Descending or Thoracoabdominal Aortic Aneurysm Repair Without Intercostal Vessel Reconstruction Using Contrast Magnetic Resonance Angiography: Report of Two Cases

Two high-risk patients underwent a graft replacement for descending thoracic or thoracoabdominal aortic aneurysms without the reconstruction of any intercostal and lumbar arteries. The first patient was an 81-year-old woman with asthma and renal dysfunction who was diagnosed to have a descending thoracic aortic aneurysm extending from the Th8 to Th12 level. Contrast magnetic resonance angiography (MRA) demonstrated the Adamkiewicz artery to originate from the left second lumbar artery. The second patient was a 59-year-old man with left ventricular dysfunction due to aortic and mitral stenoses who was diagnosed to have a Crawford type IV thoracoabdominal aortic aneurysm. Contrast MRA showed the Adamkiewicz artery to originate from the left ninth intercostal artery. In general, the reestablishment of the spinal cord's blood supply, whenever possible, is generally considered to be necessary in such patients to prevent spinal cord injury. However, the reimplantation of intercostal vessels is the most complex aspect of this surgical modality, and therefore, it may cause a substantial increase in the cardiopulmonary bypass time. However, at least in some cases, such as the two cases presented herein, the use of contrast MRA was found to reduce the risk in surgery for descending thoracic or thoracoabdominal aortic aneurysms by eliminating the need for any intraoperative management of the intercostal and lumbar arteries. Received: April 6, 2001 / Accepted: September 11, 2001     

Less-invasive thoracic aortic aneurysm repair

To minimize surgical trauma, we performed graft replacement of a descending aortic aneurysm through a minithoracotomy (12 cm) with the use of thoracoscopy and special vascular clamps. Contrast magnetic resonance angiography can be useful for preventing postoperative paraplegia by revealing the Adamkiewicz artery. The patient was satisfied with the postoperative comfort and good cosmetic result. Further refinement of the technique and instrumentation would make this technique a valuable adjunct to conventional thoracic aortic surgery.     

Preserved atrial response to dobutamine stress after the modified maze procedure for chronic atrial fibrillation: echocardiographic assessment of atrial function

BACKGROUND: The maze operation is effective in varying degrees for the restoration of atrial function at rest. However, the atrial mechanical function under stressed conditions has not been investigated. METHODS: Thirteen patients who regained normal sinus rhythm after the modified maze procedure for atrial fibrillation (Af) associated with valvular disease were enrolled in this study. A two-staged, low-dose protocol (at doses of 5 and 10 microg/kg/min) of dobutamine stress echocardiography (DSE) was performed to assess the probability of the appearance of atrial wave in 20 consecutive beats (Paw), the velocity of atrial filling wave (Av), and the early filling wave (Ev) with their ratio (A/E), as well as the left atrial area fraction (LAAF) which represents an ejection fraction of the left atrium. RESULTS: Under resting conditions, Paw was 72% and 50% at tricuspid (T) and mitral (M) position, respectively. During dobutamine stress (5 microg/kg/min), Paw tended to increase both at T and M position (86% and 60%, respectively). Av was significantly accelerated by dobutamine stress (10 microg/kg/min) in both T (from 0.36 to 0.54 m/s) and M (from 0.46 to 0.69 m/s) valvular flow, which was accompanied by a significant increase in A/E (from 0.69 and 0.31 to 0.87 and 0.40, respectively). Although heart rate was significantly increased during dobutamine stress, LAAF remained at the same level (0.18, 0.22 and 0.19 at rest, 5 and 10 microg/kg/min) and atrial output was expected to be enhanced by dobutamine stress. CONCLUSION: Restoration of atrial mechanical function after the maze operation is accompanied by preserved response to dobutamine stress.     

Aldosterone augments adrenomedullin production without stimulating pro-adrenomedullin N-terminal 20 peptide secretion in vascular smooth muscle cells

OBJECTIVE : Both adrenomedullin (AM) and pro-adrenomedullin N-terminal 20 peptide (PAMP), processed from the same precursor of prepro-adrenomedullin (preproAM), have differential biological properties; AM dilates blood vessels and presumably affects the vascular remodeling, while PAMP inhibits catecholamine secretion. Since aldosterone has been shown to be involved in vascular remodeling, we examined the effects of aldosterone on AM and PAMP secretion and preproAM gene expression in human aortic vascular smooth muscle cells (VSMC). METHODS : AM and PAMP secreted from human VSMC incubated with aldosterone were measured by radioimmunoassay, and preproAM gene expression was evaluated by quantitative polymerase chain reaction. RESULTS : Cultured human VSMC secreted both AM and PAMP into the media, while the secretion rate of AM was much higher than that of PAMP. Aldosterone increased preproAM gene expression in the cultured VSMC in a dose-dependent fashion following incubation for 48 h, with a concomitant increase in AM secretion from the cells, but PAMP secretion remained unchanged. Aldosterone-stimulated AM secretion was significantly reduced by spironolactone. Reverse-phase high-performance liquid chromatography analyses showed that immunoreactive AM secreted from the VSMC untreated or treated with aldosterone emerged at the point of human AM(1-52)-NH2. CONCLUSIONS : AM production was stimulated by aldosterone in cultured human VSMC without an increase in PAMP secretion, suggesting a possible role of AM in modulating vascular remodeling by aldosterone.     

Intravenous Gamma Globulin for Prolonged Passive Immune Thrombocytopenia

The effectiveness of intravenous gamma globulin was evaluated in prolonged thrombocyto penia in two infants of mothers with autoimmune thrombocytopenic purpura. Case 1, de spite unresponsiveness to steroid therapy, showed a slight response to intravenous gamma globulin infused at 15–19 days of age. A second administration of intravenous gamma globu lin at 70–74 days of age completely reversed the thrombocytopenia. In case 2, passive immune thrombocytopenia persisting over one month was reversed by the administration of intravenous gamma globulin at 37–39 days of age. A comparison of the effects of intra venous gamma globulin on the increase in platelet counts in the newborn infant (case 1) and in his mother showed that passive immune thrombocytopenia in neonates can be more resistant to therapy than autoimmune thrombocytopenic purpura in the mother. Adverse effects were not observed in either case. The effectiveness of and indications for intravenous gamma globulin in passive immune neonatal thrombocytopenia are discussed.     

Diffuse nodular lymphoid hyperplasia of the large bowel without hypogammaglobulinemia or malabsorption syndrome: a case report and literature review

Diffuse nodular lymphoid hyperplasia (DNLH) of the intestine is an extremely rare lymphoproliferative disorder occasionally associated with non-Hodgkin lymphomas. We report an unusual case of DNLH of the entire colon, which resembled malignant lymphoma (particularly low-grade B-cell lymphoma) both on clinical and pathologic grounds. The patient was a 62-year-old Japanese woman who was found to have multiple polypoid lesions along the entire large intestine by colonoscopy. Abdominal computed tomography revealed hepatosplenomegaly and multiple mesenteric lymphadenopathy. Histologically, the lesion was characterized by numerous lymphoid follicles with active germinal centers and a diffuse infiltrate of lymphoid cells in the mucosa and submucosa. The present case appears to be an essentially benign condition bearing a resemblance, both clinically and histologically, to malignant lymphoma, and from which it can be distinguished by use of immunohistochemical or molecular analysis.     

Malignant stromal tumor, so called "gastrointestinal stromal tumor", with rhabdomyomatous differentiation occurring in the gallbladder

Gastrointestinal stromal tumors (GISTs) constitute the largest category of primary nonepithelial neoplasms of the gastrointestinal tract. It is extremely rare that this tumor occurs in the bile tract, and only a few cases have been reported. Immunohistochemically, the tumor cells revealed a phenotype similar to Cajal cells, occasionally with differentiation to smooth muscle cells or neural cells. We present a case of malignant stromal tumor similar to GISTs with rhabdomyomatous differentiation of the gallbladder in a 68-year-old woman. The resected tumor was predominantly composed of spindle cells with rhabdomyomatous differentiation. Immunohistochemical study revealed diffuse staining of tumor cells using vimentin despite negative staining for desmin or S-100. This indicated a mesenchymal origin of the cells without smooth muscle or neuronal differentiation. Myoglobin-positive cells, in which phosphotungstic acid hematoxylin staining revealed cross striations of the cytoplasm, suggested rhabdomyomatous differentiation. Diffuse positivity for KIT in the cells suggested that the pathogenesis of this tumor may resemble that of GIST. The tumor may have derived from a mesenchymal stem cell that had undergone partial rhabdomyomatous differentiation.     

Non-incidental coamplification of Myc and ERBB2, and Myc and EGFR, in gastric adenocarcinomas.

This study was conducted to assess the frequencies of protein overexpression and gene amplification of Myc and to identify the mechanisms of Myc gene amplification, especially with regards to its possible coamplification with ERBB2 or EGFR in gastric adenocarcinomas. By immunohistochemical analysis of a total of 300 formalin-fixed and paraffin-embedded gastric adenocarcinomas, the nuclear overexpression of MYC was found in 47 tumors (16%). A fluorescence in situ hybridization (FISH) analysis revealed that nine (19%) of the 47 tumors with protein overexpression had cancer cells with high levels of Myc amplification, whereas only seven (6%) of the 122 tumors without protein overexpression showed high-level Myc gene amplification. Such Myc amplification was significantly correlated with positive nuclear protein overexpression. The coamplification of ERBB2 or EGFR with Myc that was found in six and four cases, respectively, is believed to be non-incidental because those frequencies were significantly higher than the individual frequencies observed for the total examined cases (ERBB2: 7%; EGFR: 4%). The high levels of gene amplification of these three genes, as visualized by FISH, could be broadly classified into two typical types, namely, 'multiple scattered signals' and 'large clustered signals'. Using two-color FISH, the coexistence of coamplified Myc and ERBB2, or Myc and EGFR, within single nuclei in various combinations of amplification types and copy numbers, could be ascertained in all nine cases, including one in which the synchronous 'multiple scattered type' coamplification of Myc and ERBB2 was observed. In three tumors, coamplification of ERBB2 and EGFR was found; however, ERBB2- and EGFR-amplified cell populations were separate and mutually exclusive. We propose that the non-incidental coamplification of Myc and either ERBB2 or EGFR occurred through translocation and subsequent rearrangement.