Orthostatic hypotension in elderly persons during passive standing: a comparison with young persons

BACKGROUND: The present study was aimed at clarifying the mechanism of orthostatic hypotension (OH) that occurs in elderly persons and at investigating assisting methods to prevent OH by evaluating changes in autonomic nervous system (ANS) activity and cerebral circulation of elderly persons when engaged in passive standing. METHODS: Eight elderly volunteers and 9 young volunteers gave informed consent to participate in the study. Two experimental conditions were established: (i) "active standing," in which the subjects stood on their own with guidance from an assistant, and (ii) "passive standing," in which the subjects were placed in a standing position completely by an assistant. ANS was determined before and after standing by measuring the heart rate variability. The reaction of the ANS was evaluated on the basis of low-frequency power (LF: 0.05--0.15 Hz) and high-frequency power (HF: 0.15--0.4 Hz), which were separated from the R-R interval data by power spectral analysis using the fast Fourier transformation. Cerebral perfusion was measured over the right frontal region using a near-infrared spectroscopy cerebral oxygen monitor. RESULTS: The main findings were: (i) Transient decreases in blood pressure occurred immediately after standing in both the young and elderly subjects. (ii) The LF:HF ratio increased significantly ( p <.05) immediately after active standing in the young subjects, whereas this ratio increased in the elderly subjects after some delay. (iii) The LF:HF ratio increased significantly ( p <.01) immediately after passive standing in the young subjects, whereas this ratio decreased significantly ( p <.05) in the elderly subjects. (iv) In the elderly subjects, the total hemoglobin (HbT) and oxyhemoglobin showed the greatest decrease during the 15-second period after standing. The maximum changes in the HbT with passive standing differed significantly ( p <.01) from those observed during active standing. CONCLUSIONS: Our findings emphasize the need to devise bioengineered means that allow elderly persons to exert themselves, to maintain or improve muscle contractility and ANS function, while providing minimum assistance for standing.     

Blood pressure distribution and determinants of higher levels of blood pressure in Japanese rural adolescents

The blood pressures (BP) and anthropometric values of 1,014 Japanese rural school children aged 12-17 years old were measured at one-year interval. The strongest correlation for systolic BP (SBP) was weight and for diastolic BP (DBP) it was age. Larger values of weight, body mass index, triceps skinfold thickness and smaller increment of height showed significant discriminative powers in differentiating the subjects who had been above the age-sex specific 80th percentile value (H-H group) from those who had been below the 20th percentile value (L-L group) for both SBP and DBP. Subjects with a family history of hypertension (FHH) had higher SBP than those without a FHH, and were more prevalent in H-H group for SBP. These results indicate that larger body size and more mature stature are determinants of higher levels of BP during adolescence, and that FHH affects SBP only in this period.     

Rapidly growing mural thrombus in an abdominal aortic aneurysm

Summary While mural thrombus accompanied by an abdominal aortic aneurysm (AAA) is not rare, the growth rate of such a thrombus has not yet been adequately documented. We present here a very rare case of a 62-year-old female patient with an AAA in whom the mural thrombus in the aneurysm grew very rapidly over a short period. We could follow the growth of the mural thrombus in the AAA by two-dimensional (2-D) abdominal echography. Patients with an AAA must be closely monitored by this technique which is able to detect the presence of the thrombus and allow evaluation of its growth.     

A case of AIDS-complicated lung infection mimicking acute eosinophilic pneumonia]

A 34-year-old man was admitted with dyspnea and low grade fever. Chest radiograph and computed tomography (CT) showed bilateral, ground glass opacities and perihilar consolidation. Bronchoalveolar lavage (BAL) was performed. The percentage of eosinophils in the BAL fluid (BALF) was elevated (20.5%). BALF smear and culture showed normal flora. Acute eosinophilic pneumonia was diagnosed and steroid therapy was performed. Afterwards he was transferred to our hospital. The HIV antibody was positive and peripheral blood CD-4 positive lymphocytes decreased to 10/microl, cytomegalovirus (CMV) antigenemia was positive and beta-D-glucan increased. CMV infection and pneumocystis pneumonia (PCP) complicated with AIDS was diagnosed. Trimethoprim/sulfamethoxazole, ganciclovir, and antifungal drugs were administered, but he suffered pneumothorax on the 18th day after admission and died. Histopathologic findings from an autopsy lung specimen revealed CMV infection and PCP. It is known that the percentage of eosinophils in the BALF increases in some cases of PCP complicated with AIDS. We emphasize that it is necessary to consider PCP when the percentage of eosinophils in the BALF increase.     

Determination of the site of the accessory pathway in WPW syndrome by an electrocardiographic inverse solution

The initial portion of the QRS complex in WPW syndrome might be represented by a single dipole, since the delta wave corresponds to the localized ventricular activation propagated over the accessory atrioventricular pathway. In order to examine whether the site of the accessory pathway in WPW syndrome could be localized by an equivalent dipole method, the dipole positions during the delta wave were determined in 30 patients using a three dimensional model of the torso and were then compared with the sites of accessory pathways localized by body surface maps. The single dipole approximation during the delta wave appeared to be appropriate since the index of the nondipolarity of the potentials was as low as 28% on average. The dipole positions determined on the atrioventricular ring during the delta wave were compatible with the sites of accessory pathways localized by body surface maps in 22 of the 30 patients. The dipole positions were adjacent to the sites of accessory pathways in 7 of the remaining 8 patients. Thus the equivalent dipole method might be an additional noninvasive tool to determine the site of the accessory pathway in WPW syndrome.     

Rate-dependent changes in atrial action potential duration after short- duration rapid atrial pacing in humans.

The effect of rapid atrial pacing on the rate adaptation of the atrial action potential duration was studied in humans. The right atrial monophasic action potential (RAMAP) of 5 patients was recorded before and after 30 min of rapid atrial pacing. The pacing cycle length (CL) was 146 +/- 9 ms, the shortest duration at which 1:1 capture was possible. The RAMAP duration at 90% repolarization (RMAPD) was measured. CL-dependent changes in RAMAPD (CL 600 ms-CL 300 ms) before and after rapid atrial pacing were 51.8 +/- 10.7 ms and 30.8 +/- 7.6 ms (p < 0.05), respectively.     

Autonomic responses to orthostatic stress in head-up tilt testing: Relationship to test-induced prolonged asystole

Background: Prolonged asystole is sometimes an extreme manifestation of neurally mediated syncope. Hypothesis: To investigate the mechanism of head-up tilt testing-induced prolonged (life-threatening) cardiac asystole, we measured temporal changes in frequency domain heart rate variability indices in 25 patients with syncope of undetermined etiology. Methods: Head-up tilt testing (80°) was performed in 25 patients for up to 40 min or until asystole or syncope occurred. Three patients (Group 1; 37 ±13 years, 1 man, 2 women) had an episode of prolonged cardiac asystole (≥ 10 s) during testing, necessitating cardiopulmonary resuscitation. Syncope, but no asystole, was induced in 10 patients (Group 2; 48 ± 31 years, 6 men, 4 women), and 12 patients (Group 3; 55 ± 20 years, 5 men, 7 women) failed to show asystole or syncope during testing. Power spectra of low (0.04–0.15 Hz) and high (0.15–0.40 Hz) frequency, and total (0.01–1.00 Hz) frequency spectra were measured in consecutive 2 min segments throughout the test. Results: Maximally changed values in heart rate, systolic blood pressure, and heart rate variability indices during testing were compared among the three groups (maximally changed values did not include the values during tilt-induced symptoms). High frequency spectra in Groups 2 and 3, but not in Group 1, decreased during the test. High frequency spectra, low frequency spectra, and total spectra in Group 1 were significantly higher than those in Groups 2 and 3 during testing. In Group 1 patients, findings at test-induced asystole were consistent with exaggerated sympathetic and concurrent persistent parasympathetic activity. Conclusion: Unusual autonomic responses to orthostatic stress can cause prolonged asystole, and this autonomic nerve dysregulation may relate to asystolic episodes associated with cardiovascular collapse.     

Quantitative Monitoring of Circulating Epstein-Barr Virus DNA for Predicting the Development of Posttransplantation Lymphoproliferative Disease

Epstein-Barr virus (EBV)-DNA was quantitatively measured to assess posttransplantation virus reactivation by real-time polymerase chain reaction (PCR). In the first retrospective analysis of a 7-year-old boy with lymphoproliferative disease (LPD) after an unrelated cord blood transplantation, serum EBV-DNA progressively increased to 4 x 10(5) copies/mL. EBV load was then prospectively monitored in peripheral blood from posttransplantation patients. The second case was an 8 year-old boy with aplastic anemia who received a CD34+ cell transplantation. This patient died of LPD with the progression of pulmonary nodules. EBV-DNA increased to 4 x 10(4) copies/mL after the control of cytomegalovirus reactivation. On the other hand, EBV-DNA was undetectable (<200 copies/mL) in the series of all 58 samples from 10 patients who did not develop LPD after hematopoietic stem cell transplantation. Sequential monitoring of circulating EBV-DNA by quantitative PCR may be a useful indicator for predicting the development of posttransplantation LPD.     

Conformational investigation of peptides using solid‐state NMR spectroscopy—A study of polymorphism of β‐turn peptides containing diprolines

The construction of complex protein folds relies on the precise conversion of a linear polypeptide chain into a compact 3‐dimensional structure. In this context, study of isolated secondary structural modules containing short stretches of amino acids assumes significance. Additionally, peptides, both natural and synthetic, play a major role as potential drugs. With a view to understand the local conformations adopted by peptides in the solid state, we propose a multinuclear NMR approach utilizing spectra of nuclei in their natural isotopic abundance. Various solid‐state NMR experiments have been utilized for assignment of the spectra. Additionally, the gauge‐including projector augmented‐wave (GIPAW) calculations were used to confirm the assignments. Particularly, the utility of the double‐quantum–single‐quantum correlation experiments is highlighted for the purpose of assignment and for inferring the conformation across the peptide bond. The methodology is illustrated for the case of designed peptides containing diproline residues occurring at the β‐turns for identifying their cis‐trans conformational polymorphism. The proposed method promises to be of use in the study of conformations of small‐ to medium‐sized peptides such as antimicrobial peptides and in the study of polymorphism leading to applications in drug development protocols.     

Early non-convulsive seizures are associated with the development of acute encephalopathy with biphasic seizures and late reduced diffusion

IntroductionChildren with either febrile seizure or acute encephalopathy exhibit seizures and/or impaired consciousness accompanied by fever of unknown etiology (SICF). Among children with SICF, we previously reported those who have refractory status epilepticus or prolonged neurological abnormalities with normal AST levels are at a high risk for the development of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), considered to be caused by excitotoxicity. Non-convulsive seizures (NCS) are common in critically ill children and cause excitotoxic neuronal injury. The aim of this study was to elucidate the prevalence of NCS in the acute phase of children at a high risk for developing AESD and the relationship between NCS in the acute phase and neurological outcomes.MethodsWe studied 137 children with SICF at a high risk for developing AESD and who underwent continuous electroencephalogram monitoring (cEEG) upon admission to a tertiary pediatric care center at Hyogo Prefectural Kobe Children’s Hospital between October 2007 and August 2018. Patient characteristics and outcomes were compared between patients with NCS and without NCS.ResultsOf the 137 children, NCS occurred in 30 children; the first NCS were detected in cEEG at the beginning in 63.3%, during the first hour in 90%, and within 12 h in 96.7%. Neurological sequelae were more common in NCS patients (20.0%) than in non-NCS patients (1.9%; p = 0.001). Five in 30 NCS patients (16.7%) and 3 in 107 non-NCS patients (2.8%) developed AESD (p = 0.013).ConclusionThe occurrence of NCS is associated with subsequent neurological sequelae, especially the development of AESD.