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Biomedical subjects

V Campos

Publications and source records attributed to V Campos.

At least 19 recordsLinked to original sources

[Early alterations of adrenergic cardiac function in Parkinson's disease].

INTRODUCTION: Myocardial sympathetic (adrenergic) function is significantly affected in patients with idiopathic Parkinson's disease (PD) as is deduced from the cardiac scintigraphy evaluation with 123I-metaiodobenzylguanidine (123I-MIBG). PATIENTS AND METHODS: In the present study, 60 patients with PD were studied compared to 17 normal subject without neurological disease. The clinical parameters evaluated were severity of the condition (measured by Hoehn and Yahr Scale), vegetative manifestations, development time and use and type of medication taken. Myocardial adrenergic function was analyzed by imaging with 123I-MIBG. Early (15 min) and delayed (4 h) images of the anterior view were obtained after injection of 123I-MIBG. Qualitative and semiquantitative 123I-MIBG uptake was quantified by calculating a heart-to-mediastinum (H/M) ratio. RESULTS: We found a significant decrease of H/M ratio in patients with PD as compared with controls (p < 0.01) independently of development time, severity of the condition, use of medication or vegetative manifestations. CONCLUSIONS: There is an important noradrenergic alteration in PD, that can be detected from early stages and does not exist in other parkinsonisms caused by a different pathogenic mechanism.

3-Iodobenzylguanidine↗

Chromate reduction in Serratia marcescens isolated from tannery effluent and potential application for bioremediation of chromate pollution.

Pollution of aquatic systems by heavy metals has resulted in increasing environmental concern because they cannot be biodegraded. One metal that gives reason for concern due to its toxicity is chromium. Cr(VI) and Cr(III) are the principal forms of chromium found in natural waters. A chromate-resistant strain of the bacterium S. marcescens was isolated from tannery effluent. The strain was able to reduce Cr(VI) to Cr(III), and about 80% of chromate was removed from the medium. The reduction seems to occur on the cell surface. Transmission electron microscopic examination of cells revealed that particles were deposited on the outside of bacterial cells. A stable biofilm was formed in less than 10 h, reaching around 1010 cfu attached per milligram of activated carbon. These findings demonstrate that immobilized S. marcescens might be used in industrial waste treatment processes.

Biodegradation, Environmental↗

Taxonomic study of extreme halophilic archaea isolated from the "Salar de Atacama", Chile.

A large number of halophilic bacteria were isolated in 1984-1992 from the Atacama Saltern (North of Chile). For this study 82 strains of extreme halophilic archaea were selected. The characterization was performed by using the phenotypic characters including morphological, physiological, biochemical, nutritional and antimicrobial susceptibility test. The results, together with those from reference strains, were subjected to numerical analysis, using the Simple Matching (S(SM)) coefficient and clustered by the unweighted pair group method of association (UPGMA). Fifteen phena were obtained at an 70% similarity level. The results obtained reveal a high diversity among the halophilic archaea isolated. Representative strains from the phena were chosen to determine their DNA base composition and the percentage of DNA-DNA similarity compared to reference strains. The 16S rRNA studies showed that some of these strains constitutes a new taxa of extreme halophilic archaea.

Archaea↗

[Total arterial myocardial revascularization with both mammary arteries without extracorporeal circulation].

INTRODUCTION: Tector has described the off-pump total arterial revascularization technique, using multiple anastomosis with both internal thoracic arteries. To reduce surgical morbid-mortality, we have proposed the use of this technique without extracorporeal circulation. PATIENTS AND METHODS: From April, 1998 the off-pump < > technique was performed in 92 patients, 74 male (80%) and 18 female (20%), with a mean age of 64.9+/-8.1 years (42-78). Preoperative angiography demonstrated triple-vessel disease in 58 (63%) patients, and left main disease was present in 19 (20.5%) patients. Forty patients (43.5%) showed unstable angina, 24 patients (26%) significant peripheral vascular disease, and 26 (28%) diabetes mellitus. Both internal thoracic arteries were harvested using the skeletonization technique and were used like a < > graft. The flow in the graft was measured using a flowmeter, and in 24 (26%) patients by angiographic study. RESULTS: A total of 274 distal anastomoses were performed, 122 (44.6%) in the lateral or inferior wall, and 69 (25.2%) were sequential, with an average of 2.98 bypass/patient. In 59.8% of the patients a triple bypass was performed, 22% double bypass, 17% cuadruple bypass and 1 patient a quintuple bypass. During the initial six hours 64.9% of patients were extubated. Only one patient (1.1%) needed intraaortic ballon pumping and 3 (3.2%) inotropics during the postoperative course. Hospital mortality was 3 (3.2%) patients. Reoperation for bleeding was needed in just one patient (1.1%), and 78.3% of patients were not transfused. Mediastinitis occurred in 3 patients (3.2%). Postoperative stroke was not observed. At 7.7+/-2.8 months of mean follow-up all patients were free of symptoms and the global patency rate of 94%. CONCLUSIONS: Off-pump Tector technique appears to be safe, offering a complete arterial revascularization and showing a reduction of surgical morbidity.

Adult↗

Co-occurrence of non-toxic (cyanopeptolin) and toxic (microcystin) peptides in a bloom of Microcystis sp. from a Chilean lake.

A cyanobacterial bloom occurring in 1998 in lake Tres Pascualas (Concepción/Chile) was found to be dominated by Microcystis sp. The bloom contained both non-toxic (cyanopeptolin-type) and hepatotoxic (microcystin-type) peptides. Cyanopeptolin structure of the non-toxic peptides (called cyanopeptolin VW-1 and VW-2, respectively) was revealed by matrix assisted laser desorption ionization mass spectrometry (MALDI-TOF-MS) of whole cells, showing dominant molecular ions at m/z = 975 and m/z 995, respectively. On post source decay (PSD), both cyanopeptolins showed fragments deriving from Ahp-Phe-MTyr (3-amino-6-hydroxy-2-piperidone), the characteristic partial structure of cyanopeptolins. The amounts of each of the two cyanopeptolins could only roughly be estimated to be >0.1% of bloom material dry weight. In addition the blooms contained microcystins (20 microg/g bloom dry weight as determined by RP-HPLC, 13 microg/g according to ELISA determination). MALDI-TOF-MS revealed several structural variants of microcystin: MCYST-RR (microcystin with Arg and Arg, indicated by m/z 1,038 and confirmed by PSD revealing a m/z = 135 fragment deriving from the Adda side chain, MCYST-FR (microcystin with Phe and Arg, indicated by m/z = 1,015). The presence of [Asp(3)]-MCYST-LR (microcystin with Leu and Arg, Asp non-methylated, indicated by m/z 981), and [Asp(3)]-MCYST-YR (microcystin with Tyr and Arg, Asp non-methylated, indicated by m/z 1,031) were likely. The relative amounts of the peptides varied between February, April, and May. Whole cell extracts from the bloom material revealed specific enzyme inhibitory activities. The serin-proteases trypsin, plasmin, elastase were inhibited, assumable due to the cyanopeptolins found. Elastase and the cysteine-protease papain were not inhibited, inhibitions of protein kinase and glutathione S-transferase (GST) were low. Strong inhibition was observed with protein-phosphatase-1, likely due to the microcystins present in the samples.

Bacterial Toxins↗

Hereditary gingival fibromatosis: review of the literature and a case report.

Hereditary gingival fibromatosis is a proliferative fibrous lesion of the gingival tissue that causes esthetic and functional problems. Both genetically and pharmacologically induced forms of gingival fibromatosis exist. This paper reports a case of severe generalized hereditary gingival fibromatosis in a 5-year-old girl. Treatment consisted of surgical removal of the hyperplastic fibrous tissue in a series of conventional gingivectomies. Postoperative examination 36 months after the final procedure revealed no signs of recurrence.

Child, Preschool↗

Microcystin in cyanobacterial blooms in a Chilean lake.

Cyanobacterial blooms dominated by Microcystis sp. occurred in lake Rocuant ("marisma", near Concepción/Chile) in February 1995 and 1996. In the bloom samples collected in both years the hepatotoxin microcystin was detected by RP-HPLC in both samples and in the sample of 1995 also by a toxicity assay using primary rat hepatocytes. In the bloom of 1995, the microcystin content of the dry bloom biomass was determined to be 130 micrograms/g on the basis of the RP-HPLC peak area and 800 micrograms/g on the basis of the rat hepatotoxicity assay, respectively. In the bloom of 1996, RP-HPLC analysis revealed a microcystin content of 8.13 micrograms/g bloom material dry weight. In this year no hepatotoxicity was measured using a concentration range up to 0.8 mg (d. w.) of bloom material per ml in the rat hepatotoxicity assay. This is the first report on the detection of microcystins in Chilean water bodies.

Animals↗

Is the femoral cannulation for minimally invasive aortic valve replacement necessary?

INTRODUCTION: Minimally invasive cardiac surgery through a small transverse sternotomy is a new promising technique that can be considered an alternative in most cases to aortic valve replacement thus reducing surgical trauma and subsequent time of hospitalization. The need to avoid the risks associated with femoro-femoral bypass has lead to the interest in aortic valve replacement (AVR) operations without femoral vessels cannulation. We want to emphasize a few important points of our technique, which differs somewhat from the one applied by Cosgrove and associates. OBJECTIVE: This study details the approach to the minimally invasive AVR as first described by. Cosgrove et al. without standard femoral cannulation and points out our preliminary clinical experience. PATIENTS AND METHODS: From October 1996 to May 1997 we have operated on 25 patients using minimally invasive AVR (MI-AVR) In 23 cases, access through transverse sternotomy as described by Cosgrove et al., was performed. In two additional cases the chest is opened via a mini-median sternotomy with an 'L'-shape extending from the sternal notch to the superior edge of the third interspace. Twenty-three patients underwent AVR through transverse sternotomy. The male/female ratio was 13:10. The mean age was 67 years (range 45-78 years). Seventy-four percent of the patients were over 65. Predominantly, in 43% of cases aortic valve stenosis and in 25% of cases aortic valve regurgitation isolated is presented. In 19 cases, a 10-cm transverse incision is performed over the second interspace. Likewise, in four cases over the third interspace according to the thorax morphology and length of the ascending aorta assessed by chest X-ray films. By convention, cannulation of the ascending aorta and right atrial appendage was performed as usual. In contrast, in one patient (5.5%), cannulation was placed in the superior vena cava and right common femoral vein into the inferior vena cava. In the present series, 15 mechanical prostheses and eight bioprostheses whose used sizes were 19, 21,23, and 25 mm in diameter were placed in four, nine, nine, and one of the cases, respectively. All patients underwent AVR electively and a transesophageal echocardiography probe is made. RESULTS: During surgery, conversion to median sternotomy was not required in any patient. Mean aortic cross-clamp time was 68 min (range 38-90 min). Mean total bypass time was 87 min (range 50-120 min). Mean postoperative bleeding was 434 ml. (range 200-850 ml). Perioperative blood transfusion was required in 17% of the patients. Mean mechanical ventilation time was 7.3 h (range 3-24 h), with a mean ICU stay of 18 h. Mean postoperative hospital stay was 4.5 days (range 3-10 days). In all cases, transthoracic and transesophageal echocardiography were performed postoperatively Prosthetic valve dysfunction was not observed. On the other hand, just one patient (4%) died 5 days after operation due to sudden cardiac death. Further, in two patients (8%), during follow-up, pericardial effusion is detected. In one case, cardiac tamponade with hemodynamic instability required a pericardial window procedure. In addition, in two patients (8%), non-infectious sternal dehiscence required reinforced sternal closure. CONCLUSIONS: Minimally invasive AVR surgery without femoral vessel cannulation is a safe procedure with less surgical aggression. After a learning curve, benefits on fast-track programs will be accomplished.

Aged↗

[Coronary surgery without extracorporeal circulation: 5-year experience].

INTRODUCTION: Coronary surgery without extracorporeal circulation is now an accepted technique of myocardial revascularization. A progressive increase in operations has recently been observed. OBJECTIVE: We report our total experience with this technique in a consecutive series of patients operated on since 1991. This series is compared with other series of patients who underwent coronary surgery using cardiopulmonary bypass. PATIENTS AND METHODS: From December 1991 to July 1996, thirty patients underwent myocardial revascularization without cardiopulmonary bypass through median sternotomy at our institution. This group was retrospectively compared with 22 patients who received isolated coronary artery bypass grafting with cardiopulmonary bypass (excluding reoperations) during the same period of time. RESULTS: There were two hospital deaths and one case of myocardial infarction during the early postoperative period which required urgent reintervention. There were two variables showing a statistically significant difference between the groups with and without cardiopulmonary bypass. Incidence of non-fatal preoperative myocardial infarction increased (53% vs 23%), whereas minor mechanical ventilation time was reported (7 +/- 5 vs 14 +/- 9 h) in the group without cardiopulmonary bypass. Follow-up (1 to 55 months after operation, mean 29 months) was completed. There were no cardiac-related deaths. No return of angina nor any new myocardial infarctions were recorded. New myocardial revascularizations were not necessary. CONCLUSIONS: Myocardial revascularization without extracorporeal circulation obtained good results that were similar to conventional procedures and were cost-effective.

Adult↗

Comparison between the polypeptide profile of halophilic bacteria and salt tolerant plants.

Changes in the polypeptide profile induced by salt stress in halotolerant and halophilic bacteria, isolated from the Atacama desert (northern Chile), were compared with those in the cotyledons of Prosopis chilensis (Leguminoseae) seedlings, a salt tolerant plant. SDS-PAGE analyses show the presence of four predominant polypeptides, with molecular weights around 78, 70, 60 and 44 kDa respectively, both in bacteria and in cotyledons from P. chilensis seedlings raised under salt stress conditions. Moreover, the 60 and 44 kDa polypeptides seem to be salt responsive, since their concentration increases with increasing NaCl in the growth medium. Our results suggest a common mechanism for salt tolerance in prokaryotes and in eukaryotes.

Adaptation, Physiological↗

Production of extracellular xylanases by Penicillium janthinellum. Effect of selected growth conditions.

Xylanase production by Penicillium janthinellum using 10-100 mM of 2,2-dimethylsuccinate (DMS) buffer, in a range of pH 4.5-6.0 was studied. The enzyme activity was enhanced using oat xylan as the carbon source. Under these conditions a culture produced 1.14 mumol/min (11.4 U/mL or 84.4 U/mg) of beta-xylanase after 5 d of growth in a 10-mM buffer solution at pH 4.5. Protease was absent in the DMS buffer except when 100 mM phosphate buffer at pH 6.0 was used (4 U/mL). beta-Xylosidase was only found at a pH of 4.5 in all the buffer concentrations. At a 50 mM DMS buffer concentration at pH 4.5 beta-xylanases were induced by both oat and birch xylans, having a greater effect with oat spelt xylans. Electrophoretic analyses showed that the birchwood xylan induction exhibited different proteins profiles. No beta-xylosidase or beta-glucosidase was induced until d 5. The beta-xylanases were rapidly inactivated at 50 degrees C, however, birch xylanase appeared to be more stable than oat xylanase. Using oat xylan as an inductor, the beta-xylosidase and beta-glucosidase were 85 and 91 U/L, respectively, on d 7. The xylanase produced by induction from sugar cane bagasse hydrolyzate was used for pulp biobleaching. A 20% decrease on the Kappa value in Kraft pulp using the culture extract was obtained. These selective growth conditions led us to modulate the xylanase production for pulp delignification.

Avena↗

Bacterial chemistry. VI. Biological activities and cytotoxicity of 1,3-dihydro-2H-indol-2-one derivatives.

The biosynthetic pigment from Chromobacterium violaceum BB-78, 1,3-dihydro-2H-indol-2-one and its derivatives exhibit biological activities such as antimicrobial action, low hemolytic effects on red blood cells and in vitro trypanocide activity. A relatively high cytotoxicity on V-79 hamster fibroblast cells of the biosynthetic pigment was found, although with the methylol derivative the toxicity was almost eliminated. The methylol derivative exhibited similar toxicity as Nifurtimox, a known, commercial trypanocide compound.

Animals↗

Numerical taxonomy of moderately halophilic gram-positive cocci isolated from the Salar de Atacama (Chile).

A taxonomic study has been carried out on 22 strains of moderately halophilic motile cocci isolated from the Salar de Atacama (Chile). The 112 phenotypic tests were analyzed by numerical taxonomy using SSM coefficient and the unweighted pair group method of association (UPGMA). At the 67% similarity level, two phenons were obtained: phenon A included 11 strains and phenon B, 11 strains too, whereas the six reference strains did not cluster within these two phenons. These results suggest that moderately halophilic cocci with different phenotypic characteristics from previously described species can be isolated from the hypersaline habitat Salar de Atacama.

Chile↗

Inhibitory effect of GABA on cerebrovascular sympathetic neurotransmission.

The possibility that gamma-aminobutyric acid (GABA) could modulate sympathetic neurotransmission in the cerebrovascular bed of the goat has been investigated by means of 3 experimental approaches: measurement of cerebral blood flow in the anesthetized animal, recording of isometric tension in isolated cerebral arteries, and measurement of tritium efflux from cerebral arteries preloaded with [3H]noradrenaline. Electrical stimulation of cervical sympathetic nerve produced reductions in cerebral blood flow which were significantly diminished during continuous infusion of GABA (20-40 micrograms/min) into the internal maxillary artery. Picrotoxin (3 mg) did not change the inhibitory effect of GABA. Exogenously administered noradrenaline (1-9 micrograms) and tyramine (50-500 micrograms) reduced cerebral blood flow as well, but this effect was unchanged by GABA infusion. Transmural electrical stimulation elicited frequency-dependent contractile responses in isolated cerebral arteries which were significantly blocked when GABA was present, at a dose (10(-4) M) which did not modify the contractile response to exogenous noradrenaline (10(-8)-10(-4) M). Moreover, GABA (10(-5)-10(-4) M) inhibited transmural electrical stimulation-evoked tritium efflux from arteries preloaded with [3H]noradrenaline. These results show that GABA inhibits adrenergic neurotransmission in cerebral arteries by a mechanism involving inhibition of transmitter release. Probably, specific presynaptic GABA-B receptors mediate this inhibitory effect.

Adrenergic Fibers↗

Bacterial chemistry-III: preliminary studies on trypanosomal activities of Chromobacterium violaceum products.

It has been found that the pigment-I from Chromobacterium violaceum, 3-[1,2-dihydro5-(5-hydroxy-1H-indol-3-yl)-2-oxo-3H-pyrrol-3-yli diene] 1,3-dihydro-2H-indol-2-one, has trypanocide activity. The formylated derivatives, pigment-III, immobilized 100% of the Trypanosoma cruzi at a level of 46 microM after 48 h of interaction with a total growth inhibition in the same period. Pigment-I exhibited low toxicity and a DNA synthesis inhibition similar to that of Nifurtimox, a known trypanocide compound.

Animals↗

P1-purinoceptors in the cerebrovascular bed of the goat in vivo.

The possible existence and function of specific P1-purinoceptors in the cerebrovascular bed of the unanesthetized goat have been investigated. Blood flow to one cerebral hemisphere (cerebral blood flow) was measured by means of an electromagnetic flow probe previously implanted around the ipsilateral internal maxillary artery. The injection of adenosine, AMP, ADP and ATP (3-30 micrograms) directly into the internal maxillary artery increased cerebral blood flow and decreased cerebrovascular resistance in a dose-dependent manner. Continuous infusion of 8-phenyltheophylline (8-PT), 100 micrograms/min, into the internal maxillary artery did not alter the resting cerebral blood flow or the cerebrovascular resistance, but significantly inhibited the cerebral vasodilation induced by adenosine, AMP, ADP and, to a lesser degree, ATP. The acetylcholine- and histamine-induced cerebral vasodilation was unaffected by 8-PT. These results indicate that adenosine, AMP, ADP and, at least in part, ATP increase cerebral blood flow by acting on specific P1-purinoceptors located in the cerebrovascular wall. These P1-purinoceptors do not appear to be tonically activated under physiological conditions.

Adenosine↗