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Biomedical subjects

M E Williams

Publications and source records attributed to M E Williams.

At least 55 records · Page 3Linked to original sources
PubMed1996

Cyclin D1 gene expression in human cervical neoplasia.

Amplification of chromosome 11q13 leads to overexpression of a G1 cyclin gene, cyclin D1 (PRAD-1, CCND-1), in many non-cervical human carcinomas. Homology between cyclin D1 and human papillomavirus oncoprotein E7 binding sites for the retinoblastoma tumor-suppressor protein suggests that human papillomavirus oncoproteins cyclin D1, and other cell cycle regulatory proteins may act through a common mechanism in the pathogenesis of human cervical squamous cell carcinoma. We have examined 48 cases of cervical neoplasia by RNA-mRNA in situ hybridization for human papillomavirus mRNA and cyclin D1 mRNA and by immunohistochemistry for cyclin D1 protein expression. Hybridization demonstrated human papillomavirus RNA in all 48 cases with types 6, 16, or 18 in 2, 26, and 20 cases, respectively. Immunohistochemical detection using anti-cyclin D1 rabbit polyclonal antibody 19 demonstrated appropriate cyclin D1 expression at constitutive low levels in normal squamous epithelium and low-grade intraepithelial lesions. Immunohistochemical staining failed to demonstrate significant protein expression in any of the high-grade or invasive lesions. In contrast to the immunohistochemical results, in situ hybridization demonstrated cyclin D1 mRNA overexpression in three of five cases of low-grade squamous intraepithelial lesion, one of eight cases of high-grade squamous intraepithelial lesion, 14 of 18 cases of invasive squamous cell carcinoma, two of five cases of adenocarcinoma in situ, one of seven cases of invasive adenocarcinoma, and two of five cases of small cell undifferentiated carcinoma. Transcriptional activation of cyclin D1 can occur in vivo in human papillomavirus-associated invasive cervical carcinoma, but it does not seem to result in a steady state, increased level of cyclin D1 protein expression. These data indicate a limited role for cyclin D1 protein in the pathogenesis of human papillomavirus-associated invasive cervical squamous carcinoma. They support a model in which human papillomavirus proteins can circumvent cellular requirements for cyclin D1 in human cervical neoplasia.

Carcinoma↗
PubMed1996

Immunohistochemical detection and gene amplification of cyclin D1 in mammary infiltrating ductal carcinoma.

The deregulation of cyclin D1 (BCL-1, PRAD1, CCND1) protein, normally synthesized in the G1 phase of the cell cycle, has been implicated in the pathogenesis of some malignant neoplasms, including invasive mammary carcinomas. We used rabbit polyclonal antibody 19 to detect cyclin D1 in 55 infiltrating ductal carcinomas and compared the findings to six important clinicopathologic parameters and cyclin D1 gene amplification. Nuclear immunoreactivity of variable intensity for cyclin D1 was present in 35% of the neoplasms, whereas immunoreactivity of normal mammary epithelial nuclei was absent. No significant correlations were observed between immunoreactivity and patient age, axillary lymph node status, estrogen receptors, progesterone receptors, histologic grade, or any of its three components. There was a correlation between cyclin D1 immunostaining and tumor size (P = 0.013). Fourteen of 15 tumors 2 cm or less were negative, whereas 7 of 12 neoplasms larger than 4 cm were immunopositive. Fifteen percent of the invasive carcinomas had cyclin D1 gene amplification. Of these eight tumors, six showed cyclin D1 immunoreactivity (P = 0.017). In this study, cyclin D1 was detected immunohistochemically in approximately one-third of infiltrating ductal carcinomas; approximately one-third of these had detectable cyclin D1 gene amplification. These results further implicate cyclin D1 in breast tumorigenesis and are additional evidence for the role of cell cycle regulatory proteins in invasive mammary carcinoma.

Adult↗
PubMed1995

Chromosomal localization of the human genes for alpha 1A, alpha 1B, and alpha 1E voltage-dependent Ca2+ channel subunits.

The alpha 1 subunit genes encoding voltage-dependent Ca2+ channels are members of a gene family. We have used human brain cDNA probes to localize the neuronal isoform genes CACNL1A4 (alpha 1A), CACNL1A5 (alpha 1B), and CACNL1A6 (alpha 1E) to 19p13, 9q34, and 1q25-q31, respectively, using fluorescence in situ hybridization on human chromosomes. These genes are particularly interesting gene candidates in the pathogenesis of neuronal disorders. Although genetic disorders have been linked to loci 9q34 and 19p13, no genetic disease related to Ca2+ signaling defects has yet been linked to these loci.

Calcium Channels↗
PubMed1995

Cellular and molecular events in a newly organizing lateral root meristem.

Spontaneous or auxin-induced lateral root formation in radish and Arabidopis provides an efficient system in which to examine molecular and cellular events associated with the initiation of a new meristem. Subtracted cDNA libraries made at different times in lateral root initiation were used as a source of genes that are expressed differentially during this developmental process, and expression studies on a small gene family of ribosomal protein genes were conducted. From analysis of cell division patterns in pericycle cells the number of founder cells for lateral roots was established. By the use of in vitro growth assays lateral root formation was determined to be a two-stage process. First a primordium is formed, and subsequently a subset of primordial cells begins to function as the lateral root apical meristem. This mode of root development has implications for pattern formation in newly organizing organs.

Arabidopsis↗
PubMed1995

Vaccination routes that fail to elicit protective immunity against Schistosoma mansoni induce the production of TGF-beta, which down-regulates macrophage antiparasitic activity.

C57BL/6 mice immunized intradermally (i.d.) with bacillus Calmette Guerin (BCG) plus killed skin-stage schistosomula are protected against subsequent infection with Schistosoma mansoni, whereas immunization by i.v. or i.m. routes is not protective. Moreover, previous immunization via the nonprotective i.v. route interfered with the ability to subsequently induce protection by i.d. vaccination, suggesting that inhibitory responses are invoked. Given the evidence that activated macrophages (M phi) play a role as effector cells in protection against schistosomiasis, we investigated the ability of spleen cells from protected and nonprotected immunized mice to produce M phi activating and deactivating cytokines. Exposure to supernatant fluids (SNs) from Ag stimulated spleen cells of i.d., but not i.v. or i.m., immunized mice activated inflammatory M phi for in vitro killing of schistosome larvae, through a mechanism dependent on both IFN gamma and TNF-alpha. No evidence was observed for the preferential induction of the M phi activating Th1 cytokines IFN-gamma and IL-2 in i.d. immunized mice, nor did spleen cells from nonprotected animals produce higher levels of the Th2 associated cytokines IL-4 and IL-10, which are known to prevent M phi activation. TGF-beta was, however, detected in SNs from unprotected mice. Moreover, the M phi inhibitory activity detected in these SNs was heat stable and neutralized by anti-TGF-beta Abs, suggesting that production of TGF-beta is at least partially responsible for the failure of i.m. and i.v. immunized mice to develop immunity to S. mansoni. Thus, the induction of down-regulatory cytokines may be an important factor limiting the efficacy of certain vaccination protocols.

Animals↗
PubMed1995

Targeting the maize T-urf13 product into tobacco mitochondria confers methomyl sensitivity to mitochondrial respiration.

The URF13 protein, which is encoded by the maize mitochondrial T-urf13 gene, is thought to be responsible for pathotoxin and methomyl sensitivity and male sterility. We have investigated whether T-urf13 confers toxin sensitivity and male sterility when expressed in another plant species. The coding sequence of T-urf13 was fused to a mitochondrial targeting presequence, placed under the control of the cauliflower mosaic virus 35S promoter, and introduced into tobacco by Agrobacterium tumefaciens-mediated transformation. Plants expressing high levels of URF13 were methomyl sensitive. Subcellular analysis indicated that URF13 is mainly associated with the mitochondria. Adding methomyl to isolated mitochondria stimulated NADH-linked respiration and uncoupled oxidative phosphorylation, indicating that URF13 was imported into the mitochondria, and conferred toxin sensitivity. Most control plants, which expressed the T-urf13c construct lacking the mitochondrial presequence, were methomyl sensitive and contained URF13 in a membrane fraction. Subcellular fractionation by sucrose gradient centrifugation showed that URF13 sedimented at several positions, suggesting the protein is associated with various organelles, including mitochondria. No methomyl effect was observed in isolated mitochondria, however, indicating that URF13 was not imported and did not confer toxin sensitivity to the mitochondria. Thus, URF13 confers toxin sensitivity to transgenic tobacco with or without import into the mitochondria. There was no correlation between the expression of URF13 and male sterility, suggesting either that URF13 does not cause male sterility in transgenic tobacco or that URF13 is not expressed in sufficient amounts in the appropriate anther cells.

Amino Acid Sequence↗
PubMed1995

Chromosome 11q13 amplification in head and neck squamous cell carcinoma. Association with poor prognosis.

OBJECTIVE: To determine the clinical and prognostic significance of chromosome 11q13 amplification in squamous cell carcinoma of the head and neck. DESIGN: Retrospective clinical analysis. SETTING: University and private cancer centers. PATIENTS: Fifty-six patients with pathologically confirmed head and neck squamous cell carcinoma whose tumors had been assayed for the presence or absence of chromosome 11q13 amplification. MEASUREMENTS: The degree of DNA amplification in each tumor was determined using chromosome 11q13 probes for the bcl-1 major translocation cluster, PRAD1/cyclin D1 (CCND1), the fibroblast growth factor gene HST1, EMS1, and glutathione-S-transferase-pi-1. The presence or absence of amplification in each patient was correlated with primary site, tumor stage, nodal status, presence or absence of distant metastasis, disease recurrence, time to recurrence, clinical outcome (disease status), and overall survival. RESULTS: Amplification of chromosome 11q13 was identified in 39% (22/56) of patients. Recurrent or persistent disease was identified in 82% (18/22) of cases with amplification and 50% (14/28) of nonamplified cases (P = .04). Mean time to recurrence was shorter in cases with amplification (6.2 months) than those without amplification (10.1 months) (P = .01). Eighteen patients (82%) with amplification and 10 patients (38%) without amplification died of disease or are alive with disease (P = .001). The mean follow-up period was 15.8 months for patients with amplification and 18.6 months for patients without amplification. Overall survival was significantly diminished in patients with amplification (P = .002). Amplification was not related to nodal status, distant metastases, or initial disease stage. CONCLUSIONS: Amplification of chromosome 11q13 loci may be an important biologic marker indicating poor prognosis, independent of clinical stage in head and neck squamous cell carcinoma, and it should be assessed in prospective trials to determine its utility for stratifying treatment and determining prognosis.

Adult↗
PubMed1995

Expression of cyclin D1 protein in centrocytic/mantle cell lymphomas with and without rearrangement of the BCL1/cyclin D1 gene.

Centrocytic/mantle cell lymphoma (CC/MCL) is a morphologically defined B-cell non-Hodgkin's lymphoma characterized by a distinctive immunophenotype, BCL1/cyclin D1 (PRAD1) gene rearrangements, and, most recently, by overexpression of cyclin D1. Even using multiple breakpoint probes for BCL1 (MTC, p94PS) and cyclin D1, however, only approximately 70% of CC/MCL have a rearrangement consistent with a t(11;14) (q13;q32). To determine whether the type of molecular translocation affects the degree of cyclin D1 expression and to evaluate lymphomas diagnosed as CC/MCL but lacking molecular evidence of a BCL1 or cyclin D1 translocation, 16 CC/MCL and four cases of small lymphocytic lymphoma/B-CL1 (SLL/B-CLL) were stained using an anti-cyclin D1 antibody. All cases with a cyclin D1 translocation detected by Southern blotting techniques as well as four of the five CC/MCL without a documentable translocation showed nuclear cyclin D1 protein expression. There was no apparent correlation between staining intensity and the precise site or presence of a detectable translocation. Cases with a mantle zone growth pattern showed infiltration of the cyclin D1 positive cells into reactive follicular centers. None of the four SLL/B-CLL showed cyclin D1 expression. These findings show overexpression of the cyclin D1 protein in virtually all CC/MCL independent of the type or presence of a documentable BCL1 or cyclin D1 molecular rearrangement. The mechanism for cyclin D1 overexpression in the cases without a documentable rearrangement and the relationship of cyclin D1 overexpression to the pathogenesis of mantle cell neoplasia remain uncertain.

Cyclin D1↗
PubMed1995

Cyclin D1 (PRAD1, CCND1) and glutathione-S-transferase pi gene expression in head and neck squamous cell carcinoma.

Chromosome 11q13 amplification has been identified in a subset of head and neck squamous cell carcinomas (H&N SCCs). This region contains several putative oncogenes, including cyclin D1 (PRAD1, CCND1), which encodes for an important cell cycle regulatory protein, and the locus encoding for the drug-detoxifying enzyme glutathione-S-transferase-pi (GST-pi). To determine the relationship of cyclin D1 and GST-pi gene amplification to expression of the encoded proteins, the authors examined 64 H&N SCCs by both Southern blot hybridization and immunohistochemistry, using a recently described, affinity-purified, anticyclin D1 polyclonal antibody no. 19 as well as a polyclonal antibody against GST-pi. Anticyclin D1 antibody no. 19 labeled the tumor cell nuclei in 28 (44%) of the H&N SCCs, whereas cytoplasmic immunoreactivity for GST-pi was noted in 55 (86%) neoplasms. By Southern blot 24 tumors (37.5%) showed twofold to tenfold amplification of 11q13 loci; only two of these were coamplified for GST-pi. Immunopositivity with anticyclin D1 antibody no. 19 but not anti-GST-pi significantly correlated with 11q13 amplification (P < .0001). Of the 28 tumors positive with anticyclin D1 antibody no. 19, however, only 18 (64%) were amplified for 11q13, and six amplified tumors did not react with the no. 19 antibody. A strong trend was noted between anticyclin D1 antibody no. 19 reactivity and a hypopharyngeal primary site (P = .053), but no correlations were observed between immunoreactivity and cytological grade, architectural pattern, pathological stage, and disease-free or overall survival. The inconsistent association of cyclin D1 immunoreactivity with 11q13 amplification indicates that other mechanisms may exist for protein overexpression. Immunoreactivity for the GST-pi protein is prevalent in H&N SCC but is clearly unassociated with amplification. In this series, the presence or extent of cyclin D1 and GST-pi immunoreactivity was of no proven prognostic benefit in H&N SCC.

Adult↗
PubMed1995

Developmental regulation of ribosomal protein L16 genes in Arabidopsis thaliana.

Lateral roots can be synchronously induced in Arabidopsis by a brief auxin treatment. An early event in the development of a lateral root primordium is the accumulation of mRNAs encoding ribosomal proteins. In situ hybridizations show that mRNA encoding one ribosomal protein, L16, accumulates in all rapidly proliferating tissues including the shoot and root apical meristems and lateral root primordia. To understand further the mechanisms by which ribosomal proteins are coordinately synthesized, two genes encoding the ribosomal protein L16 were isolated from Arabidopsis thaliana. Promoter sequences from each RPL16A and RPL16B were fused to the beta-glucuronidase reporter gene GUS. The promoter of RPL16B(from -848 to -19) conferred X-Gluc staining in proliferating tissues including the shoot and root apical meristems. When GUS was expressed from the RPL16A promoter (from -875 to -22), X-Gluc staining was observed in cells in the root stele and in anthers. When seedlings transformed with either promoter construct were treated with auxin to induce lateral roots, X-Gluc staining accumulated in the lateral root primordia by 16 h after induction. Transcription of the RPL16B promoter appears to be correlated with cell division, while transcription of the RPL16A promoter is very cell specific. Expression of two genes encoding L16 during the early phase of lateral root initiation and in developing pollen may serve to increase levels of ribosomal proteins during the rapid growth of these tissues.

Amino Acid Sequence↗
PubMed1995

In situ hybridization detection of cyclin D1 mRNA in centrocytic/mantle cell lymphoma.

BACKGROUND: Centrocytic/mantle cell lymphoma (MCL) is characterized by a specific chromosomal translocation, t(11;14)(q13;q32), which leads to deregulated expression of the G1 cyclin, cyclin D1 (PRAD1, CCND1, BCL1). Cyclin D1 overexpression has been demonstrated in MCL at the mRNA level by Northern blotting and at the protein level by both Western blotting and immunoperoxidase staining. PATIENTS AND METHODS: To assess the utility of in situ hybridization (ISH) to detect cyclin D1 mRNA expression in formalin-fixed, paraffin embedded tissue, five MCL specimens from three patients and two cases of B-cell small lymphocytic lymphoma (B-SLL) were studied. BCL1 major translocation cluster gene rearrangements had been previously documented in two MCL patients; the other MCL and the two B-SLL, showed no detectable BCL1 or cyclin D1 rearrangements. RESULTS: ISH was performed using anti-sense 3H-labeled RNA probes for the cyclin D1 3' untranslated region (pPL7) and partial cyclin D1 cDNA (pPL8). ISH experiments using an anti-sense actin RNA probe demonstrated adequate RNA preservation in all cases. Each of five specimens of MCL demonstrated increased cyclin D1 mRNA. In contrast, neither of the two cases of B-SLL demonstrated detectable levels. CONCLUSIONS: Overexpression of cyclin D1 mRNA can be detected in MCL by ISH using formalin fixed paraffin embedded tissue. The ISH technique may be useful in diagnosing and classifying low-grade B-cell lymphomas and should be applicable to the study of cyclin D1 mRNA expression in a broad spectrum of lymphoid proliferations and solid tumors.

Cyclin D1↗
PubMed1995

Paracortical nodular T-cell lymphoma. Identification of an unusual variant of peripheral T-cell lymphoma.

Peripheral T-cell lymphomas (PTCLs) are regarded as diffuse proliferations. We describe an unusual paracortical nodular growth pattern in four nodal PTCLs that were initially interpreted as atypical lymphoid hyperplasia in three patients and small B-cell lymphoma with plasmacytic differentiation in a fourth. The nodules were vague to easily discernible and produced minimal to partial architectural distortion. Sinuses were often open, and scattered cortical lymphoid follicles with atretic to hyperplastic germinal centers were present. Clusters of tumor cells abutted some follicles in all cases, and in one case they exhibited focal T-zone expansion. Hypervascularity was not prominent, but a few nodules surrounded epithelioid venules, imparting an angiofollicular appearance. The nodules were composed primarily of small lymphocytes with irregular nuclei admixed with scattered large transformed cells, both cell types having clear cytoplasm. Paraffin immunoperoxidase showed that the nodules were composed of T cells. Dendritic cell networks were present only in follicular centers. Southern blot analysis found T-cell receptor gene rearrangements and a germline immunoglobulin gene configuration in all four nodes. These paracortical clear cell nodules of clonal T cells may be a special type of PTCL. Alternatively, they may represent early foci of lymphoma or they may be a subgroup of T-zone lymphoma. Paracortical nodular PTCL must be differentiated from atypical hyperplastic lesions and some B-cell lymphomas.

Aged↗
PubMed1995

Use of unproven therapies by people with Alzheimer's disease.

OBJECTIVE: To describe the use of unproven therapies for Alzheimer's disease. DESIGN: Descriptive survey using a written questionnaire. PARTICIPANTS: 101 primary caregivers of people with Alzheimer's disease who attended Alzheimer's disease support group meetings. RESULTS: Fifty-five percent of caregivers reported that they had tried at least one alternative therapy to improve the patient's memory. Twenty percent of caregivers tried three or more unproven therapies. Vitamins were used most frequently (84%), and health foods (27%), herbal medicines (11%), "smart pills" (9%), and home remedies (7%) were also tried. Most caregivers reported trying the therapies in the early stage of the illness and did not notice significant improvement in the patient's memory. Twenty-five percent of caregivers had tried unproven therapies for behavior problems. There was no correlation between the use of alternative therapies and the sex of the caregiver, age of the caregiver, level of caregiver frustration, presence of problem behaviors, or perceived level of physician support. CONCLUSIONS: The use of unproven therapies by people with early Alzheimer's disease is common and cannot be predicted by characteristics of the primary caregiver. Although this use may be understandable, it exposes vulnerable people to possible side effects, increased costs, and possible exploitation. Health care workers should actively inquire about the use of alternative therapies, and explore the reasons behind their use, so that they can better understand and meet the needs of their patients and their caregivers.

Aged↗
PubMed1995

Formation of lateral root meristems is a two-stage process.

In both radish and Arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the root. In Arabidopsis, the number of pericycle cells that divide to form a primordium was estimated to be about 11. To determine the stage at which primordia are able to function as root meristems, primordia of different stages were excised and cultured without added hormones. Under these conditions, primordia that consist of 2 cell layers fail to develop while primordia that consist of at least 3-5 cell layers develop as lateral roots. We hypothesize that meristem formation is a two-step process involving an initial period during which a population of rapidly dividing, approximately isodiametric cells that constitutes the primordium is formed, and a subsequent stage during which meristem organization takes place within the primordium.

Arabidopsis↗