Empirical antibacterial therapy in febrile, granulocytopenic bone marrow transplant patients

Fifty febrile, granulocytopenic allogeneic bone marrow transplant patients receiving prophylactic trimethoprim-sulfamethoxazole were randomized to one of two empirical antibiotic regimens to determine whether a shortened course of empirical therapy was beneficial. Of the 50 patients, 25 received empirical tobramycin and ticarcillin for only 3 days, and 25 were maintained on empirical tobramycin and ticarcillin until they were afebrile and no longer granulocytopenic. Although the incidence of bacterial infections in the two groups was not statistically significantly different, almost twice as many bacterial infections were observed in the group that received the short course of empirical therapy. Furthermore, because of the high incidence of bacterial infection and clinical concerns about occult bacterial sepsis, within 2 weeks of the randomization the overall use of parenteral antibacterial agents was similar in both groups. The incidence of invasive fungal disease and the use of amphotericin B therapy were similar in both groups. The results of this study suggest that little clinical benefit is likely to be seen in bone marrow transplant patients treated with short-course empirical tobramycin and ticarcillin, despite the administration of prophylactic trimethoprim-sulfamethoxazole, and emphasize the need for new strategies to prevent infections with gram-positive and trimethoprim-sulfamethoxazole-resistant gram-negative bacteria in these patients.     

Cassane diterpenoids of Caesalpinia pulcherrima

Five new cassane diterpenoids (1-5) were isolated from the roots of Caesalpinia pulcherrima, along with the known isovouacapenol C (6), pulcherrimin A (11), and 6beta-cinnamoyl-7beta-hydroxyvouacapen-5alpha-ol (12). Compounds 3-5 possess the alpha,beta-butenolide moiety, whereas compounds 1 and 2 contain a more usual 2,3-disubstituted furan unit. Compounds 7 and 8 were derived from hydrolysis of 6, while 9 and 10 were derived from acetylation and oxidation of 6, respectively. The (1)H and (13)C NMR spectra of all compounds were completely assigned using a combination of 2D NMR experiments, including (1)H-(1)H COSY, HSQC, HMBC, and T-ROESY sequences.     

Muscle tissue oxygenation and VEGF in VO2‐matched vibration and squatting exercise

Exposure to vibration has traditionally been associated with compromised perfusion. This study investigated whether blood supply during whole body vibration (WBV), as an exercise modality, is in proportion to the metabolic demand by the contracting musculature. As a secondary aim, serum levels of vascular endothelial growth factor (VEGF) were assessed. Ten young healthy males performed WBV and dynamic shallow squatting (Squat) exercise at comparable levels of oxygen uptake for 3 min. Changes in oxygenated, deoxygenated and total haemoglobin (O₂Hb, HHb and tHb, respectively) along with tissue oxygenation index (TOI) were measured continuously before, during and after the exercise by near‐infrared spectroscopy (NIRS, Portamon, Artinis Medical Systems, Zetten, The Netherlands). Vascular endothelial growth factor‐A blood levels before and after exercise were assessed by ELISA. Oxygen uptake was comparable in Squat and WBV (11·4 and 10·7 ml kg^?1 min^?1), respectively, P = 0·49), as were all other cardiopulmonary variables. Near‐infrared spectroscopy data were found to be non‐stationary during and shortly after WBV, but stationary in Squat. There was an increase in O₂Hb and TOI, and a decrease in HHb during the first 30 s of WBV, but no significant change was observed during Squat. No group difference was found in VEGF serum levels. These results suggest that oxygen supply during WBV is sufficient, and oxygenation is even enhanced during the first approximately 30 s. Most likely, the transient response is because of local vascular regulatory mechanisms and due to muscle contraction mechanics. This might become clinically relevant under pathological conditions, e.g. in vascular disorders.     

Doctors' perceptions of laboratory monitoring in office practice

Background Laboratory monitoring has been increasingly recognized as an important area for improving patient safety in ambulatory care. Little is known about doctors' attitudes towards laboratory monitoring and potential ways to improve it. Methods Six focus groups and one individual interview with 20 primary care doctors and nine specialists from three Massachusetts communities. Results Participants viewed laboratory monitoring as a critical, time‐consuming task integral to their practice of medicine. Most believed they commit few laboratory monitoring errors and were surprised at the error rates reported in the literature. They listed various barriers to monitoring, including not knowing which doctor was responsible for ensuring the completion of laboratory monitoring, uncertainty regarding the necessity of monitoring, lack of alerts/reminders and patient non‐adherence with recommended monitoring. The primary facilitator of monitoring was ordering laboratory tests while the patient is in the office. Primary care doctors felt more strongly than specialists that computerized alerts could improve laboratory monitoring. Participants wanted to individualize alerts for their practices and warned that alerts must not interrupt work flow or require too many clicks. Conclusions Doctors in community practice recognized the potential of computerized alerts to enhance their monitoring protocols for some medications. They viewed patient non‐adherence as a barrier to optimal monitoring. Interventions to improve laboratory monitoring should address doctor workflow issues, in addition to patients' awareness of the importance of fulfilling recommended therapeutic monitoring to prevent adverse drug events.     

Inactivation of the retinoblastoma susceptibility gene in a human high grade non-Hodgkin''s lymphoma cell line

We studied the expression of the retinoblastoma (RB) gene product (p105) in a B-cell line established from a patient with non-Hodgkin's lymphoma (large cell type). The karyotype of this cell line, named Ri-1, showed amongst other changes an apparent deletion of one chromosome 13 on band q14. No p105 could be detected by immunoprecipitation analysis and Western blotting in Ri-1 cells. Northern blotting revealed that RB mRNA is not expressed in Ri-1. Southern blotting confirmed the loss of one RB allele but showed a normal gross structure of the remaining allele. This suggests that the inactivation of the RB gene in Ri-1 cells is due to deletion of one allele and point mutations or small deletions in the other, as is often the case in retinoblastomas. Our findings imply that inactivation of the RB gene may play a role in the pathogenesis of high grade malignant lymphomas and that studies of RB in primary lymphoma samples would be of interest.     

Genotypic analysis of Mycobacterium tuberculosis in Bangladesh and prevalence of the Beijing strain

Genotypic analysis was performed on 48 Mycobacterium tuberculosis complex strains collected from a hospital in Dhaka city. Deletion analysis showed that the isolates were all M. tuberculosis; 13 of them were found to be of the "ancestral" type, while 35 were of the "modern" type, indicating that both endemic (ancestral type) and epidemic (modern type) strains cause tuberculosis in Bangladesh. Genotyping based on the spoligotype and variable-number tandem repeats (VNTR) of mycobacterial interspersed repetitive units (MIRU) was also done. A total of 34 strains (71%) were grouped by spoligotyping into nine different clusters; the largest comprised 15 isolates of the Beijing genotype, whereas the remaining eight clusters consisted of two to five isolates. MIRU-VNTR typing detected 32 different patterns among 44 tested strains, and the 15 Beijing strains were further discriminated by MIRU-VNTR typing (7 distinct patterns for the 15 isolates). These results indicate that MIRU-VNTR typing, along with spoligotyping and deletion analysis, can be used effectively for molecular epidemiological studies to determine ongoing transmission clusters; to our knowledge, this is the first report about the type of strains prevailing in Bangladesh.     

Stable micro-dystrophin gene transfer using an integrating adeno-retroviral hybrid vector ameliorates the dystrophic pathology in mdx mouse muscle

The ability to transfer the dystrophin gene stably to the skeletal muscle of DMD patients is a major confounding issue in establishing an effective gene therapy for this disease. To overcome this problem, we have examined the ability of muscle fibres from mdx mice to act as in situ factories of retroviral vector production. Tibialis anterior (TA) muscles from 4-week-old mdx mice were injected with an adenoviral vector expressing LacZ within a retroviral expression cassette (AdLZIN). Retroviral vector production was induced by the inclusion of two additional adenoviral vectors expressing retroviral gag-pol (AdGagPol) and 10A1 env genes (Ad10A1). Upon introduction of infected muscles into cell culture, colonies of beta-galactosidase-expressing myotubes formed only in cultures where the muscle was injected with AdLZIN, AdGagPol and Ad10A1, but not from muscle injected with AdLZIN only. Muscles from mdx/nude mice producing retroviral vector displayed a 4.6-fold increase in beta-galactosidase-positive myofibres after 1 month, compared with contralateral muscle in the same animal injected with AdLZIN and AdGagPol only. By constructing a hybrid adeno-retroviral vector expressing a truncated micro-dystrophin construct (AdmicroDyIN), we were able to partially correct the mdx dystrophic phenotype. AdmicroDyIN-mediated expression of micro-dystrophin in mdx TA muscle restored the formation of the dystrophin-associated glycoprotein complex and significantly reduced the level of muscle degeneration over uninjected controls. By stimulating in situ production of retroviral vector expressing micro-dystrophin, we achieved 92%+/-6% transduction of myofibres in the TA muscle by 4 weeks. Strikingly, by 3 months post injection, micro-dystrophin was still expressed to high levels in nearly all the myofibres of the TA muscle. By comparison, there was a pronounced drop in the levels of micro-dystrophin expressed by muscles injected with AdmicroDyIN only. Finally, using a novel PCR approach, we detected reverse-transcribed, integrated proviral sequences in TA muscle genomic DNA by 4 weeks post injection, the levels of which were found to increase after 3 months.     

Serum concentrations of oestradiol-17beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey

The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.