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Biomedical subjects

H Isaacs

Publications and source records attributed to H Isaacs.

At least 37 records · Page 2Linked to original sources
PubMed1991

Centronuclear myopathy--an inherited neuromuscular disorder. A report of 3 cases.

Three patients with the adult form of centronuclear myopathy are presented. The slow progression of this disorder is confirmed. The investigations included muscle and sural nerve biopsies. The electron microscopic findings in the muscle of these patients are unique, as are the results of histological examination and histochemical tests. The sural nerve studies were within normal limits. Insulin estimations in response to glucose loading were normal, which largely negates the possibility of an insulin-receptor defect in this disorder.

Adult↗
PubMed1991

Kinase activity and protein phosphorylation in control and malignant hyperthermic skeletal muscle.

1. Native 6% Laemmli gels were used to resolve 7 protein kinase activity bands in control and malignant hyperthermia (MH)-susceptible porcine and human skeletal muscle extracts. 2. MH-susceptible samples were consistently more active than the controls. 3. Following halothane treatment, a 43 kDa component displayed increased phosphorylation by a calcium-calmodulin dependent kinase in MH-susceptible vs control human samples. 4. Increased phosphorylation of additional endogenous protein components of molecular mass 116 and 60 kDa was observed.

Animals↗
PubMed1991

Pulmonary blastoma: a rare childhood malignancy.

Pulmonary blastoma is a rare primary malignancy of the lung, with few cases reported in children. The tumor consists of mesenchymal and epithelial components resembling the fetal lung. Seven children (aged 18 months to 5 years) with pulmonary blastoma were studied. The pulmonary radiographic patterns seen were a large, space-occupying solid mass with opacification of the hemithorax and preexisting cystic disease with a small solid tumor component. Computed tomographic images showed a low-attenuation mass with whorls of high-attenuation solid tissue. Four of the seven patients died within 2 years despite surgery and therapy; of the three surviving patients, one has recurrent disease.

Child, Preschool↗
PubMed1991

Results of treatment of malignant germ cell tumors in 93 children: a report from the Childrens Cancer Study Group.

We report treatment results in 93 children entered on study from 1978 to 1984 with malignant germ cell tumors (MGCTs), excluding dysgerminoma and tumors of the testis or brain. The estimated 4-year survival and event-free survival (EFS) for all 93 patients were 54% and 49%, respectively. For 30 children with ovarian tumors, the estimated 4-year survival was 67% and EFS was 63%. For 63 children with nongonadal tumors, survival and EFS were 48% and 42%, respectively. The comparison of EFS between ovarian and nongonadal tumors was significant at P = .03. The treatment plan included a second-look surgical procedure after 18 weeks of chemotherapy. Over half of 36 patients evaluated as having a residual mass present immediately before second-look surgery had no malignant tumor after review of surgical specimens. Age greater than 11 years at diagnosis, incomplete removal of tumor at first surgery, and more than one structure or organ involved at diagnosis increased the risk for adverse event. The histologic subtype of the primary tumor was not related to outcome. Diagnosis was verified by independent pathologic review, and treatment was uniform. Seventeen percent of all registered patients (21 of 127) were excluded because of ineligible pathologic diagnoses; sixty percent (13 of 21) were immature teratomas.

Adolescent↗
PubMed1990

An association between certain congenital abnormalities and the malignant hyperthermia trait.

Although an association between malignant hyperthermia (MH) and congenital abnormalities has been recorded, no prospective study has been attempted to investigate this relationship. Standardised in vitro muscle tests were performed, because of impending anaesthesia for corrective surgery, on 25 children with birth defects similar to those induced by hyperthermia in laboratory animals, and in whom excessive pyrexial reactivity to anaesthesia, drugs or stress were recorded. Fifteen of the 25 children were MH positive by responding abnormally to the administration of halothane/caffeine. Five of these patients reacted positively to both caffeine and halothane, while the remainder manifested a contractile response to halothane only. This study underlines the existence of an anaesthetic risk factor associated with certain congenital abnormalities and neurodevelopmental delay and emphasises the need for further research to elucidate the possible importance of heat stress during fetal development in genetically susceptible individuals.

Adolescent↗
PubMed1990

Mesenchymal hamartoma of the liver. A 35-year review.

Mesenchymal hamartoma of the liver occurs almost exclusively in infancy and childhood, with approximately 140 total cases reported. We report the experience with 18 patients at the Childrens Hospital of Los Angeles (Calif) during the past 35 years. The charts of all patients with mesenchymal hamartoma were retrospectively reviewed. The mean age at presentation was 16 months. Thirteen patients were symptomatic, presenting with increasing abdominal distention. Physical examination revealed an abdominal mass or hepatomegaly. Ultrasonography and computed tomography were the most useful diagnostic tests. Fourteen patients underwent resection; 9 underwent hepatic resection and 5 underwent excision of the tumor only. One patient had marsupialization, 1 underwent a biopsy only, and 2 died of unrelated causes and the hamartoma was found incidentally at autopsy. In all instances, a large cystic mass with well-demarcated margins was found. Three patients were unavailable for follow-up and 13 patients were alive and well 1 month to 24 years (mean, 5 years) after diagnosis. Recurrence or malignant transformation was not noted. A presumptive diagnosis can be made preoperatively by normal laboratory values and a combination of ultrasonography and computed tomography. We recommend excision of the tumor in all patients once the diagnosis is made, with the expectation of complete recovery.

California↗
PubMed1990

Role of chemotherapy in pediatric pulmonary blastoma.

Pulmonary blastoma is a rare malignant tumor of the lung that has been treated primarily with surgery. The effect of combination chemotherapy has not been systematically investigated. Two pediatric cases are reported in whom combination chemotherapy consisting of vincristine, actinomycin-D, cyclophosphamide, cis-platinum, and adriamycin was successfully used. The first case, a 5-year-old boy, underwent incomplete surgical excision of the tumor followed by a 104-week course of combination chemotherapy. The second case is a 3-year-old boy who was initially treated with combination chemotherapy that resulted in an objective response; he subsequently underwent surgical excision. This intensive combination chemotherapy is effective both in inoperable tumors as initial therapy as well as a surgical adjuvant.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Concurrence of malignant hyperthermia and congenital abnormalities.

Two children about to undergo corrective surgery were required to be investigated for malignant hyperthermia (MH). These investigations arose out of concern by the anesthetist who had obtained a history of unexplained pyrexial reactions to anaesthetic in other members of the family. Because over the years we have encountered several children with multiple congenital abnormalities who have been found to be susceptible to MH, we stressed the advisability of biopsying not only the patient but also the patient's parents. Positive responses for MH were obtained in the patients and in one of the parents on each occasion. The hypothesis of intrauterine MH with its pharmacogenetic propensity for heat production is considered as a possible etiological factor which may cause abnormalities of a congenital nature.

Child↗
PubMed1989

Distal dystrophy--unusual presentations. A report of 2 cases.

Two men suffering from progressive muscle wasting and weakness are described. The first patient presented with a rapidly progressive myopathy of the right lower leg characterised on histological examination of muscle biopsy specimens by extensive ringed fibre formation. The second patient exhibited severe muscle weakness and wasting of the lower legs characterised by the accumulation of amorphous sarcoplasmic material and vacuolation seen on histochemical evaluation and confirmed by electron microscopy. There was no clinical or electrophysiological evidence of myotonia in either case.

Adult↗
PubMed1989

Myophosphorylase B deficiency and malignant hyperthermia.

A 6-year-old boy was examined with the dual purpose of establishing whether he had malignant hyperthermia (MH) and to investigate his complaint of excessive muscle fatiguability. In the course of such investigations, McArdle's disease was diagnosed, and the patient was also identified as an MH-positive reactor.

Child↗
PubMed1989

Does heat damage fetuses?

Temperature affects phenotypic variation during critical developmental stages in all forms of life that have been studied thus far. In animal studies of heat teratogenicity, adverse effects have ranged from disruption of the normal cell cycle leading to decreased numbers of cells, to the induction of developmental abnormalities by means of embryonic cell death. The heat shock response is a universal cellular stress reaction in which the transcriptional and translational mechanisms of the cell are pre-empted by preferential induction of heat shock protein synthesis. Occurrence of such a phenomenon during prenatal life could lead to the absence of essential gene products at critical stages of development. The crucial question of whether temperature induced cellular and genetic effects ever occur during human fetal development has been considered only in relation to maternal hyperthermia, which is generally viewed as not being of significance in human teratology. We propose that teratogenicity may result from fetal hyperthermia unrelated to maternal hyperthermia, caused either by impaired fetomaternal heat dissipation due to reduced placental blood flow (extrinsic fetal hyperthermia) or by increased fetal heat production during hypermetabolic states (intrinsic fetal hyperthermia). The need for further studies in this regard is emphasized.

Animals↗
PubMed1989

Lymphomatoid granulomatosis in a 13-month-old infant.

Lymphomatoid granulomatosis is an infrequent, progressive, and frequently fatal vasculitis which typically occurs in middle aged males. We describe a 13-month-old infant with lymphomatoid granulomatosis who presented with chronic otitis media and "failure to thrive." Although it is well recognized that rheumatic conditions may result in failure to thrive, pediatricians often fail to consider this possibility and the proper diagnosis and treatment are correspondingly delayed. Lymphomatoid granulomatosis occurs with increased frequency in immunocompromised patients. In our case both hypogammaglobulinemia and persistent evidence of Epstein-Barr virus infection suggest that the infant was immunocompromised. Whether these factors predisposed this infant to lymphomatoid granulomatosis is uncertain. No patient with the onset of lymphomatoid granulomatosis prior to 7 years of age has been reported.

Agammaglobulinemia↗
PubMed1988

Comparative evaluation of the bone marrow by the volumetric method, particle smears, and biopsies in pediatric disorders.

Bone marrow cellularity estimated by biopsy was compared to the cellularity of the aspirate particle smear and the volumetric method in two groups of children. In the first group, 101 consecutive bone marrow biopsies and aspirates were evaluated from patients with various diagnoses. In the second group, 20 patients with acute nonlymphoblastic leukemia were studied with 80 biopsies and aspirates at diagnosis and following chemotherapy. A wide discrepancy was noted between bone marrow cellularity confirmed by biopsy vs. the particle smear or the volumetric method in both groups. Neither the volumetric nor the particle method provides a good correlation of bone marrow cellularity. We also compared the volumetric method with that of the biopsy to evaluate the efficacy of the former method in detecting bone marrow infiltration by solid tumors. The volumetric method is an accurate modality of identifying solid tumor infiltration in the bone marrow.

Biopsy↗
PubMed1988

Duplication of the hepatopancreatic bud presenting as pyloric stenosis.

Duplication of systemic organs is not a frequent finding. We report the occurrence of duplication of the hepatopancreatic bud with presence of mature hepatic and pancreatic tissue in a nine-day-old girl who presented with intestinal obstruction mimicking infantile hypertrophic pyloric stenosis.

Diagnosis, Differential↗