Purification and biochemical characterization of the EcaI DNA methyltransferase.

The EcaI GGTNACC-specific DNA-adenine modification methyltransferase has been purified to apparent homogeneity. The active form of the DNA methyltransferase is a single polypeptide. The enzyme has a pH optimum at pH 8.0 and a temperature optimum at 25 degrees C. EcaI DNA methyltransferase transfers one methyl group to the adenine of the recognition site in a single binding event. The Km was 170 nM for DNA and 1.8 microM for the methyl donor S-adenosylmethionine. Methylated DNA is a competitive inhibitor with respect to DNA (Ki = 3.5 nM). The other product of the DNA-methylation reaction, S-adenosylhomocysteine was found to be a competitive inhibitor with respect to S-adenosylmethionine (Ki = 2.7 microM). The S-adenosylmethionine analog sinefungin was shown to be a very strong inhibitor (Ki = 3.5 nM) of the DNA methyltransferase reaction.


Characterization and molecular cloning of a flavoprotein catalyzing the synthesis of phytofluene and zeta-carotene in Capsicum chromoplasts.

In plants, zeta-carotene is the first visible carotenoid formed in the biosynthetic pathway through the following two-step desaturation reaction: phytoene-->phytofluene--> zeta-carotene. Using Capsicum annuum chromoplast membranes and the reconstitution system previously described [Camara, B., Bardat, F. & Monéger, R. (1982) Eur. J. Biochem. 127, 255-258], we have attempted to purify the desaturase(s) catalyzing these reactions. The two activities were coincidental during all the purification procedures. Only a single polypeptide with 56 +/- 2 kDa was detected by SDS/PAGE of all active fractions. The enzyme contained protein-bound FAD. Antibodies raised against the purified polypeptide selectively precipitated the phytoene and the phytofluene desaturase activities, thus demonstrating that the enzyme is a bifunctional flavoprotein. The antibodies were used to isolate a full-length cDNA clone from which was deduced the primary structure of the desaturase which contains a characteristic dinucleotide-binding site. Overexpression of the cDNA in Escherichia coli allowed the production of a recombinant desaturase which had all the properties of the chromoplast desaturase. The phytoene/phytofluene desaturase mRNA levels were extremely low in green fruits and increased slightly before detectable carotenoid synthesis and remained constant throughout ripening. However, the desaturase activity and protein levels were found to increase significantly during the chloroplast to chromoplast transition in C. annuum fruits.


Substrate specificity of small-intestinal lactase. Assessment of the role of the substrate hydroxyl groups.

Lactase-phlorizin hydrolase is a disaccharidase present in the small intestine of mammals. This enzyme has two active sites, one being responsible for the hydrolysis of lactose. Lactase activity is thought to be selective towards glycosides with a hydrophilic aglycon. In this work, we report a systematic study on the importance of each hydroxyl group in the substrate molecule for lactase activity. For this purpose, all of the monodeoxy derivatives of methyl beta-lactoside and other lactose analogues are studied as lactase substrates. With respect to the galactose moiety, it is shown here that HO-3' and HO-2' are necessary for hydrolysis of the substrates by lactase. Using these chemically modified substrates, it has been confirmed that lactase does not behave as a typical beta-galactosidase, since it does not show an absolute selectivity with respect to substitution and stereochemistry at C4' in the galactose moiety of the substrate. However, the glucose moiety, in particular the HO-6, appears to be important for substrate hydrolysis, although none of the hydroxyl groups seemed to be essential. In order to differentiate both activities of the enzyme, a new assay for the phlorizin-hydrolase activity has also been developed.


Fast kinetics studies of Escherichia coli electrotransformation.

Direct gene transfer is achieved in Escherichia coli by use of square wave electric pulsing. As observed by video monitoring, the field pulse causes bacteria to orientate parallel to the field lines. Rapid kinetic turbidity changes indicate that this process happens quickly. In these circumstances, and in pulsing conditions prone to inducing transformation, only caps are affected by the field. Considerable cytoplasmic ion leakage occurs during the pulse, affecting the interfacial ionic concentration. The pulsing-buffer osmolarity has to be close to that used with protoplasts. Contact between the plasmid and the bacteria can be very short before the pulse but must be present during the pulse. The plasmid remains accessible to externally added DNases up to 5 days after the pulse, suggesting that the transfer step is slow. Electric-field-mediated transfer can be described in two steps: the anchoring process during the pulse, followed by the crossing of the membrane.


Effect of anisotonic cell-volume modulation on glutathione-S-conjugate release, t-butylhydroperoxide metabolism and the pentose-phosphate shunt in perfused rat liver.

1. Addition of 1-chloro-2,4-dinitrobenzene to isolated perfused rat liver results in the rapid formation of its glutathione-S-conjugate [S-(2,4-dinitrophenyl)glutathione], which is released into both, bile and effluent perfusate. Anisotonic perfusion did not affect total S-conjugate formation, but release of the S-conjugate into the perfusate was increased (decreased) following hypertonic (hypotonic) exposure at the expense of excretion into bile. Stimulation of S-conjugate release into the perfusate following hypertonic exposure paralleled the time course of volume-regulatory net K+ uptake. 2. Basal steady-state release of oxidized glutathione (GSSG) into bile was 1.30 +/- 0.12 nmol.g-1.min-1 (n = 18) during normotonic (305 mOsmol/l) perfusion and was 3.8 +/- 0.3 nmol.g-1.min-1 in the presence of t-butylhydroperoxide (50 mumol/l). Hypotonic exposure (225 mOsmol/1) lowered both, basal and t-butylhydroperoxide (50 mumol/l)-stimulated GSSG release into bile by 35% and 20%, respectively, whereas hypertonic exposure (385 mOsmol/l) increased. Anisotonic exposure was without effect on t-butylhydroperoxide removal by the liver. GSSG release into bile also decreased by 33% upon liver-cell swelling due to addition of glutamine plus glycine (2 mmol/l, each). 3. Hypotonic exposure led to a persistent stimulation 14CO2 production from [1-14C]glucose by about 80%, whereas 14CO2 production from [6-14C]glucose increased by only 10%. Conversely, hypertonic exposure inhibited 14CO2 production from [1-14C]glucose by about 40%, whereas 14CO2 production from [6-14C]glucose was unaffected. The effect of anisotonicity on 14CO2 production from [1-14C]glucose was also observed in presence of t-butylhydroperoxide (50 mumol/l), which increased 14CO2 production from [1-14C]glucose by about 40%. 4. t-Butylhydroperoxide (50 mumol/l) was without significant effect on volume-regulatory K+ fluxes following exposure to hypotonic (225 mOsmol/l) or hypertonic (385 mOsmol/l) perfusate. Lactate dehydrogenase release from perfused rat liver under the influence of t-butylhydroperoxide was increased by hypertonic exposure compared to hypotonic perfusions. 5. The data suggest that hypotonic cell swelling stimulates flux through the pentose-phosphate pathway and diminishes loss of GSSG under conditions of mild oxidative stress. Hypotonically swollen cells are less prone to hydroperoxide-induced lactate dehydrogenase release than hypertonically shrunken cells. Hypertonic cell shrinkage stimulates the excretion of glutathione-S-conjugates into the sinusoidal circulation at the expense of biliary secretion.


Regulation of insulin-like-growth-factor-II gene expression in rat liver cells.

The rat insulin-like-growth-factor-(IGF)-II gene is expressed at high levels during embryonic and fetal life and at low levels in adult animals. To study the regulation of IGF-II gene expression, we analyzed the synthesis and localization of the IGF-II transcripts in cultured rat liver cells either expressing (BRL3A cells) or not expressing (BRL30E and FAO cells) the IGF-II mRNA. The IGF-II gene is transcribed at a similar rate in expressing and non-expressing cells, whereas its nuclear and cytoplasmic RNA levels are diversely distributed in the cells. IGF-II RNA is more abundant in the cytoplasmic than in the nuclear RNA fraction of BRL3A cells and is present in the nucleus but not in the cytoplasm of the FAO cells. However, both precursor and mature IGF-II nuclear RNA levels are reduced in FAO cells. Our data indicate that the IGF-II gene expression is regulated by mechanisms affecting the subcellular distribution and the abundance of the transcripts.


Redox properties of the iron-sulfur clusters in activated Fe-hydrogenase from Desulfovibrio vulgaris (Hildenborough).

The periplasmic Fe-hydrogenase from Desulfovibrio vulgaris (Hildenborough) contains three iron-sulfur prosthetic groups: two putative electron transferring [4Fe-4S] ferredoxin-like cubanes (two F-clusters), and one putative Fe/S supercluster redox catalyst (one H-cluster). Combined elemental analysis by proton-induced X-ray emission, inductively coupled plasma mass spectrometry, instrumental neutron activation analysis, atomic absorption spectroscopy and colorimetry establishes that elements with Z > 21 (except for 12-15 Fe) are present in 0.001-0.1 mol/mol quantities, not correlating with activity. Isoelectric focussing reveals the existence of multiple charge conformers with pI in the range 5.7-6.4. Repeated re-chromatography results in small amounts of enzyme of very high H2-production activity determined under standardized conditions (approximately 7000 U/mg). The enzyme exists in two different catalytic forms: as isolated the protein is 'resting' and O2-insensitive; upon reduction the protein becomes active and O2-sensitive. EPR-monitored redox titrations have been carried out of both the resting and the activated enzyme. In the course of a reductive titration, the resting protein becomes activated and begins to produce molecular hydrogen at the expense of reduced titrant. Therefore, equilibrium potentials are undefined, and previously reported apparent Em and n values [Patil, D. S., Moura, J. J. G., He, S. H., Teixeira, M, Prickril, B. C., DerVartanian, D. V., Peck, H. D. Jr, LeGall, J. & Huynh, B.-H. (1988) J. Biol. Chem. 263, 18,732-18,738] are not thermodynamic quantities. In the activated enzyme an S = 1/2 signal (g = 2.11, 2.05, 2.00; 0.4 spin/protein molecule), attributed to the oxidized H cluster, exhibits a single reduction potential, Em,7 = -307 mV, just above the onset potential of H2 production. The midpoint potential of the two F clusters (2.0 spins/protein molecule) has been determined either by titrating active enzyme with the H2/H+ couple (E,m = -330 mV) or by dithionite-titrating a recombinant protein that lacks the H-cluster active site (Em,7.5 = -340 mV). There is no significant redox interaction between the two F clusters (n approximately 1).


Relationship between the major protein kinase C substrates acidic 80-kDa protein-kinase-C substrate (80K) and myristoylated alanine-rich C-kinase substrate (MARCKS). Members of a gene family or equivalent genes in different species.

Two major protein-kinase-C (PKC) substrates have been described in the literature; an 87-kDa bovine and human PKC substrate, called MARCKS, and an acidic 80-kDa PKC substrate, isolated from rat brain and Swiss 3T3 cells, termed 80K. Since there is only 66-74% sequence similarity between MARCKS and 80K, we have further investigated their relationship in this study. Southern-blot experiments with gene-specific probes demonstrated the presence of the 80K, but not MARCKS, gene in the mouse genome. Furthermore, polymerase-chain-reaction (PCR) analyses using three pairs of primers that specifically recognise either 80K, MARCKS or conserved sequences of both genes, revealed the presence of only the 80K gene in the mouse and rat genomes and only the MARCKS gene in the bovine and human genomes with mRNA expression in the corresponding brain tissues. Northern-blot analysis of a variety of tissues indicated that both 80K and MARCKS have similar patterns of expression. Most components of signal-transduction pathways are present in multiple molecular isoforms as members of a gene family. In contrast, the findings presented in this study indicate that rodent 80K and bovine and human MARCKS are not distinct members of a gene family, but represent the equivalent substrates in different species.


Synovial protein kinase C and its apparent insensitivity to interleukin-1.

Lapine synovial fibroblasts produce prostaglandin E2 (PGE2) and neutral metalloproteinases in response to phorbol 12-myristate 13-acetate (PMA), human recombinant interleukin-1 (hrIL-1) and, in an autocrine fashion, in response to partially purified preparations of their own cytokines known as cell-activating factors (CAF). Here we have examined the possible role of protein kinase C (PKC) in these responses. Whereas the 80-kDa substrate for PKC could not be detected in synovial fibroblasts, these cells contained a 35-kDa protein which fulfilled the criteria for qualifying as a specific substrate of PKC. Translocation assays based upon phosphorylation of the 35-kDa protein and Western blotting techniques allowed the movement of PKC from the cytosolic to the particulate fraction in response to PMA and CAF to be detected but not in response to 4 alpha-PMA or hrIL-1. Inhibitors of PKC suppressed synovial activation by PMA, partially blocked activation by CAF but had no effect on activation by hrIL-1. There thus appear to be PKC-dependent and PKC-independent routes to synovial cell activation. Our data suggest that IL-1 uses the latter, while CAF contains cytokines which utilize both routes.


Phenotypic transformation of normal rat kidney cells by transforming growth factor beta is not paralleled by enhanced production of a platelet-derived growth factor.

Phenotypic transformation of normal rat kidney (NRK) cells requires the concerted action of multiple polypeptide growth factors. Serum-deprived NRK cells cultured in the presence of epidermal growth factor (EGF) become density-inhibited at confluence, but they can be restimulated by a number of defined polypeptide growth factors, resulting in phenotypic cellular transformation. Kinetic data show that restimulation by transforming growth factor beta (TGF-beta) and retinoic acid is delayed when compared to induction by platelet-derived growth factor (PDGF), indicating that both TGF beta and retinoic acid may exert their growth-stimulating action by an indirect mechanism. Northern blot analysis shows that NRK cells express the genes for various polypeptide growth factors, including TGF beta 1, PDGF A-chain and basic fibroblast growth factor, but that the levels of expression are not affected by TGF beta or retinoic acid treatment. NRK cells also secrete low amounts of a PDGF-like growth factor into their extracellular medium, but the levels of secretion are insufficient to induce mitogenic stimulation and are unaffected by agents inducing phenotypic transformation. In combination with studies on the effects of anti-PDGF antibodies, it is concluded that phenotypic transformation of NRK cells by TGF beta and retinoic acid is not the result of enhanced production of a PDGF-like growth factor.


Regulatory protein phosphorylation of phosphoenolpyruvate carboxylase in the facultative crassulacean-acid-metabolism plant Mesembryanthemum crystallinum L.

Phosphoenolpyruvate PyrP carboxylase (PyrPC) and PyrPC kinase were copurified from dark-adapted leaves of the common ice plant Mesembryanthemum crystallinum L. with crassulacean-acid metabolism (CAM). Purification by (NH4)2SO4 fractionation, chromatography on Fractogel-DEAE and hydroxylapatite resulted in a PyrPC preparation with a specific activity of 23-25 U/mg protein and a protein kinase activity of 255 mumol Pi.mol-1 PyrPC.s-1. After in vitro phosphorylation, the most prominently phosphorylated polypeptide was identified as PyrPC by immunoblotting and sequencing. Phosphorylation of PyrPC in vitro by incubation with 400 microM MgATP decreased its sensitivity towards malate. When purified in the absence of the protease inhibitor chymostatin, PyrPC lost an N-terminal sequence of 128 amino acids. Although the carboxylation reaction was unaffected, the truncated PyrPC could neither be phosphorylated in vitro nor inhibited by malate. This result and data obtained by limited proteolysis concur with the hypothesis [Jiao, J.A. & Chollet, R. (1989) Arch. Biochem. Biophys. 283, 300-305] that Ser11 is the phosphorylation site of the CAM PyrPC of M. crystallinum. At pH 7.0, the Km for ATP of the protein kinase was 25 microM; phosphorylation of PyrPC was maximal after 30 min at pH 7.0. The kinase showed also activity with histone III-S but not with dephosphorylated casein. It was inhibited by malate. The results show, that reversible protein phosphorylation is an important factor in the regulation of PyrPC in the facultative CAM plant M. crystallinum, similar to C4 and constitutive CAM plants.


Survey of Escherichia coli septicemia over a six-year period.

Escherichia coli was the most frequent species isolated from blood cultures in the Hospital Covadonga of Oviedo (Spain) over a six-year period (474 episodes, 15.3% of the total septicemias and 2.7 episodes per 1,000 patients). Escherichia coli strains were susceptible in greater than 95% of episodes to cefoxitin, cefotaxime, gentamicin, tobramycin and amikacin. In a series of 72 episodes, microbiological features and host factors were studied. No endemic stains were found. Type 1 fimbria was detected in 73.6% of strains and P-fimbriae in 12.5%, without correlation between P-fimbria and urinary infection; 84.7% of the strains were resistant to decomplement human serum; 61.1% produced aerobactin and 20.8% were hemolytic. Factors such as age, hospital location, metastatic focus and surgical treatment were significantly correlated with morbidity and mortality. The global mortality rate was 18%, and in 8.3% of cases was directly associated with septicemia.


Cefuroxime and cefuroxime axetil versus amoxicillin plus clavulanic acid in the treatment of lower respiratory tract infections.

In a large multinational study, the clinical and bacteriological efficacy of intravenous cefuroxime 750 mg t.i.d. followed by oral cefuroxime axetil 500 mg b.i.d. was compared to that of amoxicillin plus clavulanic acid (CA) administered as 1.2 g intravenously t.i.d. followed by 625 mg orally t.i.d. in the treatment of lower respiratory tract infections in hospitalised patients. A total of 512 patients were entered (256 in each treatment group). All were suffering from pneumonia or acute exacerbations of chronic bronchitis or bronchiectasis and required initial parenteral antibiotic therapy. Parenteral therapy lasted 48 to 72 h and was followed by five days of oral therapy. The clinical responses in the two treatment groups were very similar: 223 of 256 (87.1%) patients were cured or improved with cefuroxime/cefuroxime axetil compared to 220 of 256 (85.9%) with amoxicillin/CA. Positive pre-treatment sputum samples were obtained from 44% of the patients. Clearance rates obtained were again similar: 72.8% with cefuroxime/cefuroxime axetil and 70% with amoxicillin/CA. Ten percent of the isolates were beta-lactamase producers, similar numbers of which were cleared in both groups. Both regimens were generally well tolerated, with only 5% of patients treated with the cefuroxime regimen and 4.3% of patients treated with amoxicillin/CA experiencing drug-related adverse events. Cefuroxime/cefuroxime axetil "follow-on" therapy produces clinical and bacteriological efficacy equivalent to that of amoxicillin/CA, with the advantage of twice daily oral administration.


Cotrimoxazole therapy of Toxoplasma gondii encephalitis in AIDS patients.

Twenty-four consecutive HIV-positive patients affected by Toxoplasma gondii encephalitis received trimethoprim-sulfamethoxazole (cotrimoxazole) as acute-phase treatment. Two dosage regimens of cotrimoxazole were used: 40 mg/kg/day (12 patients) or 120 mg/kg/day (12 patients) of total compound (trimethoprim plus sulfamethoxazole). Clinical and radiological responses to treatment were evaluated, and the product-limit method for survival data analysis was used. Eighteen of 24 patients showed both a clinical and radiological response (75% response rate). There were no differences in response rates between patients receiving the two dosage regimens of cotrimoxazole. Adverse reaction consisted of leukopenia (two cases) and skin rash (three cases) which led to the discontinuation of the drug in one case. These results suggest that a randomized, controlled clinical trial should be carried out comparing cotrimoxazole versus sulfadiazine-pyrimethamine in AIDS patients with Toxoplasma gondii encephalitis.


Prevalence of Chlamydia pneumoniae antibodies in Hungary.

Investigation of Chlamydia pneumoniae (TWAR) antibodies in paired sera of 120 patients with various respiratory diseases revealed a prevalence of 4.2% of IgG seroconversion. IgG antibody without seroconversion was found in 83.3%. Sera of ten patients showed titers as high as 512-1024 or above. Children with no respiratory disease and blood donors in Budapest had specific IgG in 46.5% and 75.2% respectively. Prevalence of IgG antibody in children from the rural areas of Hungary was about 50% lower than in children in the capital. The high prevalence of persistent IgG, indicating earlier infection, suggests that Chlamydia pneumoniae infection may be endemic in Budapest. The small number of the serologically confirmed acute infections in hospitalized patients with pneumonia leads to the conclusion that the majority of patients with chlamydial pneumonia responds to the therapeutic regimen administered by the general practitioner and referral to hospital rarely becomes necessary.


Effects of fluconazole on the sterol and carbohydrate composition of four species of Candida.

The effects of fluconazole, a bis-triazole antifungal agent, on the sterol and carbohydrate composition of Candida albicans, Candida tropicalis, Candida krusei and Candida parapsilosis were investigated. Exposure of Candida species to fluconazole resulted in a profound depletion of ergosterol with a corresponding increase in lanosterol content versus control cells. Carbohydrate analysis revealed a significant increase in chitin and either a decrease (Candida albicans, Candida tropicalis and Candida parapsilosis) or an increase (Candida krusei) in glucan content in fluconazole-treated cells. The decreased ergosterol and increased lanosterol content is consistent with 14-alpha-demethylase inhibition by fluconazole. The increase in cell wall chitin is most likely due to deregulation of chitin synthesis secondary to ergosterol depletion in the cell membrane. Because chitin, glucan and ergosterol are critical components of the fungal cell, perturbation of the production and localization of these components by fluconazole is likely to contribute to the selective toxicity of this compound to Candida species and other fungi.


Spleen abscess caused by Eikenella corrodens.

A case is reported of splenic abscess due to Eikenella corrodens, a gram-negative rod which is found as part of normal flora in human mucous surfaces. A 64-year-old man presented with fever, chills, anorexia and abdominal pain. Abdominal ultrasound examination showed a perisplenic fluid collection which was considered to be either blood or a subcapsular spleen abscess. The presence of a splenic abscess was later confirmed during surgery and a splenectomy was performed. Splenic purulent material and blood cultures yielded Eikenella corrodens. The patient received cefotaxime for 19 days and was discharged asymptomatic.


Monitoring of antibiotic resistance in shigellae isolated in The Netherlands 1984-1989.

During surveillance of antimicrobial resistance in Shigella strains isolated in the Netherlands from 1984 to 1989 and forwarded to the National Institute of Public Health and Environmental Protection for typing, sensitivity to twelve antimicrobial agents was assessed. High rates of resistance to the older drugs of choice in treating shigellosis were found, i.e. ampicillin and trimethoprim-sulfamethoxazole. Ampicillin resistance varied from 33 to 53% among Shigella flexneri strains and from 10 to 17% among Shigella sonnei strains. Trimethoprim and trimethoprim-sulfamethoxazole resistance increased from 8% to about 25% among Shigella flexneri and from 16 to 46% among Shigella sonnei isolates. All strains were susceptible to the newer quinolones, but five strains resistant to nalidixic acid showed decreased susceptibility to norfloxacin. Approximately 10% of the isolates were resistant to the combination of ampicillin, trimethoprim and sulfamethoxazole.


Retrospective study to determine the diagnostic value of the Widal test in a non-endemic country.

The purpose of this study was to determine the usefulness of the Widal test in the diagnosis of typhoid fever. Data were obtained by retrospective analysis of 311 Widal requests covering a six-year period. Nine cases of typhoid infection were diagnosed culturally. Of these, only three patients had samples for serological examination, all giving indicative titres. Of the 274 evaluated sera, 26 showed significant agglutinating titres; 23 of them were false positive. These results show that routine use of the Widal test is of limited value and should only be used for patients in whom repeated cultures remain negative.


Differential effects of bismuth and salicylate salts on the antibiotic susceptibility of Pseudomonas aeruginosa.

The influence of salicylate or bismuth salts on antibiotic action against Pseudomonas aeruginosa was assessed in broth cultures. Sodium salicylate (2.5 mM) had no significant effect on the activity of any antibiotic tested. In contrast, bismuth compounds (0.5 mM) produced a significant change in the inhibitory activity of several antibiotics against all strains. Bismuth salts reduced imipenem activity by up to 20-fold, enhanced gentamicin or amikacin activity three to five-fold, and enhanced cefpirome or cefepime activity by as much as 10-fold against antibiotic-sensitive and resistant strains. Bismuth salts had little effect on cefoperazone, ceftazidime, or mezlocillin activity. Combining bismuth salts with aminoglycosides or fourth-generation cephalosporin antibiotics may help to combat the growing problem of resistant Pseudomonas aeruginosa.


Comparison of a new commercial enzyme immunoassay for rapid detection of respiratory syncytial virus.

Two rapid methods for detection of respiratory syncytial virus in respiratory specimens were compared: direct immunofluorescence assay (DFA) with monoclonal antibody and an enzyme immunoassay (EIA) (Test-Pack RSV). Ninety-five nasopharyngeal washings and aspirates from 51 children were examined; the patients were hospitalized during a winter outbreak of RSV infection in the first trimester of 1990. A total of 41.0% and 56.8% of these samples were positive by EIA and DFA respectively. Considering only the 51 specimens collected at the onset of illness, EIA detected 72.5% positive samples and DFA detected 78.4%. In comparison with DFA, EIA was 92.5% sensitive and 100% specific for the acute phase of illness. When all the samples were taken into account, specificity was maintained but sensitivity fell to 72.2%. The results show that both methods are useful during the acute phase of the illness, when the viral load is important. However, later on in the course of the infection DFA appears to be more sensitive than EIA.


Evaluation of the E test in testing susceptibility of Pseudomonas aeruginosa to tobramycin.

The E test, a new technique for measuring MICs of antimicrobial agents with the ease of disc diffusion tests, was evaluated in testing the susceptibility of 94 clinical isolates of Pseudomonas aeruginosa to tobramycin. The use of the E test was found acceptable; 93% of the MIC results were within one log2 dilution step and 100% were within two log2 dilution steps when the MICs obtained by the E test were compared to those obtained by the conventional agar dilution method. When the E test was compared to the broth microdilution method the corresponding figures were 84% and 100%, respectively.


Antibacterial activity of the investigational oral and parenteral cephalosporin BK-218.

BK-218 is a novel cephalosporin with a dual route of administration and spectrum of activity most similar to that of second-generation cephalosporins. BK-218 was active against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis but strains resistant to penicillins had higher MICs. BK-218 had greater activity (8-fold) than cefuroxime or cefaclor against oxacillin-susceptible Staphylococcus spp. Moderate BK-218 activity was observed against Neisseria gonorrhoeae and commonly isolated Enterobacteriaceae such as Escherichia coli (MIC90, 1 mg/l), Klebsiella spp. (MIC90, 2 mg/l), and Proteus mirabilis (MIC90, 2 mg/l). The following organisms were generally BK-218-resistant (MIC90, greater than 16 mg/l): Bacteroides fragilis, Pseudomonas spp., Acinetobacter spp., Xanthomonas maltophilia, Citrobacter spp., Enterobacter spp., indole-positive Proteus, Serratia spp., enterococci and oxacillin-resistant staphylococci.


Fungal infections in cancer patients: an international autopsy survey.

In an attempt to estimate the frequency of fungal infections among cancer patients, a survey of autopsy examinations was conducted in multiple institutions in Europe, Japan and Canada. Fungal infections were identified most often in leukemic patients and transplant recipients (25% each). Fifty-eight percent of fungal infections were caused by Candida spp. and 30% by Aspergillus spp. There was considerable variability in the frequency of fungal infections in different countries. Nevertheless, this study clearly demonstrates that fungal infections represent a common complication in cancer patients, especially in patients with leukemia.


Impact of the changing epidemiology of fungal infections in the 1990s.

The increase in fungal infections over the past decade is striking. This is particularly true for hospitalized patients where the rate of candidal bloodstream infection has increased by as much as 487% over the decade of the 1980s. This increase in fungal infections is accompanied by a significant excess mortality and excess length of stay in hospital. The emergence of "new" fungal pathogens such as Candida krusei, Torulopsis glabrata, Fusarium and Trichosporon beigelii is now recognized as a significant problem in many patient populations. The documentation of nosocomial transmission of fungal pathogens and the recognition of resistance to both new and established anti-fungal agents poses a significant problem entering the 1990s. Continued effort is needed to develop new and better therapeutic agents and more effective strategies for prophylaxis of endogenous infections and prevention of transmission within the hospital setting.


Antibiotic sensitivity of the Bacteroides fragilis group in Europe. European Study Group.

Rates of resistance to 12 antibiotics were determined for 1,289 isolates of Bacteroides fragilis group submitted in 1988-1989 by 22 laboratories in 15 European countries. There was no resistance to metronidazole (breakpoint 8 mg/l) and only one isolate was resistant to chloramphenicol (breakpoint 8 mg/l). Resistance was uncommon for imipenem (0.3% at greater than 4 mg/l), amoxicillin/clavulanate (1% at greater than 8 mg/l), cefoxitin (3% at greater than 32 mg/l), mezlocillin (6% at greater than 64 mg/l) and clindamycin (9% at greater than 4 mg/l). Resistance was the rule for ampicillin (93% at greater than 4 mg/l), ciprofloxacin (56% at greater than 4 mg/l) and tetracycline (64% at greater than 4 mg/l). Bacteroides fragilis, the commonest species, was generally the most sensitive: resistance of this organism was uncommon for cefotetan (4% at greater than 32 mg/l) and ceftazidime (12% at greater than 32 mg/l) to which the other species were more often resistant. There were small but significant differences between laboratories and countries for many of the antibiotics. Regionally the most striking differences were for clindamycin where resistance in Bacteroides fragilis was most common in the South and for tetracycline where resistance in Bacteroides fragilis, Bacteroides thetaiotaomicron and Bacteroides uniformis was least common in the North.


Use of molecular methods to characterize Moraxella catarrhalis strains in a suspected outbreak of nosocomial infection.

Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of whole cell protein, immunoblotting with normal human serum and restriction endonuclease analysis using Taq I enzyme were applied to 38 clinically significant isolates of Moraxella (Branhamella) catarrhalis obtained during a suspected outbreak of nosocomial infection. Each of 18 strains had individual profiles by at least two of the three methods (unique strains). The remaining 20 strains were assigned to five groups (A-E) on the basis of similarity by at least two of the three methods. Isolates within groups A, D and E were homologous by all three methods. Immunoblot groups B and C had two distinct whole cell protein profiles (B1 and B2) but indistinguishable restriction endonuclease profiles (group B/C). This emphasizes the need to use more than one technique in characterizing strains from suspected outbreaks of nosocomial infection. Grouped strains were more likely to originate from the same hospital ward than unique strains and were associated with a significantly longer median time from patient admission to strain isolation (14 versus 3.5 days, p less than 0.005). Furthermore, the beta-lactamase activity was homologous within the groups. The results suggest that nosocomial infection involving several distinct Moraxella catarrhalis strains persisted over a period of months, involving at least 20 patients on three different wards. Such infection is probably common in wards harbouring suitably predisposed patients. The mode of transmission remains to be elucidated, but the above three techniques possess sufficient reproducibility and discriminatory ability to constitute suitable investigative tools.


Characterization of cell-bound papain-soluble beta-lactamases in BRO-1 and BRO-2 producing strains of Moraxella (Branhamella) catarrhalis and Moraxella nonliquefaciens.

In Moraxella (Branhamella) catarrhalis and Moraxella nonliquefaciens strains isolated from clinical specimens in the south of Sweden two variants of beta-lactamase were distinguished by isoelectric focusing (IEF). The BRO-1 (Ravasio type) enzyme was the most common in Branhamella catarrhalis, constituting about 90% of the beta-lactamase found in this species, while the BRO-2 enzyme (1908 type) was as common as BRO-1 in Moraxella nonliquefaciens. The determinants mediating the production of BRO-1 and BRO-2 were both transferable by conjugation. Cell-bound beta-lactamase from reference strains producing BRO-1 and BRO-2 could be solubilized by papain digestion. The isoelectric point of the solubilized enzymes differed distinctly between BRO-1 (pI 6.5) and BRO-2 (pI 6.9). The molecular species of BRO-1 and BRO-2 released by papain digestion were purified by affinity chromatography with phenylboronic acid agarose gel. They had identical molecular weights of approximately 28,000. Their kinetic constants were indistinguishable for a number of substrates and beta-lactamase inhibitors.


Use of a urea breath test versus invasive methods to determine the prevalence of Helicobacter pylori in Zaire.

The prevalence of Helicobacter pylori infection in Zaire was determined by means of a [14C] urea breath test in 133 asymptomatic subjects, by culture and histological examination of biopsies in 324 consecutive endoscopy patients with chronic epigastric complaints, and by both the breath test and culture/histology in a subset of 92 patients. Sixty healthy Belgian students or hospital laboratory workers were also included for comparison. The prevalence of Helicobacter pylori was significantly higher in asymptomatic Zairian subjects (77.4%) than in the Belgians (30%; p less than 10(-6)). Infection was also acquired much earlier in life in Africans, 66% of the children aged 5 to 9 years already being infected versus none of the Belgian subjects below the age of 20 years. In Zaire, however, the prevalence of Helicobacter pylori in patients with gastroduodenal disorders (87.5%) was similar to that in the group of asymptomatic subjects (77.5%) after adjustment for age and other epidemiological parameters (gender, place of residency, education level, smoking and drinking habits) in a multivariate analysis. The high rate of acquisition of Helicobacter pylori infection in Zaire emphasizes the need to consider the baseline prevalence of Helicobacter pylori in a defined population when studying its association with various diseases.


Prevalence of antibodies to human immunodeficiency virus type 1 and condom use among outpatients at a sexually transmitted disease clinic in Rome.

To assess the prevalence of HIV-1 infection and study selected risk factors among patients attending a clinic for sexually transmitted diseases in Rome, 1442 outpatients seen consecutively between 20 February and 12 December 1989 were anonymously tested for anti-HIV-1. An evaluation of the trend of the HIV-1 infection was attempted by comparing the results of the present study with those obtained from a similar sample studied in 1986 in the same clinic. The overall estimated prevalence of anti-HIV-1 was 1.2% among heterosexual non-drug user subjects and 16.1% among homosexual or bisexual men. The anti-HIV-1 seropositivity was significantly higher in heterosexual subjects who reported sexual contact with intravenous drug users, as compared with those who did not report such exposure (12.5% vs 0.8%, p less than 0.005). Comparing the present data with those of a study conducted in 1986 in the same clinic, a lower prevalence of anti-HIV-1 was found among heterosexual subjects (1.2% in 1989 vs 6.0% in 1986, p less than 0.001). The availability after 1986 of several outpatient facilities attracting seropositive subjects and a change in the sexual behaviour of anti-HIV-1 positive subjects could explain this finding. Twenty percent of the heterosexual subjects and 62% of the homosexual or bisexual men reported consistent use of condoms.(ABSTRACT TRUNCATED AT 250 WORDS)


Influence of vaccination schedules and host factors on antibody response following hepatitis B vaccination.

In a prospective multicentre trial, the influence of schedule, compliance, age, sex and weight on the antibody response to hepatitis B vaccination was investigated. Comparison of the vaccination schedules 0, 1, 6 months (group 1; n = 143) and 0, 1, 2, 12 months (group 2; n = 141) was performed in months 3, 7 and 12. In addition, the antibody response was compared one month after the third and one and six months after the last vaccination. Seroprotection rates (anti-HBs greater than 10 IU/l) and antibody titres, given as geometric means (GMTs), were higher in group 1 at month 12 as well as one month after completion of three immunizations. More vaccinees of group 2, however, showed seroprotection at month 3 with higher GMTs. In addition, GMTs in group 2 were higher both one month and six months after the last vaccine dose. Determination of parallel corrected correlation factors demonstrated that age was the most important single factor, followed by body weight and sex. However, no more than 3% of the variation in the GMT can be explained by the influence of age. Due to decreased compliance with the four-dose schedule with a drop-out rate of approximately 10% of the vaccinees, the total percentage of initial vaccinees who in the end developed protective antibody levels was higher in the 0, 1, 6 months schedule. Thus, it can be concluded that subjects likely to comply will benefit from the 0, 1, 2, 12 months schedule as more rapid protection is obtained and the higher antibody levels after the booster vaccination at month 12 provide longer protection. However, vaccinees whose compliance might be questionable over a period of 12 months, should be selected for the vaccination 0, 1, 6 months schedule as compliance is at a higher level over this period and advantage can be taken of the booster effect of the third dose given in month 6.


Determination of neutralizing antibodies and specific immunoglobulin isotype levels in infants after vaccination against diphtheria.

Serum samples were obtained from 44 infants vaccinated against diphtheria at the ages of 3, 5 and 12 months with an aluminium-adsorbed diphtheria-tetanus toxoid vaccine containing 15 Lf units of diphtheria toxoid. Toxin-neutralizing antibodies (antitoxin) were measured by the Vero cell assay and IgG, IgM and IgA antibodies against diphtheria toxoid by enzyme-linked immunosorbent assay. A neutralizing antibody titer of 10 corresponded to 0.01 IU/ml, the level considered necessary for short-term protection. Geometric mean neutralizing antibody titers at 3, 5, 6, 12, 13 and 30 months were 28, 21, 173, 61, 1076 and 61. All children had titers of greater than or equal to 10 (greater than or equal to 0.01 IU/ml) between 6 and 30 months of age. At 30 months only 48% had titers of greater than or equal to 100 (greater than or equal to 0.01 IU/ml), the level considered necessary for long-term protection. Geometric mean IgG antibody levels were 13, 36, 216, 64, 649 and 57. IgG antibodies significantly correlated with neutralizing titers and predicted neutralizing antibodies above or below 10 and 100 with an accuracy of 96 and 82%, respectively. IgG antibodies could not, however, be used to predict individual neutralizing antibody titers with great accuracy. IgM antibodies were only detected after the third vaccination. IgA antibodies were not detected in any serum sample from ten infants tested. In conclusion, the Swedish vaccination schedule results in protective antibody levels in infants until at least 30 months of age. The decline of the antibody titers indicates a need for further studies to establish the duration of protection.


Isolation of Klebsiella terrigena from clinical specimens.

In a three-year survey conducted from 1988 to 1990 Klebsiella isolates from human clinical specimens were subjected to additional tests to identify any Klebsiella terrigena strains. Ten strains of Klebsiella terrigena (0.4%) were found among 2355 indole-negative Klebsiella isolates. Most of the isolates were recovered from the respiratory tract. In the API20EC system almost exclusively biotypes no. 1777771 and 1777671 were observed. Serotyping revealed capsule types K2, K5 and K18 in two strains each. In antibiotic susceptibility tests the strains were shown to be comparable in sensitivity to Klebsiella pneumoniae.


Spontaneous bacterial peritonitis caused by Listeria monocytogenes: two case reports and literature review.

Two new cases of spontaneous bacterial peritonitis (SBP) caused by Listeria monocytogenes are reported. Listeria monocytogenes was recovered from the ascitic fluid but not from the blood cultures of two adult diabetic inpatients with hepatic cirrhosis and SBP that had been treated empirically with cefotaxime. These two cases add to the 17 cases of Listeria monocytogenes SBP reported previously, stressing the relevance of this microorganism to this clinical condition. The recovery of Listeria monocytogenes from blood has been achieved in only half of the cases reported, suggesting the possibility of a direct translocation mechanism. Combinations of amino- or ureidopenicillins with beta-lactamase inhibitors or carbapenems might be more effective as empiric therapy of SBP in cirrhotic patients.


Changes in the susceptibility of Bacteroides fragilis group organisms to various antimicrobial agents 1979-1989.

The in vitro activity of metronidazole, chloramphenicol, clindamycin and 11 beta-lactam antibiotics against 135 clinical isolates of the Bacteroides fragilis group was compared. In addition, changes in the resistance patterns of members of the Bacteroides fragilis group isolated at the Hospital Universitario San Carlos in Madrid, Spain, between 1979 and 1989 were documented. The most active beta-lactam drugs were imipenem and beta-lactamase inhibitor combinations. In 1989, however, two strains were found to be resistant to imipenem and to all other beta-lactam agents tested. There was no emergence of resistance to metronidazole. Chloramphenicol was very effective: only one resistant strain was detected in 1979 and no chloramphenicol-resistant isolates were found during the rest of the study period. An outbreak of clindamycin resistance was noted in 1982, and the first cefoxitin resistant strains were recovered in 1985. The changing patterns of susceptibility of anaerobic bacteria to antimicrobial agents and the emergence of Bacteroides fragilis strains resistant to new beta-lactam agents suggest that periodic antimicrobial susceptibility tests should be performed in order to guide the selection of antimicrobial agents for therapy.


New high-content disks for determination of high-level aminoglycoside resistance in clinical isolates of Enterococcus faecalis.

Disks impregnated with 500 and 1000 micrograms of streptomycin, 1000 micrograms of kanamycin and 250 and 500 micrograms of gentamicin were used for detection of high-level resistance to aminoglycosides in 120 clinical isolates of Enterococcus faecalis. Fifty-seven strains were highly resistant to streptomycin, 80 to kanamycin and 41 to gentamicin. Using disks containing 500 micrograms of streptomycin, 1000 micrograms of kanamycin and 500 micrograms of gentamicin strains resistant to high levels of these drugs (97.9%, 100% and 100%, respectively) were accurately detected. Better discrimination between high-level and low-level resistance was achieved with a 500 micrograms streptomycin or gentamicin disk. Zone-size breakpoints are proposed for detection of high-level resistance by disk diffusion.


Evaluation of a commercial enzyme immunoassay kit for the detection of Clostridium difficile toxin A.

A new enzyme immunoassay (EIA) kit developed for the rapid detection of Clostridium difficile toxin A in faecal specimens, Premier (Meridian Diagnostics), was evaluated using 101 faecal specimens. Sixty-nine specimens were positive for Clostridium difficile by isolation of the organism and by cytotoxicity in tissue culture. The EIA for toxin A was positive in 49 of these 69 cases. No specimen that was negative for cytotoxicity was positive by EIA. Eight of the 32 specimens negative by both EIA and cytotoxicity assay yielded Clostridium difficile by culture. In five of these cases the cytotoxigenic status of the isolate was determined, and four were positive. There was no direct relationship between cytotoxin titre and EIA reading.


Activity of cefpirome combined with beta-lactamase inhibitors and affinity for the penicillin-binding proteins of methicillin-resistant Staphylococcus aureus.

The susceptibility of 47 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) to cefpirome, ceftazidime and methicillin was determined with Isosensitest media, with/without 5% NaCl and incubation at 30 degrees, 37 degrees and 44 degrees C for 24 and 48 h. At 24 h the MIC50 of cefpirome was 8 mg/l compared to 64 mg/l ceftazidime; at 48 h this increased to 32 mg/l cefpirome. The addition of 10 mg/l clavulanic acid or sulbactam lowered the MIC of cefpirome (at 48 h) by greater than four-fold in 23% and 11% of the strains, respectively. Cefpirome had primary affinity for penicillin-binding protein (PBP) 1 and 2 in five MRSA and one methicillin-susceptible Staphylococcus aureus. PBP 2a was present in all MRSA and was not saturated by 64 mg/l cefpirome. Clavulanic acid at a concentration of 10 mg/l bound to PBP 2 by greater than 50% in all strains, and when combined with cefpirome, the density of PBP 2a was also reduced but not completely abolished. The data from this study suggests that the mechanism of synergy of a beta-lactamase inhibitor plus a cephalosporin for MRSA may be due to an additive effect against PBPs and not just inhibition of a beta-lactamase. No cefpirome-resistant mutants could be selected from a methicillin-susceptible Staphylococcus aureus, but mutants were selected from an MRSA (expressing homogeneous methicillin resistance) for which MICs of cefpirome were 8 to 32 mg/l.


Effect of antimicrobial therapy on the specific serological response to Helicobacter pylori infection.

The systemic immune response to Helicobacter pylori was studied in 247 infected adult patients before antimicrobial therapy and at different intervals following therapy. Endoscopy with simultaneous collection of biopsies was performed in all patients immediately before treatment, 4 to 6 weeks after the end of therapy and 6 to 12 months later. A 14C-urea breath test was performed 3 to 6 months after the end of treatment. Biopsy specimens were cultured and examined histologically using Giemsa stain. Sera were tested for Helicobacter pylori IgG antibodies with a commercial enzyme immunoassay using species-specific antigens. Overall, Helicobacter pylori was eradicated in 120 patients while the other 127 remained infected with the organism. The follow-up period ranged from 4 weeks to 33 months (mean 10.2 months). Pretreatment IgG levels did not differ significantly between the two groups of patients. Six weeks after the end of treatment a slight but definite decrease in the IgG antibody levels was seen irrespective of treatment success. In the 127 patients who remained Helicobacter pylori-positive, the level of IgG antibodies remained stable or increased with time. A continuous fall in antibody levels was observed following bacterial eradication in the other 120 patients, but the difference in antibody levels between treatment responders and nonresponders became significant only more than six months after the end of treatment (p = 0.001). Serological testing may be useful for monitoring the outcome of long-term treatment of Helicobacter pylori infection and obviate the need for endoscopy.


Serodiagnosis of Helicobacter pylori infections by detection of immunoglobulin G antibodies using an immunoblot technique and enzyme immunoassay.

A transferable solid phase enzyme immunoassay (TSP-EIA) and an immunoblot technique were evaluated for the detection of IgG antibodies against Helicobacter pylori. Using the biopsy urease test as reference method, the sensitivity and specificity of the EIA were 96% and 100%, respectively. Immunoblot analysis was carried out by testing sera from patients with a positive urease test who suffered from type B gastritis, gastric and duodenal ulcers, and a negative control group. The immunoblotted Helicobacter pylori proteins showed reproducible immunoreactive bands at molecular weights of 130, 93, 75 and 67 kDa. The molecular weight protein fractions of Helicobacter pylori of 180 kDa and higher were found to be of minor immunological significance. Proteins of less than 60 kDa exhibited wide serum-specific variations in reactivity after immunostaining. No correlation between specific immunoblot patterns and clinical signs induced by Helicobacter pylori infection was observed.


Evaluation of a fluorescent DNA hybridization assay for the detection of Neisseria gonorrhoeae.

This study evaluates a four-hour fluorescent DNA hybridization assay using both known bacterial isolates and clinical specimens. A biotinylated oligonucleotide probe from a sequence of the plasmid-encoded gene cppB was used. Hybrids were detected by addition of a streptavidin-alkaline phosphatase conjugate, followed by incubation for 30 min in a fluorescent substrate for alkaline phosphatase. The level of detection of the fluorescent assay was 0.1 pg of cryptic plasmid DNA or 200 cfu of the plasmid-containing strain NG 34/85 of Neisseria gonorrhoeae. A total of 119 reference strains of Neisseria gonorrhoeae and other related bacteria were tested for reactivity with the probe. All Neisseria gonorrhoeae strains, including eight plasmid-free strains, hybridized with the probe. Fluorescence ratios were 2.67 for plasmid-free strains and 3.85 for plasmid-containing strains. Of the heterologous microorganisms tested, only one of six strains of Neisseria cinerea gave a fluorescence ratio above the 2.0 cut-off value for positivity with the probe at a cell density of 1 x 10(4) cfu. The probe was also evaluated using clinical specimens from 100 patients attending a clinic for sexually transmitted diseases. The sensitivity of the assay was 100% while the specificity was 97.5%. Positive and negative predictive values were 91.2% and 100%, respectively. The fluorescent DNA hybridization assay for the detection of Neisseria gonorrhoeae described here thus appears to be a highly specific and sensitive assay.


Serodiagnosis of Helicobacter pylori infections with an enzyme immunoassay using the chromatographically purified 120 kilodalton protein.

A membrane-associated 120 kDa protein of Helicobacter pylori with known species-specificity was isolated and used in an enzyme immunoassay (EIA) for the detection of Helicobacter pylori-specific IgG antibodies in patient sera. The EIA was compared with two other methods used for serodiagnosis of Helicobacter pylori infections: an EIA using sonicated whole Helicobacter pylori cell antigen and Western immunoblot. In a prospective study 127 unselected patients (76 patients with antrum gastritis, 51 patients without gastritis) who underwent gastroscopy were studied histologically and serologically. The EIA using the purified 120 kDa protein had the highest specificity (92%) compared with the EIA using a whole cell sonicate of a single Helicobacter pylori strain as antigen (60.7%) and the immunoblot (90.2%). The sensitivity was 96%, 100% and 92%, respectively. Sera of three control patients reacted strongly in all three methods, indicating possible Helicobacter pylori infection with negative histological findings. The EIA using the 120 kDa protein as antigen was shown to be a specific and sensitive technique for the serodiagnosis of Helicobacter pylori infections.


Evaluation of a new commercial system for the identification of Enterobacteriaceae and non-fermentative bacteria.

The performance of a new commercial semi-automatic system (Cobas Micro, Becton Dickinson) for identification of gram-negative fermentative and non-fermentative bacilli was evaluated using strains of clinical origin belonging to 48 different species. Two groups of strains were tested: 510 strains using a long incubation period (21 hours) and 158 strains using a short incubation period (5 hours). The correct identification rate without additional tests was 95.5% and 94.3% for the tests using a long and short incubation period respectively. The findings suggest that the system is highly accurate in the identification of most clinically important gram-negative rods, but shows some shortcomings in the identification of non-fermentative bacteria. The system is easy to use, and with some changes in the database and the inclusion of gram-positive and anaerobic bacteria would offer a valuable alternative to currently available automatic identification systems.


Outbreak of Chlamydia pneumoniae infection in four farm families.

The epidemiology of Chlamydia pneumoniae infection was studied in an outbreak in four farm families living close together in Denmark. Eleven of 20 members of the families studied had bronchitis or pneumonia characteristic of Chlamydia pneumoniae infection. Serologic evidence of Chlamydia pneumoniae as causative agent was strengthened by a high incidence of epidemic infection. Transmission within families and a high frequency of disease versus asymptomatic infection are two findings which deviate from epidemiological patterns of Chlamydia pneumoniae infection as currently known.


Detection of Chlamydia trachomatis by the polymerase chain reaction in young patients with acute epididymitis.

Specimens from 11 patients presenting with acute epididymitis were tested for the presence of Chlamydia trachomatis by an enzyme immunoassay (EIA), growth in McCoy cells and the polymerase chain reaction (PCR), and for other microorganisms by standard laboratory techniques. Chlamydia trachomatis urethral infection was detected in four patients by tissue culture, in three patients by EIA and in nine patients by PCR. These findings confirm the usually low detection rate of Chlamydia trachomatis by conventional tissue culture and EIA. Detection by PCR indicated both the diagnostic value of this technique and the importance of this organism in epididymitis.


Septicemia and hepatic abscess caused by Pediococcus acidilactici.

A case of postoperative Pediococcus acidilactici septicemia with parallel isolation of the organism from hepatic specimens is presented. Laboratory methods to identify this vancomycin-resistant gram-positive cocci are described. Very few cases of documented infections due to this bacterium have been reported in the literature.


A case of urinary tract infection caused by Corynebacterium urealyticum and coryneform group F1.

A case of urinary tract infection (UTI) caused by a fastidious, urea-splitting, antibiotic-sensitive coryneform, identified as CDC group F1, is described. The patient suffered from encrusted cystitis and had had previous and persistent UTIs caused by Corynebacterium urealyticum (formerly CDC group D2). Bacteriological cure was achieved after one month of treatment with amoxicillin plus acetohydroxamic acid.


Three cases of opportunistic infection caused by propionic acid producing Corynebacterium minutissimum.

Propionic acid producing strains of Corynebacterium minutissimum were isolated from three patients with opportunistic infections. One neutropenic patient was undergoing chemotherapy for prolymphocytic leukemia; the other two patients were undergoing hemodialysis and peritoneal dialysis respectively. An unusual feature of these three strains was their resistance to several antibiotics, which is seldom seen in diphtheroids other than Corynebacterium jeikeium and CDC group D2.


Occurrence and phenotypic properties of verotoxin producing Escherichia coli in sporadic cases of gastroenteritis.

Five verotoxin producing Escherichia coli strains were detected in 405 patients with infectious gastroenteritis and 3 such strains were detected in 11 patients with the hemolytic uremic syndrome in Switzerland. Production of verotoxin 2 was associated with the latter three strains. Four strains reacted with the probe for the virulence plasmid of Escherichia coli O157:H7, and six reacted with a recently described probe for the eae gene of enteropathogenic Escherichia coli. None of the strains was of serotype O157:H7. The methods available at present for detecting toxins or toxin genes will reliably detect all such verotoxin producing strains.


Evaluation of two commercial enzyme immunoassays for the diagnosis of Helicobacter pylori infection.

Sera from 65 patients with upper gastrointestinal tract symptoms and proven Helicobacter pylori infection, and from 42 negative controls were tested with two commercial EIAs (GAP test, BioRad; and ECP test, Biometra) and two non-commercial EIAs, one performed with whole sonicated cells and the other with acid extract of Helicobacter pylori as antigen. The GAP assay showed a sensitivity of 83.1% and a specificity of 47.6%. The ECP assay showed a sensitivity of 87.7% and a specificity of 61.9%. For both non-commercial EIAs these figures were 87.7% and 88.1%, respectively. Independent of the interpretive criteria established by the manufacturers, receiver operating characteristic curves were plotted for better evaluation of the four methods. Both commercial tests showed a lower probability of yielding a correct diagnosis than the non-commercial tests (p less than 0.05). Although commercial EIAs are convenient for the diagnosis of Helicobacter pylori infection, the accuracy of the two commercial tests evaluated in this study was lower compared to that of the two non-commercial EIAs.


Sensitivity of seven commercial assays in the detection of hepatitis B virus type 2-like infection.

Two hundred serum samples taken from patients with hepatitis B virus type 2-like infections were tested with seven commercial enzyme immunoassay methods for detection of HBsAg. Positive results were obtained with all methods in some samples, the rate of detection of HBsAg ranging from 9% to 90% for the different methods. A direct correlation was found between the analytical sensitivity of a method and its ability to yield positive results. It is suggested that these findings should be taken into consideration when selecting HBsAg detection methods in blood banks in order to avoid transmission of the HBV2 agent to recipients of blood or blood products.


Post-antibiotic effect of the new streptogramin RP 59500.

The post-antibiotic effect (PAE) of RP 59500, a new streptogramin antibiotic, was determined for Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Streptococcus pneumoniae, and Streptococcus pyogenes. A 30 min exposure of Staphylococcus aureus to 5 micrograms/ml of RP 59500 produced a PAE of 1.9-6.9 h, and a 60 min exposure of 2.5 micrograms/ml produced a PAE of 3.2-8 h. A 30 min exposure of 5 micrograms/ml of RP 59500 of coagulase-negative staphylococci produced a PAE of 2.5-7.5 h. PAEs of constitutively erythromycin-resistant staphylococcal isolates were shorter than were the PAEs of highly susceptible isolates. A 30 min exposure to 5 micrograms/ml of RP 59500 produced a PAE of 7.5-9.5 h for Streptococcus pneumoniae and a PAE of greater than 18 h for Streptococcus pyogenes. RP 59500 produced a longer PAE with Staphylococcus aureus than did vancomycin, oxacillin or erythromycin. These results suggest that RP 59500 may be administered less frequently than would be suggested by its half-life.


Comparative in vitro activity of cefdinir (CI-983; FK-482) against staphylococci, gram-negative bacilli and respiratory tract pathogens.

The in vitro activity of cefdinir (CI-983; FK-482), a new oral cephalosporin, was compared with that of other antimicrobial agents against clinical isolates of staphylococci, gram-negative bacilli and common respiratory tract pathogens. Cefdinir (MIC90 less than or equal to 2.0 micrograms/ml) was more active than cefixime (MIC90 greater than 64 micrograms/ml) and equally as active as cefuroxime (MIC90 2.0 micrograms/ml) against oxacillin-susceptible staphylococci. Cefdinir was active against Haemophilus influenzae, including beta-lactamase producers (MIC90 0.5 microgram/ml), Moraxella catarrhalis (MIC90 less than or equal to 0.12 microgram/ml), Streptococcus pneumoniae (MIC90 less than or equal to 0.06 microgram/ml) and Streptococcus pyogenes (MIC90 less than or equal to 0.06 microgram/ml). The activity of cefdinir against gram-negative bacilli was variable; organisms with chromosomal cephalosporinases were often resistant.


Comparative in vitro activity and beta-lactamase stability of RU29246, the active metabolite of HR916B.

HR 916B is a new orally absorbed cephalosporin. In tests its active metabolite, RU29246, inhibited Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus pneumoniae at less than or equal to 0.12 micrograms/ml, which is similar to the antibacterial activity of cefuroxime, and was more active than cefaclor. It was also more active (MIC 2 micrograms/ml) than cefixime, cefuroxime, cefaclor and cefotaxime against staphylococci. RU29246 inhibited Escherichia coli, Klebsiella pneumoniae, Citrobacter diversus, Klebsiella oxytoca, Proteus mirabilis, Providencia stuartii and Salmonella spp. at less than or equal to 1 microgram/ml, thus being more active than cefuroxime and cefaclor, but was less active than cefixime and cefotaxime. It did not inhibit Pseudomonas aeruginosa and other Pseudomonas spp., Enterobacter spp., Serratia marcescens or Bacteroides fragilis. RU29246 was not hydrolyzed by TEM-1, Staphylococcus aureus TEM-2 or Moraxella catarrhalis beta-lactamases, but was hydrolyzed by TEM-3 and the chromosomal beta-lactamases of Proteus vulgaris and Morganella morganii. Plasmid and chromosomal beta-lactamases were inhibited by RU29246.


An anatomical filter for exposure equalization in mammography.

An anatomical filter has been designed, tested and subsequently used in clinical practice to equalize optical density over the entire mammographic image, thus eliminating the need for dual exposure whenever both the mammary gland and the peripheral structures of the breast must be clearly visualized. The use of the filter results in a reduction of the optical density, at the peripheral structures of the breast, with a simultaneous increase of the contrast, without causing deterioration of the mammary gland image. Improved visualization of the connective tissue, the skin, the nipple and the subcutaneous adipose tissue is achieved, as well as minimization of the radiation dose to the breast for patients with an indication of peripheral breast lesions.


Radial scars detected mammographically in a breast cancer screening programme.

Radial scars are getting more and more common since the implementation of mammography as a diagnostic tool in screening women for breast cancer. At the Karolinska Hospital, 18,987 asymptomatic women, between the ages of 50 and 69, were screened for breast cancer by means of mammography during the period August 1989 to May 1991. A total of 735 (3.87%) women were recalled for additional views after initial mammograms and 463 (2.44%) were assessed with the help of cytology. In all 175 (0.92%) women were selected for surgery and 146 (0.77%) had histologically verified cancers. The remaining 29 (0.15%) had non-malignant lesions of which 11 (0.06%) were radial scars. All radial scars were diagnosed on mammograms and later confirmed with histology. The radiologic characteristics were found to be (a) rather thick and long radiating structures accompanied by radiolucent linear structures parallel to some of the spicules, (b) absence of calcifications, (c) radiolucent areas in the central body of the lesion, (d) an average mean size of 6 mm and (e) changing image in different views. Most of the lesions, 73% (8/11), were in moderately dense breasts and there was no specific relation to the right or left breast. A majority of radial scars, 64% (7/11), were found in the upper outer quadrants, 27% (3/11) in the lower outer quadrants and 9% (1/11) in the lower inner quadrant. Literature shows that histology uses many synonyms for radial scars and therefore team work between the radiologists and pathologists is suggested for better conformity of the diagnosis.


Follow-up study of renal transplants by duplex Doppler and gray-scale ultrasound.

In the early postoperative period after renal transplantation 388 follow-up ultrasound examinations were performed in 77 patients. Over a period of 18 months standardized duplex indices (resistive index, pulsatility index) and gray-scale parameters (parenchyma/sinus index; medulla/cortex index) were sampled. These data were correlated retrospectively with clinical and pathological diagnoses. To delineate the individual course of duplex and gray-scale indices during different transplant diseases we created a new parameter: the MID (maximal index difference) which is a result of the difference between the highest index during the phase of renal dysfunction and the lowest index during the phase of normal renal function. This MID, calculated for duplex indices and for the parenchyma/sinus index, indicated significant differences in the behavior of renal transplants during the four main diseases: interstitial rejection, vascular rejection, acute tubular necrosis and Cyclosporine A nephrotoxicity. Using the MIDs, a table of cut-off values was established, which enables to differentiate retrospectively these four transplant complications with a sensitivity of 84% and specificity of 81%. In our opinion consequent follow-up examinations with duplex and gray-scale sonography should be performed, enabling sonography to become a helpful diagnostic instrument in the monitoring of renal transplants.


Talocalcaneal coalition: computed tomography and magnetic resonance imaging diagnosis.

A correct evaluation of site and extension of the talocalcaneal coalition inducing biomechanical ankle alterations is very important for planning therapy. Four male patients were submitted to computed tomography (CT) and three of them were also examined by means of magnetic resonance imaging (MRI). In one patient, studied by CT only, a bilateral talocalcaneal coalition was present, while the other three patients, controlled with CT and MRI, were affected by monolateral talocalcaneal coalition which was of osseous type in one case and fibrocartilaginous in two cases. CT and MRI provided detailed information on type and extension of the coalition and both helped in distinguishing between osseous and fibrocartilaginous forms. Only MRI showed an area of subchondral ischemic disease of the posterior subtalar joint in one patient with monolateral fibrocartilaginous talocalcaneal coalition. Compared with CT, MRI proved to be more accurate in evaluation of the talocalcaneal coalition, due to its wider display capability.


Color Doppler imaging of the right gastroepiploic artery as an in situ coronary artery bypass graft.

In recent years the right gastroepiploic artery (GEA) has been used as an in situ graft in coronary artery bypass grafting (CABG). The specific anatomical course of the GEA graft enables the use of color Doppler imaging technique to evaluate its patency. The results in 21 patients demonstrate the efficiency of this technique; postoperative angiography to establish patency can therefore be avoided.


Flushable stent-system for internal drainage in occlusive jaundice.

The effectiveness of biliary stents may be reduced as a result of obstruction by tumor material, bile salts or detritus. To circumvent this problem we developed a prosthesis system, which allows flushing and repetitive radiological control via a subcutaneous port. Prostheses were implanted in 26 patients presenting with inoperable occlusive lesions of the bile duct. Patency was regularly monitored by checking the bilirubin and alkaline phosphatase levels and using port-cholangiography. Catheter function was easily maintained in 92% of the patients and ended upon malignancy related death. In case of dysfunction, drainage could generally be restored with intensive flushing. This new flushable stent-system was easily implantable, could be exchanged without renewed percutaneous transhepatic puncture and allowed flushing, external drainage, bile probes for bacteriological examinations and follow up cholangiography via the subcutaneous placed port.


Duplex ultrasound diagnosis of symptomatic proximal deep vein thrombosis of lower limbs.

Real time ultrasound (US) was used to examine 165 consecutive inpatients with clinically suspected deep vein thrombosis of lower limbs. In order to evaluate accuracy, the results of non-invasive techniques were compared with ascending venography, performed in all patients. Assessment included only femoro-popliteal veins, because of difficulty in visualizing calf vein with US. Diagnosis of thrombosis was based on noncompressibility of the examined veins; pulsed Doppler provided further information by evaluating blood flow. In our series Duplex ultrasound was very accurate in detecting acute thrombosis of the proximal veins, sensitivity being 97% and specificity 98%. With US it is also possible to detect conditions that mimic deep vein thrombosis, such as muscular rupture, hematoma, popliteal cyst or compressive tumors. In conclusion US is considered a valid alternative to contrast venography in the diagnosis of proximal vein thrombosis of lower limbs.


Computed tomographic staging of esophageal carcinoma: a study on interobserver variation and correlation with pathological findings.

Despite numerous reports on the efficacy of CT in the staging of esophageal carcinoma, no data are available on the reproducibility of the procedure. Three experienced radiologists independently reviewed the CT scans of 35 patients retrospectively. Calculation of interobserver variation was performed using the kappa statistic. The CT findings of each observer were subsequently correlated with the surgical and pathological findings of 17 patients. There was a large interobserver variation concerning involvement of the aorta, pulmonary vessels, vertebral column, stomach and lymph nodes, ranging from poor to excellent agreement. Agreement between observers on extension of the disease to the tracheobronchial tree, pericardium and liver was good or excellent. Agreement between the CT findings of all observers and the surgical findings for invasive growth was poor. CT pathological correlation of the three observers showed sensitivities ranging from 50 to 57%, specificities ranging from 50 to 60% and accuracies ranging from 46 to 71%. It can be concluded from this study that patients with positive CT findings for involvement of the tracheobronchial tree, the pericardium and the liver should be considered unresectable for cure. Negative findings, however, should be interpreted with caution, because involvement of other structures may still be present. Despite optimistic reports on the efficacy of CT in the pretherapy staging of esophageal neoplasms, this modality has its limitations.


Transbrachial approach for aortic and selective supraaortic vessel catheterization using a safe and easy technique to reform the Simmons II catheter tip.

A total of 286 patients (158 outpatients) were examined by intra-arterial DSA in the evaluation of cerebrovascular disease using a transbrachial approach. In all cases a 5F introducer sheath, a 5F pigtail catheter for aortic arch injection and a 5F Simmons II catheter for selective catheterization were used. Excellent demonstration of aortic arch and supraaortic arteries (including intracranial circulation) was obtained (92.2-100%). The complication rate was favorable, with only one major complication (thrombosis of an axillary artery). The use of an introducer sheath minimizes local complications and vessel wall damage during catheter exchange. Aortic arch injection must always be performed prior to selective catheterization. The results of selective catheterization prove the suitability of the Simmons II catheter, whose typical shape was easily and safely obtained using the configuration of the pigtail catheter and a 180 cm long guide wire for catheter exchange. Using the technique as described, the transbrachial approach is a safe and easy way for optimal vascular evaluation in cerebrovascular disease, especially useful in outpatients.


Tension mediastinal emphysema: emergency percutaneous drainage with CT guidance.

Four patients aged 8 to 54 years, under mechanical ventilation, presented with sudden tension mediastinal emphysema and exhibited typical clinical symptoms of compromised venous return. Diagnosis of tension mediastinal emphysema was confirmed by CT. A percutaneous catheter with a diameter varying from F12 to F20 was inserted in the anterior mediastinal compartment with CT control and connected to a waterseal aspiration. Emergency treatment was efficient in all patients. Percutaneous aspiration was continued for 3 to 20 days.


Family history as an independent risk factor of coronary artery disease.

The relationship between family history of ischaemic heart disease and the presence of coronary heart disease was studied in 387 patients undergoing routine coronary arteriography prior to valve replacement. One hundred and seven patients (27.6%) had a family history of ischaemic heart disease. Of these, 52 (48.6%) had significant coronary artery disease compared with 60 of 280 (21.4%) patients without a family history (P < 0.001). The overall severity (coronary score) and extent (number of vessels) of coronary artery disease was greater in those patients with a family history (P < 0.001). Moreover, the incidence of significant coronary disease increases as the number of relatives with ischaemic heart disease also increase (P < 0.001). Multiple logistic regression analysis suggests that family history is an independent predictor of the presence of significant coronary artery disease.


Comparative trial of Omnipaque 350 (iohexol) and Telebrix 350 (sodium-meglumine-ioxithalamate) in left ventriculography and coronary arteriography.

In a double-blind randomized trial, the hemodynamic and electrophysiologic effects of the low-osmolar nonionic contrast medium iohexol (Omnipaque) and the standard high-osmolar ionic monomer sodium-meglumine-ioxithalamate (Telebrix) at left ventricular angiography and selective coronary arteriography were evaluated. Sixty patients were divided into two groups of 30 patients; one group received Omnipaque in a dosage of 350 mgI/ml and the other group received Telebrix in a dosage of 350 mgI/ml. The Omnipaque showed significantly less effects on heart rate and myocardial contractility, and induced less electrophysiological changes than did Telebrix. However, there was a significant increase of 10% in the diameter of the left coronary artery following selective coronary injection with Telebrix, while Omnipaque induced practically no change in vessel diameter. All hemodynamic and electrophysiologic effects proved to be short-lasting. We conclude that ionic and nonionic agents are similarly efficacious in providing adequate images with minimal risk to the patient. However, the nonionic agents exert slightly more alterations in cardiac hemodynamics and in electrocardiographic intervals. The vasodilatory effect on coronary artery diameter by Telebrix may entail a more rapid clearance of contrast medium from the coronary circulation, which might be of some advantage over nonionic contrast media.


High-resolution MR imaging of the inner ear: findings in Menière's disease.

Symptoms in Menière's disease are characterized by hydrops of the endolymphatic system with recurrent rupture of the membranous labyrinth. The primary cause of the increased endolymphatic volume appears to be an imbalance between secretion and resorption of the endolymph which may be due to an obstruction of the membranous endolymphatic duct and sac, located in the vestibular aqueduct. The membranous endolymphatic duct and sac are not expected to be visualized using conventional tomography and high-resolution computed tomography (HR-CT), whereas, these are identified with high resolution MRI (HR-MRI). By HR-MRI, we proposed to demonstrate morphological alternation in 12 patients with Menière's disease, this group was compared with a group of 20 healthy subjects. The degree of visualization on HR-MRI of the membranous endolymphatic duct and sac running through the vestibular aqueduct in the bony canal was assessed. There was a distinct decrease in visualization of the membranous endolymphatic duct and sac in the Menière's group. The results confirm the value of the HR-MRI technique to identify an anatomical abnormality, which is directly correlated with the lesion in cases of unilateral Menière's disease.


Exercise-induced QRS changes in healthy men and women: a multivariate analysis on their relation to background data and exercise performance.

Changes in the QRS segment during exercise have repeatedly been suggested to provide diagnostic information with respect to ischaemic heart disease, but the subject is controversial. In order to study the possibly confounding effects of gender, age, resting ECG and exercise performance, 50 healthy subjects were investigated with computerized vectorcardiography during a maximal ergometer exercise test. The overall change in the QRS complex decreased significantly with age and female gender (P < 0.001). However, these responses were better explained by baseline QRS size, change in heart rate and systolic blood pressure (adjusted r2 > 0.70, vs adjusted r2 > 0.41). Effects of age were seen in the Y-lead, and gender effects in the X- and Z-leads (P < 0.0001). In multivariate analyses, X- and Y-lead alterations correlated negatively to change in heart rate and resting QRS size (X-lead; adjusted r2 > 0.50, Y-lead; r2 > 0.44). Z-lead alterations correlated negatively with female gender and resting Z-lead QRS size (adjusted r2 > 0.31). ST changes correlated with QRS changes in the X- and Y-leads (P < 0.05). QRS changes immediately after exercise correlated with alterations during exercise (P < 0.004), maximal load (P < 0.01) and time to hypotension post-exercise (X- and Z-lead; P < 0.02). In conclusion, QRS changes appear to be related to baseline QRS size, change in heart rate and ST change, factors which may have important confounding effects. Consideration of these factors may help in resolving the controversy surrounding QRS changes.


Paradoxical early lengthening and subsequent linear shortening of the QT interval in response to exercise.

The QT responses to exercise during ventricular pacing were evaluated in 12 patients in whom permanent pacemakers were implanted for complete heart block. The initial response of the QT to exercise was a paradoxical lengthening during the first minute of exercise (mean 4.8 ms P < 0.01). Thereafter, the QT was found to shorten in a linear fashion in response to increasing exercise, both in terms of exercise duration (r = 0.787; P < 0.001) and atrial rate (r = 0.712; P < 0.001). The total QT shortening with exercise was small (20 ms for a mean increase in atrial rate of 60 beats.min-1) and displayed substantial inter-individual variability (9-31 ms). These results explain some of the limitations of the QT pacemaker, and provide insights in to the dynamics of the QT response, which may help tailor the programming of these systems to the individual patient.


Catheter ablation of free wall accessory atrioventricular pathways in 89 patients with Wolff-Parkinson-White syndrome--comparison of direct current and radiofrequency ablation.

To evaluate and compare the safety and efficacy of catheter-mediated direct current (DC) or radiofrequency (RF) ablation in patients with free wall accessory atrioventricular pathways, 89 patients with free wall accessory atrioventricular pathway (AP)-mediated tachyarrhythmias underwent catheter ablation. Electrophysiological parameters were similar in the patients with DC (group I, 29 patients with 30 APs) or RF (group II, 60 patients with 64 APs) ablation. Immediately after ablation, it was seen that 27 of 30 APs (90%) had been ablated successfully with DC, but two of the 27 APs had early return of conduction and received a second ablation session; three of eight APs (38%) and 53 of 56 APs (95%) were ablated successfully with RF through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Seven of the eight APs who had a failed RF ablation later had a successful DC ablation. During the follow-up (group I, 14 to 27; group II, 8 to 14 months), all successfully ablated patients had no recurrence of tachycardia. Complications in DC ablation included transient hypotension (two patients), and pulmonary air-trapping (two patients); in RF ablation the complications included cardiac tamponade (1 patient) and suspicious aortic dissection (1 patient); myocardial injury (reflected by peak CK-MB, 34 +/- 5 vs 15 +/- 4 IU.l-1) and pro-arrhythmic effects (new atrial and ventricular arrhythmias) were more severe in those who had DC ablation. Procedure and radiation exposure time were significantly longer in RF ablation (DC, 3.6 +/- 0.2 h, 34 +/- 4 min; RF 4.0 +/- 0.4 h, 46 +/- 10 min). This study confirms that RF ablation with a large-tip electrode catheter is an effective and relatively safe non-surgical method for treatment of free wall accessory atrioventricular pathway-mediated tachyarrhythmias.


Neuroradiologic abnormalities in Marchiafava-Bignami disease of benign evolution.

Marchiafava-Bignami disease has been recognized since 1903, but only recently has it become possible to achieve a probable diagnosis before death occurs. Imaging of the central nervous system with MR and CT have contributed significantly to such a diagnosis. Two cases of the disease are reported in patients, aged 33 and 59 years, with benign evolution of neurologic symptoms the diagnosis was confirmed by neurologic imaging with MR and CT and both were studied with evoked responses. Reversibility of the disease and possible prognostic indicators in these and other patients reported in the literature are discussed. The important role that diagnostic procedures, especially MR imaging, play in the management of this disease is emphasized.


Computed tomography and magnetic resonance imaging in the preoperative work-up for cochlear implantation.

The role of CT and MRI in the evaluation of patients for possible insertion of a multichannel intracochlear hearing device was appraised. The study included 52 patients who underwent both CT and MRI examinations, 40 of whom were later operated on. Coronal and axial T2-weighted spin-echo sequences were performed in 25 volunteers with normal hearing and in 47 adult patients. In 5 patients, instead of a T2-weighted spin-echo sequence, a T2*-weighted gradient echo 3D sequence with axial presaturation was used. In 39 patients with normal appearances on CT and MRI, the implant device was successfully inserted. One patient who underwent surgery had a reduced cochlear signal on MRI but a normal CT scan; however, at surgery, the implant device could only be inserted into the first turn of the cochlea, due to fibrous obliteration. In 3 of 12 patients who were not operated upon, the results of diagnostic imaging indicated that the insertion of an intracochlear hearing device was not useful. Our experience indicates that, with reduced cochlear fluid signal intensities on MRI, fibrous obliteration of the cochlear turns is likely to be present. MRI proved to be a useful adjunct to CT, but the latter was necessary for the evaluation of bony abnormalities. Gradient echo sequences can successfully replace time-consuming T2-weighted spin-echo sequences.


Too early for cardiac transplantation--the right decision?

In 109 out of 479 patients who were referred for cardiac transplantation it was considered to be too early to put them on the waiting list for a donor heart. The clinical course of these 109 patients was analysed in order to verify whether this decision had been right. The mean age of the patients was 43 years, half of them suffered from ischaemic heart disease. The systolic left ventricular function of the patients was severely depressed (mean left ventricular ejection fraction 21%) and the left ventricular cavity was markedly dilated (mean echocardiographic end diastolic dimension 73 mm). Functional capacity, measured by bicycle ergometry, was low: mean maximal workload 62% of the expected load for gender, height and age. The median follow-up duration was 31 months. The survival rate of the patients was better than that of 175 patients who were accepted for transplantation after referral, 92%, 87%, 81%, 71% and 73%, 73%, 71%, 68% after 1, 2, 3 and 4 years respectively. Re-assessment was necessary in 29% of the patients within 1 year and in 52% within 3 years. Twenty patients died: 12 patients died before re-assessment had been initiated (eight sudden deaths), six patients because of progressive heart failure before heart transplantation could be performed and two patients died after heart transplantation. Left ventricular ejection fraction, pulmonary capillary wedge pressure and transpulmonary gradient were not reliable predictors of the course of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)


Usefulness of dipyridamole-echocardiographic test to identify jeopardized myocardium after thrombolysis. Limited clinical predictivity of dipyridamole-echocardiographic test in convalescing acute myocardial infarction: correlation with coronary angiography.

A dipyridamole-echocardiographic test (DET) was carried out to find out how safe and useful it was in predicting clinical outcome and in identifying patients at risk. The test was performed in 107 asymptomatic patients early (5 to 8 days) after a first acute uncomplicated myocardial infarction managed with thrombolytic therapy. All patients were followed up for a mean of 15 months and 94 underwent coronary angiography. The test was considered positive if transient asynergy of contraction was newly detected either in the infarct and adjacent areas or in the remote zones; two subsets were studied, according to the dose of dipyridamole (0.56 or 0.84 mg.kg-1) needed to induce ischaemia. The test was accomplished satisfactorily in 96% of patients. Intra-inter-observer agreements were 88% and 91% respectively. The test also proved safe at the high infusion dose. During the follow-up period, two patients died, one experienced re-infarction and 12 (12%) developed recurrence of angina. DET was abnormal in 32 patients (adjacent and remote asynergy in 28 and four patients respectively): 18 had a critical and two a non-critical stenosis in the infarct-related vessel, and nine had an occluded artery with collateral distal flow. Multivessel disease was present in 11 patients considered positive, four in the remote and seven in the adjacent zones. However, 20 patients with negative DET results had multivessel disease. Of the positive DET patients, seven had angina. There were eight total events in the 71 negative DET patients, five of whom had multivessel disease. Abnormality was more pronounced in positive DET patients, but did not influence the outcome.(ABSTRACT TRUNCATED AT 250 WORDS)


Pharmacological stress echocardiography in the diagnosis of coronary artery disease and myocardial ischaemia: a comparison between dobutamine and dipyridamole.

The objective of this study was to relate regional wall motion abnormalities assessed by dobutamine and dipyridamole stress echocardiography to quantitative measurements of coronary artery stenoses in consecutive patients referred for coronary angiography, and to compare haemodynamic effects of and complications related to the two agents. Patients underwent stress echoes on separate days in random sequence and had coronary angiography within 3 days of stress echocardiography. Echocardiograms were assessed by two investigators unaware of the patients' coronary anatomy. Coronary angiograms were also assessed quantitatively using the computer-assisted Cardiovascular Angiography Analysis System. There were 46 consecutive patients referred for coronary angiography; 28 were using beta-antagonists. Main outcome measures were sensitivity and specificity for dobutamine and dipyridamole stress echocardiography for detection of coronary artery disease (wall motion abnormalities at rest or stress) and myocardial ischaemia (stress induced new wall motion abnormalities). Sensitivity for the detection of myocardial ischaemia was found to be 57% for dobutamine and 64% for dipyridamole. Specificities were 78% and 89% respectively. Sensitivities for detection of coronary artery disease (lesion > or = 50% diameter stenosis) was 79% for dobutamine and 82% for dipyridamole; specificities were 78% and 89% respectively. These differences between the two agents are not significant. There were no severe side effects with either agent. Mean heart rate rose significantly with both tests but was higher with dobutamine; mean systolic blood pressure rose with dobutamine and fell with dipyridamole. It was concluded that dobutamine and dipyridamole stress echocardiography have similar sensitivities and specificities for detection of myocardial ischaemia and coronary artery disease although the haemodynamic effects of the two agents are different. Both are free from serious complications.


The use of an exponential protocol for bicycle and treadmill exercise testing in patients with chronic cardiac failure.

We have studied a standardized exercise protocol suitable for use with a treadmill or bicycle (STEEP protocol) and compared it with a modified Bruce treadmill protocol in a group of patients with chronic cardiac failure. The STEEP protocol has been previously validated in normal subjects. Exercise time (6.79 +/- 2.42 vs 5.34 +/- 1.95 min, P < 0.05) and peak VO2 (16.66 +/- 4.09 vs 15.01 +/- 3.72 ml.min-1.kg-1, P < 0.05) were greater with the STEEP treadmill compared with the bicycle protocol, but VO2 was very similar at equal exercise stages in both modalities. Heart rate and respiratory exchange ratio tended to be greater during bicycle exercise at equal stages. Exercise time was greater with the modified Bruce protocol (9.00 +/- 3.02 min, P < 0.05) than with either STEEP protocol, but peak VO2 (17.13 +/- 4.52 ml.min-1.kg-1) was similar to that obtained with the STEEP treadmill test. We conclude that the STEEP protocol may be used to test patients with chronic cardiac failure, and that exercise times relate well in both treadmill and bicycle. The protocol should prove useful in studies involving a wide range of exercise capacities or both bicycle and treadmill exercise.


Cardiac involvement in thalassaemia major: altered atrial natriuretic peptide levels in asymptomatic patients.

Congestive heart failure is the most common cause of death in young adults with thalassaemia major. In the present study we compared atrial natriuretic peptide levels (ANP) in 30 asymptomatic patients with thalassaemia major (aged 16.6 +/- 6.4 years), normal left ventricular diastolic cavity dimension and systolic function, with 30 aged and sex matched normal control subjects. ANP levels were significantly higher in patients with thalassaemia major compared to controls (93.9 +/- 26.3 pg.ml-1 vs 51.8 +/- 26.5 pg.ml-1; P < 0.001). Plasmatic renin activity, aldosterone, urinary sodium and catecholamine levels at basal conditions did not differ significantly in these two groups (ns). Blood volume stimulation (blood transfusion) in thalassaemic patients was followed by an increase of mean ANP values (93.9 +/- 26.3 to 109.1 +/- 40.5 pg.ml-1; P < 0.03). ANP basal levels above two standard deviations of the mean values obtained in normal control subjects were considered as abnormal and found to be in close correlation with the presence of diastolic dysfunction of the left ventricle identified by Doppler echocardiography. The method has a 57% sensitivity and a 91% specificity for revealing pre-clinical cardiac involvement (P < 0.02). Although a longer observation period is necessary in order to define the clinical and prognostic significance of these data, our results show that an increase in ANP basal values is present in asymptomatic patients with thalassaemia major. This suggests initial myocardial involvement, while ANP response to volume overload is maintained.


Automated versus observer blood pressure as determinants of left ventricular structure.

We studied the contribution of automated blood pressure measurements to the variation in left ventricular structural characteristics, independent of pressure measured by an observer. Thirty eight patients referred for hypertension underwent 24 h blood pressure monitoring. Echocardiography and repeated blood pressure measurements were taken on 2 different days by an observer and by the use of the Dinamap 845 device. Blood pressure by the observer averaged 157/101 mmHg, Dinamap pressure 152/94 mmHg, 24 h pressure 137/92 mmHg, left ventricular mass 218 g and mean wall thickness 12.7 mm. Left ventricular mass and wall thickness were related (P < 0.05) to systolic observer (r = +0.46; r = +0.47), Dinamap (r = +0.42; r = +0.41) and 24 h blood pressure (r = +0.46; r = +0.53); the correlation coefficients were lower (r = +0.35 to +0.51; P < 0.05) for diastolic pressure. These relations were independent of age, gender, height, weight and heart rate. The Dinamap pressure did not contribute to the difference in the left ventricular structural characteristics, independent of the observer pressure. The 24 h ambulatory pressure explained a small but significant (P < 0.05) fraction of the variation in mean wall thickness in addition to the observer pressure. Left ventricular mass and mean wall thickness were not related to the day-night difference in blood pressure (P > 0.25). In conclusion, observer, Dinamap and ambulatory pressures are significantly related to cardiac structural variables. Ambulatory pressure, but not Dinamap pressure, explains a small part of wall thickness variance in addition to well-standardized pressure measured by an observer.


Effects of impaired lung function and pulmonary regurgitation on maximal exercise capacity in patients with repaired tetralogy of Fallot.

Long-term haemodynamic results and exercise capacity were studied in 34 patients with tetralogy of Fallot (24 men and 10 women) repaired 10.0 +/- 4.9 (mean +/- SD) years previously and compared to 34 healthy matched controls. All subjects were studied by resting spirometry, echocardiography and a symptom limited treadmill exercise test (modified Bruce protocol). The maximal oxygen consumption was 38.2 +/- 8.0 ml.kg-1.min-1 in patients and 48.1 +/- 8.1 ml.kg-1.min-1 in the control group (P < 0.001). Reduced maximal oxygen consumption was found in patients with low vital capacity (VC) and pulmonary regurgitation (PR). The ventilatory anaerobic threshold (VAT) was 23.8 +/- 0.6 ml.kg-1.min-1 and 29.9 +/- 0.6 ml.kg-1.min-1 in patients and controls, respectively (P < 0.001). VC was 3.4 +/- 1.21 in patients and 4.0 +/- 1.31 in controls (P < 0.02). In the patients, maximal ventilation was reduced and at submaximal exercise, the breathing frequency increased. Heart rates during exercise were similar in patients and controls. Tricuspid regurgitation (TR) was detected in 20 patients (58.8%); however, the exercise capacity was not reduced. Thus, impaired exercise capacity in tetralogy of Fallot is partly due to reduced resting lung function, pulmonary regurgitation and low ventilatory anaerobic threshold.