Cortical circumferential profile of SPECT cerebral perfusion in Alzheimer''s disease

We developed a semiautomatic method termed “cortical circumferential profiling” for objective analysis of cerebral cortex function in emission tomographic neuroimaging studies. This method treats cortex as a continuous ring near the outer brain edge. A computer algorithm samples the cortex at 60 contiguous, equiangular locations, using 1-cm² samples. These values are plotted as a function of cortical angle to produce the cortical circumferential profile. This method was used in a study of regional cerebral perfusion in 15 patients with Alzheimer's disease and 8 elderly control subjects using N-isopropyl [I-123]-iodoamphetamine. Cortical circumferential profiling decreases variability, examines the entire cortex within slices at preselected levels above the orbital-meatal line, and facilitates intrasubject and intersubject comparisons.     

A school microepidemic of tuberculosis.

BACKGROUND: Microepidemics of tuberculosis continue to occur in countries with a low incidence of tuberculosis. METHODS AND RESULTS: A microepidemic of tuberculosis in a secondary school with 604 girls in Cork city, Ireland, in 1986 with follow up to 1990 is described. Neonatal BCG vaccination was discontinued in the city in December 1972 so most of the 342 pupils who had received BCG were aged 14 years or more. Six active cases and 75 tuberculin positive cases were found. Four of the six girls with active disease had had neonatal BCG. The 75 pupils with a positive (grade 3 or 4) Heaf test response were given chemoprophylaxis with rifampicin and isoniazid for six months; none had developed active tuberculosis four years later. The brother of the girl who was the probable index case, however, developed active tuberculosis in 1988 despite similar chemoprophylaxis. CONCLUSION: The episode highlights the fact that children who have had neonatal BCG can develop active tuberculosis as teenagers.     

Pesticide-related health problems and farmworkers

1. Migrant and seasonal farmworkers are primarily ethnic minorities who are excluded from federal laws that protect other workers. Farmworkers live and work under substandard conditions that place them at increased risk of pesticide-related illness. 2. Agriculture uses 80% of all pesticides in the U.S. Handlers who mix, load and apply pesticides as well as workers cultivating and harvesting crops sprayed with them are at risk of acute poisoning or even death from their exposures. Drift and run-off of agricultural pesticides pollute the air, soil and water, creating additional hazards to workers' families, community residents, and the environment. 3. Chronic effects, including cancer in adults and children, adverse reproductive outcomes, delayed neuropathy and neurobehavioral effects, are also associated with occupational and environmental exposure to pesticides.     

Alterations of paraoxonase and platelet-activating factor acetylhydrolase activities in patients on peritoneal dialysis.

OBJECTIVE: The more atherogenic lipid profile seen in peritoneal dialysis (PD) patients cannot fully explain the increased incidence of atherosclerosis in this population. Oxidative modification of low-density lipoproteins (LDL) is considered to play a central role in the atherogenic process, whereas high-density lipoprotein (HDL) protects LDL from oxidation. On the other hand, it has been suggested that the LDL and HDL of PD patients are more resistant to oxidation than those of control subjects, while PD-HDL equally protects LDL from oxidation compared to control-HDL. Two HDL-associated enzymes have been shown to protect both LDL and HDL from oxidation: paraoxonase (PON1) and HDL-associated platelet-activating factor acetylhydrolase (HDL-PAF-AH). Furthermore, low PON1 activity and high total plasma PAF-AH concentration, which represents mainly the LDL-associated enzyme, have been shown to be independent risk factors for coronary artery events in the general population. However, there are limited data regarding possible alterations of these enzymes in PD patients. The aim of our study was to examine the possible alterations of PON1 and PAF-AH activities in patients undergoing PD. DESIGN: A cross-sectional study. SETTING: A university medical center. PARTICIPANTS: 56 PD patients of Caucasian origin and 86 matched controls were studied. MEASUREMENTS: In all subjects, serum PON1 activity toward paraoxon (paraoxonase) and phenylacetate (arylesterase), as well as total serum and HDL-PAF-AH activities were measured; PON1 genetic polymorphisms known to influence PON1 activity (Q192R and M55L) were determined. RESULTS: The PD patients exhibited significantly increased serum PON1 (paraoxonase) and PON1 (arylesterase) activities compared to controls, regardless of the PON1 polymorphisms or the levels of HDL cholesterol. Additionally, PD patients had significantly elevated activities of total serum PAF-AH and HDL-PAF-AH, independently of the levels of LDL or HDL cholesterol. The ratio of HDL-PAF-AH/ total PAF-AH, which has recently been suggested to be a potential marker of atherogenicity, was decreased in these patients compared to controls. Moreover, no difference in the prevalence of PON1 polymorphisms between PD patients and controls was found. CONCLUSION: The elevated activities of PON1 and HDL-PAF-AH could explain the increased resistance of PD-HDL to oxidation; the higher activity of total PAF-AH and the decreased HDL-PAF-AH/ total PAF-AH ratio could contribute to the increased incidence of atherosclerosis in these patients.     

Quantitative MRI volume changes in late onset schizophrenia and Alzheimer''s disease compared to normal controls

Volumes of medial and lateral temporal lobe structures were assessed using magnetic resonance imaging (MRI) in 11 patients with late-life onset schizophrenia (LOS), 18 normal elderly controls and 12 patients with moderate cognitive impairment due to Alzheimer's disease (AD) who had no non-cognitive symptoms. While both patient groups has smaller volumes of several medial temporal regions (e.g. entorhinal cortex, left hippocampus), schizophrenics had significantly smaller anterior superior temporal gyri (STG) than normal controls, but AD patients did not. We have previously demonstrated anterior STG volume to be reduced in early life onset schizophrenia.     

Effect of fibreoptic bronchoscopy on pulmonary function.

Several studies have shown that after fibreoptic bronchoscopy there may be a deterioration in lung function but it is not known whether this is due to the premedication, the topical anaesthetic, or the obstruction produced by the bronchoscope. The effects of each part of the procedure on spirometric measurements were studied in patients with lung disease and in normal non-smokers. Measurements were made after premedication (papaveretum and atropine) in seven patients and after topical anaesthesia of the bronchial tree (340 mg lignocaine) with and without the bronchoscope in the trachea in 21 patients and 10 control subjects. Premedication had no effect. In the normal subjects lignocaine produced significant falls in FEV1, forced vital capacity (FVC), peak expiratory flow (PEF), and peak inspiratory flow (PIF), and insertion of the bronchoscope caused further falls that were also significant. In the patients, however, although anaesthesia produced significant falls in FEV1, FVC, PEF, and PIF of similar magnitude to those found in the normal subjects, there was no further important decrease when the bronchoscope was inserted. It is concluded that the major effect of bronchoscopy on lung function is due to topical lignocaine in the airways, and in patients with lung disease (excluding asthma or a central obstructing carcinoma) the insertion of the bronchoscope causes little additional obstruction.