Risk factor profiles for gastric cancer prediction with respect to Helicobacter pylori:A study of a tertiary care hospital in Pakistan

BACKGROUND Gastric cancer(GC)is the fourth leading cause of cancer-related deaths worldwide.Diagnosis relies on histopathology and the number of endoscopies is increasing.Helicobacter pylori(H.pylori)infection is a major risk factor.AIM To develop an in-silico GC prediction model to reduce the number of diagnostic surgical procedures.The meta-data of patients with gastroduodenal symptoms,risk factors associated with GC,and H.pylori infection status from Holy Family Hospital Rawalpindi,Pakistan,were used with machine learning.METHODS A cohort of 341 patients was divided into three groups[normal gastric mucosa(NGM),gastroduodenal diseases(GDD),and GC].Information associated with socioeconomic and demographic conditions and GC risk factors was collected using a questionnaire.H.pylori infection status was determined based on urea breath test.The association of these factors and histopathological grades was assessed statistically.K-Nearest Neighbors and Random Forest(RF)machine learning models were tested.RESULTS This study reported an overall frequency of 64.2%(219/341)of H.pylori infection among enrolled subjects.It was higher in GC(74.2%,23/31)as compared to NGM and GDD and higher in males(54.3%,119/219)as compared to females.More abdominal pain(72.4%,247/341)was observed than other clinical symptoms including vomiting,bloating,acid reflux and heartburn.The majority of the GC patients experienced symptoms of vomiting(91%,20/22)with abdominal pain(100%,22/22).The multinomial logistic regression model was statistically significant and correctly classified 80%of the GDD/GC cases.Age,income level,vomiting,bloating and medication had significant association with GDD and GC.A dynamic RF GC-predictive model was developed,which achieved>80%test accuracy.CONCLUSION GC risk factors were incorporated into a computer model to predict the likelihood of developing GC with high sensitivity and specificity.The model is dynamic and will be further improved and validated by including new data in future research studies.Its use may reduce unnecessary endoscopic procedures.It is freely available.

S-Nitroso-N-acetyl-L-cysteine ethyl ester(SNACET) and N-acetyl-L-cysteine ethyl ester(NACET)–Cysteine-based drug candidates with unique pharmacological profiles for oral use as NO, H_2S and GSH suppliers and as antioxidants: Results and overview

S-Nitrosothiols or thionitrites with the general formula RSNO are formally composed of the nitrosyl cation(NOt) and a thiolate(RSà), the base of the corresponding acids RSH. The smallest S-nitrosothiol is HSNO and derives from hydrogen sulfide(HSH, H_2S). The most common physiological S-nitrosothiols are derived from the amino acid L-cysteine(Cys SH). Thus, the simplest S-nitrosothiol is S-nitroso-L-cysteine(Cys SNO). Cys SNO is a spontaneous potent donor of nitric oxide(NO) which activates soluble guanylyl cyclase to form cyclic guanosine monophosphate(c GMP). This activation is associated with multiple biological actions that include relaxation of smooth muscle cells and inhibition of platelet aggregation.Like NO, Cys SNO is a short-lived species and occurs physiologically at concentrations around 1 n M in human blood. Cys SNO can be formed from Cys SH and higher oxides of NO including nitrous acid(HONO)and its anhydride(N_2O_3). The most characteristic feature of RSNO is the S-transnitrosation reaction by which the NOtgroup is reversibly transferred to another thiolate. By this way numerous RSNO can be formed such as the low-molecular-mass S-nitroso-N-acetyl-L-cysteine(SNAC) and S-nitroso-glutathione(GSNO), and the high-molecular-mass S-nitrosol-L-cysteine hemoglobin(Hb Cys SNO) present in erythrocytes and S-nitrosol-L-cysteine albumin(Alb Cys SNO) present in plasma at concentrations of the order of 200 n M. All above mentioned RSNO exert NO-related biological activity, but they must be administered intravenously. This important drawback can be overcome by lipophilic charge-free RSNO.Thus, we prepared the ethyl ester of SNAC, the S-nitroso-N-acetyl-L-cysteine ethyl ester(SNACET), from synthetic N-acetyl-L-cysteine ethyl ester(NACET). Both NACET and SNACET have improved pharmacological features over N-acetyl-L-cysteine(NAC) and S-nitroso-N-acetyl-L-cysteine(SNAC), respectively,including higher oral bioavailability. SNACET exerts NO-related activities which can be utilized in the urogenital tract and in the cardiovascular system. NACET, with high oral bioavailability, is a strong antioxidant and abundant precursor of GSH, unlike its free acid N-acetyl-L-cysteine(NAC). Here, we review the chemical and pharmacological properties of SNACET and NACET as well as their analytical chemistry.We also report new results from the ingestion of S-[^(15) N]nitroso-N-acetyl-L-cysteine ethyl ester(S^(15) NACET) demonstrating the favorable pharmacological profile of SNACET.

S-Adenosyl-L-methionine towards hepatitis C virus expression: Need to consider S-Adenosyl-L-methionine's chemistry, physiology and pharmacokinetics

S-Adenosyl-L-methionine(SAM) is a cofactor serving as a methyl donor in numerous enzymatic reactions. It has been reported that SAM has the potential to modify antioxidant-enzymes, glutathione-biosynthesis and methionine adenosyltransferases-1/2 in hepatitis C virus-expressing cells at millimolar concentrations. The efficacy of SAM at micromolar concentrations and the underlying mechanisms remain to be demonstrated.

GC-NICI-MS analysis of acetazolamide and other sulfonamide (R-SO2-NH2)drugs as pentafluorobenzyl derivatives [R-SO2-N(PFB)2] and quantification of pharmacological acetazolamide in human urine

Acetazolamide(molecular mass(MM),222)belongs to the class of sulfonamides(R-SO2-NH2)and is one of the strongest pharmacological inhibitors of carbonic anhydrase activity.Acetazolamide is excreted unchanged in the urine.Here,we report on the development,validation and biomedical application of a stable-isotope dilution GC-MS method for the reliable quantitative determination of acetazolamide in human urine.The method is based on evaporation to dryness of 50 mL urine aliquots,base-catalyzed derivatization of acetazolamide(d0-AZM)and its internal standard[acetylo-2H3]acetazolamide(d3-AZM)in 30 vol%pentafluorobenzyl(PFB)bromide in acetonitrile(60 min,30C),reconstitution in toluene(200 mL)and injection of 1-mL aliquots.The negative-ion chemical ionization(NICI)mass spectra(methane)of the PFB derivatives contained several intense ions including[M]‒at m/z 581 for d0-AZM and m/z 584 for d3-AZM,suggesting derivatization of their sulfonamide groups to form N,N-dipentafluorobenzyl derivatives(R-SO2-N(PFB)2),i.e.,d0-AZM-(PFB)2 and d3-AZM-(PFB)2,respectively.Quantification was performed by selected-ion monitoring of m/z 581 and 83 for d0-AZM-(PFB)2 and m/z 584 and 86 for d3-AZM-(PFB)2.The limits of detection and quantitation of the method were determined to be 300 fmol(67 pg)and 1 mM of acetazolamide,respectively.Intra-and inter-assay precision and accuracy for acetazolamide in human urine samples in pharmacologically relevant concentration ranges were determined to be 0.3%e4.2%and 95.3%e109%,respectively.The method was applied to measure urinary acetazolamide excretion after ingestion of a 250 mg acetazolamide-containing tablet(Acemit®)by a healthy volunteer.Among other tested sulfonamide drugs,methazolamide(MM,236)was also found to form a N,N-dipentafluorobenzyl derivative,whereas dorzolamide(MM,324)was hardly detectable.No GC-MS peaks were obtained from the PFB bromide derivatization of hydrochlorothiazide(MM,298),xipamide(MM,355),indapamide and metholazone(MM,366 each)or brinzolamide(MM,384).We demonstrate for the first time that sulfonamide drugs can be derivatized with PFB bromide and quantitated by GC-MS.Sulfonamides with MM larger than 236 are likely to be derivatized by PFB bromide but to lack thermal stability.