The influence of stimulus parameters on the visual field indices by automated projection perimetry

The various stimulus parameters offered by two standard automated projection perimeters [Humphrey Field Analyser 630 (HFA) and Octopus 2011, namely, stimulus size and location and the interaction of adaptation level and stimulus duration, were compared in a sample of 20 patients attending a glaucoma clinic using the visual field indices mean defect (MD), loss variance (LV), short-term fluctuation (SF) and corrected loss variance (CLV). LV and SF were greater with Octopus program 32 compared with Octopus program G1 (P < 0.02). No difference in the indices was found between stimulus sizes I and III for HFA program 30-2. MD was greater for program 30-2 compared with program 32 (P < 0.002) when expressed in terms of log (L/L) whereas LV (P < 0.02) and SF (P < 0.02) were greater for program 32. All differences were considered to be negligible in the clinical sense.     

Rapidly available glucose in foods: an in vitro measurement that reflects the glycemic response

BACKGROUND: A chemically based classification of dietary carbohydrates that takes into account the likely site, rate, and extent of digestion is presented. The classification divides dietary carbohydrates into sugars, starch fractions, and nonstarch polysaccharides, and groups them into rapidly available glucose (RAG) and slowly available glucose (SAG) as to the amounts of glucose (from sugar and starch, including maltodextrins) likely to be available for rapid and slow absorption, respectively, in the human small intestine. OBJECTIVE: We hypothesize that RAG is an important food-related determinant of the glycemic response. DESIGN: The measurement of RAG, SAG, and starch fractions by an in vitro technique is described, based on the measurement by HPLC of the glucose released from a test food during timed incubation with digestive enzymes under standardized conditions. Eight healthy adult subjects consumed 8 separate test meals ranging in RAG content from 11 to 49 g. RESULTS: The correlation between glycemic response and RAG was highly significant (P < 0.0001) and a given percentage increase in RAG was associated with the same percentage increase in glycemic response. After subject variation was accounted for, RAG explained 70% of the remaining variance in glycemic response. CONCLUSIONS: We show the significance of in vitro measurements of RAG in relation to glycemic response in human studies. The simple in vitro measurement of RAG and SAG is of physiologic relevance and could serve as a tool for investigating the importance of the amount, type, and form of dietary carbohydrates for health.     

Reflex testing I: algorithm for lipid and lipoprotein measurement in coronary heart disease risk assessment

We reviewed the current literature in order to construct a reflex testing algorithm that maximizes clinical utility and cost-effectiveness of lipid and lipoprotein testing. The algorithm was based on the 2nd Report of the National Cholesterol Education Program Adult Treatment Panel guidelines for use of total cholesterol (TC), triglycerides (TG), HDL-C, and LDL-C, and published reports describing the clinical use of apolipoprotein B and lipoprotein (a). The success of this algorithm was tested in a low-risk general and a high-risk hyperlipidemic patient population. Lipid data and non-lipid risk factors were obtained from a national database and from patients seen at two lipid clinics. A total of 16 968 individuals from the National Health and Nutrition Examination Survey III database comprised the low-risk group, and 239 patients examined in the Hartford Hospital and Washington University Lipid Clinics comprised the high-risk group. We found a solid scientific base to support the NCEP guidelines and reasonable support for limited testing of apoB and Lp(a). According to the algorithm, the direct LDL-C assay was deemed unnecessary in 98% and 91% of low- and high-risk subjects, respectively, if one assumes that the Friedewald equation is adequate with TG≤4.00 g/l. With a more conservative cutoff of TG≤2.50 g/l, the algorithm canceled 92% and 81% of direct LDL tests, respectively. The algorithm also limited TG to 20 and 64%, apoB to 6 and 20%, and Lp(a) to 15 and 56%, of low- and high-risk groups, respectively. Use of a comprehensive, reflex algorithm for coronary heart disease risk assessment will substantially reduce the utilization of laboratory services without diminishing the clinical value of these tests. The algorithm will prevent the overuse of certain expensive tests (direct LDL) while promoting the limited use of underutilized tests [apoB and Lp(a)].     

Ehlers-Danlos syndrome type VII: clinical features and molecular defects

We evaluated the clinical features, molecular defects, and problems associated with the management of two patients who had type-VII Ehlers-Danlos syndrome and reviewed the cases of eighteen patients with this condition who had been reported on previously. The typical clinical features associated with this syndrome include bilateral congenital dislocation of the hip; severe generalized hypermobility of the joints; multiple dislocations of joints other than the hip; muscular hypotonia; and hyperelasticity, fragility, and a doughy texture of the skin. Collagen and DNA analyses demonstrated that both of our patients had type-VIIB Ehlers-Danlos syndrome, which is caused by heterozygous new mutations of the COL1A2 gene that encodes the proalpha2(I) chain of type-I procollagen. The obligatory GT dinucleotide at the splice donor site of intron 6 was altered in both of our patients: one patient (Case 1) had an A substitution of the G nucleotide, and the other patient (Case 2) had a C substitution of the T nucleotide. Abnormal splicing resulted in the loss of the exon 6-encoded N-telopeptide, which includes the N-proteinase cleavage site. Despite multiple operative procedures, one of our patients, who was thirty-seven years old at the time of the most recent follow-up, continued to have persistent subluxation of the right hip and osteoarthritis of the left hip. Closed reduction of the dislocated hips, regardless of the type of immobilization used, was unsuccessful in all twenty patients. The results of open reduction were improved when capsulorrhaphy was combined with iliac or femoral osteotomy, or both.     

Hemispheric asymmetries in arousal affect outcome of the intracarotid amobarbital test.

OBJECTIVE: To evaluate changes in arousal and their impact on memory performance during the intracarotid amobarbital test (IAT). METHODS: Along with memory measures, level of arousal was evaluated through clinical ratings and nonverbal self-ratings in epilepsy patients undergoing IAT before anterior temporal lobectomy. RESULTS: Irrespective of seizure focus, left-sided amobarbital injection resulted in decreased objective and subjective arousal more often than right-side injection. Impaired objective arousal was greater when the left hemisphere was injected second, because of the presumed additive effects of systemic amobarbital residual from the first injection. Decreased objective arousal was related to poorer performance on memory testing following left-hemisphere injection. CONCLUSIONS: The IAT, as practiced in most centers, is biased, so patients with right temporal lobe seizure focus are more likely to "pass" the test, whereas patients with left seizure focus are more likely to "fail" the test. The significant impact of changes in arousal on memory testing needs to be considered when using IAT results to select patients for temporal lobectomy.     

Insomnia and heart disease: a review of epidemiologic studies

Since the discovery and successful treatment of sleep apnea, researchers seem to believe that the association between sleep disturbance and coronary heart disease (CHD) has been explained. To determine whether subjective nighttime sleep complaints (trouble sleeping, trouble falling asleep, trouble staying asleep), exclusive of apnea, predicted myocardial infarction and other coronary events, a MEDLINE search was conducted for articles published between January 1976 through August 1997. Ten studies with an explicit measure of association between an insomniac complaint and CHD were identified. Reported risk ratios for various sleep complaints and CHD events ranged from 1.0 for waking too early and CHD death in an elderly North Carolina community to 8.0 for the highest versus lowest quintile of a sleep scale in Finnish men. Higher quality studies showed risk ratios of 1.47-3.90 between trouble falling asleep and coronary events after adjusting for age and various coronary risk factors (combined effect=1.7, p<0.0001). While alternative explanations such as medication use still need to be ruled out, we theorize that a subjective insomniac complaint either may be part of a larger syndrome that includes poor health and depression, or it may be related to continual stressors, reduced slow-wave sleep, and autonomic dysfunction, which increase the risk of heart problems.