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Biomedical subjects

M N Ahmed

Publications and source records attributed to M N Ahmed.

At least 19 recordsLinked to original sources
PubMed2001

Breast cancer: incidence, mortality, and early detection in Louisiana, 1988-1997.

Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer death among Louisiana women. The incidence data from Louisiana Tumor Registry were used to calculate breast cancer incidence rates, which were compared with the combined rates from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program. Breast cancer mortality rates for Louisiana were compared with the US death rates from the National Center for Health Statistics (NCHS). Our data revealed that Louisiana women were not at a higher risk for developing breast cancer than women in the SEER areas, but that mortality rates in Louisiana were not correspondingly low. Although the percentage of cases diagnosed at an early stage (in situ and localized) increased in Louisiana from 1988 through 1997, the average in Louisiana was still below the level for the SEER areas (65.9% and 71.6%) in 1993-1997. The rates of in situ breast cancer significantly increased (on average 5.3% for whites per year and 7.1% for blacks), and localized breast cancer also significantly increased (2.6% for whites and 2.5% for blacks), while the incidence of distant stage breast cancer significantly decreased (3.4% for whites and 2.0% for blacks). Compared with white women, black women still were less likely to be diagnosed with early stage breast cancer in 1993-1997 (56.4% and 68.9%). Women residing in the parishes with high percentages of persons in poverty were less likely to be diagnosed with early stage of disease.

Black People↗
PubMed2000

Comparative genomic hybridization studies in hydatidiform moles and choriocarcinoma: amplification of 7q21-q31 and loss of 8p12-p21 in choriocarcinoma.

Comparative genomic hybridization (CGH) was utilized to investigate genetic changes from archived cases of choriocarcinoma (n = 12) and hydatidiform moles (n = 7). Test DNA was extracted from paraffin-embedded tissues, amplified using total universal PCR, and co-hybridized with control DNA to normal metaphases. Comparative genomic hybridization findings showed chromosomal imbalances in 9 of 12 cases of choriocarcinoma. By contrast, all hydatidiform moles showed normal CGH profiles. Consistent findings in choriocarcinoma included deletion at 8p (5 cases) and amplification at 7q (4 cases). A tumor suppressor gene (e.g., N33) at 8p and/or a growth regulator at 7q could play a role in the initiation of choriocarcinoma and its progression. This is the first study showing specific alterations in choriocarcinomas by CGH, and illustrates the utility of this technique in elucidating genetic changes in gynecological tumors.

Adult↗
PubMed2000

Cytogenetics and mechanisms of spontaneous abortions: increased apoptosis and decreased cell proliferation in chromosomally abnormal villi.

Genetic defects of the zygote, such as chromosome aberrations, are the most frequent causes of abnormal embryonic development and spontaneous abortion. However, the underlying mechanisms remain unknown. Chromosome aberrations likely cause changes in placental morphology and function (such as size, shape, vascularity, and the presence of trophoblastic inclusion). We postulated that chromosome aberrations may affect rates of cell proliferation or programmed cell death (apoptosis) during the differentiation of chorionic villi. To address these questions, we evaluated cell proliferation using a monoclonal antibody to Ki-67 (a cell-cycle marker) and apoptosis using the in situ end-labeling method (TUNEL) on paraffin-embedded placental tissues. Tissues were obtained from spontaneous abortions in early gestational periods with normal (11 cases) and abnormal karyotypes (15 cases), as well as eight normal control placentas from elective abortions. Apoptotic cells were found in the stroma of all cases, but were significantly higher in number in the stroma of chromosomally abnormal versus chromosomally normal spontaneous abortions. The apoptotic index of the trophoblasts was not significantly different between groups. Cell proliferation was higher in muscularized blood vessels in chromosomally normal placentas (both elective and spontaneous abortions) versus chromosomally abnormal spontaneous abortions. Cell proliferation was different in the trophoblast and stroma between the groups but to a lesser degree than in blood vessels. The morphological and biological data presented here suggest that: (1) chromosomally abnormal spontaneous abortions may occur because of different mechanisms than chromosomally normal spontaneous abortions, (2) apoptosis of the stromal cells and cell proliferation in blood vessels and stroma play an important role in the differentiation and functioning of villi, and (3) these changes could explain the etiology of spontaneous abortion and growth retardation of chromosomally abnormal embryos.

Abortion, Induced↗
PubMed2000

Induction of DNA replication in adult rat neurons by deregulation of the retinoblastoma/E2F G1 cell cycle pathway.

In adult organisms, a range of proliferative capacities are exhibited by different cell types. Stem cell populations in many tissues readily enter the cell cycle when presented with serum growth factors or other proliferative cues, whereas "terminally" postmitotic cells, such as cardiac myocytes and neurons, fail to do so. Although they rarely show evidence of a proliferative capacity in vivo, there is accumulating evidence to suggest that DNA synthesis can be triggered in postmitotic cells. We now show that cultured adult rat sensory neurons can replicate DNA in response to ectopic expression of E2F1 or E2F2 and that this is augmented by expression of cyclin-dependent kinase activities. We also find that addition of serum and laminin inhibits the E2F-induced S-phase in neurons but not in nonneuronal cells in the same cultures. We conclude that, although terminally differentiated neurons possess the capacity to reinitiate DNA replication in response to G1 regulatory activities, they fail to do so in the presence of signals that do not inhibit S-phase in other cell types in the same cultures. This suggests the existence of cell type-specific inhibitory pathways induced by these signals.

Adenoviridae↗
PubMed1999

Cancer of the colon and rectum in Louisiana.

Cancer of the colon and rectum ranks fourth for incidence and second for mortality among Louisiana residents. Incidence rates calculated from Louisiana Tumor Registry data for 1991-95 show that whites in Louisiana were diagnosed with colon cancer at approximately the same rates as those in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, but rates for African Americans were significantly lower in Louisiana than nationally. For rectal cancer, Louisiana incidence rates approximate the national rates for all but African-American males, whose rate was significantly lower. Mortality rates for colon and rectal cancer in Louisiana were comparable to the SEER rates, suggesting Louisiana blacks, once diagnosed, have a poorer survival than their national counterparts. Risk factors for colorectal cancer and guidelines for screening are discussed, as is an upcoming study of patient care for colon cancer.

Adult↗
PubMed1999

Louisiana Tumor Registry: new developments and activities.

New developments in the Louisiana Tumor Registry (LTR) over the past 3 years have enhanced the operation of the LTR and broadened its functions. Recent funding for numerous special studies and research collaborations have expanded the registry activities from data collection and special etiologic studies to more completely address the mandates of registry law, which require the LTR to participate in studies of cancer causes, treatment, and survival in order to reduce cancer morbidity and mortality in Louisiana.

Humans↗
PubMed1998

Familial subepithelial corneal amyloidosis (gelatinous drop-like corneal dystrophy): exclusion of linkage to lactoferrin gene.

PURPOSE: Because corneal tissue with familial subepithelial corneal amyloidosis (FSCA; gelatinous drop-like dystrophy of the cornea) contains lactoferrin the possibility that the FSCA gene was the human lactoferrin (hLF) gene was investigated. Due to contradictory published information we also mapped the hLF gene. METHODS: We mapped the hLF gene using a genomic clone of the entire hLF gene as a probe by fluorescence in situ hybridization (FISH). Utilizing PCR primers that are specific to the hLF gene, we also mapped the hLF via radiation somatic cell hybrid analysis. Linkage of the FSCA gene to the hLF gene was evaluated by genetic linkage analysis using polymorphic markers within and in the vicinity of the hLF gene. RESULTS: The hLF gene mapped to the short arm of chromosome 3 at 3p21. Linkage analysis using polymorphic markers for hLF and haplotype analysis of the 3p21 loci indicates that the FSCA gene is not linked to the 3p21 locus. CONCLUSIONS: The gene for FSCA is not the hLF gene in these families.

Amyloidosis↗
PubMed1998

Unconjugated estriol as an indication for prenatal diagnosis of steroid sulfatase deficiency by in situ hybridization.

BACKGROUND: Undetectable or very low unconjugated estriol (E3) levels in routine maternal serum screening are associated with steroid sulfatase deficiency, miscarriages, and anencephaly. CASES: Fluorescence in situ hybridization techniques were used in the diagnosis of steroid sulfatase deficiency prenatally in three cases with low or undetectable unconjugated E3 levels. Results showed a male fetus with a deleted steroid sulfatase region, but intact Kallmann syndrome region in all three cases. One mother was studied by fluorescence in situ hybridization and showed a similar deletion for steroid sulfatase gene in one copy of X chromosome (carrier). CONCLUSION: Women with undetectable or very low levels of estriol on serum screening should be counseled regarding steroid sulfatase deficiency with evaluation by fluorescence in situ hybridization.

Adult↗
PubMed1997

Genomic structure and chromosomal localization of the novel ETS factor, PE-2 (ERF).

The members of the ETS family of transcription factors are grouped because they share a highly conserved DNA binding domain. These factors are involved in growth factor pathways and regulate both proliferation and differentiation. To identify ETS factors that may be involved in early hematopoietic progenitor regulation, we isolated a novel member of the ETS family by reverse transcriptase-PCR of the conserved DNA binding domain using degenerate oligonucleotides. This gene directs the synthesis of a 2704-nucleotide transcript whose largest open reading frame encodes a 548-amino-acid protein. Northern blot analysis reveals ubiquitous expression in all human tissues and cell lines tested, with highest levels in the testis, ovary, pancreas, and heart. Comparison of this gene with the available databases reveals very significant homology to the ETS factor PE-1 and probable near-identity with the recently cloned factor ERF. The PE-2 gene is composed of four exons spanning over 9 kb of genomic DNA. Sequence analysis of the promoter region reveals a GC-rich sequence without a TATA motif and with putative binding motifs for CREB, c-myb, and AP-1 factors. Using mouse-human somatic hybrids and FISH analysis, the PE-2 gene is localized to human chromosome 19q13.2, a region involved in translocations and deletions in leukemias and several solid tumors, suggesting that this novel ETS factor may play a role in carcinogenesis.

Amino Acid Sequence↗
PubMed1995

Effectiveness of percutaneous nephrostomy in reversing obstructive renal failure.

A retrospective analysis of 34 patients of obstructive renal failure, initially managed by percutaneous nephrostomy was performed. Pre procedure blood biochemical profile was compared with upto one week follow-up of blood chemistry. There was a decline of 71.1% and 56.08% (P-values 0.0001 and 0.0028) in the mean values of serum creatinine and blood urea nitrogen respectively at 7 days after the procedure. Improvement in blood biochemical profile was solely dependent on performance of percutaneous nephrostomy.

Adolescent↗
PubMed1992

Removal of basic dye from waste-water using silica as adsorbent.

The kinetics of removal of Basic Blue 3 from a textile effluent was studied using silica as an adsorbent. The adsorption was found to follow a first-order process. The influences on the rate of adsorption of various factors, such as temperature, concentration of dye solution, pH of the system and the amount of adsorbent have been investigated. On the basis of the isotherm studies, the various thermodynamical parameters have been calculated. The effect of electrolytes and surfactants has also been seen on the removal of the dye from the waste-water.

Journal Article↗