Polymorphisms of Tumor Necrosis Factor Alpha in Moroccan Patients with Gastric Pathology: New Single-Nucleotide Polymorphisms in TNF-α(-193) (G/A).

Polymorphisms in tumor necrosis factor alpha (TNF-α) gene are emerging as key determinants of gastric diseases. The TNF-α(-308) (G/A) and TNF-α(-238) (G/A) single-nucleotide polymorphisms SNPs are the most extensively studied. However, all these studies are conducted in Caucasian and Asian populations. Thus, for the first time in Africa, we sought to investigate whether polymorphisms in TNF-α gene were associated with the development of gastric pathology in Morocco. Two SNPs located in the promoter region (positions -308 and -238) in TNF-α gene were genotyped in 244 individuals (170 patients and 74 healthy controls). Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression analysis. The TNF-α(-238) (G/A) genotype was significantly associated with a high risk of gastritis and gastric cancer (GC) (P = 0.001 and P = 0.002, resp.). Furthermore, a new polymorphism located in the promoter region at position -193 in TNF-α gene was identified. The distribution of this SNP was markedly different in patients suffering from ulcers. The association between TNF-α(-193) (G/A) genotype and high risk of ulcer was significant (P = 0.03). These results suggest that the TNF-α(-193) (G/A) allele has a protective function against gastric cancer by developing ulcer.

Cannabis, tobacco and domestic fumes intake are associated with nasopharyngeal carcinoma in North Africa.

BACKGROUND: The lifestyle risk factors for nasopharyngeal carcinoma (NPC) in North Africa are not known. METHODS: From 2002 to 2005, we interviewed 636 patients and 615 controls from Algeria, Morocco and Tunisia, frequency-matched by centre, age, sex, and childhood household type (urban/rural). Conditional logistic regression was used to evaluate the association of lifestyles with NPC risk, controlling for socioeconomic status and dietary risk factors. RESULTS: Cigarette smoking and snuff (tobacco powder with additives) intake were significantly associated with differentiated NPC but not with undifferentiated carcinoma (UCNT), which is the major histological type of NPC in these populations. As demonstrated by a stratified permutation test and by conditional logistic regression, marijuana smoking significantly elevated NPC risk independently of cigarette smoking, suggesting dissimilar carcinogenic mechanisms between cannabis and tobacco. Domestic cooking fumes intake by using kanoun (compact charcoal oven) during childhood increased NPC risk, whereas exposure during adulthood had less effect. Neither alcohol nor shisha (water pipe) was associated with risk. CONCLUSION: Tobacco, cannabis and domestic cooking fumes intake are risk factors for NPC in western North Africa.

Purification from human plasma of a hexapeptide that potentiates the sulfation and mitogenic activities of insulin-like growth factors.

The human plasma contains small peptide molecules known as low molecular weight growth factors synergistically increasing certain biological actions of insulin-like growth factors. In the present work we isolated and characterized a hexapeptide with HWESAS as structure. This purified peptide was absolutely necessary for the sulfation activity of insulin-like growth factor-I on chick embryo pelvic cartilages and improved the mitogenic activity of both insulin-like growth factors. The effects of this hexapeptide were confirmed by using the homologous synthetic peptide, that exhibited similar biological effects. Other synthetic peptides with structure derived from hexapeptide were shown to be active: the pentapeptide HWESA appeared more potent than the tripeptide HWE, which is about 170 to 200 times less active than the hexapeptide. The sequence of hexapeptide HWESAS is identified in only one human protein that is C3f, a fragment of C3 complement.

Measurement of intracellular pH in cultured cells by flow cytometry with BCECF-AM.

This study evaluates the suitability of flow cytometry with the fluorochrome BCECF for measuring the intracellular pH (pHi) of cultured cells, and monitors the changes in pHi in murine hybridoma in batch culture and chick embryo fibroblast in monolayer culture (5th passage). The technique produced highly reproducible, repeatable results. The theoretical sensitivity from the calibration curve was 0.0004 pH units. But analysis of the standard deviation of the histogram of the green/red fluorescence ratios indicated a mean sensitivity of 0.08 (0.07-0.09) pH units. Interference due to cell size, fluorochrome incorporation and esterases were minimized by establishing a calibration curve with the cells whose pHi was to be measured using the 525/610 nm fluorescence ratio after excitation at 488 nm. The pHi of exponentially growing, batch cultured hybridomas was 7.50 at the start of culture. pHi increased during the exponential growth phase and dropped towards cell death. The pHi of the chick fibroblasts in monolayer culture was 7.30.

Growth response of adult germ cells to rat androgen-binding protein and human sex hormone-binding globulin.

Androgen-binding protein (ABP) is produced by Sertoli cells depending on the development and the stage of the spermatogenic cycle. Germ cell proliferation is at its peak when ABP is at its peak and secreted towards the testicular basal compartment containing spermatogonia and premeiotic spermatocytes. Rat isolated adult germ cell DNA synthesis was studied in vitro in the presence of ABP with and without steroids and in the presence of pure or recombinant sex steroid hormone-binding globulin (SHBG) using thymidine incorporation. Results are: SHBG is able to promote DNA synthesis in the absence of cofactors. Testosterone reacted negatively to the stimulatory effect of SHBG. We conclude that ABP, the physiological steroid-binding protein, should be considered as a paracrine regulator of spermatogenic DNA synthesis in the adult rat.

Purification from human plasma of a tetrapeptide that potentiates insulin-like growth factor-I activity in chick embryo cartilage.

Human plasma has been shown to contain a low molecular weight factor that potentiates human IGF-I stimulation of glycosaminoglycan synthesis in chick embryo cartilage. The peptide was purified and characterized by Edman degradation and electrospray mass spectrometry. The primary structure determined was: Trp-Gly-His-Glu. A homologous synthetic peptide similarly promoted matrix biosynthesis in cartilage exposed to IGF-I.

Role of the kidney in the production of a low molecular weight growth factor (MW < 1000 Da): experimental study in the pig.

Small peptide molecules known as low molecular weight growth factor (LMW-GF) have been identified in human serum. They enhance the effect of IGF-1 (insulin-like growth factor) on proteoglycan synthesis. In the present work we investigated the role played by the kidney in the production of LMW-GF, using the pig as an experimental model. Six pigs underwent bilateral nephrectomy followed 24 h later by orthotopic autotransplantation of the kidney. Renal and liver functions were evaluated by measurement of serum creatinine, urea, electrolytes, amino transferases (ASAT, ALAT), proteins, and bilirubin. LMW-GF was measured by bioassay using 11-day-old pelvic chick embryo cartilages. We observed that LMW-GF quickly disappeared from pig serum after nephrectomy and only reappeared when transplantation was successful. Reappearance of LMW-GF can precede improvement of renal function evaluated by plasma creatinine levels. These data appear to demonstrate that the kidney is involved in LMW-GF production.

A seric low molecular weight factor modulates IGFs effects on chick cartilage metabolism.

The effects of recombinant human insulin-like growth factors (rhIGF-I and rhIGF-II) alone and in combination with a partially purified serum low molecular weight growth factor (LMW-GF) were studied by measuring proteoglycan (PG) and total protein synthesis by chick embryo cartilage. rhIGF-I alone did not increase the incorporation of L[3H]serine or [35S]Na2SO4 into whole cartilages. LMW-GF + rhIGF-I markedly increased the incorporation of these precursors. rhIGF-I alone stimulated D[3H]glucosamine uptake, and LMW-GF increased the effect of rhIGF-I. These results for whole cartilage were reproduced with glycosaminoglycans (GAG) extracted from cartilage. LMW-GF acted in synergy with rhIGF-I to stimulate PG core protein synthesis, xylosyl transferase activity and sulfation. Total protein synthesis, as measured by [35S]methionine uptake, was not altered by rhIGF-I. LMW-GF plus rhIGF-I increased the incorporation of this precursor into whole cartilage. The effect of rhIGF-II on PG synthesis was different from that of rhIGF-I. rhIGF-II alone stimulated GAG chain lengthening and sulfation. LMW-GF did not modify the effect of rhIGF-II on these steps. In contrast, rhIGF-II did not stimulate the synthesis of core protein. LMW-GF plus rhIGF-II increased the [3H]serine incorporation into the whole cartilage, but this combination did not stimulate the uptake of [3H]serine into extracted GAG. rhIGF-II plus LMW-GF were also without effect on xylosyl transferase activity. The combination of these factors increased the [35S]methionine incorporation into cartilage total proteins. These results suggest that rhIGF-II does not regulate the PG core protein synthesis, but in combination with LMW-GF, stimulates the synthesis of proteins other than proteoglycan core protein.

Role of the kidney in the expression of low molecular weight factors with growth factor activity.

Small molecules of peptidic nature, called low molecular weight growth factors (LMW-GF < 1000 Da) are present in normal human serum ultrafiltrate. They enhance the somatomedin activity as measured by the incorporation of 35SO4 into chick embryo cartilages. On the basis of this in vitro test, LMW-GF activities were measured in serum ultrafiltrates of hemodialyzed patients and renal transplant recipients during the post-transplantation follow-up. LMW-GF activity was always zero in patients with chronic renal failure. It was checked that these results were not due to the presence of low molecular weight somatomedin inhibitors or to the increased sulfate concentration. After successful renal transplantation, the LMW-GF activity of patients ultrafiltrates returned to normal at the same time or before the improvement of renal function. In case of post-transplant complications, a decrease in LMW-GF activity accompanied or even occurred prior to impairment of renal function. In functioning graft, LMW-GF activity reappears rapidly, whereas its normalization is delayed in case of tubular nephropathy or episode of acute rejection. It was suggested that the kidney is involved in LMW-GF molecules production or processing. It could be speculated that LMW-GF activity might be a prognostic factor in renal transplantation.

[Respective roles of high and low molecular weight serum growth factors in the metabolism of proteoglycans and other cartilage macromolecules]. / Rôles respectifs des facteurs de croissance sériques de haut et faible poids moléculaire dans le métabolisme des protéoglycannes et d'autres macromolécules du cartilage.

35S radiolabeling allowed an evaluation to be made of neosynthesized macromolecules in chick embryo cartilage cultures. Activities for growth factors of high (serum retentate) or low (ultrafiltrate below 1,000) molecular weight (MW) were assessed in pelvic cartilage explants and in corresponding incubation media. In the absence of growth factor, 35S was mostly incorporated in glycosaminoglycans (GAGs) as regards the medium and for cartilage, in guanidinium chloride unextractable material. In retentate-enriched medium, 35S incorporation was enhanced in all cartilage GAGs while in the medium, stimulation essentially occurred in macromolecules other than GAGs. Low MW growth factors exclusively enhanced cartilage levels of macromolecules which were insoluble in guanidinium chloride. In the medium, these factors did not display any significant effect. These results indicate that human serum growth factors with high and low MW possess different metabolic targets at the cellular level.