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Biomedical subjects

E Schwarz

Publications and source records attributed to E Schwarz.

At least 91 records · Page 5Linked to original sources
PubMed1994

The Hong Kong adult oral health survey--1991: background, study population, and methods.

This second adult oral health survey was conducted with the following main aims: 1) to describe the oral health conditions and to analyse the oral health care needs and demands of 65-74-yr-olds in Hong Kong, and to propose appropriate strategies for meeting their needs in the light of societal obligations; 2) to describe the oral health conditions and to analyse the oral health care needs and demands of 35-44-yr-olds in Hong Kong with special emphasis on assessment of changes in this age group since 1984 (when the first adult oral health survey was conducted); 3) to assess the impact of sociodemographic and dental care system factors on the oral health status of selected adult age groups: and 4) to utilize survey data to refine curriculum development and research strategies in the Faculty of Dentistry, as well as in the proposal of appropriate action to governmental committees on dental health policy. For enhanced comparability with the previous study, the 35-44-yr-olds were selected from the same geographic areas of Hong Kong Island. Multistage cluster sampling was used to recruit the study population, defined geographic units and addresses being used as the starting-point. A sample of 398 subjects was selected, of whom 93% were both interviewed and clinically examined. The 65-74-yr-olds were recruited from housing estates in all principal areas of Hong Kong, yielding a sample of 559 subjects, of whom 96% were both interviewed and clinically examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Dental health knowledge and attitudes among the middle-aged and the elderly in Hong Kong.

Previous studies on adult Hong Kong Chinese have indicated that their level of knowledge of and attitudes toward dental health might be a potential barrier to effective oral preventive efforts. The knowledge and attitudes of elderly Chinese have not previously been studied. The objectives of this study were to describe Hong Kong adults' knowledge of the causes of the two main oral diseases, caries and periodontal disease, and possible preventive measures, and to analyse possible relationships between knowledge and attitudes and selected sociodemographic and utilization variables. Two populations aged 35-44 yr (n = 398) and 65-74 yr (n = 559) were selected for the study, which was conducted as structured interviews. A knowledge score was constructed from questions on caries and periodontal disease development and prevention. Attitudes were measured in the younger group by beliefs and evaluations of those beliefs according to the theory of reasoned action (the higher the score, the more positive the attitude). Knowledge scores were almost normally distributed in the younger respondents, but were heavily skewed toward 0 in the older group. In both age groups, increased level of education and regularity or recency of dental visits were strongly associated with dental knowledge. Women, regular dental care users, and prevention-oriented respondents had higher attitude scores. There was no correlation between knowledge and attitudes. Some improvement in knowledge seems to have taken place, especially on the cause of caries, with fewer 35-44-yr-old respondents claiming lack of knowledge of the causes of caries and gum disease than in a previous study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Chinese health beliefs and oral health practices among the middle-aged and the elderly in Hong Kong.

The purpose of this paper was to study possible relationships between traditional Chinese health beliefs and health practices in adult Chinese in a modernized society. The study populations comprised 398 35-44-yr-old and 559 65-74-yr-old Hong Kong Chinese. The respondents were categorized into three groups with weak, moderate, or strong Chinese beliefs on the basis of interview questions on the causes of gum disease. Chinese preventive practices and Chinese pain practices were defined according to respondents' reported use of recommended traditional cures. Questions on generally accepted oral practices were phrased in terms of frequency of daily brushing of teeth, use of toothpicks the previous day, and whether or not teeth were flossed the previous day. Around one-third of the respondents had weak, almost one-half had moderate, and around one-quarter expressed strong Chinese health beliefs. No significant differences in Chinese health beliefs were found between men and women in either age group, or between the age groups. In the 35-44 age group, more of those with a higher education were in the "weak" Chinese health belief category, whereas, conversely, more of those with a lower education expressed stronger Chinese health beliefs (P < 0.05). Women in both age groups reported significantly more frequent brushing. Toothpicks were used by around three-quarters of both age groups, but flossing was extremely rare.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Attitudes toward dentists and the dental care system among the middle-aged and the elderly in Hong Kong.

A sample of 398 35-44-yr-old and 559 65-74-yr-old Hong Kong Chinese were interviewed by trained interviewers using a structured questionnaire in an oral health survey conducted in 1991. The present analysis aimed to describe the dental-care-seeking behaviour and attitudes of these subjects. It was found that 43% of the younger and 23% of the older age group had visited a dentist within the past year. More than half of the elderly and a quarter of the adults had not been to a dentist for 3 yr or more, and the main reason given by these subjects was that they felt that nothing was wrong. The vast majority of the subjects consulted a dentist only when they had toothache or other dental problems. Less than 20% of the 35-44-yr-olds visited a dentist for a check-up or teeth cleaning, and these subjects were described as having a prevention-oriented attitude toward oral care. The result of a logistic regression analysis showed that there was a higher chance for subjects to have this attitude if they had dental programme coverage, perceived their teeth to be good, had better dental health knowledge, had a more positive dental attitude, and were less anxious about dental care. However, the influence of these factors was quite weak, because the overall percentage of correct classification of the model was 83.7% and the sensitivity was only 23.3%.

Adult↗
PubMed1994

Use of dental services by the middle-aged and the elderly in Hong Kong.

The objectives of this analysis were to describe the dental service use pattern of the 35-44- and 65-74-yr-old age groups and to determine to what extent this pattern could be explained by selected sociodemographic and attitudinal variables. The study populations comprised 398 35-44-yr-old and 559 65-74-yr-old Hong Kong Chinese. Use of dental services was determined on the basis of the respondents' own perception of the regularity of their dental visits and by the time since the last dental visit. The younger groups was categorized into regular users, irregular users, and nonusers, and the older group was categorized into three groups according to last dental visit (within 2 yr, 2-5-yr, 5 yr or more). A modification of the Andersen and Newman model for individual determinants of health care use was used as the framework for a logistic regression analysis. Predisposing variables were sex, education, occupation, attitudes, knowledge, preventive orientation, and dental anxiety; enabling variables were Family Possession Index, income, family support and access to a dental programme; need variables were perceived conditions of teeth, dental problems, dental pain, need for treatment, normative need for treatment, and denture wearing. In general, use of dental services was low. For the 35-44-yr-olds, the best regression model (sensitivity: 62%, specificity: 95%, overall correct classification: 88%) indicated that there was an increased probability of having a regular dental care pattern if respondents were prevention oriented, had access to a dental benefit programme, had not experienced pain, had a higher income, perceived their teeth as fair or poor, and perceived a need of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Tooth and root conditions in the middle-aged and the elderly in Hong Kong.

In an oral health survey of Hong Kong Chinese conducted in 1991, a sample of 372 35-44-yr-olds and 537 noninstitutionalized 65-74-yr-olds were interviewed and clinically examined. The examination procedures, instruments, and diagnostic criteria used to detect coronal caries followed those recommended by the World Health Organization (1987). The diagnostic criteria used to assess root-surface caries were based on those used in a national oral health survey of US employed adults (National Institute of Dental Research, 1987). Calibration of examiners was conducted before the survey and the interexaminer reliability was found to be very high; the kappa statistics were 0.93 and 0.91 for the younger and older age groups, respectively. None of the 35-44-yr-olds were edentulous and 96% had 21 teeth or more. The prevalence of edentulousness among the elderly was 12%. The DMFT indices of the younger and older age groups were 8.7 and 18.9, respectively. In both age groups, MT was the major component of the DMFT index, and female subjects had a slightly higher score. The prevalences of decayed/filled roots were 7% and 26% for the 35-44- and 65-74-yr-olds, respectively. As compared with previous surveys conducted in Hong Kong, there has been a 40% reduction in the DMFT index of the 35-44-yr-olds since 1968, but little change in the tooth and root conditions was noted between 1984 and 1991.

Adult↗
PubMed1993

Targeting of cytochrome b2 into the mitochondrial intermembrane space: specific recognition of the sorting signal.

UNLABELLED: Cytochrome b2 contains 2-fold targeting information: an amino-terminal signal for targeting to the mitochondrial matrix, followed by a second cleavable sorting signal that functions in directing the precursor into the mitochondrial intermembrane space. The role of the second sorting sequence was analyzed by replacing one, two or all of the three positively charged amino acid residues which are present at the amino-terminal side of the hydrophobic core by uncharged residues or an acidic residue. With a number of these mutant precursor proteins, processing to the mature form was reduced or completely abolished and at the same time targeting to the matrix space occurred. The accumulation in the matrix depended on a high level of intramitochondrial ATP. At low levels of matrix ATP, the mutant proteins were sorted into the intermembrane space like the wild-type precursors. THE RESULTS: (i) suggest the existence of one or more matrix components that specifically recognize the second sorting signal and thereby trigger the translocation into the intermembrane space; (ii) indicate that the mutant signals have reduced ability to interact with the recognition component(s) and then embark on the default pathway into the matrix by interacting with mitochondrial hsp70 in conjunction with matrix ATP; (iii) strongly argue against a mechanism by which the hydrophobic segment of the sorting sequence stops translocation in the hydrophobic phase of the inner membrane.

Adenosine Triphosphate↗
PubMed1993

Molecular cloning of integrin-associated protein: an immunoglobulin family member with multiple membrane-spanning domains implicated in alpha v beta 3-dependent ligand binding.

Integrin Associated Protein (IAP) is a 50-kD membrane protein which copurifies with the integrin alpha v beta 3 from placenta and coimmunoprecipitates with beta 3 from platelets. IAP also is functionally associated with signal transduction from the Leukocyte Response Integrin. Using tryptic peptide sequence, human and murine IAP cDNAs have been isolated. The protein has an extracellular amino-terminal immunoglobulin domain that binds all monoclonal anti-IAP antibodies. The carboxy-terminal region is highly hydrophobic with three or five membrane-spanning segments and a short hydrophilic tail. Immunofluorescence microscopy suggests that this hydrophilic tail is located on the inside of the cytoplasmic membrane. Monoclonal anti-IAP antibody inhibits the binding of vitronectin-coated beads to alpha v beta 3 on human erythroleukemia cells, and polyclonal anti-IAP recognizes hamster IAP on CHO cells and inhibits vitronectin bead binding. When CHO cells are transfected with human IAP, monoclonal anti-human antibody completely inhibits vitronectin bead binding. These data suggest a model in which ligand binding by alpha v beta 3 is regulated by IAP.

Amino Acid Sequence↗
PubMed1993

Improving oral health through understanding the meaning of health and disease in a Chinese culture.

Advances in modern technology have undoubtedly been of benefit to dentistry in its preventive and curative activities for populations worldwide. Studies, mainly from Western societies, show nonetheless that utilisation of services or adoption of preventive methods are not taken up at satisfactory levels. The focus of this paper is on the special problems in a Chinese society where major differences exist between the traditional lay health concepts and the modernised professional ones. Traditional Chinese health concepts comprise the balance between and interaction of 'Yin' and 'Yang', the vital forces in both the universe and in man's body, as the basis for maintaining health. To restore a disturbed equilibrium of vital forces, which will manifest itself as disease, a range of dietary products are available in Hong Kong, for example cooling herb tea to reduce fire from the stomach producing gum disease. Seeking dental treatment from dentists could be delayed or made 'unnecessary' due to reliance on home remedies. This could reduce the effectiveness of any planned health education activities and dental services available for improving the oral health status of the community according to prevailing Western concepts. An understanding of the cultural meaning of dental disease is fundamental to changing beliefs and attitudes of people in order to improve the oral health of the community.

Attitude to Health↗
PubMed1992

Nucleotide sequence and functional properties of a sodium-dependent citrate transport system from Klebsiella pneumoniae.

The gene of the sodium-dependent citrate transport system from Klebsiella pneumoniae (citS) is located on plasmid pES3 (Schwarz, E., and Oesterhelt, D. (1985) EMBO J. 4, 1599-1603) and encodes a 446-amino acid protein. Transport of citrate via this citrate transport protein (CitS) is dependent on the presence of sodium ions and is inhibited by magnesium ions. The delta pH (pH gradient across the membrane) is the major driving force for uptake. It is postulated that, in analogy with the proton-dependent citrate carrier (CitH) of K. pneumoniae (van der Rest, M. E., Abee, T., Molenaar, D., and Konings, W. N. (1990) Eur. J. Biochem. 195, 71-77), only one of the protonated species of citrate is recognized by CitS and that citrate is translocated across the membrane in symport with protons and sodium ions. The hydrophobicity profile of CitS suggests that the protein is very hydrophobic and contains 12 membrane-spanning segments. These segments are not centered around a hydrophilic core as has been suggested for other transport proteins, but the protein is asymmetrical with seven transmembrane segments in front of a large hydrophilic loop and five after this loop. The amino acid sequence is highly similar to a citrate transport system of Lactococcus lactis subsp. lactis var. diacetylactis (CitP) (David, S., van der Rest, M. E., Driessen, A. J. M., Simons, G., and de Vos, W. M. (1990) J. Bacteriol. 172, 5789-5794) and less similar to CitH of K. pneumoniae. We conclude that the citS gene of K. pneumoniae encodes a sodium-dependent citrate transport system that belongs to a novel subclass of transport proteins.

Amino Acid Sequence↗
PubMed1992

Retinoic acid-mediated repression of human papillomavirus 18 transcription and different ligand regulation of the retinoic acid receptor beta gene in non-tumorigenic and tumorigenic HeLa hybrid cells.

Human papillomavirus type 18 (HPV18) belongs to the group of genital papillomaviruses involved in the development of cervical carcinomas. Since retinoic acid (RA) is a key regulator of epithelial cell differentiation and a growth inhibitor in vitro of HPV18-positive HeLa cervical carcinoma cells, we have used HeLa and HeLa hybrid cells in order to analyse the effects of RA on expression of the HPV18 E6 and E7 oncogenes and of the cellular RA receptor genes RAR-beta and -gamma. We show here that RA down-regulates HPV18 mRNA levels apparently due to transcriptional repression. Transient cotransfection assays indicated that RARs negatively regulate the HPV18 upstream regulatory region and that the central enhancer can confer RA-dependent repression on a heterologous promoter. RA treatment resulted in induction of RAR-beta mRNA levels in non-tumorigenic HeLa hybrid cells, but not in tumorigenic hybrid segregants nor in HeLa cells. No alterations of the RAR-beta gene or of the HeLa RAR-beta promoter could be revealed by Southern and DNA sequence analysis, respectively. As determined by transient transfection assays, however, the RAR-beta control region was activated by RA more strongly in non-tumorigenic hybrid cells than in HeLa cells, thus indicating differences in trans-acting regulatory factors. Our data suggest that the RARs are potential negative regulators of HPV18 E6 and E7 gene expression, and that dysregulation of the RAR-beta gene either causatively contributes to or is an indicator of tumorigenicity in HeLa and HeLa hybrid cells.

Base Sequence↗
PubMed1992

The glucose kinase gene of Streptomyces coelicolor A3(2): its nucleotide sequence, transcriptional analysis and role in glucose repression.

Mutants (glk) of Streptomyces coelicolor A3(2) that are resistant to the non-utilizable glucose analogue 2-deoxyglucose are deficient in glucose kinase activity, defective in glucose repression, and usually unable to utilize glucose. A 2.9 kb BclI fragment, previously shown to restore a wild-type phenotype to a glk deletion mutant that lacks the entire segment, contains two complete open reading frames that would encode proteins of 20.1 kDa (ORF2) and 33.1 kDa (ORF3). ORF3 is transcribed from its own promoter, and also from a promoter that initiates transcription upstream of ORF2. A derivative of the temperate phage phi C31 containing ORF3 alone restored a wild-type phenotype when used to lysogenize the deletion mutant. The product of ORF3 is homologous to members of a family of repressor proteins encoded by xylR in Bacillus subtilis and Lactobacillus pentosus, and by nagC in Escherichia coli. Although this might suggest that ORF3 encodes a positive activator for glucose kinase, rather than the enzyme itself, ORF3 restored the ability to metabolize glucose to an E. coli glk mutant, and activity gels of cell extracts of E. coli containing ORF3 cloned in the pT7-7 expression vector demonstrated that the ORF3 product has glucose kinase activity.

Amino Acid Sequence↗
PubMed1991

Small-angle X-ray study on the quaternary structure of erythrocruorin from Caenestheria inopinata.

The erythrocruorin of the clam shrimp Caenestheria inopinata was studied in sodium phosphate buffer at pH 6.8 by small-angle X-ray scattering. The following molecular parameters were determined: radius of gyration 4.77 +/- 0.05 nm, maximum dimension 14.0 +/- 0.5 nm and a volume of 640 +/- 40 nm3. A model which fits the experimental data well is presented. The model is composed of 10 subunits arranged symmetrically in two layers, whereby five subunits are always forming a ring.

Animals↗
PubMed1991

Human papillomavirus type 18 E6*, E6, and E7 protein synthesis in cell-free translation systems and comparison of E6 and E7 in vitro translation products to proteins immunoprecipitated from human epithelial cells.

Expression of the E6 and E7 transforming genes of human papillomavirus type 18 (HPV18) occurs via structurally bicistronic mRNAs in which the downstream open reading frame (ORF) E7 is preceded either by the full-length ORF E6 or by a spliced ORF, E6*. We have used in vitro transcription and translation of HPV18 cDNAs in order to analyze the synthesis of E6*, E6, and E7 proteins and to compare the E6 and E7 in vitro translation products with the authentic proteins immunoprecipitated from cervical cancer cells. In wheat germ extract, in vitro translation resulted in the production of all three proteins, E6*, E6, and E7. In rabbit reticulocyte lysate, however, only the E6 and E7 proteins were produced. The lack of E6* protein was due neither to template RNA degradation nor to an inhibitory influence of the RNA 5' leader sequences, thus indicating the possibility of either inhibition of synthesis or degradation of E6* protein in reticulocyte lysate. The E7 protein was synthesized from both E6*-E7 and E6-E7 RNAs. In vitro-synthesized and authentic HPV18 E7 proteins revealed identical electrophoretic mobilities in two-dimensional gel electrophoresis, thus indicating similar modifications. By using a monoclonal antibody against the N terminus of HPV18 E6* and E6, an 18-kDa protein was detected not only in HPV18-positive but also in HPV18-negative epithelial cells. The 18-kDa proteins and the in vitro-synthesized HPV18 E6 protein exhibited comparable electrophoretic characteristics in two-dimensional gels. These results suggest the possible existence of a cellular protein related to HPV18 E6.

Cell-Free System↗
PubMed1991

The early genes E6 and E7 of cancer associated human papilloma viruses as targets of tumor suppression?

We have transplanted HPV 18 positive nontumorigenic hybrid cells and tumorigenic hybrid segregants as well as nontumorigenic and tumorigenic human keratinocytes immortalized by HPV 16-DNA transfection (HPK cells and HPK-ras cells) into nude mice and grown them under in vivo conditions for different periods of time. By analyzing gene expression at the mRNA level of the early viral genes E6/E7 and a number of cytoskeletal cellular genes we wanted to test the hypothesis that the nontumorigenic phenotype of these cells in vivo may be determined by the specific downregulation of expression of the oncogenic E6/E7 genes by the product(s) of tumor suppressor gene(s). The results obtained showed that: 1) The nontumorigenic hybrid cells (in contrast to tumorigenic segregants) stopped to proliferate about 3 days after transplantation. At this time E6/E7 gene expression was already drastically reduced, whereas at day 2 expression was still high. This suppression specifically affected the HPV 18 E6/E7 genes and preceded cell death by at least 10 days. 2) The same specific suppression of HPV E6/E7 gene expression occurred during in vivo growth of the nontumorigenic HPK cells. These cells gave rise to transiently growing cysts, but had retained the in vivo differentiation potential of normal keratinocytes (orderly expression of cytokeratins 1 and 10, involucrin and filaggrin). HPV 16 E6/E7 gene expression was very low and clearly restricted to a small subset of basal cells, thus showing an inverse relationship to terminal differentiation. In contrast, in the tumors induced by HPK-ras cells E6/E7 gene expression extended from the basal cells into suprabasal cells and terminal differentiation was retarded. These results support the hypothesis that during in vivo growth tumor suppressor gene(s) negatively regulated HPV E6/E7 gene expression resulting in the stop of proliferation of the nontumorigenic cells.

Animals↗