Search PubMed⌕ Search

Biomedical subjects

M Porta

Publications and source records attributed to M Porta.

At least 163 records · Page 9Linked to original sources
PubMed1984

[Blood coagulation changes and pathogenesis of diabetic retinopathy. Recent advances].

In this review the most recent advances in blood coagulation and chronic complications of diabetes mellitus are discussed. Numerous research workers have reported abnormalities in the mechanisms of platelet activation, endothelial cell function, plasma coagulation and fibrinolysis. However, the data available today cannot as yet be interpreted in terms of pathogenesis of retinopathy or any other chronic manifestation of the disease. Consequently, there is at present no rationale for pharmacological prevention or treatment.

Anticoagulants↗
PubMed1984

A simple quantitative estimate of the function of radiolabelled platelets.

The function ex vivo of autologous platelets, labelled with 111In, was evaluated at various times following injection by comparing the retention on foreign surfaces of radioactivity with the retention of total platelets (represented almost entirely by unlabelled and therefore unmanipulated platelets) after the application of fresh un-anticoagulated whole blood to (a) filter paper and (b) glass bead columns. Relative retentions were similar for the two materials, with labelled platelet retention being about 80% that of native platelet retention. Prior to injection, when labelled platelets were returned to an excess of freshly drawn whole blood, retention of radioactivity was greater than that of native platelets with a ratio significantly greater than that seen with labelled platelets tested ex vivo. Filter paper retention provides a simple technique which may be useful for the evaluation of labelled platelet function as a function of platelet age and also, with further standardisation, as an inexpensive rapid test of unlabelled platelet function.

Blood Platelets↗
PubMed1984

Drugs in the Spanish health system.

This paper presents data on drug consumption in Spain, analyzed from a cultural as well as from a medical point of view. The overuse of medicines is an economic rather than a pharmaceutical problem, and the main characteristic of drug use in Spain seems to be the misuse of pharmacologic therapeutic strategies. Four factors which influence the quantity and quality of drug consumption are identified and analyzed: 1) the structure of the primary health care system, 2) general requirements for marketing drugs and the characteristics of pharmaceutical supply, 3) information about drugs used by health professionals, and 4) development and activities--pre-graduate teaching and continuing education--in the field of clinical pharmacology. Some recent activities in this area are also presented. These are intended as a contribution to the development of clinical pharmacology with the aim of turning benefit-risk ratios to the side of the benefit, through the promotion of a more rational drug therapy.

Drug Therapy↗
PubMed1984

Quantitative and qualitative assessment of plasma von Willebrand factor variations, as induced by forearm venous stasis in patients with diabetic microangiopathy.

Plasma von Willebrand factor was studied for quantitative and qualitative assessment in basal conditions and after release from the endothelium, as elicited by venous stasis of the forearm, in 8 healthy subjects and 8 patients with diabetic microangiopathy. von Willebrand factor was measured as factor VIII-related antigen (VIII R:Ag) and ristocetin co-factor (VIII R:Co). Its molecular size distribution was evaluated by bidimensional immunoelectrophoresis. The patients had higher basal levels of VIII R:Ag (171 +/- 45% vs 64 +/- 11% of plasma pooled from 20 healthy donors, p less than 0.05) and VIII R:Co (144 +/- 11% vs 88 +/- 8%, p less than 0.01). After stasis, both moieties increased significantly in the 2 groups, remaining higher in the patients (VIII R:Ag = 292 +/- 74% vs 89 +/- 18%, p = 0.01; VIII R:Co = 216 +/- 25% vs 116 +/- 10%, p less than 0.01). No differences in the molecular size distribution were observed between patients and controls, nor within the 2 groups before and after stasis. It is concluded that, in diabetic microangiopathy, the endothelial cells synthesize and store increased amounts of structurally normal von Willebrand factor.

Aged↗
PubMed1983

A study of platelet-relevant parameters in patients with diabetic microangiopathy.

In 16 diabetic patients with microangiopathy, survival of 111In-labelled autologous platelets, mean platelet volume, megathrombocyte index, spontaneous and ADP-induced platelet aggregation, platelet retention, beta-thromboglobulin, von Willebrand factor and factor VIII-related antigen were measured; the splenic uptake of radioactive label was quantitated in six patients. Compared with normal subjects, increased platelet aggregation (p less than 0.01), von Willebrand factor (p less than 0.02) and factor VIII-related antigen (p less than 0.02) were observed. Platelet survival was shortened in two patients. It correlated inversely with the splenic radioactivity uptake (r = -0.95; p less than 0.01), suggesting that platelets ended their life in the spleen, not in the microcirculation. No significant relationships were found between the various tests performed, nor between these and the severity of microangiopathy or other clinical data. In spite of the evidence for altered platelet function in patients with diabetic microangiopathy, currently available tests are not specific enough to clarify the nature of these changes or their possible pathogenic significance.

Adult↗
PubMed1983

Utilization of antihypertensive drugs in certain European countries.

The consumption of various groups of antihypertensive drugs in Spain during the period 1977-1981 has been measured by the DDD method. The total consumption of the drugs did not change much during this time. Combinations of thiazides with other hypotensives accounted for more than half the total antihypertensive drugs used. The consumption of rauwolfia and its derivatives, and of dihydralazine, was higher than of beta-blockers and methyldopa. Total consumption of antihypertensives in 1981 was 37.5 DDDs/1 000 inhab/day, which was much lower than in Denmark (136.6 DDDs/1 000 inhab/day), Finland (114.5), Iceland (92.2), Norway (89.4) and Sweden (138.7). Wide qualitative differences between countries were also identified. Although other factors may play a role, it is suggested that these striking differences may be due to differences in general health policy and in the pharmaceutical markets.

Antihypertensive Agents↗
PubMed1983

Drug utilization studies: a tool for determining the effectiveness of drug use.

To evaluate the quality of the consumption of medicines in Spain, its potential efficacy, and its evolution during the last years, an assessment of the 'intrinsic value' of the most sold pharmaceutical specialities (amounting to more than 50% of total pharmaceutical market) was carried out. A panel of five clinical pharmacologist classified medicines, according to their intrinsic value, in four groups: (i) 'high value' (41% of analyzed medicines in 1980); (ii) 'relative value' (12% in 1980); (iii) 'doubtful value' (3%); (iv) 'no value' (23%), and (v) 'unacceptable value' (21%). Drugs were also classified according to their expected potential of use; and three groups were formed: (i) 'high' (32%); (ii) 'relatively high' (14%), and (iii) 'reduced' (10%). A fourth group of 'not applicable' (44%) in this classification was formed with pharmaceuticals considered unvaluable or unacceptable in the first classification. The results of this study suggest that this kind of analysis may be a useful tool to evaluate the efficacy of drugs in the community, and to identify priorities and guidelines in the selection of drugs in each country.

Drug Therapy↗
PubMed1983

Acute severe poisoning in Spain: clinical outcome related to the implicated drugs.

The 91 patients over the age of 10 (57 women and 32 men) with severe self-poisoning admitted to the ICU of a general hospital in Barcelona during the period 1974-1980 have been retrospectively studied. Previous suicidal attempts have been identified among 32 patients; 26 patients presented a history of personality disorders, and 19 had a neurological disease, a chronic physical illness, or a history of alcoholism. Sedative-hypnotic drugs were involved in about half the number of cases, and one fifth of total cases were due to tricyclic antidepressants and phenothiazines. Paracetamol was only involved in 2 cases, and heroin in another 2 cases. Many of the most severe morbidity manifestations were related to overdoses by intermediate-acting barbiturates. Two out of a total of 5 deaths were related to butalbitone overdose. Butalbitone had been ingested as a fixed-dose combination containing butalbitone, propyphenazone, and caffeine, which is freely dispensed as an analgesic in Spain.

Adult↗
PubMed1982

Efficacy and tolerance of ivermectin in human onchocerciasis.

Initial clinical studies in 32 Senegalese subjects have demonstrated the efficacy of ivermectin in Onchocerca volvulus infection (river blindness). Although O. volvulus microfilariae in skin snips were not reduced in number after single oral doses of 5 micrograms or 10 micrograms/kg body-weight, they were greatly reduced in all subjects after single oral doses of 30 micrograms or 50 micrograms/kg and were eliminated completely in 6 of th 8 subjects who received the 50 micrograms/kg dose. All subjects tolerated the drug well. Transient pruritus which did not require treatment was observed on the day the dose was given in 2 of the 8 subjects after the 30 micrograms/kg dose and in 4 of the 8 who received the 50 micrograms/kg dose. Ivermectin produced no abnormal laboratory results.

Adult↗
PubMed1982

Availability of endothelial von Willebrand factor and platelet function in diabetic patients infused with a vasopressin analogue.

Acute release of von Willebrand factor and its immunologically detected correspondent, factor VIII-related antigen, from the endothelial cells into the circulation was induced by an infusion of 1-deamino-8-D-arginine vasopressin in eight normal subjects and eight insulin-dependent diabetic patients. The patients had higher basal levels of von Willebrand factor (140 +/- 13%) and VIII-related antigen (112 +/- 18%) than the normal subjects (95 +/- 5% and 70 +/- 8%, respectively). 1-deamino-8-D-arginine vasopressin induced a two-fold rise of these levels in both groups, von Willebrand factor/VIII-related antigen remaining higher in the diabetic patients throughout the experiment. In the normal subjects, platelet retention in glass bead columns increased soon after the infusion but returned to basal values after 2 h. In the patients, it remained high at the end of the infusion. No changes in platelet aggregation occurred. These results suggest that increased plasma von Willebrand factor/VIII-related antigen in diabetic patients is accompanied by an increased endothelial content of this factor.

Adenosine Diphosphate↗