Evaluation of donor arm disinfection techniques

BACKGROUND AND OBJECTIVE

To validate a standardized optimal national procedure for donor arm disinfection.

MATERIALS AND METHODS

A direct swabbing and plating technique was used to enumerate bacteria present on the arm pre- and postdisinfection. Twelve donor arm disinfection techniques were evaluated.

RESULTS

The Medi-Flex Adapted method, consisting of a two-stage process with an initial application of isopropyl alcohol followed by tincture of iodine, produced the best arm disinfection. A percentage reduction in bacterial counts of 99.79% (logarithmic reduction of 2.67) was obtained. Postdisinfection, 70% of donors had bacterial counts of zero, and 98% had counts of 10 or less.

CONCLUSION

The Medi-Flex disinfection method offers the English National Blood Service a validated, optimal 'best practice' disinfection technique and should contribute significantly to the reduction in risk of transmission of bacteria by transfusion.

The influence of two concentrations of sodium hypochlorite on human blood: changes in haemolysis, pH and protein

AIM

To evaluate the in vitro effect of 2.5% and 5.0% sodium hypochlorite (NaOCl) on human blood.

METHODOLOGY

Each concentration of NaOCl was reacted with human blood for 5 min at volume ratios of 1 : 1, 1 : 6, 1 : 12, each creating changes in colour, pH and temperature. Reaction suspensions were separated by centrifugation, and absorption measurements made for separated bilirubin, Fe, and protein supernatants. Each supernatant was desalted, lyophilized, and treated by SDS polyacrylamide gel electrophoresis (SOS-PAGE).

RESULTS

Increased ratios and concentrations of NaOCl caused an increase in both pH and temperature. Protein supernatants tended to decompose on SDS-PAGE. Supernatants showed increased decolourisation with 5.0% NaOCl. Concentrations of bilirubin, Ferrum and protein in supernatants decreased with increased NaOCl concentration. NaOCl had an effect on the protein component in blood.

CONCLUSIONS

These data suggest that changes in molecular structure are due to the chemical effects of NaOCl. Protein bands tended to show low molecular weight, suggesting that haemoglobin components effect the oxidation-reduction reaction.

[Electrochemical detoxication of the lymph in the treatment of patients with suppurative-resorptive endotoxicosis]

A new method for lymph detoxication in patients with pyoresorptive endotoxicosis is proposed. The method is based on electrochemical oxidation of the lymph, is simple and cheap. After 4-h exposure of the lymph with 0.04% sodium hypochlorite the concentration of the main toxic metabolites appreciably decreased, while the levels of total protein and leukocytes changed negligibly. Electrochemical detoxication of the lymph was used in the treatment of 13 patients with pyoresorptive endotoxicosis and led to improvement of the clinical status and rapid decrease in the levels of the major toxic metabolites, which was particularly expressed 3 days after the treatment. No negative effects were observed. Hence, electrochemical detoxication of the lymph appreciably improved the results of treatment of patients with cholestatic endotoxicosis.

Effect of exposing dentine to sodium hypochlorite and calcium hydroxide on its flexural strength and elastic modulus

AIM

The aim of this study was to evaluate the effect of sodium hypochlorite (NaOCl) solutions (3%, 5%) and saturated calcium hydroxide (Ca(OH)2) solution, individually and consecutively, on the flexural strength and modulus of elasticity of standardized dentine bars.

METHODOLOGY

Standardized plano-parallel dentine bars (n = 121) were divided into five test groups and one control group. The control group 1 consisted of dentine bars, stored in normal saline until testing. The dentine bars in the five test groups were treated by exposure to the following solutions; group 2--3% NaOCl, 2 h; group 3--5% NaOCl, 2 h; group 4--saturated Ca(OH)2 solution, 1 week; group 5--3% NaOCl, 2 h and then saturated Ca(OH)2 solution 1 week; group 6--5% NaOCl, 2 h and then saturated Ca(OH)2 solution 1 week. The dentine bars were then loaded to failure in a three-point bend test.

RESULTS

The data revealed a significant (P < 0.001) decrease in the modulus of elasticity and flexural strength of the dentine bars treated with 3% and 5% NaOCl. There was no significant difference in the flexural strength and the modulus of elasticity between the 3% and 5% NaOCl groups. Exposure to Ca(OH)2 significantly (P < 0.001) reduced the flexural strength but had no significant effect on the modulus of elasticity. The groups treated with sodium hypochlorite followed by calcium hydroxide did not have moduli of elasticity and flexural strengths that were significantly different from those treated only with sodium hypochlorite.

CONCLUSIONS

NaOCl (3 & 5%) reduced the modulus of elasticity and flexural strength of dentine. Saturated Ca(OH)2 reduced the flexural strength of dentine but not the modulus of elasticity. Sequential use of NaOCl and Ca(OH)2 has no additional weakening effect.

[Pharmacological and cost effectiveness bases of the use of categel and categel S [correction of F] in urological practice]

Preparations catedgel and catedgel S made in Austria (Montavit) was tried in Moscow hospital N 50. Categel is a sterile gel of methylcellulose with 2% lidocain and 0.05% chlorhexidine, catedgel S contains the same components but lidocain. Categel significantly reduces the risk of infectious-inflammatory complications after endourological manipulations, improves endoscopic diagnosis and makes some manipulations less painful. Comparative pharmacological cost-effect assessment of categel S and glycerine effects in prostatic transurethral resection. Categel was found 2.11 times more effective. It also improves quality of life of the patients. Categel can be recommended for wide use in urology.

Effect of sodium hypochlorite on mechanical properties of dentine and tooth surface strain

AIM

The aim of this study was to test the null hypothesis that sodium hypochlorite irrigation of root canals does not alter the properties of dentine and contribute to the weakening of root-treated teeth.

METHODOLOGY

The effect of two concentrations (0.5%, 5.25%) of sodium hypochlorite (NaOCl) and saline on (i) the elastic modulus and flexural strength of machined dentine bars, and (ii) changes in strain of 'whole' extracted human teeth were evaluated. One hundred standardized plano-parallel dentine bars (> 11.7 x 0.8 x 0.8 mm) were randomly divided into the three groups, immersed for 2 h in the respective solutions and then subjected to a three-point bend test. Changes in strain of each of 10 teeth on cyclical nondestructive occlusal loading were measured using electrical resistance strain gauges bonded to the cervical aspects. Each tooth had its crown and enamel reduced and root canal prepared. These were irrigated sequentially in a series of four separate, 30-minute regimes; initial-saline, 0.5% NaOCl, 5.25% NaOCl and final-saline. The changes in strains after each irrigation regime were compared.

RESULTS

There was a significant decrease in elastic modulus of the dentine bars immersed in 5.25% NaOCl compared with the saline group (P < 0.01). There was also a significant decrease in flexural strength of the dentine bars in the 5.25% NaOCl group compared to both the saline and 0.5% NaOCl groups (P < 0.01). The strain data from the nondestructive tooth loading tests revealed significant increases in tensile strain between the initial-saline and the final-saline stages (P < 0.01). Significant increases in compressive strains were also found between initial-saline and 5.25% NaOCl; and between 0.5% NaOCl and 5.25% NaOCl stages (P < 0.01).

CONCLUSIONS

The null hypothesis was rejected, 5.25% NaOCl reduced the elastic modulus and flexural strength of dentine. Irrigation of root canals of single, mature rooted premolars with 5.25% NaOCl affected their properties sufficiently to alter their strain characteristics when no enamel was present.

Alcohol as a gastric disinfectant? The complex relationship between alcohol consumption and current Helicobacter pylori infection

Alcoholic beverages have antimicrobial effects against Helicobacter pylori in vitro. To elucidate the relation between alcohol consumption and current infection with H. pylori in vivo, we carried out a pooled analysis of three recent studies from Southern Germany, comprising 1410 adults age 15 to 69. Detailed information on consumption of various alcoholic beverages was collected through standardized questionnaires. Helicobacter pylori infection was measured by 15C-urea breath test. Overall, prevalence of current H. pylori infection was lower among subjects who consumed alcohol (34.9%) than among nondrinkers (38.0%). The adjusted odds ratio was 0.79, with a 95% confidence interval of 0.58-1.08. Furthermore, alcohol consumption showed a strong inverse relation to the result of the 13C-urea breath test, a semiquantitative measure of the bacterial load, among infected subjects. The inverse association between alcohol consumption and H. pylori infection was not monotonic, however. Odds of infection were lowest at moderate levels of alcohol consumption and increased at higher levels of alcohol consumption, regardless of the type of alcoholic beverages consumed. These results support the hypothesis that moderate alcohol consumption may favor suppression and eventual elimination of H. pylori infection. At higher levels of alcohol consumption, the antimicrobial effects of alcoholic beverages may be opposed by adverse systemic effects of drinking, such as adverse effects on the immune defense.

[Indirect electrochemical oxidation of blood plasma in combined treatment of patients with acute mediastinitis]

Treatment results in 61 patients with acute mediastinitis are analyzed. Combined treatment of acute mediastinitis, including cryoplasma-antienzymic complex use and indirect electrochemical blood plasma detoxication, promotes disappearance of microcirculation disorders, to earlier decreasing of endogenic intoxication, outcomes improvement.

Two-Week (Ten-Day) Inhalation Toxicity and Two-Week Recovery Study of Phenol Vapor in the Rat

The toxicity of phenol vapor was evaluated in male and female Fischer 344 rats (20/sex/group) via flow-past nose-only inhalation exposure. The test animals were exposed to target concentrations of 0 (air control), 0.5, 5.0, or 25 parts per million (ppm) of phenol in air for 6 hours/day, 5 days/week, for 2 weeks. High pressure liquid chromatography (HPLC) measurement of phenol test atmospheres determined mean (+/- standard deviation) analytical concentrations of 0.0 +/- 0.0, 0.52 +/- 0.078, 4.9 +/- 0.57, and 25 +/- 2.2 ppm, respectively. After 2 weeks of exposure, 10 test animals/sex/group were sampled for clinical chemistry and hematology parameters, and then sacrificed. Histopathological examination included the nasopharyngeal tissues, larynx, trachea, lungs with mainstem bronchi, kidney, liver, and spleen. The remaining 10 animals/sex/group were retained for a 2-week recovery period. Recovery groups of animals were evaluated as described previously and then sacrificed. No signs of toxicity in clinical observations (including overt neurological signs), body weights, food consumption, clinical pathology, organ weights, macroscopic pathology or microscopic pathology were seen during the exposures or at either sacrifice interval. In conclusion, 2-week inhalation exposures to phenol vapor at concentrations up to and including 25 ppm did not produce any adverse effects.

Chronic toxicity of chloroform to Japanese medaka fish

Japanese medaka (Oryzias latipes) were continually exposed in a flow-through diluter system for 9 months to measured chloroform concentrations of 0.017, 0.151, or 1.463 mg/L. Parameters evaluated were hepatocarcinogenicity, hepatocellular proliferation, hematology, and intrahepatic chloroform concentration. Histopathology was evaluated at 6 and 9 months. Chloroform was not hepatocarcinogenic to the medaka at the concentrations tested. Chronic toxicity was evidenced at these time points by statistically significant ([alpha] = 0.05) levels of gallbladder lesions and bile duct abnormalities in medaka treated with 1.463 mg/L chloroform. We assessed hepatocellular proliferation by exposing test fish to 5-bromo-2'-deoxyuridine in the aquarium water for 72 hr after 4 and 20 days of chloroform exposure; we then quantified area-labeling indices of the livers using computer-assisted image analysis. We observed no treatment-related increases in cellular proliferation. We analyzed cells in circulating blood in medaka after 6 months of chloroform exposure. Hematocrit, leukocrit, cell viability, and cell counts of treated fish were not significantly different from those of control fish. Using gas chromatography (GC), we evaluated intrahepatic concentrations of chloroform in fish after 9 months of exposure. Livers from the 0.151 and 1.463 mg/L chloroform-treated fish had detectable amounts of chloroform, but these levels were always lower than the aquaria concentrations of chloroform. Thus, it appeared that chloroform did not bioaccumulate in the liver. Unidentified presumptive metabolite peaks were found in the GC tracings of these fish livers.

Toxicokinetics of bromodichloroacetate in B6C3F1 mice

The oral and i.v. elimination kinetics were investigated for bromodichloroacetate (BDCA), a haloacetate found in drinking water. The BDCA was administered at a dose of 5, 20 and 100 mg kg-1 to B6C3F1 mice and appears to distribute to the total body water with a mean volume of distribution of 427 +/- 79 ml kg-1. It is subject to first-pass hepatic metabolism with a range of bioavailabilities of 0.28-0.73. A mean terminal half-life of 1.37 +/- 0.21 h. was calculated from the two lower doses of both i.v. and oral administration. Non-linear behavior was exhibited at doses greater than 20 mg kg-1, with a much higher than expected area under the curve (AUC), a decrease in total body clearance (CL(b)) and an increase in the terminal half-life to 2.3 h at the highest dose. The average CL(b) was 220 ml h(-1) kg-1 for the lower two doses but decreased to 156 ml h(-1) kg-1 at the high dose. The BDCA is primarily eliminated by metabolism, with only 2.4% of the parent dose being recovered in the urine at the high dose. The unbound renal clearance, as calculated from the high dose, was 15.0 ml h(-1) kg-1. The BDCA is moderately bound to plasma proteins (f(u) = 0.28) and preferentially distributes to the plasma with a blood/plasma ratio of 0.88.

Diathermy and alcohol skin preparations - a potential disastrous mix

Disinfectant solutions with high concentrations of alcohol are used in many operating theatres as skin preparation. We present two cases of burns as a result of accidental ignition of the solution and list precautionary measures for the use of these solutions.

Influence of the drinking water disinfection by-product dibromoacetic acid on rat estrous cyclicity and ovarian follicular steroid release in vitro

The drinking water disinfection by-product, dibromoacetic acid (DBA) has been reported to affect gonadal functions in the male rat. However, there is little information regarding the influence of DBA on female reproductive activity. Consequently, the present study investigated the effects of DBA on estrous cyclicity and the impact in vitro of DBA on ovarian follicular steroid secretion. Regularly cycling animals were dosed with DBA (0 to 270 mg/kg/day) for 14 days and estrous cyclicity was monitored during treatment and for an additional 2-week posttreatment interval. A dose-related alteration in cyclicity was observed at 90 and 270 mg/kg/day, which persisted through the posttreatment monitoring in the high dose group. An in vitro exposure of preovulatory follicles to DBA was then used to assess the influence of DBA on steroid release. To select a concentration for use, a single oral exposure to 270 mg/kg was administered, and the mean blood levels were determined over a 5-h interval. For this in vitro work, pairs of preovulatory follicles from PMSG-primed immature rats were exposed to 0 or 50 microg/mL DBA over a 24-h period and evaluated for estradiol and progesterone release under baseline and hCG-stimulated conditions. The influence of tumor necrosis factor (TNFalpha) exposures under these conditions was also determined. In the nonstimulated condition, DBA was found to increase the release of estradiol, but had no detectable effect in response to hCG. Progesterone, however, showed marked suppression under hCG stimulation following exposure to DBA, while nonstimulated secretion was unaffected. TNFalpha by itself also suppressed stimulated progesterone release, but had no additional effect in combination with DBA. The data suggest that one factor in the disruption in estrous cyclicity could be an alteration in steroid production, which was characterized by separate effects on both estradiol and progesterone secretion.

Laryngeal and hypopharyngeal cancers and occupational exposure to formaldehyde and various dusts: a case-control study in France

OBJECTIVES

A case-control study was conducted in France to assess possible associations between occupational exposures and squamous cell carcinomas of the larynx and hypopharynx.

METHODS

The study was restricted to men, and included 201 hypopharyngeal cancers, 296 laryngeal cancers, and 296 controls (patients with other tumour sites). Detailed information on smoking, alcohol consumption, and lifetime occupational history was collected. Occupational exposure to seven substances (formaldehyde, leather dust, wood dust, flour dust, coal dust, silica dust, and textile dust) was assessed with a job exposure matrix. Exposure variables used in the analysis were probability, duration, and cumulative level of exposure. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were estimated by unconditional logistic regression, and were adjusted for major confounding factors (age, smoking, alcohol, and when relevant other occupational exposures).

RESULTS

Hypopharyngeal cancer was found to be associated with exposure to coal dust (OR 2.31, 95% CI 1.21 to 4.40), with a significant rise in risk with probability (p<0.005 for trend) and level (p<0.007 for trend) of exposure. Exposure to coal dust was also associated with an increased risk of laryngeal cancer (OR 1.67, 95% CI 0.92 to 3.02), but no dose-response pattern was found. A significant relation, limited to hypopharyngeal cancer, was found with the probability of exposure to formaldehyde (p<0.005 for trend), with a fourfold risk for the highest category (OR 3.78, 95% CI 1.50 to 9.49). When subjects exposed to formaldehyde with a low probability were excluded, the risk also increased with duration (p<0.04) and cumulative level of exposure (p<0.14). No significant association was found for any other substance.

CONCLUSION

These results indicate that exposure to formaldehyde and coal dust may increase the risk of hypopharyngeal cancer.

[Sodium hypochlorite in the treatment of the suppurative-septic complications in patients with strangulated hernias]

The article presents an analysis of surgical treatment of 2155 patients with incarcerated hernias of the anterior abdominal wall. Pyo-septic complications took place in 24.3%. A comparison of results of treatment by traditional methods with those using solution of sodium hypochlorite (indirect electrochemical oxidation of blood) has shown that in the group of patient treated with sodium hypochlorite lethality was reduced from (18.8 +/- 0.2)% to (11.2 +/- 0.2)%, the amount of suppuration of the operative wound was 1.8 times less and the average number of bed-days was (4.5 +/- 0.2) less.

Skin tolerance and effectiveness of two hand decontamination procedures in everyday hospital use

BACKGROUND

Hand decontamination is crucial to control nosocomial infections. The utility of hand decontamination is related not only to its antimicrobial effectiveness, but also to its acceptability by hospital staff.

OBJECTIVES

We aimed to assess skin tolerance and antimicrobial effects of two widely accepted hand hygiene measures under in-use conditions.

METHODS

Fifty-two nurses were randomly assigned for an 8-day period to either an alcohol-based disinfectant or a hand wash with a non-antiseptic soap. At baseline and at the end of the test period, microbiological hand samples were obtained both before and after a hand hygiene procedure, and skin tolerance was assessed using clinical scores and measurement of transepidermal water loss.

RESULTS

Self-assessment of skin condition and grade of skin damage worsened significantly more in the group using soap than in the group using alcoholic disinfectant (P = 0.004 and P = 0.01, respectively). The alcohol-based rinse was significantly more effective than liquid soap in removing transient contaminant micro-organisms (P = 0.016). Twenty of 50 hand washes with non-antiseptic soap apparently resulted in bacterial contamination of the hands. At the end of the study, the total bacterial count increased with the increasing number of hand washes in the soap group (P = 0.003), and with the degree of skin damage (P = 0.005) in the antiseptic group.

CONCLUSIONS

In everyday hospital practice, alcohol-based disinfectant is more effective and better tolerated than non-antiseptic soap; soap is at risk of spreading contamination; and skin comfort strongly influences the number and the quality of hand hygiene procedures.

Activation of peripheral NMDA-nitric oxide cascade in formalin test

BACKGROUND

It has been suggested that peripheral glutamate and nitric oxide (NO) released by tissue-damaging stimuli play an important role in peripheral nociceptive transmission. This study was conducted to determine whether NO was released in the periphery after subcutaneous injection of formalin and whether the peripheral N-methyl-d-aspartate (NMDA)-NO cascade was activated.

METHODS

During pentobarbital anesthesia, a microdialysis probe was implanted subcutaneously into the glabrous skin of both hind paws of Sprague-Dawley rats. After sample collection to obtain the basal level of NO metabolites (total amount of nitrite [NO2-] and nitrate [NO3-] [NO2--NO3-]), 5% formalin was injected into the plantar surface of the right hind paw during perfusion of the dialysis catheters with artificial cerebrospinal fluid (ACSF), the NO synthase inhibitor NG-monomethyl-L-arginine acetate, or the NMDA antagonist D,l-2-amino-5-phosphonovaleric acid through a microdialysis probe. Formalin also was injected in the animals that underwent sciatic nerve sectioning. In another series of experiments, NMDA was perfused through one probe. Samples for measurement of NO2--NO3- were collected and immediately analyzed using high-performance liquid chromatography.

RESULTS

Subcutaneous formalin significantly increased the dialysate concentrations of NO2--NO3- (maximum increase 144 +/- 12% of baseline value 30 min after formalin administration; P < 0.05) on the side ipsilateral to the injection. Both NG-monomethyl-l-arginine acetate and D, l-2-amino-5-phosphonovaleric acid significantly (P < 0.05) suppressed the formalin-induced increases in NO2--NO3- concentration. In the rats with denervation of the sensory nerves, formalin did not change the NO2--NO3- concentration. In addition, NMDA perfusion significantly (P < 0.05) increased the concentrations of NO2--NO3-.

CONCLUSION

The results of the current study show that subcutaneous formalin injection induces peripheral release of NO, the production of which is mediated by activation of NMDA receptors in the peripheral nervous system.

Antiseptic skin preparation revisited

Preparing the operation site by painting a solution of something onto the skin is one of the best preserved rituals in surgery. There appears to be something really satisfying about this precursor to the main event, and if the solution used is brightly coloured, or stains the skin, then so much the better--you can actually see where you've been! I hope than no-one is under the illusion that because the whole leg (or arm, or abdomen or anywhere else) is now a sickly shade of brown or alarmingly pink, that no pathogenic organisms can possibly have survived the onslaught. In this comprehensive review of the literature and practice audit, Sally Kent revisits the reasons for skin preparation, and recommends the use of well proven research to determine correct practice.

The reculture technique: individualizing the treatment of Acanthamoeba keratitis

PURPOSE

To assess the efficacy of three drugs in different concentrations against different strains of Acanthamoeba using the reculture technique.

METHODS

Cysts and trophozoites were immersed in five separate solutions. The solutions administered included 0.1% and 0.02% polyhexamethylene biguanide (PHMB), 0.1% and 0.02% chlorhexidine, and propamidine isethionate (Brolene). Readings took place after 1, 5, and 24 hours. The cysts and trophozoites were then recultured for an additional period of 48 hours. An effective drug was defined as a medication that inhibited any growth of trophozoites using the reculture technique.

RESULTS

Chlorhexidine at concentrations of 0.1% and 0.02% was the only effective drug against all five strains of Acanthamoeba examined, and no trophozoites were detected on plates immersed with this agent. Only 0.1% chlorhexidine was effective in destroying all cysts in the five strains examined.

CONCLUSION

We found that 0.02% chlorhexidine was efficient in irradicating all trophozoites and 0.1% chlorhexidine was effective in eradicating all cysts in the samples we examined. Therefore, it may be possible that 0.02% chlorhexidine is a good initial treatment in amoebic keratitis. Sensitivity testing, then, may be performed using the reculture technique and specification of therapy can be made accordingly.