Pitfalls of regional cerebral blood flow analysis in cerebrovascular disease

In 20 patients with unilateral cerebrovascular disease, regional cerebral blood flow (rCBF) was measured by F-18-fluoromethane inhalation and positron emission tomography (PET). The purpose was to study various strategies of rCBF data analysis that are currently used in SPECT and PET. Methods of quantitative data analysis standardize rCBF values relative to an intraindividual reference, and thus create ratios as estimators of rCBF in the ischemic regions-of-interest (ROI). These ratios were compared as well as the absolute rCBF values in the ischemic ROI graphically and by Spearman's rank correlation coefficient (r). The results demonstrated that previously reported methods of data analysis failed to represent rCBF in the ischemic ROI; r values were 0.467, -0.406, -0.453, and 0.329, respectively (N.S.). This failure was due to a more widespread reduction of rCBF even in patients with minimal ischemic deficits. In conclusion, previously reported strategies of rCBF analysis based on intraindividual standardization should not be used in patients with cerebrovascular disease since they may produce misleading results.     

Changes in human ecology and behavior in relation to the emergence of diarrheal diseases, including cholera.

Human populations throughout the world can be found in diverse conditions. A proportion of the population of developing countries lives in deprived conditions characterized by ramshackle housing, lack of piped water and sanitation, and widespread fecal contamination of the environment. Enteric infections, particularly due to bacterial pathogenes, are readily transmitted under these circumstances. In contrast, the majority of inhabitants of industrialized countries live in a sanitary environment that generally discourages the transmission of enteric pathogenes, particularly bacteria. In both these ecologic niches, changes in human ecology and behavior are leading to the emergence of certain enteric infections. Relevant factors in developing areas include urbanization (leading to periurban slums), diminished breastfeeding, and political upheaval that results in population migrations. In industrialized areas, large-scale food production (e.g., enormous poultry farms), distribution, and retailing (e.g., fast-food chains) create opportunities where widespread and extensive outbreaks of food-borne enteric infection can ensue if a breakdown in food hygiene occurs.     

Book Reviews

Consuming Passions: Feminist Approaches to Weight Preoccupation and Eating Disorders, edited by Catrina Brown and Karin Jasper. Toronto: Second Story Press, 1993, 459 pages, $16.95 paperback.

Binge Eating: Nature, Assessment, and Treatment, by Christopher G. Fairburn & G. Terrence Wilson. New York: Guilford Press, 1993, 420 pages, $40.00     

Prolonged deterioration of ischemic brain energy metabolism and acidosis associated with hyperglycemia: human cerebral infarction studied by serial 31P NMR spectroscopy

We report on a patient with a large ischemic hemispherical stroke studied serially by 31P nuclear magnetic resonance spectroscopy. Persistent hyperglycemia was associated with prolonged acidosis in ischemic brain and failure of high-energy phosphate metabolism to recover. These in vivo human data support the concept that hyperglycemia adversely affects ischemic brain metabolism, pH, and clinical outcome.     

Further consideration of the clonal nature of Salmonella typhi: evaluation of molecular and clinical characteristics of strains from Indonesia and Peru.

We examined envelope protein profiles, chromosomal restriction endonuclease digest patterns, and immune responses to envelope proteins for collections of Salmonella typhi strains isolated in Peru and Indonesia. Only minor differences in envelope protein patterns were apparent among strains. Strains from 7 of 20 Indonesian patients had a distinct chromosomal digest pattern compared with patterns of Peruvian and other Indonesian strains. Strains with this pattern carried the gene for the j flagellar antigen (H1-j); differences in response to envelope proteins of j and d strains were noted on immunoblot analysis. Our data suggest that there are genotypic and phenotypic differences among S. typhi strains. The clinical importance of these differences remains to be fully evaluated; however, in this study it was not possible to show a clear correlation between strain characteristics and disease severity.     

The road to the discovery of the p53 protein: The Steiner Cancer Prize Award Lecture

Linxian, China has some of the highest rates of esophageal/gastric cardia cancer in the world. In 1983, esophageal balloon cytology screening was performed in 3 communes in northern Linxian. Of the participants, 10,066 with no evidence of cancer were followed prospectively for 71/2 years to evaluate the ability of the initial cytologc diagnoses to identify individuals at increased risk for developing cancer of the esophagus or gastric cardia. A total of 747 incident cases of esophageal or cardia cancer and 322 deaths due to these tumors were identified during the follow-up period and used in this analysis. The risks for esophageal or cardia cancer incidence and mortality increased in parallel with the presumed severity of the 1983 Chinese cytologic diagnoses. After adjusting for potential confounding factors, relative risks for esophageal or cardia cancer incidence, by initial cytologic diagnosis, were normal = 1.00 (reference), hyperplasia = 1.25, dysplasia 1 = 2.20, dysplasia 2 = 4.22 and near-cancer = 5.96. Our results suggest that esophageal balloon cytology, as performed and interpreted in Linxian in 1983, successfully identified individuals at increased risk for developing cancer of the esophagus or gastric cardia. © 1994 Wiley-Liss, Inc.     

Gastric ulceration caused by heater probe coagulation

A double-contrast upper gastrointestinal examination on a woman who had undergone endoscopic heater probe therapy one day earlier for multiple arteriovenous malformations revealed shallow, irregular, and linear ulcers at the sites of heater probe coagulation. Multiple shallow ulcers may therefore develop as a direct complication of heater probe therapy. Radiologists should be aware of this complication to avoid diagnostic confusion in these patients.     

MR of esthesioneuroblastoma (olfactory neuroblastoma) and appearance after craniofacial resection.

PURPOSETo analyze the MR characteristics of a series of patients with esthesioneuroblastoma and discuss the typical surgery and its postoperative MR appearance.METHODSThe MR studies of 15 patients with the pathologic diagnosis of esthesioneuroblastoma (also known as olfactory neuroblastoma) were retrospectively reviewed and correlated with CT and surgical findings. The postoperative MR studies of 10 patients who underwent craniofacial resection were also reviewed.RESULTSIn all cases the tumors arose in the superior nasal cavity and extended into the ethmoid cells. In some instances the tumors extended into the other paranasal sinuses, orbits, anterior cranial fossa, and cavernous sinus. The tumors were typically expansile and destructive in their growth patterns. Compared with brain gray matter, the tumors were hypointense on T1-weighted images and isointense to hyperintense on T2-weighted images. Nine tumors were heterogeneous and 6 were homogeneous. Contrast enhancement ranged from mild to marked. MR was useful for characterizing the various tissues and distinguishing fluid in the postoperative nasal cavity.CONCLUSIONSEsthesioneuroblastoma, although an uncommon tumor, may be suspected in lesions of the superior nasal cavity demonstrating both expansile and destructive growth properties. The MR findings are otherwise nonspecific. MR is the imaging modality of choice for depicting local tumor extension and evaluating for recurrence after craniofacial resection.     

Influence of hospital characteristics on operative death and survival of patients after major cancer surgery in Ontario.

BACKGROUND: There is a lack of information from Canadian hospitals on the role of hospital characteristics such as procedure volume and teaching status on the survival of patients who undergo major cancer resection. Therefore, we chose to study these relationships using data from patients treated in Ontario hospitals. METHODS: We used the Ontario Cancer Registry from calendar years 1990-2000 to obtain data on patients who underwent surgery for breast, colon, lung or esophageal cancer or who underwent major liver surgery related to a cancer diagnosis between 1990 and 1995 in order to assess the influence of volume of procedures and teaching status of hospitals on in-hospital death rate and long-term survival. For each disease site and before observing patient outcomes data, volume cut-off points were selected to create volume groups with similar numbers of patients. Teaching hospitals were those directly affiliated with a medical school. Logistic regression and proportional hazards models were used to consider the clustering of data at the hospital level and to assess operative death and long-term survival. We also used 4 measures to gauge the degree of procedure regionalization across the province including (1) the number of hospitals performing a procedure; (2) the percentage of patients treated in teaching hospitals; (3) the percentage of rural patients treated in higher volume procedure hospitals; and (4) median distances travelled by patients to receive care. RESULTS: The number of patients in our cohorts who underwent resection of the breast, colon, lung, esophagus or liver was 14 346, 8398, 2698, 629 and 362, respectively. Surgery in a high-volume versus a low-volume hospital did not have a statistically significant influence on the odds of operative death for patients who underwent colon, liver, lung or esophageal cancer resection. The risk of long-term death was increased in low-volume versus high-volume hospitals for patients who underwent resection of the breast (hazard ratio [HR] 1.2, 95% confidence interval [95% CI] 1.0-1.4, p < 0.05), lung (HR 1.3, 95% CI 1.1-1.6, p < 0.01) and liver (HR 1.7, 95% CI 1.0-2.7, p = 0.04). There were no significant differences in the odds of operative (in-hospital) death or risk of long-term death among patients treated in teaching compared with nonteaching hospitals. There was more regionalization of liver, lung and esophageal operations versus breast and colon operations. CONCLUSIONS: Increased hospital procedure volume correlated with improved longterm survival for patients in Ontario who underwent some, but not all, cancer resections, whereas hospital teaching status had no significant impact on patient outcomes. Across the province, further regionalization of care may help improve the quality of some cancer procedures.