Failure of polymyxin B nonapeptide to augment bactericidal activities of novobiocin, rifampin, and of defibrinated human blood against Serratia marcescens

Polymyxin B (PB) and polymyxin B nonapeptide (PBNP), when combined with rifampin or novobiocin, but not vancomycin, yielded additive inhibitory effects against test strains of Serratia marcescens of three varieties: those that produced cocarde growths around PB disks (coc+); those that grew adjacent to PB disks (coc-, 6); and those that yielded clear inhibition zones around PB disks (coc-, clear). However, time kill curve experiments disclosed that only the combination of rifampin + PB exerted a potent bactericidal effect against coc+ strains of S. marcescens; rifampin + PBNP and novobiocin + PB or PBNP merely effected transient decreases of colony counts. Assays involving 50% (v/v) of fresh defibrinated human blood + PB or PBNP revealed that only PB clearly augmented the antibacterial activity of blood against coc+, and less so against coc- test strains of S. marcescens.     

Cotrel-Dubousset (CD) instrumentation for the correction of spinal curvature. First results in special consideration of derotation

At the University of Innsbruck, Department of Orthopedics, 30 scoliosis patients were operated on using the surgical method according to Cotrel-Dubousset in the period of May 1986-December 1987. For the correction of the curvature this instrumentation uses both distractive as well as transverse forces and attains such an unusual primary stability that postoperative immobilization by brace becomes unnecessary. In addition, it permits the three-dimensional correction of scoliosis curvatures. With an average preoperative measurement of 65.4 degrees and a postoperatively measured angle of 23.8 degrees the correction achieved is 64%. Rotation of the scoliosis was reduced by 39%. Our experiences with the application of the described method of operation and the pertinent complications are described below.     

Intravenous cholangiography,ERCP, and selective operative cholangiography in the performance of laparoscopic cholecystectomy

Between March 1990 and March 1993 some 822 consecutive patients underwent an attempt at laparoscopic cholecystectomy. Intravenous cholangiography (IVC), ERCP, and selective intraoperative cholangiography (IOC) were used in the evaluation of common bile duct (CBD) stones. Two hundred thirteen patients (26%) were identified preoperatively with either abnormal liver functions or a dilated common bile duct suggestive of CBD stones. IVC was performed in 143 patients (67%). Choledocholithiasis was identified in 14 patients (10%). Preoperative therapeutic ERCP was successful in all 14 patients (100%). Diagnostic ERCP was attempted in 61 patients and successful in 59 (97%). Choledocholithiasis was identified in 25 patients (41%). Successful extraction was accomplished in 23 patients (92%). Transcystic common bile duct exploration was used effectively in the patients with an unsuccessful ERCP. IOC was attempted in 50 patients and successful in 48 (96%). Choledocholithiasis was identified in three (6%). A retained CBD stone was present in eight patients (1%). There was one level I CBD injury (0.122%). The use of IVC, selective ERCP, and selective IOC is a reasonable approach in the performance of laparoscopic cholecystectomy.     

Analysis of mast cell subpopulations (MCT, MCTC) in cutaneous inflammation using novel enzyme-histochemical staining techniques

Abstract In order to gain insights into the dynamics of mast cell subpopulations in normal and diseased skin, a novel enzyme-histochemical double and triple staining method was employed that allowed the detection of metachromasia (toluidine blue) and the mast cell proteases tryp-tase and chymase within the same cell. Cryostat sections were used of skin biopsies from the following specimens: normal skin (N=4), psoriasis (N=13), atopic eczema (N=7), lichen planus (N=6), interferon α2a injection sites (N=l) of a leukemic infiltrate and corresponding normal skin of the same patient before and after treatment. (i) Equal numbers of tryptase-and chymase-positive mast cells (MCTC) were obtained in all normal and diseased specimens in papillary and reticular dermis, with threefold increases around appendages, (ii) Tryptase-positive mast cells (MCT) were absent in normal skin, but were markedly increased in a disease-specific pattern within the papillary dermis, the inflammatory infiltrate and around appendages, (iii) Marked increases of MCT were also noted at interferon injection sites within the leukemic infiltrate, but not in the normal skin of the same patient. These data suggest that disease-dependent mast cell dynamics involve only MCT in cutaneous inflammation and that MCT numbers are controlled by distinct, disease-specific local tissue factors.     

Gemfibrozil reduces plasma prothrombin fragment F1 + 2 concentration, a marker of coagulability, in patients with coronary heart disease.

The effects of gemfibrozil on several indices of haemostatic activity were explored in male patients with coronary heart disease (CHD). Sixty-three of 71 patients completed a crossover study in which gemfibrozil 1,200 mg/day and matching placebo were each taken in randomised order for 2 months in a double-blind manner, separated by a 2-month washout period. Serum cholesterol decreased by an average (95% confidence interval) of 12 (9 to 15)% and non-fasting triglyceride concentration by 43 (34 to 51)% during active treatment. Plasma prothrombin fragment F1 + 2 concentration, a marker of the in vivo rate of generation of thrombin, was 25 (12 to 37)% lower on average while on gemfibrozil than during the placebo phase. Factor VII coagulant activity (VIIc) and antigen concentration, and fibrinopeptide A concentration were not influenced by gemfibrozil in the group overall. However, the VIIc response appeared to be dependent upon the untreated cholesterol level. Hypercholesterolaemic men (cholesterol greater than 6.5 mmol/l) experienced a significant reduction in VIIc averaging 6% of standard during active therapy. Other effects of gemfibrozil were a 5 (2 to 9)% increase in plasma fibrinogen by a gravimetric method, an 11 (8 to 13)% increase in platelet count, and a 6 (2 to 10)% reduction in white cell count. The reduced incidence of CHD following gemfibrozil therapy in hyperlipidaemic patients may arise in part through a reduction in procoagulant activity and thus the risk of an occlusive coronary thrombosis.     

Increased mechanical fragility and intravascular lysis of erythrocytes in cats fed a propylene glycol-containing diet

The mechanism responsible for the decreased red blood cell (RBC) lifespan associated with feeding propylene glycol (PG)-containing diets was investigated to understand better how Heinz body-contained RBC are destroyed. Three cats were fed a diet containing 12% PG for 14 days and three other cats served as control. The experimental group developed reticulocytosis and increased Heinz body numbers. Red blood cell membrane immunoglobulih G (IgG) concentration and phagocytosis of RBC by peritoneal macrophages were lower in the PG group compared to the control group suggesting that neither IgG nor non-IgG-mediated phagocytosis was responsible for the RBC destruction. Osmotic fragility, rate of RBC proteolysis and mild mechanical fragility test results were not statistically different from controls. However, when RBC from cats fed PG were exposed to severe mechanical stress, their fragility were increased 2.2–2.8 times. Additionally, haptoglobin concentrations were decreased in the PG group. These data suggest that intravascular lysis may be involved in the pathogenesis of PG-induced RBC destruction.     

Variation in evoked potential measures over the menstrual cycle: A pilot study

Nancy Kluck, Scan J. O'Connor, Victor M. Hesselbrock, Allan Tasman and Donald Maier, Lance Bauer: Variation in Evoked Potential Measures Over the Menstrual Cycle: A Pilot Study. Prog. Neuro. Psychopharmacol. Biol. Psychiat. 1992. 16(6): 901–911.

1. 1. The P3 component of a visual event related potential (ERP) was studied for five consecutive weeks in six women with normal menstrual cycles. Serum concentrations of luteinizing hormone (LH), estradiol (E2) and progesterone were studied during the same period.

2. 2. Increases in P3 amplitude, although nonsignificant, were noted in the week preceding onset of menses.

3. 3. No significant changes in reaction times to target/nontarget stimuli were noted over the same time period.

Macroscopic geometric heterogeneity effects in radiation dose distribution analysis for boron neutron capture therapy.

Calculations of radiation flux and dose distributions for boron neutron capture therapy (BNCT) of brain tumors are typically performed using sophisticated three-dimensional analytical models based on either a homogeneous approximation or a simplified few-region approximation to the actual highly heterogeneous geometry of the irradiation volume. Such models should be validated by comparison with calculations using detailed models in which all significant macroscopic tissue heterogeneities and geometric structures are explicitly represented as faithfully as possible. This paper describes such a validation exercise for BNCT of canine brain tumors. Geometric measurements of the canine anatomical structures of interest for this work were performed by dissecting and examining two essentially identical Labrador retriever heads. Chemical analyses of various tissue samples taken during the dissections were conducted to obtain measurements of elemental compositions for the tissues of interest. The resulting geometry and tissue composition data were then used to construct a detailed heterogeneous calculational model of the Labrador head. Calculations of three-dimensional radiation flux distributions pertinent to BNCT were performed for this model using the TORT discrete-ordinates radiation transport code. The calculations were repeated for a corresponding volume-weighted homogeneous-tissue model. Comparison of the results showed that peak neutron and photon flux magnitudes were quite similar for the two models (within 5%), but that the spatial flux profiles were shifted in the heterogeneous model such that the fluxes in some locations away from the peak differed from the corresponding fluxes in the homogeneous model by as much as 10%-20%. Differences of this magnitude can be therapeutically significant, emphasizing the need for proper validation of simplified treatment planning models.     

Pericarditis constrictiva after aortic valve replacement simulating tricuspid stenosis.

Pericarditis constrictiva after cardiac surgery is rare and may occasionally lead to congestive heart failure. The case of a 29-year-old patient is described who presented with pericarditis constrictiva after aortic valve replacement with localized tamponade, causing functional tricuspid stenosis. Pericardiectomy as the treatment of choice was curative.