Interpreter-mediated dentistry.

The global movements of healthcare professionals and patient populations have increased the complexities of medical interactions at the point of service. This study examines interpreter mediated talk in cross-cultural general dentistry in Hong Kong where assisting para-professionals, in this case bilingual or multilingual Dental Surgery Assistants (DSAs), perform the dual capabilities of clinical assistant and interpreter. An initial language use survey was conducted with Polyclinic DSAs (n = 41) using a logbook approach to provide self-report data on language use in clinics. Frequencies of mean scores using a 10-point visual analogue scale (VAS) indicated that the majority of DSAs spoke mainly Cantonese in clinics and interpreted for postgraduates and professors. Conversation Analysis (CA) examined recipient design across a corpus (n = 23) of video-recorded review consultations between non-Cantonese speaking expatriate dentists and their Cantonese L1 patients. Three patterns of mediated interpreting indicated were: dentist designated expansions; dentist initiated interpretations; and assistant initiated interpretations to both the dentist and patient. The third, rather than being perceived as negative, was found to be framed either in response to patient difficulties or within the specific task routines of general dentistry. The findings illustrate trends in dentistry towards personalized care and patient empowerment as a reaction to product delivery approaches to patient management. Implications are indicated for both treatment adherence and the education of dental professionals.

Rapid and simultaneous detection of Mycobacterium tuberculosis complex and Beijing/W genotype in sputum by an optimized DNA extraction protocol and a novel multiplex real-time PCR.

Rapid diagnosis and genotyping of Mycobacterium tuberculosis by molecular methods are often limited by the amount and purity of DNA extracted from body fluids. In this study, we evaluated 12 DNA extraction methods and developed a highly sensitive protocol for mycobacterial DNA extraction directly from sputa using surface-coated magnetic particles. We have also developed a novel multiplex real-time PCR for simultaneous identification of M. tuberculosis complex and the Beijing/W genotype (a hypervirulent sublineage of M. tuberculosis) by using multiple fluorogenic probes targeting both the M. tuberculosis IS6110 and the Rv0927c-pstS3 intergenic region. With reference strains and clinical isolates, our real-time PCR accurately identified 20 non-Beijing/W and 20 Beijing/W M. tuberculosis strains from 17 different species of nontuberculosis Mycobacterium (NTM). Further assessment of our DNA extraction protocol and real-time PCR with 335 nonduplicate sputum specimens correctly identified all 74 M. tuberculosis culture-positive specimens. In addition, 15 culture-negative specimens from patients with confirmed tuberculosis were also identified. No cross-reactivity was detected with NTM specimens (n = 31). The detection limit of the assay is 10 M. tuberculosis bacilli, as determined by endpoint dilution analysis. In conclusion, an optimized DNA extraction protocol coupled with a novel multiprobe multiplex real-time PCR for the direct detection of M. tuberculosis, including Beijing/W M. tuberculosis, was found to confer high sensitivity and specificity. The combined procedure has the potential to compensate for the drawbacks of conventional mycobacterial culture in routine clinical laboratory setting, such as the lengthy incubation period and the limitation to viable organisms.

Genetic and phenotypic characterization of drug-resistant Mycobacterium tuberculosis isolates in Hong Kong.

OBJECTIVES: To characterize 250 drug-resistant Mycobacterium tuberculosis (MTB) isolates in Hong Kong with respect to their drug susceptibility phenotypes to five common anti-tuberculosis drugs (ofloxacin, rifampicin, ethambutol, isoniazid and pyrazinamide) and the relationship between such phenotypes and the patterns of genetic mutations in the corresponding resistance genes (gyrA, rpoB, embB, katG, inhA, ahpC and pncA). METHODS: The MIC values of the aforementioned anti-tuberculosis drugs were determined for each of the 250 drug-resistant MTB clinical isolates by the absolute concentration method. Genetic mutations in the corresponding resistance genes in these MTB isolates were identified by PCR-single-stranded conformation polymorphism/multiplex PCR amplimer conformation analysis (SSCP/MPAC), followed by DNA sequencing of the purified PCR products. RESULTS: Resistance to four or five drugs was commonly observed in these MTB isolates; such phenotypes accounted for over 34% of the 250 isolates. The most frequently observed phenotypes were those involving both rifampicin and isoniazid, with or without additional resistance to the other drugs. A total of 102 novel mutations, which accounted for 80% of all mutation types detected in the 7 resistance genes, were recovered. Correlation between phenotypic and mutational data showed that genetic changes in the gyrA, rpoB and katG genes were more consistently associated with a significant resistance phenotype. Despite this, however, a considerable proportion of resistant MTB isolates were found to harbour no detectable mutations in the corresponding gene loci. CONCLUSIONS: These findings expand the spectrum of potential resistance-related mutations in MTB clinical isolates and help consolidate the framework for the development of molecular methods for delineating the drug susceptibility profiles of MTB isolates in clinical laboratories.

High-level gentamicin resistance mediated by a Tn4001-like transposon in seven nonclonal hospital isolates of Streptococcus pasteurianus.

We report on the first occurrence of high-level gentamicin resistance (MICs > or = 512 microg/ml) in seven clinical isolates of Streptococcus pasteurianus from Hong Kong. These seven isolates were confirmed to be the species S. pasteurianus on the basis of nucleotide sequencing of the superoxide dismutase (sodA) gene. Epidemiological data as well as the results of pulse-field gel electrophoresis analysis suggested that the seven S. pasteurianus isolates did not belong to the same clone. Molecular characterization showed that they carried a chromosomal, transposon-borne resistance gene [aac(6')Ie-aph(2'')Ia] which was known to encode a bifunctional aminoglycoside-modifying enzyme. The genetic arrangement of this transposon was similar to that of Tn4001, a transposon previously recovered from Staphylococcus aureus and other gram-positive isolates. Genetic linkage with other resistance elements, such as the ermB gene for erythromycin resistance, was not evident. On the basis of these findings, we suggest that routine screening for high-level gentamicin resistance should be recommended for all clinically significant blood culture isolates. This is to avoid the inadvertent use of short-course combination therapy with penicillin and gentamicin, which may lead to the failure of treatment for endocarditis, the selection of drug-resistant Streptococcus pasteurianus and other gram-positive organisms, as well as the unnecessary usage of gentamicin, a drug with potential toxicity.

Chromosomal integration mechanism of infecting mu virion DNA.

DNA transposition is central to the propagation of temperate phage Mu. A long-standing problem in Mu biology has been the mechanism by which the linear genome of an infecting phage, which is linked at both ends to DNA acquired from a previous host, integrates into the new host chromosome. If Mu were to use its well-established cointegrate mechanism for integration (single-strand nicks at Mu ends, joined to a staggered double-strand break in the target), the flanking host sequences would remain linked to Mu; target-primed replication of the linear integrant would subsequently break the chromosome. The absence of evidence for chromosome breaks has led to speculation that infecting Mu might use a cut-and-paste mechanism, whereby Mu DNA is cut away from the flanking sequences prior to integration. In this study we have followed the fate of the flanking DNA during the time course of Mu infection. We have found that these sequences are still attached to Mu upon integration and that they disappear soon after. The data rule out a cut-and-paste mechanism and suggest that infecting Mu integrates to generate simple insertions by a variation of its established cointegrate mechanism in which, instead of a "nick, join, and replicate" pathway, it follows a "nick, join, and process" pathway. The results show similarities with human immunodeficiency virus integration and provide a unifying mechanism for development of Mu along either the lysogenic or lytic pathway.

True reversal of Mu integration.

We describe a high-temperature (75 degrees C) transition in the Mu integration complex that causes efficient and true reversal of the integration reaction. A second reversal pathway, first described as 'foldback' reversal for the HIV integrase, was also observed upon disassembly/reassembly of the Mu complex at normal temperatures. Both true and foldback reversal severed only one or the other of the two integrated Mu ends, and each exhibited distinct metal ion specificities. Our results directly implicate an altered transposase configuration in the Mu strand transfer complex that inhibits reversal, thereby regulating the directionality of transposition.

Inhibitory effects of antifungal proteins on human immunodeficiency virus type 1 reverse transcriptase, protease and integrase.

A variety of antifungal proteins were isolated from seeds of leguminous plants including French bean, cowpea, field bean, mung bean, peanut and red kidney bean. They were assayed for ability to inhibit human immunodeficiency virus type I (HIV-1) reverse transcriptase, protease and integrase, enzymes essential to the life cycle of HIV-1 . It was found that the cowpea beta-antifungal protein had a high potency in inhibiting HIV-1 protease and HIV-1 integrase. Cowpea alpha-antifungal protein was potent in inhibiting HIV-1 reverse transcriptase and HIV-1 integrase. Peanut antifungal protein was characterized by a high inhibitory activity against HIV-1 integrase and an intermediate potency in inhibiting HIV- I reverse transcriptase and HIV- I protease. French bean thaumatin-like protein expressed low HIV- I protease inhibitory activity and red kidney bean lectin inhibited HIV- I integrase by only a very small extent. Antifungal proteins from the field bean and mung bean had an intermediate potency in inhibitory HIV-1 protease and integrase. However, mung bean antifungal protein was not capable of inhibiting HIV-1 reverse transcriptase. The results indicate that nearly all leguminous antifungal proteins examined were able to inhibit HIV-1 reverse transcriptase, protease and integrase to some extent.

Inhibition of human immunodeficiency virus type 1 reverse transcriptase, protease and integrase by bovine milk proteins.

Different proteins have been isolated from bovine milk including lactoferrin, lactoperoxidase, glycolactin, angiogenin-1, lactogenin, alpha-lactalbumin, lactoglobulin and casein. These proteins have been assayed for inhibitory activity against human immunodeficiency virus type 1 (HIV-1) reverse transcriptase, protease and integrase, enzymes crucial to the HIV-1 life cycle. It was found that different milk proteins inhibited the three aforementioned HIV enzymes to different extents. Lactoferrin strongly inhibited HIV-1 reverse transcriptase but only slightly inhibited HIV-1 protease and integrase. On the other hand, alpha-lactalbumin, beta-lactoglobulin and casein inhibited HIV-1 protease and integrase to an appreciable extent but did not inhibit HIV-1 reverse transcriptase. Glycolactin and angiogenin-1 suppressed the activity of HIV-1 reverse transcriptase by a moderate extent but more powerfully inhibited HIV-1 protease and integrase. In comparison with the other milk proteins glycolactin was a strong inhibitor of HIV-1 protease and integrase and a moderate inhibitor of HIV-1 reverse transcriptase. Lactogenin was a strong inhibitor of HIV-1 integrase, a moderate inhibitor of HIV-1 reverse transcriptase and a weak inhibitor of HIV-1 protease.

A comparison of HIV-1 integrase inhibition by aqueous and methanol extracts of Chinese medicinal herbs.

The aqueous and methanol extracts of twenty herbs traditionally used in Chinese medicine were screened for anti-HIV-1 integrase activity in a non-radioactive ELISA-based HIV-1 integrase assay. The screening was performed at an herb extract concentration of 50 microg/ml. It was found that most of the aqueous and methanol herb extracts could elicit strong inhibition of HIV-I integrase activity. The inhibition was most likely due to tannins or polyphenolics in the herb extracts. In most of the herb extracts, 40-80% of the anti-HIV-1 integrase activity could be removed after passing through a minicolumn of polyamide resin. After removal of polyphenolic compounds, the methanol extract of Paeonia suffruticosa still exerted potent inhibition of HIV-1 integrase (EC50 = 15 microg/ml) and the aqueous extract of Prunella vulgaris caused moderate inhibition (EC50 = 45 microg/ml). The results support the view that herbs represent a rich source of anti-HIV compounds.

Helping mothers discuss sexuality and AIDS with adolescents.

The current study was designed to alter experimentally mothers' style when discussing sexuality and AIDS with their adolescent children. Mothers of 11- to 15-year-olds (N = 50) were assigned to an intervention or control group, resulting in 20 dyads in each group. All dyads were assessed twice, on self-reported and observed communication, AIDS knowledge, and perceived vulnerability to AIDS. Intervention group mothers received two training sessions. Observational data revealed that intervention group mothers reduced their amount of speaking, asked more open-ended questions, acted less judgmental, and discussed dating and sexuality more than did control group mothers. Intervention group adolescents reported increased discussions of birth control and increased daily comfort talking to their mothers. There was some evidence that intervention group girls increased in AIDS knowledge. There was no change in AIDS-related beliefs.

A comparison of human immunodeficiency virus type-1 protease inhibition activities by the aqueous and methanol extracts of Chinese medicinal herbs.

The aqueous and methanol extracts of thirty-one herbs traditionally used as anti-fever remedies in China were screened for their in vitro inhibition on human immunodeficiency virus type-1 protease (HIV-1 PR). The activity of recombinant HIV-1 protease was determined by sequence-specific cleavage at the Tyr-Pro bond of the fluorogenic substrate (Arg-Glu(EDANS)-Ser-Gln-Asn-Tyr-Pro-Ile-Val-Gln-Lys(DABCYL)- Arg) or by HPLC anaylsis of the cleavage products after incubation of the enzyme with a synthetic peptide substrate (Acetyl-Ser-Gln-Asn-Tyr-Pro-Val-Val-amide). Among the herbal extracts examined, the aqueous extracts of Prunella vulgaris and Scutellaria baicalensis and the methanol extracts of Woodwardia unigemmata, Paeonica suffruticosa and Spatholobus suberectus elicited significant inhibition (>90%) at a concentration of 200 microg/ml.

The biology of ophiobolins.

This review article aims at summarizing the research findings on the biological aspects of ophiobolins, phytotoxins produced by the pathogenic fungi Bipolaris species, which usually infect rice, maize and sorghum. The topics covered include the organisms that produce the various ophiobolins, the structural variations of ophiobolins, the biological actions of ophiobolins in plants, animals and microorganisms, and the mode of action and the possible use of ophiobolin A as a calmodulin antagonist.

How Latino American and European American adolescents discuss conflicts, sexuality, and AIDS with their mothers.

The authors examined how the structure of mother-adolescent conversations differs by ethnic group, age, and dyadic and individual factors. Mother-adolescent dyads of European or Latino descent participated in conversations and reported on their relationship and AIDS knowledge. Latina American mothers dominated conversations more than European American mothers, independent of socioeconomic status. Mothers dominated conversations about sexuality and AIDS more than conversations about conflicts. Mothers of older adolescents reacted more negatively, and older adolescents reported less satisfaction, less openness, and more sexual discussions with persons other than their mothers. Latino American adolescents whose mothers dominated conversations more reported fewer sexual discussions. Latina American mothers who dominated conversations more reported more openness and satisfaction. When mothers dominated conversations more, adolescents had lower AIDS knowledge.

The plant ribosome inactivating proteins luffin and saporin are potent inhibitors of HIV-1 integrase.

The ribosome inactivating proteins (RIPs) are a group of proteins that are able to inactivate eukaryotic protein synthesis by attacking the 28S ribosomal RNA. Recent studies have shown that some RIPs possess strong anti-human immunodeficiency virus (HIV) activity. In this study, several common plant RIPs including agrostin, gelonin, luffin, alpha-momorcharin, beta-momorcharin, saporin and trichosanthin were examined for the ability to interfere with HIV-1 replication in a variety of mechanistic assays in vitro. These assays included the CD4/gp120 interaction assay, HIV-1 reverse transcriptase (RT) assay, HIV-1 protease assay and HIV-1 integrase assay. At the concentration of 100 nM, all RIPs appeared to enhance the CD4/gp120 interaction by about 50%. These RIPs exhibited a very weak suppressive effect on HIV-1 RT and on HIV-1 protease. In contrast, with the exception of agrostin, all the RIPs tested could strongly inhibit HIV-1 integrase, the extent of inhibition ranging from 26.1 to 96.3% in an ELISA-based assay. Two RIPs, saporin and luffin, which licited over 90% inhibition in the ELISA-based assay, were further characterized in a radiometric assay. Both of these two RIPs evoked a strong dose-dependent inhibition in the 3'-end processing and strand-transfer activities of integrase. The results from this study suggest that the anti-HIV property of RIPs may be due to inhibition of HIV-1 integrase.

Initial kinetics of the inactivation of calmodulin by the fungal toxin ophiobolin A.

Ophiobolin A, a fungal toxin that affects rice and maize, inhibits calmodulin by reacting with the lysine residues in calmodulin. Previous studies have shown that lysines 75, 77 and 148 in the calmodulin molecule were the binding sites for ophiobolin A, and that lysine 75 was the primary inhibitory site. In this study, we used kinetic analysis and mutated calmodulins to further characterize the inhibition process. The inhibition of bovine-brain calmodulin by ophiobolin A in the presence of excess ophiobolin A occurred rapidly and followed pseudo-first-order kinetics with a second-order rate constant of 3470 M(-1) min(-1). The kinetics data indicated that the binding of a single ophiobolin A molecule was enough to inactivate a calmodulin molecule. Mutant calmodulins in which two of the three aforementioned binding sites for ophiobolin A had been removed by site-directed mutagenesis were examined for the role of each of the three lysines in the inhibition. It was found that when lysine 75 or 77 in the mutant calmodulin was reacted with ophiobolin A, the resulting calmodulin became a poor activator of phosphodiestease. These results provide further evidence that lysine 75 in calmodulin is the primary inhibitory site for ophiobolin A.

Radial nerve injury after intravenous cannulation at the wrist--a case report.

Peripheral venous cannulation is one of the commonest procedures performed in hospitals. The dorso-lateral aspect of the wrist is one of the favourite sites. Radial nerve injury, though extremely rare, can be a serious complication and has been reported twice. One patient was left with a permanent work disability due to a painful neuroma. Another patient required surgical intervention to remove a neuroma six months after the initial venous cannulation resulting in almost complete recovery. We report the first case of injury to the radial nerve at the wrist as a complication of venous cannulation where complete recovery occurred spontaneously. In our case, immediate removal of the cannula may be responsible for the improved outcome.

A longitudinal study of AIDS conversations between mothers and adolescents.

The current study examined the stability of mother-adolescent AIDS conversations. Twenty-four mother-adolescent dyads (9 boys, 15 girls) participated at Time 1 (adolescents aged 10-14 years), and again 2 years later. Mothers and adolescents engaged in a videotaped conversation about AIDS and completed AIDS questionnaires. Conversations were coded for content and the extent to which mothers dominated conversations. Conversational dominance remained stable over time. AIDS knowledge was greater for mothers than adolescents, but it improved over time for adolescents while remaining stable for mothers. Mothers who reported discussing AIDS-related topics with their adolescents had less discrepancy between their own and their children's AIDS knowledge. Conversational dominance at Time 1 predicted discrepancy in AIDS knowledge 2 years later, whereas discrepancy in AIDS knowledge at Time 1 did not predict conversational dominance two years later. These results suggest the importance of interactive conversations as a more effective way of teaching than didactic conversations.

What word learners do when input contradicts the mutual exclusivity assumption.

In 4 studies, 3- to 5-year-olds heard 2 novel English labels each applied to the same novel object by a different adult. In all 4 studies, about half of the children accepted both labels, suggesting that hearing 2 labels applied to an object offers strong enough evidence for some to override mutual exclusivity. Nonetheless, about half of the children honored mutual exclusivity and hence accepted only 1 label; they also seemed to keep both labels in mind for at least a few minutes and settled on whichever label they re-encountered first. This strategy allows children to make an informed choice between 2 apparently equally good labels, without straining their limited memory capacities.

Pituitary adenylate cyclase activating polypeptide is a potent calmodulin inhibitor.

We report here that pituitary adenylate cyclase activating polypeptide (PACAP38), a new 38-residue neuropeptide of the secretin/glucagon family, is a potent inhibitor of calmodulin in vitro in the activation of bovine brain calmodulin-dependent cyclic nucleotide phosphodiesterase. The concentration of PACAP38 for half-maximal inhibition of the phosphodiesterase is 15 nM, one of the lowest for known calmodulin inhibitors. In the presence of Ca2+, PACAP38 binds strongly to calmodulin in a 1:1 ratio with a dissociation constant of about 28 nM. The binding is not dissociated by 4 M urea. In the absence of Ca2+ the binding is at random and can be dissociated by 4 M urea. Studies with PACAP38 derivatives show that the carboxyl half of the PACAP38 molecule is essential for the inhibition of calmodulin.