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Biomedical subjects

P Creighton

Publications and source records attributed to P Creighton.

13 recordsLinked to original sources

Stopping drug treatment of hypertension: experience in 18 British general practices.

BACKGROUND: Of the many reports published describing the effect of withdrawing antihypertensive medication from patients who have well-controlled blood pressure, none have been major British general practice studies. Studies from other settings have shown that a substantial minority can do so without harm or resulting in the relapse of their hypertension. AIM: To determine the proportion of hypertensive patients who could have their medication withdrawn without relapse, and to seek factors associated with success at withdrawal. METHOD: A longitudinal observational study in 18 general practices in north-east England. Practices selected and managed patients to guidelines suggested by the study protocol. Data were abstracted from records by practice staff over three years of follow-up. RESULTS: A total of 196 out of 224 (88%) patients were followed up. Forty-three (22%) of these 196 remained normotensive off medication for the whole study. A total of 108 (55%) of the 196 had restarted medication by three months. Twenty-six (31%) of the 84 males, but only 17 (15%) of the 112 females, remained off medication. No differences in age, morbidity, symptoms, or biochemical parameters occurred between the group who stayed off medication and those who restarted it. Apart from male sex, no factors were found that enabled the prediction of patients more likely to succeed at stopping medication. CONCLUSIONS: One-fifth of well-controlled hypertensives in British primary health care could have their medication withdrawn without the relapse of their hypertension or any harm. Of those that do relapse, over half are likely to have done so before three months. Life-long observation of all patients is essential.

Adult↗

Retinopathy induced in mice by targeted disruption of the rhodopsin gene.

Retinitis pigmentosa (RP) represents the most common mendelian degenerative retinopathy of man, involving death of rod photoreceptors, cone cell degeneration, retinal vessel attenuation and pigmentary deposits. The patient experiences night blindness, usually followed by progressive loss of visual field. Genetic linkage between an autosomal dominant RP locus and rhodopsin, the photoreactive pigment of the rod cells, led to the identification of mutations within the rhodopsin gene in both dominant and recessive forms of RP. To better understand the functional and structural role of rhodopsin in the normal retina and in the pathogenesis of retinal disease, we generated mice carrying a targeted disruption of the rhodopsin gene. Rho-/- mice do not elaborate rod outer segments, losing their photoreceptors over 3 months. There is no rod ERG response in 8-week-old animals. Rho+/- animals retain the majority of their photoreceptors although the inner and outer segments of these cells display some structural disorganization, the outer segments becoming shorter in older mice. These animals should provide a useful genetic background on which to express other mutant opsin transgenes, as well as a model to assess the therapeutic potential of re-introducing functional rhodopsin genes into degenerating retinal tissues.

Age Factors↗

Blood pressure control of drug treated hypertension in 18 general practices.

This study examined the blood pressure (BP) control and number of drugs prescribed for a sample of hypertensive patients from 18 practices in Northeast England. Out of a total of 35,379 registered patients aged 40-69 years, 2995 (8.5%) were on treatment for hypertension. Data was abstracted from the practice records of a random sample of 691 patients. Using British Hypertension Society standards, BP control was optimal for systolic pressure (less than 160 mm Hg) in 469 (68%), and for diastolic pressure (less than 90 mm Hg) in 345 (50%), but only 269 (39%) had optimally controlled systolic and diastolic pressures. Sixty-one per cent were taking one drug and 39% two or more; 82% of patients aged 40-49 years but only 61% of those aged 60-69 years had optimally controlled systolic pressures. Forty-three per cent of the 40 to 49-year-old group and 56% of the 60 to 69-year-old group had optimally controlled diastolic pressures. A strong inverse relationship was found between age and systolic BP control but there was no association between age and diastolic pressure or the number of drugs being prescribed. Sub-optimal BP control is a major problem and remedial strategies should stress the greater gain from treating older patients.

Adult↗

Mapping of bovine markers CYP21, PRL, and BOLA DRBP1 by genetic linkage analysis in reference pedigrees.

We have analyzed DNA from 13 bovine reference pedigrees using primers specific for microsatellite markers derived from the 21-steroid hydroxylase (CYP21) and prolactin (PRL) genes and the leukocyte antigen (BOLA DRBP1) pseudogene. Linkage was demonstrated between PRL and BOLA DRBP1 (theta = 0.05; Z = 19.6), cyp21 and PRL (theta = 0.13; Z = 6.8), and BOLA DRBP1 and CYP21 (theta = 0.17; Z = 10.4). These results suggest an order BOLA DRBP1-PRL-CYP21, although in a multilocus analysis the alternative order PRL-BOLA DRBP1-CYP21 was also possible. The data confirm and extend the previously established syntenic relationship between these markers on bovine chromosome 23 and provide points of anchorage for further linkage studies in the reference pedigrees described.

Animals↗

Visualization of pig sperm chromosomes by in-vitro penetration of zona-free hamster ova.

Zona-free hamster eggs were penetrated by pig spermatozoa capacitated using bovine follicular fluid and Percoll gradients. A mean penetration rate of 80.1% was obtained from 5 ejaculates from 2 boars. Penetrated eggs were cultured and analysable metaphase chromosome spreads were obtained from 16.8%. The analysis of 20 pig sperm complements indicated that 9 were 19, Y, 10 were 19, X and 1 appeared to have an XY sex chromosome constitution.

Animals↗