Einfluss der genetischen Herkunft auf die Mast- und Schlachtleistung, die Fleisch- und Fettqualität sowie das Fettsäurenmuster der Phospholipide von Mastschweinen

Abstract. Title of the paper: Influence of different genetic origins on fattening and carcass performance, on quality of meet and fat as well as fatty acid pattern of phospholipids from pigs For the purpose of comparing the fattening and carcass performance as well as the meat and fat quality of pigs the different genetic origins German Landrace (DL), Piétrain (Pi) and Duroc (Du) as well as the crossbreeds DL×Du, Pi×(DL×Du) and (Pi×Ha)×(DL×Du) were fattened from 30 to 105 kg liveweight. The pigs of three-breed cross indicate a higher fattening performance. The Piétrains fall of at fattening performance, however they shows highest lean content (MFA). The meat condition marks Piétrains as PSE suspected connected with the lowest content of intramuscular fat (IMF). Duroc pigs are ahead in every meat quality criteria. A exceptional position hold the three-breed cross pigs with strong marbling, however a insufficient conductivity. Fatty acid composition turn out to be unfriendly in Piétrains and cross breeding pigs with high MFA in due to high contents of polyenoic. Contrary to it Durocs achieve with lowest MFA the clearest marbling and with highest content on saturated fatty acids the best fat quality over all. The straight breed shows at phospholipids the highest content of polyunsaturated fatty acids. For economical valuation of the genetic origins three index models were shown. By restriction on feed consumption and MFA, the Piétrains and the crossbreeds are clear ahead. The rank changes after adding the parameters of meat quality (IMF, LF24) for the benefit of German Landrace and Duroc, bond up with considerable devaluation of Piétrains. The additional consideration of fat quality (polyenoic) indicates no further variation in the gradation of the genetic origins.

A validated PCR-based method to detect Listeria monocytogenes using raw milk as a food model--towards an international standard

A PCR assay with an internal amplification control was developed for Listeria monocytogenes. The assay has a 99% detection probability of seven cells per reaction. When tested against 38 L. monocytogenes strains and 52 nontarget strains, the PCR assay was 100% inclusive (positive signal from target) and 100% exclusive (no positive signal from nontarget). The assay was then evaluated in a collaborative trial involving 12 European laboratories, where it was tested against an additional 14 target and 14 nontarget strains. In that trial, the inclusivity was 100% and the exclusivity was 99.4%, and both the accordance (repeatability) and the concordance (reproducibility) were 99.4%. The assay was incorporated within a method for the detection of L. monocytogenes in raw milk, which involves 24 h of enrichment in half-Fraser broth followed by 16 h of enrichment in a medium that can be added directly into the PCR. The performance characteristics of the PCR-based method were evaluated in a collaborative trial involving 13 European laboratories. In that trial, a specificity value (percentage of correct identification of blank samples) of 81.8% was obtained; the accordance was 87.9%, and the concordance was 68.1%. The sensitivity (correct identification of milk samples inoculated with 20 to 200 L. monocytogenes cells per 25 ml) was 89.4%, the accordance was 81.2%, and the concordance was 80.7%. This method provides a basis for the application of routine PCR-based analysis to dairy products and other foodstuffs and should be appropriate for international standardization.

Pharmacokinetics and pharmacodynamic effects of amiodarone in plasma of ponies after single intravenous administration

Atrial fibrillation is a well-known heart disease in horses. The common therapy consists of administration of quinidine. More potent antiarrhythmic drugs have become available for human therapy and the use of these as alternatives to quinidine for equine antiarrhythmic therapy is a matter of interest. Amiodarone (AMD) is used in human medicine for treatment of many arrhythmias, including atrial fibrillation. Its disposition in horses has not yet been investigated. The purpose of this study was to measure the effect of single intravenous doses of amiodarone (5 and 7 mg/kg) on the surface electrocardiogram (ECG) of healthy minishetland ponies during the first 2 days after drug administration and to calculate pharmacokinetic parameters with a physiologically based pharmacokinetic model (PBPK) using amiodarone and desethylamiodarone (DAMD) plasma levels that were determined by high-performance liquid chromatography (HPLC). As expected for a K(+)-channel-blocker, the main effect on the measured ECG could be seen on the ventricular complex, as the QT interval and the T wave showed statistically significant alterations. The doses investigated were well tolerated clinically. Results from the pharmacokinetic model were found to compare well with literature data of rats, dogs, and humans. It showed a rapid distribution in the tissue, beginning with the rapidly perfused tissue, like the heart, followed by slowly perfused tissues, and finally an accumulation in fat. The half-life for total elimination was calculated to be 16.3 days with 99% eliminated by 97 days. The model predicts that approximately 96% of amiodarone is eliminated as desethylamiodarone in urine, 2% eliminated as desethylamiodarone in bile, and 2% as other metabolites.

[Massive unilateral hydrothorax as clinical manifestation of decompensated liver cirrhosis without ascites]

The case of a 56-year-old man with a massive unilateral rightsided pleural effusion is described. The origin of the pleural effusion is a decompensated liver cirrhosis without ascites. The pathogenetic mechanisms and treatment are discussed.

Blood viscosity and platelet function in patients with obstructive sleep apnea syndrome treated with nasal continuous positive airway pressure

Patients with obstructive sleep apnea syndrome (OSA) have a high incidence of cardiovascular events. We measured whole blood viscosity at high (94.5 s(-1)) and low (0.1 s(-1)) shear rate, hematocrit, fibrinogen, and platelet hemostatic function (PTA-100) at 7-8 p.m. and 7-8 a.m. in 8 controls and 13 patients, once with the established nasal continuous positive airway pressure (NCPAP) treatment and once without. OSA patients had a higher plasma viscosity (1.37+/-0.11 vs. 1.19+/-0.11 mPa.s in the evening, p<0.05) and fibrinogen (2.61+/-0.49 vs. 2.11+/-0.29 g/l, p<0.05) than controls, without diurnal difference, and similar values with or without NCPAP. Whole blood viscosity and hematocrit were similar in controls and patients before and after a night with or without NCPAP. Platelet activity was significantly higher in the morning than in the evening in controls and patients with or without NCPAP. We conclude that blood viscosity and platelet activity are similar in controls and patients with OSA on a long-term treatment with NCPAP, which is not worsened by a single night without NCPAP. The increase of plasma viscosity and fibrinogen in OSA patients as well as the general increase of platelet aggregation in the morning may contribute to the increased incidence of cardiovascular events.

[Unilateral pulmonary edema in a dialysis patient with massive fluid overload and mitral valve insufficiency]

A pulmonary edema is not a rare complication in patients with chronic renal failure. Arterial hypertension and fluid overload play a pathogenetically important role. The diagnosis of an unilateral pulmonary edema is often difficult. The following arguments favour the diagnosis: rapid clinical amelioration and disappearance of the alveolar opacities after diuretic treatment alone within 24-72 hours. We describe the case of a 37-year-old patient on dialysis treatment who showed a pulmonary edema of the right lung, predominantly in the upper lobe. This edema was due to fluid overload and mitral insufficiency. After diuretic treatment alone the patient rapidly recovered and the lung infiltrates on the chest X-ray disappeared within a few days.

Impaired vasodilator responses to atrial natriuretic peptide in essential hypertension

BACKGROUND

Atrial natriuretic peptide (ANP) has vasodilating and diuretic/natriuretic properties, both of which contribute to lower blood pressure. These effects are mediated by binding of ANP to a cell-surface receptor [type A guanylyl cyclase (GC-A)]. It has been demonstrated by studies in monogenetic mouse models that the ANP/GC-A system participates in the maintenance of blood pressure homeostasis.

METHODS

In male patients with essential hypertension (EH; n = 36) as the only cardiovascular risk factor and normotensive controls (n = 12), blood flow was measured in the forearm circulation in response to i.a. infusion of synthetic human ANP, acetylcholine, orciprenaline, and sodium nitroprusside by strain-gauge venous plethysmography. In blood samples, cyclic guanosine'5-monophosphate (cGMP) and ANP concentrations were measured at resting conditions and during exogenous ANP infusion. In 200 patients with EH, genomic DNA was screened for an inhibitory deletion mutation of the GC-A gene, which has been recently linked to EH in a Japanese cohort.

RESULTS

The vasodilatations in response to ANP and acetylcholine were impaired in the forearm circulation of patients with EH, whereas the responses to orciprenaline and nitroprusside were preserved. Plasma ANP and cGMP concentrations were increased in the patients with EH both at resting conditions and during ANP infusion; the resting plasma cGMP levels correlated significantly with the plasma ANP levels (r = 0.68). A specific deletion mutation of the GC-A gene did not account for the diminished relaxant effects of ANP in our study population.

CONCLUSIONS

The vascular ANP/GC-A pathway is altered in patients with EH, in addition to the known defects on the nitric oxide/cGMP pathway. Attenuation of the vasodilative responses to ANP suggests impaired receptor or postreceptor responsiveness of GC-A. It is possible that this dysfunction participates in the pathomechanism of EH.

[Brain irradiation and phenytoin: a dangerous liaison?]

Three patients are presented, who developed a severe skin reaction after brain-irradiation and concomitant phenytoin treatment. A fourth patient from the databAse of the Swiss Drug Monitoring Center, showed a Stevens-Johnson-Syndrome after a severe electric shock and phenytoin treatment. Possible pathogenic mechanisms of these life-threatening complications and possible alternatives to the phenytoin treatment in irradiated patients are discussed.

Identification and characterisation of regions in the cellular protein LaXp180 and the Listeria monocytogenes surface protein ActA necessary for the interaction of the two proteins

The Listeria monocytogenes surface protein ActA is an important virulence factor that plays an essential role in intracellular movement of Listeria cells by inducing actin polymerisation. The ActA protein is known to interact with several mammalian proteins including the phosphoprotein VASP, actin and the Arp2/3 complex. In a search for additional ActA-binding proteins we recently employed the yeast two-hybrid system to search for proteins that interact with ActA, and identified, among others, the mammalian protein LaXp180 as a binding partner. In the present study the interaction of the two proteins was investigated in more detail. A number of variants were tested in the yeast two-hybrid system for their ability to interact. On the basis of these assays, the 14 C-terminal amino acids of LaXp180 were identified as being necessary for the interaction with ActA. The proline-rich repeat (PRR) region of ActA was found to be necessary for the interaction with LaXp180, but upstream or downstream sequences are also required to enhance the specificity of the interaction. The second and third repeats in ActA are especially important, and the minimal sequence of ActA capable of interacting with LaXp180 was a proline- and glutamate-rich stretch of PRR3 fused to part of the N-terminal sequence of ActA. Further analysis using site-specific mutations located in either the C-terminal region of LaXp180 or the proline-rich motif of PRR3 of ActA showed that three positively charged amino acids in LaXp180 and two negatively charged amino acids in ActA are critical for the interaction of the two proteins.

Progressive cardiac hypertrophy and dysfunction in atrial natriuretic peptide receptor (GC-A) deficient mice

OBJECTIVE

To investigate how permanent inhibition of guanylyl cyclase A receptor (GC-A) affects cardiac function.

METHODS

Hearts of GC-A-/- and corresponding wild type mice (GC-A+/+) were characterised by histological, western blotting, and northern blotting analyses. Cardiac function was evaluated in isolated, working heart preparations.

RESULTS

At 4 months of age, GC-A-/- mice had global cardiac hypertrophy (about a 40% increase in cardiac weight) without interstitial fibrosis. Examination of heart function found a significant delay in the time of relaxation; all other parameters of cardiac contractility were similar to those in wild type mice. At 12 months, the hypertrophic changes were much more severe (about a 61% increase in cardiac weight), together with a shift in cardiac gene expression (enhanced concentrations of atrial natriuretic peptide (3.8-fold), B type natriuretic peptide (2-fold), beta myosin heavy chain (1.6-fold) and alpha skeletal actin (1.7-fold) mRNA), increased expression of cytoskeletal tubulin and desmin (by 29.6% and 25.6%, respectively), and pronounced interstitial fibrosis. These changes were associated with significantly impaired cardiac contractility (+dP/dt decreased by about 10%) and relaxation (-dP/dt decreased by 21%), as well as depressed contractile responses to pressure load (all p < 0.05).

CONCLUSIONS

Chronic hypertension in GC-A-/- mice is associated with progressive cardiac changes--namely, initially compensated cardiomyocyte hypertrophy, which is complicated by interstitial fibrosis and impaired cardiac contractility at later stages.

[Ambulance transport of patients with respiratory problems: a prospective observational study]

The aim of this study was to prospectively compile and analyze all emergency transports of patients with respiratory problems. The main target variables were frequency of the different reasons for transport and treatments administered during the emergency event. Special emphasis was placed on the use of inhalation therapy. The data of all patients who, in 2000, were transported by the "Realü" emergency medical service of the Chur Rhine Valley (a community with a population of approximately 100,000) due to respiratory problems were prospectively compiled according to predefined criteria. The emergency records and the medical release reports were evaluated. A total of 137 patients were prospectively included for the year 2000, corresponding to 8% of all patients transported by "Realü" (out of a total of 1675 patients). The average age was 66 years (2-98 years). Around one-fifth of the transports involved patients with exacerbations of chronic obstructive pulmonary disease (COPD), pulmonary embolisms, pulmonary infections or cardiac dyspnea. Six patients (5%) were transported by ambulance because of bronchial asthma. Inhalation therapy was administered in only 41% of the cases with obstructive pulmonary disease in which it would have been indicated. In conclusion, our evidence shows that bronchial asthma is the primary diagnosis in only 6% of the patients requiring emergency transport due to respiratory symptoms. In these emergency situations, antiobstructive inhalation therapy was given to a mere 41% of the patients suffering exacerbations of COPD or bronchial asthma. More frequent use of such a simple and effective treatment should be encouraged.

[Suspected neurological side-effects of tick-borne meningoencephalitis vaccination: experiences of the Swiss Adverse Drug Reaction Reporting Center]

The number of patients affected by tick-born encephalitis (TBE) in Switzerland has increased in the last years and an extension of the endemic foci of TBE has been observed. Therefore, active immunization by TBE vaccination has become more important. The possible adverse vaccine reactions have to be known as exactly as possible. The Swiss Drug Monitoring Center SANZ received from 1987 until June 2000 33 spontaneous cases reporting on 39 neurological adverse reactions in a close temporal relationship with a TBE vaccination and a suspected causal relationship. The following adverse reactions were reported most frequently: headache in 36%, neuropathy in 18% and meningeal irritation in 13%. Twelve out of 33 patients were hospitalized due to the adverse reaction. All neurological reactions were reversible. The spontaneous reporting scheme of the SANZ does not allow to calculate the incidence of neurological reactions after TBE vaccination. In general, adverse neurological reactions after TBE vaccination seem to be rare. According to the experiences of SANZ all reported neurological reactions were reversible.

Comparative genomics of Listeria species

Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.

Drug-induced bronchospasm: analysis of 187 spontaneously reported cases

BACKGROUND

The Swiss Drug Monitoring Center (SANZ) uses a systematic approach to the collection of spontaneously reported individual cases on suspected adverse drug reactions (ADRs). Spontaneous reporting schemes are designed to detect new, rare and unexpected ADRs and to act as an early warning system but there is a tendency to overreport severe reactions.

OBJECTIVES

The aim of the study was to determine drug-induced episodes of bronchospasm, their seriousness and predisposing risk factors. An ADR is classified as serious if the reaction results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability or incapacity.

RESULTS

From 1986 to 1995 SANZ received 8,191 case reports of suspected ADRs. In 187 cases (2%) bronchospasm was reported. In 55% of these cases the reaction was regarded as serious. Analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs) were reported most frequently and were involved in 24% of the cases of which 64.5% were classified as serious. In three cases a lethal outcome was reported after intravenous administration of metamizol. Anti-infectious agents were implicated in 18% (52% serious), cardiovascular drugs in 11% (50% serious), drug formulation agents in 9% (41% serious), vaccines and immunoglobulins in 5.5% (50% serious), and plasma volume expanders in 5.5% (80% serious). Other drug groups were involved in 27% of the cases. About 50% of patients experiencing bronchospasm after NSAIDs, pharmaceutical formulation agents, vaccines and immunoglobulins had predisposing risk factors such as asthma, atopy or drug allergy. In other drug groups a predisposing factor was identified in 27% or less.

CONCLUSION

Drug-induced bronchospasm is frequently reported with NSAIDs, anti-infective agents, cardiovascular drugs and excipients with a high proportion of serious reactions.

[Pseudotumor cerebri in minocyline treatment]

Pseudotumor cerebri or benign intracranial hypertension is a syndrome of raised intracranial pressure without obvious explanation. Most patients are obese women at childbearing age. Symptoms and signs usually include headache, nausea, vomiting, edema of the papilla, visual obscurations and rarely palsy of the nervus abducens. The prognosis is generally good, but progressive visual loss and eventual blindness are major risks. We report the case of a 21-year-old non-obese young woman who developed pseudotumor cerebri while taking minocycline for acne therapy. Identical symptoms occurred upon inadvert rechallenge with minocycline for the second time.

Accuracy of emergency department bedside ultrasonography

OBJECTIVES

To determine which focused ultrasound examinations can be interpreted accurately by emergency physicians who have limited training and experience. To determine whether image quality and/or the operator's level of confidence in the findings correlates with accurate scan interpretation.

METHODS

A prospective sample of consenting adult emergency department patients with the conditions was selected for study. Scans were performed by emergency physicians who had attended a 3-day focused ultrasound examinations instruction course. All scans were videotaped and subsequently reviewed by a radiologist. Accuracy was determined by comparing the emergency physicians scan interpretation with preselected gold standards. Chi-squared tests were employed to determine if the individual performing the scan, the type of scan, patient's body habitus, image quality and/or operator confidence were reliable predictors of accuracy.

RESULTS

Between September 1997 and January 1999, 221 scans were studied. Accuracy varied widely depending on the type of scan performed: aortic scans were 100% accurate whereas renal scans had 68% accuracy. On bivariate analyses, there was little variation in the various operators' levels of proficiency and accuracy of interpretation was not associated with patient body habitus, image quality or operator confidence.

CONCLUSIONS

Neophytes can accurately perform and interpret aortic scans; additional training and/or experience appear to be necessary to achieve proficiency in conducting most of the other scans studied. Inexperienced operators are unable to discern whether their scan interpretations will prove accurate.

High salt intake increases uroguanylin expression in mouse kidney

The intestinal peptides, guanylin and uroguanylin, may have an important role in the endocrine control of renal function. Both peptides and their receptor, guanylyl cyclase C (GC-C), are also expressed within the kidney, suggesting that they may act locally in an autocrine/paracrine fashion. However, their physiological regulation within the kidney has not been studied. To begin to address this issue, we evaluated the distribution of uroguanylin and guanylin messenger RNA (mRNA) in the mouse nephron and the regulation of renal expression by changes in dietary salt/water intake. Expression was determined in 1) wild-type mice, 2) two strains of receptor-guanylyl cyclase-deficient mice (ANP-receptor-deficient, GC-A-/-, and GC-C-deficient mice); and 3) cultured renal epithelial (M-1) cells, by RT-PCR, Northern blotting and immunocytochemistry. Renal uroguanylin messenger RNA expression was higher than guanylin and had a different distribution pattern, with highest levels in the proximal tubules, whereas guanylin was mainly expressed in the collecting ducts. Uroguanylin expression was significantly lower in GC-C-/- mice than in GC-A-/- and wild-types, suggesting that absence of a receptor was able to down-regulate ligand expression. Salt-loading (1% NaCl in drinking water) increased uroguanylin-mRNA expression by >1.8-fold but had no effect on guanylin expression. Uroguanylin but not guanylin transcripts were detected in M-1 cells and increased in response to hypertonic media (+NaCl or mannitol). Our results indicate that high-salt intake increases uroguanylin but not guanylin expression in the mouse kidney. The synthesis of these peptides by tubular epithelium may contribute to the local control of renal function and its adaptation to dietary salt.

The anatomy of a shark attack: a case report and review of the literature

Shark attacks are rare but are associated with a high morbidity and significant mortality. We report the case of a patient's survival from a shark attack and their subsequent emergency medical and surgical management. Using data from the International Shark Attack File, we review the worldwide distribution and incidence of shark attack. A review of the world literature examines the features which make shark attacks unique pathological processes. We offer suggestions for strategies of management of shark attack, and techniques for avoiding adverse outcomes in human encounters with these endangered creatures.

[Clinical value of native and contrast enhanced MRI in staging prostatic carcinoma before planned radical prostatectomy]

PURPOSE

To assess the clinical value of MRI with and without contrast agent in the staging of prostatic carcinoma. Relevance for surgical management.

METHODS

60 patients with carcinoma proven by biopsy or suspected prostatic carcinoma were evaluated with MRI. The examinations were performed in a 1.5 T (Philips ACS-NT Gyroscan) imager with multiplanar orientations before and after intravenous application of 0.1 mmol/kg/bw Gadodiamide (Omniscan-Nycomed/Amersham). The gold standard was histology after radical prostatectomy and in case of non-operability the consensual final staging.

RESULTS

Compared to histology MRI revealed a sensitivity of 75% and a specificity of 82% in the differentiation of locally advanced carcinoma (T 3/4). Including the non-surgical cases MRI showed a sensitivity of 82.5% and a specificity of 86%. Interindividual analysis showed no difference in diagnostic accuracy between the non-enhanced and the contrast-enhanced techniques. In 23% of cases (n = 14) MRI induced changes in patient management.

CONCLUSIONS

MRI is an accurate procedure in the local staging of prostatic carcinoma. In combination with clinical findings, PSA, and grading scores MRI has a significant influence on treatment selection. Contrast agent administration does not seem to increase the diagnostic accuracy significantly.

Listeria pathogenesis and molecular virulence determinants

The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal individuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research.

Immunoisolation of TCR signaling complexes from Jurkat T leukemic cells

The formation of multimolecular assemblies of signaling molecules at the plasma membrane is key to triggering signaling cascades following activation of transmembrane receptors at the plasma membrane. We have developed a method to immunoisolate activated T cell receptors (TCRs) and associated signaling molecules in plasma membrane subdomains from Jurkat T leukemic cells. The immunoisolation procedure for the signaling complexes uses magnetic beads, which are coupled to TCR-activating antibodies. Following mechanical cellular disruption using nitrogen cavitation, conjugates of these beads with Jurkat cells are formed and isolated. TCR-signaling complexes within plasma membrane fragments associate with the antibody-coupled beads and are retrieved along with the beads using a magnet. We found that the immunoisolated plasma membrane fragments are highly enriched for activated TCRs and associated signaling proteins. This isolation procedure allows a detailed and precise biochemical analysis of the assembly of signaling proteins in plasma membrane subdomains.

Gamma-hydroxybutyrate overdose and physostigmine: teaching new tricks to an old drug?

Gamma-hydroxybutyrate was introduced as an anesthetic agent in the 1960s and is still used in some countries, despite recognized disadvantages. More recently, it has emerged as a popular recreational drug. We report 3 cases of gamma-hydroxybutyrate overdose, the effects of which were reversed by the administration of low-dose intravenous physostigmine. The origins of this regimen and the case for physostigmine as a potential antidote are described.

[Reactivation of herpes virus infections by vaccination: evidence or coincidence?]

Varicella zoster and herpes simplex viruses cause latent infections by persisting in human cells. Reactivation has been associated with increasing age, immunosuppression, cancer, stress, fever, exposure to ultraviolet light, and tissue damage. Based on three cases reported to the Swiss Drug Monitoring Centre SANZ, we postulated previously that vaccinations may trigger reactivation of herpes virus infections due to vaccine-induced immunomodulation. In the meantime, 10 new cases of reactivated herpes virus infections soon after vaccinations have been reported. They involved 5 women and 5 men with an age range between 16 and 60. In only one case had a trauma preceded, otherwise healthy subjects with no known relevant comorbidity were vaccinated. The clustering of reports after publication points to a previous underreporting of similar cases. This may be explained by the fact that both vaccinations and reactivations of herpes virus infections are frequent, and a causal link is not suspected. However, these new cases do not prove causality, and extensive epidemiological or experimental studies are needed to elucidate the possible link between vaccination and reactivation of herpes virus infections.

Evaluation of local and systemic immune responses induced by intramuscular injection of a Mycoplasma hyopneumoniae bacterin to pigs

OBJECTIVE

To evaluate immune responses induced by administration of Mycoplasma hyopneumoniae bacterin to pigs. Animals-60 healthy 7- to 10-day-old cross-bred boars.

PROCEDURE

Pigs were assigned to 1 of 4 pig groups (15 pigs/group): vaccinated, challenged; vaccinated, nonchallenged; nonvaccinated, challenged; nonvaccinated, nonchallenged. Vaccinated pigs received IM injections of a mycoplasma bacterin on days 0 and 14, whereas nonvaccinated pigs received saline (0.9% NaCl) solution. Pigs in the challenged groups were inoculated intratracheally with M hyopneumoniae on day 42. Pigs were euthanatized and necropsied 41, 44, 48, and 70 days after the first vaccination, and proportion of lung surface with pneumonic lesions was determined. Percentage of lymphocyte subpopulations and number of interferon-gamma (IFN-gamma) secreting lymphocytes in blood and tissues, cytokine and antibody concentrations in bronchoalveolar lavage (BAL) fluid, and serum antibody concentrations were determined.

RESULTS

Vaccination against and infection with M hyopneumoniae induced a local mucosal immune response in the respiratory tract of pigs. Proportion of lung surface with pneumonic lesions in vaccinated challenged pigs was reduced on day 70, compared with nonvaccinated challenged pigs. Vaccination stimulated the production of M hyopneumoniae-specific IFN-gamma secreting blood lymphocytes. Tumor necrosis factor-alpha concentration in BAL fluid on day 70 was increased in nonvaccinated challenged pigs, compared with vaccinated challenged pigs.

CONCLUSIONS AND CLINICAL RELEVANCE

Vaccination against M hyopneumoniae induced local, mucosal, humoral, and cellular immune responses. Moreover, vaccination reduced the severity of lung lesions in challenged pigs, suggesting that mucosal antibodies, mediation of the inflammatory response, and cell-mediated immune responses are important for control of mycoplasmal pneumonia in pigs.

Selective accumulation of raft-associated membrane protein LAT in T cell receptor signaling assemblies

Activation of T cell antigen receptor (TCR) induces tyrosine phosphorylations that mediate the assembly of signaling protein complexes. Moreover, cholesterol-sphingolipid raft membrane domains have been implicated to play a role in TCR signal transduction. Here, we studied the assembly of TCR with signal transduction proteins and raft markers in plasma membrane subdomains of Jurkat T leukemic cells. We employed a novel method to immunoisolate plasma membrane subfragments that were highly concentrated in activated TCR-CD3 complexes and associated signaling proteins. We found that the raft transmembrane protein linker for activation of T cells (LAT), but not a palmitoylation-deficient non-raft LAT mutant, strongly accumulated in TCR-enriched immunoisolates in a tyrosine phosphorylation-dependent manner. In contrast, other raft-associated molecules, including protein tyrosine kinases Lck and Fyn, GM1, and cholesterol, were not highly concentrated in TCR-enriched plasma membrane immunoisolates. Many downstream signaling proteins coisolated with the TCR/LAT-enriched plasma membrane fragments, suggesting that LAT/TCR assemblies form a structural scaffold for TCR signal transduction proteins. Our results indicate that TCR signaling assemblies in plasma membrane subdomains, rather than generally concentrating raft-associated membrane proteins and lipids, form by a selective protein-mediated anchoring of the raft membrane protein LAT in vicinity of TCR.

Emergency department ultrasound scanning for abdominal aortic aneurysm: accessible, accurate, and advantageous

STUDY OBJECTIVE

This study was conducted to determine whether emergency physicians with relatively limited training and experience can accurately identify the presence or absence of abdominal aortic aneurysms (AAAs) by performing bedside ultrasound scanning, and to assess the potential impact of ultrasound scanning on clinical management.

METHODS

Patients in whom AAAs were suspected, including those patients older than 50 years presenting with abdominal/back pain of unclear origin or presumed renal colic, were eligible for study entry. Consenting adults had ultrasound scanning by an emergency physician who was not responsible for their primary care. Treating physicians remained blinded to the results unless an unexpected AAAs was discovered. Scan accuracy was ascertained by comparing our ultrasound results with preselected gold standards. The clinical impact of the ultrasound studies was determined by comparing the preultrasound and postultrasound assessment sheets that detailed the presumed diagnosis, proposed investigations and therapies, and patient disposition.

RESULTS

Our convenience sample includes 68 scans for AAAs; findings of 26 scans were positive, 40 scans yielded negative findings, and 2 scans were indeterminate. Scan interpretations were 100% accurate. The ultrasound results would have improved the care of 46 patients without adverse sequelae. Ultrasound scanning served primarily to exclude AAA in patients who proved not to have aneurysms; however, scans also provided significant benefits for those with AAAs and improved patient management plans.

CONCLUSION

Relative neophytes can perform aortic ultrasound scans accurately. These scans appear useful as a screening measure in high-risk emergency department patients; they may also aid in rapidly verifying the diagnosis in patients who require immediate surgical intervention.

[Immediate hypersensitivity reactions to parenteral glucocorticoids? Analysis of 14 cases]

Immediate hypersensitivity reactions to parenteral glucocorticoids are rare but often serious and life-threatening. In the medical literature some hundred case reports of corticoid hypersensitivity after parenteral administration have been published. The pathomechanism may be immunological or non-immunological in nature and the reaction can be due to the steroid itself or to the excipients. We report on 14 suspected hypersensitivity reactions occurring in 13 patients immediately after parenteral glucocorticoid administration. These cases were reported to the Swiss Drug Monitoring Centre SANZ between 1981 and 1999. 5 out of 26 preparations available in Switzerland and 4 out of the 6 glucocorticoids used for parenteral administration were involved (beta-methasone, methylprednisolone, prednisolone, triamcinolone). 9 reactions were life-threatening: 3 patients experienced an acute asthma attack and 6 a serious anaphylactic reaction including shock. Risk factors were known in 10 patients: allergy was mentioned in 6 patients, and asthma and aspirin-sensitivity in 2 patients each. In 2 patients a clinically relevant cross-reaction with another glucocorticoid was known, while 6 patients tolerated another steroid without problems. Only in 6 cases were skin tests performed: 3 were positive for the preparation, and in one of these cases the skin test was positive for the steroid itself. In 2 cases the hypersensitivity reaction could be traced back to the additive carboxymethylcellulose. Practitioners should be aware of hypersensitivity reactions to glucocorticoids whenever there is a worsening of the clinical status in spite of maximal steroid therapy.

Interaction of Listeria monocytogenes with human brain microvascular endothelial cells: an electron microscopic study

Internalization of Listeria monocytogenes into human brain microvascular endothelial cells (HBMEC) has recently been demonstrated to be dependent upon the inlB gene. In the present scanning electron microscopic study we show that L. monocytogenes efficiently interacts with the surface of HBMEC in an inlB-independent manner which is also different from invasion. The inlB-dependent invasion of HBMEC by L. monocytogenes is accompanied by intracellular multiplication, movement, and production of bacterium-containing protrusions. These protrusions extend from the cell surface without perturbation of any adjacent cellular membrane.

LaXp180, a mammalian ActA-binding protein, identified with the yeast two-hybrid system, co-localizes with intracellular Listeria monocytogenes

The Listeria monocytogenes surface protein ActA is an important virulence factor required for listerial intracellular movement by inducing actin polymerization. The only host cell protein known that directly interacts with ActA is the phosphoprotein VASP, which binds to the central proline-rich repeat region of ActA. To identify additional ActA-binding proteins, we applied the yeast two-hybrid system to search for mouse proteins that interact with ActA. A mouse cDNA library was screened for ActA-interacting proteins (AIPs) using ActA from strain L. monocytogenes EGD as bait. Three different AIPs were identified, one of which was identical to the human protein LaXp180 (also called CC1). Binding of LaXp180 to ActA was also demonstrated in vitro using recombinant histidine-tagged LaXp180 and recombinant ActA. Using an anti-LaXp180 antibody and fluorescence microscopy, we showed that LaXp180 co-localizes with a subset of intracellular, ActA-expressing L. monocytogenes but was never detected on intracellularly growing but ActA-deficient mutants. Furthermore, LaXp180 binding to intracellular L. monocytogenes was asymmetrical and mutually exclusive with F-actin polymerization on the bacterial surface. LaXp180 is a putative binding partner of stathmin, a protein involved in signal transduction pathways and in the regulation of microtubule dynamics. Using immunofluorescence, we showed that stathmin co-localizes with intracellular ActA-expressing L. monocytogenes.

Bacterial replication in the host cell cytosol

Intracellular bacteria in mammalian host cells can either live in a membrane-bound vacuole modified to support bacterial growth, or escape from the primary phagosome into the host cell cytoplasm. Phagosomal escape is best studied in Listeria monocytogenes in which a pore-forming cytolysin and two phospholipases are involved in the lysis of the phagosomal membrane. The mechanisms of and requirements for cytoplasmic growth are less clear but there is growing evidence that proficient replication of bacteria in the cytoplasmic compartment requires specific bacterial and cellular preconditions.

[Potential drug interactions and number of prescription drugs with special instructions at hospital discharge]

OBJECTIVE

Up to 6% of all hospitalizations are due to adverse drug reactions and 20% of these are caused by drug-drug interactions. There is only little information on the prescription frequency of drug-combinations with the potential to induce dangerous drug-drug interactions and drugs with the need for special patient instruction (e.g. inhalers). The aim of our study was to investigate the frequency of such drug prescriptions at hospital discharge.

PATIENTS AND METHODS

In a retrospective, descriptive study drug prescriptions of 100 patients discharged consecutively from the department of internal medicine of a 300 bed-hospital were analysed. Possible drug-drug interactions were detected using a special computer program. Furthermore, the number of prescriptions warranting patient instruction such as anticoagulants, antidiabetics, hormones, immunosuppressive drugs, chemotherapeutics, antituberculotic and antiepileptic drugs as well as inhalatives and injections was recorded.

RESULTS

The mean age of the 100 patients (61 men, 39 women) was 61.7 years, the mean duration of the hospital stay was 9.2 days. At discharge, patients took an average of 3.5 different drugs. Half of the patients were given drug-combinations with the potential for drug-drug interactions, whereby 5% were at risk for the development of interactions of severe and 42% of intermediate degree. All drug-combinations with potentially severe interactions were prescribed deliberately. 31% of all patients took medications with the need for special education, with inhalatives being the most frequent. The prescription of drugs with potential interactions and the necessity for special patient instruction was more frequent in the elderly.

CONCLUSIONS

Drug-combinations with the potential of harmful interactions and drugs with the requirement for special patient instruction are frequently prescribed at hospital discharge. The frequency of prescribing these drugs increases with age. Detection of potentially dangerous drug-drug interactions is simplified by special computer programs. Careful patient instruction about the use of certain drugs is a key issue to improve patient compliance and to guarantee an optimal treatment effect.

Eosinophilic pneumonia and respiratory failure associated with venlafaxine treatment

Drugs are well known causes of eosinophilic lung disease. In many patients, symptoms increase slowly, pulmonary infiltrates and eosinophilia progress over weeks, and resolve upon withdrawal of the offending agent. Rarely, the disease presents like acute eosinophilic pneumonia with acute onset of symptoms and rapidly progressing infiltrates which may be associated with respiratory failure. This report describe a case of venlafaxine-induced acute eosinophilic pneumonia causing respiratory insufficiency that rapidly resolved upon institution of corticosteroid treatment. This 5-hydroxytryptamine and noradrenaline reuptake inhibitor was previously not known to cause lung or peripheral blood eosinophilia. Considering the increasing use of this class of medication physicians have to be aware of this life-threatening and fully reversible complication.

Imaging in the 21st century

The drive for cost reduction and increased quality of therapy (patient outcome) will lead to increasingly less-invasive procedures. As a result, imaging will become essential in the operating theatre environment, simply because the site of the intervention is not visible to the clinician performing it.

Host cell signal transduction during Listeria monocytogenes infection

The facultative intracellular bacterial pathogen Listeria monocytogenes invades and multiplies in many mammalian cell types. During the interaction with its host cells it strongly interferes with and modulates host cell functions. In the present review we summarize the current knowledge on the modulation of signal transduction pathways by secreted listerial products prior to bacterium-cell contact, during uptake, or while L. monocytogenes resides in the different intracellular compartments.

Regulated, side-directed secretion of proguanylin from isolated rat colonic mucosa

Guanylin, an activator of the guanylyl cyclase C receptor in the apical membrane of intestinal epithelium, modulates intestinal fluid and electrolyte transport. The bioactive 15-amino acid peptide originally isolated from rat intestine represents the C-terminal part of a longer, 115-residue prepropeptide. The aim of the present study was to characterize the direction and molecular form in which guanylin is secreted from the colonic mucosa, as well as the mechanisms that trigger its secretion. Isolated rat colonic mucosa was mounted in Ussing chambers, allowing the separate determination of apical and basolateral release. After HPLC purification, two different molecular forms of guanylin were identified in the apical incubation media by combining a bioassay for guanylyl cyclase C activation, a specific guanylin enzyme-linked immunosorbent assay and mass spectrometry, as well as sequence analysis: a bioactive form coeluting with synthetic 15-residue guanylin and the 94-residue propeptide, guanylin-22-115. The basal concentration of proguanylin at the apical side of epithelia was about 15-fold higher, compared with that of the small, bioactive peptide. In the basolateral incubation media, no proguanylin and only very low amounts of bioactive guanylin were detected. Incubation with carbachol led to a significant increase of about 7-fold in the release of proguanylin to both sides of the isolated epithelia. On the apical side, a concomitant increase of the small, bioactive peptide was observed; whereas, on the basolateral side, its concentration remained unchanged. Vasoactive intestinal peptide or the NO-donor S-nitroso-N-acetylpenicillamine did not affect guanylin secretion. Our results suggest that, in the intestine, guanylin is secreted mainly to the luminal side of the epithelium. The peptide is released as a 94-residue propeptide, which is then processed to a smaller, bioactive form (luminocrine secretion). Carbachol stimulates the release of proguanylin to both sides of the intestinal mucosa, but a parallel increase in the bioactive C-terminal derivative only occurs on the apical side. In vivo, the basolateral release could be a source of circulating proguanylin, which might be processed proteolytically to the active peptide in distant target tissues (endocrine secretion).

[Ticlopidine-induced cholestasis]

We report a case of ticlopidine-induced cholestatic hepatitis.

CASE SUMMARY

An 82-year-old man suffered a myocardial infarction in February 1998. Because of persistent angina pectoris a coronary stent was implanted in May 1998. At this time medication with 1 x 250 mg ticlopidine was started in addition to the preexistent medication of aspirin 1 x 100 per day, metoprolol fumarate 1 x 95 mg per day and isosorbide dinitrate 1 x 100 mg per day. Three weeks after starting ticlopidine the patient complained of itching, and on day 28 painless jaundice developed. At this time, the serum activities of alkaline phosphatase (923 U/l), gamma-GT (823 U/l) and total bilirubin concentration (129 mumol/l) were markedly elevated, whereas the activities of the transaminases (AST 131 U/l, ALT 194 U/l) were slightly increased. An extra- or intrahepatic biliary obstruction was ruled out, and there were no signs of a toxic, infectious or immunological cause for the hepatic injury. Liver biopsy showed centro-acinar cholestasis. After drug discontinuation the itching stopped after 4 weeks and jaundice disappeared after 2 weeks. Eight months after the onset of symptoms, the activities of alkaline phosphatase (226 U/l) and gamma-GT (213 U/l) were still elevated but the patient was asymptomatic.

CONCLUSIONS

Ticlopidine-induced mild serum liver enzyme elevations have been observed in some studies (incidence 1-2%). The incidence of severe hepatitis has been estimated at 0.0013%. Only a few cases (in approximately 20 patients receiving ticlopidine) of a severe cholestatic pattern of injury have been reported. In all cases the jaundice resolved and serum liver enzyme concentrations normalised over a period of months. Characteristically, liver biopsies demonstrated centro-acinar cholestasis. Monitoring of serum liver enzyme concentrations is not recommended. When itching or jaundice occur in a patient taking ticlopidine, the possibility of toxic liver damage should be taken into account.