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Biomedical subjects

I Freiman

Publications and source records attributed to I Freiman.

At least 19 recordsLinked to original sources
PubMed2005

Cannabinoids depress excitatory neurotransmission between the subthalamic nucleus and the globus pallidus.

The globus pallidus receives its major glutamatergic input from the subthalamic nucleus and subthalamic nucleus neurons synthesize CB1 cannabinoid receptors. The hypothesis of the present work was that CB1 receptors are localized in terminals of subthalamo-pallidal glutamatergic axons and that their activation leads to presynaptic modulation of neurotransmission between these axons and globus pallidus neurons. Patch-clamp studies were carried out on oblique-sagittal mouse brain slices. The subthalamic nucleus was stimulated electrically and the resulting excitatory postsynaptic currents (EPSCs) were recorded in globus pallidus neurons. The mixed CB1/CB2 receptor agonist R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazin-yl]-(1-naphthalenyl)methanone mesylate (WIN55212-2; 3 x 10(-7) M) had no effect on EPSCs. WIN55212-2 (10(-5) M) decreased the amplitude of EPSCs by 44+/-8%. The inhibition by WIN55212-2 (10(-5) M) was prevented by the CB1 antagonist N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazolecarboxamide (10(-6) M). WIN55212-2 (10(-5) M) did not change the amplitude of spontaneous EPSCs (sEPSCs) recorded in globus pallidus neurons but lowered their frequency. Moreover, WIN55212-2 (10(-5) M) had no effect on currents elicited by direct activation of postsynaptic receptors on globus pallidus neurons by glutamate (10(-3) M) ejected from a pipette. In a final series of experiments, the firing of subthalamic nucleus neurons was recorded; WIN55212-2 (10(-5) M) did not change the firing of these neurons. The results show that activation of CB1 receptors inhibits glutamatergic neurotransmission between the subthalamic nucleus and the globus pallidus. Lack of effect of cannabinoids on the amplitude of sEPSCs and on currents evoked by direct stimulation of postsynaptic glutamate receptors indicates that the mechanism is presynaptic inhibition of glutamate release from axon terminals. Cannabinoids seem to act preferentially presynaptically: in contrast to their action on axon terminals, they have no effect on somadendritic receptors regulating firing rate. Cannabinoids elicit catalepsy in vivo. The observed inhibition of glutamatergic neurotransmission in the globus pallidus would favor catalepsy.

Animals↗
PubMed1986

Spatial and temporal variations in regional left ventricular function in isolated disease of the left anterior descending coronary artery.

The temporal and spatial pattern of left ventricular (LV) contraction and relaxation in 34 patients with isolated lesions of the left anterior descending artery (LAD) were studied from the LV cineangiogram in the right anterior oblique position using a computer interactive technique. The LV outline was divided into 100 equiangular radii from the center of the enddiastolic silhouette and the trajectory of contraction and relaxation of each radius measured and displayed. Patients were divided into different subsets. Classical anterior wall infarction caused impaired contraction of the distal two thirds of the anterior wall, the apex and the distal quarter of the inferior wall, with marked delay in contraction and relaxation of the border zones and hyperkinesis of the inferior wall. Spatial and temporal disturbances (akinesis and asynchrony) were marked in the other subsets. Left bundle branch block caused profound temporal delay particularly during relaxation.

Adult↗
PubMed1986

Left ventricular function in acute myocardial infarction: assessment by nuclear angiography.

Left ventricular function was assessed in 38 patients two to six days after acute myocardial infarction using nuclear angiocardiography and the following parameters were measured: Left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV), ejection fraction (LVEF), indices of left ventricular filling and emptying, right ventricular ejection fraction and ejection rate. Their clinical significance was assessed by their relationship to the patients site and size of infarction, functional capacity, morbidity and mortality. The most sensitive indices of depressed left ventricular function were the EF and ESV. Thus, function was preserved in patients with a small inferior infarction (LVEF = 0.57 +/- 0.07, LVESV = 69 +/- 14 ml) and in Killip Class I (LVEF = 0.48 +/- 0.13, LVESV = 80 +/- 20 ml). Function was disturbed most in patients with extensive anterior infarction (LVEF = 0.18 +/- 0.12, LVESV = 131 +/- 46 ml), Killip Class IV (LVEF = 0.13 +/- 0.07, LVESV = 160 +/- 35 ml), cardiogenic shock (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 35 ml), pulmonary edema (LVEF = 0.11 +/- 0.06, LVESV = 166 +/- 25 ml) and pulmonary capillary wedge pressure greater than 20 mm Hg (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 33 ml). Previous infarction was associated with LV dilatation and a greater LVEDV. A lower ejection fraction signified a large infarct and poor left ventricular function. If the ejection fraction was less than 0.15, the patients were unlikely to leave the hospital alive, or if less than 0.25, they were left with poor residual ventricular function and either had significant cardiac failure or high late mortality. Nuclear angiocardiography was a simple method of predicting the clinical pattern and prognosis in each patient and emphasized the importance of limiting infarct size in acute myocardial infarction.

Adult↗
PubMed1986

Atrial fibrillation in acute myocardial infarction.

Atrial fibrillation (AF) complicating acute myocardial infarction (AMI) is associated with increased morbidity and mortality. Early intervention with antiarrhythmic treatment and hemodynamic support in patients prone to develop AF may modify their course. The purpose of this study was to characterize on admission the patients with AMI who are prone to develop AF. The admission data of 45 consecutive patients who developed AF during the course of AMI, and the data of a control group of 45 consecutive patients with AMI who did not develop AF, were analyzed using logistic regression. The following characteristics of patients who developed AF were identified: old age, history of heart failure prior to admission, low systolic blood pressure on admission, wide P waves, presence of left bundle branch block or left anterior hemiblock, marked ST segment elevation, and PQ segment depression (admission ECG). The logistic regression formula correctly classified 80 of the 90 patients (89%) to their actual group. The study showed that the relative risk of a patient with AMI to develop AF can be estimated on admission from simple, readily available, clinical data.

Aged↗
PubMed1984

Two-channel ECG monitoring in the coronary care unit.

We describe the installation and clinical application of a two-channel monitoring system in the intensive coronary care unit using a single patient cable and two exchangeable ECG modules. Routine use of this system during a period of three years has shown that it has many advantages in the precise documentation and diagnosis of transient cardiac arrhythmias and for the recognition and localization of ischemic episodes.

Arrhythmias, Cardiac↗
PubMed1983

Intravenous verapamil therapy in imminent myocardial infarction.

We studied 16 patients with small myocardial infarction who had further episodes of chest pain with ST-segment elevation, a sign of transmural myocardial ischemia and imminent infarction extension. Coronary angiography in 14 showed a critical lesion in 13. Intravenous verapamil abolished chest pain and ST-segment elevation. It caused a fall in right atrial and left ventricular end-diastolic pressures (LVEDP) and cardiac output, reflex systemic vasoconstriction, and a rise in systemic vascular resistance. There was no reflex tachycardia. Volume expansion raised LVEDP and restored a normal cardiac output. Accelerated junctional rhythm with isorhythmic A-V dissociation occurred in 5 patients. Two patients sustained a transmural infarction, 10 underwent coronary artery bypass grafting, and 4 are symptom-free with oral treatment. Intravenous treatment was an effective method of treating acute episodes of transmural myocardial ischemia and preventing their recurrence in patients with critical coronary artery narrowing. Continuous verapamil infusion stabilized the patients' condition and enabled smooth coronary angiography and induction of anesthesia for surgery.

Aged↗
PubMed1982

Serum phosphorus in protein energy malnutrition.

Phosphorus depletion in malnutrition has not generally received attention. Serum phosphorus was measured in healthy infants (1.8 mmol/L), in well-nourished infants with acute dehydrating gastroenteritis, and in infants suffering from malnutrition. Serum phosphorus levels were found to be low in well-nourished infants with acute dehydrating gastroenteritis (1.32 mmol/L) an exceptionally low in infants with kwashiorkor (1.10 mmol/L) especially when the latter condition was accompanied by severe diarrhoea (0.66 mmol/L). Hypophosphatemia, as well as hypokalemia, was associated with marked hypotonia. Low levels of serum phosphorus occurred in nine of the 10 malnourished children who died.

Child, Preschool↗
PubMed1982

Intraaortic balloon counterpulsation in acute myocardial infarction.

Intraaortic balloon counterpulsation was undertaken in 24 patients with acute myocardial infarction. The patients were divided into four groups: severe left ventricular dysfunction (11 patients), mechanical lesions (6), intractable angina pectoris (6) and refractory ventricular tachycardia (1). The clinical condition and the hemodynamic measurements improved dramatically in 21 patients, but there were only 9 long-term survivors. Intraaortic balloon counterpulsation gave the best results in patients with preinfarction angina pectoris or patients with left ventricular dysfunction where the hemodynamic status deteriorated after an acute but reversible cardiovascular event. Numerous local complications were observed.

Adult↗
PubMed1980

Summer diarrhoea in African infants and children.

Of 70 black South African infants and children with acute summer diarrhoea, 30 (43%) were infected with enteropathogenic serogroups of Escherichia coli (EPEC), 13 (19%) with enterotoxigenic Gram-negative bacilli, 12 (17%) with Salmonella sp., 6 (9%) with Shigella sp., and 3 (4%) with rotaviruses. 13 (19%) patients were infected simultaneously with more than one enteropathogen, and no pathogen was detected in 22 (31%). In addition, 6 (15%) of 41 unselected patients were excreting Campylobacter fetus. Of 30 age-matched controls drawn from the same population, 5 (17%) were infected with EPEC serotypes, and 1 each with Salmonella sp. and rotavirus. This study stresses the polymicrobial nature of paediatric diarrhoea in a developing community and shows the continued importance of EPEC in this setting.

Campylobacter fetus↗
PubMed1979

Long-term effects of kwashiorkor on the electroencephalogram.

The long-term effects of kwashiorkor on the electroencephalogram were assessed by means of computer analysis techniques. The experimental group, consisting of 30 black children, 6 to 12 years old, hospitalized for the treatment of kwashiorkor during the first 27 months of life, was age-matched with three control groups. These were a group of siblings and of yardmates, neither of whom had been exposed to acute infantile malnutrition, and a very high socioeconomic group of white children. The results revealed significantly less alpha activity and more slow-wave activity in the electroencephalogram of the kwashiokor group than in those of the control groups. These findings confirmed previous results based on visual analysis procedures.

Alpha Rhythm↗
PubMed1979

Detection of enteric campylobacteriosis in children.

Campylobacter fetus subsp. jejuni was recovered as the sole bacterial pathogen from 31% of 0- to 8-month-old children with acute gastroenteritis and from 5% of asymptomatic children (P less than 0.05). In children 8 to 24 months old, the respective recovery rates were 38 and 40%. With the exception of one case of simultaneous bacteremia, the clinical course of the symptomatic infection was benign and rarely lasted more than a week. The isolates were sensitive to most commonly used antibiotics. Several isolates shared antigenic determinants with C. fetus subsp. intestinalis. A bacteriophage specific for C. fetus subsp. jejuni lysed 73% of the strains. Several phage-resistant isolates carried a phage that lysed the stock strain of C. fetus subsp. jejuni (NADC 917).

Anti-Bacterial Agents↗
PubMed1979

Alexander's disease: case report including histopathological and electron microscopic features.

We report a case of Alexander's disease in a black South African boy of 9 years. The child presented with a grossly abnormal stooped posture, generalised weakness, and slurred nasal speech. Computerised tomography revealed diffuse low radio-density confined to the white matter, and enlarged ventricles. Cerebral biopsy confirmed the diagnosis. The histopathological and electron microscopic features are essentially the same as those described in previous reports. We note the presence of dense clumps of material within some of the Rosenthal fibres, and can find no reference in the literature describing this. Sural nerve biopsy was normal.

Astrocytes↗
PubMed1978

The visual evoked potential in children after kwashiorkor.

An index of the long-term effects of kwashiorkor on the electrocortical development of the child was obtained by recording the visual evoked potential (VEP) of 4 groups of children aged 6--12 years. The malnourished group, consisting of 30 Black children hospitalized for treatment of kwashiorkor during the first 27 months of life, was age-matched with 3 control groups. Some evidence of right hemisphere VEP deficit was found in the kwashiorkor group.

Child↗
PubMed1978

Emergence of multiply resistant pneumococci.

Multiple antimicrobial resistance in pneumococci was detected in Johannesburg in July, 1977, and prompted an investigation of the prevalence of resistant strains in two hospitals. Carriers of Types 6A and 19A penicillin-resistant pneumococci, resistant to antibiotic concentrations ranging between 0.12 and 4 microgram per milliliter were found in 29 per cent of 543 pediatric patients and 2 per cent of 434 hospital staff members. Multiply resistant Type 19A strains, resistant to beta-lactam antibiotics, erythromycin, clindamycin, tetracycline and chloramphenicol, were isolated from 128 carriers, and were responsible for bacteremia in four patients. Isolates from 40 other carriers were resistant to penicillin alone or to penicillin and chloramphenicol or to penicillin, chloramphenicol and tetracycline. Pneumococci can be screened for penicillin resistance with a modified Kirby--Bauer technic; the strains with zones of less than 35 mm around 6-microgram penicillin disks or less than 25 mm around 5-microgram methicillin disks should be tested for sensitivity to penicillin by measurements of minimum inhibitory concentration.

Adult↗
PubMed1978

Epidemic listeriosis. Report of 14 cases detected in 9 months.

During the period August 1977 to April 1978, 14 Black patients in Johannesburg area had systemic infections caused by Listeria monocytogenes. Nine of these patients were neonates who presented with septicaemia (5 cases) or septicaemia and meningitis (4 cases) and 5 were adults, all of whom had meningitis. The mortality rate was 43% (6/14), with 4 neonatal and 2 adult deaths. All isolates of L. monocytogenes were type 4b. Only sporadic cases of human listeriosis have previously been reported in South Africa, and the cases reported here constitute the first epidemic in this country.

Adult↗