Estimation of human myocardial mass with MR imaging

The accuracy and reproducibility of magnetic resonance (MR) imaging in the determination of left ventricular mass in humans was investigated. Left ventricular wall volume was measured from ten short-axis, end-diastolic MR images that spanned the left ventricle. Mass was estimated on the basis of average left ventricular wall volume and an assumed myocardial density. To establish the accuracy of the technique, the authors imaged ten cadaver hearts and compared true left ventricular weight with the mass estimate based on MR imaging findings. In vivo determination of left ventricular mass was evaluated in 40 subjects, with resultant calculated masses of 156.4-319.3 g. Intra- and interobserver variabilities of the technique were analyzed in ten subjects. Both the intra- (r = .96, standard error of estimate [SEE] = 11.1 g) and interobserver variabilities (r = .91, SEE = 17.8 g) were excellent. Eight subjects were imaged on two separate occasions to evaluate reproducibility of the technique and confidence limits for a given measurement. For these eight, there was good correlation between the two estimates (r = .93, SEE = 21 g). The authors conclude that MR imaging yields highly accurate and reproducible estimates of left ventricular mass in humans in vivo.     

The functional role of acute phase plasma proteinase inhibitors

Human plasma contains an array of proteinase inhibitors which are utilized in the regulation of a host of biological activities, including coagulation, fibrinolysis, connective tissue turnover, and complement activation. The concentration of several of these inhibitors increase at varying rates in the acute phase state while others remain constant or actually decrease. Increases are presumably an attempt to retain rigid control over certain critical reactions, while decreases are probably due to inhibitor turnover either through consumption during complex formation or inactivation by other endogenous proteinases. Virtually all of these latter reactions take place in a reactive site loop which is an exposed region present in at least eight related serine proteinase inhibitors (Serpins) in plasma. Complex formation and inhibitor inactivation presumably act as signals for inhibitor production and turnover in the acute phase state. However, exactly how this initial stimulus for increased protein synthesis is manifested at the protein level remains to be established.     

Prognosis of chronic obstructive pulmonary disease after acute respiratory failure

We followed the course of 53 patients (male 38, female 15 and average age 66 +/- 10) with chronic obstructive pulmonary disease hospitalized in our intensive care unit due to acute episode of respiratory failure. Etiologies of acute respiratory failure, patient's clinical data and arterial blood gases analysis were recorded. Most of the results showed no significant difference between the initial survival and the non-survival group. Low hematocrit. hypoalbulinemia and severe hypoxemia were found in the dead group but relative hypercapnea in the survival group was noted. Infection was the most common cause of acute respiratory failure and following by congestive heart failure, pneumothorax and asphyxia. Intubation and mechanical ventilator were needed in all patients except 3 cases to whom only conservative treatment was given. Hospital mortality was 50.9 percent (27/53) and most of the cases (22/53) died in the intensive care unit. Twenty six cases (49.1%) were discharged from the hospital and follow-up was continued for at least two years. Fifteen patients died during two year follow-up and except for one suicide case all died of repeated respiratory failure. The two year survival was only 20.8 percent (11/53). The prognosis of patients with chronic obstructive pulmonary disease following an episode of acute respiratory failure is poor.     

Telephone consultations at the emergency service, Copenhagen County: analysis of doctor-patient communication patterns

BACKGROUND: Experience from 10 telephone consultation courses in 1995, arranged for the emergency service in Copenhagen County, has demonstrated that this type of communication requires specific skills on the doctor's part, especially because the doctor cannot see the patient, patients are frequently in some sort of 'crisis' and, on the basis of limited information, the doctor in charge has to arrive at a prompt diagnosis in order to advise or refer the patient. METHODS: Using video-supervised role-play we compiled and organized the experience of 152 doctors. During the courses we developed principles to help doctors to optimize the information output and reliability of their telephone consultations. The doctors playing their 'patients" role had the opportunity to experience the situation from the patient's point of view and were later able to give the 'doctor' valuable feed- back. RESULTS AND CONCLUSIONS: This 'experimental consultation procedure' constitutes a new research method, at the interface between educational and traditional scientific research. The process in question is a feed-back one, in which findings can be applied and tested instantly, or with little delay, to produce new results. These can be put to use in practical clinical work and tested in new 'laboratory experiments'.      

Modulation of cytosolic free calcium concentration by α1-adrenoceptors in rat atrial cells

Summary The effects of ₁-adrenoceptor stimulation by phenylephrine (PE) and -adrenoceptor stimulation by isoprenaline (ISO) on Ca²⁺ current (I_Ca) and free intracellular Ca²⁺ concentration ([Ca²⁺]_i) were studied in isolated atrial myocytes from rat hearts. PE did not significantly affect the magnitude of I_Ca, whereas large increases of peak I_Ca were observed in response to ISO. In electrically driven cells, PE evoked a concentration-dependent, gradual increase in diastolic [Ca²⁺]_i and, initially, an increase in the height of peak [Ca²⁺]_i transients. When the diastolic [Ca²⁺]_i was increased to a greater extent, the amplitude of [Ca²⁺]_i transients was decreased. Simultaneous measurements of [Ca²⁺]_i and membrane potential showed that the increase in diastolic [Ca²⁺]_i was associated with a depolarization of the membrane, and the greater amplitude of [Ca²⁺]_i transients with a prolongation of the action potential (AP). The PE-induced increase in diastolic [Ca²⁺]_i was eliminated when the cells were voltage-clamped at the original resting membrane potential (RP); under these conditions, an increase in [Ca²⁺]_i transients was observed in response to PE. ISO usually caused larger increases in the amplitude of [Ca²⁺]_i transients with only minor changes in diastolic [Ca²⁺]_i. These results suggest that PE and ISO increase the amplitude of [Ca²⁺]_i transients in rat atrium in different ways. The increase in [Ca²⁺]_i transients in response to -adrenoceptor stimulation is commonly thought to be mediated by a greater conductance of voltage-dependent Ca²⁺ channels causing a greater Ca²⁺ influx and a release of more Ca²⁺ from the sarcoplasmic reticulum during the AP. The increase in diastolic [Ca²⁺]_i in response to PE is probably a consequence of the depolarization of the membrane, possibly involving the voltage-dependent Na⁺-Ca²⁺ exchange mechanism. The increase in the amplitude of the [Ca²⁺]_i transients in response to PE may be ascribed both to the initial increase in diastolic [Ca²⁺]_i and the prolongation of the AP. Send offprint requests to H. Nawrath at the above address     

Non-invasive Assessment of Swallowing and Respiration Coordination for the OSA Patient

The objectives of this study are to investigate swallowing and its coordination with respiration in patients with obstructive sleep apnea (OSA). This is a prospective cohort study conducted in a tertiary referred Medical Center. A non-invasive method of assessing swallowing was used to detect the oropharyngeal swallowing parameters and the coordination with respiration during swallowing. The system used to assess swallowing detected: (1) movement of the larynx using a force-sensing resistor; (2) submental muscle activity using surface electromyography; and (3) coordination with respiration by measuring nasal airflow. Five sizes of water boluses (maximum 20 mL) were swallowed three times, and the data recorded and analyzed for each participant. Thirty-nine normal controls and 35 patients with OSA who fulfilled the inclusion criteria were recruited. The oropharyngeal swallowing parameters of the patients differed from the controls, including longer total excursion duration and shorter duration of submental muscles contraction. A longer swallowing respiratory pause (SRP), temporary coordination with respiration during swallowing, was demonstrated in the patients compared with the controls. The frequency of non-expiratory/expiratory pre- and postswallowing respiratory phase patterns of the patients was similar with the controls. There was significantly more piecemeal deglutition in OSA patients when clumping 10- and 20-mL water boluses swallowing together (p = 0.048). Oropharyngeal swallowing and coordination with respiration affected patients with OSA, and it could be detected using a non-invasive method. The results of this study may serve as a baseline for further research and help advance research methods in obstructive sleep apnea swallowing studies.     

How to reduce sitting time? A review of behaviour change strategies used in sedentary behaviour reduction interventions among adults

Sedentary behaviour – i.e., low energy-expending waking behaviour while seated or lying down – is a health risk factor, even when controlling for physical activity. This review sought to describe the behaviour change strategies used within interventions that have sought to reduce sedentary behaviour in adults. Studies were identified through existing literature reviews, a systematic database search, and hand-searches of eligible papers. Interventions were categorised as ‘very promising’, ‘quite promising’, or ‘non-promising’ according to observed behaviour changes. Intervention functions and behaviour change techniques were compared across promising and non-promising interventions. Twenty-six eligible studies reported thirty-eight interventions, of which twenty (53%) were worksite-based. Fifteen interventions (39%) were very promising, eight quite promising (21%), and fifteen non-promising (39%). Very or quite promising interventions tended to have targeted sedentary behaviour instead of physical activity. Interventions based on environmental restructuring, persuasion, or education were most promising. Self-monitoring, problem solving, and restructuring the social or physical environment were particularly promising behaviour change techniques. Future sedentary reduction interventions might most fruitfully incorporate environmental modification and self-regulatory skills training. The evidence base is, however, weakened by low-quality evaluation methods; more RCTs, employing no-treatment control groups, and collecting objective data are needed.     

Wolfram (DIDMOAD) syndrome: report of two patients

We report a girl with Wolfram syndrome who presented with juvenile-onset diabetes mellitus when she was 4 3/12 years old. Optic atrophy and high frequency sensorineural hearing loss were found at 7 and 9 5/12 years of age, respectively. Her younger brother also developed Wolfram syndrome when he was 3 2/12 years old. Wolfram syndrome is also called DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy and deafness). This syndrome is transmitted as an autosomal recessive trait and is a progressive neurodegenerative disorder. It should be considered in a diabetic patient with unexplained optic atrophy, hearing loss, or polyuria and polydipsia in the presence of adequate blood glucose control. Visual acuity should be checked annually in patients with juvenile-onset diabetes mellitus. Optic atrophy should be considered if visual acuity is impaired.