Search PubMed⌕ Search

Biomedical subjects

S Powell

Publications and source records attributed to S Powell.

At least 109 records · Page 6Linked to original sources
PubMed1986

Effect of internal carotid artery occlusion on middle cerebral artery blood flow at rest and in response to hypercapnia.

In patients with symptomatic cerebrovascular disease the rise in middle cerebral artery (MCA) blood-flow velocity in response to hypercapnia, recorded with a pulsed transcranial doppler velocimeter, was significantly less in MCAs above a totally occluded carotid artery than in MCAs above a patent carotid. These findings support the existence of compensatory cerebral vasodilatation above a carotid occlusion and suggest that transient ischaemic attacks in patients with carotid occlusion may be flow-related rather than embolic phenomena. These patients may therefore benefit from extracranial-intracranial surgical revascularisation. The method presented is non-invasive and therefore ideally suited for use as a screening test or in follow-up studies.

Adult↗
PubMed1986

Augmented medial rectus recession in the management of esotropia.

Forty-six children awaiting surgery for concomitant esotropia were placed into two matched groups. One group received bilateral medial rectus recessions, while the second group received augmented bilateral medial rectus recessions. By recession the conjunctiva and subconjunctival tissue in addition to the medial rectus we consistently increased the correction obtained. With bilateral medial rectus recession to correct large angle esotropia application of the augmented technique is more likely to provide a full correction.

Child, Preschool↗
PubMed1985

Implications of DRG payments for medical intensive care.

Patients in the most prevalent DRGs in a Medical Intensive Care Unit (MICU) were compared with their counterparts who received only routine hospital care on adjusted total hospital costs and length of stay. Costs for both groups were compared with estimated DRG payments under an all-payer system. For patients in three DRGs, measures of severity of illness were examined as predictors of costs. Significant differences between MICU and routine care patients were found in 10 of 13 DRGs studied; intensive care costs were substantially above overall payment rates. The severity of illness measures varied widely in their correlation with costs, depending on DRG and whether the patients were MICU or routine care. These apparent differences in accounting costs may result in hospital decisions to restrict the number of MICU beds. Severity of illness adjustments to DRGs might produce more equitable payments. The most useful measure of severity may differ, however, depending on DRG.

Aged↗
PubMed1985

Is Nd-Yag laser treatment for upper gastrointestinal bleeds of benefit in a district general hospital?

104 consecutive patients with upper gastrointestinal bleeding admitted to a district general hospital over a period of 20 months were considered for laser photocoagulation. 58 patients were found to have peptic ulcers, of which 42 had stigmata of recent haemorrhage accessible to laser photocoagulation. 17 were treated with a Nd-YAG laser and 25 were managed conservatively. There was no significant difference in the number of patients who re-bled and required surgery, mortality rate, length of stay in hospital or the amount of blood transfusion required in either group. We suggest that the routine use of a laser for bleeding peptic ulcers in a district general hospital is not justified.

Aged↗
PubMed1983

Analysis of a new technique to stabilize the chronic peritoneal dialysis catheter.

A significant cause of morbidity for peritoneal dialysis patients is catheter dysfunction. In our experience, the most common cause of catheter dysfunction was cephalad migration of the catheter tip out of the true pelvis. A new technique for catheter placement that reduces catheter migration from 35% to 6% (P less than .01 chi 2) is described. Our results demonstrate that peritoneal catheters which dysfunction because of catheter flip generally do so in the first 3 months.

Catheterization↗
PubMed1983

Occult germ-cell testicular tumours.

Eighteen men presenting with metastatic germ-cell malignancy in whom no primary tumour could be palpated in either testis are described. All patients had both testes in the scrotal sac and none had a history of maldescent. All had abdominal node involvement, in most cases associated with metastases at other sites. Ten men presented with Stage 4 disease, five with Stage 3 and three with Stage 2. The most common histological sub-type associated with an occult primary testicular tumour was trophoblastic malignant teratoma (9/18 patients). Abdominal pain (12 patients) and systemic symptoms (10 patients) were common presenting features. There was a history of testicular atrophy in eight patients and seven had experienced episodes of transient testicular pain up to 18 months before presentation. In three of four patients in whom the testis was examined histologically following a history of atrophy and/or pain, there was evidence of a primary tumour, manifest as spontaneous tumour regression (one), differentiation (one) or a small micro-primary trophoblastic teratoma (one). In a fifth patient an ultrasonic scan showed a 1-cm echogenic mass in an atrophic testis. In 10 patients the diagnosis of germ-cell malignancy was established by laparotomy. Obstructive uropathy was present in six patients, associated with haematuria in four patients.

Humans↗
PubMed1983

Sarcoid-like lymphadenopathy in malignant teratoma.

The reported association between sarcoidosis and malignancy has relevance both to the diagnosis of the cause of lymphadenopathy and possibly also to the prognosis of the malignant disease. A case is reported in which mediastinal lymphadenopathy due to non-caseating epithelioid granulomata caused diagnostic difficulty in the staging investigation of a patient with malignant testicular teratoma.

Adult↗
PubMed1983

A framework for viewing the process of standard setting.

The standard-setting literature is filled with contributions in which issues associated with standards are discussed and various methods for setting standards are presented and reviewed. Almost no attention has been given to guidelines for helping standard-setting groups or committees address the issues and technical matters that arise in selecting and implementing a standard-setting method and finally setting a standard (or standards). This article was prepared to describe sets of context-setting variables and technical matters associated with standard-setting to assist groups or committees desiring to set standards in a systematic way.

Certification↗
PubMed1980

Plasma steroid concentrations in maternal and umbilical circulation after spontaneous onset of labor.

Blood samples were obtained from the maternal peripheral vein (n = 17) during the second stage of spontaneous labor and from the umbilical artery (UA) and vein (UVn) immediately after delivery. Four delta 4-and five delta 5-steroids as well as estradiol were measured by RIA. Additionally, cortisol was determined in maternal plasma. The maternal concentrations were compared with our control values obtained from samples (n = 30) collected at term but not in labor. All delta 5-steroids and F were significantly higher during labor than before labor. In the umbilical circulation, progesterone and 17-hydroxyprogesterone were significantly higher in the UVn than in UA (P < 0.05). Whereas androstenedione was significantly higher in the UA [1.01 +/- 0.12 ng/ml (mean +/- SEM)] than in the UVn (0.72 +/- 0.07 ng/ml), testosterone was almost identical in the two (UA, 0.33 +/- 0.03 ng/ml; UVn, 0.35 +/- 0.08 ng/ml). Four of the five delta 5-steroids (dehydroepiandrosterone, dehydroepiandrosterone sulfate, pregnenolone sulfate, and 17-hydroxypregnenolone) had significantly higher concentrations in the UA than in the UVn (P < 0.05). However, pregnenolone levels were not significantly different (UVn, 21.8 +/- 2.0 ng/ml; UA, 18.0 +/- 2.0 ng/ml). No significant correlations were observed between maternal and umbilical steroid concentrations.

17-alpha-Hydroxypregnenolone↗
PubMed1980

Aminoglycoside nephrotoxicity in dogs: dependence on drug, dose and regimen.

In female mongrel dogs nephrotoxicity of three aminoglycosides (gentamicin, tobramycin and netilmicin) was compared with relation to the cortical aminoglycoside concentration. A standard regimen of 45 mg/kg/day with constant intravenous infusion and once daily dosing of each aminoglycoside was used, and in subsequent dogs netilmicin daily dose was increased to an average of 73 mg/kg/day.

Animals↗