Co-infection of Helicobacter Pylori and intestinal parasites in children of selected Low-income communities in Lagos State, Nigeria

Helicobacter pylori and intestinal parasites cause gastrointestinal diseases with a high prevalence in children in resource limited developing countries. There is paucity of information in Nigeria on co-infection of H. pylori and intestinal parasites. The study was conducted to determine the prevalence of H. pylori and parasite co-infection in children from selected low-income communities in Lagos, Nigeria. Fecal samples were collected from 151 healthy children aged ≤11 years across six low-income communities in Lagos. H. pylori was detected using stool antigen test and conventional PCR assay, intestinal parasites were detected using formol-ether concentration and nested PCR assay. Structured questionnaires were administered to parents and legal guardians of the children by an interviewer to collect relevant data on demographic and lifestyle factors. The prevalence of H. pylori was 31.79% (48), with a higher prevalence in children aged 2-3 years. The prevalence of intestinal parasites was 21.19% (32) with the lowest frequency found in children aged 8-9 years. The parasites detected include: A. lumbricoides (10.6%), G. intestinalis (7.3%), hookworm (1.99%), E. histolytica (0.66%), S. mansoni (0.66%). There was co-infection prevalence of 10.6% (16) which was associated with the parasites: G. intestinalis (7.3%) and A. lumbricoides (3.97%). Polyparasitism with G. intestinalis and A. lumbricoides was reported in 2 children infected with H. pylori. This study which is the first reported in Lagos established a low prevalence of H. pylori and intestinal parasite co-infection in children and provides better understanding of the epidemiology of H. pylori infection associated with intestinal parasites in Nigeria.

C/EBP homologous protein inhibits tissue repair in response to gut injury and is inversely regulated with chronic inflammation

Loss of intestinal epithelial cell (IEC) homeostasis and apoptosis negatively affect intestinal barrier function. Uncontrolled activation of the unfolded protein response (UPR) in IEC contributes to an impaired barrier and is implicated in the pathogenesis of inflammatory bowel diseases. However, the contribution of the UPR target gene C/EBP homologous protein (CHOP), an apoptosis-associated transcription factor, to inflammation-related disease susceptibility remains unclear. Consistent with observations in patients with ulcerative colitis, we show that despite UPR activation in the epithelium, CHOP expression was reduced in mouse models of T-cell-mediated and bacteria-driven colitis. To elucidate the molecular mechanisms of IEC-specific CHOP expression, we generated a conditional transgenic mouse model (Chop(IEC Tg/Tg)). Chop overexpression increased the susceptibility toward dextran sodium sulfate (DSS)-induced intestinal inflammation and mucosal tissue injury. Furthermore, a delayed recovery from DSS-induced colitis and impaired closure of mechanically induced mucosal wounds was observed. Interestingly, these findings seemed to be independent of CHOP-mediated apoptosis. In vitro and in vivo cell cycle analyses rather indicated a role for CHOP in epithelial cell proliferation. In conclusion, these data show that IEC-specific overexpression impairs epithelial cell proliferation and mucosal tissue regeneration, suggesting an important role for CHOP beyond mediating apoptosis.

Prospective study comparing skin impedance with EEG parameters during the induction of anaesthesia with fentanyl and etomidate

Objective

Sympathetic stimulation leads to a change in electrical skin impedance. So far it is unclear whether this effect can be used to measure the effects of anaesthetics during general anaesthesia. The aim of this prospective study is to determine the electrical skin impedance during induction of anaesthesia for coronary artery bypass surgery with fentanyl and etomidate.

Methods

The electrical skin impedance was measured with the help of an electro-sympathicograph (ESG). In 47 patients scheduled for elective cardiac surgery, anaesthesia was induced with intravenous fentanyl 10 μg/kg and etomidate 0.3 mg/kg. During induction, the ESG (Electrosympathicograph), BIS (Bispectral IndeX), BP (arterial blood pressure) and HR (heart rate) values of each patient were recorded every 20 seconds. The observation period from administration of fentanyl to intubation for surgery lasted 4 min.

Results

The ESG recorded significant changes in the electrical skin impedance after administration of fentanyl and etomidate(p < 0.05). During induction of anaesthesia, significant changes of BIS, HR and blood pressure were observed as well (p < 0.05).

Conclusions

The electrical skin impedance measurement may be used to monitor the effects of anesthetics during general anaesthesia.

Animal sexual abuse in a female sheep

A case of animal sexual abuse and sadism in a female sheep is described. The animal suffered severe genital tract injury most likely caused by the insertion and manipulation of a branch of wood and by penile penetration by a human male. Postmortem examination revealed multiple perforations of the vagina with massive haemorrhages. Animal sexual abuse is a complex diagnostic problem in veterinary medicine. Reported cases are often linked to sadism and often lead to the animal's death. Veterinarians should keep in mind animal sexual abuse as a differential diagnosis in cases of anogenital injuries of unknown origin.

Lack of RUNX3 regulation in human gastric cancer

It has been proposed that the transcription factor RUNX3 is the product of a gastric tumour suppressor gene. We examined RUNX3 expression in gastric biopsies from 105 patients with different histological presentations. Surprisingly, immunohistochemical staining detected RUNX3 protein expression only in infiltrating leukocytes but not in the gastric epithelium. Using laser capture microdissection and quantitative reverse transcription-polymerase chain reaction, we confirmed that the level of RUNX3 mRNA expression in the gastric epithelium was very low and was influenced neither by H. pylori infection nor by neoplastic transformation. Instead, RUNX3 was highly expressed in the gastric stroma and the level of expression correlated with the magnitude of H. pylori-induced gastric inflammation. The low level of RUNX3 expression in gastric epithelium and the absence of downregulation in gastric cancer do not support the hypothesis that RUNX3 functions as a gastric tumour suppressor gene.

Cytokine gene polymorphisms influence mucosal cytokine expression, gastric inflammation, and host specific colonisation during Helicobacter pylori infection

BACKGROUND AND AIMS

Recent studies linked cytokine gene polymorphisms to H pylori related gastric cancer development. The current study evaluated the role of cytokine gene polymorphisms for mucosal cytokine expression, the gastric inflammatory response, and bacterial colonisation during H pylori infection.

PATIENTS AND METHODS

In 207 H pylori infected patients with chronic gastritis, polymorphisms at different loci of the interleukin (IL)-10, IL-1B, IL-1 receptor antagonist (IL-1RN), tumour necrosis factor (TNF)-A, and interferon (IFN)-G genes were genotyped by polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) analysis, and allelic discriminating TaqMan PCR. Mucosal cytokine mRNA copy numbers were determined by real time quantitative PCR. Presence of bacterial virulence factors was investigated by cagA, vacAs1/2, and babA2 PCR. Biopsies were assessed with regard to the degrees of granulocytic/lymphocytic infiltration and the presence of intestinal metaplasia (IM) and atrophic gastritis (AG).

RESULTS

Proinflammatory IL-1 polymorphisms (IL-1RN*2(+)/IL-1B-511T/-31C(+)) were associated with increased IL-1beta expression, more severe degrees of inflammation, and an increased prevalence of IM and AG. Carriers of the IL-10-1082G/-819C/-592C alleles (GCC haplotype) had higher mucosal IL-10 mRNA levels than ATA haplotype carriers and were associated with colonisation by more virulent cagA(+), vacAs1(+), and babA2(+) H pylori strains. The TNF-A-307(G/A) and IFN-G+874(A/T) polymorphisms did not influence mucosal cytokine expression or the inflammatory response to H pylori.

CONCLUSIONS

Cytokine gene polymorphisms influence mucosal cytokine expression, gastric inflammation, and the long term development of precancerous lesions in H pylori infection. Host polymorphisms are associated with certain bacterial strain types, suggesting host specific colonisation or adaptation. These findings contribute to the understanding of the complex interplay between host and bacterial factors involved in the development of gastric pathology.

Helicobacter pylori virulence genotypes in Portuguese children and adults with gastroduodenal pathology

The aim of this study was to evaluate the prevalence of virulence genotypes, namely cagA, vacA and babA2, of Helicobacter pylori strains isolated from Portuguese adults and children presenting gastroduodenal pathology. One hundred thirty-six strains were studied, 82 isolated from adult patients (50 with nonulcerative gastritis and 32 with active peptic ulcer) and 58 isolated from children (54 with nonulcerative gastritis and 4 with duodenal ulcer). Genotyping of cagA, vacA and babA2 was assessed by polymerase chain reaction. Overall, Helicobacter pylori strains carrying more virulent genotypes were much more prevalent in adults than in children, particularly the type I ( vacAs1- and cagA-positive) and the triple-positive ( vacAs1-, cagA- and babA2-positive) strains ( P<0.001). A subpopulation of adults and children with nonulcerative gastritis was also studied, and differences in the prevalence of virulent genotypes were observed, either for individual genotypes ( P=0.017 for cagA, P=0.010 for vacAs1) or in combinations, i.e. the type I genotype ( P=0.005) and the triple-positive strains ( P=0.031). There was no difference between the two populations in the distribution of babA2 and m1/m2 genotypes. Considering the cohort effect in the epidemiology of Helicobacter pylori infection, these results suggest that different strains might circulate during different periods of time, or that, after infection in childhood, individual strains will undergo changes during the course of infection.

Gastrin induces expression and promoter activity of the vesicular monoamine transporter subtype 2

Gastric enterochromaffin-like cells produce histamine in response to the antral hormone gastrin and accumulate the biogenic amine in secretory organelles via vesicular monoamine transporter subtype 2. The putative effects of gastrin on vesicular monoamine transporter subtype 2 expression and promoter activity are poorly understood. In the present study we used highly enriched rat enterochromaffin-like cells (purity, >90%) and rat pheochromocytoma cells stably transfected with a gastrin/cholecystokinin B receptor to investigate the expression and transcriptional regulation of vesicular monoamine transporter subtype 2. Stimulation of vesicular monoamine transporter subtype 2 mRNA and protein expression was observed in isolated enterochromaffin-like cells after 3- to 7-h incubation with gastrin (10(-7) M), forskolin (10(-5) M), or ionomycin (10(-5) M). Deletion analysis of the rat vesicular monoamine transporter subtype 2 promoter defined the minimal promoter sequence necessary for full basal activity as a -121 bp segment upstream of exon 1 containing two Sp1 sites (-97 to -88 bp and -68 to -59 bp) and a cAMP-responsive element (-44 to -35 bp). Gastrin (10(-7) M) stimulated extracellular signal related kinase1/2 phosphorylation, activated Sp1 and cAMP-responsive element-binding protein, and further induced activity of the complete rat vesicular monoamine transporter subtype 2 promoter (-800 bp) in gastrin/cholecystokinin B receptor cells. The -121-bp fragment was able to confer full gastrin responsiveness, and site-directed mutagenesis of the Sp1 and cAMP-responsive element motifs demonstrated their crucial importance for basal and inducible activities. Comparison of promoter activity of histidine decarboxylase, chromogranin A, or vesicular monoamine transporter subtype 2 in transfected cell lines revealed significant differences in basal and gastrin-stimulated activities. Our current study provides the first evidence that gastrin directly stimulates the expression and promoter activity of vesicular monoamine transporter subtype 2. Sp1 and cAMP-responsive element-binding protein recognition motifs located within 121 bp upstream of exon 1 appear to be indispensable for full basal and inducible promoter activities. Diverging effects of gastrin on histidine decarboxylase, chromogranin A, and vesicular monoamine transporter subtype 2 promoter may account for the coordinated synthesis and storage of histamine in this neuroendocrine cell type.

Key importance of the Helicobacter pylori adherence factor blood group antigen binding adhesin during chronic gastric inflammation

Helicobacter pylori has been assigned as a class I carcinogen because of its relation to gastric adenocarcinoma. Chronic H. pylori infection may lead to severe gastritis, glandular atrophy (AT), and intestinal metaplasia (IM). Strains secreting the vacuolating toxin VacA and producing the cytotoxin-associated antigen CagA (type 1 strains), as well as the blood group antigen binding adhesin (BabA) targeting Lewis(b) antigens, have been associated previously with distal gastric adenocarcinoma (M. Gerhard et al., Proc. Natl. Acad. Sci. USA, 96: 12778-12783, 1999) and may therefore also be related to lesions preceding gastric cancer. Antral and corpus biopsies were collected from 451 patients; 151 were H. pylori positive, as determined by PCR. Gastric biopsies were histologically evaluated for activity of gastritis (G0-G3, granulocyte infiltration), chronicity of gastritis (L1-L3, lymphocyte infiltration), and the presence of IM and/or AT according to the Sydney classification. Simultaneously, the presence of bacterial genes encoding virulence and adherence factors (racAs1/s2, cagA, and babA2) was determined by PCR. The presence of cagA+ and vacAs1 (alone or combined) both correlated with activity and chronicity of gastritis (P < 0.05); however, the overall prevalence of these genes was 60 or 72%, respectively, and was thus relatively frequent. The babA2 gene, encoding the adhesin BabA, was detected in 38% of infected patients and was correlated with the activity of gastritis in antrum and corpus (P < 0.005). cagA+/vacAs1+ strains (suggesting the presence of type 1 strains) that were also babA2 positive were detected more frequently in patients with severe histological alterations (such as G3, IM, or AT) compared with subjects without these changes (P < 0.01). cagA+/vacAs1+ strains that were babA2 negative, however, lacked a significant correlation with severe histological changes, activity, or chronicity of gastritis in antrum and corpus. Adherence of H. pylori via BabA appears to be of importance for efficient delivery of VacA and CagA and may play a special role in the pathogenesis of severe histological changes.

Rac1 in human breast cancer: overexpression, mutation analysis, and characterization of a new isoform, Rac1b

Rac1 is a member of the Ras superfamily of small guanosine triphosphatases (GTPases) that act as molecular switches to control cytoskeletal rearrangements and cell growth. Analogous to Ras, constitutively activating point mutations of Rac1 cause tumorigenic transformation of cell lines. However, there is no information about whether Rac1 is also mutated in vivo. After RT - PCR of Rac1, several clones of seven benign and 10 malignant breast cancer tissues as well as eight breast cancer cell lines were sequenced. Only single-nucleotide polymorphisms of Rac1 could be detected, and none of these corresponded to constitutively activating point mutations that have been used in cell lines for transformation. While sequencing Rac1 in breast tissues, a new Rac1 isoform with an insertion of 19 codons within the reading frame of Rac1 close to switch region II was identified and named Rac1b. The Rac1b protein acts like a fast cycling GTPase in GTP binding and hydrolysis assays. In Northern and Western blot experiments both Rac1 RNA and Rac1 protein had a significantly higher expression in breast cancer tissues compared to normal breast tissue samples. Immunohistochemical staining of Rac1 showed weak Rac1 expression in benign breast disease but high expression level in ductal carcinoma-in-situ, primary breast cancer, and lymph node metastases. In addition, breast tumor cells from patients with recurrent disease had Rac1 expression at the plasma membrane, suggesting activation of Rac1, in patients with aggressive breast cancer. Oncogene (2000).

IL-1beta-induced apoptosis in rat gastric enterochromaffin-like cells is mediated by iNOS, NF-kappaB, and Bax protein

BACKGROUND & AIMS

Enterochromaffin-like (ECL) cells are histamine-containing endocrine cells in the gastric mucosa. Previous studies have shown that the proinflammatory cytokine interleukin (IL)-1beta present during chronic gastritis inhibits histamine synthesis in ECL cells and leads to sustained functional impairment. This study investigated the effects of IL-1beta on ECL cell apoptosis and the related signal-transduction mechanisms.

METHODS

ECL cells were isolated by pronase digestion and a combination of elutriation, gradient centrifugation, and 48-hour culture (purity >/=90%). Apoptosis was measured by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling reaction and cell death detection enzyme-linked immunosorbent assay.

RESULTS

IL-1beta (100 pg/mL) increased the rate of programmed cell death 2-3 fold in ECL cells after 24 hours of incubation (total of 12%-14%). This effect was completely inhibited by the NF-kappaB inhibitor, proteasome inhibitor I, and the nitric oxide synthase inhibitor (iNOS) N(G)-monomethyl-L-arginine (10(-4) mol/L), but not by the caspase 3 inhibitor, Asp-Glu-Val-Asp-CHO. Western blot analysis, reverse-transcription polymerase chain reaction (PCR), and in situ PCR showed that IL-1beta induced gene expression (after 2-4 hours) and protein synthesis (6-18 hours) of the iNOS isoform in ECL cells. Bax protein expression was increased in response to IL-1beta. In contrast, bcl-2 gene expression was increased in response to basic fibroblast growth factor, which has been shown to counteract IL-1beta- induced apoptosis.

CONCLUSIONS

These data suggest that IL-1beta induces programmed cell death in isolated rat ECL cells via activation of NF-kappaB, iNOS, and the Bax protein.

The mechanism of histamine secretion from gastric enterochromaffin-like cells

Enterochromaffin-like (ECL) cells play a pivotal role in the peripheral regulation of gastric acid secretion as they respond to the functionally important gastrointestinal hormones gastrin and somatostatin and neural mediators such as pituitary adenylate cyclase-activating peptide and galanin. Gastrin is the key stimulus of histamine release from ECL cells in vivo and in vitro. Voltage-gated K(+) and Ca(2+) channels have been detected on isolated ECL cells. Exocytosis of histamine following gastrin stimulation and Ca(2+) entry across the plasma membrane is catalyzed by synaptobrevin and synaptosomal-associated protein of 25 kDa, both characterized as a soluble N-ethylmaleimide-sensitive factor attachment protein receptor protein. Histamine release occurs from different cellular pools: preexisting vacuolar histamine immediately released by Ca(2+) entry or newly synthesized histamine following induction of histidine decarboxylase (HDC) by gastrin stimulation. Histamine is synthesized by cytoplasmic HDC and accumulated in secretory vesicles by proton-histamine countertransport via the vesicular monoamine transporter subtype 2 (VMAT-2). The promoter region of HDC contains Ca(2+)-, cAMP-, and protein kinase C-responsive elements. The gene promoter for VMAT-2, however, lacks TATA boxes but contains regulatory elements for the hormones glucagon and somatostatin. Histamine secretion from ECL cells is thereby under a complex regulation of hormonal signals and can be targeted at several steps during the process of exocytosis.

Clinical relevance of the Helicobacter pylori gene for blood-group antigen-binding adhesin

Infection with Helicobacter pylori is associated with different human gastric diseases. Biochemical studies, in vitro adherence assays, and in vivo animal models revealed that epithelial attachment of H. pylori can be mediated by the blood-group antigen-binding adhesin (BabA) targeting human Lewis(b) surface epitopes. Studies with transgenic mice expressing the Lewis(b) epitope have shown that such attachment can alter disease outcome. In the current study, the presence of the babA2 gene encoding the adhesin was investigated in clinical isolates from a German population by using PCR and reverse transcription-PCR. A positive genotype was correlated to allelic variations in the genes encoding VacA and CagA and also to the prevalence of duodenal ulcer, distal gastric adenocarcinoma, mucosa-associated lymphoid tissue lymphoma, and antral gastritis. The presence of babA2 was significantly associated with duodenal ulcer (P = 0.0002) and adenocarcinoma (P = 0.033). In contrast, type 1 strains (vacAs1- and cagA-positive) were associated with only duodenal ulcer (P = 0.004) but not adenocarcinoma (P = 0.235). Genotype presence of babA2, vacAs1, and cagA ("triple-positive" strains) showed a highly significant correlation to the prevalence of ulcer (P = 0.000002) and adenocarcinoma (P = 0.014) and discriminated significantly better between disease outcome than did the current type 1 classification. These results indicate that the babA2 gene is of high clinical relevance and would be a useful marker to identify patients who are at higher risk for specific H. pylori-related diseases.

Plasma alpha-tocopherol and coronary endothelium-dependent vasodilator function

BACKGROUND

In the presence of atherosclerosis, the coronary endothelial vasomotor response to acetylcholine is frequently abnormal but is variable between patients. We tested the hypothesis that the plasma concentration of alpha-tocopherol is associated with the preservation of nitric oxide-mediated endothelium-dependent vasomotion.

METHODS AND RESULTS

We studied 15 men and 6 women (mean age 61+/-10 years) at coronary angiography who were not taking vitamin supplements. Coronary endothelium-dependent and -independent vasomotion was assessed by intracoronary infusions of acetylcholine and nitroglycerin. The vasomotor responses were compared with the plasma concentration of alpha-tocopherol and the plasma alpha-tocopherol concentration relative to total lipid (total cholesterol plus triglycerides). The mean plasma alpha-tocopherol was 25.6+/-6.1 micromol/L, total cholesterol 193+/-27 mg/dL, triglycerides 115+/-66 mg/dL, and alpha-tocopherol to total lipid 4. 2+/-0.9 micromol. L(-1). (mmol/L)(-1). The mean vasomotor response to acetylcholine was -1% (range -33% to 28%) and to nitroglycerin 22% (range 0% to 54%). Plasma alpha-tocopherol was significantly correlated with the acetylcholine response (r=0.49, P<0.05) but not the nitroglycerin response (r=0.13, P>0.05). The acetylcholine response remained significant after adjustment for other potential sources of oxidant stress (total cholesterol, diabetes mellitus, smoking, angina class) (P<0.01). The relative concentration of alpha-tocopherol to total lipid was not related to endothelial function (r=0.24, P=0.3, n=20).

CONCLUSIONS

alpha-Tocopherol may preserve endothelial vasomotor function in patients with coronary atherosclerosis. This effect may be related primarily to the action of alpha-tocopherol in the vascular wall. Further studies that assess the impact of alpha-tocopherol supplementation as therapy of endothelial dysfunction are justified.

Estradiol therapy combined with progesterone and endothelium-dependent vasodilation in postmenopausal women

BACKGROUND

Epidemiological studies indicate that estrogen replacement therapy decreases the risk of cardiovascular events in postmenopausal women. Estrogen may confer cardiovascular protection by improving endothelial function because it increases endothelium-dependent vasodilation. It is not known whether progesterone attenuates the beneficial effects of estrogen on endothelial function.

METHODS AND RESULTS

Seventeen postmenopausal women with mild hypercholesterolemia were enrolled in a placebo-controlled, crossover trial to evaluate the effect of transdermal estradiol, with and without vaginal micronized progesterone, on endothelium-dependent vasodilation in a peripheral conduit artery. Brachial artery diameter was measured with high-resolution B-mode ultrasonography. To assess endothelium-dependent vasodilation, brachial artery diameter was determined at baseline and after a flow stimulus induced by reactive hyperemia. To assess endothelium-independent vasodilation, brachial artery diameter was measured after administration of sublingual nitroglycerin. During estradiol therapy, reactive hyperemia caused an 11.1+/-1.0% change in brachial artery diameter compared with 4. 7+/-0.6% during placebo therapy (P<0.001). Progesterone did not significantly attenuate this improvement. During combined estrogen and progesterone therapy, flow-mediated vasodilation of the brachial artery was 9.6+/-0.8% (P=NS versus estradiol alone). Endothelium-independent vasodilation was not altered by estradiol therapy, either with or without progesterone, compared with placebo. There was a modest decrease in total and LDL cholesterol during treatment both with estradiol alone and when estradiol was combined with progesterone (all P<0.001 versus placebo). In a multivariate analysis that included serum estradiol, progesterone, total and LDL cholesterol concentrations, blood pressure, and heart rate, only the estradiol level was a significant predictor of endothelium-dependent vasodilation.

CONCLUSIONS

The addition of micronized progesterone does not attenuate the favorable effect of estradiol on endothelium-dependent vasodilation. The vasoprotective effect of hormone replacement therapy may extend beyond its beneficial actions on lipids.

Hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans

BACKGROUND

Hyperhomocyst(e)inemia is a risk factor for atherosclerosis and is prevalent in the elderly. The objective of this study was to determine whether hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans.

METHODS AND RESULTS

High-resolution vascular ultrasonography was used to study endothelium-dependent and -independent vasodilation in a nonatherosclerotic peripheral conduit artery of 26 elderly hyperhomocyst(e)inemic subjects and 15 age- and sex-matched subjects with normal homocysteine levels. Flow-mediated, endothelium-dependent (nitric oxide-mediated) vasodilation was assessed by measuring the percent change in brachial artery diameter during reactive hyperemia. Endothelium-independent vasodilation was assessed after the administration of 0.4 mg sublingual nitroglycerin. Endothelium-dependent vasodilation was significantly impaired in the hyperhomocyst(e)inemic subjects compared with control subjects (3.7 +/- 0.6% versus 8.1 +/- 1.2%; P = .004), whereas endothelium-independent vasodilation was not different between the two groups (10.1 +/- 1.6% versus 9.3 +/- 1.5%; P = NS). In a linear regression analysis with serum homocysteine concentration, folic acid, age, sex, cholesterol (serum total, LDL, or HDL cholesterol), mean arterial blood pressure, use of antihypertensive medication, and baseline brachial artery diameter included as covariates, serum homocysteine concentration emerged as the only significant predictor of flow-mediated vasodilation.

CONCLUSIONS

These data indicate that hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans and suggest that the bioavailability of nitric oxide is decreased in hyperhomocyst(e)inemic humans.

Quality management and influential factors for the detection of single metastatic cancer cells by reverse transcriptase polymerase chain reaction

The sensitive and specific detection of micrometastasis holds great promise for earlier staging of cancer patients. By amplification of tissue-specific gene expression, the reverse transcriptase polymerase chain reaction (rtPCR) readily detects single tumour cells in different tissues. An increasing number of rtPCR assays with possible relevance for routine laboratory diagnostic procedures is currently being reported in the literature. Interestingly, when used in the clinical setting, assays for the same target mRNA perform very differently, despite comparable sensitivities and specificities in-vitro. Using rtPCRs specific for carcinoembryonic antigen (CEA), prostate-specific antigen (PSA) and cytokeratin 18 (CK 18), we have started to systematically investigate, both experimentally and in clinical specimens, a number of factors that contribute to the varying and seemingly implausible test results. Here we have concentrated on sample collection modalities, assay stability and test reproducibility at the sensitivity limit. Our results demonstrate in detail that, at the maximum sensitivity required for micrometastasis detection, preanalytical and statistical influences increasingly become important for the consistency of the assay results. We conclude that the prerequisite for translating the results from highly sensitive and specific rtPCR assays into clinically relevant data is the thorough definition of assay procedures and the number of tests performed on a sample. Addressing questions of standardization and quality control management is a central aspect yet to be emphasized in assay development and application of routine laboratory rtPCR tests in oncology.

Aging progressively impairs endothelium-dependent vasodilation in forearm resistance vessels of humans

Studies in experimental models suggest that endothelium-derived nitric oxide is reduced with aging, and this circumstance may be relevant to atherogenesis. The aim of this study was to determine whether increasing age resulted in altered endothelium-dependent vasodilation in the forearm resistance vessels of healthy humans. Forearm blood flow was measured in 119 healthy subjects, aged 19 to 69 years, by venous occlusion plethysmography. Brachial artery infusions of methacholine chloride (0.03 to 10.0 microgram/min) were used to assess endothelium-dependent vasodilation and of sodium nitroprusside (0.03 to 10.0 microgram/min) to assess endothelium-independent vasodilation. The slope of the dose-blood flow response relation was calculated in each subject for each drug. Univariate and multiple stepwise regression analyses were used to relate vascular reactivity to selected variables, including age, lipids, and blood pressure. Endothelium-dependent vasodilation was progressively impaired with increasing age, assessed as a reduction in slope from 2.25 +/- 0.16 to 0.34 +/- 0.11 (mL/100 mL tissue per minute)/(microgram/min) (P <.001). The decline in endothelium-dependent vasodilation was already evident by the fourth decade (age 30 to 39 years). Endothelium-independent vasodilation did not change with age. Age, total cholesterol, and low-density lipoprotein cholesterol were univariate predictors of endothelium-dependent vasodilation. Age remained the most significant predictor of endothelium-dependent vasodilator responses by multiple stepwise regression analysis. From these observations, it can be concluded that endothelium-dependent vasodilation declines steadily with increasing age in healthy human subjects. Age is a strong univariate and multivariate predictor of endothelium-dependent vasodilation. This finding may be a marker for more widespread endothelial dysfunction.

Diagnosis of micrometastases by the amplification of tissue-specific genes

Micrometastases of solid tumors are most commonly detected by immunocytochemistry using monoclonal antibodies directed against tissue-specific gene products like cytokeratin-18 (CK-18) and the carcinoembryonic antigen (CEA). While CK-18 is a marker for epithelia in general, CEA is mainly employed in the detection of gastrointestinal and breast carcinomas. To improve the sensitivity and specificity of micrometastasis detection, we planned to establish polymerase chain reaction (PCR) assays for both markers. Here we provide strong evidence for the existence of a CK-18 pseudogene, since specific amplification (i) was readily obtained from healthy bone marrow donors, (ii) did not require reverse transcription of CK-18 mRNA and (iii) was not abolished by RNase treatment. Using a CK-18-specific probe, Southern blot analyses revealed identical-size fragments for both genomic DNA and a CK-18 cDNA after digestion with appropriate restriction enzymes. On the other hand, the amplification of CEA mRNA (i) was never observed in bone marrow samples of healthy donors or patients without solid tumors, (ii) required intact mRNA and the reverse transcriptase reaction, and (iii) could not be obtained after RNase treatment. In reconstitution experiments, single CEA-expressing tumor cells were reliably detected among 2 x 10(7) normal bone marrow cells. We conclude that, due to the presence of pseudogene(s), PCR-based detection systems are not readily suitable for CK-18, while the CEA mRNA amplification should provide a sensitive and specific test for the presence of ectopic, and hence presumed malignant, CEA-expressing cells in body fluids.

Sex hormones, lipoproteins, and vascular reactivity

The HDL-raising effect of estrogen replacement is mediated by an increase in HDL-apolipoprotein A-I production and not by a decrease in the clearance rate. Large-scale clinical trials have shown that medroxyprogesterone acetate removes most of the HDL-raising effects of concomitant estrogen treatment. Testosterone decreases HDL levels in both men and women. Lipoprotein (a) levels are reduced by estrogen replacement, but are not affected by medroxyprogesterone. The acute systemic administration of estrogen to postmenopausal women improves the endothelium-dependent vasodilation of coronary arteries and forearm resistance vessels. Usual doses of oral estrogen replacement therapy improve the endothelium-dependent and endothelium-independent vasodilator responses in the forearm in women who have risk factors for atherosclerosis. These effects may be mediated by an antioxidant action of estrogen.

Peripheral arterial-vascular disease in women: prevalence, prognosis, and treatment

Lower extremity atherosclerosis results in significant morbidity in women, particularly in women following the menopause. Up to 25% of women aged 55 to 74 years are affected by this disease. When noninvasive testing is used to determine the prevalence of lower extremity atherosclerosis, and men in this age group are equally represented. Cigarette smoking, diabetes mellitus, and menopause are risk factors for atherosclerosis of particular interest in women. The prevalence of cigarette smoking is rising rapidly among women, and diabetes appears to be a greater risk factor for atherosclerosis in women than in men. Risk factor reduction, in addition to an exercise program, are important parts of the treatment program for stable claudication. In both men and women with more severe symptoms, an ankle/branchial index (ABI) of less than 0.3 is associated with more severe symptoms, an ankle/brachial index (ABI) of less than 0.3 is associated with a poor prognosis. Men and women fare equally well following revascularization for severe peripheral atherosclerosis. However, there are some data to suggest that women may be offered peripheral revascularization at a lower rate.

Specific detection of carcinoembryonic antigen-expressing tumor cells in bone marrow aspirates by polymerase chain reaction

PURPOSE

To establish a sensitive assay for the specific detection of carcinoembryonic antigen (CEA)-expressing tumor cells in the bone marrow of patients with colorectal cancer and other CEA-positive carcinomas.

PATIENTS AND METHODS

A CEA-specific nested reverse transcriptase (RT) polymerase chain reaction (PCR) assay was developed and optimized using limiting dilutions of a CEA-positive cancer cell line mixed with normal bone marrow cell specimens. The optimized test was then used to examine bone marrow samples obtained from 15 patients with abdominal carcinomas (colorectal, n = 10; pancreatic, n = 3; gastric, n = 2) and six patients with breast cancer. Specificity was assessed by examination of 56 negative controls (malignant hematologic disease, n = 28; nonmalignant disease conditions, n = 5; healthy bone marrow donors, n = 8; normal peripheral-blood samples, n = 15). For 11 patients with abdominal carcinomas, immunostaining evaluations were performed using an anti-CEA and an anticytokeratin antibody, and the results compared with the nested PCR assay.

RESULTS

In the sensitivity calibration system, single CEA-expressing tumor cells were detected in 2 to 5 x 10(7) normal bone marrow cells. All 56 control samples failed to amplify. This demonstrates that mRNAs coding for highly homologous CEA-related antigens expressed by various lineages of blood cells do not interfere. Bone marrow samples from 10 of 15 patients with abdominal cancers and four of six breast cancer patients scored positive, indicating micrometastatic bone disease. Four of 11 samples from the gastrointestinal cancer patients were found to be positive by the PCR method, but were negative with the immunocytology method.

CONCLUSION

Since approximately 30% of the colorectal carcinoma patients that score negative in immunocytology staining of bone marrow samples have been reported to relapse, earlier diagnosis of the presence of malignant cells is needed. Our result that samples scoring positive in the described CEA-specific PCR test remained negative by two immunostaining methods suggests a higher sensitivity. We conclude that PCR amplification of CEA mRNA may lead to an earlier diagnosis of micrometastatic bone disease in patients with CEA-expressing carcinomas.

The combined treatment of congenital vascular defects

Eighty-one patients with a vascular malformation on the extremities were evaluated. In 32 patients the abnormality was localised in the upper and in 49 in the lower extremity. Signs, symptoms, treatment modalities and long-term results were tabulated. In the upper extremity pain was the most frequent presenting symptom. Three types of malformation were distinguished: purely venous, venous with microshunts and malformations with macroshunts. The treatment of the first group consisted of excision of varices and superficial naevi, in the second group the combined treatment of embolisation and excision was the treatment of choice, in the last group the selective embolisation without resection was most frequently done. The treatment was most successful in those cases, where there was a malformation with macrofistulas in the shoulder-region or only a localised lesion, that could be excised. The first sign and symptom of the lower extremity was swelling or a naevus vasculosus. After inventarisation 4 groups of vascular malformations have been distinguished, the cavernous (venous), the cavernous (venous) with microshunts, the arteriovenous with macrofistulas and a purely venous (truncular) group, which we did not have in our patients with an upper extremity abnormality. Conservative treatment in purely venous malformations prevented progression, the combined treatment was successful in patients with an AV-malformation of the pelvis, or around the knee or in patients with a small excisable lesion.

IN CONCLUSION

the purely venous abnormality can be successfully treated with conservative measures, the arteriovenous malformation with macroshunts in pelvis and shoulder region should be embolised, and circumscript lesions excised with or without embolisation, depending on the character of the lesion.