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Biomedical subjects

E Smith

Publications and source records attributed to E Smith.

At least 127 records · Page 7Linked to original sources
PubMed1998

Frequency of voice problems among teachers and other occupations.

This study describes the frequency of reporting vocal problems among a random sample of elementary and high school teachers (n = 554) compared to individuals working in other occupations (n = 220). Teachers were more likely to define themselves as ever having a voice problem (32% versus. 1%, p < .05); having a tired, weak, or effortful voice (p < .05 each); and having a higher frequency of symptoms of physical discomfort with speaking (p < .05). They also were more likely to perceive that their voice problem negatively affected current job performance (p < .05) and limited options regarding change in work (p < .05). About 20% of teachers but only 4% of nonteachers had missed work due to their voice. These findings suggest that teachers are at high-risk for disability from voice disorders and that this health problem may have significant work-related and economic effects.

Adult↗
PubMed1998

Functional impact of nodules: a case-comparison study.

Patients diagnosed with nodules (NO = 40) in a large university hospital clinic and an age-stratum matched nondiseased group (ND = 200) described adverse outcomes of vocal impairment on work and work-related communications. NOs were significantly more likely than NDs to report symptoms of hoarseness (73% vs. 26%), high-note difficulty (70% vs. 20%), difficulty speaking with a lower voice (53% vs. 13%) and a tired voice (50% vs. 10%), and their greatest source of physical discomfort was associated with scratchiness (61% vs. 3%). The average number of symptoms was four in NOs and less than one in NDs. Nodule patients were most concerned about the effects their voice problem would have on their future career (78% vs. 24%) and 49% of NOS reported their voice problem had an adverse work effect in the past compared with 4% of NDs. Having a voice condition limited current job performance in 39% of the NO group but only in 2% of the ND group. The results suggest that a diagnosis of nodules plays a major role in disrupting careers and work activities and that available educational programs and additional research are needed for improving their functional ability and preventing adverse outcomes in the lives of individuals with voice disorders.

Adolescent↗
PubMed1998

Expression analysis of a sucrose carrier in the germinating seedling of Ricinus communis.

This study describes the expression of a sucrose carrier at various developmental stages in Ricinus communis. A partial-length cDNA clone, RcSUT1, was isolated by RT-PCR from Ricinus seedling RNA. This is almost identical to a sucrose carrier cDNA, Rscr1, which has previously been isolated by library screening. However, we have observed a very different expression pattern in the seedling to that previously reported. Northern analysis, with RcSUT1 as a probe, revealed high expression of a 2 kb transcript in the cotyledons of the germinating seedling; transcript levels were similar in cotyledons harvested 3-6 days after germination. A much lower level of this transcript was detected in the root, hypocotyl and endosperm RNA of the seedling and very low levels were also present in the sink and source leaves of the mature plant. This pattern of expression was also reflected at the protein level with an antipeptide antibody raised to part of the RcSUT1 deduced amino acid sequence. Tissue print hybridisation analysis of the hypocotyl revealed that the sucrose carrier transcripts were localised to the phloem cells of the vascular bundles. A more detailed analysis of sucrose carrier gene expression in the cotyledons of the germinating seedling was carried out by in situ hybridisation; the strongest signals were observed from the lower epidermal layer and the phloem, consistent with an active loading role for these cells. An ultrastructural study of the cells in the lower epidermis showed that they have wall ingrowths which are characteristic of transfer cells. The results are discussed in relation to the physiological role of the sucrose carrier in the Ricinus seedling and to the pathways of sucrose movement from endosperm to the sieve elements in the cotyledons.

Amino Acid Sequence↗
PubMed1998

Targeted disruption of the biglycan gene leads to an osteoporosis-like phenotype in mice.

The resilience and strength of bone is due to the orderly mineralization of a specialized extracellular matrix (ECM) composed of type I collagen (90%) and a host of non-collagenous proteins that are, in general, also found in other tissues. Biglycan (encoded by the gene Bgn) is an ECM proteoglycan that is enriched in bone and other non-skeletal connective tissues. In vitro studies indicate that Bgn may function in connective tissue metabolism by binding to collagen fibrils and TGF-beta (refs 5,6), and may promote neuronal survival. To study the role of Bgn in vivo, we generated Bgn-deficient mice. Although apparently normal at birth, these mice display a phenotype characterized by a reduced growth rate and decreased bone mass due to the absence of Bgn. To our knowledge, this is the first report in which deficiency of a non-collagenous ECM protein leads to a skeletal phenotype that is marked by low bone mass that becomes more obvious with age. These mice may serve as an animal model to study the role of ECM proteins in osteoporosis.

Age Factors↗
PubMed1998

Increased expression of TGF-beta receptors by scleroderma fibroblasts: evidence for contribution of autocrine TGF-beta signaling to scleroderma phenotype.

Scleroderma fibroblasts exhibit numerous phenotypic differences when compared with healthy skin fibroblasts. Some of these differences, in particular overexpression of collagen type I and other extracellular matrix proteins, parallel the effect of transforming growth factor-beta (TGF-beta) on dermal fibroblasts, suggesting that the scleroderma fibroblast phenotype may result from activation of autocrine TGF-beta signaling. To test this hypothesis we examined the role of TGF-beta Type I and Type II receptors in regulating collagen type I transcription. We have shown that overexpression of either Type I or Type II receptors significantly (3-4-fold) increases alpha2 (I) collagen promoter activity in transient transfection assays in dermal fibroblasts. Addition of anti-TGF-beta antibody abolished, whereas addition of plasmin enhanced, the stimulatory effect of receptor overexpression on collagen promoter activity, suggesting that this effect depends on autocrine TGF-beta. Moreover, these cotransfection experiments indicated that expression levels of TGF-beta receptors is a limiting factor in the autocrine regulation of collagen type I transcription by TGF-beta. Comparison of the TGF-beta receptor Type I and Type II mRA expression levels in scleroderma and normal fibroblasts have indicated elevated expression (2-fold) of both receptor types in scleroderma cells, which correlated with increased binding of TGF-beta. Significantly, elevated TGF-beta receptor levels correlated with elevated alpha2 (I) collagen mRNA levels. These results suggest that the elevated production of collagen type I by scleroderma fibroblasts results from overexpression of TGF-beta receptors.

Collagen↗
PubMed1998

Knowledge of HIV-positivity had no impact on AIDS survival time among Danish AIDS patients 1980-95.

OBJECTIVE: To examine the impact of the time period from first positive HIV test to AIDS diagnosis and other variables on survival after AIDS diagnosis. MATERIALS AND METHODS: All adult AIDS patients diagnosed and reported to the national surveillance unit in Denmark in the period 1980 through June 1995. RESULTS: A total of 1745 patients was diagnosed in the period, and for 1631 (93.5%) the date of first positive HIV test was known. The median interval between this test and AIDS diagnosis was 912 d. Overall, 473 patients (29.0%) were found to be HIV-positive close to the AIDS diagnosis (< or = 4 months). The time interval between first positive HIV test and AIDS diagnosis varied by transmission categories. Patients older than 40 y had a higher mortality than younger patients. Patients infected by blood products had the highest mortality. The survival time was shortest for patients presenting with HIV-wasting or HIV-encephalopathy or with > or = 1 AIDS-defining disease. The time interval between first positive HIV test and AIDS diagnosis had no impact on survival. CONCLUSION: No association was found between survival time and the time interval between first positive HIV test and AIDS diagnosis. Older age and transmission by blood or blood products were associated with shorter survival from AIDS diagnosis.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Sporadic imprinting defects in Prader-Willi syndrome and Angelman syndrome: implications for imprint-switch models, genetic counseling, and prenatal diagnosis.

The Prader-Willi syndrome (PWS) and the Angelman syndrome (AS) are caused by the loss of function of imprinted genes in proximal 15q. In approximately 2%-4% of patients, this loss of function is due to an imprinting defect. In some cases, the imprinting defect is the result of a parental imprint-switch failure caused by a microdeletion of the imprinting center (IC). Here we describe the molecular analysis of 13 PWS patients and 17 AS patients who have an imprinting defect but no IC deletion. Heteroduplex and partial sequence analysis did not reveal any point mutations of the known IC elements, either. Interestingly, all of these patients represent sporadic cases, and some share the paternal (PWS) or the maternal (AS) 15q11-q13 haplotype with an unaffected sib. In each of five PWS patients informative for the grandparental origin of the incorrectly imprinted chromosome region and four cases described elsewhere, the maternally imprinted paternal chromosome region was inherited from the paternal grandmother. This suggests that the grandmaternal imprint was not erased in the father's germ line. In seven informative AS patients reported here and in three previously reported patients, the paternally imprinted maternal chromosome region was inherited from either the maternal grandfather or the maternal grandmother. The latter finding is not compatible with an imprint-switch failure, but it suggests that a paternal imprint developed either in the maternal germ line or postzygotically. We conclude (1) that the incorrect imprint in non-IC-deletion cases is the result of a spontaneous prezygotic or postzygotic error, (2) that these cases have a low recurrence risk, and (3) that the paternal imprint may be the default imprint.

Angelman Syndrome↗
PubMed1998

Idiopathic pulmonary fibrosis and cyclosporine: a lesson from single-lung transplantation.

Idiopathic pulmonary fibrosis (IPF) has a poor prognosis and therapeutic options are limited with a 5-year survival of less than 50%. This report includes a case of histologically confirmed IPF in a patient whose native lung showed objective improvement as measured by high-resolution CT while he was receiving cyclosporine-based immunosuppressive therapy after single-lung transplantation.

Cyclosporine↗
PubMed1997

Construction and characterization of vaccinia direct ligation vectors.

Poxvirus vectors are extensively used as expression vehicles for protein and antigen expression in eukaryotic cells. Customarily, the foreign DNA is introduced into the poxvirus genome by homologous recombination. An alternative method using direct ligation vectors has been used to efficiently construct chimeric genomes in situations not readily amenable for homologous recombination. We describe the construction and characterization of a new set of direct ligation vectors designed to be universally applicable for the generation of chimeric vaccinia genomes. These vectors contain the pair of unique restriction sites NotI and ApaI to eliminate religation of poxvirus arms and fix the orientation of the insert DNA behind strongly expressing constitutive vaccinia promoters. The insertion cassette has been placed at the beginning of the thymidine kinase gene in vaccinia to use drug selection in the isolation of recombinants. These viruses provide a set of universally applicable direct ligation poxvirus cloning vectors, extending the utility of poxvirus vectors for construction and expression of complex libraries.

Animals↗
PubMed1997

Results of high-dose therapy and autologous bone marrow/stem cell transplantation during remission in poor-risk intermediate- and high-grade lymphoma: international index high and high-intermediate risk group.

We have conducted a pilot study to investigate the role of high-dose therapy and autologous bone marrow/stem cell transplantation (ASCT) during first complete or partial remission in 52 patients with poor-risk aggressive lymphoma. There were 42 patients with intermediate-grade or immunoblastic lymphoma who were considered to be high (60%) and high-intermediate risk (40%) groups at diagnosis based on the age-adjusted International Prognostic Index (IPI) and 10 patients with high-grade, SNCCL (small non-cleaved cell, Burkitt's, and non-Burkitt's), who at presentation had poor-risk features defined as elevated serum lactate dehydrogenase level, stage IV, and bulky mass >/=10 cm. The median age was 34 years (range, 16 to 56 years). Thirty-nine were transplanted in first complete remission and 13 in first partial remission after conventional therapy. Conditioning regimens consisted of total body irradiation (TBI) administered as a single fraction 750 cGy in 3 patients and in fractionated doses for a total of 1,200 cGy in 44 patients, in combination with 60 mg/kg etoposide and 100 mg/kg cyclophosphamide. Five patients with prior radiotherapy received 450 mg/m2 carmustine instead of TBI. Stem cell sources were either bone marrow and/or peripheral blood. No in vitro purging was used. All patients engrafted. Two SNCCL patients died of venoocclusive disease at 25 days and acute leukemia at 27 months posttransplantation. There were six relapses at 1.5 to 12.8 months posttransplantation. At a median follow-up of 44 months (range, 1 to 113 months), the estimated 3-year overall survival (OS) and disease-free survival (DFS) for all patients was 84% (95% confidence interval [CI], 70% to 92%) and 82% (95% CI, 68% to 91%), respectively. In the subset of patients with intermediate-grade and immunoblastic lymphoma, the 3-year DFS was 89% (95% CI, 74% to 96%) for all patients, 87% (95% CI, 67% to 96%) for high-risk patients, and 92% (95 CI, 61% to 99%) for high-intermediate risk patients. The 3-year OS and DFS for SNCCL patients were identical at 60% (95% CI, 30% to 84%). These results suggest that high-dose therapy and ASCT during first remission may improve the survival and prognosis of patients with poor-risk intermediate- and high-grade lymphoma. A prospective randomized study comparing high-dose therapy and ASCT with conventional chemotherapy in IPI high-risk patients with aggressive non-Hodgkin's lymphoma should be undertaken.

Adolescent↗
PubMed1997

Epidemiologic analysis of Mycoplasma spp isolated from bulk-tank milk samples obtained from dairy herds that were members of a milk cooperative.

OBJECTIVE: To determine the prevalence of Mycoplasma spp in herds that were members of a milk cooperative. DESIGN: Epidemiologic study. SAMPLE POPULATION: 267 dairy herds that were members of a milk cooperative. PROCEDURE: Bulk-tank milk samples were collected monthly during a 6-year period from all dairies in the cooperative. Samples were submitted to the cooperative's laboratory for bacterial culture for Mycoplasma spp, using direct plating. Milk samples positive for Mycoplasma organisms were speciated. RESULTS: Prevalence of positive samples varied from 1.8 to 5.8% for all species of Mycoplasma and from 1.2 to 3.1% for Mycoplasma spp known to be mastitis pathogens. One mycoplasmal species was isolated initially on 99 of 198 (50.0%) dairies, but 68 of 198 (34.3%) dairies had 2 species isolated. Mycoplasma bovis, M californicum, and M bovigenitalium were consistently isolated, but M bovis (243/499; 48.6%) was the most commonly isolated species. Acholeplasma laidlawii was more prevalent in 1989 and 1995 than other years. Mycoplasma bovigenitalium and M californicum had a seasonal distribution. Less than 50 colonies per plate were isolated for most (317/500; 63.4%) bulk-tank samples. Of the milk samples with > 100 colonies/plate, Mycoplasma bovis was isolated most frequently (73/243; 30.0%). CLINICAL IMPLICATIONS: Distribution of Mycoplasma spp varied by year, number of colonies isolated per sample, season, and herd. Therefore, it may be necessary to routinely sample bulk-tank milk, and all isolates should be speciated. Culture results from milk cooperatives should be used with other monitoring information to determine the Mycoplasma status of herds.

Analysis of Variance↗
PubMed1997

Tumorigenic transformation of immortalized ECV endothelial cells by cyclooxygenase-1 overexpression.

The cyclooxygenase (Cox) enzyme catalyzes the rate-limiting oxidative and peroxidative enzymatic steps in the biosynthesis of prostanoids. Both Cox-1 and -2 genes encode the two isoenzymes that carry out similar enzymatic steps. Enhanced Cox activity is associated with proliferative diseases such as colon cancer. To determine if a cause and effect relationship exists between Cox isoenzyme overexpression and tumorigenesis, the human Cox-1 and Cox-2 isoenzymes were transfected into ECV immortalized endothelial cells. Although numerous clones of Cox-1 expressing cells were obtained, Cox-2 overexpression resulted in growth disadvantage and increased cell death. In contrast, Cox-1 overexpressing cells expressed high levels of the functional Cox-1 polypeptide in the endoplasmic reticulum and the nucleus. In vitro proliferation of these cells was reduced compared with vector-transfected ECV cells. Cox-1 overexpression also enhanced the tumor necrosis factor-alpha-induced apoptosis of ECV cells 2-fold. In contrast to the in vitro behavior, ECV-Cox-1 cells proliferated aggressively and formed tumors in athymic "nude" mice, whereas the vector-transfected counterparts did not. The growth of Cox-1-induced tumors was not inhibited by indomethacin, suggesting a nonprostanoid function of Cox-1. ECV-Cox-1-derived tumors were angiosarcoma-like and contained numerous host-derived neovessels. These data suggest that Cox-1 overexpression in immortalized ECV endothelial cells results in nuclear localization of the polypeptide and tumorigenesis.

Animals↗
PubMed1997

Post-proliferative cyclin E-associated kinase activity in differentiated osteoblasts: inhibition by proliferating osteoblasts and osteosarcoma cells.

Spontaneous differentiation of normal diploid osteoblasts in culture is accompanied by increased cyclin E associated kinase activity on (1) the retinoblastoma susceptibility protein pRB, (2) the p107 RB related protein, and (3) two endogenous cyclin E-associated substrates of 78 and 105 kD. Activity of the differentiation-related cyclin E complexes (diff.ECx) is not recovered in cdc2 or cdk2 immunoprecipitates. Phosphorylation of both the 105 kD endogenous substrate and the p107 exogenous substrate is sensitive to inhibitory activity (diff.ECx-i) present in proliferating osteoblasts. This inhibitory activity is readily recruited by the cyclin E complexes of differentiated osteoblasts but is not found in cyclin E immunoprecipitates of the proliferating cells themselves. Strong inhibitory activity on diff.ECx kinase activity is excerted by proliferating ROS 17/2.8 osteosarcoma cells. However, unlike the normal diploid cells, the diff.ECx-i activity of proliferating ROS 17/2.8 cells is recovered by cyclin E immunoprecipitation. The cyclin-dependent kinase inhibitor p21CIP1/WAF1 inhibits diff.ECx kinase activity. Thus, our results suggest the existence of a unique regulatory system, possibly involving p21CIP1/WAF1, in which inhibitory activity residing in proliferating cells is preferentially targeted towards differentiation-related cyclin E-associated kinase activity.

Animals↗