[Ulcer drugs: profile of side effects of proton-pump blockers in comparison to H2 blockers in the spontaneous reporting system]

Inhibition of gastric acid secretion by drugs remains the most important rational approach to the treatment of acid related diseases. Histamine H2-antagonists and more recently the proton pump blockers have become the first line treatment for acid peptic diseases. Proton pump blockers bind specifically to the proton pump of the parietal cells and thus inhibit the final acid secretion independently from the activating stimuli. Because of this specific mechanism fewer adverse effects on other systems in the body are expected with proton pump blockers than with histamine antagonists. An analysis of the spontaneous reports which the Swiss Drug Monitoring Center (SANZ) received from 1981 to 1995 showed striking differences in the adverse drug reaction profile: hypersensitivity reactions with fever and anaphylactic reactions, liver disorders such as cholestatic hepatitis, most with severe progression and requiring hospitalization, as well as endocrine disorders were reported more frequently with histamine antagonists, skin reactions and joint disorders, however, were reported more often with proton pump blockers. Our data also support the conclusion that adverse drug reactions to proton pump blockers and histamine antagonists are rare in the spontaneous reporting scheme (reporting rate < 1%). There was a somewhat higher rate of serious reports with histamine antagonists. These data do not allow conclusions concerning long-term effects or effects with larger than recommended dosages.

[Liver injury caused by coumarin anticoagulants: experience of the IKS (Intercanton Monitoring Station) and the SANZ (Swiss Center for Drug Monitoring)]

Drug-induced liver diseases are potentially avoidable. Hepatotoxic drugs can mimic virtually any form of liver disease. Among all voluntary adverse drug reaction reports to central registries, 4-7% refer to drug-induced liver diseases. We analyze all cases of coumarin-induced hepatic injuries reported on a voluntary basis to the Swiss Drug Monitoring Centre (SANZ) and the Pharmacovigilance Centre (IKS) from 1981 to 1995. During this period the SANZ collected 9720 reports, 674 of which (6.9%) referred to the liver and the biliary tract. In only 11 reports an oral anticoagulant was involved. In 8 cases we assumed at least a possible causal relationship. 2 more cases were reported directly to the IKS. Among these 10 cases 7 were related to phenprocoumon and 3 to acenocoumarol. In 4 cases elevated concentrations of liver enzymes were measured 2-7 days after the beginning of therapy. In the remaining 6 cases the clinical picture was so severe that the patients had to be hospitalized. These 10 cases are discussed and compared with the cases published in the literature. According to our data, hepatic disorders induced by coumarin-anti-coagulants are rare. If hepatitis is diagnosed in a patient treated with oral anticoagulants, the differential diagnosis of a coumarin-induced hepatic injury has to be considered. Crossreactions between the coumarin derivatives phenprocoumon and acenocoumarol are possible.

[Thromboembolic events in women treated with hormones. Acute cerebrovascular thrombosis in 2 young women receiving ovulation inhibitors, and experiences of SANZ (Swiss Drug Monitoring Center) 1991-1995]

We describe 2 young patients with severe cerebrovascular thrombotic events whose only risk factor was intake of oral contraceptives. A 41-year-old woman suffered thrombosis of the basilar artery and remained disabled with a locked-in syndrome; a 23-year-old woman had thrombosis of the sinus sagittalis. These 2 cases and the current discussion regarding the use of hormones either as oral contraceptives or hormonal replacement therapy with estrogens and/or progestins prompted a review of the literature and a review of all spontaneous reports from 1991 to 1995 to SANZ (Schweizerische Arzneimittel-Nebenwirkungs-Zentrale), the Swiss Drug Side Effects Monitoring Center. The spontaneous reporting under this system does not allow conclusions on prevalence and incidence of adverse events. In these 5 years 33 vascular events associated with different hormones were reported. There were 28 reports of venous thrombosis of the lower and upper limb or pulmonary embolisms, and 5 reports of cerebrovascular complications. In 9 of 33 cases the hormones were used as hormonal replacement therapy and in 24 of 33 cases as oral contraceptives. In half of these women other risk factors for thromboembolic events such as overweight, family history of thrombosis and immobilization were known. Complications occurred with different preparations containing different estrogens and progestins. According to the literature, third generation progestins seem to involve a slightly increased risk of venous thromboembolism but a reduced risk of arterial thromboembolic events, which was confirmed by the SANZ data (17 of all 24 cases). Increasing age and rising estrogen dosage of oral contraceptives are associated with increased risk of vascular events. Although thromboembolic events also occur during hormonal replacement therapy with naturally occurring estrogens, the prophylactic potential of these drugs with regard to osteoporosis and cardiovascular events certainly outweighs this risk.

Urinary excretion of urodilatin in patients with cirrhosis

Cirrhotic patients with ascites show increased plasma levels of natriuretic peptides from cardiac origin (i.e., atrial natriuretic peptide [ANP] and brain natriuretic peptide [BNP]). Urodilatin is a unique member of the natriuretic peptide family because it is exclusively synthesized in the kidney acting on a paracrine fashion in the regulation of sodium excretion. To investigate the renal production of urodilatin in cirrhosis and its relationship with other natriuretic peptides and sodium retention, urodilatin excretion and plasma levels of ANP were measured in 21 healthy subjects, 13 cirrhotic patients without ascites and 23 cirrhotic patients with ascites. Urine urodilatin was measured with a highly specific radioimmunoassay using a polyclonal antibody against human urodilatin. Patients with ascites had marked sodium retention (UNa 7 +/- 2 mEq/d) as compared to patients without ascites and healthy subjects (29 +/- 3 mEq/d and 34 +/- 5 mEq/d, respectively, P < .001). Patients with cirrhosis and ascites had urine urodilatin excretion similar to patients without ascites and healthy subjects (82 +/- 8 pmol/g, 95 +/- 10 pmol/g, and 89 +/- 9 pmol/ g of creatinine, respectively; not significant). In addition, immunoreactive urodilatin from cirrhotic patients with ascites and healthy subjects showed a similar chromatographic pattern. By contrast, plasma ANP levels were increased significantly in patients with ascites (29 +/- 3 fmol/mL) as compared with patients without ascites or healthy subjects (14 +/- 3 fmol/mL and 6 +/- 1 fmol/mL, respectively; P < .01). In conclusion, urine urodilatin excretion is normal in patients with cirrhosis even in the presence of marked sodium retention. The coexistence of increased ANP levels and normal urodilatin excretion suggests that in cirrhosis both natriuretic peptides are regulated independently.

Guanylin strongly stimulates rat duodenal HCO3- secretion: proposed mechanism and comparison with other secretagogues

BACKGROUND & AIMS

Guanylin and heat-stable enterotoxin (STa) stimulate intestinal Cl- secretion via activation of the cystic fibrosis transmembrane regulator (CFTR)-encoded Cl- channel. It was speculated that CFTR activation also regulates electrogenic duodenal HCO3- secretion. Therefore, the effect of guanylin/STa and other secretagogues on rat duodenal HCO3- secretion was studied.

METHODS

The HCO3- secretory rate of in vitro rat proximal duodenum was determined by pH stat titration and paracellular permeability by 3H-mannitol fluxes, bidirectional 36Cl- fluxes were measured, and the short-circuit current (Isc) was recorded.

RESULTS

Luminal guanylin and STa concentration dependently stimulated the HCO3- secretory rate and Isc. Guanylin-stimulated HCO3- secretion was independent of luminal Cl-, inhibited by the Cl- channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoate, and additive to the HCO3- secretory rate stimulated by glucagon and carbachol but not by the tested adenosine 3',5'-cyclic monophosphate (cAMP)-dependent agonists. The ratio of the HCO3- secretory rate/Isc stimulated by the tested guanosine 3',5'-cyclic monophosphate (cGMP)-dependent agonists was markedly higher than the cAMP-dependent agonists. Prostaglandin E2 and 8-bromo-cAMP but not STa/guanylin also transiently increased paracellular permeability.

CONCLUSIONS

Guanylin and STa stimulate electrogenic HCO3- secretion in rat duodenum, most likely via CFTR Cl- channel activation, but the different relationship for HCO3- to Isc in cGMP-than in cAMP-stimulated anion secretion suggests a different cellular source and/or signaling pathways.

cGMP-activating peptides do not regulate electrogenic electrolyte transport in principal cells of rat CCD

K+ channels in the basolateral membrane of rat cortical collecting duct (CCD) are regulated by a cGMP-dependent protein kinase (J. Hirsch and E. Schlatter. Pfluegers Arch. 429: 338-344, 1995). Conflicting data exist on the effects of cGMP-activating agonists on Na+ transport in these cells. Thus we tested members of the family of peptides that increase intracellular cGMP [cardiodilatin/atrial natriuretic peptide (CDD/ANP), brain natriuretic peptide, C-type natriuretic peptide, urodilatin, guanylin, and uroguanylin], as well as bradykinin +/- CDD/ANP on membrane voltages (Vm) of principal cells of isolated rat CCD using the slow whole cell patch-clamp technique (E. Schlatter, U. Fröbe, and R. Greger. Pfluegers Arch. 421: 381-387, 1992). None of the agonists tested changed Vm significantly. There was also no effect of dibutyryl guanosine 3',5'-cyclic monophosphate (DBcGMP) on AVP-dependent lumen-to-bath Na+ flux, transepithelial voltage, or osmotic water permeability in isolated perfused rat CCD. Finally, CDD/ANP increased intracellular cGMP only in glomeruli but not in CCD. Thus the findings provide no evidence for control of electrogenic electrolyte transport by these natriuretic peptides in principal cells of rat CCD, and the agonist that physiologically regulates the cGMP-dependent K+ channels remains to be identified.

[Drug-induced taste disorders]

Taste disorders may have diverse uncomfortable consequences such as reduced quality of life, weight loss and possibly professional disability. The sense of taste depends on many factors. Thus various conditions may cause taste disorders, drugs being one of them. The list of drugs being able to cause taste disorders as adverse drug reaction is long and there are many such cases reported to the Swiss Drug Monitoring Center (SANZ). The possibility of an unwanted side effect should be taken into account if a patient complains about taste disorders, such as reduced or changed sense of taste.

Extensible biosignal (EBS) file format: simple method for EEG data exchange

Increasing use of computer technology in EEG research requires the creation of standardized data formats to transmit, exchange, analyze or modify mainly EEG/MEG as well as mere general polygraphic data. The extensible biosignal file format (EBS) has been designed for easy use. The concept of the EBS format is a simple structure of variable size, consisting of one fixed and two variable headers and a data section. In the variable header, any information can be stored in attributes. The data are archived in one of 3 organizational forms: channel order, temporal order, or compressed. The format supports various data types, multiple biosignals (ECG, EEG, MEG, polygraph), annotations, processing history, location diagrams (CGM), 16 hit ISO 10646 character set, random access to large amounts of data, global or private extensions, self-identification, and multiple tools for conversion, modification and visualization which are freely available in source code.

[Side effects of drugs on the respiratory tract: experiences of the Swiss Drug Monitoring Center from 1991 to 1995]

Between 1991 and 1995 about 3% of the unwanted drug-induced side effects reported to the Swiss Drug Monitoring Center (SANZ) concerned pulmonary disturbances (144 out of a total of 4824 reports). The most frequent reports were those about cough and taste disorders caused by ACE-inhibitors, smell disorders caused by antimicotics, and asthma attacks caused by nonsteroidal antirheumatics or betablocking eye drops. 33% of these unwanted side effects have been classified as severe. By spontaneous reporting a correct calculation of incidence is not possible. The reports, however, have signal function. Precise case analysis, temporary correlations (reaction and exposure time and onset of reaction), exclusion of other causes for the disease, comparisons between similar cases and critical study of literature concerning drug-related side effects are still the most important foundations for diagnosis.

Recombinant human erythropoietin enhances vasoconstrictor tone via endothelin-1 and constrictor prostanoids

Hypertension is the main side effect developing in patients suffering from renal anemia who are treated with recombinant human erythropoietin (rHuEPO). We investigated the effect of rHuEPO on the vascular tone of isolated rabbit aorta and carotid artery under isometric conditions. The production of prostacyclin and the vasoconstrictor prostanoids PGF2 alpha and TXB2 was investigated in arterial rings incubated with rHuEPO. Endothelial cells from human umbilical veins (HUVECs) were isolated and cultured in flasks (37 degrees C, 5% CO2). After incubation with rHuEPO, the formations of prostacyclin (as its stable metabolite 6-keto-PGF1 alpha), PGF2 alpha, PGE2, thromboxane (TX) B2 and of ET-1 were measured by radioimmunoassays. rHuEPO had no direct vasoconstrictor effect, but it enhanced noradrenalin-induced contractions. This effect was more prominent in rings with intact endothelium than in rings from which the endothelium had been mechanically removed, indicating that endothelial vasoactive factors might be involved. Relaxations to acetylcholine (ACh, 1 microM) were unaltered in the presence or absence of rHuEPO, suggesting that the endothelial NO-cGMP pathway was not impaired by rHuEPO. Incubation with rHuEPO (20 to 200 U/ml) increased the release of the vasoconstrictor mediators ET-1, PGF2 alpha and TXB2, and decreased prostacyclin formation in isolated rabbit arterial rings and in HUVECs, respectively. The cyclooxygenase inhibitor indomethacin abolished the rHuEPO-induced increase in vasoconstrictor prostanoid production. ET-1 formation by HUVECs was also increased by rHuEPO in a dose-dependent manner (maximal effect +90% by rHuEPO 200 U/ml, P < 0.05). Indomethacin and the selective ETA receptor antagonist BQ123 each partly inhibited the enhancement of vascular responsiveness to noradrenalin induced by rHuEPO in rabbit carotid artery, but simultaneous administration of rHuEPO with both antagonists completely abolished the force increment. In conclusion, these studies show that a dose-dependent shift in the balance of constrictor and relaxing prostanoids as well as an increased synthesis of ET-1 induced by rHuEPO lead to the enhanced vascular responsiveness to noradrenalin in isolated rabbit arteries. The increased vascular responsiveness to noradrenalin, which is in line with clinical observations, may contribute to the hypertensive side effect associated with rHuEPO therapy in patients with chronic renal failure.

Localization, expression, and characterization of guanylin in the rat adrenal medulla

The peptide guanylin, recently isolated from the intestine, and localized to cells of the gut mucosa, is involved in electrolyte/water transport in the intestinal epithelium by means of a paracrine mode of regulation. Since high amounts of this peptide are present also in the systemic circulation, we investigated the adrenal gland as a potential endocrine source of guanylin. Using a reverse transcriptase-polymerase chain reaction and hybridization with an internal oligonucleotide designed for rat guanylin, 514-bp signals were obtained in intestinal tissue and adrenal gland. Successive analyses of extracts from intestine and adrenal gland by HPLC, western blotting, and radioimmunoassay revealed the presence of the same high-molecular mass (about 12.4 kDa) guanylin that corresponds to the mass of the guanylin prohormone. About 60 fmol/ml of circulating immunoreactive guanylin was determined in plasma. Localization studies with antisera directed against different epitopes of guanylin revealed that, in the adrenal gland, guanylin immunoreactivity is restricted to the medulla, where it is mainly confined to norepinephrine chromogranin A-containing cells. On the ultrastructural level, guanylin immunoreactivity was exclusively located to secretory granules of chromaffin cells. The present data indicate that, in addition to entero-endocrine cells, the adrenal medulla represents a further source of guanylin. Thus, an endocrine mode of function of guanylin may accrue to its hitherto evidenced paracrine action in fluid transport in the intestinal epithelium. Furthermore guanylin may be considered as a neurohormonal peptide.

Site-directed mutations affecting the spectroscopic characteristics and midpoint potential of the primary donor in photosystem I

Photosystem I is a member of the iron-sulfur center or type I reaction centers. The primary electron donor in photosystem I is a chlorophyll a dimer termed P700. The biophysical properties of P700 are well understood, but the protein environment that gives it such unique properties is unknown. We have characterized site-directed mutants of the photosystem I reaction center protein PsaB and identified an amino acid, His-656, that interacts closely with one of the P700 chlorophylls. Mutation of His-656 to Asn or Ser increases the oxidation midpoint potential of P700/P700+. by 40 mV. The P700/P700+. optical difference spectra show the appearance of a new bleaching band at 667 nm. Electron nuclear double resonance spectroscopy indicates a significant increase in the hyperfine coupling corresponding to methyl protons at position 12 of the spin carrying chlorophyll a of P700+. The implication of these results to current structural models of the photosystem I reaction center is discussed.

Differential regulation of cytokine and cytokine receptor mRNA expression upon infection of bone marrow-derived macrophages with Listeria monocytogenes

Cytokine and cytokine receptor mRNA expression was analyzed by PCR-assisted amplification of RNA extracted from bone marrow-derived macrophages (BMM phi) at different time points after infection with Listeria monocytogenes. The mRNAs for the cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, and tumor necrosis factor alpha (TNF-alpha) were induced early after infection, whereas IL-6 mRNA appeared later and even nonhemolytic Listeria strains, which are unable to grow inside eukaryotic cells, induced the same cytokine mRNAs at levels similar to those of the wild-type strain. In most cases, the amounts of cytokines determined by various bioassays correlated with the level of mRNA induction. Inhibition of phagocytic uptake of L. monocytogenes by cytochalasin D treatment resulted in adherent bacteria which still induced the proinflammatory cytokines. In BMM phi, the level of IL-1 receptor II mRNA was unaffected, whereas mRNA expression of the two subtypes of tumor necrosis factor receptors (TNF-RI and TNF-RII) was differentially regulated upon infection: transcription of TNF-RI was reduced, and that of TNF-RII mRNA was induced. Similar to the decreased TNF-RI mRNA expression, gamma interferon receptor mRNA was downregulated in L. monocytogenes-infected BMM phi. This dose- and time-dependent induction or downregulation of cytokine receptor mRNA following L. monocytogenes infection of BMM phi was not observed upon infection of established macrophage-like cell lines J774 and P388D1. Induction of IL-6 mRNA as well as IL-1 alpha/beta and TNF-alpha mRNAs upon L. monocytogenes infection of BMM phi occurs independently of autocrine TNF-alpha signaling via TNF-RI or TNF-RII, as shown by infection of TNF-RI- and TNF-RII-deficient macrophages derived from mutant B6 x 129 mice. In contrast to gamma interferon receptor mRNA, both TNF receptor subtype mRNAs were not influenced by L. monocytogenes infection of hybrid (B6 x 129) mouse macrophages. Whereas the proinflammatory cytokine mRNAs were even induced after infection with the nonpathogenic species L. innocua, no alteration of cytokine receptor mRNA expression was observed after challenge of BMM phi with this nonpathogenic species, suggesting that the modulation of cytokine and cytokine receptor expression by L. monocytogenes could be an important way of inhibition of macrophage stimulation.

Effects of hydrogen bonding to a bacteriochlorophyll-bacteriopheophytin dimer in reaction centers from Rhodobacter sphaeroides

The properties of the primary electron donor in reaction centers from Rhodobacter sphaeroides have been investigated in mutants containing a bacteriochlorophyll (BChl)--bacteriopheophytin (BPhe) dimer with and without hydrogen bonds to the conjugated carbonyl groups. The heterodimer mutation His M202 to Leu was combined with each of the following mutations: His L168 to Phe, which should remove an existing hydrogen bond to the BChl molecule; Leu L131 to His, which should add a hydrogen bond to the BChl molecule; and Leu M160 to His and Phe M197 to His, each of which should add a hydrogen bond to the BPhe molecule [Rautter, J., Lendzian, F., Schulz, C., Fetsch, A., Kuhn M., Lin, X., Williams, J. C., Allen J. P., & Lubitz, W. (1995) Biochemistry 34, 8130-8143]. Pigment extractions and Fourier transform Raman spectra confirm that all of the mutants contain a heterodimer. The bands in the resonance Raman spectra arising from the BPhe molecule, which is selectively enhanced, exhibit the shifts expected for the addition of a hydrogen bond to the 9-keto and 2-acetyl carbonyl groups. The oxidation--reduction midpoint potential of the donor is increased by approximately 85 mV by the addition of a hydrogen bond to the BChl molecule but is only increased by approximately 15 mV by the addition of a hydrogen bond to the BPhe molecule. An increase in the rate of charge recombination from the primary quinone is correlated with an increase in the midpoint potential. The yield of electron transfer to the primary quinone is 5-fold reduced for the mutants with a hydrogen bond to the BPhe molecule. Room- and low-temperature optical absorption spectra show small differences from the features that are typical for the heterodimer, except that a large increase in absorption is observed around 860-900 nm for the donor Qy band in the mutant that adds a hydrogen bond to the BChl molecule. The changes in the optical spectra and the yield of electron transfer are consistent with a model in which the addition of a hydrogen bond to the BChl molecule increases the energy of an internal charge transfer state while the addition to the BPhe molecule stabilizes this state. The results show that the properties of the heterodimer are different depending on which side is hydrogen-bonded and suggest that the hydrogen bonds alter the energy of the internal charge transfer state in a well-defined manner.

Fluorescent fiber-optic calcium sensor for physiological measurements

A new optical sensor based on covalent immobilization of a newly synthesized calcium-selective, long-wavelength, fluorescent indicator has been constructed, with a response dynamic range optimal for physiological measurements. Immobilization occurs via photoinitiated copolymerization of the indicator with acrylamide on the distal end of a silanized 125 micrograms diameter multimode optical fiber. The working lifetime of this sensor is limited only by photobleaching of the indicator. Due to the inherent hydrophilic nature of the acrylamide polymer, the response time of this new sensor is governed by simple aqueous diffusion of the ionic calcium. This results in sensor response times fast enough to monitor some concentration fluctuations at physiological rates. The ability to monitor calcium concentration fluctuations in a high background level of magnesium is also demonstrated with a calculated selectivity of 10(-4.5).

[Fulminant, rapidly reversible hepatitis and life-threatening anaphylaxis following rifampicin in an HIV-positive female patient with latent adrenal cortex insufficiency]

We report the case of a 28-year-old-prostitute from Thailand with HIV infection stage B2 associated with retroperitoneal lymph node tuberculosis. 6 days after the beginning of anti-tuberculous therapy (isoniazid, rifampicin, pyrazinamid and ethambutol) the temperature rose to 40.5 degrees C, diarrhea, vomiting, and tachycardia developed and systolic blood pressure fell to 80 mm Hg. Liver function tests revealed acute hepatic failure (ALT 800 IU/l rising to 1500; serum bilirubin 89 mumol/l rising to 238.0; alkaline phosphatase 199 IU/l; glucose 1.8 mmol/l; prothrombin time 20%). Isoniazid, rifampicin, and pyrazinamid were replaced by streptomycin and PAS. A few days after withdrawal the liver profile returned to normal. Hours after the reintroduction of rifampicin total body erythema, pruritus, vomiting and severe hypotension developed, requiring saline methylprednisolone and epinephrine administration. The next reexposure to intravenous rifampicin produced a rash and was rapidly discontinued. Liver function tests remained normal. Later mild adverse reactions to streptomycin and pyrazinamid occurred, two drugs which had been well tolerated before. Subsequently the diagnosis of adrenal insufficiency was established. After initiation of steroid replacement (50 mg prednisolone) the antituberculous therapy with isoniazid, pyrazinamid and ethambutol was well tolerated. We conclude that the shock in this HIV-infected patient was either due to severe anaphylaxis to rifampicin or acute adrenal insufficiency ensuing on this drug. The reversible fulminant acute hepatic failure represents either an adverse effect of antituberculous drugs, especially hepatotoxic interactions of drug combinations, or an ischemic liver injury during hypotension caused by anaphylaxis. The case illustrates the complex nature of side effects of antituberculous drugs in HIV patients and their aggravation by adrenal insufficiency.

Topical anaesthesia for minor lacerations: MAC versus TAC

OBJECTIVE

To determine whether a solution of bupivacaine Marcain [Astra]), adrenaline and cocaine (MAC) is as safe and effective as tetracaine, adrenaline and cocaine (TAC) as topical anaesthesia for wound suturing.

DESIGN

Double-blind, randomised, prospective trial.

SETTING

Emergency departments of two tertiary referral hospitals (one specialising in paediatric care) in Adelaide, South Australia, between February 1992 and April 1994.

PARTICIPANTS

181 patients, aged six or older, with simple dermal lacerations less than 5mm deep, not involving mucous membranes or areas with end-arterial blood supply.

INTERVENTIONS

Patients received a weight-adjusted dose of either MAC or TAC.

OUTCOME MEASURES

Needle-prick testing of wound for pain before suturing, pain ratings by patients and physicians during suturing, signs and symptoms of cocaine toxicity, wound complications and patient preference for topical anaesthesia.

RESULTS

Topical anaesthesia was adequate for suturing in 73% of patients (83% or those with head wounds and 56% of those with extremity wounds). MAC and TAC did not differ significantly in efficacy overall or by wound location. Pain ratings from patients treated with MAC and TAC were comparable, as was patients acceptance of topical anesthesia (77%, MAC; 81%, TAC) and the incidence of adverse effects (4% infection rate overall).

CONCLUSIONS

Topical anesthesia is a safe and effective means of anaesthetising selected lacerations for suturing. As we found no significant differences in either the efficacy or safety of the two solutions, we believe that MAC can be substituted for the less readily available TAC whenever expedient.

Genetic markers linked to quantitative traits in poultry

This study utilized DNA fingerprints and crosses of two genetically distinct lines of layer-type chickens to identify genetic markers linked to quantitative trait loci (QTL). In phase I, backcross (BC1) hens were separately ranked for each of eight traits and then blood pools were produced in groups along each phenotypic distribution. The DNA was isolated from the blood pools and used in a gradient analysis to screen for DNA fingerprint bands that exhibited intensity gradients associated with the phenotypic traits. To identify linkage of bands with QTL and to estimate band effects, F2 progeny were produced in phase II from the phase I BC1 population. A single-trait animal model was used for analysis of associations of all individual DNA fingerprint bands of sires and their progeny phenotypic performance. Twenty fingerprint bands, only two of which had shown trait-associated gradients in phase I, were identified by the animal model analysis of the progeny test as QTL linked (P < or = 0.05) to specific traits of growth, reproduction and egg quality. These 20 bands warrant further study as potentially valuable molecular markers for QTL.

[Problems in the diagnosis and therapy of lymph node tuberculosis in HIV-negative patients]

Tuberculosis is the world's foremost cause of death from a single infectious agent in adults. During the past decade the nature and magnitude of the problem of tuberculosis have dramatically changed. Much of what physicians have learned about this disease is no longer true and tuberculosis has become a new entity. Migration from developing areas with a high prevalence of tuberculosis to industrialized countries, and the problem of HIV infection, have introduced new components to the epidemiology. We report three cases of young immigrants with lymph node tuberculosis. One patient was successfully treated with the usual 9-month-regimen. The other 2 patients, however, developed new lymph nodes or enlargement of existing nodes during treatment. They underwent further examinations, including surgical biopsies, because of diagnostic uncertainty (tuberculosis, superinfection or lymphoma). Finally the 2 patients were successfully treated with antituberculous agents for 12 and 15 months. These cases prompted a review of the literature and a reevaluation of the management of lymph node tuberculosis, including the value of surgical biopsy in the diagnosis of tuberculous lymphadenitis. We conclude that selective surgical biopsies should be recommended for differential diagnosis of tuberculous lymphadenitis. Histological examination (caseating epitheloid cell granulomas and giant cell formation) and microbiological examination (Ziehl-Neelsen staining and culture of native material) should be performed. Newer methods, such as amplification and detection of mycobacterial DNA, are rapid and sensitive tests helpful for diagnosis. Lymph nodes may increase in size and new nodes may appear both during and after chemotherapy, without indicating a failure of treatment or relapse. The usual treatment is a 9-month-regimen with rifamipicin, isoniazid, pyrazinamid and ethambutol. Prolonged or modified regimens are, however, necessary in some individuals.

Circulating and tissue guanylin immunoreactivity in intestinal secretory diarrhoea

Guanylin is a recently discovered peptide hormone that activates intestinal guanylate cyclase (GC-C) and thereby stimulates intestinal chloride secretion. Immunohistochemistry showed its presence in enterochromaffin (EC) cells of the gut. In vitro studies suggested that guanylin plays an important role in the endogenous modulation of intestinal salt and water secretion. In the present study the concentration of circulating immunoreactive (IR)-guanylin in plasma of patients with intestinal diarrhoea due to chronic bowel inflammation and patients with carcinoid tumours were measured with a specific radioimmunoassay. In 22 patients with Crohn's disease and eight patients with ulcerative colitis, plasma concentrations of IR-guanylin were 44 +/- 3 and 42 +/- 4 fmol mL-1, respectively. Levels were not different from that in 44 healthy volunteers suggesting that the circulating hormone is not involved in diarrhoea of these patients. In 17 patients with symptomatic carcinoid tumors the median concentration of circulating IR-guanylin was significantly enhanced (94 +/- 16 fmol mL-1, range 37-312 fmol mL-1). Immunohistochemistry revealed the presence of immunoreactive guanylin in carcinoid tissues, suggesting that these tumours co-release guanylin along with their usual resident hormone, serotonin. Enhanced local secretion of guanylin may play a causal role in diarrhoea of these patients and its elevation in plasma may be of diagnostic value in this type of endocrine tumours.

Pituitary adenylate cyclase-activating polypeptide stimulates cardiodilatin/atrial natriuretic peptide (CDD/ANP-(99-126) secretion from cultured neonatal rat myocardiocytes

It has been reported that the highly homologous neuropeptides pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal polypeptide (VIP) exert similar cardiovascular effects in vivo. In the present study we compared the effects of these neuropeptides on myocardial cyclic AMP content and the release of immunoreactive CDD/ANP-(99-126) (atrial natriuretic peptide). In cultured neonatal rat cardiomyocytes PACAP and VIP evoke concentration-dependent increases in intracellular cyclic AMP content but responses to VIP are markedly less. PACAP stimulates the release of CDD/ ANP-(99-126) in a concentration-dependent manner with a threshold concentration of 1 nM, and up to a 6-fold increase in basal secretion at 1 microM PACAP. In contrast. VIP had no effect on the release of CDD/ANP. Pretreatment of cells with the competitive PACAP-antagonist, PACAP-6-38 (1 microM), significantly reduces the effects of PACAP on intracellular cyclic AMP and on CDD/ANP-(99-126) secretion and abolishes the effects of VIP on cyclic AMP. Pretreatment with VIP-receptor antagonist (1 microM) prevents the cyclic AMP-response to VIP while increases in cyclic AMP as well as stimulation of CDD/ANP-(99-126) release by PACAP are not affected. It is concluded that both neuropeptides directly influence cardiac myocytes through an increase in intracellular cyclic AMP. Release of CDD/ ANP-(99-126) by PACAP may be involved in the decrease in blood pressure that follows intravenous administration of this peptide. The higher potency of PACAP to induce cyclic AMP synthesis, its stimulating effect on the release of CDD/ANP-(99-126) and the finding that the VIP-receptor antagonist inhibits responses to VIP but not to PACAP suggest that PACAP activates cardiac myocytes through a PACAP-specific receptor.

GCAP-II: isolation and characterization of the circulating form of human uroguanylin

The systematic isolation of circulating regulatory peptides which generate cGMP as second messenger resulted in the identification of a novel member of the guanylin family. In the present study we describe the purification and amino acid sequence of a new guanylate cyclase C activating peptide (GCAP-II). GCAP-II contains 24 amino acids in the following sequence: FKTLRTIANDDCELCVNVACTGCL. Its molecular mass is 2597.7 Da. The 16 C-terminal amino acids are identical to uroguanylin from human urine. native and synthetic GCAP-II activate GC-C, the specific guanylate cyclase receptor, of cultured human colon carcinoma (T84) cells. GCAP-II stimulates chloride secretion in isolated human intestinal mucosa mediated by intracellular cGMP increase. GCAP-II specific antibodies were used to localize the peptide by immunohistochemistry in entero-endocrine cells of the colonic mucosa.

Salmonella strain secreting active listeriolysin changes its intracellular localization

We describe the construction of an attenuated Salmonella dublin aroA strain which secretes via the Escherichia coli hemolysin secretion machinery an active hybrid cytolysin consisting of listeriolysin from Listeria monocytogenes and the C-terminal secretion signal of E. coli hemolysin. This hemolytic S. dublin strain is partially released into the cytoplasm of the host cell following uptake by J774 macrophage cells, whereas the nonhemolytic control S. dublin aroA strain remains in the phagosome.

ENDOR studies of the primary donor cation radical in mutant reaction centers of Rhodobacter sphaeroides with altered hydrogen-bond interactions

The electronic structure of the cation radical of the primary electron donor was investigated in genetically modified reaction centers of Rhodobacter sphaeroides. The site-directed mutations were designed to add or remove hydrogen bonds between the conjugated carbonyl groups of the primary donor, a bacteriochlorophyll dimer, and histidine residues of the protein and were introduced at the symmetry-related sites L168 His-->Phe, HF(L168), and M197 Phe-->His, FH(M197), near the 2-acetyl groups of the dimer and at sites M160 Leu-->His, LH(M160), and L131 Leu-->His, LH(L131), in the vicinity of the 9-keto carbonyls of the dimer. The single mutants and a complete set of double mutants were studied using EPR, ENDOR, and TRIPLE resonance spectroscopy. The changes in the hydrogen bond situation of the primary donor were accompanied by changes in the dimer oxidation midpoint potential, ranging from 410 to 710 mV in the investigated mutants [Lin, X., Murchison, H. A., Nagarajan, V., Parson, W. W., Williams, J. C. & Allen, J. P. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 10265-10269]. It was found that the addition or removal of a hydrogen bond causes large shifts of the spin density between the two halves of the dimer. Measurements on double mutants showed that the unpaired electron can be gradually shifted from a localization on the L-half of the dimer to a localization on the M-half, depending on the hydrogen bond situation. As a control, the effects of the different hydrogen bonds on P.+ in the mutant HL(M202), which contains a BChlL-BPheM heterodimer as the primary donor with localized spin on the BChl aL [Bylina, E. J., & Youvan, D. C. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 7226-7230; Schenck, C. C., Gaul, D., Steffen M., Boxer S. G., McDowell L., Kirmaier C., & Holten D. (1990) in Reaction Centers of Photosynthetic Bacteria (Michel-Beyerle M. E., Ed.) pp 229-238, Springer, Berlin] were studied. In this mutant only small local changes of the spin densities (< or = 10%) in the vicinity of the hydrogen bonds were observed. The effects of the introduced hydrogen bonds on the spin density distribution of the dimer in the mutants are discussed in terms of different orbital energies of the two BChl a moieties which are directly influenced by hydrogen bond formation. The observed changes of the spin density distribution for the double mutants are additive with respect to the single mutations.(ABSTRACT TRUNCATED AT 400 WORDS)

Modification of the Fontan procedure. Superior vena cava to left pulmonary artery connection and inferior vena cava to right pulmonary artery connection with adjustable atrial septal defect

BACKGROUND

A modification of the Fontan procedure with unidirectional cavopulmonary connection is described in which the superior vena cava (SVC) is connected to the left pulmonary artery (PA) and the inferior vena cava (IVC) is connected to the right PA via a lateral tunnel with a snare-controlled, adjustable atrial septal defect (ASD). This allows matching of the SVC and IVC flows with the lung of appropriate size. The obligatory left Glenn shunt provides an adequate arterial oxygen saturation, and the elevation in SVC pressure is well tolerated. The adjustable ASD allows selective decompression of the IVC that maintains cardiac output and reduces fluid accumulation in the serous cavities.

METHODS AND RESULTS

Since March 1992, we have performed this procedure in 18 patients. There were 17 children and 1 adult. Median age was 3 years and 9 months (range, 13 months to 36 years). Six patients had been staged with a previous bidirectional Glenn shunt. Preoperative cardiac catheterization revealed a PA pressure of 13 +/- 2 mm Hg and a transpulmonary gradient of 5 +/- 3 mm Hg. Ventricular function was satisfactory in all patients. At the completion of bypass, the pressures in the SVC and IVC were 16 +/- 4 mm Hg and 10 +/- 3 mm Hg, respectively (P < .01). The left atrial pressure was 6.0 +/- 3.0 mm Hg and the arterial O2 saturation on 100% oxygen was 93 +/- 3%. There was one death as a result of intractable atrial arrhythmias. The remaining 17 patients had a mean hospital stay of 9.7 days (6 to 18 days). The length of pleural drainage was 7 +/- 3 days. The ASD was adjusted in 11 patients before discharge. Oxygen saturation at discharge was 85.4 +/- 4%. Nine patients had repeat catheterization. The ASD was completely closed in 6 patients, an average of 2.5 months after surgery (range, 3 weeks to 5 months). After ASD closure, the arterial oxygen saturation was 96 +/- 3%, and the SVC and IVC pressures were both 13 +/- 3 mm Hg.

CONCLUSIONS

The Fontan procedure with unidirectional cavopulmonary connection and adjustable ASD has several advantages that may reduce mortality and morbidity for the high-risk Fontan candidate.

Late outcome of percutaneous dilatational tracheostomy in intensive care patients

OBJECTIVE

Percutaneous dilatational tracheostomy is increasingly practiced in intensive care units and has a low incidence of early complications. The late effects of this procedure are still poorly known and were the focus of this study.

DESIGN

Prospective descriptive clinical study.

SETTING

Interdisciplinary intensive care unit in a 300-bed teaching hospital.

PATIENTS

A consecutive group of critically ill patients who underwent percutaneous tracheostomy between Nov. 90 and March 93, surviving at least 2 months after decannulation.

MEASUREMENTS AND RESULTS

There were 17 patients fulfilling the inclusion criteria and 16 of them were seen and examined. The follow-up protocol required a formal standardized patient interview, a physical examination of the stoma site and a fiberoptic laryngotracheoscopy. Results of these sub-tests and overall outcome rating were standardized and expressed as good, moderate or poor. Subjective rating was good in all patients. All denied suffering from any side effects of their tracheostomy. Clinical examination revealed neither stridor nor hoarseness in any of the patients. Most of the scars were whitish and less than 1 cm in length, a few were sunken in, none had adhesions. In 15 patients the clinical result was good and in one, moderate (whitish, sunken-in scar, longer than 2 cm). Ten patients underwent tracheoscopy, while 6 did not. There were no signs of significant stenosis or tracheomalacia. In 8 patients with minor findings results were scored as good, while 2 were classified as moderate (combination of swelling and scar formation of a string-like membrane). The overall rating was good in 13 patients (81%) and moderate in 3 patients (19%). There were no poor outcomes.

CONCLUSIONS

Late outcome of percutaneous dilatational tracheostomy in critically ill patients is mostly good. Pending further studies, the use of this technique in intensive care units appears justified.

[Drug-induced pancreatitis: experience of the Swiss Drug Adverse Effects Center (SANZ) 1981-1993]

Acute pancreatitis may be caused by a number of different drugs. However, reports on the frequency of drug-related acute pancreatitis and on the drugs involved are rare. We therefore investigated all cases of drug-related acute pancreatitis which had been reported to the Swiss Drug Monitoring Center (Schweizerische Arzneimittel-Nebenwirkungszentrale, SANZ) between 1981 and 1993. During this period the total number of reported adverse drug reactions was 7338, 20 of which (0.3%) were considered to be probable cases of drug-related pancreatitis. In 18 cases a single drug was incriminated, whereas in two cases two and four drugs respectively had to be investigated. Serious courses, deaths, or chronic pancreatitis were not reported. The most frequent single drugs incriminated were sulfonamide derivatives (5 cases), valproic acid (3 cases) and nonsteroidal anti-flammatory drugs (2 cases). The frequencies reported here are consistent with the literature. Considering the total number of drugs prescribed, acute pancreatitis is a rare adverse drug reaction.

[Meningoencephalo-myeloradiculitis due to Flavivirus: bi-brachial paralysis and respiratory insufficiency]

3 patients developed rapid onset of fever and nuchal stiffness. Paresis of brachial muscles occurred within 4 days and all patients had respiratory failure that needed mechanical ventilation. At the peak of the disease there were bilateral asymmetrical severe atrophy of brachial, shoulder and neck muscles, cranial nerve pareses and absent or weak deep reflexes in the upper extremities. CSF analyses showed sterile lymphocytic pleocytosis. In 2 cases the patients suffered a tick bite in Switzerland and the third was probably bitten by an insect while opening a package received from Indonesia. Patients had rapid defervescence and serological tests were found to be highly positive for IgM and then IgG ELISA FSME (Frühsommer-Meningoenzephalitis). The patients were ventilated for 2 to 5 weeks before a progressive improvement was seen. However, on follow-up at 12, 18 and 30 months respectively, proximal muscles were still atrophied and quite weak. Our cases underline that: (1) FSME-ELISA results may cross-react with the Japanese and Central European encephalitis virus species; (2) Flaviviruses do induce unusual and preferential long-term paralysis of the upper extremities simulating poliomyelitis; (3) in the 2 patients studied electrophysiologically, there were signs of axonal reinnervation not seen in lower motor neuron syndrome which were important for reinnervation to permit progressive, but late, motor improvement; (4) there is no evidence of extension of the endemic foci of tick-borne encephalitis in Switzerland.

Analysis of the human guanylin gene and the processing and cellular localization of the peptide

The complete cell biological analysis of human guanylin, a recently discovered regulatory peptide, is offered in this investigation: (i) the nucleotide sequence of the gene, (ii) the isolation and characterization of its circulating molecular form, and (iii) its localization in enterochromaffin cells of the gut. As determined by molecular cloning, DNA sequencing, and comparison with the known cDNA sequence, the approximately 2.6-kbp large gene consists of three exons interrupted by two introns. The putative promoter region contains a TTTAAAA sequence motif and several potential binding sites for transcription factors such as AP-1, AP-2, Sp 1, and glucocorticoid receptors. The isolated hormonal form of guanylin is a 94-amino acid peptide with a molecular mass of 10.3 kDa. Western blot analysis of RP-HPLC fractions from blood plasma confirms this molecular form. Thus, guanylin is synthesized by gut enterochromaffin cells as a prohormone of 115 amino acids and is processed to the molecular form of 94 amino acids circulating in the blood.

Site-directed mutagenesis of conserved histidines in the helix VIII domain of PsaB impairs assembly of the photosystem I reaction center without altering spectroscopic characteristics of P700

The chloroplast psaB gene encodes one of the polypeptides of the photosystem I reaction center heterodimer that coordinates the electron transfer components P700, A0, and A1. Histidine residues in the most highly conserved region of the PsaB protein are predicted to coordinate the P700 reaction center chlorophyll(s) and the initial electron acceptor, A0. Oligonucleotide-mediated site-directed mutagenesis and chloroplast transformation of Chlamydomonas reinhardtii have been used to determine the importance of these conserved histidines in photosystem I reaction center biogenesis and function. It is demonstrated that these histidine residues are essential for stable accumulation of the photosystem I reaction center. Protein pulse-labeling shows that changing the histidine residues impairs a post-translational step in reaction center assembly. Photosystem I complexes from the mutants have been characterized by Electron Nuclear Double Resonance and Electron Spin Echo Envelope Modulation spectroscopy to determine the impact of any mutations on P700+. In all cases we determine that spectroscopic characteristics of P700+ remain unchanged. The implications of these results to current models of the photosystem I reaction center and related bacterial reaction centers are discussed.

Phosphatidylinositol-specific phospholipase C from Listeria monocytogenes contributes to intracellular survival and growth of Listeria innocua

Listeria monocytogenes is a facultative intracellular organism that is capable of replicating within macrophage and macrophage-like cells. The species secretes a phosphatidylinositol-specific phospholipase C (PI-PLC) encoded by the plcA gene. A plcA gene from L. monocytogenes was cloned downstream of a gram-positive promoter in the plasmid pWS2-2. To determine what effect plcA would have on intracellular survival when introduced into Listeria innocua, a species that does not growth intracellularly or contain plcA, transformation with the recombinant pWS2-2 plasmid was performed. Phospholipase C activity in Listeria innocua/pWS2-2 was confirmed on a brain heart infusion-phosphatidylinositol agar plate, whereas wild-type L. innocua did not produce PI-PLC activity. Intracellular growth of L. innocua/pWS2-2 was subsequently measured in the macrophage-like cell line J774 by Giemsa staining and viable count determinations at specific time points following infection. The J774 cells infected with wild-type L. innocua showed a falling viable count through 8 h postinfection. Although J774 cells infected with L. innocua/pWS2-2 also initially displayed reduced viable counts, the viable count rose after 6 h postinfection and increased further at 8 h postinfection before a subsequent decline again at 16 h postinfection. Giemsa staining revealed fewer than 6 bacteria in individual macrophage cells at 2 h postinfection, and yet approximately 15% of the J774 cells had 6 to 12 bacteria localized to one area of the macrophage cell after 6 h; moreover, electron micrographs showed that the L. innocua/pWS2-2 cells were replicating inside the phagosome of the host cell. Furthermore, Thoria Sol labeling demonstrated that lysosomes had fused with these phagosomes, and acridine orange staining revealed that the compartments were acidified. These results demonstrate that L. innocua cells transformed with the plasmid-borne plcA gene, and expressing functional PI-PLC, are able to grow intracellularly in what appear to be phagolysosomes, although between 3 and 6 h is needed for this to manifest itself. Intracellular growth specifically in L. innocua may be a secondary function associated with the plcA gene product. The addition of this one gene, plcA, to a species of Listeria that in the wild-type state does not replicate intracellularly apparently can now allow some of the bacteria to transiently multiply inside the phagosomes of host macrophage cells.

[Localized pulmonary edema in the right upper lobe--an important differential diagnostic hint for acute mitral insufficiency]

Differential diagnosis of unilateral alveolar pulmonary infiltration includes various possibilities. Acutely developing mitral insufficiency, often without any prior cardiac symptoms, may be the cause of pulmonary edema localized exclusively in the right upper lobe. This unusual and often misinterpreted radiologic presentation is brought to attention by two case reports.

Segmental differences in the effects of guanylin and Escherichia coli heat-stable enterotoxin on Cl- secretion in human gut

1. Mucosally added synthetic guanylin and Escherichia coli heat-stable enterotoxin (STa) increased short-circuit current (ISC) across isolated muscle-stripped human intestine in vitro. 2. Serosal bumetanide inhibited ISC responses indicating that guanylin and STa stimulate electrogenic chloride secretion. 3. ISC responses were markedly greater in the colon than in the jejunum. 4. Pretreatment with indomethacin did not significantly alter the effects of guanylin and STa. 5. Both peptides induced concentration-dependent increases in the cyclic GMP content of human intestinal mucosa in vitro; cyclic AMP levels remained unchanged. 6. In contrast to ISC responses, increases in cyclic GMP content induced by guanylin and STa were markedly greater in the jejunum than in the colon. 7. Sodium nitroprusside (SNP) but not human alpha-atrial natriuratic peptide (CDD/ANP(99-126)) increased chloride secretion in human intestine; both agents induced small increases in intestinal cyclic GMP content. 8. Guanylin, STa and the nitric oxide (NO) donor SNP increased electrogenic chloride secretion across human intestinal mucosa in vitro by stimulation of cyclic GMP. The discrepancy between the effects on chloride secretion and intracellular cyclic GMP content suggest different cellular action sites of guanylin and STa in human small and large intestine.

Identification of a promoter region for mxaF (moxF) from the type I methanotroph, Methylobacter albus BG8

A fragment of Methylobacter albus BG8 DNA containing mxaF (moxF), the gene encoding the alpha subunit of methanol dehydrogenase, was previously cloned using a fragment of mxaF from Methylobacterium extorquens AM1 as a probe (Stephens et al., J. Bacteriol. (1988) 170, 2063-2069). In this study we identified the 5' portion of mxaF of M. albus BG8 and sequenced a 1.7-kb region containing the 5' portion of mxaF and 1.5 kb of upstream DNA. The deduced N-terminal amino acid sequence of mxaF was found to have very high similarity to the previously sequenced mxaF genes. The region directly upstream of mxaF was cloned into a promoter probe vector (pGD500), and promoter activity was demonstrated when the fragment was present in the correct orientation with relation to the reporter gene (lacZ). Using reverse transcriptase, the transcription initiation start site was determined, which was separated from the translation initiation site by 190 nucleotides.

Listeria monocytogenes infection enhances transcription factor NF-kappa B in P388D1 macrophage-like cells

In the present study, we investigated the effect of Listeria monocytogenes infection on the cellular level of the transcription factors NF-kappa B, AP-1, and NF-IL6 in the macrophage-like cell line P388D1 by using electrophoretic mobility shift assays. Infection with L. monocytogenes enhanced the formation of two NF-kappa B-like DNA-protein complexes, C1 and C2, whereas the concentration of AP-1 and NF-IL6 complexes remained unaffected. In supershift assays using NF-kappa B-specific antibodies, complex C2 was identified to be a p50 homodimer (KBF1) and complex C1 was identified as a p50/p65 heterodimer. Both complexes were formed within 10 min after addition of the bacteria. Since the synthesis of tumor necrosis factor alpha and interleukin-1 occurs at later times, these cytokines cannot be the mediators of enhanced NF-kappa B formation. Infection experiments with different nonhemolytic mutants of L. monocytogenes and the use of the phagocytosis inhibitor cytochalasin B suggest that events prior to invasion and escape of the bacteria from the phagosome into the cytoplasm enhance the nuclear transport of p50/p65 NF-kappa B components.

Enterochromaffin cells of the digestive system: cellular source of guanylin, a guanylate cyclase-activating peptide

Guanylin, a bioactive peptide, has recently been isolated from the intestine; this peptide activates intestinal guanylate cyclase (i.e., guanylate cyclase C) and thus is potentially involved in the regulation of water/electrolyte transport in the gastrointestinal mucosa. As yet, the cells involved in synthesis, storage, or secretion of guanylin have not been identified by immunocytochemistry. We raised antisera against guanylin and investigated the entire gastrointestinal tract of guinea pigs by light and electron microscopical immunocytochemistry. Extracts of various intestinal segments and plasma analyzed on a Western blot revealed a peptide band corresponding to the molecular mass of guanylin. Localization studies in the entire digestive tract showed that guanylin is exclusively confined to enterochromaffin (EC) cells. Remarkably, most EC cells contacted the gut lumen by cell processes that were highly immunoreactive for guanylin. In addition to the well known secretion in an endocrine fashion, EC cells by circumstantial evidence may release guanylin into the gut lumen to activate guanylate cyclase C that is immediately located on the brush border of adjacent enterocytes. The unique localization of guanylin in EC cells may indicate that these cells are involved in the regulation of fluid secretion in the gastrointestinal mucous membrane.

[Fatal outcome of pneumocystis-carinii pneumonia under low-dose methotrexate and prednisone therapy for chronic rheumatoid arthritis. Case report and literature review]

New therapeutic schemes have been proposed recently for treatment of rheumatoid arthritis. Among these, methotrexate at low doses is recommended as basic therapy, already shortly after the diagnosis is established. We report on a 68-year-old female with rheumatoid arthritis who developed bilateral pneumocystis-carinii pneumonia with a lethal course and bilateral sinusitis maxillaris with candida lusitaniae. Various opportunistic infections have been described in the literature after low-dose methotrexate. It is our view that the use of methotrexate in rheumatoid arthritis should still be considered cautiously until further data on the risk-benefit ratio of long-term use become available.

Radioimmunoassay for circulating human guanylin

A highly specific and sensitive radioimmunoassay for circulating human guanylin (guanylin-22-115) has been developed. Antibodies were raised against the amino-terminus (positions 4-16) of the peptide. Western blot analysis confirmed that the antibody selected for radioimmunoassay recognizes circulating high molecular weight (10.3 kDa) guanylin. Extraction and purification of guanylin from blood hemofiltrate and from blood plasma showed that circulating guanylin is detectable in corresponding amounts by the radioimmunoassay and by a specific bioassay. In 30 healthy subjects, the mean plasma concentration of immunoreactive (IR) guanylin was 42 +/- 3 fmol/ml. In 22 patients with chronic renal insufficiency, the concentrations of IR-guanylin were significantly enhanced (1,074 +/- 24 fmol/ml), indicating that kidneys metabolize and/or eliminate the circulating hormone.

Induction of cytokines in phagocytic mammalian cells infected with virulent and avirulent Listeria strains

The present paper analyzes the cytokine response of mouse macrophages during infection by Listeria monocytogenes. The use of different mutants of L. monocytogenes impaired in various steps of the infection process allowed us to dissect the cytokine response. Cytokine mRNA expression was detected by PCR-assisted amplification of RNA extracted from macrophages after infection with different Listeria strains. An increase in the amount of mRNA for tumor necrosis factor alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha), IL-1 beta, and IL-6 was detected in P388D1 macrophages infected with L. monocytogenes at 4 h postinfection. Interestingly, only hemolytic strains of L. monocytogenes were able to induce IL-1 alpha, IL-6, and TNF-alpha mRNA. This indicated that the induction of these cytokine mRNAs requires entry of the listeriae into the host cell cytoplasm. In contrast, IL-1 beta was also induced by infection with nonhemolytic mutants of L. monocytogenes which remain entrapped within the phagosome. The levels of TNF, IL-1 alpha, and IL-6 found in the supernatants of Listeria-infected P388D1 macrophages generally correlated well with the induction of the respective mRNAs, but it became obvious that cytokine activity is also regulated through posttranscriptional mechanisms. In vitro induction of the cytokines IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha was also observed by infection of bone-marrow-derived macrophages with L. monocytogenes.