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Biomedical subjects

C Levy

Publications and source records attributed to C Levy.

At least 19 recordsLinked to original sources
PubMed1992

[Discordant heart xenografts. Experimental study in pigs conditioned by total lymphoid irradiation and cyclosporine A].

The use of discordant xenografts may solve some of donor shortage problems. The beneficial effects of treatment with total lymphoid irradiation (TLI) and classical drugs on this discordant model of transplantation rejection was evaluated. Twenty-four lamb hearts were transplanted heterotopically in the abdomen of 24 pigs. Group I received no treatment (control). Group II received continuous intravenous medical treatment cyclosporin A (CyA) (5 mg/kg) and azathioprine (3 mg/kg) 3 days prior to transplantation. Group III received the same medical treatment and simultaneously 12 grays of irradiation in 5 equal fractions with a high rate (100 cGy/min) or a low rate (1.6 cGy/min) prior to transplantation. Group IV also received 12 grays in 5 fractions at a high rate followed by the medical treatment started 5 days after TLI and continued until the day of transplantation. Antibody and serum cyclosporine levels were monitored. Histology specimen were analyzed at the end of the experiment. Mean GST (graft survival time) in group I and II was 140 +/- 35 min and 117 +/- 27.4 min respectively. The histological features of these hearts suggested acute humoral rejection (hemorrhage, thrombosis, and edema) without cellular infiltration. In group III, one heart functioned 4.5 days with pathological features of cellular rejection and a second animal died at 6 hours with a functioning graft with no evidence of an acute rejection. Both had been treated with the low rate TLI protocol (1.6 cGy/min). The mean GST in this group was 1080 +/- 794 min. In Group IV, one graft functioned for 6.5 days and another for 3.25 days. Mean GST was significantly increased in this group to 4800 +/- 2647 min (p < 0.05). A cellular infiltration was seen in this two grafts. The remaining graft was rejected in 6 hours with histological lesions typical of acute humoral rejection. Antibodies levels at the time of transplantation were lowest (40%) in group IV and in the low rate irradiation group. The ability of TLI to induce tolerance and to prolong survival in a discordant xenograft model depends upon cumulative dose, rate of irradiation, delay between TLI and graft placement, and combined treatment with immunosuppressive drugs. A high rate of TLI and graft placement is delayed. Low rates of irradiation may be beneficial when there is a very short period between treatment and transplantation. These findings highlight the potential usefulness of TLI in combination with immunosuppressive drug therapy when antibody-mediated rejection occurs, such as with xenograft and in sensitized patient.

Animals↗
PubMed1992

Occurrence of Ixodes pacificus (Parasitiformes: Ixodidae) in Arizona.

Adults and immatures of Ixodes pacificus Cooley & Kohls were collected by flagging vegetation and from lizards during a 3-mo period in the Hualapai Mountain Park, Mohave County, AZ, in 1991. Collections were made at altitudes > or = 2,134 m. Two of 48 gut-salivary gland extracts of adult ticks were positive by IFA using a monoclonal antibody (H5332) specific to Borrelia burgdorferi. These are the first records of I. pacificus and of spirochetes tentatively identified as B. burgdorferi in Arizona.

Animals↗
PubMed1992

[Unusual localization of an olfactory esthesioneuroma].

Olfactory neuroblastoma, a nerve tumour arising in the olfactory mucosa, is a relatively easy diagnosis in the case of a mass centered around the cribriform plate. It is more difficult to diagnose in its exceptional ectopic forms (maxillary sinus) in the absence of any cytological and histochemical arguments (fibrils, olfactory rosettes). Its local malignancy is variable with a 42% 5-year survival for stage C and metastases in 30% of cases (principally cervical nodes, bone and liver). The role of imaging is to define the criteria of a mass syndrome and to perform the preoperative staging in a case of apparently simple sinus obstruction.

Brain Neoplasms↗
PubMed1992

[Preoperative embolization of cervical bone metastasis with radio-controlled direct puncture].

Surgery of vertebral hypervascular metastasis can take advantage of preoperative embolization to make the surgical procedure easier to perform. Usually, embolizations are executed by vascular tract. We report a case of one cervical metastasis located in C4 for which embolization was executed with direct puncture of the vertebra. This method has the advantage to be feasible whatever tumoral vascularization, and more particularly in case of departure of radiculo-medullary artery or any other cephalic vessel from the tumoral site.

Biopsy, Needle↗
PubMed1992

[Gardner syndrome: possibility of early detection of carriers by examination of the ocular fundus?].

Through indirect ophthalmoscopic examination it was possible to analyse three families originated from the same Swiss alpine valley (Poschiavo) and carrying Gardner syndrome (SdG) to check if their members with SdG were presenting hypertrophic changes of the retinal epithelium which is supposed to be an early symptom of that syndrome. This lesion was found to be present only in two out of 11 patients (18%) with at least one symptom of SdG. Because of its lacking sensitivity, ophthalmoscopic examination is not able to substitute colonoscopy as a valid screening method to find out which members of a SdG-family are at risk to develop colonic poliposis and cancer.

Chromosome Aberrations↗
PubMed1991

Stage I-II squamous cell carcinoma of the oral cavity treated by iridium-192: is elective neck dissection indicated?

This is a retrospective analysis of 233 evaluable patients with stage I-II squamous cell carcinoma of the oral cavity treated by definitive branchytherapy. Minimum follow-up is 3 years. Treatment of neck was chosen by a multidisciplinary team, according to age, medical status and availability for regular follow-up. One hundred and ten patients (47%) underwent elective neck dissection (END); 28 (25%) had positive nodes and received neck irradiation post-operatively. One hundred and twenty three patients (53%) were regularly followed up only, with therapeutic neck dissection (TND) reserved for cases of node relapses. In the END group, there were 19 neck relapses (17%): 12/60 (20%) in patients with mobile tongue carcinoma and 7/50 (14%) in patients with floor of the mouth carcinoma. Salvage treatment was successful in 9/19 (47%) cases. In the TND group, there were 21 neck relapses (17%): 16/82 (20%) in patients with mobile tongue carcinoma and 5/41 (10%) in patients with floor of the mouth carcinoma. Salvage treatment was successful in 13/21 (62%) cases. Ten-year survival is 37% for the END group and 31% for the TND group. Tumour stage and infiltration into underlying tissues increased the probability of neck relapse and death. Furthermore, a multivariate analysis showed that patients treated in the TND group had a higher probability of death than patients treated in the END group (p less than 0.04).

Adult↗
PubMed1991

[Conflicting xenograft. Role of preoperative total lymphoid irradiation].

This study deals with an experimental model of discordant cardiac xenograft between 24 donor lambs of the Préalpes race and 24 recipient Camborough pigs divided up into 4 groups: I control (6) without immunosuppressive treatment; II (5) with pharmacological immunosuppression (IP); III (13) with PI and total lymphoid irradiation (TLI) and immediate graft, divided up into IIIa (5) with high-rate (HR) TLI and IIIb with low-rate (LR) TLI; IV (4) with a two-week lapse between TLI and grafting. The best graft survival rate (GSR) is obtained either after delayed LR-TLI or after LR-TLI without delay. This study seems to be the first one demonstrating that for discordant xenogenic grafts, TLI associated to PI with cyclosporin A (Cy A) significantly prolongs the survival of the graft (30 times).

Animals↗
PubMed1991

Nocardia asteroides infection following scleral buckling.

We report a case of delayed external ocular Nocardia asteroides infection following scleral buckling for rhegmatogenous detachment. Surgical removal of the exoplant material allowed isolation and identification of the organism. Topical and systemic antibiotic therapy following exoplant removal yielded a favorable result.

Aged↗
PubMed1990

Ethanol and opiate decrease the axonal transport of substance-P like immunoreactive material in rat vagus-nerves.

Since an enhanced retrograde axonal transport of receptor-bound opiate was observed in the ligated vagus nerves of rats treated chronically with alcohol, we decided to look at the anterograde axonal transport of substance P in the same experimental conditions and, after opiate administration. From 1 day up to 24 days' treatment with alcohol, we observed a decrease in the accumulation of substance P like immunoreactive material (SPLM) in rat ligated vagus nerves. Acute administration of lofentanil, an mu opiate agonist, caused the same reduction of anterograde axonal transport of SPLM and this effect could be prevented by naloxone. When naloxone or bezitramide, an opiate agonist, was given during the alcoholization period, the preference for alcohol in a choice test was reduced or prevented suggesting that opioid peptides are probably involved in chronic alcoholism. The present results support the idea that a common denominator could exist in drug addition and in chronic alcoholism and that substance P may be directly or indirectly involved.

Analgesics↗
PubMed1990

Axonal transport of synaptic vesicles and muscarinic receptors: effect of protein synthesis inhibitors.

The effect of cycloheximide, a protein synthesis inhibitor, was studied on the axonal transport of noradrenergic synaptic vesicles and presynaptic muscarinic receptors, identified by in vitro binding of [3H]dihydrotetrabenazine and [3H]quinuclidinylbenzilate, respectively, in rat sciatic nerve. Cycloheximide (1.5 mg/kg) administered subcutaneously 2 h before ligation decreased by approximately 50% the accumulation of vesicles and receptors in the proximal segment above the ligature placed on the nerve; its action was detectable after a lag period of 10 h and disappeared 96 h after administration. Double ligatures were placed on the nerve at various time intervals between the first (distal) and the second (proximal) ligature, and the accumulation of vesicles and receptors proximal to the second ligature was measured; the first ligature diminished the accumulation above the second ligature. At an interval of 96 h between the first and the second ligature, cycloheximide completely prevented the accumulation of vesicles and receptors proximal to the second ligature. The effects of double ligatures and the response to cycloheximide treatment can best be explained on the assumption that an important proportion of synaptic vesicles and presynaptic receptors is being recycled in the nerve cell bodies after retrograde transport.

Animals↗
PubMed1990

Plasma levels of 3-methoxy-4-hydroxyphenylglycol in depressed patients compared with normal controls.

Plasma levels of total 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured in a group of 104 hospitalized depressed patients and a group of 104 age- and sex-matched normal controls. Plasma MHPG levels were found to be normally distributed in both groups and significantly lower in depressives than in controls. However, this difference could be related to an increase in plasma MHPG levels with age found in controls (r = 0.601, d.f. = 102, p less than 0.01) but not in depressives (r = 0.013, d.f. = 102, NS). Men had significantly higher levels than women in both groups. There was no significant difference in plasma MHPG levels among any DSM-III-R diagnostic subgroups of depressives or between patients who were suppressors on the dexamethasone suppression test and those who were nonsuppressors. Significant correlations were found between AMDP Depression Rating Scale item and total scores and levels of plasma MHPG. Age, sex and clinical symptoms appeared to be main sources of variance in studying depressed patients and comparing them with normal controls.

Adult↗