[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.