Alterations in cardiac troponin subunits in myocardial infarction

1. Alterations in troponin subunits in myocardial infarction were studied in the dog heart by the analysis of troponin-tropomyosin complex, i.e, native tropomyoin, of total structural proteins in SDS gel electrophoresis, and by the measurement of degree of activation of actomyosin-ATPase by Ca++. 2. At 12 to 24 hours after coronary ligation, reductions in TN-C and tropomyosin were observed followed by a decrease in TN-I at 48 hours. The relative contents of these subunits were the lowest at 72 hours to 7 days falling to less than 10% of those in the non-ischemic myocardium. On the contrary, TN-T was preserved through the course of myocardial infarction. 3. Actomyosin-ATPase activity was increased at 12 to 24 hours after coronary ligation and then reduced rapidly at 24 to 48 hours together with the degradation of myosin. However, the activation of actomyosin-ATPase by Ca++-troponin-tropomyosin was reduced already at 12 hours simultaneously with the reduction in TN-C, and almost completely lost at 48 hours. 4. Troponin subunits and actomyosin-ATPase activity returned to those of the control myocardium at 28 days after coronary ligation indicating the recovery of infarcted tissue.

Regional changes in cardiac structural proteins in myocardial infarction: biochemical and histologic correlates

1. Quantitative analysis of structural proteins from a minute amount of myocardial tissue was performed from 10 mu thick cardiac tissue slices weighing 2 to 5 mg by the extraction in glycerol solution and by sodium dodecylsulfate (SDS) gel electrophoresis, and these changes were compared with the histologic alterations in the striated structure of the adjacent cardiac slices in the experimental myocardial infarction in the dog. 2. Approximately 69 micrograms of structural proteins were obtained from 1 mg of the normal heart muscle. In the central portions of the myocardial infarction, reductions in myosin heavy chain (HC), light chain (LC) 1 and alpha-actinin were observed at 12 to 24 hours after the coronary occlusion followed by the decrease in myosin LC 2 at 48 hours. Those changes became intense at 72 hours to 7 days, but restored gradually at 14 to 28 days. 3. Alterations in the striated structure of cardiac muscle fibers of the adjacent tissues slices were found simultaneously with the changes in structural proteins. At 12 to 24 hours after the coronary ligation increase in eosinophilia and overstretch of cross-striation were observed. The findings of coagulation necrosis, loss of striation, fragmentation, swelling of A-band, etc. of the infarcted fibers were markedly observed at 48 hours to 7 days, but the histologic restoration of cardiac fibers was found with the recovery of the infarcted tissue at 14 to 28 days after the coronary ligation. 4. Changes in the compositions of structural proteins corresponded well to the alterations in the striated structure in chronology and in quantity.

Studies on the subcellular localization of electrolytes in normal and infarcted canine myocardium. With special reference to calcium ion

1. Alterations in subcellular distribution of electrolytes were studied with particular emphasis on Ca++ in normal and ischemic myocardium produced by ligating the coronary artery in the dog, by means of the histochemical method using potassium pyroantimonate. 2. In the normal myocardium, the antimonate precipitates were observed most abundantly in TC of SR and on N-line within sarcomeric I-band, but found scarcely in mitochondria, M-line, Z-line, intercalated disc or T-system. 3. In the infarcted myocardium, the precipitates were strikingly increased in both number and size in disrupted mitochondria, while they were markedly decreased in swollen TC with the progress of ischemia. 4. Most of the precipitates in TC and on N-line were removed by chelation with EGTA but a few larger precipitates were consistently found mainly on N-line. And the presence of Ca++ in the antimonate precipitates was confirmed by energy dispersive X-ray microanalysis.

Alpha-casein-binding proteins of guinea pig macrophage membranes and their possible roles in chemotaxis

The existence of specific binding proteins for alpha-casein, a well-known potent chemoattractant, on guinea pig peritoneal macrophages was demonstrated. Binding of 3H-alpha-casein to macrophages was found to be specific and reversible. Its association constant and the number of binding sites were 5.0 X 10(-6) M and 7.5 X 10(5) per cell, respectively. The presence of formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe), another chemoattractant, at a chemotactically active concentration (10(-11) to 10(-6) M) reduced this binding significantly. Pretreatment of macrophages with proteases such as trypsin and chymotrypsin decreased the number of binding sites for alpha-casein and the chemotactic response to alpha-casein. alpha-Casein binding proteins were isolated from radiolabeled macrophage surface membranes by affinity chromatography on a column of alpha-casein Sepharose 4B. SDS-polyacrylamide gel electrophoresis of the isolated proteins revealed three radioactive bands; two (MW 130,000 and 65,000) were glycoproteins, and the other (MW 100,000) was a protein which contained little carbohydrate. These three proteins were also isolated from the same source by affinity chromatography using a column of fMet-Leu-Phe-AH-Sepharose. This result, together with the observation that fMet-Leu-Phe inhibited the binding of alpha-casein to macrophages, indicated that alpha-casein and the tripeptide have at least partly common binding sites on guinea pig macrophages. Some of the proteins obtained in this work may constitute chemotactic receptors on the macrophage membrane.

[Pre-sacral epidermoid cyst communicating with spinal CSF cavity (author's transl)]

A 6-year-old girl was transfered to our hospital because of continuing pleocytosis, and detection of the squamous cells and cholesterin crystals in the CSF. Neurological examination on admission revealed no remarkable disorders, except for weakness of anal sphincter. X-ray examination of the spine showed a deformity of the sacral vertebra. Myelography revealed a pre-sacral cystic tumor, which was connected with spinal CSF cavity at cul-de-sac of the spinal canal by a narrow fistula. The tumor was totally removed and no meningitic sign appeared in postoperative course. Histological examination diagnosed it as a typical epidermoid tumor. Attention should be payed to the location, size, structure and clinical course in this particular case.

Studies of the cardiac sarcoplasmic reticulum in myocardial infarction

1. Influence of ischemia on the biochemical properties of the sarcoplasmic reticulum (SR) was studied in the experimental myocardial infarction in the dog. 2. Ca2+ -uptake rate of SR decreased at around 90 minutes after coronary occlusion. This reduction was roughly in parallel with the reduction in the Ca+ -Mg2+ -stimulated ATPase activity. However, Ca2+ -binding rate of SR was kept within the range of that of the non-infarcted tissue through the time course of myocardial infarction. 3. Ca2+ -Mg2+ -stimulated ATPase activity decreased at around 3 hours after coronary occlusion to about 50% of that of the non-infarcted portion. 4. In SDS gel electrophoresis, the protein band with the largest molecular weight among three major components decreased at 3 hours after coronary occlusion, which is suggestive of ATPase. At 48 hours after coronary occlusion, the protein with the smallest molecular weight in the major proteins also decreased. 5. Ca2+ -uptake rate, Ca2+ -Mg2+ -stimulated ATPase activity and the substructural changes return to the normal level and pattern at around 28 days after coronary occlusion.

Morphologic and biochemical studies on the experimental chronic ischemic myocardium with the Ameroid constrictor

1. Morphologic as well as biochemical alterations in chronic ischemic myocardial tissue without infarction were studied in dogs utilizing the Ameroid constrictor. 2. Serum creatine kinase activity elevated at around three weeks after placing the Ameroid constrictor around the circumflex branch of the left coronary artery suggestive of myocardial tissue injury followed by the initial activation caused by surgery. 3. Subendocardial proliferation of connective tissue was observed in about 60% of the experiments, but the middle and the subepicardial muscles were morphologically intact. 4. The marked increase in glycogen particles was observed in the subendocardial muscle cells in most of the experiments, and mild features of myocardial cellular necrosis were found in approximately 60% of the experiments. 5. ATPase activities of the structural proteins as well as sarcoplasmic reticulum in the ischemic myocardium shoed relatively higher values than those in the non-ischemic myocardium. However, no substructural changes were observed in SDS gel electrophoresis in both the fractions. 6. The alterations in the chronic myocardial ischemia are supposed to be essentially the same as those in myocardial necrosis followed by acute coronary occlusion.

Changes of cardiac structural proteins in myocardial infarction

1. Changes of structural proteins in experimental and human myocardial infarction were studied by the determination of myosin- and actomyosin-ATPase activities and gel electrophoretic analysis in the presence of sodium dodecyl sulfate (SDS). 2. In animal experiments using dogs, the relative amounts of myosin and alpha-actinin decreased at 24 to 48 hours after coronary ligation, became lowest at 72 hours, and remained at this level for 2 weeks and returned to almost normal value at 28 days. 3. Myosin- and actomyosin-ATPase activities decreased rapidly during 24 to 48 hours after ligation with temporary increase in their activities in the initial stage of ischemia and followed the similar time course as that of the amounts of myosin and alpha-actinin. 4. SDS gel electrophoretic analysis of structural proteins of infarcted tissues of the human hearts obtained from 5 cadavers showed also marked decrease of the contents of myosin and alpha-actinin with relative preservation of actin, tropomyosin and troponin-T.

Medical data base system with an ability of automated diagnosis

We carried out an experiment on a medical information system in which a clinical data base is combined organically with computer programs for automated diagnosis. In this system, the parameters for automated diagnosis are devised to be renewed as the contents of the data base (patient's information) increase. This system can be regarded as a data base possessing a kind of diagnosing ability which grows up with time. We have named this system "Intelligent Data Base". The algorithm for computer diagnosis used in this study is based on maximum likelihood method, and each likelihood is weighted with a prior probability of each disease. The discrimination efficiency of this method is logically equal to that of the Bayes rule. First 27 cases were learnt by the system and correct diagnosis was obtained in 78% of the cases. When cases for learning increased to 82, the percentage of correct diagnosis was improved to 95%.

Gel electrophoretic analysis of structural proteins of the normal canine and human hearts

1. Gel electrophoretic analysis of structural proteins extracted from myocardial tissues in the presence of sodium dodecylsulfate (SDS) is applicable to study the relative amount of structural proteins from less than 1 Gm of heart tissue. 2. The compositions of structural proteins of the right and left atria and ventricles of the normal canine heart were identical and similar to those of skeletal muscle. 3. The compositions of structural proteins of the atrium and ventricle of the normal human heart were also identical.

Electron microscopic studies on ATPase activities in myocardial infarction

Comparative studies of the fine structural changes and histochemical examination of adenosine triphosphatase (ATPase) activity were performed in canine ischemic heart muscle cells following left coronary artery ligation. In the intact myocardial cells, the ATPase activities were observed most intensely in the sarcoplasmic reticulum (SR), particularly in the terminal cisternae (TC), and moderately around gap junctions of the intercalated discs and on myofilaments. Ischemic cellular changes occurred three to 24 hours after coronary ligation and became severe after three to seven days. ATPase activities decreased at around 48 hours and also became weak at three to seven days. Two to three weeks after ligation, improvement of the fine structure and increase in ATPase activities were observed in the ischemic cells, suggesting recovery. ATPase activities in the ischemic cardiac cells appeared to be decreased in parallel with the process of the fine structural changes.

Activation of mouse splenic lymphocyte guanylate cyclase by calcium ion

The guanosine 3',5'-cyclic monophosphate (cGMP) level in the mouse splenic lymphocytes was increased about 2- to 3-fold by concanavalin A. This increase was completely dependent on the presence of Ca2+ in the medium. Homogenates of mouse splenic lymphocytes contained significant guanylate cyclase [EC 4.6.1.2] activity in both the 105,000 X g (60 min) particulate and supernatant fractions and both fractions required Mn2+ for full activity. Calcium ion (3mM) activated soluble guanylate cyclase 3-fold at a relatively low concentration of Mn2+ (less than 1mM) but inhibited the particulate enzyme slightly at all Mn2+ concentrations tested. Concanavalin A itself did not stimulate either fraction of guanylate cyclase. Thus these results suggest that elevation of the cGMP level in lymphocytes by concanavalin A might be brought about by stimulation of Ca2+ uptake and activation of soluble guanylate cyclase by the latter.