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Biomedical subjects

F Martín

Publications and source records attributed to F Martín.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Efficacy of direct paraffin embedding in cytological analysis of vitreous from proliferative vitreo-retinopathy (PVR)].

PURPOSE: To assess the efficacy of direct paraffin embedding in cytological analysis of vitreous samples in patients suffering from PVR, against the commonly used method for this purpose (cytospin). METHOD: Undiluted vitreous or vitreous fluids from 40 subsequent patients with PVR were collected and processed (samples collected from cassette at the end of aspiration line in final stage of vitrectomy process). 40 samples underwent cytospinning, 24 samples were paraffin embedded. Specimens were assessed by an expert ocular pathologist and tested samples were assigned to scoring and non scoring groups (where scoring means at least three cells per field in x60 magnification). RESULTS: All 24 paraffin embedding samples scored according to criteria while 36 of 40 cytospinned samples complied with scoring criteria. Differences were not statistically significant. Macrophages (87.5%) and pigmented cells (85%) were the most frequent findings. CONCLUSIONS: Direct paraffin embedding is useful for cytological studies in vitreous samples of PVR patients.

Humans↗
PubMed2001

[Comparison of different techniques for cytologic analysis of vitreous specimens].

PURPOSE: To assess the efficacy of four methods to study the cytology of vitreous samples, and to evaluate the most efficient for routine analysis and immunocytochemical staining. METHODS: Diluted and undiluted vitreous samples of 87 consecutive patients suffering vitreoretinal surgery for different diseases were analysed. The specimens were centrifugated and then processed through four different procedures: agar sandwich (29 cases), direct paraffin embedding (33 cases), cytospin preparations (82 cases) and cytoblock (8 cases). RESULTS: Evaluable material was obtained in: agar sandwich 18 out of 29 cases (62%), direct paraffin embedding 32 out of 33 cases (96.9%), cytospin 72 out of 82 cases (87.8%) and cytoblock 1 out of 8 cases (12.5%). CONCLUSIONS: Direct paraffin embedding and cytospin are the most efficient procedures for routine purposes. Agar sandwich technique seems to be useful for studying small pieces of tissue. Direct paraffin embedding and agar sandwich technique seems to be valuable for immunocytochemistry. After 8 cases processed with cytoblock, our experience did not show valuable results for processing vitreous samples.

Cytological Techniques↗
PubMed2001

[Distribution of hepatitis C virus genotypes among the hemodialysis population in the province of Alicante].

UNLABELLED: Hepatitis C virus (HCV) genotypes are irregularly distributed among the different geographic area and groups at risk. OBJECTIVE: To study the different HCV genotypes and subtypes of hemodialyzed patients from Alicante. METHODS: We studied 640 patients on haemodialysis (HD) and we determined the RNA-HCV and the genotypes in the 120 patients with antibodies against HCV (HCV-Ab). We compared the results with the genotypes of 1,370 patients from other groups at risk in the same geographic area. RESULTS: RNA-HCV was not found in the serum in 15% (18/120) of the patients on HD who were HCV-Ab positive. Prevalence of the different genotypes in the 102 patients with positive viral RNA was the following: 1b: 56.8% (58/102), 1a: 19.6% (20/102), 3: 17% (17/102), 2a-2c: 1.9 (2/102), 2b: 0.9% (1/102) 4: 2.9 (3/102), 5: 0.9% (1/102). In conclusion, the genotype 1b was the most frequent in the patients studied in all these areas, and was the same as in the rest of the country. This genotype has been associated with the most severe hepatic disease and poor response to treatment, affecting the prognosis of these patients. The most frequent genotypes in HD in Alicante were 1b, 3 and 1a. HCV genotypes distribution among the HD units was not uniform in the different geographic areas. HCV genotypes distribution in the HD population is similar to other groups at risk from the same geographic area.

Adult↗
PubMed2000

Nutrient modulation of polarized and sustained submembrane Ca2+ microgradients in mouse pancreatic islet cells.

The intracellular calcium concentration ([Ca2+]i) near the plasma membrane was measured in mouse pancreatic islet cells using confocal spot detection methods. Whereas small cytosolic Ca2+ gradients were observed with 3 mM glucose, a steeper sustained gradient restricted to domains beneath the plasma membrane (space constant, 0.67 micrometer) appeared with 16.7 mM glucose. When the membrane potential was clamped with increasing K+ concentrations (5, 20 and 40 mM), no [Ca2+]i gradients were observed in any case. Increasing glucose concentration (0, 5 and 16.7 mM) in the presence of 100 microM diazoxide, a K+ channel opener, plus 40 mM K+ induced steeper [Ca2+]i gradients, confirming the role of membrane potential-independent effects of glucose. Prevention of Ca2+ store refilling with 30 microM cyclopiazonic acid (CPA) or blockade of uniporter-mediated Ca2+ influx into the mitochondria with 1 microM carbonyl cyanide m-chlorophenyl hydrazone (CCCP) or 1 microM Ru-360 significantly reduced the steepness of the 16.7 mM glucose-induced [Ca2+]i gradients. Measured values of [Ca2+]i reached 6.74 +/- 0.67 microM at a distance of 0.5 micrometer from the plasma membrane and decayed to 0.27 +/- 0.03 microM at a distance of 2 micrometer. Mathematically processed values at 0.25 and 0 micrometer gave a higher [Ca2+]i, reaching 8.18 +/- 0.86 and 10.05 +/- 0.98 microM, respectively. The results presented indicate that glucose metabolism generates [Ca2+]i microgradients, which reach values of around 10 microM, and whose regulation requires the involvement of both mitochondrial Ca2+ uptake and endoplasmic reticulum Ca2+ stores.

Aniline Compounds↗
PubMed2000

[Undiagnosed diabetes and impaired glucose metabolism on high risk Spanish population. The IGT study].

BACKGROUND: To estimate the prevalence of undiagnosed diabetes and impaired glucose metabolism on high risk Spanish population, contrasting phenotypic features according to both sets of criteria, World Health Organization (WHO) and American Diabetes Association (ADA). SUBJECTS AND METHODS: Cross-sectional, multicentre (10 health-care centres, 230,000 inhabitants), selective risk-factor study. WHO diagnoses (normal, impaired glucose tolerance [IGT] and diabetes) were based on the 2 h plasma glucose (2hPG) following a 75 g oral glucose tolerance test (OGTT) and ADA diagnoses according the fasting plasma glucose (FPG) (normal, impaired FPG and diabetes). Prevalence, diagnostic overlap index and 22 clinical and biological parameters were compared. RESULTS: The study included 580 subjects (330 women), mean age 58.1 years and body mass index 31.2 kg/m2, 292 (50.3%) with only one risk factor and 288 (49.7%) with two or more risk factors. WHO diagnoses were: 291 (50.2%) normal glucose tolerance (95% CI: 46.2-54.2%), 157 (27.1%) IGT (23.5-30.7%) and 132 (22.7%) diabetes (19.3-26.1%). ADA diagnoses were: 355 (61.2%) normal FPG (57.2-65.2%), 146 (25.2%) IFG (21.7-28.7%) and 79 (13.6%) diabetes (10.9-16.3%). The prevalence of diabetes decreased 9.1% (from -11.4 to -6.8%). The diagnostic overlap was 33.5% for diabetes and 19.3% for impaired glucose homeostasis (IGT-FPG). Omitting the OGTT half the diabetic subjects with 2hPG > or = 200 mg/dl (11.1 mM) but FPG < 126 mg/dl (7 mM) would remain undiagnosed. By changing screening criteria (FPG instead of 2hPG) the risk related to traditional factors such as age or a first-degree relative with diabetes would reduce. CONCLUSIONS: Applying ADA criteria, the high prevalence of undiagnosed glucose abnormalities would decrease. These results suggest that it is strongly advisable the continued use of the 2hPG for diabetes screening on high risk Spanish population.

Blood Glucose↗
PubMed2000

Nutrient toxicity in pancreatic beta-cell dysfunction.

Nutrients, such as glucose and fatty acids, have a dual effect on pancreatic beta-cell function. Acute administration of high glucose concentrations to pancreatic beta-cells stimulates insulin secretion. In addition, short term exposure of this cell type to dietary fatty acids potentiates glucose-induced insulin release. On the other hand, long-term exposure to these nutrients causes impaired insulin secretion, characterized by elevated exocytosis at low concentrations of glucose and no response when glucose increases in the extracellular medium. In addition, other phenotypic changes are observed in these conditions. One major step in linking these phenotypic changes to the diabetic pathology has been the recognition of both glucose and fatty acids as key modulators of beta-cell gene expression. This could explain the adaptative response of the cell to sustained nutrient concentration. Once this phase is exhausted, the beta-cell becomes progressively unresponsive to glucose and this alteration is accompanied by the irreversible induction of apoptotic programs. The aim of this review is to present actual data concerning the development of the toxicity to the main nutrients glucose and fatty acids in the pancreatic beta-cell and to find a possible link to the development of type 2 diabetes.

Animals↗
PubMed2000

Noninvasive assessment of cardiac risk in type I diabetic patients being evaluated for combined pancreas-kidney transplantation using dipyridamole-MIBI perfusion tomographic scintigraphy.

This study was performed to determine the value of dipyridamole-99m Tc-methoxy-isobutyl isonitrile perfusion (99mTC-MIBI) tomographic scintigraphy in the assessment of cardiac risk in patients being evaluated prior to combined pancreas-kidney transplantation (PKT). We performed perfusion tomographic scintigraphy using single photon emission computed tomography (SPECT) on 77 patients. The tomographic images did not show clinically relevant findings in 65 patients. In the remaining 12 patients, coronary arteriography was performed: 2 showed normal results, 4 showed no stenosis, and 6 showed significant stenosis ( > or = 70%). Seventy-two patients underwent PKT. During the follow-up (6-48 months), there were seven cardiac events, 4 patients with significant stenosis, and 3 with nonsignificant stenosis upon coronary arteriography, and all had pathological tomographic images. 99mTc-MIBI tomographic scintigraphy may be useful in identifying patients at low risk of incurring cardiac events after PKT and may, in a large group of patients, obviate the need for routine coronary angiography.

Adult↗
PubMed2000

Engineering pancreatic islets.

Pancreatic islets are neuroendocrine organs that control blood glucose homeostasis. The precise interplay of a heterogeneous group of cell populations (beta, alpha, delta and PP cells) results in the fine-tuned release of counterbalanced hormones (insulin, glucagon, somatostatin and pancreatic polypeptide respectively). Under the premises of detailed knowledge of the physiological basis underlying this behaviour, two lines of investigation might be inferred: generating computational and operational models to explain and predict this behaviour and engineering islet cells to reconstruct pancreatic endocrine function. Whilst the former is being fuelled by new computational strategies, giving biophysicists the possibility of modelling a system in which new "emergent" properties appear, the latter is benefiting from the useful tools and strategic knowledge achieved by molecular, cell and developmental biologists. This includes using tumour cell lines, engineering islet cell precursors, knowledge of the mechanisms of differentiation, regeneration and growth and, finally, therapeutic cloning of human tissues. Gaining deep physiological understanding of the basis governing these processes is instrumental for engineering new pancreatic islets.

Animals↗
PubMed2000

[Treatment of metastatic bone pain with repeated doses of strontium-89 in patients with prostate neoplasm].

This study has aimed to evaluate the usefulness of repeated treatment with 89Sr in patients with prostate neoplasm and metastatic bone pain. Seventeen patients with partial or complete response after the first dose were retreated with two or more doses (total of 39 doses). The Karnofsky functional status, pain and degree of analgesia were assessed. After the first dose the response was good in 68% of the patients and partial in 32%. After the second dose, the response was good in 62% of the patients, partial in 15% and there was no response in 23% of the cases. The pre-treatment Karnofsky functional status and duration of the effect of 89Sr was lower after the second dose (p = 0.03, p = 0.02), but there were no statistically significant differences in the type of response. In conclusion, re-treatment with 89Sr can be administered safely and with a similar response to that achieved after the first dose.

Aged↗
PubMed2000

[Perforating epicardial lead: atypical evolution].

Endocarditis related to pacemaker lead is a rare complication of permanent transvenous pacing, of which the diagnosis is carried out with the presence of verrucae in echocardiography and positive blood cultures, its treatment being mixed -medical and surgical- because the isolated medical treatment is rarely successful and the lead should be extracted. We present the case of recurrent endocarditis of several years of evolution, in the which it was not possible to extract of the electrode due to the special characteristics of the patiente (epicardial lead perforating into right atrial).

Aged↗
PubMed2000

Arthroscopic repair of the posterior cruciate ligament: two techniques.

SUMMARY: Isolated posterior cruciate ligament injuries are rare and their treatment is controversial. These lesions have commonly been treated by open reduction and internal fixation using a posterior approach. However, this approach makes it difficult to explore other combined injuries of the knee joint. We report 2 cases of posterior cruciate ligament avulsion of the tibia that were arthroscopically reduced and fixed using 2 different methods, cannulated screws and tension band wire.

Adult↗
PubMed2000

Usefulness of strontium-89 for bone pain palliation in metastatic breast cancer patients.

Most studies of prostate cancer have shown that strontium-89 chloride (89Sr) is effective in the palliation of metastatic bone pain, refractory to conventional analgesia. The aim of this study was to evaluate the usefulness of 89Sr for bone pain palliation in breast cancer patients. Forty women were treated with 148 MBq of 89Sr. Six patients were retreated, receiving two or more doses. The Karnofsky performance status was assessed and pain and analgesia were scored on scales of 9 and 5 points, respectively. The efficacy of 89Sr was evaluated at 3 months of treatment. The response was good in 60% of the patients and partial in 32%; there was no response in the remaining 8% (pre-treatment Karnofsky < or = 60). The duration of the response was 120+/-143 days. In the patients retreated, the response was good in 83% and partial in 17%, without significant differences compared with the first dose, but the pre-treatment Karnofsky and the duration of the efficacy were lower (P < 0.05). A transient and slight decrease of leukocyte and platelet counts after the first month of treatment with 59Sr was observed. In conclusion, breast cancer patients with metastatic bone pain can benefit from therapy with 89Sr. If necessary, the treatment may be repeated safely and with the same efficacy as is achieved after the first dose. A low functional performance status could be a cause of the lower effectiveness of 89Sr.

Aged↗
PubMed2000

Junctional communication of pancreatic beta cells contributes to the control of insulin secretion and glucose tolerance.

Proper insulin secretion requires the coordinated functioning of the numerous beta cells that form pancreatic islets. This coordination depends on a network of communication mechanisms whereby beta cells interact with extracellular signals and adjacent cells via connexin channels. To assess whether connexin-dependent communication plays a role in vivo, we have developed transgenic mice in which connexin 32 (Cx32), one of the vertebrate connexins found in the pancreas, is expressed in beta cells. We show that the altered beta-cell coupling that results from this expression causes reduced insulin secretion in response to physiologically relevant concentrations of glucose and abnormal tolerance to the sugar. These alterations were observed in spite of normal numbers of islets, increased insulin content, and preserved secretory response to glucose by individual beta cells. Moreover, glucose-stimulated islets showed improved electrical synchronization of these cells and increased cytosolic levels of Ca(2+). The results show that connexins contribute to the control of beta cells in vivo and that their excess is detrimental for insulin secretion.

Animals↗
PubMed2000

Insulin-secreting cells derived from embryonic stem cells normalize glycemia in streptozotocin-induced diabetic mice.

Embryonic stem (ES) cells display the ability to differentiate in vitro into a variety of cell lineages. Using a cell-trapping system, we have obtained an insulin-secreting cell clone from undifferentiated ES cells. The construction used allows the expression of a neomycin selection system under the control of the regulatory regions of the human insulin gene. The chimeric gene also contained a hygromycin resistance gene (pGK-hygro) to select transfected cells. A resulting clone (IB/3x-99) containing 16.5 ng/microg protein of total insulin displays regulated hormone secretion in vitro in the presence of various secretagogues. Clusters obtained from this clone were implanted (1 x 10(6) cells) in the spleen of streptozotocin-induced diabetic animals. Transplanted animals correct hyperglycemia within 1 week and restore body weight in 4 weeks. Whereas an intraperitoneal glucose tolerance test showed a slower recovery in transplanted versus control mice, blood glucose normalization after a challenge meal was similar. This approach opens new possibilities for tissue transplantation in the treatment of type 1 and type 2 diabetes and offers an alternative to gene therapy.

Animals↗