Evaluation of damage induced by Kwkt and Pikt zymocins against Brettanomyces/Dekkera spoilage yeast, as compared to sulphur dioxide.

AIMS: Over the last few decades, the use of zymocins as biological tools to counteract contamination by spoilage yeast in beverages and food has been widely studied. This study examined the damage induced by the Kwkt and Pikt, two zymocins produced by Kluyeromyces wickerhamii and Wickerhanomyces anomalus, respectively, with antimicrobial activity against Brettanomyces/Dekkera wine-spoilage yeast. METHODS AND RESULTS: The physiological and biochemical characterization of both of these proteins revealed that only Pikt showed a strict relationship between ß-glucosidase activity and killer activity. The minimum inhibitory concentrations and minimum fungicidal concentrations of Kwkt and Pikt showed inhibitory activities against Brettanomyces/Dekkera yeast. Cytofluorimetric evaluation of cell death was based on both cell membrane permeability and cell metabolism, using fluorescence techniques under increasing zymocin levels over different incubation times. The antimicrobial actions of Kwkt and Pikt were also compared with the mode of action of sulphur dioxide. In this last case, the induction of the viable but noncultivable (VBNC) state was confirmed, with the consequent recovery of Brettanomyces yeast after medium replacement. In contrast, Kwkt and Pikt caused irreversible death of these yeast, without recovery of sensitive cells. CONCLUSIONS: Kwkt and Pikt could be proposed as fungistatic or fungicide biocontrol agents in winemaking to control the colonization and development of Brettanomyces/Dekkera yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY: These data support the potential use of zymocins to reduce wine contamination as an alternative to sulphur dioxide that act on sensitive cells. Differently from sulphur dioxide, that could induce a reversible VBNC state, Kwkt and Pikt determine the irreversible damage on sensitive yeasts, ensuring the complete control of spoilage Brettanomyces yeast.

Antimicrobial activity of Metschnikowia pulcherrima on wine yeasts.

AIMS: In the present study, it was investigated the antagonistic behaviour of Metschnikowia pulcherrima, as biocontrol agent, against the main wine yeast species involved in the winemaking process. METHODS AND RESULTS: Seven strains of M. pulcherrima were evaluated for the antimicrobial activity against 114 yeast strains belonging to Pichia, Candida, Hanseniaspora, Kluyveromyces, Saccharomycodes, Torulaspora, Brettanomyces and Saccharomyces genera. Results showed both different inter-generic and intra-generic responses to the antimicrobial action of M. pulcherrima strains. Interestingly, the antimicrobial activity of M. pulcherrima did not have any influence on the growth of Saccharomyces cerevisiae. Instead, M. pulcherrima displayed a broad and effective antimicrobial action on undesired wild spoilage yeasts, such as Brettanomyces/Dekkera, Hanseniaspora and Pichia genera. Fermentation trials carried out in synthetic grape must confirmed the antimicrobial activity of M. pulcherrima, determining the early death of the non-Saccharomyces co-inoculated cultures. CONCLUSIONS: The antimicrobial activity of M. pulcherrima does not seem due to proteinaceous compounds such as killer phenomenon, but to the pulcherriminic acid (the precursor of pulcherrimin pigment) that depletes iron present in the medium, making it not available to the other yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY: These data agree with and further support the potential use of selected M. pulcherrima strains in controlled multistarter fermentations with S. cerevisiae starter cultures.

Transmission of trans effects in dinuclear complexes.

The substitution of a terminal hydride ligand in the complexes [Ir(2)(mu-H)(mu-Pz)(2)H(3)(L)P(i)Pr(3))(2)] (L = NCCH(3) (1) or pyrazole (3)) by chloride provokes a significant change in the lability of the L ligand, despite the fact that the substituted hydride and the L ligand lie in opposite extremes of the diiridium(III) complexes. Detailed structural studies of complex 3 and its chloro-trihydride analogue [Ir(2)(mu-H)(mu-Pz)(2)H(2)Cl(HPz)(P(i)Pr(3))(2)] (4) have shown that this behavior is a consequence of the transmission of ligand trans effects from one extreme of the molecule to the other, with the participation of the bridging hydride. Extended Hückel calculations on model diiridium complexes have suggested that such trans effect transmissions are due to the formation of molecular orbitals of sigma symmetry extended along the backbones of the complexes. This is also an expected feature for metal-metal bonded complexes. The feasibility of the transmission of ligand trans effects and trans influences through metal-metal bonds and its relevance to the understanding of both the reactivity and structures of metal-metal bonded dinuclear compounds have been substantiated through structural studies and selected reactions of the diiridium(II) complexes [Ir(2)(mu-1,8-(NH)(2)naphth)I(CH(3))(CO)(2)(P(i)Pr(3))(2)] (isomers 6 and 7) and their cationic derivatives [Ir(2)(mu-1,8-(NH)(2)naphth)(CH(3))(CO)(2)(P(i)Pr(3))(2)](CF(3)SO(3)) (isomers 8 and 9).

Synthesis of paramagnetic tetranuclear rhodium and iridium complexes with the 2,6-pyridinedithiolate ligand. Redox-induced degradation to diamagnetic triiridium compounds.

The tetranuclear complexes [M4(mu-PyS2)2(diolefin)4] [PyS2 = 2,6-pyridinedithiolate; M = Rh, diolefin = cod (1,5-cyclooctadiene) (1), tfbb (tetrafluorobenzo[5,6]bicyclo[2.2.2]octa-2,5,7-triene) (2); M = Ir, diolefin = cod (3), tfbb (4)] exhibit two one-electron oxidations at a platinum disk electrode in dichloromethane at potentials accessible by chemical reagents. The rhodium tetranuclear complexes were selectively oxidized to the monocationic complexes [Rh4(mu-PyS2)2(diolefin)4](+) (1(+), 2(+)) by mild one-electron oxidants such as [Cp2Fe](+) or [N(C6H4Br-4)3](+) and isolated as the PF6(-), BF4(-), and ClO4(-) salts. Silver salts behave as noninnocent one-electron oxidants for the reactions with the rhodium complexes 1 and 2 since they give sparingly soluble coordination polymers. The complex [Ir4(mu-PyS2)2(cod)4](+) (3(+)) was obtained as the tetrafluoroborate salt by reaction of 3 with 1 molar equiv of AgBF4, but the related complex 4(+) could not be isolated from the chemical oxidation of [Ir4(mu-PyS2)2(tfbb)4] (4) with AgBF4. Oxidation of 3 and 4 with 2 molar equiv of common silver salts resulted in the fragmentation of the complexes to give the diamagnetic triiridium cations [Ir3(mu-PyS2)2(diolefin)3](+). The molecular structure of [Ir3(mu-PyS2)2(cod)3]BF4, determined by X-ray diffraction methods, showed the three metal atoms within an angular arrangement. Both 2,6-pyridinedithiolate tridentate ligands bridge two metal-metal bonded d(7) centers in pseudo octahedral environments and one d(8) square-planar iridium center. An interpretation of the EPR spectra of the 63-electron mixed-valence paramagnetic tetranuclear complexes suggests that the unpaired electron is delocalized over two of the metal atoms in the complexes 1(+)-3(+).

Key factors determining the course of methyl iodide oxidative addition to diamidonaphthalene-bridged diiridium(I) and dirhodium(I) complexes.

The course of methyl iodide oxidative addition to various nucleophilic complexes, [Ir2(mu-1,8-(NH)2naphth)(CO)2(PiPr3)2] (1), [IrRh(mu-1,8-(NH)2naphth)(CO)2(PiPr3)2] (2), and [Rh2(mu-1,8-(NH)2naphth)(CO)2(PR3)2] (R = iPr, 3; Ph, 4; p-tolyl, 5; Me, 6), has been investigated. The CH3I addition to complex 1 readily affords the diiridium(II) complex [Ir2(mu-1,8-(NH)2naphth)I(CH3)(CO)2(PiPr3)2] (7), which undergoes slow rearrangement to give a thermodynamically stable stereoisomer, 8. The reaction of the Ir-Rh complex 2 gives the ionic compound [IrRh(mu-1,8-(NH)2naphth)(CH3)(CO)2(PiPr3)2]I (10). The dirhodium compounds, 3-5, undergo one-center additions to yield acyl complexes of the formula (Rh2(mu-1,8-(NH)2naphth)I(COCH3)(CO)(PR3)2] (R = iPr, 12; Ph, 13; p-tolyl, 14). The structure of 12 has been determined by X-ray diffraction. Further reactions of these Rh(III)-Rh(I) acyl derivatives with CH3I are productive only for the p-tolylphosphine derivative, which affords the bis-acyl complex [Rh2(mu-1,8-(NH)2naphth)(CH3CO)2I2(P(p-tolyl)3)2] (15). The reaction of the PMe3 derivative, 6, allows the isolation of the bis-methyl complex [Rh2(mu-1,8-(NH)2naphth)(mu-I)(CH3)2(CO)2(PMe3)2]I (16a), which emanates from a double one-center addition. Upon reaction with methyl triflate, the starting materials, 1, 2, 3, and 6, give the isostructural cationic methyl complexes 9, 11, 17, and 18, respectively. The behavior of these cationic methyl compounds toward CH3I, CH3OSO2CF3, and tetrabutylamonium iodide is consistent with the role of these species as intermediates in the SN2 addition of CH3I. Compounds 18 and 17 react with an excess of methyl triflate to give [Rh2(mu-1,8-(NH)2naphth)(mu-OSO2CF3)(CH3)2(CO)2(PMe3)2][CF3SO3] (19) and [Rh2(mu-1,8-(NH)2naphth)(OSO2CF3)(COCH3)(CH3)(CO)(PiPr3)2][CF3SO3] (20), respectively. Upon treatment with acetonitrile, complexes 17 and 18 give the isostructural cationic acyl complexes [Rh2(mu-1,8-(NH)2naphth)(COCH3)(NCCH3)(CO)(PR3)2][CF3SO3] (R = iPr, 21; Me, 22). A kinetic study of the reaction leading to 21 shows that formation of these complexes involves a slow insertion step followed by the fast coordination of the acetonitrile. The variety of reactions found in this system can be rationalized in terms of three alternative reaction pathways, which are determined by the effectiveness of the interactions between the two metal centers of the dinuclear complex and by the steric constraints due to the phosphine ligands.

Liver cirrhosis and the risk of primary liver cancer.

The relationship between liver cirrhosis and hepatocellular carcinoma is recognized, but quantification of risk is still uncertain. Therefore, we analysed data from a case-control study conducted in Italy between 1984 and 1997 on 499 cases of incident, histologically confirmed hepatocellular carcinoma and 1,552 controls in hospital with acute, non-neoplastic disease. Overall, 87 (17.4%) cases vs 10 (0.6%) controls reported clinical history of liver cirrhosis. The corresponding odds ratio (OR) was 27.5 (95% confidence interval (CI), 14.3-15.2) after allowance for sociodemographic factors, and 16.2 (95% CI, 7.9-32.9) after simultaneous allowance for all identified confounding factors, including alcohol consumption and clinical history of hepatitis. The association was of similar magnitude for subjects whose cirrhosis was diagnosed < 55 years (OR = 14.8) or at age 55 or over (OR = 20.0), and the multivariate OR was 33.7 < 5 years after diagnosis of cirrhosis, 37.3 between 5 and 9 years, and 7.6 (95% to 2.7-21.3) > or = 10 years since diagnosis of cirrhosis. The association was stronger in males (OR = 23.4) than in females (OR = 5.9), similar in various age groups, and somewhat stronger in more educated subjects (OR = 53.7), with history of hepatitis (OR = 33.1), reporting heavy alcohol consumption (OR = 24.9) or high body mass index (OR = 58.1), although the interaction term was significant only for sex. In terms of population attributable risk, 17% of hepatocellular carcinomas in this population can be attributed to clinical history of liver cirrhosis.

Protein nitrogen appearance in CAPD patients: what is the best formula?

BACKGROUND: The protein equivalent of nitrogen appearance is an indirect index commonly used to assess dietary protein intake in patients on CAPD. Moreover it has been suggested that the ratio between nitrogen appearance and dietary nitrogen intake (fractional urea synthesis) can predict nitrogen balance in uraemic patients. Several formulae to directly calculate the protein equivalent of nitrogen appearance have been published. It has not been established, however, what formulae give the most appropriate estimate of protein intake and nitrogen appearance. STUDY DESIGN: Nitrogen balance studies were carried out in seven stable patients on CAPD. All of the patients were receiving a diet whose protein content (1.2 g/kg/body wt/day) and calorie content (35 kcal/kg/body wt/day) were rigorously controlled. Six formulae for calculating protein equivalent of nitrogen appearance and nitrogen appearance were tested and the agreement of the estimating formulae was evaluated by means of the Bland and Altman method. RESULT: Net nitrogen balance was 1.68 +/- 0.9 g/N day, protein intake (g/day) 81 +/- 19, protein intake (g/kg) 1.05 +/- 0.17. Differences in protein equivalent of nitrogen appearance of up to about 20% were found. The smallest differences between protein equivalent of nitrogen appearance and protein intake were obtained by the formulae of Bergstrom (1 +/- 7 g, limits of agreement -12 and +15 g) and Blumenkrantz (-2 +/- 5 g, limits of agreement -11 and +7 g). The formula of Bergstrom most closely estimated nitrogen appearance (-0.35 +/- 0.89 g). Using such formula, the fractional urea synthesis was 54 +/- 12%, giving evidence of positive nitrogen balances. CONCLUSION: For the routine monitoring of protein equivalent of nitrogen appearance in CAPD patients, we recommend Bergstrom's formula with the determination of dialysate protein losses.

Sexually transmitted diseases and risk of HIV infection.

We have analyzed the association between sexually transmitted diseases (STD) and HIV infection, using data from a cross-sectional survey of subjects attending STD clinics in Northern Italy conducted since 1988. A total of 1,711 subjects (1,259 males, 452 females), who had referred themselves to three STD clinics in Northern Italy for suspected STD or STD treatment, were included for the study. Out of these, 145 subjects (113 males and 32 females) were HIV-positive. A total of 58 HIV-positive and 368 HIV-negative subjects reported a history of STD; the corresponding odds ratio (OR) was 2.3 (95% confidence interval (CI) 1.5-3.6) for subjects reporting a history of STD. Considering various STD in details, the estimated OR was 1.8 (95% CI 0.8-3.8) for a history of gonorrhoea and 1.5 (95% CI 0.8-2.7) of syphilis, and the OR was 1.8 (95% CI 1.0-3.2) and 2.2 (95% CI 1.3-3.8), respectively, for a positive TPHA and VDRL test. The results of the test for HbsAg were available in 50 HIV-positive and 1,028 HIV-negative subjects; the OR of HIV infection in subjects with HbSAg was 3.9 (95% CI 1.7-9.0). Presence of genital ulcers at clinical examination was not significantly associated with the risk of HIV infection (OR yes vs no genital ulcers 1.5, 95% CI 0.6-2.8).

Number of sexual partners, condom use and risk of human immunodeficiency virus infection.

BACKGROUND: To analyse the relation between number of sexual partners, selected sexual habits and the risk of human immunodeficiency virus (HIV) infection. METHODS: We conducted a case-control study nested in a cross-sectional survey conducted among subjects attending sexually transmitted diseases (STD) clinics in Northern Italy. Eligible for the study were 1711 subjects (1259 males, 452 females) who referred themselves for the first time between September 1988 and March 1993 to three STD clinics in Northern Italy for suspected STD or STD treatment. A total of 145 subjects (113 males and 32 females) were HIV positive. RESULTS: In comparison with subjects reporting no or one sexual partner over the 3 years before the interview, the estimated odds ratios (OR) of HIV serum positivity were 1.2 (95% confidence interval [CI]: 0.6-2.3), 0.8 (95% CI: 0.4-1.8) and 0.3 (95% CI: 0.4-2.5) in subjects reporting 2-3, 4-5, and > or = 6 partners, respectively. The results were similar considering separately males and females and in men reporting only homosexual partners. Regular condom use decreased the risk of HIV infection: in comparison with subjects reporting no or occasional use of condoms, the OR of HIV infection was 0.5 (95% CI: 0.4-0.8) for regular users. Considering men only, compared with men with no homosexual intercourse, the OR of HIV infection was 2.3 (95% CI: 1.4-3.9) in those reporting bisexual intercourse and 2.2 (95% CI: 1.2-4.2) in men reporting only homosexual intercourse (among homosexuals). There was no relation between HIV infection risk and receptive anal sex. CONCLUSIONS: The risk of HIV infection does not increase linearly with the number of sexual partners in this population. This is reasonable, as the prevalence of HIV infection in this population is essentially determined by drug use. Caution is needed in the interpretation of these results since the analysis of role of number of sexual partners in male intravenous drug users is impaired by low statistical power.

PIP: It remains to be clearly established how multiple sex partners affect the risk of HIV infection. Northern Italy is a region where the prevalence of HIV infection is high mainly among IV drug users. The authors conducted a case-control study nested in a cross-sectional survey among subjects attending three STD clinics in Bergamo, Brescia, and Verona with the goal of analyzing the relationship between the number of sex partners, selected sex practices, and the risk of HIV infection. The study population was comprised of 1259 males and 452 females who referred themselves for the first time between September 1988 and March 1993 to the clinics for suspected STD or STD treatment. The men were of median age 30 years in the range of 16-70, while the women were of median age 28 years in the range of 16-61. 113 males and 32 females were HIV-seropositive. In comparison with subjects reporting no or one sex partner over the three years before the interview, the estimated odds ratio (OR) of HIV serum positivity were 1.2, 0.8, and 0.3 in subjects reporting 2-3, 4-5, and 6 or more partners, respectively. The risk of HIV infection therefore does not increase linearly with the number of sex partners in this population. These results were similar considering separately males and females and among the 91 men reporting only homosexual partners. 165 men reported themselves as being bisexual. Regular condom use decreased the risk of HIV infection such that the OR of HIV infection was 0.5 for regular users compared to subjects who reported no or occasional use of condoms. Considering men only, compared with men with no homosexual intercourse, the OR of HIV infection was 2.3 among those reporting bisexual intercourse and 2.2 among men reporting only homosexual intercourse. There was no relation between HIV infection risk and receptive anal sex. IV drug use was strongly associated with HIV-seropositivity, while a history of STD was more frequently reported by HIV-positive subjects than by HIV-negative subjects.

Barrier methods of contraception, spermicides, and sexually transmitted diseases: a review.

OBJECTIVE: To understand whether barrier methods of contraception (BMC) and/or spermicides lower the risk of acquiring sexually transmitted disease (STD) and to quantify the protection. DESIGN: Review of published experimental studies, in vitro and in vivo evidence on the issue. SUBJECTS: We reviewed 22 papers that examined the impermeability of BMC in vitro against STD agents or the effect of spermicides, and 60 papers reporting results of epidemiological studies on the risk of STD in users of BMC. RESULTS: There was in vitro evidence that both BMC and spermicides were effective against most sexually transmissible agents. Doubts remain on the effectiveness of BMC and spermicides in normal conditions of use, particularly against human papilloma virus. Natural membrane condoms are not impermeable and pores are seen by electron microscopy. Epidemiological studies show a consistent reduction in the risk for use of condoms against gonococcal (most studies giving relative risk, RR, estimates around 0.4 to 0.6) and HIV infection (RRs between 0.3 and 0.6 in most studies). Spermicides protect women against gonorrhoea and trichomoniasis; their role against other STDs is less clear and there is some indication of an irritative effect on the vaginal mucosa that is likely to be dose-dependent. CONCLUSIONS: A large amount of evidence indicates that BMC reduce the risk of gonorrhoea and HIV transmission, but the results are--at least in quantitative terms--less consistent for other diseases. Implications for individual choices and public health approaches should relate to frequency of exposure and severity of the disease too.

Determinants of sexual habits in Italian females.

OBJECTIVE: To identify characteristics of women reporting multiple sexual partners and early age at first intercourse in Italy. METHOD: Information on 1139 control women (median age 54 years) interviewed as part of a case-control study of cervical neoplasia conducted in the greater Milan area, Northern Italy were analysed using stratified analysis and multiple logistic regression. RESULTS: Overall, 81% of the study sample reported no more than one sexual partner, 10% two and 9% three or more. The proportion reporting multiple sexual partners tended to be higher among younger and more educated women (4% vs 19% of women with respectively less than 7 and 12 or more years of education reported three or more partners). Ever smokers reported a higher number of sexual partners than never smokers. The proportion of nulliparae reporting three or more sexual partners was higher than that of parous women. These findings were confirmed after taking into account in a multivariate analysis the role of potential confounding factors. Furthermore similar findings emerged from an analysis restricted to women aged 40 years or less. Always considering number of sexual partners, no relationship emerged with marital status, spontaneous or induced abortions, lifetime number of reported Pap smears and contraceptive habits. With reference to age at first intercourse, 25% of the study population reported their first intercourse at age 18 or before, 34% between 19 and 22 years, and 41% at age 23 or later. Younger women (that is, more recent cohorts) more frequently reported earlier age at first intercourse and the proportion of never married women reporting early intercourse was higher (51% vs 22% of never married vs married women). No relationship emerged between education, smoking habits, parity, history of spontaneous or induced abortions, number of Pap smears, contraceptive habits, and age at first intercourse. CONCLUSION: This study documents conservative sexual habits in Northern Italian females (at least on the basis of self reporting) but indicates that any educational compaigns towards safe sex should be focused towards younger women, particularly smokers, unmarried and nulliparae.

Segmental lentiginosis with "jentigo" histologic pattern.

We report a case of segmental lentiginosis (unilateral lentiginosis), that is, asymmetric distribution of lentigines on one side of the body, in a 23-year-old woman. Lesions involved the right side of the face and the cervical region, mostly within the area of division of the trigeminal nerve. Histologic examination disclosed a lentiginous pattern as well as some nests of melanocytes at the dermal-epidermal junction (so-called jentigo pattern). Similar cases have been described in the literature under the term "zosteriform lentiginous nevus," which in our opinion makes for confusion since the same term has also been used to describe cases that fit the diagnostic criteria for speckled lentiginous nevus (nevus spilus).

Development of anthralin short-contact therapy in psoriasis: survey of published clinical trials.

In a survey of clinical trials concerning the efficacy of short-contact therapy with anthralin in psoriasis vulgaris, focusing principally on methodologic issues, twenty-four papers published between January 1982 and December 1989, in English, French, and Italian, were selected. Nine of 24 papers reported on more than one trial, giving a total of 37 clinical trials to be evaluated. A great heterogeneity was evident in many aspects of the design and conduct of these trials, making pooling of results impossible. Most trials suffered from flaws in general methodologic aspects such as randomization and blinding. Limitations in general applicability of results were discussed with reference to the popular use of self-control design and selection of composite indexes (e.g., PASI) as an outcome variable. Published trials are not a reliable guide to clinical decisions concerning short-contact therapy, and some methodologic observations we made could be of general interest in designing clinical trials of psoriasis.

Risk factors for HIV infection in adults attending sexually transmitted disease clinics in Italy.

We assessed prevalence and risk factors for human immunodeficiency virus (HIV) infection in 637 patients (506 men, 131 women; median age 30 years, range 17-64) attending between September 1988 and July 1989 for the first time two sexually transmitted disease (STD) clinics in Northern Italy, for suspected or STD treatment. A total of 44 subjects (6.9%, 95% confidence interval, (Cl): 4.9-8.9) were seropositive for HIV antibodies. The prevalence of HIV infection decreased with age, from 9% in patients aged 24 years or less to 3% in those aged 45 years or more (chi 21 trend 4.97, p less than 0.05). Women tended to have a lower prevalence of infection than men (5.3% versus 7.3%) but this was not statistically significant. Compared with men reporting no homosexual intercourse, HIV infection risk was about 50% higher in those reporting bisexual intercourse (age- and sex-adjusted odds ratio (OR) 1.5,95% Cl: 0.6-3.6) and about fourfold in those reporting only homosexual intercourse (OR 3.8, 95% Cl: 1.7-8.5). No clear trend in risk was observed with number of sexual partners both in men and in women. Intravenous drug users had an increased risk of HIV infection; compared with non-users, the OR was 5.6 (95% Cl: 3.0-10.5) in users, and the point estimates increased with frequency of use, from 3.3 (95% Cl: 0.8-11.5) in occasional users to 6.4 (95% Cl: 3.2-12.8) in regular users. The risk of HIV infection was 2.2 (95% Cl: 1.1-4.3) in patients reporting a history of STD, and 1.6 (95% Cl: 0.8-3.3) in those reporting syphilis.(ABSTRACT TRUNCATED AT 250 WORDS)