Investigation of an LC-MS-MS (QTrap) method for the rapid screening and identification of drugs in postmortem toxicology whole blood samples

The QTrap liquid chromatography-tandem mass spectrometry (LC-MS-MS) by Applied Biosystems was investigated as an adjund to enzyme immunoassay (EIA) for the rapid detection of drugs in blood. Thus, a procedure used to identify drugs in whole blood by EIA was extended to LC-MS-MS analysis. A multiple reaction monitoring (MRM) database of over 100 drugs was constructed to analyze for those drugs commonly observed in postmortem toxicology cases. The QTrap method provided for a scan time of only 2.8 s to produce both an MRM and an enhanced product ion scan. Various validation and developmental steps of the method are presented, as well as a concordance study as a final means of validation. This study was conducted to compare the effectiveness of the QTrap versus conventional extraction methods and gas chromatography-MS for the identification of drugs in 95 postmortem samples. The more than 400 drug results in this study showed 100% concordance between the two techniques.     

Posaconazole therapy for systemic coccidioidomycosis in a chimpanzee (Pan troglodytes): a case report

Systemic coccidioidomycosis was diagnosed in a 4-year-old male chimpanzee (Pan troglodytes) with ascites and failure to thrive. Physical examination, laboratory and radiological studies, and exploratory laparotomy showed signs of systemic fungal infection that included penetration into the central nervous system (CNS). Serum and cerebrospinal fluid (CSF) titres, along with ascites cytology findings, confirmed the presence of Coccidioides immitis. However, the organism could not be cultured from the CSF. Treatment with fluconazole 10 mg kg(-1) daily for 6 months was not associated with clinical improvement. Subsequent treatment with posaconazole 50 mg kg(-1) daily for approximately 24 months resulted in negative serum titres and improved clinical status. Illness not directly related to the C. immitis infection caused the chimpanzee's deterioration and eventual killing. Histological examination performed during necropsy provided no evidence of coccidioidomycosis; however, a positive C. immitis serum antibody titre was noted. The successful suppression of coccidioidomycosis observed in this chimpanzee suggests that posaconazole may have a role in the treatment of CNS infections caused by susceptible fungi.     

Drotrecogin Alfa (activated) Prevents Smoke-Induced Increases in Pulmonary Microvascular Permeability and Proinflammatory Cytokine IL-1β in Rats

In an established rat model of smoke inhalation injury, we conducted a dose-response study to examine the protective effects of Xigris^TM [drotrecogin alfa (activated) (DrotAA)], a recombinant form of human activated protein C (APC). DrotAA is a serine protease (55 kD molecular weight) with the same amino acid sequence and the glycosylation site as human plasma-derived APC. A total of 120 F344/NH rats (half each gender, approximately 175 g body weight) were randomly divided into five groups and exposed nose-only to air or diesel fuel smoke for 20 min. These rats were then i.v. administered with DrotAA in 0, 5, 10, and 20 mg/kg body weight, respectively, immediately following smoke exposure. Treatment with DrotAA significantly attenuated smoke inhalation injury in a dose-dependent manner at 2 hours after insult, as indicated by preserving microvascular permeability and proinflammatory cytokine IL-1 (but not TNF- and neuropeptide substance P) in bronchoalveolar lavage fluid (BALF). Moreover, the rats treated with 20 mg/kg of DrotAA had an improvement of the expiration phase of pulmonary dynamic compliance. At all dosages, however, DrotAA also significantly increased all phases of pulmonary resistance compared with either the controls or to smoke inhalation alone. Generally, these data suggest that DrotAA may exert an anti-inflammatory effect by inhibiting cytokine-mediated inflammatory amplification. However, additional studies following a clinical course are needed to confirm the maximum efficiency and possible side effects of this recombined human activated protein C.     

Racial and ethnic differences in time to acute reperfusion therapy for patients hospitalized with myocardial infarction

Context  Nonwhite patients experience significantly longer times to fibrinolytic therapy (door-to-drug times) and percutaneous coronary intervention (door-to-balloon times) than white patients, raising concerns of health care disparities, but the reasons for these patterns are poorly understood. Objectives  To estimate race/ethnicity differences in door-to-drug and door-to-balloon times for patients receiving primary reperfusion for ST-segment elevation myocardial infarction; to examine how sociodemographic factors, insurance status, clinical characteristics, and hospital features mediate racial/ethnic differences. Design, Setting, and Patients  Retrospective, observational study using admission and treatment data from the National Registry of Myocardial Infarction (NRMI) for a US cohort of patients with ST-segment elevation myocardial infarction or left bundle-branch block and receiving reperfusion therapy. Patients (73 032 receiving fibrinolytic therapy; 37 143 receiving primary percutaneous coronary intervention) were admitted from January 1, 1999, through December 31, 2002, to hospitals participating in NRMI 3 and 4. Main Outcome Measure  Minutes between hospital arrival and acute reperfusion therapy. Results  Door-to-drug times were significantly longer for patients identified as African American/black (41.1 minutes), Hispanic (36.1 minutes), and Asian/Pacific Islander (37.4 minutes), compared with patients identified as white (33.8 minutes) (P<.01 for all). Door-to-balloon times for patients identified as African American/black (122.3 minutes) or Hispanic (114.8 minutes) were significantly longer than for patients identified as white (103.4 minutes) (P<.001 for both). Racial/ethnic differences were still significant but were substantially reduced after accounting for differences in mean times to treatment for the hospitals in which patients were treated; significant racial/ethnic differences persisted after further adjustment for sociodemographic characteristics, insurance status, and clinical and hospital characteristics (P<.01 for all). Conclusion  A substantial portion of the racial/ethnic disparity in time to treatment was accounted for by the specific hospital to which patients were admitted, in contrast to differential treatment by race/ethnicity inside the hospital.      

Pulmonary dysplasia, Denys-Drash syndrome and Wilms tumor 1 gene mutation in twins

While a genetic basis for the association of developmental lung and kidney defects has been suspected, the involvement of specific genes in this process is under active investigation. We report such a possible genetic linkage present in identical twins with a mutant Wilms tumor (WT1) gene. Twin girls, born at 35 weeks gestation, manifested symptoms of congenital nephrotic syndrome, renal failure, and severe respiratory abnormalities refractory to assisted ventilation. Both died at 1 month of age. Renal biopsies and autopsy kidney tissue from both the girls revealed diffuse mesangial sclerosis (DMS). Autopsy lung tissue revealed pulmonary dysplasia and hypoplasia in both twins. The WT1 gene from renal tissue in both twins was analyzed for mutations using polymerase chain reaction (PCR) amplification and the single-strand conformation polymorphism (SSCP) technique. Both twins possessed an identical missense mutation in exon 8 of the WT1 gene, resulting in replacement of arginine by histidine at amino acid 366 (arg366his) in the WT1 protein. This mutation has previously been described in Denys-Drash syndrome. The WT1 gene plays a role in mesenchymal epithelial (ME) interactions in the developing urogenital system, and possibly has a similar role during lung morphogenesis. We propose that this WT1 gene mutation contributes to both DMS and developmental pulmonary abnormalities by altering ME interactions in both organs. Received: 13 June 2000 / Revised: 1 November 2000 / Accepted: 2 November 2000     

Why do students choose careers in surgery?

Background: Recent changes in medical education have emphasized primary care careers. This could have a negative impact on the number of applicants to surgical residencies. We sought to determine what factors influenced medical students in choosing surgical careers. Methods: Third year medical students who completed their surgical clerkship in the 2001-2002 academic year (n = 83) were surveyed pre-and post- surgical clerkship. Responses were analyzed and correlated to the 2003 match results. Results: The response rate of students surveyed was 98%. Pre-clerkship, 6/82 students (7%) expressed an interest in surgery or surgical subspecialty careers. Post-clerkship, 34/84 students (40%) expressed an increased interest in a surgical career; 13/84 (15%)expressed a decreased interest, and 37% of students expressed no change in career interest. Of those students expressing an increased interest in surgery, the clerkship experiences most noted to be influential were (1) number of cases participated/scrubbed (95%), (2) resident interaction (85%), (3) faculty interaction (80%), and (4) number of cases observed (65%) (p < 0.05). The number of hours spent on rotation (call, rounds) was the leading experience associated with a decreased interest in a surgical career (p < 0.05). 12/83 students surveyed (14%) ultimately matched into a surgical program (NRMP 2003 match results). Conclusions: These data suggest that operative exposure and interaction with residents and faculty have a positive influence in students’ choice of a surgical career. Although only 6% of students expressed an interest in surgery pre-clerkship, a two-fold increase in this number was noted in choice of residency (14%). Work hours were the primary negative indicator for surgery residency. As medical curriculum is restructured and surgical exposure decreased, these data underscore the importance of quality exposure to both procedures and role models during the 3^rd year surgical clerkship.     

Preparation of biologically active ristocetin derivatives: replacements of the 1'-amino group

A series of ristocetin analogues with modifications (OH, C=O, C=NOH, NCOCH3) at the C-1' amino group was synthesized and found to possess antibacterial activity against gram-positive bacteria and to bind to Ac2-Lys-D-Ala-D-Ala, a model for the antibiotic's site of action. Due to the lack of a positively charged amino group, the active analogues could not form a salt bridge, indicating that an electrostatic interaction between the positively charged 1'-amino group of ristocetin and the carboxylate anion of the peptide is not required for complex formation. The only compound that did not exhibit good antibacterial activity was epiristocetin aglycone (an analogue with the 1'amino group in the opposite configuration (S) as ristocetin). On the basis of NMR studies of epiristocetin aglycone in solution, the 1'-amino group is located in the proposed carboxylate binding pocket and may sterically block complex formation.