Cross sectional echocardiographic demonstration of the mechanisms of abnormal interventricular septal motion in congenital total absence of the left pericardium

OBJECTIVE

To investigate the influence of the absence of the pericardium on the left ventricular wall, particularly on interventricular septal motion, using M mode and cross sectional short axis echocardiography in patients with congenital total absence of the left pericardium.

METHODS

21 patients with, congenital total absence of the left pericardium were divided into three groups according to the interventricular septal motion; systolic type (n = 6) with paradoxical motion during systole, diastolic type (n = 11) with abnormal posterior motion during mid to late diastole, and mixed type (n = 4) with paradoxical motion during systole and abnormal posterior motion during diastole.

RESULTS

On cross sectional short axis echocardiograms of the left ventricle, in the diastolic type the degree of angular displacement of the papillary muscles during end diastole to end systole showed excessive anticlockwise rotation about the long axis of the left ventricle without marked anteroposterior displacement. In the systolic type, there was shift of the left ventricle towards the anteromedial portion in systole and towards the posterolateral portion in diastole without significant rotation. There was a significantly positive correlation between the degree of angular displacement and the amplitude of diastolic interventricular septal motion during mid to late diastole in all patients.

CONCLUSIONS

There was abnormal interventricular septal motion during systole and diastole in patients with total absence of the left pericardium. Abnormal systolic motion was induced by anteroposterior displacement of the left ventricle, and abnormal diastolic motion by left ventricular rotation about the long axis of the heart during the cardiac cycle. Analysis using cross sectional echocardiography was useful for elucidating the mechanisms of abnormal interventricular septal motion.

The 'sail sound' and tricuspid regurgitation in Ebstein's anomaly: the value of echocardiography in evaluating their mechanisms

We describe a patient with Ebstein's anomaly in whom Doppler echocardiography was used to clarify the mechanism responsible for 'sail sound' and tricuspid regurgitation associated with this condition. Phonocardiography revealed an additional early systolic heart sound, consisting of a first low-amplitude component (T1) and a second high-amplitude component (T2, 'sail sound'). In simultaneous recordings of the tricuspid valve motion using M mode echocardiography and phonocardiography, the closing of the tricuspid valve occurred with T1 which originated at the tip of the tricuspid leaflets, while T2 originated from the body of the tricuspid leaflets. Using color Doppler imaging, the tricuspid regurgitant signal was detected during pansystole, indicating a blue signal during the phase corresponding to T1 and a mosaic signal during the phase corresponding to T2 at end-systole. Thus, 'sail sound' in patients with Ebstein's anomaly is not simply a closing sound of the tricuspid valve, but a complex closing sound which includes a sudden stopping sound after the anterior and/or other tricuspid leaflets balloon out at systole.

Appropriate osteotomy site and number in limb lengthening

The effects of the placement of osteotomy site on osteogenesis during monofocal and bifocal lengthening were investigated in 47 immature rabbits allocated to 4 groups according to osteotomy site: (1) monofocal in the proximal diaphysis; (2) monofocal in the distal diaphysis; (3) bifocal in the proximal and distal diaphysis; and (4) bifocal in the proximal diaphysis. The right tibia was distracted at an overall rate of 1.0 mm per day for 15 days. These groups were compared by assessment of soft radiograph findings and torsional strength 2 and 6 weeks after the end of distraction. Microangiography was done in 5 rabbits in the bifocal proximal and distal group. The proximal distracted site showed favorable bone regeneration compared with the distal site, and torsional strength was significantly greater in the proximal than in the distal osteotomy group. Less bone formation and lower torsional strength were observed in the bifocal proximal diaphysis group, with short intermediate segment, than that in the other bifocal group, with long intermediate segment. The nutrient artery in the latter group was preserved in the intermediate segment and reanastomosed to the metaphyseal arteries. These results suggest that the proximal diaphysis is more suitable for the osteotomy site than is the distal diaphysis. In a 2-level osteotomy, the inflow site of the nutrient artery should be included within the intermediate segment.

Regulation of interleukin (IL)-1beta gene transcription induced by IL-1beta in rheumatoid synovial fibroblast-like cells, E11, transformed with simian virus 40 large T antigen

OBJECTIVE

To investigate the process involved in the production of and responsiveness to interleukin 1beta (IL-1beta) in synovial fibroblast-like cells, we analyzed the enhancer region of pro-IL-1beta gene in a cell clone, E11, established from a patient with rheumatoid arthritis (RA).

METHODS

A cell clone, E11, was derived from rheumatoid synovial fibroblast-like cells transformed with simian virus 40 large T antigen expression vector by electroporation. Responsiveness of E11 to IL-1beta was analyzed by [3H] thymidine incorporation and Northern blotting. IL-1beta responsive elements on pro-IL-1beta gene were analyzed by chloramphenicol acetyltransferase analysis.

RESULTS

E11 resembled synovial fibroblasts based on morphological characteristics and phenotypic analysis. It also demonstrated marked enhancement of proliferation and rapid induction of IL-1beta mRNA expression by IL-1beta. We also identified IL-1beta responsive elements on the pro-IL-1beta gene at a position between -3134 and -3092 that contains the AP-1 binding site and between -2782 and -2729, which includes both AP-1 and nuclear factor-kappaB (NF-kappaB) binding sites.

CONCLUSION

AP-1 and NF-kappaB binding elements were required for transcriptional regulation of the IL-1beta gene in the autocrine growth system of RA synovial cells.

Rheumatoid synovial fibroblasts are stimulated by the cellular adhesion to T cells through lymphocyte function associated antigen-1/intercellular adhesion molecule-1

OBJECTIVE

To determine if T cells stimulate synovial fibroblasts to produce inflammatory cytokines through cellular adhesion in synovitis of rheumatoid arthritis (RA).

METHODS

Immunohistochemical staining, flow microfluorometry, adhesion assay, ELISA, and Northern blot analysis to determine production of interleukin-1beta (IL-1beta) from RA synovium and RA synovial fibroblast-like cell line.

RESULTS

We observed the following novel features of cellular adhesion of T cells to synovial fibroblasts, which suggest a role for induction of cytokine production in synovial fibroblasts: (a) CD11a (lymphocyte function associated antigen-1 alpha) positive T cells accumulated around CD54 [intercellular adhesion molecule (ICAM-1)] positive synoviocytes in active RA synovium, shown by immunohistochemical studies: (b) synovial fibroblastic cell line E11 expressed a single adhesion molecule ICAM-1, the expression of which was not affected by IL-1beta; (c) E11 adhered to phorbol myristate acetate (PMA) activated T cells within 30 min, not resting T cells, and its adhesion was completely inhibited by anti-LFA-1 monoclonal antibody (Mab); (d) pretreatment of E11 with IL-1beta did not affect the adhesion of E11 to PMA activated T cells; (e) IL-1beta production and IL-1beta mRNA transcription from E11 were induced by the addition of T cells in a cell number dependent manner and the induced production and transcription were inhibited by anti-LFA-1 Mab.

CONCLUSION

T cells infiltrating the synovium may play a pivotal role in the pathogenesis of RA, by inducing IL-1beta production of synovial fibroblasts by sequential events, namely, T cell-synoviocyte cellular adhesion through LFA-1/ICAM-1, signal transduction, and production of IL-1beta induced by the cellular adhesion.

Immunolocalization of type I or type II activin receptors in the rat brain

We have studied immunolocalization of activin receptors in the central nervous system using polyclonal antibodies (IgG) to type I (50-55 kDa, ActRI), type II (70-75 kDa, ActRII) or a subtype of type II known as type IIB (ActRIIB) receptors of activin. A total of 7 antisera to rat activin receptors was generated, i.e. 3 kinds of antisera to the extracellular domain (ActRI(81-89), ActRII(91-100), or ActRIIB(90-99)) and 4 antisera to the kinase domain (ActRI(323-333), ActRII(307-319), ActRII(407-420) or ActRIIB(306-319)). The region of aa 407-420 of ActRII is identical with that of ActRIIB. At first, we characterized these antibodies by Western blot analysis using ovarian proteins fractionated by preparative SDS-PAGE. All antibodies to ActRII and ActRIIB specifically reacted with 75 kDa-proteins which could also bind to activin-A. Anti-ActRII(91-100) antibody also reacted with 62 kDa-proteins which were capable of binding with activin-A. Although no positive reactions to anti-ActRI(81-89) antibody were seen in ovarian proteins, a positive reaction was detected at 52 kDa only when the proteins were deglycosylated. By use of these antibodies, immunolocalization of activin receptors was examined in the rat brain. The patterns of expression of activin type I and type II receptors were different. Positive reactions to anti-ActRII(91-100) antibody were detected in neurons of the cerebral cortex, hippocampus, medial amygdala and thalamus. In the hypothalamus, some neurons of the supraoptic nucleus were weakly stained, and widely scattered neurons of the lateral hypothalamic area were moderately stained. On the contrary, the most intense reactions to anti-ActRI(81-89) antibody were detected in neurons of the lateral hypothalamic area. In addition, many neurons of the cerebral cortex were also stained, but neurons of the hippocampus and the amygdala were not stained. These results suggest that activin may have physiological roles not only for hypothalamic neuroendocrinological and feeding-related systems as suggested previously but may also have functions in cortical and limbic pathways as a neuromodulator or for maintenance of neurons.

Comparison of accelerated hyperfractionated radiotherapy and conventional radiotherapy for supratentorial malignant glioma

Between 1988 and 1993, 71 patients with glioblastoma or anaplastic astrocytoma were treated either with accelerated hyperfractionation radiotherapy (1.5 Gy twice daily to a total dose of 69 Gy, n = 35) or with conventional fractionation radiotherapy (1.8 Gy daily to 64.8 Gy, n = 36). Two patients in each group did not complete radiotherapy, leaving 67 evaluable. All patients received the chemotherapeutic regime ACNU intraarterially (50 mg/m2) or intravenously (100 mg/m2) prior to and after radiotherapy. Between 1990 and 1992, 19 patients also received intravenous interferon-beta (3 x 10(6) U, three times weekly) during radiotherapy. The median survival time was 14.5 months for the accelerated hyperfractionation group and 14 months for the conventional fractionation group. The median time to progression was 12 months for the accelerated hyperfractionation group and 9.5 months for the conventional fractionation group. There was no significant difference in either survival (P = 0.89) or progression-free survival (P = 0.25) between the accelerated hyperfractionation and conventional fractionation groups. Interferon therapy was associated with poorer survival. Brain necrosis developed in four out of 10 patients receiving accelerated hyperfractionation radiotherapy plus interferon-beta, but in none of nine patients receiving conventional fractionation radiotherapy plus interferon (P = 0.033). In conclusion, our study failed to demonstrate any possible benefit of accelerated hyperfractionation radiotherapy for malignant glioma. The incidence of brain necrosis may be increased by combining accelerated hyperfractionation radiotherapy and interferon-beta.

Expression of prolactin gene in mouse placenta during late pregnancy: detection of mRNA and its translation product

To examine the existence of PRL messenger ribonucleic acid (mRNA) in the mouse placenta during late pregnancy, reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blot analysis were carried out followed by nucleotide sequence analysis of cDNA. Total RNA extracted from each tissue was reverse-transcribed, followed by PCR with two oligonucleotide primers specific or a part of mouse PRL (mPRL) cDNA. An amplified RT-PCR product of predicted size was detected in all samples from the placenta of days 16 and 18 pregnant mice. This product was specifically hybridized with a probe overlapping an entire sequence of mPRL cDNA in Southern blot analysis. Nucleotide sequence analysis also provided evidence that the amplified cDNA had a nucleotide sequence completely identical to the mPRL cDNA sequence reported previously. Furthermore, mPRL with a slightly bigger molecular weight than that of pituitary PRL was detected in the placenta of days 12, 14, 16 and 18 pregnancy by immunoblot analysis. These results suggest that PRL mRNA and its translation product are synthesized in mouse placenta during late pregnancy.

Unfused C2C12 mouse skeletal muscle cells express neurofilament 140K protein

Expression of neurofilament 140K protein in C2C12 mouse skeletal muscle cells was studied. Immunofluorescence and immunoblot analyses revealed that NF140K was expressed at the proliferative stage and was colocalized with the muscle-specific intermediate protein desmin. As muscle cell differentiation proceeded, the number of NF140K-positive cells decreased whereas the number of cells expressing muscle-specific marker proteins such as sarcomeric myosin heavy chain and troponin-T increased. Down-regulation of NF140K and upregulation of a myogenic regulatory gene, the myogenin gene, started simultaneously. In differentiated muscle cell cultures, unfused cells residing between myotubes remained NF140K-positive. NF140K and desmin double-positive cells were also found in a primary culture of adult mouse skeletal muscle cells. The results suggest that NF140K may be a unique marker for uncommitted myoblasts.

Mapping of a gene for the increased susceptibility of B1 cells to Mott cell formation in murine autoimmune disease

Mott cells, a pathologic state of plasma cells containing intracellular inclusions of Igs (Russell bodies), are frequent in lymphoid tissues of murine and human autoimmune diseases. However, neither the genesis nor the significance of Mott cells in autoimmune diseases is well understood. We found that B1, but not B2, cells were induced in vitro to form Mott cells in the presence of LPS or IL-5, but not other stimulants, in a much higher frequency in autoimmune New Zealand Black (NZB) and NZB x New Zealand White (NZB/W) F1 than in non-autoimmune disease-prone mice and notably athymic nude NZB/W F1 mice. Cell surface phenotypes of Mott cells were B220+ CD5+ CD43+ CD11b(dull), while those of peritoneal macrophages were B220- CD5- CD43(dull) CD11b+. We mapped a locus (provisionally designated Mott-1) controlling Mott cell formation that was tightly linked to microsatellite marker loci, D4 Mit70 and D4 Mit48, of autoimmune NZB mice, which is in close proximity to our recently mapped locus Imh-1 for hypergammaglobulinemia. This region contains candidate genes that may be relevant to the aberrant B cell activation and differentiation. We suggest that while the Mott cell by itself is not the effector for autoimmune disease, the genetically determined aberrant maturational process of B1 cells that underlies the pathogenesis of autoimmune disease forms the basis for Mott cell formation in a T cell-dependent manner.

Mapping of a gene for the increased susceptibility of B1 cells to Mott cell formation in murine autoimmune disease

Mott cells, a pathologic state of plasma cells containing intracellular inclusions of Igs (Russell bodies), are frequent in lymphoid tissues of murine and human autoimmune diseases. However, neither the genesis nor the significance of Mott cells in autoimmune diseases is well understood. We found that B1, but not B2, cells were induced in vitro to form Mott cells in the presence of LPS or IL-5, but not other stimulants, in a much higher frequency in autoimmune New Zealand Black (NZB) and NZB x New Zealand White (NZB/W) F1 than in non-autoimmune disease-prone mice and notably athymic nude NZB/W F1 mice. Cell surface phenotypes of Mott cells were B220+ CD5+ CD43+ CD11b(dull), while those of peritoneal macrophages were B220- CD5- CD43(dull) CD11b+. We mapped a locus (provisionally designated Mott-1) controlling Mott cell formation that was tightly linked to microsatellite marker loci, D4 Mit70 and D4 Mit48, of autoimmune NZB mice, which is in close proximity to our recently mapped locus Imh-1 for hypergammaglobulinemia. This region contains candidate genes that may be relevant to the aberrant B cell activation and differentiation. We suggest that while the Mott cell by itself is not the effector for autoimmune disease, the genetically determined aberrant maturational process of B1 cells that underlies the pathogenesis of autoimmune disease forms the basis for Mott cell formation in a T cell-dependent manner.

Ets-1 regulates angiogenesis by inducing the expression of urokinase-type plasminogen activator and matrix metalloproteinase-1 and the migration of vascular endothelial cells

The coordinate induction of protease activities and cell migration is a principal feature of endothelial cells (ECs) invading the interstitial space in the initial step of angiogenesis. However, the molecular mechanisms of these events are not fully characterized. Ets-1 is a member of the ets gene family of transcription factors, which binds to the Ets binding motif in the cis-acting elements and regulates the expression of certain genes. Four typical angiogenic growth factors, aFGF, bFGF, VEGF, and EGF, induced the expression of ets-1 mRNA in either human umbilical vein endothelial cells (HUVECs), ECV-304 cells (immortalized HUVECs), or human omental microvascular endothelial cells (HOMECs). The expression of ets-1 reached its maximum at 2 hr after factor addition and then decreased to the basal level by 12 hr. For characterization of the role of Ets-1 in angiogenesis, ets-1 antisense and sense oligodeoxynucleotides (ODNs) were constructed. The ets-1 antisense ODN but not sense ODN efficiently blocked the synthesis of Ets-1 protein by human ECs in response to angiogenic growth factors. Moreover, the ets-1 antisense ODN but not sense ODN almost completely abolished the binding of endothelial cell extract to DNA containing the Ets binding motif. The expression of urokinase-type plasminogen activator and matrix metalloproteinase-1 and the migration of ECs in response to growth factors were significantly inhibited by ets-1 antisense ODN but not by sense ODN. Tube formation by HOMECs in type 1 collagen gel stimulated with EGF was abrogated by ets-1 antisense ODN. Finally, the expression of Ets-1 protein in ECs during angiogenesis in vivo was confirmed by an immunohistochemical analysis using a murine angiogenesis model. These results indicate that the induction of ets-1 mRNA is a mutual phenomenon in ECs stimulated with angiogenic growth factors. Ets-1 appears to play an important role in angiogenesis, regulating the expression of proteases and the migration of ECs.

Cloning and characterization of novel gene, DCRR1, expressed from Down's syndrome critical region of human chromosome 21q22.2

The new gene, DCRR1, from the proximal part of the Down's syndrome critical region (DCR) was identified by the GRAIL analysis of the 97-kb nucleotide sequence of two P1 DNAs and the cDNA for DCRR1 gene was cloned. A 7.36-kb cDNA encodes the imcompleted open reading frame composed of 1941 amino acid residues (220.2 kDa). The deduced amino acid sequence contains the conserved domain for protein phosphatases at the N-terminus. The domain encoding the rod-like tail of a myosin heavy chain was also found near the C-terminal region besides the signature for an actin binding protein, profilin, suggesting its possible role as a microtuble-associated protein. Two different sizes (7.9 and 9.0 kb) of mRNAs were detected in the poly(A)+ RNA from abundant tissues by the Northern analysis. The smaller transcript was only transcribed at a high level in the testis. The imbalance of the DCRR1 gene dosage may contibute to the pathogenesis of Down's syndrome.

Subsets of activated T cells in patients with systemic lupus erythematosus: the relation to cell cycle

The correlation among the various markers of activated T cells (soluble interleukin 2 receptor (sIL-2R), HLA-DR+ and HLA-DP+ T cells, proliferating cell nuclear antigen (PCNA) positive lymphocytes) were examined in patients with systemic lupus erythematosus (SLE), and related to the cell cycle. The concentration of sIL-2R and the proportion of HLA-DR+ T cells, HLA-DP+ T cells or PCNA+ lymphocytes were increased significantly as compared to that in normal subjects. And, the concentrations of sIL-2R correlated with the proportions of PCNA+ lymphocytes, but not with the proportions of HLA-DR+ T cells, HLA-DP+ T cells. The correlation between sIL-2R and PCNA+ lymphocytes was attributed to both indicators being increased during the G1B or S phase in normal T cells upon stimulation by phytohemagglutinin (PHA). Upon cell cycle analysis it was learned that activated T cells could be found in the G1A and the S phases.

Determination and drug modification assessed by micronucleus frequency assay of potentially lethal damage repair in quiescent cell populations within murine solid tumors

We investigated potentially lethal damage repair (PLDR) by quiescent (Q) tumor cells in vivo. SCC VII tumor-bearing C3H/He mice were irradiated with 60Co gamma-rays after being given 10 injections of 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in their tumors, and the tumors were than excised and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (Cyt-B, a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling was determined using immunofluorescence staining for BrdU. Thus, the MN frequency was determined for cells not labeled by BrdU; for all practical purposes, such cells can be regarded as the Q cells in a tumor. The MN frequency in the total (P + Q) tumor cell population was determined from irradiated tumors that were not pretreated with BrdU. Assays were performed immediately after irradiation alone, 24 hours after the injection of cis-diaminedichloroplatinum(II) (CDDP), mitomycin C (MMC), misonidazole [1-(2-nitro-1-imidazolyl)-3-methoxy-2-propanol] (MISO), 3-aminobenzamide (3-AB), camptothecin (CPT) or caffeine (CAF) following irradiation, and 24 hours after irradiation alone. Q cells were more radioresistant and had a greater capacity for PLDR than the tumor cell population as a whole. CDDP and MISO (especially the latter) inhibited PLDR more strongly in Q cells than in the tumor cell population as a whole. However, CPT and CAF exerted similar inhibition of PLDR in Q cells and in the tumor cell population as a whole. This assay method appears to be useful for detecting the responses of Q tumor cells to various chemical agents.

Increased cartilage and bone formation in spontaneously hypercholesterolemic rats

Spontaneously hypercholesterolemic (SHC) rats are known to exhibit accelerated bone resorption. We compared endochondral bone formation induced by implantation of demineralized bone matrix (DBM) to 4-week-old SHC rats with that of age-matched Sprague-Dawley (SD) rats. When DBM prepared from adult SD rats was implanted, the cartilageous area enlarged, and C-propeptide of type II procollagen content on day 7 was higher in SHC rats. Alkaline phosphatase activity and calcium content on day 12 and tartrate-resistant acid phosphatase activity on day 19 were higher in SHC rats. These results suggest active chondrogenesis, with a subsequent increase in osteogenesis, and stimulated osteoclastic bone resorption in SHC rats. When DBM from 10-week-old SHC rats was implanted into SD or SHC rats, the levels of bone forming parameters on day 12 were reduced to one-third, suggesting inhibiting factor(s) for bone induction in bone matrix of SHC rats. In contrast, when DBM from 6-month-old SHC rats was implanted, although bone forming parameters in SD rats were comparable to the case of implantation of DBM from SD rats, the accelerated bone formation detected in SHC rats was blocked, indicating resistance to systemic bone inducing factor(s) of SHC rats in aged bone matrix. These results suggest that age-related decrease in responses to some systemic bone inducing factor may lead to the bone loss with advancing age.

A phase I/II study of a hypoxic cell radiosensitizer KU-2285 in combination with intraoperative radiotherapy

A fluorinated 2-nitroimidazole radiosensitizer KU-2285 was given before intraoperative radiotherapy (IORT) to 30 patients with unresectable, unresected or macroscopic residual tumours. Twenty-three patients had pancreatic cancer and five had osteosarcoma. The IORT dose was 30 Gy for unresectable pancreatic cancer and 60 Gy for osteosarcoma. The dose of KU-2285 administered ranged from 1 to 9 g m-2. Four patients received a dose of 9 g m-2, and ten received 6.8-7 g m-2. All patients tolerated KU-2285 well, and no drug-related toxicity was observed. The average tumour concentration of KU-2285 immediately after IORT was 166 microg g-1 at dose of 6.8-7 g m-2 and 333 microg g-1 at 9 g m-2. The average tumour-plasma ratio was > or = 0.82. Eleven patients with unresectable but localized pancreatic cancer treated with KU-2285 plus IORT and external beam radiotherapy had a median survival time of 11 months and 1-year local control rate of 50%, which compares favourably with those of 8 months (P = 0.26) and 28% (P = 0.10) for 22 matched historical control patients. The five patients with osteosarcoma attained local control. The results of this first study on KU-2285 and IORT appear encouraging, and further studies of this compound seem to be warranted.

Concealed left ventricular hypertrophy and diastolic dysfunction in hypertrophic cardiomyopathy in the presence of acute left ventricular volume overload. A case report

We report a patient in whom hypertrophic cardiomyopathy, with both left ventricular hypertrophy and diastolic dysfunction, was masked by acute severe aortic regurgitation and marked left ventricular dilation. Upon admission, 1) two-dimensional echocardiogram of the left ventricle revealed a dynamic and flail vegetation on the aortic right coronary cusp and marked left ventricular dilation, 2) a massive aortic regurgitant signal was recorded by color Doppler flow imaging, and 3) transmitral flow velocity by pulsed Doppler echocardiogram revealed a pseudonormalization. However, symmetric hypertrophy of the left ventricular wall, a decrease in early diastolic wave and a compensatory increase in atrial systolic wave of the transmitral flow velocity appeared after successful aortic valve replacement.

[Reoperation for malfunction of Ionescu-Shiley bovine pericardial bioprosthetic valves in the mitral position--special consideration with emergency operation]

Sixty-eight patients have had mitral valve replacement with Ionescu-Shiley bovine pericardial bioprosthesis from 1981 to 1984. Thirty five patients were required reoperation due to primary tissue failure of the bioprosthesis, 10 (28.6%) were on emergency basis and 25 (71.4%) were on elective. Hospital deaths were two (20.0%) on emergency and four (16.0%) on elective. Clinical features of emergency cases were as follows: progressive congestive heart failure in eight, severe hemolysis with massive hemoglobinuria in eight and acute renal failure in four. Cusp tears were observed in all valves, 8.1 +/- 1.5 mm in emergency group and 4.2 +/- 3.6 mm in elective group. Neointimal ingrowth over Dacron cloth of the inner surface of the stent was absent in 29 valves (89.2%). Calcification was observed in seven valves, however these were not dominant causes of primary tissue failure. Clinical symptoms were correlated with structural deterioration of explanted valves. Structural deterioration of the bioprosthesis may occur suddenly and progressively. Our experience demonstrated that life-threatening prosthetic valve failure may occur with a relatively high incidence and that careful follow-up is needed for Ionescu-Shiley bovine pericardial bioprosthesis.

Dissecting aneurysms of the anterior cerebral artery and accessory middle cerebral artery. Case report

A 66-year-old woman presented with dissecting aneurysms of the anterior cerebral artery (ACA) and accessory middle cerebral artery (MCA) manifesting as subarachnoid hemorrhage but without radiological evidence of the dissecting aneurysms. Intraoperative observation revealed that the vessel walls were dark purple in color, a typical finding of dissecting aneurysm. The abnormal A1 segment was trapped and the dissecting aneurysm of the accessory MCA was wrapped. In the case of SAH of unknown origin, dissecting aneurysm should always be kept in mind even if the angiogram does not show any abnormal finding. This is the first reported case of dissecting aneurysm of the accessory MCA.