Association between glomerular filtration rate and plasma N-terminal pro-atrial natriuretic peptide concentration in dogs.

OBJECTIVES: To investigate the association between plasma N-terminal pro-atrial natriuretic peptide concentration and glomerular filtration rate in dogs. MATERIALS AND METHODS: Dogs were classified into four categories by bodyweight. Dogs were divided into four groups (Groups 1 to 4) based on glomerular filtration rate estimates using plasma iohexol clearance per bodyweight category. Generalised linear models were built to explore the relationship between plasma N-terminal pro-atrial natriuretic peptide concentration and glomerular filtration rate and the effect of confounders on plasma N-terminal pro-atrial natriuretic peptide concentration. RESULTS: Fifty-three dogs were included (Group 1, 25; Group 2, seven; Group 3, five; and Group 4, 16). The medians (interquartile range) N-terminal pro-atrial natriuretic peptide concentrations for Groups 1 to 4 were 7224 pg/mL (4766 to 10,254 mg/dL), 8958 pg/mL (4935 to 11,271 mg/dL), 9280 pg/mL (9195 to 10,384 mg/dL) and 12,683 pg/mL (9133 to 19,217 mg/dL), respectively. Group 4, estimated to have the highest reduction in glomerular filtration rate, had a higher plasma N-terminal pro-atrial natriuretic peptide concentration than Groups 1 to 3. Based on the final generalised linear model, influencing factors for plasma N-terminal pro-atrial natriuretic peptide concentration were plasma iohexol clearance (-0.136; 95% confidence interval, -0.227 to -0.046) and bodyweight (-0.058; 95% confidence interval, -0.098 to -0.018). CLINICAL SIGNIFICANCE: N-terminal pro-atrial natriuretic peptide concentration is associated with the glomerular filtration rate.

Dynamic localization and function of Bni1p at the sites of directed growth in Saccharomyces cerevisiae.

Formin homology (FH) proteins are implicated in cell polarization and cytokinesis through actin organization. There are two FH proteins in the yeast Saccharomyces cerevisiae, Bni1p and Bnr1p. Bni1p physically interacts with Rho family small G proteins (Rho1p and Cdc42p), actin, two actin-binding proteins (profilin and Bud6p), and a polarity protein (Spa2p). Here we analyzed the in vivo localization of Bni1p by using a time-lapse imaging system and investigated the regulatory mechanisms of Bni1p localization and function in relation to these interacting proteins. Bni1p fused with green fluorescent protein localized to the sites of cell growth throughout the cell cycle. In a small-budded cell, Bni1p moved along the bud cortex. This dynamic localization of Bni1p coincided with the apparent site of bud growth. A bni1-disrupted cell showed a defect in directed growth to the pre-bud site and to the bud tip (apical growth), causing its abnormally spherical cell shape and thick bud neck. Bni1p localization at the bud tips was absolutely dependent on Cdc42p, largely dependent on Spa2p and actin filaments, and partly dependent on Bud6p, but scarcely dependent on polarized cortical actin patches or Rho1p. These results indicate that Bni1p regulates polarized growth within the bud through its unique and dynamic pattern of localization, dependent on multiple factors, including Cdc42p, Spa2p, Bud6p, and the actin cytoskeleton.

Purification of a cytosolic factor from rat liver that stimulates transcription in isolated nuclei and its action on purified RNA polymerase II-DNA system.

A cytosolic factor that stimulates transcription in isolated nuclei was purified approximately 4000-fold to near homogeneity from rat liver. The molecular weight of the factor was determined as 47 000 by SDS-polyacrylamide gel electrophoresis. The factor had no detectable deoxyribonuclease and protease activity but showed ribonuclease inhibitor activity. The factor could stimulate transcription in isolated nuclei by 50% at about 3.0 ng and the maximal stimulation was about 100%. When [gamma-S]ATP and [gamma-S]GTP were included in the reaction, the factor stimulated the synthesis of RNA which was able to bind to a mercury-Sepharose column and about 80% of the bound RNA was sensitive to a low concentration of alpha-amanitin. When heparin was added before initiation to preincubation mixture containing RNA polymerases II and DNA, a small but definite incorporation of [14C]UTP was observed. The factor alone had no stimulatory effect on the heparin-resistant incorporation of [14C]UTP but, in the presence of two rat liver nuclear fractions, phosphocellulose 0.5 and 1 M KCl step fractions, could stimulate the incorporation above the level with the combination of the two nuclear fractions. Antibody raised against the factor inhibited accurate transcription from the adenovirus 2 major late promoter in a nuclear lysate from Ehrlich ascites tumor cells, and the inhibition was neutralized by the factor.

Counterproductive effects of sodium bicarbonate in diabetic ketoacidosis.

Although a growing body of evidence supports that alkali therapy in diabetic ketoacidosis (DKA) might be counterproductive, our knowledge about the consequences of this treatment on ketone metabolism is limited. Consequently, we performed clinical and animal studies to further examine this topic. The clinical studies assessed seven patients with DKA treated with continuous insulin infusion at a low dosage. Three of them also received sodium bicarbonate (NaHCO3), whereas the remaining four acted as controls. The group receiving NaHCO3 showed a 6-h delay in the improvement of ketosis as compared with controls. In addition, there was an increase in acetoacetate (AcAc) levels during alkali administration, followed by an increase in 3-hydroxybutyrate (3-OHB) level after its completion. Significant differences were not found between groups in the response of plasma glucose to the overall therapy. The animal study examined the effects of a NaHCO3-rich perfusate on the hepatic production of ketones with the in situ rat-liver preparation. Alkali loading resulted in an immediate increase in the AcAc level followed by increases in both the 3-OHB level and the 3-OHB/AcAc ratio after its completion. Hepatic ketogenesis increased even further, to about twice the basal level, after termination of the NaHCO3 loading. This investigation confirms that alkali administration augments ketone production and unravels an effect of bicarbonate infusion that promotes a selective build up of AcAc in body fluids. The data support that alkali therapy in DKA has nonsaltuary effects in the metabolism and plasma levels of ketones.

Pharmacologic intervention for ischemic brain edema after retrograde cerebral perfusion.

Retrograde cerebral perfusion has recently been the focus of interest as a simple new technique of brain protection during aortic arch operations. We undertook the experimental protocol of 120 minutes of retrograde cerebral perfusion followed by antegrade reperfusion. Eighteen mongrel dogs were used. Retrograde cerebral perfusion was maintained at a flow rate of 150 to 250 ml/min to keep the perfusion pressure from 15 to 25 mm Hg. Animals were divided into three groups as follows: in group I, no treatment was received during and after retrograde cerebral perfusion; in group II, mannitol (2 gm/kg) was administered before cardiopulmonary bypass was restarted; and in group III, antivasospastic substance (1,2-bis nicotinamido]-propane) was continuously injected during and after retrograde cerebral perfusion (1 mg/kg per minute). Cerebral blood flow decreased during retrograde cerebral perfusion in all three groups. Cerebrovascular resistance showed marked increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with the values in groups II and III (group I: 3.35 +/- 0.73 and 5.00 +/- 1.57 mm Hg/ml per 100 gm per minute; group II: 1.30 +/- 0.33 and 1.03 +/- 0.17 mm Hg/ml per 100 gm per minute; group III: 1.24 +/- 0.41 and 0.98 +/- 0.24 mm Hg/ml per 100 gm per minute). The oxygen extraction level was reduced by cooling, but it rose to a higher level as a result of significant desaturation of returned blood even in deep hypothermia during retrograde cerebral perfusion. Both cerebral metabolic rate of oxygen and cerebral metabolic rate of glucose remained at low levels during retrograde cerebral perfusion. Ratios of cerebral blood flow to cerebral metabolic rate of oxygen and cerebral blood flow to cerebral metabolic rate of glucose were markedly reduced during retrograde cerebral perfusion. Intracranial pressure showed significant increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with values in group II or group III (group I: 22.7 +/- 2.8 and 20.6 +/- 5.1 mm Hg; group II: 6.3 +/- 1.8 and 5.3 +/- 1.3 mm Hg; group III: 4.2 +/- 1.7 and 7.7 +/- 2.8 mm Hg). Water content of the brain tissue in group I (77.54% +/- 0.29%) was significantly higher than that in group II (74.71% +/- 0.76%) or group III (74.14% +/- 0.48%). These data suggest that the supply of oxygen or glucose by retrograde cerebral perfusion is not enough to maintain sufficient cerebral metabolism, which may cause brain edema during antegrade reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Single lung transplantation for canine pulmonary hypertension.

BACKGROUND: In spite of recent reports of the clinical application of single lung transplantation for pulmonary hypertension, there is little underlying experimental data because of the lack of a reliable animal pulmonary hypertensive transplant model. We have established a pulmonary hypertensive model in beagles with dehydromonocrotaline and have been able to measure cardiopulmonary hemodynamics accurately and use circulatory assists during procedures. The purpose of this study was to determine whether single lung transplantation could be performed after the protocol of clinical procedure. METHODS AND RESULTS: In six control dogs, allografting was successfully completed without cardiopulmonary bypass. Because one pulmonary hypertensive recipient dog died of right ventricular failure during the procedure without cardiopulmonary bypass, we used bypass for allografting in five pulmonary hypertensive dogs. Cardiopulmonary bypass lowered pulmonary artery pressure, allowing pulmonary arterial clamping and avoiding right ventricular overload. All pulmonary hypertensive dogs undergoing bypass were successfully weaned from bypass, indicating a good hemodynamic response to transplantation. In pulmonary hypertensive dogs, transplantation resulted in significant decreases in systolic pulmonary artery pressure and pulmonary vascular resistance, and a significant increase in blood flow to the graft lung, whereas in controls the results were the reverse. CONCLUSIONS: Thus we were able to show that hemodynamics improved after single lung transplantation with cardiopulmonary bypass in a new pulmonary hypertensive animal model. These relatively larger animals are valuable for further studies of single, double, bilateral, and heart-lung transplantation for pulmonary hypertension.

Early results of coronary grafting using ultrasonically skeletonized internal thoracic arteries.

BACKGROUND: We have developed an ultrasonic complete skeletonization technique for obtaining internal thoracic artery (ITA) grafts and have used this method clinically since January 1998. In this report, we discuss the early results of bilateral ITA grafts obtained with our method. METHODS: We studied 200 consecutive patients who underwent coronary artery bypass grafting using ITAs obtained by this technique. Angiography of the grafts was performed in 188 patients (94%) within 1 month after coronary artery bypass grafting. RESULTS: The ITA grafts were about 4 cm longer than pedicled ITA grafts. The free flow through the grafts was at least 30% higher than through pedicled ITAs. The early patency rate determined by postoperative angiography of the grafts was 99.7% for left ITAs and 100% for right ITAs. No patient required postoperative intervention or repeated surgery. CONCLUSIONS: Ultrasonic complete skeletonization increases the effective length of ITA bypasses, improves free flow through the bypasses, and it is less invasive than conventional pedicled harvesting. These excellent early results indicate that this technique is a straightforward, safe, less invasive, and optimal method for obtaining ITA bypass grafts.

Retrograde cerebral perfusion versus selective cerebral perfusion as evaluated by cerebral oxygen saturation during aortic arch reconstruction.

BACKGROUND: Time limits for neuroprotection by retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP) in aortic arch aneurysm repair or dissection are undergoing definition. METHODS: Using near-infrared optical spectroscopy, changes in regional cerebrovascular oxygen saturation (rSO2) were compared between the two perfusion methods. RESULTS: Immediately before cardiopulmonary bypass, baseline rSO2 was 63.9%+/-6.9% for the RCP and 66.1%+/-5.3% for the SCP group (no significant difference). As patients were core-cooled to 20 degrees C, rSO2 increased to 73.1%+/-8.8% and 74.1%+/-7.9% in the RCP and SCP groups, respectively. With circulatory arrest, rSO2 suddenly decreased. After starting cerebral perfusion, rSO2 returned to prearrest values in the SCP group but continued decreasing steadily in the RCP group, to levels below baseline after about 25 minutes. At the end of perfusion, rSO2 was 57.4%+/-12.2% for the RCP group and 71.7%+/-6.9% for the SCP group, and the ratio of rSO2 to baseline value was 0.89 for RCP and 1.08 for SCP despite a shorter brain perfusion time for RCP (38.8+/-18.0 versus 103.3+/-43.3 minutes). Three of 5 patients whose ratios of rSO2 to baseline at the end of brain protection were 0.7 or less had neurologic deficits. CONCLUSIONS: Although SCP showed no clinically important time limitation, rSO2 continued to decrease with time during RCP. An rSO2 ratio less than 0.7 could represent a critical lower limit.

Techniques used by elite long jumpers in preparation for takeoff.

It was hypothesized that some characteristics of the positions adopted by long jumpers during the final strides of the approach are significantly related to the distance of the jump, and that they are so related only by virtue of their relationships with the horizontal velocity at touchdown and/or the vertical velocity at takeoff. Trials by 20 male and 26 female long jumpers were recorded cinematographically and subsequently analyzed. The takeoff distance for the fourth-last stride, the landing distance for the last stride, and the height of the center of gravity (CG) at takeoff into the jump were significantly correlated with the distance of the jump. These three position variables were significantly related to the distance of the jump, through their relationships with the velocity of the approach and the vertical velocity of the CG at takeoff into the jump. Considered alone, they were not influential in determining the distance of the jump.

Production of chemotactic factor for lymphocyte by digestion of IgG with a highly purified polymorphonuclear leukocyte neutral thiol proteinase.

In the present study, we purified a neutral thiol proteinase from dog PMN leukocytes and indicated that the proteinase elaborated the chemotactic factor for lymphocytes by cleavage of IgG. The neutral thiol proteinase was purified about 744-fold by ion-exchange chromatographies and affinity chromatography, and the final preparation was over 70% pure. After incubation of dog IgG with the proteinase, three distinct protein peaks were seen by the gel filtration on Sephadex G-200. Only the third peak, perhaps a dialyzable peptide, showed a significant chemotactic activity for dog lymphocytes.

Separation and partial characterization of three forms of collagenase inhibitor from bovine gingiva.

Three forms of collagenase inhibitor were isolated; one bound to Con A-Sepharose and the other two did not. The Con A-bound (Mr 38,000) and the two unbound (Mr 50,000 and 22,000) inhibitors contained about 20, 15 and 65% of the total inhibitory activity, respectively. The bound and one of the unbound (Mr 22,000) inhibitors were fairly specific for mammalian collagenase; the other unbound inhibitor was rather non-specific and also inhibited trypsin and thermolysin, but not bacterial collagenase. All the inhibitors were heat stable (90 degrees C, 30 min) and unaffected by 4-aminophenylmercuric acetate, but were inactivated by reduction and alkylation.

Partial sequencing of two forms of concanavalin A-unbound collagenase inhibitor from bovine gingiva.

Three forms of collagenase inhibitor, one ConA-bound and two ConA-unbound, were extensively purified from bovine gingiva by sequential column chromatography. Analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed that inhibitory activity resides in proteins with M(r) of 26000-28000 and 22000 for ConA-bound and two ConA-unbound inhibitors, respectively. Of these, two ConA-unbound inhibitors were partially sequenced in the first 12 amino acids and found to have an identical sequence. The NH2-terminal sequence had 100% identity with TIMP-2 or MI.

Differential response of type I and type II cyclic AMP-dependent protein kinases in submandibular gland of isoproterenol-treated rats.

The cytosolic protein kinase isozymes were studied in relation to the secretion of saliva and the proliferative process induced by isoproterenol. At the same time as salivary secretion began, cytosolic protein kinase was activated and, in the absence of cyclic AMP, increased to a maximum level at 10 min after administration of the drug. The active state of the enzyme was maintained for 1-2 h. Chromatographic analysis of the cytosol enzyme revealed that in an activated state type II kinase easily dissociates into the catalytic and regulatory subunits while type I kinase hardly dissociates. Thus we conclude that type I kinase, at least in submandibular gland, is less dissociable in the presence of cyclic AMP than type II kinase but highly active in a ternary complex (R2-4 cAMP-C2). The presence of cyclic AMP-independent protein kinase, which co-chromatographed with protein kinase II, was demonstrated by use of a heat-stable inhibitor from bovine muscle, which totally inhibited the cyclic AMP-dependent enzymes, but stimulated the cyclic AMP-independent protein kinase. The level of protein kinase I decreased to its lowest value, about half that of the control value, at 10 h after isoproterenol injection and then increased slightly at 15 h, whereas type II kinase remained virtually unchanged, suggesting that the two protein kinase isozymes are independently regulated in the proliferating cells.

Rupture of a dissecting aneurysm into the superior vena cava in Marfan's syndrome.

Aneurysmal dilatation of the aorta with subsequent dissection or rupture occurs frequently in patients with Marfan's syndrome. These complications are among the major causes of death. We report the case of a 51-year-old man with annulo-aortic ectasia in Marfan's syndrome. Acute aortic dissection and rupture into the superior vena cava occurred 8 years after aortic valve replacement. The preoperative diagnosis was made by right heart catheterization and computed tomography. A markedly increased left-to-right shunt occurred with rapid enlargement of the fistula due to the fragility of the aortic wall characteristic of Marfan's syndrome. Postmortem examination demonstrated severe medial necrosis with rupture of the aortic wall into the superior vena cava which was adherent to the suture line of the aortotomy from the previous surgery. Type A aortic dissection with severe congestive heart failure strongly suggested rupture into the pulmonary circulation.

Surgical results for thoraco-abdominal aneurysm by modified DeBakey method using centrifugal biopump and renal cryopreservation.

BACKGROUND: In this paper, we report the surgical results of our DeBakey and Crawford combined method. METHODS: From 1985 to 1995, 22 consecutive patients with thoraco-abdominal aneurysms underwent a modified DeBakey and Crawford combined procedure to minimize the ischemic time for the spinal cord and visceral organs. The extent of aneurysm as classified by Crawford was as follows: Group I, 12; Group II, 4, Group III, 3; Group IV, 3. The etiology of the aneurysm was atherosclerosis in 19, cystic medial necrosis in 2, and aortitis in 1. The aneurysm was approached through the spiral opening method. First, end-to-side distal anastomosis was performed above the bifurcation under partial aortic clamping, and this was followed by proximal anastomosis. During the end-to-end proximal anastomosis, a Gott shunt tube or heparinless left heart bypass was used. In two patients, left renal artery had been previously reconstructed by a saphenous vein graft extending from the left common iliac artery. Then aneurysm was opened, and the right renal artery and superiors mesenteric artery were perfused with cold blood. In two patients, partial cardiopulmonary bypass and selective perfusion were performed. In eight patients, renal artery, celiac artery, superior mesenteric artery, and intercostal artery were reconstructed with a branch graft. RESULTS: No patient died within 30 days of surgery, however, one patient died of acute myocardial infarction (POD 54) and another of ventricular fibrillation during hemodialysis (POD 60). Postoperative complications included paraplegia, and renal failure requiring dialysis each in two patients. Postoperative angiography revealed 18/19 (94.7%) of grafts were patent. CONCLUSIONS: In conclusion, by using different techniques for spinal cord and visceral protection, including the Gott shunt, Biomedicus pump, renal cryopreservation, and separate revascularization of viscera and intercostal arteries, good results could be obtained.

The effect of direct lidocaine injection into the clamped aortic segment on the spinal evoked potential: early diagnosis for spinal cord ischemia.

PURPOSE: The aim of this study was to identify a method to determine whether segmental artery reconstruction was indicated during aortic clamping. METHOD: Spinal cord evoked potential (SCEP) and regional spinal blood flow were studied in 24 adult dogs. Using the left heart bypass technique, aortic clamping divided the aorta into thoracic, abdominal, and terminal segments. After the occlusion of the descending aorta and discontinuation of the perfusion to the abdominal segment, animals were assigned to four groups: no treatment with perfusion to the terminal aorta (group IA), no treatment with cessation of bypass (group IB), 5% lidocaine administration (5 mg/kg) into the abdominal segment with perfusion to the terminal aorta (group IIA), and lidocaine administration with cessation of bypass (group IIB). RESULTS: Cessation of bypass reduced spinal blood flow and SCEP amplitude. Lidocaine injection allowed for a significant rapid decrease in SCEP amplitude in group IIB compared with group IB (24.2% +/- 13.4% versus 92.3% +/- 33.2%; p = 0.0039). The degree of spinal blood supply was reflected immediately in the magnitude of SCEP amplitude change by the direct lidocaine injection. (group IB versus group IIB; p = 0.023). CONCLUSION: The direct injection of lidocaine into the clamped aorta results in a rapidly change in SCEP in the threat of ischemia and can be used to make an early detection of the segmental arteries perfusing to the spinal cord.

Coronary artery bypass grafting using the "Super Pulse" dynamic pulsatile cardiopulmonary bypass device in patients with cerebrovascular occlusive disease.

Patients with coronary disease complicated by severe carotid or intracranial arterial stenosis underwent coronary artery bypass graft surgery (CABG) using a novel method of dynamic pulsatile cardiopulmonary bypass (Super Pulse CPB). The Super Pulse technique can maintain the systolic pressure and systolic-diastolic amplitude in such a way that they mimic the physiologic circulation. Forty-five patients (33 males and 12 females, mean age 65.1 years) with coronary disease who had a greater than 75% stenosis of the carotid or intracranial arteries were evaluated. Evaluation was performed for the following 3 groups: 8 patients with conventional pulsatile CPB (Group I), 8 patients with conventional pulsatile CPB plus intraaortic balloon pumping (Group II), and 29 patients with Super Pulse CPB. Maximum, minimum, and mean perfusion pressures during CPB were 112.7, 53.6, and 76.9 mmHg (integrated mean), respectively, in Group III. The systolic-diastolic amplitude was significantly better than for Group I and similar to baseline pressures. No patients in Group II or Group III developed perioperative cerebral disorders or myocardial infarction, while in Group I perioperative cerebral disorders developed in 3 patients, myocardial infarction occurred in 2 patients, and 2 patients died during hospitalization. The initial performance of the Super Pulse CPB indicates excellent safety, and is useful for patients with co-morbid cerebral arterial disease.

[Radiofrequency modified maze operation for chronic atrial fibrillation with ASD; report of a case].

A 61-year-old man with congestive heart failure was referred to our hospital and diagnosed as atrial septal defect (ASD) [Qp/Qs = 1.6] with chronic atrial fibrillation. Occurrence of atrial fibrillation was supposed to be the cause of heart failure rather than L-R shunt of ASD. The patient was successfully operated on with the use of routine cardiopulmonary bypass. Radiofrequency modified maze procedure was done, and then small ASD (1 cm of diameter) was closed with patch. Postoperative transthoracic Doppler echocardiography confirmed clear A wave for transmitral and transtricuspid flow. The patient recovered uneventfully and was discharged in stable sinus rhythm and has been drug free since then.

[Rupture of the aneurysm of the sinus valsalva: thirteen years after the initial diagnosis].

We report a case of an unruptured aneurysm of the sinus Valsalva (URASV) which was followed thirteen years without surgery. A 47-year-old female had a heart murmur detected at age 34 during pregnancy. Though an URASV was diagnosed, because the aneurysm was less than 1 cm in size, no surgery was advised at that time. Thirteen years later, she gradually noticed of increased heart beats and also dyspnea on exertion. Echocardiogram showed an aneurysm of the sinus Valsalva ruptured to the RV cavity. In June 1994, resection of the aneurysm was performed. One year later, the patient was asymptomatic. This may be the second longest long-term follow-up report of the patient with an unruptured aneurysm of the sinus Valsalva.

[A case of mitral valvuloplasty with concomitant CABG in an aged patient].

A 79-year-old man was referred to our hospital complaining of the manifestation of mild heart failure. Echo cardiography and LV gram showed sever mitral regurgitation by the prolapse of posterior leaflet. CAG revealed coronary artery disease affected two vessels (LAD and RCA) without symptoms. Quadrangular resection of posterior leaflet (McGoon's method) without annuloplasty and concomitant single CABG to the LAD using a saphenous vein were performed. Postoperative course was satisfactory and the manifestation of heart failure was diminished. Mitral valvuloplasty with concomitant CABG may be a safe and effective procedure in the treatment of aged patients.