Ploidy analysis of field cancerization and cancer development in the hamster cheek pouch carcinogenesis model

BACKGROUND

The hamster cheek-pouch carcinogenesis model is a well-known animal system that closely mimics the development of premalignant and malignant lesions in human oral cancer. Our aim was to numerically characterize the premalignant and malignant lesions and expressions of field cancerization in this model using ploidy as the end-point.

METHODS

To study the DNA content and proliferation status of the cells in this model we assessed the Feulgen reaction and the immunohistochemical reaction for 5-bromo-2-deoxiuridine (BrdU) in different histological areas of serial tissue sections of the cheek pouches of animals injected with BrdU.

RESULTS

Ploidy values were higher in cancerized epithelia with no unusual microscopic features (NUMF), in preneoplastic and tumor areas than in control epithelia. The aneuploidy index was higher in NUMF areas than in control and differed significantly from control in preneoplastic areas and carcinoma.

CONCLUSIONS

The unexpected alteration in DNA content observed in NUMF epithelia is of great relevance as a biomarker of field cancerized areas.

In vitro sensitivity of human gastric cancer cells (HGC-27) to Helicobacter pylori cytotoxin

BACKGROUND

The VacA cytotoxin produced by Helicobacter pylori is considered an important co-factor in the pathogenesis of chronic gastritis, peptic ulcer and gastric carcinoma. The toxin remains partly bound on the bacterial surface, but a certain amount is secreted and can bind receptors on gastric epithelium. The vacuolizing activity of this toxin is related to alteration of endo-lysosomic function and pore formation into plasmatic membrane.

METHODS

We investigated the 'in vitro' effect of filtrates obtained from two broth cultures of H. pylori with different genotype (vacA+ and vacA-) as verified by PCR. The effect was studied on three cell lines of epithelial origin: HeLa cells (reference strain for testing vacuolization), human transformed keratinocytes HaCaT, human gastric carcinoma cells HGC-27, and on a murine leukaemia WEHI-3B. The filtrate concentrations capable of giving vacuolization (NRU test), antiproliferative and cytotoxic effects (MTT test) were determined. The modulating effect of filtrates on drug toxicity was investigated on HeLa and HGC-27 cells by testing topoisomerase inhibitors (Ciprofloxacin and Camptothecin) and non-steroidal anti-inflammatory molecules (Aspirin and Indomethacin).

RESULTS

Our results confirm that vacuolizing activity is present only in VacA+ filtrate and that HaCaT and HeLa cells show a similar sensitivity, whereas gastric HGC-27 cells appear significantly resistant to VacA+ activity. Although VacA filtrate does not produce vacuolisation, it affects the cell proliferation and is cytotoxic to the four cell lines. Both the VacA+ and VacA- filtrates (at non-cytotoxic concentrations) produce a decrease in drug toxicity with the unique exception of Ciprofloxacin to gastric HGC-27 cells, which in the presence of VacA+ and VacA- produces a significant increase in toxicity.

CONCLUSIONS

These data suggest that products from H. pylori (other than those that have antiproliferative and toxic activity) may modulate the sensitivity of cells to drugs 'in vitro'. If this also occurs 'in vivo', we can assume that H. pylori products interfere with drug activity on gastric tissue and also with other factors (such as cytokines) with a role in the genesis of diseases in which Helicobacters are potentially involved.

Selection criteria and long-term results of surgery in symptomatic rectocele

BACKGROUND

The aim of this study was to confirm some selection criteria for the transrectal repair of the anterior rectocele and to compare our surgical results with those reported in the literature.

METHODS

From January 1992 to December 1999, 30 females (mean age 52.9 years, range 28-70 yrs) affected by anterior rectocele were prospectively evaluated with a standard questionnaire, clinical examination, proctosigmoidoscopy, colonic transit time, dynamic defecography, anal EMG, anal manometry. Then, they were submitted to transrectal repair of rectocele with anterior plication of the rectal muscular wall. Fourteen (46.6%) of them were also submitted to perineal levatorplasty. Patients were followed postoperatively (mean 25.7 months) with the same standard questionnaire, clinical examination, defecography, and manometry. Results were tested by Fisher's Exact text, Wilcoxon's test, and "t"-test.

RESULTS

Rectal dyschezia, incomplete evacuation, digital help in defecating, mean stool frequency, and rectal bleeding significantly improved. After 3 months, 30% of patients had no complaints, 40% had only 1-2 episodes/month complaints, 13.3% had evacuation only using laxatives, and 16.6% were unchanged. Defecography showed a significant reduction of the rectocele in 70% of patients after 3 months. Manometric parameters were not significantly modified. Four (28.6%) out of 14 patients submitted to perineal levatorplasty complained of dyspareunia.

CONCLUSIONS

Our surgical results were comparable with those reported in the literature, with more than 80% of successful outcome. Preoperative clinical data and defecography were confirmed to be basic parameters in selecting patients for surgery. Colonic transit time, anal EMG, and anorectal manometry demonstrated to be useful to recognize conditions as slow colonic transit time, peripheral denervation, and reduced voluntary contraction that could lead to a less satisfactory outcome after surgery, and might benefit with a postoperative perineal rehabilitation by biofeedback and anal electrostimulations. The perineal levatorplasty is not suitable in young females, due to the risk of dyspareunia.

High sensitivity of human epidermal keratinocytes (HaCaT) to topoisomerase inhibitors

In the panorama of the numerous established cell lines, the human keratinocyte line HaCaT has a very interesting feature, having a close similarity in functional competence to normal keratinocytes. This cell line has been used in many studies as a paradigm for epidermal cells and therefore we selected HaCaT as a cell model for investigating the activity of three antitopoisomerase drugs (Camptothecin, Doxorubicin, Ciprofloxacin) on in vitro cell growth. The effect was evaluated both by a 24-h cytotoxicity test and by a 7-day antiproliferation assay, in which the cell viability was assessed by an MTT (3-(4,5-dimethyl-2-thiazolyl) 2,5-diphenil-2-H-tetrazolium bromide) test. DNA topoisomerase I was also partially purified from a nuclear extract of HaCaT cells, the level of topo I catalytic activity was measured by a pBR322 DNA relaxation assay and then the in vitro effect of antitopoisomerase drugs on the target enzyme was also assessed. The results indicated that the in vitro sensitivity of human epidermal HaCaT cells to antitopoisomerase drugs is comparable to that of many human tumour cell lines. HaCaT cells express a high level of topoisomerase I activity that is significantly inhibited by both Camptothecin and Doxorubicin and to a minor degree by Ciprofloxacin. A high correlation between the cell sensitivity to the antitopoisomerase I drug measured by the MTT test and the in vitro direct inhibition of HaCaT topoisomerase I was observed, suggesting that HaCaT cells can represent a very interesting model both for studying cellular pharmacokinetics of antineoplastic drugs on keratinocytes and for predicting possible secondary effects, exerted by these drugs on cutaneous cells, during treatment with chemotherapy.

Mutation in Serratia marcescens AmpC beta-lactamase producing high-level resistance to ceftazidime and cefpirome

Starting from a clinical isolate of Serratia marcescens that produced a chromosomally encoded AmpC beta-lactamase inducibly, we isolated by stepwise selection two laboratory mutants that showed high levels of resistance to some cephalosporins. The 98R mutant apparently overproduced the unaltered beta-lactamase constitutively, but the 520R mutant produced an altered enzyme, also constitutively. Ceftazidime and cefpirome MICs for the 520R mutant were much higher (512 and 64 microg/ml, respectively) than those for the 98R mutant (16 and 16 microg/ml, respectively). Yet the MICs of cephaloridine and piperacillin for the 520R mutant were four- to eightfold lower than those for the 98R mutant. Cloning and sequencing of the ampC alleles showed that in the 520R mutant enzyme, the Thr64 residue, about two turns away from the active-site serine, was mutated to isoleucine. This resulted in a >1,000-fold increase in the catalytic efficiency (k(cat)/K(m)) of the mutated AmpC enzyme toward ceftazidime, whereas there was a >10-fold decrease in the efficiency of the mutant enzyme toward cefazolin and cephaloridine. The outer membrane permeability of the 520R strain to cephalosporins was also less than in the 98R strain, and the alteration of the kinetic properties of the AmpC enzyme together with this difference in permeability explained quantitatively the resistance levels of both mutant strains to most agents studied.

Altered DNA-cleavage activity of topoisomerase II from WEHI-3B leukemia cells with specific resistance to ciprofloxacin

In order to investigate the mechanisms of drug resistance arising in tumor cells, we investigated the capacity of fluoroquinolones to inhibit the in vitro growth of WEHI-3B monomyelocytic leukemia cells and then we established a variant of this line (currently maintained in the absence of drug). The line, named WEHI-3B/CPX, expresses a specific resistance to ciprofloxacin (CPX; resistance index=17.3+/-2.2), and does not show cross-resistance with other fluoroquinolones, camptothecin and topoisomerase II inhibitors such as doxorubicin, etoposide and teniposide. Although a little decrease in intracellular accumulation of CPX is observed in WEHI-3B/CPX cells, these cells do not express MDR or LRP markers, and the resistance is not circumvented by verapamil. Purified nuclear extracts from WEHI-3B and WEHI-3B/CPX cells were tested for topoisomerase I catalytic activity and checking in vitro topoisomerase I sensitivity to CPX and camptothecin inhibition, but no difference was observed. As the treatment with CPX showed that the resistant cell line suffers a significantly lower number of breaks in the DNA molecule we also addressed our investigations to the topoisomerase II-dependent DNA cleavage that, in the resistant clone, was found dramatically less susceptible to be enhanced by CPX both in pre-strand and post-strand DNA passage conditions. WEHI-3B/CPX cells do not express any character of multidrug resistance and represent a rare case of specific drug resistance to CPX. The specific resistance to CPX observed in these cells is related to a functional decrease of topoisomerase II cleavage activity. It could be consequent to a decreased binding affinity of CPX for the topoisomerase II--DNA complex or to a decreased affinity or specificity of topoisomerase II for its DNA cleavage sites.

[Nosocomial infections. State of the art]

Little information exists up till now about the prevalence of nosocomial and community acquired infections in Italian hospitals. Little is known about the effects of thorough cleaning in today's hospitals. This review examines the common microorganisms associated with hospital acquired infections and their ability to survive in the hospital environment. The most frequent site of hospital acquired infections is the urinary tract, followed by surgical wounds and the upper respiratory tract. Analysis of North America and European data shows that the increase in length of stay for infected patients is the most striking of all examined costs. Improving standards of hygiene in hospitals would be a safe method to control hospital-acquired infections and their costs.

Identification of the major intestinal fatty acid transport protein

While intestinal transport systems for metabolites such as carbohydrates have been well characterized, the molecular mechanisms of fatty acid (FA) transport across the apical plasmalemma of enterocytes have remained largely unclear. Here, we show that FATP4, a member of a large family of FA transport proteins (FATPs), is expressed at high levels on the apical side of mature enterocytes in the small intestine. Further, overexpression of FATP4 in 293 cells facilitates uptake of long chain FAs with the same specificity as enterocytes, while reduction of FATP4 expression in primary enterocytes by antisense oligonucleotides inhibits FA uptake by 50%. This suggests that FATP4 is the principal fatty acid transporter in enterocytes and may constitute a novel target for antiobesity therapy.

Role of SR-4987 stromal cells in the modulation of doxorubicin toxicity to in vitro granulocyte-macrophage progenitors (CFU-GM)

Bone marrow stromal microenvironment is essential for the maintenance of the hematopoietic stem cell renewal both by cell-cell interaction and cytokine production. However, stromal cells also exhibit drug metabolizing activities and they may accumulate the drug and successively affect hematopoietic progenitors by a retarded release. Our study investigated the role of both primary culture of murine bone marrow stroma and established stromal cells (SR-4987) in modulating the "in vitro" toxic activity of Doxorubicin (DXR) against murine granulocyte-macrophage progenitors (CFU-GM). The main part of the study has been performed by a "in vitro" agar bilayer technique based on the CFU-GM assay performed over a feederlayer of stromal cells. The results suggest that bone marrow stromal cells play also an important role in decreasing the toxicity of Doxorubicin. Further SR-4987 stromal cells produce a Doxorubicin metabolite (not belonging to the series of metabolites described in literature) which is completely ineffective in inhibiting the growth of CFU-GM and the activity of topoisomerase I. Our data suggest that bone marrow stromal cells must be considered as a cell population having opposite pharmacological roles in modulating the drug toxicity on hematopoietic progenitors. In our model a mechanism of detoxification concerns the capacity of SR-4987 stromal cells to inactivate the drug. For a better prediction of drug hematotoxicity, it is very important to develop "in vitro" cell models able to discriminate between positive and negative modulation of drug toxicity that stromal cells can exert in the bone marrow microenvironment.

[Immediate postoperative respiratory complications after coronary surgery]

The influence of anesthesia, surgical procedure and special conditions of open-heart surgery upon respiratory function alterations is analyzed. Hypoxemia (present even in non-complicated open heart surgery) can be due to alveolar hypoventilation, ventilation-perfusion mismatch or shunt. The origin of atelectasias (present in 50-92% of patients) and pleural effusion (42-87%) is discussed. Phrenic nerve damage is usually secondary to thermal injury. Other less common complications are discussed. The influence of age, smoking and previous pulmonary diseases on respiratory complications is analyzed. Respiratory care after heart surgery (as time and requisites of extubations) and results of different methods (CPAP, PEEP, incentive inspirometry) are reviewed.

The active site of ICP47, a herpes simplex virus-encoded inhibitor of the major histocompatibility complex (MHC)-encoded peptide transporter associated with antigen processing (TAP), maps to the NH2-terminal 35 residues

The herpes simplex virus (HSV) immediate early protein ICP47 inhibits the transporter associated with antigen processing (TAP)-dependent peptide translocation. As a consequence, empty major histocompatibility complex (MHC) class I molecules are retained in the endoplasmic reticulum and recognition of HSV-infected cells by cytotoxic T lymphocytes is abolished. We chemically synthesized full-length ICP47 (sICP47) and show that sICP47 inhibits TAP-dependent peptide translocation in human cells. Its biological activity is indistinguishable from that of recombinant ICP47 (rICP47). By using synthetic peptides, we mapped the core sequence of ICP47 minimally required for TAP inhibition to residues 2-35. This segment is located within the region of the molecule conserved between ICP47 from HSV-1 and HSV-2. Through alanine scanning substitution we identified three segments within this region that are critical for the ability to inhibit TAP function. The interaction of ICP47 with TAP is unlikely to mimic precisely that of the transported peptides, as deduced from differential labeling of the TAP1 and TAP2 subunits using sICP47 fragments with chemical cross-linkers.

Hydrolysis of synthetic peptides by cruzipain, the major cysteine proteinase from Trypanosoma cruzi, provides evidence for self-processing and the possibility of more specific substrates for the enzyme

Two synthetic peptides, peptide G, with the sequence KEEASSAVVGGPG, consisting of the last 10 amino acid residues of the catalytic domain, plus the first 3 at the C-terminal domain, of cruzipain, and peptide R, with the sequence KEEASSAVVRGPG, were hydrolyzed by the enzyme, as shown by reversed-phase HPLC. Peptide R was the best substrate, with a Vmax/K(m) ratio 6-fold higher as compared with peptide G, in good agreement with previous studies indicating that, in small peptides, cruzipain prefers R or K at P1. The optimal pH values for hydrolysis of peptides G and R were 6.8 and 8.0, respectively. A p-nitroanilide derivative containing the P1-P3 residues, Z-VVR-pNA, was an excellent substrate for cruzipain, with a K(m) value (33 microM at pH 9.0) lower than that for Bz-PFR-pNA (66 microM). These results open the possibility of synthesizing more specific substrates and inhibitors of cruzipain.

Homologs of the Xenopus developmental gene DG42 are present in zebrafish and mouse and are involved in the synthesis of Nod-like chitin oligosaccharides during early embryogenesis

The Xenopus developmental gene DG42 is expressed during early embryonic development, between the midblastula and neurulation stages. The deduced protein sequence of Xenopus DG42 shows similarity to Rhizobium Nod C, Streptococcus Has A, and fungal chitin synthases. Previously, we found that the DG42 protein made in an in vitro transcription/translation system catalyzed synthesis of an array of chitin oligosaccharides. Here we show that cell extracts from early Xenopus and zebrafish embryos also synthesize chitooligosaccharides. cDNA fragments homologous to DG42 from zebrafish and mouse were also cloned and sequenced. Expression of these homologs was similar to that described for Xenopus based on Northern and Western blot analysis. The Xenopus anti-DG42 antibody recognized a 63-kDa protein in extracts from zebrafish embryos that followed a similar developmental expression pattern to that previously described for Xenopus. The chitin oligosaccharide synthase activity found in extracts was inactivated by a specific DG42 antibody; synthesis of hyaluronic acid (HA) was not affected under the conditions tested. Other experiments demonstrate that expression of DG42 under plasmid control in mouse 3T3 cells gives rise to chitooligosaccharide synthase activity without an increase in HA synthase level. A possible relationship between our results and those of other investigators, which show stimulation of HA synthesis by DG42 in mammalian cell culture systems, is provided by structural analyses to be published elsewhere that suggest that chitin oligosaccharides are present at the reducing ends of HA chains. Since in at least one vertebrate system hyaluronic acid formation can be inhibited by a pure chitinase, it seems possible that chitin oligosaccharides serve as primers for hyaluronic acid synthesis.

Loss of porins following carbapenem-resistance selection and adherence modification in enterobacteria

The acquired resistance to the carbapenems is frequently joined to modified expression of porins or other outer membrane (OM) structures, thus bacterial adherence, that also depends on the presence of peculiar surface structures, might theoretically be influenced. In this study the ability to adhere to Hep-2 and I-407 eukaryotic cell monolayers was assayed for two susceptible strains of Serratia marcescens, one strain of Enterobacter cloacae and one of Providencia rettgeri in comparison with that of isogenic resistant mutants selected either by carbapenems or by cephalosporins. The mutants appeared slightly less adherent than the wild type strains, however, due to the high variability of this kind of assay, the differences observed in most cases could not be considered statistically significant. The data suggest that adherence, among the factors affecting the pathogenicity of the strains, remains probably unmodified in the resistant bacterial population possibly selected by a carbapenem treatment.

Different biological conditions influencing bacterial adherence assay

Adherence of bacteria to animal cells is considered the first step in the pathogenesis of many infectious diseases. The most suitable techniques developed in vitro to check the capacity of bacteria to adhere to different tissues use monolayers of established cell lines. We studied the influence of incubation time (1, 2, 3 hours), cell substrates (Hep-2, H-407) and the number of bacteria per cell (1, 10, 100, 1000) on the adherence index (number of adherent bacteria per cell determined by microscopic count) of the fimbriated Escherichia coli 454 strain, Proteus rettgeri 25 and Enterobacter cloacae 10. The data were analyzed with different statistical methods and the results evidenced that all the conditions considered affect either the end-point of the test or the adherence index. Our observations indicate that the different methods used make it impracticable to compare many data from the literature and suggest the need to search for more homogeneity in this type of assay.

Outer membrane permeability of Serratia marcescens to meropenem and imipenem

The penetration rates of meropenem and imipenem through the outer membrane (OM) of Serratia marcescens was evaluated by the method of Zimmermann and Rosselet. To this aim, two strains of the specie were transformed with the pMON-01 plasmid DNA that carries the bla S gene from Xanthomonas maltophilia encoding for the L-1 beta-lactamase. The permeability of the transformants to cephaloridine was not affected by the presence of the plasmid. Imipenem was shown to penetrate the OM of the transformants at a rate 4- to 5-fold higher than that of meropenem and close to that of cephaloridine. Meropenem appeared more active than imipenem in inhibiting the targets as inferred from the calculated concentrations of antibiotic in the cell periplasm in the presence of MIC. The calculation of the target access index (TAI) indicated that a 20- to 50-fold decrease in permeability or increase in beta-lactamase activity would be required to significantly increase the MICs of imipenem or meropenem for these strains.

Double catheterization of the internal jugular vein for hemodialysis: indications, techniques, and clinical results

Central vascular catheters are used to access the central vascular system in both acute and chronic uremic patients undergoing hemodialysis. Among different approaches, the internal jugular vein seems to have less adverse effects. We describe our long-term experience with a two-catheter system. Percutaneous jugular vein cannulation was performed using Medcomp silicone rubber catheters. The study included 108 patients undergoing hemodialysis. One- and 2-year survival was 93 and 91%, respectively; 36 died because of unrelated causes. Blood flow rate was 284 mL/min; venous pressure at 1 year was 90 mm Hg. Complications included accidental withdrawal (6), dysfunction (4), catheter clotting (11), mediastinal hematoma (2), pneumothorax (1), and sepsis (7). Good long-term survival and a low complication rate make this system a safe and reliable method of access for long-term hemodialysis.

[Phakomatosis in childhood. Clinical and instrumental observations of 11 cases]

Taking the institution of the Italian Neuroectodermosis Register (Fois, April 1987) as a starting point, the Authors reviewed their own case-records, including six cases of neurofibromatosis and five cases of tuberous sclerosis, observed during the period 1982/88, and stress the need for early diagnosis (unfortunately often neglected), indispensable both for an effective prevention of any pathological involvement and for precise genetic counselling, susceptible of further improvements thanks to more and more advanced diagnostic techniques.

Imipenem- and meropenem-resistant mutants of Enterobacter cloacae and Proteus rettgeri lack porins

Carbapenems such as imipenem and meropenem are not rapidly hydrolyzed by commonly occurring beta-lactamases. Nevertheless, it was possible, by mutagenesis and selection, to isolate mutant strains of Enterobacter cloacae and Proteus rettgeri that are highly resistant to meropenem and imipenem. Two alterations were noted in the E. cloacae mutants. First, the mutant strains appeared to be strongly derepressed in the production of beta-lactamases, which reached a very high level when the strains were grown in the presence of imipenem. Second, these mutants were deficient in the production of nonspecific porins, as judged by the pattern of outer membrane proteins as well as by reconstitution assays of permeability. As with most porin-deficient mutants, their cultures were unstable, and their cultivation in the absence of carbapenems rapidly led to an overgrowth of porin-producing revertants. Analysis of the data suggests that the synergism between the lowered outer membrane permeability and the slow but significant hydrolysis of carbapenems by the overproduced enzymes can explain the resistance phenotypes quantitatively, although the possibility of alteration of the target cannot be excluded at present. With P. rettgeri mutants, there was no indication of further derepression of beta-lactamase, but the enzyme hydrolyzed imipenem much more efficiently than the E. cloacae enzyme did. In addition, the major porin was absent in one mutant strain. These results suggest that a major factor for the carbapenem resistance of these enteric bacteria is the porin deficiency, and this conclusion forms a contrast to the situation in Pseudomonas aeruginosa, in which the most prevalent class of imipenem-resistant mutants appears to lack the specific channel protein D2 yet retains the major nonspecific porin F.

[Probable ADH inappropriate secretion syndrome in varicella]

Varicella (chickenpox) is sometimes associated with serious complications characterized bp changeable frequency in different ages. We describe a case of varicella with contemporary presence of several complications: serious impetigo , conjunctivitis, pneumonia, hepato-encephalic disease (probable Reye syndrome). This case is interesting because after adequate rehydration and normalization of electrolytes we registered a remarkable fall of plasmatic sodium and chloride as a result of hemodilution probably due to a syndrome of inappropriate secretion of antidiuretic hormone, confirmed by values of plasmatic and urinary osmolarity and of urinary electrolytes.

Antibacterial activity of tigemonam dicholate (SQ 30836) and interaction with beta-lactamases of gram-negative bacteria

SQ 30836 is an orally absorbed salt of tigemonam, a new monobactam similar to aztreonam in structure and microbiologic properties. When assayed against 400 clinical isolates, tigemonam's activity was similar to that of aztreonam and carumonam. It was highly effective against Enterobacteriaceae but showed poor activity against gram-positive organisms. It inhibited 90% of Escherichia coli, Klebsiella, Shigella, Yersinia, Proteus, Providencia, and Morganella strains at 0.5 micrograms/mL or less, and all Salmonella and Hafnia strains at 1 micrograms/mL or less. Citrobacter, Enterobacter, and Serratia strains were less susceptible (minimum inhibitory concentrations [MIC30] of 2, 32, and 8 micrograms/mL respectively). The activity of the new compound against Enterobacteriaceae is comparable with and often higher than that of third-generation cephalosporins and oral comparison compounds. In contrast to aztreonam, tigemonam had minimal activity against Pseudomonas sp and glucose nonfermenting gram-negative bacteria. Data suggest that poor penetration through the outer membranes of Pseudomonas sp may be responsible for this failure. Tigemonam was stable to hydrolysis by plasmid-mediated and chromosomal beta-lactamases. It was more stable than aztreonam to hydrolysis by the Kl enzyme of Klebsiella and by the Proteus vulgaris beta-lactamase. Also, measurement of the IC50 (concentration of inhibitor able to reduce the activity of the enzyme by 59%) showed that tigemonam has less affinity than aztreonam for class I cephalosporinases. However, only levels of beta-lactamase, not hydrolysis rates or affinity, correlated to MICs of the two monobactams for the resistant Enterobacter and Citrobacter strains.

Further characterization and partial amino acid sequence of a cysteine proteinase from Trypanosoma cruzi

A cysteine proteinase from epimastigotes of Trypanosoma cruzi, Tul 2 stock, has been purified to homogeneity from cell-free extracts obtained by freezing and thawing, by a procedure involving ammonium sulfate fractionation, DEAE-Sephacel chromatography, and gel filtration on Sephadex G-200; when necessary, further purification was attained by fast protein liquid chromatography on Mono Q and Superose 6 columns. The purified enzyme was strongly inhibited by leupeptin, antipain and chymostatin (I50 values of 0.25, 0.75 and 1 microM, respectively), little inhibited by elastatinal, and unaffected by pepstatin A. The enzyme is a glycoprotein, as shown by binding to ConA-Sepharose and elution with alpha-methyl-D-mannopyranoside and alpha-methyl-D-glucopyranoside. Partial amino acid sequences were obtained from the N-terminal end (32 amino acids) of the carbamidomethylated enzyme, and from a tryptic peptide (14 amino acids) of the pyridylethylated enzyme. Both regions show considerable homology with papain and some cathepsins, such as cathepsin L, thus showing that the enzyme belongs to the cysteine proteinase family.

Carumonam's in-vitro activity against gram-negative bacteria and its stability to their beta-lactamases

The in vitro activity of the novel monobactam carumonam (RO17-2301) was evaluated on 311 gram-negative clinical isolates in comparison to aztreonam, cefotaxime, ceftazidime, cefotetan and ceftriaxone. Carumonam showed an antibacterial potency equal to or higher than any other reference compound; in particular it was the most effective against Proteus indole positive and Klebsiella sp. Its antipseudomonal activity was comparable to that of ceftazidime and it showed, together with aztreonam, the highest activity against the Citrobacter, Enterobacter and Escherichia coli isolates. The minimal inhibitory concentrations performed on permeability altered organisms indicated that carumonam has a penetration rate comparable to aztreonam and higher than cefotetan and ceftriaxone. Carumonam demonstrated excellent stability to chromosomal and plasmid-mediated beta-lactamases and that correlated with its antibacterial activity against the producing strains and inoculum size effect.

Itraconazole in pityriasis versicolor: ultrastructural changes in Malassezia furfur produced during treatment

Twenty-eight patients with pityriasis versicolor were treated orally with 200 mg of itraconazole per day in an open, randomized comparison of five-day and seven-day treatment regimens. The morphologic changes in Malassezia furfur produced by treatment were confirmed by studies with transmission and scanning electron microscopy. The clinical results showed that seven days of treatment were more effective than five days. Transmission electron microscopy revealed cytopathic changes in the fungus at the end of treatment, intracellular necrosis being complete within seven to 28 days. Cell-surface alterations detected by scanning electron microscopy developed more slowly--maximal changes were observed 14 days after the beginning of treatment. One patient developed nausea during treatment; no other adverse effects were attributed to the drug.

Analysis of spontaneous deletion mutants of satellite bacteriophage P4

Spontaneous deletion mutants of satellite bacteriophage P4 have been isolated and characterized. All of the deletions analyzed that were between 850 and 1,700 base pairs long are within the region nonessential for P4 lytic development; some of them cover the cII or the gop locus.

Isolation and partial characterization of temperature bacteriophages from enteropathogenic strains of Escherichia coli 0111:K58

We report studies on ten strains of Escherichia coli 0111:K58 isolated from children with acute diarrhea. Our results show that these E. coli strains do not produce the pathogenic factors of enterotoxic E. coli (ETEC) and are lysogenic for phages belonging to two groups that differ for host range, kinetics of thermal inactivation, antigenicity and morphology. These data support the hypothesis that these phages may in vivo contribute to reduction of the number of common E. coli strains by lytic infection favouring the development of the enteropathogenic strain of E. coli.

[Bactericidal activity of octophene]

In this study the bactericidal activity of Clofoctol has been evaluated by "in vitro" technique against gram-positive against gram-positive microorganisms clinically isolated. The results show that MIC of Clofoctol is very close to its bactericidal activity, which could therefore be retained as its main activity. The MBC recovered was 1-8 mcg/ml against strains of Staphylococcus aureus and 2-8 mcg/ml against Streptococcus pyogenes, while the bactericidal activity against Staphylococcus aureus, evaluated at M.B.C., was recovered after 30'.

[Gonadal involvement in the Schonlein-Henoch syndrome]

The authors report a case of testicular involvement in the Henoch-Schönlein's purpura, in order to call attention on the problem of an affection which has sometimes an acute onset and may therefore undergo a useless explorative surgical intervention. With the help of the existing literature, they define the pathological feature and point out the feasibility of a differential diagnosis when looking for the usually observed involvements (skin, joints, kidney, ecc.), associated with H.S. syndrome, in an accentuated or just slightly evident way, as in the presently described case.

Origin of glycosylated hemoglobin A1 in chronic renal failure

In chronic renal failure both HbA1 and HbA1c levels have been reported to be elevated. In order to investigate the causes of such increase we measured HbA1 (cation-exchange chromatography), blood urea nitrogen, arterial blood pH, plasma bicarbonate, phosphatemia, serum iron and serum ferritin before dialysis in 60 uremic patients receiving long term hemodialysis. The increased levels of HbA1 do not correlate with glucose intolerance, phosphatemia, blood urea nitrogen, time averaged concentration of urea, serum iron and serum ferritin. On the contrary the presence of a highly significant correlation between HbA1 and arterial blood pH (p less than 0.001) and between HbA1 and plasma bicarbonate (p less than 0.001) seems to emphasize a major role for acidosis in increasing the HbA1 levels in uremic patients on long term hemodialysis.

Mutagenicity of diphenylhydantoin and some of its metabolites towards salmonella typhimurium strains

The mutagenicities of 5,5-diphenylhydantoin (DPH) and its major metabolite, 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) were tested in vitro using different Salmonella strains (TA1535, TA100, TA1537, TA1538, TA98). Experiments were carried out at various concentrations in the absence and in the presence of an activating system consisting of hepatic S9 fraction from control rats and from rats pretreated with phenobarbital (PB), beta-naphthoflavone (BNF), 3-methylcholanthrene (3-MC) and Aroclor 1254 (PCB). DPH slightly increased the number of revertants per plate only after incubations with TA1538 in the presence of the S9 fraction from the liver of 3-MC- and PCB-pretreated animals. A similar but more significant frameshift mutation was observed for HPPH on both TA98 and TA1538 strains and in conditions of metabolic activation by the liver microsomal fractions of rats after pretreatment with BNF, 3-MC and especially PCB. Parallel experiments on the metabolism of DPH to HPPH and of HPPH to the catechol derivative in vitro support the hypothesis of an involvement of epoxide intermediates in the mutagenic activity of DPH.

Simple methods for nutritional assessment in hemodialyzed patients

Uremic patients undergoing hemodialysis are often catabolic and malnourished. To treat malnutrition effectively, a preliminary nutritional assessment is needed. Available techniques should enable the clinician to readily detect the presence of malnutrition and to follow the response to nutritional therapy. In a group of chronic uremic patients undergoing maintenance hemodialysis, the authors evaluated the nutritional status with the following indices: 1) assessment of the somatic fat and protein compartments by means of anthropometric measurements (weight/height ratio, triceps and subscapular skinfold thickness, and arm muscle circumference); 2) assessment of the visceral protein compartment (serum total protein, albumin, transferrin, pseudocholinesterase, C3, and immunoglobulin content); 3) assessment of cell-mediated immunity by means of skin tests ("skin window," PPD and phytohemagglutinin) and blood lymphocyte content; and 4) assessment of the dietary intake of nutrients with dietary diaries. Anthropometric indices, serum protein content (except immunoglobulins), and the immune response was generally lower than in normal subjects, suggesting a mixed marasmus-like and kwashiorkor-like pattern of protein-calorie malnutrition. The protein intake was normal, whereas the energy intake tended to be low. Protein intake was significantly correlated with the predialysis serum urea nitrogen. Due to the difficulties in improving oral energy intake and the negative nitrogen balance reported during the days of dialysis therapy, patients were given intravenous supplements of essential or essential and nonessential amino acids for 2 months. The effects of this short-term supplementation were limited.