Bacterial adhesion to dental amalgam and three resin composites

OBJECTIVES

The ability of three oral bacteria to adhere to hydrophobic amalgam (water contact angle 60 degrees) and hydrophobic resin composites (Prisma-AP.H 56 degrees. Herculite XRV 82 degrees and Z100 89 degrees) was compared using an in vitro assay.

METHODS AND RESULTS

Following preincubation of the materials with human saliva, X-ray photoelectron spectroscopy showed the surfaces to adsorb carbon and nitrogen-containing compounds in a conditioning film that appeared to block the detection of Na and others in 2100 resin. Hg and Ag in amalgam, Si and Zn in Prisma AP.H resin and Ag and Na in Herculite resin. The precoating of the substrata by a proteinaceous conditioning film led to decreased binding of viable cells of Streptococcus sanguis CH3, Streptococcus salivarius HB and Actinomyces viscosus WG as compared with the adhesion to bare composites. With and without salivary coating, there was a correlation between increased bacterial hydrophobicity and increased retention on the substrata. However, there was no statistical difference in binding to the amalgam compared with the resin composites. In vitro studies showed that the bacteria autoaggregated in the presence of saliva.

CONCLUSION

The results indicate the potential ability of normal oral flora to colonize resin composite.

Serum levels of circulating anodic antigen and circulating cathodic antigen detected in mice infected with Schistosoma japonicum or S. mansoni

Serum concentrations of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were studied in mice infected with either Schistosoma japonicum or S. mansoni cercariae. Sera from uninfected mice were negative for both antigens. CAA was detectable in the S. japonicum-infected mice as early as at 2 weeks post-infection (p.i.), and levels were higher in these animals than in the S. mansoni-infected group during the full study period. At the moment of perfusion, 10 weeks p.i., a median of 9 and 29 worms, respectively, were recovered from the S. japonicum- and S. mansoni-infected mice, and the median CAA levels were 326 and 27 ng/ml, respectively. In contrast, CCA levels were much lower in the S. japonicum-infected group (27 ng/ml) as compared with the S. mansoni-infected mice (282 ng/ml). These results suggest an important difference between S. japonicum and S. mansoni infections in CAA and CCA production and/or clearance and indicate a significant role for CAA in the diagnosis of human schistosomiasis japonicum.

Attitudinal survey of adverse drug reaction reporting by medical practitioners in the United Kingdom

1. Attitudes of doctors to the Committee on Safety of Medicines' (CSM) adverse drug reaction (ADR) reporting scheme were investigated in order to assess their understanding of the purposes of the scheme and to identify reasons for failing to report suspected adverse drug reactions. 2. A postal questionnaire and letter of invitation were sent to 500 doctors who were randomly selected from the 1992 Medical Directory. A reminder letter and a second copy of the questionnaire were sent to non-responders after 4 weeks. 3. 284 (57%) responded to the questionnaire. Of these, 179 (63%) stated that they had previously reported an ADR to the CSM or a pharmaceutical manufacturer. 77% of general practitioners stated that they had reported one or more ADRs compared with 55% of hospital doctors. 4. Reasons for under-reporting included lack of time, lack of report forms and the misconception that absolute confidence in the diagnosis of an adverse reaction was important in the decision to send in a report. 5. An investigation of seven commonly proposed reasons for under-reporting showed that on the whole they did not apply. 6. Most doctors knew the types of reactions that the Committee on Safety of Medicines seeks reports for but only 38% knew the precise meaning of the Committee on Safety of Medicines' black triangle symbol. There also seemed to be confusion about some of the purposes of the adverse drug reaction reporting scheme. 7. The number of reporting doctors is much higher than has previously been estimated.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for calculus formation in patients with renal transplants

OBJECTIVE

To investigate the risk factors for stone formation in patients with functioning renal transplants in whom renal calculi develop.

PATIENTS AND METHODS

Renal calculi developed in six of 178 patients with functioning renal transplants under current review, an incidence of 3%. Risk factors for stone formation were investigated in five of these patients and compared with a randomly selected control group of 41 transplant patients with no stone problems.

RESULTS

Patients with transplant calculi typically passed smaller volumes of significantly more concentrated and alkaline urine with greater urinary excretion of uric acid (P < 0.05). Urine calcium excretion was also increased. Crystalluria was present in three of five stone formers compared with two of 25 controls. Overall, metabolic abnormalities included hypocitraturia (75%), hyperparathyroidism (36%), hypophosphataemia (24%) and hypercalcaemia (10%). Urinary infection was common (50%) and urinary output of magnesium and phosphate was at the lower end of normal for all patients.

CONCLUSION

These results suggest a multifactorial aetiology for stone formation in renal transplant recipients. Approaches to prevention and management are discussed.

Review of company postmarketing surveillance studies

OBJECTIVES

To review postmarketing surveillance studies sponsored by the pharmaceutical industry since the introduction of voluntary guidelines in 1987 and to evaluate their contribution to monitoring drug safety.

DESIGN

Retrospective analysis of the information submitted to the Medicines Control Agency on postmarketing surveillance studies.

SETTING

United Kingdom.

MAIN OUTCOME MEASURES

Study designs, projected and actual sample sizes, provision of interim and final reports, number of suspected serious adverse reactions reported, identification of new drug safety hazards.

RESULTS

31 studies had been conducted under the guidelines, of which 27 were prospective and four retrospective. Nine studies had at least one comparator group, the remainder were uncontrolled. The median projected sample size for the studies was 5600 patients. Only five studies had achieved at least 75% of the projected sample size. 11 studies had been abandoned, predominantly because of difficulties in recruitment, and 15 were ongoing. One study had identified an important new safety hazard.

CONCLUSIONS

Company postmarketing surveillance studies have made only a limited contribution to the assessment of drug safety, principally because of weak study designs and difficulties in recruitment. The guidelines require modification to take this experience into account.

Influence of dietary intakes of erythorbic acid on plasma vitamin C analyses

D-Erythorbic acid is an epimer of L-ascorbic acid, but lacks antiscorbutic activity. It is commonly used as a food additive, particularly in processed meat items. Except for high-performance liquid chromatography (HPLC) methodology, the commonly used analytical procedures to measure vitamin C do not distinguish between the two isomers. A study with seven adult women demonstrated that the concentration of erythorbic acid present in food items commonly consumed was sufficient to produce interference in plasma vitamin C analyses. With the meals used, 7-23% of the apparent vitamin C in plasma obtained 2 h after the ingestion of the meals was actually erythorbic acid when analyzed by HPLC. To avoid falsely high plasma-serum vitamin C values as a result of erythorbic acid ingestion, the analyses should be conducted on overnight fasting blood specimens or with the use of an HPLC-amperometric method.

Attempts to induce resistance in mice to Schistosoma japonicum and Schistosoma mansoni by exposure to crude schistosome antigens plus cloned glutathione-S-transferases

Several attempts have been made to induce resistance in mice to Schistosoma japonicum (Philippines) or Schistosoma mansoni by exposure to living male and/or female adult worms, their antigens or irradiated cercariae. No resistance was demonstrated in the following cases: re-exposure of mice to cercariae following praziquantel (PZQ) treatment of existing infection; re-exposure of mice following cyclosporin A (CsA) treatment at the time of first cercarial exposure; subcutaneous or intraperitoneal deposition of living male or female worms; repeated intranasal administration of crude worm homogenates plus Bordetella pertussis vaccine (BPV) as adjuvant. Homologous 60Co-irradiated cercariae were very effective at inducing resistance to infection with S. mansoni but not to infection with S. japonicum (Philippines) in a limited series of experiments. A regime of infection, immunization with homologous Escherichia coli-derived glutathione-S-transferases (GST), then PZQ treatment followed by homologous re-exposure did not result in significant resistance in either the S. mansoni or the S. japonicum (Philippines) systems. Mice given irradiated cercariae plus GST were not more resistant to subsequent S. mansoni infection than mice given irradiated cercariae alone. The results generally confirm and extend those reported by others with the conclusion that resistance to schistosomes in mice is difficult to achieve by exposure to adult worm antigens alone. Moreover, additional immunization with the GST available to date as cloned gene products, and injected in Freund's complete adjuvant, does not influence the outcome of exposure to crude worm antigens including any additive effects of protective irradiated cercariae.

Further studies on variable resistance of 129/J and C57BL/6 mice to infection with Schistosoma japonicum and Schistosoma mansoni

Two mouse strains maintained in this laboratory (WEHI) are variably resistant to infection with Schistosoma japonicum and S. mansoni in that worms cannot be found in the liver and portal system in a high proportion (WEHI 129/J mice) or low proportion (C57BL/6 mice) some weeks after exposure to cercariae. Resistance can be as high as 100% in WEHI 129/J mice and is usually around 20% in C57BL/6 mice. The proportion of resistant mice closely parallels the proportion of mice that demonstrate a shunting of microbeads, injected into a mesenteric vein, from liver to lungs. This applies to F1 x WEHI 129/J backcross mice in which the data suggest oligogenic genetic effects although no evidence for a participation of MHC-linked genes in the phenomenon has emerged. 129/J mice derived from the Jackson Laboratory do not show a shunting of beads from the portal system to the lungs but their progeny bred at WEHI do. Germ-free WEHI 129/J mice resemble conventionally-maintained, SPF-derived WEHI 129/J mice in their variable resistance to schistosome infection. No satisfactory explantation for hepato-portal system peculiarities in WEHI 129/J and C57BL/6 mice can be advanced as yet and a possibility raised in this paper is a contribution from nutritional factors such as hypervitaminosis A superimposed on a genetic predisposition in these two related mouse strains.

Studies on the sex ratio of worms in schistosome infections

Sex ratios of adult schistosomes in mice are almost invariably different from 1.0 and are biased towards males. The bias applies to wild rats infected with Schistosoma japonicum and trapped in an endemic area of the Philippines (male:female ratio = 1.7). It also applies to cercariae of snails collected in such areas and assessed by infection of laboratory mice using cercariae from individual snails (male:female ratio may approach 6.0). Experiments were designed to determine if duration of infection in the mammalian host was a factor that influenced the sex ratio of miracidia used for infecting snails and subsequently mice. BALB/c and C57BL/6 mice were infected with 100 cercariae of S. mansoni, and liver eggs harvested at early and late time points for infection of snails and production of cercariae. Two phenomena were demonstrated: firstly, a more pronounced male bias when eggs were harvested late compared with early in infection; secondly, a reduced apparent hatchability of eggs in BALB/c compared with C57BL/6 livers. The possibility is raised by the data that female miracidia within eggs of chronically infected individuals may be more prone to immune damage than male miracidia with important epidemiological consequences.

Cardiovascular, biochemical and hormonal changes during food-induced hypotension in chronic autonomic failure

The cardiovascular, biochemical and hormonal responses to a standard test meal have been investigated in patients with chronic autonomic failure and normal subjects. In autonomic failure there was a rapid (within 15 min), substantial and prolonged fall in blood pressure after the meal. A marked fall in blood pressure also occurred after a liquid meal of similar composition and caloric content, with no change in blood pressure in age-matched subjects with normal autonomic function. In autonomic failure after the test meal the blood pressure reached its nadir (45% fall) after 60 min, and had not returned to pre-meal levels after 3 h. There were no changes in cutaneous and forearm blood flow. In the normal subjects there were no changes in blood pressure after the meal; forearm blood flow fell and cardiac output increased. In autonomic failure there were no changes in plasma noradrenaline levels, unlike the normal subjects. Plasma adrenaline levels were unchanged in both groups. There was a similar rise in levels of plasma renin activity in both groups. The haematocrit and plasma osmolality did not change in either group. Changes in plasma glucose and plasma insulin levels were similar in both groups. The responses of 3 pancreatic gut peptides, neurotensin, pancreatic polypeptide and enteroglucagon, were greater in autonomic failure. Basal levels and responses of vasoactive intestinal polypeptide, cholecystokinin-8 and somatostatin were similar in both groups. The motilin response was greater in normal subjects. We conclude that in patients with autonomic failure there was a rapid, substantial and prolonged fall in blood pressure after a meal. This reduction in blood pressure was not counteracted by an increase in sympathetic nervous activity and other compensatory changes, as occur normally. It was unlikely that osmotic effects of the meal or gut secretions resulted in a significant loss of intravascular fluid into the gut. The fall in blood pressure probably results from vasodilatation within the splanchnic circulation, to which pancreatic and gastrointestinal hormones with vasodilatory actions may contribute.

The significance of stupor in the long-term outcome of chronic schizophrenia

The admission records of 271 long-stay chronic schizophrenic patients, resident in a large psychiatric hospital, were examined in order to identify those who had presented in stupor at the onset of their illness. Twelve patients were found (ten men and two women). When compared, in terms of current mental state and behaviour, with a similar sample of schizophrenics in whom stupor had been absent, significant differences between the two groups were detected, with those presenting in stupor demonstrating a less favourable outcome.

Differential blood pressure and hormonal effects after glucose and xylose ingestion in chronic autonomic failure

1. To investigate whether carbohydrate contributes to postprandial hypotension in autonomic failure, the cardiovascular, biochemical and hormonal effects of oral glucose and an iso-osmotic solution of oral xylose were studied on separate occasions in six patients with chronic autonomic failure. The effects of oral glucose were also studied in eight normal subjects. 2. In the patients oral glucose lowered blood pressure substantially (-34 +/- 7% at 60 min, area under curve -24.9 +/- 3.5%, P less than 0.001) and for a prolonged period (-25 +/- 4% at 120 min). Plasma noradrenaline levels did not change. In the normal subjects blood pressure was unchanged and plasma noradrenaline rose, suggesting a compensatory increase in sympathetic nervous activity. 3. In the patients xylose caused a smaller and more transient fall in blood pressure (-15 +/- 6% at 90 min, area under curve -8.9 +/- 4%, P less than 0.05) with a non-significant elevation in packed cell volume (36.7 +/- 1.8 to 38.2 +/- 1.8). It was therefore unclear if xylose was exerting osmotic effects within the bowel which contributed to the small blood pressure fall. Packed cell volume did not change in either the patients or normal subjects after glucose. 4. In the patients and normal subjects plasma insulin rose after glucose. Insulin levels were unchanged after xylose. Levels of pancreatic polypeptide and neurotensin, a potential vasodilator, rose in the patients only. The latter rose to a similar extent after both glucose and xylose, making it unlikely that neurotensin alone accounted for the hypotension. 5. These studies indicate that the carbohydrate components of a meal, and in particular those causing insulin release, contribute to postprandial hypotension in patients with autonomic failure.

Schistosoma mansoni and S. japonicum worm numbers in 129/J mice of two types and dominance of susceptibility in F1 hybrids

In a study on the genetics of resistance to schistosomiasis in WEHI 129/J mice, susceptibility to either Schistosoma mansoni or Schistosoma japonicum was shown to be unequivocally dominant in F1 hybrid crosses between genetically resistant WEHI 129/J and susceptible BALB/c mice. The operation of only 1 or 2 genes in the expression of resistance to S. mansoni was suggested by backcross analysis. Thus, approximately 25% of (BALB/c x WEHI 129/J) F1 x WEHI 129/J mice were resistant to S. mansoni infection, whereas resistance was manifest in approximately 50% of WEHI 129/J mice. The data are consistent with resistance being controlled by 1 recessive gene having 50% penetrance. We also report that 129/J mice obtained directly from the Jackson Laboratories (Bar Harbor, Maine) (designated JAX 129/J), differ from locally bred WEHI 129/J in being entirely susceptible to S. mansoni infection. However, both WEHI 129/J and JAX 129/J are relatively resistant to S. japonicum infection.

Development and implementation of a human accuracy program in patient foodservice

For many years, industry has utilized the concept of human error rates to monitor and minimize human errors in the production process. A consistent quality-controlled product increases consumer satisfaction and repeat purchase of product. Administrative dietitians have applied the concepts of using human error rates (the number of errors divided by the number of opportunities for error) at four hospitals, with a total bed capacity of 788, within a tertiary-care medical center. Human error rate was used to monitor and evaluate trayline employee performance and to evaluate layout and tasks of trayline stations, in addition to evaluating employees in patient service areas. Long-term employees initially opposed the error rate system with some hostility and resentment, while newer employees accepted the system. All employees now believe that the constant feedback given by supervisors enhances their self-esteem and productivity. Employee error rates are monitored daily and are used to counsel employees when necessary; they are also utilized during annual performance evaluation. Average daily error rates for a facility staffed by new employees decreased from 7% to an acceptable 3%. In a facility staffed by long-term employees, the error rate increased, reflecting improper error documentation. Patient satisfaction surveys reveal satisfaction, for tray accuracy increased from 88% to 92% in the facility staffed by long-term employees and has remained above the 90% standard in the facility staffed by new employees.

Angio-oedema and urticaria associated with angiotensin converting enzyme inhibitors

Images