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Biomedical subjects

M Porta

Publications and source records attributed to M Porta.

At least 37 records · Page 2Linked to original sources
PubMed1995

Diabetic retinopathy as a cause of blindness in the province of Turin, north-west Italy, in 1967-1991.

Diabetes is known to be a major contributor to blindness in industrialized countries but few data are available on the situation in Italy. As an introductory step to the implementation of permanent screening for diabetic retinopathy, a search was carried out on the causes of visual loss in the provincial territory surrounding Turin, the main city of North-West Italy. The case notes of all 4549 residents in the province who were certified blind between 1967 and 1991 were examined with regard to cause, age at onset, and year of onset of visual acuity < or = 1/20. Diabetic retinopathy was the second commonest cause of bilateral blindness (13.1% of cases), preceded by cataract (26.7%) and followed by myopia (11.1%), optic atrophy (8.9%), glaucoma (8.9%), retinitis pigmentosa (7.2%), and senile macular degeneration (4.1%). Diabetic retinopathy was the commonest eye disease among those who became blind between the ages of 50 and 70 and remained the leading cause of visual loss when the age groups 20 to 70 were pooled together. The incidence of diabetic retinopathy-related blindness did not show any trend to decrease over the 25 years investigated. It is concluded that, in spite of widespread availability of facilities for its assessment and treatment, diabetic retinopathy remains a leading cause of blindness in North-West Italy. This fully justifies the implementation of screening programmes and efficient referral chains for the early detection and prompt treatment of this complication of diabetes.

Adolescent↗
PubMed1995

Ki-ras mutations as a prognostic factor in extrahepatic bile system cancer. PANK-ras I Project Investigators.

PURPOSE: To assess the prevalence and prognostic significance of Ki-ras codon 12 mutations in extrahepatic biliary system cancer (EBSC). PATIENTS AND METHODS: Patients diagnosed with EBSC between 1980 and 1990 (N = 111) were selected from two hospitals. DNA was amplified from paraffin-embedded tissues and mutations in codon 12 of Ki-ras were detected using the artificial restriction fragment-length polymorphism (RFLP) technique. RESULTS: Tissue was available from 68.5% of patients. The prevalence of mutations was 41%. There was no association between mutations and clinical and pathologic characteristics; however, mutations in Ki-ras were associated with survival, with a median survival duration of 7.7 months for patients with wild-type Ki-ras and 1.7 months for patients with mutated tumors (hazards ratio [HR] = 1.67; P = .075). Among patients with stage I to II tumors, the chance of dying of patients with the mutation was 7.8 times higher than that of patients without the mutation (P = .087); the corresponding HR for patients with stage III to IV disease was 2.9 (P = .003). After adjusting for age, tumor site, histology, differentiation, and stage, the HR for Ki-ras mutations was 2.12 (P = .026). CONCLUSION: Ki-ras codon 12 mutations are an independent prognostic indicator in patients with EBSC. Mutation detection may be of help in the management of these patients.

Adenocarcinoma↗
PubMed1995

Pharmacoepidemiology in practice. Current status and future trends.

Pharmacoepidemiology is the application of epidemiological reasoning, methods and knowledge to the study of the uses and effects (beneficial and adverse) of drugs in human populations. As referred to by the term 'pharmacoepidemiology', the discipline now enters into its second decade, although its origins go back to the beginnings of this century. This article reviews the opinions of leading pharmacoepidemiologists on the scope and prospects for pharmacoepidemiology, and summarises the most important challenges that the discipline faces on its way towards the next century. The future of pharmacoepidemiology requires the development of research methods more able to cope with the specific problems posed by the study of drugs, notably the issue of confounding by indication and the ability to adjust accurately for severity of disease. Capacity building should also continue during the next years; training of professionals, the optimisation of computerised databases for research purposes and their joint use with more traditional epidemiological methods are major challenges. From a public health perspective, a critical task is to assess the impact that vaccines and drugs have on the overall patterns of disease in well defined populations.

Cost-Benefit Analysis↗
PubMed1995

Treatment of Cushing's disease by interstitial pituitary irradiation: short- and long-term follow-up.

Trans-sphenoidal intrasellar implantation of radioactive rods was employed to treat Cushing's disease in our Institution between 1958 and 1981. The patients were followed at regular intervals after the procedure. The aim of this work is to assess retrospectively the results, comparing the short- (1 year) and long-term (average 21.8 years) effects of this treatment. Seventy-six patients received pituitary implantation of 90Y- and one of 198Au-labelled rods, delivering a dose of 100-150,000 rad. Complete remission was obtained in a few weeks to months in 57/76 patients (5 of whom required a second implantation); 2 patients died of meningoencephalitis and 3 of cardiovascular complications associated with hypercortisolism 1 to 2 months after surgery. In 12 patients bilateral adrenalectomy or external pituitary irradiation were required to achieve remission; one of them developed Nelson's syndrome 15 years after implantation. Two were lost at follow-up. Long-term follow-up was possible in 41 patients of the initial series. Of these, 40 were cured of the disease, with hypoadrenalism developing in 25, while recurrence was observed only in the patient treated with 198Au. The incidence of hypothyroidism was 50%, and that of hypogonadism 54%. Permanent diabetes insipidus developed in 1 subject. GH deficiency resulting in retarded growth was found in the youngest patient, who had been operated at the age of 14. In conclusion, interstitial irradiation of pituitary adenomas was a safe and effective procedure for the treatment of Cushing's disease.

Adolescent↗
PubMed1995

Disagreement between hospital medical records and a structured patient interview on the type and date of the first symptom in cancers of the digestive tract.

Medical records have often been found to be less reliable than interviews to patients when data on the initial signs and symptoms of cancer, and the out-of-hospital diagnostic process are sought; in spite of this, a large body of research on "diagnostic delay" in cancer is based on clinical records. As part of a study on delay in neoplasms of the digestive tract we analyzed the agreement on the type and date of the initial symptom between hospital records and a structured personal interview. Records were abstracted for a random sample (N = 60) of 183 patients interviewed. Concordance on the date of the first symptom was deemed to exist if the difference was +/- 30 days. The Kappa index (kappa) and the overall proportion of agreement (with its corresponding 95% confidence interval) were used. Medical records and structured personal interviews were concordant on the type of the first neoplastic symptom in only 61% of cases (kappa = 0.50): 67% in esophagus cancer (kappa = 0.49), 60% in stomach cancer (kappa = 0.52), and 61% in colorectal cancer (kappa = 0.50). Records underestimated the occurrence of anorexia as first symptom and overestimated weight loss and dysphagia. Only 56% of cases were date-concordant, the agreement being lower in colorectal cancer (46%) than in esophageal (67%) and stomach cancer (75%). Records indicated the first symptom to have occurred at a later date than interviews in 33% of cases; overall, a study based on hospital records would have underestimated the symptom to diagnosis interval by 2.2 months per patient. Only 40% of cases were totally (symptom and date) concordant. Marked discrepancies may exist between the information contained in medical records and what patients report during a structured interview. The quality of medical records data on the duration and nature of cancer symptoms should be assessed before its use in etiologic and evaluative research.

Aged↗
PubMed1994

Trends in pancreatic cancer mortality in Europe, 1955-1989.

Trends in death certification rates from pancreatic cancer over the period 1955-1989 were analyzed for 25 European countries (excluding the former Soviet Union and a few smaller countries). In 1985-1989, rates for males ranged between 5.3/100,000 (age-standardized world population) in Spain and 10.3/100,000 in Hungary and Czechoslovakia. Other high-mortality areas were located in Northern Europe (Finland, Iceland, Ireland, Denmark) and Central Europe (Austria, Poland, Germany), whilst mortality was lower in Southern Europe (Portugal, Greece). Between 1955 and 1989, mortality rates increased in all the countries considered, the change ranging between 6% in Scotland and 279% in Spain; the rises were higher in the Mediterranean and Eastern European countries than in Northern Europe. Among females, Nordic countries such as Iceland, Sweden and Denmark had the highest mortality rates in 1985-1989 (over 6/100,000) and, as for males, Southern Europe (Spain, Portugal, Greece) appeared as a low-mortality area (around 3/100,000). During the 1955-1989 period, upward trends were observed in all the countries studied, with the highest increase in Greece, Italy, Bulgaria, Poland and Spain. A negative correlation was observed between the percent change in mortality rates between 1955-1959 and 1985-1989 and the rate in 1955-1959 among both males (r = -0.95, p < 0.001) and females (r = -0.81, p < 0.001). Thus, a systematic levelling of rates was observed in most countries, with the exception of the UK and some Nordic countries, whose rates were already high in the late 1950s. Tobacco smoking and dietary factors could account for some of the generalized upward trends. Improved diagnostic and death certification of the disease might also partially explain the observed figures.

Age Factors↗
PubMed1994

Diagnostic certainty and potential for misclassification in exocrine pancreatic cancer. PANKRAS I Project Investigations.

Whereas over the last decade epidemiologic studies on exocrine pancreatic cancer (EPC) continued to show a remarkable heterogeneity in diagnostic criteria applied to define caseness, the actual magnitude and consequences of misclassification remain largely unexplored. The objectives were: (1) to estimate the degree of certainty with which cases of EPC are diagnosed in the two participating hospitals (to this end a diagnostic certainty classification (DCC) was developed; (2) to test whether characteristics of cases differed by degree of diagnostic certainty; and (3) to assess what influence different definitions of case might have on risk estimates for tobacco and alcohol. All cases with a discharge diagnosis of EPC who attended at the Hospital del Mar between 1980-90 and at the Hospital Son Dureta between 1983-90 were identified through their respective tumor registries, and their clinical records were reviewed. Only 52% of 140 cases were classified in the group with a higher probability of EPC (group H). Diagnostic certainty appeared somewhat greater among women (age-adjusted odds ratio [ORa] 1.60, p = 0.18). Group H showed a higher proportion of cases with an interval from first symptom to diagnosis < or = 1 month (ORa = 2.38, p < 0.05) and the proportion of adenocarcinomas was slightly higher than in less certain cases (group L) (p = 0.051). A radical treatment was exclusively attempted in group H (p < 0.001). DCC cut-off points had a significant effect on the proportion of smokers and of alcohol drinkers, as well as on the percent of cases with pathological (cytohistological) confirmation. The proportion of cases unlikely to be of pancreatic origin in spite of having pathological confirmation was high enough to cause significant misclassification bias. Because past exposure to certain risk factors may differ among cases with different diagnostic certainty, we suggest to initially include in the case group patients who in spite of lacking pathological confirmation have strong clinical evidence supporting the diagnosis of EPC; subsequently, risk estimates should be computed across strata of diagnostic certainty to assess whether heterogeneity exists. In exocrine pancreatic cancer the impact of misclassification of disease status upon etiologic and prognostic estimates deserves at least as much attention as misclassification of exposure.

Adenocarcinoma↗
PubMed1994

Cancer survival and the duration of symptoms. An analysis of possible forms of the risk function. ISDS II Project Investigators.

The time interval between onset of symptoms and the diagnosis of cancer [symptom to diagnosis interval (SDI), or duration of symptoms] is a highly complex variable reflecting patient behaviour, the clinical course, the functioning of the health system and tumour biology. In order to assess possible forms of the risk function of SDI upon cancer survival whilst taking into account the effects of age, sex, tumour site and stage at diagnosis, 1887 symptomatic cases of lung, breast, stomach, colon, rectal, bladder cancer and lymphomas registered in the Tumour Registry of the Hospital del Mar (Barcelona) were analysed by means of survival curves and Cox proportional hazards regression. Subjects (mean age 64 years) were followed for a median length of 15 months after diagnosis (follow-up rate 93.5%). SDI showed a weak relationship with tumour stage at diagnosis and with survival: out of the seven sites studied, only in breast cancer was tumour extension at diagnosis significantly influenced by duration of symptoms, and only lung and rectal cancers showed a detectable form of the risk function of SDI upon survival; neither was linear, and for rectal cancer the relationship was complexly related with tumour stage. Hence, results show that forms of the risk function of duration of symptoms on cancer survival are specific to tumour sites, and that the interval should not be represented as a linear, continuous term. Studies analysing more complex sets of factors, processes and forms of the SDI function are needed.

Age Distribution↗
PubMed1994

Carotid pain during percutaneous angioplasty (PTA). Pathophysiology and clinical features.

Stretching of the internal carotid artery during percutaneous transluminal angioplasty (PTA) may be associated with transient neck, facial or cranial pain. We report a series of 53 cases who received PTA. Cervical pain occurred in 51% of patients, with a radiation to face and scalp in 33%. Analysis focused on: (a) description of pain intensity, quality, timing and location; (b) investigation about the role of individual and technical parameters that could influence the relative risk of pain onset during PTA; (c) comparison with other available data on pain syndromes related to the carotid artery. Intimal flapping on post-angioplasty angiograms, bradycardia during the procedure and previous history of AMI were associated with a higher risk of painful angioplasty. PTA may also serve as a tool to investigate carotid pain and may add further knowledge to the evidence available about the role of the carotid wall in the pathogenesis of facial and cranial pain.

Aged↗
PubMed1993

Raised serum apolipoprotein (a) in active diabetic retinopathy.

Progressive capillary occlusion often leads to severe retinopathy within 15-20 years of the onset of Type 1 (insulin-dependent) diabetes mellitus. Lipoprotein(a), a complex formed by apolipoprotein(a), apo B-100 and lipids, is considered an independent, genetically determined, predictor of cardiovascular disease. It may have antifibrinolytic properties in view of its similarity to plasminogen. To test the hypothesis that circulating lipoprotein(a) is associated with the process that leads to clinically active diabetic retinopathy, we measured the circulating levels of apolipoprotein(a) (which are strictly correlated with those of lipoprotein(a)) in two groups of patients with Type 1 diabetes of at least 15 years duration: 25 with active retinopathy and 27 without clinically detectable retinal lesions. Thirty-eight healthy subjects of the same age and sex served as controls. Serum apolipoprotein(a) was higher in the patients with active retinopathy (36(2-193) U/dl, geometric mean and range) than in those without clinically detectable retinal lesion (17(1-160)) and the control subjects (14(0-115)), p < 0.01 in both cases. The distribution of apolipoprotein(a) levels was skewed to the left, as expected, in the patients without clinically evident retinal lesions and the control groups, but there was a bimodal trend of distribution among those with active retinopathy. The levels of glycated haemoglobin were similar in the two groups of diabetic patients, and no significant differences were found for total and HDL cholesterol, triglycerides or apolipoproteins A1 and B between them and the control subjects. These preliminary results suggest that serum apolipoprotein(a) is elevated in patients with active retinopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The role of endothelium in the pathogenesis of diabetic microangiopathy.

Damage caused to the vessel wall by diverse mechanisms may lead to diabetic microangiopathy. Consequently, research work is more and more focusing on the pathophysiology of vascular cells, with particular emphasis on endothelium. This paper reviews the present knowledge on the alterations of small vessel endothelium in diabetes. The most important risk factors for diabetic microangiopathy are the duration of disease and the degree of metabolic control maintained throughout the years. However, genetic factors may also contribute. These are examined first, followed by the presumed roles played by increased protein glycation and the production of Advanced Glycosylation End Products, the "polyol pathway" and free radical generation. Endothelium is a widespread, extremely active organ which regulates complex physiologic functions and its structure and function are discussed in the second section of this review. The third part deals with how diabetes can affect endothelium and describes observations on endothelial metabolism in vitro as well as morphologic and functional alterations in the patients. Unfortunately, the mechanisms leading to progressive degeneration of the microcirculation and organ damage in diabetic patients remain largely unaccounted for.

Animals↗
PubMed1993

A study of the effects of human blood derivatives and individual growth factors on [3H]thymidine uptake in bovine retinal pericytes and endothelial cells.

Pericytes disappear early, selectively and specifically from retinal capillaries in diabetic microangiopathy, but little is known of their growth and turnover in health and disease. We have studied the effects of human blood derivatives and of a panel of individual growth factors on [3H]thymidine incorporation in bovine retinal pericytes and endothelial cells. Human serum and platelet-rich plasma stimulated incorporation of the nucleotide in a dose-dependent manner in both cell types, and did so more potently than platelet-free plasma. Consistent and significant stimulation of DNA synthesis in pericytes was observed with basic fibroblast growth factor (ED50 = 1.8 x 10(-13) mol/l), acidic fibroblast growth factor (7.4 x 10(-12) mol/l), insulin-like growth factor 1 (8.6 x 10(-10) mol/l), insulin (158 microU/ml) and endothelin-1 (6.1 x 10(-10) mol/l). Transforming growth factor beta 1 inhibited DNA synthesis (ID50 = 3.6 x 10(-10) mol/l) and so did heparin (1.4 x 10(-6) mol/l) and low molecular weight heparin (2.9 x 10(-6) mol/l). Retinal endothelial cells were stimulated by basic fibroblast growth factor (3.2 x 10(-13) mol/l) and acidic fibroblast growth factor (1.3 x 10(-9) mol/l), and inhibited by transforming growth factor beta 1 (1.6 x 10(-12) mol/l). Neither cell type was stimulated by platelet-derived growth factor (A + B chain heterodimer), epidermal growth factor, growth hormone, or nerve growth factor (7S complex). The characteristics and active concentrations of the above growth factors suggest that none is solely responsible for the pericyte mitogenic activity of platelets, serum or plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗