Pharmacoeconomics of intravenous antibiotic use in serious infection

A pharmacoeconomic study of 15 antibiotics available in Barbados was performed. The antibiotics studied were amoxycillin/clavulanate, ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, ceftazidime, ceftriaxone, clindamycin, cloxacillin, cotrimoxazole, gentamicin, imipenem, metronidazole, piperacillin, piperacillin/tazobactam, and vancomycin. The costs of use of these compounds were calculated for a five-day course using a formula comprising eight categories: antibiotic purchase cost, maintenance of intravenous access, drug delivery cost, drug monitoring cost, dose readjustment, general monitoring cost, 'sharps' disposal cost and adverse effects. The costs of adverse effects were not included in this study due to lack of accurate data. The total cost of antibiotic use (in U.S. dollars) ranged from $42.52 to $463.73 per five-day course. Generic compounds were less expensive ($45.52 - $98.23) than brand-name compounds ($106.18 - $106.18 - $463.73). Antibiotic purchase costs accounted for proportions of total costs ranging from 7 to 93%. Non-drug costs represented a much greater proportion of total costs of generic compounds. For most compounds the non-drug costs were related to the frequency of dosing, but for gentamicin the non-drug costs were relatively higher because of the need for monitoring of serum gentamicin levels. Efficacy and freedom from side-effects will remain the most important determinants in the choice of antibiotic therapy. However, pharmacoeconomic analyses can provide prescribers with the information required to make cost-effective choices for treatment of their patients.     

An examination of spatial variation in mercury concentrations in otter (Lutra canadensis) in south-central Ontario

Hair samples were collected from otter (Lutra canadensis) trapped in several parts of south-central Ontario, Canada. The concentrations of total Hg in hair were compared with methyl mercury concentrations in liver tissues from the same individuals to determine if hair is a suitable monitoring tissue. Hg in the two tissues was significantly correlated. Hair was used to monitor Hg in 51 individuals from four townships. The concentrations of total Hg in hair ranged from 4 to 20 micrograms/g. No significant variation among the four sample regions existed. Generally the highest concentrations were found in the youngest members of the population. Some possible explanations for the observations are presented.     

The effect of the addition of adrenaline to pethidine for patient-controlled epidural analgesia after caesarean section

We have investigated the addition of adrenaline to pethidine for patient-controlled epidural analgesia after elective Caesarean section. In a randomised, double-blind study, patients received patient-controlled epidural analgesia for 24 h using pethidine 5 mg.ml-1 with adrenaline 5 micrograms.ml-1 (adrenaline group, n = 40) or pethidine 5 mg.ml-1 without adrenaline (plain group, n = 38). Visual analogue scale pain scores at rest and on coughing measured 2 h, 6 h and 24 h after surgery were similar between the two groups. There was a trend towards lower mean total consumption of pethidine in the adrenaline group (231.5 mg; SD 140.5 mg) compared with the plain group (289.5 mg; SD 139.5 mg; p = 0.071). Patients in the adrenaline group had higher visual analogue scale scores for nausea at 2 h and 24 h and higher scores for pruritus at 2 h compared with the plain group. Addition of adrenaline to pethidine for patient-controlled epidural analgesia does not appear to have significant clinical advantages.     

Comparison of the intrinsic kinase activity and substrate specificity of c-Abl and Bcr-Abl

We studied the intrinsic tyrosine kinase activity and substrate specificity of c-Abl and Bcr-Abl protein tyrosine kinases (PTKs) using the peptide substrates discovered from a synthetic combinatorial peptide library. Our data indicate that the phosphorylation of these peptides by Bcr-Abl was consistently stronger than that by c-Abl. Bcr-Abl also showed substrate preference towards those peptides with one or more positive charges.     

Telomere length regulation in mice is linked to a novel chromosome locus

Little is known about the mechanisms that regulate species-specific telomere length, particularly in mammalian species. The genetic regulation of telomere length was therefore investigated by using two inter-fertile species of mice, which differ in their telomere length. Mus musculus (telomere length >25 kb) and Mus spretus (telomere length 5-15 kb) were used to generate F1 crosses and reciprocal backcrosses, which were then analyzed for regulation of telomere length. This analysis indicated that a dominant and trans-acting mechanism exists capable of extensive elongation of telomeres in somatic cells after fusion of parental germline cells with discrepant telomere lengths. A genome wide screen of interspecific crosses, using M. spretus as the recurrent parent, identified a 5-centimorgan region on distal chromosome 2 that predominantly controls the observed species-specific telomere length regulation. This locus is distinct from candidate genes encoding known telomere-binding proteins or telomerase components. These results demonstrate that an unidentified gene(s) mapped to distal chromosome 2 regulates telomere length in the mouse.     

Carcinoma of the tonsillar fossa: prognostic factors and long-term therapy outcome

PURPOSE: To identify prognostic parameters and evaluate the therapeutic outcomes for patients with carcinoma of the tonsillar fossa treated with three treatment modalities. METHODS AND MATERIALS: The results of therapy are reported in 384 patients with histologically proven epidermoid carcinoma of the tonsillar fossa; 154 were treated with irradiation alone (55-70 Gy), 144 with preoperative radiation therapy (20-40 Gy), and 86 with postoperative irradiation (50-60 Gy). The operation in all but four patients in the last two groups consisted of an en bloc radical tonsillectomy with ipsilateral lymph node dissection. RESULTS: Treatment modality and total irradiation doses had no impact on survival. Actuarial 10-year disease-free survival rates were 65% for patients with T1 tumors, 60% for T2, 60% for T3, and 30% for T4 disease. Patients with no cervical lymphadenopathy or with a small metastatic lymph node (N1) had better disease-free survival (60% and 70%, respectively) at 5 years than those with large or fixed lymph nodes (30%). Primary tumor recurrence (local, marginal) rates in the T1, T2, and T3 groups were 20-25% in patients treated with irradiation and surgery and 31% for those treated with irradiation alone (difference not statistically significant). In patients with T4 disease treated with surgery and postoperative irradiation, the local failure rate was 32% compared with 86% with low-dose preoperative irradiation and 47% with irradiation alone (p = 0.03). The overall recurrence rates in the neck were 10% for N0 patients, 25% for N1 and N2, and 35-40% for patients with N3 cervical lymph nodes, without significant differences among the various treatment groups. The incidence of contralateral neck recurrences was 8% with the various treatment modalities. On multivariate analysis the only significant factors for local tumor control and disease-free survival were T and N stage (p = 0.04-0.001). Fatal complications were noted in 7 of 144 (5%) patients treated with preoperative irradiation and surgery, 2 of 86 (2%) of those receiving postoperative irradiation, and 2 of 154 (1.3%) patients treated with radiation therapy alone. Other moderate or severe nonfatal sequelae were noted in 30% of the patients treated with preoperative irradiation and surgery, in 53% treated with postoperative irradiation, and in 19% receiving radiation therapy alone. CONCLUSION: Primary tumor and neck node stage are the only significant prognostic factors influencing locoregional tumor control and disease-free survival. Treatment modality had no significant impact on outcome. Radiation therapy remains the treatment of choice for patients with stage T1-T2 carcinoma of the tonsillar fossa. In patients with T3-T4 tumors and good general condition, combination surgery and postoperative irradiation offers better tumor control than single-modality and preoperative irradiation procedures, but with greater morbidity.     

Interaction of Listeria monocytogenes with human brain microvascular endothelial cells: InlB-dependent invasion, long-term intracellular growth, and spread from macrophages to endothelial cells

Invasion of endothelial tissues may be crucial in a Listeria monocytogenes infection leading to meningitis and/or encephalitis. Internalization of L. monocytogenes into endothelial cells has been previously demonstrated by using human umbilical vein endothelial cells as a model system. However, during the crossing of the blood-brain barrier, L. monocytogenes most likely encounters brain microvascular endothelial cells which are strikingly different from macrovascular or umbilical vein endothelial cells. In the present study human brain microvascular endothelial cells (HBMEC) were used to study the interaction of L. monocytogenes with endothelial cells, which closely resemble native microvascular endothelial cells of the brain. We show that L. monocytogenes invades HBMEC in an InlB-dependent and wortmannin-insensitive manner. Once within the HBMEC, L. monocytogenes replicates efficiently over a period of at least 18 h, moves intracellularly by inducing actin tail formation, and spreads from cell to cell. Using a green fluorescent protein-expressing L. monocytogenes strain, we present direct evidence that HBMEC are highly resistant to damage by intracellularly growing L. monocytogenes. Infection of HBMEC with L. monocytogenes results in foci of heavily infected, but largely undamaged endothelial cells. Heterologous plaque assays with L. monocytogenes-infected P388D1 macrophages as vectors demonstrate efficient spreading of L. monocytogenes into HBMEC, fibroblasts, hepatocytes, and epithelial cells, and this phenomenon is independent of the inlC gene product.