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Biomedical subjects

M Cortés

Publications and source records attributed to M Cortés.

At least 19 recordsLinked to original sources
PubMed2003

The effects of superior ovarian nerve sectioning on ovulation in the guinea pig.

The effects on spontaneous ovulation associated with the unilateral or bilateral sectioning of the superior ovarian nerves (SON) were analyzed in guinea pigs at different time intervals of the estrous cycle. Day 1 of the estrous cycle was defined as the day when the animal presents complete loss of the vaginal membrane (open vagina). Subsequent phases of the cycle were determined by counting the days after Day 1. All animals were autopsied on the fifth day of the estrous cycle after surgery. Sectioning the right, left, or both SONs on day 5 (early luteal phase) resulted in a significant increase in the number of fresh corpora lutea. Ovulation increased significantly when the left SON (L-SON) was sectioned during late follicular phase (day 1) and medium luteal phase (day 8). When surgery was performed on days 1 or 8, neither sectioning the right SON (R-SON) nor sectioning the SON bilaterally had an apparent effect on ovulation rates. Similarly, ovulation rates were not affected when unilateral (right or left) or bilateral sectioning of the SON was performed during late luteal phase two (day 12). Unilateral or bilateral sectioning of the SON performed during the early luteal phase (day 5) was associated with a significant decrease in uterine weight. A comparable effect was observed when the L-SON was sectioned during late follicular phase (day 1), or medium luteal phase (day 8). No effects on uterine weight were observed when unilateral or bilateral sectioning of the SON was performed during late luteal phase. Our results suggest that in the guinea pig the SON modulates ovulation, and that the degree of modulation varies along the estrous cycle. The strongest influence of the SONs on ovulation occurs during early luteal phase, and decrease thereafter, being absent by late luteal phase. In addition, sectioning the left or the right SON caused different responses by the ovaries of adult guinea pigs. This paper discusses the mechanisms by which ovulation increased when the SON was surgically cut.

Animals↗
PubMed2002

[Isotopic renal study in diabetic nephropathy].

UNLABELLED: This study aimed to evaluate the prognostic value of the kidney split function (KSF), the effective renal plasma flow (ERPF) and glomerular filtration rate (GF) in the evolution of diabetic nephropathy. MATERIAL AND METHODS: 125 patients (IDDM:10, NIDDM:115), including 62 men, ages 18-84 years, were studied. In all cases GF (Cr 51 EDTA), ERPF (131I-hippuran), kidney split function (obtained from the 99mTc-MAG3 renogram) and basal serum creatinine (SC) were evaluated at the beginning of the study and patients were clinically followed up for 5 years by SC. Ultrasound and/or intravenous digital angiography were performed in 120 patients. RESULTS: In patients with decreased ERPF (76 patients) the SC increased progresively during the 5 years, in both those with elevated PC (N = 54) as well as in those with normal baseline SC (n = 22). In patients with normal ERPF the SC did not change significantly during the study. An asymethric split function (KSF < 40% in one kidney) was found in the renogram of 42 patients; in 32 of them the ERPF was decreased. Of these, ulttrasonography was normal in 9, and vascular and/or obstructive pathology was demonstrated by ultrasonography or digital angiography in only 6 patients. CONCLUSION: The ERPF becomes altered earlier than serum creatinine in patients with diabetic nephropaty. ERPF and split function calculation, and FG seems to have higher prognostic value than ultrasounds in the management of diabetic nephropathy. Radionuclides seems to be an accurate test than the ultrasonography to detect renal function abnormalities in patients with diabetic and thus can be an examination of choice in these patients.

Adolescent↗
PubMed2001

Prospective randomized trial comparing conventional laparoscopic colectomy with hand-assisted laparoscopic colectomy: applicability, immediate clinical outcome, inflammatory response, and cost.

BACKGROUND: Hand-assisted laparoscopic surgery (HALS) represents a useful alternative to conventional laparoscopic surgery (LS). Its potential advantages--(a quicker, safer procedure and less need to convert to open surgery) are due to the recovery of tactile feedback. However, HALS requires the performance of a mini-laparotomy when surgery commences, and the wound is stretched and compressed throughout the procedure. In addition, it is associated with a more intense manipulation of the intraabdominal viscera. All of these factors increase the surgical trauma, it is not known whether HALS maintains the minimally invasive characteristics of conventional LS. Therefore, we set out to study the applicability, immediate clinical outcome, inflammatory response, and cost of HALS compared with conventional LS using colectomy as a model. METHODS: We performed a prospective randomized trial comparing laparoscopic-assisted colectomy with HAL colectomy. The aims of the study were to assess (a) perioperative features, including time, advantages, and conversion; (b) the patient's immediate clinical response, including recovery of bowel sounds, refeeding time, postoperative pain, local and general morbidity, and hospital stay; (c) the effect on the inflammatory response, using interleukin-6 (ILG) and C-reactive protein (CRP) measurements; (d) oncological issues, including intraoperative cytology and features of the specimen; and (d) the relative costs of the two procedures. RESULTS: A total of 54 patients were enrolled in the study, 27 laparoscopic and 27 HALS. The operative times were similar, but HALS was associated with a far lower conversion rate--7% vs 23%. Immediate clinical outcomes, oncological features, and costs were similar for the two procedures, but HALS was associated with a significantly greater increase in IL6 and CRP than the conventional laparoscopic procedure. CONCLUSION: This comparative study shows that HALS simplifies difficult intraoperative situations, reducing the need for conversion. Although it is a more aggressive procedure, HALS preserves the features of a minimally invasive approach, maintains all of the oncological features of conventional laparoscopic surgery, and does not increase the cost. HALS should therefore be considered as a useful adjunct when difficult situations arise during conventional laparoscopic colectomy.

Aged↗
PubMed2001

Gamma probe sentinel node localization and biopsy in breast cancer patients treated with a neoadjuvant chemotherapy scheme.

The aim of this study was to analyse the accuracy of scintigraphic and gamma probe sentinel node (SN) localization in breast cancer patients who have been submitted to neoadjuvant chemotherapy (NC). Seventy-six patients with single breast cancer were included in the study, and were classified into two groups. Group 1 consisted of 40 women who had received NC, and Group 2 consisted of 36 women who did not receive NC. All patients received 111 MBq (3 mCi) of 99Tcm-nanocolloid in 3 ml, by peritumoural injection. Anterior and lateral thoracic scans were obtained 2 h post-injection. The following day (18-24 h post-injection) the patients underwent surgery and sentinel nodes were localized by using a gamma probe. Complete axillary lymph node dissection was performed in all patients. Histological analysis included haematoxylin-eosin in all cases and immunohistochemistry in 10 cases. In Group 1, SNs were localized in 36/40 patients, histological analysis was performed in 34 and there were four false negatives (22%). In Group 2, SNs were localized in 32/36 patients, histological analysis was performed in 29 and there were two false negatives (9%). Predictive negative values were 78% and 90% in Groups 1 and 2, respectively. In summary, sentinel node localization in breast cancer patients submitted to previous neoadjuvant chemotherapy is less accurate than in patients who do not receive this therapy. The procedure is not sufficiently accurate to localize the sentinel node, thus it cannot be recommended in these patients.

Adult↗
PubMed2001

[Bone metastasis from gastrinoma without hepatic involvement. Utility of the scintigraphy with 111 In-pentetreotide].

The case of a 54 year old patient suffering from gastrinoma (within a type I multiple endocrine neoplasm) is presented. In 1990, she underwent a surgical resection. Eight years later, she suffered from a pain in the left thigh. The 99mTc-MDP bone scintigraphy showed bone metastasis. The CT scan did not show any hepatic involvement and the scintigraphy with 111In-Pentetreotide verified bone metastasis of a neuroendocrine tumor as a single expression of the recidive. In this case, the utility of the scintigraphy with octreotide to facilitate the localization and extent of the neuroendocrine tumors is demonstrated.

Adrenalectomy↗
PubMed2000

Sensitivity of trypanosomatid protozoa to DFMO and metabolic turnover of ornithine decarboxylase.

alpha-Difluoromethylornithine (DFMO), the specific and irreversible inhibitor of ornithine decarboxylase (ODC), was able to induce the arrest of proliferation in Leishmania mexicana and ODC-transformed Trypanosoma cruzi cultures grown in a semi-defined medium essentially free of polyamines. Conversely, Crithidia fasciculata and Phytomonas 274 were not affected by the inhibitor. The drug-resistance of Crithidia and Phytomonas was neither caused by an impairment of DFMO uptake nor by a decrease of the enzyme affinity for the inhibitor. We were also able to rule out the possibility of ODC overexpression in the drug-tolerant parasites. The measurements of ODC metabolic turnover indicated that the enzymes from Crithidia and Phytomonas have a short half-life of 20-40 min, while ODC from Leishmania and transgenic Trypanosoma cruzi are rather stable with a half-life longer than 6 hours. Analyses of polyamine internal pools under different growth conditions have shown that DFMO was able to markedly decrease the levels of putrescine and spermidine in all parasites, but the depletion of spermidine was higher in trypanosomatids containing an ODC with slow turnover. Our results suggest that in these parasites cultivated in the presence of the drug, spermidine might decrease below critical levels needed to maintain trypanothione concentrations or other conditions essential for normal proliferation.

Animals↗
PubMed2000

Catecholamines-evoked cytosolic Ca2+ rise in endothelial cells from bovine adrenal medulla.

The effects of catecholamines on intracellular Ca2+ concentrations ([Ca2+]i) in single acutely dissociated bovine adrenal medulla endothelial cells (BAMECs) were measured using the intracellular fluorescent probe Fluo-3 AM. 100 microm epinephrine or norepinephrine induced a biphasic [Ca2+]i rise with an initial peak followed by a delayed phase. 10 microm phenylephrine (alpha1-adrenergic agonist) caused a [Ca2+]i rise similar to that evoked by catecholamines. The increase in [Ca2+]i induced by 10 microm phenylephrine was reverted by 10 microm phenoxybenzamine (alpha-adrenergic antagonist). Neither isoproterenol (beta-adrenergic agonist) nor clonidine (alpha2-adrenergic agonist) induced [Ca2+]i rise. The initial peak was insensitive to zero external Ca2+ and it was abolished after Ca2+ internal storages were emptied by 10 mM caffeine. The delayed phase was reduced to near zero by external Ca2+ removal. These results indicate that BAMECs possess alpha1-adrenergic receptors associated to both the release of caffeine-sensitive intracellular Ca2+ stores and the entry of extracellular Ca2+. We suggest that chromaffin cell secretion may activate BAMECs in vivo through an increase in [Ca2+]i which could induce the secretion of vasoactive factors allowing a rapid entry of hormones into the circulation.

Adrenal Medulla↗
PubMed1999

Microbial hydroxylation of natural drimenic lactones.

Incubation of confertifolin and isodrimenin with Mucor plumbeus, Aspergillus niger or Rhizopus arrhizus gave in good yields the corresponding 3 beta-hydroxy derivatives. From isodrimenin, the known natural 7 alpha-hydroxy derivative (futronolide) was also obtained and its structure was definitely established by X-ray crystallographic study of its acetate derivative.

Crystallography, X-Ray↗
PubMed1999

Beta 2-microglobulin and immunoglobulins are more useful markers of disease progression in HIV than neopterin and adenosine deaminase.

Reference change values of six biochemical quantities (beta 2-microglobulin, neopterin, adenosine deaminase and immunoglobulins IgA, IgG and IgM) have been established in asymptomatic human immunodeficiency virus (HIV)-infected patients following the method described by Harris and Yasaka in 1983. Patients included in the evaluation were classified as A1, A2 or A3 according to the classification of the Centers for Disease Control (CDC) (January 1993). All patients were followed-up quarterly, with a minimum of four samples each available for statistical analysis. The main objective of this paper was to study whether differences found to be greater than calculated reference change values could predict clinical or immunological worsening in patients' status. Retrospective analysis was made in asymptomatic patients (n = 256) included in an HIV infection protocol carried out in our hospital. Of these patients, 179 showed clinical or immunological worsening during the study period and 77 maintained their clinical and immunological status. Changes in beta 2-microglobulin showed the greatest sensitivity to detect clinical or immunological worsening (43.0%), whereas changes in adenosine deaminase showed the lowest (21.8%). Clinical or immunological worsening in 169 of the 179 patients was detected by one of the six biochemical quantities evaluated. Ten patients showed clinical or immunological worsening, although differences between measurements were lower than the reference change values calculated. Of 77 patients whose clinical state did not deteriorate, there was a change in biochemical analytes greater than the reference value calculated in 29 patients (a period of 12 months had elapsed since detection). In 48 patients, no increases greater than calculated reference change values were detected. The sensitivity obtained using the six analytes was 94.4% and the specificity was 62.3%.

Adenosine Deaminase↗
PubMed1999

Patients with thrombocytosis have normal or slightly elevated thrombopoietin levels.

BACKGROUND AND OBJECTIVE: The distinction between clonal and reactive thrombocytoses is a frequent problem and implies different therapeutic options. As thrombopoietin (TPO) is the main regulator of megakaryocytopoiesis and thrombopoiesis, we measured TPO levels in patients with thrombocytosis in an attempt to understand the regulation and potential utility of distinguishing thrombocytoses. DESIGN AND METHODS: Serum TPO levels, platelet counts, mean platelet volume, hemoglobin, erythrocyte sedimentation rate and age were evaluated in 25 patients with clonal thrombocytosis (15 with essential thrombocythemia, 6 with polycythemia vera and 4 with chronic myeloid leukemia) and in 50 patients with reactive thrombocytosis distributed in three groups: 1) patients in post-surgical states; 2) patients with solid tumors; and 3) patients with inflammatory diseases. RESULTS: TPO levels were slightly increased in patients with clonal (135+/-50 pg/mL) and reactive (147+/-58 pg/mL) thrombocytosis compared with controls (121+/-58 pg/mL). Analyzing the different groups, patients with essential thrombocythemia had the lowest TPO levels (120+/-28 pg/mL) and patients with solid tumors the highest levels (162+/-59 pg/mL). Patients with clonal thrombocytosis were older, had higher platelet counts, mean platelet volume and hemoglobin, and lower erythrocyte sedimentation rate than patients with reactive thrombocytosis. INTERPRETATION AND CONCLUSIONS: Minor differences were observed in TPO levels between patients with primary and secondary thrombocytoses. Erythrocyte sedimentation rate, but not TPO levels, may be a useful tool for discriminating both types of thrombocytoses.

Adolescent↗
PubMed1998

The predictive value of several markers in the progression to acquired immunodeficiency syndrome.

Serum beta 2-microglobulin, neopterin, immunoglobulins A, G and M, adenosine deaminase and CD4+ lymphocyte count were evaluated as predictors of progression of HIV-1 infection to AIDS. A population of HIV-1 seropositive, initially asymptomatic men (n = 213) and women (n = 101) was followed up quarterly. We estimated the AIDS-free time using the actuarial method (median survival time 47.2 months). Cox proportional hazard analysis revealed that all markers studied were significant (p < 0.05) in relation to progression to AIDS. The best markers for predicting progression to AIDS were, in descending order, CD4+ lymphocyte count, beta 2-microglobulin, IgA, neopterin, IgG, IgM and adenosine deaminase. On stratifying population into four groups (divided at percentiles 25, 50 and 75--from group 1, with values nearest to reference ranges, to group 4, with most abnormal values) we observed statistically significant differences (p < 0.05) for all markers except for adenosine deaminase. The relative risk from the Cox proportional hazards model were used to quantify the effects of the best markers and compared to the risk obtained in group 1. CD4+ lymphocyte count was the best predictor of progression to AIDS. When considering beta 2-microglobulin and CD4+ together, the relative risk in the group with lowest CD4+ cell count (group 4) ranged from 25.6% (with lower beta 2-microglobulin values) to 41.1% (with higher beta 2-microglobulin values). Similar results were obtained when considering neopterin and CD4+ together. The addition of beta 2-microglobulin or neopterin values to CD4+ lymphocyte count improved the predictive value of CD4+ lymphocyte count.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Protein degradation in red cells exposed to 2,2'-azo-bis(2-amidinopropane) derived radicals.

Extensive proteolysis is observed when red blood cells are exposed to free radicals produced in the thermolysis of 2,2'-azo-bis(2-amidinopropane). It is evaluated that nearly one amino terminal group is produced by each free radical introduced into the system. These groups are considered to arise mainly from band 3 fragmentation due to the action of red cell proteinases. Protein fragmentation takes place prior to significant hemolysis or lipid peroxidation, as evaluated by thiobarbituric acid-reactive substances measurements.

Amidines↗