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Biomedical subjects

Luis García

Publications and source records attributed to Luis García.

14 recordsLinked to original sources
PubMed2006

[Brain and spinal cord magnetic resonance imaging in spastic paraparesis associated to human T-lymphotropic virus].

BACKGROUND: The spastic paraparesis associated to HTLV-1 causes degenerative pyramidal tract lesions of the spinal cord and affects cortical-nuclear connections in the brain. AIM: To report the findings of magnetic resonance imaging in patients with spastic paraparesis. MATERIAL AND METHODS: A magnetic resonance imaging of the brain and spinal cord was performed in 30 patients (24 females), mean age and evolution of 56 and 12 years respectively, with a clinical and virological diagnosis of tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM). RESULTS: No patient had abnormal signals in the spinal cord parenchyma. However, an atrophy of the dorsal segment was observed in 87% of patients. Patients with the highest degree of atrophy showed a higher degree of functional impairment. Eleven patients had spinal cord conus atrophy, associated to neurogenic bladder or impotency. In 80% of patients, hyperintense subcortical white matter images in DP, T2 and Flair, mostly bi frontal, were detected. In half of them, small rounded and isolated images were observed. In the other half, eight or more images, generally larger and occasionally confluent, were found. Ten of 12 patients with confluent brain lesions showed different degrees of cognitive impairment. No patient had lesions in the corpus callosus, periventricular white matter, pons, medulla oblongata or cerebellum. CONCLUSIONS: Most patients with tropical spastic paraparesis have alterations in brain or spinal cord magnetic resonance imaging. The magnetic resonance lesions are concordant with functional impairment. The characteristics of the imaging in TSP/HAM patients can be helpful in the differential diagnosis of patients with paraparesis.

Adult↗
PubMed2006

Comparative evaluation of the effects of unilateral lesion versus electrical stimulation of the globus pallidus internus in advanced Parkinson's disease.

OBJECTIVE: To perform a prospective analysis on the effects of unilateral lesion versus unilateral electrical stimulation (ES) of the globus pallidus internus (Gpi) in the treatment of bilateral Parkinson's disease (PD). MATERIALS AND METHODS: We studied 18 patients with stages III-V on the Hoehn and Yahr (H-Y) scale having prominent rigidity, bradykinesia and gait disturbances. Nine patients were treated with lesions and 9 patients with ES. Both groups were evaluated using the New York Parkinson's Disease Scale, the Unified Parkinson's Disease Rating Scale part III, and the H-Y scale and with specific items of tremor, rigidity and bradykinesia independently on each side. Both lesions and electrodes for ES were placed stereotactically in the Gpi as confirmed by postoperative magnetic resonance images. Significance of changes was evaluated with the Wilcoxon test after 3 and 6 months. Significance of intergroup differences was evaluated using the Mann-Whitney U test. RESULTS: Lesions and ES significantly decreased rigidity (p < 0.01) and bradykinesia (p < 0.005) in the contralateral extremities. ES significantly decreased tremor in the contralateral extremities (p < 0.01) and rigidity and bradykinesia ipsilaterally (p < 0.01) at 3 months. There were no significant intergroup differences. The H-Y scale score showed improvement in self-sufficiency. L-DOPA dose was decreased by 31%. CONCLUSIONS: ES was a safer procedure and more efficient in controlling PD symptoms. Unilateral lesions and ES may improve bilateral symptoms to the point of making patients self-sufficient.

Antiparkinson Agents↗
PubMed2006

In vivo bracket bond strength using two adhesive systems applied under wet and dry conditions.

The purpose of this study was to investigate, in vivo, the bond strength of two adhesive materials: a moisture insensitive primer (MIP)* and a one step self etching primer (SEP)*, both used with Transbond XT* on dry and wet enamel and an adhesion time of 10-15 minutes. First or second upper and/or lower bicuspids (n = 124), to be extracted for orthodontic reasons, were used. A comparison of the materials' behavior was conducted under four different situations: 1) MIP on enamel etched and dry; 2) MIP on a surface etched and wetted with patient's saliva; 3) SEP on a dry field, 4) SEP on a saliva-wet enamel. For statistical analysis, Dunn-Sidak's multiple comparison test was applied with a probability of less than 0.05 (before correction). Stainless steel brackets with mesh-backed pads were bonded to the teeth. Bond strength was tested with modified orthodontic pliers on which a strain-gage was fixed to measure handle deformation while debonding. Moisture insensitive primer tested on wet enamel showed the highest mean bond strength outcomes (8.98 MPa) compared to one step etching primer (5.81 MPa). Statistical difference between these groups was significant (p = 0.000). Standard deviation was lower for the one-step technique, under dry and wet conditions. Since the media bond strength of SEP proved sufficient for clinical purposes and its behavior tended to be more homogeneous, this was considered the best choice.

Adhesives↗
PubMed2005

The vaccine candidate Vibrio cholerae 638 is protective against cholera in healthy volunteers.

Vibrio cholerae 638 is a living candidate cholera vaccine strain attenuated by deletion of the CTXPhi prophage from C7258 (O1, El Tor Ogawa) and by insertion of the Clostridium thermocellum endoglucanase A gene into the hemagglutinin/protease coding sequence. This vaccine candidate was previously found to be well tolerated and immunogenic in volunteers. This article reports a randomized, double-blind, placebo-controlled trial conducted to test short-term protection conferred by 638 against subsequent V. cholerae infection and disease in volunteers in Cuba. A total of 45 subjects were enrolled and assigned to receive vaccine or placebo. The vaccine contained 10(9) CFU of freshly harvested 638 buffered with 1.3% NaHCO(3), while the placebo was buffer alone. After vaccine but not after placebo intake, 96% of volunteers had at least a fourfold increase in vibriocidal antibody titers, and 50% showed a doubling of at least the lipopolysaccharide-specific immunoglobulin A titers in serum. At 1 month after vaccination, five volunteers from the vaccine group and five from the placebo group underwent an exploratory challenge study with 10(9) CFU of DeltaCTXPhi attenuated mutant strain V. cholerae 81. Only two volunteers from the vaccine group shed strain 81 in their feces, but none of them experienced diarrhea; in the placebo group, all volunteers excreted the challenge strain, and three had reactogenic diarrhea. An additional 12 vaccinees and 9 placebo recipients underwent challenge with 7 x 10(5) CFU of virulent strain V. cholerae 3008 freshly harvested from a brain heart infusion agar plate and buffered with 1.3% NaHCO(3). Three volunteers (25%) from the vaccine group and all from the placebo group shed the challenge agent in their feces. None of the 12 vaccinees but 7 volunteers from the placebo group had diarrhea, and 2 of the latter exhibited severe cholera (>5,000 g of diarrheal stool). These results indicate that at 1 month after ingestion of a single oral dose (10(9) CFU) of strain 638, volunteers remained protected against cholera infection and disease provoked by the wild-type challenge agent V. cholerae 3008. We recommend that additional vaccine lots of 638 be prepared under good manufacturing practices for further evaluation.

Administration, Oral↗
PubMed2004

[Impact of metabolic syndrome in the control of blood pressure and dyslipemia].

BACKGROUND AND OBJECTIVE: The objective of the study was to assess the influence of metabolic syndrome (MS) in the control of blood pressure (BP) and dyslipemia. PATIENTS AND METHOD: A cross sectional study was performed with 1,320 (634 M and 686 F), 40.1 (13.3) years-old, BMI 29.8 (4.7) hypertensive non-diabetic patients. MS was diagnosed according to NCEP-ATP-III guidelines. Blood pressure control goal was BP < 140/90 mmHg. Coronary risk (CR) was calculated according to Framingham (low < 10%, intermediate 10-20% and high > 20% at 10 years). Goals of C-LDL levels were those of NCEP-ATP-III. RESULTS: 461 (35%) patients had MS and the remaining 859 became controls. Patients with MS had higher initial levels of hypertension and were receiving more antihypertensive drugs: 2.1 [1.3] vs. 1.7 [1.3]; p < 0.001), yet the average systolic and diastolic BP achieved and the degree of control was similar in both groups 53% vs. 52%; (p = ns). Patients with MS had higher CR at ten years than controls (10.7 [8.3] vs. 7.9 [6.8], p < 0.001) but achieved the C-LDL goals at fewer proportions than controls (57% vs. 74%; p < 0.001). In a regression analysis, patients with MS had 26% less probabilities of achieving both goals (p < 0.001). CONCLUSIONS: Hypertensive patients with MS have higher CR, and need more antihypertensive drugs to achieve the same BP goals. Yet it is more difficult for them to achieve LDL cholesterol goals. Patients with MS remain a target for cardiovascular prevention.

Anthropometry↗
PubMed2004

Mono- and binuclear cyclometallated palladium(II) complexes containing bridging (N,O-) and terminal (N-) imidate ligands: air stable, thermally robust and recyclable catalysts for cross-coupling processes.

Novel dinuclear cyclometallated palladium complexes [{Pd(mu-NCO)(C circumflex accent N)}(2)], containing asymmetric imidato -NCO- bridging units have been synthesised [C circumflex accent N = 7,8-benzoquinolyl; -NCO- = succinimidate (1c), phthalimidate (1a-3a) or maleimidate (3c)]. The reaction of these complexes, and the previously reported analogous imidate precursors containing a phenylazophenyl (1a-3a) or 2-pyridylphenyl (1b-3b) backbone, with tertiary phosphines provides novel mononuclear N-bonded imidate derivatives of the general formula [Pd(C circumflex accent N)(imidate)(L)][L = PPh(3), P(4-F-C(6)H(4))(3) or P(4-MeO-C(6)H(4))(3)]. The single crystal structures of [Pd(azb)(phthalimidate)(P(4-MeO-C(6)H(4))(3))](9a) and [Pd(bzq)(phthalimidate)(PPh(3))](7c) have been established. Dinuclear complexes (1a-3a, 1b-3b, 1c-3c) demonstrate outstanding thermal stability in the solid-state, as shown by thermoanalytical techniques. A marked influence of bridging imidate groups on the initial decomposition temperature is observed. The dinuclear and mononuclear derivatives are shown to be active catalysts/precatalysts for the Suzuki-Miyaura cross-coupling reactions of aryl bromides with aryl boronic acids, and the Sonogashira reactions of aryl halides with phenyl acetylene (in the presence and absence of Cu(I) salts). The conversions appear to be dependent, to some extent, on the type of imidate ligand, suggesting a role for these pseudohalides in the catalytic cycle in both cross-coupling processes. Lower catalyst loadings in 'copper-free' Sonogashira cross-couplings favour higher turnover frequencies. We have further determined that these catalysts may be recycled using a poly(ethylene oxide)(PEO)/methanol solvent medium in Suzuki-Miyaura cross-coupling. Once the reaction is complete, product extraction into a hexane/diethyl ether mixture (1 : 1, v/v) gives cross-coupled products in good yields (with purity > 95%). The polar phase can then be re-used several times without appreciable loss of catalytic activity.

Boronic Acids↗
PubMed2004

Pentacoordinate nickel(II) complexes double bridged by phosphate ester or phosphinate ligands: spectroscopic, structural, kinetic, and magnetic studies.

The bis(phosphatediester)-bridged complexes [[Ni([12]aneN(3))(mu-O(2)P(OR)(2))](2)](PF(6))(2) [[12]aneN(3)=Me(3)[12]aneN(3), 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene; R=Me (1), Bu (2), Ph (3), Ph-4-NO(2) (4); [12]aneN(3)=Me(4)[12]aneN(3), 2,4,4,9-tetramethyl-1,5,9-triazacyclododec-1-ene; R=Me (5), Bu (6), Ph (7), Ph-4-NO(2) (8)] were prepared by hydrolysis of the phosphate triester with the hydroxo complex [[Ni([12]aneN(3))(mu-OH)](2)](PF(6))(2) or by acid-base reaction of the dialkyl or diaryl phosphoric acid and the above hydroxo complex. The acid-base reaction was also used to synthesise the phosphinate-bridged complexes [[Ni([12]aneN(3))(mu-O(2)PR(2))](2)](PF(6))(2) [[12]aneN(3)=Me(3)[12]aneN(3), R=Me (9), Ph (10); [12]aneN(3)=Me(4)[12]aneN(3), R=Me (11), Ph (12)]. The molecular structures of complexes 2, 3 and 12 were established by single crystal X-ray diffraction studies. The eight-membered rings defined by the nickel atoms and the bridging ligands show distorted twist-boat, chair and boat-boat conformations in 2, 3 and 12, respectively. The experimental susceptibility data for compounds 2, 3 and 12 were fitted by least-squares methods to the analytical expression given by Ginsberg. The best fit was obtained with values of J=-0.11 cm(-1), D=-9.5 cm(-1) and g=2.20 for 2; J=-0.97 cm(-1), D=-9.3 cm(-1) and g=2.21 for 3; and J=-0.14 cm(-1), D=-11.9 cm(-1) and g=2.195 for 12. The magnetic-exchange pathways must involve the phosphate/phosphinate bridges, because these favour antiferromagnetic interactions. The observation of a higher exchange parameter for compound 3 is a consequence of a favourable disposition of the O-P-O bridges. The kinetics for the hydrolysis of TNP (tris(4-nitrophenyl)phosphate) with the dinuclear nickel(II) hydroxo complex [[Ni(Me(3)[12]aneN(3))(mu-OH)](2)](PF(6))(2) was studied by UV-visible spectroscopy. The proposed mechanism for TNP-promoted hydrolysis can be described as one-substrate/two-product, and can be fitted to a Michaelis-Menten equation.

Esters↗
PubMed2003

[Clinical use of statins and cholesterol goals in patients with several cardiovascular risk factors].

BACKGROUND AND OBJECTIVE: Our goal was to determine the number of patients who achieve low-density lipoprotein cholesterol (LDL-c) targets according to new guidelines. PATIENTS AND METHOD: Descriptive and transversal study of patients from a cardiovascular clinic. LDL-c was calculated and targets were established according the NCEP-ATP III. RESULTS: 1,811 patients (46% males, 54% females) were studied. 35% of these were high-risk patients (group 1: coronary risk > 20% at 10 years), 19% were intermediate-risk patients (group 2: coronary risk 10-20% at 10 years) and 46% were low-risk patients (group 3: coronary risk < 10% at 10 years). Overall, 58% of patients achieved target LDL-c levels, yet success rates were 26% among group 1 patients, 51% among group 2 patients, and 86% among group 3 patients (p = 0.001, for differences between groups). Statin treatment was significantly related to achieving target LDL-c levels in group 1 patients (OR = 1.7; 95% CI, 1.2-2.4; p = 0.007). In group 1.41% of patients had LDL-c levels > 130 mg/dl without receiving lipid-lowering drugs. CONCLUSIONS: Although an overall 58% patients achieve target LDL-C levels, only one of four high-risk patients have LDL-c levels < 100 mg/dl, and statin treatment is a determining factor to achieve this goal. These findings indicate that a more aggressive treatment with statins is needed in secondary prevention.

Aged↗
PubMed2003

Construction and characterisation of O139 cholera vaccine candidates.

The hemagglutinin/protease (HA/P) seems to be an attractive locus for the insertion of heterologous tags in live cholera vaccine strains. A deltaCTXphi spontaneous mutant derived from a pathogenic strain of O139 Vibrio cholerae was sequentially manipulated to obtain hapA Colon, two colons celA derivatives which were later improved in their environmental safety by means of a thyA mutation. All the strains here obtained showed similar phenotypes in traits known to be remarkable for live cholera vaccines irrespective of their motility phenotypes, although the hapA mutants had a 10-fold decrease in their colonisation capacity compared with their parental strains in the infant mouse cholera model. However, the subsequent thyA mutation did not affect their colonisation properties in the same model. These preliminary results pave the way for further clinical assays to confirm the possibilities of these vaccine prototypes as safe and effective tools for the prevention of O139 cholera.

Animals↗
PubMed2002

Bis(tetra-n-butylammonium) di-mu-chloro-bis[(tetramethyl buta-1,3-diene-1,2,3,4-tetracarboxylato-kappa(2)C(1),C(4))palladium].

The anionic complex in the title compound, (C(16)H(36)N)(2)[Pd(2)(C(12)H(12)O(8))(2)Cl(2)], lies on a centre of inversion, so that the [Pd(2)(mu-Cl)(2)] core is planar, which is the most frequent conformation found for complexes containing this moiety in the Cambridge Structural Database [October 2001 Release; Allen & Kennard (1993). Chem. Des. Autom. News, 8, 1, 31-37]. This dinuclear complex has a Pd...Pd distance of 3.5119 (4) A. The bite angle of the chelating ligand [79.79 (8) degrees] distorts the square-planar coordination around the metal atom.

Journal Article↗
PubMedDate not supplied

Diagnosis of sputum-scarce HIV-associated pulmonary tuberculosis in Lima, Peru.

Sputum induction, bronchoalveolar lavage, or gastric aspiration are often needed to produce adequate diagnostic respiratory samples from people with HIV in whom tuberculosis is suspected. Since these procedures are rarely appropriate in less-developed countries, we compared the performances of a simple string test and the gold-standard sputum induction. 160 HIV-positive adults under investigation for tuberculosis, and 52 asymptomatic HIV-positive control patients underwent the string test followed by sputum induction. The string test detected tuberculosis in 14 patients in whom this disease was suspected; sputum induction detected only eight of them (McNemar's test, p=0.03). These preliminary data suggest that the string test is safe and effective for retrieval of useful clinical specimens for diagnosis of pulmonary tuberculosis, and is at least as sensitive as sputum induction.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

[ULCERATIVE COLITIS: A 52 YEARS RETROSPECTIVE STUDY]

We present a retrospective study on 74 patients with inespecific chronic ulcerative colitis according to diagnostic criteria. The higher incidence was present in patients between 30 and 40 years old. The most frequent symptom was diarrhea (95%), abdominal pain (79%), rectal bleeding (87%), rectal tenesmus (50%), weight loss (36%), and fever (18%). In relation to the degree of severity, we found that 33,7% suffered mild symptoms, 46,6% had moderate symptoms, while 17,7% suffered severe symptoms. The endoscopic findings were: 93,2% friability, 90,5% hyperemia, and 84,4% granulatio. Mortality was of 6,7%. We concluded that this disease is rare in Peru. The related mortailty is low, symptoms are mostly moderate, and no association with cancer of colon was evidenced.

Journal Article↗