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Biomedical subjects

E Schwarz

Publications and source records attributed to E Schwarz.

At least 37 records · Page 2Linked to original sources
PubMed2001

An Oral Health Survey in Southern China, 1997: background and methodology.

Relatively limited information is available about the oral health in the Guangdong Province of Southern China, the closest neighbor to Hong Kong. The study intended to explore the oral health status, knowledge, attitudes, and dental care utilization in the Guangdong population as a basis for formulating strategies for oral health prevention and treatment. Through multi-stage stratified and quota-sampling, individuals from urban as well as rural communities were selected (5- to 6-; 12-; 35- to 44-; and 65- to 74-year-olds; total N = 6251). Structured interviews and clinical examinations were performed. Inter-examiner reliability was high (kappa = 0.60-0.96). Samples of community water were taken for fluoride assessment. Overall, the sample surveyed was acceptably representative of the population, with some under-representation of rural residents and agricultural workers. Re-weighting was performed in appropriate analyses. The data analysis model used in the Second International Collaborative Study was used as a guide for the present data analysis. This approach has not previously been used on a Mainland Chinese population.

Adolescent↗
PubMed2001

Oral health status and oral health behaviors in Chinese Children.

The objectives of the study were to describe the oral health status and treatment needs of the 5- to 6-year-old and 12-year-old children in Southern China; to describe the patterns of oral health behaviors, knowledge, and attitudes among the 12-year-olds; and to assess the effects of socio-behavioral factors on the 12-year-old children's dental caries experiences. The study sample was comprised of 1,587 5- to 6-year-old and 1,576 12-year-old urban and rural schoolchildren living in Guangdong Province. Three calibrated dentists clinically examined the children, and trained interviewers interviewed the 12-year-olds. Caries prevalence of the 5- to 6-year-old children was high (urban 78% vs. rural 86%); the mean dmft of the urban and rural children was 4.8 and 7.0, respectively. The caries prevalence and mean DMFT score of the 12-year-olds were 41% and 0.9 (urban) and 42% and 0.9 (rural). Only 2% of the 12-year-olds exhibited no calculus or gingival bleeding, while more than 70% had calculus. In conclusion, there is an urgent need for establishing caries-preventive activities for preschool children. The prevalence of caries among the 12-year-olds was not high, but their periodontal condition was unsatisfactory. Knowledge about gum bleeding and the use of fluoride was low. More oral health education activities should be organized, especially for the rural children.

Analysis of Variance↗
PubMed2001

Utilization of dental services in Southern China.

A population's utilization of dental services is an important parameter in oral health care planning, which has rarely been studied in China. The objectives of this report were to describe the dental service utilization pattern of middle-aged and elderly Chinese and to analyze the influence of selected variables on the use of dental services. A Guangdong Province population of 1,573 35- to 44-year-olds and 1,515 65- to 74-year-olds recruited from urban and rural communities was interviewed in their local dialect. It was found that 23% of the middle-aged and 24% of the elderly subjects had visited a dentist within the preceding year. The two most commonly cited reasons for not having seen a dentist for at least 3 years were: no perceived need, and no serious dental problems. Among subjects who had visited a dentist within 3 years, the 3 most commonly received treatments were: fillings, extractions, and dental prostheses. Furthermore, a logistic regression analysis showed that women, subjects who lived in urban areas, were better educated, were wealthier, and had better oral health knowledge were more likely to be a recent dental service user. In conclusion, dental service utilization among the adult Southern Chinese was found to be low, problem-driven, and influenced by some socio-economic factors.

Adult↗
PubMed2001

Coronal and root caries in Southern Chinese adults.

Southern China is the most prosperous part of China, but information useful for oral care planning is very limited. A large-scale epidemiological survey was conducted in 1996-97. The objectives of this report were to describe the coronal and root caries of the adult Southern Chinese and to analyze the influence of selected demographic and socio-economic factors on the disease pattern. A total sample of 1,573 35- to 44-year-olds and 1,515 65- to 74-year-olds from 8 urban and 8 rural survey sites in Guangdong Province participated in an oral health interview and underwent clinical examination. World Health Organization examination procedures and diagnostic criteria were used. The weighted mean DMFT scores of the middle-aged and the elderly subjects were 4.8 and 16.1, respectively. People living in rural areas had a higher DMFT score than those living in urban areas (4.9 vs. 4.3 in the 35- to 44-year-olds and 16.5 vs. 14.7 in the 65- to 74-year-olds). In both age groups, MT was the major component of the DMFT score. Analysis of covariance showed that women and those who were economically less well off had higher DMFT scores in both age groups. The weighted prevalence rates of decayed/filled roots were 12% and 37%, with a mean of 0.2 and 0.7 teeth affected, in the middle-aged and the elderly, respectively. In conclusion, socio-economic factors had a considerable effect on the dental caries status of adults in Southern China.

Adult↗
PubMed2000

Growth inhibition of cervical cancer cells by the human retinoic acid receptor beta gene.

Transcription of the retinoic receptor beta (RARbeta) gene is activated in a ligand-dependent manner by the retinoic acid receptor alpha. Reduced RARbeta gene expression and loss of ligand inducibility are frequently observed in human carcinoma cells indicating that such alterations might contribute to carcinogenesis. In this study we have analyzed the influence of RARbeta on cervical cancer cell growth. Transfection of HeLa cells with RARbeta expression plasmids resulted in reduced clonal cell growth in the presence of retinoic acid (RA). RA-induced growth inhibition in HeLa x fibroblast hybrid cells was partially relieved by a dominant-negative RARbeta mutant. HeLa clones stably expressing a RARbeta transgene under control of the human beta-actin promoter [HeLa(RARbeta)] were established and analyzed for transgene-mediated growth alterations in vitro and in vivo. Anchorage-independent growth of the HeLa(RARbeta) lines was indistinguishable from that of control cells in the absence of RA, but strongly impaired after RA treatment. Reduced tumor growth of HeLa(RARbeta) clones was associated with high RARbeta protein levels. Somatic cell fusion experiments revealed that the loss of ligand inducibility of RARbeta gene expression in HeLa cells cannot be complemented by fusion with other cervical cancer cell lines. Our data indicate, firstly, that RARbeta is a negative regulator of tumor cell growth and, secondly, that cancer-associated defects in RARbeta gene expression are caused by stable, non-complementable silencing mechanisms.

Animals↗
PubMed2000

Influence of the menstrual cycle on the LPS-induced cytokine response of monocytes.

We previously observed a gender difference in the cytokine response of peripheral blood monocytes (PBM). The study was performed to find out whether the gender-related difference might be due to hormonal changes during the menstrual cycle in healthy premenopausal females. The release of tumour necrosis factor a (TNF-alpha) was reduced in the premenopausal females during the luteal phase compared to the follicular phase. Compared to the male controls the release of TNF-alpha and of interleukin 6 (IL-6) during the luteal phase was also diminished. In premenopausal females the concentration of estradiol in plasma correlated with the release of TNF-alpha and IL-6 during the luteal phase.

Adult↗
PubMed2000

Functional specificity of the mitochondrial DnaJ protein, Mdj1p, in Saccharomyces cerevisiae.

Inactivation of the gene for the mitochondrial DnaJ homolog, Mdj1p, in Saccharomyces cerevisiae results in temperature sensitivity and the loss of respiratory activity; the latter phenotype has been attributed to the loss of mitochondrial DNA. To investigate the functional specificity of Mdj1p, non-mitochondrial DnaJ proteins were targeted to mitochondria and tested for their ability to substitute for Mdj1p. The tested DnaJ proteins were able to complement the two Mdj1p-linked phenotypes, i.e., respiratory activity and growth at 37 degrees C, to different extents, ranging from full to very poor complementation. All DnaJ homologs ensured faithful propagation of the mitochondrial genome. N-terminal fragments of Mdjlp and Escherichia coli DnaJ comprising the well-characterized J domain partially substituted for Mdj1p. As the only hitherto known function of the N-terminal fragment is modulation of the substrate binding activity of the cognate Hsp70, we conclude that both Mdj1p-linked phenotypes - maintenance of respiratory activity and the ability to grow at elevated temperature - involve a mitochondrial Hsp70 partner protein.

Coloring Agents↗
PubMed2000

[Tracheobronchial foreign bodies].

Forty cases of children with an inhaled foreign body (FB) are reviewed over a three-year period. Clinical data, radiologic findings and complications are detailed. The nature and size of FBs are also reported. Diagnosis and management are discussed according to the most recent studies in the literature. Diagnostic flexible bronchoscopy is a useful first step when the diagnosis is unclear (i.e., choking history, unexplained respiratory symptoms), but FB removal is usually not possible during this procedure. Extraction is performed via the rigid bronchoscope under general anesthesia. However, FB could be removed with the flexible bronchoscope in five children in our study. Diagnosis and removal of an inhaled FB are required as quickly as possible in order to prevent respiratory sequelae (bronchiectasis). Prevention is based upon information to be given to families, but to the medical community as well, which often minimizes the seriousness of inhalation hazards.

Bronchi↗
PubMed2000

A dibasic motif in the tail of a class XIV apicomplexan myosin is an essential determinant of plasma membrane localization.

Obligate intracellular parasites of the phylum Apicomplexa exhibit gliding motility, a unique form of substrate-dependent locomotion essential for host cell invasion and shown to involve the parasite actin cytoskeleton and myosin motor(s). Toxoplasma gondii has been shown to express three class XIV myosins, TgM-A, -B, and -C. We identified an additional such myosin, TgM-D, and completed the sequences of a related Plasmodium falciparum myosin, PfM-A. Despite divergent structural features, TgM-A purified from parasites bound actin in an ATP-dependent manner. Isoform-specific antibodies revealed that TgM-A and recombinant mycTgM-A were localized right beneath the plasma membrane, and subcellular fractionation indicated a tight membrane association. Recombinant TgM-D also had a peripheral although not as sharply defined localization. Truncation of their respective tail domains abolished peripheral localization and tight membrane association. Conversely, fusion of the tails to green fluorescent protein (GFP) was sufficient to confer plasma membrane localization and sedimentability. The peripheral localization of TgM-A and of the GFP-tail fusion did not depend on an intact F-actin cytoskeleton, and the GFP chimera did not localize to the plasma membrane of HeLa cells. Finally, we showed that the specific localization determinants were in the very C terminus of the TgM-A tail, and site-directed mutagenesis revealed two essential arginine residues. We discuss the evidence for a proteinaceous plasma membrane receptor and the implications for the invasion process.

Actins↗
PubMed1999

DNA plasmid that codes for human Bcl-2 gene preserves axotomized Clarke's nucleus neurons and reduces atrophy after spinal cord hemisection in adult rats.

Spinal cord injury in adult mammals causes atrophy or death of some axotomized neurons. The product of the antiapoptotic gene Bcl-2 prevents neuron death in vivo. We delivered Bcl-2 by intraspinal injection of a DNA plasmid encoding this gene to determine if axotomized neurons destined to undergo retrograde death could be rescued. Axons of the right side Clarke's Nucleus (CN) were cut unilaterally in adult Sprague-Dawley rats by T8 hemisection, leaving the contralateral (left) CN as an intact control. Two months postoperatively, there was approximately 35% loss of total CN neurons in the right L1 segment. Only 15% of large CN neurons (>400 microm2), whose axons project to the cerebellum, survived--indicating atrophy and/or death of 85% of these cells. We injected a DNA plasmid encoding the human Bcl-2 gene and the bacterial reporter gene LacZ, which was complexed with cationic lipids, into the right side of segment T8 of the normal spinal cord, or just caudal to the hemisection site. The reporter gene was expressed in the perikarya of right CN neurons at L1 for up to 7 days, but not 14 days. Two months following T8 hemisection and Bcl-2/LacZ DNA injection, there was no significant loss of CN neurons ipsilateral to the lesion. Surprisingly, 61% of large neurons survived, indicating partial protection from atrophy. In contrast, a DNA plasmid that codes for the LacZ reporter gene, but not Bcl-2, did not prevent CN neuron death or atrophy. Administration of the Bcl-2 gene in adult rats and its expression in these CNS neurons prevents retrograde cell death, and also minimizes atrophy. These results may serve as the basis for developing novel gene therapy strategies for patients with spinal cord injury.

Animals↗
PubMed1999

Oral health status of southern Chinese following head and neck irradiation therapy for nasopharyngeal carcinoma.

OBJECTIVE: To investigate the oral health status of patients with nasopharyngeal carcinoma (NPC) after completion of radiotherapy. METHODS: Thirty-three NPC patients (mean age 53 +/- 10 years) who had completed head and neck radiotherapy (3.6 +/- 3.1 years post-operation) were examined. Dental caries, periodontal status and oral mucosal lesions were recorded. Stimulated whole saliva (SWS) flow rate, pH, buffer capacity and carriage rate of carcinogenic micro-organisms were assessed. Jaw opening was measured. RESULTS: Xerostomia was present in all patients, while 42% had candidiasis and 21% had limited jaw opening. The mean number of teeth present was 22, mean DMFT was 8.0, mean number of untreated root caries lesions was 1.4. Both saliva pH and buffering capacity were low while Streptococcus mutans and Lactobacillus spp. carriage were high. 52% of the patients had no dental care following radiotherapy. Although few patients expressed direct dissatisfaction, perceived level of information and of post-operative dental care was insufficient. CONCLUSIONS: Post-irradiated NPC patients constitute a high-risk group for dental root caries and oral candidiasis. The carriage rate of Streptococcus mutans and Lactobacillus spp. in this NPC patient group was the highest among findings of other similar studies. This may be related to the inadequacy of dental care after radiotherapy. Head and neck radiotherapy was not associated with periodontal disease.

Adult↗
PubMed1999

Dual role of the mitochondrial chaperone Mdj1p in inheritance of mitochondrial DNA in yeast.

Mdj1p, a homolog of the bacterial DnaJ chaperone protein, plays an essential role in the biogenesis of functional mitochondria in the yeast Saccharomyces cerevisiae. We analyzed the role of Mdj1p in the inheritance of mitochondrial DNA (mtDNA). Mitochondrial genomes were rapidly lost in a temperature-sensitive mdj1 mutant under nonpermissive conditions. The activity of mtDNA polymerase was severely reduced in the absence of functional Mdj1p at a nonpermissive temperature, demonstrating the dependence of the enzyme on Mdj1p. At a permissive temperature, the activity of mtDNA polymerase was not affected by the absence of Mdj1p. However, under these conditions, intact [rho(+)] genomes were rapidly converted to nonfunctional [rho(-)] genomes which were stably propagated in an mdj1 deletion strain. We propose that mtDNA polymerase depends on Mdj1p as a chaperone in order to acquire and/or maintain an active conformation at an elevated temperature. In addition, Mdj1p is required for the inheritance of intact mitochondrial genomes at a temperature supporting optimal growth; this second function appears to be unrelated to the function of Mdj1p in maintaining mtDNA polymerase activity.

DNA, Fungal↗
PubMed1998

Mam33p, an oligomeric, acidic protein in the mitochondrial matrix of Saccharomyces cerevisiae is related to the human complement receptor gC1q-R.

Mam33p (mitochondrial acidic matrix protein) is a soluble protein, located in mitochondria of Saccharomyces cerevisiae. It is synthesized as a precursor with an N-terminal mitochondrial targeting sequence that is processed on import. Mam33p assembles to a homo-oligomeric complex in the mitochondrial matrix. It can bind to the sorting signal of cytochrome b2 that directs this protein into the intermembrane space. Mam33p is encoded by an 801 bp open reading frame. Gene disruption did not result in a significant growth defect. Mam33p exhibits sequence similarity to gC1q-R, a human protein that has been implicated in the binding of complement factor C1q and kininogen.

Amino Acid Sequence↗
PubMed1998

APM-1, a novel human gene, identified by aberrant co-transcription with papillomavirus oncogenes in a cervical carcinoma cell line, encodes a BTB/POZ-zinc finger protein with growth inhibitory activity.

Integration of human papillomavirus (HPV) DNA into the host cell genome is an important step in cervical carcinogenesis. In tumour cells with integrated HPV DNA, transcription of viral oncogenes E6 and E7 continues into the flanking cellular sequences thereby producing viral-cellular fusion transcripts. Analysis of cellular sequences flanking the integrated HPV68 DNA in the cervical carcinoma cell line ME180 revealed homozygosity of the mutant allele in ME180 cells. We speculated that this could indicate the existence of a cellular tumour suppressor gene in the integration region. We report here the identification of a novel human gene, named APM-1, which is co-transcribed with the HPV68 E6 and E7 genes and is present in the 3'-cellular part of the ME180 viral-cellular fusion transcripts. The APM-1 gene encodes a protein with a BTB/POZ domain and four zinc fingers, and is located at chromosome 18q21. APM-1 transcripts are detected in normal cervical keratinocytes, but not in the majority of cervical carcinoma cell lines analysed. The APM-1 gene caused a reduction of clonal cell growth in vitro of HeLa and CaSki tumour cells. These characteristics make APM-1, the first novel human gene identified in a HPV integration region, a likely candidate for the postulated tumour suppressor gene.

Alleles↗