Factors influencing Helicobacter Pylori positivity in children

Background

Helicobacter pylori (H. pylori) is a common bacteria all over the world. The factors influencing the acquisition and prevalence of H. pylori infection are still poorly understood.

Aims

The aim of this study was to determine the factors that may affect H. pylori positivity in patients who presented to the pediatric clinic.

Subjects and Methods

The study included 374 children who attended the pediatric clinic with gastrointestinal complaints. The demographic characteristics of patients were recorded, and fecal samples were examined for H. pylori positivity with a prepared kit procedure. In addition, the samples were examined under microscope for the diagnosis of parasites in stool. The Chi-square analysis and binary logistic regression analysis were used for data analysis. The odds ratio was calculated as an estimate of the relative risk. Results: The study found the incidence of H. pylori positivity to be 18.7%. It was observed that in all H. pylori positive patients had growth retardation. H. pylori positivity had no significant relationship with the presence of parasites in the stool (p = 0.113). The results of the Chi-square test showed that H. pylori positivity was significantly changed age groups and educational levels. Logistic regression analysis showed that "age" and "educational status" are significant predictors of H. pylori positivity (p = 0.023 and 0.017, respectively). The risk of H. pylori positivity in the 11-18 age group patients was found about two times (OR: 2.024) higher than in the 6-10 age group patients. The risk of H. pylori positivity in those with education level of "Middle school and above" were found to be twice as high (OR: 2.126) than those with a primary education level (OR: 2.126).

Conclusion

In this study, adolescent age and middle school and above level were found to be risk factors for H. pylori. This suggests that there may be other conditions influencing H. pylori positivity. Also, since the frequency of H. pylori is high in those with growth retardation, H. pylori should be considered when evaluating children with growth retardation.

The tolerability of single low dose primaquine in glucose-6-phosphate deficient and normal falciparum-infected Cambodians

Background

The WHO recommends single low-dose primaquine (SLDPQ, 0.25 mg/kg body weight) in falciparum-infected patients to block malaria transmission and contribute to eliminating multidrug resistant Plasmodium falciparum from the Greater Mekong Sub region (GMS). However, the anxiety regarding PQ-induced acute haemolytic anaemia in glucose-6-phosphate dehydrogenase deficiency (G6PDd) has hindered its use. Therefore, we assessed the tolerability of SLDPQ in Cambodia to inform national policy.

Methods

This open randomised trial of dihydroartemisinin-piperaquine (DHAPP) + SLDPQ vs. DHAPP alone recruited Cambodians aged ≥1 year with acute uncomplicated P. falciparum. Randomisation was 4:1 DHAPP+SLDPQ: DHAPP for G6PDd patients and 1:1 for G6PDn patients, according to the results of the qualitative fluorescent spot test. Definitive G6PD status was determined by genotyping. Day (D) 7 haemoglobin (Hb) concentration was the primary outcome measure.

Results

One hundred nine patients (88 males, 21 females), aged 4–76 years (median 23) were enrolled; 12 were G6PDd Viangchan (9 hemizygous males, 3 heterozygous females). Mean nadir Hb occurred on D7 [11.6 (range 6.4 ─ 15.6) g/dL] and was significantly lower (p = 0.040) in G6PDd (n = 9) vs. G6PDn (n = 46) DHAPP+SLDPQ recipients: 10.9 vs. 12.05 g/dL, Δ = -1.15 (95% CI: -2.24 ─ -0.05) g/dL. Three G6PDn patients had D7 Hb concentrations < 8 g/dL; D7-D0 Hbs were 6.4 ─ 6.9, 7.4 ─ 7.4, and 7.5 ─ 8.2 g/dL.

For all patients, mean (range) D7-D0 Hb decline was -1.45 (-4.8 ─ 2.4) g/dL, associated significantly with higher D0 Hb, higher D0 parasitaemia, and receiving DHAPP; G6PDd was not a factor. No patient required a blood transfusion.

Conclusions

DHAPP+SLDPQ was associated with modest Hb declines in G6PD Viangchan, a moderately severe variant. Our data augment growing evidence that SLDPQ in SE Asia is well tolerated and appears safe in G6PDd patients. Cambodia is now deploying SLDPQ and this should encourage other GMS countries to follow suit.

Trial registration

The clinicaltrials.gov reference number is NCT02434952.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3862-1) contains supplementary material, which is available to authorized users.

Focused Screening and Treatment (FSAT): a PCR-based strategy to detect malaria parasite carriers and contain drug resistant P. falciparum, Pailin, Cambodia

Recent studies have shown that Plasmodium falciparum malaria parasites in Pailin province, along the border between Thailand and Cambodia, have become resistant to artemisinin derivatives. To better define the epidemiology of P. falciparum populations and to assess the risk of the possible spread of these parasites outside Pailin, a new epidemiological tool named “Focused Screening and Treatment” (FSAT), based on active molecular detection of asymptomatic parasite carriers was introduced in 2010. Cross-sectional malariometric surveys using PCR were carried out in 20 out of 109 villages in Pailin province. Individuals detected as P. falciparum carriers were treated with atovaquone-proguanil combination plus a single dose of primaquine if the patient was non-G6PD deficient. Interviews were conducted to elicit history of cross-border travel that might contribute to the spread of artemisinin-resistant parasites. After directly observed treatment, patients were followed up and re-examined on day 7 and day 28. Among 6931 individuals screened, prevalence of P. falciparum carriers was less than 1%, of whom 96% were asymptomatic. Only 1.6% of the individuals had a travel history or plans to go outside Cambodia, with none of those tested being positive for P. falciparum. Retrospective analysis, using 2010 routine surveillance data, showed significant differences in the prevalence of asymptomatic carriers discovered by FSAT between villages classified as “high risk” and “low risk” based on malaria incidence data. All positive individuals treated and followed-up until day 28 were cured. No mutant-type allele related to atovaquone resistance was found. FSAT is a potentially useful tool to detect, treat and track clusters of asymptomatic carriers of P. falciparum along with providing valuable epidemiological information regarding cross-border movements of potential malaria parasite carriers and parasite gene flow.

Polypeptides associated with in vitro cyst formation of Blastocystis hominis

The objective of this study was to characterize the polypeptides associated with cysts of Blastocystis hominis. This form is believed to be infective and plays a role in parasite resistance to anti-B. hominis drugs currently used for treatment of Blastocystis associated diarrhea. Cysts were induced through in vitro culture of the parasite in complete medium supplemented with bacterial extract with trypticase, metronidazole or doxycycline. SDS-PAGE analysis showed almost similar polypeptide patterns of parasite extracts obtained from in vitro cultured parasites before and after exposure with the three supplements. Polypeptide bands at 76, 58.5, 48, 45, 40, 38, 32, 25 and 22 kDa were constantly seen in all antigenic preparations and no specific cyst-associated polypeptide was present. However, on immunoblot analysis, 3 out of 16 blastocystosis human sera identified a cyst-associated polypeptide at 60 kDa in all parasite extracts prepared from cultures with the three supplements. In addition, there were associated morphological changes detected in these parasites stained with acridine orange and observed under fluorescence microscopy. Metronidazole induced cyst forms (reddish cells) as early as 12 hours post-exposure; more cyst production (with stronger immunoblot bands) occurred after 24 hours exposure. However, cysts rupture with release and destruction of B. hominis daughters cells occurred after 48 hours exposure. Doxycycline induced less cyst-like forms at 24 hours (weaker 60 kDa band) and less destruction of the cysts (60 kDa band still present at 72 hours post exposure). Bacterial extract and trypticase also induced cysts at 12 hours with increasing numbers up to 72 hours exposure (corresponding increase in intensity of 60 kDa band from samples harvested at 12 to 72 hours post exposure) without any sign of deleterious effect on the parasite.

Energy metabolism in women during short exposure to the thermoneutral zone

Ambient temperature has been shown to affect energy metabolism in field situations. Therefore, we assessed the effect of a short exposure to the thermoneutral zone, i.e., 27 degrees C (81 degrees F), in comparison to the usual ambient temperature of 22 degrees C (72 degrees F), on energy expenditure (EE), substrate oxidation, and energy intake (EI) in a controlled situation. Subjects, i.e., women (ages 22+/-2 years, BMI 22+/-3, 28+/-4% body fat), stayed in a respiration chamber three times for 48 h each: once at 22 degrees C, and twice at 27 degrees C in random order, wearing standardized clothing, executing a standardized daily-activities protocol, and being fed in energy balance (EB). During the last 24 h at 22 degrees C, and once during the last 24 h at 27 degrees C, they were fed ad libitum. At 27 degrees C, compared to at 22 degrees C, EE was 8.9+/-1.3 MJ/day vs. 9.9+/-1.5 MJ/day (P<.001) due to decreases in diet-induced thermogenesis (DIT) and activity-induced energy expenditure (AEE) (P<.01); respiratory quotient (RQ) had increased (P<.05); core (P<.05) and skin (P<.001) temperatures had increased. During ad lib feeding, EI was 90-91% of EE (P=.9), due to changes in energy density (ED) of the food choice (P<.01), and related to changes in body temperature and EE (P<.001). Thus, at 27 degrees C, compared to 22 degrees C, energy metabolism was reduced by reductions in DIT and in AEE, while RQ was increased. Reduction in EI was primarily related to body temperature changes and secondarily to changes in EE.

New and efficient routes to biomolecules substituted with cyclopentadienyltricarbonylrhenium and -technetium derivatives

The small, compact, robust, and nonpolar units of [CpM(CO)3] (M = Re, Tc) coupled with biomolecules may be considered as bioorganometallic entities of potential interest in the field of medicinal chemistry. However, the short half-life of useful radionuclides (186Re t1/2 = 3.7 d, 188Re t1/2 = 16.8 h, 99mTc t1/2 = 6 h), the risks inherent in their use, and their cost have led chemists to search for novel synthetic strategies that allow the rapid introduction of the [CpM(CO)3] moiety as a late step in the course of synthesizing the target molecule. The present paper describes different strategies recently reported in the literature to tackle this problem.

[eta 5-Cyclopentadienyl]metal tricarbonyl pyrylium salts: novel reagents for the specific conjugation of proteins with transition organometallic labels

New specific reagents for the conjugation of organo transition metal species to proteins are described. These reagents are pyrylium salts bearing a (eta 5-C5H4)M(CO)3 (M = Mn and Re) at position 4. They couple with simple amines (n-butylamine and tert-butylamine) and to lysine side chains of proteins (bovine serum albumin and lysozyme) with varying yields. In almost all cases, the final conjugated species is a pyridinium salt, with the exception of lysozyme, for which the reaction ends at the divinylogous amide form. Differences in reactivity for bovine serum albumin and lysozyme can be explained in terms of differences of isoelectric point and steric local environment around the reactive lysine residue.

Labeling of proteins by organometallic complexes of rhenium. (I). Synthesis and biological activity of the conjugates

We describe herein a totally new pathway for the introduction of rhenium in the form of low oxidation state organometallic complexes covalently attached to various proteins. The synthesis of several rhenium conjugates takes advantage of the specificity of N-succinimidyl esters for amino residues. Conjugation experiments were carried out under various conditions, and analysis of the conjugates was performed by FT-IR spectroscopy. Yields were optimized and reached 50%. Furthermore, the conjugate resulting from the coupling of N-succinimidyl 4-[eta 5-cyclopentadienylrhenium tricarbonyl] 4-oxobutanoate to an anti-hTSH monoclonal antibody retained a satisfactory immunoreactivity. Finally, IR detection of conjugates adsorbed onto nitrocellulose membranes was achieved and response was found to be related to the coupling extent of the conjugate.

Syntheses and affinities of novel organometallic-labeled estradiol derivatives: a structure-affinity relationship

Two series of novel estradiol derivatives, including cationic species, labeled with organometallic fragments Cr(CO)3, Cp*Ru+, or Cp*Rh2+ [Cp* = eta 5-C5(CH3)5] either in the 17 alpha-position or on the A-ring were synthesized, and their relative binding affinities (RBA) for the estradiol receptor were determined. The Ru(II) and the Rh(III) cationic derivatives were obtained as stable salts with the following counter anions (BF4-, PF6-, CF3SO3-). The satisfactory RBA values obtained for most complexes belonging to the 17 alpha series confirm that this position tolerates the presence of bulky neutral species. For instance, complex 4, in which the organometallic fragment Cr(CO)3 was attached to the phenyl ring of the 17 alpha-phenylethynyl fragment, exhibited an RBA value of 24%, very similar to that of the uncomplexed estrogen derivative 3. Surprisingly, the analogous cationic species 6 had no affinity for the estradiol receptor. This unprecedented result shows that the hormone binding site of the estrogen receptor does not tolerate the presence of a positive charge in the 17 alpha-position of the steroid. On the other hand, the alpha-face of the A-ring of estradiol did tolerate positively charged organometallic fragments bearing bulky substituents although the RBA value tended to decrease with increasing charge. The counterion in these cationic derivatives also affected binding affinity. For instance, the Ru(II) species 7a containing an CF3SO3- ion exhibited a reasonable RBA value (5.8%) compared to analogous species 13 with a PF6- ion (RBA of only 0.1%). Moreover, the triflate counteranion preserved the phenolic form of the A-ring of the estrogen derivative whereas the PF6- derivative was unstable and rapidly converted into the dienonylic form in buffer. The compared RBAs of the neutral and cationic species illustrate the preferences of the receptor hormone binding site in accepting or rejecting species of hydrophobic or hydrophilic character.

Organometallic estrogens: synthesis, interaction with lamb uterine estrogen receptor, and detection by infrared spectroscopy

As an integral part of the development of a new technique using organometallic markers for the detection of hormone receptors by FT-IR spectroscopy, a series of estradiol derivatives labeled with Cr(CO)3 or Cr(CO)2CS fragments on the A ring has been synthesized. The stereochemistry of one of these steroids, alpha-[3-(dimethyl-tert-butylsiloxy)-17 beta-estradiol]dicarbonyl(thiocarbonyl)chromium(0), has been established by X-ray diffraction. The organochromium-labeled steroids are stable in aqueous methanol solution, and their relative binding affinities to estrogen receptor have been determined; these values vary from 0.4 to 28%. The complex exhibiting the strongest affinity, [3-O-(3-hydroxypropyl)-17 beta-estradiol]-chromium tricarbonyl complex, has been prepared in a tritiated form with a high specific activity (4.1 Ci/mmol). This tritiated hormone binds reversibly to the estradiol receptor in lamb uterine cytosol with an affinity (Kd = 0.85 nM) and number of binding sites (n = 770 fmol/mg of protein) close to the values observed for estradiol itself. The level of nonspecific binding is low, and the hormone is not bound significantly to other nontarget tissues. The observation that the binding affinity of the steroid depends on which side of the steroidal A ring the organometallic label is bound demonstrates the nonequivalence of the two sides of the A ring with respect to the receptor site. The FT-IR spectra of the organochromium markers in the v(CO) region can be used for the detection of the estradiol receptor in lamb uterine cytosol.

Synthesis and receptor binding of polynuclear organometallic estradiol derivatives

Twelve novel organometallic derivatives of estradiol were synthesized with the aim of utilizing organometallic cold bioprobes as radioisotopic labels substitutes for steroid hormone receptor assays. For this purpose, we envisaged the attachment of several stable cobalt, molybdenum, osmium carbonyl clusters (tetra- and pentanuclear species) at estradiol 17 alpha-, 16 alpha-, 2- or 4-positions. The binding affinity of these new complexes for uterine estradiol receptor has been measured by the competitive binding method. The results show that the 17 alpha-position can tolerate substitution by bulky organometallic groups (especially in the case of cobalt and molybdenum carbonyl clusters). Estradiol derivatives which are functionalized at C-4 and C-16 alpha bind estradiol receptor with reasonable affinity and the RBA values are the same for the complexed and uncomplexed hormones. The 2- position is more sensitive to organometallic substitution and the complexation at the 2- alkyne results in a dramatic decrease of the RBA values. These results show that the attachment of polynuclear moieties in estradiol 17 alpha-, 4- and 16 alpha-, positions gives rise to compounds which are of potential utility in a new non-radioisotopic receptor assay since the metal-carbonyl markers are readily detected by high-sensitivity Fourier-transform infra-red spectroscopy.