Dissecting aneurysm of the aorta and hypothyroidism.

A case of dissecting aneurysm of the aorta (DA) and atrophic thyroiditis causing clinically documented hypothyroidism is described. Subsequently, 101 cases of DA and 100 matched controls were reviewed. Notable thyroid pathology with potential hypothyroidism was seen in 22% of cases with DA. In the control group only 8% of the cases showed thyroid pathology. There appears to be overwhelming evidence for an association between dissecting aneurysm of the aorta and thyroid pathology. The link could be a disturbance of glycosaminoglycan metabolism, known to occur in both hypothyroidism and DA.

Physiological changes induced in cardiac myocytes by cytotoxic lymphocytes: an autoimmune model.

BACKGROUND: cytotoxic lymphocytes are important in the pathogenesis of several disease states, yet, the pathophysiology of lymphocyte-myocyte interaction is not well known. METHODS AND RESULTS: We have developed a model for the in vitro evaluation of autoimmune cytotoxic myocardial damage. Cardiac myocytes were repeatedly injected to adult autologous rats. Following 3 months, histological evidence of myocarditis was seen in 20% of the hearts. Cultured myocytes obtained from newborn rats were exposed to lymphocytes isolated from the immunized animals. Cytotoxic activity was measured using crystal violet staining test. The percentage of killing was increased as the ratio of lymphocytes/myocytes was increased. Verapamil did not block this cytotoxic effect. No killing was seen when myocytes were exposed to non-sensitized lymphocytes. Physiological changes induced in myocytes by cytotoxic lymphocytes were studied. Cell wall motion was measured by an optical method and action potentials with intracellular microelectrodes. Physiological changes observed in myocytes following exposure to cytotoxic lymphocytes included: Impaired relaxation with prolonged contractions, oscillations and prolongation of the plateau of the action potential. Cellular contraction was prolonged up to 4 s before total arrest of spontaneous activity. Verapamil but not tetrodotoxin restored action potentials and contractions to normal. Supernatant collected from cultures of myocytes and lymphocytes had the same effect on myocytes contractility as observed following exposure of myocytes to cytotoxic lymphocytes. CONCLUSIONS: This supports our hypothesis that these physiological alterations observed in myocytes are mediated by a soluble factor secreted by cytotoxic lymphocytes.

Cell damage by excess CuZnSOD and Down's syndrome.

Down's Syndrome (DS), the phenotypic expression of human trisomy 21, is presumed to result from overexpression of certain genes residing on chromosome 21 at the segment 21q22-the Down locus. The "housekeeping" enzyme CuZn-superoxide dismutase (CuZnSOD) is encoded by a gene from that region and its activity is elevated in DS patients. Moreover, the recent discovery that familial ALS is associated with mutations in the gene encoding CuZnSOD, focused attention on the entanglement of oxygen-free radicals in cell death and neuronal disorders. To investigate the involvement of CuZnSOD gene dosage in the etiology of the syndrome we have developed both cellular and animal models which enabled us to investigate the physiological consequences resulting from overexpression of the CuZnSOD gene. Rat PC12 cells expressing elevated levels of transfected human CuZnSOD gene were generated. These transformants (designated PC12-hSOD) closely resembled the parental cells in their morphology, growth rate, and response to nerve growth factor, but showed impaired neurotransmitter uptake. The lesion was localized to the chromaffin granule transport mechanism. These results show that elevation of CuZnSOD activity interferes with the transport of biogenic amines into chromaffin granules. Since neurotransmitter uptake plays an important role in many processes of the central nervous system, CuZnSOD gene-dosage may contribute to the neurobiological abnormalities of Down's Syndrome. As an approach to the development of an animal model for Down's Syndrome, several strains of transgenic mice which carry the human CuZnSOD gene have been prepared. These animals express the transgene as an active enzyme with increased activity from 1.6 to 6.0-fold in the brains of four transgenic strains and to an equal or lesser extent in several other tissues. To investigate the contribution of CuZnSOD gene dosage in the neuropathological symptoms of Down's Syndrome, we analyzed the tongue muscle of the transgenic-CuZnSOD mice. The tongue neuromuscular junctions (NMJ) in the transgenic animals exhibited significant pathological changes; withdrawal and destruction of some terminal axons and the development of multiple small terminals. The ratio of terminal axon area to postsynaptic membranes decreased, and secondary folds were often complex and hyperplastic. The morphological changes in the transgenic NMJ were similar to those previously seen in the transgenic NMJ and were similar to those previously seen in muscles of aging mice and rats as well as in tongue muscles of patients with Down's Syndrome. The findings suggest that CuZnSOD gene dosage is involved in the pathological abnormalities of tongue NMJ observed in Down's Syndrome patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Myocardial capillaries and autonomic nerves in diabetes: Morphometric study of auricles from bypass surgery biopsies.

Patients with diabetes mellitus are excessively vulnerable to myocardial ischemia and often suffer from autonomic cardiac dysfunction. They are also known to have specific capillary pathology and abnormalities of substances essential for the neoangiogenic cascade. These background data led us to the hypothesis that the severity of ischemic heart disease in diabetes is attributable (at least in part) to microcirculatory and autonomic inadequacy caused by microangiopathy and failure of postischemic adaptive neoangiogenesis. To test this hypothesis we compared myocardial capillaries, autonomic nerve endings of 19 diabetics, 30 normoglycemics with ischemic heart disease, and 9 valve replacements serving as nonischemic controls. Right atrial appendages obtained during coronary bypass surgery were utilized for light, fluorescent, and electron microscopic morphometry. Although in this series there were no significant differences in the clinical and laboratory hemodynamic values between the ischemic normoglycemic and diabetic patients, the latter showed marked capillary and nerve terminal pathology, and their capillary density as well as capillary to myofiber ratios were significantly lower. In addition, the mean capillary area, volume fraction, and intercapillary distance were higher in diabetics. The mean area of the nerve varicosities was also smaller, and this was correlated with capillary density. We concluded that the findings support the hypothesis that cardiac vulnerability in diabetes is connected with inadequate adaptive neoangiogenesis and that this seems to be associated with atrophic changes in the nerve terminals.

Effect of captopril on changes in rats' hearts induced by long-term irradiation.

The aim of this study was to test the efficacy of captopril, an angiotensin-converting enzyme inhibitor and a known suppressor of fibrosis, in preventing late radiation-induced cardiac pathology. Myocardial functional, histochemical and ultrastructural-morphometric studies were done on perfused hearts of rats isolated 3 and 6 months after 60Co gamma irradiation with 20 Gy and age-matched controls. At each time the animals were divided into the following groups: nonirradiated controls; irradiated once with 20 Gy; irradiated as above and given daily doses of captopril; daily doses of captopril without irradiation. The results showed that captopril, while ameliorating the decrease in the indices of capillary function, increase in mast cells, fibrosis, number of atrial granules, and changes in nerve terminals, failed to prevent the progressive functional deterioration of the hearts after irradiation. These findings suggest that an intramyofiber derangement may be involved in the long-term myocardial complications of irradiation.

Synovial copper deposition as a possible explanation of arthropathy in Wilson's disease.

A patient with longstanding Wilson's disease and arthritis is presented. Synovial biopsy disclosed thickening of the membrane, intimal histiocytes, and lymphocyte infiltration without pigmentation. X-ray energy spectroscopy demonstrated copper and iron in high concentrations. These findings may contribute to our understanding of the development of the arthropathy in patients with Wilson's disease.

Degenerative changes in the A375 melanoma line induced by transforming growth factor beta 1.

A375 human melanoma cell cultures grown in the presence of TGF beta contained greatly reduced cell numbers and exhibited drastic alterations in cell morphology compared to the control cultures. Preincubation of the cells with the cytokine for only 18 h was sufficient to induce these changes irreversibly. Examination of TGF beta-treated cells in the electron microscope revealed large numbers of lipid-filled vacuoles in the cytoplasm, greatly contracted nuclei and some loss of the otherwise abundant microvilli. Thus TGF beta may have a direct toxic effect on the A375 melanoma cells.

Myocardial dystrophin immunolocalization at sarcolemma and transverse tubules.

Using monoclonal antibodies against two different regions of the helical rod part of dystrophin, we have localized dystrophin on both plasma membrane and transverse tubules in cardiac muscle of man and several animal species. The staining persisted after experimental ischaemia, and was observed in long-standing heart disease. No immunostaining was seen at the intercalated discs. In skeletal muscle the same two antibodies stained only the plasma membrane.

Effect of ionizing radiation on neuromuscular junctions in mouse tongues.

Radiation damage to the neuromuscular junctions (NMJs) in mouse tongues was studied using local x-irradiation of the tongues with the rest of the body shielded. Transmission electron microscopy (TEM) revealed no significant morphological changes in the fine structures and organelles of the NMJs given 4 Gy. A dose of 8 Gy produced degenevative morphological changes associated with oxon terminal sprouting as early as 2 and 7 days following irradiation. Subsequently, 1-11 weeks later, severe degenerative changes were observed. The number of mitochondria was significantly decreased with increased occurrence of degenerative membranal features. The number of synaptic footplates without terminals or with multiple small terminals within one groove increased gradually with time. Most of these pathological changes persisted for at least 3 months after irradiation. However, the myofibres, blood vessels and interstitial cells appeared to be unaffected throughout the period of follow-up. The present study substantiates our previous reports of ageing-like changes in the tongues' NMJs induced by their excessive exposure to free radicals.

Human coronary microvessels in diabetes and ischaemia. Morphometric study of autopsy material.

The objective of this study was to test the hypothesis that excessive severity of ischaemic heart disease in diabetics is due, in part, to capillary inadequacy. Sections from autopsied hearts of diabetic patients with and without myocardial infarction as well as from those of patients with infarcts and no diabetes were used for morphometric studies of intramural microvessels in areas without infarction. Normoglycaemic patients with normal hearts were also examined. Two to five transverse sections from each of 44 hearts (stained with methenamine silver) were examined for capillary numerical density, capillary to myofibre ratios, and myofibre diameters. Averages for each case and totals for each group were calculated and compared. Normoglycaemic patients with infarcts had increased morphometric values. Diabetics with infarcts had significantly lower capillary densities than the other groups. In conclusion, it is suggested that in diabetes there is an inadequate ischaemia-induced, reactive angiogenesis. This may contribute towards increased myocardial vulnerability in further ischaemic injury and perhaps to diabetic cardiomyopathy.

Coronary capillaries in patients with congestive cardiomyopathy or angina pectoris with patent main coronary arteries. Ultrastructural morphometry of endomyocardial biopsy samples.

BACKGROUND: The coronary microvasculature may be abnormal even in the presence of angiographically normal epicardial arteries. Abnormalities of small coronary vessels have been invoked as a cause of angina. METHODS AND RESULTS: To quantitatively evaluate the morphology of capillaries in patients with idiopathic dilated cardiomyopathy (DCM) or the syndrome of angina and small vessel disease (SVD), we performed electron microscopic morphometry of capillaries in right ventricular biopsy samples taken from 32 patients. Ten had angina, normal epicardial coronary arteries, and evidence for SVD; 12 had DCM; and 10 had normal hearts. In patients with DCM, the ratio of microvessels to myocytes was not different than that of controls (0.49 +/- 0.06 versus 0.51 +/- 0.05). Mean cross-sectional areas of the capillaries (lumen plus wall) and lumen were significantly greater than those of controls (45.3 +/- 15.1 versus 22.7 +/- 8.3 micron 2, p less than 0.001; 17.6 +/- 6.9 versus 11.6 +/- 6.2 micron 2, p less than 0.05, respectively). Fibrous content of the myocardium, as assessed by quantitative light microscopy, was significantly increased (16.3 +/- 3.3% versus 5.0 +/- 2.4%, p less than 0.001). In contrast, in patients with SVD, the capillary-to-myocyte ratio was reduced (0.33 +/- 0.08, p less than 0.001). Although mean cross-sectional areas of the entire capillary (32.4 +/- 19.7 micron 2) and the lumen (8.9 +/- 7.8 micron 2) were not statistically different than those of controls, there was an absence of capillaries less than 15 micron 2 in cross-sectional area, and the frequency distribution of the lumen area was skewed to the left. Swollen endothelial cells frequently encroached upon the lumen. There was a mild increase in fibrous content (9.5 +/- 3.7%, p less than 0.05). CONCLUSIONS: Enlarged capillaries and a normal ratio of capillaries to myocytes appear to be features of DCM. Of the patients with SVD, there was both a relative lack of capillaries and capillary lumen narrowing from swollen endothelium. These changes may induce ischemia and angina and may result in mild fibrosis.

Myocardial pathology in rats exposed to prolonged environmental heat.

STUDY OBJECTIVE: The aim was to assess the role of continuously high environmental temperature in the genesis of tropical cardiomyopathies. DESIGN: Rats were kept in a climatic chamber at a constant temperature of 34 degrees C (40% relative humidity) for 1 or 2 months. Controls were kept at 24 degrees C. The hearts, either taken directly from the animals or following Langendorff perfusion, were then examined by light and electron microscopy. EXPERIMENTAL MATERIAL: 69 rats of two different strains, aged about 1 month, were used as the study group. There were 32 suitable controls. MEASUREMENTS AND MAIN RESULTS: The weights of the heated rats and their hearts were lower than controls but the body to heart weight ratio was unchanged. The maximum pressure developed by the left ventricle was higher. With light microscopy, focal necrosis, lymphoid and mast cell infiltrations, fibrosis, and occasional calcifications were seen in most heat exposed rats. With electron microscopy most myocytes appeared normal when taken from whole animals. The additional trauma of heart suspension or hypo-osmolar perfusion caused severe membrane related pathology, while controls remained unaffected. CONCLUSIONS: Prolonged exposure to heat produces focal cellular reactions and disturbance of the myocyte membrane. The pathogenesis of the changes is as yet uncertain. It may be multifactorial and include calcium and/or oxygen derangements mediated by mast cells, catecholamines, hypothyroidism, and heat shock proteins.

Capillary and myofiber ultrastructure in endomyocardial biopsies from cyclosporine-treated heart transplant patients.

This study focuses on the ultrastructure of microvessels and myofibers in 54 endomyocardial biopsy specimens from 16 patients treated with cyclosporine after heart transplantation. Although the capillary and myofiber pathologic condition was significantly correlated with the degree of rejection, ultrastructural changes sometimes occurred in biopsy specimens with little or no histologic cellular infiltration. Immunocytochemical studies of some biopsy specimens showed that all microvessels were positive for IgM, whereas concentrations of IgG, complement, and fibrin varied. The microvascular and myofiber changes appeared to be reversible and correlated (Pearson's coefficient of correlation of myofiber vacuoles and microangiopathy, R = 0.67, p less than 0.00001). The vacuoles in myofibers resembled those in subendocardial regions of ischemic myocardium. They could, however, be related to cyclosporine toxicity because similar vacuoles have been described in kidneys of transplant patients receiving cyclosporine. We conclude that in cases of unclear graft failure in the absence of classic signs of rejection, electron microscopy could be helpful in detecting microvascular and myofiber pathologic situations that may influence myocardial function.

Mildly dilated congestive cardiomyopathy. Use of prospective diagnostic criteria and description of the clinical course without heart transplantation.

Prognosis in classically described dilated congestive cardiomyopathy has been reported to be related to ventricular size. Mildly dilated congestive cardiomyopathy (MDCM) has been defined as end-stage heart failure of unknown etiology (New York Heart Association class IV, left ventricular ejection fraction less than 30%), occurring with neither typical hemodynamic signs of restrictive myopathy nor significant ventricular dilatation (less than 15% above normal range). The present study includes follow-up in 12 nontransplant patients. In the first 4 months after diagnosis, two patients improved and are living, and two showed cardiac dilation and clinical deterioration and died. Six of the remaining eight with persistent MDCM died (four with intractable heart failure and two, sudden deaths) without change in ventricular size before death, despite medical therapy over 20 +/- 8 months. Eight comparable transplanted patients with persistent MDCM demonstrated improved total survival by life table analysis (p less than 0.05). A family history of congestive cardiomyopathy was found in nine of 16 patients (56%) with persistent MDCM. Nontransplant patients were older (p less than 0.02), but other findings were similar in the two groups. Endomyocardial biopsies available in 14 of 16 cases showed little or no myofibrillar loss in spite of severe hemodynamic impairment. The degree of myofibrillar loss did not correlate with hemodynamic parameters but showed good correlation with left ventricular size, that is, five of six patients with no myofibrillar loss had normal ventricular size, whereas all eight patients with mild myofibrillar loss had mild cardiomegaly (p less than 0.002). Our current experience suggests a somewhat variable but negative prognosis after prospective diagnosis of MDCM, with poor survival in patients with persistence of the original diagnostic features during follow-up. Preservation of heart size in MDCM is probably related to lack of significant myofibrillar loss. Thus, irrespective of heart size or myofibrillar preservation on biopsy, heart transplantation should be strongly considered in MDCM if signs of severe cardiac dysfunction persist despite therapy.

Down syndrome clinical symptoms are manifested in transfected cells and transgenic mice overexpressing the human Cu/Zn-superoxide dismutase gene.

Down syndrome (DS), the phenotypic expression of human trisomy 21, is presumed to result from overexpression of certain genes residing on chromosome 21 at the segment 21q22-the Down locus. The "housekeeping" enzyme CuZn-superoxide dismutase (CuZnSOD) is encoded by a gene from that region and its activity is elevated in DS patients. To investigate the possible involvement of CuZnSOD gene dosage in the etiology of the syndrome we have developed both cellular and animal models which enabled us to investigate the physiological consequences resulting from overexpression of the CuZnSOD gene. 1. Rat PC12 cells expressing elevated levels of transfected human CuZnSOD gene were generated. These transformants (designated PC12-hSOD) closely resembled the parental cells in their morphology, growth rate, and response to nerve growth factor, but showed impaired neurotransmitter uptake. The lesion was localized to the chromaffin granule transport mechanism. We found that the pH gradient (delta pH) across the membrane, which is the main driving force for amine transport, was diminished in PC12-hSOD granules. These results show that elevation of CuZnSOD activity interferes with the transport of biogenic amines into chromaffin granules. Since neurotransmitter uptake plays an important role in many processes of the central nervous system, CuZnSOD gene-dosage may contribute to the neurobiological abnormalities of Down's syndrome. 2. As an approach to the development of an animal model for Down syndrome, several strains of transgenic mice that carry the human CuZnSOD gene have been prepared. These animals express the transgene in a manner similar to that of humans, with 0.9 and 0.7-kilobase transcripts in a 1:4 ratio, and synthesize the human enzyme in an active form capable of forming human-mouse enzyme heterodimers. CuZnSOD activity is increased from 1.6 to 6.0-fold in the brains of four transgenic strains and to an equal or lesser extent in several other tissues. 3. To investigate the possible involvement of CuZnSOD gene dosage in the neuropathological symptoms of Down's syndrome, we analyzed the tongue muscle of the transgenic mice that express elevated levels of human CuZnSOD. The tongue neuromuscular junctions (NMJ) in the transgenic animals exhibited significant pathological changes, namely, withdrawal and destruction of some terminal axons and the development of multiple small terminals. The ratio of terminal axon area to postsynaptic membrane decreased, and secondary folds were often complex and hyperplastic. The morphological changes in the transgenic NMJ were similar to those previously seen in muscles of aging mice and rats as well as in tongue muscle of patients with Down's syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of the toxicity of two trichothecenes applied topically to brain and liver of rats.

T-2 toxin has been found previously to be markedly more toxic upon intracerebral than upon systemic administration. In order to study the generality of this difference, we have applied to brain and liver of albino rats two different types of trichothecenes: T-2 toxin as a representative of 'simple' and myrotoxin B as a representative of 'macrocyclic' members of this series. Myrotoxin B, when applied intracerebrally, was about 100 times more poisonous than T-2 toxin. In contrast, upon intrahepatic injection both compounds exhibited similar degrees of toxicity. The different behavior of the two trichothecenes in the organs tested may be due to local metabolic factors.

[Follow-up of heart transplants].

6 patients, 37-55 years old, who underwent heart transplantation in Belgium, have been followed in our clinic for the past 2 years. All had suffered for 6-12 months from congestive heart failure which had not responded to intensive medical treatment and were considered terminal. 5 had had ischemic heart disease and 1 idiopathic dilated cardiomyopathy. After transplantation all patients were again in good physical condition and 5 of them had resumed a productive lifestyle. In 3, follow-up endomyocardial biopsies revealed episodes of "moderate rejection" of the transplant, all of which were successfully treated with pulse courses of corticosteroids and increased cyclosporine dosage. Mild renal failure developed in 3, and in 3 systemic hypertension, controlled by antihypertensive drugs. 4 patients examined in our department and found suitable for transplantation died before a compatible donor was found. In 2 other patients heart transplantation was not possible due to severe pulmonary hypertension. Heart transplantation is recommended for patients with terminal congestive heart failure unresponsive to medical treatment. Early transplantation prevents irreversible changes in the pulmonary vessels which would make operation impossible, and lowers operative risk.