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Biomedical subjects

A Puras

Publications and source records attributed to A Puras.

At least 19 recordsLinked to original sources
PubMed1997

ACE, angiotensinogen and obesity: a potential pathway leading to hypertension.

The renin-angiotensin system (RAS) plays a crucial role in the regulation of fluid volume, thereby influencing blood pressure (BP). Obesity is an important risk factor for hypertension, however the physiologic basis for this relationship has not been clarified. In a population survey we examined the potential relationship between the RAS and obesity. Based on community sampling, 449 individuals were recruited from metropolitan Kingston, Jamaica. Serum angiotensin-converting enzyme (ACE) and circulating angiotensinogen levels were measured and the associated genes were typed for previously described polymorphisms. Obese individuals (body mass index > 31) had significantly higher serum ACE and angiotensinogen levels, this relationship persisted for ACE in multivariate analyses controlling for BP, hypertension status, age, and gender. The insertion/deletion polymorphism of the ACE gene was associated with variation in the levels of ACE, but inconsistently with body mass index. Variants of the angiotensinogen gene leading to amino acid substitutions at positions 174 and 235 did not influence levels either of angiotensinogen or obesity. These data suggest that obesity may alter the levels of ACE and angiotensinogen, and provide a potential pathway through which obesity leads to elevation of BP.

Adult↗
PubMed1996

Angiotensinogen and blood pressure among blacks: findings from a community survey in Jamaica.

OBJECTIVE: To examine the association between blood pressure, angiotensinogen levels, angiotensin converting enzyme activity and polymorphisms of the angiotensinogen and angiotensin converting enzyme genes in a population-based sample. METHOD: Five hundred participants were recruited in a house-to-house survey of three communities in metropolitan areas of Kingston and St Andrew, in Jamaica. Demographic data, anthropometric and blood pressure measurements were obtained for each participant during a brief clinic visit. Circulating levels of angiotensinogen and angiotensin converting enzyme activity were measured in venous blood samples. Polymorphisms of the angiotensinogen and angiotensin converting enzyme genes were determined. RESULTS: A weak association between angiotensinogen level, angiotensin converting enzyme activity and blood pressure was identified in this population, but substantial joint effect of angiotensin converting enzyme activity and angiotensinogen level on blood pressure was apparent. Variants of the angiotensinogen gene had inconsistent effects on blood pressure and on the risk of hypertension. Angiotensinogen level and angiotensin converting enzyme activity were significantly related to several measures of obesity, including body mass index, waist circumference and skin fold thickness. CONCLUSION: The angiotensinogen and angiotensin converting enzyme genetic variants which were studied appear to have only a modest relationship with blood pressure and associated anthropometric risk factors among blacks.

Adult↗
PubMed1996

Fusocellular gonadal stromal tumour of the testis with epithelial and myoid differentiation.

We describe an unusual fusocellular gonadal stromal tumour with a benign behaviour in the left testis from a 16-year-old man. The neoplasm consisted of a non-encapsulated proliferation of irregularly arranged, fusiform cell bundles in fibrous connective tissue. The tumour cells contained a slightly infolded nucleus, some dilated rough endoplasmic reticulum cisternae, abundant filament bundles which connected to subplasmalemmal electron-dense bodies, pinocytotic vesicles and a discontinuous basal lamina. The intercellular spaces were narrow and the tumour cells were joined by desmosomes. These cells were immunoreactive for muscle actin, alpha-actinin and vimentin. Focal immunostaining for collagen type IV was observed around the cells. No immunoreactivity for keratins, desmin S-100 protein or XIIIa factor was found. The findings suggest that the tumour arose from the peritubular myoid cells.

Actins↗
PubMed1996

Polymorphisms of renin-angiotensin genes among Nigerians, Jamaicans, and African Americans.

Within the context of an international collaborative study of the evolution of hypertension in the black diaspora, we determined the allelic distribution of hypertension candidate genes for the renin-angiotensin system in three populations of African origin. The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) and the M235T and T174M variants of the angiotensinogen (AGT) gene were examined in individuals from Nigeria, Jamaica, and the United States. Large differences in the prevalence of hypertension were recorded in door-to-door surveys, ranging from 16% in Nigeria to 33% in the United States. The frequency of the D allele was similar in all groups (54%, 59%, and 63% in Nigeria, Jamaica, and the United States, respectively). The 235T allele of the AGT gene was found in 81% of US and Jamaican blacks and 91% of Nigerians; very little variation was seen for the T174M marker. Despite large differences in hypertension rates, genetic variation at the index loci among these groups was modest. Overall, the frequency of the ACE*D allele was only slightly higher than that reported for European and Japanese populations, whereas the AGT 235T allele was twice as common. Compared with blacks in the western hemisphere, Nigerians had a higher frequency of the 235T allele, which is consistent with 25% European admixture in Jamaica and the United States. The results indicate the potential for etiologic heterogeneity in genetic factors related to hypertension across ethnic groups while suggesting that environmental exposures most likely explain the gradient in risk in the comparison among black populations.

Alleles↗
PubMed1995

[Nontraumatic rhabdomyolysis: its etiology and the predictive factors of acute kidney failure].

BACKGROUND: The aim of this study was to determine the causes of non traumatic or medical rhabdomyolysis (RM) and analyze the clinical and biologic characteristics, as well as the predictive factors of acute renal failure (ARF). METHODS: Fifty-nine patients with RM admitted to the Internal Medicine Department over an 18-month period were prospectively studied. The patients were classified into etiologic groups. Anamnesis, physical exploration and general analytical studies including creatinkinase, myoglobin, aldolase, magnesium and proteinogram were performed. Urine sodium was determined in patients with ARF> RESULTS: Myalgias in 14 patients (23.7%) and a decrease in strength in 11 patients (18.6%) were the main clinical manifestations observed. As a sole cause, convulsion was the most frequent manifestation in 11 patients (18.6%) followed by muscular compression in 10 patients (16.9%). In the plurietiologic group the most frequent manifestation was muscular compression in 5 patients (16.9%) followed by alcoholism in 4 patients (6.7%). No differences were found in either the clinical manifestation or the biology of the RM among the different etiologies. Eight patients presented ARF (13.5%) with one patient requiring dialysis, and good response being observed with conservative treatment in 5 patients. On multivariant analysis the statistically significant ARF predictive factors were: age over 70 years (p = 0.003), nonketotic hyperosmolar diabetic coma (p = 0.01), previous dehydration (p = 0.001) and initial uric acid levels greater than or equal to 6 mg/dl (p = 0.002). CONCLUSIONS: The clinical expression of rhabdomyolysis was small with the most frequent manifestations being convulsions and muscular compression. The predictive factors for acute renal failure were advanced age, nonketotic hyperosmolar diabetic coma, dehydration, and hyperuricemia.

Acute Kidney Injury↗
PubMed1995

[New etiopathogenic, diagnostic and therapeutic aspects in primary pulmonary hypertension].

Primary Pulmonary Hypertension (PPH) is a rare disease of unknown aetiology that is diagnosed only when the underlying causing factors are undetermined. Usually is discovered in its late stage, when pulmonary vascular resistances are severely compromised and the pathologic changes already well developed, resulting in right heart failure and death within several years of the onset of symptoms. The data published in the last years have provided new insights into the disease knowledge. In this article currents concepts about aetiology, pathogenesis and open lung biopsy value are reviewed; clinical manifestations and diagnostic methods are described; the usefulness of medical treatment to improve quality of life in these patients, mainly anticoagulation and vasodilator therapy with high-dose nifedipine, and how lung transplantation has increasingly become an option for selected patients with PPH, is also analysed.

Anticoagulants↗
PubMed1993

[Bacteremia and multiple and recurrent skin ulcers due to Brucella melitensis. A new modality of self-induced infection].

Self-induced infections are a special form of factitious disease. They are characterized by the autoinoculation of contaminated substances or bacterial cultures which may lead to cutaneous infections, bacteremias, or arthritis by various germs. The conditions produced are difficult to diagnose and may lead to multiple operations, and sometimes mutilations or death of the patient. Herewith, a patient who, over a period of 10 months, presented 4 episodes of bacteremia and cutaneous abscess in which Brucella melitensis was isolated is described. In addition, during the second admission, the patient had factitious fever. Despite the evidence of self induced infection, the patient denied autoinoculation however, following confrontation with the facts and supportive psychotherapy the patient has not presented any further episodes after 6 months of follow up. Although the microorganisms involved in this type of disorders are various, this is the first case described in the literature of self-induced infections by Brucella melitensis.

Abscess↗
PubMed1992

A quantitative approach to the classification of hypospermatogenesis in testicular biopsies for infertility.

Absolute counts of germ cells were performed in 110 testicular biopsy specimens from 59 patients with either idiopathic infertility or varicocele and in a series of five autopsy specimens from age-matched controls. The tubular diameter, thickness of the tubular wall, and density of Leydig cells were measured. The following patterns were identified by germ-cell counts in the biopsy specimens: normal cell population, mild decrease in germ cells with normal ratio of cell types, advanced hypospermatogenesis with abnormal ratio of cell types, and Sertoli cell only. This sequence of progressive hypospermatogenesis was remarkably similar in both series. A separate category of maturation arrest was not recognized. Cell counts also correlated between right- and left-sided samples from the same patient in both series of biopsies. Reduction of tubular diameter, thickening of the tubular wall, and increase in Leydig cell density were often seen in severe stages of germ-cell impairment, although with an irregular distribution.

Adult↗
PubMed1990

[Experimental surgical model of hydrocele for the use of sclerotherapy].

Sclerosant therapy for different pathological conditions (testicular hydrocele, pneumothorax) is a little known and scantily used procedure in the clinical setting. We have developed a surgical procedure in the dog that permits reproducing adult hydrocele. This experimental model is useful for morphometric assessment of the sclerosant effects of the commonly used agents (magnesium silicate hydrate, carbolic acid, ethanolamine oleate, hydroxytetracycline chlorhydrate and quinacrine chlorhydrate). Our results show that the degree of sclerosis achieved with quinacrine and hydrotetracycline is significantly superior to that obtained with other agents.

Adult↗