Development of a sequential enzymolysis approach for the evaluation of the bioaccessibility of Cd and Pb from cocoa

An in vitro model simulating enzymatic activity in the gastrointestinal tract was developed for the assessment of the potential bioaccessibility of Cd and Pb in cocoa powder and liquor. The model was based on the sequential extraction with simulated gastric and intestinal juices; the residue after the latter extraction was further investigated by using, in parallel, solutions of phytase and cellulase. The solubility of Cd and Pb in the corresponding enzymatic extracts was measured by ICP MS. The bioaccessibility of Cd in cocoa varied from 10 to 50% in gastrointestinal conditions. An additional 20 or 30% of Cd could be recovered by phytase and cellulase, respectively. The bioaccessibility of Pb in gastrointestinal conditions did not exceed 5-10%. Only a few percent more of this metal could be recovered by extraction with phytase and cellulase.

Mismatch repair deficiency and CpG island hypermethylation in sporadic colon adenocarcinomas

Many studies have documented CpG island hypermethylation in human colon adenocarcinomas. Several of these reports have additionally found such CpG island hypermethylation to be more extensive in tumors with a mismatch-repair deficiency, as revealed by microsatellite instability (MSI+). Because the source of samples used in these prior studies may not have been representative of the general population, we have reinvestigated this issue using samples from a population-based study. A total of 15 MSI+ tumors were identified, and they were compared with 47 MSI- tumors that were similar in distribution by age, sex, and race. Microdissected tumor and normal adjacent mucosal DNA samples from each patient were subjected to a quantitative DNA methylation analysis at 13 separate CpG dinucleotides located in five CpG islands in four different genes [APC, ESR1 (ER), CDKN2A (p16; promoter and exon 2), and MLH1]. Four of five CpG islands showed a statistically significantly increased level of methylation in tumor tissue compared with adjacent normal mucosa. In contrast to previous studies, we did not find any statistically significant correlations between MSI status and methylation levels of any of the CpG islands other than MLH1. Furthermore, we observed a positive correlation between MLH1 methylation and CDKN2A methylation (P = 0.03), whereas no association was noted between MSI positivity and CDKN2A methylation (P = 0.95). The latter results suggest a possible defect in the protection against CpG island hypermethylation shared between CDKN2A and MLH1 and do not support the notion of a functional association between CDKN2A methylation and the phenotype of mismatch repair deficiency.

Stepwise deletions of polyA sequences in mismatch repair-deficient colorectal cancers

PolyA simple repeat sequence deletions are common in tumors with microsatellite instability (MSI+). Such deletions occur one base at a time in DNA mismatch repair (MMR)-deficient yeast suggesting larger deletions in human MSI+ tumors represent multiple sequential stepwise losses. Sum total deletions in four polyA repeats were variable (between -17 to -45 bp) in 20 sporadic MSI+ colorectal cancers. Progressive but less extensive total deletions (maximum of -12 bp) occurred in similar polyA sequences in MMR-deficient mice (mlh1-/-) up to 478 days old. PolyA repeat lengths were relatively stable but already shortened in the MMR-deficient cell line HCT116. A transgene with 26 A's transfected into HCT116 shortened an average of 3.8 bases pairs after 469 days in culture, less than average deletions of BAT25 (-5.3) or BAT26 (-9.0) in MSI+ cancers. These findings further suggest that extensive polyA deletions common in MSI+ tumors likely reflect multiple stepwise smaller deletions that accumulate more than hundreds of divisions after loss of MMR.

Structures of disease-specific serum alpha-fetoprotein isoforms

Alpha-fetoprotein (AFP) is widely used as a serological marker in the diagnosis of hepatocellular carcinoma (HCC) and non-seminomatous germ cell tumours (NSGCT). By application of isoelectric focusing (IEF) disease-specific AFP isoforms can be identified. Three major bands are apparent: + 1 (associated with 'benign' liver disease), + II (associated with HCC) and +III (associated with NSGCT). Recently, we have characterized the predominant glycans of human serum AFP and now report the application of these findings and electrospray ionization-mass spectrometry (ESI-MS) to the determination of the glycan composition of the isoforms present in the sera of 12 patients with HCC and of one patient with NSGCT. ESI-MS allowed simultaneous identification of various AFP glycoforms in purified serum AFP. Seven glycoforms were identified, but with different abundance in the sera of the HCC patients, whereas six glycoforms were identified in the serum from the NSGCT patient. The glycan structures of these glycoforms were deduced from their observed masses. AFP glycoforms carrying a single biantennary complex-type N -glycan appeared as the predominant glycoforms, whereas those carrying both N -glycan and O -glycan appeared as minor glycoforms. Correlation between the abundance of the AFP glycoforms and the IEF band intensity suggested that different degrees in sialylation cause the formation of isoforms. This contention was subsequently supported by the ESI-MS and kinetic in vitro desialylation studies on purified Bands + l and + lI AFPs. Our findings indicate that HCC-associated isoforms (Band + II) represent a group of glycoproteins whose carbohydrate structures are all characterized by being mono-sialylated, whereas those associated with benign liver disease and NSGCT are di- and a-sialo species, respectively. Knowledge of the structure of the tumour-specific isoforms should form an important basis for clinically useful assays.

The Short Form 36 (SF-36) Health Survey: normative data for the Irish population

BACKGROUND

Generic measures of quality of life have a wide application in health research. They measure disease impact by comparing scores in patient groups with a healthy population. They also facilitate comparative studies between different patient groups. The SF-36 Health Survey quantifies respondents' perceptions of their functioning in eight dimensions of daily life.

AIM

The aim of this study was to set normative values for the SF-36 in the Irish population aged 18 years and over.

METHOD

A random sample of 800 subjects was drawn from the electoral register using the RANSAM method of sampling.

RESULTS

Two hundred and ninety five (37%) valid questionnaires were returned for analysis. The SF-36 was found to have acceptable internal consistency and validity. Normative values for the total population are presented, in addition to results for males and females across seven age groups. Ageing was associated with a decline in the physical dimensions of health.

CONCLUSIONS

There was no evidence to suggest that there were significant differences in health status between males and females, or between this Irish sample and the published norms for the US population.

MethyLight: a high-throughput assay to measure DNA methylation

Cytosine-5 DNA methylation occurs in the context of CpG dinucleotides in vertebrates. Aberrant methylation of CpG islands in human tumors has been shown to cause transcriptional silencing of tumor-suppressor genes. Most methods used to analyze cytosine-5 methylation patterns require cumbersome manual techniques that employ gel electrophoresis, restriction enzyme digestion, radiolabeled dNTPs or hybridization probes. The development of high-throughput technology for the analysis of DNA methylation would significantly expand our ability to derive molecular information from clinical specimens. This study describes a high-throughput quantitative methylation assay that utilizes fluorescence-based real-time PCR (TaqMan) technology that requires no further manipulations after the PCR step. MethyLight is a highly sensitive assay, capable of detecting methylated alleles in the presence of a 10,000-fold excess of unmethylated alleles. The assay is also highly quantitative and can very accurately determine the relative prevalence of a particular pattern of DNA methylation. We show that MethyLight can distinguish between mono-allelic and bi-allelic methylation of the MLH1 mismatch repair gene in human colorectal tumor specimens. The development of this technique should considerably enhance our ability to rapidly and accurately generate epigenetic profiles of tumor samples.

Physical function, employment and quality of life in end-stage renal disease

INTRODUCTION

The impact of end-stage renal disease (ESRD) on quality of life (QoL) can be measured in terms of physical, psychological and social consequences, including the ability to work.

SUBJECTS AND METHODS

This multi-center, cross-sectional study explored relationships between QoL, employment status and physical function in ESRD patients aged 18-65 years, via a customised interviewer-administered questionnaire, which included the SF-36 health survey. The International Labour Office method was applied to describe employment rate.

RESULTS

144 patients (85 male, 49 female), comprising 49 haemodialysis (HD), 35 peritoneal dialysis (PD) and 60 renal transplant (TX) patients were studied. Mean age was 44 +/- 12 years. 32 were voluntarily not working, leaving 112 in the labour force. Of the latter, 49% were unemployed, in contrast with the concurrent national rate of 10%. QoL in the ESRD group was reduced in the SF-36 physical and social dimensions compared to population norms. Unemployed ESRD patients scored significantly lower than those employed in physical function, role physical, bodily pain, general health, vitality and role emotional scales. Logistic regression demonstrated that multiple comorbidities (p<0.005), a premorbid physical occupation (p<0.05) and poor physical function (p<0.05) predicted unemployment in ESRD independent of all other variables. Multiple regression showed that age (p<0.05), female sex (p<0.05) and a diagnosis of musculoskeletal disease (p<0.005) were independent predictors of poor physical function.

CONCLUSIONS

These findings suggest that vocational rehabilitation of ESRD patients must consider physical function and occupational demands as well as co-morbidity and that musculoskeletal disease is key factor in impaired physical function.

Multiple categorization of search results

The number of publications available to physicians and patients is increasing at an alarming rate. Although users can use tools to assist in reformulating their query, this approach is ineffective when their information needs are imprecise or many documents are relevant. The ranked list presentation of documents provides little or no information relating documents to the initial query or to each other. We argue that information overload can be reduced if documents are placed in categories that (a) relate to the initial query and (b) contain a manageable number of documents. Dynamic Categorization is a knowledge-based approach that satisfies (a), however the number of documents in a category may still be large. We demonstrate that using the same approach to re-categorize the documents in large categories reduces the number of documents in the subcategory, and maintains a clear relationship to the initial query.

Identification of hepatitis C virus seroconversion resulting from nosocomial transmission on a haemodialysis unit: implications for infection control and laboratory screening

Hepatitis C virus (HCV) seroconversion was detected by routine screening in a haemodialysis patient, Patient 1. Serological investigations were undertaken over the following 3 months to determine if further transmission to other patients on the unit had occurred. No additional cases were identified. Twenty-two haemodialysis patients known to have HCV infection were investigated using molecular epidemiological methods to determine if transmission between patients had occurred. HCV viraemia was demonstrated by polymerase chain reaction in 19 of 22 patients (86%). Genotyping showed that eight patients were infected with genotype 1, three with genotype 3 and eight, including Patient 1, with genotype 2. Phylogenetic analysis of viral sequences from the eight patients with genotype 2 revealed three, including Patient 1,with a novel subtype of HCV type 2, and revealed close similarity between viral sequences from patient 1 and those from one other patient, suggesting transmission. This was consistent with haemodialysis histories. Among other patients with genotype 2, there were two with subtype 2a and three others with three separate novel subtypes, as yet undesignated. With the exception of patient 1, all patients infected with novel subtypes were of Afro-Caribbean origin. The HCV prevalence among patients on the haemodialysis unit was high (14%), which may reflect the ethnicity of our haemodialysis population. This case emphasises the risk of nosocomial transmission and the importance of infection control procedures on haemodialysis units, and highlights the usefulness of molecular epidemiological techniques for the investigation of outbreaks of HCV infection.

rhBMP-collagen sponges as osteoinductive devices: effects of in vitro sponge characteristics and protein pI on in vivo rhBMP pharmacokinetics

Osteoinductive devices, comprised of biodegradable collagen scaffolds and recombinant human Bone Morphogenetic Proteins (rhBMPs), are being currently pursued for local bone induction. To better understand the biological performance of such devices, we have carried out a series of studies to investigate the effects of sponge properties and protein structural features on the pharmacokinetics of implanted rhBMPs. The results indicated little dependence of the rhBMP-2 pharmacokinetics on the in vitro determined sponge properties. The protein isoelectric point (pI), on the other hand, was found to significantly affect the initial implant retention of rhBMPs, but not the subsequent pharmacokinetics. A 100-fold difference in the implant-retained dose could be observed depending on the type of rhBMP implanted. We conclude that protein structural features are important variables controlling in vivo pharmacokinetics of rhBMPs, and possibly the osteoinductive potency of the devices.

Nurses' reflections on ethical decision making: implications for leaders

This study documents moral/ethical situations that nurses in acute care hospitals experience as described by the nurses themselves. Findings show on-going evidence of caring, connectedness, and context. Decisions made often showed a balance between perceived ideal action and realistic action. This study also demonstrates that nurses need more opportunity for ethical reflection, that employers must become more involved in ethics education, and that further study of ethical decision making is needed as professionals and clients become more diverse.

Impact of litigation on quality of life outcomes in patients with chronic low back pain

Low back pain progresses to chronic low back pain (CLBP) in 5-10 per cent of patients. A Multi-disciplinary Pain Management Programme was tested in 20 patients (m = 4, f = 16). This regime involved psychological and behaviour modification strategies, combined with intensive exercise. Treatment outcome in terms of impairment was assessed by lumbar flexibility, trunk muscle endurance and pain. The disability assessed was exercise fitness and handicap was assessed using the Sickness Impact Profile (SIP) to define the impact of the condition on the patient's life. Overall the patients showed significant improvement (p < 0.05) in all of the measured variables. Patients with on-going litigation however (n = 11) showed no significant improvement in the SIP quality of life score, although they shared the significant improvements attained by the whole group in the domains of impairment (lumbar flexibility, trunk muscle endurance and pain) and disability (exercise fitness).

Synchrotron X-ray studies suggest that the core of the transthyretin amyloid fibril is a continuous beta-sheet helix

BACKGROUND

Amyloid diseases, which include Alzheimer's disease and the transmissible spongiform encephalopathies, are characterized by the extracellular deposition of abnormal protein fibrils derived from soluble precursor proteins. Although different precursors seem to generate similar fibrils, no adequate molecular structure of amyloid fibrils has been produced using modern techniques. Knowledge of the fibril structure is essential to understanding the molecular mechanism of amyloid formation and could lead to the development of agents to inhibit or reverse the process.

RESULTS

The structure of amyloid fibrils from patients with familial amyloidotic polyneuropathy (FAP), which are derived from transthyretin (TTR) variants, has been investigated by fibre diffraction methods using synchrotron radiation. For the first time a significant high-angle diffraction pattern has been observed showing meridional reflections out to 2 A resolution. This pattern was fully consistent with the previously reported cross-beta structure for the fibril, but also reveals a new large scale fibre repeat of 115 A. We interpret this pattern as that of a repeating unit of 24 beta strands, which form a complete helical turn of beta sheet about an axis parallel to the fibre axis. This structure has not been observed previously. We have built a model of the protofilament of the FAP amyloid fibril based on this interpretation, composed of four beta sheets related by a single helix axis coincident with the fibre axis, and shown that it is consistent with the observed X-ray data.

CONCLUSIONS

This work suggests that amyloid fibrils have a novel molecular structure consisting of beta sheets extended in regular helical twists along the length of the fibre. This implies that the polypeptide chains in the fibres are hydrogen-bonded together along the entire length of the fibres, thereby accounting for their great stability. The proposed structure of the FAP fibril requires a TTR building block that is structurally different from the native tetramer. This is likely to be either a monomer or dimer with reorganized or truncated beta sheets, suggesting that amyloid formation may require significant structural change in precursor proteins.

Asbestos exposure of building maintenance personnel

The exposures of building maintenance personnel and occupants to airborne asbestos fibers, and the effects of operations and maintenance programs on those exposures, continue to be an important public health issue. The subject of this investigation was a large metropolitan county with numerous public buildings which routinely conducted air sampling for asbestos. A total of 302 personal air samples in nine task categories collected during maintenance worker activities in proximity to asbestos-containing materials were analyzed; 102 environmental air samples in four task categories were also analyzed. The arithmetic means of the 8-hr time weighted average exposures for personal sampling for each task category were all below the Occupational Safety and Health Administration permissible exposure level of 0.1 fibers (f)/cc > 5 microm. The highest mean 8-hr time weighted average exposure was 0.030 f/cc > 5 microm for ceiling tile replacement. The maximum asbestos concentration during sample collection for environmental samples was 0.027 f/cc > 5 microm. All asbestos-related maintenance work was done within the framework of an Operations and Maintenance Program (OMP) which utilized both personal protective equipment and controls against fiber release/dispersion. Results are presented in association with specific OMP procedures or controls. These results support the effectiveness of using Operations and Maintenance Programs to manage asbestos in buildings without incurring unacceptable risk to maintenance workers performing maintenance tasks.

2.0 A resolution structure of a ternary complex of pig muscle phosphoglycerate kinase containing 3-phospho-D-glycerate and the nucleotide Mn adenylylimidodiphosphate

The crystal structure of a ternary complex of pig muscle phosphoglycerate kinase (PGK) containing 3-phosphoglycerate (3-PG) and manganese adenylylimidodiphosphate (Mn AMP-PNP) has been determined and refined at 2.0 A resolution. The complex differs from the true substrate ternary complex only in the presence of an imido- rather than an oxylink between beta- and gamma-phosphates of the bound nucleotide. The 3-PG is bound in a similar manner to that observed in binary complexes. The nucleotide is bound in a similar manner to Mg ADP except that the metal ion is coordinated by all three alpha-, beta-, and gamma-phosphates, but not by the protein. The gamma-phosphate, which is transferred in the reaction, is not bound by the protein. One further characteristic of the ternary complex is that Arg-38 moves to a position where its guanidinium group makes a triple interaction with the N-terminal domain, the C-terminal domain, and the 1-carboxyl group of the bound 3-PG. Although a hinge-bending conformation change is seen in the ternary complex, it is no larger than that observed in the 3-PG binary complex. To reduce that distance between two bound substrates to a value consistent with the direct in-line transfer known to occur in PGK, we modeled the closure of a pronounced cleft in the protein structure situated between the bound substrates. This closure suggested a mechanism of catalysis that involves the "capture" of the gamma-phosphate by Arg-38 and the N-terminus of helix-14, which has a conserved Gly-Gly-Gly phosphate binding motif. We propose that nucleophilic attack by the 1-carboxyl group of the 3-PG on the gamma-phosphorus follows the capture of the gamma-phosphate, leading to a pentacoordinate transition state that may be stabilized by hydrogen bonds donated by the NH groups in the N-terminus of helix 14 and the guanidinium group of Arg-38. During the course of the reaction the metal ion is proposed to migrate to a position coordinating the alpha- and beta-phosphates and the carboxyl group of Asp-374. The mechanism is consistent with the structural information from binary and ternary substrate complexes and much solution data, and gives a major catalytic role to Arg-38, as indicated by site-directed mutagenesis.

Granulocyte-macrophage colony-stimulating factor and interferon-gamma prevent dexamethasone-induced immunosuppression of antifungal monocyte activity against Aspergillus fumigatus hyphae

Treatment with corticosteroids is an important risk factor for development of invasive aspergillosis. We evaluated the effect of dexamethasone (DEX) on superoxide anion (O2-) release and damage caused by elutriated human monocytes (EHM) on unopsonized hyphae of Aspergillus fumigatus. In addition, we studied the effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma (IFN-gamma) on these functions of DEX-treated EHM. Treatment of EHM with concentrations of DEX ranging from 5 to 500 nM (1.4-140 ng ml-1) for 48 h suppressed O2- release in response to phorbol myristate acetate in a dose-dependent fashion. Similarly, DEX significantly suppressed hyphal damage caused by EHM as measured by colorimetric MTT assay. Both GM-CSF (5 ng ml-1) and IFN-gamma (1.2 ng ml-1) added at day 0 to the EHM together with DEX (500 nM) significantly enhanced O2- release and percentage hyphal damage, preventing the DEX-induced suppression of EHM function. Thus, GM-CSF and IFN-gamma prevented the deleterious effects of DEX on antifungal activity of EHM against Aspergillus suggesting a potential therapeutic role in patients at risk for or suffering from invasive aspergillosis.

Effects of macrophage colony-stimulating factor on antifungal activity of mononuclear phagocytes against Aspergillus fumigatus

The effects of recombinant human macrophage colony-stimulating factor (M-CSF) on antifungal activity of human monocytes (MNC), MNC-derived macrophages (MDM), and rabbit pulmonary alveolar macrophages (PAM) against Aspergillus fumigatus were studied. MNC-induced hyphal damage was augmented by incubation with M-CSF (P = .027); PAM-induced hyphal damage was moderately enhanced by M-CSF (P = .046). Phagocytosis of Aspergillus conidia by MDM and PAM was strongly enhanced by M-CSF (P < .01). MNC pretreated with M-CSF exhibited enhanced superoxide anion production in response to PMA (P = .026). This effect was not associated with increased levels of mRNA transcripts of the components of NADPH oxidase, the enzyme responsible for superoxide anion production. M-CSF augments antifungal activity of mononuclear phagocytes against both conidia and hyphae of Aspergillus fumigatus partly by enhancement of oxidation-dependent mechanisms and may have an important immunomodulatory role in prevention and treatment of invasive aspergillosis in leukopenic patients.

Effects of granulocyte colony-stimulating factor and interferon-gamma on antifungal activity of human polymorphonuclear neutrophils against pseudohyphae of different medically important Candida species

Polymorphonuclear neutrophils (PMNs) are the major host defense against pseudohyphae, the invasive form of Candida species. We studied the effects of granulocyte colony-stimulating factor (G-CSF) and interferon-gamma (IFN-gamma) on the PMN-induced damage of pseudo-hyphae of Candida albicans, Candida tropicalis, and Candida parapsilosis in vitro by using two antifungal assays: a modified limiting dilution assay and a colorimetric metabolic 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. PMNs from healthy volunteers were incubated with either G-CSF (100-10,000 U/ml) or IFN-gamma (10-5000 U/ml) or buffer at 37 degrees C for 90 min and their capacity to damage nonopsonized pseudohyphae was then measured. C. tropicalis appeared to be the most susceptible species, whereas C. parapsilosis showed the highest rate of resistance to PMN damage. G-CSF (500-10,000 U/ml) and IFN-gamma (100-1000 U/ml) enhanced the antifungal activity of PMNs against C. albicans pseudo-hyphae (P < .01 and P < .05). Among the others, G-CSF enhanced PMN-induced damage of C. parapsilosis at concentrations 500-10,000 U/ml (P < .05), whereas it enhanced damage of C. tropicalis only at 10,000 U/ml (P < .01). IFN-gamma (100-1000 U/ml)-primed PMNs also caused augmented damage of C. parapsilosis (P < .05) but not of C. tropicalis at the same concentrations. Species-dependent differences exist in the responses of PMNs to Candida pseudohyphae and G-CSF as well as IFN-gamma are important immunomodulators of phagocytic host defenses against them.

The refined structure of the quinoprotein methanol dehydrogenase from Methylobacterium extorquens at 1.94 A

BACKGROUND

Methanol dehydrogenase (MDH) is a bacterial periplasmic quinoprotein; it has pyrrolo-quinoline quinone (PQQ) as its prosthetic group, requires Ca2+ for activity and uses cytochrome cL as its electron acceptor. Low-resolution structures of MDH have already been determined.

RESULTS

The structure of the alpha 2 beta 2 tetramer of MDH from Methylobacterium extorquens has now been determined at 1.94 A with an R-factor of 19.85%.

CONCLUSIONS

The alpha-subunit of MDH has an eight-fold radial symmetry, with its eight beta-sheets stabilized by a novel tryptophan docking motif. The PQQ in the active site is held in place by a coplanar tryptophan and by a novel disulphide ring formed between adjacent cysteines which are bonded by an unusual non-planar trans peptide bond. One of the carbonyl oxygens of PQQ is bonded to the Ca2+, probably facilitating attack on the substrate, and the other carbonyl oxygen is out of the plane of the ring, confirming the presence of the predicted free-radical semiquinone form of the prosthetic group.

Antifungal activity of elutriated human monocytes against Aspergillus fumigatus hyphae: enhancement by granulocyte-macrophage colony-stimulating factor and interferon-gamma

Human monocytes are important effector cells in host defenses against Aspergillus hyphae, and as elutriated monocytes (EHM) they may be transfused in large quantities to leukopenic patients with invasive aspergillosis. The antifungal activity of EHM against Aspergillus hyphae was compared with that of polymorphonuclear leukocytes (PMNL). The effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma (IFN-gamma) on superoxide anion (O2-) release and on hyphal damage caused by EHM against unopsonized A. fumigatus hyphae was investigated. EHM had antihyphal activity comparable to that of PMNL. GM-CSF significantly augmented O2- release by EHM in response to PMA. Also, both GM-CSF and IFN-gamma significantly enhanced the antifungal activity of EHM compared with untreated controls. Thus, EHM have demonstrable antifungal activity against Aspergillus hyphae that may be increased by GM-CSF and IFN-gamma, suggesting their potential therapeutic role in immune reconstitution of effector cells.

Prostaglandin synthase. At the heart of the matter

The structure of prostaglandin synthase, the target of aspirin therapy in cardiovascular disease, reveals a remarkable integration of the enzyme's catalytic and membrane-binding properties.

Protective wear and instrument sterilisation/disinfection in UK general dental practice

The 18,000 United Kingdom general dental practitioners registered for National Health Service (NHS) practice were surveyed in July 1991 to assess their current use of protective gloves, eyewear and masks, and instrument sterilisation. Nearly 7,000 (6,588) valid responses were obtained immediately; of these, 70% of practitioners wore gloves routinely for clinical work, but only 14.5% donned new gloves for each patient. About 60% wore protective eyewear routinely or all the time but 12% never wore eye protection, and only 36% of practitioners used masks. Autoclaves or chemical solutions were the most popular methods to disinfect handpieces, but less than half the respondents stated that handpieces were sterilised or disinfected after each patient use. Most respondents (81%) routinely used autoclaves for sterilisation of other instruments. Although the response rate to the questionnaire was low, the results indicate that, despite the risks of, and publicity about, cross-infection, a substantial number of NHS dental practitioners may not adequately disinfect or sterilise their equipment between patients.

Defective antifungal activity of monocyte-derived macrophages from human immunodeficiency virus-infected children against Aspergillus fumigatus

Invasive aspergillosis recently has been encountered in adults and children with human immunodeficiency virus (HIV) infection even without known risk factors, such as neutropenia or corticosteroid therapy. Macrophages play a significant role in the host defenses against Aspergillus organisms by ingesting conidia and preventing their germination to hyphae. The antifungal activity of peripheral blood monocyte-derived macrophages (MDM) from 19 HIV-infected children was compared with that of 16 normal controls. The phagocytic activity of patients' MDM, measured as percentage of phagocytosis, was significantly decreased compared with normal donors (P = .014). In addition, the inhibitory activity of MDM on germination of intracellular A. fumigatus conidia was significantly impaired in patients compared with normal controls (P = .016). There was no significant difference in the defects between patients with lower or higher CD4 lymphocyte counts. Impairment of antifungal activity of macrophages may contribute to the susceptibility of HIV-infected patients to aspergillosis.

Management of variceal bleeding in the 1990s

BACKGROUND

Variceal bleeding is a common and serious problem.

OBJECTIVE

To review the current management of patients with variceal bleeding.

SUMMARY

Therapeutic options now include pharmacologic reduction of portal hypertension, endoscopic obliteration of varices, placement of decompressive shunts (both surgical and percutaneous), and liver transplantation. Each of these options may be required in different settings. A nonselective beta blocker can prophylactically reduce the risk of an initial bleed. Acute variceal bleeding is best managed by endoscopic sclerosis. Selection of therapy to prevent recurrent bleeding should be based on a full evaluation of the risk of bleeding and of liver failure.

CONCLUSIONS

Successful management requires a multidisciplinary team, full patient evaluation, and selection of appropriate therapy.

Impairment of neutrophil antifungal activity against hyphae of Aspergillus fumigatus in children infected with human immunodeficiency virus

Human immunodeficiency virus (HIV)-infected patients may acquire invasive aspergillosis without previously recognized risk factors, such as neutropenia or corticosteroid therapy. Because neutrophils (PMNL) are an important component of host defense in aspergillosis, the antifungal activity of PMNL against hyphae of Aspergillus fumigatus in 31 HIV-infected children was assessed. Hyphal damage was unaffected in 15 HIV-infected children with age-adjusted CD4 cell counts > or = 25% of the normal median value; it was decreased in 16 with CD4 cell counts < 25% (both vs. 20 healthy controls, P = .001. Incubation with sera from 12 of 14 HIV-infected children but not with the recombinant HIV proteins gp120, gp41, and p24 suppressed antifungal activity of normal PMNL compared with normal serum (P = .002). Pretreatment of defective PMNL from 5 patients with granulocyte colony-stimulating factor (G-CSF) partially corrected the defect (P = .002). These findings suggest that impaired serum-mediated antifungal activity against Aspergillus hyphae exists in PMNL of HIV-infected patients with low CD4 cell counts; G-CSF may improve this activity.

The control of cross-infection in UK clinical dentistry in the 1990s: immunisation against hepatitis B

Thirty thousand dentists and clinical ancillary staff in the UK were surveyed in July 1991 to assess the current state of immunisation against hepatitis B virus (HBV). About 11,000 responded immediately and nearly 94% of these had been, or were being, immunised against HBV. Nearly all dentists and therapists (94% in each group), 95% of hygienists, and 96% of dental surgery assistants had been immunised. However, one half of the respondents were at or approaching 5 years post-immunisation, the time when booster immunisation is recommended. About 53% of most responding clinical dental staff had been vaccinated 4 to 5 years before the survey, but, of these, nearly 81% had not had booster immunisation. Booster immunisation will now be indicated for most dental clinical personnel.

Synthesis and antitumor activity of 9-[(carbamoyloxy)alkyl]anthracyclines: a novel class of anthracycline derivatives

A number of 4-demethoxyanthracyclines having hydroxylalkyl functions at the 9-position have previously been synthesized and shown to have potent antitumor activity. A series of carbamate derivatives of these (hydroxyalkyl)anthracyclines have now been prepared, many of which possess considerably greater efficacy in an L-1210 leukemia test system than do the parent alcohols or the known anthracyclines daunorubicin (1), doxorubicin (2), and 4-demethoxydaunorubicin (3). Phenylcarbamate 8a was more active than methyl analogue 8b, while the 4'-deoxy and 4'-epi phenylcarbamates 17 and 18 showed particularly high efficacy at optimal dose levels similar to that of doxorubicin. Secondary carbamates were more potent, with the 13R isomer 23 having significantly higher efficacy than 13S analogue 24.

Synthesis and antitumor activity of novel 4-demethoxyanthracyclines

A versatile and efficient synthetic route to 4-demethoxyanthracyclinones has been utilized in the preparation of a number of aglycons having 9-alkyl, 9-(hydroxylalkyl), or 9-carbamoyl substituents. Silver trifluoromethanesulfonate catalyzed coupling of these aglycons with various daunosamine derivatives has yielded a series of novel anthracyclines which have been evaluated as antitumor agents. 9-Alkylanthracyclines 22, 23, 33, and 34 have higher efficacy vs L-1210 leukemia than the parent 4-demethoxydaunorubicin (21), or the natural anthracyclines daunorubicin (1) and doxorubicin (2). 9-(Hydroxyalkyl) derivatives have in most cases high efficacy but are slightly less potent than 21. 9-Methyl analogue 22 has higher efficacy vs P388 leukemia than other anthracyclines tested, while 9-(hydroxymethyl) derivative 37 retains similar efficacy to anthracyclines 1, 2, and 21 but is considerably more potent. The N-substituted 9-carbamoylanthracyclines are devoid of antitumor activity.

Simultaneous enzyme immunoassay of two thyroid hormones

We describe an enzyme immunoassay in which the two thyroid hormones, triiodothyronine and thyroxin, are measured simultaneously in a single tube. The method involves labeling the two with separate enzymes (beta-galactosidase and alkaline phosphatase, respectively), whose catalyzed reactions can easily be distinguished from each other by absorption spectrophotometry, with o-nitrophenyl-beta-galactoside and phenolphthalein monophosphate as substrates. Performance of this dual assay method compares well with that of conventional single-hapten enzyme-labeled assays, and results compare well with those by two single-hapten radioimmunoassays. The dual assay has certain advantages over single-hapten methods: smaller sample volume, lower reagent cost, and shorter overall assay time. As presented here, the use of enzyme labels to measure two (or more) haptens simultaneously represents a significant advance in the use of immunoassay techniques.

Simultaneous enzyme immunoassay of two thyroid hormones

We describe an enzyme immunoassay in which the two thyroid hormones, triiodothyronine and thyroxin, are measured simultaneously in a single tube. The method involves labeling the two with separate enzymes (beta-galactosidase and alkaline phosphatase, respectively), whose catalyzed reactions can easily be distinguished from each other by absorption spectrophotometry, with o-nitrophenyl-beta-galactoside and phenolphthalein monophosphate as substrates. Performance of this dual assay method compares well with that of conventional single-hapten enzyme-labeled assays, and results compare well with those by two single-hapten radioimmunoassays. The dual assay has certain advantages over single-hapten methods: smaller sample volume, lower reagent cost, and shorter overall assay time. As presented here, the use of enzyme labels to measure two (or more) haptens simultaneously represents a significant advance in the use of immunoassay techniques.

Effects of lucanthone on the sedimentation properties of DNA from HeLa cells

Exposure of HeLa cells to lucanthone (3 microgram/ml) caused dissociation of a fast-sedimenting duplex DNA complex, as judged by lysis and sedimentation in alkaline sucrose gradients. The effect of lucanthone on the DNA complex resembled that of actinomycin D and ionizing radiation. Protein synthesis inhibitors such as cycloheximide or inhibitors of DNA synthesis such as hydroxyurea did not lead to dissociation of the complex. Lucanthone was more active than were hycanthone and five other closely related thiaxanthenones tested. Lucanthone promoted X-ray-induced denaturation of DNA in intact cells, as judged by their nuclear immunoreactivity to antinucleoside antibodies. Lucanthone did not inhibit repair of X-ray-induced DNA single-strand breaks.