Interaction of a Motor Response, and Reaction Time and Time Estimation Tasks, on Heart Rate and Skin Conductance

The influence of motor responding and typical psychophysiological tasks on heart rate was tested by manipulating motor requirements of reaction time (RT) and time estimation (TE) tasks. Thirty-four volunteers were assigned randomly to four groups. Two groups squeezed a hand dynamometer at the start of a trial and the other two groups squeezed at the finish of the trial. The force of the squeeze was also manipulated: either 3 kg (3) or 7 kg (7). The four groups were Start 3, Start 7, Finish 3, and Finish 7. All subjects participated in the TE and RT tasks. The dependent variables were measurements of forearm flexor muscle tension, heart rate and skin conductance. It was found that the manipulations of when and with what force a person squeezed the dynamometer resulted in reliable group differences in muscle tension. The magnitude of acceleratory components of the triphasic (acceleration-deceleration-acceleration) cardiac response was amplified by tension. The magnitude of the deceleratory component seemed to depend on both muscle tension and stimulus processing. Except for the magnitude of the response-bound deceleration, RT and TE produced very similar heart rate responses, and skin conductance did not differ among groups. The data were interpreted as providing evidence that motor response acts as an amplifier for the phasic HR produced by common psychological paradigms.     

GABA-receptor activation in the globus pallidus and entopeduncular nucleus: opposite effects on reaction time performance in the cat

The possible role of GABAergic mechanisms in the control of the basal ganglia output structures, the globus pallidus (GP) and the entopeduncular nucleus (EP), was studied in cats performing a conditioned flexion movement triggered by an auditory stimulus. The effects of discrete unilateral microinjections of low doses of the GABA_A receptor agonist (muscimol 5–100 ng/ 0.5 l) and antagonist (bicuculline methiodide 25–150 ng/0.5 l) in the GP and the EP were tested on the motor performance of eight animals trained to release a lever in a simple reaction time (RT) schedule after an auditory stimulus. Control injections in neighboring structures did not induce any effect except with five- to tenfold higher doses in the closest injection sites. The dose of 20 ng muscimol injected into the ventral and medial part of the GP produced an arrest of the performance after a few unsuccessful trials (over the RT reinforcement limit of 500 ms), while muscimol injected in sites located in the lateral GP resulted in a dose-dependent lengthening in RTs, with a concomitant increase in the force change latency. In most of the subjects, the force exerted on the lever was higher after muscimol than after vehicle injection. Force change velocity was then significantly increased. In contrast, muscimol injected in the ventral and rostral region of the EP produced a decrease in RTs or a complete cessation of responding after a high number of anticipatory responses (release of the lever before the trigger stimulus). No significant changes in the force change latency could be observed while there was a non-significant tendency for the force levels to be lowered. Bicuculline injections in the EP were found to increase RTs with a concomitant increase in force change latency and a slowness of velocity, while no significant effect was observed following injections in the GP. These results suggest that a balance between GABAergic activity in the two output nuclei of the basal ganglia, the GP and the EP, is crucial for the correct initiation and execution of the conditioned motor task.     

Hepatitis E in the south west of France in individuals who have never visited an endemic area

A total of 431 consecutive patients from the Midi Pyrenees area with acute hepatitis with unknown etiology in 2001-2002 were tested for the presence of immunoglobulin G-class (IgG) anti-hepatitis E virus (HEV) antibodies. Forty-six (10.7%) had anti-HEV IgG, and the results were questionable for a further 17 (3.9%). Real time PCR based on TaqMan detection was used to identify HEV genome fragments in the serum of patients with positive or questionable anti-HEV serology. HEV RNA was found in 25.4% of cases. All amplification products were sequenced and analyzed. Phylogenetic analysis revealed that all the strains were genotype 3. In conclusion, virological and epidemiological data indicate that genotype 3 viruses are circulating in the south west part of France (Midi-Pyrenees) in patients with acute hepatitis and who have not visited recently areas in which HEV is endemic.     

Morphologic evaluation of the liver in hereditary angioedema patients on long-term treatment with androgen derivatives

17 alpha-Alkylated androgens are highly effective in preventing attacks in HAE patients. These drugs, however, seem to be implicated in the development of cholestatic jaundice, peliosis hepatis, and liver tumors. In order to assess the risk-benefit balance of the long-term therapy with androgen derivatives, a follow-up investigation was performed in 13 HAE patients. The results of this study indicate that long-term treatment (15 to 47 mo) with low doses of danazol or stanozolol does not induce significant hepatic damage detectable by laboratory tests or liver biopsy. However, the limited number of patients, although in a rather long period of observation, still suggests a careful control and the use of minimal effective doses.     

Assessment of biomaterials as components of a reciprocating dialyser during canine dialysis

A recently reported device, the sorbent suspension reciprocating dialyser (SSRD), was investigated for use as a test system for biocompatibility of dialyser components. The device is easy to assemble and operate, and allows minimal blood contact with foreign material outside of dialyser components. Its constant pressure/ variable flow rate operation allows quantification of degree of clotting of dialyser versus time. The effect of heparinization of the blood distribution gaskets (BDG) of the device on performance and dialyser lifetime was investigated. Heparin was bound to the surface of polyethylene gaskets by immersion in a solution of tridodecylmethylammonium chloride (TDMAC)-heparin complex for several hours. Gaskets were then assembled in an SSRD which was then used for experimental dialysis in dogs with AV shunts. Dialysers assembled using non-heparinized gaskets were used as controls. Blood coagulation tendency was quantified by the activated clotting time (ACT) and partial thromboplastin time (PTT), and these values correlated with the rate of clotting of the device. Heparinization of the gaskets resulted in the prevention of clotting in the dialyser until the final minutes of dialysis in all cases, in contrast to the constant decay of blood fill volume and evidence of clotting in the non-heparinized cases. However, dialyser lifetime was not significantly increased by gasket heparinization. At normal initial values of ACT (80–95 s) dialyser clotting occurred in 10–15 mia In tests with non-heparinized gaskets and systemically heparinized dogs, values obtained in the ACT test were observed to decrease during dialysis, indicating the disappearance of heparin from the blood. Both ACT and PTT tests show promise as predictors of dialyser lifetime.     

Comparison between isoprenaline infusions and bolus injections to assess β-adrenoceptor function in man,with special reference to cardiac contractility and the influence of autonomic reflexes

The present study was performed to characterize cardiovascular responses to isoprenaline and the influence of autonomic reflexes on these reponses. Nine healthy volunteers received infusions and bolus injections of isoprenaline before and after ‘autonomic blockade’ produced by intravenous atropine 0.04 mg kg^-1 and clonidine 300 μg. Heart rate, blood pressures, systolic time intervals and various echocardiographic measures of cardiac contractility were registered. No significant differences in responsiveness to isoprenaline were seen when infusions were repeated on the same day without ‘autonomic blockade’. After ‘blockade’, Δ responses at 1 nmol 1^-1 isoprenaline (infusions) were increased for diastolic blood pressure and decreased for systolic blood pressure and stroke volume. Bolus injections of 2 μg isoprenaline caused enhanced Δ responses after ‘autonomic blockade’ of diastolic blood pressure, left ventricular diameter in systole, ventricular circumferential fibre shortening, mean posterior wall velocity (V_{mean pw}), stroke volume, systemic vascular resistance, electromechanical systole (QS₂) and pre-ejection period. Systolic blood pressure decreased, in contrast to a small increase without ‘blockade’. These findings are explained by differences in haemodynamic effects of isoprenaline and by the dependence of responses on reflexes when isoprenaline is administered in different ways. When heart rate was increased by bolus doses of atropine, in the presence of β-blockade (propranolol), pre-ejection period and left ventricular diameter in systole were unaffected, and V_{mean pw} and ventricular circumferential fibre shortening showed only small increases (compared with alterations induced by isoprenaline). However, left ventricular ejection time, QS₂ and ejection time (by echocardiography), were markedly dependent on heart rate alterations. Thus, pre-ejection period, left ventricular diameter in systole V_{mean pw} and ventricular circumferential fibre shortening are parameters which can be useful in order to evaluate cardiac β-adrenoceptor sensitivity in vivo in man.     

Importance of luxury flow for critically ill patients receiving a left ventricular assist system

The presence of a significant organ dysfunction does not immediately exclude patients from consideration for treatment with a left ventricular assist system (LVAS). However, in treating morbid circulatory shock patients with multiple organ failure, it is important to know the preoperative and postoperative factor or factors related to the recovery of the damaged organ function. In this study, we retrospectively analyzed patients receiving a LVAS at our institution and tried to determine the important factors related to the survival of patients with multisystem failure. Twenty-seven patients who underwent LVAS placement at Saitama Medical School Hospital between 1993 and 2003 were included in this study. The preoperative risk factors analyzed were renal dysfunction, respiratory dysfunction, hepatic dysfunction, the existence of active infection, and the combination of all four factors. As a postoperative factor, the pump flow index (mean LVAS pump flow during the first 2 weeks after LVAS surgery divided by the body surface area) was analyzed. None of the analyzed preoperative factors could predict survival after LVAS surgery, but a pump flow index of less than 2.5 l/min/m² had a significant relationship with death after LVAS surgery. Further analysis revealed that all the patients with a pump flow index of 3.0 l/min/m² or more could overcome preoperative organ dysfunction. Congestive heart failure patients with multisystem failure need luxury pump flow for successful LVAS surgery; this factor could be especially important in device selection and postoperative management.     

Radiation therapy for pancreatic cancer: eleven year experience at the JCRT

Radiation therapy (XRT) for 41 patients with unresectable pancreatic cancer resulted in a median survival of 7.0 months. There was no difference in median survival for patients receiving external beam alone (3500 to 5600 cGy) (n = 28), intraoperative (IORT) boost plus external beam (5040 to 6750 cGy) (n = 9), or a gold-198 implant +/- external beam radiation (n = 4). A pilot study using orthovoltage IORT boost indicates no acute toxicity with doses of 1250 to 1750 cGy. Serious late damage has not been observed in any patients followed to 2 years. Local recurrence in patients treated post-operatively after "radical" surgery occurred in one of 10 (10%). This adjuvant treatment is safe and appears to improve local control rates compared to historical data, but survival is still poor. The median survival for the post-operative group is 10 months; three patients are alive without disease 8 months to 8.3 years after treatment.     

Postanesthetic malignant hyperthermia with convulsions

Journal of Anesthesia -     

Dietary Aspects to Incorporate in the Creation of a Mobile Image-Based Dietary Assessment Tool to Manage and Improve Diabetes

Diabetes is the seventh leading cause of death in United States. Dietary intake and behaviors are essential components of diabetes management. Growing evidence suggests dietary components beyond carbohydrates may critically impact glycemic control. Assessment tools on mobile platforms have the ability to capture multiple aspects of dietary behavior in real-time throughout the day to inform and improve diabetes management and insulin dosing. The objective of this narrative review was to summarize evidence related to dietary behaviors and composition to inform a mobile image-based dietary assessment tool for managing glycemic control of both diabetes types (type 1 and type 2 diabetes). This review investigated the following topics amongst those with diabetes: (1) the role of time of eating occasion on indicators of glycemic control; and (2) the role of macronutrient composition of meals on indicators of glycemic control. A search for articles published after 2000 was completed in PubMed with the following sets of keywords “diabetes/diabetes management/diabetes prevention/diabetes risk”, “dietary behavior/eating patterns/temporal/meal timing/meal frequency”, and “macronutrient composition/glycemic index”. Results showed eating behaviors and meal macronutrient composition may affect glycemic control. Specifically, breakfast skipping, late eating and frequent meal consumption might be associated with poor glycemic control while macronutrient composition and order of the meal could also affect glycemic control. These factors should be considered in designing a dietary assessment tool, which may optimize diabetes management to reduce the burden of this disease.