Partial purification and characterization of anhydrotetracycline oxygenase of Streptomyces aureofaciens

Anhydrotetracycline oxygenase was purified both by affinity chromatography and by hydrophobic interaction chromatography. Molecular weight of anhydrotetracycline oxygenase was determined to be 115,000 by Sephadex G-200 gel filtration. Using preparative isoelectric focusing the isoelectric point of the enzyme was estimated to be 5.3. The enzyme showed a sensitivity to thiol-specific inhibitors. During the hydrophobic interaction purification step, the activity dropped considerably. Reactivation occurred when a heat treated crude extract was added to the reaction mixture.     

Mixed epithelial and stromal tumors of the kidney. A report of 22 cases

Mixed epithelial and stromal tumor of the kidney (MESTK) is a recently described subset of renal neoplasm that tends to occur in middle-aged and older women and is characterized by a distinctive histological appearance. To further characterize this lesion, we report the clinicopathological and immunohistochemical features of 22 additional cases from our institutional files. Grossly, the tumors ranged in size from 1 cm to 14 cm (mean 6.7 cm), were well circumscribed but unencapsulated, and showed a cystic cut surface. The tumors were composed of a spindle cell proliferation that resembled ovarian stroma, as well as an epithelial component lining the cystic structures, which usually consisted of flat to hobnailed cells typical of collecting-duct epithelium. Areas displaying features of Müllerian differentiation were also documented in 6 cases, including epithelium of endometrioid, tubal, clear cell and squamous cell type as well as one case showing an architecture that closely resembled Müllerian adenofibroma and adenosarcoma. Follow-up in 14 patients (average 4.4 years) showed no evidence of recurrence or metastasis. We believe these tumors represent the renal counterpart of similar mixed epithelial and stromal neoplasms occurring in the biliary tract and pancreas, which is also characterized by cystic structures lined by epithelium, admixed with ovarian-type stroma. The differential diagnosis for these tumors includes cystic nephroma and cystic partially differentiated nephroblastoma, which we believe to represent clinically and morphologically distinct entities from MESTK. In particular, the distinction from cystic nephroma in adult male patients is emphasized, and two cases of this entity are included in the study for comparison.     

Economic impact and clinical benefits of pharmacist involvement on surgical wards

A one-year pilot project was performed to assess the economic and clinical benefit of pharmacist involvement on the surgical wards of a 600-bed tertiary care, teaching hospital. A total of 405 recommendations were collected with a physician acceptance rate of 90%. From these recommendations, 1416 patient follow-ups were performed to document outcome. The total documented cost avoidance of the pharmacists' activities was $33,265.58. The total annual drug expenditure for the department of surgery declined by $59,662 representing a 9% decrease over the previous year with the greatest decline involving antimicrobials which decreased by $52,587 compared with the previous year. Most of the cost-avoidance in this area was attributable to antimicrobial selection and dosing adjustment in renal impairment. Pharmacist-directed pharmacokinetic monitoring of aminoglycosides resulted in a clinical success rate of 93.8% for treatment regimens and a 6.2% incidence of nephrotoxicity. Housestaff education aimed at improving prescribing practices were identified and provided for select agents including midazolam, ketorolac, vancomycin and aminoglycosides. As well, select recommendations were documented which illustrated the benefit to patient care of pharmacist involvement. Pharmacist involvement on the surgery services produced both financial and clinical benefits.     

Evaluation of merbarone (NSC 336628) in disseminated malignant melanoma

Merbarone, NSC 336628, is an investigational anticancer drug with activity against experimental animal tumors including melanoma. This paper presents results of a Phase II clinical study of merbarone in patients with biopsy proven stage IV malignant melanoma without prior chemotherapy and with no evidence of CNS involvement. Thirty-five patients with median age 58 (range 27–81), with performance status 0–2 were treated with merbarone 1000 mg/m²/day for five days by intravenous continuous infusion repeated every 3 weeks. All patients (21 males and 14 females) were evaluable for toxicity. Two patients were not evaluable for response having been removed from protocol treatment due to toxicity and received other treatment during the first course of chemotherapy. Among the evaluable patients there was one complete response in a supraclavicular lymph node lasting four months and one partial liver response lasting three months. The remaining thirty-one patients were non-reponders. Of these one had a stable disease lasting 21 months. The overall objective response rate was 6% (2/35) with a 95% confidence interval of 1%–19%. Twenty-six of the 35 patients have died. The estimated median survival of the entire group was 9 months with a 95% confidence interval of six to eleven months. Renal toxicity was dose-limiting and manifested as increasing serum creatinine (54% of patients), proteinuria (51%) and hematuria (9%). One patient experienced grade 4 creatinine increase, proteinuria and acute renal failure. Other toxicities included nausea (71%), vomiting (51%), malaise (23%), weakness (20%), alopecia (17%), diarrhea (17%), anorexia (14%), transaminase (SGOT, SGPT) increase (14%), constipation (14%), alkaline phosphatase or 5nucleotidase increase (9%), and fever (9%). Hematologictoxicity (granulocytopenia, leukopenia, and anemia) was generally mild and infrequent (29%, only one patient had grade 4 granulocytopenia). Overall 9 patients (26%) had at least one grade 3 toxicity. We conclude that merbarone at this dose and schedule has detectable but minimal activity in the treatment of metastatic malignant melanoma and given the significant renal toxicity this schedule does not merit further evaluation in this disease.     

Altered Phosphorylation of Rat Dentine Phosphoproteins by Fluoride In Vivo

Dentine phosphoproteins have been proposed to have an important role in mineralization. This study focused on the influence of fluoride on the biochemical composition of dentine phosphoproteins and attempts to relate changes to the altered mineralization witnessed during fluorosis. Wistar rats were rendered fluorotic by the administration of 20 ppm sodium fluoride in their drinking water ad libitum, a nonfluorotic group received double-distilled, deionized water only. After 17 weeks, the teeth showed signs of fluorosis. The incisors were removed, split longitudinally, and the pulps were removed. Teeth were powdered and demineralized in 10% EDTA with protease inhibitors, after which the organic matrix was extracted with 4 M guanidinium chloride. Phosphoproteins were selectively precipitated from the soluble extract by the addition of 1.0 M calcium chloride and further purified by anion exchange chromatography. SDS-PAGE revealed two protein bands with molecular weights of 130 kDa and 66 kDa in the nonfluorotic fraction and 116 kDa and 66 kDa in the fluorotic fraction. Western blotting analysis identified the 66 kDa band as α₂-HS glycoprotein which co-precipitated with phosphoproteins. Electroelution of the protein bands was performed with subsequent biochemical analyses. Phosphate content was determined for each protein band and was detectable in the 116 kDa and 130 kDa bands from the fluorotic and nonfluorotic samples, respectively, with a decreased level noted in the 116 kDa band. The presence of phosphate and the amino acid analysis of these bands suggested their identity to be dentine phosphoproteins. No changes in the ratio of amino acids was detected in fluorotic samples. The fluoride-induced alterations to the biochemical structure of dentine phosphoproteins would appear to influence the phosphorylation of these macromolecules only, possibly affecting posttranslational events. Such alterations may play a role in disrupting the patterns of mineralization seen during fluorosis. Received: 14 November 1997 / Accepted: 9 July 1998     

Molecular Motion of Drugs in Hydrocolloids Measured by Electron Paramagnetic Resonance

The effects of a polymer, the Li-salt copolymer of methyl-methacrylic acid, and its methyl ester on the motion of drug molecules in hydrocolloids were studied. The investigation was carried out by means of electron paramagnetic resonance (EPR) using the model nitroxide tempol, and the spin-labeled drugs lidocaine (si-lid) and dexamethasone (sl-dex). Synthesis of sl-dex was performed. Spin-labeled molecules dissolved in hydrocolloids undergo a fast reorientation motion. The decreasing order of rotational correlation times () —sl-dex > si-lid > tempol—suggests that the size and the shape of the molecules strongly affect their motion. The inhibition of motion of larger molecules depends also on their flexibility. The values indicate proportionality of the microviscosity of hydrocolloids to the polymer concentration. Rotational motion is dependent on the local environment conditioned by the free spaces between polymer molecules.     

The Art of Building Decision Trees

Decision support systems that help physicians are becoming a very important part of medical decision making. They are based on different models and the best of them are providing an explanation together with an accurate, reliable, and quick response. One of the most viable among models are decision trees, already successfully used for many medical decision-making purposes. Although effective and reliable, the traditional decision tree construction approach still contains several deficiencies. Therefore we decided to develop and compare several decision support models using four different approaches. We took statistical analysis, a MtDeciT, in our laboratory developed tool for building decision trees with a classical method, the well-known C5.0 tool and a self-adapting evolutionary decision support model that uses evolutionary principles for the induction of decision trees. Several solutions were evolved for the classification of metabolic and respiratory acidosis (MRA). A comparison between developed models and obtained results has shown that our approach can be considered as a good choice for different kinds of real-world medical decision making.Art (from Latin ars meaning skill) is the skill in doing or performing that is attained by study, practice, or observation     

Properties of sustained-release single-dose formulations for vulvovaginal candidiasis

Vaginally applied imidazoles are the first-line treatment of vulvovaginal candidiasis (VVC). The need to develop a less messy and more patient acceptable treatment regimen led to the development of a treatment schedule from the original 3 weeks to 7 days and, then, to 3 days. Finally, it was attempted to design a single-dose treatment regimen. Currently in the US, three single-dose vaginal preparations are available: 2% butoconazole sustained release (SR) [100mg butoconazole; Gynazole-1®], 6.5% tioconazole (300mg tioconazole; Vagistat-1®), and 2% miconazole vaginal ovule (Monistat1®, combination pack providing an ovule of 1200mg of miconazole and 2% monistat cream for external use). Clotrimazole 500mg single-dose vaginal tablet was used earlier and has been withdrawn from the market. In clinical studies, treatment success is measured by the regression of signs and symptoms of VVC (clinical cure) and by the negative mycological cultures (microbiological cure). 2% butoconazole SR has been formulated in an emulsion that adheres to wet surfaces of vaginal mucosa infected with Candida albicans. After the single dose, butoconazole is gradually released from the emulsion in a sustained release fashion for 3–6 days and acts on the fungus. The results of treatment with 2% butoconazole SR were equivalent to a 7-day schedule with 2% miconazole. Adverse effects have been infrequent and usually mild. 2% butoconazole in the SR bioadhesive formulation is drug-sparing compared with treatment regimens providing a total of 300–700mg of imidazoles in 3–7 days. The second single-dose preparation, 6.5% tioconazole, for VVC provides tioconazole 300mg in a vaginal ointment. This compound has been compared with 2% miconazole in a separate and independent set of clinical trials; 2% miconazole was superior to 6.5% tioconazole in the microbiological cure rates at the first follow-up examination. The success of a single-dose antifungal treatment also depends upon the vehicle used to deliver the active drug to the target tissue. In case of 2% butoconazole SR the vehicle is formulated as a hydrophilic emulsion that adheres to the surface of the moist vaginal mucosa for 3–6 days. Representative of the orally active preparations is a single dose of fluconazole 150mg. The efficacy results of oral fluconazole are similar to the 7-day vaginal antifungal preparations; however, there is the possibility of the development of resistance and systemic adverse effects affecting the liver and kidneys. The sustained-release technology used for single dose of 2% butoconazole is an innovative approach to vaginal drug delivery.     

The use of absorbable polyglactin/polydioxanon implant (Ethisorb) in non-surgical closure of oro-antral communication

Oro-antral communications (OAC) greater than 4-5mm in diameter can seldom be counted on to heal spontaneously without the necessity for surgical closure. The initial experience in applying an absorbable polyglactin/polydioxanon implant (Ethisorb^®), in non-surgical closure of OAC ranging from 5 to 7 mm in diameter, is presented. Twelve patients of varying ages with OAC up to72 h in duration, have been treated with Ethisorb^®. Failures were not demonstrated in the form of the creation of an oro-antral fistula (OAF), and in all patients, OAC-s were closed with the epithelization of post-extraction wounds up to 21 days after implantation of Ethisorb^®. Based on these initial encouraging results, we propose that an Ethisorb^® biopolymeric absorbable implant can be used in selected clinical cases for non-surgical closure of OAC.