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Biomedical subjects

J Hamer

Publications and source records attributed to J Hamer.

At least 73 records · Page 4Linked to original sources
PubMed1977

[Distal ulnar nerve compression at the wrist. "Loge de Guyon" and "deep ulnar branch" syndrome (author's transl)].

The distal non-traumatic ulnar nerve compression syndrome can be dividded into two types: -i) the proximal (paralytic) type caused by compression in the "Loge de Guyon", with involvement of both the superficial sensory and the deep branch, including the motor branch to the hypothenar muscles, and, ii) the distal, more common, purely motor type (the deep ulnar branch syndrome) with paresis of the interossei and the adductor pollicis, and less commonly of the hypothenar muscles. Whereas the proximal type has various causes, particularly pressure and occupational trauma, the distal type is almost exclusively the result of extra-neural ganglion cysts. An accurate diagnosis is made possible by electromyography and nerve conduction studies. The sensory nerve action potentials, distal motor latency to the hypothenar and adductor pollicis muscles, and the corresponding muscle action potentials after nerve stimulation are pathologically altered, according to the type of lesion. Although spontaneous recovery may occur, operation is the treatment of choice, provided that simple pressure palsy is eliminated.

Action Potentials↗
PubMed1977

Influence of systemic and cerebral vascular factors on the cerebrospinal fluid pulse waves.

In anesthetized, artificially ventilated dogs, the intracranial cerebrospinal fluid (CSF) pulse waves were studied simultaneously with the central aortic pressure, central venous pressure (CVP), and the sagital sinus pressure under physiological conditions and in normovolemic arterial hypotension and hypertension, in acute cardiac insufficiency of the right atrium, in raised intracranial pressure (ICP), and in arterial hypoxemia. The physiological CSF pulsations are shown to be mainly arterial in origin. In the diastolic phase, the descending part of the pulse curve can be modified by venous superpositions coinciding with the right atrial "A" wave. With increase of ICP the configuration of the CSF pulsations changes: the venous superpositions disappear and the waves become more and more arterial in shape. Furthermore, the pulse amplitude increases considerably. The same change can be observed when cerebral vessels are dilated by arterial hypoxemia. During cardiac insufficiency and consecutive increase of CVP, the CSF pulse curve is venous in shape and the right atrial "A" wabe predominates. In arterial hypotension, CSF pressure decreased. Conversely, in angiotensin-induced systemic arterial hypertension, CSF pressure and its pulse amplitude increased. It is concluded that both systemic arterial blood pressure and cerebrovascular reactivity are major determinants for the shape and the pressure amplitude of the intracranial CSF pulse waves. In the presence of cerebral vasodilatation, systemic arterial blood pressure may be an important factor in raising ICP and altering the brain tissue compliance, because cerebral vascular damping of the arterial pulse is diminished and the arterial pressure head may be directly transmitted to the cerebral capillary bed.

Animals↗
PubMed1976

The rhythm of the normal human heart.

The 24-hour cardiac rhythm was studied in 86 subjects (41 male, 45 female) aged 16-65 years, after exclusion of 15 additional volunteers with suspected abnormalities. The electrocardiogram was recorded continuously for two 24-hour periods. In this apparently normal population, 10 subjects (12%) had disturbances of rhythm which are widely believed to be of serious prognostic significance; they included frequent ventricular ectopic beats, R-on-T and multifocal ventricular ectopic beats, bigeminy, and ventricular tachycardia. Supraventricular tachycardia, infrequent ventricular ectopic beats, junctional rhythm, and second-degree heart block were also observed, and if these are included most of the subjects showed some disturbance of rhythm. Bradyarrhythmias and tachyarrhythmias were equally common in waking hours and during sleep. These disturbances were not confined to the older age-groups. Heart-rate but not the number of arrhythmias was significantly higher in smokers.

Adolescent↗
PubMed1976

Physiotherapy and the frozen shoulder: a comparative trial of ice and ultrasonic therapy.

In a prospective study ice and ultrasonic applications have been compared in a series of patients with the frozen shoulder syndrome. No significant advantage of one treatment over the other could be demonstrated. It would appear that both of these physiotherapy methods can shorten the painful stage of the condition and, in conjunction with specific exercises, hasten recovery of the range of shoulder movement.

Adult↗
PubMed1976

Observations on the pharmacokinetics of acebutolol.

Using a balance, randomized, crossover design, single intravenous (1 mg/kg) or oral (3 X 100 mg) doses of acebutolol were administered at weekly intervals to 6 healthy volunteers. For each subject venous blood samples and timed urine collections were obtained after each treatment. Plasma and urinary acebutolol levels were measured by a spectrophotometric method that measures acebutolol and its N-acetyl metabolite (which has equivalent cardiac activity). Using a computer program, various pharmacokinetic parameters were estimated from the date of each subject. From the intravenous data (obtained up to 6 hr after dosing), the following mean (+/-SD) values were found: distribution half-life (T 1/2D), 0.60 (+/-0.43) hr, plasma elimination half-life (T 1/2El), 3.2 (+/-1.1) hr, apparent volume of distribution (VD), 224 (+/-69) L, and apparent VD/kg, 3.0 (+/-0.8) L/kg. Using the oral data (obtained up to 10 hr after dosing), the value for T 1/2El was 3.2 (+/-0.9) hr. The mean cumulative urinary recovery (expressed as % dose) after the intravenous route was about 60%, while that after the oral route was of the order of 35%, suggesting that about half of the oral dose reached the systemic circulation. The mean creatinine clearance of the 6 subjects was 103 (+/-7) ml/min, while the value (obtained between 2 and 4 hr after intravenous dosing) for renal clearance of acebutolol as measured was 298 (+/-68) ml/min and the corresponding plasma clearance was 818 (+/-64) ml/min. These results support the occurrence of substantial nonrenal elimination and renal tubular secretion.

Acebutolol↗
PubMed1976

Cerebral blood flow and oxidative brain metabolism during and after moderate and profound arterial hypoxaemia.

In anaesthetized artificially ventilated dogs, the effect of graded arterial hypoxaemia on cerebral blood flow (CBF) and on the oxidative carbohydrate metabolism of the brain was tested. It is shown that the hypoxic vasodilatory influence on cerebral vessels is present even at moderate systemic hypoxaemia, provide that PaCO2 is kept within normal limits. At PaO2 of about 50 Torr, CBF increased from 56.6 to 89.7 ml/100g/min. With increasing cerebral hyperamia (CBF increased to 110.9 ml/100g/min, at PaO2 of 30 Torr), CMRO2 (4.2 ml/100g/min) was not significantly raised above its normal level (4.7 ml/100g/min) even with profound arterial hypoxaemia. This shows that CMRO2 levels are poor indices of hypoxic hypoxia. A disproportionately high increase in cerebral glucose uptake (CMR glucose levels rose from 4.4 to 10.4 mg/100g/min) and enhanced cerebral glycolysis (CMR lactate changed from 0.2 to 1.6 mg/100g/min) at moderately reduced PaO2 (50 Torr) indicated early metabolic changes which became more marked with further falls in arterial oxygen tension. However, 60 minutes after restoration of a normal PaO2 level, CBF and brain metabolism were found to have completely recovered. It is concluded that a short period of profound systemic hypoxaemia does not produce long lasting metabolic and circulatory disorders of the brain provided the cerebral perfusion pressure does not vary, and is kept at normal levels.

Animals↗
PubMed1976

Cerebral vasospasm after brain injury.

Severe vasospasm of the supraclinoidal portion of the internal carotid artery and the proximal part of the anterior and middle cerebral arteries was displayed by cerebral angiography in a 45 year old female patient who had developed progressive disturbance of consciousness and marked meningism with extremely bloody lumbar CSF within a few days after craniocerebral trauma. Aneurysm could be excluded angiographically and operatively. One and a half weeks after evacuation of a subdural haematoma and an intracerebral contusional bleeding, when the patient was discharged without any neurological deficit, control angiography showed that angiospasm had disappeared. The scanty literature on cerebral vasospasm after brain trauma is reviewed. The role of traumatic angiospasm in prognosis and the necessity for broad indications for cerebral angiography in cases with brain contusion is emphasized.

Brain Injuries↗
PubMed1976

[Parinaud's syndrome in non-tumorous hydrocephalic intracranial hypertension].

Four cases (3 children and one adolescent) are presented in which Parinaud's syndrome developed in the course of progressive non-tumorous hydrocephalus. The vertical gaze palsy completely disappeared in all cases some days after raised intracranial pressure had been successfully treated. Neuroradiological findings indicate that Parinaud's syndrome can be elicited by a dorsal midbrain compression due to a markedly dilated suprapineal recess. Other contributing factors as distortion and compression of distal branches of the posterior cerebral artery in the cisterna ambiens region and an axial caudal displacement of the oral brain stem may be involved. According to the few cases published in the literature, the vertical gaze palsy seems to occur predominantly in benign connatal aqueduct stenosis and may then be regarded as a relatively early symptom of decompensating hydrocephalic intracranial pressure.

Adult↗
PubMed1976

[The role of diastematomyelia in the differential diagnosis and treatment of kyphoscoliotic paraplegia].

By its frequent association with malformative scoliosis and neurological symptoms diastematomyelia has an important place in the diagnostic and treatment of cyphoscoliotic neurological syndromes. In all these cases and even in cases without neurological deficits the diagnosis of disatematomyelia should be done by routine myelography. The indication for operation is often curative in cases with neurological signs and prophylactic in those without.

Adolescent↗
PubMed1975

Cardiac and pulmonary effects of acebutolol.

In a double-blind randomised study, single intravenous doses of propranolol (0-1 mg. per kg.), practolol (1 mg. per kg.), acebutolol (1 mg. per kg.), or placebo were each administered at weekly intervals to six healthy volunteers. Forced expiratory volume in 1 second (F.E.V.1), resting and exercise heart-rate, and resting and exercise peak flow-rate (P.F.R.) were determined before and at 2, 3, 4, and 6 hours after each treatment. Venous blood-samples were also obtained at these times. Compared with placebo, resting heart-rate was reduced after all three drugs, but the corresponding differences in exercise heart-rate were much greater, more consistent, and of greater statistical significance. At 2, 3, and 4 hours when acebutolol and propranolol produced equivalent cardiac beta-blocking activity (judged by reductions in exercise heart-rate), their mean plasma concentratios were in the ratio of about 8/1; and at 2 hours when practolol and acebutolol gave rise to almost equivalent cardiac beta blockade, their mean plasma concentratio ration was 3/1. At times, reductions in F.E.V.1 and resting P.F.R. after propranolol (but not after practolol or acebutolol) were significantly greater than the corresponding changes after placebo. The reductions in exercies P.F.R. after propranolol (6 hours) and acebutolol (4 hours) (but not after practolol) were significantly greater than the changes after placebo. Changes in F.E.V.1, resting and exercise P.F.R. after propranolol, and the corresponding changes after practolol, were significantly different, all of which confirmed that practolol was more cardioselective than propranolo. In general, the reductions in F.E.V.1 and resting P.F.R. after acebutolol were slightly smaller than after propranolol, excepting at 6 hours when the difference between them was significant. The reductions in exercise P;F.R. after acebutolol and propranolol were of the same order, there being no significant differences between the two, whereas the reductions after acebutolol were clearly greater than the corresponding changes after practolol, the differences being significant at 2, 3, and 4 hours.

Acebutolol↗
PubMed1975

The effect of carbon dioxide on cerebral blood flow and cerebral metabolism in dogs.

In 11 normally oxygenated, normotensive mongrel dogs, blood flow and oxidative metabolism of the brain was studied during normocapnia and during respiratory alkalosis and respiratory acidosis. During respiratory alkalosis (mean PaCO2 17.8 mm Hg) CBF decreased significantly from 61.0 to 33.9 ml/100 g/min (44%) while arteriovenous-substrate differences increased and the rates of oxygen and glucose metabolism remained constant. Cerebral venous-arterial difference of lactate was increased significantly as compared with the resting state. During hypercapnia CBF increased significantly from 61.0 (resting state) to 115.7 ml/100 g/min (89%) (mean PaCO2 64.7 mm Hg). The arteriovenous-substrate differences decreased while the cerebral metabolic rates remained constant. The data show that the relationship between PaCO2 and CBF in the range 20-65 mm Hg PaCO2 is expressed by a linear relationship: y = 2.88 + 1.69x; in this range, the oxidative metabolism of the brain is unchanged and the increased cerebral lactate production in respiratory alkalosis is not necessarily linked to tissue hypoxia.

Acidosis, Respiratory↗
PubMed1975

Procainamide absorption studies to test the feasibility of using a sustained-release preparation.

Using in vitro techniques it was confirmed that whilst the release of procainamide from the conventional formulation (Pronestyl) was rapid, that from the sustained-release preparation (Cardiorytmin Retard) occurred over a prolonged period. 2 The peak plasma procainamide concentrations after single doses of Cardiorytmin Retard were relatively lower and occurred later than those after single doses of Pronestyl. Furthermore, after reaching a peak, the fall in plasma procainamide concentration was less rapid after the sustained-release preparation. Early urinary recovery of procainamide in patients and in healthy volunteers was greater after Pronestyl than after Cardiorytmin Retard, though overall recovery in urine was similar. These findings indicate that the absorption of the sustained-release preparation is slower, though the overall bioavailabilities of the two preparations are almost the same. 3 These results confirm the feasibility of using a sustained-release procainamide preparation, such as Cardiorytmin Retard, since it would be possible to administer the same amount of drug in fewer daily doses without plasma concentrations becoming ineffective towards the end of each dosing interval.

Adult↗