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S Boros

Publications and source records attributed to S Boros.

At least 19 recordsLinked to original sources
PubMed2005

Increasing proportion of late testers among AIDS cases in Italy, 1996-2002.

In recent years, the proportion of individuals who are unaware of being infected with HIV when diagnosed with AIDS (defined as 'late testers') has dramatically increased in several European countries, including Italy. We evaluated the extent and determinants of late testing and its impact in terms of AIDS-defining illnesses among AIDS cases reported to the Italian National AIDS Registry since 1996. Late testers were defined as those persons whose first positive HIV test result was within six months of the AIDS diagnosis. Late testers were more likely to be heterosexual contacts or MSWM, as opposed to IDUs. They were also more likely to come from low prevalence areas of Italy or from foreign countries. At AIDS diagnosis, late testers were less likely to be undergoing HAART or prophylaxis against PCP/toxoplasmosis, compared to non-late testers. The mean CD4 cell count at AIDS diagnosis was significantly lower among late testers. PCP, toxoplasmosis and Kaposi's sarcoma were more frequently diagnosed as an AIDS-defining illness in late testers, who also had a significantly higher risk of presenting with multiple concomitant AIDS-defining illnesses. In conclusion, late testing results in missed opportunities for preventing and treating HIV infection, leading to an increased risk of developing preventable opportunistic infections and death.

AIDS-Related Opportunistic Infections↗
PubMed2005

Infection with human immunodeficiency virus, herpes simplex virus type 2, and human herpes virus 8 in remote villages of southwestern Papua New Guinea.

To investigate the spread of human immunodeficiency virus (HIV) and other sexually transmitted viruses, two serosurveys (the first in 1999 among 56 adults and the second in 2001 among 351 adults) were conducted in remote villages of the southwestern part of Papua New Guinea. Only one individual was positive for antibodies to HIV. In 2001, the seroprevalence of human herpes virus 8 (HHV-8) was 32.2%, and the seroprevalence of herpes simplex virus type 2 (HSV-2) was 27.4%. Both prevalence rates increased with age, and were lower in the villages near the Bensbach River. The seropositivity of HSV-2 was independently correlated with HHV-8 infection. Our data show that the inhabitants of the southwestern region of Papua New Guinea currently experience an extremely low circulation of HIV. However, the high prevalence of infectious agents that can be sexually transmitted, such as HSV-2 and to a lesser extent HHV-8, indicates the presence of behavioral patterns that may facilitate the spread of HIV in this area of currently low endemicity.

HIV↗
PubMed2004

Synthesis of a polysulfated heparin degradation product.

Two suitable methods for the synthesis of the heparin degradation product 2,5-anyhydro-3-O-(alpha-L-idopyranosyluronate)-D-mannitol hexa O-sulfate are reported. The synthesis pathways start from D-glucose and D-glucosamine.

Carbohydrate Sequence↗
PubMed2001

Conversion of 2,6-anhydro-D-altrose and--mannose derivatives with 4-substituted phenyl thiols to prepare compounds with potential antithrombotic activity.

Acetolysis of methyl 3,4-di-O-acetyl-2,6-anhydro-D-altropyranoside afforded a mixture containing, besides 1,3,4-tri-O-acetyl-2,6-anhydro-D-altropyranose, the (1R) and (1S) diastereomers of methyl 2,6-anhydro-D-altrose-tetraacetate. Treatment of this mixture with 4-cyanobenzenethiol in the presence of trimethylsilyl triflate resulted in a mixture containing the 3,4,5-tri-O-acetyl-2,6-anhydro-D-altrose bis(4-cyanophenyl) dithioacetal, the corresponding O-methyl S-aryl monothiohemiacetal diastereomers and the beta-thiopyranoside, respectively. Acetolysis of methyl 3,4-di-O-acetyl-2,6-anhydro-D-mannopyranoside led to a mixture of the (1R) and (1S) diastereomers of methyl 2,6-anhydro-D-mannosetetraacetate, which was converted into the corresponding O-methyl S-aryl monothiohemiacetals. Treatment of 1,1,3,4,5-penta-O-acetyl-2,6-anhydro-aldehydo-D-altrose and -D-mannose with 4-cyano- and 4-nitrobenzenethiol, respectively, in the presence of trimethylsilyl triflate afforded the corresponding dithioacetal derivatives. All arylthio derivatives obtained after deacetylation were tested for their oral antithrombotic activity.

Administration, Oral↗
PubMed2001

Response to highly active antiretroviral therapy according to duration of HIV infection.

OBJECTIVE: To evaluate whether duration of HIV-1 infection influences the response to highly active antiretroviral therapy (HAART). DESIGN: Prospective study of individuals (Italian Seroconversion Study cohort) with well-estimated dates of HIV-1 seroconversion. METHODS: This analysis included 277 participants who began HAART (defined as three antiretroviral drugs used in combination). Cox regression models were used to evaluate the association between duration of infection (as categorical variable [</=3, 3-7.5, >7.5 years from seroconversion] or continuous variable) and an immunologic (rise in CD4 count >100 cells/mm3) and a virologic (decline in plasma HIV-RNA to unquantifiable levels) outcome. All analyses were stratified by center of recruitment and adjustment, when used, was for gender, age at inception of HAART, injection drug use, previous antiretroviral therapy, lag-time between positive and negative HIV test result, year of starting HAART, clinical stage, CD4 count, and HIV-RNA at time of HAART. RESULTS: HAART was initiated a median of 6.4 years after seroconversion. There was a median follow-up of 1.6 years after starting HAART to the calendar cut-off (November 1999). One-hundred-eighty-one (65.3%) patients experienced a decline in viral load to below quantifiable levels and 184 (66.4%) experienced a rise in CD4 >100 cells/mm3. In the Cox models, by 1-year increase in duration of infection, we estimated a lower crude hazard of achieving a CD4 count increase >100 cells (relative hazard [RH], 0.96; 95% confidence interval [CI], 0.92-1.01; p =.09), and a lower hazard of reaching an unquantifiable level of plasma HIV-RNA (RH, 0.97; 95%CI, 0.93-1.02; p =.20). After adjustment, these values became 0.99 (95%CI, 0.93-1.04; p =.62) and 0.98 (95%CI, 0.93-1.04; p =.48), respectively. When duration of HIV infection was considered as a categorical variable, the results were consistent with those already described. CONCLUSIONS: These results suggest that the duration of HIV infection does not seem to play an important independent role in determining the virologic and immunologic responses to HAART.

Adult↗
PubMed2000

Differential impact of combined antiretroviral therapy on the survival of italian patients with specific AIDS-defining illnesses.

BACKGROUND: A decrease in HIV-related mortality and morbidity has been observed since 1996 in most developed countries as a consequence of the extensive use of combined antiretroviral therapies. The purpose of this study was to investigate whether combined antiretroviral therapies had a differential impact on the survival of patients with different AIDS-defining illnesses (ADIs). METHODS: In total, 35,318 persons representing all the adults with AIDS (PWAs) diagnosed in Italy from January 1, 1990 to August 31, 1998 were studied. Actuarial life tables and the Kaplan-Meier method were used to estimate the cumulative probability of survival; the multivariate Cox proportional hazards model was used to estimate adjusted relative hazard of death (RH). RESULTS: Among PWAs diagnosed after 1995, the proportion of survivors 24 months after diagnosis was more than doubled (66%) compared with that of PWAs diagnosed before the end of 1995 (31%). Significantly decreased RHs for some ADIs were observed as early as 1996 (i.e., esophageal candidiasis, Pneumocystis carinii pneumonia, brain toxoplasmosis, HIV-wasting syndrome, and pulmonary tuberculosis). In the last period (1997-1998), the decrease was marked and significant for almost all the ADIs, ranging from 55% to 80% compared with the RHs of the reference year (1995). Conversely, primary lymphoma of the brain and Burkitt's lymphoma showed a low and not statistically significant decrease; these were the ADIs with the worst outcome. CONCLUSIONS: After 1995, there was a rather uniform increase in the survival of PWAs diagnosed with most specific ADIs but not for patients affected by primary brain lymphoma and Burkitt's lymphoma. The determinants of this differential effect need to be investigated.

AIDS-Related Opportunistic Infections↗
PubMed2000

Synthesis of 4-substituted phenyl 3,6-anhydro-1,3-dithio-D-glucofuranosides and -pyranosides as well as 2,6-anhydro-1,2-dithio-alpha-D-altrofuranosides possessing antithrombotic activity.

1,2,5-Tri-O-acetyl-3,6-anhydro-3-thio-D-glucofuranose was synthesised starting from D-glucose and was used as a donor for the glycosidation of 4-cyano- and 4-nitrobenzenethiol. In the latter reaction, besides an anomeric mixture of the 4-nitrophenyl 2,5-di-O-acetyl-3,6-anhydro-1,3-dithio-D-glucofuranosides, the corresponding 2,6-anhydro-1,2-dithio-D-altrofuranosides were also obtained, formed via a rearrangement of the sugar moiety. A similar rearrangement could be observed during the hydrolysis of the glycosidic bond of methyl 3,6-anhydro-2,4-di-O-(4-nitrobenzoyl)-3-thio-alpha-D-glucopyranoside with aqueous trifluoroacetic acid, affording after acetylation besides 1-O-acetyl-3,6-anhydro-2,4-di-O-(4-nitrobenzoyl)-3-thio-alpha-D-glucopyranose (32alpha), 1,1,5-tri-O-acetyl-3,6-anhydro-2,4-di-O-(4-nitrobenzoyl)-3-thio-D-glucose, methyl 3,6-anhydro-2,4-di-O-(4-nitrobenzoyl)-3-thio-beta-D-glucopyranoside and 1,5-di-O-acetyl-2,6-anhydro-3-O-(4-nitrobenzoyl)-2-thio-alpha-D-altrofuranose (40). Glycosidation of 4-cyanobenzethiol with 32alpha in the presence of trimethylsilyl triflate as promoter afforded 4-cyanophenyl 3,6-anhydro-2,4-di-O-(4-nitrobenzoyl)-1,3-dithio-beta-D-glucopyranoside as a minor component only, besides 4-cyanophenyl 3,6-anhydro-2-S-(4-cyanophenyl)-4-O-(4-nitrobenzoyl)-1,2,3-trithio-beta-D-glucopyranoside. When boron trifluoride etherate was used as promoter in the reaction of 32alpha with 4-cyano- and 4-nitrobenzenethiol, the corresponding beta-thioglycosides were obtained, while 40 gave under identical conditions the alpha anomers exclusively. All thioglycosides obtained after deacylation were submitted to biological evaluation. Among these glycosides, the 4-cyanophenyl 3,6-thioanhydro-1,3-dithio-D-glucofuranoside possessed the strongest oral antithrombotic effect.

Animals↗
PubMed2000

Synthesis of 4-cyano- and 4-nitrophenyl 2,5-anhydro- 1,6-dithio-alpha-D-gluco- and -alpha-L-guloseptanosides carrying different substituents at C-3 and C-4.

Treatment of 1,6:2,5-dianhydro-3,4-di-O-methanesulfonyl-1-thio-D-glucitol in methanol with sodium hydroxide afforded 1,6:2,5:3,4-trianhydro-1-thio-allitol, 1,4:2,5-dianhydro-6-methoxy-1-thio-D-galactitol, 1,6:2,5-dianhydro-4-O-methyl-1 -thio-D-glucitol, 1 ,6:2,5-dianhydro-3-O-methanesulfonyl-1 -thio-D-glucitol and 1 ,6:2,5-dianhydro-4-deoxy-1-thio-D-erythro-hex-3-ulose (14) in 5, 4, 28, 5.5 and 41% yield, respectively. Formation of these derivatives can be explained via a common sulfonium intermediate. Reduction of 14 with sodium borohydride and subsequent acetylation afforded 3-O-acetyl-1,6:2,5-dianhydro-4-deoxy-1-thio-D-xylo-hexitol, the absolute configuration of which was proved by X-ray crystallography. The 1,6:2,5-dianhydro-1-thio-D-hexitol derivatives in which the free OH groups were protected by acetylation, methylation or mesylation were converted by a Pummerer reaction of their sulfoxides into the corresponding 1-O-acetyl hexoseptanose derivatives which were used as donors for the glycosidation of 4-cyano- and 4-nitrobenzenethiol, respectively. The Pummerer reaction of 1,6:2,5-dianhydro-4-deoxy-3-O-methyl-1-thio-D-xylo-hexitol S-oxide gave, besides 1-O-acetyl-2,5-anhydro-3-deoxy-4-O-methyl-6-thio-alpha-L- (23) and 1-O-acetyl-2,5-anhydro-4-deoxy-3-O-methyl-6-thio-alpha-D-xylo-hexoseptanose (25), 1-O-acetyl-4-deoxy-2,6-thioanhydro-D-lyxo-hexopyranose, formed in a rearrangement reaction. The same rearrangement took place, when a mixture of 23 and 25 was used as donor in the glycosidation reaction with 4-cyanobenzenethiol, applying trimethylsilyl triflate as promoter. The oral antithrombotic activity of the obtained alpha-thioglycosides was determined in rats, using Pescador's model.

Acetylation↗
PubMed2000

Synthesis of 4-substituted phenyl 2,5-anhydro-1,6-dithio-alpha-D-gluco- and -alpha-L-guloseptanosides possessing antithrombotic activity.

Two independent approaches were investigated for the synthesis of 3,4-di-O-acetyl-1,6:2,5-dianhydro-1-thio-D-glucitol (18), a key intermediate in the synthesis of 1,3,4-tri-O-acetyl-2,5-anhydro-6-thio-alpha-D-glucoseptanose (13), needed as glycosyl donor. In the first approach 1,6-dibromo-1,6-dideoxy-D-mannitol was used as starting material and was converted via 2,5-anhydro-1,6-dibromo-1,6-dideoxy-4-O-methanesulfonyl-3-O-tetrahydropy ranyl-D-glucitol into 18. The second approach started from 1,2:5,6-di-O-isopropylidene-D-mannitol and the allyl, 4-methoxybenzyl as well as the methoxyethoxymethyl groups were used, respectively, for the protection of the 3,4-OH groups. The resulting intermediates were converted via their 1,2:5,6-dianhydro derivatives into the corresponding 3,4-O-protected 2,5-anhydro-6-bromo-6-deoxy-D-glucitol derivatives. The 1,6-thioanhydro bridge was introduced into these compounds by exchanging the bromine with thioacetate, activating OH-1 by mesylation and treating these esters with sodium methoxide. Among these approaches, the 4-methoxybenzyl protection proved to be the most suitable for a large scale preparation of 18. Pummerer rearrangement of the sulfoxide, obtained via oxidation of 18 gave a 1:9 mixture of 1,3,4-tri-O-acetyl-2,5-anhydro-6-thio-alpha-L-gulo- (12) and -D-glucoseptanose 13. When 12 or 13 were used as donors and trimethylsilyl triflate as promoter for the glycosylation of 4-cyanobenzenethiol, a mixture of 4-cyanophenyl 3,4-di-O-acetyl-2,5-anhydro-1,6-dithio-alpha-L-gulo- (58) and -alpha-D-glucoseptanoside (61) was formed suggesting an isomerisation of the heteroallylic system of the intermediate. A similar mixture of 58 and 61 resulted when 18 was treated with N-chloro succinimide and the mixture of chlorides was used in the presence of zinc oxide for the condensation with 4-cyanobenzenethiol. When 4-nitrobenzenethiol was applied as aglycon and boron trifluoride etherate as promoter, a mixture of 4-nitrophenyl 3,4-di-O-acetyl-2,5-anhydro-1,6-dithio-alpha-L-gulo- (60) and -alpha-D-glucoseptanoside (62) was obtained. Deacetylation of 58, 61 and 62 according to Zemplen afforded 4-cyanophenyl 2,5-anhydro-1,6-dithio-alpha-L-glucoseptanoside (59), 4-cyanophenyl 2,5-anhydro-1,6-dithio-alpha-D-glucoseptanoside (63) and 4-nitrophenyl 2,5-anhydro-1,6-dithio-alpha-D-glucoseptanoside (66), respectively. The 4-cyano group of 63 was transformed into the 4-aminothiocarbonyl, and the 4-(methylthio)(imino)methyl derivative and the 4-nitro group of 66 into the acetamido derivative. All of these thioglycosides displayed a stronger oral antithrombotic effect in rats compared with beciparcil, used as reference.

Administration, Oral↗
PubMed2000

Changes in urine 8-hydroxydeoxyguanosine levels of super-marathon runners during a four-day race period.

We have determined the urinary 8-hydroxydeoxyguanosine (8-OHdG) levels of five well trained supra-marathon runners during a four-day race. The daily running distances of the four-day race were the following; 93 km, 120 km, 56 km and 59 km, respectively. Pre-race and post-race urine samples were collected on each day and analyzed by a monoclonal antibody technique. The urinary 8-OHdG content increased significantly on the first day and tended to decrease from the third day. By the fourth day 8-OHdG content was significantly less than measured on the first three days. The serum creatine kinase activity changed in a similar fashion, showing a large increase (P<0.001) up to the third day when it decreased significantly from the peak value (P<0.05). We conclude that extreme physical exercise causes oxidative DNA damage to well trained athletes. However, repeated extreme exercise-induced oxidative stress does not propagate on increase of urinary 8-OHdG, but rather causes an adaptation leading to normalization of oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Differential expressions of protein kinase C isozymes during proliferation and differentiation of human skeletal muscle cells in vitro.

The mechanism of skeletal muscle regeneration in vivo can be well modeled in vitro by culturing skeletal muscle cells. In these cultures mononuclear satellite cells fuse to form polynuclear myotubes by proliferation and differentiation. The aim of this study was to determine how the different protein kinase C (PKC) isozymes were expressed during differentiation of human skeletal muscle in vitro. The expressions of desmin, used as a muscle-specific intermediate filament protein marker of differentiation, and of different PKC isozymes were detected by single and double immunohistochemical labeling, and by Western blot analysis. In skeletal muscle cells we could identify five PKC isozymes (PKC alpha, -gamma, -etha, -theta and -zeta). The expressions of PKC alpha and -zeta did not change significantly during differentiation; their levels of expression were high in the early immature cells and remained unchanged in later phases. In contrast, the expression levels of PKC gamma and -etha increased with differentiation. Furthermore, the cellular localization of PKC gamma markedly altered during differentiation, with a perinuclear-nuclear to cytoplasmic translocation. The change in the level of expression of PKC theta during differentiation showed different pattern; its expression was high during the early phases, but a decreased immunostaining was detected in the matured, well-differentiated myotubes. We conclude, therefore, that cultured human skeletal muscle cells possess a characteristic PKC isozyme pattern, and that the different phases of differentiation are accompanied by different expression patterns of the various isozymes. These data suggest the possible functional and differential roles of PKC isozymes in human skeletal muscle differentiation.

Cell Differentiation↗
PubMed1999

Synthesis of 4-cyanophenyl and 4-nitrophenyl 1,5-dithio-D-ribopyranosides as well as their 2-deoxy and 2,3-dideoxy derivatives possessing antithrombotic activity.

1,2,3,4-Tetra-O-acetyl-5-thio-D-ribopyranose as well as its 1-bromide were used as donors in the reaction with 4-cyano- and 4-nitrobenzenethiol, to give the corresponding thioglycosides in different anomeric ratios depending on the reaction conditions. Zemplén deacetylation afforded 4-cyanophenyl as well as 4-nitrophenyl 1,5-dithio-alpha- and beta-D-ribopyranosides, respectively. 1,3,4-Tri-O-acetyl-2-deoxy-5-thio-D-erythro-pentopyranose was synthesized from methyl 2-deoxy-D-erythro-pentofuranoside and was coupled with 4-cyano- and 4-nitrobenzenethiol to give anomeric mixtures from which 4-cyanophenyl as well as 4-nitrophenyl 1,5-dithio-beta-D-erythro-pentopyranosides were isolated after deacetylation. 1,4-Di-O-acetyl-2,3-dideoxy-5-thio-D-glycero-pentopyranose was obtained starting from 1,2,5,6-di-O-isopropylidene-D-mannitol and used as the donor in the glycosylation reaction with 4-cyano- and 4-nitrobenzenethiol. The resulting anomeric mixtures were separated to give, after deacetylation, 4-cyanophenyl as well as 4-nitrophenyl 2,3-dideoxy-1,5-dithio-beta-D-glycero-pentopyranosides. All of these thioglycosides showed significant antithrombotic activity on rats after oral administration.

Animals↗
PubMed1999

Increasing survival time after AIDS in Italy: the role of new combination antiretroviral therapies. Tuscany AIDS Study Group.

BACKGROUND: In Italy, antiretroviral combination therapy was adopted in mid-1995 and protease inhibitors in mid-1996. OBJECTIVE: To conduct a prospective, population-based, observational study to evaluate the effect of these therapies on the survival of persons with AIDS (PWA). METHODS: PWA living in the Tuscany region diagnosed between 1985 and 31 March 1997 (National AIDS Registry) were studied. Information on antiretroviral drugs, prophylactic treatment, CD4 cell count, and AIDS-defining illnesses was collected for PWA still alive at 1 January 1996 and those diagnosed thereafter (analysis cut-off date, 30 November 1997). Kaplan-Meier curves were calculated by year of diagnosis. A Cox model was then used to estimate the adjusted (by sex, age, HIV exposure category, CD4 cell count, type and number of AIDS-defining illnesses) relative hazard (RH) of death by year of diagnosis and calendar date (considered as a time-dependent variable). Similar analyses were repeated for PWA diagnosed after 1989, having been stratified by disease-specific AIDS condition. A final analysis was performed for PWA still alive at 1 January 1996 or diagnosed thereafter for estimating the effect of single, double and triple combination therapy (time-dependent variables), having adjusted for the above variables and for prophylactic treatment. RESULTS: A total of 1683 (79.5%) out of 2118 PWA died before 1 December 1997. Use of more potent combination therapies, including protease inhibitors, greatly increased during 1997. Median survival was 2.9, 12.3, 13.4, 11.4 and 17.6 months for diagnoses before 1987, in 1987-1990, 1991-1993, 1994 and 1995, respectively; an estimated 62% of those diagnosed in 1996-1997 had survived 15 months after diagnosis. The Cox model showed a trend of decrease of RH for calendar time starting in the first half of 1996, compared with 1994. When stratifying by specific AIDS-defining disease there was no statistically significant evidence that the improved overall survival was due to increased survival only for certain diseases. The final multivariate analysis for the 771 PWA still alive at 1 January 1996 or diagnosed thereafter estimated significant RH < 1.0 for double and triple therapy (RH, 0.61 and 0.36, respectively) compared with no therapy. CONCLUSIONS: A significant reduction in risk of death after AIDS was observed from the second half of 1996, apparently due to the widespread use of antiretroviral combination therapies.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Consecutive epidemics of Q fever in a residential facility for drug abusers: impact on persons with human immunodeficiency virus infection.

Two large outbreaks of Q fever occurred in 1987 and 1988 in an agricultural community for the rehabilitation of drug users. Approximately 40% of the residents were human immunodeficiency virus (HIV)-positive. Two hundred thirty-five residents presented with clinical evidence of a flulike syndrome that was confirmed to be Q fever; moreover, a large proportion of residents developed an asymptomatic infection. Clinical signs and symptoms were rather nonspecific: fever, malaise, and muscle pain that were often associated with pulmonary symptoms. Single or multiple opacities were detected, with mild interstitial inflammation evident on chest roentgenograms. The source of infection was the sheepfold, which is part of the stock-farming activity of the community. Both outbreaks occurred just after lambing had begun. Residents who were exposed during the first epidemic were protected in the second one. The attack rate among HIV-positive residents was significantly higher than that among HIV-negative residents in the first outbreak, whereas only a slight, marginally significant difference was observed in the second outbreak. The clinical features of Q fever did not differ between HIV-positive and HIV-negative individuals. No cases of relapse or chronic disease were observed.

Adult↗
PubMed1998

[Malignant esophageal-respiratory fistula and esophageal stenosis treated with a Gianturco-Z-stent].

Oesophago-respiratory fistula in most instances in a complication of advanced malignant tumours of the oesophagus or the lung. In our patient group eleven oesophago-respiratory and one gastro-respiratory fistulas were encountered. Three patients were operated upon. In one of them with achalasia, early oesophageal carcinoma was discovered in the background of the fistula. Two patients had fistulas without of oesophageal narrowing, therefore, stent implantation into the trachea and bronchus was performed. One of them was previously managed endoscopically with lyodura plug and fibrin glue, but only temporary occlusion of the fistula was obtained. In five patients, seven conventional oesophageal prosthesis (6 Cook, 1 Rüsch) were used to close the fistulas. In one of these patients, three oesophago-respiratory fistulas developed one after the other at the level of the prosthesis funnel. They were closed with three prostheses connected with short silicone tubes. In the last two patients, Gianturco-Z stent was employed. Its advantages over the plastic prostheses include small basic and lager final luminal diameter, lesser predilatation, easier implantation, lower complication and mortality rate. The silicone coated and double funnel stent with expansile force is effective in fistulas closure. On implantation, stent shortening in minimal, allowing precise placement of the stent even in proximal malignant oesophageal stenosis with oesophago-bronchial fistula. The high price of the stent is compensated for by the lower complication rate, shorter hospitalization and subsequent reduction is hospital expenses. Therefore these metal stents should be financed by the National Health Service, at least in specialized centers for managing patients with dysphagia.

Deglutition Disorders↗
PubMed1998

An economic synthesis of 1,2,3,4-tetra-O-acetyl-5-thio-D-xylopyranose and its transformation into 4-substituted-phenyl 1,5-dithio-D- xylopyranosides possessing antithrombotic activity.

D-Xylose was converted via 1,2-O-isopropylidene-alpha-D-xylofuranose (4) into 3-O-benzoyl-5-S-benzoyl-1,2-O-isopropylidene-alpha-D-xylofuranose which, after methanolysis, acetylation and subsequent acetolysis afforded 1,2,3,4-tetra-O-acetyl-5-thio-alpha-D-xylopyranose (14) in an overall yield of 36%. Reaction of 4 with thionyl chloride gave a mixture of the diastereomeric cyclic sulfites, the structures of which were established by X-ray crystallography. Their oxidation with sodium periodate afforded the corresponding cyclic sulfate 23. Treatment of 23 with potassium thioacetate gave the potassium salt of 5-S-acetyl-1,2-O-isopropylidene-alpha-D-xylofuranose 3-O-sulfonic acid (26) which, after methanolysis, acetylation and subsequent acetolysis afforded 14 in an overall yield of 56%. Treatment of 4 with sulfuryl chloride gave a mixture containing 5-chloro-3-O-chlorosulfonyl-5-deoxy-1,2-O-isopropylidene-alpha-D- xylofuranose, 3,7,9,11-tetraoxa-4-thia-10-dimethyl-tricyclo[6,3,0, 0(2,6)]undecane S-dioxide and 23 in a 2:3:7 ratio. Tetraacetate 14 was converted into the alpha-1-bromide 18 as well as into the alpha-1-O-trichloroacetimidate 17. These three compounds were used as donors for the glycosylation with 4-cyanothiophenol, affording the 4-cyanophenyl 2,3,4-tri-O-acetyl-1,5-dithio-alpha- (29) and beta-D-xylopyranoside (30) in different ratios, depending on the reaction conditions. When donor 18 was used in the presence of potassium carbonate, besides 29 and 30 two aryl C-glycosylated-thioglycosides, i.e. 4-cyano-2-(2,3,4-tri-O-acetyl-5-thio-beta-D-xylopyranosyl)phenyl 2,3,4-tri-O-acetyl-1,5-dithio-alpha- and beta-D-xylopyranoside (32 and 33) as well as 4-cyano-2-(2,3,4-tri-O-acetyl-5-thio-beta-D-xylopyranosyl)phenyl disulfide 34 could be isolated as byproducts. Deacetylation of 30 with sodium methoxide in methanol afforded, besides 4-cyano-phenyl 1,5-dithio-beta-D-xylopyranoside (1), the corresponding 4-[(methoxy)(imino)methyl]phenyl glycoside 2. The 4-cyano group of 1 was converted into the 4-aminothiocarbonyl, the 4-(methyl-thio)(imino)methyl, the 4-amidino and the 4-(imino)(hydrazino)methyl group. All of these glycosides showed a significant antithrombotic activity on rats.

Animals↗
PubMed1998

Synthesis of 4-cyanophenyl and 4-nitrophenyl 1,5-dithio-L- and -D-arabinopyranosides possessing antithrombotic activity.

5-S-Benzoyl-2,3-O-isopropylidene-5-thio-L-arabinose, prepared from L-arabinose diethyl dithioacetal gave, on treatment with sodium methoxide in methanol, 4-O-benzoyl-2,3-O-isopropylidene-5-thio-L-arabinopyranose 12 which was converted into its 1-O-acetate 14. Hydrolysis of 12 in acetic acid-water afforded, after acetylation, 1,2,3-tri-O-acetyl-4-O-benzoyl-5-thio-L-arabinopyranose 17 which was transformed into 2,3-di-O-acetyl-4-O-benzoyl-5-thio-L-arabinopyranosyl bromide 20. Zemplén deacylation of 17 gave 5-thio-L-arabinopyranose which was converted via 1,2,3,4-tetra-O-acetyl-5-thio-beta-L-arabinopyranose 5 into 2,3,4-tri-O-acetyl-5-thio-beta-L-arabinopyranosyl bromide 6 and into O-(2,3,4-tri-O-acetyl-5-thio-L-arabinopyranosyl) trichloro-acetimidate 7. Glycosidation of 4-nitrophenol with 12 under the Mitsunobu conditions afforded 4-nitrophenyl 4-O-benzoyl-2,3-O-isopropylidene-5-thio-alpha- and beta-L-arabinopyranoside in a approximately 1:2 ratio. Condensation of the glycosyl donors 6, 7, 17, and 20 with 4-cyano- and 4-nitrobenzenethiol yielded, after deacylation, 4-cyano- and 4-nitrophenyl 1,5-dithio-alpha- and beta-L-arabinopyranosides 28 alpha, 28 beta, 29 alpha and 29 beta in different ratios and yields, depending on the reaction conditions applied. In a similar manner the corresponding D-isomers 30 alpha, 30 beta, 31 alpha and 31 beta were also prepared. All of these glycosides, except 28 alpha, showed a stronger oral antithrombotic effect in rats as compared to beciparcil, used as reference.

Animals↗