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P Martins

Publications and source records attributed to P Martins.

At least 19 recordsLinked to original sources
PubMed2006

First measurement of the rho spectral function in high-energy nuclear collisions.

We report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions at the CERN SPS. A significant excess of pairs is observed above the yield expected from neutral meson decays. The unprecedented sample size of 360,000 dimuons and the good mass resolution of about 2% allow us to isolate the excess by subtraction of the decay sources. The shape of the resulting mass spectrum is consistent with a dominant contribution from pi+pi- -->rho -->mu+mu- annihilation. The associated space-time averaged spectral function shows a strong broadening, but essentially no shift in mass. This may rule out theoretical models linking hadron masses directly to the chiral condensate.

Journal Article↗
PubMed2006

Diagnosis of iodinated contrast media hypersensitivity: results of a 6-year period.

BACKGROUND: Iodinated contrast media (ICM) hypersensitivity reactions represent a serious problem. Very few clinical data concerning systematic skin testing to ICM are available. OBJECTIVE: To evaluate the utility of ICM skin testing in patients with ICM hypersensitivity. MATERIAL AND METHODS: All patients referred over a 6-year period for ICM hypersensitivity past reactions were skin tested for (a) the implicated ICM, or (b) a set of ICM if they were positive for the implicated ICM or if its name was unknown. RESULTS: Forty-four patients, with a median age of 56 years, were studied (15 males, 29 females). The ICM skin tests were positive in 10 patients (23%): one had a positive skin prick test, seven an immediate positive intradermal test (IDT) and two a delayed positive IDT. Skin tests were more often positive in patients with immediate (9/32) as compared with those with non-immediate reactions (1/11). The time interval between the reaction and skin testing was shorter for those patients with an immediate ICM reaction and a positive skin test result (3 months [2.5-174.0]) as compared with those with an immediate ICM reaction and a negative skin test (48 months [6.8-159.0]), (P<0.05). Respiratory allergy was more frequent in the positive group (6/10 vs. 7/34, P<0.05). CONCLUSIONS: Skin tests with ICM are positive in a subgroup of patients with ICM hypersensitivity and may play an important role in the diagnosis of ICM allergy.

Adult↗
PubMed2001

Investigation on the co-extrudability and spheronization properties of wet masses.

In the present work, preliminary results of co-extrusion and spheronization of wet masses are reported. A ram co-extruder, manufactured in-house, was designed with two concentric single dies mounted on two concentric and independent chambers. This equipment has allowed the production of three types of extrudates (rod or solid extrudates, tubular or hollow extrudates and co-extrudates). Different wet mixtures of microcrystalline cellulose, lactose, a non-soluble in water dye and water were produced and used to feed the chambers of the ram co-extruder. Extrusions of the wet masses were carried out at different speeds of the ram (25-400 mm/min). The extrudates were evaluated according to surface characteristics (by visual inspection), force of extrusion and duration of steady-state (after recording the force applied to the ram and its displacement). Simultaneously, for each process of extrusion it was possible to assess the angles of convergence to the bottom of the chambers for both the external and internal chambers. These angles reflected the high complexity of the extrusion occurring on the external chamber in consequence of its annular geometry, in which the bisecting-line was not parallel to the axis of the extruder, by opposition to the converging angle in the internal chamber, where the bisecting-line was perfectly aligned to the axis of the extruder. Variations in the amount of water in the formulations and the speed of extrusion affected both the production and the quality of the extrudates and their ability to provide pellets. The rod extrudates were the easiest to produce and the relationships between the formulations, the processing conditions and the properties of the extrudates were immediately apparent. On the other hand, co-extrudates were more complex to characterise, although identical relationships between formulations, processing conditions and the properties of the co-extrudates were observed as for the rod extrudates. Different batches of extrudates (rod, tubular and co-extrudates) were spheronized to a maximum spheronization time of 10 min at 1000 rpm. The pellets were characterized with respect to size, size distribution, sphericity and density. Results have shown that for a larger diameter of the co-extrudates, the pellets produced were bigger ( approximately 3.38 mm) than the pellets produced from rod extrudates (1.22 mm). For longer times of spheronization, the aspect ratio and the density increased for both pellets produced from rod (0.95 and 1.46 g/cm(3)) and co-extrudates (0.90 and 1.47 g/cm(3)). The study has shown the potential of this new technology in providing a product with advantages over the traditional spheres produced by extrusion and spheronization.

Cellulose↗
PubMed2000

Structural factors affecting women's HIV risk: a life-course example.

AIDS and HIV incidence among women continues to escalate in the United States and globally. While several behavior-change interventions have shown promise in helping some women to reduce their risk of HIV infection, numerous barriers continue to prevent many at-risk women from protecting themselves effectively. This paper explores structural interventions that may influence women's HIV risk directly or indirectly. We present the life course of Bobbie, a quasi-hypothetical woman whose circumstances and behaviors are based on those of a woman with whom the first author worked in an HIV risk-reduction program. Her circumstances also reflect those of numerous women who have become infected with HIV. Bobbie's risk-enhancing life events are presented chronologically and, at each step, structural interventions are described that might have had the potential to prevent movement to the next stage. Thus, each stage represents a 'missed opportunity' for employing social and societal interventions to prevent movement along the trajectory leading to HIV infection.

Cocaine-Related Disorders↗
PubMed1998

Results of accelerated radiotherapy for supraglottic carcinoma: a Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary experience.

BACKGROUND: Carcinoma of the supraglottic larynx is a relatively common malignancy treated with either surgery, radiotherapy, or a combined approach. METHODS: The radiotherapy records of 190 patients with carcinoma of the supraglottic larynx treated at the Massachusetts General Hospital (MGH) and Massachusetts Eye and Ear Infirmary (MEEI) from 1981 to 1992 were reviewed. Of these patients, 164 were available for evaluation for local control and 169 for disease-specific survival. The patients were treated with accelerated hyperfractionated radiotherapy to 67.2-72 Gy/1.6 Gy per fraction twice a day in 6 weeks. The median follow-up was 56 months. Five-year actuarial local and regional control, relapse-free and overall survival, and voice-preservation rates were analyzed. RESULTS: For T1, T2, T3, and T4 tumors, local control rates were 96%, 86%, 76%, and 43%, respectively (p < .01), and the corresponding relapse-free survival rates were 78%, 82%, 64%, and 40% (p < .01). For the patients with N0, N1, and N2-3 disease, local control rates at the primary site were 86%, 74%, and 46%, respectively (p < .01), and the corresponding relapse-free survival rates were 79%, 53%, and 39% (p < .01). Including surgical salvage, the ultimate local control rates were 96%, 93%, 88%, and 51%, respectively (p < .01). Voice preservation rate for the entire group was 79% and for T1, T2, T3, and T4 tumors, rates were 96%, 80%, 72%, and 43%, respectively. CONCLUSIONS: Our experience with accelerated hyperfractionated radiotherapy for supraglottic carcinoma showed excellent locoregional control, relapse-free survival, and laryngeal preservation. The radiation toxicity was acceptable. The T and N stages were significant predictors of outcome, and the T4 tumors and node-positive neck disease portended a poor prognosis and therefore should be considered for protocols that include adjuvant therapies.

Carcinoma, Squamous Cell↗
PubMed1998

Effect of Tityus serrulatus scorpion toxin on serum gastrin levels in anaesthetized rat.

Scorpion toxin induces gastric secretion of acid and pepsin in rats. These effects seem to be mediated by the release of acetylcholine and histamine. However, the role of gastrin in the scorpion-toxin-induced gastric secretion is unknown. We describe the effects of the T1 fraction purified from Tityus serrulatus scorpion venom on serum and on antral tissue gastrin levels in anaesthetized rats. Gastrin levels in serum and in the antral mucosa were measured before and at intervals 5, 15, 30, 60, 90 up to 120 min after the intravenous injection of saline or the T1 fraction of scorpion venom (0.25 mg/kg) into anaesthetized rats. Antral G-cells were submitted to immunocytochemistry and electron microscopy. The data on gastrin were correlated with the gastric juice volume, and the acid and pepsin output increases induced by toxin. Scorpion toxin induced a significant increase in volume, acid output and pepsin output of gastric juice and gastrin serum levels 15-60 min after injection. Simultaneous measurements of antral gastrin levels did not show significant effects. The number of dense, intermediate and empty granules per microm(2) in the cytoplasm of antral G-cells was not significantly changed 60 min after saline or toxin injection. Scorpion toxin significantly increased serum gastrin; levels in rats.

Acetylcholine↗
PubMed1997

Child survivors of suicide: psychosocial characteristics.

OBJECTIVE: To describe psychosocial characteristics of children and young adolescents who experienced the recent suicidal death of a parent or sibling. METHOD: Sixteen families with children aged 5 years to 14 years and who experienced the suicidal death of a relative on average within the year of research assessment were recruited from the community and evaluated with standard research instruments for levels of children's psychiatric symptoms and social adjustment. RESULTS: Child survivors of suicide had a higher rate of internalizing symptoms and poorer school adjustments than a standard community sample. Twenty-five percent of the families had children who reported clinically significant symptoms of depression. Approximately 40% of the families included children who reported at least moderate symptoms of posttraumatic stress. Approximately 31% of families had at least one child who reported suicidal ideation, but no child reported a suicide attempt. Significant associations were identified between psychosocial features of the children and parental psychiatric symptoms and stressful life events. CONCLUSION: Child survivors of suicide are at risk for psychiatric symptoms and social maladjustment which require early identification and preventive intervention to minimize risk for more extensive psychosocial morbidity.

Adolescent↗
PubMed1996

Local control of T3 carcinomas after accelerated fractionation: a look at the "gap".

PURPOSE: To study the effects of midcourse treatment break or gaps related to the local control of T3 carcinoma of the oropharynx and larynx following accelerated hyperfractionated radiation therapy. METHODS AND MATERIALS: All patients were treated at the Massachusetts General Hospital from 1979 through 1994 with treatment consisting of 1.6 Gy per traction, two fractions a day for the treatment of T3 carcinoma of the oropharynx and larynx. They were entered in the head and neck data base. Their treatment dates, treatment breaks, and doses vs. local control were analyzed and compared. A p-value of 0.05 was considered statistically significant. RESULTS: A total of 162 patients were available for review. Due to the acute severe mucosal effects, most of the patients required a midcourse pause or "break" after a dose of 38.4-48 Gy before treatment could be resumed and completed. The data indicate that (a) prolongation of the treatment gap for more than 14 days, (b) total treatment course longer than 45 days, (c) total dose less than 67 Gy, and (d) male gender adversely affected local control. In spite of the gaps, the female patients with advanced carcinomas enjoyed the benefits of improved local control after the accelerated hyperfractionated radiation therapy. CONCLUSIONS: Accelerated hyperfractionation radiation therapy using 1.6 Gy per fraction/twice-a-day (b.i.d.) for a total dose of 70.4 Gy in 6 weeks is effective in achieving high local control of T3 squamous cell carcinoma of the oropharynx and larynx. The midcourse treatment gap should be as short as possible with the projected total dose and time. Should the gaps be unduly prolonged due to various circumstances, further increase in the total dose, for example, 72-75 Gy, and/or increase of the fraction sizes, for example, 1.8-2.0 Gy/f b.i.d. after the gap may be necessary to compensate for the adverse effects of the tumor regeneration from the prolonged gap.

Adolescent↗
PubMed1991

Acute gastric mucosal injury induced by toxins from Tityus serrulatus scorpion venom: a novel experimental model in the rat.

The effect of a partially purified fraction (T1) and toxin gamma purified from Tityus serrulatus scorpion venom, on gastric mucosa were investigated in anesthetized rats. The animals were injected i.v. with the T1 fraction (37.5 micrograms/100 g) or with saline and 60 min later were sacrificed and the stomachs resected. The gastric juice was measured and stereoscopic examination of the stomachs made. In animals injected with the T1 fraction there was an increase in volume, acidity and pepsin output of rat stomach. The T1 fraction also induced acute gastric injuries in the glandular mucosa, consisting of circular or linear ulcers, and punctiform lesions. Intravenous injection of 20 micrograms/100 g of a pure toxin obtained from Tityus serrulatus scorpion venom (toxin gamma) also induced similar lesions in the rat stomach. Our data indicate that the injection of T1 fraction or toxin gamma are good models to induce acute gastric ulcers in a short period of time in anesthetized rats.

Animals↗
PubMed1990

Spinal cord compression secondary to idiopathic retroperitoneal fibrosis.

Retroperitoneal fibrosis is a rare disorder in which the abnormal fibrotic tissue compresses retroperitoneal organs. In the majority of patients no obvious cause can be found, hence the name idiopathic retroperitoneal fibrosis. The process can also arise from other anatomic areas, suggesting a multifocal origin. We report a case of dorsal epidural compression in a 63-year-old patient harboring idiopathic retroperitoneal fibrosis. A magnetic resonance imaging scan revealed the precise location of the lesion. It is suggested that retroperitoneal fibrosis should be considered in the differential diagnosis of epidural spinal cord compression.

Female↗
PubMed1990

[Efficacy of the electrocardiographic diagnosis of left ventricular hypertrophy on the basis of gender].

STUDY OBJECTIVE: To determine the efficacy of electrocardiographic criteria of Left Ventricular Hypertrophy (RVL greater than 11 mm, SVE3 + RVL greater than 20 mm in females and greater than 28 mm in males, SV1 + RV6 or SV2 + RV5) in hypertensive patients according to sex. DESIGN: Retrospective study. Gold standard M mode echocardiography. SETTING: Pulido Valente Hospital Department of Cardiology (Lisbon). PATIENTS: 56 hypertensive patients (age 55.1 s.d. 11.6), 27 females and 29 males, with LVH by echocardiographic Left Ventricular Mass Index (LVMI) greater than 110 g/m2 in woman and greater than 134 g/m2 in men, respectively 10 and 19 patients. The LVMI was calculated by the formula of the American Society of Echocardiography modified by Devereux. RESULTS: The LVMI was smaller in females than in males (P = 0.007). The Cornell Criteria had the greatest efficacy in woman and the Sokolow criteria satisfactory efficacy but in man. The electrocardiogram (1 of the 4 criteria positive) had low diagnostic efficacy in woman. CONCLUSIONS: We concluded that echocardiogram is the best non-invasive diagnostic tool of Left Ventricular Hypertrophy in hypertensive females and is necessary to adjust and choose the electrocardiographic Left Ventricular Hypertrophy criteria according to sex.

Adult↗
PubMed1990

[Arrhythmia in chronic respiratory insufficiency].

Ventricular arrhythmias are frequent in chronic pulmonary disease. Hypoxemia, right ventricular enlargement, associated left ventricular dysfunction and iatrogenic factors are potential determinants of the density and complexity of these arrhythmias. Its prognostic meaning in chronic pulmonary disease and its relationship with the elevated prevalence of sudden cardiac death in these patients, are not well known. Meanwhile, the therapeutic anti-arrhythmic strategy is dominated by the correction of the etiologic factors, namely continuous oxygen therapy which decreases ventricular arrhythmia and prolongs survival. Holter 24 hours monitoring is a useful diagnostic tool in management of these patients.

Arrhythmias, Cardiac↗
PubMedDate not supplied

The relationship between headaches and sleep disturbances.

The relationship between headaches and sleep disturbances is complex and difficult to analyze. Both symptoms may have causal relations, or may be associated in the same patient with mutual reinforcements. We studied 25 patients presenting with morning or nocturnal headaches. Standard headache diagnosis and polysomnography were performed. After polysomnography, the diagnoses were reevaluated. The main headache entities were cluster, chronic paroxysmal hemicrania, migraine, tension, combined headache, and chronic substance abuse headache. For each group, headache, sleep data, and changes in diagnosis are discussed. The diagnosis was changed in 13 patients; the final diagnoses were periodic movements of sleep, fibromyalgia syndrome, and obstructive sleep apnea. The diagnoses of cluster headache and chronic paroxysmal hemicrania were not modified by polysomnography. The migraine and tension headache groups had a relative male preponderance, and the diagnosis was changed in approximately half of the patients. This was also observed in combined headaches. Patients who had chronic substance abuse headaches had mainly insomnia, which in some cases, was relieved by stopping medication. Data were also analyzed in terms of simple models linking headache and sleep disturbances. Such an approach allowed the identification of several modes of mutual interaction. In summary, morning or nocturnal headaches are frequent indicators of a sleep disturbance and their presence might justify polysomnography, and the use of simple clinical models may be useful for understanding the complex relationship between headache and sleep.

Adult↗
PubMedDate not supplied

[Intestinal necrosis in children].

The term intestinal necrosis is nothing but a clinical and pathological concept and always includes intestinal ischemia, whether or not occlusive. In a broad sense, necrotizing enterocolitis involves intestinal ischemia associated to an infectious entity. The precipitating factor for necrosis is very often difficult to identify. Necrotizing enterocolitis occurs in 90% of cases in premature neonates and is less frequent amongst other neonates, being rare in older children and adults. The authors present two clinical cases: one 7 year-old with a history of chronic neutropenia and an eleven-year old with severe cognitive impairment, dysmorphic features and behavioural disturbances. They were both admitted to hospital due to an acute abdominal condition and shock. The necrosis implied the resection of a jejunal segment in one of the cases, and a subtotal colonic resection in the other. Despite the surgery and medical support therapy, they both died due to multiple system organ failure--3 hours and fourteen days after surgery, respectively. In the second case, death occurred subsequent to a second surgery for resection of a segment of necrotic ileum. Necropsy showed an extensive necrosis of the remaining intestine in both cases. These two cases evolved as necrotizing enterocolitis of the child. In one of the cases it was possible to establish the exclusion diagnosis of neutropenic enterocolitis. The etiopathogenic mechanisms are reviewed, including thrombotic, obstructive (both extrinsic and endoluminal), inflammatory, non-occlusive ischemic and infectious. The authors stress the general therapeutic measures, the relevance of early surgical intervention and the use of subsidiary diagnostic/therapeutic technologies, such as serum and urine title of intestinal fatty acid binding protein or selective arteriography.

Child↗
PubMedDate not supplied

[Transient neutropenia in previously healthy children].

Transient neutropenia in otherwise healthy children is not unusual, the main causes being infections and drugs. The risk of developing an infectious complication in previously healthy children with transient neutropenia is low. These infections are usually superficial and caused by common bacteria. We present two cases of previously healthy children with Pseudomonas sepsis who presented with severe neutropenia, not submitted to recent hospitalization or invasive therapeutic or monitoring proceedings. We discuss the etiology of transitory neutropenia and the reasons for this severe community-acquired infection, caused by an unusual agent. The authors also mention their therapeutic attitudes for previously healthy children with transient neutropenia. They should be guided by clinical presentation and neutropenia severity.

Child↗
PubMedDate not supplied

[Idiopathic proctocolitis. Follow-up (1-13 years) of 71 patients].

Follow-up was possible in 71 of 74 patients with idiopathic proctocolitis diagnosed and/or assisted at the Department of Gastroenterology of the Centro Policínico de Almada, between 1973 and 1985. The aim of the present study was to verify the natural history of the disease and if there were statistically significant differences depending on the extension of the disease (proctitis versus colitis). Complications were present in 22 patients (31%): peri-anal (10%), local or intestinal (24%) and extra-intestinal (28%). Fifteen patients (21% of the cases) had hospital admission at least once, and 2 of them (3%) were submitted to surgery. No cases of cancer of the colon and rectum were detected and mortality was nil. Forty-one patients (58%) were assymptomatic at the last observation (45% with colitis and 75% with proctitis). There were statistically significant differences between the group of patients with ulcerative colitis and that of proctitis concerning the total number of complications (p less than 0.001), local complications (p less than 0.01), extra-intestinal complications (p less than 0.05), need for hospital admission (p less than 0.001) and absence of symptoms at the time of last observation (p less than 0.05), thus confirming a better prognosis of the disease when only the rectum is involved.

Adult↗
PubMedDate not supplied

Postoperative complications in the treatment of chagasic megaesophagus.

The postoperative complications of Chagasic megaesophagus were studied in 250 Chagasic patients referred to the Gastroenterology Clinic of Hospital das Clinicas, Federal University of Minas Gerais, Belo Horizonte, Brazil. The treatment was balloon dilatation in 45 (18.0%), myotomy and cardioplasty in 63 (25.2%), Merendino's surgery in 139 (55.6%), esophagogastroplasty in 2 (0.8%) and esophagocoloplasty in 1 (0.4%). There were 125 (50%) early and 30 (12%) late postoperative complications, and in 65 patients (26%) recurrent dysphagia was noted: nineteen (7.6%) after myotomy and cardioplasty, 9 (3.6%) after Merendino's operation and 37 (14.8%) after balloon dilatation. Eighty-five patients (34%) needed reoperations either to correct recurrent dysphagia (56 patients, 22.4%) or to treat other complications (29 patients, 11.6%). The reoperations to correct the 19 recurrences after myotomy and cardioplasty were Merendino's operation (12 patients, 4.8%), forceful dilatation (1 patient, 0.4%), forceful dilatation followed by Merendino's (2 patients, 0.8%), another myotomy (2 patients, 0.8%), myotomy followed by Merendino and balloon dilatation (1 patient, 0.4%) or esophagogastroplasty (1 patient, 0.4%). The recurrences after dilatation were treated by myotomy (15 cases, 6%), Merendino's operation (12 cases, 4.8%) and myotomy followed by Merendino's (3 cases, 1.2%). After Merendino seven reoperations (2.8%) were done: reduction of interposed loop (6 cases, 2.4%) and esophagocoloplasty (1 case, 0.4%). The time elapsed between the first operation and reoperation or dilatation varied from a few weeks to 18 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Brazil↗