Pemphigus foliaceus in a patient with gastrointestinal stromal tumor treated with adjuvant imatinib mesylate

Pemphigus is an autoimmune bullous disease with a number of described associations, including medications, which have been grouped into three structural categories - thiol drugs, phenol drugs, and drugs with neither functional group [1]. Discontinuation of the offending medication is considered a mainstay of therapy. We report a patient in whom the onset of pemphigus foliaceus was associated with initiation of imatinib mesylate adjuvant therapy in a patient with resected gastrointestinal stromal tumor (GIST). Imatinib was continued because of the survival benefit to the patient with a resected, high risk GIST. Treatment with rituximab resulted in near resolution of his blistering rash and follow up enzyme-linked immunosorbent assay (ELISA) demonstrated reference range immunoreactivity for both desmoglein 1 and desmoglein 3. After dose increase of imatinib therapy owing to tumor growth, the patient subsequently again developed a similar eruption. Re-biopsy and ELISA were consistent with recurrence of pemphigus. In conclusion, although the patient's pemphigus was cleared with a single cycle of rituximab infusions while continuing imatinib therapy, the disease returned after imatinib dose was increased a year later, suggesting a dose-response relationship.

Neutrophil-predominant bullous pemphigoid induced by checkpoint inhibitors: A case series

Checkpoint inhibitors have been revolutionary in the treatment of metastatic melanoma, non-small-cell lung cancer, and renal cell carcinoma. By restricting negative feedback of T-cells, checkpoint inhibitors allow the immune system to identify and destroy malignant cells. This enhanced immune response is efficacious in the treatment of the aforementioned malignancies; however, it may lead to immune-related adverse events. Bullous pemphigoid (BP) is a well-documented cutaneous adverse reaction of checkpoint inhibitors, with a majority of cases reporting an eosinophil-predominant or mixed inflammatory infiltrate. We report two cases of neutrophil-predominant BP presenting in patients on checkpoint inhibitors.

5,6,7,8-Tetrahydro-1,6-naphthyridine Derivatives as Potent HIV-1-Integrase-Allosteric-Site Inhibitors

A series of 5,6,7,8-tetrahydro-1,6-naphthyridine derivatives targeting the allosteric lens-epithelium-derived-growth-factor-p75 (LEDGF/p75)-binding site on HIV-1 integrase, an attractive target for antiviral chemotherapy, was prepared and screened for activity against HIV-1 infection in cell culture. Small molecules that bind within the LEDGF/p75-binding site promote aberrant multimerization of the integrase enzyme and are of significant interest as HIV-1-replication inhibitors. Structure-activity-relationship studies and rat pharmacokinetic studies of lead compounds are presented.

Overuse of Magnetic Resonance Imaging in the Diagnosis and Treatment of Moderate to Severe Osteoarthritis

BACKGROUND

MRI in the evaluation of end-stage knee joint osteoarthritis (OA) is usually unnecessary when radiographic and clinical evidence of gonarthrosis is clear. The purpose of this study was to assess the prevalence of MRI scans ordered in patients with radiographically obvious gonarthrosis and to examine the characteristics of health care providers who ordered these imaging studies.

METHODS

We retrospectively identified 164 patients diagnosed with moderate to severe OA who were referred for total knee replacement (TKA) over a one-year period. The percentage of patients who had an MRI scan with or without X-ray, within the preceding 3 months prior to referral, were calculated. Subgroups were analyzed to identify characteristics that may influence the decision to order an MRI, including K-L grade, provider type, level of training, and practice location.

RESULTS

Of 145 patients, 19 (13.1%) presented with an MRI scan. Between the number of MRI scans ordered, there was a significant difference when comparing physicians versus non-physicians, with physicians ordering less MRI scans (p=0.018). There was a significant difference when comparing non-academic versus academic, with academic providers ordering less MRI scans (p=0.044). There was no significant difference with fellowship training or provider proximity to our academic institution.

CONCLUSIONS

In this study, 13.1% of patients with radiographically obvious knee OA obtained an MRI prior to referral for TKA. Non-physicians and non-academic physicians were more likely to order MRI scans. Improved education for referring providers may be necessary to decrease overuse of MRI in the diagnosis of moderate to severe arthritis.

LEVEL OF EVIDENCE

Level II.

Channel Gating Regulation by the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) First Cytosolic Loop

In this study, we present data indicating a robust and specific domain interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) first cytosolic loop (CL1) and nucleotide binding domain 1 (NBD1) that allows ion transport to proceed in a regulated fashion. We used co-precipitation and ELISA to establish the molecular contact and showed that binding kinetics were not altered by the common clinical mutation F508del. Both intrinsic ATPase activity and CFTR channel gating were inhibited severely by CL1 peptide, suggesting that NBD1/CL1 binding is a crucial requirement for ATP hydrolysis and channel function. In addition to cystic fibrosis, CFTR dysregulation has been implicated in the pathogenesis of prevalent diseases such as chronic obstructive pulmonary disease, acquired rhinosinusitis, pancreatitis, and lethal secretory diarrhea (e.g. cholera). On the basis of clinical relevance of the CFTR as a therapeutic target, a cell-free drug screen was established to identify modulators of NBD1/CL1 channel activity independent of F508del CFTR and pharmacologic rescue. Our findings support a targetable mechanism of CFTR regulation in which conformational changes in the NBDs cause reorientation of transmembrane domains via interactions with CL1 and result in channel gating.

Effect of dietary marine lipids on female white bass ova compositions and progeny survival

We evaluated white bass ovum fatty acid composition as well as embryonic and larval survival after varying n-3 and n-6 long-chain polyunsaturated fatty acid (LC-PUFA) concentrations in maternal diets. Diets containing graded levels (0, 33, 66, or 100%) of squid to menhaden oils were fed daily to apparent satiation to female white bass for 8 weeks prior to spawning. Embryonic survival was negatively related to maternal squid oil intake (P=0.015, R2=0.970). Squid oil-fed broodstock produced ova with decreased 20:5n-3 and increased C18 polyunsaturated fatty acid concentrations, largely reflecting the fatty acid profile of squid oil. Within ovum phospholipid, accumulation of 18:2n-6 may have altered biological function resulting in the lower embryonic survival among ova produced from the squid oil-fed broodstock. Our data suggest the importance of feeding white bass broodstock diets high in total n-3 LC-PUFA (at least 4.0% dry matter), and 20:5n-3-rich lipid sources such as menhaden oil can be effectively utilized by female white bass to produce quality ova.

Factors associated with pregnancies among HIV-positive women in a prevention of mother-to-child transmission programme

OBJECTIVE

This study identified factors contributing to pregnancies in HIV-positive women who were on a prevention of HIV from mother-to-child transmission (PMTCT) programme in Letlhakeng Subdistrict, Botswana.

METHOD

A cross-sectional descriptive survey was employed using an interviewer administered (face-to-face) questionnaire to obtain information from 35 HIV-positive pregnant women registered for a PMTCT programme. Use was made of a non-probability sampling method to obtain information from all the pregnant women who sought antenatal care (ANC) during the survey period.

RESULTS

The age of the participants ranged between 18 and 37 years with a modal age of 30 years and a mean of 29.02 years (standard deviation of 5.29). The majority of the participants were single (66%) and had two or more children (74%). About half of the participants (49%) had secondary school education and a high proportion of them knew their HIV-positive status for more than one year prior to the interview day (77%) while the same number of them were unemployed. Pregnant participants seemed to know their HIV status prior to pregnancy. Sharing information about the HIV status of their partners and the participant's financial dependence on their partners did not show any significant association with their pregnancy status. However the partner's desire for parenthood (p < 0.05, 95% CI), the age difference between them and their partners (p < 0.05, 95%CI) and the use of condoms (p < 0.05, 95% CI) indicated significant associations between decision-making and the pregnancies.

CONCLUSION

Pregnancy is common among HIV-positive women who are on a PMTCT at Letlhakeng sub-district as was shown by this study and this may constitute a serious health risk to the child and to the population in general.

STUDIES ON EXPERIMENTAL HYPERTENSION : XX. THE BIOASSAY OF RENIN

A simple, rapid method for the bioassay of renin has been presented. Reliable and consistent results are obtained by this method whereby an arbitrary dog unit of renin has been established. The response of normal unanesthetized dogs to renin is independent of the body weight of dogs weighing between 10 and 25 kilos. An estimate of potency of renin per kilo of body weight of the test animals is therefore not only unnecessary but misleading. A dog unit of renin has been defined as that amount which raises the blood pressure at least 30 and not more than 35 mm. Hg within 3 minutes in at least three unanesthetized dogs. The potency is expressed as dog units of renin per cubic centimeter. The determination of the amount of renal substance represented by a cubic centimeter of extract and the number of dog units per cubic centimeter give an estimate of the yield of renin which can be expressed as dog units of renin per gram of original renal tissue. By determination of the number of dog units per cubic centimeter and the amount of nitrogen in milligrams per cubic centimeter in any renal extract the purity of the renin can be determined and expressed as dog units of renin per milligram N. The establishment of a standard method for the bioassay of renin is considered highly desirable and the method outlined in this paper is suggested for this purpose.

STUDIES ON EXPERIMENTAL HYPERTENSION : XIX. THE PRODUCTION OF PERSISTENT HYPERTENSION IN SHEEP AND GOATS

Persistent hypertension has been produced in the goat and sheep by constriction of the main renal arteries. The presence or absence of accompanying uremia depends upon the degree of constriction of the renal arteries. In both sheep and goat, constriction of one main renal artery also caused elevation of the blood pressure which tended to persist longer than in the dog. Excision of the one kidney with main renal artery constricted resulted in a prompt (24 hours) return of the blood pressure to normal. In the animals with hypertension of long duration but without renal excretory insufficiency, (the "benign" phase) no significant arterio- or arteriolosclerosis developed as a result of the hypertension alone. In the animals that had both hypertension and renal excretory insufficiency, (the "malignant" phase) the typical terminal arteriolar lesions developed in many organs. These lesions consisted of necrosis and fibrinoid degeneration of arterioles and necrotizing arteriolitis which should not be confused with arteriolosclerosis. The same humoral mechanism which is responsible for experimental renal hypertension in the dog and other animals also obtains in the pathogenesis of experimental renal hypertension in the sheep and goat.

THE ETIOLOGY OF HYPERTENSION DUE TO COMPLETE RENAL ISCHEMIA

1. Perfusates of totally ischemic kidneys of cats contain a pressor substance which is not present in the perfusates of normal kidneys, ischemic hind limbs, or ischemic gravid uteri. 2. The pressor material in ischemic renal perfusates originates directly in the kidney as a result of complete ischemia. 3. The pressor principle contained in ischemic renal perfusates is the cause of the hypertension which follows the reestablishment of circulation in completely ischemic kidneys, since perfusates of unreleased completely ischemic kidneys contain more pressor material than perfusates of released ischemic kidneys of the same animal. 4. The pressor principle in ischemic renal perfusates is presumed to be renin for the following reasons, (a) Both substances are destroyed by boiling, (b) Both substances induce tachyphylaxis. (c) The configuration of both pressor curves is identical, (d) The pressor action of both is not reversed by 933F, proving they are not epinephrine-like substances. (e) When incubated with plasma, both form a heat-stable pressor substance. (f) The pressor effect of both is uninfluenced by a previous injection of cocaine, (g) Unreleased, completely ischemic kidneys yield more pressor material on extraction than do released ischemic kidneys of the same animal. 5. The perfusates of blood-free ischemic kidneys contain more renin than those of blood-filled ischemic kidneys. 6. A method is described by which the power of various substances to inhibit or enhance the production of renin in the ischemic kidney may be tested. 7. A small amount of the heat-stable pressor substance, presumably angiotonin or hypertensin, is formed by the reaction of the pressor material (renin) and plasma in the vessels of the kidney during the period of complete ischemia.

An assessment of adolescent satisfaction with reproductive primary healthcare services in the Eastern Cape Province, South Africa

OBJECTIVE

To assess adolescents' satisfaction with reproductive health services in Mdantsane Township, Eastern Cape Province, South Africa.

METHOD

A structured questionnaire was used to assess the levels of participants' satisfaction with reproductive health services. The sample consisted of 200 adolescents within the ages of 16 to 19 years. A response of "yes" indicated that the person was satisfied with the specific item, while a response of "no" indicated dissatisfaction with that item. A spreadsheet was developed to analyse data obtained and 95% was used as a cut off rate to define an appropriate level of client satisfaction.

RESULTS

Results indicated that adolescents were dissatisfied with reproductive health delivery at Mdantsane Township. Satisfaction responses on accessibility and confidentiality of services, options available to participants as well as staff friendliness fell below the stated cut off rate of 95%. From each item, the number of responses of satisfaction on reproductive health delivery at the primary health clinic was mostly below 89%.

CONCLUSION

In general, participants in this survey were dissatisfied with reproductive health services at the clinics at Mdantsane Township in the Eastern Cape Province.

Structures of a minimal human CFTR first nucleotide-binding domain as a monomer, head-to-tail homodimer, and pathogenic mutant

Upon removal of the regulatory insert (RI), the first nucleotide binding domain (NBD1) of human cystic fibrosis transmembrane conductance regulator (CFTR) can be heterologously expressed and purified in a form that remains stable without solubilizing mutations, stabilizing agents or the regulatory extension (RE). This protein, NBD1 387-646(Delta405-436), crystallizes as a homodimer with a head-to-tail association equivalent to the active conformation observed for NBDs from symmetric ATP transporters. The 1.7-A resolution X-ray structure shows how ATP occupies the signature LSGGQ half-site in CFTR NBD1. The DeltaF508 version of this protein also crystallizes as a homodimer and differs from the wild-type structure only in the vicinity of the disease-causing F508 deletion. A slightly longer construct crystallizes as a monomer. Comparisons of the homodimer structure with this and previously published monomeric structures show that the main effect of ATP binding at the signature site is to order the residues immediately preceding the signature sequence, residues 542-547, in a conformation compatible with nucleotide binding. These residues likely interact with a transmembrane domain intracellular loop in the full-length CFTR channel. The experiments described here show that removing the RI from NBD1 converts it into a well-behaved protein amenable to biophysical studies yielding deeper insights into CFTR function.

Otolith chemistry of prey fish consumed by a fish predator: does digestion hinder Russian doll techniques?

The effect of digestion by a predatory fish (largemouth bass Micropterus salmoides) on stable isotopic (delta(13)C and delta(18)O) and trace elemental (Sr:Ca and Ba:Ca) compositions of prey fish (bluegill Lepomis macrochirus) otoliths was investigated in a laboratory experiment. Trace element and stable-isotopic signatures of L. macrochirus otoliths were not significantly altered for up to 16 h after L. macrochirus were consumed by M. salmoides. Prey fish otoliths recovered from predator digesta can retain environmental stable isotopic and trace elemental signatures, suggesting that determination of environmental history for prey fishes by stable-isotope and trace-element analysis of otoliths recovered from stomachs of piscivorous fishes will be feasible.

Structure and dynamics of NBD1 from CFTR characterized using crystallography and hydrogen/deuterium exchange mass spectrometry

The DeltaF508 mutation in nucleotide-binding domain 1 (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR) is the predominant cause of cystic fibrosis. Previous biophysical studies on human F508 and DeltaF508 domains showed only local structural changes restricted to residues 509-511 and only minor differences in folding rate and stability. These results were remarkable because DeltaF508 was widely assumed to perturb domain folding based on the fact that it prevents trafficking of CFTR out of the endoplasmic reticulum. However, the previously reported crystal structures did not come from matched F508 and DeltaF508 constructs, and the DeltaF508 structure contained additional mutations that were required to obtain sufficient protein solubility. In this article, we present additional biophysical studies of NBD1 designed to address these ambiguities. Mass spectral measurements of backbone amide (1)H/(2)H exchange rates in matched F508 and DeltaF508 constructs reveal that DeltaF508 increases backbone dynamics at residues 509-511 and the adjacent protein segments but not elsewhere in NBD1. These measurements also confirm a high level of flexibility in the protein segments exhibiting variable conformations in the crystal structures. We additionally present crystal structures of a broader set of human NBD1 constructs, including one harboring the native F508 residue and others harboring the DeltaF508 mutation in the presence of fewer and different solubilizing mutations. The only consistent conformational difference is observed at residues 509-511. The side chain of residue V510 in this loop is mostly buried in all non-DeltaF508 structures but completely solvent exposed in all DeltaF508 structures. These results reinforce the importance of the perturbation DeltaF508 causes in the surface topography of NBD1 in a region likely to mediate contact with the transmembrane domains of CFTR. However, they also suggest that increased exposure of the 509-511 loop and increased dynamics in its vicinity could promote aggregation in vitro and aberrant intermolecular interactions that impede trafficking in vivo.

Structural analysis of a set of proteins resulting from a bacterial genomics project

The targets of the Structural GenomiX (SGX) bacterial genomics project were proteins conserved in multiple prokaryotic organisms with no obvious sequence homolog in the Protein Data Bank of known structures. The outcome of this work was 80 structures, covering 60 unique sequences and 49 different genes. Experimental phase determination from proteins incorporating Se-Met was carried out for 45 structures with most of the remainder solved by molecular replacement using members of the experimentally phased set as search models. An automated tool was developed to deposit these structures in the Protein Data Bank, along with the associated X-ray diffraction data (including refined experimental phases) and experimentally confirmed sequences. BLAST comparisons of the SGX structures with structures that had appeared in the Protein Data Bank over the intervening 3.5 years since the SGX target list had been compiled identified homologs for 49 of the 60 unique sequences represented by the SGX structures. This result indicates that, for bacterial structures that are relatively easy to express, purify, and crystallize, the structural coverage of gene space is proceeding rapidly. More distant sequence-structure relationships between the SGX and PDB structures were investigated using PDB-BLAST and Combinatorial Extension (CE). Only one structure, SufD, has a truly unique topology compared to all folds in the PDB.

Impact of the deltaF508 mutation in first nucleotide-binding domain of human cystic fibrosis transmembrane conductance regulator on domain folding and structure

Cystic fibrosis is caused by defects in the cystic fibrosis transmembrane conductance regulator (CFTR), commonly the deletion of residue Phe-508 (DeltaF508) in the first nucleotide-binding domain (NBD1), which results in a severe reduction in the population of functional channels at the epithelial cell surface. Previous studies employing incomplete NBD1 domains have attributed this to aberrant folding of DeltaF508 NBD1. We report structural and biophysical studies on complete human NBD1 domains, which fail to demonstrate significant changes of in vitro stability or folding kinetics in the presence or absence of the DeltaF508 mutation. Crystal structures show minimal changes in protein conformation but substantial changes in local surface topography at the site of the mutation, which is located in the region of NBD1 believed to interact with the first membrane spanning domain of CFTR. These results raise the possibility that the primary effect of DeltaF508 is a disruption of proper interdomain interactions at this site in CFTR rather than interference with the folding of NBD1. Interestingly, increases in the stability of NBD1 constructs are observed upon introduction of second-site mutations that suppress the trafficking defect caused by the DeltaF508 mutation, suggesting that these suppressors might function indirectly by improving the folding efficiency of NBD1 in the context of the full-length protein. The human NBD1 structures also solidify the understanding of CFTR regulation by showing that its two protein segments that can be phosphorylated both adopt multiple conformations that modulate access to the ATPase active site and functional interdomain interfaces.

Oral health knowledge and original practices of African traditional healers in Zonkizizwe and Dube, South Africa

Self reported oral health knowledge and practices of 83 traditional healers in Zonkizizwe (56) and Dube (27) Gauteng Province, South Africa were carried out using a questionnaire and clinical photographs of common oral conditions. The mean age for the total group was 49.5 with 35 males and 48 females. Although only 17 of the healers were members of a professional association, many indicated their willingness to join one. 40 (71%) of healers in Zonkizizwe kept written client records but far fewer 3 (11%) did so in Dube. More than 90% of traditional healers from both areas correctly identified photographs of gingival inflammation, dental caries and oral candidiasis. Over 50% of healers from both areas had patients who presented with mouth problems. Ninety percent of healers in Zonkizizwe referred patients to the formal health care sector but less than 50% in Dube did so. A vast majority of healers gave oral health advice to their patients, many of whom gave specific tooth brush instruction. The study provides an initial understanding of the practices of healers regarding oral health.

Structure of nucleotide-binding domain 1 of the cystic fibrosis transmembrane conductance regulator

Cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a chloride channel. Nucleotide-binding domain 1 (NBD1), one of two ABC domains in CFTR, also contains sites for the predominant CF-causing mutation and, potentially, for regulatory phosphorylation. We have determined crystal structures for mouse NBD1 in unliganded, ADP- and ATP-bound states, with and without phosphorylation. This NBD1 differs from typical ABC domains in having added regulatory segments, a foreshortened subdomain interconnection, and an unusual nucleotide conformation. Moreover, isolated NBD1 has undetectable ATPase activity and its structure is essentially the same independent of ligand state. Phe508, which is commonly deleted in CF, is exposed at a putative NBD1-transmembrane interface. Our results are consistent with a CFTR mechanism, whereby channel gating occurs through ATP binding in an NBD1-NBD2 nucleotide sandwich that forms upon displacement of NBD1 regulatory segments.

A structural genomics approach to the study of quorum sensing: crystal structures of three LuxS orthologs

BACKGROUND

Quorum sensing is the mechanism by which bacteria control gene expression in response to cell density. Two major quorum-sensing systems have been identified, system 1 and system 2, each with a characteristic signaling molecule (autoinducer-1, or AI-1, in the case of system 1, and AI-2 in system 2). The luxS gene is required for the AI-2 system of quorum sensing. LuxS and AI-2 have been described in both Gram-negative and Gram-positive bacterial species and have been shown to be involved in the expression of virulence genes in several pathogens.

RESULTS

The structure of the LuxS protein from three different bacterial species with resolutions ranging from 1.8 A to 2.4 A has been solved using an X-ray crystallographic structural genomics approach. The structure of LuxS reported here is seen to have a new alpha-beta fold. In all structures, an equivalent homodimer is observed. A metal ion identified as zinc was seen bound to a Cys-His-His triad. Methionine was found bound to the protein near the metal and at the dimer interface.

CONCLUSIONS

These structures provide support for a hypothesis that explains the in vivo action of LuxS. Specifically, acting as a homodimer, the protein binds a methionine analog, S-ribosylhomocysteine (SRH). The zinc atom is in position to cleave the ribose ring in a step along the synthesis pathway of AI-2.

The tetranucleotide UCAY directs the specific recognition of RNA by the Nova K-homology 3 domain

The Nova family of proteins are target antigens in the autoimmune disorder paraneoplastic opsoclonus-myoclonus ataxia and contain K-homology (KH)-type RNA binding domains. The Nova-1 protein has recently been shown to regulate alternative splicing of the alpha2 glycine receptor subunit pre-mRNA by binding to an intronic element containing repeats of the tetranucleotide UCAU. Here, we have used selection-amplification to demonstrate that the KH3 domain of Nova recognizes a single UCAY element in the context of a 20-base hairpin RNA; the UCAY tetranucleotide is optimally presented as a loop element of the hairpin scaffold and requires protein residues C-terminal to the previously defined KH domain. These results suggest that KH domains in general recognize tetranucleotide motifs and that biological RNA targets of KH domains may use either RNA secondary structure or repeated sequence elements to achieve high affinity and specificity of protein binding.

Sequence-specific RNA binding by a Nova KH domain: implications for paraneoplastic disease and the fragile X syndrome

The structure of a Nova protein K homology (KH) domain recognizing single-stranded RNA has been determined at 2.4 A resolution. Mammalian Nova antigens (1 and 2) constitute an important family of regulators of RNA metabolism in neurons, first identified using sera from cancer patients with the autoimmune disorder paraneoplastic opsoclonus-myoclonus ataxia (POMA). The structure of the third KH domain (KH3) of Nova-2 bound to a stem loop RNA resembles a molecular vise, with 5'-Ura-Cyt-Ade-Cyt-3' pinioned between an invariant Gly-X-X-Gly motif and the variable loop. Tetranucleotide recognition is supported by an aliphatic alpha helix/beta sheet RNA-binding platform, which mimics 5'-Ura-Gua-3' by making Watson-Crick-like hydrogen bonds with 5'-Cyt-Ade-3'. Sequence conservation suggests that fragile X mental retardation results from perturbation of RNA binding by the FMR1 protein.

An oral health promotion module for the primary health care nursing course in Acornhoek, South Africa

The severe personnel shortage in the health professions in most developing communities is well documented. This dearth of health workers and the widespread adoption of the primary health care approach (PHCA), requires that health professionals be trained to understand and effectively utilize the skills offered by other disciplines in the health care field. Nurses are expected to play active roles in the promotion of health including oral health, particularly in the rural under-served communities. There is a paucity of oral health education in nursing curricula. This article describes a 4-day module on oral health promotion developed and delivered to 36 nurses as part of a 12-month primary health care nursing (PHCN) training course. The module utilized a variety of educational methods and materials to facilitate and encourage both individual and group learning. The module was evaluated using both student academic attainment and perceptions as outcome measures. The evaluation and the experience of facilitating this module show that an oral health promotion module of short duration can sensitize nurses to the importance of oral health and increase oral health knowledge and skills.

Crystal structures of Nova-1 and Nova-2 K-homology RNA-binding domains

BACKGROUND

Nova-1 and Nova-2 are related neuronal proteins that were initially cloned using antisera obtained from patients with the autoimmune neurological disease paraneoplastic opsoclonus-myoclonus ataxia (POMA). Both of these disease gene products contain three RNA-binding motifs known as K-homology or KH domains, and their RNA ligands have been identified via binding-site selection experiments. The KH motif structure has been determined previously using NMR spectroscopy, but not using X-ray crystallography. Many proteins contain more than one KH domain, yet there is no published structural information regarding the behavior of such multimers.

RESULTS

We have obtained the first X-ray crystallographic structures of KH-domain-containing proteins. Structures of the third KH domains (KH3) of Nova-1 and Nova-2 were determined by multiple isomorphous replacement and molecular replacement at 2.6 A and 2.0 A, respectively. These highly similar RNA-binding motifs form a compact protease-resistant domain resembling an open-faced sandwich, consisting of a three-stranded antiparallel beta sheet topped by three alpha helices. In both Nova crystals, the lattice is composed of symmetric tetramers of KH3 domains that are created by two dimer interfaces.

CONCLUSIONS

The crystal structures of both Nova KH3 domains are similar to the previously determined NMR structures. The most significant differences among the KH domains involve changes in the positioning of one or more of the alpha helices with respect to the betasheet, particularly in the NMR structure of the KH1 domain of the Fragile X disease protein FMR-1. Loop regions in the KH domains are clearly visible in the crystal structure, unlike the NMR structures, revealing the conformation of the invariant Gly-X-X-Gly segment that is thought to participate in RNA-binding and of the variable region. The tetrameric arrangements of the Nova KH3 domains provide insights into how KH domains may interact with each other in proteins containing multiple KH motifs.

Genotoxicity from domestic use of organophosphate pesticides

This report describes the types of chromosome damage in peripheral blood found in patients exposed to domestic application of organophosphate pesticides. These changes serve as a biomarker of cumulative toxic exposure. Susceptible individuals show DNA damage as chromosome alterations. The importance of these findings is that the apparent genotoxic changes occurred from domestic application of two of the commonly used organophosphate pesticides in America and adds one more adverse potential effect from these hazardous chemicals. Peripheral blood from eight patients exposed to the domestic spraying of organophosphate pesticides was cultured and the chromosomes photographed. The types of chromosome alterations seen included chromatid and chromosome breaks, single and double minutes, dicentrics, rings, translocations, exchanges (including sister chromatid), and endoreduplications. Our findings support previous findings that organophosphate pesticides have genotoxic effects even at domestically sprayed levels.

The effectiveness of a school-based fluoride mouth rinse programme

The objective of this study was to determine the effectiveness of unsupervised weekly fluoride mouth rinsing (FMR) with 10 mls of 0.2 per cent sodium fluoride on the caries increment of permanent teeth in schoolchildren aged 6-12 years over a 3 year period. Caries was assessed using DMFT and DMFS indices (WHO, 1987). Over 2000 children from 4 schools in the Johannesburg area were selected at baseline. For analysis purposes pupils were pooled into 2 groups, those who received and those who did not receive the FMR. There were significant differences in mean decayed scores after 3 years. The percentage caries reduction achieved with the FMR was approximately 15 per cent. Reductions of up to 30 per cent have been recorded in previous studies of this nature. The overall caries reduction for this study period can be considered low.

Hope, coping, and adjustment among children with sickle cell disease: tests of mediator and moderator models

Tested mediator and moderator models of hope, coping, and adjustment in 39 children with sickle cell disease. In home interviews parents provided information on demographics and functional adjustment. Children self-reported levels of hope, coping strategies, and psychological adjustment. Coping strategies moderated, but did not mediate, the relationship between hope and adjustment. Hope was negatively associated with anxiety when active coping, support coping, and distraction coping was high. Avoidance coping did not moderate the hope-adjustment relationship but was positively related to anxiety. No effects were found for depressive symptoms or for the functional measures of adjustment.

Prevalence and severity of fluorosis in the primary and permanent dentition using the TSIF

This paper reports on the prevalence and severity of dental fluorosis in the primary and permanent teeth and the tooth surfaces of 262 school children aged 6-18 years from two communities in KwaNdebele (South Africa), the first with 8-9 ppm F-, and the second with 0.6-1.6 ppm F- in the drinking water. The Tooth Surface Index of Fluorosis (TSIF) was used to measure the degree of fluorosis. In both areas, the population prevalence, for primary and permanent teeth was more than 90 per cent. For the lower F- area, 40 per cent of tooth surfaces were free of fluorosis compared with only 22 per cent in the high F- area. Of the surfaces affected by fluorosis in the high F- area, 37 per cent scored in the categories 4-7, compared with 6 per cent in the lower F- area. This difference in severity was found to be statistically significant (P<0.001). This study has shown that, in two areas with significantly different levels of fluoride in the water supply, the population prevalences of fluorosis were similar, but significant differences existed in severity. The World Health Organization 1984 guidelines for Drinking-water Quality recommend that 1.5 ppm F- is the maximum acceptable concentration in drinking water but this may not be appropriate for South Africa.

A mobile dental system in southern Africa

Recent studies indicate a great need for dental treatment and preventive services in dentally underserved communities in southern Africa. Geographic inaccessibility, limited financial resources, and a maldistribution of dental personnel are the main barriers to oral health care. This project describes the evolution and utilization of a unique, purpose-built, mobile dental unit (MDU). From a compact 2 x 2.5 meter box trailer, an enclosed area of 8 x 9 meters is formed by deploying a cover system housed on top of the trailer. Once deployed, the unit becomes four fully equipped dental operatories and a combined waiting and educational area, with all-weather protection. Comprehensive care is provided by dental auxiliaries. The underlying philosophy of the service is based on the primary oral health care approach. To date, the MDU has visited a wide variety of rural and urban communities where several thousand patients have been examined and treated. Assessment of the MDU indicates that it is an effective and viable alternative oral health delivery system.

Suitability of nurses and school-teachers as oral health educators in Gazankulu--a pilot study

This study investigated the suitability of nurses and teachers as potential oral health educators. The assessment was based on a concept of suitability that embraced biological and psycho-social variables. These included oral health status, knowledge, attitudes and reported oral health behaviour. The study population comprised 48 nurses and 43 school-teachers. DMFT of nurses was 4, 6 and teachers 2,5. More than 80 percent of both groups required some form of periodontal treatment. An adequate but basic knowledge of the causes and prevention of oral disease was demonstrated. More that 50 percent of both groups did not visit a dentist annually. Attitudes reflected the belief that teeth are expendable and easily replaceable. In terms of the theoretical model these nurses and teachers do not meet all the criteria that define "suitable" oral health educators. The findings of the present study have provided a profile which has highlighted certain deficiencies in knowledge, attitudes and behaviour. Further research using this model requires the inclusion of motivational and interest variables.

Racial classification in dental literature: is it always necessary?

The purpose of the present study is to describe and analyse the use of terms (black, coloured, white, indian, african and non-white) that classify people for research purposes along racial lines. All scientific articles published in the Journal of the Dental Association of South Africa, from Jan 1979 to Dec 1988, were reviewed. Of the 493 articles covered, 92 made use of one or more of the terms, and 10 (11 per cent) either explained, defined, referenced and/or justified their use, while 09 per cent of the articles did not do so. Based on these reviews, it may be concluded that the use of these terms is not always necessary or justified and can reinforce thinking in racial rather than in social and behavioural terms. The unjustified usage of racial variables may limit our theoretical perspectives and lead us into questionable research.

Synthesis of thymine and alpha-putrescinylthymine in bacteriophage phi W-14-infected Pseudomonas acidovorans

Host DNA synthesis stopped about 10 min after the infection of Pseudomonas acidovorans with bacteriophage phi W-14, but host DNA was not degraded to acid-soluble fragments. The synthesis of host but not of phage DNA was inhibited by 5-fluorodeoxyuridine. The nucleotide pools of infected cells did not contain dTTP, and infection resulted in the appearance of dTTPase activity. Although ornithine labeled the alpha-putrescinylthymine residues of phi W-14 DNA, ornithine-labeled nucleotides were not detected in infected cells. A new deoxynucleoside triphosphate did appear in infected cells, but it was not labeled by ornithine. It is concluded that the thymine and alpha-putrescinylthymine in phi W-14 DNA are synthesized at the polynucleotide level.

Lithium plus reserpine in refractory manic patients

The authors report on six refractory manic or schizo-affective manic male outpatients who failed to respond to lithium combined with a neuroleptic. A beneficial response was noted in most patients when reserpine was substituted for their currently prescribed standard neuroleptic; in some cases lithium dosage could then be reduced. No major side effects were encountered. The use of reserpine may offer an alternative mode of therapy for manic patients who cannot tolerate large doses of lithium or do not completely respond to lithium either alone or in combination with a standard neuroleptic.

Alkali lability of bacteriophage phi W-14 DNA

The molecular weight of bacteriophage phi W-14 DNA, determined by velocity sedimentation in neutral sucrose gradients, was 92 +/- 6 X 10(6). The DNA showed marked fragmentation in alkaline sucrose gradients. This fragmentation was not a consequence of preexisting single-strand interruptions in the DNA, since thermal denaturation of DNA yielded intact single strands. The alpha-putrescinylthymine groups in phi W-14 DNA appeared to be labile; some, or parts of some, of these groups were cleaved from the DNA in alkali.