Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research

A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.

Thyroid volume is associated with family history of thyroid disease in pregnant women with adequate iodine intake: a cross-sectional study in southern Brazil

Maternal euthyroidism is important for fetal neural development. For this reason, adequate iodine nutrition during pregnancy is an important public health objective and should be periodically revised. The objective of this study was to measure urinary iodine (UI) excretion and the factors associated with thyroid volume (TV), in a group of healthy pregnant women in southern Brazil, to evaluate iodine nutrition. The median UI of the 147 women was 224 microg/l (P25=164 microg/l and P75=286 microg/l). Serum levels of free T4 and thyroglobulin did not correlate with UI, but there was a weak inverse correlation between serum TSH levels and UI (r=-0.200; p=0.02). TV, calculated through ultrasound in 57 women, was significantly associated with family history of thyroid diseases (p=0.002) and BMI (p=0.03), but there was no association with UI, corrected or not for creatinine, serum free T4, TSH or thyroglobulin, current or past smoking, gestational age, parity or oral contraceptive.

CONCLUSIONS

The healthy pregnant women studied had adequate iodine intake. In this situation, the main thyroid size determinants are probably genetic factors.

[Ventricular assist in children]

We describe the use of the Berlin Heart biventricular mechanical assistance device, as a bridge to transplant in a two-years old child suffering from end stage dilated cardiomiopathy. Ventricular support lasted for 3,5 months and led to successful transplantation. We describe the clinical case, the protocols used as well as present indications, techniques and problems related to the use of mechanical heart support in children.

Evidence for the notch signaling pathway on the role of estrogen in angiogenesis

We have investigated the molecular mechanisms involved in 17 beta-estradiol-induced angiogenic pathway. We show here that 17 beta-estradiol promoted a 6-fold increase in Jagged1 expression and an 8-fold increase in Notch1 expression by cDNA arrays in breast cancer MCF7 cells. Interestingly, Jagged1 was abrogated by incubation with the estrogen antagonist, ICI182,780. A similar up-regulation of both Notch1 receptor and Jagged1 ligand was found in endothelial cells. Additionally, imperfect estrogen-responsive elements were found in the 5' untranslated region of Notch1 and Jagged1 genes. Treatment with 17 beta-estradiol also led to an activation of Notch signaling in MCF7 cells expressing Notch1 reporter gene or by promoting Jagged1-induced Notch signaling in coculture assays. Inoculation of MCF7 cells in 17 beta-estradiol-treated nude mice resulted in up-regulation of Notch1 expression as well as increased number of tumor microvessels in comparison to placebo-treated mice. Notch1-expressing endothelial cell cultures formed cord-like structures on Matrigel in contrast to cells expressing a dominant-negative form of Notch1, emphasizing the relevance of Notch1 pathway in vessel assembly. Finally, Notch1-expressing MCF7 cells up-regulated hypoxia-inducible factor 1 alpha gene, a well-known angiogenic factor that clustered with Notch1 gene. This study implicates Notch signaling in the cross talk between 17 beta-estradiol and angiogenesis.

Comparison of chickpea rhizobia isolates from diverse Portuguese natural populations based on symbiotic effectiveness and DNA fingerprint

AIMS

To test the hypothesis that differences in chickpea yields obtained in four distinct Portuguese regions (Beja, Elvas-Casas Velhas, Elvas-Estação Nacional de Melhoramento de Plantas (ENMP) and Evora) could be due to variation between the natural rhizobia populations.

METHODS AND RESULTS

Estimation of the size of the different rhizobial populations showed that Elvas-ENMP population was the largest one. Elvas-ENMP population also revealed a higher proportion of isolates carrying more than one plasmid. Assessment of genetic diversity of the native rhizobia populations by a DNA fingerprinting PCR method, here designated as DAPD (Direct Amplified Polymorphic DNA), showed a higher degree of variation in Elvas-ENMP and Beja populations. The symbiotic effectiveness (SE) of 39 isolates was determined and ranged 13-34%. Statistical analysis showed that SE was negatively correlated with plasmid number of the isolate.

CONCLUSIONS

The largest indigenous rhizobia population was found in Elvas-ENMP. DAPD pattern and plasmid profile analysis both suggested a higher genetic diversity among the populations of Elvas-ENMP and Beja. No relationship was found between SE of the isolates and their origin site.

SIGNIFICANCE AND IMPACT OF STUDY

The large native population, rather than the symbiotic performance of individual rhizobia, could contribute to the higher chickpea yields obtained in Elvas-ENMP.

Cyclo-oxygenase 2 expression is associated with angiogenesis and lymph node metastasis in human breast cancer

AIMS

Cyclo-oxygenases 1 and 2 (COX-1 and COX-2) are key enzymes in prostaglandin biosynthesis. COX-2 is induced by a wide variety of stimuli, and present during inflammation. COX-2 overexpression has been observed in colon, head and neck, lung, prostate, stomach, and breast cancer. In colon and gastric cancer, COX-2 expression was associated with angiogenesis. The aim of this study was to determine the relation between COX-2 expression and angiogenesis in breast cancer, and to correlate the expression of this enzyme with classic clinicopathological parameters.

METHODS

COX-2 expression was investigated by immunohistochemistry and western blotting analysis. The expression of COX-2 was then related to age, histological grade, nodal status, oestrogen receptor status, p53 expression,c-erb-B2 overexpression, mitotic counts, MIB-1 labelling index, apoptotic index, sialyl-Tn expression, transforming growth factor alpha expression, microvessel density, and disease free survival in 46 patients with invasive ductal breast carcinoma.

RESULTS

By means of immunohistochemistry, COX-2 expression was detected in eight of the 46 carcinomas studied. Western blotting showed COX-2 protein expression in the same breast tumours, but not in normal adjacent tissues. The density of microvessels immunostained with anti-F-VIII related antigen was significantly higher in patients with COX-2 expression than in those without expression (p = 0.03). In addition, COX-2 was significantly associated with the presence of sialyl-Tn expression (p = 0.02), lymph node metastasis (p = 0.03), a high apoptotic index (p = 0.03), and a short disease free survival (p = 0.03) in univariate analyses.

CONCLUSIONS

These data suggest that COX-2 expression is associated with angiogenesis, lymph node metastasis, and apoptosis in human breast cancer. Moreover, these results warrant further studies with larger series of patients to confirm the association with short disease free survival in patients with breast cancer.

[Analysis of mutations in genes BRCA1 and BRCA2 among patients with breast and ovarian cancer in northern Portugal and Galicia]

OBJECTIVE

To detect mutations in the BRCA1 and BRCA2 genes by means of the protein truncation test (PTT) in a population in northern Portugal and Galicia with breast and ovarian cancer.

DESIGN

Prospective study.

SETTING

Patients in northern Portugal and Galicia with family history of breast and/or ovarian cancer.Patients. A total of 76 women with family history of breast cancer according to the BCLC criteria (Breast Cancer Linkage Consortium) were studied at IPATIMUP.

MAIN RESULTS

Five cases (6.5%) with changes in the normal sequence in genes BRCA1 and BRCA2 were identified; three of these mutations occurred in the gene BRCA1 and the other two in the gene BRCA2. Two out of the three mutations found in the gene BRCA1 were de novo mutations. Changes detected in the normal sequence in the gene BRCA2 were mutations reported for the first time among the study population, according to the information obtained through the BCIC database (Breast Cancer Information Core).

CONCLUSIONS

This was the first study in detecting individuals carrying mutations in the susceptibility breast cancer genes BRCA1 and BRCA2 among the population of northern Portugal and Galicia.

Management of acute myocardial infarction in Portugal. Results of a nationwide survey

The management of acute myocardial infarction (AMI) has improved markedly over the last decade. Large-scale trials have produced a large amount of evidence, and recommendations and guidelines have been established. Whether and to what extent these data have influenced everyday practice on a nationwide scale remains to be ascertained. The present observational prospective, registry was designed to assess current practice in in-hospital management of AMI in Portugal. For a period of 3 months (February to May, 1999), 44 centers, distributed all over the country, Atlantic islands included, enrolled 1372 cases of AMI corresponding to 1366 patients (996 male, mean age 65 +/- 13 years; 370 female, mean age 72 + 11 years; p < 0.0001). Non-ST segment elevation infarcts were present in 26% of cases. In-hospital mortality was 11.2% (154 pts, mean age 74 +/- 10 years).

RESULTS

519 pts (37.8%) were managed with reperfusion therapy, 413 of them with fibrinolysis (30.1%) and 106 with primary PTCA (7.7%). Besides the invasive procedures performed within the first few hours after admission, coronary angiography was performed in 327 more pts (26.1%); 143 pts were revascularized (PTCA in 117 pts and CABG in 26) and 96 more pts were discharged and referred for further revascularization. The total number of pts given or referred for a revascularization procedure (including the primary treatment) was 316 (20.6%). Besides reperfusion therapy the most commonly used drugs for secondary prevention were aspirin in 91%; ACE inhibitors in 63%; beta-blockers in 45%; and statins in 28%. Based on the results of this nationwide survey it can be concluded that the main international guidelines and recommendations for the medical management of acute myocardial infarction are generally being applied in Portugal.

[Analysis of mutations in the BRCA1 gene in patients with cancer of the breast and/or the ovary in Portugal]

Germline mutations in the BRCA1 gene confer an increased susceptibility to breast and ovarian cancer. Approximately 460 distinct mutations were founded scattered throughout the whole gene. However, several mutations were detected repeatedly in individuals of the same ethnic origin. There are no systematic studies concerning mutations in BRCA1 gene in Portugal. The aim of this study is to identify mutations inh this gene in patients with breast and/or ovarian cancer of Portuguese origin. Thirty-three cases of breast cancer and 3 of ovarian cancer were selected according to early age of onset and family history. Mutation screening of this gene was done by Protein Truncation Test (PTT) and Fragment analysis. Two de novo mutations were identified: 1) A frameshift mutation localised in exon 11 of BRCA1, was identify by the two techniques in an ovarian cancer case. Direct sequential revealed a deletion of 4 nucleotides (3444delAAAT); 2) An alteration in intron 18 (IVS 18 + 80delT) was observed in a breast cancer case. This is probably the first description of mutations in a series of patients with breast and/or cancer in the Portuguese population. The mutations identified in this study have not been previously described in other populations according to the Breast Cancer Information Core web site.

Unstable angina: individualized stratification and prognosis

OBJECTIVE

To analyse the methodology of risk stratification and the prognosis of patients admitted with unstable angina.

POPULATION AND METHODS

This retrospective study involved a population of 68 patients (43 males and 25 females with a mean age of 65.8 +/- 9.8 years) consecutively admitted for suspected unstable angina during the year of 1996. Thirty six patients (52.9%) had angina at rest, 13 patients (19.1%) had both exertional and rest angina, 9 patients (13.2%) crescendo angina, 6 patients (8.8%) new onset exertional angina (less than 1 month), and 4 patients (5.8%) post-infarction angina (less than 2 weeks). The risk stratification was individualized. The coronary angiography (35 patients) was only performed when the medical therapy failed in patients with recurrent angina, or with proved ischemia after an exercise test and/or thallium 201 stress scintigraphy. Thirteen patients (19.1%) did not undergo these tests (advanced age and or bad general condition, or refusal). The follow-up of patients with and without ST-T changes was compared, as well as those revascularized versus non-revascularized. It was possible to achieve a mean follow-up of 13.7 +/- 6.2 months (3 to 25 months).

RESULTS

The exercise test and/or thallium-201 stress scintigraphy were positive for myocardial ischemia in 28 pts (41.1%) and negative in 7 patients (10.2%). The coronary angiography revealed three-vessel coronary artery disease in 18 patients (26.4%), one vessel disease in 11 patients (16.1%) and two-vessel disease in 5 patients (7.3%). One patient had normal coronary arteries. Medical therapy was the initial approach. Coronary surgery was urgently performed in 3 patients and coronary angioplasty in 5 patients for refractory unstable angina. In the whole group coronary artery surgery was undertaken in 14 patients (20.5%) and coronary angioplasty in 12 patients (17.6%). A mean follow-up of 13.7 +/- 6.2 months was obtained in the 68 patients. During this period 6 patients (8.8%) died due to cardiac causes and 16 patients (23.5%) were readmitted: 8 patients (11.7%) for unstable angina, 5 patients (7.3%) for congestive heart failure and 3 patients (4.4%) for myocardial infarction. Fifty two patients (76.4%) remained free of cardiac events. The patients with transitory ST-T changes had more cardiac events (unstable angina, myocardial infarction, mortality) than the patients without ECG changes (13/30 vs 2/30, p = 0.003). When the revascularized patients were compared to the non revascularized no significant differences were observed regarding myocardial infarction and mortality, however revascularized pts had a less significant incidence of rehospitalization for unstable angina (0/26 vs 8/42 p = 0.02).

CONCLUSIONS

An individualized strategy can be effective in pts with unstable angina. In this study 76.4% of patients remained free of cardiac events during the follow-up, 23.6% had severe cardiac events and the cardiac mortality was 8.8%. The patients with transitory ST-T changes had more cardiac events and worse prognosis. No patients significant difference was observed in the revascularized versus non revascularized patients for myocardial infarction and mortality; however, the revascularized patients had less significant incidence of rehospitalization for unstable angina.

Microsatellite instability in medullary breast carcinomas

Microsatellite instability (MSI) has been reported to occur in a wide variety of sporadic tumours, such as colorectal and gastric cancers. MSI positivity has been associated with a particular clinico-pathologic profile, including the presence of abundant lymphoid infiltration, poor differentiation and a relatively good outcome for the patients. Since medullary breast carcinomas (MBCs) share these clinico-pathologic features with the MSI-positive tumours described above, we evaluated MSI in this particular histologic type of breast cancer. DNA of 24 MBC cases was extracted from formalin-fixed, paraffin-embedded tissue. The presence of MSI was analysed using BAT-26. We also searched mutations in 2 target genes: TGF-beta RII and BAX. Five cases of the series were also analysed for 1 (CA) dinucleotide tandem repeat sequence (D1S158), 8 tetranucleotide repeat sequences (D3S1358, D5S818, D7S820, D8S1179, D13S317, D21S11, FGA and VWA) and 1 pentanucleotide repeat (dAAAAT), localized in intron 1 of p53 gene. We found 2 carcinomas (8.3%) with BAT-26 instability. None of the cases had mutations in the "target genes", TGF-beta RII and BAX, including the 2 cases with BAT-26 instability. No MSI was observed using the panel of tetra- and pentanucleotide markers. Loss of heterozygosity was found in some loci. No significant difference in mean MIB-1 index according to RER status was observed. The low frequency of MSI in MBC is similar to that of other histologic types of breast cancer. Although MBCs share some clinico-pathologic features with colorectal and gastric carcinomas, which exhibit a high frequency of MSI, the underlying genetic events leading to this breast tumour are different from those leading to tumours of the digestive tract.

P53 in breast carcinomas: association between presence of mutation and immunohistochemical expression using a semiquantitative approach

The aim of this study was to evaluate the concordance between the presence of p53 mutations in breast carcinomas expressing the protein by immunohistochemistry. A series of 60 breast carcinomas was evaluated by immunohistochemistry using monoclonal antibodies against p53 protein (DO 7 and PAb 1801). Twenty cases classified as being positive for p53 according to the current approach (if 5% or more of neoplastic cells contained reaction product in the nucleus) were used for molecular studies. These cases were re-assessed semi-quantitatively using a scoring system based on intensity and percentage of stained cells. DNA was phenol-chloroform extracted from microdissected normal and tumour cells obtained from formalin-fixed, paraffin-embedded tissue sections. Mutations in the p53 gene were analysed by SSCP (single strand conformational polymorphism) with primers covering exons 2-3 to 11. Ten out of the 20 p53-positive cases presented mutations detected by SSCP analysis. Mutations have been found in several exons ranging from exon 4 to exon 10. We observed a positive relationship between the presence of mutations and immunohistochemical evaluation of p53 protein expression using a semiquantitative scoring system. All cases with more than 2/3 stained tumour cells and strong intensity of staining exhibited p53 mutations. At variance, no p53 mutations were found in cases with less than 1/3 stained tumour cells and moderate intensity of staining. Therefore, only the identification of positivity for p53 detected by immunohistochemistry did not always reflect the detection of p53 mutations in breast cancer, however the use of a semi-quantitative approach seems to be useful as an indicator of the presence of mutation.

Bilateral apocrine carcinoma of the breast. Molecular and immunocytochemical evidence for two independent primary tumours

Apocrine carcinoma is an uncommon variant of breast cancer. The frequency of bilaterality in patients who have apocrine carcinoma in one breast is not significantly different from that for bilateral mammary carcinomas in general, but bilateral apocrine carcinomas are very uncommon. We report on a bilateral apocrine carcinoma of the breast in a 74-year-old woman. The apocrine differentiation in both tumours was confirmed by the positivity of the cytoplasmic granules for PAS after diastase digestion and immunoreactivity for GCDFP-15 and sialyl-Tn. The tumour in the right breast showed immunohistochemical expression of p53, and a mutation was demonstrated by PCR-SSCP; the tumour in the left breast was negative for p53 on immunohistochemistry, and no mutation was found at the molecular level. c-erbB2 expression was not detected in the right tumour but there was overexpression (at the cell membrane) in the left tumour. Both tumours were aneuploid: the right tumour displayed multiple stemlines, whereas the left tumour had a triploid profile. Using the fluorescence in situ hybridization technique we demonstrated that both tumours displayed chromosome 17 polysomy and numerical abnormalities of chromosome 1, polysomy in the right and monosomy in the left tumour. We conclude that the two tumours are probably independent, as are most bilateral carcinomas of the breast.

PCR amplification of DNA obtained from archived hematoxylin-eosin--and giemsa-stained breast cancer aspirates

The study of DNA abnormalities in fine-needle aspiration (FNA) specimens for breast cancer could be helpful in improving the capacity of diagnosis and specially to obtain prognostic or predictive information. The aim of the present study was to verify whether it is possible to perform molecular analysis in slides of breast cancer FNA specimens. previously stained by hematoxylineosin (H&E) and Giemsa, stored at least for 3 years. For this purpose, 10 cases of FNA obtained from breast cancer patients diagnosed between 1993 and 1994 in our institute were used. Five cytologic smears were alcohol-fixed and stained with H&E. The other five were air-fixed and Giemsa stained. DNA was isolated from the cytologic smears and amplified by using radioactive polymerase chain reaction (PCR) aimed at BAT-26 marker. Our results demonstrate that archived stained smears prepared for cytologic examinations can be used for molecular analyses by using a PCR amplification method. DNA could be isolated and PCR amplified independently of the prior fixation and staining procedures. So, we conclude that the application of molecular biology techniques to the existing archival smears may become a valuable tool to detect genetic changes in samples from breast cancer aspirates.

Reduction in temporal N-acetylaspartate and creatine (or choline) ratio in temporal lobe epilepsy: does this 1H-magnetic resonance spectroscopy finding mean poor seizure control?

BACKGROUND

Proton magnetic resonance spectroscopy (1H-MRS) is a potentially useful tool in the in vivo investigation of brain metabolites in intractable temporal lobe epilepsy (TLE). Focal N-acetylaspartate (NAA) reductions have been correlated with mesial temporal sclerosis (MTS) in surgically resected epileptogenic foci.

OBJECTIVE

To evaluate the abnormalities in the metabolites NAA, creatine+ phosphocreatine (Cr), and choline containing compounds (Cho) in the temporal lobe of medically refractory patients with temporal lobe epilepsy, seizure free patients with temporal lobe epilepsy, and normal controls.

PATIENTS AND METHODS

Ten refractory patients, 12 seizure free patients with temporal lobe epilepsy, and 10 age matched normal controls were studied by 1H-magnetic resonance spectroscopy. All patients had consistently unilateral temporal EEG abnormalities and a normal brain MRI. Proton MR spectra were obtained from an 8 ml volume in the medial temporal lobes in patients with temporal lobe epilepsy (ipsilateral to EEG foci) and the normal controls. The signals measured were expressed in terms of NAA/Cr, NAA/Cho, and Cho/Cr.

RESULTS

When compared with seizure free patients with temporal lobe epilepsy and normal controls, the 10 refractory patients with temporal lobe epilepsy had a lower mean (SEM) NAA/Cr ratio (1.65 (0.53) v 2.62 (0.60), and 2.66 (0.73); p<0.002 and p<0.006) and a lower mean NAA/Cho ratio (1.59 (0.79) v 2.83 (1.33) and 2.58 (0.67); p<0.02 and p<0.007). Furthermore, the two patients showing the lowest NAA/Cr ratios (1.47 and 1.73) in the seizure free group had had a past period of poor seizure control.

CONCLUSIONS

There were reduced temporal NAA/Cr and NAA/Cho ratios, suggesting neuronal loss or damage, associated with past or present poor seizure control in the patients with temporal lobe epilepsy, but it does not exclude the possibility of a future complete seizure control (seizure free patients with temporal lobe epilepsy at the time of 1H-MRS). This study warrants further 1H-MRS investigation with a larger series of patients with temporal lobe epilepsy.