QT interval dispersion in healthy subjects and survivors of sudden cardiac death: circadian variation in a twenty-four-hour assessment

Twenty-four-hour acquisition of QT dispersion (QTd) from the Holter and the circadian variation of QTd were evaluated in 20 survivors of sudden cardiac death (SCD), in 20 healthy subjects, and in 14 control patients without a history of cardiac arrest who were age, sex, diagnosis and therapy matched to 14 SCD patients. Computer-assisted QT measurements were performed on 24-hour Holter recordings; each recording was divided into 288 5-minute segments and templates representing the average QRST were generated. QTd was calculated as the difference between QT intervals in leads V1 and V5 for each template on Holter. The 24-hour mean QTd was significantly greater in SCD patients (40 +/- 28 ms) than in healthy subjects (20 +/- 10 ms) and control patients (15 +/- 5 ms) (p <0.05). There was a circadian variation in QTd with greater values at night (0 to 6 A.M.) than at daytime (10 A.M. to 4 P.M.) in healthy subjects (25 +/- 13 vs 15 +/- 8 ms, p <0.001) and control patients (18 +/- 10 vs 12 +/- 4 ms p <0.05), whereas in SCD patients there was no significant difference between night and day values (45 +/- 31 vs 37 +/- 28 ms, p = NS). It is concluded that QTd measured by Holter was greater in SCD patients than in healthy subjects and matched control patients during the entire day. QTd has a clear circadian variation in normal subjects, whereas this variation is blunted in SCD patients. QTd measured on Holter differentiates survivors of cardiac arrest and may be a useful tool for risk stratification.     

A critical period in the sensitivity of basal forebrain cholinergic neurones to NGF deprivation

OBJECTIVE: We undertook this study to investigate functional MR imaging as a new clinical method for determining hemispheric language dominance. Seven patients undergoing surgical evaluation for chronic intractable epilepsy were studied. Intracarotid amobarbital injection was also performed and the findings compared with the functional MR imaging results. CONCLUSION: Functional MR imaging studies enabled localization of the frontal and temporal lobe language cortices. The results of functional MR imaging and intracarotid amobarbital testing of hemispheric language dominance agreed in all seven patients, including two right-handed patients with right-hemisphere language dominance. These preliminary results show that functional MR imaging is an accurate noninvasive method of determining language dominance that may replace the amobarbital test for some purposes if confirmed by additional research.     

Whatever happened to scholarly discourse? A reply to B. F. Skinner.

Comments that B. F. Skinner (see record 1988-00027-001) has presented an egregiously inaccurate characterization of humanistic psychology. The authors note that Skinnerian radical behaviorism emphasizes behavior, science, and technology, while humanistic psychologies emphasize human beings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A theoretical analysis of illusory contour formation in stereopsis.

A theoretical analysis of how illusory contours are formed in untextured stereograms is presented that focuses on the role of contour junctions in initiating surface interpolation processes. This theory asserts that the matching geometry of stereoscopic junctions-–that is, the pattern of matchable and unmatchable features present at the intersection of binocularly viewed contours--initiates processes of illusory contour formation (modal completion) and the connection of partially occluded objects (amodal completion). The matching geometry of 3 forms of stereoscopic junctions that elicit percepts of illusory surfaces is derived under the assumption that only horizontal disparities are matched. This analysis reveals the presence of 2 distinct kinds of monocular features generated by binocular viewing. Experiments and demonstrations are presented that reveal the role these monocular features play in modal and amodal completion in stereopsis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimation of maprotiline in serum by gas-chromatography, with use of a nitrogen-specific detector

We describe a gas-chromatographic procedure for estimating therapeutic concentrations of maprotiline, a new tetracyclic antidepressant, in serum by use of a nitrogen-specific detector. Desmethyldoxepin, a secondary amine similar in structure to maprotiline, is added as a mass internal standard to the specimen before extraction, to obviate the need for accurate measurements of volumes during extraction and analysis. Both maprotiline and the internal standard are converted to acetyl derivatives, to avoid the adsorption of secondary amines on the column. A highly selective liquid phase is used, which allows a very good separation of desmethyldoxepin, maprotiline, desmethylmaprotiline, and the interferences from serum and reagents.     

Freezing temperature of finger skin

In 45 subjects, 154 frostnips of the finger were induced by cooling in air at -15 degrees C with various wind speeds. The mean supercooled skin temperature at which frostnip appeared was -9.4 degrees C. The mean skin temperature rise due to heat of fusion at ice crystallization was 5.3 degrees C. The skin temperature rose to what was termed the apparent freezing point. The relation of this point to the supercooled skin temperature was analyzed for the three wind speeds used. An apparent freezing point for a condition of no supercooling was calculated, estimating the highest temperature at which skin freezes at a given wind speed. The validity of the obtained differences in apparent freezing point was tested by an analysis of covariance. Although not statistically significant, the data suggest that the apparent freezing point with no supercooling decreases with increasing wind velocity. The highest calculated apparent freezing point at -15 degrees C and 6.8 m/s was 1.2 degrees C lower than the true freezing point for skin previously determined in brine, which is a statistically significant difference.     

Erucamide

Erucamide has, to a great extent, replaced the use of oleamide because of its higher mp and higher heat resistance. These properties are desirable because of the higher operating temperatures of newer polymers. Various derivatives are discussed, such as N-stearyl erucamide, which has a still higher mp and greater thermal stability. This type of product is used principally as a slip additive, an antiblock agent, and for paper-coating compositions and water-proofing. Erucamide and some of its derivatives are approved for use in polymers at low concentration levels. At these levels, the material is effective without adversely affecting other physical characteristics of the polymer. A summary of the literature is presented, including a review of some of the patents. Size of the market also is discussed. One of 12 papers presented in the symposium “Novel Uses of Agricultural Oils” at the AOCS Spring Meeting, New Orleans, April 1973.     

Consent in the 90's

Patients consent to surgical procedures is a universal issue in medical law. The legal position in Australia, because it falls somewhere between the North American doctrine of "informed consent", and the Bolam test in the United Kingdom, will be of interest to all clinicians and legal practitioners dealing with these issues. The High Court of Australia's decision in Rogers v Whitaker (1992) 109 ALR 625 is now the leading decision regarding of consent to surgical procedures in Australia. The author draws a thumbnail sketch of the law in Australia, and discusses some loopholes in the legal structure established by the Australian High Court. The author supports the view taken by the High Court of Australia, and provides some material to contest the allegation made by clinicians that lawyers in Australia are in some way responsible to "opening the floodgates" for an increase in legal claims by patients.