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Biomedical subjects

R Haddad

Publications and source records attributed to R Haddad.

At least 109 records · Page 6Linked to original sources
PubMed1985

Morphology, organelles and susceptibility to viruses of cultured ferret cells.

Cells explanted from a normal 6-week-old ferret's brain have been subcultured over 100 times, have undergone over 400 population doublings, possess ferret-specific antigens and are referred to as Mpf cells. Low passage-level Mpf cells formed diffuse colonies with ill-defined borders which had a swirling 'finger-print' pattern whereas the colonies formed by high passage-level cells were more densely populated and had distinct borders. Mpf cells at their 100th passage level appeared as a loose monolayer with ill-defined cytoplasmic borders and contained microfilaments, ovoid nuclei, granular endoplasmic reticula with large dilated cisternae filled with an amorphous medium electron-dense product, abundant free ribosomes, irregular and hypertrophic Golgi bodies, mitochondria, and lipid inclusions associated with lipofuscin deposits. Chains of vesicles, 120-150 nm in diameter, some opening to the exterior, were aligned at the cytoplasmic border. The Mpf cells exhibited cytopathology and synthesized progeny virus when exposed to representatives of the Arboviruses, Arenoviruses, Paramyxoviruses, Poxviruses, Retroviruses and Rhabdoviruses.

Animals↗
PubMed1984

[Antiarrhythmic effect and side effects of amiodarone].

UNLABELLED: Amiodarone (AM) is one of the most potent antiarrhythmic drugs, the value of which is limited by reversible and irreversible side-effects (SE). 59 patients, 50 male, 9 female (age 33 to 81 years) entered the study with ventricular tachycardia (VT, 68%), WPW-tachycardia (12%), non-sustained VT (12%) or untreatable paroxysmal atrial fibrillation or supraventricular tachycardia (8%). Prior to AM the patients had received 1 to 8 different antiarrhythmic drugs (m 3.5) and maximal 9 different combinations of antiarrhythmics. The drug regimen started with a loading dose of 1200 mg/d for 1 to 2 weeks and was continued with a maintenance dose of 200 to 600 mg/d. The patients were followed up 1 to 41 months (m 14 m). The drug effect was evaluated using clinical criteria (recurrence of arrhythmias, death), computer-assisted analysis of several 24 hr long-term ECGs and programmed electrophysiological stimulation. Three- to six-monthly the patients were seen in our outpatient department for check up and blood-sample analysis (liver, thyroid gland etc.). Also in the majority of the patients frequent ophthalmological and dermatological investigations, as well as lung functions tests were carried out. RESULTS: under AM therapy the initial arrhythmias were no longer detectable in 41% of the patients. In 37% a significant amelioration of the formerly life-threatening arrhythmias was found. 7 patients (12%), predominantly with reduced left ventricular function, died during follow up. No pulmonary, hepatotoxic or neurological SE were found. All patients developed reversible AM keratopathy. In 27% ETR and T4 were elevated, but only one patient developed hyperthyroidism with an increase in TT3. Another patient showed signs of hypothyroidism with an elevated TSH prior to TRH stimulation. Increased phototoxicity was found in 31%, whereas in two patients typical AM hyperpigmentation occurred, especially on the face. In conclusion, AM is a highly effective antiarrhythmic agent, despite a negatively selected collective, but it should only be used in patients with refractory arrhythmia in view of the SE.

Adult↗
PubMed1984

EEG and seizure threshold in normal and lissencephalic ferrets.

Changes in EEG and susceptibility to electrically induced seizures were examined in the ferret with lissencephaly produced by exposure to a single injection of methylazoxymethanol acetate (MAM Ac) given to the pregnant jill on gestation day 32. Ten lissencephalic and 11 normal ferrets were chronically implanted with 14 cortical stainless steel electrodes. EEG records were sampled from various stages of the sleep/awake cycle. Six of each group were subjected to electrical stimulation for seizure threshold. Although the number of stimulations and the current intensity required to produce epileptiform afterdischarges (AD) and seizures were not different between the two groups, the lissencephalic ferrets had significantly longer AD and seizures, and a greater number of generalized seizures, indicating an enhanced seizure susceptibility. The EEG of the lissencephalic ferrets was characterized by increased slow wave activity within the low theta band range, extreme spindle activity, focal or multifocal slow and sharp waves, spikes, or spike and slow wave complexes. The differences in the EEG were more pronounced during drowsiness and sleep stages. The brains of all of the treated animals were lissencephalic and hydrocephalic, and weighed significantly less than those of the normals. The cerebral cortex was thin and flattened, with the parieto-occipital region most severely affected. Heterotopic foci were found in the cerebellum as well as in the cerebral cortex. Abnormalities in the configuration of the cerebellar folia were also seen. Comparison between the electrophysiological and neuropathological data suggests that the extent of the extreme spindle activity, and longer AD and seizure duration depended on the degree of cerebellar dysplasia, whereas the EEG focal abnormalities were related to lesions in the cerebral hemispheres.

Animals↗
PubMed1984

[Hand burns in children. Retrospective study of 137 cases from 1973-1982 representing 177 hands].

One hundred and seventy seven burnt hands observed in children during the last ten years were reviewed at our hospital. One third were severely injured with burns deeper than 2nd degree. The infrequent greasy occlusive dressing was performed under general anesthesia in 87% of the burnt hands as the primary treatment. Out of 19 cases, five necessitated a secondary procedure one year or more later. Excision followed by full thickness skin grafts or flaps was used initially in 11%. Besides the common sequelae of burnt hands, we found some proper to children: clinodactyly, inhibition of longitudinal growth following epiphyseal plate destruction. The annual increase in the observed number of cases which doubled in ten years, shows the importance of prevention.

Adolescent↗
PubMed1983

Persistence of visna virus in cultured ferret brain cortex and fibroblasts.

Cerebral cortex tissue fragments from newborn ferrets have been cultured in vitro and, when exposed to visna virus, failed to exhibit a cytopathic effect but retained the genome of the virus in a quiescent state for 46 d before synthesizing plaque-forming virus for the subsequent 26 d. In contrast, infection of an established line of cells derived from a ferret's brain with visna virus resulted in the formation of the polykaryocytes typically produced by this virus and a limited synthesis of plaque-forming virus. Ferret cerebral cortex cultures may be suitable in vitro hosts for studies to define the virus-host interactions that result in virus-induced demyelination.

Animals↗
PubMed1982

Neurotransmitter chemistry of lissencephalic cortex induced in ferrets by fetal treatment with methylazoxymethanol acetate.

Treatment of pregnant ferrets with 15 mg/kg of methylazoxymethanol acetate (MAM) at 33 days of fetal gestation results in offspring with cortical hypoplasia and lissencephally. Neurochemical analysis of 5 areas of cortex from 8-week-old offspring of MAM- or vehicle-treated jills indicated an overall enrichment in markers for catecholaminergic (tyrosine hydroxylase, norepinephrine) and cholinergic (choline acetyltransferase, acetylcholine) terminals but minimal change in the concentration of GABAergic markers (glutamate decarboxylase, gamma-aminobutyric acid); however, there did not appear to be a direct, inverse relationship between the concentration of catecholaminergic and cholinergic markers and the degree of hypoplasia in cortical subareas unlike what has been found previously in the rat.

Animals↗
PubMed1981

[The effect of neural mediation on the immediate rise in intraocular pressure in glaucomatous eyes after cyclocryotherapy (author's transl)].

As a rule, there is a transient rise in intraocular pressure following cyclocryotherapy. The preoperative administration of retrobulbar anaesthesia to a group of patients significantly reduced intraocular pressure after cyclocryotherapy in this group as compared with a control group without anaesthesia. These results imply that the temporary rise in intraocular pressure after cyclocryotherapy is mediated by a neural pathway.

Ciliary Body↗
PubMed1981

Mediation of the ocular response to cyclocryocoagulation.

The possible roles of prostaglandins and a neural pathway in the disruption of the blood-aqueous barrier in the rabbit eye after cyclocryocoagulation were studied. Both the preoperative IV administration of the prostaglandin inhibitor acetylsalicylic acid and the application of retrobulbar and topical anesthesia reduced IOP and decreased breakdown of the blood-aqueous barrier, as measured by protein in the aqueous humour. These results imply that the acute response of the animal eye to cyclocryocoagulation is mediated partly by prostaglandins and partly by a neural component resistent an inhibitor of prostaglandin synthesis. When administered together, acetylsalicylic acid and ocular anesthesia yielded a further reduction in postoperative reactions and protein concentrations in the aqueous humour, but were unable to abolish the ocular response completely. The dual ocular mediation to cyclocryocoagulation is apparently due to the combined thermal and mechanical injury caused to ocular structures which synthesize prostaglandins and receive sensory innervation from the trigeminal nerve. The considerable breakdown of the blood-aqueous barrier in cyclocryocoagulation allows leakage of different molecular weight proteins, in equal ratio, into the aqueous humour.

Animals↗
PubMed1981

[Arden test for early glaucomatous damage (author's transl)].

With the aid of the Arden grading test 27 eyes with early glaucomatous visual field defects and 80 normal control eyes were examined in a double-blind study. Eighteen eyes with early glaucomatous visual field defects had values which were clearly higher (83-130) than the control eyes. In nine of the diseased eyes Arden scores were 68-82, i.e., similar to those obtained in the normal eyes.

Glaucoma↗
PubMed1981

[Timolol in the treatment of glaucoma (author's transl)].

Untolerated or insufficiently effective Therapy in 32 patients (63 eyes) with primary open-angle glaucoma was discontinued and substituted with Timolol, and all patients were followed up over a period of 60 weeks. Timolol was well tolerated in all cases without any local or systemic side effects. Either alone or in combination with other medications Timolol brought about an adequate reduction in intraocular pressure in eyes which hitherto had no longer responded to conventional conservative therapy.

Follow-Up Studies↗
PubMed1981

Decompensation of chronic open-angle glaucoma following mydriasis-induced pigmentary dispersion into the aqueous humour: a light and electron microscopic study.

A patient with well controlled chronic open-angle glaucoma developed after dilatation of both pupils persistent increase in intraocular pressure (IOP) due to extensive pigmentary dispersion into the aqueous humour. Trabeculectomy specimens obtained from both eyes after 3 and 7 weeks were studied by light and electron microscopy. It seems evident that the initial phase of raised IOP was caused by a clogging mechanism to the outflow channels by melanin and phagocytic cells. The permanent increase in IOP is attributed to the damage induced in the fibrous components of the trabecular sheets as a result of a complete breakdown of their endothelial covering.

Aged↗
PubMed1981

[Cyclocryotherapy. Experimental studies of the breakdown of the blood-aqueous barrier and analysis of a long term follow-up study (author's transl)].

We report on experimental results concerning the breakdown of the blood-aqueous barrier following cyclocryotherapy (CTh). The various factors (tip of the cryoprobe, simple or repeated application, pretreatment with prostaglandin-synthetase inhibitors and with phenylephrine, grade of pigmentation and preoperative inflammation of the anterior uvea) were studied, which influence the immediate increase in intraocular pressure (IOP) and the rise in protein concentrations in aqueous humour after the procedure. Early and late histological findings after CTh. were described. Fifty-two patients (60 eyes) with different types of chronic glaucoma were treated with CTh. and followed up for a period ranging from 7 to 44 months (mean 22.9 months). During this period IOP was maintained under 22 mm Hg in 60% of all cases. Best results were achieved with patients suffering from open-angle glaucoma (75%), worst with juvenile glaucoma (50%). Cryocoagulation of one half of the ciliary body yielded goods results in only 35%, whereas cryotherapy of the second half lead to a decrease in IOP in further 78%. Nine eyes developed persistent hypotony, of these, 2 became phthisical. Factors other than extensive coagulation may also contribute to chronic hypotony. The results of our experimental and clinical observations imply that the treatment schedule (temperature, time and number of applications, dimension of the cryode) chosen for our patients is a comparatively safe procedure with regard to the complications and yields good results as far as the reduction of IOP is concerned.

Aged↗
PubMed1981

The thymus and myasthenia gravis.

The relationship between the thymus and the pathogenesis of myasthenia gravis is reviewed. Ten cases of myasthenia gravis who underwent thymectomy at the American University Hospital of Beirut are presented. The various pathologic features of the thymus encountered in myasthenia gravis are presented. The indications for thymectomy and the results of surgical intervention on the course of the disease are reviewed. The conclusion is made that thymectomy should be done on all patients with generalized myasthenia gravis irrespective of age, sex, duration of disease or pathological features of the thymus.

Adolescent↗
PubMed1980

Cyclocryokoagulation. Sequelae of induced alterations and effect of a prostaglandin-inhibitor on the breakdown of the blood-aqueous barrier.

Histopathological changes following cyclocryokoagulation in a group of rabbits pretreated with acetylsalicyclic acid (ASA) were studied and compared with similar changes in a control group. As observed clinically, macroscopical and histological differences were only noted in the early phase after the procedure. In this phase, all operated eyes revealed an immense vascular response with edema, exudation and extravasation of blood cells. The treated animals, however, showed some reduction of tissue edema than the animals not treated. At a later stage there is an necrosis of the stroma with reduction of small vessels and tissue cells. The reparative process, tending to restore both epithelial and stromal lesions, begins already in the 3rd. week after cyclocryokoagulation. Neither the epithelial nor the stromal alterations differed significantly in any of the operated eyes at this stage. This indicates that ASA mainly affects an obviously prostaglandin-mediated acute vascular response. The disruption of the epithelial barrier may be aggravated by the subsequent stromal alterations, but does not seem to be influenced by ASA.

Animals↗