Embolic myocardial infarction and left ventricular rupture due to mitral valve endocarditis.

A left ventricular rupture due to embolic myocardial infarction is extremely rare. A 72-year-old woman developed an acute embolic myocardial infarction and mitral regurgitation due to infective endocarditis. Two days after the infarction, a left ventricular free wall rupture occurred after transesophageal echo examination. She received an epicardial patch and mitral valve replacement. Perioperatively, an intra-aortic balloon pump and long-term antibiotics were used. The postoperative course was uneventful, and she is doing well 10 months after surgery.     

Oscillator mechanism of Notch pathway in the segmentation clock.

Somites are formed by periodic segmentation of the presomitic mesoderm (PSM). This periodic event is controlled by the segmentation clock, where Notch signaling plays an essential role. The basic helix-loop-helix factor Hes7, a Notch effector, is cyclically expressed by negative feedback and regulates cyclic expression of Lunatic fringe (Lfng), a Notch modulator. Lfng then seems to periodically inhibit Notch, leading to oscillation in Notch activity. It is thought that these coupled negative feedback loops by Hes7 and Lfng are important for sustained and synchronized oscillations in the PSM. Of interest, another Notch effector, Hes1, is cyclically expressed by many cell types such as neuroblasts, suggesting that this clock is widely distributed and regulates many biological events. This review summarizes the recent finding about roles and mechanism of Notch signaling in the segmentation clock and discusses the significance of Hes1 oscillation in non-PSM cells.     

Pericardial effusion following pulmonary resection

Objective Postoperative pericardial effusion commonly occurs after open heart surgery. However, after general thoracotomy such as pulmonary resection, there have been few reports of pericardial effusion. The purpose of this study is to investigate patients with pericardial effusion following pulmonary resection.Methods: Among 2,385 patients with pulmonary resection for lung neoplasm in our institute, eight patients, whose pericardium had never been opened during the operation, developed pericardial effusion. The clinical characteristics of the eight patients were analyzed.Results: Pericardial effusion after pulmonary resection was divided into two subtypes: pericardial effusion in three patients with left thoracotomy occurring within 30 days postoperatively, and pericardial effusion in the remaining five patients with right thoracotomy occurring more than 30 days postoperatively. Pericardiotomy or pericardiocentesis was performed in three symptomatic patients, and the remaining five asymptomatic patients were treated with diuretics. Pericardial effusion disappeared in three of the five patients about 1–3 months after the conservative treatment, while, in the remaining patients, because pericardial effusion had increased gradually, pericardiocentesis was performed.Conclusion: From our experience, the treatment strategy of drainage for early pericardial effusion and diuretics for late pericardial effusion seems to be appropriate. (Jpn J Thorac Cardiovasc Surg 2006; 54:193-198)     

CHARACTERISTICS OF HISTIOCYTIC LESIONS IN THE RETICULOENDOTHELIAL SYSTEM OF NZB MICE

The so-called Potter's lesion, previously described as preneoplastic in the lymph nodes of C58 mice, develops frequently in autoimmune NZB mice. These lesions were characterized in the present study by bands or sheets of palestaining histiocytic cells in the cortex and medulla of the lymph node, and multiple small nodules of the same cells were found in the red pulp of the spleen and the liver. Electron microscopically, the cells had pleomorphic cytoplasm with long processes, electron-dense bodies, abundant mitochondria, and a characteristic labyrinth structure with many C-type viruses. Mac-1 antigen, IgG-Fc receptor, ferritin, and ACPase activity were identified on these cells. Intraperitoneally-injected iron colloids were found in the lesions of the spleen and liver but not in those of the lymph nodes. The lymph node lesions appeared when the mice were about 3 months of age and enlarged until the mice were around 10 months old, after which they gradually receded and were replaced by small vessels and fibroblastic cells. These data indicate that the lesions represent reactive hyperplasia of the macrophage system and may have no direct association with the development of malignant lymphoma in NZB mice.     

Familial apoceruloplasmin deficiency associated with blepharospasm and retinal degeneration

A 52-year-old woman had a newly recognized disorder of familial hypoceruloplasminemia, blepharospasm, retinal degeneration, and high-density areas in CT of the basal ganglia and liver scan. Immunofixation electrophoresis disclosed apoceruloplasmin deficiency. Kinetic, x-ray analysis, and histochemical study showed accumulation of iron in liver and brain, but not of copper. Intestinal copper absorption was reduced, but liver uptake was increased. Ceruloplasmin is involved in iron metabolism, and the findings suggest that hypoceruloplasminemia due to lack of apoceruloplasmin was causally linked to the iron deposition in basal ganglia and other organs, leading to blepharospasm and retinal degeneration.     

Traumatic degeneration of transected myelinated fibers of the mouse sciatic nerve.

Traumatic degeneration of myelinated fibers was studied by electron microscopy over 5 days following transection of mouse sciatic nerve. Special attention was paid to the mechanism which separates the degenerating part, while preserving the viable part of the axon. Immediately after transection, the opened end of the proximal stump revealed extensive subcellular changes including the disorganization of neurofilaments, and disruption of mitochondria and axonal endoplasmic reticulum (SER). Subsequently, vesicles of round and tubular profiles filled up the whole area of the stump end, and proximal to it appeared a neurofilament-predominant area characterized by randomly oriented neurofilaments and normally appearing mitochondria and SER. Characteristic membranous demarcations occurred in early periods at the border between the vesicle accumulation and the neurofilament-predominant areas, and later also within these areas. The demarcation membranes formed both by invagination of the surface plasma membrane and, probably, by fusion of the large vesicles. These became prominent with time, dividing the axoplasm into compartments of varying sizes, which gradually underwent degeneration and were liberated from the parent axon. Occurrence of autophagic vacuoles was characteristic of the degenerating portions of the parent axon. Thus, by the function of demarcation membranes, the parent axon to be preserved could remain membrane-bound, while the degenerating parts were shed off.     

Veno-arterial ECLA (extracorporeal lung assist) for severe respiratory failure due to meconium aspiration

A full term newborn female, 3262g, aspirated meconium at birth and began to suffer from severe hypoxia and acidosis due to progressing pneumonitis, pneumothorax and pneumomediastinum. She also had severe hypotension and anuria. Venoarterial ECLA with a Kolobow membrane lung via the right internal jugular vein and the right common carotid artery was initiated. Blood gas parameters and blood pressure improved, and urine output increased to normal. ECLA permitted a reduction in FIO2 and airway pressure of mechanical ventilation, as well as frequent lavage of the lung. As the physical condition improved, the bypass flow was gradually decreased from 200 ml.kg-1.min-1 at the start to 130 ml.kg-1.min-1 for maintenance, then to 25 ml.kg-1.min-1 at the end. Bleeding throughout the ECLA for 69 hours could be minimized by a meticulous control of the activated coagulation time with a minimum dose of heparin and the transfusion of fresh frozen and platelet rich plasma. After ECLA, the carotid artery was simply ligated, and mechanical ventilatory support was carried out for 5 days. Her condition improved and she left the hospital without any neurological sequelae. ECLA will become an effective means of life support for a baby with severe MAS irresponsive to conventional ventilatory support.