Use of chiral liquid chromatography-tandem mass spectrometry to investigate the metabolism of racemic cholecystokinin-B antagonists

In an attempt to establish the enantiomeric specificity of metabolism for a series of racemic cholecystokinin-B receptor antagonists, chiral LC-MS-MS conditions were established using a Pirkle DNBL chiral stationary phase operating in the reversed-phase mode. Rat liver microsomal incubations of the compounds were analysed using these conditions and it was demonstrated that resolution of oxygenated and demethylated metabolites could be achieved. A single model compound was investigated in detail by obtaining product-ion spectra on all mono-oxygenated species in an attempt to correlate these and identify enantiomeric pairs of metabolites. In this example a lack of differentiation in the product ion spectra did not allow correlation but the results suggest that such an approach may still be viable for the chiral metabolic analysis of racemic material.

Three-pion interferometry results from central Pb+Pb collisions at 158A GeV/c

Three-particle correlations have been measured for identified pi(-) from central 158A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.

Decreased quality of peripheral blood progenitors collected after a peripheral blood progenitor transplant

The purpose of this study was to determine the quality of peripheral blood progenitor cells (PBPC) collected after an initial autologous PBPC transplant. Tandem autologous transplants have been used in the treatment of several malignancies. Routinely, PBPC have been collected prior to the first transplant and used for both transplants. In the current study, PBPC harvested prior to the first high-dose therapy (HDT) were used as a source of progenitors for transplant 1, and a combination of bone marrow harvested prior to the first course of HDT and PBPC collected approximately 85 days after the first transplant were used to support the second HDT. We analyzed the quality of the PBPC collected 85-120 days after HDT and autologous PBPC transplant. CD34 and colony-forming units granulocyte-macrophage (CFU-GM) contents of those collections were poor, and hematopoietic recovery was more consistent with recovery from a bone marrow transplant than a PBPC transplant. Thirteen of 15 patients received both transplants. Days to absolute granulocyte count of 500 was 10 +/- 1.5 for the first transplant and 13.3 +/- 3.7 for the second (p < 0.01). The number of days to platelet count of 20,000 was 14.3 +/- 10.7 for the first transplant and 18 +/- 7 for the second transplant (p = 0.066). The number of days of total parenteral nutrition (TPN) and intravenous morphine used by patients for the first and second transplants was similar, whereas the length of hospitalization was 21.8 +/- 3.6 for the first transplant and 27.6 +/- 7.8 for the second transplant (NS). In conclusion, it appears that the quality of PBPC collected following a previous PBPC transplant may be compromised.

Origins of Staphylococcus epidermidis and Streptococcus oralis causing bacteraemia in a bone marrow transplant patient

Coagulase-negative staphylococcal bacteraemia in immunocompromised patients is often associated with the use of central venous catheters, while the proposed origin of viridans streptococci causing bacteraemia in this patient group is the oral cavity. This report describes an episode of polymicrobial bacteraemia caused by Staphylococcus epidermidis and Streptococcus oralis followed by several further episodes of S. epidermidis bacteraemia in a 15-year-old boy after bone marrow transplantation. Pulsed-field gel electrophoresis (PFGE) of SmaI chromosomal DNA digests was used to compare blood culture and oral isolates of S. epidermidis and Str. oralis. The results indicated that the mouth was the source of both S. epidermidis and Str. oralis causing the first episode of bacteraemia. PFGE further demonstrated that the central venous catheter was the origin of a second strain of S. epidermidis responsible for subsequent episodes of staphylococcal bacteraemia. Both the oral mucosa and central venous lines should be considered as potential sources of organisms, including coagulase-negative staphylococci, associated with bacteraemia in immunocompromised patients.

Large lung bullae in marijuana smokers

The case histories are presented of four men with multiple large upper zone lung bullae but otherwise relatively preserved lung parenchyma. Each had a history of significant exposure to marijuana. In three of the four cases the tobacco smoking load had been relatively small, suggesting a possible causal role for marijuana in the pathogenesis of this unusual pattern of bullous emphysema.

Plasmid-mediated vanB glycopeptide resistance in enterococci

Enterococcus faecium, which was highly resistant to vancomycin (MIC 256 mg/liter), but susceptible to teicoplanin (MIC 2 mg/liter), caused two distinct episodes of infection on a renal unit in the United Kingdom. Pulsed field gel electrophoresis (PFGE) indicated that a single strain caused the first episode, while the second episode, which occurred 1 year later, involved multiple strains, all of which were distinct from the original strain. Vancomycin resistance in all but one of these strains was mediated by transferable plasmids that carried the vanB glycopeptide resistance gene. Transfer either of resistance plasmids or the vanB resistance determinant itself to different strains occurred during the second episode. Plasmid-mediated vanB resistance has not been widely documented. A retrospective study of a reference collection revealed two other vanB-encoding plasmids from an E. faecalis and an E. faecium referred from two further UK centers. Although restriction analysis indicated no similarity between the plasmids from the three different centers, all contained a 2.1-kb EcoRV fragment that hybridized with a probe for the vanB gene. This suggests that there has been dissemination of a conserved glycopeptide resistance determinant, of which vanB is a part.

Higher throughput bioanalysis by automation of a protein precipitation assay using a 96-well format with detection by LC-MS/MS

Generic methodology for the automated preparation and analysis of drug levels in plasma samples within a drug discovery environment was achieved through the redesign of a protein precipitation assay to a microtiter (96-well) plate format and the application of robotic liquid handling for performance of all transfer and pipetting steps. Validation studies revealed that the application of robotics to sample preparation, in general, maintained the analytical accuracy and precision compared with preparing samples manually. The use of rapid gradient LC-MS/MS for analysis coupled with flow diversion of the solvent front allowed the introduction of protein-precipitated samples into the mass spectrometer without the necessity for source cleaning. The problem inherent in automatically pipetting plasma, caused by fibrinogen clots, was overcome by storing samples at -80 degrees C and thus precluding clot formation. The resulting methodology allowed sample preparation for a 96-well plate designed to accommodate 54 unknowns, duplicate 12-point calibration curves, and 6 sets of quality controls at three levels in approximately 2 h. This approach allowed an increase in throughput of sample preparation and analysis to >400 samples per day per LC-MS/MS instrument with minimal manual intervention. Overall, substantial time savings were realized, demonstrating that automation is an increasingly essential tool in a drug discovery bioanalytical environment.

Hinged mandibular removable complete denture for post-mandibulectomy patients

The presence of excessive lingual undercuts after mandibulectomy and surgical reconstruction is a rare clinical condition and presents unique prosthodontic challenges. The goals of prosthodontic treatment include: providing lip support, improving articulation, reducing drooling, and regaining favorable esthetics. This article describes the fabrication of a hinged removable mandibular complete denture prosthesis using a sectional impression tray technique and a custom-made hinge mechanism. Clinical and laboratory procedures of the prosthetic treatment are described, and the advantages and disadvantages are reviewed.

Fluorination of 3-(3-(piperidin-1-yl)propyl)indoles and 3-(3-(piperazin-1-yl)propyl)indoles gives selective human 5-HT1D receptor ligands with improved pharmacokinetic profiles

It has previously been reported that a 3-(3-(piperazin-1-yl)propyl)indole series of 5-HT1D receptor ligands have pharmacokinetic advantages over the corresponding 3-(3-(piperidin-1-yl)propyl)indole series and that the reduced pKa of the piperazines compared to the piperidines may be one possible explanation for these differences. To investigate this proposal we have developed versatile synthetic strategies for the incorporation of fluorine into these ligands, producing novel series of 4-fluoropiperidines, 3-fluoro-4-aminopiperidines, and both piperazine and piperidine derivatives with one or two fluorines in the propyl linker. Ligands were identified which maintained high affinity and selectivity for the 5-HT1D receptor and showed agonist efficacy in vitro. The incorporation of fluorine was found to significantly reduce the pKa of the compounds, and this reduction of basicity was shown to have a dramatic, beneficial influence on oral absorption, although the effect on oral bioavailability could not always be accurately predicted.

Using a facsimile (fax) as an aid for communication in maxillectomy planning between the prosthodontist and surgeon

Preoperative communication between the prosthodontist and surgeon is required for properly planning the surgical prostheses that are often indicated for maxillectomy patients. When geography or long distances preclude face-to-face consultation, electronic means of correspondence are necessary to minimize delays in the fabrication of surgical prostheses. This article presents a time-efficient procedure for facilitation of the necessary communication between the prosthodontist and surgeon before maxillectomy surgical procedures.

DNA banding pattern polymorphism in vancomycin-resistant Enterococcus faecium and criteria for defining strains

The degree of DNA banding pattern polymorphism exhibited by vancomycin-resistant Enterococcus faecium (VREM) strains isolated on a renal unit over an 11-month period was investigated. Thirty VREM strains from different patients were analyzed by pulsed-field gel electrophoresis (PFGE; with extended run and optimal pulse times), ribotyping, plasmid profile analysis, biotyping, pyrolysis mass spectrometry, and antibiogram analysis. PFGE resolved 17 banding patterns which formed four distinct clusters at the 82% similarity level. Intercluster band differences ranged from 14 to 31 bands. The strains in one cluster, which contained seven patterns that differed from each other by one to seven bands and from the common pattern by five bands, were confirmed to be a single strain by four of the five other typing methods. The strains in a second cluster with eight patterns, which differed from each other by 1 to 12 bands, contained two subclusters. This subdivision was supported by ribotyping and biotyping. However, it was unclear whether these subclusters represented distinct strains. In one strain, marked polymorphism (patterns that differed from each other by up to four bands) was observed in the ribotype pattern. This study demonstrates the high degree of DNA banding pattern polymorphism found for some strains of VREM and illustrates the complexity involved in defining such strains.

External validation of the Ottawa knee rules in an urban trauma center in the United States

OBJECTIVE

We evaluated the Ottawa knee rules in a high-volume teaching hospital in the United States to determine whether the rules could be safely used to decide whether patients with acute blunt knee trauma should undergo radiography.

SUBJECTS AND METHODS

During a 13-month period, 378 patients with acute blunt knee trauma were prospectively examined using the Ottawa knee rules. Data collected included the presence or absence of fracture predictors and the results of radiography.

RESULTS

A fracture was seen in 43 (11%) of the 378 patients who met inclusion criteria. The knee rules predicted 42 of the 43 fractures; sensitivity was 98%, and specificity was 19%. Radiography of 65 patients (17%) who had no predictors for fracture could have been avoided if the knee rules had been used to screen for radiography.

CONCLUSION

The Ottawa knee rules are highly sensitive for fracture in this setting and may safely be used to decide whether patients with acute blunt knee trauma should undergo radiography.

Epithelial permeability, inflammation, and oxidant stress in the air spaces of smokers

The mechanism responsible for the increased air-space permeability in cigarette smokers is unknown. The aim of this study was to assess the acute and chronic effects of cigarette smoking on epithelial permeability, inflammation, and oxidant stress in the air spaces of smokers. Fourteen cigarette smokers underwent 99mTc-diethylenetriamine pentaacetic acid (99mTc-DTPA) lung scans after abstaining from smoking for 12 h (chronic smoking) and 1 h after smoking two cigarettes (acute smoking). Each smoker also underwent bronchoscopy and bronchoalveolar lavage (BAL) after either chronic (n = 8) or acute smoking (n = 7). Seven nonsmokers also underwent bronchoscopy and BAL. The time to 50% clearance of 99mTc-DTPA (t50) after chronic smoking was 16.7 +/- 1. 3 min (mean +/- SE), and was further reduced after acute smoking to 14.8 +/- 1.0 min (p < 0.01). Neutrophil numbers were increased in bronchoalveolar lavage fluid (BALF) in the acute smoking group as compared with the nonsmokers (p < 0.05). Superoxide release from mixed BAL leukocytes was increased after chronic (p < 0.01) and acute (p < 0.001) smoking, as were thiobarbituric acid-reactive species (TBARS), providing evidence of lipid peroxidation in plasma (chronic, p < 0.05; acute, p < 0.05). Trolox equivalent antioxidant capacity (TEAC) was reduced in plasma (p < 0.001) and increased in BALF (p < 0.05) in both smoking groups. The study therefore showed an acute increase in epithelial permeability and an increase in the number of neutrophils in the air spaces of cigarette smokers concomitant with evidence of increased oxidant stress.

Effects of hypoxia on renal hormonal balance in normal subjects and in patients with COPD

There is a complex interaction between pulmonary haemodynamics, hormonal, and salt and water balance in patients with chronic obstructive pulmonary disease (COPD) and in normal subjects exposed to hypoxia or high altitude. This study aims to investigate the effects of hypoxia on renal hormonal balance in normal subjects and patients with COPD, particularly the role of urinary dopamine and atrial natriuretic peptide (ANP). Urinary dopamine output, ANP, and plasma renin activity (PRA) were measured in 12 normal subjects exposed to hypoxia (12% O2) and hyperoxia (40% O2) for 1 h and in 15 patients with exacerbations of COPD while breathing air or O2. These measurements were repeated in six of the patients with exacerbations of COPD when they were clinically stable. Hypoxia caused an increase in ANP levels (49 +/- 6-62 +/- 6 pg ml-1, P < 0.05) and a fall in urinary dopamine output (277 +/- 39-205 +/- 33 ng h-1, P < 0.002) in normal subjects. Hyperoxia was associated with a return of plasma ANP to the baseline values. In patients with exacerbations of COPD plasma ANP levels were higher (181 +/- 36 pg ml-1) than in normal subjects (49.5 +/- 6.5 pg ml-1, P < 0.001). Urinary dopamine output breathing air (175 +/- 34 ng h-1) was similar to the levels when normal subjects were made hypoxaemic and PRA was elevated in comparison to normal values. There was no change in their levels following the acute administration of oxygen in patients presenting with exacerbations of COPD, but oxygen improved urinary sodium excretion (P < 0.05). In six patients re-studied when clinically stable there was a fall in urinary dopamine output, plasma ANP and PRA when breathing air in comparison to the acute stage of the disease (P < 0.05). These data suggest presence of renal hormonal imbalance including endogenous urinary dopamine output during hypoxic exacerbation of COPD and in normal subjects exposed to hypoxia.

Neutrophil chemokines in bronchoalveolar lavage fluid and leukocyte-conditioned medium from nonsmokers and smokers

Polymorphonuclear neutrophils (PMN) have been implicated in the pathogenesis of emphysema. The chemokines interleukin-8(IL-8), growth-related oncogene (GRO-alpha) and extractable nuclear antigen (ENA)-78 may be involved in the increased numbers of PMN in smokers' airspaces. The levels of these cytokines in bronchoalveolar lavage fluid (BALF) and bronchoalveolar lavage leukocyte conditioned medium (LCM), along with BALF PMN numbers in 12 smokers who abstained for 12 h (chronic smoking) or continued to smoke until I h before study (acute smoking) and seven nonsmokers were compared. Neutrophils in BALF increased in acute (1.96+/-0.53%, 0.99+/-0.32x10(6) cells) compared with chronic smokers (0.59+/-0.25%, 0.61+/-0.24x10(6) cells, p<0.05 nonsmokers) and nonsmokers (0.79+/-0.29%, 0.05+/-0.01x 10(6) cells, p<0.05). There were no differences in IL-8 or GRO-alpha in BALF between smokers and nonsmokers. ENA-78 levels were lower in smokers (p=0.006). There was no difference in IL-8, GRO-alpha or ENA-78 in LCM from unstimulated cells in smokers versus nonsmokers. After stimulation with lipopolysaccharide (LPS) 10 ng mL(-1), IL-8 release in acute smokers (p=0.04) and GRO-alpha release in smokers (p=0.009) were significantly higher than in nonsmokers. Following stimulation with LPS 100 ng.mL(-1), GRO-alpha release was higher in smokers (p=0.03) and increased further in acute smokers (p=0.02 versus nonsmokers, p=0.04 versus chronic smokers) and ENA-78 release increased in smokers (p=0.02 versus non-smokers). In conclusion, influx of polymorphonuclear neutrophils into smokers' airspaces is an acute phenomenon and neutrophil chemokine release from mixed bronchoalveolar lavage leukocytes is influenced by cigarette smoking and endotoxins.

1997 Judson C. Hickey Scientific Writing Awards. Lip prosthesis retained with resin-bonded retentive elements as an option for the restoration of labial defects: a clinical report

Surgical resection of the lips is a relatively uncommon procedure, and it usually presents surgical and prosthodontic rehabilitation challenges. The goals of prosthetic treatment include regaining favorable speech and restoration of esthetics. This clinical report described a method for fabricating a lip prosthesis that uses resin-bonded retentive elements bonded to the patient's teeth for retention. Clinical and laboratory procedures of the prosthetic treatment were described, and the advantages and disadvantages were reviewed.

The hyperresponsiveness of cells expressing truncated erythropoietin receptors is contingent on insulin-like growth factor-1 in fetal calf serum

We demonstrate herein that the well documented hyperresponsiveness to erythropoietin (Epo) of Ba/F3 cells expressing C-terminal truncated erythropoietin receptors (EpoRs) is contingent on these cells being in fetal calf serum (FCS). In the absence of FCS, their Epo-induced proliferation is far poorer than Ba/F3 cells expressing wild-type (WT) EpoRs. This hyporesponsiveness in the absence of serum is also seen in DA-3 cells expressing these truncated EpoRs. In fact, long-term proliferation studies performed in the absence of serum show that even at saturating concentrations of Epo, Ba/F3 cells expressing these truncated receptors die via apoptosis, while cells bearing WT EpoRs do not, and this programmed cell death correlates with an inability of Epo-stimulated Ba/F3 cells expressing truncated EpoRs to induce the tyrosine phosphorylation of MAPK and the activation of p70(S6K). Using neutralizing antibodies to insulin-like growth factor (IGF)-1, we show that a major non-Epo factor in FCS that contributes to the hyperresponsive phenotype of Ba/F3 cells expressing truncated EpoRs is IGF-1. Our results suggest that the Epo-hypersensitivity of truncated EpoR expressing Ba/F3 cells is due to the combined effects of these EpoRs not possessing a binding site for the negative regulator, SHP-1, and the triggering of proliferation-inducing/apoptosis-inhibiting cascades, lost through EpoR truncation, by IGF-1.