Does local or global orientation determine the McCollough effect?

In this research, the McCollough effect was observed by using an ambiguous test pattern of coarse gratings made out of fine gratings. Coarse gratings meet at right angles to fine gratings. The global features (coarse gratings) in the test pattern became more salient if the test pattern was blurred, and the frequency of the McCollough effect, corresponding to the global orientation of the test pattern, increased with the increase of the extent of blur. The McCollough effects corresponding to the local orientation of the test pattern occurred frequently if the subjects adapted to fine gratings before viewing the test pattern, whereas the McCollough effects corresponding to the global orientation of the test pattern occurred frequently if the subjects adapted to coarse gratings. Our results indicate that the perceptual organization is an important determinant in the McCollough effect.

Cell cycle-dependent expression and spindle pole localization of a novel human protein kinase, Aik, related to Aurora of Drosophila and yeast Ipl1

Mutations in Aurora of Drosophila and related Saccharomyces cerevisiae Ipl1 kinase are known to cause abnormal chromosome segregation. We have isolated a cDNA encoding a novel human protein kinase of 402 amino acids with a predicted molecular mass of 45.9 kDa, which shares high amino acid identities with the Aurora/Ipl1 protein kinase family; hence the cDNA is designated as aik (aurora/IPL1-related kinase). Amino acid sequence of C-terminal kinase domain of Aik shares 86, 86, 72, 59, and 49% identity with those of Xenopus XLP46APK and XLP46BPK, mouse STK-1, Aurora of Drosophila, and yeast Ipl1, respectively, whereas N-terminal domain of Aik shares high homology only with those of XLP46APK and XLP46BPK. Northern and Western blotting analyses revealed that Aik is expressed highly in testis and various proliferating cells including HeLa cells. In HeLa cells, the endogenous levels of aik mRNA and protein contents are tightly regulated during cell cycle progression. Both of these levels are low in G1/S, accumulate during G2/M, and reduce rapidly after mitosis. Its protein kinase activity is also enhanced at mitosis as inferred by exogenous casein phosphorylation. Immunofluorescence studies using a specific antibody have shown that Aik is localized to the spindle pole during mitosis, especially from prophase through anaphase. These results strongly suggest that Aik is a novel member of a protein kinase family possibly involved in a centrosome function(s) such as chromosome segregation or spindle formation.

Isolation of a T-cell clone showing HLA-DRB1*0405-restricted cytotoxicity for hematopoietic cells in a patient with aplastic anemia

The existence of T cells capable of inhibiting in vitro hematopoiesis has been shown in aplastic anemia (AA), although whether such inhibition is mediated by a specific immune reaction involving an HLA allele remained unknown. We isolated a CD4+ Vbeta21+ T-cell clone that was most dominant among Vbeta21+ T cells in the bone marrow (BM) of an AA patient whose HLA-DRB1 alleles included 1501 and 0405. The T-cell clone named NT4.2 lysed an autologous Epstein-Barr virus-transformed lymphoblastoid cell line (LCL) and phytohemagglutinin-stimulated lymphocytes (PHA-blasts) as well as allogeneic LCLs sharing HLA-DRB1*0405. Cytotoxicity against LCL cells and PHA-blasts by NT4.2 was blocked by anti-HLA-DR monoclonal antibody (MoAb) or anti-CD3 MoAb. NT4.2 also lysed autologous BM mononuclear cells enriched with CD34+ cells that had been cultured for one week in the presence of colony-stimulating factors as well as allogeneic CD34+ cells of a normal individual carrying HLA-DRB1*0405, cultured in the same way. Moreover, NT4.2 strongly inhibited colony formation by hematopoietic progenitor cells derived from cultured CD34+ cells sharing HLA-DRB1*0405. These results indicate that the AA patient has T cells capable of killing hematopoietic cells in an HLA-DRB1*0405-restricted manner and that such cytotoxic T cells may contribute to the pathogenesis of AA.

[Inhibitory effect of oral administration of Takusya on calcium oxalate crystallization in human whole urine]

We previously reported that Takusya had the inhibitory effect on in vitro calcium oxalate crystallization and in vivo stone formation in an animal model and it could be a prophylactic agent against calcium oxalate stone formation. We studied the effect of Takusya on calcium oxalate crystallization in human urine. Takusya (500 mg/day and 1,000 mg/day) was administered to 16 healthy men for 3 days and then 24-hour urine samples were collected to measure the urinary excretion of calcium, phosphate, magnesium, uric acid, creatinine, citric acid and oxalic acid. The urine samples before the administration of Takusya was used as a control. The size and distribution of crystals, which were formed in the urine samples by adding calcium chloride and sodium oxalate, were measured using the Coulter counter technique. Urinary magnesium excretion was significantly reduced by 1,000 mg/day of Takusya compared with the control (p < 0.05). The growth of crystals was significantly inhibited by 500 mg/day of Takusya in the large crystal formers whose urine created crystals more than 3.5 microns before the administration of Takusya (p < 0.05). These findings suggested that Takusya inhibited the growth of crystals formed in human urine.

Performance study of a miniature gamma ray scintillation vivo probe for tumor localization

We have developed a miniature gamma-ray endoscopic probe consisting of dual BGO detector probes for tumor detection inside the body cavities. The dual detector system was coupled with random coincidence to decrease the distant background radiation and to improve its spatial resolution for tumor localization.

METHOD

The performance of the probe was investigated with a point source and a water phantom. A solution of positron emitting 18F isotope was used as the source. Clinical trials of the probe were done to localize tumors on the skin surface of four subjects carrying tumors close to the body surfaces, into whom 67Ga-citrate and 18F-FDG radiopharmaceuticals were injected.

RESULTS

Measurements indicated that the spatial resolution of the dual detector probes is around 1.5 times better than the single detector probe, and both single and dual detector endoscopic probe systems are capable of localizing a tumor on a large photon background.

CONCLUSION

The endoscopic probe may be easier to insert inside body cavities due to the small crystal size and the flexible light guides. A single detector probe with higher sensitivity may be useful in searching for tumors over a wide intracavity area but a dual detector probe can be used for precise tumor localization. The detector probe may also be suitable for intraoperative observation.

Down-regulation of manganese-superoxide dismutase gene expression in idiopathic nephrotic syndrome

An oxidant stress has been shown to prevail in experimental and clinical nephrotic syndrome. Such oxidant stress may be induced by a reduced activity of antioxidant systems. We examined the altered expression of manganese-superoxide dismutase (Mn-SOD), an antioxidant enzyme, in patients with idiopathic nephrotic syndrome, in whom an increased oxidant stress had been demonstrated. The Mn-SOD activities in peripheral blood mononuclear cells obtained from 12 patients with active nephrotic syndrome (6.0 +/- 1.1 years of age, mean +/- SE) and hypoproteinemia were 42% lower (p < 0.05) than in 12 control subjects (5.5 +/- 0.5 years of age) with normal serum total protein concentrations. Reverse-transcriptase polymerase chain reaction also demonstrated that Mn-SOD messenger RNA expression in the patients with nephrotic syndrome was, on average, 59% lower than in control subjects. Because expressions of some genes are sensitive to serum, the serum dependency of Mn-SOD gene transcription was studied in glomerular endothelial cells transfected with a luciferase reporter gene fused with a rat Mn-SOD DNA fragment of -806 to +22 bp of the transcription initiation site (-806:+22). When these cells were exposed to different concentrations of fetal bovine serum (0.5% to 15%), the transcriptional activities determined by luciferase activities were proportional to serum concentrations. This serum-dependent transcriptional activation was also demonstrated by the fragment (-220:+22) but not by the fragment (-220:-20). When glomerular endothelial cells transfected with the fragment (-220:+22) were treated with 5% serum from patients with active nephrotic syndrome, transcriptional activation was more than 80% less than that by 5% serum from control subjects without nephrosis. These results indicate that Mn-SOD gene transcription is regulated at least in part by serum, and that the serum-dependent transcription of the gene is diminished in patients with idiopathic nephrotic syndrome. The regulatory region of serum-dependent gene transcription resides within its early promoter region. Our findings suggest that down-regulation of antioxidant enzyme transcription may contribute increased oxidant stress in idiopathic nephrotic syndrome.

Influence of chemotherapy on FDG uptake by human cancer xenografts in nude mice

This study evaluated the use of PET with 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) for monitoring chemotherapy effects, using a human cancer xenograft (poorly differentiated human gastric cancer) in vivo model.

METHODS

Tumor 18F-FDG uptakes and sizes were measured after administrating mitomycin (MMC), cisplatin (CDDP) and adriamycin (ADR) to xenograft-bearing nude mice and compared with 18F-FDG tumor uptake and tumor size in a non-therapy group. The correlation between the uptake and size was also assessed.

RESULTS

The largest reduction in tumor size after chemotherapy occurred in the MMC administered group, followed by the CDDP case, with no reduction in the ADR group as compared to the controls. Fluorine-18-FDG tumor uptake after chemotherapy was also decreased in the MMC and CDDP groups, in that order, but not in the ADR case. With MMC and CDDP, size reduction became significant on Days 8 or 11, whereas 18F-FDG tumor uptake had already been decreased on Days 3 or 7.

CONCLUSION

Fluorine-18-FDG uptake decreases in parallel to the efficacy of anticancer agents and correlates with subsequent morphologic changes. We conclude that 18F-FDG PET tumor images are indeed useful for monitoring the effects of cancer chemotherapy.

Immunohistochemical studies on matrix metalloproteinase-9 (MMP-9) and type-IV collagen in endometrial carcinoma

Immunohistochemical staining of MMP-9 and the type-IV collagen was performed on paraffin sections of endometrial carcinoma. Immunostaining in 129 cases of endometrial cancer detected MMP-9 in 19.0% of the cases. MMP-9 positive was shown in 30% of the cases with vessel invasion, and in 12.7% of the cases without vessel invasion (p < 0.05). MMP-9 showed positive in many cases with poor differentiation and lymph node metastasis, but still failed to achieve statistical significance. MMP-9 staining did not correlate with disease outcomes. We can not clarify that MMP-9 is associated with tumor-cell invasion and metastasis. Type-IV collagen deposition at the tumor-stromal border was studied in 58 cases of endometrial carcinoma in which disruptions were seen in varying degrees. The type-IV collagen in the primary lesion decreased as the differentiation decreased. Even in the lymph node metastasis lesions, the type-IV collagen was stained and was almost in agreement with the primary lesions. In the primary lesions, there was no relationship between MMP-9 staining and the type-IV collagen. It was suggested that the type-IV collagen observed in endometrial carcinoma was more concerned with the differentiation of the tumor than with the degradation by MMP-9.

Disposition and metabolism of the new oral antidiabetic drug troglitazone in rats, mice and dogs

The pharmacokinetics of troglitazone (CAS 97322-87-7, CS-045), a new oral antidiabetic drug for the treatment of non-insulin-dependent diabetes mellitus (NIDDM), were investigated in rats, mice and dogs following oral and intravenous administration of 14C-labeled troglitazone at doses of 5 mg/kg. The absorption rates, calculated from the AUC ratios of total radioactivity after oral and intravenous administration, or from the biliary excretion rate after intraduodenal administration in rats were both as high as 75%. High uptake by the liver, one of the pharmacological target organs, was demonstrated in both rats and mice. Furthermore, in the KK mouse, an obese NIDDM model animal, the radioactivity was incorporated selectively as troglitazone itself to muscle, the peripheral target organ. Troglitazone reversibly bound to serum albumin with a high ratio (> 99%). Troglitazone was mostly metabolized to the conjugates: sulfate (M 1) and glucuronide (M 2). The oxidized metabolite, a quinone-type metabolite (M 3), was found to be further metabolized to the sulfate (U 2). The biliary excretion rates of these conjugates were high in each animal, and the occurrence of enterohepatic circulation of the conjugates was also suggested. Sex differences in pharmacokinetics were observed in rats; i.e. females showed a higher plasma concentration of troglitazone, and a lower concentration of M 1, than males, and they excreted the sex-related metabolite, a hydroxylated M 1 (U 1), in the bile.

Fluid resuscitation and systemic complications in crush syndrome: 14 Hanshin-Awaji earthquake patients

BACKGROUND

Crush syndrome is a form of traumatic rhabdomyolysis characterized by systemic involvement, in which acute renal failure is potentially life-threatening.

METHODS

Clinical and laboratory data of 14 crush-syndrome patients transferred to a tertiary emergency department after the Hanshin-Awaji earthquake were analyzed. The patients were buried under collapsed houses for the average of 6.7 +/- 5.7 (SD) hours (range, 1 to 24 hours). They were referred to us 6 to 250 hours after the earthquake.

RESULTS

Of those who arrived at our institution within 40 hours, 25% (two of eight) developed renal failure, whereas all six patients who arrived after 40 hours developed renal failure. Peak serum creatine kinase ranged from 6,677 to 134,200 U/L (51,674 +/- 41,776). Renal failure was highly associated with massive muscle damage (serum creatine kinase above 25,000 U/L) and insufficient initial fluid resuscitation (below 10,000 mL/2 days).

CONCLUSIONS

Prompt and adequate, if not massive, fluid resuscitation is the key to preventing renal failure after such injury.

Interleukin-6 secreting phaeochromocytoma associated with clinical markers of inflammation

Phaeochromocytomas have been shown to produce not only catecholamines but other neuropeptides and hormones, with a variety of clinical manifestations. We report a 70-year-old female patient with phaeochromocytoma exhibiting sustained hypertension, low-grade fever, thrombocytosis, and elevated levels of plasma fibrinogen and C-reactive protein. Serum interleukin (IL)-6 levels were significantly elevated, whereas serum IL-1 alpha and IL-1 beta were not detectable. After surgical removal of the tumour, hypertension and low-grade fever disappeared, and the laboratory finding including serum IL-6 concentrations became normal. Immunohistochemical study of the tumour showed positive staining for IL-6. Culture of the resected tumour revealed the production of large amounts of IL-6. It is suggested that IL-6 secreted by the tumour was responsible for some of the clinical manifestations in this patient.

Therapeutic effect of cytomedicine on mesangio-proliferative glomerulonephritis in human interleukin-6 transgenic mice

We previously demonstrated that IgG1 plasmacytosis in human interleukin-6 transgenic mice (hIL-6 Tgm) was suppressed by the implantation of SK2 hybridoma cells (SK2 cells, which secrete anti-hIL-6 monoclonal antibodies) microencapsulated in a semipermeable and biocompatible device. In this study, we demonstrated that the mesangio-proliferative glomerulonephritis in hIL-6 Tgm was also improved by the same treatment. These results strongly support the concept of cytomedicine, which is a novel drug delivery system (DDS) using living cells. However, an electron microscopy study showed that cytomedicine has a limited duration of effectiveness because of the disappearance of space for cell proliferation in the microcapsule. Thus, the control of cell proliferation in a device must be developed to prolong the function and effectiveness of cytomedicine.

Oxygen-dependent fragmentation of cellular DNA by nitric oxide

Although active oxygen species and related metabolites, such as nitric oxide (NO), have been postulated to play important roles in the apoptosis of various cells, a precise mechanism leading to cell death remains to be elucidated. Recently we found that the lifetime of NO depends greatly on the concentration of environmental oxygen and that NO reversibly inhibits mitochondrial respiration and ATP synthesis; the inhibitory effect is stronger at physiologically low oxygen tension than under atmospheric conditions (Arch. Biochem. Biophys. 323, 27-32, 1995). The present work describes the effects of the NO-generating agent, 1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC 18) and oxygen tension on the respiration, ATP synthesis and apoptosis of HL-60 cells. When respiration was inhibited by NOC 18, cellular ATP levels decreased significantly and DNA fragmentation was elicited. Both events were enhanced by decreasing oxygen tension and suppressed by adding NO-trapping agents, such as 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) and oxyhemoglobin. The fragmentation of cellular DNA was inhibited in a dose dependent manner by herbimycin A, a tyrosine kinase inhibitor. Fragmentation of the DNA of HL-60 cells was also induced either by peroxynitrite, superoxide or hydroxyl radical by some mechanism which was diminished by lowering the oxygen tension. These results indicated that the decrease in cellular ATP and activation of tyrosine kinase might play important roles in NO-induced apoptosis particularly under physiologically low oxygen tensions.

Analysis of 372 patients with Crush syndrome caused by the Hanshin-Awaji earthquake

OBJECTIVE

To clarify clinical features and determine the severity of injuries in patients with crush syndrome in Hanshin-Awaji earthquake.

METHODS

We retrospectively reviewed medical records of 6,107 patients hospitalized in 95 hospitals, and identified 372 patients with crush syndrome.

RESULTS

The major sites of crush injury were in the lower extremities (74%), followed by the upper extremities (10%), and the trunk (9%). Pelvic fractures, limb fractures, and abdominal injuries were the most frequently associated injury. Patients with trunk compression and/or with abdominal injury had a higher mortality rate. A total of 50 patients (13.4%) died. The causes of death within 5 days after the earthquake were hypovolemia and hyperkalemia. Peak serum creatine kinase concentration increased with the number of crushed extremities. Mortality and the risk of acute renal failure were higher in patients with creatine kinase concentration more than 75,000 micro/L.

CONCLUSIONS

Peak serum concentration of creatine kinase as well as the number of injured extremities serve to estimate the severity of crush syndrome.

Inhibition by 1-aminocyclobutane-1-carboxylate of the activity of 1-aminocyclopropane-1-carboxylate oxidase obtained from senescing petals of carnation (Dianthus caryophyllus L.) flowers

We partially purified 1-aminocyclopropane-1-carboxylate (ACC) oxidase from senescing petals of carnation (Dianthus caryophyllus L. cv. Nora) flowers and investigated its general characteristics, and, in particular, the inhibition of its activity by ACC analogs. The enzyme had an optimum pH at 7-7.5 and required Fe2+, ascorbate and NaHCO3 for its maximal activity. The Km for ACC was calculated as 111-125 microM in the presence of NaHCO3. Its M(r) was estimated to be 35 and 36 kDa by gel-filtration chromatography on HPLC and SDS-PAGE, respectively, indicating that the enzyme exists in a monomeric form. These properties were in agreement with those reported previously with ACC oxidases from different plant tissues including senescing carnation petals. Among six ACC analogs tested, 1-aminocyclobutane-1-carboxylate (ACBC) inhibited most severely the activity of ACC oxidase from carnation petals. ACBC acted as a competitive inhibitor with the Ki of 20-30 microM. The comparison between the Km for ACC and the Ki for ACBC indicated that ACBC had an affinity which was ca. 5-fold higher than that of ACC. Whereas ACC inactivated carnation ACC oxidase in a time-dependent manner during incubation, ACBC did not cause the inactivation of the enzyme. Preliminary experiments showed that ACBC and its N-substituted derivatives delayed the onset of senescence in cut carnation flowers.

Quantitative analysis of the usage of human T cell receptor alpha and beta chain variable regions by reverse dot blot hybridization

We previously developed an adaptor ligation-mediated PCR method to amplify the T cell receptor (TCR) cDNA pools. In the present study we applied reverse dot blot hybridization to PCR-amplified specimens for quantitative analysis of the usage of TCR alpha and beta chain variable (V) region. 44 VA sequence-specific oligonucleotide probes (SSOPs) and 38 VB SSOPs were synthesized corresponding to unique sequences of VA and VB subfamilies. Peripheral blood lymphocytes of ten healthy donors and five T cell clones established from bone marrow cells were examined for VA and VB usage using this method. The results were consistent with those obtained by a colony hybridization method and those by immunofluorescence staining using monoclonal antibodies to VA and VB. Thus, reverse dot blot hybridization for TCR V(alpha) and Vbeta is a new, easy and dependable technique useful for analysis of VA and VB usage by human T cells.

Cytomedical therapy for IgG1 plasmacytosis in human interleukin-6 transgenic mice using hybridoma cells microencapsulated in alginate-poly(L)lysine-alginate membrane

Cytomedical therapy for human interleukin-6 transgenic mice (hIL-6 Tgm) was implemented by the intraperitoneal injection of alginate-poly(L)lysine-alginate (APA) membranes microencapsulating SK2 hybridoma cells (APA-SK2 cells) which secrete anti-hIL-6 monoclonal antibodies (SK2 mAb). IgG1 plasmacytosis in the hIL-6 Tgm was suppressed by a single injection of APA-SK2 cells, and the survival time of these mice was remarkably prolonged. The viable cell number and the SK2 mAb-secretion of APA-SK2 cells increased for at least one month both under culture conditions and in allogeneic recipients (in vivo). Moreover, SK2 mAb which were secreted from APA-SK2 cells injected into allogeneic recipients was detected in serum at high concentrations; 3-5 mg/ml from day 14 to day 50 post-injection. In contrast, the injection of free SK2 cells had no therapeutic effect on hIL-6 Tgm. These results strongly suggest that APA membranes microencapsulating cells which were modified to secrete molecules useful for the treatment of a disorder were effective as an in vivo long-term delivery system of bioactive molecules, as 'cytomedicine'.

Patterns of inspiratory muscle shortening during hypoxia and hypercapnia in dogs

The shortening of parasternal intercostal muscles (Para) and crural (Cru) and costal diaphragms (Cos) are not precisely understood. We therefore examined shortening patterns of these inspiratory muscles by using chronically implanted sonomicrometers in dogs. To avoid acute effects of surgery, measurements were performed 3 weeks after implanting the sonomicrometers. Patterns of length changes of Para, Cru, and Cos were measured during hypoxia and hypercapnia under two levels of anaesthesia. Respiratory length change (delta L) was assessed as a percentage change relative to the resting length at functional residual capacity (LFRC). Peak tidal shortening was defined as the maximal change from LFRC (delta L/LFRC). Under light anesthesia, the delta L/LFRC was the same among the three muscle groups at all tidal volumes (VT). Under deep anaesthesia, the delta L/LFRC both of Cru and Cos exceeded that of Para. Under light anaesthesia, the maximal shortening velocity ((delta L/LFRC)/delta t) of Cru was greater than that of Para. Under deep anaesthesia, the (delta L/LFRC)/delta t of Para was exceeded by that both of Cru and Cos. Furthermore, the (delta L/LFRC)/delta t of each inspiratory muscle was greater during hypoxia than during hypercapnia at equal volume. We conclude that: 1) the contribution of the diaphragm to ventilation increases during deep anaesthesia; 2) the muscle shortening velocity during hypoxia or hypercapnia is lower in parasternal intercostal muscles than in the diaphragm; and 3) there is no difference in the shortening pattern between crural and costal diaphragms.

Immunological studies of SK2 hybridoma cells microencapsulated with alginate-poly(L)lysine-alginate (APA) membrane following allogeneic transplantation

Microencapsulation of living cells or tissues has been proposed to prevent their immune destruction following transplantation. In this study, we examined whether SK2 hybridoma cells microencapsulated in an alginate-poly(L)lysine-alginate (APA) membrane (APA-SK2 cells) were immunoisolated from the allogeneic host's immune system using a cytotoxicity test. The APA membrane inhibited the activation of the host's cellular immune response, but did not prevent the production of cytotoxic antibodies against entrapped SK2 cells following allogeneic transplantation. However, the APA-SK2 cells remained vital in SK2 cell-immunized mice as well as in intact mice. We considered that complement regulatory factors which were present on cell membrane and had species-specific restriction blocked the complement-mediated cell lysis on allogeneic transplantation, since APA-SK2 cells were destroyed by rabbit anti-SK2 cell antiserum. Our results demonstrated that APA membrane could inhibit cell-cell contact between entrapped cells and the host's lymphocytes, but could not completely protect the entrapped cells from xenogeneic humoral immunity.

Mild mitral regurgitation reduces exercise capacity in patients with idiopathic dilated cardiomyopathy

We evaluated 30 patients with dilated cardiomyopathy (New York Heart Association functional Class II or III with medical treatment) to assess the effect of mild mitral regurgitation (MR) on exercise capacity in patients with congestive heart failure. They were classified into two groups based on results of left ventriculography: MR present (n = 10) and MR absent (n = 20). The severity of the MR by left ventriculography was grade I (mild) in all patients with MR. Steady-state hemodynamic data and angiographic data did not differ significantly between the two groups. Heart rate and systolic blood pressure at rest and in response to symptom-limited exercise testing did not differ between the groups. However, the peak work load was significantly lower in the group with MR than that in the group without MR (101 +/- 32 vs. 142 +/- 29 W, respectively; p < 0.005). Peak oxygen uptake and peak oxygen pulse were also significantly lower in the group with MR than in that without MR (peak oxygen uptake: 18 +/- 23 +/- 5 ml/min/kg; p < 0.05, peak oxygen pulse: 6.6 +/- 2.6 vs. 9.5 +/- 2.7 ml/min/beat: p < 0.01, respectively). Thus, mild MR had a detrimental effect on the exercise capacity in patients with dilated cardiomyopathy.

Pyruvate dehydrogenase complex-catalyzed formation of N-arylacetohydroxamic acids from nitroso aromatic compounds in rat isolated cells and perfused organs

The formation of N-arylacetohydroxamic acid derivatives from m-nitrosobenzyl alcohol (MBNO) and a nitroso derivative of chloramphenicol, 2,2-dichloro-N-[2-hydroxy-1-(hydroxymethyl)-2-(4-nitrosophenyl) ethyl]acetamide, in the presence of pyruvate was investigated with rat isolated cells (heart, kidney, liver, small intestine, lung, bone marrow and spermatozoa) and perfused organs (liver and heart). The activity in N-(m-hydroxymethylphenyl) acetohydroxamic acid (MBHA) formation was found in all the cells tested. Measurement of the kinetic parameters revealed that K(m) values of MBNO were ca. 0.3 mM and that the order of Vmax per cell was heart > kidney > liver > small intestine. In the hepatocytes, MBHA was metabolized further and the in vitro intrinsic clearance of MBHA was 1.91 +/- 0.24 ml/min/10(8) cells. In a single-pass perfusion of rat liver with MBNO, the corresponding amino, acetylamino and azoxy derivatives and unknown materials were formed in addition to MBHA. The activity in MBHA formation was increased by the addition of both diethyl maleate and paraoxon. In a recirculating perfusion of rat liver with MBNO, however, the net MBHA formation was hardly detected, because of the disposition of MBHA formed. The hepatic clearance of MBHA was 1.15 +/- 0.06 ml/min/g of liver. In a recirculating perfusion of isolated rat heart with MBNO, MBHA was formed as a major metabolite and further biotransformation was not found. The N-arylacetohydroxamic acid derivative of 2,2-dichloro-N-[2-hydroxy-1-(hydroxymethyl)-2-(4-nitrosophenyl) ethyl]acetamide was also formed in rat bone marrow cells and the isolated perfused heart. These results indicate that the formation of N-arylacetohydroxamic acids from nitroso aromatic compounds and pyruvate catalyzed by pyruvate dehydrogenase complex proceeds in virtually all mammalian tissues.

Pulmonary interstitial emphysema during piston-type high-frequency oscillatory ventilation

We retrospectively reviewed data on high frequency oscillatory ventilation (HFOV) settings and pulmonary function in 14 extremely low birth weight infants who were treated with piston-type HFOV immediately after birth for severe respiratory distress to investigate the cause of pulmonary interstitial emphysema (PIE) associated with HFOV. PIE developed a mean of 23 hr after the initiation of HFOV in 6 infants. Eight infants did not develop PIE and served as the control group. The lowest mean airway pressure (MAP) in the PIE group, which occurred immediately before disease onset was 5.2 cm H2O. The lowest MAP in the control group was 7.5 cm H2O (p < 0.01), which occurred immediately before the ventilatory mode was changed from HFOV to conventional mechanical ventilation for weaning from mechanical ventilation. Respiratory system compliance (Crs) 12 hr after birth was below normal in both groups and there was no significant difference between groups. These results suggest that an unusually low MAP may contribute to PIE during piston-type HFOV in the presence of low Crs. It is therefore important to maintain a high MAP during HFOV until pulmonary compliance becomes normal.