Effect of paced cycle length on sinus node effective refractory period before and after autonomic blockade in patients with sick syndrome

Effect of basic paced cycle length on sinus node effective refractoryperiod was studied in 22 patients with sick sinus syndrome.Sinus node effective refractory period was measured using threedifferent paced cycle lengths before and after pharmacologicautonomic blockade. Sinus node effective refractory period couldbe measured at one cycle length, at least, in 59% of the patientsbefore blockade, however, it could be measured at two or morecycle lengths in only 18% of patients because of the chaoticresponse of sinus node against premature stimuli. It could bemeasured after pharmacologic autonomic blockade in 68% of thepatients at two or more paced cycle lengths. On the other hand,the rest of the patients showed no measurable sinus node effectiverefractory period at any cycle length, for their sinus nodeeffective refractory periods were shorter than their right atrialeffective refractory periods. The comparison of sinus node effectiverefractory period at different paced cycle lengths was unsuccessfulbefore pharmacologic autonomic blockade, while the refractoryperiod was significantly prolonged as cycle length was shortenedafter blockade. We concluded that (1) sinus node effective refractoryperiod in humans is prolonged as paced cycle length decreases,(2) the autonomic reflex is the major disturbing factor in measuringsinus node effective refractory period, and pharmacologic autonomicblockade can be usefully employed to eliminate a chaotic sinusnodal response, (3) when sinus node effective refractory periodis shorter than right atrial effective refractory period, ashorter paced cycle length should be used for definite measurementof the former.     

CHILDHOOD HOUSING EXPERIENCES AND SCHOOL ATTAINMENT

The housing conditions of children in the National Child Development Study are related both to 16-year school attainment and also to progress through secondary school from 11 to 16. Children in homes which are crowded or lacking amenities, or in council homes at sixteen have relatively low scores on tests of reading and mathematics at the same age. The relationship between 16-year attainment and housing conditions is shown to be similar whether the child experienced the unsatisfactory housing at the age of 7, 11 or 16. Crowding and amenities are shown to be slightly associated with progress through the secondary school, although tenure is more strongly associated. The overall conclusions from this study are that children who have ever lived in unsatisfactory housing perform relatively poorly at school when they are 16, but no evidence emerged that there is any particular age at which housing circumstances are crucial for eventual school attainment. Consideration is also given to the importance of the wider environment in which the child lives.     

Kinetics of serum cytokines in adults undergoing peripheral blood progenitor cell transplantation

Summary. We investigated the serum cytokine levels (G-CSF, GM-CSF, IL-l/?, IL-3 and IL-6) using an ELISA in 14 patients with haematological malignancies undergoing peripheral blood progenitor cell transplantation (PBPCT). Serum G-CSF levels in all patients rose immediately after PBPCT, then gradually decreased as the neutrophil counts began to rise. No detectable serum levels of GM-CSF or IL-lp were observed, but serum levels of IL-3 rose transiently immediately following PBPCT. Serum levels of JL-6 rose transiently during a fever in four patients. These observations suggest that G-CSF and L 3 may contribute to the early haemopoietic reconstitution in PBPCT.     

Periodicity and prediction of mania onsets in biopolar I affective disorders

Abstract In studying the periodicity of mania onsets, cycle-oriented diagrams were made of the clinical course from 257 manic episodes analyzed retrospectively in 34 bipolar I manic-depressive patients for a period of about 5 years. Using these diagrams, the frequent period of mania onsets located in one-quarter of the follow-up period was pre-estimated, and the accordance ratio during a 25 month follow-up period was analyzed. The accordance ratio in all subjects was 39% (11/28) for the first episode and 35% (7/20) for the second episode. These ratios were not significantly different from the expected level (25%). The number of subjects was limited to 11 patients (10 rapid and 1 non-rapid cyclers) whose number of episodes used for the determination of the index cycle was eight or more. The accordance ratio was 64% (7/11) and 60% (6/10) for the first and second episodes, respectively. Their levels were significantly higher than those expected. Periodicity of mania onsets existed at least in rapid cyclers with abundant past data.     

SPINAL CORD VASCULARITY. A HISTOPATHOLOGICAL AND ANGIOGRAPHIC STUDY OF THE EFFECTS OF THORACIC-LUMBAR AORTIC MOBILIZATION IN THE RAT

A clinical, histopathological and microangiographical study has been performed in eighty-three rats subjected to regional mobilization of the thoracic-lumbar aorta. Paralysis or paresis of the hindlimbs was observed in about one-fourth of the animals, predominantly in those subjected to an extensive mobilization of the aorta. A staged mobilization of the thoracic-lumbar aorta separated by an interval of 1 week not only minimized the incidence of neurological complications but the severity as well. The topographical distribution of the histopathological changes varied considerably both in the longitudinal and the transverse plane of the spinal cord in different experimental groups as well as individually in the same group of animals. Typical lesions were dorsal spinal cord infarction and arterial watershed lesions at the base of the dorsal horn, in addition to circumscribed necroses of the white matter corresponding fairly well to venous watershed zones. Microangiographically, the preservation of the caudal cord in cases with massive infarction of the thoracic cord, is believed to be due to a number of intramedullary arterial anastomoses. Usually a sufficient collateral blood supply to the spinal cord is readily available even in the case of comparatively extensive aortic mobilization. Enlargement and tortuosity of the spinal cord arteries and the intersegmental anastomoses immediately outside the spinal canal suggest that these vessels are the most important sources in the re-establishment of the collateral circulation.     

SMOKING IN PREGNANCY AND SUBSEQUENT DEVELOPMENT OF THE CHILD

Summary Data from the National Child Development Study have been used to examine the relationship between mother's smoking during pregnancy and neonatal mortality, birthweight and the subsequent development of the child to the age of 11. In this paper analyses are reported which extend this work to examine development by the age of 16. After allowing for a wide range of related background factors, it is found that mothers smoking during pregnancy continues to be related to the child's reading and mathematics attainment. For boys, but not girls, there is an association with height. An inconsistent relationship is found with the child's history of asthma and wheezy bronchitis. Some doubts about the direct causality of such relationships are discussed.     

EFFECT OF FUSARIC ACID (A DOPAMINE β-HYDROXYLASE INHIBITOR) ON PHAEOCHROMOCYTOMA

Fusaric acid, an inhibitor of dopamine beta-hydroxylase, which converts dopamine to noradrenaline, lowered the blood pressure and induced a subjective improvement in patients with phaeochromocytoma. These effects may be due either to an impairment of catecholamine biosynthesis or to a direct action on the blood vessels. The use of this drug in the treatment of patients with inoperable malignant phaeochromocytoma or neuroblastoma may improve symptoms and prolong survival.     

AFFINITY CHROMATOGRAPHIC PURIFICATION OF PAPAIN A Reinvestigation

A reinvestigation of the affinity chromatographic method of purifying papain has been carried out. It has been reported that papain could be purified by taking advantage of the affinity of the enzyme for the insolubilized peptide inhibitor, agarose-Gly-Gly-Tyr(Bz)-Arg. Using pure tetrapeptide obtained commercially and standard coupling procedures, a significant purification of papain could not be achieved. Both active and nonactivatible enzyme bound to a column prepared in this manner were eluted together by the use of deionized water. An affinity medium with properties similar to those reported by Blumberg et al. was obtained by removal of the benzyl group on tyrosine prior to coupling with agarose. The deprotected tetrapeptide was also synthesized by an independent route and inhibition constants for the binding of the protected and deprotected tetrapeptide to papain were determined in kinetic experiments.