Cardiac dimensions and motion shortly after mitral valve surgery

We studied 71 adult patients echocardiographically both before and 2-16 days (mean 8 days) after mitral valve surgery to systematically evaluate the early postoperative changes in cardiac dimensions and motion. The patients were divided into 4 groups: group I with predominant mitral stenosis (MS) (26 patients), group II with predominant mitral insufficiency (MI) (12 patients), group III with MS + MI (16 patients) and group IV with combined mitral and aortic valvular disease (17 patients). After operation the left atrial dimension at endsystole decreased (mean +/- standard deviation, 56 +/- 12 mm vs 46 +/- 11 mm, p less than 0.001), but did not completely normalize in the majority of patients. The left ventricular dimension at enddiastole decreased in group II from 67 +/- 12 mm to 54 +/- 5 mm (p less than 0.01) and in group IV from 59 +/- 13 mm to 54 +/- 13 mm (p less than 0.01), but increased in group I from 43 +/- 8 mm to 46 +/- 9 mm (p less than 0.05). Mitral EF slope increased from 15 +/- 11 mm/sec to 52 +/- 20 mm/sec (p less than 0.001) after commissurotomy, and decreased from 136 +/- 61 mm/sec to 66 +/- 30 mm/sec (p less than 0.05) after annuloplasty. However, the postoperative means were subnormal in these subgroups. Paradoxical or hypokinetic septal motion occurred in 5/71 (7%) before and 50/71 (70%) after operation. We conclude that: 1) partial normalization of cardiac dimensions and subnormal mitral EF slopes shortly after mitral valve surgery suggest a residual pressure gradient across the mitral valve as well as partial irreversibility of the heart after longstanding mechanical overloading, and 2) postoperative abnormal septal motion, which may be caused by pericardiotomy, can occur after any type of open heart surgery.

Fetus-in-fetu: report of a case

A case of fetus-in- fetu is reported. It occurred in an 8-week-old Korean boy who had been born by cesarean section due to abdominal distension. The fetus-in- fetu was connected to the superior mesenteric artery and consisted of two masses, apparently representing two portions of an acardiac monster. There was an amniotic membrane covering both masses, and the umbilical cord clearly was identifiable. One mass included the brain, eye, trachea, salivary glands, thyroid, pancreas, spleen, etc., while the other mass contained extremity bones, vertebrae, testis, adrenals, and intestinal loops. This is probably a case of separated fetus-in- fetu that showed unusually well-developed internal organs.

Impulse responses of automaticity in the Purkinje fiber

We examined the effects of brief current pulses on the pacemaker oscillations of the Purkinje fiber using the model of McAllister , Noble, and Tsien (1975. J. Physiol. [Lond.]. 251:1-57). This model was used to construct phase-response curves for brief electric stimuli to find "black holes," where rhythmic activity of the Purkinje fiber ceases. In our computer simulation, a brief current stimulus of the right magnitude and timing annihilated oscillations in membrane potential. The model also revealed a sequence of alternating periodic and chaotic regimes as the strength of a steady bias current is varied. We compared the results of our computer simulations with experimental work on Purkinje fibers and pointed out the importance of modeling results of this kind for understanding cardiac arrhythmias.

Recording of auditory evoked potentials in man using chronic subdural electrodes

With the aid of chronic subdural electrodes we have been able to record from the posterior banks of the sylvian fissure, auditory evoked potentials (AEPs) that had morphologies and peak latencies compatible with the primary AEPs described by Celesia and Puletti (1969). These AEPs had amplitudes that were not only affected by the side of stimulus presentation but were maximal in an area close to the primary auditory cortex. The AEPs also displayed an extremely steep spatial gradient and were not altered by pentobarbitone sodium and nitrous oxide anaesthesia. Together, these properties suggest that these subdurally recorded potentials are near-field evoked potentials from the primary auditory cortex. The focal nature of these potentials also allows them to be used as effective electrophysiological tools for localization of the primary auditory cortex in patients.

Biochemical analysis and electron microscopy of human mitral valve collagen in patients with various etiologies of mitral valve diseases

Biochemical analyses and electron microscopy of mitral valve collagen were carried out in 29 patients with various mitral valve diseases. They were divided into 3 groups: (1) rheumatic heart disease (15 patients), (2) isolated rupture of chordae tendineae (8 patients), and (3) floppy mitral valve (6 patients). Normal mitral valves obtained at necropsy from 6 patients who died from extracardiac causes were used for control observations. Results of the electrophoretic analysis of the collagen of normal and diseased valves showed that all valves contained collagen types I, III, and AB collagen with similar electrophoretic patterns. Electron microscopic observations and comparisons of the segment-long-spacing crystallites of each type of collagen revealed similar band patterns, irrespective of the normal or diseased valves sources. It is concluded that the composition and primary molecular structure of mitral valve collagen are usually not altered in a wide variety of disease processes affecting the mitral valve.

On the mechanism of spiking and bursting in excitable cells

A mathematical model previously developed to explain beta-cell membrane potential oscillations has been modified to accommodate the external variation of K+, Na+ and Ca2+ concentrations. Our model, which is applicable to excitable cells, incorporates the barrier kinetics. Hodgkin-Huxley-type gating mechanism, and an electrogenic Na+-K+ pump. Numerical solutions of our model are in agreement with many of the experimental results reported in the literature on excitable cells.

Scanning and transmission electron microscopic studies on isolated ruptures of chordae tendineae

Electron microscopic studies of chordae tendineae of the mitral valve were carried out in 17 patients who underwent mitral valve replacement due to a spontaneously isolated rupture of chordae tendineae. The normal chordae, used as the control group, were obtained at autopsy from 5 patients who died from extracardiac causes and were compared with the ruptured chordae. In all patients with chordal rupture, scanning electron microscopy showed perforations of the chordae tendineae, with extensive desquamation and disruption of the endothelial cells and wide-spread destruction of the collagen fiber bundles in the central collagenous core. These pathological findings were not observed in the normal chordae from the control group. Transmission electron microscopy showed that the ruptured chordae were characterized by heterogeneous collagen fibrils with intrinsic structural alterations and disorganization in fibril arrangement. There was a wide variation in the diameters of collagen fibrils which always showed abnormal morphology, with abnormally large, peculiarly shaped fibrils. Apparent loss and/or a disordered arrangement of the typical periodicity of the fibrils were frequently observed. In addition, various degrees of degenerative changes of collagen tissue were often present. These abnormalities were never seen in the fibrils of the normal chordae, and were observed consistently in both the fibrils of the ruptured chordae and in the macroscopically intact chordae in the group with spontaneous rupture of chordae tendineae. These results suggest that a defective organization of collagen into fibrils and fibers, associated with secondary degeneration of collagen within the central collagenous core of the chordae tendineae, are important pathogenetic mechanisms for spontaneously isolated ruptures of chordae tendineae.

Chediak-Higashi syndrome in a Chinese infant

Chediak-Higashi syndrome in Chinese has not been previously reported in the English literature. A 14-month Chinese girl who presented with partial oculocutaneous albinism and Pseudomonas infection was found to have the classical intracytoplasmic inclusion bodies in the leucocytes by light and electron microscopy. Other characteristic features typical of this syndrome included hepatosplenomegaly, defective chemotaxis, and coarse but sparse melanin granules in hair shaft. She was also found to have hypertriglyceridaemia, a rare lipid abnormality occasionally reported in children suffering from this syndrome. Despite vigorous therapy with high dose ascorbate, corticosteroid and intravenous antibiotics, she died in the accelerated phase of Pseudomonas septicaemia.

Failure of uptake of radiocolloid by the femoral heads: a diagnostic problem: concise communication

One hundred six patients had the area of the femoral head scintigraphed after completion of a Tc-99m sulfur colloid liver scan. In 47 (45%), there was no visible activity in the femoral heads. This was somewhat age-related. All six individuals in the 11- to 19-yr age group showed femoral-head uptake of radiocolloid, but only 37% of those 70 to 79 yr old revealed such accumulation. The finding that less than one half of adults had uptake of radiocolloid in the femoral heads was consistent with results of three smaller series of patients (larger dose of radiocolloid, use of a different preparation of sulfur colloid, and use of In-III chloride). We conclude that not all adults take up radiocolloid in the femoral heads, and that lack of such uptake is not necessarily abnormal. Use of radiocolloid accumulation to gauge femoral-head vascularity may be more limited than previously appreciated, although right-left asymmetry might be of some diagnostic assistance.

Intestinal absorption of calcium in rats given diets containing casein or amino acid mixture: the role of casein phosphopeptides

1. In an attempt to investigate calcium absorption in the rat during the postprandial period, with the least alteration of the physical environment, the undisturbed small intestine was ligated in situ 2.5 or 3.0 h after ingestion of a diet containing 200 g casein/kg or an equivalent amino acid mixture, or 925 g casein/kg. Estimation of Ca absorption was made by comparing the amount of soluble 40Ca or 45Ca in the contents of segments from the rats receiving 45Ca by intubation 30 min after withdrawal of food, ligated after a further 30 min, then killed after 0 or 30 min. 2. Under conditions such that the estimated amount of a marker, polyethylene glycol, in segments ligated in a defined position was little changed in rats killed 30 min apart, the difference in the amount of soluble 40Ca was much higher in the rats fed on the basal diet containing 200 g casein/kg than in other groups. 3. This specific effect on Ca absorption, particularly in the distal portion of the small intestine, could be seen also after 45Ca was directly injected into ligated segments in situ. The amount of 45Ca in the portal blood 15 min after injection of the label was also highest in the rats given the basal diet. 4. The results were in agreement with our previous findings that the formation and accumulation of casein phosphopeptides causes an increase in the amount of soluble Ca in the distal small intestine.

The relationship of transmembrane potential to surface morphology of human atrial muscle and cardiac hemodynamics

A correlative study of transmembrane potential characteristics, surface morphological features of human atrial muscle, and cardiac hemodynamics was carried out in 41 patients, who were divided into 2 groups based on the level of the mean maximum diastolic potentials (MDP). Group A consisted of 19 patients with MDP values ranging from -60.0 to -82.0 mV (mean +/- S.D. = -65.70 +/- 6.63 mV). Group B included 22 patients who had abnormally low MDP (range -36.0- -58.5 mV, mean +/- S.D. = -48.14 +/- 6.72 mV). The differences in electrophysiological data were statistically significant. However, there were no significant differences in the hemodynamic data between the 2 groups. Furthermore, there was poor correlation between the electrophysiological and hemodynamic data in both groups. In group A, scanning and transmission electron microscopy revealed either no changes or only mild alterations in the surface morphology of the atrial myocardium. Various degrees of surface morphological changes, including a focal loss of the endothelium which was always associated with endocardial fibrosis, irregular thickening and lamination of the glycocalyx, disruption of the sarcolemma and complete destruction of the surface membrane structures were more often observed in group B. These results provide valuable evidence that sarcolemmal changes may underlie the electrophysiological alterations in diseased human atria. We suggest that the principal pathogenetic mechanisms leading to the transmembrane potential changes are the altered surface morphology of atrial myocardial cells, resulting from underlying disease processes.

Scanning electron microscopy of human lungs in various forms of heart disease

The surface morphologic features of the lung obtained from 21 patients with various forms of heart disease were investigated by scanning electron microscopy, with particular emphasis on the correlation between the surface pathology and cardiopulmonary hemodynamics. There were almost no pathologic findings on the bronchiolar and alveolar surfaces in patients with normal pulmonary arterial wedge pressure (PAWP). The characteristic changes of the surface morphology of the lung parenchyma in patients with abnormal elevation of PAWP included various degrees of desquamating loss of the bronchiolar epithelium associated with inflammatory cell infiltration and fibrotic changes and focal epithelial disruption of the individual alveoli which often extended to involve the surface of the entire alveoli with perforated rupture of the alveolar septa. The severity of abnormal surface morphologic findings of the lung seemed to correlate to the degree of PAWP. From our results it is concluded that chronic lung congestion plays a major role in the pathogenesis of the surface pathologic changes of the lung in patients with heart disease of various etiologies. Our findings may provide a clearer understanding of the structural and functional relationship of congestive lung and a clinical explanation for pulmonary manifestations in patients with chronic congestive heart failure.

Partial restriction map of Marek's disease virus DNA

A partial restriction map of Marek's disease virus (MDV) DNA was constructed by digestion with endonucleases BamHI, Bg/I and SmaI and by blotting hybridization. The data suggest that there is a terminal heterogeneous sequence at least on one end of the MDV DNA molecule. The data did not reveal four different orientations of the terminal fragments of MDV DNA molecules despite the observation that MDV DNA contains inverted repeat sequences as also present in Herpes simplex virus (HSV) DNA molecules (Cebrian et al., 1981). Terminal deletion of MDV DNA, SalI-H and I, was found in high passage number preparations.

Effects of oral disopyramide phosphate on induction and sustenance of atrioventricular reentrant tachycardia incorporating retrograde accessory pathway conduction

We performed electrophysiologic studies before and after oral administration of disopyramide phosphate, 200 mg every 6 hours, in 20 patients with atrioventricular (AV) reentrant tachycardia using a retrogradely conducting accessory pathway. Disopyramide markedly depressed retrograde accessory pathway conduction by increasing the mean ventricular paced cycle length that produced ventriculoatrial block (less than or equal to 287 +/- 4 to greater than or equal to 392 +/- 22 msec, p less than 0.01); it also depressed antegrade normal pathway AV conduction by increasing the atrial paced cycle length that produced AV block (287 +/- 9 to 328 +/- 7 msec, p less than 0.01). In 14 patients, tachycardia could not be induced or sustained after disopyramide phosphate. In 13 patients, this reflected depression of the retrograde limb with either absence of atrial echoes (nine patients) or induction of nonsustained tachycardia that terminated after the QRS complex (four patients), and in one, it reflected depression of the antegrade limb with induction of a single atrial echo not followed by a QRS response. In six patients, sustained tachycardia could still be induced after disopyramide. Oral disopyramide phosphate is effective in preventing induction of sustained AV reentrant tachycardia in most patients. This effect is achieved by depression of the retrograde limb of the reentrant circuit.

The surface morphology and ultrastructure of renal arterial smooth muscle cells in patients with renovascular hypertension

The surface and internal ultrastructure of renal arterial smooth muscle cells were investigated in 3 patients with renovascular hypertension. The most characteristic features of the surface pathology in hypertrophied smooth muscle cells consisted of various degrees of surface defects, including both extensive loss of surface details and an irregular thickening and disruption of the basement membrane, which was widely separated from the plasma membrane by a clear space. Ultrastructural changes include the appearance of highly lobulated nuclei, multinucleation, disorganization of myofilaments and increased numbers of rough-surfaced sarcoplasmic reticulum and mitochondria, which are usual manifestations of cellular hypertrophy. These results suggest that ionic movement across the cell membranes, particularly of Ca2+, is probably abnormal in hypertrophied smooth muscle cells. This may result in functional disorders of hypertensive arteries.