Malassezia dermatitis in dogs in Brazil: diagnosis, evaluation of clinical signs and molecular identification.

Skin carriage and quantification of Malassezia yeasts were evaluated in 180 healthy dogs (group 1) and 117 dogs with clinical signs (pruritus, erythema, lichenification/seborrhoea, excoriations and alopecia) that could be related to Malassezia dermatitis (group 2) in Brazil. The lesions in the group 2 dogs were evaluated using CADESI-03 scores. Samples were collected from five different anatomical areas. Direct examination was performed using the tape strip technique, and results were expressed as the mean number of yeasts per ×1000 microscopic field per dog. For mycological culture, a single piece of sterilized carpet was applied to the same areas sampled for cytology, and transferred onto Dixon's modified medium. Yeast populations were expressed as mean colony forming units (CFU)/plate. Malassezia isolates were characterized by polymerase chain reaction-restriction endonuclease analysis of the large subunit (LSU) of ribosomal RNA gene. The probability of culturing Malassezia from dogs with skin lesions was significantly higher (P<0.001) than from healthy dogs. There was a linear trend between CADESI-03 score and mean CFU/plate. Group 2 dogs with positive cultures had higher CADESI-03 scores than those with negative cultures (P<0.05). Almost all isolates were identified as Malassezia pachydermatis. Only one isolate (group 2) was identified as Malassezia furfur. These data suggest that dogs with skin disorders harbouring Malassezia yeasts in quantities higher than 120 mean CFU/plate should be considered as having Malassezia dermatitis. The presence of Malassezia appears to exacerbate clinical lesions in dogs.

Genetic variability and phospholipase production of Malassezia pachydermatis isolated from dogs with diverse grades of skin lesions.

Little detailed information is available on the association of Malassezia pachydermatis genotypes and the extent of skin damage that they cause. In the present study, isolates of M. pachydermatis, recovered from the skin of healthy dogs and dogs with dermatitis in Brazil, were characterized on the basis of partial sequencing of the large subunit (LSU), first internal transcribed spacer (ITS-1) and chitin synthase 2 gene (chs-2). The determination of phospholipase production was also included in the investigations. The severity of lesions and hyperpigmentation of dogs with skin disease were evaluated. For each locus, two main sequence types were designated as genotypes A and C. Two other minor sequence types (A2(I)-C2(I)) were also recorded and defined for the ITS-1. Genotype A isolates were the most prevalent, being recovered from healthy and diseased animals. No significant difference was detected among genotypes or ITS-1 sequence types and grades of skin damage or hyperpigmentation in the dogs with skin lesions. The number of M. pachydermatis isolates that produced phospholipase was statistically higher for diseased dogs than for strains found in healthy animals. The present study reveals that multiple genetic variants of M. pachydermatis occur in dogs and that the distribution patterns of particular genotypes on the skin of dogs in Brazil might be related to environmental and ecological factors which maintain distinctive genotype assemblages in specific geographical areas.

Impact of oral bases on aluminum absorption.

Control of hyperphosphatemia in renal failure is often difficult to achieve. Although calcium-containing phosphate binders have become the preferred phosphate binders, many patients require the addition of an aluminum-containing phosphate binder (APB). Enhanced aluminum absorption has been noted when APBs are administered with citrate-containing products such as citrate/citric acid solution (CCA). Alternative phosphate binders such as calcium acetate may also increase aluminum absorption. This study investigated the effect of CCAs on aluminum absorption when aluminum antacids (APBs) were administered concurrently and 2 hours apart. The effects of the alternative alkalinizing agent sodium bicarbonate and the alternate phosphate binding agent calcium acetate on aluminum absorption were also studied. During five 2-day phases, ten normal volunteers randomly received three times daily with standardized meals aluminum hydroxide alone and concurrently with NaHCO3, calcium acetate, CCA, or with CCA 2 hours postprandially. Twenty-four hour urines were collected on the second day of each phase and aluminum excretion was determined using inductively coupled plasma emission spectroscopy. Urine aluminum excretion was statistically significantly (P <.005) elevated in subjects receiving Al(OH)3 and CCA both with meals, 269.3 +/- 146.3 microg/d, and 2 hours after meals, 303.3 +/- 142.9 microg/d, compared with 79.2 +/- 52.0 microg/d during treatment with Al(OH)3 alone. Administration of CCA 2 hours after APB does not permit the safe use of these agents concurrently. Concomitant administration of sodium bicarbonate and calcium acetate with APBs appears to be safe, as aluminum absorption was not affected.

Epoprostenol in primary pulmonary hypertension.

OBJECTIVE: To review briefly the epidemiology, pathophysiology, and current treatment of primary pulmonary hypertension (PPH) and review the available clinical data on epoprostenol in PPH. DATA SOURCES: A MEDLINE search (January 1966-August 1998) was used to identify case reports and clinical studies pertaining to epoprostenol in PPH. Bibliographic lists were also used. STUDY SELECTION: All English-language clinical studies of epoprostenol in PPH were included. Incomplete study descriptions (abstracts) were not included. DATA EXTRACTION: Study design, population, methods, clinical outcomes, and adverse effects were evaluated. DATA SYNTHESIS: PPH is a relatively rare disease that results in symptoms of congestive heart failure and has a five-year survival rate of 34%. Therapy has consisted of vasodilators, anticoagulation, oxygen, and ultimately lung transplantation. Epoprostenol, which has recently become available as an integral pharmacotherapeutic option, has been shown to improve hemodynamic parameters such as cardiac output, pulmonary artery pressure, and pulmonary vascular resistance. It has been shown to improve exercise parameters, New York Heart Association (NYHA) functional class, and survival. Epoprostenol is indicated for patients with severe disease (NYHA class III or IV) who do not respond to acute vasodilator challenge or chronic calcium-channel blocker therapy. Its chronic administration is challenging as it requires continuous infusion via central venous catheter and a special infusion pump. Administration is further complicated by the 48-hour expiration of reconstituted epoprostenol and the need to refrigerate the reconstituted drug. CONCLUSIONS: Epoprostenol improves hemodynamics and clinical outcome in patients with severe PPH. Epoprostenol therapy requires intensive patient education and medical monitoring, but it can improve well-being and delay the need for lung transplantation.

Introduction to coronary artery stents and their pharmacotherapeutic management.

OBJECTIVE: To provide an introduction to coronary artery stents and their pharmacologic management, including anticoagulant therapy and newer antiplatelet regimens. DATA SOURCES: A MEDLINE and current journal search of relevant articles that evaluated coronary stent success rates and anticoagulation or antiplatelet regimens. STUDY SELECTION: Data from the use of primarily the Palmaz-Schatz stent were included. Studies using vitamin K antagonists that are not commercially available in the US were excluded unless they compared an antiplatelet regimen with anticoagulation using the international normalized ratio (INR). DATA SYNTHESIS: Limitations with percutaneous transluminal coronary angioplasty (PTCA), such as ischemic complications and restenosis, have led to the advent of intracoronary stenting. However, the placement of a stent within the coronary artery lumen is associated with a risk of thrombotic events. Despite current postprocedural anticoagulation and antiplatelet regimens, thrombosis occurs at rates ranging from 0.6% to 21%. When anticoagulation is deemed appropriate, it should be used for 1-2 months and the INR should be maintained between 2 and 3.5. Anticoagulation appears to have no effect on the development of restenosis, but has been shown to cause significant hemorrhagic events in 5-13.5% of patients. Newer data continue to define the subsets of patients who may be managed with antiplatelet agents alone. Combinations of aspirin and ticlopidine or aspirin alone may be used to manage patients who fulfill the following criteria: optimal stent placement, high-pressure inflation, and adequate coronary size. CONCLUSIONS: Coronary artery stenting is a novel approach for the management of coronary artery disease, but is associated with the complication of stent thrombosis. Anticoagulation reduces the risk of stent thrombosis, but is associated with bleeding risk. Selected patients may be successfully managed with antiplatelet agents only. More data are needed to better define the optimal antithrombotic regimen.

Comparison of tobramycin pharmacokinetics after administration by CRIS and a traditional intravenous piggyback infusion.

OBJECTIVE: To compare the administration pharmacokinetics of a 30-minute intravenous piggyback (ivpb) infusion of tobramycin with those of controlled-release infusion system (CRIS) using a 20-mL vial at rates of 60 and 120 mL/h. DESIGN: Randomized, controlled, crossover, prospective, open-label trial. SETTING: Medical college-affiliated hospital. PARTICIPANTS: Eight healthy volunteer men between the ages of 22 and 24 years weighing between 60 and 90 kg. INTERVENTIONS: Volunteers received, in random order, tobramycin sulfate 2 mg/kg i.v. on 3 occasions separated by 1 week. The drug was administered using a 50-mL ivpb infusion at 100 mL/h for 30 minutes, and with the CRIS using a 20-mL vial with flow rates of 60 mL/h for 1 hour (slow) and 120 mL/h for 1 hour (fast). MAIN OUTCOME MEASURES: Primary endpoints were area under the time-concentration curve (AUC), time to reach maximum concentration (tmax), and maximum concentration (Cmax). Secondary endpoints were elimination rate constant (ke), clearance (Cl), and half-life (t1/2). RESULTS: Six volunteers successfully completed the trial. The tmax values observed following fast CRIS and ivpb were 28 +/- 8 and 32 +/- 4 minutes, respectively, and not significantly different from each other. Both occurred significantly earlier than the tmax associated with slow CRIS (44 +/- 7 min). The Cmax values observed following ivpb (11.2 +/- 1.5 mg/L) and slow CRIS (10.9 +/- 0.9 mg/L) administration were not significantly different from each other, but both were significantly lower than that of fast CRIS (13.4 +/- 1.5 mg/L). The AUCs of slow and fast CRIS were 29.8 +/- 4.8 and 31.2 +/- 3.8 mg/L.h, respectively, and were not significantly different from each other. The AUC of fast CRIS was significantly greater than that observed with ivpb (27.4 +/- 4.3 mg/L.h). No significant difference in ke (fast CRIS 0.32 +/- 0.03 h-1; slow CRIS 0.33 +/- 0.04 h-1; ivpb 0.34 +/- 0.0 h-1) was observed among any of the methods. CONCLUSIONS: CRIS administration of tobramycin resulted in higher AUCs than did ivpb administration. Compared with ivpb, fast CRIS resulted in a higher Cmax, but the tmax values of fast CRIS and ivpb administration were not statistically different. Compared with ivpb, slow CRIS resulted in a more delayed tmax, but the Cmax values of slow CRIS and ivpb were not statistically different.

Beta-agonists in the treatment of acute exacerbation of chronic obstructive pulmonary disease.

OBJECTIVE: To critically evaluate the following issues regarding the use of beta-agonists in the treatment of acute exacerbations of chronic obstructive pulmonary disease (COPD): (1) optimal dose, (2) use of nebulizer (NEB) versus metered-dose inhaler-spacer devices (MDISs), (3) comparison with anticholinergic agents, and (4) use in mechanically ventilated patients. The patient populations addressed are limited primarily to emergency department (ED) and intensive care/acute care settings. DATA SOURCES: English-language journal articles published between 1977 and 1993. STUDY SELECTION: Nine studies were evaluated that included beta-agonists alone or in combination with other bronchodilators in the treatment of acute exacerbation of COPD. Many of the studies contained design flaws or were limited in size, making interpretation difficult. In studies containing both asthma and COPD patients, focus was restricted to analysis of COPD patients when possible. DATA EXTRACTION: Performed subjectively by the authors. Studies were evaluated for methodologic strengths and weaknesses. DATA SYNTHESIS: Dosing studies in patients with stable disease show a relationship between dose and the various pulmonary function tests (PFTs). Dose also correlates with duration of action and incidence of adverse effects. Four studies compared NEBs versus MDISs. Studies revealed significant improvement in PFTs for both treatments, with no significant difference between groups noted. Five studies compared various combinations of beta-agonists and ipratropium. Both ipratropium and beta-agonists caused statistically significant increases in PFTs from baseline. Combination therapy provided no further increase in spirometry compared with that of single-agent therapy. One study did report an early discharge from the ED with the addition of ipratropium. Most studies did not use large doses of beta-agonists or evaluate the effect of repeated doses. Many studies allowed concomitant therapy. Most did not include outcome measurements, such as ED length of stay, admission rates, hospital stay, or incidence of relapse. CONCLUSIONS: Dose-response studies in patients with stable disease suggest that doses of albuterol powder up to 1 mg may be tolerated safely, although use of repeated larger doses has not been well studied. Beta-agonists given by MDIS or NEB are equally effective in this setting. There is no apparent advantage to combined use of beta-agonist and ipratropium in the acute setting. Future research in this area should evaluate the use of larger or repeated doses of beta-agonists in the acute setting. Optimizing concurrent therapy and evaluating various patient outcomes should receive special attention in further investigations.

Dente ectópico em seio etmóide: caso clínico / Ectopic tooth in ethmoid sinus: a clinical case

Dentes ectópicos foram descritos em uma grande variedade de locais, sendo sua ocorrência em seios paranasais extremamente rara. Relatamos um caso no qual uma paciente com quadro clínico de sinuosi crônica foi submetida a tomografia computadorizada de seios da face que revelou a existência de uma pansinusite e uma estrutura de densidade óssea em regiäo de células etmoidais posteriores a esquerda. Esta paciente foi submetida a cirurgia tendo sido detectada durante o ato cirúrgico, uma estrutura de consistência óssea de aspecto morfológico semelhante a um dente. A descriçäo anatomopatológica da massa encontrada foi de dente ectópico de estrutura habitual. O diagnóstico clínico radiológico é muitas vezes inconclusivo, porém é importante, devido ao aumento de morbidade associada com tal patologia

Misadventures with activated charcoal and recommendations for safe use.

OBJECTIVE: To review published reports of adverse effects associated with single- and multiple-dose activated charcoal therapy, and to formulate recommendations for safe use of activated charcoal therapy. DATA SOURCES: A manual search of Index Medicus from 1970 to December 1993 was conducted for English language articles; bibliographies of the resultant articles were also scanned. STUDY SELECTION: Cases were included if they were described in full detail, resulted in significant morbidity or mortality, and uniquely contributed to the formulation of recommendations for safe use of activated charcoal therapy. DATA SYNTHESIS: The major causes of morbidity and mortality secondary to activated charcoal therapy are aspiration of charcoal, gastrointestinal obstruction, and fluid and electrolyte abnormalities. Aspirations have occurred as a result of a number of circumstances that may be avoided. These include use in patients with unprotected airways, use of excessive charcoal dose, administration of inappropriately diluted charcoal, and administration of charcoal in the field. Gastrointestinal obstruction has occurred when multiple doses of activated charcoal have been administered without a cathartic and in cases in which a cathartic was administered if the patient had impaired peristalsis. Fluid and electrolyte abnormalities have occurred secondary to excessive cathartic administration. CONCLUSIONS: Activated charcoal therapy should be used judiciously so that related morbidity and mortality can be prevented. Adequate consideration for the patient's airway protection capability is necessary. Judicious dosing of charcoal and concomitant cathartic therapy, along with adequate monitoring of fluid and electrolyte status, abdominal physical assessment, and clinical condition are all vital to the safe use of activated charcoal therapy.

Meperidine-related seizures associated with patient-controlled analgesia pumps.

OBJECTIVE: To report three cases of meperidine-related seizures when meperidine was administered via patient-controlled analgesia pump (PCAP) and to review literature related to meperidine-associated seizures. DATA SOURCES: Case reports and review articles identified by a computerized search (MEDLINE) and manual search (Index Medicus). DATA SYNTHESIS: PCAPs are being used frequently to relieve the pain of sickle cell crisis as well as pain from many other etiologies. We report three cases of meperidine-related seizures associated with its administration via PCAP. Each of the patients received either relatively high doses, long-term therapy, or both. Meperidine has been associated with seizure activity when administered via traditional routes. Previously identified risk factors for the development of meperidine-related seizures include renal failure, high meperidine dosages, and coadministration of hepatic enzyme-inducing medications or phenothiazines. CONCLUSIONS: Meperidine administered via PCAP may be associated with seizures. Optimally, an alternative analgesic should be administered when this route is used.

Comparison of pentoxifylline pharmacokinetics between smokers and nonsmokers.

Pentoxifylline is a synthetic xanthine derivative and is hepatically cleared. The natural dimethylxanthines theobromine and theophylline have been shown to have enhanced metabolism in smokers when compared with nonsmokers. Subsequently, the effect of smoking on pentoxifylline plasma concentrations was investigated. Twenty healthy volunteers (10 smokers and 10 nonsmokers) received pentoxifylline 400 mg as a controlled-release tablet every 8 hours for 17 doses. Several blood samples were collected for 8 hours after the final dose. These samples were assayed for pentoxifylline and its metabolites. The mean values of the smokers were compared with those of the nonsmokers. With respect to pentoxifylline, no statistically significant differences in maximum concentration and time of maximum concentration were observed between the two groups. Although no statistical differences in plasma concentrations and area-under-the-curve at steady state (AUCss) were observed, the oral clearance of pentoxifylline among the smokers (.22 +/- .08 L/minute/kg) was significantly greater (P < .05) than that among the nonsmokers (0.15 +/- 0.06 L/minute/kg) when corrected for body weight. With respect to the pentoxifylline metabolite 1-(5-hydroxy-hexyl)-3,7-dimethylxanthine (MI), the maximum concentration and AUCss of the smokers were significantly decreased when compared with the nonsmokers. The AUCss of the smokers was 1438 +/- 819 ng.hour/mL and of the nonsmokers was 2864 +/- 1375 ng.hour/mL (P < .02). The results of this trial suggest that smoking tends to reduce pentoxifylline plasma concentrations and significantly reduces MI plasma concentrations.

Comparative investigation of the influence of nizatidine, ranitidine, and cimetidine on the steady-state pharmacokinetics of theophylline in COPD patients.

The influence of usual regimens of the H2 blocking drugs, cimetidine, ranitidine, and nizatidine on the steady-state plasma concentrations and pharmacokinetic characteristics of theophylline was studied in seventeen patients with chronic obstructive pulmonary disease (COPD). Patients were dosed to steady-state with an oral, sustained-release formulation of theophylline given in therapeutic doses twice daily for 2 weeks. Over the next 4 weeks, each patient received a week-long regimen of each H2 blocker concomitantly with theophylline, and a week-long regimen of theophylline alone (control). At the end of each of the latter 4 weeks the steady-state pharmacokinetics of theophylline were assessed. Neither ranitidine nor nizatidine treatment altered the steady-state pharmacokinetics of theophylline relative to the control phase (i.e. no H2 blocker treatment). Values for theophylline C(ave), Cssmax, AUC0-12, and CLoral were significantly different during cimetidine treatment compared with all other treatments (ranitidine, nizatidine, and control). Cimetidine increased theophylline Cssmax, AUC0-12 and Cave by approximately 32%, and decreased theophylline oral clearance by approximately 23%. The authors conclude that cimetidine alters the steady-state pharmacokinetics of theophylline in COPD patients, whereas ranitidine and nizatidine are without effect.

Effect of serum separator tubes on free and total phenytoin and carbamazepine serum concentrations.

The effect of serum separator tubes (SSTs) on free and total serum phenytoin and carbamazepine concentrations was determined by comparing standard no-additive tubes with SSTs (Becton Dickinson SST and Terumo Autosep). The influence of time prior to centrifugation, sample volume, and initial drug concentration on the effects were also studied. Results were analyzed using repeated measures two-way analysis of variance with tube type and either time, sample volume, or concentration as main effects. The most significant reductions noted were with Becton Dickinson SSTs in free and total serum phenytoin and total carbamazepine concentrations, where all reductions were less than 10%. The only factor to significantly influence extent of reduction was the effect of time on total serum phenytoin concentration in Becton Dickinson SSTs. Terumo Autosep tubes caused no major reductions in free or total phenytoin or carbamazepine serum concentrations. Autosep tubes should provide accurate measurements of total and free serum phenytoin and carbamazepine concentrations. With Becton Dickinson SSTs, the reductions noted in free and total phenytoin and total carbamazepine concentrations were not large enough to preclude their clinical use. Becton Dickinson SSTs should not be used for determining free or total phenytoin or total carbamazepine concentrations for purposes of research.

Effect of aluminum hydroxide gel on quinidine gluconate absorption.

The effect of aluminum hydroxide gel on quinidine gluconate bioavailability was studied in eight nonsmoking healthy male volunteers. Subjects were randomized to receive quinidine gluconate 648 mg with and without 30 mL of aluminum hydroxide gel. The mean area under the concentration-time curve (AUC) (23.11 +/- 5.21 mg.h/L), time to reach maximum concentration (tmax) (3.13 +/- 0.64 h), maximum serum concentration (1.44 +/- 0.41 mg/L), and elimination rate constant (0.069 +/- 0.010-h) observed during the control phase of the trial did not differ significantly (p greater than 0.05) from values obtained during the coadministration of aluminum hydroxide with quinidine gluconate (23.91 +/- 4.48 mg.h/L, 4.13 +/- 2.12 h, 1.53 +/- 0.34 mg/L, and 0.077 +/- 0.013-h, respectively). There was considerable individual variation in AUC with one subject demonstrating an increase of 35 percent and one subject demonstrating a decrease of 18 percent. There was a trend toward aluminum hydroxide delaying tmax with only one subject experiencing an earlier tmax with the coadministration of aluminum hydroxide. The results of this single-dose trial suggest that, although statistically the concurrent administration of aluminum hydroxide gel with quinidine gluconate does not significantly alter the extent of quinidine absorption, clinically significant individual variations may occasionally occur.

Accuracy of two equations in determining normalized phenytoin concentrations.

The accuracy of two equations in normalizing total phenytoin concentrations in the presence of renal failure or hypoalbuminemia was evaluated in 11 renal failure and 23 hypoalbuminemic patients. Blood samples were obtained from hospitalized patients receiving phenytoin and were assayed for free and total phenytoin concentrations. Estimated normalized phenytoin concentrations based on free drug concentration were compared statistically with normalized concentrations calculated from the two equations via Student's t-test. The equation for normalizing phenytoin concentrations in hypoalbuminemic patients significantly underpredicted normalized phenytoin concentrations 15.7 +/- 8.5 versus 19.9 +/- 12.1 mg/L (p less than 0.001). In patients with renal failure, the mean phenytoin concentration from the respective equations and that based on free concentration were 14.1 +/- 6.2 and 14.0 +/- 7.9 mg/L, respectively. However, in 5 of 11 renal failure patients the equation resulted in over- or underprediction by at least 25 percent. Neither equation should be used clinically to normalize phenytoin concentrations in these patient populations.

Alteration of pentoxifylline pharmacokinetics by cimetidine.

Pentoxifylline, recently approved for the treatment of intermittent claudication, is hepatically cleared with a high degree of first-pass metabolism. Subsequently, the effect of cimetidine on pentoxifylline pharmacokinetics was studied in humans. Ten healthy subjects received, in random cross-over fashion, pentoxifylline 400 mg as a controlled-release tablet every 8 hours with and without cimetidine 300 mg four times a day for 7 days. Pentoxifylline and metabolite plasma concentrations over one dosing interval were measured on day 7 of each phase. The unavailability of an immediate-release pentoxifylline dosage form prevented a single dose trial. Cimetidine significantly increased (P less than .05) pentoxifylline area under the curve at steady state 26.2% from 675 +/- 97 (mean +/- SEM) to 852 +/- 108 ng. hr/mL. The average steady-state plasma concentration increased 27.4% from 84 +/- 12 to 107 +/- 14 ng/mL (P less than .05). Apparent oral clearance decreased 21.5% from 1309 +/- 304 to 1027 +/- 244 mL/min (P less than .02). Significant alterations in pentoxifylline metabolite concentrations were also observed. The results of this trial suggest cimetidine elevates pentoxifylline plasma concentrations, presumably by decreasing apparent oral clearance, although a reduction in total body clearance or an increase in gastric absorption could not be ruled out.