Intercomparison of calibration procedures for 192Ir HDR sources in Brazil

The lack of well established dosimetry protocols for HDR sources is a point of great concern regarding the uniformity of procedures within a particular country and worldwide. The main objective of this paper is to report the results from ten institutions of an intercomparison of calibration procedures for 192Ir HDR sources currently in use in Brazil. The treatment irradiator of one institution was calibrated by a reference system and used by all participants with their own measuring electrometers and ionization chambers under the same experimental conditions. Two methods were used: the calibration jig and the well-type ionization chamber. Each participant was allowed to use their own method and formalism. The results of this exercise were very positive since this was the first time in Brazil that a group of users gathered to share their experience and openly discuss the physical concepts behind the calibration procedures. The results were all within +/-3.0%, except one case where -4.6% was observed and later identified as a problem with the Nk value for x-rays. Though the magnitude of the deviations found was generally acceptable considering the diversity of formalisms currently in use, a proposal is now being prepared to be adopted as a national protocol. The identification of the institutions was left out for the sake of confidentiality.     

p53 Accumulation Is a Prognostic Factor in Intestinal-Type Gastric Carcinoma but Not in the Diffuse Type

Background: The prognostic value of p53 nuclear accumulation in gastric cancer is still unclear, as shown by the discordant results still reported in the literature. In this study, we evaluated the correlation between p53 accumulation and long-term survival of patients resected for intestinal and diffuse-type gastric cancer.Methods: Eighty-three patients with carcinoma of the intestinal type and 53 patients with carcinoma of the diffuse type were included in the study. Immunohistochemical staining of the paraffin sections was performed by using monoclonal antibody DO1; cases were considered positive when nuclear immunostaining was observed in 10% or more of the tumor cells. Prognostic significance of different variables was investigated by univariate and multivariate analysis.Results: p53 positivity was found in 51.8% of intestinal-type and 50.9% of diffuse-type cases. No significant correlation between the rate of p53 overexpression and age, sex, tumor location, tumor size, depth of invasion, lymph node involvement, distant metastases, and surgical radicality was found in the two groups of patients. A statistically significant difference in survival rate was observed between p53-negative and p53-positive cases in the intestinal type (P < .05), confirmed by multivariate analysis (P < .005; relative risk = 3.09). On the contrary, no correlation with survival was found in diffuse-type cases according to p53 overexpression.Conclusions: These results suggest that the immunohistochemical detection of p53 accumulation is a useful indicator of poor prognosis in the intestinal but not in the diffuse type of gastric cancer, and are indicative of distinct molecular pathways and pattern of progression in the two histotypes.     

Physiological perspectives of therapy in bronchial hyperreactivity

Purpose

This paper reviews the literature on the aetiology and therapy of bronchial hyperreactivity to describe the underlying pathophysiology, identify patients at risk and update knowledge on new and existing therapies.

Source

Information was obtained from monograms on New Drugs for Asthma, Respiratory Medicine: recent advances, Agents and Actions Supplements, Pulmonary Pharmacology, Anesth Analg, the European Journal of Respiration and a Medline literature search.

Principal findings

Reduced airway calibre, increased bronchial contractility, altered permeability of the bronchial mucosa, humoral and cellular mediators, and dysfunctional neural regulation are critical factors for bronchial hyperreactivity, a characteristic feature of hyperreactive airways which results in bronchoconstriction after exposure to varied stimuli. Preoperative anaesthetic considerations in these patients include FEV₁ and PEFR testing to assess the severity and for optimal control of the condition. Bronchospasm causing hypoxaemia is the major intraoperative problem anticipated in these patients. Current therapeutic management of bronchoconstriction focusses on the β₂ agonists, theophylline and steroids. Besides relaxing the airway smooth muscle these agents are all capable of altering bronchial inflammatory responses. Future developments of therapy are directed towards the inflammatory components of the disease.

Conclusion

This review has presented background information on physiological mechanisms of smooth muscle contractility, pathophysiological alterations of bronchial contractility and the pharmacological basis of therapy in bronchoconstrictive disease. Information is presented to enable the prompt arrest and reversal of airway constriction, and to maintain prophylactic treatment during the perioperative period. Intraopera’tive bronchospasm is managed by adequate oxygenation and reversal of bronchoconstriction     

Detrimental effect of neoadjuvant chemotherapy in patients with stage-iiib carcinoma of the cervix - results of a randomized trial

With the objective of testing the value of neoadjuvant chemotherapy in patients with stage III B carcinoma of the cervix, we began in 1984 a randomized, phase III trial comparing BOMP chemotherapy followed by pelvic radiotherapy versus pelvic radiotherapy alone. Patients were stratified by age, extension of parametrial involvement, and lymphangiographic findings. Despite a higher complete response rate, the overall 5-year survival was significantly inferior in the combined therapy group (39% vs 23%, P=0.02). Toxicity was more pronounced in the chemoradiation arm and 4 patients developed fatal pulmonary complications. Patterns of failure were similar in both groups. The use of primary chemotherapy in advanced carcinoma of the cervix was detrimental to the patients and its use outside a protocol setting is discouraged.     

Dense cystic craniopharyngiomas

Characteristic computed tomographic (CT) findings of craniopharyngioma include calcification, contrast enhancement, and cyst formation. Sharp margins associated with a hypodense centrum usually characterize the CT appearance of a cystic tumor. The appearance of "dense" cysts in craniopharyngiomas has not been emphasized. Four cases of craniopharyngiomas with isodense to hyperdense cysts are reported. Comparative biochemical and in vitro CT analysis of cyst aspirates taken from these lesions demonstrate that high intracystic protein concentration accounts for the greater part of the hyperdensity. Various mechanisms for intracystic protein accumulation are discussed. Lesion characteristics, and not necessarily attenuation coefficients, are stressed in differentiating "dense" cystic from solid craniopharyngiomas.     

Trends in stomach carcinoma. A statistical analysis of 1204 cases

The authors report a retrospective analysis of their experience of gastric cancer. One thousand two hundred and four patients, observed between 1977 and 1994, of whom 1,094 underwent surgery, were studied. Data analysis was performed, dividing this period as follows: 1977-1982, 1983-1988, 1989-1994. The results reveal that, over time, substantial changes occurred both in tumor characteristics and surgical approach. With regards to tumor characteristics, the disease weighs heavily, even if it is less frequent than in the past (25% reduction), striking younger subjects and presenting in increasingly more aggressive forms [higher frequency of proximal (+11.4%) and diffuse forms (+18.1%), reduction of advanced forms (-11.6%) not proportional to the increase of early forms (+64.5%), as well as increase of cases with a short clinical history (+15.2%)]. In terms of surgical approach, while the use of conservative surgery was reduced during the study period, extensive procedures were more widely used, particularly in the curative treatment of advanced tumors (subtotal gastrectomies: reduction of 39.5%; total gastrectomies: increase of 106%). The increasing use of extended surgery is linked to the modifications occurred in tumor characteristics and in pre and post-operative management rather then to changes in surgical approach. It must be noted, however, that such technical advances have not yielded an improvement in survival (p = n.s.); as such, it is likely that gastric cancer has became a more aggressive disease and, therefore, has counterbalanced the benefits of early diagnosis and extended exeresis.