The Importance of Accurate Microorganism Identification in Microbial Challenge Tests of Membrane Filters. Part II. The Comparison of Hydrogenophaga pseudoflava ATTC 33668 and Curvibacter sp. ATCC 700892 by Microbial Challenge Tests with Membrane Filters.

The ASTM 838-05 standard describes a bacteria challenge test procedure based on Brevundimonas diminuta (ATCC 19146) to verify a 0.2 µm rated sterilizing-grade filter. For process validation procedures a correct identification of the challenge organism is essential. The test strain ATCC 700892 repeatedly used for microbial challenge tests was incorrectly named Hydrogenophaga pseudoflava but is phylogenetically linked to the genus Curvibacter, as shown in Part I of this series. Based on these studies the misconception was consolidated that Hydrogenophaga pseudoflava, a widely isolated microorganism also found in biopharmaceutical production settings, is able to penetrate 0.2 µm rated filters. Here we show that the bacteria challenge test results of the strains Curvibacter sp. ATCC 700892 and Hydrogenophaga pseudoflava ATCC 33668 are different. In previous challenge tests analytical filter membranes were used; these do not represent the process scenarios within the sterilizing filtration in industrial processes. To represent process systems, the study data presented were determined with 10" filter cartridge elements. The strain Hydrogenophaga pseudoflava ATCC 33668 is completely retained by 0.2 µm and 0.1 µm rated filters. Depending on the different 0.2 µm filter material there are different retention rates of the strain Curvibacter sp. ATCC 700892; only the 0.1 µm rated filters showed consistent complete retention. However, up to date the genus Curvibacter seems to be of low relevance within biopharmaceutical production settings. LAY ABSTRACT: Bacteria challenge tests are used to determine the retention performance of sterilizing-grade filters. The model organism used for bacteria challenge tests and the verification of a 0.2 µm rated sterilizing-grade filter is Brevundimonas diminuta. In previous studies another proposed, model organism used for challenge tests was incorrectly labelled as Hydrogenophaga pseudoflava. Given the predefined retention characteristics, this mislabelled organism was recommended to be included in bacteria challenge studies. However, the herein presented testing demonstrated that the organism is actually phylogenetically affiliated to the genus Curvibacter and not to the strain Hydrogenophaga pseudoflava ATCC 33668. In this report, we demonstrate that the retention of the strain Hydrogenophaga pseudoflava ATCC 33668 with 0.1 µm and 0.2 µm rated filters is comparable to the retention of Brevundimonas diminuta ATCC 19146.

The importance of accurate microorganism identification in microbial challenge tests of membrane filters--part I.

Microbial challenge testing is a common procedure to determine the retention efficiency, performance, and validity of a sterilizing-grade filter. The ASTM 838-05 standard describes a bacteria challenge test procedure based on Brevundimonas diminuta (ATCC 19146), routinely used to verify a 0.2 µm rated sterilizing-grade filter. Process validation procedures most often also utilize B. diminuta (ATCC 19146), but instead of the standard procedures and fluids, process, and product parameters are employed to determine whether these parameters influence the retentivity of the filter or changes to the challenge organism, which might result in the penetration of the filter. In certain instances, the native bioburden within the drug manufacturing process is used to perform such process validation challenge tests. Filter penetrations can happen and cause concern; therefore, it is essential to identify the organism species with accuracy to avoid unnecessary confusion. This paper and its follow-up will describe such imprecision and the resulting misconceptions. It will clarify past determinations and put perspective on the findings. LAY ABSTRACT: Sterilizing-grade filters are used to remove microorganisms from biopharmaceutical solutions. To determine the retention performance of such filters, bacteria challenge tests are utilized, often with a standard challenge organism (Brevundimonas diminuta), in instances with native bioburden. The accuracy of the microorganism identification is of importance to avoid flawed results and misinterpretation of the filter's performance.

Effect of arginine depletion on glomerular and tubular kidney function: studies in isolated perfused rat kidneys.

The effect of L-Arg depletion on glomerular hemodynamics and tubular function of isolated rat kidneys perfused with a medium containing 21 amino acids has been studied. A cyclooxygenase inhibitor was added throughout for blockade of prostaglandin synthesis. Arg depletion caused significant (approximately 30%) reductions in renal perfusion flow rate (PFR, 13.9 +/- 1.2 vs. 19.8 +/- 0.6 ml.min-1.g (kidney wt-1), glomerular filtration rate (GFR, 598 +/- 79 vs. 924 +/- 42 microliters.min-1.g kidney wt-1), and urine flow rate (139 +/- 38 vs. 192 +/- 13 microliters.min-1.g kidney wt-1) compared with control kidneys, which were perfused with a physiological concentration of Arg (200 microM). Filtration fraction (FF) increased with Arg depletion (5.1 +/- 0.4 vs. 4.4 +/- 0.4%). Arg-depleted kidneys had a lower absolute sodium (TNa, 75.7 +/- 8.8 vs. 107.9 +/- 6.0 mumol.min-1.g kidney wt-1) and glucose reabsorption (T glucose, 3.7 +/- 0.6 vs. 5.6 +/- 0.5 mumol.min-1.g kidney wt-1), corresponding to a lower sodium and glucose filtration. Potassium handling and reabsorption of free water were not changed. Oxygen consumption (QO2) was lower in Arg-depleted kidneys (4.6 +/- 0.3 vs. 5.5 +/- 0.5 mumol.min-1.g kidney wt-1). The effects of Arg depletion were completely reversed by the addition of Arg (1 mM) at 120 min and partly reversed by the addition of citrulline (1 mM). Ornithine depletion or addition had no effect on PFR, GFR, FF, TNa, T glucose, and QO2. N omega-methyl-L-arginine, a specific inhibitor of nitric oxide endothelium-derived relaxing factor, produced the same effect as Arg depletion.(ABSTRACT TRUNCATED AT 250 WORDS)

Subdiaphragmatic extralobar pulmonary sequestration.

A 21-day-old girl presented with a left subdiaphragmatic retroperitoneal mass discovered on maternal ultrasound at 23 weeks' gestation. The clinical impression was neuroblastoma, and preoperative workup showed no for metastatic disease. Histologically, the lesion proved to be an extralobar pulmonary sequestration. We present this case to remind pathologists of the occurrence of subdiaphragmatic pulmonary sequestration and its potential clinical confusion with other more familiar lesions that may occur in this location in a neonate.

The area of cancer in transurethral resection specimens as a prognostic indicator in carcinoma of the prostate: a computer-assisted morphometric study.

We used a computerized interactive morphometric method to determine total area of tissue and total area of cancer in routinely stained sections from each of 79 cases of prostatic adenocarcinoma, diagnosed by transurethral resection (TURP). The ability of two morphometrically determined parameters (area of cancer and percent area of cancer) to predict survival was compared with results obtained from two estimates of tumor area commonly used in clinical practice (number of chips and percent of chips involved by cancer). Total Gleason score was also determined. All patients were diagnosed prior to 1981, allowing follow-up of at least 5 years, or until death. Using the Cox proportional hazards regression analysis, our two morphometrically determined parameters, as well as the percentage of chips involved by cancer and total Gleason score, were significant predictors of survival. In contrast, the total number of chips involved by cancer did not reach statistical significance as a predictive factor for survival. By using our morphometrically determined area measurements as a bench mark for clinical utility of area estimates of cancer in TURP specimens, we concluded that calculating the percentage of involved chips yields prognostic information that closely approaches the "ideal" of these more time-consuming computer-assisted techniques.

[Assessment of the therapeutic effect of Trental 400. Double-blind study in geriatric patients with circulatory disorders]. / Zur Objektivierung der therapeutischen Wirksamkeit von Trental 400. Doppelblind-Versuch bei geriatrischen Patienten mit Durchblutungsstörungen

A double blind trial was performed in a geriatric unit in order to evaluate efficacy and tolerability of Trental 400 (400 mg Pentoxifylline per tablet) against a comparative formulation (2,4 mg adenosine per tablet) in 36 patients displaying signs of peripheral vascular disease and in 16 patients with symptoms of cerebrovascular disorders. 3 tablets were administered daily over a period of three months. Trental 400 proved to be significantly more effective in either indication group. Based on the observed good tolerability and pronounced efficacy Trental 400 can be considered as an easy to handle therapeutic tool for the long term treatment of symptoms resulting from peripheral and cerebral vascular disorders.