Cytopathologic effects of chlorhexidine on human cells

Exposure of human cells in culture to chlorhexidine at concentrations equal to or greater than 0.004% resulted in impaired cellular function and/or cell death. Release of membrane bound 51Cr, inhibition of protein synthesis as measured by incorporation of 3H-leucine into protein-like material, and staining by trypan blue were seen as sequellae to exposure to 0.006% chlorhexidine for 3 hours. Lower doses were capable of inhibiting protein synthesis and releasing 51Cr, but did not result in staining of cells by trypan blue. Exposure of cells to 0.2% chlorhexidine for 30 seconds produced maximal suppression of protein synthesis and release of 51Cr.

Randomised trial of ganciclovir and acyclovir in the treatment of herpes simplex dendritic keratitis: a multicentre study

AIMS

This study was designed to assess the relative efficacy of topical ganciclovir 0.15% gel and acyclovir 3% ointment in the treatment of herpes simplex dendritic keratitis.

METHODS

Both treatment modalities were administered on a five times daily basis to patients suffering from herpes simplex keratitis. Patients were assigned randomly to one of the two treatment groups for the purpose of the trial. They were then examined on days 2, 7, 10, and 14 to assess the rate of healing of the dendritic ulceration.

RESULTS

There was no statistically significant difference detected in the rate of healing between the two treatment groups over the course of the trial.

CONCLUSIONS

Review of the relative efficacy of topical ganciclovir and acyclovir in the treatment of herpes simplex dendritic keratitis showed that both treatment modalities were equally effective in their ability to heal the viral induced corneal ulceration. There were no significant side effects or adverse effects reported for either treatment modality.

Hemostatic effects of stress hormone infusion

BACKGROUND

Surgery causes changes in hemostasis, leading to a hypercoagulable state. This postoperative increase in hemostatic function is attenuated in patients receiving regional anesthesia compared with those receiving general anesthesia. Regional anesthesia also decreases the neuroendocrine response to surgery compared with general anesthesia, and this effect is hypothesized to be responsible for the differences in hemostatis. To test the hypothesis that neuroendocrine hormones cause changes in hemostasis, we infused stress hormones into normal volunteers and measured hemostatic function.

METHODS

After drug screening, 12 normal volunteers were studied. On two admissions, volunteers randomly received either stress hormone (epinephrine, cortisol, or glucagon) or placebo infusion for 24 h. During infusion, patients remained at bed rest and received controlled meals. Blood was obtained from indwelling venous catheters before infusion and 2, 8, and 24 h after the start of infusion. Blood was analyzed for neuroendocrine hormone concentrations, glucose, complete blood count, coagulation proteins, platelet reactivity, and activity of the fibrinolytic system.

RESULTS

In the stress hormone group, concentrations of epinephrine, norepinephrine, cortisol, glucagon, and insulin were increased during the infusion period compared with those in the placebo group. Glucose concentrations and white blood cell counts were increased in the stress hormone group compared with those in the placebo group. Circulating fibrinogen concentrations increased 30% and ex vivo collagen-induced platelet reactivity increased 123% (aggregation) and 103% (dense granule release) in the stress hormone infusion group, whereas there was no change in the placebo group. Fibrinolytic proteins were similar in both groups, demonstrating a decrease in plasminogen activator inhibitor-1 activity at 8 and 24 h (196% in the hormone group vs. 199% in the placebo group).

CONCLUSIONS

Infusion of stress hormones to concentrations found during surgery is safely tolerated and causes metabolic changes observed with surgery. Stress hormone infusion increases ex vivo platelet reactivity and fibrinogen concentrations that resemble changes seen postoperatively but does not recreate the postoperative decrease in fibrinolytic activity. Differences in neuroendocrine response between types of anesthesia may explain some postoperative changes in platelet function and acute phase reactivity, but additional uncharacterized factors are responsible for the differences in fibrinolysis.

Ganciclovir ophthalmic gel in herpes simplex virus rabbit keratitis: intraocular penetration and efficacy

A chronic administration of three ganciclovir gels (0.2%, 0.05%, 0.0125%) was compared with a placebo gel and a 3% acyclovir ophthalmic ointment in the treatment of HSV-1 rabbit keratitis. All the ganciclovir gels showed a clinical efficacy: a significant reduction of the corneal ulcer area, clouding and vascularization (p < 0.05) and a fast inhibition of HSV isolates into tear film with the 0.2% and 0.05% ganciclovir gels. However the efficacy was slower than using acyclovir ointment. No significant difference could be shown between the 0.2% and 0.05% ganciclovir gels or the 0.05% ganciclovir gel and the acyclovir treatment on viral isolation, when it was performed on pooled samples. The distribution of ganciclovir and acyclovir into the rabbit eyes (HPLC methods), were similar but markedly higher in solid tissues than ocular fluids. It might explain the recovery from tissue damages. The mean corneal ganciclovir concentrations were largely higher than ED 50 of ganciclovir for HSV-1. No toxicity was expected, due to very limited systemic availability. This study suggests a comparable activity on HSV-1 superficial keratitis between 0.05%, 0.2% ganciclovir gels and 3% acyclovir ointment. Higher concentration of ganciclovir gels are probably necessary in order to treat the HSV-1 kerato-uveitis.

Optimization of the resistance of arterial allografts to infection: comparative study with synthetic prostheses

Arterial allografts can be used for in situ treatment of prosthetic graft infection. The purpose of this in vitro study was to compare the resistance of allografts and synthetic prostheses to infection by five strains of bacteria and to study antibiotic treatments designed to reduce allograft infection. Fresh and cryopreserved allografts were compared with synthetic prostheses made of various biomaterials including PTFE, plain Dacron, gelatine-sealed Dacron, and gelatine-sealed, rifampicine-bonded Dacron. Allografts were used with or without treatment using an antibiotic containing gentamycine, lincomycine, and vancomycine. The bacterial strains tested were Escherichia coli, Staphylococcus aureus, slime-producing Staphylococcus epidermidis, non-slime-producing Staphylococcus epidermidis, and Pseudomonas aeruginosa. Infection was evaluated by counting the number of adherent bacteria on the allograft or synthetic material after rinsing and ultrasonication. Statistical analysis was achieved using nonparametric Mann-Whitney tests. Results showed that allografts not treated with antibiotics were highly susceptible to bacterial infection. Antibiotic treatment decreased infection. Application of antibiotic after thawing cryopreserved allografts led to a significant decrease. None of the biomaterials tested provided sufficient protection against bacteria resistant to the antibiotics used.

Effects of topical anaesthetics and fluorescein on the real-time PCR used for the diagnosis of Herpesviruses and Acanthamoeba keratitis

BACKGROUND

The early microbiological diagnosis of corneal infections may prevent the condition from worsening.

AIM

To study the potential interferences of oxybuprocain and fluorescein solutions used by ophthalmologists on the performances of the real-time polymerase chain reaction (PCR) carried out as routine test for diagnosis of keratitis.

METHODS

Quantified suspensions of Herpes simplex virus (HSV1), Varicella zoster virus (VZV), Cytomegalovirus (CMV) and Acanthamoeba with and without oxybuprocain or fluorescein added before DNA extraction were tested by real-time PCR.

RESULTS

The capacities of the real-time PCR to detect HSV, VZV, CMV and Acanthamoeba were reduced by oxybuprocain and fluorescein. Both products diluted to 1/16 reduced the PCR detection capacities for more than 2 logs (DNA copies/sample).

CONCLUSIONS

The simultaneous introduction of fluorescein or topical anaesthetics into the tubes containing the specimens to be tested by PCR may lead to false negative results. Because corneal specimens for microbiological diagnosis of keratitis are obtained after topical administration of anaesthetics and corneal staining with fluorescein, ophthalmologists should be aware to rinse the eye surface intensively with appropriate eye solutions to minimise the risks of misdiagnosis.

Hand function following single ray amputation

We retrospectively studied primary and reconstructive single ray resection at 16 to 150 months after surgery (median, 41 months) in 25 patients (18 males) whose average age was 28 years. Cases were reviewed 16 to 154 months after surgery (median, 41 months). The injuries involved 14 dominant and 11 nondominant hands. Twelve patients had primary ray resection (< or =2 weeks after injury) and 13 had secondary/reconstructive amputation of 18 border and 7 central digits. Examinations and functional testing by Minnesota rate of manipulation and timed grooved pegboard tests were done and x-rays were reviewed. The majority of patients were subjectively satisfied with the appearance and function of the hand. Patients lost an average of 13 weeks of work (range, 2-24 weeks); those with primary resection were out of work 9 weeks (range, 2-17 weeks) and patients who had secondary resection lost a total of 16 weeks of work (range, 7-24 weeks). Twenty-one of the 25 patients returned to their preinjury occupation. Evaluation of nonwork plus settled workers' compensation cases versus nonsettled compensation/litigation cases showed that there were statistically significant differences in grip strength, key pinch, oppositional pinch, and Minnesota rate of manipulation test results. Primary ray removal limits the total costs associated with injury and disability; unsettled compensation/litigation issues produce statistically disparate and otherwise physically inexplicable differences.

Detection by broad-range real-time PCR assay of Chlamydia species infecting human and animals

BACKGROUND

Tests available for molecular diagnosis of chlamydial infections detect Chlamydiatrachomatis, but do not find other Chlamydia species associated with genital, ophthalmic, cardiovascular, respiratory or neurological diseases. The routine detection of all Chlamydia species would improve the prognosis of infected people and guide therapeutic choices.

AIM

To design and validate a sensitive, specific, reproducible, inexpensive and easy-to-perform assay to quantify most Chlamydia species.

METHODS

Primers and probe were selected using the gene coding for the 16S rRNA. The detection limits were assessed for suspensions of Chlamydia trachomatis, Chlamydia psittaci and Chlamydia pneumoniae. The performance of this test was compared with that of two commercial kits (Amplicor-Roche and Artus) on 100 samples obtained from children with trachoma.

RESULTS

The detection capacities for Chlamydia trachomatis of the broad-range real-time polymerase chain reaction (PCR) were similar or slightly better than those obtained with commercial kits (0.2 copies of DNA/microl). Only the broad-range PCR identified specimens containing Chlamydia psittaci and Chlamydia pneumoniae. The commercial kits and the broad-range assay detected Chlamydia species in 5% and in 11%, respectively, of samples from children with trachoma.

CONCLUSIONS

This new real-time PCR offers a sensitive, reproducible assay that produces results in <3 h. With panels of quantified Chlamydia species, this real-time PCR can be run with all real-time PCR equipment. Larger trials are needed to confirm the utility of this test in diagnosis and for therapeutic follow-up.

Machine Learning for Health: Algorithm Auditing & Quality Control

Developers proposing new machine learning for health (ML4H) tools often pledge to match or even surpass the performance of existing tools, yet the reality is usually more complicated. Reliable deployment of ML4H to the real world is challenging as examples from diabetic retinopathy or Covid-19 screening show. We envision an integrated framework of algorithm auditing and quality control that provides a path towards the effective and reliable application of ML systems in healthcare. In this editorial, we give a summary of ongoing work towards that vision and announce a call for participation to the special issue  Machine Learning for Health: Algorithm Auditing & Quality Control in this journal to advance the practice of ML4H auditing.

Microbiological efficacy of 3-day treatment with azithromycin 1.5% eye-drops for purulent bacterial conjunctivitis

PURPOSE

Antibacterial efficacy of topically applied azithromycin 1.5% was compared with tobramycin 0.3% in a multicenter, randomized, investigator-masked study for the treatment of purulent bacterial conjunctivitis.

METHODS

A total of 1043 adults and children received either azithromycin twice daily for 3 days (n=524) or tobramycin every 2 hours while awake for 2 days, then four times daily for 5 days (n=519). Conjunctival swabbing was taken at days 0, 3, and 9, using alginate swabs resuspended in a dissolution-transport medium, providing rapid and reproducible results. Cagle's criteria were used to define the pathogenicity level for each isolated bacterium.

RESULTS

In the per-protocol set, the rate of bacteriologic resolution was 85.2% for azithromycin versus 83.8% for tobramycin on day 3, and 92.8% for azithromycin versus 94.6% for tobramycin on day 9. Azithromycin was demonstrated to be noninferior to tobramycin according to the 10% noninferiority margin. Although some bacteria were categorized as resistant to tested antibiotics, eradication was observed (for azithromycin: Acinetobacter, Enterobacteriaceae, Pseudomonas), highlighting the specific pharmacokinetics/pharmacodynamics of the ocular route.

CONCLUSIONS

In total, topical therapy with azithromycin 1.5% administered only twice daily for 3 days effectively eradicates most pathogenic bacteria associated with bacterial conjunctivitis. These microbiologic results are in accordance with the observed clinical outcome. This new anti-infective product has the advantage of a short treatment course which could lead to an improvement in patient compliance.

Mass treatment of trachoma with azithromycin 1.5% eye drops in the Republic of Cameroon: feasibility, tolerance and effectiveness

Aims

An epidemiological study carried out in 2006 indicated a high prevalence of blinding trachoma in the Kolofata Health District, Far North Region, Republic of Cameroon. As a result, the national blindness control programme of Cameroon instituted a trachoma elimination programme using the SAFE strategy.

Methods

A campaign to treat the entire district population with azithromycin 1.5% eye drops was undertaken in February 2008. To measure the effectiveness of treatment on the prevalence of active trachoma, two epidemiological studies were conducted on a representative sample of children aged between 1 and 10 years. The first study was performed just prior to the treatment campaign and the second study was performed 1 year later.

Results

The prevalence of active forms of trachoma (trachomatous inflammation—follicular (TF) + TF/trachomatous inflammation—intense (TI)) dropped from 31.5 (95% CI 26.4 to 37.5)% before treatment to 6.3 (95% CI 4.1 to 9.6)% 1 year after treatment—a reduction of nearly 80%. There were no reports of serious or systemic side effects. Tolerance was excellent and no treatment was interrupted.

Conclusion

Mass treatment with azithromycin 1.5% eye drops is feasible, well tolerated and effective.

Cyanoside chloride and chromocarbe diethylamine are more effective than vitamin C against exercise-induced oxidative stress

Exercise generates free radicals only when it is exhaustive. Free radicals are involved in tissue damage caused by exercise. Antioxidant vitamins (vitamin C and E) and other antioxidants such as coenzyme Q, and N-acetyl cysteine prevent muscle damage and decrease muscle fatigue. The main aim of this paper was to test the possible protective effect of two new antioxidants, cyanoside chloride and chromocarbe diethylamine, on the oxidative stress generated by exhaustive exercise. The antioxidants were given to rats daily (50 mg/kg) in drinking water for 30 days. Blood oxidized glutathione/ reduced glutathione ratio, and plasma malondialdehyde levels were determined as indexes of oxidative stress. Plasma creatine kinase, alanine-aminotransferase and lactate dehydrogenase activities were used as markers of muscle damage. Both cyanoside chloride and chromocarbe diethylamine were more effective than vitamin C in the prevention of glutathione oxidation in blood. Furthermore, cyanoside chloride and chromocarbe diethylamine partially prevented muscle damage. Chromocarbe diethylamine was the most effective compound in the prevention of exercise-induced lipid peroxidation (malondialdehyde) in plasma.

New tool for the simultaneous detection of 10 different genotypes of Acanthamoeba available from the American Type Culture Collection

BACKGROUND

Acanthamoeba keratitis (AK) is a sight-threatening infection, and none of the current diagnosis tests are able to detect in one reaction low levels of the vast majority of strains associated with pathology. The goal of this work was to validate a new tool for the detection of the American Type Cell Collection (ATCC) referenced Acanthamoeba monitoring simultaneously DNA extraction yields and PCR inhibitors. Performances were assessed on corneal scrapings.

METHODS

Primers were selected in a region bracketing a 41 591 bp of the A castellanii mitochondrion gene. DNA extraction and PCR inhibitors were monitored by adding an internal control (virus). Acanthamoeba were detected and quantified by the real-time fast-duplex TaqMan PCR (f-d-real-t PCR) and negativity confirmed by SYBR Green real-time PCR.

RESULTS

The f-d-real-t PCR detects 0.1 cyst/microl or less of the 10 referenced strains (sensitivity slightly lower for A astronyxis). Bacteria, fungi and herpesviruses do not cross-react. The specificity and sensitivity of the f-d-real-t PCR were higher than culture and other real-time PCR on 20 keratitis samples.

CONCLUSION

The f-d-real t PCR detects in less than 2 h the Acanthamoeba strains available from the ATCC with a higher sensitivity and specificity than techniques previously reported. Larger trials are necessary to validate its usefulness for disease management and environmental studies.

Tolerance to or facilitation of pharmacological effects induced by chronic treatment with the beta-adrenergic stimulant clenbuterol

The effect in mice of chronic administration of the beta-adrenergic agonist clenbuterol was studied using four pharmacological tests, two of which are predictive of antidepressant activity in man. The suppressive effect of acute administration of the beta-adrenergic agonist in two tests unrelated to antidepressant activity, locomotor activity and investigation of food, was attenuated after chronic treatment. However, in the two tests which are predictive of antidepressant activity, antagonism of reserpine induced hypothermia and potentiation of yohimbine toxicity, the effect of clenbuterol was greater following chronic treatment.

[Fungal keratitis caused by Cylindrocarpon lichenicola]

We report a case of a 67-year-old woman with no significant past ocular history, who was referred for management of an unresponsive microbial keratitis resulting from trauma with a piece of clothing fabric 1 month previously in Portugal and worsening despite topical fortified antibiotics. On examination, visual acuity was limited to "light perception". Slit lamp examination revealed an 11×11mm full-thickness corneal infiltrate. Confocal images showed branching hyphae suggestive of a fungal infection. Fungal cultures of corneal scrapings revealed growth of Cylindrocarpon lichenicola, a saprophytic, filamentous fungus, which is an unusual cause of keratitis. Despite aggressive antifungal therapy with voriconazole and amphotericin B, she required penetrating keratoplasty for impending corneal perforation. Follow-up was uneventful, with no recurrence at 1 year. Fungal infections must be suspected in all corneal ulcers of traumatic etiology. Specific cultures and confocal microscopy must be performed early, so as to enable early treatment modification.

New anionic polyelectrolyte hydrogel for corneal surgery

A new high-water-content (78%) anionic polyelectrolyte hydrogel was obtained by phase inversion (demixion) of a polymer solution containing 9.0% poly(acrylonitrile sodium methallylsulphonate), 85.0% dimethylformamide, and 6.0% saline solution (0.9% NaCl). The hydrogel is permeable to water, saline, urea, creatinine, glucose, human albumin, and saline-dissolved oxygen. Investigation of the interactions between human serum and surfaces prepared with the new yielded hydrogel, compared to serum interaction with silica-free silicone (RTV), regenerated cellulose (Cuprophan), MMA/PVP copolymer (Lidofilcon), PMMA (Perspex), FIFE (Gore-Tex), and poly(acrylonitrile sodium methallylsulphonate) hemodialysis membrane (AN-69), showed the hydrogel and hemodialysis membrane (both prepared with AN-69 copolymer) to be the only materials devoid of complement (C')-activating ability.

Quality assessment of conjunctival specimens for detection of Chlamydia trachomatis by PCR in children with active trachoma

One component of control programmes to eliminate trachoma is the treatment of Chlamydia trachomatis infection. A diagnosis of trachoma is based on clinical grounds, but the signs of active trachoma do not always correlate with the presence of C. trachomatis. During a therapeutic trial, the level of C. trachomatis infection in children with active trachoma in Guinea and Pakistan was assessed using a qualitative commercially available PCR that targeted the C. trachomatis plasmid. The influence of the quality of specimens on the efficiency of the PCR was investigated using two quantitative real-time PCRs targeting the specific omp1 gene of C. trachomatis and human chromosomal DNA, respectively. C. trachomatis was detected in c. 23% of children (aged 1-10 years) who presented with clinically active trachoma. Controls showed that PCR-related problems did not influence this detection rate. For 14% of the positive samples, C. trachomatis was detected in only one eye, with a significantly lower mean load of bacteria. These results suggest that epidemiological and therapeutic surveys should be conducted by sampling and testing both eyes. Moreover, the high variability of the cell load observed in the conjunctival swabs suggests that the effectiveness of swabbing may be questionable.

Effects of non-steroidal antiallergic eyedrops on the complement-mediated histamine release from human cells

Leukocytes from ten allergic patients (five allergic to dust-mites and five allergic to pollen) were treated with N-acetyl aspartyl glutamic acid (NAAGA) 4.9%, disodium cromoglycate (DSCG) 2%, lodoxamide (LODO) 1%, and levocabastine (LEVO) 0.5% (concentrations representing the pharmaceutical eyedrop preparations) for 20 minutes. Degranulation was then induced with Complement (rHu5Ca). Histamine was measured in the supernatant with ELISA. LODO and LEVO were inactive in blocking histamine released from human cells, and paradoxical unexpected effects were found with these two agents. They both induced significant histamine release in almost 100% of the samples. DSCG was able to block histamine release in seven patients out of nine (ranging between 5 and 34%). NAAGA was the most active agent on human cells and was able to block basophil degranulation in nine patients out of nine (inhibition ranging between 4 and 66% of total histamine pool).

At the End of Every Pandemic: Beginning a Pandemic Playbook to Respond to the Next

The world was unprepared for COVID-19. Pandemics can unfold quickly; faster than governments can respond, unless they have maintained a realistic pandemic playbook. As the world ahead becomes ever-more complex, such playbook becomes ever-more necessary. This article not only describes the importance of a pandemic playbook but also a system to maintain it. A pandemic playbook both (1) specifies what is needed to respond to a pandemic and (2) provides a lens through which to identify measures that will keep people safe and society secure. The plays in the book are thought-though policies and strategies and corresponding implementation plans. The process of developing a playbook is as important as the product. Any playbook must be fit for purpose in the context of the times in which it is to be used. Above all, it must contain realistic policies and plans that can actually be implemented and can realize their intended effects. Achieving this goal requires (1) repeatedly exercising the playbook so that people know what to do when they need to do it and (2) evaluating results and updating the playbook to keep it relevant and current. Necessarily, to bring ideas alive, this article illustrates them with reference to COVID-19 and earlier pandemics, but it is not intended as a playbook for responding to the next pandemic; nor a postmortem on responses to COVID-19. Instead, it describes actions to take now to be ready when the next global pandemic strikes, so that policy decision-makers will not be lamenting “we should have done that.”