Treatment of severe, chronic hand eczema: results from a UK-wide survey.

Treatment of severe hand eczema (HE) that is resistant to topical potent corticosteroid treatment is challenging. In 2013, we surveyed 194 UK dermatologists to obtain information about their usual treatment pathways to inform the choice of the comparator in a trial of alitretinoin in severe HE (ALPHA trial); the results indicated that the treatment approaches favoured by UK dermatologists differ. Psoralen combined with ultraviolet A (PUVA) and alitretinoin were identified as the most frequent first-line treatment options for hyperkeratotic HE, whereas oral corticosteroids were identified as the most frequent first-line treatment for vesicular HE, followed by PUVA and alitretinoin. In terms of potential adverse effects of long-term or repeated use, oral steroids and ciclosporin A were reported to cause most concern. There is uncertainty about which treatment gives the best short and long-term outcomes, because of a lack of definitive randomised controlled trials evaluating the effectiveness of different treatment pathways in severe HE.

Emerging tropical diseases in Australia. Part 3. Australian bat lyssavirus.

Since its discovery in a juvenile black flying fox (Pteropus alecto) in 1996, Australian bat lyssavirus (ABLV) has become the cause of a potentially important emerging disease for health authorities in Australia, with two human deaths (one in 1996 and one in 1998) attributed to the virus in the north-eastern state of Queensland. In Australia, the virus has been isolated from all four species of flying fox found on the mainland (i.e. P. alecto, P. scapulatus, P. poliocephalus and P. conspicillatus) as well as a single species of insectivorous bat (Saccolaimus flaviventris). Australian bat lyssavirus belongs to the Lyssavirus genus and is closely related, genetically, to the type strain of Rabies virus (RABV). Clinically, patients infected with ABLV have displayed the 'classical' symptoms of rabies and a similar disease course. This similarity has led to the belief that the infection and dissemination of ABLV in the body follows the same pathways as those followed by RABV. Following the two ABLV-related deaths in Queensland, protocols based on the World Health Organization's guidelines for RABV prophylaxis were implemented and, presumably in consequence, no human infection with ABLV has been recorded since 1998. ABLV will, however, probably always have an important part to play in the health of Australians as the density of the human population in Australia and, consequently, the level of interaction between humans and flying foxes increase.

Mutations in human cytomegalovirus UL97 gene confer clinical resistance to ganciclovir and can be detected directly in patient plasma.

Specific mutations in the UL97 region of human cytomegalovirus (HCMV) have been found to confer resistance to laboratory-adapted strains subjected to ganciclovir selection. In this study, mutations in the UL97 region of HCMV isolates obtained from patients receiving ganciclovir therapy were examined to determine whether they would confer ganciclovir resistance, and if these mutations could be detected directly in the plasma of AIDS patients with progressive HCMV disease despite ganciclovir treatment. A single nucleotide change within a conserved region of UL97 was found in five resistant isolates, resulting in an amino acid substitution in residue 595: from leucine to phenylalanine in one, and from leucine to serine in four resistant isolates. A sixth resistant isolate demonstrated a single nucleotide change, leading to a threonine to isoleucine substitution in residue 659. The role of the 595 amino acid substitution in conferring ganciclovir resistance was confirmed by marker transfer experiments. In further studies, direct sequencing of HCMV DNA present in plasma obtained from persons with resistant viruses revealed the identical amino acid substitutions in plasma as those present in the cultured viruses. These findings indicate that clinical resistance to ganciclovir can result from specific point mutations in the UL97 gene, and that the emergence of the resistant genotype can be detected directly in patient plasma.

Effect of protein binding on cefmenoxime steady-state kinetics in critical patients.

The effect of protein binding on cefmenoxime steady-state kinetics was studied in 20 critical patients with gram-negative pneumonia. Sixteen patients were given 1 gm cefmenoxime every 6 hr, two received 2 gm every 6 hr, and two received 2 gm every 8 hr. Serum protein binding was measured by equilibrium dialysis. Assays were by HPLC. Serum cefmenoxime concentration-time data were characterized by a model-independent method based on statistical moment theory. Despite varying renal function in patients, mean cefmenoxime serum concentration-time curves for all three dosing regimens were closely aligned, reflecting successful empiric dosage adjustment. Terminal phase t 1/2 ranged from 0.8 to 2.9 hr and was significantly related to creatinine clearance. Cefmenoxime total clearance was significantly related to both lambda z (2.303 times the slope of the terminal portion of the log-concentration-time curve) and creatinine clearance (CCr). Plasma clearance of free cefmenoxime was more strongly correlated with CCr than the clearance of total cefmenoxime. Drug recovery from 24-hr urine collections at steady state was 76.9 +/- 19.8% of the daily dose (mean +/- SD, n = 13). Cefmenoxime protein binding in patients differed markedly from normal values. A regression equation derived from data on 11 cephalosporins appeared to predict total volume of distribution in the steady state (Vdss-Total) from the fraction of unbound drug accurately. Since cefmenoxime has a high therapeutic index, no clinical consequences are expected to result from variation in protein binding. Observed differences in protein binding between patients and normal subjects could have clinical consequences for highly bound acidic drugs that, unlike cefmenoxime, have narrow therapeutic indices.

Ranitidine disposition and systemic availability in hepatic cirrhosis.

Single-dose ranitidine kinetics were studied in 10 patients with cirrhosis as proved by liver biopsy. All were clinically stable. After an overnight fast, ranitidine was given in a randomized crossover order as a bolus intravenous injection (50 mg) or was taken by mouth (150 mg). Terminal t1/2 was 2.7 +/- 0.4 hr after oral dosing and 2.9 +/- 0.4 hr after intravenous injection. Total plasma clearance was 470 +/- 170 ml/min and the steady-state volume of distribution was 1.2 +/- 0.2 l/kg. There was considerable intersubject variability in the ranitidine serum concentration-time profile after oral dosing. Systemic availability as assessed by AUC analysis was 58% +/- 11%. Not all of the dose could be recovered in the urine as unchanged ranitidine and its known metabolites after intravenous injection. At 0.5 microgram/ml the serum protein binding of ranitidine was 4.6% +/- 1.3%. It is concluded that disposition of ranitidine in these 10 stable subjects with cirrhosis was not significantly altered. The minor changes observed in some were as likely to be the result of secondary perturbations in physiologic status as to effects of cirrhosis on drug metabolism.

Cimetidine kinetics during resuscitation from burn shock.

Severely burned patients suffer from rapidly changing metabolic and hemodynamic abnormalities that could alter drug kinetics. The kinetics of cimetidine, commonly used in the prophylaxis of acute stress erosions, were studied during fluid resuscitation of 11 patients with mean burn sizes of 45% total body surface area. Six patients were studied after the completion of fluid resuscitation. Total clearance, steady-state volume of distribution, and cimetidine t1/2 did not change between the early period after burn and after fluid resuscitation, but before the completion of fluid resuscitation patients had lower renal and greater nonrenal cimetidine clearance than after resuscitation. The increase in nonrenal cimetidine clearance resulted in decreased urinary recovery of unchanged drug, 50.7 +/- 14% during fluid resuscitation and 81.0% +/- 6% after resuscitation.

Role for dual individualization with cefmenoxime.

Cefmenoxime concentration/effect relationships were retrospectively explored for gram-negative bacteria isolated from 14 critical care patients treated for nosocomial pneumonia. The effects of cefmenoxime concentrations on in vitro growth kinetics of 21 isolated pathogens were studied using the Abbott MS-2 Research System, from which a dynamic response concentration was derived. Serum pharmacokinetic profiles were obtained in each patient. These data were used to calculate the in vivo total area under the curve over dynamic response concentration and the time that cefmenoxime concentrations exceeded the dynamic response concentration for each bacteria. The same determinations were made in 18 patients prospectively treated, except that dosage was optimized on the basis of previous mathematical relations to achieve bacterial eradication in four days. This method of dosage optimization is termed dual individualization. Serial cultures of infected tissues were evaluated to determine the number of days to the eradication of bacteria, and the pharmacokinetic and pharmacodynamic variables were used to describe the bacteriologic response of the original pathogen isolated in pretreatment culture. Bacterial eradication rates could be described from cefmenoxime pharmacokinetics in the patient and from the relation between concentration and bacterial inhibition. Patients who were prospectively treated using these retrospectively derived relationships had a predictable day of bacterial eradication. This, in turn, was associated with a shorter duration of treatment (p less than 0.05). The success of prospective dual individualization is encouraging and suggests that more precise optimization of antibiotic dosage can yield a predictable rate of bacterial eradication from the infection site.

Treatment with aztreonam or tobramycin in critical care patients with nosocomial gram-negative pneumonia.

During the course of one year, 47 critical care patients with gram-negative bacillary pneumonia at Millard Fillmore Hospital were randomly assigned to aztreonam or tobramycin therapy (two to one). Of these, 40 were fully evaluable for microbiologic and clinical response. All evaluable patients had gram-negative organisms in tracheal aspirate culture specimens and confirmed susceptibility of the organism to both study drugs. There was no difference between the two groups with respect to the percentage of patients who received concurrent antibiotics for gram-positive organisms. More than 60 percent of the patients received mechanical ventilation. Essentially, all had new lung infiltrates as shown by chest radiography, leukocytosis, recent onset of fever, and increased volume of purulent secretions. Half had multilobar pulmonary infiltrates. Their mean age was 73 years, with none under age 50. Most had chronic obstructive pulmonary disease, congestive heart failure, or both. By the prognostic nutritional index criteria, over 70 percent were nutritionally deficient at entry. The majority of infections were caused by Pseudomonas, Enterobacter, Klebsiella, and Escherichia coli. Aztreonam eradicated 92 percent of the causative gram-negative organisms, compared with 57 percent for tobramycin (p less than 0.05). Aztreonam produced a favorable clinical response (cure or improvement) in 93 percent of patients, compared with 50 percent for tobramycin (p less than 0.05). There were no differences in the minor adverse effects observed in the two treatment groups. Overall, aztreonam was superior to tobramycin for treatment of pneumonia due to susceptible gram-negative bacteria in these critical care patients.

Prostanoids in platelet-vascular interactions.

Prostacyclin, the labile prostanoid product of arachidonic acid metabolism in vascular endothelium, is the most potent known inhibitor of platelet aggregation and is highly effective in relaxing vascular smooth muscle. Its production is probably critically important in the maintenance of an intact vasculature. Although there is some evidence that prostacyclin circulates as a hormone, it is probably most important as a locally active agent in preventing thrombosis and maintaining patent vessels. Several factors can influence prostacyclin production, the most important of which probably act locally at sites of vessel wall injury. The most promising therapeutic approaches toward using prostacyclin's beneficial effects in vascular disease may lie in the use of drugs aimed at increasing prostacyclin production. Among these are thromboxane synthesis inhibitors, which act by diverting prostaglandin endoperoxides through the prostacyclin synthetase pathway, and lipoxygenase inhibitors, which might act chiefly by preventing formation of metabolites capable of inhibiting prostacyclin synthetase.

Clinical failure of CMV retinitis with intravitreal cidofovir is associated with antiviral resistance.

OBJECTIVES: To determine the incidence of clinical resistance to intraocular cidofovir injection for treatment of acquired immunodeficiency syndrome (AIDS)-related cytomegalovirus (CMV) retinitis, and to identify virologic features associated with cidofovir treatment failure. PATIENTS AND METHODS: Clinical resistance to intravitreal cidofovir was examined in 64 patients with CMV retinitis who received at least 1 injection of 20 pg of cidofovir. Histopathologic examination, culture, and polymerase chain reaction were used to detect CMV in ocular specimens. Antiviral resistance was assessed by plaque reduction assay and DNA sequencing. RESULTS: Clinical resistance to intravitreal cidofovir injections was identified in 3 patients (5%) and was associated with prior oral ganciclovir or intravenous cidofovir use. Ganciclovir- and cidofovir-resistant CMV isolates were cultured from 2 patients and harbored resistance-associated mutations in the UL97 and polymerase genes. Resistance mutations were also detected by direct analysis of vitreous. In 1 patient, different resistance mutations were identified in ocular vs extraocular CMV strains. CONCLUSIONS: Clinical failure of intravitreal cidofovir occurs infrequently, but may be associated with cidofovir-resistant CMV selected by prior ganciclovir or cidofovir treatment. Ocular CMV disease can result from a localized infection with a resistant CMV strain, and antiviral resistance may develop at a local site of infection independently from resistance that develops systemically.

Pharmacokinetics and pharmacodynamics of tepoxalin after single oral dose administration to healthy volunteers.

This study was conducted to examine the pharmacokinetics and pharmacodynamics of tepoxalin in healthy volunteers, an antiinflammatory compound that inhibits cyclooxygenase and lipoxygenase. Tepoxalin was absorbed after oral administration of single doses from 35 to 300 mg, after which it was rapidly converted to an acidic metabolite, RWJ 20142, which inhibits cyclooxygenase but not lipoxygenase. The areas under the concentration-time curve (AUC) of tepoxalin and RWJ 20142 in plasma increased in a dose-dependent fashion. Administration of the lowest dose of tepoxalin completely inhibited whole blood cyclooxygenase for the entire period of observation. This inhibition correlated closely with that of secretion and aggregation induced by collagen of platelets obtained from these subjects. Similarly, administration of tepoxalin was associated with significant inhibition of lipoxygenase in whole blood. Lipoxygenase was inhibited a maximum of 60% in a time-dependent fashion, and the duration of inhibition was dose-dependent. These studies demonstrate that tepoxalin inhibits whole blood cyclooxygenase, lipoxygenase, and platelet function after oral administration in humans.

The effects of very low fat diets enriched with fish or kangaroo meat on cold-induced vasoconstriction and platelet function.

Eighteen healthy volunteers consumed very low fat diets (less than 7% of daily energy) enriched with different sources of long chain (C20 and C22) polyunsaturated fatty acids (PUFA). Three diets provided 500 g/day of fish caught in the tropical waters of Australia (rich in arachidonic acid and docosahexaenoic acid), fish caught in the southern waters of Australia (rich in docosahexaenoic acid), or kangaroo meat (rich in linoleic and arachidonic acids). The fourth diet was vegetarian, similarly low in fat but containing no 20- and 22-carbon PUFA. An increase in the percentage of a particular C20 or C22 PUFA in the plasma phospholipid fraction in subjects consuming these low fat diets corresponded to the dietary PUFA composition. This study examined the effect of dietary modification of the level of arachidonic acid in plasma phospholipids on both traditional measures of platelet function and on cold-induced vasoconstriction. The cold pressor response, measured by venous occlusion plethysmography, was depressed in diets which elevated the levels of arachidonic acid in plasma lipids (kangaroo and tropical fish), enhanced after subjects consumed a diet which increased the levels of docosahexaenoic acid and eicosapentaenoic acid (southern fish diet), and was unchanged by the low fat vegetarian diet. There was no effect on bleeding time or platelet responsiveness.

Development of a fluorogenic RT-PCR assay (TaqMan) for the detection of Hendra virus.

A rapid and sensitive one-tube RT-PCR assay using a fluorogenic (TaqMan) probe was developed to improve the diagnosis of Hendra virus (HeV) infection. The TaqMan assay was developed to rapidly and specifically identify Hendra virus. The sensitivity of the new TaqMan-based PCR assay compared favourably with conventional RT-PCR. The major advantage of the TaqMan-based assay was the speed of diagnosis with results available within minutes of completing the PCR, and within 4 h of receiving the specimen. This test greatly reduces the chance of false positives through the elimination of second-round PCR and the requirement for agarose gel. Recombinant primer controls consisting of the Hendra virus primer sequence flanking a rodent GADPH probe sequence and recombinant probe controls consisting of the rodent GADPH primer sequence flanking the Hendra virus probe sequence were designed, cloned and transcribed in vitro to generate RNA. This has alleviated the requirement for viral RNA to be used as positive controls, thus reducing the chance of producing a false positive, at the same time eliminating the biosafety risk associated with handling live virus. This assay will provide a rapid diagnosis of future outbreaks of Hendra virus.

Lack of effect of gliclazide on platelet aggregation in insulin-treated and non-insulin-treated diabetes: a two-year controlled study.

Previous studies have suggested that the sulphonylurea hypoglycaemic agent gliclazide has specific effects in inhibiting platelet aggregation, and other haemorrheological effects that could be beneficial in preventing diabetic microangiopathy. A double-blind trial of the effect of gliclazide on platelet aggregatory responses was performed in 51 diabetic patients. Insulin- and non-insulin-treated diabetics were assessed during an initial 12-month placebo period, and in a subsequent 24-month active period after randomisation into placebo and gliclazide groups in insulin-treated patients or to glibenclamide and gliclazide groups in non-insulin-treated patients. Platelet-rich plasma was obtained from patients at intervals of at least 6 months during the trial. Circulating platelet aggregates were estimated, platelet aggregation was studied in response to three concentrations of adrenaline, ADP and collagen and thromboxane B2 produced by platelets exposed to collagen was measured. No significant effect of gliclazide was demonstrated on any parameter of platelet function evaluated.

The effect of platelets on the in vitro response to prothrombin complex concentrates in F.VIII inhibitor plasma.

Incubation of prothrombin complex concentrates, both non-activated and activated, in plasma enhances coagulation. The effect is reduced with time and is augmented when platelets are present. Such concentrates correct the coagulation abnormality in vitro in haemophilic plasmas with factor VIII inhibitors and the correction is greater in platelet rich than platelet poor plasma. Platelets appear to protect incubated concentrates from inhibitors present in plasma. Platelets may play a role in mediating the in vivo clot-promoting activity of some components of these concentrates. This effect may contribute to unwanted thrombosis or, conversely, may facilitate the sometimes-observed haemostatic effect of concentrates in patients with inhibitors of factor VIII.

Hyperviscosity syndrome in disseminated breast adenocarcinoma.

Circulation within the bloodstream of mucin derived from mucin-producing adenocarcinomas has been documented infrequently but has been associated with vascular occlusion, organ infarction, and hyperviscosity. The nature of the mucin and the therapeutic role of plasmapheresis in this condition has not been reported. A 64-yr-old female, who had undergone a mastectomy 3 yrs previously for an infiltrating mucinous breast adenocarcinoma, presented with dementia. A blood film showed marked rouleaux and a bluish background. No abnormal bands were detected on plasma protein electrophoresis. Blood, serum and plasma viscosity were above the range of readability of the viscometer. A bone marrow biopsy showed replacement with tumor similar to the original. Repeated plasmaphereses substantially reduced viscosity and temporarily improved her mental state. Post mortem revealed numerous infarcts with eosinophilic mucoid material in the lumen of many small vessels. That the offending plasma constituent was a sialomucin was suggested by mucin stains of the tumor and peripheral blood, a plasma sialic acid level 10 x normal and a substantial fall in viscosity after in vitro treatment of plasma with neuraminidase.

Inhibition of PAF-induced activation of human platelets by verapamil.

Verapamil, an inhibitor of calcium channels, was shown to inhibit PAF-induced platelet activation. In the presence of 50 microM Verapamil both thromboxane (Tx) formation and release of ATP from dense granules induced by 100 nM PAF was completely inhibited. This concentration of Verapamil only produced partial inhibition of PAF-induced aggregation. It also reduced the size of the PAF-induced calcium (Ca2+) transient demonstrated in Fura-2 loaded platelets. In the absence of extracellular Ca2+, following chelation by EGTA, PAF was still able to induce a Ca2+ transient confirming the requirement of both intra and extracellular Ca2+ for PAF-induced platelet activation. 100 microM Verapamil was able to completely abolish the calcium transient induced by low doses of PAF. These results further suggest that Verapamil is able to inhibit PAF-induced platelet activation by mechanisms apart from blocking Ca2+ channels.

Pharmacokinetics and bioavailability of bemoradan, a long-acting inodilator in healthy males.

Bemoradan is a potent, long-acting orally active inodilator. The pharmacokinetics and bioavailability of bemoradan were studied in twelve normal males following oral administration of single, ascending doses of the bemoradan HCL salt in capsules. Plasma and urine levels of bemoradan were determined by HPLC (detection limits: approximately 0.5 ng/ml for plasma and 5 ng/ml for urine). Bemoradan was rapidly absorbed from the capsule formulation at all doses (Cmax occurred at 2.1-2.4 hours). Bemoradan was slowly eliminated from the body (harmonic mean t1/2 16-23 hours). There was a dose-proportional increase in the AUC (0-48) values of bemoradan in humans following the administration of 0.5, 1, 1.5 and 2 mg of bemoradan. The AUC (0-48) values increased to 2.3, 3.4 and 4.0 times when the dose was increased to 2, 3 and 4 times. Urinary excretion of unchanged bemoradan accounted for approximately 5-12% of the dose. Results from this study and previous studies in rats and dogs indicate that bemoradan is well and rapidly absorbed after oral dosing, has linear pharmacokinetics and long elimination half-lives across species.

Evaluation of hemoglobin A2 quantitation assay and hemoglobin variant screening by capillary electrophoresis.

To critically assess the method of capillary electrophoresis, we examined 97 clinical samples submitted for hemoglobin electrophoresis by both conventional methods (electrophoresis on cellulose acetate and citrate agar for detection of abnormal variants, ion-exchange chromatography for quantification of HbA2, alkali denaturation for quantification of HbF, supravital stains for detection of HbH) and CE. CE was performed using a 72 cm (50 cm to detector) x 50 microns i.d. fused-silica capillary with detection of absorbance at 200 nm. Of the 97 samples examined, 34 contained a hemoglobin variant. Migration time, the difference of the variant peak to that of HbA, was used in an attempt to identify the hemoglobin variant by CE. We found the method to be suitable for the quantification of HbA2, useful as a screening technique for the presence of hemoglobin variants, but unsuitable for the quantification of HbF.