UV excimer laser photoablation was used to micro-machine polymer substrates not only to drill microchannel structures but also to change the surface physical properties of the substrates. We first describe how UV laser photoablation can be used for the patterning of biomolecules on a polymer and discuss parameters such as surface coverage of active antibodies and equilibration time. Secondly, we show how to design a single-use capillary electrophoresis system comprising an on-chip injector, column and electrochemical detector. The potential of this disposable plastic device is discussed and briefly compared to classical systems. Finally, preliminary results on protein separation by isoelectric focusing on a disposable microchip are presented.

Adsorption↗

PubMedDate not supplied

Purine metabolism and B-lymphocyte development in the chicken bursa of fabricius.

The activity of three enzymes involved in the salvage pathway of purine nucleosides--purine nucleoside phosphorylase (PNP), xanthine dehydrogenase (XDH), and hypoxanthine-guanine phosphoribosyl transferase (HGPRT)--was investigated in cellular fractions of the chicken bursa of Fabricius differentially enriched in epithelial cells or lymphocytes. Markedly increasing levels of PNP and XDH were observed along with the enrichment in epithelial cells together with a slight, though significant, decrease in HGPRT activity. By contrast, a dramatic fall in PNP and XDH activities was detected along with the enrichment in lymphocytes together with a slight, though significant, increase in HGPRT activity. This sharply different distribution of the three enzymes, all sharing hypoxanthine as a substrate, clearly indicates that lymphocytes preferentially channel hypoxanthine into the salvage and interconversion pathways, phosphorylating it to IMP, while epithelial cells rapidly catabolize such a purine base to uric acid. Moreover, epithelial cells, unlike lymphocytes, are able to retain high intracellular levels of both hypoxanthine and inosine. These results support the possibility that epithelial cells contribute to the normal development of bursal lymphocytes by supplying such actively proliferating cells with purine rings and at the same time by preventing them from accumulating potentially toxic high levels of purine nucleotides being able to rapidly eliminate excess hypoxanthine as uric acid from the bursa environment into the bloodstream.

Animals↗

PubMedDate not supplied

Anophthalmia and benomyl in Italy: a multicenter study based on 940,615 newborns.

Following the report on clusters of anophthalmia and microphthalmia in England and Wales and their possible relation to the pesticide Benomyl, we analyzed the situation in Italy for the period 1986 to 1990 using data from the Italian registries of congenital malformations and national data on Benomyl use. Of 940,615 consecutive births, 33 cases of clinical anophthalmia and 78 cases of microphthalmia were reported (birth prevalence: 0.35 and 0.83/10,000). Birth prevalence by region for 18 of Italy's 20 political regions was evaluated for the two malformations, grouped together after exclusion of defects associated with chromosomal anomalies, no dishomogeneity in space or time among registries or among regions was observed for the study period. In no region was a statistically significant difference identified between observed and expected overall birth prevalence. Correlation analysis between the prevalence of micro/anophthalmia and Benomyl use by region showed a negative, nonsignificant coefficient, and an inverse correlation was found when the 18 regions were divided into four groups by increasing levels of Benomyl use. Parental occupation in agriculture did not seem to be associated with micro/anophthalmia when compared to a control group affected with isolated prearicular tags (odds ratio 0.63; CL 0.07-2.52). On the basis of these results, though the limits intrinsic to ecologic correlation studies must be taken into account, an association between Benomyl use and congenital micro/anophthalmia appears to be unlikely.

Anophthalmos↗

PubMedDate not supplied

Acrodermatitis enteropathica-like eruption: a sign of malabsorption in cystic fibrosis.

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Acrodermatitis↗

PubMedDate not supplied

Is occupationally induced exposure to radiation a risk factor of thyroid nodule formation?

The prevalence of thyroid nodules was studied with ultrasonography in a group of male hospital workers (n = 44) who had been exposed occupationally to x-rays. This group was compared with a group of nonexposed workers (n = 88) who were age- and sex-matched with the exposed workers. Thyroid nodules were detected in 18 (41%) of the exposed workers, compared with 11 (13%) of the nonexposed controls. Both groups were subdivided with respect to age (i.e., 30-39 y, 40-49 y, 50-59 y), and there was a higher and significant relative risk for thyroid nodule formation in the exposed group. We also divided the groups into subgroups according to levels of exposure (i.e., nonexposed, exposed for < 20 y, and exposed for > 20 y), and a significant result was obtained with the linear-trend chi-square test. The preliminary results of our study suggest that occupationally induced exposure to radiation may be a risk factor for thyroid nodule formation.

Adult↗

PubMedDate not supplied

MSH2 splice site mutation and endometrial cancer.

Hereditary nonpolyposis colorectal cancer (HNPCC) is an inherited syndrome of cancer susceptibility caused by germ line mutations of genes participating in mismatch repair (MMR). Carriers of MMR gene mutations have an increased risk of colorectal cancers and cancer of other organs. Tumors of the endometrium represent the most frequent extracolonic malignancies in HNPCC. It has been suggested that women harboring MMR gene mutations have a higher risk of endometrial cancer than of colon cancer. Here, we describe an HNPCC patient with early-onset endometrial cancer and a strong familial history of endometrial tumors who harbored a germ line MSH2 splice site mutation (IVS9_2A>G). This mutation was responsible for abnormal messenger RNA processing, leading to the introduction of a premature stop signal and to the expression of a truncated MSH2 protein. In addition, the same mutation was associated with loss of MSH2 protein expression, high microsatellite instability, and PTEN inactivation. Although a direct relationship between the endometrial cancer susceptibility and the MSH2 mutation we found cannot be established, our observations, consistent with the work of other authors, suggest the involvement of germ line MSH2 abnormalities in endometrial tumor development and support the case for endometrial cancer screening in women from HNPCC families.

Adenocarcinoma↗

PubMedDate not supplied

TGF-alpha mRNA expression in renal organogenesis: a study in rat and human embryos.

The peptides belonging to the epidermal growth factor (EGF) family play a significant role in kidney development by binding the EGF receptor. Transforming growth factor-alpha (TGF alpha), a member of this family, is thought to be the fetal ligand of the EGF receptor. The present study aims to localize the TGF alpha transcripts in rat and human embryonic kidneys using a nonradioactive in situ hybridization method on paraffin-embedded embryonic samples. The results obtained in this study, beside demonstrating the usefulness of the nonradioactive technique for the detection of TGF alpha mRNA in paraffin sections, allowed TGF alpha-producing cells to be seen in developing kidneys. TGF alpha mRNA and its respective peptide were found in the primitive mesonephric structures and within metanephric blastema and ureteric bud cells. The presence of the TGF alpha gene transcript in the developing rat and human kidney suggests that the TGF alpha peptide is of embryonic origin and that it may contribute to renal organogenetic processes together with other growth factors.

Animals↗

PubMedDate not supplied

Italian multicenter study on reversible cerebral ischemic attacks: III--Influence of age and risk factors on cerebrovascular atherosclerosis.

The influence of age and other risk factors (history of hypertension and diabetes, cigarette smoking, dyslipidemia) on cerebral atherosclerosis was studied in 462 patients with RIA who had cerebral angiography. The degree of atherosclerosis was quantified using extracranial and intracranial cerebrovascular scores (ECS, ICS) based on the number and severity of the lesion in 11 extracranial and 21 intracranial arterial segments. Thirty-six percent of the patients under age 45 had a normal angiogram compared with 17% of the patients over 45. In the subgroup of patients with abnormal angiogram the mean ECS and ICS vascular scores were not significantly different in the two age groups. Cigarette smoking was the only risk factor to show a strong association with the extracranial score, and it was independent of the effect of age and other risk factors.

Adult↗

PubMedDate not supplied

The Italian Multicenter Study of reversible cerebral ischemic attacks: IV--Blood pressure components and atherosclerotic lesions.

Utilizing the initial BP assessment in the 462 patients who entered the Italian Multicenter Study of reversible cerebral ischemia, an analysis of the effect of each BP component in respect of presence, extent and severity of atherosclerotic lesions, as displayed by angiography, was carried out separately for lesions located at either intra- or extracranial level. In a multivariate statistical model, among the following variables: sex, age, systolic BP, diastolic BP, cholesterol and smoking, systolic BP was found the best predictor of extent and severity of atherosclerotic lesions at extracranial level. None of the same variables was predictive of the severity of intracranial atherosclerosis. The results of this clinical study may confirm the indication, coming from physiopathologic observations, of a predominant role of systolic hypertension in the process of maintenance and acceleration of atherosclerosis in the large pre-cerebral arteries.

Age Factors↗