Heart rate and force-frequency effects on diastolic function of the left ventricle in exercising dogs

BACKGROUND

Previous studies from our laboratory have shown pronounced augmentation of the force-frequency relation on myocardial contraction during exercise, but the influence of this effect on diastole has not been investigated.

METHODS AND RESULTS

Accordingly, the effect of changing heart rate on left ventricular (LV) relaxation, filling dynamics, and pressure-volume relations during exercise was studied in eight conscious dogs. The exercise heart rate was slowed from 208 +/- 21 (SD) to 163 +/- 11 beats per minute by injection of a specific sinus node inhibitor (UL-FS 49, or zatebradine, 0.6 mg/kg) during continuous exercise. Heart rate was then abruptly restored to the predrug level by atrial pacing during continued exercise. LV volume was calculated by use of implanted ultrasonic crystals, and LV pressure was determine with an implanted micromanometer. Comparing conditions after pacing back to a heart rate of 210 beats per minute with those obtained when the heart rate was slowed by atrial pacing, LV dP/dtmax was increased by 27% at the higher rate (P < .01), despite a marked decrease in LV end-diastolic pressure (24 +/- 4 versus 10 +/- 5 mm Hg, P < .01) and the time constant of isovolumic LV pressure decay (tau) was significantly shortened (19 +/- 5 versus 14 +/- 4 milliseconds, P < .01). The peak rapid filling rate in early diastole (PFR) was not significantly changed by increasing the heart rate, since it was maintained at the slower rate. During exercise, at the slowed heart rate the early portion of the diastolic pressure-volume curve was significantly shifted upward and to the right compared with that at the physiological heart rate, but the late portion of the curve was unchanged.

CONCLUSIONS

These data indicate that the negative inotropic effect of the force-frequency relation when heart rate was slowed during exercise caused pronounced impairment of LV relaxation and early filling dynamics. Conversely, an important component of the pronounced improvement of diastolic ventricular function during normal exercise was shown to result from exercise-induced enhancement of the positive inotropic effects of the force-frequency relation on myocardial contraction and relaxation.

Hyposecretion of atrial natriuretic peptide due to associated right atrial infarction in a patient with acute right ventricular infarction?

A patient with acute right ventricular infarction who showed hyposecretion of atrial natriuretic peptide (ANP) in spite of abnormally high right atrial pressure and who died of a severe low cardiac output syndrome is reported. Right atrial infarction, which was proven at autopsy, may be responsible for this endocrine failure.

Sperm-egg fusion in the sea urchin is blocked in Mg(2+)-free seawater

Magnesium ions as well as calcium ions are required for successful fertilisation in sea urchins. In the absence of Mg2+ spermatozoa attached to the egg plasma membrane, their acrosomal processes passing through the vitelline envelope, but could not enter the egg cytoplasm (Sano et al., Dev. Growth Differ. 22, 531-41, 1980). Such an individual spermatozoon was observed microscopically to resume entry into the egg immediately after the addition of a sufficient amount of Mg2+ to the surrounding medium. Neither any change in membrane potential nor an increase in intracellular Ca2+ concentration of the egg was observed after insemination in the absence of Mg2+, although both could be observed after the addition of Mg2+. The sperm heads did not show fluorescence when attached to the surface of an egg previously microinjected with mithramycin A in Mg-free seawater, indicating that there was no connection between the sperm and the egg. Therefore, occurrence of fertilisation potential must be a post-fusional event. These results suggest that Mg2+ are indispensable for fusion between the sperm acrosomal membrane and the egg plasma membrane.

Effects of 1 alpha-hydroxyvitamin D3 on lumbar bone mineral density and vertebral fractures in patients with postmenopausal osteoporosis

The effects of 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3] on bone mineral density, fracture incidence, and bone metabolism were evaluated by a double-blind, placebo-controlled study. Eighty postmenopausal osteoporotic Japanese women (71.9 +/- 7.3 years, mean +/- SD) were randomly assigned to 1 microgram of 1 alpha(OH)D3 daily or inactive placebo for 1 year. All patients were given supplemental calcium (300 mg of elemental calcium daily). Lumbar (L2-L4) bone mineral density (BMD) determined by dual energy X-ray absorptiometry increased 0.65% with 1 alpha(OH)D3 treatment and decreased 1.14% with placebo (P = 0.037). BMD in both the femoral neck and Ward's triangle did not yield any significant differences between the two groups, whereas trochanter BMD in the 1 alpha(OH)D3-treated group increased 4.20% and decreased 2.37% with placebo (P = 0.055). X-ray analysis demonstrated that new vertebral fractures occurred in two patients with 1 alpha(OH)D3 and in seven patients with placebo. The vertebral fracture rate in the treated group was significantly less (75/1000 patient years) than in the control group (277/1000 patient years; P = 0.029). Hypercalcemia (12.1 mg/100 ml) occurred in one patient receiving 1 alpha(OH)D3; however, the serum calcium level in this patient promptly decreased to the reference range after cessation of the treatment. There were no significant changes in serum creatinine level in either group. A significant increase in urinary excretion of calcium was found but there was no significant change in urinary excretion of hydroxyproline in the treated group. The serum level of bone-derived alkaline phosphatase activity significantly decreased by -26 +/- 26 (mU/ml) after the treatment (P = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Glomerular nodular lesions in non-amyloid immunoglobulin deposition disease: their pathogenetic relationship to mesangiolysis

Renal biopsy of a 70-year-old woman with clinical features of rapidly progressive glomerulonephritis revealed nodular glomerulosclerosis with conspicuous crescent formation. Other peculiar findings were the presence of many mesangiolytic cystic lesions and multinucleated giant cells in the cystic lesions. By immunofluorescent microscopic study, lambda light and gamma heavy chains were found in mesangial nodules, Bowman's capsule and the tubular basement membrane. Multiple myeloma was diagnosed by bone marrow examination. Autopsy performed two months later revealed systemic deposition of lambda light and gamma heavy chains, and fairly advanced nodular glomerulosclerosis. Most of the glomerular nodular lesions had a lamellar structure. Amyloid was not found. The high incidence of both mesangiolytic lesions in the biopsy specimen and laminated glomerular nodules in the autopsy material supports the previously proposed pathogenetic relationship of these two findings.

[The etiology and clinical features of hemolytic uremic syndrome]

The incidence of hemolytic uremic syndrome (HUS) has been increased for these several years. As the cause of HUS, verotoxin-producing E coli (VTEC) is very important. By our nationwide survey for five years from 1986 to 1990, 146 cases with HUS were compiled. Among 122 cases of HUS, 101 cases (82.8%) had good prognosis, 15 cases (12.3%) had renal or CNS residue. And death rate was 4.9% (6 cases). Clinical features were compared between the groups of good and poor prognosis. In the group of poor prognosis, impaired consciousness, convulsion and hypertension were significantly high. The data of biochemistry such as BUN, creatinine, GOT, GPT, C3, CH50 and CRP were significant between two groups. Demonstration of VTEC and positive serum antibody were seen in 60% among 35 cases. Dr Takeda of National Children's Hospital estimates that the incidence of hemolytic colitis is 1200 cases per year, and the occurrence of HUS is about 100 cases per year, among them 70% cases may be caused by VTEC.

Pharmacological profile of the novel putative anxiolytic agent 1-amino-5-bromouracil

The newly synthesized compound, 1-amino-5-bromouracil (ABU, CAS 127984-93-4), showed unique anxiolytic activity in rats and mice. Its minimum effective dose was 10 mg/kg p.o. in the Geller type conflict test in rats, and it showed anxiolytic activity at a dose of 20 mg/kg i.p. in the Vogel type conflict test in mice. ABU also induced loss of the righting reflex in mice. The ED50, a dose level that induces loss of the righting reflex in 50% of mice, was 86.4 mg/kg p.o. On the other hand, ABU showed only weak activities both potentiating the drug-induced anesthesia and myorelaxing in comparison with diazepam. Furthermore ABU did not show an affinity for benzodiazepine receptor. Thus, the pharmacological profile of ABU is concluded to be different from that of diazepam.

Assessment of left ventricular filling dynamics utilizing Doppler echocardiography in acute coronary syndrome

To evaluate prolonged diastolic dysfunction in acute coronary syndrome, mitral inflow velocities and left ventricular wall motion were examined with pulsed-wave Doppler and two-dimensional echocardiography in 14 patients with successful reperfusion, 8 patients without reperfusion after acute myocardial infarction, and in 10 patients with prolonged angina. Early peak flow velocity and the ratio of early to atrial peak flow velocity increased gradually both after the onset of acute myocardial infarction with reperfusion and cessation of angina pectoris. However, in acute myocardial infarction without reperfusion, early peak flow velocity and the ratio of early to atrial peak flow velocity decreased significantly. Atrial peak flow velocity remained unchanged in acute myocardial infarction with reperfusion, while it was decreased in angina pectoris on the seventh day. Regional systolic dysfunction abated gradually in acute myocardial infarction with successful reperfusion, and regional systolic dysfunction was not detected in angina pectoris on the third day. Thus, abnormalities in left ventricular early diastolic filling persisted for several days after reperfusion in acute myocardial infarction or cessation of angina. Left ventricular late filling remained unchanged in acute myocardial infarction, whereas, in angina pectoris, a compensatory increase in late filling diminished gradually with an increase in early filling. These results indicate that there are different types of recovery process after diastolic filling abnormalities in patients with acute coronary syndrome.

[Successful treatment of acute myelogenous leukemia in an elderly patient with cytarabine ocfosfate]

A 77-year-old female with left hemiplegia caused by cerebral infarction and with mild senile dementia was admitted for further examination of hematological abnormalities. She was diagnosed as acute myelogenous leukemia (AML-M5a) according to French-American-British classification. Since intensive combination chemotherapy seemed difficult, she was treated with oral administration of cytarabine ocfosfate (200 mg/day, for 14 days), a cytidine deaminase-resistant derivative of Ara-C, resulting in complete remission. Major side effects were nausea, vomiting and appetite loss, but their incidences were reduced tolerably when cytarabine ocfosfate was given just before sleeping. Cytarabine ocfosfate might be useful to treat AML in elderly patients having certain complications such as cerebrovascular disease.

Coronary reperfusion enhances recovery of atrial natriuretic peptide secretion. Salvaging endocrine function in patients with acute right ventricular infarction

BACKGROUND

The heart has been demonstrated not only to be a pumping organ but also an endocrine organ secreting atrial natriuretic peptide (ANP). We hypothesized that myocardial ischemia may affect ANP secretion and that reperfusion therapy for acute myocardial infarction can preserve endocrine function of the heart.

METHODS AND RESULTS

Twenty patients with acute right ventricular infarction were examined who underwent reperfusion therapy on admission. These patients had proximal occlusion of the dominant right coronary artery involving the right atrial branches: 9 patients with successful reperfusion (SRP group) and the remaining 11 patients with unsuccessful reperfusion (URP group). Within 24 hours after the onset of infarction, a volume loading test was performed after reperfusion therapy with measurements for plasma ANP levels and hemodynamics. Before the volume loading test, the plasma ANP level and mean right atrial pressure were similar between these two groups. However, in the URP group, percent increase in ANP in response to volume loading was strikingly smaller (URP, 45 +/- 18% versus SRP, 133 +/- 25%; P < .01) despite similar percent increase in mean right atrial pressure (URP, 100 +/- 46% versus SRP, 86 +/- 23%). The peak ANP level occurred significantly later in the URP group (69 +/- 16 hours) than in the SRP group (28 +/- 9 hours, P < .001) after the onset of infarction.

CONCLUSIONS

The response of ANP release to volume loading is attenuated in patients with right ventricular infarction without coronary reperfusion. However, successful reperfusion induces a rapid recovery of cardiac endocrine function as well as its mechanical function. A sufficiently elevated plasma ANP level may be a useful predictor of hemodynamic improvement in patients with right ventricular infarction.

Erythromycin does not directly affect neutrophil functions

To determine whether erythromycin could affect neutrophil functions, we measured N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced chemotaxis and superoxide generation of neutrophils in the presence of erythromycin at various concentrations. Erythromycin had no effect on either of them. We further confirmed that intracellular free calcium concentration ([Ca2+]i) was not influenced by FMLP stimulation in the presence of erythromycin. Our results indicate that erythromycin has no direct effects on neutrophil functions in vitro, although it is reported that erythromycin inhibits the local migration of neutrophils in the small airways of subjects with asthma.

In vitro and in vivo changes of serotype in Pseudomonas aeruginosa isolates by anti-pseudomonal drugs

The present study was designed to clarify whether anti-pseudomonal drugs affected in vitro and in vivo changes in serotypes of Pseudomonas aeruginosa isolates. Forty-two isolates of P. aeruginosa belonging to different serotype groups were each incubated in Mueller-Hinton broth including piperacillin, cefsulodin, ceftazidime, imipenem, gentamicin or norfloxacin at 1 approximately 4 MICs at 35 degrees C for 20 hours. The bacterial cells in the media were serotyped after the incubation. In each experiment with these six drugs, serotypes of 4 (9.5%) to 8 (19.0%) of the 42 isolates changed to other different groups. There was no relationship between the serotypes of the variants formed with the anti-pseudomonal drugs and kinds of the drugs. In the case of P. aeruginosa TA-2 isolate, the different concentrations (1/2 MIC and 2 x MIC) of cefsulodin induced the distinct changes in serotypes such as the poly-agglutinable (M, G) and non-typable groups, respectively. The time course for the formation of the variant cells was investigated during the incubation of P. aeruginosa TA-2 isolate in the presence of cefsulodin, respectively. In this case, the variant cells appeared 6 hours after incubation and continued to grow together with the intact cells. On the other hand, the variant cells with anti-pseudomonal drugs (cefsulodin, imipenem and gentamicin) were also formed in the model infections in mice. The present results indicated that the co-existence of colonies with different serotypes in some isolates of P. aeruginosa was partially due to the alternation of serotypes with anti-pseudomonal drugs given to patients with infection.

[Bacteremia of in-patients of the department of urology]

Thirty cases of bacteremia out of 1512 patients who had been admitted to our Department between February 1988 and June 1991 were reviewed. They consisted of 22 males and 8 females and their age ranged from 32 to 88 years (mean 62.7). 25 of the patients (83.3%) had malignant diseases of which bladder cancer (15 cases) was predominant and 5 had benign diseases. Gram positive bacteria were isolated in 18 cases (56.2%) and fungi in 4 cases (12.5%) from blood culture. Of these MRSA was most prevalent: 6 cases (18.8%), followed by S. epidermidis: 4 cases (12.5%), P. aeruginosa: 3 cases: E. faecalis: 3 cases and Corynebacterium: 3 cases (9.4%). Analysing the onset of bacteremia for each case, in three cases urinary tract infections, in one case a surgical wound infection and in one case a skin infection were prominent before the diagnosis of bacteremia. From their background, 23 cases (76.7%) were so-called compromised hosts. A total of 7 cases had died, 6 cases of bladder cancer and one case of testicular cancer, five of them were on systemic anti-cancer chemotherapy. Of those cases who expired, P. aeruginosa was isolated in two cases, Candida in two cases, MRSA in one case and E. faecium in one case, Corynebacterium in one case. It was noteworthy that in two cases where blood cultures were positive for P. aeruginosa and one case where the blood culture proved positive for Candida, drastic decrease of the peripheral leukocyte number during anti-cancer chemotherapy was seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Specific induction of LTC4 synthase by retinoic acid in rat basophilic leukemia-1 cells

Overnight (10-16 h) incubation of retinoic acid (RA), a derivative of vitamin A, specifically induced LTC4 synthase activity (5 to 10-fold), but not LTA4 hydrolase activity in the lysate of rat basophilic leukemia-1 (RBL-1) cells. A time course study revealed that the increase of LTC4 synthase activity was time dependent and that the peak value was obtained after a 24-hour incubation with RA. The induction of enzyme activity was specifically localized to the microsomal fraction. Glutathione (GSH) S-transferase activity measured by using the same cell lysate as an enzyme source and 1-chloro-2,4-dinitrobenzene (DNCB) as a substrate was not influenced by RA treatment, indicating that the induction by RA is specific for membrane-bound LTC4 synthase. The induction of LTC4 synthase may be an important regulatory mechanism of peptide-LT synthesis in allergy and inflammatory diseases.

Treatment of severe pertussis by administration of specific gamma globulin with high titers anti-toxin antibody

Our patient presented with severe respiratory distress and marked pleocytosis. She was mechanically ventilated and received gamma globulin with high titers of anti-pertussis toxin and anti-filamentous hemagglutinin. Her clinical signs improved and a notable decrease in white blood cell count was observed. Ten months after treatment, the patient showed normal physical and mental development and anti-pertussis toxin and anti-filamentous hemagglutinin titers were significantly increased. Recently, the effectiveness of gamma globulin therapy has been emphasized again. Our experience supports the use of iv gamma globulin infusion. Also, gamma globulin did not influence the patient's own immunologic response to pertussis. Gamma globulin therapy with high anti-pertussis toxin titers could be considered for treatment of severe pertussis.

Increase in plasma concentration of ubiquitin in dialysis patients: possible involvement in beta 2-microglobulin amyloidosis

beta 2-Microglobulin(beta 2-M) amyloidosis is a serious complication of dialysis therapy; however, its pathogenesis is still unclear. Recent studies have indicated that ubiquitin has amyloid enhancing factor activity, raising the possibility that ubiquitin plays a role in beta 2-M amyloidogenesis. In this study, synovial tissue from patients with long-term dialysis was examined immunohistochemically. The synovial tissue was labeled with anti-ubiquitin antibody, indicating co-deposition of ubiquitin with beta 2-M amyloid. To elucidate the involvement of plasma ubiquitin, we established a specific radioimmunoassay for ubiquitin. Using this method, we observed that the plasma concentration of ubiquitin-like immunoreactivity in dialysis patients was significantly higher than that in normal subjects. In chronic renal failure patients, the plasma concentration of ubiquitin-like immunoreactivity was also significantly higher than that in normal controls, which finding suggests that a reduction in renal clearance is, at least in part, responsible for the increased plasma concentration of ubiquitin. In dialysis patients, plasma concentrations of ubiquitin-like immunoreactivity in patients with carpal tunnel syndrome, one of the major symptoms of beta 2-M amyloidosis, were significantly higher than those in patients not exhibiting this syndrome. These results suggest a possible involvement of plasma ubiquitin in beta 2-M amyloidosis.

Ca2+ response in single human T cells induced by stimulation of CD4 or CD8 and interference with CD3 stimulation

A Ca2+ imaging method has been used to demonstrate simultaneously the magnitude and time course of the increase in the intracellular Ca2+ concentration ([Ca2+]i) in 10-30 individual human peripheral T cells following stimulation by anti-CD4 or anti-CD8 monoclonal antibody (MAb) as well as anti-CD3 MAb. The rise in [Ca2+]i began within 10 s of the introduction of the MAb and reached a peak of 240 nM (mean of 73 cells) in 20-40 s. The peak was followed by a slow decrease persisting for 6-8 min. Comparing Ca2+ responses in the presence and absence of external Ca2+, the rise in [Ca2+]i was found to be caused by both transient intracellular Ca2+ release and a long-lasting Ca2+ influx from outside the cell. Cross-linking of CD4 or CD8 using anti-IgG antibody augmented the response in individual cells, as seen in the higher peak (365-390 nM) and the longer duration (over 10 min). Simultaneous stimulation of CD3 and CD4 did not cause a summation of Ca2+ responses but caused a suppression in the CD3-mediated Ca2+ response. The results support the view that CD4 and CD8 play a role in signal transduction for T cell activation and that the CD4-derived signal interferes with the CD3-derived signal at some stage in the signalling pathway causing the Ca2+ response.

Creatine kinase-MB protein mass is a better indicator for the assessment of acute myocardial infarction in the lower range of creatine kinase level

The theoretical and clinical validity of immunochemiluminometric assay of creatine kinase (CK)-MB protein mass was assessed in patients with acute myocardial infarction and the results were compared with those of immunoinhibition assay of CK activity. Serial changes of both CK-MB protein mass and CK-MB activity were analyzed in 20 consecutive patients. In all 312 samples from 20 patients, protein mass and activity of CK-MB showed good correlation. The exponential fitting of the time-value curve of CK-MB protein mass showed a better correlation coefficient than that of CK-MB activity (0.97 +/- 0.02 vs 0.93 +/- 0.07, p < 0.05), indicating that the CK-MB level measured by the immunochemiluminometric assay was less scattered than that measured by the immunoinhibition method. This finding was most evident at lower CK-MB values (< 500 IU/l). The rate of disappearance from serum of CK-MB protein mass was faster than that of CK-MB activity (0.54 +/- 0.23 hr-1 vs 0.28 +/- 0.13 hr-1, p < 0.001). This may indicate that some amount of the CK-MB activity may be inactivated in the early phase of the release into the serum from the necrotic myocardium. Thus, the immunochemiluminometric assay of CK-MB protein mass has superiority in the diagnosis of acute myocardial infarction compared with the immunoinhibition method, especially when the measured CK-MB level is low. This feature may be useful to distinguish a small myocardial infarction from severe ischemia without myocardial necrosis.

The complete amino acid sequence of subunit d of rat liver mitochondrial H(+)-ATP synthase

Subunit d of H(+)-ATP synthase from rat liver mitochondria was isolated from the purified enzyme by reverse-phase high performance liquid chromatography. The partial amino acid sequence of the subunit was determined by automated Edman degradation of the peptide fragments. The nucleotide sequence of subunit d of rat liver H(+)-ATP synthase was determined from a recombinant cDNA clone isolated by screening a rat hepatoma cell line H4TG cDNA library with a probe DNA. The sequence was composed of 581 nucleotides including a coding region for the import precursor of subunit d and noncoding regions on the 5'- and 3'- sides. The possible precursor of subunit d and its mature polypeptide deduced from the open reading frame consisted of 161 and 160 amino acid residues with molecular weights of 18,763 and 18,631, respectively. Subunit d is a hydrophilic protein with an isoelectric point of 6.19. The sequence of the rat subunit d is highly homologous with that of subunit d of bovine heart and slightly similar to that of the subunit d of the yeast mitochondria. However, it had no homology with the sequence of any of the subunits of bacterial or chloroplast H(+)-ATP synthase.

Determining the site of airway collapse in obstructive sleep apnea with airway pressure monitoring

Twenty patients with obstructive sleep apnea (OSA) underwent complete polysomnography and simultaneous upper airway pressure monitoring with a custom-made, soft silicone-covered catheter measuring 2.3 mm in diameter. The catheter had four solid-state microtip pressure sensors positioned in the posterior nasopharynx, immediately caudal to the tip of the uvula, at the level of the hyoid bone, and in the midesophagus. The level(s) of airway collapse was determined by changes in the pressure patterns between transducers. In 14 of the 20 patients, airway collapse was confined or initiated at the oropharyngeal region. The obstruction extended to the base of tongue in 7 and to the entire collapsible upper airway in 2 patients. Four patients had collapse at the base of the tongue and 2 had collapse at the hypopharynx. The site of airway collapse remained fairly constant through various sleep stages and positions. Uvulopalatopharyngoplasty (UPPP) and postoperative polysomnography were performed in 4 patients (2 with hypopharyngeal, 1 with base of tongue, and 1 with oropharyngeal airway collapse). Two patients had a favorable response to UPPP.

Expression of c-erbB-2 in human esophageal carcinoma cells: overexpression correlated with gene amplification or with GATA-3 transcription factor expression

Amplification and expression of the c-erbB-2 protooncogene was studied in 60 primary human esophageal carcinomas and 12 cell lines established from the carcinomas. Amplification of the c-erbB-2 gene was found in 4 out of 60 (6.7%) and 1 out of 12 (8.3%) DNA samples from the primary carcinomas and cell lines, respectively. Overexpression of c-erbB-2 gene product, as determined by both Northern blot hybridization and immunohistochemical analysis, was found in the cells with c-erbB-2 amplification, but not in normal esophageal mucosae or in primary esophageal carcinomas without gene amplification. In contrast, c-erbB-2 overexpression was clearly observed in 7 cell lines in which gene amplification was not found. We analyzed expression of the GATA-3 transcription factor in the carcinoma cell lines and found that the level of GATA-3 mRNA expression showed very good correlation with that of c-erbB-2 gene expression. This observation suggested that the GATA-3 transcription factor and c-erbB-2 protein play important roles in the process of immortalization and/or maintenance of the transformed phenotype of human esophageal carcinoma cells in vitro.