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Biomedical subjects

M Mandel

Publications and source records attributed to M Mandel.

At least 55 records · Page 3Linked to original sources
PubMed1995

Relaxin gene expression in human reproductive tissues by in situ hybridization.

The expression of the two human relaxin genes termed H1 and H2 in human reproductive tissues ranges from high to very low copy number depending upon the tissue and reproductive state. The aim of this study was to use two approaches to identify total relaxin transcripts (HI and H2) at the cellular level by using a human relaxin H2 riboprobe and a series of six 48-mer synthetic oligoprobes. The results obtained with both methods were similar in all tissues studied; however, a lower background was achieved with the riboprobe. This was especially noticeable after long exposure times, and a better resolution was generally achieved without clustering of the signals. Treatment of the tissues with proteinase-K failed to increase the sensitivity in any tissue with either probe. The relative levels of expression of the total relaxin gene transcripts was estimated from the different exposure times needed to obtain a good hybridization signal. Thus, the order of expression was: corpus luteum of pregnancy > corpus luteum of the cycle > placenta and prostate > decidua parietalis. The results agree well with immunolocalization of the peptide hormone previously performed with both heterologous and homologous relaxin antibodies; the exception was the lack of hybridization signal over the cells of the chorionic cytotrophoblast of the chorion laeve. This suggests that the levels of relaxin gene expression was below the level of detectability with the in situ hybridization technique or that these cells sequester, but do not synthesize, relaxin. Expression in the term placenta varied greatly from tissue to tissue and within any one tissue. A similar variability has been noted for relaxin in this tissue by immunocytochemistry. Methodology for the detection of total relaxin transcripts at the cellular level when expressed in a wide range of copy number will allow the developmental regulation of relaxin gene expression in reproductive and nonreproductive tissues to be visualized.

Base Sequence↗
PubMed1994

Detection of small quantities of double stranded DNA by enhanced fluorescence of substituted aldehyde modified polydeoxynucleotide-ethidium bromide complexes.

A method for the detection of small amounts of double stranded DNA by a simple incubation procedure involving the reaction of the nucleotide bases in DNA with chloroacetaldehyde is described. Following incubation, the presence of DNA may be visualized by the orange fluorescence emitted when ethidium bromide (EtBr) is added. Alternatively, the aldehyde/DNA mixture may be separated by agarose gel electrophoresis and individual double stranded DNA visualized by exposing the gel to ethidium bromide and observing the orange ultraviolet light induced fluorescence of the aldehyde modified double stranded ethidium bromide complex (Waring, M.J. (1965) J. Mol. Biol. 13, 269-282). At least a 20-fold increase in the detection of double stranded DNA is possible by this procedure. An important aspect of this method is that the visualization of single stranded DNA is not enhanced.

Acetaldehyde↗
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

Physicochemical properties of aqueous xanthan solutions: static light scattering.

The secondary structure of xanthan in solutions of relatively low salt concentration and at room temperature has been investigated using static light scattering experiments. Additional evidence has been found for a dimeric structure at 25 degrees C in 0.01 M NaCl. From the experimental z-average mean square (ms) radius of gyration, a value for the persistence length p has been estimated, taking explicitly into account the polydispersity of the three samples used, which has been established by gel permeation chromatography (GPC) measurements. The experimental particle scattering functions of the three samples are consistent with theoretical estimates for polydisperse systems with the same value of p = 65 +/- 10 nm and the molar mass per unit length for a dimeric structure. This secondary structure remains unaffected by the ionic strength in the 0.005-0.01 M range. Partial aggregation seems to occur at higher NaCl concentrations. Light scattering and GPC data show that heating the xanthan 0.01 M NaCl solutions to about 70 degrees C considerably reduces the Mw of the low molar mass sample (2.3 x 10(5) g.mol-1), contrary to what is observed for the high molar mass sample (1.8 x 10(6) g.mol-1). These experimental findings can be accounted for by a partial temperature-induced dissociation of the xanthan dimers according to an all-or-none mechanism.

Carbohydrate Conformation↗
PubMed1994

CD10+ cell population in the bone marrow of patients with advanced neuroblastoma.

Immunocytologic analyses of bone marrow can provide clinically useful prognostic information in neuroblastoma. While analyzing the bone marrow with a panel of monoclonal antibodies, which detect neuroblasts and other defining B-, T-, and myloid lineage, we identified two infants with stage IV-S neuroblastoma whose bone marrow contained a large population of common acute lymphoblastic leukemia (ALL)-like cells. This population expressed HLA-DR, CD19(B1), CD10(CALLA), and occasionally CD20(B1). Since 1988, 17 additional patients with advanced neuroblastoma (IV-S, III, and IV) were studied by us. In 10 of the 19 patients, the bone marrow revealed an expanded CD10 population (20-70%). It appears that this group of patients has a better prognosis. Out of 9 patients who did not have an expanded CD10 population, 8 died within 9 months from diagnosis, whereas out of 10 patients with an expanded CD10 population only one died and the others are alive, 6-30 months from diagnosis (P < 0.001). An expanded CD10 population in the bone marrow of disseminated neuroblastoma patients may therefore serve as a prognostic factor. Apart from the prognostic value of this particular population in the single patient, its presence may shed light on the interrelationship between the immune system and the neuroendocrine compartment.

Adolescent↗
PubMed1994

Hormonal treatment in pregnancy: a possible risk factor for neuroblastoma.

In the last 4 years, 24 cases of neuroblastoma were treated in the Pediatric Hematology-Oncology Unit at the Chaim Sheba Medical Center, 8 of whom were under 1 year of age. Four of them were the product of a pregnancy-induced or preserved by gonadotropins, clomiphene citrate, or progestational hormones. These drugs are known to produce a higher than normal level of estradiol or progesterone in the early stages of pregnancy. Our observation led to the hypothesis that high levels of progestational hormones given during pregnancy are a risk factor for neuroblastoma in infancy.

20-alpha-Dihydroprogesterone↗
PubMed1994

Primary central nervous system Burkitt's lymphoma presenting as Guillain-Barré syndrome.

A rare case of CNS Burkitt's lymphoma presenting as acute Guillain-Barré syndrome is presented. A 6-year-old previously healthy female presented with acute onset of limb and truncal weakness, involvement of ocular and bulbar nerves, and areflexia. The clinical diagnosis of Guillain-Barré syndrome prompted treatment with intravenous gammaglobulin with no response. A lumbar puncture following revealed marked pleocytosis, elevated protein, and decreased glucose. Immunological, cytological, and molecular studies of these cells confirmed the diagnosis of Burkitt's lymphoma IgM, kappa with t(8;14) and rearrangement of the J and kappa immunoglobulin chains. Aggressive systemic and intrathecal chemotherapy were started and within 5 days remission was achieved. The child is in complete remission 2 years from diagnosis. Although very rare, CNS lymphoma should be taken into account in every patient presenting with the clinical features of acute polyneuropathy.

Acute Disease↗
PubMed1994

Ependymoblastoma in an HIV-positive hemophilic girl.

A case of an HIV-positive hemophilic girl with an ependymoblastoma is presented. The unusual association between the HIV-related condition and her brain tumor is discussed, speculating a viral mechanism involved in the induction of neoplasia.

Adolescent↗
PubMed1994

Congenital haemolytic anaemia associated with adenylate kinase deficiency.

Chronic haemolytic anaemia associated with adenylate kinase (AK) deficiency is very rare and only seven cases in five families have been described. We present six children of one family who are deficient of this enzyme and in three of them a combined G6PD deficiency was found. AK deficiency was transmitted by an autosomal recessive gene and heterozygous state was not accompanied by disease, whereas homozygously affected individuals present a congenital chronic non-spherocytic haemolytic anaemia with haemoglobin levels of 8-9 g/dl. Patients also deficient in G6PD suffer from a more severe haemolytic anaemia with haemoglobin levels around 6 g/dl. The AK-deficient children are also mentally retarded. Splenectomy performed in five of the six patients resulted in complete remission of the haemolytic process.

Adenylate Kinase↗
PubMed1994

A point mutation in the human serum albumin gene results in familial dysalbuminaemic hyperthyroxinaemia.

Using DNA samples obtained from two unrelated patients, diagnosed as having familial dysalbuminaemic hyperthyroxinaemia (FDH), exons 1-14 which span the entire coding region of the human serum albumin (HSA) gene were amplified by the polymerase chain reaction. The sequence of each of the 14 DNA fragments was then determined. In each case a point mutation was identified at nucleotide 653 which causes an Arg to His substitution at amino acid position 218. The substitution was confirmed by amino acid sequencing of a mutant peptide resulting from tryptic digestion of the protein. Abnormal affinity of FDH HSA for a thyroxine (T4) analogue was verified by an adaptation of the procedure used in routine free T4 measurement. The location of the mutation is discussed in relation to other studies on the binding properties of HSA.

Amino Acid Sequence↗
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↗
PubMed1994

In vivo clonal evolution of pre-B to B-cell acute lymphoblastic leukemia in childhood.

Two cases are described that provide further evidence for clonal evolution in pre-B-cell acute lymphoblastic leukemia. Two infants, whose lymphoblasts at diagnosis were morphologically subtyped as L1 and immunophenotyped as HLA DR+, CD19+, CD10+/- and C mu-, were induced and maintained in remission. One child relapsed 6 months after initiation of therapy. This time his lymphoblasts had L3 morphology and immunophenotyping demonstrated the appearance of surface immunoglobulins. The second child relapsed 18 months after initiation of therapy with a lymphomatous picture. He also had peripheral and bone marrow blasts with L3 morphology and surface immunoglobulins. A lymph node biopsy showed diffuse small non-cleaved lymphoma with a 'starry sky' appearance compatible with Burkitt's lymphoma. Only one case with a similar clonal evolution has been reported in the literature, but no surface immunoglobulins were demonstrated. The significance of clonal evolution in these cases and its potential practical implications are discussed.

Clone Cells↗
PubMed1993

Favorable response of pediatric AIDS-related Burkitt's lymphoma treated by aggressive chemotherapy.

We describe 4 male children infected by the human immunodeficiency virus (HIV) who developed Burkitt's lymphoma during their disease. The clinical picture was characterized by an insidious appearance of symptoms. All the children suffered for several months from abdominal discomfort and a gradual elevation of their blood lactic dehydrogenase (LDH) level prior to diagnosis. Bone marrow involvement was found in 2 of the patients and jaw involvement in the other 2. After confirming the diagnosis of Burkitt's lymphoma, they were treated according to conventional protocols, with no need to reduce the dose intensity. They all went into complete remission and did not suffer from major opportunistic infections during chemotherapy. None of them relapsed. Two patients died from opportunistic infections 1 and 3 years after diagnosis. The other 2 are alive, 7 years and 6 months after diagnosis. The various characteristics of this unique pediatric group are described and the comparison of the clinical picture in adults is made, together with a review of the relevant literature.

Adolescent↗