Relation of virulence of pneumococcal strains for mice to the quantity of capsular polysaccharide formed in vitro

The amount of capsular polysaccharide formed in vitro by strains of pneumococcus types II, III, and VII of different virulence for mice has been measured by quantitative precipitin reactions. The quantity produced by strains of high virulence was greater for all three types than that formed by moderately virulent or avirulent strains. It is suggested that an important factor concerned in variations of virulence of pneumococci for mice is the genetic apparatus that controls the amount of SSS synthesized by the cells.     

Acquisition of M. protein by pneumococci through transformation reactions

Acquisition by pneumococcal variants of M protein and of capsular polysaccharide different from those present in the parent strain has been effected in vitro by means of transforming reactions with extracts of heterologous encapsulated pneumococci. Similar transformations have been accomplished in vivo with heat-killed vaccines as the transforming agents. Independent variation of pneumococcal capsular polysaccharide and M protein observed in nature can be brought about also in the laboratory. By means of transforming reactions, it has been demonstrated that inheritable characters of three distinct pneumococcal strains can be combined within a single strain. It is suggested that acquisition of M protein through transformation reactions occurs in cells deficient in that character.     

Experimental Measures of Ventricular Activation and Synchrony

Background: A widened QRS complex as a primary indication for cardiac resynchronization therapy (CRT) for heart failure patients has been reported to be an inconsistent indicator for dyssynchronous ventricular activation. The purpose of this study was to conduct a detailed experimental investigation of total ventricular activation time (TVAT), determine how to measure it accurately, and compare it to the commonly used measure of QRS width. In addition, we investigated a measure of electrical synchrony and determined its relationship to the duration of ventricular activation. Methods: Unipolar electrograms (EGs) were recorded from the myocardial volume using plunge needle electrodes, from the epicardial surface using “sock” electrode arrays, and from the surface of an electrolytic torso‐shaped tank. EGs were analyzed to determine a root mean square (RMS)‐based measure of ventricular activation and electrical ventricular synchrony. Results: The RMS‐based technique provided an accurate means of measuring TVAT from unipolar EGs recorded from the heart, the entire tank surface, or the precordial leads. In normal canine hearts, a quantification of ventricular electrical synchrony (VES) for normal ventricular activation showed that the ventricles activate, on average, within 3 ms of each other with the left typically activating first. Conclusion: Conclusions from this study are: (1) ventricular activation was reflected accurately by the RMS width obtained from direct cardiac measurements and from precordial leads on the tank surface and (2) VES was not strongly correlated with TVAT.     

Resistant starch — A controversial component of "dietary fibre"

Whilst “resistant starch” has both the analytical and, arguably the physiological properties of “dietary fibre”, detailed aspects of its properties have been cited as reasons for excluding it from total fibre for labelling purposes. Do these difficulties add up to a damning indictment or not? A protagonist of one side of the argument throws some new light on the properties of resistant starch, and invites readers to draw their own conclusions.     

The N400 as a function of the level of processing

In a semantic priming paradigm, the effects of different levels of processing on the N400 were assessed by changing the task demands. In the lexical decision task, subjects had to discriminate between words and nonwords and in the physical task, subjects had to discriminate between uppercase and lowercase letters. The proportion of related versus unrelated word pairs differed between conditions. A lexicality test on reaction times demonstrated that the physical task was performed nonlexically. Moreover, a semantic priming reaction time effect was obtained only in the lexical decision task. The level of processing clearly affected the event-related potentials. An N400 priming effect was only observed in the lexical decision task. In contrast, in the physical task a P300 effect was observed for either related or unrelated targets, depending on their frequency of occurrence. Taken together, the results indicate that an N400 priming effect is only evoked when the task performance induces the semantic aspects of words to become part of an episodic trace of the stimulus event.     

The effect of enprostil on duodeno-jejunal motility in man

Motor changes could be involved in the pathogenesis of diarrhoea that complicates the treatment of ulcer disease by prostaglandins. Our aim was to assess the effect of enprostil, a synthetic analogue of PGE2, on duodeno-jejunal motility. During this randomized double-blind crossover study, two manometric recordings, each lasting 20 h (12.00-08.00 hours), were carried out during dosing with 35 micrograms enprostil b.d. or placebo (eight volunteers: part 1), or during dosing with 35 or 70 micrograms enprostil b.d. (nine volunteers: part 2). Subjects were only allowed a standard dinner at 18.00 hours. During fasting, in part 1, the number of phase 3 activity patterns (PIIIs) was higher with enprostil than with placebo (P less than 0.01), without any difference in their characteristics; the overall duration of phase 1 activity was longer with enprostil than with placebo (P less than 0.01). In part 2, during fasting the number and characteristics of the PIIIs were not different, but there was a dose-related increase in PI, and decrease in PII activity. Fed motor patterns did not differ between the two doses of enprostil.     

Novel and diagnostically applicable information from optical waveform analysis of blood coagulation in disseminated intravascular coagulation

Transmittance waveform is the term applied to the optical profile generated from the process of clot formation on standard coagulation tests run on the MDA-180, a new-generation automated coagulation analyser. In patients with disseminated intravascular coagulation, a characteristically abnormal 'biphasic change' is seen on both the activated partial thromboplastin time and thrombin time waveforms. Increasing steepness of the initial slope on the waveform correlates with clinical deterioration and fulminant progression. Although the mechanism underlying the biphasic appearance remains to be elucidated, its identification provides the diagnostic laboratory with a simple, rapid and robust assay for disseminated intravascular coagulation that can help the clinician with urgent and appropriate therapeutic interventions.     

The Measurement of Opiate Dependence

The application of a dimensional concept of dependence which has received much attention over recent years in relation to alcohol, is explored here in relation to opiate dependence. A Severity of Opiate Dependence Questionnaire (SODQ) was completed by 98 subjects attending a New York drug treatment clinic. The factor structure of this questionnaire was explored and a strong first factor (39% of variance) identified which loaded on items conceptually related to a dimensional opiate dependence syndrome. Some preliminary investigation was made of issues relating to validity: SODQ correlated significantly with ‘number affixes a day’ and with a subjective measure of dependence (OSDQ), but not with quantity of heroin used or milestones in drug career. Research leads are discussed.     

The human antibody response to simultaneous injection of six specific polysaccharides of pneumococcus

A new experimental procedure for the production of arteriosclerosis in the bird is described. The subcutaneous implantation of diethylstilbestrol by means of which a sustained increase in the concentration of cholesterol, phospholipid, and neutral fat can be readily established, is shown to induce atherosclerosis of the aorta. The atherosclerosis has been compared with that artificially induced in the bird by the prolonged feeding of cholesterol and also with that occurring spontaneously. The stilbestrol-induced lesion more closely resembled the spontaneously occurring one in the bird than did that produced by cholesterol feeding. But all 3 lesions were fundamentally similar, differing only in the amounts and proportions of the various lipid constituents present. The concentrations of cholesterol in plasma of the stilbestrol-treated and cholesterol-fed birds were of the same order. Yet cholesterol constituted a greater proportion of the lipids deposited in the arterial wall of the cholesterol-fed than in that of the stilbestrol-treated birds. This finding suggests that the cholesterol content of the vascular lesion depends not only on the absolute concentration of cholesterol in plasma, but also on the proportion of cholesterol to other lipid constituents in plasma.