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Biomedical subjects

M Mares

Publications and source records attributed to M Mares.

32 records · Page 2Linked to original sources
PubMed1991

Hemorheological study in patients with coronary artery disease.

Hemorheological parameters (viscosity of whole blood, plasma viscosity, hematocrit, velocity of red blood cells) were studied in 30 patients with coronary artery disease (15 patients with acute myocardial infarction, 15 patients with chronic angina), 14 subjects at high risk for ischemic heart disease and 14 normal volunteers matched for sex and age. Viscosity of whole blood was high in all coronary disease patients and in high-risk subjects as compared with controls. Velocity of red blood cells was significantly decreased in these patients. On the other hand, plasma viscosity and fibrinogen values were in the normal range in both groups and hematocrit was only slightly elevated in patients with angina. Furthermore, there were no changes in rheological parameters during the period of observation (1 week). We can suppose that the hyperviscosity is due, above all, to the decreased red blood cell deformability both in coronary disease patients but also in high-risk subjects. It is probable that red blood cell damage is present before the acute ischemic event, and that is a preexisting cause and not a consequence of it.

Angina Pectoris↗
PubMed1991

Portal vein thrombosis in a patient with severe haemophilia A and post-hepatitis liver cirrhosis.

The occurrence of a portal vein thrombosis in a haemophilia A patient is reported. The patient, a 53 year old male, had been followed by us for the past 20 years in our out-patient Clinic. He was hospitalized recently for a suspected hepatic cirrhosis. Severe ascites, hepato-splenomegaly together with weight loss and mild fever were present. During the hospitalization, an ultrasound and CT scan of the liver confirmed the cirrhotic pattern and showed the presence of a portal vein thrombosis. There were no changes in the underlying coagulation defect, in fact, the patient had recurrent haemarthrosis. Furthermore, with the ultrasound examination, some focal hepatic lesions--probably due to a hepatocellular carcinoma--were also observed. The patient died because of massive haematemesis due to rupture of oesophageal varices.

Carcinoma, Hepatocellular↗
PubMed1991

Effect of buflomedil, dipyridamole and indobufene on hemorrheologic and blood coagulation parameters in patients who underwent vascular surgery for severe atherosclerosis.

We studied 30 patients (age range 58 to 64 years) who underwent vascular surgery for peripheral vascular disease (24 patients) and for carotid stenosis (6 patients). At the time of the study, all subjects have been taking antiplatelet agents for at least three months. They were divided into three groups of ten patients each: the first group received buflomedil (BUF), the second dipyridamole (DIP) and the third indobufene (IND), as treatment before vascular surgery. We investigated the influence of these drugs on hemorrheologic (hematocrit, whole blood and plasma viscosity) and blood coagulation (partial thromboplastin time, prothrombin time and bleeding time) parameters in all patients. In our experience, none of the three drugs influenced any tested parameters, which were within normal limits: among them we noted only a statistically significant difference in bleeding time between patients treated with BUF and IND.

Arteriosclerosis↗
PubMed1991

S-S bridges of cathepsin B and H from bovine spleen: a basis for cathepsin B model building and possible functional implications for discrimination between exo- and endopeptidase activities among cathepsins B, H and L.

Bovine spleen cathepsin B contains 7 disulfide bridges. Using different chemical and enzymatic cleavage methods we isolated fragments representing the individual disulfides: Cys14-Cys43, Cys26-Cys71, Cys62-Cys128, Cys63-Cys67, Cys100-Cys132, Cys108-Cys119, and Cys148-Cys252. A similar line of approach was applied to determine the S-S bridges of bovine spleen cathepsin H: Cys23-Cys66, Cys57-Cys99, Cys157-Cys207, and Cys212-Cys5A, where Cys5A is located in the propart portion of the procathepsin H chain. On the basis of the knowledge of the S-S bridges of cathepsin B a novel sequence alignment of papain and cathepsin B has been proposed. This enabled us to construct a reasonable 3D-model of cathepsin B and propose the region (a 18 residue insertion between Glu89 and Gly90 of papain) responsible for the carboxypeptidase activity of cathepsin B functioning as a "closure". A similar approach was applied to explain the aminopeptidase activity of cathepsin H. A general model of steric regulation of accessibility of the preformed "endopeptidase-like" binding cleft by distant parts of the polypeptide chain of the proteinases discussed is proposed as a factor determining the mode of binding and thus cleavage of polypeptide substrates.

Amino Acid Sequence↗
PubMed1991

Decrease of fibrinogen in patients with peripheral atherosclerotic disease by ticlopidine.

Ticlopidine (Ticlodone: CAS 55142-85-3) is able to develop a positive effect on claudication in patients affected by peripheral atherosclerotic disease (PAD). It is also known that ticlopidine decreases fibrinogen levels in plasma. 15 PAD patients treated with ticlopidine for 3 months were studied, evaluating the drug's effect both on maximum walking distance and on fibrinogen. Plasma fibrinogen as coagulable protein, fibrinogen antigen (Partigen method), 125I-fibrinogen survival, euglobulin lysis time and plasminogen were determined with the aim of clarifying if the decrease of plasma fibrinogen induced by ticlopidine is due to an increased destruction of a decreased production of the molecule. The normal levels of all tests before and after therapy both in ticlopidine treated patients and in the control group (acetylsalicylic acid + dipyridamol) indicate that the two hypotheses are not true. It is proposed that ticlopidine developing the known effect in decreasing the binding of fibrinogen to platelets induces a decrease only of activated fibrinogen.

Adult↗
PubMed1990

Rhinophyma-like cryptococcal infection as an early manifestation of AIDS in a hemophilia B patient.

A hemophilia B patient, seropositive for HIV antibodies since 1984, came to us in March 1989 with a severe necrotizing lesion of the nose. It was an erythematous lesion and looked like rhinophyma. Microbiological examination of the skin biopsy showed the presence of Cryptococcus neoformans. At the time of the study, the patient was in partial remission after 2 weeks of therapy with fluconazole per os 400 mg/day. He will be treated with the same therapy at maintenance dose (200 mg/day) for a long period.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Variability of plasma viscosity in monoclonal IgM gammopathies.

Hyperviscosity syndromes can caused by both plasmatic and cellular factors. We have studied 20 patients affected by IgM gammopathy of different origin and 12 healthy subjects matched for sex and age, in order to evaluate the relation between paraprotein levels and plasma viscosity. We have observed a significant plasma viscosity increase only in 14 patients with monoclonal IgMk gammopathy. In the same patients was also evident an hyperviscosity syndrome. In the other 6 patients, with monoclonal IgM or polyclonal gammopathy and without clinical symptoms, plasma viscosity was only slightly increased. We have also observed a significant correlation between IgM and light chains (kappa, lambda) serum level and increased plasma viscosity. These results suggest that one can't consider all IgM gammopathies as cause of hyperviscosity syndrome.

Aged↗
PubMed1990

Branch retinal vein occlusion: the pathogenetic role of blood viscosity.

The pathogenesis of branch retinal vein occlusion has not been completely clarified. The role of abnormal blood viscosity in the appearance and evolution of the disease has recently been advocated. We studied 54 patients with long-standing branch retinal vein occlusion from a hemorrheologic point of view. Depending on the extension of retinal ischemia, two subgroups were identified. Hematocrit, blood and plasma viscosity, whole blood filterability, cell deformability, and fibrinogen levels were investigated. Thirty-five subjects of similar age, sex, and risk factors of diabetes and hypertension served as controls. Our results showed that blood viscosity is higher in patients with occlusion and particularly in those with severe retinal ischemia. Statistical analysis showed a direct correlation between blood viscosity and hematocrit.

Adult↗
PubMed1989

Primary structure of cathepsin D inhibitor from potatoes and its structure relationship to soybean trypsin inhibitor family.

A novel effective procedure for the purification of cathepsin D inhibitor from potatoes (PDI) was developed. The amino acid sequence of PDI was determined by analysis of the cyanogen bromide digest and of the limited tryptic and chymotryptic digest of the protein. The inhibitor is a single polypeptide chain protein consisting of 188 residues with a simple sugar moiety attached to Asn-19. The tentative disulfide pairings are also suggested. The sequence data clearly indicate that PDI is homologous with the soybean trypsin inhibitor (STI) (Kunitz) family. The active center of PDI for trypsin inhibition was identified as Pro-Val-Arg-Phe in analogy to STI.

Amino Acid Sequence↗
PubMed1989

[Erythrocyte filterability and relative viscosity in liver cirrhosis and chronic hepatitis].

Fifty patients with liver disease, of whom twenty-four had chronic active hepatitis and twenty-three had liver cirrhosis, were studied and compared with thirty-nine age- and sex-matched controls. Whole blood, plasma and their relative viscosities and the main factors capable of influencing these parameters (Ht, fibrinogen, triglycerides, cholesterol, plasma glucose, total proteins and gamma-globulins) were tested. Whole blood filterability time and velocity of red blood cells (VRBC) were also determined. In ten patients deformability of erythrocytes was determined both in whole blood and in suspensions of RBC in buffer at a Ht of 10%. Whole blood filterability time was significantly increased in all subjects with liver disease. Corrected filterability time was increased only in the cirrhotic group associated with a significant decrease of Ht and fibrinogen and a slight increase in gamma globulins and plasma viscosity. Whole blood viscosity was in the normal range while relative viscosity was decreased in all patients. These findings suggest that both shape alterations of red cells (such as echinocytic shape) and modifications of plasma proteins probably lead to a decrease of red cell filtration in cirrhotic patients.

Adult↗
PubMed1987

Fibrinolytic behavior in long-standing branch retinal vein occlusion.

The aim of our study was to evaluate the fibrinolytic system in patients with retinal branch vein occlusion (RVO). The following tests were carried out: prothrombin time, partial thromboplastin time (PTT), fibrinogen degradation products, euglobulin lysis time, fibrinogen, pasminogen, antithrombin III, alpha 2-antiplasmin and alpha 2-macroglobulin. Comparing the results of patients with those of normal controls, only the fibrinogen increase and PTT shortening were significantly different. All other tests taken into account were within normal limits. Only the patients without other associated diseases (diabetes or hypertension) showed a significant activation of fibrinolysis (either with respect to normal or to other RVO patient groups). In conclusion, no important fibrinolytic impairment was seen in our longstanding RVO patients. Fibrinolytic activation seen in patients without verified associated diseases may be related to the presence of a sound endothelium, still able to release plasminogen activators in response to RVO. The fibrinogen and PTT changes in RVO were probably due to other associated diseases.

Aged↗
PubMed1987

Antimicrobial activity of benzylisoquinoline alkaloids.

The antimicrobial in vitro activity of 14 benzylisoquinoline alkaloids was investigated by agar diffusion and agar dilution methods against several genera of microorganisms that included Streptococcus, Staphylococcus, Bacillus, Lysteria, Escherichia, Salmonella, Klebsiella, Pseudomonas, Enterobacter, Serratia, Shigella, Mycobacterium and Candida. Anolobine was the most active compound against grampositive bacteria with MIC90 between 12 and 50 mg/l; less active were anonaine, lysicamine and liriodenine. All the alkaloids of the noraporphine and oxoaporphine groups, with the exception of isopiline, showed activity against Mycobacterium phlei (MIC 6-25 mg/l). Candida albicans ATCC26555 was inhibited by anonaine, nornantenine and xylopine (MIC 3-12 mg/l). None of the alkaloids tested had a significant activity against gramnegative rods. The action against susceptible microorganisms was bactericidal.

Alkaloids↗
PubMedDate not supplied

Long-term treatment of refractory HIV-related immune thrombocytopenia in a patient with haemophilia A.

Haemophilia A patient developed symptomatic immune thrombocytopenia 5 years after HIV seroconversion without any progression of the viral disease. He displayed major bleeding with less than 30 x 10(9) platelets/l. No increase in platelet count was obtained using steroids, azidothymidine and alpha-interferon, while the patient was responsive only to high-dose intravenous immunoglobulins (IVGG). The patient remained responsive to IVGG for 1 year, and the repeated infusions of immunoglobulins were effective in safely maintaining the platelet count, with peak counts above 100 x 10(9)/l. On the contrary, after a single course of six plasma exchanges the patient became symptomatic and completely refractory to IVGG during the next month. In conclusion, IVGG could be effectively used in a long-term regimen in haemophiliacs with refractory HIV-ITP to avoid the risk of haemorrhages and to delay splenectomy.

Adult↗