Two outbreaks of typhoid fever related to the war in Bosnia and Herzegovina

Two outbreaks of typhoid fever caused by Salmonella typhi of the same phagotype (A, biotype II) and antibiotic susceptibility are reported. Both occurred during the war in Bosnia and Herzegovina. The first outbreak appeared among the refugees from the town of Jajce. The second outbreak appeared among the inhabitants in the village of Vidosi near Livno. This report describes main clinical, epidemioloigcal and laboratory findings for 22 patients treated in Split University Hospital, Croatia, in the period November 1992–January 1993. Possible epidemiological connections between those two outbreaks are discussed.     

Online learning applied to a course on rational therapeutics: an international comparison between final year students of two medical schools

Introduction

Poor prescribing is probably the most common cause of preventable medication errors and many of these events involve junior doctors. In 2009, an electronic problem-based therapeutics course developed at the University of Michigan Medical School (UMMS) was translated and adapted for use at the University of Zagreb Medical School (UZMS).

Methods

After students from both schools took the course in 2010, we compared their responses with an online questionnaire addressing the course quality and its effectiveness.

Results

There were no statistically significant differences in the overall average grades awarded for the course (UZMS 4.11 ± 0.86 vs. UMMS 3.96 ± 0.93; 95% CI mean difference (MD) – 0.36, 0.07; P = 0.175) with both student groups expressing high satisfaction rates with its quality, accessibility and overall design. UZMS students reported spending less time working through the course than their American colleagues (2.14 ± 1.01 vs. 2.89 ± 1.02 on a five point Likert scale; 95% CI MD 0.51, 0.99; P < 0.05). Furthermore, Croatian students indicated greater difficulty with course materials (3.54 ± 0.59 vs. 3.25 ± 0.59; 95% CI MD – 0.42, – 0.15; P < 0,05) and weekly multiple choice questions (3.83 ± 0.62 vs. 3.4 ± 0.61; 95% CI MD – 0.58, – 0.29; P < 0,05) compared with the UMMS students.

Conclusion

It is possible to adapt and translate successfully whole online teaching resources and implement them internationally in different countries and health care systems, achieving similar, high student satisfaction rates while decreasing administrative and cost burdens. Web based learning may have great potential to offer a cost effective and safe environment in which prescribing skills can be improved.     

The measurement of sodium and potassium intake

Single- vs multiple-day food records were compared for estimates of intake for sodium, potassium, and calories; and the correspondence was assessed between sodium and potassium intake and 24-h urinary excretion. Fifty-five middle-aged adults, participating in a prerandomization assessment for a nutritional/behavioral intervention program on blood pressure completed a six-day food record and a 24-h urine collection. The group average for sodium, potassium, and calories obtained from one-day food records proved to be as good an estimate of the six-day average as did values from multiple day records. Similarly the one-day food record proved a good estimate of the mean 24-h urinary values for sodium and potassium. If properly collected and analyzed, a one-day food record is a good estimate of a population's intake of sodium and potassium while multiple days of recording are necessary to characterize individual intake.     

Histamine release, an undesired effect of thrombin inhibitors with basic character, is mediated through direct activation of G(i) proteins

The common structural feature of LK direct thrombin inhibitors is a strong basic group attached to the azaphenylalanine scaffold, which is important for the appropriate interaction at the thrombin active site. Our previous results have shown that this basic group could be responsible for a reduction of tracheal air flow and a fall of mean arterial pressure in anaesthetized rats, an undesired effect of direct thrombin inhibitors which correlated with their ability to release histamine from mast cells. In the present study, we investigated the mechanism of LK direct thrombin inhibitors-induced histamine release from rat peritoneal mast cells. We demonstrated that thrombin inhibitors with basic character (LK-732, LK-639 and LK-6063) provoked release of histamine from mast cells, while less basic analogs (LK-658, LK-633 and LK-6062) had no effect. Histamine released by LK-732 and LK-639 was suppressed by removal of sialic acid residues by neuraminidase and by pertussis toxin, an inhibitor of G(i) protein activity. Additional demonstration that G proteins are the targets of LK-732 and LK-639 was provided by the increase of GTPgammaS binding rate to G proteins in rat brain cortical membranes. Our results indicate that basic direct thrombin inhibitors LK-732 and LK-639 provoke release of histamine from mast cells by direct activation of G(i) proteins through the similar biochemical pathway as basic secretagogues.     

Research staff turnover and participant adherence in the Women's Health Initiative

Maintaining participant adherence is a prerequisite for successful completion of randomized controlled trials requiring long-term follow-up. While patient characteristics influencing adherence are well studied, the influence of contact with clinical staff on this process has received almost no attention. To address this issue the authors evaluated the association of turnover in key clinical research staff with measures of participant adherence to protocol requirements at 40 clinical centers participating in the Women's Health Initiative (WHI), a large multicenter study. Key staff turnover in positions with potential influence on maintaining participant adherence in the Dietary Modification Clinical Trial (DM-CT) and the two Menopausal Hormone Therapy Clinical Trials (HT-CT) of the WHI was determined at each clinical center. Three prospectively established measures of participant adherence for the DM-CT and HT-CT were related to key staff turnover at each clinical center by staff category. More frequent turnover of the clinic practitioner, clinic manager, and principal investigator positions was significantly (p<0.05) associated with lower participant adherence in the HT-CT but was not associated with DM-CT participant adherence. More frequent turnover of the lead nutritionist was not associated with HT-CT participant adherence but was significantly (p<0.05) associated with one measure of decreased DM-CT participant adherence, as would be expected since the lead nutritionist did not typically see the HT-CT participants. These significant and plausible associations suggest that providing consistent contact with key staff in randomized, controlled clinical trials may facilitate long-term participant adherence. Further prospective study exploring process evaluation of the provider side of controlled trial conduct is indicated.     

Tick-borne encephalitis – lipid peroxidation and its consequences

Background: The purpose of this study was to assess the processes of lipid peroxidation with prostaglandin derivatives and reactive aldehydes being its major indicators in cerebrospinal fluid (CSF), plasma and urine of patients with tick-borne encephalitis (TBE). Materials and methods: This study included 60 patients with TBE and 56 healthy subjects. Lipid peroxidation was estimated by the measurement of 4-hydroxynonenal (4-HNE), 4-hydroxyhexenal (4-HHE), malondialdehyde (MDA), acrolein, crotonaldehyde, and 4-oxononenal (4-ONE), determined by GC-MS, F₂-isoprostanes and neuroprostanes (NPs) level determined by LC-MS. The level of 4-HNE-protein adducts was determined by ELISA. Phospholipase A₂ (PLA₂), platelet-activating factor acetylhydrolase (PAF-AH) and glutathione peroxidase (GSH-Px) activities and vitamin E level were determined spectrophotometrically and by HPLC, respectively. In parallel, the plasma levels of phospholipid acids such as arachidonic acid (AA), linoleic acid (LA) and docosahexaenoic acid (DHA) were monitored. Results: A significant decrease in AA, LA, DHA level and GSH-Px activity (by about 20, 69, 11 and 18%, respectively) was observed. The consequence of enhanced phospholipid peroxidation was almost 7 times higher plasma level of F₂-isoprostanes and 3-fold increase in NPs level in CSF of TBE patients. Additionally a 3.5-fold increase in the CSF level of MDA, 5-fold increase in the plasma level of 4-HNE and urine level of 4-HHE in TBE patients was observed. Decreased plasma activity of PLA₂ with an increase in the PAF-AH activity was observed. Conclusion: Lipid peroxidation occurring during TBE development indicates its relevance in pathophysiology of this disease. Moreover lipid peroxidation products might be useful for the diagnosis of TBE.     

Dramatic increase in naive T cell turnover is linked to loss of naive T cells from old primates

The loss of naïve T cells is a hallmark of immune aging. Although thymic involution is a primary driver of this naïve T cell loss, less is known about the contribution of other mechanisms to the depletion of naïve T cells in aging primates. We examined the role of homeostatic cycling and proliferative expansion in different T cell subsets of aging rhesus macaques (RM). BrdU incorporation and the expression of the G₁-M marker Ki-67 were elevated in peripheral naïve CD4 and even more markedly in the naïve CD8 T cells of old, but not young adult, RM. Proliferating naïve cells did not accumulate in old animals. Rather, the relative size of the naïve CD8 T cell compartment correlated inversely to its proliferation rate. Likewise, T cell receptor diversity decreased in individuals with elevated naïve CD8 T cell proliferation. This apparent contradiction was explained by a significant increase in turnover concomitant with the naïve pool loss. The turnover increased exponentially when the naïve CD8 T cell pool decreased below 4% of total blood CD8 cells. These results link the shrinking naïve T cell pool with a dramatic increase in homeostatic turnover, which has the potential to exacerbate the progressive exhaustion of the naïve pool and constrict the T cell repertoire. Thus, homeostatic T cell proliferation exhibits temporal antagonistic pleiotropy, being beneficial to T cell maintenance in adulthood but detrimental to the long-term T cell maintenance in aging individuals.     

Combination of radiotherapy with EGFR antagonists for head and neck carcinoma

The introduction of biologically sound radiation fractionation regimens and combinations of radiotherapy with chemotherapy have gradually improved both the survival of patients with locally advanced head and neck squamous cell carcinoma (HNSCC) and the prospect of organ preservation. Long-term follow-up, however, has shown that some of the radiation–chemotherapy combinations are associated with increased late toxicity. This observation, in conjunction with advances in tumor biology, has led to the launch of investigations into molecular markers and targets for therapeutic interventions. Research on the epidermal growth factor receptor (EGFR)-mediated signaling pathway has enriched our understanding of the biology of HNSCC, in terms of carcinogenesis and cellular processes governing tumor response to therapy. The finding that the addition of an antibody-based inhibitor of the EGFR pathway to radiotherapy significantly improves locoregional control and overall survival rates in patients with locally advanced HNSCC, without increasing radiation-induced toxicity, has resulted in the growing acceptance of such combined regimens as a frontline therapy option for locally advanced HNSCC. Because such therapy has benefited only an additional 10%-15% of patients, studies are being undertaken to identify markers and mechanisms of resistance to EGFR antagonists that are essential for the further refinement of therapy. Overall, preclinical and clinical studies on EGFR have validated the concept that selective tumor radiation sensitization can be achieved by modulating a specific perturbed signaling pathway, and these studies have increased the enthusiasm for developing and investigating other novel agents targeting other cellular processes. Dr. L. Milas has received research funding from Imclone Systems Inc. and Sanofi-Aventis. Dr. K.K. Ang has served on Advisory Boards of AstraZeneca, Bristol-Myers Squibb, Imclone Systems Inc., and Sanofi-Aventis.