Renal mineral handling in normal rats treated with sevelamer hydrochloride (Renagel), a noncalcemic phosphate binder

The effects of sevelamer hydrochloride (Renagel); hereafter referred to as sevelamer), a noncalcemic phosphate binder, on renal mineral handling were examined in rats. Normal rats were fed a diet containing 0.3, 1, 3, and 5% sevelamer for 8 days, and serum, urine, and the immunohistochemical localization of the type II Na/Pi cotransporter protein in the kidney were analyzed. Rats treated with 3 or 5% sevelamer showed significant decreases in serum phosphorus (P) and parathyroid hormone (PTH) levels, with no changes in serum calcium (Ca), magnesium (Mg), or 1,25(OH)2D3 levels. Increases were observed in urinary excretions of Ca and Mg associated with a reduction in the PTH level in rats treated with 3 or 5% sevelamer. Rats treated with 1% or higher concentrations of sevelamer showed significant dose-dependent and marked reductions of the urinary P excretion, and the tubular reabsorption of P was maximized to almost 100% in the 5% sevelamer group. The hypophosphaturia in rats treated with 3 or 5% sevelamer was accounted for by the reductions in serum PTH and P per se, and immunohistochemical analysis showed that the expression of type II Na/Pi cotransporter protein was markedly increased at the brush border membranes of the deep and superficial nephrons in rats treated with 5% sevelamer as compared with rats given a normal diet. In conclusion, sevelamer rapidly lowered serum P and PTH levels in normal rats. Sevelamer treatment also produced a marked hypophosphaturia associated with translocation of type II Na/Pi cotransporter protein and increased urinary Ca and Mg excretions by the reduction of PTH.

The (betaalpha)(8) glycosidases: sequence and structure analyses suggest distant evolutionary relationships

There are currently at least nine distinct glycosidase sequence families which are all known to adopt a TIM barrel fold [Henrissat,B. and Davies,G. (1997) CURR: Opin. Struct. Biol., 7, 637-644]. To explore the relationships between these enzymes and their evolution, comprehensive sequence and structure comparisons were performed, generating four distinct clusters. The first cluster, S1, comprises the alpha-amylase related enzymes, all with the retention mechanism (axial-->axial). The second cluster, S2, included two functional subgroups, one composed of various kinds of glucosidases all with the retention mechanism (equatorial-->equatorial) (the so-called 4/7 superfamily), and the other subgroup including the beta-amylases with the inversion mechanism (axial--> equatorial). The third cluster, S3, with the retention mechanism (equatorial-->equatorial), could be subdivided, based on the catalytic residues and mechanisms, into two functional subgroups: the chitinase group, catalysed by two acidic residues on the C-termini of beta-4 and beta-6, and the hevamine group, using two acidic residues on the C-termini of beta-4 for catalysis. The fourth cluster, S4, is composed of chitobiase with the retention mechanism (equatorial--> equatorial). These clusters are compared with the sequence families derived by Henrissat and coworkers. PSI-BLAST profiles and multiple-alignments of tertiary structures suggest that S1 and S2 are distantly related, as are S3 and S4, which have N-acetylated substrates. This work highlights the difficulties of untangling distant evolutionary relationships in ubiquitous folds such as the TIM barrel.

Coronary artery bypass grafting for patients with non-dialysis-dependent renal dysfunction (serum creatinine > or =2.0 mg/dl)

INTRODUCTION

Patients with renal dysfunction carry a risk of coronary atherosclerosis. The purpose of this study was to evaluate the outcome after coronary artery bypass grafting (CABG) in patients with decreased renal function (serum creatinine > or =2.0 mg/dl).

METHODS

We retrospectively analyzed consecutive patients who had undergone isolated CABG at Shin-Tokyo Hospital between May 1, 1991 and April 31, 2000. Preoperative, perioperative, and follow-up data of the non-dialysis-dependent patients with preoperative serum creatinine equal to or more than 2.0mg/dl (group R, n=59) were collected, and compared with those of the control patients (serum creatinine < 2.0, group C, n=1666). Group R was further divided into the off-pump and on-pump CABG group and their perioperative results were compared.

RESULTS

Group R included 51 males and eight females with a mean age of 66.4. The mean number of anastomoses was not significantly different between groups; however, clump time and pump time were longer in group R. Postoperative recovery was longer in group R than in group C, which is associated with a more frequent occurrence of major complications (28.8% in group R and 10.7% in group C, P<0.0001) and mortalities (6.8% in group R and 0.5% in group C, P<0.0005). The patients who underwent off-pump CABG experienced relatively faster recovery than those who underwent on-pump CABG, despite decreased renal function. At the mean follow-up of 2.4 years, the actuarial 3-year survival rate of groups R and C were 75.3 and 96.9%, respectively (P<0.0001), excluding hospital mortality. The actuarial 3-year cardiac event-free rate was 76.7% in group R and 87.3% in group C (P<0.05).

CONCLUSIONS

Patients with decreased renal function carry significant operative risks and require prolonged hospital care. Even after adequate surgical revascularization was completed, the long-term cardiac event-free and survival rates in the patients with renal dysfunction were inferior to the patients with normal renal function.

Sevelamer hydrochloride (Renagel), a non-calcaemic phosphate binder, arrests parathyroid gland hyperplasia in rats with progressive chronic renal insufficiency

BACKGROUND

It has been demonstrated that dietary phosphate restriction suppresses parathyroid hormone (PTH) secretion and parathyroid cell proliferation in experimental animals with chronic renal insufficiency (CRI) independently of serum calcium and 1,25(OH)(2)D3 levels. This study was conducted to examine whether sevelamer hydrochloride (Renagel); hereafter referred to as sevelamer), a non-calcaemic phosphate binder could inhibit the parathyroid gland (PTG) hyperplasia in rats with progressive CRI.

METHODS

Male Sprague-Dawley rats were injected twice with low doses of adriamycin (ADR). Two weeks after the last injection of ADR, rats were fed a diet containing 1 or 3% sevelamer for 84 days. Time course changes of serum levels of calcium, phosphorus, and PTH were measured. At the end of study, serum 1,25(OH)(2)D3 levels were measured and the maximal two-dimension area of the PTG in paraffin section was calculated using an imaging analyser.

RESULTS

Dietary sevelamer treatment inhibited the elevations of serum phosphorus, calciumxphosphorus product, and PTH levels that occurred as the study progressed. Sevelamer also suppressed maximal PTG area and there existed positive strong correlation between maximal PTG area and serum PTH levels at the end of the study. Serum phosphorus levels positively correlated well with serum PTH levels and maximal PTG area. In contrast, serum calcium or 1,25(OH)(2)D3 levels did not show any correlation with serum PTH levels and maximal PTG area.

CONCLUSIONS

Sevelamer treatment arrested hyperphosphataemia and PTG hyperplasia accompanied by the elevation of serum PTH levels. The correlation analysis suggests that reduced serum phosphorus levels contributed to the suppression of PTG hyperplasia and resulted in the reduction of PTH levels in this animal model after the sevelamer treatment. The management of phosphorus control started from early stage of CRI could prevent PTG hyperplasia and facilitate later management of secondary hyperparathyroidism.

[Compounds modulating parathyroid hormone (PTH) secretion]

The control of parathyroid hormone (PTH) secretion is strictly regulated by the parathyroid Ca receptor (CaR). Calcimimetics and calcilytics selectively act on the parathyroid CaR to inhibit and enhance PTH secretion, respectively. According to the recent pharmacological two-state model, calcimimetics act on the CaR as allosteric agonists to stabilize an active conformation of CaR. Conversely, calcilytics act on the CaR as allosteric inverse agonists to stabilize an inactive conformation of CaR. These compounds that can alter circulating levels of PTH and bone turnover might provide novel treatments for adynamic bone disease in patients with chronic renal failure.

Cloning of rodent megsin revealed its up-regulation in mesangioproliferative nephritis

BACKGROUND

We recently cloned a new human mesangium-predominant gene, megsin. Megsin is a novel member of the serine protease inhibitor (serpin) superfamily. To elucidate functional roles of this gene, we cloned megsin in rodents and investigated its role in a rat nephritis model.

METHODS

Megsin homologues were cloned from cultured rat and mouse mesangial cDNAs utilizing polymerase chain reaction (PCR) with degenerative primers. Expression of megsin in three different types of resident glomerular cells was investigated by PCR. Levels of megsin mRNA expression at various time points in the anti-Thy1 rat nephritis model were studied by semiquantitative PCR and Northern blotting analysis. In order to investigate megsin protein expression in anti-Thy1 nephritis rats, we raised antibody against rat megsin-specific synthetic peptide, with which immunohistochemical studies were performed.

RESULTS

Rat and mouse megsins were composed of 380 amino acids, which revealed 75.3 and 73.9% identity, respectively, with human megsin at the amino acid level. Characteristic features as an inhibitory serpin were conserved in both rat and megsin megsins. PCR analysis revealed expression of megsin in cultured mesangial cells but not in glomerular epithelial or endothelial cells. In anti-Thy1 nephritis rats, semiquantitative PCR and Northern blotting showed that expression of megsin mRNA was up-regulated in glomeruli at day 8. Immunohistochemical studies demonstrated the prominent accumulation of megsin in glomeruli at the same time point. Megsin was mainly localized in mesangial area. The megsin expression level returned to the basal level at day 28.

CONCLUSION

Sequences of megsin were well conserved among different species. Rat megsin was also predominantly expressed in mesangial cells. Expression of megsin was up-regulated at the peak of hypercellularity and matrix accumulation in the mesangioproliferative glomerulonephritis model, suggesting that megsin may participate in the process of glomerulosclerosis by modulating extracellular matrix deposition or cell survival.

Local Ca(2+) transients and distribution of BK channels and ryanodine receptors in smooth muscle cells of guinea-pig vas deferens and urinary bladder

1. The relationship between Ca(2+) sparks spontaneously occurring at rest and local Ca(2+) transients elicited by depolarization was analysed using two-dimensional confocal Ca(2+) images of single smooth muscle cells isolated from guinea-pig vas deferens and urinary bladder. The current activation by these Ca(2+) events was also recorded simultaneously under whole-cell voltage clamp. 2. Spontaneous transient outward currents (STOCs) and Ca(2+) sparks were simultaneously detected at -40 mV in approximately 50 % of myocytes of either type. Ca(2+) sparks and corresponding STOCs occurred repetitively in several discrete sites in the subplasmalemmal area. Large conductance Ca(2+)-dependent K(+) (BK) channel density in the plasmalemma near the Ca(2+) spark sites generating STOCs was calculated to be 21 channels microm(-2). 3. When myocytes were depolarized from -60 to 0 mV, several local Ca(2+) transients were elicited within 20 ms in exactly the same peripheral sites where sparks occurred at rest. The local Ca(2+) transients often lasted over 300 ms and spread into other areas. The appearance of local Ca(2+) transients occurred synchronously with the activation of Ca(2+)-dependent K(+) current (I(K,Ca)). 4. Immunofluorescence staining of the BK channel alpha-subunit (BKalpha) revealed a spot-like pattern on the plasmalemma, in contrast to the uniform staining of voltage-dependent Ca(2+) channel alpha1C subunits along the plasmalemma. Ryanodine receptor (RyR) immunostaining also suggested punctate localization predominantly in the periphery. Double staining of BKalpha and RyRs revealed spot-like co-localization on/beneath the plasmalemma. 5. Using pipettes of relatively low resistance, inside-out patches that included both clustered BK channels at a density of over 20 channels microm(-2) and functional Ca(2+) storage sites were obtained at a low probability of approximately 5%. The averaged BK channel density was 3-4 channels microm(-2) in both types of myocyte. 6. These results support the idea that a limited number of discrete sarcoplasmic reticulum (SR) fragments in the subplasmalemmal area play key roles in the control of BK channel activity in two ways: (i) by generating Ca(2+) sparks at rest to activate STOCs and (ii) by generating Ca(2+) transients presumably triggered by sparks during an action potential to activate a large I(K,Ca) and also induce a contraction. BK channels and RyRs may co-localize densely at the junctional areas of plasmalemma and SR fragments, where Ca(2+) sparks occur to elicit STOCs.

Coronary artery bypass grafting using the radial artery: midterm results in a Japanese institute

BACKGROUND

To avoid remote cardiac events associated with graft occlusions, arterial conduits are being increasingly utilized in coronary artery bypass grafting (CABG). The development of antispasmic agents has enabled the use of the radial artery as a graft conduit in CABG.

METHODS

Between December 1995 and December 1998, 920 consecutive isolated CABG operations were performed at Shin-Tokyo Hospital. The radial artery was used for graft conduits in 475 of these patients, and their data were analyzed in this study. The patients were followed to determine midterm graft patency, cardiac events, and survival. All data are given as mean +/- standard deviation. The end points were patient death or occurrence of cardiac events.

RESULTS

The radial artery was used in 475 patients (366 males and 109 females, with a mean age of 64.5+/-8.5 years). The left internal mammary artery was used in 94.9% of patients, the right internal mammary artery in 17.5%, the gastroepiploic artery in 50.9%, the inferior epigastric artery in 0.2%, and the saphenous vein in 39.2%. The in-hospital morbidity and mortality rates of the studied group were 12.8% and 0.6%, respectively. A major complication related to radial artery harvesting, compartment syndrome of the arm due to postoperative bleeding, was observed in 1 patient. No postoperative myocardial infarction attributable to radial artery bypass was observed. During the late follow-up period of 3.5+/-0.9 years, cardiac events were observed in 63 patients, giving actuarial 2- and 3-year event-free rates of 92.8% and 89.6%, respectively. A total of 24 late deaths were noted, including seven cardiac deaths, giving actuarial 2- and 3-year survival rates of 98.1% and 97.2%, respectively. Postoperative angiography was performed in selected patients. The cumulative graft patency rate of the radial artery was 93.0% during the mean angiographical follow-up period of 1.5+/-1.1 years.

CONCLUSIONS

No adverse effects were noted after CABG using a radial artery graft in this short- and midterm follow-up period.

A previous mastectomy does not increase sternal complications after coronary artery bypass grafting regardless of whether an internal mammary artery is used

A mastectomy for breast cancer may alter the selection of grafts or the postoperative outcomes after coronary artery bypass grafting (CABG). To clarify these points, a retrospective analysis of patients who underwent CABG after a mastectomy was undertaken. A total of 19 mastectomy patients (13 left, 6 right, and 1 bilateral mastectomy) were identified prior to CABG, and their perioperative data as well as late outcomes were examined. The studied group consisted of all females with a mean age of 68.8 +/- 6.2 years. The internal mammary artery (IMA) was used in 14 (73.7%) patients; however, there were no patients in whom bilateral IMAs were harvested. Among these 14 patients, an ipsilateral IMA was harvested in 6 and a contralateral IMA in 8. Alternative grafts were selected in 6 patients. A contralateral IMA or other graft conduits were utilized instead of an ipsilateral IMA. There were no in-hospital deaths or sternal wound complications. With a mean follow-up of 2.6 years, 3 patients died (1 cardiac death and 2 noncardiac deaths) and 1 patient developed angina due to de-novo coronary artery stenosis. In patients who have undergone a previous mastectomy, CABG using a single IMA is considered to be safe. If the IMA has good pulsation and if IMA harvesting is not difficult, even after a mastectomy, it can be used as a graft conduit without increasing the risk of sternal wound complications.

[New subjects for exceeding conventional on-pump CABG]

Coronary artery bypass grafting (CABG) used to be performed under cardiac arrest and cardiopulmonary bypass (CPB). During the last decade, efforts were made to minimize CPB-related complications. The technique of off-pump CABG (OPCAB) has been established during the last 5 years. Elimination of CPB and OPCAB has successfully reduced a number of perioperative complications and has provided early patient recovery. A compression type of coronary stabilizer was used early phase of OPCAB. Off-pump revascularization using the compression device was limited to the anterior wall of the heart. Bypass to the posterior wall under a beating heart was not popular until the suction type of stabilizer had become available. A suction device assisted by the Lima's pericardial suture allowed us to perform bypass grafting any aspects of the heart. Recently, we are skeltonizing the arterial grafts using the Harmonic scalpel. Applying skeltonizing technique to the radial artery or internal thoracic artery, we can successfully perform sequential grafting in selected cases. The number of distal anastomoses has been gradually increased as the device and technique were advanced (2.1 distal anastomoses with a compression device, 2.9 with a suction device, and 3.2 with the skeltonization technique). The frequency of the complete revascularization also increased. On the other hand, the complications associated with the procedure were comparable among these three off-pump methods, but were significantly fewer than on-pump CABG. Currently performed OPCAB can provide almost same number of distal anastomoses as on-pump CABG, with less frequency of postoperative mortality and morbidity, and with early patient recovery. These favorable results were attributed to the progress of the device and technique.

Coronary artery bypass grafting for hemodialysis-dependent patients

Patients with end-stage renal disease carry a risk of coronary atherosclerosis. This study was performed to evaluate the perioperative and remote data of coronary artery bypass grafting (CABG) in hemodialysis dependent patients. We retrospectively analyzed the results of isolated CABG performed at Shin-Tokyo Hospital between June 1, 1993 and May 31, 2000. Preoperative, perioperative, and follow-up data of the patients on hemodialysis (Group HD, n = 37) were collected and compared with those of control patients (Group C, n = 1,639). Group HD consisted of 26 males and 11 females with a mean age of 59.9 +/- 8.1 years, and the mean number of bypasses was 2.5 +/- 1.1. Group HD had a longer postoperative intubation time, ICU stay, and hospital stay than Group C. The postoperative major complication rate in Group HD (18.9%) was not significantly different from that in Group C (11.3%). However, the inhospital mortality rate in Group HD (5.4%) was higher than Group C (0.6%). At the mean follow-up of 2.4 years, the actuarial 3-year survival of Groups HD and C were 90.6% and 97.6%, respectively (p < 0.001), excluding hospital mortality. The actuarial 3-year cardiac event-free rates were 84.3% in Group HD and 88.8% in Group C, showing no difference. Patients on chronic hemodialysis carry a significant risk of prolonged inhospital care and hospital death. Once successful surgical revascularization was completed, their long-term cardiac events could be controlled as effectively. The increased distant death rates was probably associated with the nature of renal disease.

Changes in quantitative profile of extracellular matrix components in the kidneys of rats with adriamycin-induced nephropathy

Extracellular matrix components (ECMs) in histological sections of the kidney cortex from the rats with adriamycin (ADR)-induced nephropathy (5 mg/kg, i.v.) were quantified by an immunohistochemical micromethod. Changes in kidney histopathology and urine and blood biochemistry were investigated. Enlarged kidneys were granular on the surface and pale in color in ADR-treated rats, and these rats had kidneys with glomeruli with expanded mesangial area and with capillary aneurysm. Severe albuminuria, hypoalbuminemia, hypercholesterolemia and disorders in other nephrotic parameters were observed in ADR-treated rats. Type I and IV collagens, fibronectin and laminin contents in the renal cortex of ADR-treated rats at 10 weeks were 329, 317, 263 and 295%, respectively, higher than in each vehicle control, and those at 28 weeks were 1,211, 930, 1,057 and 1,012%, respectively. The glomerular sclerotic abnormalities progressed in a time-dependent manner. Moreover, there was a strong correlation between the ECM levels and serum creatinine and blood urea nitrogen levels. In conclusion, microquantification provided useful information for accurate diagnosis and prognosis of nephrotic lesions and is a good tool to assess the advancement of renal disorders in patients with nephropathy.

Off-pump coronary artery bypass. Mid-term results

OBJECTIVES

Off-pump coronary artery bypass grafting (CABG) on the beating heart has become popular procedure in cardiac surgery and its initial results appeared favorable. We report our early and mid-term results of off-pump CABG performed at Shin-Tokyo Hospital.

METHODS

Medical records of patients undergoing off-pump or conventional on-pump CABG from September 1, 1996, to August 31, 1999 were retrospectively reviewed. Patients underwent off-pump CABG were further classified into 2 groups; MIDCAB (Off-pump CABG for single vessel revascularization via a small skin incision) and OPCAB (off-pump CABG mainly approached via midline sternotomy) group. Their preoperative, perioperative, and follow-up data were collected and analyzed.

RESULTS

Among a total of 995 cases of CABG, 194 cases were off-pump CABG (male/female 142/52, mean age 66.9). The mean number of distal anastomoses in off-pump CABG was 1.9 +/- 0.9 (1.0 +/- 0.0 in MIDCAB and 2.3 +/- 0.7 in OPCAB), which was significantly fewer than in on-pump CABG (3.6 +/- 1.1), with p < 0.0001. Intubation time (5.3 +/- 5.7 hours in off-pump CABG vs 13.1 +/- 24.2 hours in on-pump CABG), ICU stay (1.7 +/- 1.1 vs 3.2 +/- 3.0 days), and postoperative hospital stay (14.0 +/- 7.9 vs 18.1 +/- 12.1 days) in off-pump CABG were significantly shorter than in on-pump CABG (p < 0.0001). In the off-pump CABG group, there were no in-hospital deaths and 14 major complications, fewer than in on-pump CABG (8 hospital deaths and 114 major complications). Postoperative angiography before hospital discharge was conducted in 80 patients (41.2%) and showed 2 occlusions, giving a graft patency rate of 98.6% in the off-pump group. During follow-up (0.9 +/- 0.6 year) period, there were 5 non-cardiac deaths and 20 cardiac events in the off-pump group. The actuarial survival rate at 36 months was 94.6% for off-pump CABG, showing no significant difference from the rate for conventional CABG patients (95.2% at 36 month, p = NS) The event-free rate was 84.0% at 36 months in off-pump CABG patients; however, which was less favorable than on-pump CABG patients (88.0% at 36 months, p < 0.05).

CONCLUSIONS

Both in-hospital and mid-term results for off-pump CABG patients were acceptable. Isolated CABG can thus be safely performed without cardiopulmonary bypass. Advances in coronary stabilization have contributed to these improved results. The observed long-term cardiac events may be related to incomplete revascularization.

Clusterin is up-regulated in glomerular mesangial cells in complement-mediated injury

BACKGROUND

Clusterin is a soluble complement regulatory protein that binds to C5b-7 and inhibits generation of membrane attack complex, C5b-9. Glomerular deposition of clusterin has been observed in human and experimental membranous nephropathy in association with C5b-9 and immune deposits. However, it is controversial as to whether clusterin observed in glomeruli is synthesized by the resident glomerular cells or is derived from the circulation. We examined whether clusterin is expressed by resident glomerular cells exposed to complement-mediated injury.

METHODS

In vitro, cultured mesangial cells were exposed to antithymocyte serum immunoglobulin G and 5% normal rat serum as a complement source. In vivo, we induced anti-Thy1 nephritis in rats and examined the kidneys on days 8 and 29.

RESULTS

We observed increased expression of clusterin in cultured rat glomerular mesangial cells stimulated by sublytic complement attack. We also demonstrated that in comparison with control rats, both a marked increase in clusterin mRNA in the glomeruli and marked deposition of clusterin protein in the mesangial area occurred in the OX-7-treated rats on day 8 in association with C5b-9 deposition and on day 29.

CONCLUSION

Clusterin was induced in glomerular mesangial cells during the course of immune-mediated injuries. This up-regulation of clusterin may play a critical role in protecting mesangial cells from complement attack.

Effects of chitosan-coated dialdehyde cellulose, a newly developed oral adsorbent, on glomerulonephritis induced by anti-Thy-1 antibody in rats

The effects of chitosan-coated dialdehyde cellulose (chitosan DAC), a newly developed oral adsorbent for urea and ammonia, were examined in a glomerulonephritis model in rats. Mesangial proliferative glomerulonephritis accompanied with proteinuria was induced by an intravenous injection of anti-rat Thy-1.1 monoclonal antibody (OX-7). The proliferation of mesangial cells and an accumulation of extracellular matrix components such as type I collagen and fibronectin were observed in the glomeruli 9 days after OX-7 injection; these were improved in rats fed a diet containing chitosan DAC (10% content) for 9 days compared with those in rats fed a normal diet. Chitosan DAC treatment decreased the elevated urinary protein and blood urea nitrogen at days 8-9 to the normal levels; the increased fecal excretion of nitrogen might participate in this phenomenon. In addition, chitosan DAC treatment showed an increase in fecal water content associated with a decrease in urinary volume. These therapeutic effects may be due to the reduction of proteinic factor expression and the compensational function of chitosan DAC for kidney. These results suggest that chitosan DAC treatment may be useful for ameliorating mesangial proliferative glomerulonephritis.

Ruptured aortic dissecting aneurysm in Turner's syndrome: a case report and review of literature

Cardiovascular malformations are frequently observed in Turner's syndrome. Bicuspid aortic valve and coarctation of the aorta are commonly associated with Turner's syndrome whereas aortic dissection is rare but its rupture results in death. We experienced a case of ruptured dissecting aneurysm (Stanford type A) in a 30-year-old female with Turner's syndrome. Emergent total arch replacement was performed successfully. A literature review revealed 32 cases of aortic dissection in patients with Turner's syndrome, including 15 cases of rupture. However, survival after rupture was reported only two cases. To our knowledge, this report descries the third known case of successful surgical management of ruptured aortic dissection in Turner's syndrome.

Coronary artery bypass grafting in the elderly

BACKGROUND AND METHODS

The incidence of coronary artery bypass grafting (CABG) in elderly patients has been increasing. We retrospectively analyzed the results of CABG performed at Shin-Tokyo Hospital between January 1, 1991, and December 31, 1998. Preoperative, perioperative, and follow-up data of patients > or = 75 years old (group E, n = 190) were collected, and compared with those of patients < 75 years old (group Y, n = 1,380).

RESULTS

Female gender, emergent CABG, preoperative balloon pumping use, cardiogenic shock, hypertension, and preoperative cerebral vascular accident were significantly more frequent in group E (p < 0.05). CABG was completed without any significant differences, except for less frequent use of the bilateral internal mammary artery (p < 0.01), more frequent use of the saphenous vein (p < 0.005), and a greater incidence of blood transfusion in group E (p < 0.0001). The postoperative course required longer intubation, ICU stay, and postoperative hospital stay in group E (p < 0.001), and was more frequently associated with major complication (p < 0.0001) and in-hospital death (p < 0.05). During the mean follow-up of 2.7 years (maximum 6.9 years), the actuarial 5-year survival of groups E and Y were 84.3% and 92.5% (p < 0.01), respectively, excluding in-hospital mortality. The actuarial 5-year cardiac event-free rates were 79.9% in group E and 79.7% in group Y, showing no significant difference.

CONCLUSIONS

CABG in the elderly carries certain surgical risks. However, the long-term cardiac event-free rate after CABG in the elderly was almost the same as that of younger patients. Inferior long-term survival in the elderly was most likely due to the biological nature of aging.

Characteristic changes in carbohydrate profile in the kidneys of hereditary nephrotic mice (ICGN strain)

The ICR-derived glomerulonephritis (ICGN) mice consist of heterozygous and homozygous groups and are considered to be a good model for human idiopathic nephrotic syndrome. To reveal changes in cell-surface carbohydrate construction, 24 lectins were applied to kidney sections of 10-, 30- and 50-week-old male heterozygous and homozygous ICGN mice and age-matched male ICR mice. Bandeiraea simplicifolia lectin-I (BSL-I), which specifically binds to alpha-D-galactopyranosyl groups, showed positive staining in the glomeruli of ICGN mice, but not in those of ICR mice. Positive BSL-I staining was observed only in distal tubules of homozygous ICGN mice. Lectin blotting for BSL-I demonstrated characteristic glycoproteins (45, 58 and 64 kD) in ICGN but not in ICR mice, and the levels of these molecules augmented in homozygous ICGN mice with the progression of renal failure. Moreover, succinylated wheat germ agglutinin, Dolichos biflorus agglutinin, Aleuria aurantia lectin and Ulex europaeus agglutinin-I showed positive staining only in the glomeruli of homozygous ICGN mice, but not in those of heterozygous ICGN or ICR mice. The staining intensities of Ricinus communis agglutinin-I, Phaseolus vulgaris agglutinin-E and -L, Lens culinaris agglutinin and Erythrina cristagalli agglutinin (ECL) in the glomeruli of homozygous ICGN mice were stronger than those of heterozygous ICGN and ICR mice. In conclusion, lectin histochemistry provided useful information for the diagnosis and prognosis of nephrotic lesions. Characteristic BSL-I binding glycoproteins may be pathogenic factors which cause renal disease in ICGN mice and are good tools to investigate the molecular mechanism of renal disorders in ICGN mice.

Off-pump coronary artery bypass: early results

BACKGROUND

Coronary artery bypass grafting (CABG) on a beating-heart has gained the attention of cardiac surgeons and shown favorable initial results. However, only a few follow-up results have been reported. We report herein our one-year experiences of off-pump CABG performed at Shin-Tokyo Hospital.

METHODS

Retrospective chart review was performed for patients who underwent off-pump CABG and conventional isolated CABG between 01/01/98 and 12/31/98. Preoperative, perioperative, and follow-up data were collected.

RESULTS

Among 315 cases of isolated CABG, 94 cases were off-pump CABG (male/female 69/25, mean age 67.7). Mean number of distal anastomoses performed by off-pump CABG was 1.7 +/- 0.7 (42 cases of single-vessel revascularization and 52 cases of more than double- vessel revascularization). In off-pump CABG, there were no hospital deaths and 6 major complications including 2 incidences of perioperative myocardial infarction. Postoperative angiography before hospital discharge was performed in 56 patients (59.6%, 98 anastomosis) and revealed 5 occlusions, giving a graft patency rate of 94.9%. During the follow-up (11.4 +/- 4.1 months), there was 1 late non-cardiac death and 11 cardiac events. The event-free rate at 18 months was 94.0% in off-pump CABG, showing no significant difference from the event-free rate after conventional CABG (94.0% at 18 months, p = 0.135). Follow-up angiography was performed in 21 patients (33 anastomoses) at a mean interval of 3.6 months and showed 4 graft occlusions, giving a patency rate of 92.7%.

CONCLUSION

Both hospital and early results of off-pump CABG were acceptable. Off-pump CABG can be safely performed in selected patients.

Daily intermittent decreases in serum levels of parathyroid hormone have an anabolic-like action on the bones of uremic rats with low-turnover bone and osteomalacia

The calcium receptor agonist (calcimimetic) compound NPS R-568 causes rapid decreases in circulating levels of parathyroid hormone (PTH) in rats and humans. We hypothesized that daily intermittent decreases in serum PTH levels may have different effects on bone than do chronically sustained decreases. To test this hypothesis, we compared two NPS R-568 dosing regimens in rats with chronic renal insufficiency induced by two intravenous injections of adriamycin. Fourteen weeks after the second adriamycin injection, creatinine clearance was reduced by 52%, PTH levels were elevated approximately 2.5-fold, and serum 25(OH)D3 and 1,25(OH)2D3 levels were reduced substantially. Treatment by daily per os gavage, which decreased PTH levels intermittently, or continuous subcutaneous infusion, which resulted in a sustained suppression of serum PTH levels, then began for 8 weeks. Despite the hyperparathyroidism, the adriamycin-injected rats developed a low-turnover bone lesion with osteomalacia (fourfold increase in osteoid volume in the proximal tibial metaphysis) and osteopenia (67% decrease in cancellous bone volume and an 18% reduction in bone mineral density at the distal femur). Daily administered (but not infused) NPS R-568 significantly increased cancellous bone volume solely by normalizing trabecular thickness, and increased femoral bone mineral density by 14%. These results indicate that daily intermittent, but not sustained, decreases in PTH levels have an "anabolic-like" effect on bones with a low-turnover lesion in this animal model of chronic renal insufficiency.

Surgical management of unstable patients in the evolving phase of acute myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) can be treated with thrombolysis or coronary catheter intervention; surgical treatment--coronary artery bypass grafting (CABG)--is reserved for the patients in whom other procedures have failed. We performed CABG in 47 patients during the evolving phase of AMI, and analyzed their short-term and long-term results.

METHODS

Preoperative, intraoperative, and postoperative data were analyzed in patients who underwent emergency CABGs for AMI between January 1, 1992, and July 31, 1998. CABGs performed more than 7 days after AMI were excluded from this study.

RESULTS

The subjects were 47 patients (33 males and 14 females) with AMI who were treated by emergency CABG. Intraaortic balloon pumping was used in 44 cases and percutaneous circulatory pulmonary support was used in 3 cases. The mean interval between the onset of AMI and surgery was 27.4 +/- 27.9 hours. The mean number of bypass grafts was 3.0 +/- 1.1, and at least 1 arterial conduit was used in 45 cases (95.7%). Aortic clamp time, pump time, and operative time were 64.7 +/- 31.7, 117.3 +/- 55.2, and 313.2 +/- 84.8 minutes, respectively. IABP or percutaneous cardiopulmonary support were removed in the intensive care unit (ICU) 30.0 +/- 28.9 hours after CABG. The patients were extubated 41.4 +/- 40.5 hours after surgery, remained in ICU for 4.7 +/- 2.7 days, and were discharged from the hospital after 27.0 +/- 22.5 days. Three patients died from multiorgan failure related to postoperative sepsis, and 8 cases of major complications were observed. The actuarial 5-year survival rate of the patients treated with CABG was 83.0%.

CONCLUSIONS

Surgical treatment in the unstable patients after AMI can be performed with acceptable risk. Arterial revascularization may contribute to improvement in long-term results.

Coronary artery bypass grafting in patient with malignant neoplasm. Efficacy of coronary artery bypass grafting on beating heart

OBJECTIVE

Coronary artery bypass grafting (CABG) prior to noncardiac major surgery has effectively decreases short- and long-term mortality related to coronary ischemia. Coronary artery bypass on the beating heart is conducted to avoid the risk of cardiopulmonary bypass and it has contribute to shorten recovery time.

METHODS

Subjects were 19 patients with malignant neoplasm for whom a retrospective chart review was made between Jan. 1, 1992 and July 31, 1998. In the early phase of this study, between Jan. 1, 1992, and Dec. 31, 1997, CABG was performed using cardiopulmonary bypass, and late phase, between Jan. 1, 1998, and July 1, 1998, CABG was done on the beating heart without cardiopulmonary bypass.

RESULTS

Conventional CABG was performed in 12 patients with neoplasms (10 male and 2 female, age 64.7 +/- 6.1 years), and CABG on the beating heart was performed in 7 patients (6 male and 1 female, age 68.0 +/- 7.5 years). Fewer number of bypass grafts were made in the beating-heart CABG group (1.3 +/- 0.5 in beating-heart CABG versus 3.9 +/- 1.1 in conventional CABG). No cardiac events occurred in either group during the surgery for malignant tumors. The operative interval between CABG and cancer surgery was significantly shorter in the beating-heart CABG group (21.8 +/- 17.9 days in beating-heart CABG versus 53.5 +/- 42.9 days in conventional CABG, p < 0.05).

CONCLUSION

Patients with severe coronary artery disease and malignant neoplasms should undergo coronary artery revascularization before the neoplasm is treated. CABG on the beating-heart was safe and effective procedure in those with malignant neoplasms.

Calcimimetic NPS R-568 prevents parathyroid hyperplasia in rats with severe secondary hyperparathyroidism

Calcimimetic NPS R-568 prevents parathyroid hyperplasia in rats with severe secondary hyperparathyroidism.

BACKGROUND

Secondary hyperparathyroidism (secondary HPT) in chronic renal insufficiency (CRI) is characterized by multiglandular hyperplasia.

METHODS

In this study, we investigated the effects of the calcimimetic NPS R-568 on the parathyroid gland in rats with CRI induced by ligation of the renal arteries and severe secondary HPT induced by dietary phosphorus loading. Six days after surgery, high-phosphorus diet feeding was started, and NPS R-568 was administered to the rats for 56 days either by daily gavage (30 or 100 micromol/kg) or by continuous subcutaneous infusion (20 micromol/kg. day).

RESULTS

After 54 days, serum PTH levels in vehicle-treated CRI rats were 1019 vs. 104 pg/mL in sham-operated controls. Infusion of NPS R-568 maintained serum PTH at levels comparable with those of sham-operated controls, whereas daily gavage also prevented much of the increase in CRI controls and decreased PTH levels intermittently in a dose-dependent fashion. Parathyroid gland enlargement was caused predominantly by hyperplasia. Total cell number per kg body wt was 3.5-fold higher in vehicle-treated CRI rats than in sham-operated controls. Both infusion and high-dose gavage of NPS R-568 completely prevented the increase in parathyroid cell number.

CONCLUSION

These results demonstrate that the calcimimetic compound NPS R-568 can prevent both the increase in serum PTH levels and parathyroid hyperplasia in rats with CRI and severe secondary HPT. Moreover, these changes occurred despite decreases in serum 1, 25(OH)2D3 and increases in serum phosphate, suggesting a dominant role for the calcium receptor in regulating parathyroid cell proliferation.

Emergency off-pump coronary artery bypass grafting under a beating-heart

BACKGROUND

Coronary artery bypass grafting (CABG) on a beating heart has been successfully performed for high risk patients, and is known to be less invasive than conventional CABG using cardiopulmonary bypass (CPB). We expanded the indication of beating-heart CABG in patients requiring emergency coronary revascularization.

METHODS

A retrospective chart review was performed for patients who had undergone emergency CABG on a beating heart (EM-BH group), elective CABG on a beating heart (Elective-BH group) and emergency CABG under CPB (EM-CPB group), between January 1, 1997 and June 30, 1998.

RESULTS

Four cases (1 male and 3 females with a mean age of 67.8 +/- 5.4) in the EM-BH group, 67 cases (48 males and 19 females with mean age of 67.3 +/- 7.8) in the Elective-BH group, and 41 cases (29 males and 12 females with mean age of 63.3 +/- 10.4) in the EM-CPB group were analyzed. The number of the grafts was 1.75 +/- 0.50 in EM-BH group, 1.37 +/- 0.55 in the Elective-BH group, and 2.95 +/- 1.07 in the EM-CPB group. The intubation period, ICU stay, and the postoperative hospital stay were significantly shorter in the EM-BH group (6.0 hours intubation, 1.5 days ICU stay, and 11.5 days postoperative hospital stay) and Elective-BH group (6.8 +/- 11.0 hours intubation, 1.6 +/- 1.5 days ICU stay, and 12.7 +/- 5.2 days postoperative hospital stay) than in the EM-CPB group (20.1 +/- 22.5 hours intubation, 3.6 +/- 2.4 days ICU stay, and 21.8 +/- 14.9 days postoperative hospital stay).

CONCLUSION

The postoperative recovery period for EM-BH patients was almost the same as that for elective cases of beating-heart CABG, and was significantly shorter than that of conventional emergency CABG under CPB. Selected patients with coronary ischemia can be safely treated by beating-heart surgery.