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P Pons

Publications and source records attributed to P Pons.

At least 19 recordsLinked to original sources
PubMed2005

[Comparison of classic simulation and virtual simulation in breast irradiation: prospective study on 14 patients].

PURPOSE: To compare conventional 2D simulation and virtual simulation on 14 patients with breast cancer. PATIENTS AND METHODS: Patients were simulated for treatment using standard procedure. They subsequently underwent CT scan in the treatment position. The CTV was defined as breast tissue. The PTV was obtained by adding a 3D margin of 1 cm around CTV. Organs at risk (lungs and heart) were outlined. Ballistics and dose distribution obtained with the two planning methods were compared. RESULTS: With conventional simulation, 95% of CTV received 95% of the dose prescribed. Virtual simulation significantly improved dosimetric coverage of PTV without increasing irradiation volume of lung and heart. In 2D simulation, using three slices allowed optimisation by adjusting wedge angle. The five-slice plan was a much better predictor of the maximum dose regions when compared to the three-slice plan. Using entire CT data didn't give any benefit. CONCLUSION: Variations in CTV delineation and PTV definition limit interest of virtual simulation. In classic simulation, a 5 CT slice-plan can be used to optimise dose distribution.

Breast Neoplasms↗
PubMed2003

Trypanosoma cruzi infection induces microfilament depletion in human placenta syncytiotrophoblast.

Congenital Chagas disease, endemic in Latin America, is associated with premature labour, miscarriage, and placentitis. Metacyclic trypomastigotes adhere to specific receptors on the outer membrane of host cells as a prelude to intracellular invasion, causing calcium ion mobilization, rearrangement of host cell microfilaments, recruitment of lysosomes and parasite internalization. The actin cytoskeleton plays an important role in many cellular processes including the parasite invasion into mammalian cells. In order to observe if placental cytoskeleton is altered in the process of parasite invasion into placental villi, actin microfilaments were studied. Using immunohistochemical techniques, it was observed that the presence of actin in the syncytiotrophoblast was intense throughout the brush border in control placentae belonging to non-chagasic women. But after culture with the trypomastigote, this labelling disappeared, indicating that the parasite induced disassembly of the cortical actin cytoskeleton when the placenta was infected. As a control, placentae from chagasic women were studied, and no actin was found. The same results were obtained by the electron microscope. We confirmed that cortical actin rearrangements may be an early step in the Trypanosoma cruzi invasion mechanism into placental cells, in order to allow lysosomes access to the plasma membrane, and formation of the parasitophorous vacuole. The recruitment of lysosomes occurs directly beneath the invasion site, and this process is required for parasite internalization.

Actin Cytoskeleton↗
PubMed2002

[Cardiovascular risk and glucose metabolism: agreements and discrepancies between the WHO-85 and ADA-97 classifications].

UNLABELLED: AIM. To identify the differences between coronary heart disease risk in patients with altered basal glucemia (ABG), oral glucose intolerance (OGI) and type II diabetes mellitus according to the WHO-85 and ADA-97 diagnostic classifications, in an adult population at high risk for diabetes mellitus. DESIGN: Descriptive, cross-sectional, multicenter study.Setting. Seven primary health care centers in Spain.Patient. 970 persons considered the population at risk for type II diabetes mellitus. MEASURES: Participants were classified according to the criteria of the WHO-85 (normal, OGI, diabetes) and the ADA-97 system (normal, ABG, diabetes). The following variables were recorded: age, sex, smoking habit, body mass index, systolic blood pressure, diastolic blood pressure, basal glucemia, glucemia 2 h after an oral glucose tolerance test, HbA1c, microalbmuniuria, total cholesterol, HDL, LDL and triglycerides. Coronary heart disease risk was calculated with the 1998 table developed by Wilson et al. on the basis of the Framingham study. RESULTS: A total of 970 participants were studied. Mean age was 58.6 #+ 12.4 years; 453 were men (46.7%) and 517 were women (53.3%). Our analysis showed that cardiovascular disease risk factors were less frequent in normal subjects, and that their prevalence was higher in persons with diabetes (according to both WHO and ADA classifications). There were no significant differences in coronary heart disease risk or different risk factors between analogous groups in the two classification systems (normal, OGI/ABG or diabetes). Coronary heart disease risk in persons with different types of alterations in glucose metabolism was 11.3% in normal subjects, 14% in persons with OGI and 27.3% in persons with diabetes according to the WHO-85 system, and 11.4% in normal subjects, 15.7% in persons with ABG and 29.5% in persons with diabetes according to the ADA-97 system. CONCLUSIONS: The greater the alteration in carbohydrate metabolism, the greater the coexistence of risk factors and the estimated risk of coronary heart disease. There were no significant differences in the presence of cardiovascular risk factors, or in the relationship between carbohydrate metabolism and coronary heart disease risk, between analogous stages identified with one classification system or the other.

Blood Glucose↗
PubMed2001

Epidemiological relationship of human and swine Streptococcus suis isolates.

Two cases of meningitis due to Streptococcus suis in humans are reported here. A butcher and an abattoir worker were referred to a health centre in Castellón (Spain) with fever and symptoms of meningitis. After adequate treatment, a slight hipoacusia persisted as sequelae in both cases. Colonies of S. suis group R, serotype 2 and phenotype MRP+EF+ were isolated from cerebroespinal fluid. Epidemiological studies showed that both workers had in common the handling of pork meat of slaughtered healthy pigs from three closed farms. A study of the tonsils from apparently healthy, slaughtered pigs was carried out. A total of 234 tonsillar samples were obtained and 81 strains of S. suis were isolated from them. Serotype 2 appeared to be the most frequent (50.6%), and the analysis for phenotype showed a high percentage of tonsillar strains with the phenotype MRP+EF+ (35.9%). The humans and 28 tonsillar swine strains showed a similar profile (S. suis group R, serotype 2 and phenotype MRP+EF+). A total of 26 of the swine isolates were analysed by ribotyping using EcoRI. The human strains showed the same six-band hybridization pattern that shared five bands with the pattern most frequently shown by most of the tonsillar N. suis group R, serotype 2 and phenotype MRP+EF+ strains, differing only in the lightest, faintest band which was slightly less anodical in human (> or = 1.8 kb) than in swine (approximately 1.8 kb). From these results, both groups of strains, humans and porcine, showed differences; how can these differences in the pattern of ribotyping be explained if they should have the same origin? Is it possible that they have undergone an adaptation to the new host or perhaps the modification is due to other unknown causes? Further studies in this area are required in order to answer these questions.

Abattoirs↗
PubMed2000

Lymphatic filariasis in the Caribbean region: the opportunity for its elimination and certification.

In order to support the case for a certification of elimination of lymphatic filariasis (LF) in some Caribbean countries, we compared the prevalence of circulating Wuchereria bancrofti antigen in communities in Guyana, Suriname, and Trinidad. For the study, we assayed school children in six communities in Guyana, five communities in Suriname, and three communities in Trinidad for the prevalence of circulating W. bancrofti antigen, using a new immunochromatographic test for LF. We also assayed adults in these three countries, with a special focus on Blanchisseuse, Trinidad, where mass treatment for LF elimination had been carried out in 1981. The prevalences of W. bancrofti circulating antigen found in the school children populations ranged from 1.7% to 33.2% in Guyana and were 0.22% overall in Suriname and 0.0% in Trinidad. Among adults in two Guyana communities the prevalences were 16.7% and 32.1%. The results were all negative from 211 adults in communities in the north, center, and south of Trinidad, as well as from 29 adults in Suriname. The data suggest that contrary to reports of LF endemicity from the World Health Organization, LF may no longer be present in Trinidad and may be of very low prevalence in Suriname. Trinidad and Tobago and other Caribbean nations proven negative could seek to be awarded a certificate of LF elimination. In Suriname the small localized pocket of infected persons who may serve as a reservoir of LF infection could be tested and appropriately treated to achieve LF elimination. Such LF-positive countries as Guyana should access new international resources being made available for LF elimination efforts. An adequate certification program would help identify which countries should seek the new LF elimination resources.

Adult↗
PubMed2000

[Prototype of light source for photodynamic therapy in Centre of Electron Microscopy].

The Photodynamic Therapy (PDT) is a cancer treatment based on specific accumulation of a photosensitizer in the malignant tissue and its subsequent irradiation at appropriate wave lengths induce the production of oxygen singlets responsible for peroxidation of cell organelles and cell death. A prototype of a 630 nm non coherent light source designed and constructed at the Centre of Electron Microscopy of The Cordoba National University allowed a successful application of PDT, in nonmelanoma skin tumors, for the first time in this Country. A topical treatment with 20% delta aminolevulinic acid (ALA) in aqueous solution was applied in 100 lesions of actinic keratosis of 27 patients. The results obtained in this study were the following: Complete Remission (RC) 84%, Partial Remission (RP) 10%, No Response (SR) 0% and No data (SD) 6%. In the latter group are included those patients who did not return for reevaluation. The high efficiency plus the excellent cosmetic response and low aggressiveness, make the PDT the method of choice treatment of this skin pathology. In addition to be no invasive and well tolerated, the prototype of light source used in this study, was remarkably effective.

Aged↗
PubMed1997

Heterogeneity of pituitary lactotrophs: immunocytochemical identification of functional subtypes.

The existence of functional lactotroph subpopulations was confirmed in primary pituitary cell cultures of female rats submitted to estrogen treatment and stimulation with thyrotrophin releasing hormone (TRH) and angiotensin II (A-II). In cell cultures of pituitary tissue, prolactin (PRL) producing cells represent about 50% of the total cell count, most of which (90%) correspond to a typical lactotroph subpopulation characterized by large secretory granules, 500-900 nm in diameter, and well developed rough endoplasmic reticulum (RER) and Golgi complex. Few atypical lactotrophs were detected with a quiescent appearance and containing smaller secretory granules, often indistinguishable from granular content of other pituitary cells. Depletion of endogenous estrogen caused by ovariectomy (OVX) decreased the pituitary lactotroph population about 34%, with a relative increase of atypical forms (56%). Replacement therapy with benzoate estradiol (EB) to OVX rats did not reverse the proportion of typical and atypical lactotrophs gauged in control pituitary glands. The predominant lactotroph population of OVX rat was an atypical PRL producing cell which displayed a quiescent appearance compatible with a reduced secretory activity. By contrast, estrogen administration to OVX rats caused a striking development of the RER, a hypertrophy of the Golgi complex and an increased storage of mature and immature secretory granules in the majority of lactotrophs. These features are compatible with a reactivated protein synthesis. Estrogen also enhanced significantly (p < 0.05) the responsiveness of lactotrophs to A-II and the PRL secretion in both intact and OVX + EB treated rats increased by 40% and 30% respectively. By contrast, A-II did not produce any statistically significant response of lactotrophs from OVX female rats. At variance to this observation, in all models tested TRH increased significantly the PRL secretion (p < 0.05). The correlation of PRL secretion and morphology of different lactotroph subtypes authenticates the existence of a lactotroph subpopulation unresponsive to A-II in pituitary cell cultures from rats depleted of estrogen.

Angiotensin II↗
PubMed1997

Different behavior of lactotroph cell subpopulations in response to angiotensin II and thyrotrophin-releasing hormone.

1. In the present investigation we have extended the study of lactotroph subpopulations in primary pituitary cell cultures. Male rats with or without previous estrogenization followed by A-II or TRH treatments were selected as experimental models. 2. The TRH increased up to 50% the PRL released in both whole and OROX+EB rats (P < 0.05). In contrast, A-II treatment introduced no changes in PRL secretion from cell cultures derived from whole male rats but attained a significant augmentation (about 75%) of PRL secreted by ORQX+EB pituitary cells. 3. The addition of TRH and A-II to cultures of ORQX+EB-derived lactotrophs induced cytological changes compatible with a high secretory activity. In estrogen-treated rats the prevailing lactotroph subpopulation is type I. In cell cultures from control and A-II treated whole male pituitaries, the majority of lactotrophs consists of atypical subpopulations of II and III cells, with smaller secretory granules (between 150 and 300 nm in diameter). 4. Morphometry of immunostained lactotrophs performed on light microscopic preparations revealed that about 30-36% of the total cell count were lactotrophs. This percentage was fixed and did not change significantly after TRH and A-II treatments. 5. The present results confirm the presence of morphological and functional subtypes of lactotroph cells in rat pituitary. Typical PRL cell population shows the highest responsiveness to angiotensin II and TRH action. This functional heterogeneity of lactotroph subtypes may reflect an important and scarcely explored factor in the regulatory process of prolactin secretion.

Angiotensin II↗
PubMed1995

Differential proliferation of somatostatin and glucagon cells in rat pancreatic islets submitted to various stimuli.

The populations of endocrine cells in pancreatic islets are subjected to striking fluctuations in their size when subjected to sustained stimulation and/or inhibition of their secretory activity. The stimulation of a specific endocrine secretion is followed by proliferation of its producing cell, a situation that is reversed after interruption or inhibition of the stimulus. Morphometric and cytological modifications of somatostatin and glucagon producing cells (D and A cells respectively) in the islets of Langerhans have been studied by electron microscopy, immunocytochemistry and morphometry in pancreas of rats submitted to the following experimental conditions: 1) Adrenalectomized (ADX), 2) ADX treated with hydrocortisone, 3) Diabetic and 4) Cysteamine (CSH) treated rats. In addition to ultrastructural changes, the populations of A and D cells were analyzed morphometrically applying a computerized system for light microscopy of paraffin sections immunostained with peroxidase-antiperoxidase (PAP) technique. Glucagon cell population displayed striking alterations in fine structural features and in the volume density in the different experimental conditions examined. By contrast, the cytological organization and the size of somatostatin cell population were little or not affected except in the diabetic rats where the massive degeneration of beta cells grossly distorted the structure of the islets. These observations led to the conclusion that the population of D cells constitutes a stable of endocrine system, at variance to the profound modifications occurring in A cells when they are submitted to various experimental conditions that stimulate or inhibit their secretory activity.

Adrenalectomy↗
PubMed1994

Effects of successive dose increases of policosanol on the lipid profile of patients with type II hypercholesterolaemia and tolerability to treatment.

This randomized, double-blind, placebo-controlled study was conducted in 22 patients with type II primary hypercholesterolaemia to investigate the efficacy, safety and tolerability of two successive dose increases of policosanol. Patients with elevated serum low-density-lipoprotein cholesterol (LDL-C) and total cholesterol after a diet-only period received randomly, under double-blind conditions, placebo or policosanol at 5 mg once-a-day for 8 weeks. After this period, dosage was doubled to 5 mg twice-a-day for the next 8 weeks and then again doubled to 10 mg twice-a-day. It was found that the LDL-C was reduced significantly by 11.3%, 21.9% and 31.2%, while total cholesterol was also reduced significantly by 8%, 14.1% and 23% respectively in these three periods. Serum high-density-lipoprotein cholesterol (HDL-C) was increased by 7.8%, 7.2% and 8.7%, respectively, while in the placebo group a downward shift was observed. The LDL-C to HDL-C ratio was reduced significantly by 15.3%, 25.6% and 34.6%, while the total cholesterol to HDL-C ratio was also reduced significantly by 12.5%, 18.4% and 27.1%, respectively. Triglycerides and VLDL-C values did not change significantly. The reduction of LDL-C, total cholesterol, LDL-C to HDL-C, and total cholesterol to HDL-C ratios showed a dependence on the successive dose increases. Policosanol was very well tolerated. No patient discontinued the trial. No disturbances of clinical or blood biochemistry variables attributable to treatment were observed. Adverse effects reported were mild and transient, and no significant differences between groups were found.

Adult↗
PubMed1991

The role of the pneumatic antishock garment in penetrating cardiac wounds.

UNLABELLED: OBJECTIVE--To determine the impact of the pneumatic antishock garment on survival in patients with cardiac wounds. DESIGN--A retrospective review of a 6.5-year experience in a population of patients with gunshot or stab wounds to the heart (N = 70). SETTING--The city and county of Denver, Colo, where all patients were transported by paramedic ambulances to Denver General Hospital, an urban, level 1 trauma center. PATIENTS--All patients were analyzed, including those transported to the emergency department with no vital signs at the trauma scene. Only patients with definite penetrating cardiac injuries were included. METHODS--Paramedic trip sheets and emergency department, operating room, in-hospital, and autopsy records were reviewed. Demographic, clinical outcome, and treatment data were collected. A multiple logistic regression model was developed to determine which characteristics and treatment variables were independently predictive of patient outcome. The ability of each independent variable to predict outcome was determined by calculating adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS--Seventy patients (31 gunshot and 39 stab wounds) had a revised trauma score of 2.8 +/- 4.0 (mean +/- SD; range, 0-12; median, 0). Thirty-two (46%) had cardiac tamponade. Overall, 21 (30%) of the patients survived. In the logistic model, the presence of cardiac tamponade (OR, 9.1; 95% CI, 1.5 to 56.1) and a higher revised trauma score were associated with higher survival. Inflation of the pneumatic antishock garment was associated with sevenfold lower survival (adjusted OR, 0.14; 95% CI, 0.02 to 0.86); the effect was negative across all trauma score groups. CONCLUSION: --Survival in patients with penetrating cardiac wounds is highly associated with anatomic and physiologic factors, while application of the pneumatic antishock garment appears to be detrimental.

Adolescent↗
PubMed1991

[The superior mesenteric artery syndrome. Apropos of a case and review of the literature].

During laparotomy for an appendicular peritonitis, the authors found an acute mesenteric artery syndrome. Conservative treatment consisted of mobilisation of the 4th part of the duodenum with section of the suspensory muscle of Treitz, but this was not sufficient to cure the patient. Two weeks later the patient completely recovered after a duodenojejunal anastomosis. A review of the literature confirmed that surgical treatment for scoliosis and anorexia nervosa play an important role in the aetiology of this disease.

Adult↗
PubMed1989

[Ischemic heart disease. Its incidence and association with risk factors].

Cardiovascular diseases are the first cause of death in all developed countries and in many underdeveloped countries (1). In Cuba they have constituted the first cause of death in the last 20 years, with a tendency to increase, with the characteristic that this tendency is due to ischemic heart disease (IHD) (2). The frequency of IHD increases with age, but it has increased in the population under 50 years of age lately (3, 4, 5). Although the cause of atherosclerosis is unknown, in the last years an epidemiologic association has been demonstrated between the atherosclerotic disease (mainly IHD) and a series of pathologies, habits of the population, genetical, biochemical, physiological and environmental factors, which influence directly and indirectly the early development, frequency, severity evolution and prognosis of IHD and have been called coronary risk factors (CRF); at present, the disease is considered to be multifactorial and its magnitude and severity are influenced by the exposure time and the combination of CRF; it has also been demonstrated that it is decreased by the application of measures for the pressure measurements with Hg sphygmomanometer, in the population (1, 5, 6, 7, 8, 9, 10, 11). In our country, a series of studies have been made to ascertain the magnitude and characteristics of cardiovascular diseases (12-14); through these works we will know the incidence of IHD, some of its characteristics and its relation with some coronary risk factors hypercholesterolemia, arterial hypertension, (AH), diabetes mellitus, smoking habit and obesity).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗