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Biomedical subjects

R Hooper

Publications and source records attributed to R Hooper.

At least 19 recordsLinked to original sources
PubMed1992

Vestibulo-ocular compensation following unilateral vestibular deafferentation.

Vestibulo-ocular compensation following vestibular deafferentation was investigated in 26 acoustic neuroma patients following tumor removal and in 5 Menière's disease patients following vestibular nerve section by using sinusoidal harmonic acceleration testing. All three test parameters (phase lead, gain, and asymmetry), when averaged, shifted significantly on the first postoperative test (average 0.4 months after operation). A marked progression in central compensation with gain returning to the range of normal control values was seen in the tests performed 1 to 6 months (average 2.6 months) postoperatively. However, phase lead and asymmetry (especially at 0.01, 0.02, 0.04, and 0.08 Hz) remained outside the range of normal control values, and all three parameters failed to return to their preoperative level even when tested at more than 12 months (average 20.2 months) after operation. This finding indicates that the deficits of the vestibulo-ocular reflex to head acceleration are of long duration if not permanent.

Adaptation, Physiological↗
PubMed1990

Temporal bone meningiomas.

Meningiomas should be considered in the differential diagnosis of space-occupying lesions of the temporal bone. Five cases of meningiomas of the temporal bone are described and the literature reviewed. These tumours may stimulate Schwannomas and glomus tumours in their presentation and radiological findings. The tumours were managed by combining standard neurosurgical approaches with temporal bone and skull base techniques.

Adolescent↗
PubMed1985

Effect of probenecid on the disposition of captopril and captopril dimer in the rat.

The urinary excretion of captopril has been studied in a bladder-cannulated rat model and compared with that obtained after co-administration with probenecid. Probenecid reduced significantly the urinary excretion of captopril from 41% to 21% of the administered dose over a 3-hr period and significantly lowered urine flow rates. In addition, the effect of probenecid on plasma levels of captopril and total captopril (captopril plus disulfides) after oral administration of the disulfide prodrug captopril dimer (10 mg/kg) has been studied in a conscious rat preparation. Co-administration of probenecid (20 mg/kg) given either orally or intravenously increased both the plasma levels of captopril and total captopril (captopril plus captopril disulfides) over a 4-hr period. A prolonged significant inhibition of plasma ACE after co-administration of probenecid and captopril dimer suggests that probenecid may be useful to prolong the action of captopril or the prodrug captopril dimer.

Animals↗
PubMed1984

Esophageal transit scintigraphy--a cautionary note.

Esophageal transit scintigraphy and esophageal manometry were compared in forty-two patients with symptoms of esophageal disease. Fifteen healthy volunteers were studied as a control group for the scintigraphic investigation. Agreement between the tests was present in 79% of patients. In all the five patients in whom the esophageal manometry was abnormal and the esophageal transit study was normal, the manometric finding was "giant esophageal contractions." In four of the control group an abnormal transit pattern was observed on one of two esophageal studies. Esophageal transit scintigraphy has some limitations as a screening test for esophageal motor dysfunction.

Adolescent↗
PubMed1983

Portal and pulmonary hypertension with microangiopathic hemolytic anemia.

Marked pulmonary hypertension developed in a 40-year-old man with known cirrhosis and a previous portosystemic shunt. Terminally, he also showed signs of microangiopathic hemolytic anemia. At postmortem examination, he had severe plexiform dilatation lesions in the pulmonary vasculature, with deposition of fibrin in the vasculature channels. It is suggested that the site of microangiopathic red cell damage was the pulmonary microvasculature.

Adult↗
PubMed1983

An assessment of the physical properties of a multiplane tomographic imager.

The Pho/Con is a dual Anger camera multiplane tomographic scanner, capable of producing longitudinal tomograms through the subject. The physical characteristics of this device have been investigated. The resolution capabilities in three dimensions have been determined, and sensitivity, linearity, and uniformity of each detector have been studied with a view to establishing the influence of each of the subcomponents of the detector on overall performance. Experimental measurements have been made using both analogue and computerised reconstruction techniques.

Tomography, Emission-Computed↗
PubMed1982

Pharmacokinetic properties of captopril after acute and chronic administration to hypertensive subjects.

The pharmacokinetic properties of captopril were studied in two groups of hypertensive patients; (1) those who had never taken captopril (acute group), and (2) those who had been taking captopril for at least 6 months (chronic group). It was found that after 100 mg of captopril orally, the mean peak plasma level in the chronic group was three times higher than that in the acute group while the area under the curve was twice as high in the chronic group. These data suggest that bioavailability increases with chronic administration, and thus it may be possible to reduce the dosage of captopril and still maintain blood pressure control while reducing side effects.

Captopril↗
PubMed1976

Paravertebral lumbar myelomeningocele: a report of three cases.

Three cases of lateral myelomeningocele in the lumbar region are reported because of their rarity. It is stressed that in these laterally placed cystic swellings spinal dysplastic conditions should be also considered. The literature is briefly reviewed.

Female↗
PubMed1976

Pepsin secretion in the anaesthetized cat and the effect of sympathetic nerve stimulation.

1. Experiments were performed on chloralose anaesthetized cats and gastric mucosal blood flow, acid and pepsin secretions were measured. Gastric mucosal pepsin and protein contents were measured at the end of the experiments which were done in three groups: gastrin (A), vagal (B), vagal and sympathetic nerve (C) stimulations. 2. Vagal stimulation significantly reduced (76%) the pepsin content of gastric mucosa compared with gastrin stimulated animals, none of which secreted pepsin. 3. The sum of the secreted and extracted pepsins for all the three groups was not significantly different. There was no significant difference in the extracted protein from any of the groups. 4. Gastric mucosal blood flow, acid and pepsin outputs all had significant correlations with time during the first 70 min of vagal stimulation. During the period 80-160 min of vagal stimulation acid secretion and mucosal blood flow were not correlated with time but pepsin output declined significantly. From 170 to 220 min of vagal stimulation, acid and pepsin outputs and mucosal blood flow were not correlated with time. 5. The assumed pepsin store during each period was calculated and after 40 min of vagal stimulation there is a constant percentage pepsin output from this assumed store. 6. There is some data to suggest that pepsinogen synthesis was occurring during the period 170-220 min of vagal stimulation. 7. Sympathetic nerve stimulation which started at 160 min after the beginning of sustained vagal stimulation, significantly inhibited gastric acid secretion and mucosal blood flow, and in addition it significantly inhibited pepsin secretion. This is consistent with the hypothesis that sympathetic nerve inhibition of gastric mucosal function is mediated by a vasoconstrictor mechanism.

Animals↗
PubMed1975

Cysts of the parotid gland.

Simple cysts of the parotid gland are uncommon, and they have only rarely been reported. Two cases are reported here. The aetiology and management of parotid cysts is discussed.

Adult↗
PubMed1975

Intracranial tumours in childhood.

420 paediatric intracranial tumour cases were admitted from an area with a 2 million population in 20 years. The incidence of various groups in Melbourne is compared to similar series in Boston, Vienna, and Tokyo. The author believes that there is a remarkable uniformity in their distribution. The greater number of ependymomas in Melbourne can be due to different pathological interpretations. The higher rate of optic gliomas can be related to a higher frequency of neurofibromatosis. Myodil ventriculography followed by immediate surgery without disturbance of the child's position on the author's neurosurgical wheel reduces post-operative morbidity and mortality. The author uses the anterior approach to choroidal papillomas, contralateral approach to trigone tumours and occasionally posterior fossa osteoplastic flaps. Over the years, operative mortality has decreased to less than 5% but the overall survival rate has not greatly changed, which is possibly due to the excessive 'growth potential' of children.

Astrocytoma↗