Effects of intraaortic balloon pumping on septal arterial blood flow velocity waveform during severe left main coronary artery stenosis

OBJECTIVES

We sought to evaluate the effect of intraaortic balloon pumping on the phasic blood velocity waveform into myocardium with severe coronary artery stenosis.

BACKGROUND

In the presence of severe coronary artery stenosis, it is not clear whether intraaortic balloon pumping augments intramyocardial inflow during diastole or changes systolic retrograde blood flow from the myocardium to the extramural coronary arteries.

METHODS

Using anesthetized open chest dogs (n=7), we introduced severe stenosis in the left main coronary artery to reduce the poststenotic pressure to approximately 60 mm Hg (>90% diameter stenosis). Septal arterial blood flow velocities were measured with a 20-MHz, 80-channel ultrasound pulsed Doppler velocimeter. Left anterior descending arterial flow, aortic pressure and poststenotic distal coronary pressure were measured simultaneously. The diastolic anterograde flow integral and systolic retrograde flow integral were compared in the presence and absence of intraaortic balloon pumping.

RESULTS

Although intraaortic balloon pumping augmented diastolic aortic pressure, this pressure increase was not effectively transmitted through stenosis. Septal arterial diastolic flow velocity was not augmented, and left anterior descending arterial flow was unchanged during intraaortic balloon pumping.

CONCLUSIONS

In the presence of severe coronary artery stenosis, intraaortic balloon pumping failed to increase diastolic inflow in the myocardium and did not enhance systolic retrograde flow from the myocardium to the extramural coronary artery. Thus, the major effect of intraaortic balloon pumping on the ischemic heart with severe coronary artery stenosis may be achieved by reducing oxygen demand by systolic unloading.

Long-term time course of regional changes in cholinergic indices following transient ischemia in the spontaneously hypertensive rat brain

Using an animal model of forebrain ischemia in spontaneously hypertensive rats (SHR) by 3-h bilateral carotid occlusion, and various indices of the cerebral cholinergic system were assessed for periods up to 24 weeks. The lesions observed histologically in the hippocampus of SHR 2 weeks after ischemia were less severe than those in the frontal cortex. Marked elevation of acetylcholine concentration was transiently observed in the frontal cortex, hippocampus and thalamus + midbrain at 2 weeks, and in the striatum at 1-4 weeks after ischemia. Choline acetyltransferase activity remained unchanged in all regions throughout the experimental period except for a minimal decrease in the frontal cortex at 4 weeks. Choline esterase (ChE) activity was slightly decreased in the frontal cortex at 2-4 weeks after ischemia but recovered by 8 weeks. A decrease in the hippocampus was seen at 8 weeks. The B(max) for the M1-receptor was significantly reduced by 2 weeks in the frontal cortex and by 4 weeks in the hippocampus. Low B(max) values in both regions persisted through week 24. These delayed hippocampal changes in the ChE activity and M1-receptor in SHR were similar to those of the very much delayed changes in M1-receptor previously reported in the gerbil model for transient ischemia. In contrast, Wistar-Kyoto rats (WKY), used as normotensive controls, exhibited no histological or biochemical changes for up to 24 weeks. The difference between SHR and WKY may depend on the more severe cerebral blood flow depletion during carotid ligation in the former. The chronic state of SHR after the transient ischemia may be a useful pathophysiological model for human cerebral infarctions with hypertension.

Basement membrane abnormality in merosin-negative congenital muscular dystrophy

In muscle biopsy specimens from three patients with merosin-negative congenital muscular dystrophy (CMD), there was marked variation in fiber size with evidence of necrotic and regenerating processes and with marked interstitial fibrosis. No muscle fibers or intramuscular nerves stained with merosin antibody. On electron microscopy, the basement membrane of all the muscle fibers was very poorly discernible and there were occasional disruptions, while the basement membrane of the Schwann cells was well preserved. On the other hand, the sarcolemmal basement membrane in merosin-positive CMD was well preserved even in patient with severe interstitial fibrosis. It remains to be determined how the defective basement membrane in merosin-negative CMD induces defective sarcolemma and eventual fiber necrosis.

Attenuated purine production during subsequent ischemia in preconditioned rabbit myocardium is unrelated to the mechanism of protection

Preconditioned hearts release less purines during ischemia than virgin hearts. This study tested whether this reduced purine production is related to the mechanism of protection by ischemic preconditioning. Coronary effluent from isolated rabbit hearts was collected and purine (adenosine + inosine + hypoxanthine) levels were measured. All hearts underwent two cycles of 5 min global ischemia, each followed by 10 min reperfusion. In the first minute of reflow after the first ischemic period untreated hearts released 155 +/- 14 nmol purines per g wet weight, but only 104 +/- 16 nmol/g following the second bout of ischemia (P < 0.05). Thus, preconditioned hearts released less purines during ischemia. When 8-(p-sulfophenyl)theophylline (100 microM), which prevents the infarct size-limiting effect of ischemic preconditioning by blocking adenosine receptors was present in the perfusate, the pattern of purine release was not altered (151 +/- 13 nmol/g during the first minute after the first 5-min ischemic episode dropping to 117 +/- 6 nmol/g after the second ischemic period P < 0.05). Furthermore, pharmacological preconditioning with 5 min exposure of the heart to either adenosine (10 microM) or phenylephrine (0.1 microM) 15 min prior to the first ischemia did not affect purine release during early reperfusion after either the first (144 +/- 16 nmol/g and 153 +/- 12 nmol/g, respectively) or second (84 +/- 12 nmol/g and 111 +/- 9 nmol/g, respectively) bout of ischemia. Since the attenuated purine release was apparently unaffected by the presence or absence of a protected state, we conclude that this pattern is unrelated to the mechanism by which preconditioning protects the heart.

Galactosamine alters glucose regulation in ten-day-old rats treated with a low dose of endotoxin

Hypoglycemia develops rapidly during septic shock and is a common and life-threatening problem in the human newborn. In adult animals, galactosamine alter glucose metabolism and increases mortality of endotoxic shock. Galactosamine may alter tissue glucose uptake and induce hypoglycemia in ten-day-old rats. The present study showed that galactosamine induced hypoglycemia and a high mortality without an increase in plasma insulin concentration in ten-day-old rats treated with a low dose of endotoxin. Galactosamine decreased tissue glucose uptake in endotoxin-treated animals. Hypoglycemia induced by galactosamine could be due to decreased gluconeogenesis.

Oxygen intake efficiency slope: a new index of cardiorespiratory functional reserve derived from the relationship between oxygen consumption and minute ventilation during incremental exercise

We investigated the usefulness of the oxygen intake efficiency slope (OIES) as a submaximal measure of cardiorespiratory functional reserve. OIES was derived from the relationship between oxygen consumption (VO2; ml/min) and minute ventilation (VE; l/min) during incremental exercise, which was determined by the following equation: VO2 = a logVE + b, where "a" represents OIES, which shows the effectiveness of ventilation. Maximal oxygen consumption (VO2max) is effort-dependent. There is no standard submaximal measurement of cardiorespiratory reserve that provides generally acceptable results. Exercise tests were performed by 17 normal volunteers on an ergometer using a symptom-limited Ramp protocol. Expired gas was continuously analyzed. OIES was calculated using the first 75%, 90%, and 100% of exercise data. We also determined the following submaximal parameters: the ventilatory anaerobic threshold (VAT), the slope of the minute ventilation-carbon dioxide production relationship (VE-VCO2 slope), and the extrapolated maximal oxygen consumption (EMOC). We analyzed the relationship between OIES, other submaximal parameters and VO2max, and examined the effects of submaximal exercise on OIES. The correlation coefficient of the logarithmic curve-fitting model was 0.991 +/- 0.006. OIES and VO2max were significantly correlated (r = 0.966, p < 0.0001). The correlation between OIES and VO2max was stronger than the correlation between VO2max and VAT, the VE-VCO2 slope and EMOC. OIES values for 100% and 90% of exercise were identical; OIES for 75% of exercise was slightly lower (3%). Our results suggested that OIES may provide an objective, effort-independent estimation of cardiorespiratory functional reserve.

Prolonged survival of rat hepatic allografts pretreated with a single donor-specific blood transfusion: the distribution of donor cells expressing class I major histocompatibility complex antigens in the recipient

We previously reported that a pretransplant transfusion of either ACI strain rat donor blood or PVG.r1 strain blood, which shares only the RT1.A class I major histocompatibility complex (MHC) region with an ACI donor, significantly prolonged the survival of ACI-to-LEW rat hepatic allografts, suggesting that the class I MHC antigens can be immunosuppressive in rat hepatic allografts. The distribution of the donor cells expressing RT1.Aa class I MHC antigens in the recipients was investigated using a MN4-91-6 mouse anti-rat class I (RT1.Aa) MHC monoclonal antibody. The donor class I MHC-positive cells accumulated mainly in the splenic white pulp and lymph nodes at 12 and 24 hr after blood transfusion, while very few cells were seen in the thymus, liver, lungs, and kidneys. The number of cells began to decrease in the splenic white pulp and lymph nodes at 24 hr after transfusion. This may indicate the destruction of donor cells by the recipient cells. Within 48 hr after transfusion, most cells disappeared from the recipient tissue. In an attempt to study the role of the spleen in inducing immunological unresponsiveness, a splenectomy was performed at the time of transplantation and this abrogated the prolongation of hepatic allograft survival in the recipients which received the donor blood. These findings suggest that the presence of class I MHC-positive cells in the splenic white pulp, a T-dependent area, may play an important role in inducing immunological unresponsiveness.

Evaluation of intramyocardial coronary blood flow waveform during intraaortic balloon pumping in the absence or presence of coronary stenosis

Our aim was to evaluate the effects of intraaortic balloon pumping (IABP) on the blood velocity waveform in the absence or presence of coronary artery stenosis. Using anesthetized open-chest dogs, the septal arterial blood flow velocities were measured with a 20 MHz 80-channel ultrasound pulsed Doppler velocimeter in the absence (n = 5) or presence (n = 3) of left main coronary artery stenosis. The blood velocity waveform was analyzed by calculating the systolic retrograde velocity integral (SR) and the diastolic antegrade velocity integral (DA). A slosh ratio was defined as SR/DA. The left anterior descending arterial flow (CBF), aortic pressure (AoP), and poststenotic distal coronary pressure (DiP) were also measured simultaneously. We compared the effect of IABP on the velocity waveforms in the absence and in the presence of coronary artery stenosis. In the absence of stenosis, IABP increased DiP during diastole and augmented DA while it also increased SR. IABP augmented the net CBF because of the greater increase in DA than SR. In the presence of stenosis, however, IABP did not increase DiP and resulted in no significant effect on the net CBF.

[Clinical characteristics and genetic background of secondary amyloidosis associated with rheumatoid arthritis in Japanese]

In order to examine the clinical characteristics and genetic background of secondary amyloidosis associated with rheumatoid arthritis, we analyzed clinical features and HLA typing of 85 patients in a multicenter study. Eighty-five patients with secondary amyloidosis associated RA were studied. The diagnosis of secondary amyloidosis were made on histological findings by biopsy or autopsy. The most common biopsy site was gastrointestinal tract (79.5%). Clinical symptom and the frequency at the time of diagnosis were; diarrhea (35 cases), abdominal pain (22 cases) and vomiting and nausea (16 cases). Abnormalities and the frequency in a laboratory test included proteinuria (49 cases), increased serum creatinine (32 cases), anemia (30 cases) and hematuria (15 cases). Twenty-eight patients were dead and 57 patients were alive at the time of the study. The average duration between diagnosis of amyloidosis and death was 19.4 +/- 18.5 (SD) months among the dead patients. The average duration after diagnosis of amyloidosis was 24.2 +/- 19.5 (SD) months in surviving patients. The causes of death were renal failure complicated with heart failure (6 patients), heart failure alone (3 patients) and renal failure alone (2 patients). Fifty-nine patients in the control group who were negative to amyloid deposition on biopsies at more than one site in the gastrointestinal tract, were clinically compared with patients in the amyloidosis group. No difference were noted in the age of RA occurrence and the stage between the two groups. As to the class, however, the number of patients with severe functional disorder (class 3 or severe) was larger in the amyloidosis group. There were no significant difference between the two groups in Lansbury's activity index. On hematology, biochemistry and urinalysis, the incidences of increased white blood cell count, anemia, increased platelet count, increased serum creatinine, hypoproteinemia, hypoalbuminemia, increased IgA, and increased urine and blood BMG were statistically significantly higher in the amyloidosis group than in the control group. HLA-A, -B, -C, and DR-locus antigens were compared in the 53 patients in the amyloidosis group and in the 59 subjects in the control group. There were no significant differences in frequency of HLA-A, and -B antigens between two groups. Frequency of CW7 antigen was significantly decreased in the amyloidosis group (13.2%) than in the control group (39.0%). Frequency of DR1 antigen was decreased in the amyloidosis group (3.8%) than in the control group (22.0%), although the difference was not significant. These findings suggest the possible involvement of genetic factors in the occurrence of amyloidosis. It is suggested that the occurrence of amyloidosis is suppressed by some genes which are linked with CW7 antigen.

Microheterogeneity of myocardial blood flow in rabbit hearts during normoxic and hypoxic states

The goal of this study was to evaluate microheterogeneity of myocardial blood flow and its dependence on arterial O2 tension (PaO2). We measured within-layer distribution of regional blood flows in the left ventricles of anesthetized rabbits in both normoxic and hypoxic states with myocardial region sizes in the range of 0.01-1.0 mm2. A novel method of digital radiography combined with the technique of 3H-labeled desmethylimipramine deposition enabled us to visualize and accurately quantitate regional blood flow at such high levels of resolution. To analyze myocardial blood flow patterns, we computed the coefficient of variation (CV) and the correlation between adjacent regional flows (CA). The CA values were larger in the hypoxic state (PaO2 = 26 +/- 5 mmHg) than in the normoxic state (PaO2 = 97 +/- 20 mmHg) at all levels of resolution (P < 0.001). In the normoxic state, there was a transmural difference in CA (P < 0.001); CA increased with depth of the left ventricle (from subepicardium to subendocardium). However, the relation between CA and the depth of the left ventricle was not statistically significant in the hypoxic state. The CV values were smaller in the hypoxic state than in the normoxic state at all levels of resolution (P < 0.001). When the degree of resolution was reduced from 0.01 to 1.0 mm2, CV decreased by 75% in the normoxic and by 69% in the hypoxic state. Thus we conclude that 1) the decrease in PaO2 increases similarity of blood flows in nearby regions and decreases myocardial blood flow heterogeneity, and 2) similarity of regional blood flows increases with depth of the left ventricle in the normoxic state, but this transmural difference disappears in the hypoxic state.

The F(ab')2 fragment of an anti-ICAM-1 monoclonal antibody attenuates liver injury after orthotopic liver transplantation

Long-term storage of liver grafts results in increased adhesion of leukocytes onto the sinusoidal walls. This eventually leads to posttransplant graft damage through disturbances of hepatic microcirculation. Intracellular adhesion molecule-1 (ICAM-1) is known to be involved in attachment of leukocytes. This study was designed to examine whether ICAM-1 participated in the pathogenesis of posttransplant liver injury. Inbred Lewis rats were used as both donors and recipients to avoid immunoreactivity. Donor livers were stored for either 1 or 6 hr in ice-cold Euro-Collins solution and subsequently implanted. Expression of ICAM-1 was examined immunohistochemically. In some rats that received livers stored for 6 hr, the intact IgG (1.0 mg/kg) or the F(ab')2 fragment (0.5 mg/kg) of an anti-ICAM-1 mAb (1A29) was administered via the tail vein immediately after reperfusion of portal blood. In the group receiving livers stored for 6 hr, ICAM-1 began to be expressed on the sinusoidal endothelial cells as early as 15 min after reperfusion of the portal blood. Strong ICAM-1 expression was observed from 2 hr up to 24 hr after reperfusion. In contrast, expression of ICAM-1 was not evident at any time point after surgery in the 1-hr storage group as well as in untransplanted, normal livers. Serum alanine aminotransferase (ALT) levels were significantly higher in the 6-hr storage group compared with those of the 1-hr storage group (1-hr: 171 +/- 9 IU/L; 6-hr: 825 +/- 109 IU/L, P < 0.05; mean +/- SEM) 24 hr after transplantation. Serum ALT levels were markedly reduced by treatment with the F(ab')2 fragment of 1A29 (247 +/- 34 IU/L, P < 0.05 vs. 6-hr storage group). This was associated with reduced accumulation of leukocytes in the liver. In marked contrast, treatment with the intact IgG of 1A29 increased serum ALT levels dramatically (5297 +/- 634 IU/L, P < 0.05 vs. 6-hr storage group) and reduced serum complement. Histological examination revealed focal hepatocellular necrosis 24 hr after surgery in the 6-hr storage group. Treatment with the F(ab')2 fragment decreased the liver damage; in marked contrast, treatment with the intact IgG strikingly aggravated the injury, as characterized by massive necrosis throughout the liver. Liver damage caused by the intact IgG might be related to activation of the complement system by the Fc portion of the antibody. Taken together, these results indicate that ICAM-1 is involved in the mechanism of postoperative liver injury following liver transplantation.

Suppression of hepatic allograft rejection in the rat by mitomycin C-treated donor splenocytes: in situ splenic distribution of donor class I major histocompatibility complex antigen-positive cells in the recipient

A single intravenous injection of 3 x 10(6) donor splenocytes treated with mitomycin C (MMC) 7 days before hepatic transplantation prolongs survival of hepatic allografts in the ACI(RT1a) to LEW(RT1(1)) rat combination. This effect is donor specific. The in situ distribution in the recipient of the donor cells administered preoperatively was investigated using intracellularly fluorescence-labeled donor splenocytes. The donor cells were accumulated mainly in the splenic white pulp and lymph nodes at 12 and 24 hr after injection. Contrarily, very few cells were seen in the thymus, liver, kidney, and lung. The number of cells with dull and weak fluorescence began to increase in the splenic white pulp and lymph nodes at 24 hr after injection. This may indicate the breakdown of donor cells by recipient cells. In contrast, a number of donor cells could be detected even after 48 hr and a few cells at 7 days after splenocyte injection in the LEW-to-LEW isogeneic combination. As we previously revealed the role of class I major histocompatibility complex (MHC) antigens in prolonging hepatic allograft survival in the rat, the splenic distribution of donor class I MHC-positive cells in the recipient after intravenous administration of MMC-treated donor splenocytes was studied using immunostaining with a MN4-91-6 mouse anti-rat RT1.Aa class I MHC monoclonal antibody. The donor class I-positive cells accumulated mainly in the splenic white pulp at 12 and 24 hr after injection. This is similar to that observed in the fluorescence study. Within 48 hr after injection, most cells had disappeared from the recipient tissue. These findings suggest that the splenic white pulp, a T-dependent area, may play an important role in inducing immunological unresponsiveness.

Cytokine production by SV40-transformed adherent synovial cells from rheumatoid arthritis patients

We examined the mRNA levels for various cytokines, including IL-1 alpha, IL-1 beta, TNF alpha, TGF-beta 1, GM-CSF, IL-6, IL-8, bFGF, PDGF-A, PDGF-B and IL-1ra, and IL-1 beta converting enzyme, and the protein levels of some of these cytokines in 19 SV40-transformed synovial cell clones. Among those tested, the mRNA levels for IL-6, bFGF and PDGF-A in rheumatoid arthritis (RA) cell clones were greater than those in non-RA cell clones. Moreover, except for one osteoarthritis (OA) cell clone, the mRNA levels for IL-8 in RA cell clones were also greater than those in non-RA cell clones. Although the protein levels were not always correlated with the mRNA levels, the exception being the same OA cell clone, the protein levels of cytokines, such as IL-1 alpha, IL-1 beta, IL-6 and IL-8, in RA cell clones were greater than those in non-RA cell clones. TNF-a was not detected in any cells tested at either the mRNA or the protein level. TNF-alpha upregulated the expression of GM-CSF mRNA in both RA cell clones and one OA cell clone, but not in the other OA cell clone or the normal cell clone. Taken together, these SV-40 transformed synovial cell clones retained many of the original characteristics in terms of cytokine production.

Effect of ligand orientation on hepatocyte attachment onto the poly(N-p-vinylbenzyl-o-beta-D-galactopyranosyl-D-gluconamide) as a model ligand of asialoglycoprotein

The orientation effect of galactose ligand on hepatocyte attachment was investigated. Poly(N-p-vinylbenzyl-o-beta-D-galactopyranosyl-D-gluconamide )(PVLA), a beta-galactose-carrying styrene homopolymer, was used as a model ligand for the asialoglycoprotein receptors on hepatocytes. PVLA was transferred onto the poly(gamma-benzyl L-glutamate) (PBLG) or PBLG/poly(ethylene glycol) (PEG)PBLG Langmuir-Blodgett (LB) films as the monolayer level. The dichroic fluorescence values of the confocal microscope indicated that the PVLA transferred onto the LB films was located with a preferential orientation of its molecular axes with regard to the direction of the alpha-helix of polypeptide. Hepatocyte recognized well-oriented galactose moieties of the surface of PVLA through asialoglycoprotein receptors.

Assignment of the E4TF1-60 gene to human chromosome 21q21.2-q21.3

The gene encoding human transcription factor E4TF1-60 was previously mapped to chromosome 21q21. We analyzed the localization of the E4TF1-60 gene in more detail by genomic Southern hybridization and determined the sequence of the exons and the regions surrounding the intron boundaries. We report here that E4TF1-60 locates in the long arm of chromosome 21 at q21.2-q21.3 and contains a total of ten exons.

Structural effect of galactose residue in synthetic glycoconjugates on interaction with rat hepatocytes

N-p-Vinylbenzyl-O-beta-D-galactopyranosyl-(1,4)-D-gluconamide++ + (PVLA) has been used as an asialoglycoprotein model polymer. Rat hepatocytes expressing asialoglycoprotein receptors are capable of binding to hydrophobic plastic dishes coated with PVLA. PVLA, water-soluble polystyrene derivatives bearing galactose residues preferentially adsorb to plastic plates made of polystyrene rather than those of poly(methyl methacrylate). Hence, we modified chitosan beads with linear chains composed of a long alkyl or phenyl moiety to study the effect of structural variations of adsorbed PVLA, and investigated the extent of hepatocyte attachment to the hydrophobic beads coated with PVLA. The attachment was independent of the amount of immobilized PVLA; rather, it was dependent on the hydrophobicity of the beads with PVLA. To simplify the surface of the hydrophobic beads with PVLA, galactopyranoses were covalently linked to chitosan beads via hydrophobic spacer arms, and hepatocyte attachment was compared among the prepared beads. The beads with spacer arms containing phenylalanine and a phthalic moiety showed increased hepatocyte attachment, which was elicited by galactose residues on the beads. These results suggest that rotational restriction or stiffness and hydrophobicity due to the phenyl moiety are essential to enhance the specificity of terminal galactose in PVLA. This analysis contributes to the design and optimization of an artificial ligand for cellular receptors recognizing sugar moieties.

KatG sequence deletion is not the major cause of isoniazid resistance in Japanese and Yemeni Mycobacterium tuberculosis isolates

One of the mechanisms of isoniazid resistance to Mycobacterium tuberculosis has been proved to be the chromosomal deletion of katG. Based on this finding, 22 isoniazid-resistant isolates of M. tuberculosis obtained in Japan and Yemen were analysed for katG by polymerase chain reaction and catalase activity. Only six (27%) of the 22 isolates were compatible with the mechanism (lack of amplification of katG and loss of catalase activity). In contrast, eight isolates (36%) were katG positive but catalase activity-negative and eight (36%) were positive for both factors, indicating that isoniazid resistance is multifactorial and the deletion of katG was not the major cause of resistance in the isolates examined in this study.

Altered gene expression of natriuretic peptide receptor subtypes in the kidney of stroke-prone spontaneously hypertensive rats

1. To elucidate the physiological and pathophysiological role of the natriuretic peptide system in the progression of hypertensive renal disease, we examined the gene expression of natriuretic peptide receptor subtypes, guanylate cyclase-A (GC-A), guanylate cyclase-B (GC-B) and clearance receptor (C receptor), in the kidney of stroke-prone spontaneously hypertensive rats (SHRSP) at 8 and 20 weeks of age, and compared them with their gene expression in age-matched Wistar-Kyoto (WKY) rats. 2. Northern blot analyses revealed that messages for three natriuretic peptide receptor subtypes were expressed in the kidney, and their expressions were higher in the glomeruli than in the whole kidney in each strain. 3. In 20 week old rats with established hypertension, the glomerular concentration of GC-A mRNA was significantly higher in SHRSP than in WKY. The concentrations of GC-B and C receptor mRNA in the glomeruli tended to increase and decrease, respectively, but they were not statistically significant in SHRSP. 4. In 8 week old rats, the glomerular concentrations of GC-A, GC-B and C receptor mRNA were not significantly different between SHRSP and WKY. 5. This study demonstrates that in the progression of hypertension, the expression of GC-A, which mediates biological actions of natriuretic peptides, is enhanced in the kidney of SHRSP compared to that of WKY. Together with the augmented secretion of the ligands previously revealed, altered expression of natriuretic peptide receptor subtypes in SHRSP may have a deterrent role in the development of hypertension and its renal complications.

Preparation of a monoclonal antibody against mouse brain natriuretic peptide (BNP) and tissue distribution of BNP in mice

1. In order to explore the significance of brain natriuretic peptide (BNP), a cardiac hormone secreted from the ventricle, in mice, we prepared a monoclonal antibody against mouse BNP (mBNP) and established a specific radioimmunoassay (RIA) for mBNP. 2. A monoclonal antibody, KY-mBNP-I, was prepared by the fusion of mouse myeloma cells X63-Ag8.653 with spleen cells of the BALB/c mouse immunized with synthetic mBNP[108-121] conjugated to bovine thyroglobulin. KY-mBNP-I belonged to an IgG2a subclass and showed a high affinity for mBNP (Ka = 1.8 x 10(11) mol/L-1). 3. The RIA established that using KY-mBNP-I was highly sensitive and specific for mBNP, with an IC50 value of 3 fmol/tube and cross-reactivities of less than 0.003% with related natriuretic peptides. mBNP-like immunoreactivity (mBNP-LI) was detected in the mouse atrium (0.35 +/- 0.02 nmol/g), ventricle (20.5 +/- 0.5 pmol/g) and kidney (0.50 +/- 0.05 pmol/g), but not in other tissues including brain. 4. Gel filtration analysis revealed that the major component of tissue mBNP-LI was co-eluted with synthetic mBNP[77-121], a 45-amino acid mature peptide. 5. The monoclonal antibody and RIA for mBNP established here will provide useful tools to investigate the functional significance of BNP in mice, coupled with the genetic engineering approach.

[A case of Sjögren's syndrome and systemic lupus erythematosus complicated with necrotizing angiitis of the gallbladder]

A 71 year-old man with Sjogren's syndrome and systemic lupus erythematosus was admitted to our hospital because of abdominal pain and fever. Laboratory investigation showed an ESR of 76 mm/hr, elevation of CRP and marked leukocytosis. Abdominal ultrasound and CT scan showed enlargement of the gallbladder and intravesicular sludge without stones. With a clinical diagnosis of acute cholecystitis and pan-peritonitis, the surgical procedures including cholecystectomy were performed. Histological examination of the gallbladder showed a presence of necrotizing angiitis of small arteries. The postoperative course was uneventful with daily administration of 10 mg of prednisolone.

New chronic pancreatitis model with diabetes induced by cerulein plus stress in rats

To establish a new experimental model of chronic pancreatitis (CP) with diabetes, we investigated pancreatic endocrine function, blood flow, and histopathology in CP induced by repetition of cerulein injection plus water immersion stress in rats. CP rats were treated with water immersion stress for 5 hr and two intraperitoneal injections of 20 micrograms/kg body weight of cerulein once a week for 16 weeks. In the CP group, pancreatic contents of protein, amylase, elastase, and lipase significantly decreased to 64, 38, 23, and 68% of the control group, respectively. In oral glucose tolerance test (glucose 2 g/kg body wt), blood glucose level in the CP group was 212.1 +/- 97.8 mg/dl (mean +/- SD) at 30 min and was significantly higher than the control group (126.3 +/- 15.4 mg/dl)(P < 0.05). Two of seven rats in the CP group showed an obvious diabetic insulin in the CP group was 640.1 +/- 148.7 pM, significantly lower than in the control group (1133.4 +/- 242.0 pM)(P < 0.001). However, insulin content in the pancreas was 12.37 nmol/pancreas). In CP rats, winding and dilatation of surface blood vessels and gland atrophy were evident. Marked fibrosis, fatty changes, and destruction of lobular architecture were also demonstrated microscopically, although the structure of each pancreatic islet was preserved and each islet was fully stained with anti-insulin antibody. In the CP group, pancreatic blood flow by the hydrogen gas-clearance method was 197.6 +/- 33.0 ml/min/100 g, which was significantly less than the control group (276.2 +/- 19.1 ml/min/100 g) (P < 0.001). Thus, we conclude that the CP model induced by cerulein plus stress is a new CP model with diabetes in rats, in which the glucose tolerance was impaired without loss of insulin reserve.

Crystal structure of a mixed chain diacylglycerol, 1-stearoyl-3-oleyl-glycerol

Diacylglycerols composed of one saturated and one unsaturated chain make up the hydrophobic core of many biological membranes. We report here the first crystalline structure of such a mixed chain diacylglycerol. The mixed chain diacylglycerol, 1-stearoyl-3-oleyl-glycerol (1,3-SODG) was produced by solution isomerization of 1-stearoyl-2-oleyl-sn-glycerol. 1,3-SODG was isolated by flash chromatography and crystallized by slow evaporation in ethyl acetate at 4 degrees C. The melting point was 42.5 degrees C and the enthalpy was 18.0 kcal/mol. The crystal structure was determined to a final R factor of 0.127. Four molecules are present in the monoclinic unit cell: space group Cc, a = 9.362(2), b = 5.495(2), c = 77.92(3)A, beta = 91.46(2), V = 4007(4)A3, Z = 4, D = 1.032 g/cm3. The molecule forms an extended V-shaped conformation with the oleate and stearate chains coming off the two ends of the glycerol with an angle between their planes of 94 degrees. The two chains pack separately in individual layers and do not interact. The hydrogen bonds between the free hydroxyl group on the glycerol-2 position and the carbonyl oxygen on the oleyl chain of an adjacent molecule are 2.78 A in length and stabilize the glycerol layers. The stearoyl chain is roughly straight and packed in a triclinic parallel subcell. Both portions of the oleyl chain also pack in triclinic parallel packing. The torsion angle sequence along the double bond extending from the oleyl carbons C7 to C13 is tscsst (173 degrees, -152 degrees, -17 degrees, -157 degrees, -163 degrees, -178 degrees). This sequence is different from other monounsaturates. The torsion angle sequence around the glycerol region shows that the glycerol conformation is quite similar to the A conformer of racemic alpha monolaurin, and to 1,3-di-11-bromoundecanoyl glycerol, but completely unlike 1,2-diacyl-sn-glycerols. Thus the glycerol conformation appears to be driven by the hydrogen bond formation, which in turn determines whether chains interact or are segregated. In 1,3-diacylglycerols the two acyl chains point in different directions and are segregated. In 1,2-diacylglycerols the acyl chains lie side by side and must interact. When the two chains are quite different, then serious problems in packing occur, giving rise to disordered crystal packing. Probably as a result of the disordered chain packing in 1-stearoyl-2-oleyl-sn-glycerol (Di, L. and D.M. Small. 1993. J. Lipid Res. 34: 1611-1623) we were not successful in growing adequate crystals suitable for crystallographic structure determination of this 1,2 mixed chain diacylglycerol.

Protective effect of nitric oxide on development of acute pancreatitis in rats

Nitric oxide (NO) has been implicated to regulate pancreatic circulation, promote capillary integrity, and inhibit leukocyte adhesion. We investigated the role of NO in the development of pancreatitis. Nitro-L-arginine, an inhibitor of NO synthase, in total dose of 35 mg/kg body wt was infused in the rats with edematous pancreatitis induced by two intraperitoneal injections of cerulein (20 micrograms/kg). L-Arginine (125 or 250 mg/kg), a NO donor was intravenously administered twice in the rats with hemorrhagic pancreatitis induced by water-immersion stress plus two intraperitoneal injections of cerulein (40 micrograms/kg). The degree of pancreas edema, serum amylase levels, and histologic alterations were investigated. Nitro-L-arginine exacerbated cerulein-induced pancreatitis and caused a decrease in pancreatic blood flow. L-Arginine ameliorated the severity of hemorrhagic pancreatitis dose dependently and improved the pancreatic blood flow. These findings suggest that NO could confer protection against the development of hemorrhagic pancreatitis, probably through improvement of the pancreatic microcirculation.