Bronchoalveolar lavage fluid characteristics and outcomes of invasively mechanically ventilated patients with COVID-19 pneumonia in Genoa, Italy

BACKGROUND

The primary objective of the study is to describe the cellular characteristics of bronchoalveolar lavage fluid (BALF) of COVID-19 patients requiring invasive mechanical ventilation; the secondary outcome is to describe BALF findings between survivors vs non-survivors.

MATERIALS AND METHODS

Patients positive for SARS-CoV-2 RT PCR, admitted to ICU between March and April 2020 were enrolled. At ICU admission, BALF were analyzed by flow cytometry. Univariate, multivariate and Spearman correlation analyses were performed.

RESULTS

Sixty-four patients were enrolled, median age of 64 years (IQR 58-69). The majority cells in the BALF were neutrophils (70%, IQR 37.5-90.5) and macrophages (27%, IQR 7-49) while a minority were lymphocytes, 1%, TCD3+ 92% (IQR 82-95). The ICU mortality was 32.8%. Non-survivors had a significantly older age (p = 0.033) and peripheral lymphocytes (p = 0.012) were lower compared to the survivors. At multivariate analysis the percentage of macrophages in the BALF correlated with poor outcome (OR 1.336, CI95% 1.014-1.759, p = 0.039).

CONCLUSIONS

In critically ill patients, BALF cellularity is mainly composed of neutrophils and macrophages. The macrophages percentage in the BALF at ICU admittance correlated with higher ICU mortality. The lack of lymphocytes in BALF could partly explain a reduced anti-viral response.

Extensive activation, tissue trafficking, turnover and functional impairment of NK cells in COVID-19 patients at disease onset associates with subsequent disease severity

The SARS-CoV-2 infection causes severe respiratory involvement (COVID-19) in 5-20% of patients through initial immune derangement, followed by intense cytokine production and vascular leakage. Evidence of immune involvement point to the participation of T, B, and NK cells in the lack of control of virus replication leading to COVID-19. NK cells contribute to early phases of virus control and to the regulation of adaptive responses. The precise mechanism of NK cell dysregulation is poorly understood, with little information on tissue margination or turnover. We investigated these aspects by multiparameter flow cytometry in a cohort of 28 patients hospitalized with early COVID-19. Relevant decreases in CD56brightCD16+/- NK subsets were detected, with a shift of circulating NK cells toward more mature CD56dimCD16+KIR+NKG2A+ and "memory" KIR+CD57+CD85j+ cells with increased inhibitory NKG2A and KIR molecules. Impaired cytotoxicity and IFN-γ production were associated with conserved expression of natural cytotoxicity receptors and perforin. Moreover, intense NK cell activation with increased HLA-DR and CD69 expression was associated with the circulation of CD69+CD103+ CXCR6+ tissue-resident NK cells and of CD34+DNAM-1brightCXCR4+ inflammatory precursors to mature functional NK cells. Severe disease trajectories were directly associated with the proportion of CD34+DNAM-1brightCXCR4+ precursors and inversely associated with the proportion of NKG2D+ and of CD103+ NK cells. Intense NK cell activation and trafficking to and from tissues occurs early in COVID-19, and is associated with subsequent disease progression, providing an insight into the mechanism of clinical deterioration. Strategies to positively manipulate tissue-resident NK cell responses may provide advantages to future therapeutic and vaccine approaches.

Clinical characteristics, management and in-hospital mortality of patients with coronavirus disease 2019 in Genoa, Italy

OBJECTIVES

To describe clinical characteristics, management and outcome of individuals with coronavirus disease 2019 (COVID-19); and to evaluate risk factors for all-cause in-hospital mortality.

METHODS

This retrospective study from a University tertiary care hospital in northern Italy, included hospitalized adult patients with a diagnosis of COVID-19 between 25 February 2020 and 25 March 2020.

RESULTS

Overall, 317 individuals were enrolled. Their median age was 71 years and 67.2% were male (213/317). The most common underlying diseases were hypertension (149/317; 47.0%), cardiovascular disease (63/317; 19.9%) and diabetes (49/317; 15.5%). Common symptoms at the time of COVID-19 diagnosis included fever (285/317; 89.9%), shortness of breath (167/317; 52.7%) and dry cough (156/317; 49.2%). An 'atypical' presentation including at least one among mental confusion, diarrhoea or nausea and vomiting was observed in 53/317 patients (16.7%). Hypokalaemia occurred in 25.8% (78/302) and 18.5% (56/303) had acute kidney injury. During hospitalization, 111/317 patients (35.0%) received non-invasive respiratory support, 65/317 (20.5%) were admitted to the intensive care unit (ICU) and 60/317 (18.5%) required invasive mechanical ventilation. All-cause in-hospital mortality, assessed in 275 patients, was 43.6% (120/275). On multivariable analysis, age (per-year increase OR 1.07; 95% CI 1.04-1.10; p < 0.001), cardiovascular disease (OR 2.58; 95% CI 1.07-6.25; p 0.03), and C-reactive protein levels (per-point increase OR 1.009; 95% CI 1.004-1.014; p 0.001) were independent risk factors for all-cause in-hospital mortality.

CONCLUSIONS

COVID-19 mainly affected elderly patients with predisposing conditions and caused severe illness, frequently requiring non-invasive respiratory support or ICU admission. Despite supportive care, COVID-19 remains associated with a substantial risk of all-cause in-hospital mortality.

sodC genes expression in Escherichia coli O157:H7 strains

INTRODUCTION

E. coli O157:H7 has three sodC genes encoding for Cu,Zn superoxide dismutase. We evaluated the expression of chromosomal sodC in distinct phases of growth in different strains, and we examined the mutual capability of chromosomal and prophagic genes to influence their expression.

METHODS

We used One Step real-time RT-PCR technology to study the expression of sodC genes in several E. coli strains.

RESULTS

In three of four analysed E. coli O157:H7 strains the chromosomal sodC gene was more expressed in exponential phase than in stationary phase, unlike it occurs in the E. coli K12 strain. The expression of the chromosomal gene was always higher than that of the prophagic copies. Deletion of prophagic or chromosomal sodC genes had no effect on the expression of the residual gene.

CONCLUSION

Our study highlights an inherent variability in number and level of expression of sodC genes in E. coli O157:H7 strain.

A study on prophagic and chromosomal sodC genes involvement in Escherichia coli O157:H7 biofilm formation and biofilm resistance to H2O2

INTRODUCTION

Escherichia coli O157:H7 possesses one chromosomal and two prophagic sodC genes encoding for Cu,Zn superoxide dismutases. We evaluated the contribution of sodC genes in biofilm formation and its resistance to hydrogen peroxide.

METHODS

The biofilm of sodC deletion mutants has been studied, in presence or absence of hydrogen peroxide, by crystal violet in 96-well plates and Scanning Electron Microscopy on glass coverslips.

RESULTS

Deletion of prophagic sodC genes had no effect on biofilm construction, in contrast to the chromosomal gene deletion. Hydrogen peroxide treatment showed higher cell mortality and morphological alterations in sodC deletion mutants respect to wild type. These effects were related to the biofilm development stage.

CONCLUSION

The role of the three SodCs is not redundant in biofilm formation and the resistance to oxidative damage. The stage of biofilm development is a crucial factor for an effective sanitization.

Prevalence and Risk Factors for Significant Liver Fibrosis in Patients with HIV Infection

AIM

The aim of the present study was the evaluation of liver fibrosis in a population of patients monoinfected with HIV using the transient liver elastography (FibroScan) method.

PATIENTS AND METHODS

A total of 228 consecutive patients with HIV were evaluated: 80 (35.09%) were HIV-1 monoinfected and 148 (64.91%) (HIV)/hepatitis C virus (HCV) co-infected. Echoic liver diagnosis was also performed.

RESULTS

F2 Metavir-score fibrosis or higher was found to be associated with drug addiction, alanine aminotransferase >80 UI/l, cluster of differentiation 4 (CD4(+)) T lymphocytes nadir <200 copies/ml, therapy duration, protease inhibitor (PI)-based antiretroviral regimen, HCV infection and AIDS diagnosis. Multivariate analysis highlighted a significant association with drug addiction, AIDS diagnosis, therapy duration and HCV co-infection. Echoic liver diagnosis showed signs of damage among 43.75% of monoinfected patients vs. 62.84% among co-infected.

CONCLUSION

Monoinfected patients showed pathological signs both at liver ultrasonography and at FibroScan. In the onset of these changes, a significant role by HIV disease and duration of therapy is observed.

Phalangeal quantitative ultrasound: cheaper methods for screening and follow-up of bone pathologies in HIV-infected women?

This study estimated the prevalence of bone pathologies in a cohort of HIV-infected women in comparison with a cohort of HIV-negative women. Bone mineral density was measured by phalangeal quantitative ultrasound (AD-SoS: amplitude- dependent speed of sound; UBPI: ultrasound bone profile index). Risk of fracture, expressed by UBPI, was considered for value <0.39. Comparisons between groups and multivariate analyses were carried out using an ANOVA model. Correlations were evaluated using the Pearson correlation coefficient. Osteopenia and osteoporosis were present in 34.4% and 2% of patients, respectively. UBPI was pathologic in 5.7%. In a multivariate linear regression model significant correlations were found between AD-SoS z-score, duration of HIV-infection and BMI value. We also compared our cohort with 499 HIV-negative women as a historical control group of healthy subjects. AdSoS (2100 versus 2070 m/s) and UBPI (0.89 versus 0.74) were lower in HIV-infected women (p<0.001). Significant differences were also found in T-score values (p = 0.0013). These data show a high prevalence of bone diseases in women with HIV infection, correlated with duration of HIV-infection and BMI values. This non-invasive technique opens up new interesting perspectives, suggesting a possible use for bone mass screening in HIV-infected women.

Nevirapine-based regimens in routine clinical settings: results from a large Italian cohort of HIV-1 infected adults

We assessed the safety and efficacy of different nevirapine-based regimens in patients starting this drug in a large cohort of Caucasian subjects during the 1999-2007 periods.

METHODS

A retrospective database review of all patients receiving nevirapine was performed; clinical, biochemical (hepatic and metabolic profiles), immuno-virological parameters were evaluated in the overall population and in different subgroups (according to gender, therapy-experience and HBV/HCV co-infection). We determined risk factors related to dyslipidemia development and to nevirapine interruption within 1 year.

RESULTS

We evaluated 277 patients; 58 (20.9%) were naïve, 180 (65%) females and 137 (49.5%) HBV/HCV co-infected. After 48 weeks, 73.6% patients continued antiretroviral regimens. Among these, nevirapine showed little hepatic and metabolic impact, as well as good immuno-virological outcome despite sex, drug experience and co-infection. Factors related to development of dyslipidemia were higher in total cholesterol, female gender with high CD4 count and male gender with low CD4 count (p<0.05). Factors related to discontinue nevirapine were age and HBV/HCV co-infection (p<0.05).

CONCLUSIONS

We observed a high rate of discontinuation probably because of the special composition of our population (huge proportion of women and co-infected individuals). Nevertheless, nevirapine was a well-tolerated drug with a favorable impact on hepatic, metabolic and immuno-virological parameters in all the analyzed subgroups.

Role of ZnuABC and ZinT in Escherichia coli O157:H7 zinc acquisition and interaction with epithelial cells

BACKGROUND

Zinc is an essential element for all living cells. Recent studies have shown that the ZnuABC zinc uptake system significantly contributes to the ability of several pathogens to multiply in the infected host and cause disease, suggesting that zinc is scarcely available within different tissues of the host. To better understand the role of zinc in bacterial pathogenicity, we have undertaken a functional characterization of the role of the ZnuABC-mediated zinc uptake pathway in enterohemorrhagic Escherichia coli O157:H7.

RESULTS

In this work we have analyzed the expression and the role in metal uptake of ZnuA, the periplasmic component of the ZnuABC transporter, and of ZinT, another periplasmic protein which has been shown to contribute to zinc recruitment. We report that the expression of zinT and znuA, regulated by Zur, is induced in zinc-poor media, and that inactivation of either of the genes significantly decreases E. coli O157:H7 ability to grow in zinc depleted media. We also demonstrate that ZinT and ZnuA have not a redundant function in zinc homeostasis, as the role of ZinT is subordinated to the presence of ZnuA. Moreover, we have found that znuA and zinT are strongly induced in bacteria adhering to cultured epithelial cells and that lack of ZnuA affects the adhesion ability. In addition we have found that a fraction of apo-ZinT can be secreted outside the cell where the protein might sequester environmental zinc, inducing a condition of metal starvation in surrounding cells.

CONCLUSIONS

The here reported results demonstrate that ZnuABC plays a critical role in zinc uptake also in E. coli O157:H7 and that ZinT contributes to the ZnuA-mediated recruitment of zinc in the periplasmic space. Full functionality of the zinc import apparatus is required to facilitate bacterial adhesion to epithelial cells, indicating that the microbial ability to compete with the host cells for zinc binding is critical to establish successful infections. The observation that ZinT can be secreted when it is in the apo-form suggests that its presence in the extracellular environment may somehow contribute to metal uptake or facilitate bacterial colonization of the intestinal epithelia.

Tigecycline use in serious nosocomial infections: a drug use evaluation

Background

Tigecycline is a novel antibiotic with activity against multidrug resistant bacteria. The aim of this study was to assess the efficacy of tigecycline use in serious hospital-acquired infections (HAI)

Case presentation

Prospective observational study of tigecycline use was conducted in a 1500 beds university hospital. From January 1, 2007 and January 31, 2010, 207 pts were treated with tigecycline for the following indications: intra-abdominal, pneumonia, bloodstream and complicated skin and soft tissue infections and febrile neutropenia. The therapy was targeted in 130/207 (63%) and empirical in 77/207 (37%) patients. All bacteria treated were susceptible to tigecycline. Median duration of tigecycline therapy was 13 days (range, 6-28). Clinical success was obtained in 151/207 (73%) cases, with the highest success rate recorded in intra-abdominal infections [81/99 (82%)]. Microbiological success was achieved in 100/129 (78%) treated patients. Adverse clinical events were seen in 16/207 patients (7.7%):

Conclusions

Considering the lack of data on tigecycline for critically ill patients, we think that the reported data of our clinical experience despite some limitations can be useful for clinicians.

Current status of newer carbapenems

OBJECTIVES

Beta-lactam antibiotics represent the most commonly prescribed antibacterial agents. Since many bacteria have developed resistance to older agents, new beta-lactams have been introduced constantly. In the late 1970s, a new class of exceptionally broad-spectrum beta-lactams, the carbapenems, was identified. The carbapenems, such as the most popular imipenem and meropenem, have the widest spectra of antibacterial activity of all the beta-lactams and provide excellent coverage of many gram-negative and gram-positive aerobic and anaerobic bacteria. Despite the wide antibacterial spectrum, the carbapenems globally lack activity against Enterococcus faecium, methicillin-resistant Staphylococcus aureus (MRSA) and Stenotrophomonas maltophilia.

METHODS

We reviewed the principal characteristics of the novel carbapenems and their clinical implications.

RESULTS AND CONCLUSIONS

We included in our review: ertapenem, biapenem, panipenem, doripenem, tebipenem pivoxil and tomopenem.

Drug treatment for multidrug-resistant Acinetobacter baumannii infections

Acinetobacter baumannii has emerged in the last decades as a major cause of healthcare-associated infections and nosocomial outbreaks. Multidrug-resistant (MDR) A. baumannii is a rapidly emerging pathogen in healthcare settings, where it causes infections that include bacteremia, pneumonia, meningitis, and urinary tract and wound infections. Antimicrobial resistance poses great limits for therapeutic options in infected patients, especially if the isolates are resistant to the carbapenems. Other therapeutic options include sulbactam, aminoglycosides, polymixyns and tigecycline. The discovery of new therapies coupled with the development of controlled clinical trial antibiotic testing combinations and the prevention of transmission of MDR Acinetobacter infection are essential to face this important hospital problem.

Regulatory and structural properties differentiating the chromosomal and the bacteriophage-associated Escherichia coli O157:H7 Cu, Zn superoxide dismutases

Background

Highly virulent enterohemorrhagic Escherichia coli O157:H7 strains possess three sodC genes encoding for periplasmic Cu, Zn superoxide dismutases: sodC, which is identical to the gene present in non-pathogenic E. coli strains, and sodC-F1 and sodC-F2, two nearly identical genes located within lambdoid prophage sequences. The significance of this apparent sodC redundancy in E. coli O157:H7 has not yet been investigated.

Results

We report that strains deleted of one or more sodC genes are less resistant than the wild type strain to a challenge with hydrogen peroxide, thus confirming their involvement in the bacterial antioxidant apparatus. To understand if the different sodC genes have truly overlapping functions, we have carried out a comparison of the functional, structural and regulatory properties of the various E. coli O157:H7 SodC enzymes. We have found that the chromosomal and prophagic sodC genes are differentially regulated in vitro. sodC is exclusively expressed in aerobic cultures grown to the stationary phase. In contrast, sodC-F1 and sodC-F2 are expressed also in the logarithmic phase and in anaerobic cultures. Moreover, the abundance of SodC-F1/SodC-F2 increases with respect to that of SodC in bacteria recovered from infected Caco-2 cells, suggesting higher expression/stability of SodC-F1/SodC-F2 in intracellular environments. This observation correlates with the properties of the proteins. In fact, monomeric SodC and dimeric SodC-F1/SodC-F2 are characterized by sharp differences in catalytic activity, metal affinity, protease resistance and stability.

Conclusion

Our data show that the chromosomal and bacteriophage-associated E. coli O157:H7 sodC genes have different regulatory properties and encode for proteins with distinct structural/functional features, suggesting that they likely play distinctive roles in bacterial protection from reactive oxygen species. In particular, dimeric SodC-F1 and SodC-F2 possess physico-chemical properties which make these enzymes more suitable than SodC to resist the harsh environmental conditions which are encountered by bacteria within the infected host.

Evaluation of insulin resistance in a cohort of HIV-infected youth

OBJECTIVE

Metabolic abnormalities, including impairment of glucose homeostasis, have been well characterized in HIV-infected patients. In contrast to adults, insulin resistance and diabetes mellitus appear to be relatively uncommon finding in youth.

DESIGN

We assessed insulin resistance, and associated risk factors, in a population of vertically HIV-infected children and young adults, when compared with a control population of healthy children.

METHODS

At the time of enrolment, weeks of pregnancy, birth weight, sex, age, weight, height, body mass index (BMI), pubertal stages, CDC classification, blood pressure, clinical lipodystrophy, hepatitis B or C co-infection, antiretroviral therapy, CD4 T lymphocyte counts, and HIV-RNA levels were recorded. Fasting plasma glucose and insulin levels and homeostatic model assessment-insulin resistance (HOMA-IR) were determined. These parameters were compared between HIV patients and healthy controls with multivariate analyses.

RESULTS

Fasting insulin levels (OR=1.21, P<0.001) and glycemia (OR=0.89, P<0.001) were significantly different between HIV-infected patients and controls. Antiretroviral therapy duration (r=0.281, P<0.05), triglyceride levels (r=0.286, P<0.05), age (r=0.299, P<0.05), and BMI SDS (r=0.485, P<0.001) were significant predictor variables of insulin resistance, expressed as HOMA-IR. Moreover, clinical lipodystrophy seems to be strongly correlated to glycemia (P<0.05), triglyceride levels (P<0.05), serum insulin levels (P<0.001), HOMA-IR (P<0.05), and also with therapy duration (P<0.05).

CONCLUSIONS

Both HIV infection and antiretroviral therapy demonstrate differential effects on glucose metabolism in HIV-infected children. Targeted prevention of insulin resistance and diabetes mellitus in HIV-infected children and young adults is needed in order to avoid the associated long-term complications that would otherwise occur, given the improvement in life expectancy of HIV-infected individuals.

Vibrio cholerae periplasmic superoxide dismutase: isolation of the gene and overexpression of the protein

Superoxide dismutases are ubiquitous enzymes which play an important role in protecting cells against oxidative damage and which have also been shown to contribute to the pathogenicity of many bacterial species. Here we demonstrate that Vibrio cholerae, the causative agent of cholerae, expresses an active periplasmic Cu,Zn superoxide dismutase. Moreover, we have set up an expression system yielding large amounts of V. cholerae recombinant Cu,Zn superoxide dismutase in the periplasm of Escherichia coli and a procedure to obtain the enzyme in a highly purified form. Unlike the bovine enzyme, V. cholerae Cu,Zn superoxide dismutase has been proved to be highly resistant to inactivation by hydrogen peroxide. This property, which appears to be common to other bacterial enzymes of this class, might improve the ability of Cu,Zn superoxide dismutase to protect bacteria against the reactive oxygen species produced by phagocytes.

Mouse spermine oxidase: a model of the catalytic cycle and its inhibition by N,N1-bis(2,3-butadienyl)-1,4-butanediamine

Spermine oxidase (SMO) is a recently described flavoenzyme belonging to the class of polyamine oxidases (PAOs) and participating in the polyamine metabolism in animal cells. In this paper we describe the expression, purification, and characterization of the catalytic properties of a recombinant mouse SMO (mSMO). The purified enzyme has absorbance peaks at 457nm (epsilon=11mM(-1)cm(-1)) and 378nm, shows a molecular mass of approximately 63kDa, and has K(m) and k(cat) values of 170microM and 4.8s(-1), using spermine as substrate; it is unable to oxidize other free or acetylated polyamines. The mechanism-based PAO inhibitor N,N(1)-bis(2,3-butadienyl)-1,4-butanediamine (MDL72,527) acts as a competitive inhibitor of mSMO, with an apparent dissociation constant K(i)=63microM. If incubated for longer times, MDL72,527 yields irreversible inhibition of the enzyme with a half-life of 15min at 100microM MDL72,527. The mMSO catalytic mechanism, investigated by stopped flow, is consistent with a simple four-step kinetic scheme.

Distinctive functional features in prokaryotic and eukaryotic Cu,Zn superoxide dismutases

Bacterial and eukaryotic Cu,Zn superoxide dismutases show remarkable differences in the active site region and in their quaternary structure organization. We report here a functional comparison between four Cu,Zn superoxide dismutases from Gram-negative bacteria and the eukaryotic bovine enzyme. Our data indicate that bacterial dimeric variants are characterized by catalytic rates higher than that of the bovine enzyme, probably due to the solvent accessibility of their active site. Prokaryotic Cu,Zn superoxide dismutases also show higher resistance to hydrogen peroxide inactivation and lower HCO3- -dependent peroxidative activity. Moreover, unlike the eukaryotic enzyme, all bacterial variants are susceptible to inactivation by chelating agents and show variable sensitivity to proteolytic attack, with the E. coli monomeric enzyme showing higher rates of inactivation by EDTA and proteinase K. We suggest that differences between individual bacterial variants could be due to the influence of modifications at the dimer interface on the enzyme conformational flexibility.

Virulence properties of type VII Streptococcus agalactiae (group B streptococci) and immunochemical analysis of capsular type polysaccharide

Strains of a new polysaccharide type of group B streptococci (GBS), type VII, have been isolated from human carriers and invasive infections. Some of these strains bear the protein antigen c or R, as do other GBS serotypes. The capsular type polysaccharide is sialylated and this residue is involved in the immunodeterminant structure. All type VII strains examined were virulent in CD-1 mice; the LD50 after intraperitoneal (i.p.) challenge was 4.57 (SD 0.12) x10(7) cfu for the reference strain and 5.49 (SD 1.5) x10(7) cfu for clinical isolates. A particular feature of this serotype was the ability to induce septic arthritis not only when injected intravenously (i.v.), but also when injected i.p. Rabbit antiserum against the capsular type VII polysaccharide exhibited opsonic activity in a phagocytosis assay and protective activity against infection.

Inhibition of melanoma pulmonary metastasis by methylxanthines due to decreased invasion and proliferation

Theophylline- and caffeine-treated B16-F10 cells exhibited low adhesion to laminin/collagen type IV and reduced invasion through Matrigel in an in vitro assay. In contrast, theobromine appeared ineffective. When young adult C57BL/6 mice were injected intravenously with theophylline-treated B16-F10 cells, the number of surface lung tumours was markedly reduced. Densitometric analyses performed on digitalized microscopic images of histological sections of lung were used to estimate the frequency (number of lung foci; NLF) and the size (average area of metastatic foci; AMF) of the resulting tumour foci. These parameters were correlated to the proliferation (AMF) and invasion (NLF) of melanoma cells in vivo. The data showed a similar theophylline-induced decrease in the AMF and NLF values (71%, P < 0.01). Caffeine treatment produced a more pronounced decrease in the AMF (61%, P < 0.01) than in the NLF (25%, P < 0.01). To our knowledge, this is the first demonstration that theophylline and caffeine possess the capacity to inhibit not only cell proliferation, but also the metastatic behaviour of melanoma cancer cells.

Interferon alpha2 recombinant and epidermal growth factor modulate proliferation and hypusine synthesis in human epidermoid cancer KB cells

We previously found that interferon alpha2 recombinant (IFNalpha) increases the expression of epidermal growth factor receptor (EGF-R) in the human epidermoid cancer KB cell line. Here we report the effects of IFNalpha and epidermal growth factor (EGF) on KB cell cycle kinetics. IFNalpha (1000 i.u./ml) for 48 h decreased the S-phase fraction and diminished the expression of Ki67 and proliferating cell nuclear antigen on KB cells. Incubation of IFNalpha-treated KB cells with 10 nM EGF for 12 h reversed these effects. We then studied several biochemical markers of cell proliferation. Ornithine decarboxylase activity was decreased to about one-tenth by IFNalpha and partly restored by EGF. Hypusine is contained only in eukaryotic initiation factor 5A and its levels are correlated with cell proliferation. IFNalpha decreased hypusine synthesis by 75%; exposure of cells to EGF for 12 h restored hypusine synthesis almost completely. We also studied the effects of IFNalpha on the cytotoxicity of the recombinant toxin TP40, which inhibits elongation factor 2 through EGF-R binding and internalization. IFNalpha greatly enhanced the TP40-induced inhibition of protein synthesis in KB cells. In conclusion, IFNalpha, which affects protein synthesis machinery and increases EGF-R expression, enhances the tumoricidal activity of TP40 and hence could be useful in the setting of anti-cancer therapy.

Effect of Lys-->Arg mutation on the thermal stability of Cu,Zn superoxide dismutase: influence on the monomer-dimer equilibrium

The thermal stability of two single (K3R, K67R) and one double (K3R-K67R) mutants of Xenopus laevis B Cu, Zn superoxide dismutase has been studied to test Lys --> Arg substitution as an 'electrostatically conservative' strategy to increase protein stability. The K3R mutant displays an increased thermostability with respect to the wild-type enzyme, whilst a decreased stability was observed in the case of the K67R and K3R-K67R mutants. Concentration dependence of the apparent inactivation constant (kapp) of the latter mutants, as compared to that of the wild type enzyme and K3R mutant, indicates that their higher sensitivity to heat inactivation is due to a perturbation of the dimer association. These results are confirmed also by fluorescence anisotropy measurements of the internal probe Tyr149. The possible role of Arg67 in perturbing the dimer dissociation equilibrium toward the monomeric form is discussed.

Identification of a substrate site for transglutaminases on the human protein synthesis initiation factor 5A

Protein synthesis initiation factor 5A (eIF-5A) from human erythrocytes was found to be a substrate for both plasma transglutaminase (Factor XIIIa) and guinea pig liver transglutaminase (GPLTG). When purified eIF-5A was incubated with GPLTG or Factor XIIIa in the presence of succinylated beta-casein, a covalent complex was identified. By isolating and analysing the product of the transglutaminases (TGases) reaction, the site of modification on eIF-5A has been identified as the unique amino acid hypusine. The complex beta-casein.eIF-5A was enzymatically digested with proteinases and the predicted covalent cross-link of gamma-glutamyl-omega-hypusine was isolated from the digests by ion-exchange chromatography and purified by reversed-phase h.p.l.c. Acid hydrolysis of the purified dipeptide yielded equimolar amounts of hypusine and glutamic acid. Furthermore, fast atom bombardment m.s. analysis confirmed the isomer assignment to be gamma-glutamyl-omega-hypusine. These data indicate that hypusine-50 of the eIF-5A chain functions as acyl acceptor substrate for TGases, and reveal that eIF-5A may be cross-linked to intracellular proteins by TGases. Because the precise function of eIF-5A is still unknown, our results appear particularly stimulating in the light of the recent finding of a new biological role for this protein as a cellular factor binding specifically to the human immunodeficiency virus-1 Rev activation domain [Ruhl, Himmelspach, Bahr, Hammerschmid, Jaksche, Wolff, Auschauer, Farrington, Probst, Bevec and Hauber (1993) J. Cell Biol. 123, 1309-1320].

[The citizen's opinion on genetic counseling. Acceptability of the service in the province of Ferrara (Cento)]

At Cento (Ferrara), a town characterized by a moderate incidence of thalassemia, only 8.62% of men and 16.53% of women have a fair knowledge of genetic diseases and of their prevention. This lack of information was common to all categories covered by the poll. In spite of this, public was generally in favour of a genetic consultancy service. Table 1 reveals that 74.14% of men and 83.47% of women would use the informations provided by genetic consultancy for preventive purposes.

[The client's viewpoint on genetic counseling. Acceptability of the service in a Bolognese community (Castel San Pietro Terme)]

It has been found that the public's knowledge of genetic diseases and their prevention was extremely limited in the Commune of Castel San Pietro Terme (Bologna). This lack of information was common to all categories covered by the poll. In spite of this, the public was generally in favour of a genetic consultancy service. Overall figures reveal that 84.06% of men and 79.58% of women interviewed would use the information provided by genetic consultancy for preventive purposes.

[The client's viewpoint on genetic counseling. Acceptability of the service in an Oristanese community (Cabras)]

At Cabras (Oristano), a town characterized by a high incidence of thalassaemia and G6PD deficiency less than half the people between 18 and 35 have a fair knowledge of genetic diseases and of their prevention. The lack of information is higher among people working in the primary sector, housewives and generally, among those who are uneducated. The majority of the people we have interviewed are favourable to undergo analysis to single out carriers. Of these many have said to be unwilling to give birth to children if they belong to a couple at risk. Other have said they do not exclude of having children all the same but to be willing to amniocentesys, and to miscarriage if necessary. From a total calculation results that 88,03% of the men and 82,18% of the women we have interviewed would use, as a prevention, the information obtained from a genetic centre.