PubMed Health⌕ Search

Biomedical subjects

M Paz

Publications and source records attributed to M Paz.

At least 19 recordsLinked to original sources
PubMed2003

The impact of early testicular sperm extraction or cryopreservation on the outcome of intracytoplasmic sperm injection--a randomized controlled study.

PURPOSE: To compare the outcome of sperm extraction 24 h before ovum pickup and on the day of oocyte retrieval. METHODS: A controlled study was performed to compare the outcome of 90 sperm extractions and in vitro sperm injection cycles performed in 54 patients. RESULTS: Available fresh sperm for the sperm injection procedure and cryopreservation obtained on the day of ovum pickup were similar to sperm collected 1 day before (33.3% vs 39.4%, respectively). Fertilization rate obtained with fresh sperm was also similar (48.9% vs. 54%), respectively. Clinical pregnancy rate was 38% vs. 22% per embryo transfer, respectively (P = 0.235). When comparing an additional 24 cycles with cryopreservation of sperm retrieved on the day of ovum pickup, as well as a day previously, no significance was noted in the parameters. CONCLUSIONS: Sperm retrieved 24 h before oocyte retrieval and used as fresh or frozen-thawed for sperm injection are as effective as those used on the day of ovum pickup.

Adult↗
PubMed2001

[Subclinical carotid atherosclerosis in patients with coronary disease].

BACKGROUND: B-mode ultrasonography is a simple and valid method to evaluate subclinical atherosclerosis of the major superficial arteries. The aim of this study was toknow by this technique the prevalence of carotid atherosclerosisin patients with coronary disease and related factors. PATIENTS AND METHOD: In 232patients (205 men and 27 women; age: mean [standard deviation]59 [8] years) with coronary disease, intima-media thickness (IMT),presence and number of atheroma plaques in carotid arteries wereevaluated by B-mode ultrasonography. Controls were 50 healthy subjects whose age was not different from patients. Carotid atherosclerosis was considered when IMT was higher than mean plus two standarddeviations of control values, and/or existence of atheroma plaques. RESULTS: Carotid IMT wasincreased in patients compared to controls 0.82 [0.22] vs 0.62[0.12] mm; p < 0.001) and there were more patients with plaques(67 vs 20%; p < 0.001). Carotid atherosclerosis was found in170 patients and 11 controls (73 vs 22%; p < 0.001). By multivariate analysis, carotid atherosclerosis was associated with age (oddsratio: 1.05; 95% confidence interval [CI], 1.01-1.09) and smoking(odds ratio, 2.11; 95% CI: 1.04-4.26). The presence of more thanone plaque was associated with levels of low-density-lipoprotein(LDL)-cholesterol (odds ratio, 1.01; 95% CI, 1.00-1.02). CONCLUSIONS: In the patients with coronary disease, prevalence of subclinical carotid atherosclerosisis very high (73%), and it is associated with age and smoking. The advanced stage of atherosclerosis, evaluated by the existence of more than one plaque, is correlated with LDL-cholesterol levels.

Aged↗
PubMed2001

Soybean genomic survey: BAC-end sequences near RFLP and SSR markers.

We are building a framework physical infrastructure across the soybean genome by using SSR (simple sequence repeat) and RFLP (restriction fragment length polymorphism) markers to identify BACs (bacterial artificial chromosomes) from two soybean BAC libraries. The libraries were prepared from two genotypes, each digested with a different restriction enzyme. The BACs identified by each marker were grouped into contigs. We have obtained BAC- end sequence from BACs within each contig. The sequences were analyzed by the University of Minnesota Center for Computational Genomics and Bioinformatics using BLAST algorithms to search nucleotide and protein databases. The SSR-identified BACs had a higher percentage of significant BLAST hits than did the RFLP-identified BACs. This difference was due to a higher percentage of hits to repetitive-type sequences for the SSR-identified BACs that was offset in part, however, by a somewhat larger proportion of RFLP-identified significant hits with similarity to experimentally defined genes and soybean ESTs (expressed sequence tags). These genes represented a wide range of metabolic functions. In these analyses, only repetitive sequences from SSR-identified contigs appeared to be clustered. The BAC-end sequences also allowed us to identify microsynteny between soybean and the model plants Arabidopsis thaliana and Medicago truncatula. This map-based approach to genome sampling provides a means of assaying soybean genome structure and organization.

Algorithms↗
PubMed2000

Total arsenic, lead, and cadmium levels in vegetables cultivated at the Andean villages of northern Chile.

Various vegetables (broad beans, corn, potato, alfalfa and onion) were sampled in northern Chile, Antofagasta Region. They are the basis of human nutrition in this region and of great relevance to human health. This region is characterized by volcanic events (eruptions, thermal springs, etc.). Most of the vegetables cultivated in this area enter the local markets for a population of approximately 4000 people, whose ancestors were mainly atacameños and quechuas (local indigenous people). The cadmium and lead in these foods was determined by differential pulse anodic stripping voltammetry (DPASV). Results indicate that the highest concentration of Pb and Cd are in the potato skin, while the edible part of the potatoes contained a lower concentration of these metals. The INAA analyses of As in the vegetables from Socaire and Talabre, two towns located close to active volcanoes (e.g. Lascar), show a very high As content: 1850 microg/kg in corn (Socaire) and 860 microg/kg in potatoes (+ skin) (Talabre). These values exceed the National Standard for arsenic (500 microg/kg) by approximately 400% and 180%, respectively. In general, the data show a concentration of Pb greater than Cd with the potential for some vegetables to accumulate heavy metals, The values, expressed in fresh weight, vary from 0.2 to 40 microg/g for Cd and from 0.6 to 94 microg/g for Pb. These concentration intervals, except that of arsenic, are within the recommended standards in the Food Sanitary Regulation (Decree 977), which, expressed as fresh weight, must be equal to or smaller than 500 microg/kg for Pb. There is no legal standard for Cd.

Arsenic↗
PubMed1999

Potentiation of haloperidol catalepsy by microinjections of nicotine into the striatum or pons in rats.

It was reported that systemic administration of nicotine in rats potentiated the cataleptogenic effect of haloperidol. Moreover, addition of nicotine to the treatment with haloperidol in patients suffering from the Gilles de la Tourette's syndrome resulted in reduction in frequency and severity of tics. In the present article we report results of experiments aimed at investigating the role of striatum and pontine reticular formation in the synergistic relations between the two drugs. Nicotine was microinjected directly into the striatum or pontine reticular formation of rats and its cataleptogenic effects were studied when given alone or in combination with systemical injections of haloperidol. It was found that nicotine has cataleptogenic effects when microinjected both into the striatum and pontine reticular formation. The synergism between the two drugs occurred both after microinjections into the striatum and pontine reticular formation.

Animals↗
PubMed1998

Cis/Trans Reactivity: Epoxy-Amine Systems.

The reactivities of cis and trans isomers of 1,2-diaminocyclohexane (1,2-DCH)/epoxy resin were studied separately. We found that the primary amine hydrogen disappears in both isomers at a similar rate when they react with an epoxy resin. However, the formation of tertiary amines differs considerably. The reactivity of the second amine hydrogen for the trans isomer is greater than that for the cis isomer, and this difference is observed as the reaction proceeds. The main reason for the slower disappearance of the cis secondary amine is steric hindrance and this fact is observed in the preexponential factors, glass transition temperatures (Tg), and ratio of rate constants of secondary to primary amine (R). The reaction was followed by Fourier transform infrared spectroscopy in the near-infrared range. The values of Tg were obtained by differential scanning calorimetry.

Journal Article↗
PubMed1998

Characterisation of Trypanosoma cruzi populations by DNA polymorphism of the cruzipain gene detected by single-stranded DNA conformation polymorphism (SSCP) and direct sequencing.

Fifty fresh isolates of Trypanosoma cruzi from Triatoma dimidiata vectors and 31 from patients with Chagas' disease were analysed for DNA polymorphisms within the 432-bp core region of the cruzipain gene which encodes the active site of cathepsin L-like cystein proteinase. The cruzipain gene showed signs of polymorphism consisting of four different DNA sequences in Central and South American isolates of T. cruzi. The PCR fragments of Guatemalan isolates could be divided into three groups, Groups 1, 2 and 3, based on different patterns of single-stranded DNA conformation polymorphism. All of the strains isolated from Brazil, Chile, and Paraguay, except for the CL strain, showed a Group 4 pattern. Two to four isolates from each group were analysed by cloning and sequencing. A silent mutation occurred between Groups 1 and 2, and five nucleotides and two aa substitutions were detected between Groups 1 and 3. The DNA sequence of Group 4 contained five nucleotides and one aa substitution from Group 1. All of the DNA sequences corresponded well with the single-stranded DNA conformation polymorphism. The Group 1 isolates, the majority in the Guatemalan population (70/81, 86.4%), were isolated from both triatomines and humans, but Group 3 were isolated only from humans. Moreover, the Group 2 isolates were detected only in triatomine vectors (9/50; 18%), but never in humans (0/32, P<0.05) suggesting that this group has an independent life-cycle in sylvatic animals and is maintained by reservoir hosts other than humans.

Amino Acid Sequence↗
PubMed1998

[Infection and coronary atherosclerosis: the role Chlamydia pneumonia].

The role of inflammatory reactions in the pathogenesis of atherosclerosis is widely accepted. Recently, an increasing body of evidence has linked infections to atherosclerosis. It is hypothesized that infections could interact with other risk factors of vascular disease, enhancing the endothelial damage and the production of atherosclerotic plaques. Several different infectious agents have been related to the atherosclerosis genesis: mainly herpesvirus, Helicobacter pylori and Chlamydia pneumoniae. Several lines of evidence strongly link C. pneumoniae to atherosclerosis. Consequently, several studies evaluating the effectiveness of antibiotic treatment in the reduction of cardiac ischemic events in patients with C. pneumoniae seropositivity have been performed. These studies support a causative role for C. pneumoniae. This article reviews the recent evidence linking infections to atherosclerosis, with emphasis on the role of C. pneumoniae on the atherosclerotic plaque.

Chlamydia Infections↗
PubMed1997

Pontine reticular formation is involved in catalepsy produced by cholinergic drugs.

Bilateral kainic acid lesions of the ventro-medial (VM) thalamic nucleus of rats which greatly reduced the catalepsy produced by haloperidol (2 mg/kg i.p.) not only did not reduce, but even enhanced, the cataleptogenic effect of eserine (1 mg/kg i.p.) and arecoline (30 mg/kg i.p.). This finding is in accord with former conclusions that catalepsy produced by cholinergic drugs does not depend on striatal mechanisms. In rats with kainic acid lesions of the VM thalamic nucleus, and similarly in intact, non-lesioned rats, systemic administration of eserine and arecoline potentiated the catalepsy produced by microinjections of carbachol (2 microg) into the pontine reticular formation (PRF). Atropine microinjected bilaterally into the PRF attenuated the cataleptogenic effect of eserine and arecoline i.p. We suggest that the PRF is a site at which systemically given cholinergic drugs act to produce catalepsy.

Animals↗
PubMed1996

The role of endogenous nitric oxide in the response of coronary blood flow to tachycardia.

BACKGROUND: The role of endogenous nitric oxide as mediator of flow-dependent dilation is well established. However, its role in the adaptation of coronary blood flow to tachycardia is less well defined. This study was designed to determine whether nitric oxide is a mediator in pacing-induced hyperaemia. METHODS: Twenty pigs were instrumented for coronary blood flow, aortic pressure and atrial pacing measurements. Their heart rate was increased by 20 beats every 5 min. Coronary blood flow was measured basally and at each pacing interval before and after each of the following interventions: intracoronary saline infusion (n = 6), N omega-nitro-L-arginine methyl ester infusion (L-NAME, 20 micrograms/kg per min intracoronarily, n = 9) and infusion of L-NAME plus L-arginine (0.3 mg/kg per min intracoronarily, n = 5). RESULTS: The coronary peak flow increased with atrial pacing. The maximum increase in coronary blood flow with pacing was significantly reduced after infusion of L-NAME (159 +/- 33 versus 143 +/- 30%), whereas no change was observed in the saline group (163 +/- 28 versus 172 +/- 29%). However, it increased significantly in the group receiving L-NAME plus L-arginine (147 +/- 29 versus 182 +/- 40%). CONCLUSIONS: In the pig, the increase in coronary blood flow and therefore the vasodilation of the microvasculature that accompanies tachycardia depend, partly, on the release of endogenous nitric oxide.

Animals↗
PubMed1996

Improvement of exercise-induced ischaemia and myocardial perfusion after aminophylline.

BACKGROUND: Previous studies have suggested that aminophylline improves exercise-induced ischaemia by preventing the redistribution of the coronary flow from ischaemic to non-ischaemic myocardium. The purpose of the study was to assess whether aminophylline improves myocardial perfusion in zones supplied by collateral circulation. METHODS: Twenty-three patients with an occluded coronary artery and collateral circulation from a non-diseased vessel underwent two symptom-limited exercise 99mTc-MIBI, single-photon emission computed tomography (SPECT) myocardial scintigraphy experiments, which were preceded by an intravenous infusion of either aminophylline (5 mg/kg over 20 min) or saline solution in a randomized double-blind control procedure. The MIBI SPECT images were analysed by two experienced observers who were blinded to each other's data. RESULTS: All patients underwent cardiac catheterization. For 16 patients this was because of stable angina and the remaining eight were post-myocardial infarction patients with a positive exercise test. Aminophylline significantly increased the time to the onset of ischaemia in the 15 patients with a positive exercise test (mean +/- SD, 6.5 +/- 1.9 compared with 5.3 +/- 1.8 min, P < 0.005); and ischaemia occurred at higher rate-pressure product (230 +/- 68 compared with 195 +/- 68 HB x mmHg, P < 0.03). After aminophylline, exercise ST-segment depression was 1.1 +/- 0.5 mV, compared with 1.5 +/- 0.8 mV after placebo (P < 0.01). All patients had perfusion defects that resolved partially or completely in the rest images. The imaging score was significantly lower after aminophylline infusion than after placebo (9.7 +/- 9 compared with 12.1 +/- 10, P < 0.01). CONCLUSIONS: Aminophylline significantly delayed the time to onset of exercise-induced ischaemia and improved perfusion in zones supplied by collateral circulation. Aminophylline-like drugs may be useful in the treatment of selected patients with ischaemic heart disease.

Aminophylline↗
PubMed1996

Ala244Val is a common, probably ancient mutation causing factor VII deficiency in Moroccan and Iranian Jews.

We investigated the molecular basis for factor VII (FVII) deficiency in Israel and found that 13 patients were homozygous and 10 heterozygous for a C to T substitution at nucleotide 10648 of the FVII gene. This predicted an Ala244Val change and was associated with decreased FVII activity and antigen level. Of the 36 Ala244Val positive alleles, 20 were observed in patients of Moroccan origin, 10 in Iranian-Jewish patients and 6 in patients of other origins. A computer model of the serine protease domain of FVII suggested that the Ala244Val substitution may cause distortion of the entire protein structure. Intragenic polymorphic sites analyses disclosed a founder effect for the Moroccan and Iranian-Jewish patients. A survey of the Ala244Val mutation revealed an allele frequency of 1:42.5 in Moroccan Jews and 1:40 in Iranian Jews. As Moroccan Jews have been separated from Iranian Jews for more than two millennia, the data suggest that the Ala244Val mutation occurred in ancient times.

Alanine↗
PubMed1995

The striatal dopaminergic catalepsy mechanism is not necessary for the expression of pontine catalepsy produced by carbachol injections into the pontine reticular formation.

We have found previously that microinjections of carbachol into the pontine reticular formation (PRF) of rats induce an intense cataleptic state which is similar behaviorally with the catalepsy induced by systemic administration of neuroleptic drugs. In the experiments described in the present article we studied the possibility that the pontine carbachol catalepsy is generated via the intermediary of the dopaminergic cataleptogenic mechanism in the striatum. To this purpose we produced kainic acid lesions in the striatum and in the output stations of the striatal cataleptogenic mechanism-substantia nigra reticulata and the VM thalamic nucleus. Catalepsy was tested after systemic haloperidol (2 mg/kg) and pontine microinjections of carbachol (5 micrograms/1 microliter) before and after the kainic lesions. The cataleptogenic effect of carbachol injected in the pons was not attenuated by any of the three types of lesions. On the contrary, the cataleptogenic effect of haloperidol was greatly attenuated by the same lesions. These results suggest that the pontine catalepsy produced by microinjections of carbachol in PRF is generated independently of the dopaminergic cataleptogenic mechanism in basal ganglia.

Animals↗
PubMed1993

Characterization of the glycine-dependent redox-cycling activity in animal fluids and tissues using specific inhibitors and activators: evidence for presence of PQQ.

Pyrroloquinoline quinone, a redox cofactor first isolated from bacteria, efficiently catalyzes the nonenzymatic oxidation of glycine in the presence of nitroblue tetrazolium. We report that certain metallic cations and heterocyclic aromatic cations, like the N-methyl phenazonium cation and aryl-iodonium compounds, strongly and specifically inhibit this redoxcycling activity. The inhibition by metal cations is reversed by Tiron and that of the aromatic cations by Tiron and thyroxine. These inhibitors and activators affect authentic PQQ and the redox-activity of putative PQQ isolated from biological sources in a similar manner. This indicates that pyrroloquinoline quinone occurs naturally in animal tissues and fluids.

Animals↗
PubMed1992

Similarities between the akinesia induced by carbachol microinjections into the pontine reticular formation and neuroleptic catalepsy.

We reported previously that microinjections of carbachol directly into the pontine reticular formation of rats induced intense akinesia. In the present article we report results of tests for rigidity, righting, bracing and clinging which were conducted with the purpose to characterize behaviorally this type of akinesia. After injections of 5-15 micrograms/0.5 microliter of carbachol into the pontine reticular formation the rats were cataleptic, were not rigid when equilibrium was not challenged, had strong righting reflexes and strong bracing and clinging responses. This type of akinesia is different from the catatonia induced by systemic morphine (20 mg/kg IP), but similar to the catalepsy induced by systemic injections of haloperidol (5 mg/kg IP). It is thus suggested that the cataleptic state produced by topical carbachol in the pons is related to the dopaminergic mechanisms important for the cataleptic effect of the neuroleptic drugs.

Analysis of Variance↗
PubMed1990

Dopaminergic drugs influence the intensity of catalepsy induced by microinjections of carbachol into the reticular formation.

Carbachol microinjections into the mesencephalic and pontine reticular formation in rats induced intense and long-lasting catalepsy. Systemically administered haloperidol potentiated, while apomorphine and L-DOPA reduced the cataleptogenic effect of carbachol. These results indicate the existence of functional relations between the cholinergic cataleptogenic mechanism in the reticular formation and the dopaminergic system. They are interpreted in the light of known anatomical ascending and descending interconnections between the reticular formation and basal ganglia.

Animals↗