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Biomedical subjects

L Mak

Publications and source records attributed to L Mak.

10 recordsLinked to original sources
PubMed2001

Segmental amplification of 11q23 region identified by fluorescence in situ hybridization in four patients with myeloid disorders: a review.

Four cases with a segmental amplification of 11q23 region were detected by FISH. The amplification was either contiguous amplification on chromosome 11, or multiple markers involving the 11q23 region. The markers were derivative chromosomes, or isochromosomes. Amplification of 11q23 region was associated with complex karyotypes at the time of diagnosis or following treatment in secondary leukemias. Three were AML cases belonging to either AML-M5a or AML-1 subtypes and one was a myeloproliferative disorder. These cases were resistant to treatment. Conventional cytogenetic analysis and fluorescence in situ hybridization (FISH) studies using MLL, 11 painting, or 11 centromere probes ascertained the segmental amplification. Since the patients did not respond to treatment the amplification of gene or genes that map to 11q23 may be responsible for the unfavorable prognosis. Hence, this type of amplifications could have clinical significance.

Acute Disease↗
PubMed2001

An hsr on chromosome 7 was shown to be an insertion of four copies of the 11q23 MLL gene region in an HIV-related lymphoma.

A 45-year-old male with AIDS presented with a cecal diffuse large B-cell lymphoma. Cytogenetic and flourescence in situ hybridization (FISH) studies revealed a complex karyotype with multiple aberrations that included a translocation, t(8;14) involving MYC on chromosome 14. This is specific to B-cell lymphomas. There were also frequently observed secondary changes such as chromosome 1 rearrangement leading to trisomy of 1q and loss of tp53 from the deleted chromosome 17. A unique secondary abnormality was an hsr on chromosome 7, which by FISH and SKY investigations was shown to originate from chromosome 11 involving 4 copies of the MLL gene region.

Cecal Neoplasms↗
PubMed2000

FISH analysis of an AML-M5a with segmental rearrangements involving 11q23-MLL region.

A 66-year-old man was diagnosed 10 years ago with thrombocytosis and treated with hydroxyurea. Recently, his condition deteriorated and he was found to have 68% blasts in the blood and AML-M5a. Conventional cytogenetic analysis and fluorescence in situ hybridization studies using 11-painting and MLL probes showed that chromosome 11 had duplications or triplications; the markers were also derived from the chromosome 11-MLL region. Therefore, we have demonstrated segmental rearrangement of chromosome 11 involving the MLL region resulting in multiple copies of the MLL gene.

Aged↗
PubMed2000

A child with ALL and ETV6/AML1 fusion on a chromosome 12 due to an insertion of AML1 and loss of ETV6 from the homolog involved in a t(12;15)(p13;q15).

A 4-year-old boy was found to have acute lymphoblastic leukemia characterized by a t(12;15)(p13;q15). FISH investigation using a TEL(ETV6)/AML1 probe detected a fusion signal in 98% of the interphase cells. Sequential FISH on a G-banded slide showed a fusion signal on an apparently normal chromosome 12 and AML1 signals on chromosomes 21. The ETV6 was deleted from the chromosome 12 involved in the t(12;15). These results are best explained as an insertion of AML1 into TEL on one chromosome arm 12p and loss of ETV6 from the chromosome 12 involved in the t(12;15).

Child, Preschool↗
PubMed1999

Dual effect of spermine on mast cell secretion exhibits different calcium and temperature requirements.

Mast cells release many biologically active molecules upon stimulation by a variety of molecules such as immunoglobulin E (IgE) and specific antigen, anaphylatoxins, as well as a number of cationic compounds which include drugs, kinins and neuropeptides. The effect of the naturally occurring polyamine spermine was studied because, even though it is polycationic, it has been implicated in the modulation of secretory processes in a variety of cells. In particular, it was previously shown that oxidation products of spermine inhibit mast cell secretion. High concentrations of spermine (5 x 10(-3) M) added at 37 degrees C induced mast cell secretion that had similar characteristics with that triggered by compound 48/80 (48/80). However, spermine inhibited mast cell secretion in a dose-dependent manner as long as it was added at 4-10 degrees C for at least 10 min in the absence of Ca++ before warming the cells to 37 degrees C and triggering them with 48/80. These findings were true both for purified rat peritoneal mast cells and for rat skin mast cells in situ. Addition of calcium after the cells had been warmed to 37 degrees C could not reverse this inhibition. The inhibition seen when spermine was added at 4 degrees C was, however, overcome if phorbol myristate acetate (PMA) or NaF, which activate PKC and G proteins respectively, were added to mast cells at 37 degrees C together with Ca++. These results indicate that polyamines could be important modulators of the activation state of mast cells and might help further define the biochemical events involved in mast cell secretion.

Animals↗
PubMed1986

Acidic and basic hair/nail ("hard") keratins: their colocalization in upper cortical and cuticle cells of the human hair follicle and their relationship to "soft" keratins.

Although numerous hair proteins have been studied biochemically and many have been sequenced, relatively little is known about their in situ distribution and differential expression in the hair follicle. To study this problem, we have prepared several mouse monoclonal antibodies that recognize different classes of human hair proteins. Our AE14 antibody recognizes a group of 10-25K hair proteins which most likely corresponds to the high sulfur proteins, our AE12 and AE13 antibodies define a doublet of 44K/46K proteins which are relatively acidic and correspond to the type I low sulfur keratins, and our previously described AE3 antibody recognizes a triplet of 56K/59K/60K proteins which are relatively basic and correspond to the type II low sulfur keratins. Using these and other immunological probes, we demonstrate the following. The acidic 44K/46K and basic 56-60K hair keratins appear coordinately in upper corticle and cuticle cells. The 10-25K, AE14-reactive antigens are expressed only later in more matured corticle cells that are in the upper elongation zone, but these antigens are absent from cuticle cells. The 10-nm filaments of the inner root sheath cells fail to react with any of our monoclonal antibodies and are therefore immunologically distinguishable from the cortex and cuticle filaments. Nail plate contains 10-20% soft keratins in addition to large amounts of hair keratins; these soft keratins have been identified as the 50K/58K and 48K/56K keratin pairs. Taken together, these results suggest that the precursor cells of hair cortex and nail plate share a major pathway of epithelial differentiation, and that the acidic 44K/46K and basic 56-60K hard keratins represent a co-expressed keratin pair which can serve as a marker for hair/nail-type epithelial differentiation.

Antibodies, Monoclonal↗
PubMed1983

Sclerosing stromal tumor of the ovary: case report and review of the literature.

A case of sclerosing stromal tumor of the ovary in a Chinese girl of 17 years is reported. She presented with metrorrhagia and an abdominal mass in the right lower quadrant. At operation, a large unilocular cyst was found in the right ovary. Light microscopic and ultrastructural study established the diagnosis of sclerosing stromal tumor of the ovary. To date, 63 cases have been recorded in the literature, 33 of which have been described in detail.

Adolescent↗
PubMed1977

[A new diet for inducing early experimental atherosclerosis in rabbits].

Authors by a new combined diet consisting of cholesterol vitamin D3 and sour cream produced clinico-biochemical changes characteristic for atherosclerosis in a very short period in rabbits. This diet caused severe lipoproteinaemia, hypercholesterinaemia and microscopis and macroscopic changes in the aortic wall. Authors assume, that this diet is suitable for producin atherosclerosis in a short period.

Animals↗
PubMedDate not supplied

Mosaic unbalanced structural abnormalities confirmed using FISH on buccal mucosal cells.

Three rare mosaic unbalanced structural rearrangements found in routine peripheral blood analysis were confirmed in buccal mucosal cells using interphase FISH. Case 1 had a de novo mosaic triplication for 13q22q33 found in 22.5 % lymphocytes. D13S585 probe that maps to 13q32q33 confirmed the mosaicism in 41 % of buccal mucosal cells. Case 2 had additional material on a 3q derived from 14q31qter in 83 % of lymphocytes. The 14q-subtelomeric probe was used on buccal smear cells: 86 % had three signals and 14 % had two signals. Case 3 was a mosaic de novo add(5) in 32 % lymphocytes. The additional material was from 3p26pter. The 3p-subtelomere probe confirmed the mosaicism in 40 % buccal epithelial cells. This study shows the applicability of interphase FISH to confirm mosaic unbalanced rearrangements in a second tissue such as buccal mucosal cells.

Abnormalities, Multiple↗