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L Jaber

Publications and source records attributed to L Jaber.

14 recordsLinked to original sources
PubMed1992

Biochemical characterization of a pedigree with mitochondrially inherited deafness.

A large kindred with a predicted 2-locus inheritance of sensorineural deafness, caused by the combination of a mitochondrial and an autosomal recessive mutation, was examined at the biochemical level. Because of the mitochondrial inheritance of this disease, we looked for defects in the oxidative phosphorylation Complexes I, III, IV, and V, the 4 enzymes that include all of the 13 mitochondrially encoded polypeptides. Biosynthetic labelling of lymphoblastoid cells from deaf patients, unaffected siblings, and an unrelated control showed no difference in size, abundance, rate of synthesis, or chloramphenicol-sensitivity of the mitochondrially encoded subunits. Since overall mitochondrial protein synthesis appears normal, these results suggest that the mitochondrial mutation is unlikely to be in a tRNA or rRNA gene. No change in enzymatic levels was seen in lymphoblastoid mitochondria of the deaf patients, compared to unaffected sibs and controls, for Complexes I and IV. Both affected and unaffected family members showed an increase in Complex III activity compared to controls, which may reflect the mitochondrial DNA shared by maternal relatives, or be due to other genetic differences. Complex V activity was increased in deaf individuals compared to their unaffected sibs. Since the family members share the presumptive mitochondrial mutation, differences between deaf and unaffected individuals likely reflect the nuclear background and suggest that the autosomal recessive mutation may be related to the increase in Complex V activity. These biochemical studies provide a guide for sequence analysis of the patients' mitochondrial DNA and for linkage studies in this kindred.

Cell Line, Transformed↗
PubMed1992

Marked parental consanguinity as a cause for increased major malformations in an Israeli Arab community.

It is common among Israeli Arabs who live in the villages to prefer consanguineous marriages, particularly among first cousins. In addition, such villages are populated by a few (less than 20) original families, and inter-family/inter-village marriages are infrequent. The purpose of this study was to examine the consequences of such "consanguinity" in Taibe, a large Arab village, 30 km from Tel Aviv. Six hundred ten families were prospectively ascertained through infants who were routinely seen in the local "Well Baby Clinics." A significant increase in the incidence of major malformations was noted in relation to the closeness of the parental relationship. For the index cases group the prevalence of individuals with major malformations were 5.8% in the product of inter-village marriages, 8.3% in the intra-village non-related matings, 15.1% in the distant consanguineous group, and up to 15.8% in the progeny of first-cousin marriages (P less than 0.001). In the siblings of these index cases, the frequency of major malformations was 4.3%, 4.5%, 10.5%, and 10.3%, respectively. Analysis of the major malformations by each body system showed the same trend. The study demonstrates a marked high rate of consanguineous marriages, whose effect leads to a marked increase in major malformations and thus a prominent public health problem in such villages. This requires a unique genetic counseling approach.

Congenital Abnormalities↗
PubMed1992

T-cell acute lymphoblastic leukemia following therapy of rhabdomyosarcoma.

Multiple studies have documented an increased risk of secondary malignancies in patients receiving alkylating agents. Secondary leukemia following chemotherapy accounts for about 20% of all secondary neoplasms; most are acute nonlymphocytic. Secondary acute lymphoblastic leukemia has rarely been reported in either adult or childhood cancer. We report the development of acute T-cell lymphoblastic leukemia in a child following successful treatment of a paravertebral embryonal rhabdomyosarcoma (ERS). Southern blot analysis of DNA extracted from the T-cell lymphoblasts, using probes homologous to loci on the short arm of chromosome 11; P-calcitonin, P40.1 and H-ras, did not demonstrate the chromosomal loss of heterozygosity (LOH), a common feature of embryonal rhabdomyosarcoma. The data presented support the assumption that de novo leukemia emerged following treatment of the primary malignancy.

DNA, Neoplasm↗
PubMed1992

Reaction of the dental pulp to hydroxyapatite.

The purpose of this study was to evaluate the action of hydroxyapatite (HA) (Osteogen HA Resorb, GBD Marketing Group Inc., Valley Stream, N.Y.) on the dental pulp of rats. Four upper molar pulps in 45 rats were exposed and capped with synthetic HA (Osteogen) with a stereoscopic microscope. Pulps capped with calcium hydroxide (Dycal, L.D. Caulk Co., Milford, Del.) served as controls. The cavities were filled with amalgam, and the molars on each side of the maxilla were protected by the placement of a pedodontic steel crown. Pulp inflammation and dentin repair were compared by histologic observations and computer image analysis after 7, 14, and 28 days. After 7 days a partial acute pulpitis were observed in specimens treated with Osteogen or Dycal. Reparative dentin formation along the pulp walls was also seen. After 14 days the pulpitis was more extensive in the Osteogen-treated teeth than in the control teeth. Dentin formation as measured by morphometric analysis was more pronounced in Osteogen-treated teeth. Neo-odontoblasts were observed after the use of both materials. After 28 days an acute inflammatory reaction was still evident in the Osteogen-treated group. A complete dentinal bridge was observed more frequently with Dycal than with Osteogen. Despite the putative abilities of HA to be osteoconductive, osteogenic, and dentinogenic, the results of this study indicate that it should not be used as a pulp-capping agent because of its tendency to cause scattered dystrophic calcification in the dental pulp, which could interfere with future endodontic treatment.

Animals↗
PubMed1992

Fever associated with teething.

A relationship between teething and fever was sought by examining mothers' reports of the 20 days before the eruption of the first tooth in 46 healthy infants. Twenty infants had a fever of greater than 37.5 degrees C on day 0 compared with seven infants (or fewer) from day 19 to day 4. The danger of attributing fever to teething is emphasised.

Fever↗
PubMed1992

Sensorineural deafness inherited as a tissue specific mitochondrial disorder.

We present here a large Israeli-Arab kindred with hereditary deafness. In this family 55 deaf subjects (29M, 26F), who are otherwise healthy, have been identified and traced back five generations to one common female ancestor. The deafness is progressive in nature, usually presenting in infancy and childhood. Audiometry on six deaf and seven unaffected subjects was consistent with severe to profound sensorineural hearing loss. Based on formal family segregation analysis, the inheritance of deafness in this family closely fits the expectation of a two locus model owing to the simultaneous mutation of a mitochondrial gene and an autosomal recessive gene. Thus, this disorder appears to have the unusual features of being an inherited tissue specific mitochondrial disease and apparently requiring the homozygous presence of a nuclear gene for clinical expression. Most importantly, this disorder presents a unique opportunity to investigate the molecular basis of hereditary non-syndromic deafness and normal hearing.

Adult↗
PubMed1992

Prevalence of asthma in Israeli schoolchildren. A comparative study of Jewish and Arab populations.

The prevalence of asthma in 2,160 schoolchildren from Arab and Jewish rural and urban communities in central Israel, was determined by means of questionnaire. For the purposes of the study, asthmatic children were defined as those suffering from two or more asthmatic episodes which had been diagnosed by their physicians and had necessitated anti-asthmatic therapy. Doubtful cases were classified after personal interviewing and physical examination. The overall prevalence of asthma was 6.38%. In the Arab rural sample, it was 2.86%, significantly lower than the other groups studied: Arab urban 6.63% (P < 0.001), Jewish urban 9.2% and Jewish rural 8.66% (P < 0.001). The relatively low prevalence in the Arab rural sample is in accordance with the rarity of asthma reported from less advanced societies in other countries. The reasoning for the low asthmatic morbidity found in this group is not clear.

Asthma↗
PubMed1991

Electron microscope characteristics of dentin repair after hydroxylapatite direct pulp capping in rats.

In order to study the osteogenic action of hydroxylapatite (HA) on the dental pulp, a pulp capping experiment was designed using the rat upper molar. Under general anesthesia, molar teeth in 14 male Sprague-Dawley rats were pulp capped with Osteogen (HA) or with Dycal as a control material. After pulp capping, the maxillary molars cavities were restored with amalgam and a pedodontic steel crown was adjusted and sealed over the molar teeth on either side of the maxilla. After 7 days, the areas of necrosis and acute inflammation were more evident in the pulps treated with Dycal than with Osteogen. Hard tissue formation began to appear around dentinal chips in the pulp and extended from the cavity walls into the pulp regardless of the material that was used. Furthermore, this calcified material was scattered throughout the pulp when Osteogen was used, but was not observed in the Dycal treated pulps. The hard tissue formation was thought to be due to the putative fibroblasts and odontoblasts found in the pulp. After 28 days dense dentinal tissue was observed bridging the exposure site when Dycal was used. The dentinal tissues formed with Osteogen was always of a globular type, and showed an irregular distribution. Since Osteogen tends to cause areas of dystrophic calcification in the pulp, its use is not be recommended for pulp capping purposes in humans, because these areas of calcification would make future endodontic treatment difficult.

Animals↗
PubMed1990

[Israel national childhood acute lymphoblastic leukemia study].

A national childhood acute lymphoblastic leukemia (ALL) study was initiated in Israel in 1984 with the aim of improving results in difficult aspects of treatment including: high-risk groups, the problems of late relapses, and the effect of cranial irradiation for CNS prophylaxis in leading to late neuropsychiatric sequelae and secondary tumors. Induction of chemotherapy with a combination of 6 drugs (vincristine, cyclophosphamide, cytosine arabinoside, adriamycin, prednisone and L-asparaginase), followed by intensification with methotrexate and L-asparaginase, was introduced in both the usual and the high-risk groups. In a selected group with better prognostic factors, therapy was reduced. In an attempt to minimize the sequelae of CNS prophylactic therapy, cranial irradiation was omitted in half the patients and intrathecal (IT) triple therapy was given instead. Following 2 years of unsatisfactory preliminary results in a very high-risk group (VHR; non-T- and T-cell leukemia with WBC counts of greater than 100,000 and greater than 20,000, respectively), treatment was modified and intensified. Between Nov. 1984 and Feb. 1989, 143 patients were enrolled from 10 hospitals. During follow-up of a median of 2.5 years, there were 32 failures (2 failed remissions, 27 relapsed and 3 died of bleeding and sepsis). 107 patients are alive in first remission and an additional 8 in second and third remissions. By Kaplan-Meier life table analysis, the rates of leukemia-free interval (LFI) and event-free interval (EFI) for 4 years were 60% and 57%, respectively. Improved LFI results of 71% for 4 years were achieved in a group with non-T-cell ALL with WBC less than 100,000 (the largest group, 65% of the patients). In the small "good risk" group (10% of patients), and the T-cell group with WBC less than 100,000, LFI for 4 years were 56% and 54%, respectively. In the VHR group, modification seemed to have improved results: LFI of 41% for 3 years. CNS prophylaxis with IT triple therapy was as effective as cranial irradiation in the standard risk group. In 1 out of 33 children on this protocol a single CNS relapse occurred, as compared to 2 out of 35 matched controls with cranial irradiation. These results warrant extension of IT triple therapy to higher risk groups of childhood ALL. As for systemic treatment, increased up-front high-dose intensive therapy is recommended for all groups with ALL, but with reduction of cumulative dose to minimize late effects.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1976

Reconstitution of T cell function in patients with subacute sclerosing panencephalitis treated with thymus humoral factor.

Two patients with subacute sclerosing panencephalitis (SSPE) showed impairment of cell-mediated immunity, as indicated by a low T cell number, decreased intracellular cyclic AMP levels of peripheral blood lymphocytes, negative graft-vs.-host reaction in vivo, negative skin reactions to common antigens and, in one of the patients, abnormal reactions in migration inhibition factor tests. Since some of the impaired T cell functions in one of the patients were reconstituted in vitro by the administration of thymus humoral factor (THF), a thymic hormone shown in an earlier study to regulate maturation of T lymphocytes in in vitro and in vivo animal models, a course of THF administration was given to both patients in this study. In vitro and in vivo assays, which reflect T cell competence, were performed before and after a daily schedule of THF administration that lasted for 10 days in one patient and 21 days in the other. The results of this preliminary trial suggested that THF was capable of reconstituting the impaired T cell functions in both patients after a short term of treatment. These preliminary results should encourage additional long-term therapeutic trials with THF in SSPE patients with impaired cell-mediated immunity.

Animals↗
PubMedDate not supplied

Dactinomycin potentiation of radiation pneumonitis: a forgotten interaction.

No mention of dactinomycin potentiation of pulmonary radiation was found in a review of the literature of the past 12 years. Before that, this complication was well described and investigators had calculated that dactinomycin increased the toxic effect of lung radiation by a factor of 1.3 and reduced the radiation tolerance of the lung by at least 20%. An example of such a toxic effect is described in the treatment of a 7-year-old girl with lung metastases from Ewing's sarcoma. The chemotherapy protocol followed contained cyclophosphamide, vincristine, dactinomycin, adriamycin, cisplatinum, VP16, and radiotherapy. The treatment was associated with fatal pulmonary fibrosis following the reintroduction of dactinomycin after radiotherapy. Our experience suggests that there is clinical significance to this complication in sarcoma therapy when dactinomycin-containing protocols are used with radiation in the treatment of pulmonary metastases.

Animals↗
PubMedDate not supplied

Childhood malignant thymoma: clinical, therapeutic, and immunohistochemical considerations.

Malignant thymomas are among the least common mediastinal tumors in the pediatric age group. Thymomas are considered malignant on the basis of macroscopic and microscopic invasiveness. As only 20 well-documented cases involving children have been reported in the literature, the pattern of responsiveness to therapy and the value of prognostic signs is obscure. Two cases of malignant pediatric thymomas are reported with pathognomonic histoimmunological features of aggressive thymoma. One was cured, with a follow-up of 70 months, and one died while on therapy. Analysis of the histological features and the immunoperoxidase staining displays the complexity of pediatric thymomas and the inability to prognosticate the outcome, respectively.

Adolescent↗