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Biomedical subjects

G Murray

Publications and source records attributed to G Murray.

At least 127 records · Page 7Linked to original sources
PubMed1985

Neodymium: YAG lasers. An FDA report.

Analysis of data from four neodymium:YAG laser manufacturers submitted to the Food and Drug Administration (FDA) on over 17,000 cases indicate the procedure is safe and effective for cutting opaque posterior lens capsules. A successful opening in the pupillary membrane was achieved in 98% of the cases, and vision improved in 84% of the cases. Clinically significant risks include: a rise in intraocular pressure two to four hours after treatment, damage to the intraocular lens, and rupture of the anterior hyaloid face.

Humans↗
PubMed1985

Cardiovascular responses to verapamil and propranolol in hypertensive patients.

Since there is concern that the potentially useful antihypertensive combination of verapamil and propranolol might lead to adverse cardiovascular responses, we have investigated its effects, not only on blood pressure, but also on electrocardiographic and echocardiographic variables. Fourteen hypertensive patients participated in a double-blind, randomized, crossover comparison of verapamil 360 mg, propranolol 240 mg, verapamil 360 mg + propranolol 240 mg, and placebo, each given for 4 weeks. The antihypertensive effect of verapamil + propranolol was greater than that of either drug alone. Pulse rate was reduced by propranolol but not verapamil. However, addition of verapamil to propranolol led to further reduction in pulse rate. The PR interval was prolonged by verapamil + propranolol when compared with all other treatments. The active drugs increased ventricular dimensions and the effect of the combination was statistically significant. Thus, verapamil + propranolol is an effective antihypertensive combination, but heart rate, atrio-ventricular conduction and left ventricular function may be affected adversely, necessitating careful monitoring of therapy.

Adult↗
PubMed1985

Factors influencing mortality in malignant hypertension.

In a study designed primarily to assess mortality, 139 consecutive patients presenting with malignant hypertension (MHT) in Glasgow between 1968 and 1983 were matched individually for age, sex and initial blood pressure with 139 non-malignant hypertensives attending the Glasgow Blood Pressure Clinic. Fifty-four patients with MHT and 34 controls died before 1 April 1984. Multivariate analysis showed that initial serum creatinine and blood pressure achieved during treatment were significantly and independently related to outcome among the patients with MHT, but that age, smoking habit, presence of papilloedema, underlying diagnosis, initial blood pressure and year of presentation were not. Overall survival among patients with MHT was 63% at 5 years and 47% at 10 years. Although this was better than in earlier studies patients with MHT were still twice as likely to die as non-malignant controls. The excess mortality was confined largely to patients with underlying renal disease and/or renal failure at presentation. Moreover, renal failure contributed to four times more deaths among patients with MHT than controls. Thus, despite an improvement in survival compared with previous years, renal failure remains the most serious manifestation of patients with this disease.

Female↗
PubMed1984

Use of a conductivity meter for the detection of subclinical mastitis.

The conductivity of milk from 164 cows in four herds was measured. There were significant differences between the normal and the mastitic quarters in each of the four herds. However, there was a marked difference in conductivity levels between the herds, the mean conductivity of the normal quarters in one herd being higher than that of the mastitic quarters in another herd. In a trial using a hand-held mastitis detector on 123 cows from three herds, 91 per cent of the 106 mastitic quarters were detected. However, 33 per cent of the 315 normal quarters also gave a positive reading.

Animals↗
PubMed1984

Pressor effects of brief and prolonged infusions of epinephrine in the conscious rat.

Plasma epinephrine may be increased in some patients with essential hypertension, and prolonged infusion of this catecholamine has been claimed to raise blood pressure. The objectives of our experiments were to determine whether continuous intravenous infusion of epinephrine raised blood pressure in a rat preparation known to respond in this way to angiotensin II in low dose and, if so, the plasma concentration of epinephrine required to raise pressure in comparison to the physiological range of plasma catecholamine concentration in the rat. Intravenous infusion of epinephrine at a rate of 400 ng X kg-1. min-1 or less for 30 min into Wistar rats did not increase mean arterial pressure (MAP); pressure did rise when the rate was increased to 800 ng X kg-1. min-1. However, when rats were given epinephrine at 400 ng X kg-1. min-1 for 4 days with continuous blood pressure recording, average MAP showed a progressive rise on successive days of infusion, reaching a maximum increase of 12 mmHg on the 4th and final day of infusion (P less than 0.02). Blood pressure did not change significantly during epinephrine infusion at 10 and 70 ng X kg-1. min-1. Plasma epinephrine was raised more than 13 times basal at the highest rate of infusion. In comparison, blood pressure and catecholamine concentrations increased only slightly although significantly during a period of restraint. We confirm the existence of a slowly developing pressor effect of epinephrine, but it is small and requires a large sustained increase of plasma epinephrine for its development.

Animals↗
PubMed1984

Bioelectric properties and ion flow across excised human bronchi.

Bioelectric properties and ion transport of excised human segmental/subsegmental bronchi were measured in specimens from 40 patients. Transepithelial electric potential difference (PD), short-circuit current (Isc), and conductance (G), averaged 5.8 mV (lumen negative), 51 microA X cm-2, and 9 mS X cm-2, respectively. Na+ was absorbed from lumen to interstitium under open- and short-circuit conditions. Cl- flows were symmetrical under short-circuit conditions. Isc was abolished by 10(-4) M ouabain. Amiloride inhibited Isc (the concentration necessary to achieve 50% of the maximal effect = 7 X 10(-7) M) and abolished net Na+ transport. PD and Isc were not reduced to zero by amiloride because a net Cl- secretion was induced that reflected a reduction in Cl- flow in the absorptive direction (Jm----sCl-). Acetylcholine (10(-4) M) induced an electrically silent, matched flow of Na+ (1.7 mueq X cm-1 X h-1) and Cl- (1.9 mueq X cm-12 X h-1) toward the lumen. This response was blocked by atropine. Phenylephrine (10(-5) M) did not affect bioelectric properties or unidirectional ion flows, whereas isoproterenol (10(-5) M) induced a small increase in Isc (10%) without changing net ion flows significantly. We conclude that 1) Na+ absorption is the major active ion transport across excised human bronchi, 2) Na+ absorption is both amiloride and ouabain sensitive, 3) Cl- secretion can be induced by inhibition of the entry of luminal Na+ into the epithelia, and 4) cholinergic more than adrenergic agents modulate basal ion flow, probably by affecting gland output.

Acetylcholine↗
PubMed1984

A comparison of the effect of flurbiprofen, dexamethasone, and placebo on cyclocryotherapy-induced inflammation.

A double-blind study was performed to compare the effects of a placebo, a topical corticosteroid, and a topical non-steroidal prostaglandin inhibitor on the inflammation and the course of intraocular pressure that follows cyclocryotherapy. Flurbiprofen 0.03%, dexamethasone phosphate 0.1%, and a sterile vehicle placebo were used both pre and postoperatively. Less anterior chamber flare was seen in flurbiprofen-treated eyes than those receiving placebo, but only at four weeks after surgery. More erythema was seen in flurbiprofen-treated eyes than in those receiving dexamethasone. Significance was approached showing more anterior chamber cells in placebo-treated eyes than in steroid-treated eyes. Cyclocryotherapy produces inflammation which is difficult to control with topically administered medications.

Adult↗
PubMed1984

The use of methylphenidate in depressed patients after cardiac surgery.

A positive therapeutic response to methylphenidate is described in four depressed patients who developed cardiovascular complications after cardiac surgery that contraindicated the use of tricyclic antidepressants. There was a rapid remission of depressive symptomatology with no adverse side effects. This observation is consistent with the findings of other investigators. Further evaluation of the therapeutic role of psychostimulants in the treatment of medically ill depressed patients is recommended.

Aged↗
PubMed1983

Risks of intracranial haematoma in head injured adults.

A study was conducted to estimate the risk that an adult (age 15 or over) will develop a surgically significant intracranial haematoma after a head injury. Two simple features were used that can be recognised by clinicians with minimal training: a skull fracture and the conscious level. The risks were calculated from samples of 545 patients with haematomas, 2773 head injured patients in accident and emergency departments, and 2783 head injured patients in primary surgical wards. With radiological evidence of skull fracture and any impairment of consciousness (including disorientation) one patient in four in an accident and emergency department or primary surgical ward will develop a haematoma. With no skull fracture and preserved orientation the risk to a patient in an accident and emergency department is one in 6000. The use of risk levels as a basis for decision making about head injured patients may result in fewer haematomas being detected too late and savings of resources by reducing the admission and investigation of low risk categories of patients.

Adolescent↗
PubMed1983

Haemodynamic effects of a new vasodilator drug, felodipine, in healthy subjects.

The haemodynamic effects of a new vasodilating drug, felodipine, were studied in eight, healthy, male subjects, aged 22-31 years. The drug was given as an oral solution in the dose of 0.15 mg/kg. Thirty-five minutes later further dose of 0.15 mg/kg was administered. Felodipine induced a pronounced decrease in diastolic blood pressure (maximal effect 15 +/- 4 mm Hg) and in the systemic vascular resistance. Cardiac output increased (maximum by 4.2 +/- 0.31/min), due to an increase both in the stroke volume and the heart rate. The maximal increase in the stroke volume (measured from echo cardiograms) and the heart rate were 33 +/- 5 ml and 23 +/- 3 beats/min, respectively. Felodipine caused a significant decrease in the pre-ejection period (23 +/- 3 ms) and an increase in the left ventricular ejection time (29 +/- 3 ms). The quotient PEP/LVET fell from 0.36 +/- 0.01 to 0.28 +/- 0.01. Significant activity of felodipine could be recorded at a plasma level of about 15 nmol/l. When the maximal haemodynamic effects were recorded the plasma level was about 40 nmol/l. After a cumulative dose of 0.30 mg/kg, there was a twofold variation in the maximal plasma level (from 31 to 61 nmol/l). The results of the present investigation are in agreement with previous haemodynamic studies in animals. It would appear that felodipine is a potent arteriolar vasodilator and it might well be of considerable value in the management of patients with hypertension or congestive cardiac failure.

Adult↗
PubMed1980

Craniometric measurements of craniofacial malformations in mice with X-linked, dominant hypophosphatemia (vitamin D-resistant rickets).

Skulls of hemizygous male and heterozygous female C57CL/6J mice affected with X-linked, dominant hypophosphatemia ("Hyp" mutant; C57BL/6J-Hyp)--vitamin D-resistant rickets (VDRR)--were compared grossly and by craniometry with skulls of normal C57BL/6J mice to describe the malformation that accompanies this condition. In mutant males a slight retardation in mandibular growth is observed. The neurocranium of mutants is shorter, more domed, and exhibits frontal and occipital bossing. Retardation in growth of the viscerocranium occurs. A characteristic protrusion of the frontopremaxillary suture is present at the junction of the neural and facial skulls. No differences in width are demonstrable. The malformation in mutant females is similar to that found in males but is less pronounced. The craniofacial malformations in humans with VDRR are generally similar to those described in the C57BL/6J-Hyp mouse.

Animals↗