John Wurzel

Effects of subcultivation and culture medium on differentiation of human fetal cardiac myocytes

SummaryPrevious work has suggested that subcultivated human fetal heart muscle cell cultures contain immature cardiac muscle cells capable only of limited differentiation after mitogen withdrawal. We studied several human fetal heart cultures (14–15 wk gestation) at several passage levels using immunocytochemistry, autoradiography, and Northern blot analysis. Characteristics in high-mitogen (growth) medium were compared with those after serum withdrawal. Cultured cells from one heart, expanded through 2 passages in growth medium, did not beat; however, 75% of cells did beat after subsequent culture for 24 days in low-serum (differentiation) medium containing insulin. In confluent cultures after 1 passage, there was no detectable difference in the number of cardiac myocytes present in growth medium compared with that 7 days after serum withdrawal. After 4 passages, however, serum withdrawal increased the number of cells expressing immunoreactive sarcomeric myosin heavy chain by 100-fold; expression of immunoreactive sarcomeric actin andα-cardiac actin mRNA also increased in the same cultures. Similar results were obtained in cultures kept in differentiation medium for 20 days before passage and expansion in growth medium. Using isopycinc centrifugation, a high-density cell fraction was isolated which contained no immunostained myocytes in growth medium but numerous myocytes after serum withdrawal. Combined immunocytochemistry/autoradiography showed that myocytes synthesize DNA in growth medium and in serum-free medium containing fibroblast growth factor, but not in serum-free medium alone. The results indicate that a) human fetal cardiac muscle cells proliferate in vitro and can maintain a phenotype characteristic of fetal myocytes after multiple subcultivations followed by serum withdrawal; b) after subcultivation in growth medium, some myocytes modulate their phenotype into one in which detectable levels of cardiac contractile proteins are expressed only after mitogen withdrawal, and c) the phenotype attained after serum withdrawal is in part dependent on passage level. Cultured human fetal myocardial cells my provide a useful experimental system for the study of human cardiac muscle cell biology.

Hematopoiesis/erythropoiesis in myocardial infarcts.

Extramedullary hematopoiesis occurring in the myocardium has previously only been reported in a single case of a neonate with cyanotic congenital heart disease. Herein we report the incidental discovery of extramedullary hematopoiesis or pure erythropoiesis in four failing adult hearts with myocardial infarction. In two cases, extramedullary hematopoiesis or erythropoiesis was identified in cardiectomy specimens removed at orthotopic heart transplantation; in two other cases, erythropoiesis was found in left ventricular tissue removed at the time of implantation of left ventricular assist devices. Myocardial hematopoiesis/erythropoiesis was identified based on characteristic light-microscopic findings in routinely processed tissue and was confirmed by immunhistochemistry using monoclonal antibodies to the erythroid cell marker glycophorin A (positive in all cases), the megakaryocyte marker CD61, and the granulocyte marker neutrophil elastase (the latter two markers positive in one case only). None of the four patients had a myeloproliferative disorder or evidence of a myelophthisic process. No hematopoietic elements were identified in 109 cardiectomy specimens without acute or recent infarcts. Myocardial hematopoiesis or erythropoiesis could represent heretofore-unrecognized manifestations of altered cytokine expression in patients with heart failure due to myocardial infarction.

Pulmonary Tumor Embolism

A 36-year-old woman with breast cancer was admitted with shortness of breath. A computed tomography angiogram was obtained and was negative for pulmonary embolism. She quickly developed hypoxemic respiratory failure and was transferred to the intensive care unit. She appeared to be improving when she suffered sudden cardiac death. Autopsy showed extensive lymphatic and vascular tumor emboli, which were the immediate cause of death. Tumor emboli are rarely diagnosed before death but seem to be more common than realized. It is important to recognize this entity, because there have been some case reports of cure. The usual mechanism of death is progressive right heart failure; sudden death from tumor embolism has rarely been described.

Myometrial cavernous hemangioma with pulmonary thromboembolism in a post-partum woman: a case report and review of the literature

IntroductionCavernous hemangiomas of the uterus are rare benign vascular lesions. Nine cases of diffuse cavernous hemangioma of the gravid uterus have been reported, most of which diffusely involved the myometrium. These vascular malformations are clinically significant, and may cause pronounced bleeding resulting in maternal or fetal demise. Thrombosis of cavernous hemangiomas of the uterus has been previously reported. We here report the first case in which a thrombosed cavernous hemangioma of the myometrium resulted in a fatal pulmonary embolism in a post-partum woman.Case presentationA 25-year-old obese African-American woman who had one pregnancy and was delivered of twins by cesarean section was admitted 1 week after the successful delivery. The 12-day clinical course included ventilator-dependent respiratory failure, systemic hypertension, methicillin-resistant Staphylococcus aureus in the sputum, leukocytosis and asystole. A transabdominal ultrasound examination showed heterogeneous thickened and irregular products in the endometrial canal. The laboratory values were relevant for an increased prothrombin time, activated partial thromboplastin time, ferritin and a decrease in hemoglobin. The clinical cause of death was cited as acute respiratory distress syndrome. At autopsy, a 400g spongy, hemorrhagic uterus with multiple cystic spaces measuring approximately 0.5 × 0.4cm filled with thrombi within the myometrium was identified. Immunohistological examination with a CD31 stain for vascular endothelium associated antigen confirmed several endothelium-lined vessels, some of which contained thrombi. These histological features were consistent with cavernous hemangioma of the myometrium. A histological examination of the lungs revealed multiple fresh thromboemboli in small- and medium-sized pulmonary arteries in the right upper and lower lobes without organization, but with adjacent areas of fresh hemorrhagic infarction.ConclusionThis case underscores the importance of a high index of suspicion in a pregnant or post-partum woman presenting with respiratory symptoms. Thrombosis of the cavernous hemangiomas of the gravid or post-partum uterus is a rare entity. This case is of interest because it indicates that this condition can be fatally complicated by embolization of the thrombi in the cavernous myometrial hemangiomas. Although delivery by conservative methods, as well as cesarean section, is possible without resorting to hysterectomy, occasionally, the consequences could be fatal as in this case.

Epicardial coronary artery intimal smooth muscle hyperplasia in a cocaine user

Accelerated epicardial coronary artery atherosclerosis has been well-documented in cocaine users. There are only two reported cases of cocaine-associated diffuse intimal expansion by proliferated smooth muscle cells causing significant coronary luminal compromise. This type of lesion histologically resembled chronic transplant arteriopathy. Here, we report a third such case.

HUMAN MYOCARDIAL CELL LINES GENERATED WITH SV40 TEMPERATURE-SENSITIVE MUTANT TSA58

SummaryConditionally transformed human myocardial cell lines would be a valuable resource for studying human cardiac cell biology. We generated clonal human fetal cardiocyte cell lines by transfection of fetal ventricular cardiac cell clones with a plasmid containing a replication-defective mutant of the temperature-sensitive SV40 strain tsA58. Multiple resulting cell lines showed similar features, namely: (1) T antigen (TAg) expression at both permissive (34°C) and restrictive (40.5°C) temperatures; (2) extended growth capacity in comparison with parental wild type, when grown at the permissive temperature; (3) both temperature-dependent and serum-responsive growth, and; (4) an incompletely differentiated fetal phenotype which was similar at both permissive and restrictive temperatures and in the presence and absence of serum. The transformed myocyte phenotype was demonstrated using immunocytochemistry, Western and Northern blotting, and reverse transcription-polymerase chain reaction (RT-PCR). Cell lines expressed skeletal α-actin, atrial natriuretic peptide (ANP), and keratins, but no sarcomeric myosin heavy chain or desmin. Immunoreactive sarcomeric actin was expressed predominantly as a truncated protein of approximately 38 kD. The phenotype of the transformed cells differs from that of the wild-type parental cells as well as from those reported by others who have used TAg to immortalize rodent or human ventricular myocytes. Our cell lines should provide a useful tool for study of the molecular mechanisms regulating growth and differentiation in human cardiac muscle cells.

CHAOS in the Mirror: Ballantyne (mirror) Syndrome Related to Congenital High Upper Airway Obstruction Syndrome

In the mirror syndrome, maternal edema mirrors fetal edema. The pathogenesis is unknown. The most common etiologic associations are rhesus isoimmunization, twin-twin transfusion syndrome, and viral infections. Less than 10% of reported cases are associated with congenital anomalies. We report a case due to congenital laryngeal stenosis, which also caused congenital high airway obstruction syndrome (CHAOS), characterized by pulmonary hyperplasia and edema or anasarca, related to airway abnormality. The fetal manifestations of the mirror syndrome and CHAOS overlap, but occurrence of the two in the same patient does not seem to have been reported.

Fatal gastrointestinal hemorrhage in a paraplegic man with undiagnosed AA (secondary) amyloidosis

We report a case of a 41-year-old African-American male paraplegic for more than 20 years, who had recurrent infections, renal failure with total urine protein of 840 mg/dL on urine protein electrophoresis and adrenal cortical insufficiency. He died suddenly of massive gastrointestinal (GI) hemorrhage. Autopsy showed clinically undiagnosed systemic amyloidosis involving the kidneys, adrenal cortices, spleen and small blood vessels of most organs and tissues, including those of the gastrointestinal tract. The history and autopsy findings indicated secondary or amyloid A (AA) amyloidosis. Paraplegia was one of the most common causes of secondary amyloidosis decades ago, but has now become unusual in patients with AA amyloidosis. Extensive involvement of GI small vessels was the most likely cause of fatal bleeding. GI amyloid previously has been shown to cause hemorrhage, but a fatal case has not yet been described.

Effects of growth factors on human cardiac myocytes

This review will summarize current knowledge regarding the effects of peptide growth factors on human cardiac myocytes in vitro and, when known, in vivo. Excellent reviews on this general topic which include studies of animal experimentation exist elsewhere [1,2], and thus this chapter will confine itself to human studies only.