Self-administered hyperventilation cardiopulmonary resuscitation for 100 s of cardiac arrest during Holter monitoring

An 80-year-old man remained conscious due to vigorous deep breathing during 100 s of ventricular arrest which was recorded on a Holter ECG. Arterial blood flow is considered to have been maintained by changes in intrathoracic pressure produced by deep respiratory movements. This case may represent a pure model of the "thoracic pump" mechanism.     

Distribution of light chains and ATPase activity of myosin in the atrioventricular conducting tissue of bovine heart

Summary The relations of the light chains of myosins of the atria, ventricles, and atrioventricular conducting tissue (specialized myocardial tissue) and the distribution of the light chains of myosin in different regions of the atrioventricular conducting tissue in bovine heart were examined. Two-dimensional gel electrophoresis showed that the atrial and ventricular myosins each had two light chains (LC₁ and LC₂). Ventricular LC₁ differed from atrial LC₁, but ventricular LC₂ corresponded to atrial LC₂. The specialized myocardial tissue myosin had three light chains (named here SL₁, SL₂, and SL₃). SL₁ comigrated with ventricular LC₁, SL₂ with atrial LC₁, and SL₃ with ventricular LC₂ and atrial LC₂. The compositions of the three light chains of myosins in various regions of the atrioventricular conducting tissue were determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The percentage proportion of SL₁ decreased in the order—atrioventricular node (AVN), right and left bundle branches (RLBB), His bundle (HIS), false tendon (FT) myosin; while the percentage proportion of SL₂ decreased in the order—FT and HIS, RLBB, AVN myosin. The percentages of SL₃ in these four regions were similar. The Ca²⁺-activated ATPase activity of myosin was highest in the AVN and lowest in the FT. The activities in the HIS and RLBB were intermediate between those in the AVN and FT. Thus, the composition of the light chains and the Ca²⁺-activated ATPase activity were different in various regions of the atrioventricular conducting tissue.     

Growth of asymptomatic unruptured aneurysms in follow-up study: report of three cases

The natural history of asymptomatic unruptured aneurysms that have not been subjected to surgery was studied radiologically using MRA and MRI and 3D-CT angiography (3D-CTA) commencing in 1993. We report on the growth of documented asymptomatic unruptured aneurysms in three patients. Growth of the aneurysms was followed by repeated MRA, MRI and 3D-CTA. In Case 1, a 71-year-old woman had been diagnosed as having a 3 mm unruptured anterior communicating artery aneurysm. The size of the aneurysm had expanded to 4 mm, 2 years later. This was detected during a follow-up MRA and confirmed by angiography. After this follow-up MRA, the aneurysm showed no change in size or shape for 8 years. Case 2 was that of a 75-year-old woman who had a 4.5 mm aneurysm involving the basilar artery and the superior cerebellar artery. 12 months later, an MRA was carried out as a follow-up study. This MRA revealed that the aneurysm had developed a bleb and was expanding. 8 months later the patient bled from the aneurysm and underwent surgery, but died. Before surgery, the diameter of the aneurysm, confirmed by angiogram, was 5.5 mm including the bleb. The third patient was a 66-year-old woman who had a 7 mm internal aneurysm involving the carotid artery and the posterior communicating artery. 3 years later a 3D-CTA detected the expansion of the aneurysm and development of an aneurysm bleb. 6 years later more expansion occurred and 3 months after that the patient bled from the aneurysm and underwent clipping. At that time, the diameter of the aneurysm, confirmed by angiography, was 13 mm including the bleb. In this follow-up study, patients with diagnosed asymptomatic unruptured aneurysms were followed up by MRA and MRI and 3D-CTA to determine risk factors for aneurysm rupture. We emphasize the fact that growth of an unruptured aneurysm and formation of blebs are important risk factors of aneurysm rupture.     

Suppression of IFN-gamma production in atopic group at the acute phase of RSV infection

Several studies have suggested that respiratory syncytial virus (RSV) bronchiolitis induced the change of cytokine production profile in childhood. We sought to determine whether the RSV-induced cytokine production was affected by the patient's atopic background. We quantified interferon-gamma (IFN-gamma) and interleukin (IL)-4 in the supernatant of peripheral blood mononuclear cells (PBMCs) cultured for 24 h and in the presence of phytohemaglutinin (PHA), IL-12, or IL-18, from 14 infants who were divided into two groups, those who are non-atopic and an atopic group. In RSV-infected infants with atopic diseases, IFN-gamma production from IL-12- or especially IL-18-stimulated PBMCs was subtotally suppressed in the acute phase, whereas in RSV-infected infants without atopic diseases IFN-gamma production was not suppressed on acute phase. The IFN-gamma suppression observed in the atopic group is not caused by the immaturity of an infant's immune system since reduced IFN-gamma production to RSV is not observed in the infants of non-atopic group. IFN-gamma suppression in regard to RSV infection might be caused by some genetic factor involved in the development of atopic disease such as IL-18 signal cascade.