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Biomedical subjects

M Monreal

Publications and source records attributed to M Monreal.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effects of freezing and canning of papaya slices on their carotenoid composition.

An HPLC study of the carotenoid composition of fresh, frozen and canned papaya fruit slices was done. There were no qualitative differences between the carotenoid patterns of fresh and frozen papaya fruit slices (cultivar Sunrise). The major carotenoids found in papaya extracts were lycopene and carotenol fatty acid esters of beta-cryptoxanthin and beta-cryptoxanthin-5, 6-epoxide. Other xanthophylls detected were beta-cryptoxanthin, trans-zeaxanthin and cryptoflavin. It was possible to determine the quantitative losses of carotenoids in papaya slices as a result of the freezing process and frozen storage, since samples of these fruits were available before processing. The pigment pattern of the canned product showed lycopene as being a major pigment. Thermal treatment induced the degradation of carotenol fatty acid esters of xanthophylls. The freezing and canning processing of papaya slices led to significant decreases in the total carotenoids quantified by HPLC, with frozen female slices and canned samples showing lower amounts of pigments. Hunter colour values of frozen slices were similar to those of fresh papaya fruit slices.

Carotenoids↗
PubMed1996

Pharmacological properties of hirudin and its derivatives. Potential clinical advantages over heparin.

Hirudin and its derivatives represent the first parenteral anticoagulants introduced since the discovery of heparin in the early 1900s. Hirudin, the naturally occurring anticoagulant of the leech, is a single peptide chain of 65 amino acids with a molecular weight of about 7000. Recombinant technology has developed methods to produce recombinant forms of hirudin (r-hirudin) in sufficient quantities for therapeutic use. Hirudin is a potent thrombin-specific inhibitor that forms equimolar complexes with thrombin. It represents a new anticoagulant agent in a field in which heparin has been the only available drug for many years. In contrast to heparin, hirudin does not require antithrombin III as a cofactor, is not inactivated by antiheparin proteins, has no direct effects on platelets and may also inactivate thrombin bound to clot or the subendothelium. In humans, experience with r-hirudin in preventing or treating venous thromboembolism is very preliminary. However, r-hirudin achieved promising results in patients with unstable angina, or following coronary angioplasty. In patients with acute myocardial infarction, 3 important clinical trials were stopped because of an excess of bleeding complications. At present, the discovery of a r-hirudin regimen that is more efficacious than heparin and at least as safe needs a reappraisal of the drug in further trials.

Angina, Unstable↗
PubMed1996

Upper extremity deep venous thrombosis in cancer patients with venous access devices--prophylaxis with a low molecular weight heparin (Fragmin).

Central venous access devices are often essential for the administration of chemotherapy to patients with malignancy, but its use has been associated with a number of complications, mainly thrombosis. The true incidence of upper extremity deep vein thrombosis (DVT) in this setting is difficult to estimate since there are very few studies in which DVT diagnosis was based on objective tests, but its sequelae include septic thrombophlebitis, loss of central venous access and pulmonary embolism. We performed an open, prospective study in which all cancer patients who underwent placement of a long-term Port-a-Cath (Pharmacia Deltec Inc) subclavian venous catheter were randomized to receive or not 2500 IU sc of Fragmin once daily 90 days. Venography was routinely performed 90 days after catheter insertion, or sooner if DVT symptoms had appeared. Our aims were: 1) to investigate the effectiveness of low doses of Fragmin in preventing catheter-related DVT; and 2) to try to confirm if patients with high platelet counts are at a higher risk to develop subclavian DVT, as previously suggested. On the recommendation of the Ethics Committee, patient recruitment was terminated earlier than planned: DVT developed in 1/16 patients (6%) taking Fragmin and 8/13 patients (62%) without prophylaxis (Relative Risk 6.75; 95% CI: 1.05-43.58; p = 0.002, Fisher exact test). No bleeding complications had developed. As for prediction of DVT, there was a tendency towards a higher platelet count in those patients who subsequently developed DVT, but differences failed to reach any statistical significance (286 +/- 145 vs 207 +/- 81 x 10(9)/1; p = 0.067). According to our experience, Fragmin at the dosage used proved to be both effective and safe in these patients.

Adult↗
PubMed1995

Platelet count, antiplatelet therapy and pulmonary embolism--a prospective study in patients with hip surgery.

Pulmonary embolism (PE) is a serious complication following hip surgery. Trials of antiplatelet thromboprophylaxis indicated a substantial reduction in PE rate, and we prospectively studied the effect of a combination of low-dose heparin and two different antiplatelets. Furthermore, our experience in previous studies suggested that platelet count (PC) levels could be useful to reliably suspect PE at a very early stage, and we prospectively tried to confirm our previous findings. Ours is a prospective study in 459 consecutive patients operated on because of hip fracture (265) or elective hip replacement (194), aimed to determine: 1) whether the benefits of antiplatelets plus heparin on PE outweigh the risks; 2) to assess the clinical usefulness of PC monitoring in these patients, so as to confirm whether PE could be recognized early. It was a prospective, randomized, double-blind study. All patients received unfractioned heparin (7500 IU sc twice daily, starting 2 h before operation). In addition, they received aspirin (200 mg thrice daily, with meals), Triflusal (300 mg thrice daily, with meals), or placebo. Real time B-mode ultrasonography (US) was performed on all patients on the 8-9th day after surgery. Venography was performed in patients with normal US, if clinical symptoms suggested venous thrombosis. Twelve out of the 459 patients (2.6%) had to discontinue prophylaxis, because of major bleeding (6 patients), or gastric intolerance (6 patients). There were no significant differences between groups in either deep vein thrombosis (26 patients (18%) with aspirin, 18 (12%) with Triflusal, 26 (17%) with placebo), or PE development (7 patients (5%) with aspirin, 3 (2%) with Triflusal, 8 (5%) taking placebo).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Effects of two different doses of hirudin on APTT, determined with eight different reagents.

The APTT has been considered the most suitable candidate to monitor the anticoagulant activity of hirudin. However, its use is hampered by problems of standardization, which make the results heavily dependent on the responsiveness of the reagent used. Our aim was to investigate if this different responsiveness of different reagents when added in vitro is to be confirmed in an ex vivo study. Two different doses of r-hirudin (CGP 39393), 0.3 mg/kg and 1 mg/kg, were administered subcutaneously to 20 New Zealand male rabbits, and the differences in prolongation of APTT 2 and 12 h later were compared, using 8 widely used commercial reagents. All groups exhibited a significant prolongation of APTT 2 h after sc administration of hirudin, both at low and high doses. But this prolongation persisted 12 h later only when the PTTa reagent (Boehringer Mannheim) was used. In general, hirudin prolonged the APTT most with the silica-based reagents. In a further study, we compared the same APTT reagents in an in vitro study in which normal pooled plasma was mixed with increasing amount of hirudin. We failed to confirm a higher sensitivity for silica-containing reagents. Thus, we conclude that subcutaneous administration of hirudin prolongs the APTT most with the silica-based reagents, but this effect is exclusive for the ex vivo model.

Animals↗
PubMed1995

Fine needle aspiration for flow cytometry immunophenotyping of non Hodgkin lymphoma.

The aim was to evaluate the usefulness of lymph node biopsies obtained by fine needle aspiration (FNA) for immunophenotyping of non Hodgkin lymphoma (NHL). Seventeen superficial and deep lymph node samples were fractioned for conventional cytological examination and immunophenotyping studies. Out of ten NHL, nine were readily detected by flow cytometry (FC), while failure on the remaining case was due to selective loss of large cell population, which is liable to occur with this procedure. A single case, which proved negative for all markers employed, was finally diagnosed by immunohistochemistry as germ cell tumor. The other six cases, presenting lymphoid population without phenotypic abnormalities, were diagnosed by cytology and/or histology as Hodgkin disease or hyperplasic disorders. To conclude, FC immunophenotyping seems to improve the efficacy of FNA in NHL diagnosis, whereas for Hodgkin disease and hyperplasic disorders, classic morphological criteria are more useful for differential diagnosis. Although FNA for FC immunophenotyping cannot replace histopathological examination for NHL diagnosis, it proves to be a useful tool for staging and follow up, making surgical procedures for sample collection unnecessary.

Biopsy, Needle↗
PubMed1995

Comparison of the effects of low-molecular-weight and unfractioned heparin in horses.

Thirty healthy male horses were allotted to 3 groups and treated blindly during 4 days. Group-1 horses received unfractioned calcium heparin (100 IU/kg of body weight, SC, q 12 h). Group-2 horses received a single dose of a low-molecular-weight heparin (50 anti-Xa IU/kg, SC) every morning, and a similar volume of saline solution every evening. Group-3 horses received the vehicle (saline solution), SC, every 12 hours. Citrated and EDTA-anticoagulated blood samples were collected before starting the medication (T-0) and once daily 3 hours after each morning injection (T-3, T-27, T-51, and T-75). The PCV, hemoglobin concentration, RBC and platelet counts, and clotting times (activated partial thromboplastin time and thrombin time) were determined, and a microscopic examination to detect hemagglutination was performed. Plasma concentration of heparin was measured by use of the antifactor Xa, activity assay. Bleeding time was determined on the first and fourth days, using a double-template method. The horses given unfractioned heparin had marked agglutination of erythrocytes after the first injection that became more pronounced as treatment progressed. Also, significant decrease in PCV, hemoglobin concentration, and RBC count was observed during treatment. Platelet count was significantly decreased after the first day, and clotting times were significantly prolonged. In contrast to the horses given unfractioned heparin, those given low-molecular-weight heparin did not have any agglutination of erythrocytes during the 4 days of treatment, and there were no significant changes in PCV, hemoglobin concentration, or RBC and platelet counts. Activated partial thromboplastin time increased slightly in the horses given low-molecular weight heparin, although the values remained within reference range. Both groups of horses achieved adequate concentrations of heparin in plasma for prophylactic purposes, but those given low-molecular-weight heparin achieved those values after the first injection. Bleeding times were not significantly different between heparin-treated horses and horses given saline solution during treatment. We conclude that low-molecular-weight heparin may be used more safely and conveniently in horses, because it does not affect equine erythrocytes, platelets, or clotting and bleeding times.

Animals↗
PubMed1994

Recurrent pulmonary embolism in patients treated because of acute venous thromboembolism: a prospective study.

OBJECTIVE: To evaluate the risk of pulmonary embolism (PE) despite adequate heparin therapy in a large series of patients with acute deep venous thrombosis and/or pulmonary embolism. DESIGN: Prospective study. SETTING: University Hospital Germans Trias i Pujol, Badalona, Spain. MATERIALS: 348 patients admitted because of deep venous thrombosis in the lower limbs and/or pulmonary embolism. A baseline lung scan was obtained initially in every patient, whether the original diagnosis was PE or deep vein thrombosis (DVT). Repeat chest X-ray and lung scans were obtained routinely at 8 days of heparin onset. OUTCOME MEASURES: The primary trial endpoint was a finding of confirmed, clinically apparent recurrent PE; in addition, laboratory evidence of subclinical PE at the repeat scan was also considered. RESULTS: PE recurrences were found in 23/348 patients (7%). No significant differences were found in age and sex distribution, or in the degree of DVT proximity between patients who developed and those who did not develop recurrences. Recurrent PE was more commonly found in patients with scintigraphic evidence of PE on admission, irrespectively of the original diagnosis being DVT or PE (18/151 vs. 3/155; p = 0.0005, Fisher's exact test). Recurrences were also more common in patients in whom thrombosis developed in the absence of any known risk factor (10/70 vs. 13/278; p = 0.007). The logistic regression analysis confirmed the statistical significance of these two clinical variables. CONCLUSIONS: Pulmonary embolism despite adequate heparin therapy is not an uncommon event. It appears possible to identify a subgroup of patients at a higher risk, and, modify treatment accordingly.

Adolescent↗
PubMed1994

Pulmonary embolism in patients with upper extremity DVT associated to venous central lines--a prospective study.

We performed a prospective study in 86 consecutive patients with central vein catheter-related deep venous thrombosis (DVT) of the upper extremity, to evaluate the prevalence of pulmonary embolism (PE), and to identify clinical variables that would increase the likelihood of developing PE in an individual patient. Since upper-extremity DVT was established, all patients received intravenous heparin therapy. Then, a ventilation-perfusion lung scan was obtained within 24 h of DVT diagnosis, whether respiratory symptoms were present or not. Six points of clinical information were recorded on entering in the study, and then compared with the scintigraphic findings: age, sex, the underlying disease, the catheter material, the character of the infusate, and the duration of cannulation. Thirteen patients were considered to have PE. Sixty-six patients were finally classified as having a normal lung scan, and 7 patients were excluded from the study (because of indeterminate lung scan 6; because of femoropopliteal thrombosis simultaneously present 1). Two out of the 13 patients with PE subsequently died because of recurrent, massive embolism, despite adequate heparin therapy. PE was more commonly present in patients with polyvinyle chloride or polyethylene catheters (10/38, 26%) as compared to patients with either polyurethane or siliconized catheters (3/41, 7%; p < 0.05, Chi-Square test; Odds Ratio = 4.52, 95% CI 1.01-23.07). We conclude that PE is not a rare event in these patients, and it may be life-threatening even despite adequate heparin therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Comparison of subcutaneous unfractionated heparin with a low molecular weight heparin (Fragmin) in patients with venous thromboembolism and contraindications to coumarin.

Intravenous heparin followed by oral anticoagulant therapy (e. g. with coumarin) is still the most widely used treatment for deep venous thromboembolism. Self-administered subcutaneous injections of heparin have been thought of as a promising alternative to coumarin, but the high doses required for ongoing prophylaxis have raised concerns about the possible development of bone disease. Certainly, long-term heparin therapy has been reported to cause osteoporosis in both laboratory animals and humans. This study aimed to compare the efficacy and safety of unfractionated (UF) heparin with that of a low molecular weight heparin (Fragmin, Kabi Pharmacia) in the prevention of recurrent deep venous thrombosis (DVT) and pulmonary embolism (PE) in a consecutive series of patients with contraindications to coumarin therapy. The patients comprised 40 men and 40 women, aged between 19 and 92 years (mean age, 68 years). They had all previously been diagnosed as having acute DVT and had been treated with conventional doses of heparin while in hospital. All patients had at least one of the following conditions: recent blood loss (either spontaneous or during admission while receiving heparin therapy); active gastroduodenal ulcer disease; psychological or physical inability or unwillingness to understand and accept the need for regular laboratory monitoring during coumarin treatment; chronic alcoholism; dementia; pregnancy; recent neurosurgery, and pericardial effusion; or were over 80 years of age. They were randomly allocated to receive either UF heparin, 10,000 IU s.c. b.d., or Fragmin, 5000 IU anti-Factor Xa s.c. b.d., for a period of 3-6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Deep venous thrombosis associated with necrotizing vasculitis].

The association of deep vein thrombosis with systemic necrotizing vasculitis is infrequent. Herein are referred two patients with microscopic polyarteritis and one patient with overlap syndrome who developed deep vein thrombosis which complicated in two cases with pulmonary embolism. The clinical features and the pathogenic mechanisms involved in this infrequent association are analyzed. In two patients the thrombosis was simultaneous with the diagnosis of vasculitis. In one patient deep vein thrombosis was the cause of hospital admission. Advanced age and thrombocytosis are factors associated to vasculitis, which may favor the development of thromboembolic disease. The presence of antiphospholipid syndrome was discarded. Although infrequent, this association should be considered because of the potential severe complications.

Aged↗
PubMed1993

Venographic assessment of deep vein thrombosis and risk of developing post-thrombotic syndrome: a prospective study.

It is well known that patients with deep vein thrombosis (DVT) constitute a risk group for development of pulmonary embolism. However, the relation of DVT and the extent thereof with the subsequent sequelae (post-thrombotic syndrome) are insufficiently investigated. We have prospectively studied a series of consecutive patients admitted because of DVT on lower limbs, trying to correlate venographic findings during acute DVT with post-thrombotic (PTS) symptoms that develop later. Seventy-nine patients (84 limbs) with acute DVT were followed-up in our out-patient clinic at 4-monthly intervals for 3 years. At each visit patients were carefully examined regarding the appearance of PTS symptoms and/or signs from the DVT-affected leg. Three years after discharge, presence of PTS signs was assessed according to a simple scoring system. And then correlated to venographic findings during acute DVT. Patients were classified as having no (37 legs), mild (30 legs), or severe PTS signs (17 legs). Patients with popliteal vein involvement showed a significantly higher incidence of PTS 3 years later (P < 0.001). The risk of PTS also increased as DVT extent increased (P < 0.001). Nevertheless, the logistic regression analysis showed that DVT location explained all the differences (P < 0.001). In other words, DVT extent was overriden by the significance of DVT location, being popliteal the only location that showed a relevant contribution to the PTS incidence (95% confidence interval = 2.49-71.5).

Acute Disease↗
PubMed1993

Occult cancer in patients with acute pulmonary embolism. A prospective study.

We prospectively studied 78 consecutive patients with acute pulmonary embolism (PE) to determine the most appropriate workup study for searching for hidden cancer. After a careful physical examination, the following tests were performed: erythrocyte sedimentation rate (ESR), complete blood cell counts, biochemistry, carcinoembryonic antigen levels, chest radiograph, upper gastrointestinal endoscopy, and abdominal ultrasound. If a malignant lesion was suspected, further appropriate tests were performed. After hospital discharge, periodic follow-up was performed on all patients in our outpatient clinic. A malignant lesion was detected in 9 of 78 patients: in 7 of them, cancer was diagnosed during the hospital admission because of acute PE. All but one of these 7 patients were asymptomatic, except for PE symptoms. In three of them some abnormalities on physical examination led to the diagnosis of cancer; in the remaining three patients the diagnosis was suspected from abnormal results of blood tests. Cancer was detected several months after hospital discharge in two additional patients: an esophageal cancer was diagnosed 5 months later in one of the 23 patients who refused endoscopy; and a colonic carcinoma was detected 21 months after hospital discharge in a patient in whom colonoscopy was not performed at the time of hospital admission. When considered overall, cancer was more commonly found in patients with "idiopathic" PE as compared with patients with known risk factors for PE development (6 of 21 patients vs 3 of 51 patients; p < 0.05). On the other hand, one patient died because of massive recurrent PE after a biopsy sample was obtained because of a prostatic node. Gross hematuria had developed shortly after biopsy, and any attempt to increase heparin doses was followed by recurrent hematuria. According to our experience, any decision about procedures that potentially involve bleeding should be carefully individualized in patients with acute PE.

Acute Disease↗
PubMed1993

[Normal values for hematological and hemostatic parameters in the rabbit. Determination of new parameters for experimental models of thrombosis and hemostasis].

PURPOSES: Assessment of normal haematological values in the rabbit using a semi-automatic analyser. Evaluation of new haemostatic parameters necessary for experimental models in thrombosis and haemostasis. MATERIAL AND METHODS: 20 New Zealand male rabbits of 2-2.5 kg were anaesthetized and blood was collected from the jugular vein. The following haematological determinations were carried out using a semi-automatic analyser: red blood cells count, haemoglobin, haematocrit, indexes, white blood cells count, platelet count and mean platelet volume. The parameters used to assess the physiological haemostasis in rabbit were: bleeding time, fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time; and others not yet determined in the rabbit: antithrombin III, thrombin-antithrombin complexes and F1+2 fragments to measure the basal thrombin-formation activity, and fibrin D-dimer and fibrinogen degradation products for fibrinolysis activity. RESULTS: The haematological results obtained were similar than with other techniques, but with no stress influence. Normal values for haemostatic parameters studied are shown, including the parameters for the determination of physiological thrombin-formation and fibrinolysis activity. F1+2 fragments and fibrinogen degradation products could not be evaluated. CONCLUSIONS: The haematological results obtained were completely normal. All the haemostatic parameters studied were found useful to determine the physiological activity of coagulation and fibrinolysis in the rabbit, and specially for experimental models of hypercoagulability and hyperfibrinolisys states.

Animals↗
PubMed1992

Deep venous thrombosis and the risk of pulmonary embolism. A systematic study.

The influence of several diseases and clinical conditions on the presence of pulmonary embolism (PE) in a large series of patients with deep venous thrombosis (DVT) in the lower extremities was analyzed prospectively. Lung scan findings from a series of 434 consecutive patients with DVT (with and without symptoms of PE) were studied and then correlated to five clinical variables: age, sex, elapsed time since clinical symptoms had appeared in the leg to diagnosis, degree of proximity of venous thrombus, and the presence or not of several risk factors that could have predisposed to thrombus development. According to scintigraphic findings, 164 patients were considered to have PE (asymptomatic in 76 of them), while 200 patients were classified as having only DVT. Lung scan was considered to be indeterminate for PE in 70 patients, and they were not included in the study. No differences were found in terms of age, sex, interval of time elapsed since onset of symptoms to diagnosis, or in the degree of proximity of the thrombus. However, several differences between groups were found when comparing the presence or absence of several predisposing factors for thrombosis: DVT developing in immobilized patients was associated with a significantly lower incidence of PE as compared with nonimmobilized patients (p = 0.005). Conversely, patients with a history of venous thromboembolism (VTE) had a significantly higher rate of embolism (31/51 vs 133/313; p = 0.01). On logistic regression analysis, a history of VTE showed a statistically significant association with more than a twofold higher risk of having PE for patients with such an antecedent. Our findings suggest that different pathophysiologic pathways could perhaps explain differences in embolic potential.

Causality↗
PubMed1992

Effects of inhaled platelet activating factor on bronchial responsiveness in patients with symptomatic and asymptomatic pulmonary embolism.

To determine the possible role of platelet-activating factor (PAF) in pulmonary embolism (PE), the reactivity of the airways to inhaled PAF, using doses ranging from 6.25 to 400 micrograms, was examined in 24 patients with a past episode of PE. Twelve of these patients had experienced acute respiratory insufficiency during the episode (with or without additional symptoms). None of the remaining 12 patients had experienced any respiratory symptoms during the PE episode. Diagnosis was established by means of a ventilation-perfusion lung scan performed when admitted to the hospital because of deep venous thrombosis (DVT) in the lower limbs. Nonspecific bronchial reactivity as measured by the response to bronchoprovocation testing with methacholine showed no significant differences between both groups. PAF caused a dose-dependent bronchoconstriction defined by at least a 35 percent decrease in specific airway conductance (SGaw) in all patients. The average dose of PAF needed to decrease SGaw 35 percent was significantly lower in patients who had had a symptomatic PE than in those with asymptomatic PE (p = 0.011). This finding suggests that patients who suffered from symptomatic PE may present a greater airway reactivity to inhaled PAF. This different behavior might explain the existence of some of the respiratory symptoms of PE, which could be attributed to PAF-related effects. However, additional studies are needed to evaluate the role of PAF in PE.

Administration, Inhalation↗