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Biomedical subjects

G Kenet

Publications and source records attributed to G Kenet.

At least 19 recordsLinked to original sources
PubMed1997

Central nervous system involvement at diagnosis in a case of pediatric CD30+ anaplastic large cell lymphoma.

Central nervous system (CNS) involvement in Ki-1/CD30 lymphoma is extremely rare, in contrast to the frequent involvement in other types of pediatric non-Hodgkin's lymphoma. No mechanism has yet been proposed to explain the sparing of the blood brain barrier in Ki-1/lymphoma. We present a 2-year-old boy who was admitted to the Department of Pediatric Hemato-Oncology due to lethargy, progressive breathing difficulties, massive diffuse lymphadenopathy, hepatosplenomegaly, and ichthyosis-like skin involvement with epidermolysis. A lymph node biopsy was compatible with Ki-1/CD30 anaplastic large cell lymphoma (ALCL). Bone marrow aspirate and biopsy demonstrated reactive hyperplasia. Cytogenetic analysis displayed hyperdiploid cells with 1p(-) in most cells. Cerebrospinal fluid examination showed pleocytosis with CD30+ cells. Possible mechanisms which could enable CNS involvement in this unusual case are discussed.

Central Nervous System Neoplasms↗
PubMed1997

Methimazole slows hepatocyte streaming in rats.

Hepatocytes are hypothesized to continually stream from the portal tract to the terminal hepatic vein. By this model, when a cell divides, one of its progeny replaces the dividing ancestor and the other is displaced into a more remote location. The present experiment aims to demonstrate that hypothyroidism affects liver cell turnover. Thirty male adult rats were divided into two groups. One received methimazole for two weeks and the other served as control. Each rat was injected intraperitoneally with 18.5 KBq [3H]thymidine/g body weight. Rats were killed after 1 hr and two and four weeks. Autoradiography was done. The distance of the labeled cells from the portal tract was measured. The mean TSH levels of the methimazole-treated group and controls were 1.45 and 0.25 mM/liter, respectively (P < 0.01). Hepatocyte streaming was lower in hypothyroid (1.8 microns/day) than in untreated rats (2.5 microns/day) (P < 0.01). The respective labeling indices 1 hr after labeling were 0.9% and 1.24% (P < 0.05). We conclude that hypothyroidism diminishes hepatocyte and littoral cell turnover and slows down their streaming.

Animals↗
PubMed1997

Anti-thyroid drugs decrease mucosal damage in a rat model of experimental colitis.

BACKGROUND: Methimazole, an anti-thyroid drug, was recently found to be useful in the treatment of systemic lupus erythematosus and other autoimmune diseases. Moreover, decreased thyroid hormone production is associated with a variety of immunological manifestations, such as reduced activation of CD4+ cells, increased CD8+ cell activity and reduced soluble IL-2 receptors. In the present study we examined the effects of methimazole and propylthiouracil on a rat model of experimental colitis. METHODS: Colitis was induced by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB). Two weeks prior to induction of colitis, rats were treated by either methimaziole (0.04%) or propylthiouracil (0.01%) in drinking water after a week of free access to water. Rats were sacrificed 48 h or 7 days after induction of colitis. The colon was isolated, rinsed with ice-cold water and weighed. Damage was assessed both macroscopically and microscopically and myeloperoxidase (MPO) activity determined. RESULTS: All treated rats were hypothyroid as manifested by a significant elevation of thyroid stimulating hormone (TSH), by comparison with the control groups (mean -1.82 +/- 0.40 versus 0.11 +/- 0.02 mmol/L, respectively). The inflammatory response elicited by TNB resulted in severe mucosal damage 48 h after damage induction, which persisted for 7 days. Pre-treatment with either methimazole 0.04% or propylthiouracil 0.01% significantly decreased mucosal damage macroscopically (lesion area, lesion score and segmental weight) microscopically and also significantly decreased MPO level at both time points (P < 0.01). CONCLUSIONS: Methimazole and propylthiouracil significantly reduce mucosal damage and colonic weight in a rat model of colitis. The mode by which they do so remains to be studied.

Animals↗
PubMed1997

Effects of intravenous immunoglobulins on T-cell mediated, concanavalin A-induced hepatitis in mice.

Concanavalin A (ConA) activates T lymphocytes and causes T-cell mediated hepatic injury in mice. The intravenous administration of human immunoglobulins has beneficial effects in T-cell mediated diseases such as experimental autoimmune encephalomyelitis and adjuvant arthritis. In the present study, we examined the effects of intravenous immunoglobulins in a mouse model of T-cell mediated, acute liver injury induced by concanavalin A. Balb/c mice were inoculated with 12 mg/kg concanavalin A with or without intravenous immunoglobulins at doses of 0.4, 0.6, 0.8 g/kg body wt. The serum levels of liver enzymes, tumor necrosis factor-alpha, interferon-gamma and interleukin-6 were assayed 2, 6 and 24 h after concanavalin A administration. Intravenous immunoglobulins did not prevent concanavalin A-induced hepatitis, as manifested by elevation of serum aminotransferases and histopathological evaluation. The serum levels of tumor necrosis factor-alpha in mice pretreated with immunoglobulins, measured 2 h after ConA treatment were reduced, while interferon-gamma levels measured 6 h after ConA inoculation were 5-fold higher than control levels. There was no effect of intravenous immunoglobulins on the release of interleukin 6. In conclusion, these results indicate that intravenous immunoglobulin is not effective in preventing T-cell mediated concanavalin A-induced hepatitis. The increased secretion of interferon-gamma and the incomplete suppression of tumor necrosis factor-alpha release may explain the lack of efficacy of intravenous immunoglobulin in this experimental model.

Animals↗
PubMed1997

Analysis of Arg-Gly-Asp mimetics and soluble receptor of tumour necrosis factor as therapeutic modalities for concanavalin A induced hepatitis in mice.

BACKGROUND/AIMS: It has been shown that synthetic non-peptidic analogues of Arg-Gly-Asp, a major cell adhesive ligand of extracellular matrix, prevented an increase in serum aminotransferase activity, as a manifestation of concanavalin A induced liver damage in mice. This study examined the effects of an Arg-Gly-Asp mimetic on liver histology and cytokine release in response to concanavalin A administration, and the efficacy of soluble receptor of tumour necrosis factor (TNF) alpha in preventing hepatitis in this model of liver injury. METHODS: Mice were pretreated with either the Arg-Gly-Asp mimetic SF-6,5 or recombinant soluble receptor of TNF alpha before their inoculation with 10 mg/kg concanavalin A. Liver enzymes, histology, and the serum values of TNF alpha and interleukin (IL)6 were examined. RESULTS: The histopathological damage in the liver, and the concanavalin A induced release of TNF alpha and IL6 were significantly inhibited by the synthetic Arg-Gly-Asp mimetic (p < 0.001). Liver injury, manifested by the increase in serum aminotransferase and cytokines, as well as by histological manifestations of hepatic damage, was effectively prevented by pretreatment of the mice with the soluble TNF receptor (p < 0.001). CONCLUSIONS: This study confirms the efficacy of a synthetic Arg-Gly-Asp mimetic and soluble TNF receptor in the prevention of immune mediated liver damage in mice.

Alanine Transaminase↗
PubMed1997

Purpura fulminans induced by disseminated intravascular coagulation following infection in 2 unrelated children with double heterozygosity for factor V Leiden and protein S deficiency.

Purpura fulminans is associated with homozygous protein C and homozygous protein S deficiency or may follow bacterial or viral infections. We present 2 children from 2 unrelated Arab families with purpura fulminans who were double heterozygotes for factor V Leiden inherited from their fathers and protein S deficiency inherited from their mothers. No previous thrombotic events have occurred in either patient or their respective family members. In one patient sepsis accompanied by disseminated intravascular coagulation appeared to be the trigger of purpura fulminans. In the other patient varicella infection preceded purpura fulminans and was also associated with disseminated intravascular coagulation. This report emphasizes the need for evaluation of hereditary defects in the inhibitory mechanisms of blood coagulation in patients with purpura fulminans at any age.

Child, Preschool↗
PubMed1996

Vincristine treatment triggering the expression of asymptomatic Charcot-Marie-Tooth disease.

A 16-year-old male suffering from Ewing's sarcoma of the pelvis was treated with vincristine as part of his chemotherapeutic protocol. The boy was never known to suffer from any neurological problems. His father had a mild limp, attributed to prolonged "taxi driving," that was never investigated medically. The first course of treatment, which included 2 mg of vincristine, resulted in clinical improvement. However, at the same time the patient developed severe weakness of both upper and lower limbs, areflexia, and gradually a pes cavus deformity. Nerve conduction studies were suggestive of severe peripheral sensorimotor neuropathy, axonal and demyelinative. A definite diagnosis of Charcot-Marie-Tooth was confirmed by molecular analysis showing the typical duplication of 1.5 megabases at 17 p11.2. This unique manifestation of vincristine neurotoxicity is reported and discussed.

Adolescent↗
PubMed1995

Two embryonal cancers after in vitro fertilization.

BACKGROUND: In vitro fertilization is not considered to be associated with an increased rate of pediatric malignancies, and only three have been reported in the literature. Two additional rare pediatric tumors in children conceived through this technique are reported. METHODS: Two children 12 and 18 months of age, developed hepatoblastoma and clear cell sarcoma of the kidney, respectively. They were both products of uneventful pregnancies induced by in vitro fertilization. No other environmental, prenatal, or family factor was found. RESULTS: The first child died after a failed remission induction with cisplatin, doxorubicin, and vincristine, whereas the second child is alive with no evidence of disease 18 months after diagnosis and treatment according to NWTS protocol. CONCLUSIONS: A possible association between in vitro fertilization and pediatric malignancies is suggested.

Antibiotics, Antineoplastic↗
PubMed1995

Autologous umbilical cord blood transfusion.

The purpose of this study was to examine some aspects of umbilical cord blood collection for autologous transfusion in premature infants. All 120 microbacterial cultures (aerobic and anaerobic) of cord blood samples as well as 30 cultures of mycoplasma were treated. Cord prothrombin fragment (F 1 + 2) concentrations were quantified at one and 10 minutes after clamping of the cord. F 1 + 2 concentrations assessed on 25 newborn infants were similar and no linear association with time of clamping could be drawn. This means that cord blood thrombosis is not activated for at least 10 minutes following clamping of the cord. As far as is known, the first newborn infant to benefit from this method of transfusion is reported here. The premature infant received two portions of autologous blood (on days 5 and 7). No untoward effects were noted. Blood, collected from the umbilical cord, is a safe source for autotransfusion, provided that bacteriological testing has been carried out.

Blood Coagulation↗
PubMed1994

Familial clustering of malignant germ cell tumors and Langerhans' histiocytosis.

Three sisters in a family with seven children whose grandmother had an ovarian embryonal carcinoma experienced development of malignant and a malignant-like situation in childhood. Two were diagnosed as having malignant germ cell tumors of the ovary, and the third was found to have Langerhans' histiocytosis. The two girls with germ cell tumor shared an identical human leukocyte antigen, whereas the sister with histiocytosis shared one identical haplotype with them. All three children have been treated successfully with chemotherapy and are doing well off of treatment.

Aged↗
PubMed1994

Autologous cord blood transfusion.

Newborn piglets were exsanguinated (60% of blood volume) and retransfused 1 h later. One test group received adult pig red blood cells, the other piglet cord blood cells; controls were infused with plasma. While all controls died, satisfactory results were achieved in piglets transfused with either adult or foetal blood. The feasibility of collecting human cord blood for transfusion was assessed in 100 samples of human cord blood. Blood was collected aseptically and aerobic and anaerobic cultures set up. All samples of cord blood were sterile, and all were Mycoplasma negative. Coagulation parameters were analysed in eight cord plasma samples stored at -20 degrees C for 45 days. No significant abnormalities were found immediately after birth or after storage.

Animals↗
PubMed1994

Familial leukemia: description of two kindreds and a review of the genetic aspects of the disease.

We describe two kindreds of Arab ancestry characterized by multiple cases of acute lymphoblastic leukemia. Consanguinity and intermarriages were prevalent in the two families. Age, mode of presentation, characteristics of the leukemic cells, response to treatment and prognosis were remarkably similar among the patients. A short review of the literature on familial leukemia is given.

Child↗
PubMed1994

Lymphomatous T-cell leukemia in two Arab children. Is there a role for an environmental effect.

Two Arab children from the Gaza strip presented with fever, weakness, hepatosplenomegaly, lymphadenopathy and leukocytosis. The peripheral and bone marrow blasts had an immunophenotype compatable with T-cell acute lymphoblastic leukemia, and exhibited unusual markers (CD2+, CD3+, CD4-, CD8-). Cytogenetic studies revealed t(8;14)(q24;q11), possibly involving the alpha/delta locus of the T-cell receptor gene on chromosome 14 rather than the immunoglobulin heavy-chain locus usually involved in the t(8;14)(q24;q32), which is typical for Burkitt's leukemia/lymphoma. One of the children had a brother who died of T-cell acute lymphoblastic leukemia a few years later, however, his blasts showed deletion of chromosome 12. The possible role for environmental factors associated with low socioeconomic status, as well as of genetic factors in leukemogenesis are discussed.

Child, Preschool↗