventilator equipped to detect small changes in airway pressure. Pressure support ventilation may mean the difference between an independent life and ventilator dependency.

Humans↗

PubMed1986

A DNA fragment containing the groE genes can suppress mutations in the Escherichia coli dnaA gene.

An 8.2 kb fragment of E. coli chromosomal DNA, when cloned in increased copy number, suppresses the dnaA46 mutation, and an abundant protein of about 68 kd (60 kd when measured by us), encoded by the fragment, is essential for the suppression (Takeda and Hirota 1982). Mapping experiments show that the fragment originates from the 94 min region of the chromosome. It encodes several proteins but only one abundant polypeptide of the correct size, the product of the groEL gene. Suppression by the fragment is allele specific; those mutations which map to the centre of the gene are suppressed. Other initiation mutants including dnaA203, dnaA204, dnaA508, dnaAam, dnaC, dnaP and dnaB252 are not suppressed. Most suppressed strains are cold-sensitive suggesting an interaction between the mutant proteins (or their genes) and the suppressing protein or proteins.

Bacterial Proteins↗

PubMedDate not supplied

Laser-Doppler velocimetry and photoplethysmography in the diagnosis of abnormal venous reflux.

Laser-Doppler Velocimetry (LDV) is useful in measurement of relative tissue blood flow. We have found a change in both the variability of the LDV waveform and its absolute level when measured in the supine and dependent limb, in patients with venous reflux. These changes correlated with simultaneous photo-plethysmographic (PPG) assessment of venous reflux and were more pronounced in patients with leg ulcers. These changes were also reduced by compression bandaging.

Humans↗