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A Stepien

Publications and source records attributed to A Stepien.

14 recordsLinked to original sources
PubMed2006

Self-induced vomiting -- risk for oesophageal cancer?

BACKGROUND: Chronic inflammation of the oesophagus is considered a precursor condition for the development of oesophageal cancer. Identification of the causes of chronic oesophageal irritation is therefore relevant in developing preventive measures. Self-induced vomiting is a cultural practice among the black population of South Africa, particularly those living in the Transkei, a region reported to have one of the highest incidences of oesophageal cancer worldwide. METHODS: We retrospectively examined the association between the practice of self-induced vomiting and the development of cytological features of inflammation in 478 self-selected subjects living in Transkei who underwent early screening for oesophageal cancer. Screening involved brush biopsy, cytological investigation and a questionnaire interview. RESULTS: The prevalence of self-induced vomiting was 80.5% and 79.1% in males and females, respectively, and this was stable across all ages. Furthermore, self-induced vomiting was found to be significantly and independently associated with oesophageal chronic inflammation (odds ratio 1.83, 95% confidence interval: 1.13 - 2.96, p = 0.013). CONCLUSION: While the association between the cultural practice of self-induced vomiting and oesophageal cancer has previously been hypothesised, this is the first study to report on an association between this practice and oesophageal chronic inflammation. Further studies that take into account the method used, frequency and duration of vomiting, age of commencement and fasting state of subjects practicing self-induced vomiting coupled with accurate indicators of inflammation are needed to elucidate the role of self-induced vomiting in oesophageal pathogenesis.

Adult↗
PubMed2002

Second messenger systems in the action of LH and oxytocin on porcine endometrial cells in vitro.

LH/hCG as well as oxytocin receptors are present in the porcine endometrium. Oxytocin increases phosphatidylinositol hydrolysis in this tissue, but its action on adenylate cyclase activity is disputed. The second messenger system responding to LH/hCG in endometrial cells has not been established. In this study, we investigated the involvement of protein kinase A and C signaling mechanisms in the action of LH on porcine endometrial cells in vitro. The possibility of cAMP accumulation after treatment of endometrial cells with oxytocin was also investigated. Endometrial tissue was obtained from gilts during Days 12-15 of the estrous cycle. To study the adenylate cyclase system, endometrial cells were cultured for 48 h and then incubated with different doses of LH or oxytocin for 15, 30, 60, and 180 min. To study the phospholipase C system, dispersed cells were first labeled with myo-[3H]inositol and then treated with increasing doses of LH or 100 nM of oxytocin for 30 min. Time- and dose-dependent effect of LH and oxytocin on cAMP concentration was observed. After 30 min of incubation only the highest dose of LH (100 ng/ml) was able to increase cAMP concentration in medium (P < 0.05). Longer periods (1 and 3 h) caused increased cAMP accumulation after treatment with 10 and 100 ng/ml of LH (P < 0.001). Oxytocin-stimulated cAMP concentration was observed after 1 h when only the highest dose (1000 nM) of hormone was used (P < 0.01) and after 3 h of incubation with doses of 10-1000 nM (P < 0.01). LH (10 and 100 ng/ml) increased inositol phosphates (IPs) accumulation in endometrial cells after 30 min of incubation (P < 0.01). Oxytocin involvement in IPs synthesis was more apparent than was LH (P < 0.001 versus P < 0.01). This is the first demonstration that LH receptor signaling leads to increased cAMP generation as well as IPs turnover in porcine endometrium. Oxytocin-dependent cAMP production in endometrial cells of swine was found after longer periods (3 h) of incubation. Our observations lead to the conclusion that both protein kinase A and C second messenger systems are involved in LH action and that oxytocin is able to stimulate adenylate cyclase activity in porcine endometrial cells.

Adenylyl Cyclases↗
PubMed2002

Human papillomavirus associated with oesophageal cancer.

AIM: To study the prevalence and the different types of human papillomavirus (HPV) in patients with oesophageal cancer from a high risk area of South Africa (Transkei). METHODS: DNA samples from 50 paraffin wax embedded tissue sections were analysed by nested polymerase chain reaction (PCR) using the degenerate HPV L1 consensus primer pairs MY09/MY11 and GP5+/GP6+. Positive PCR samples were subjected to DNA sequence analysis. RESULTS: HPV DNA was detected in 23 of the 50 samples. Sequence analysis revealed that most patients (11) harboured DNA to HPV type 11, whereas other types included DNA HPV type 39 (seven patients), type 16 (two patients), and type 52 (one patient). HPV type 39 has not previously been shown to be associated with oesophageal cancer. In contrast to earlier studies that have found HPV type 16 to be more frequently associated with oesophageal cancer, HPV type 11 was the predominant subtype in this study. CONCLUSIONS: The high frequency of occurrence of HPV in oesophageal tumours (23 of 50 patients; 46%) implicates HPV as one of the possible aetiological factors in this disease. The finding that the low risk HPV subtypes predominate indicates that transformation may be effected via the E6 and E7 proteins.

Adult↗
PubMed2001

Nongonadal LH/hCG receptors in pig: functional importance and parallels to human.

Luteinizing hormone (LH) and human chorionic gonadotropin (hCG) share a common receptor in gonadal cells; however, the presence of these receptors has also been detected in several nongonadal but reproduction-associated tissues of pig, human, and other species. There are no data about the ontogeny of the human LH/hCG receptor. The expression of the porcine LH receptor gene in the uterus starts about 10 days after the appearance of this gene in gonads. LH/hCG receptors were found in uterus (myometrium, endometrium), oviduct, cervix, fetal membranes, and umbilical cord in humans and pigs. The main role of LH/hCG receptors in myometrium is stimulation of growth and hyperplasia and relaxation of uterine motility. hCG also increases blood flow in the uterine artery. LH and hCG can increase production of prostaglandins in endometrium, oviduct, and blood vessels. It is suggested that the preovulatory surge of LH plays an important role in controlling oviductal contractions. Human and pig mammary glands also possess LH/hCG receptors through which gonadotropins can affect the metabolism of steroid hormones in this tissue and may play an inhibitory role in mammary carcinogenesis and in the growth of breast tumors.

Aging↗
PubMed2000

Effect of estradiol and progesterone on oviductal LH-receptors and LH-dependent relaxation of the porcine oviduct.

We have previously shown that the porcine oviduct possesses immunoreactive and functional LH receptors and that LH causes relaxation of the oviduct, especially during the periovulatory stage of estrous cycle. The current studies were undertaken to investigate the effects of estradiol and progesterone on LH receptor protein and LH-stimulated motility of the oviduct in steroid-primed ovariectomized gilts. Twenty-one cross-bred gilts were ovariectomized at 6 m.o. of age. Four weeks later gilts received daily intramuscular injection of either 2 mL corn oil (control n = 4), estradiol benzoate (EB) 1.5 mg (n = 6), progesterone 50 mg (n = 5), or 1.5 mg EB plus 50 mg progesterone (n = 6) for 4 consecutive days. The gilts were slaughtered on Day 5 after the first injection of steroids or vehicle. Rings of isthmus and ampulla were collected from each oviduct and placed in a tissue chamber perfused with Kreb's solution for 60 min. The mechanical activity was recorded for 30 min after LH treatment. Immunoreactivity of LHR in the Fallopian tube sections were detected in the epithelium of the tubal mucosa, smooth muscle cells and the blood vessel endothelium. Western blotting showed that porcine oviducts contain 75, 48 and 45 kDa immunoreactive LH receptor proteins, like the corpus luteum (CL). The lowest receptor expression was found in controls and in gilts treated with estradiol or progesterone. Combined treatment with estradiol and progesterone resulted in a significant increase of LH receptor protein concentrations when compared with control animals. In vitro LH treatment affected oviduct contractility of combined estradiol and progesterone treated gilts but not the oviduct of the remaining groups. It also caused a decrease in amplitude, frequency and areas under the curve (AUC) of ampulla (P < 0.05) and the amplitude and AUC of isthmus (P < 0.001) in combined estradiol and progesterone-primed gilts. These results indicate that estradiol and progesterone together, but not separately, increase LH receptor protein in the porcine oviduct and that combined estradiol and progesterone priming is necessary for LH-induced relaxation of the porcine oviduct.

Animals↗
PubMed2000

[Aspergillus spondylodiscitis].

Four weeks after an Amanita phalloides poisoning, a 29-year-old man presented an ocular aspergillosis. One month later he developed a bilateral L5-S1 radicular syndrome. The diagnosis of aspergillar spondylodiscities was established on the basis of x-ray, CT-scan, MRI and pathology findings. Clinical and radiological improvement was obtained with fluconazole.

Adult↗
PubMed2000

LH/hCG receptors in the porcine uterus--a new evidence of their presence in the cervix.

High-affinity LH/hCG binding sites have been characterized in bovine, lepine, murine, human uteri and porcine myometrium and endometrium. In the present studies we analyzed these receptors in the porcine cervix. Radioreceptor ligand assays were performed with cell membrane preparations of the cervix which were analyzed for binding sites specificity, capacity and affinity. Corpus luteum and myometrium were used as positive control tissues. In the cervix there was little competition for receptor occupancy between hCG and porcine FSH (1.2%) or bovineTSH, porcine GH and porcine PRL (0.1%, 0.1% and < 0.001%; respectively) but porcine LH could completely inhibit the binding of [125I] hCG. There was not binding for LH/hCG in crude membrane preparations of kidney or skeletal muscle. The concentration (fmol/mg protein) of cervical LH/hCG receptor did not vary significantly during particular phases of the estrous cycle, except the early luteal phase (Days 6-7) when the level of LH receptors was very low (p < 0.05). The affinity of uterine LH/hCG binding sites in the cervix and the myometrium was not different from the affinity of LH/hCG binding sites in luteal cells. The porcine cervix as well as the myometrium contains a 75- and 48-kDa immunoreactive LH/cCG receptor proteins similar to corpus luteum. Southern blot of RT-PCR products performed to enhance the specificity and sensitivity of LH receptor transcripts determination in uterine tissues revealed that expected fragments of 740 and 470 bp were present in myometrium and corpus luteum. The cervix showed only 740 bp fragment. In situ hydridization showed the expression of mRNA for LH receptor in the epithelium of the cervix. Immunoreactive staining for LH/hCG receptors was also observed only in epithelial cells of the cervical tissue. Our studies are probably the first evidence demonstrating the specific LH/hCG binding sites in female cervix.

Animals↗
PubMed1999

Evidence for the presence of luteinizing hormone-chorionic gonadotrophin receptors in the pig umbilical cord.

Pig umbilical cord, like that of humans, contains two arteries and a vein surrounded by Wharton's jelly with amnion covering the exterior surface. The aim of the present study was to investigate whether LH-hCG receptors are present in the pig umbilical cord, using light microscope immunohistochemistry, semiquantitative autoradiography, western blotting and reverse transcription-polymerase chain reaction. Umbilical cords were collected on days 48, 71 and 103 of fetal life (n = 6). Monoclonal and polyclonal anti-LH receptor antibodies were used to study receptor distribution. Immunoreactivity was observed in the umbilical blood vessels, the epithelium of umbilical amnion and cells in the Wharton's jelly. No differences in LH-hCG receptor distribution related to the sex of the fetus, period of fetal life or section of the umbilical cord were observed. Strong immunostaining was observed in umbilical vein and in umbilical arteries. However, in the arteries, the tunica media expressed weaker receptor immunostaining than did the tunica intima and tunica adventitia. No immunoactivity was detected in non-target tissue (skeletal muscle) but LH receptors were immunostained in the pig ovary. Topical autoradiography showed that vein and arteries in the umbilical cord bind 125I-labelled hCG, which was highly diminished after co-incubation with an excess of unlabelled hCG. The binding of 125I-labelled hCG to the Wharton's jelly and epithelial amnion was less intense than it was to vessels. Gonadotrophin binding sites were not present in the skeletal muscle. The pig umbilical arteries, vein and Wharton's jelly contained a 75 kDa immunoreactive LH-hCG receptor protein similar to that found in corpora lutea. Southern blot analysis of reverse transcription-polymerase chain reaction products, performed to enhance the sensitivity and specificity of LH receptor transcripts determination in umbilical cord tissues, revealed that the expected fragments of 740 and 470 bp were present in the arteries, vein, Wharton's jelly and corpora lutea (positive control). An additional product of 670 bp was found in the corpora lutea and arteries of umbilical cord, but not in the vein and Wharton's jelly. This is probably the first reported evidence of the presence of LH-hCG receptors in the umbilical cord of a non-human female mammal.

Amnion↗
PubMed1998

p53 and p16/CDKN2 gene mutations in esophageal tumors from a high-incidence area in South Africa.

Squamous cell carcinoma of the esophagus has an uneven geographic distribution, with a high incidence in the Transkei region of Eastern Cape Province, South Africa. The precise molecular events associated with tumorigenesis of esophageal cancer in this region have not been characterized. DNA from human esophageal squamous cell carcinomas (n = 76), as well as adjacent tissue samples (n = 9) and blood (n = 50) from the same patients from the Transkei region were screened for somatic mutations. Exons 5-8 of the p53 gene and exons 1-2 of the p16/CDKN2 gene were examined for mutations using PCR-SSCP procedures and DNA sequence analysis. Results show that 17% of the tumors contained small deletions, insertions and point mutations, resulting in frameshifts or amino acid changes in the p53 gene. Among the mutations in the structural p16/CDKN2 gene, 9 were point mutations, 4 were deletions and 3 were insertions. A novel C to T mutation, 25 bp upstream from the ATG start site of p16/CDKN2, which sometimes occurs together with other structural gene variations, was found. The mutations described here are somatic in origin since none of the DNA samples from the adjacent control tissues or blood samples from the same patients had them.

Adult↗
PubMed1998

Level of nitric oxide-dependent cGMP in patients with migraine.

It is believed that nitric oxide (NO) plays a significant role in migraine attacks. This molecule is formed due to the conversion of L-arginine into L-citrulline. The target receptor for NO is ferrum in the heme group of cytoplasmic guanyl cyclase, the enzyme catalyzing cyclic guanosine monophosphate (cGMP) formation. To confirm this hypothesis, cGMP and nitrite level in the blood serum were measured in patients with migraine. The group under study included 37 subjects suffering from migraine with and without aura and 40 normal control subjects. The cGMP was measured during a migraine attack and 60 min following the administration of sumatriptan 6 mg subcutaneously. A statistically significant increase in cGMP level was observed in patients during a migraine attack compared to the controls. This level decreased after the administration of sumatriptan, but it was still higher than in the controls. No correlation was found between the increased cGMP level and pain intensification with clinical symptoms of migraine. The results suggest the participation of biochemical changes in migraine pathogenesis in the L-arginine-NO-cGMP pathway.

Adult↗
PubMedDate not supplied

Synthesis of CpFe(CO)(L) complexes of hydantoin anions (Cp = eta5-C5H5, L = CO, PPh3), and the use of the 5,5-diphenylhydantoin anion complexes as tracers in the nonisotopic immunoassay CMIA of this antiepileptic drug.

As part of our ongoing development of the CMIA nonisotopic immunoassay method, in which the tracers are metal carbonyl complexes and detection is by Fourier transform infrared spectroscopy, we examined the potential use as tracers of the complexes CpFe(CO)2(5,5-diphenylhydantoin) 2d and CpFe(CO)(PPh3)(5, 5-diphenylhydantoin) 3. The present study involved the synthesis of a series of hydantoin complexes (2a-2d), in particular that of the derivative of 5,5-diphenylhydantoin 2d. The structure of 2d was confirmed by X-ray crystallography. The infrared analysis, establishing the position and intensity of the characteristic metal-carbonyl peaks of complexes 2d and 3 in the 1850-2200 cm-1 region, shows that measurement of the absorbance values of these characteristic peaks will permit quantitative analysis in the picomole range, the norm for routine use in immunoassay and thus suitable for use as CMIA tracers. Cross-reaction rates of these tracers with anti-DPH specific antibodies show that 2d and 3 are both recognized by anti-DPH antibodies (cross-reaction rates 43 and 20%, respectively). In developing a CMIA of DPH with these tracers, it was found that 3, with a single, intense band at 1977 cm-1, had very promising IR characteristics for use in multiassay CMIA, but probably owing to its relatively weak affinity for the antibodies, it was not possible to develop a CMIA for DPH using this tracer. Complex 2d, however, showed better recognition by the antibodies, and using this complex as a tracer, it was possible to develop a particularly sensitive monoassay of DPH by the CMIA method.

Anions↗
PubMedDate not supplied

Luteinising hormone receptor kinetic and LH-induced prostaglandin production throughout the oestrous cycle in porcine endometrium.

The present studies were performed to determine the LH/hCG receptor concentration and to evaluate the LH effect on prostaglandin production in porcine endometrium throughout the oestrous cycle. LH/hCG receptors in cell membrane preparations of the endometrium were found from days 12-14 and 15-16 of the oestrous cycle but not in preparations from days 6-7 and 18-20 using the ligand radioreceptor assay. Western blot analysis revealed, however, that the endometrium from all stages of the oestrous cycle contains a 75-kDa immunoreactive LH receptor protein similar to corpora lutea. The incubation of endometrial explants with LH (0, 1, 10 and 100 ng x mL(-1)) resulted in an increase of 13,14-dihydro-15-keto-PGF2alpha accumulation in a dose-dependent manner on days 5, 10, 14 and 16 of the oestrous cycle. The most effective dose was 10 ng LH x mL(-1) on days 5-16, but the strongest effect was found on days 14 and 16 (7.40 +/- 0.14 versus 12.75 +/- 1.40 and 5.67 +/- 0.35 versus 9.4 +/- 1.25 ng x 100 mg(-1) tissue/6 h, respectively; P < 0.01). It was also observed that 10 and 100 ng x mL(-1) of LH significantly increased cyclo-oxygenase expression to 135.2 and 123.5% respectively, above the control value (P < 0.01) on day 16 of the oestrous cycle. Our data suggest that LH receptors are of physiological significance in the porcine endometrium, since LH induces cyclooxygenase synthesis and increases prostaglandin production.

Animals↗
PubMedDate not supplied

Hepatocellular carcinoma in a rural population at risk.

This study of hepatocellular carcinoma in a homogeneous rural Transkeian population at high risk consisted of: evaluation of liver biopsies of 246 patients with hepatocellular carcinoma using routine histology and immunoperoxidase for HBV stains; collection of reliable data on alcohol consumption, blood HBsAg and ALT status in asymptomatic controls from an adequate population sample; assessment of maize intended for human consumption for contamination by carcinogenic fungi. Tumour histology of rural Blacks did not differ from those described in other studies. Cirrhotic livers were present in 45.1% and iron overload in 68% of cases. Tissue HBsAg was detected in 57% (45% of non-cirrhotic and 59% of cirrhotic livers). Asymptomatic controls showed 9.5% of HBsAg positivity, 3.5% had elevated ALT and 41.3% admitted to alcohol abuse. Maize had insignificant contamination by Aspergillus flavus and very frequent contamination by Fusarium moniloforme. This study suggests a multifactorial aetiology of hepatocellular carcinoma, with viral infection being of the most importance.

Adolescent↗