Effects of exercise and CO2 inhalation on intersubject variability in ventilatory and heart rate responses to progressive hypoxia

Although the ventilatory and heart rate responses to hypoxia are known to vary widely among subjects, it is not known how exercise or hypercapnia influence the intersubject variability of these responses. If the intersubject variability increases under such conditions, the inherent response of individuals will have more impact on ventilation and heart rate under a variety of hypoxic conditions during exercise or with hypercapnia than at rest or with normocapnia. Seventeen healthy male volunteers underwent tests to measure ventilatory response to isocapnic progressive hypoxia three times respectively: at rest; during CO2 inhalation (end-tidal carbon dioxide tension (PET,CO2) raised by 5 torr from the baseline level); and during mild exercise with a cycle ergometer (12.5 W) in a supine position. The mean (SEM) value of hypoxic ventilatory response (HVR) (delta minute ventilation (V'E)/delta arterial oxygen saturation (Sa,O2) was significantly increased both in the exercise and hypercapnic runs compared with that in the control run (0.45 +/- 0.12, 0.34 +/- 0.08, respectively, vs 0.12 +/- 0.02 L.min-1/% fall), although the respiratory pattern was different under the two loaded conditions. The intersubject variation in HVR was also significantly increased during the two loaded conditions compared with the control, although a significant correlation remained between the control value and that obtained during either loaded condition (r = 0.66 and r = 0.60, respectively). The heart rate (HR) response evaluated by the slope factor (delta HR/delta Sa,O2) was not significantly different either in the mean value or in the intersubject variability among the three experimental conditions. In conclusion, exercise or CO2 inhalation not only increase the slope value of HVR but also amplify the intersubject variability of the response. In contrast, the HR response to hypoxia evaluated as a slope factor does not change with exercise or CO2 inhalation.

Cold activation of complement in sera from patients with persistent hepatitis C virus infection on interferon therapy

The loss of haemolytic activity in sera during storage at low temperature (the cold activation of complement) was observed in 136 of 184 (74%) patients with chronic liver disease associated with hepatitis C virus (HCV) infection. This was more frequent than observed in the three of 40 (8%) patients with chronic hepatitis B (P < 0.001) or none in 43 normal controls (P < 0.001). Of 103 patients with chronic hepatitis C who had completed a full course of recombinant interferon-alpha 2a therapy (total dose: 516 x 10(6) U), 40 responded completely and 21 responded partially, as judged by the normalization or decrease of alanine aminotransferase levels 6 months after the completion of therapy; 42 patients did not respond at all. The cold activation of complement persisted in five (13%) complete responders, less often than in 33 (79%) non-responders (P < 0.001). At the completion of interferon therapy, the cold activation of complement persisted in 12 of 54 patients despite the normalization of alanine aminotransferase. Spontaneous exacerbation of hepatitis occurred in seven of 12 (58%) patients with cold activation, which was more frequent than in the four of 42 patients (10%) without it (P < 0.01). The cold activation of complement disappeared along with the loss of HCV-RNA in five of six responders during the 6 month period after the completion of interferon therapy, while both cold activation and HCV-RNA persisted in all eight non-responders. These results indicate that the cold activation of complement may be useful as a marker of HCV viraemia for monitoring the response to interferon in patients with HCV infection.

Negative inotropic action of denbufylline through interfering with the calcium channel independently of its PDE IV inhibitory activity in guinea pig ventricle papillary muscles

The inotropic actions of xanthine derivatives with long alkyl chains were investigated in guinea pig ventricular papillary muscle. A potent and nonselective phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine, elicited a positive inotropy and inhibited the negative inotropic effects of calcium channel inhibitors, as did a selective PDE III inhibitor, amrinone, and these effects were canceled by a protein kinase inhibitor, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89). However, 1,3-di-n-butyl-7-(2'oxopropyl)xanthine (denbufylline) and 1-n-butyl-3-n-propylxanthine (XT-044), which have potent and selective PDE IV-inhibitory activities, showed negative inotropic actions that became more potent in the presence of H-89. Denbufylline abolished the late restoration phase induced by ryanodine. This xanthine derivative attenuated the effects of both the calcium channel acting agents Bay K 8644 and verapamil, without interaction with caffeine and dihydropyridine calcium channel inhibitors, and denbufylline had little direct influence on the specific binding of [(3)H]azidopine and [(3)H]desmethoxyverapamil to cardiac membranes. A nonxanthine PDE IV inhibitor, Ro 20-1724, did not affect the inotropic actions of calcium channel inhibitors. The attenuation by denbufylline or XT-044 of the negative inotropic action of verapamil was not influenced by treatment with H-89. These results suggest that in the ventricular papillary muscle, these xanthine derivatives elicit negative inotropy by acting on a verapamil-sensitive site of the calcium channel without involving their PDE-inhibitory activity.

Evaluation of retinal microcirculatory alterations in the Goto-Kakizaki rat. A spontaneous model of non-insulin-dependent diabetes

PURPOSE

To evaluate retinal microcirculation in the spontaneous diabetic GK (Goto-Kakizaki) rat over an extended time.

METHODS

The dye-dilution technique with scanning laser ophthalmoscope-based fluorescein angiography was used to evaluate retinal circulation in GK rats with diabetes of 1, 3, and 5 months' duration and in age-matched controls. Scanning laser ophthalmoscope fluorescein angiograms were recorded after a 10-microliter bolus of 10% sodium fluorescein was injected into the tail vein, followed by a flush of 0.1 ml saline. Retinal mean circulation times (MCTs), vessel diameters, and retinal segmental blood flows (SBFs) were determined using computer-assisted image analysis on a frame-by-frame basis.

RESULTS

The MCTs were significantly prolonged (P< 0.01) in the GK rat groups (2.60 +/- 0.31, 2.74 +/- 0.28, and 2.84 +/- 0.38 seconds at 1, 3, and 5 months' duration of diabetes, respectively) compared to the age-matched controls (1.94 +/- 0.20, 1.99 +/- 0.12, and 1.91 +/- 0.22 seconds, respectively). No significant differences were observed in the retinal arterial and venous diameters between groups at each time period. The SBFs were significantly reduced (P< 0.03) in the GK rat groups (12.0 +/- 1.5, 12.1 +/- 2.0, and 11.8 +/- 2.5 x 10(2) micrometer squared/second at 1, 3, and 5 months' duration of diabetes, respectively) compared to the controls (16.0 +/- 2.2, 16.7 +/- 1.8, and 17.2 +/- 2.5 x 10(2) micrometer squared/second, respectively). In either group, no significant changes with growth were observed in MCT, vessel diameters, or SBF, although the MCTs in the GK rat group tended to lengthen, and arterial and venous diameters in the GK rat group tended to increase with duration of diabetes. Goto-Kakizaki rats did not exhibit dense cataracts, the retinal circulation could be observed, and morphologic changes of diabetic retinopathy did not develop throughout the experimental period.

CONCLUSIONS

A significant prolongation in MCT and a significant reduction in SBF appeared in GK rats at an early stage in diabetes. This tendency continued until 5 months' duration of diabetes. These results suggest that retinal circulatory abnormalities are found before observable retinopathy development in GK rats and that there may be some mechanism causing a reduction in SBF without changing major retinal vessel diameters at an early stage in non-insulin-dependent diabetes mellitus (NIDDM). In addition, this study demonstrates that the GK rat will be a useful model of non-insulin-dependent diabetes mellitus to evaluate retinal circulation over an extended time.

Effects of hypergravity on growth and cell wall properties of cress hypocotyls

Elongation growth of etiolated hypocotyls of cress (Lepidium sativum L.) was suppressed when they were exposed to basipetal hypergravity at 35 x g and above. Acceleration at 135 x g caused a decrease in the mechanical extensibility and an increase in the minimum stress-relaxation time of the cell wall. Such changes in the mechanical properties of the cell wall were prominent in the lower regions of hypocotyls. The amounts of cell wall polysaccharides per unit length of hypocotyls increased under the hypergravity condition and, in particular, the increase in the amount of cellulose in the lower regions was conspicuous. Hypergravity did not influence the neutral sugar composition of either the pectin or the hemicellulose fraction. The amount of lignin was also increased by hypergravity treatment, although the level was low. The data suggest that hypergravity modifies the metabolism of cell wall components and thus makes the cell wall thick and rigid, thereby inhibiting elongation growth of cress hypocotyls. These changes may contribute to the plants' ability to sustain their structures against hypergravity.

Plant growth processes in Arabidopsis under microgravity conditions simulated by a clinostat

The life cycle of Arabidopsis plants was examined by growing them on a horizontal clinostat. Seeds on agar media were allowed to germinate and seedlings were grown under a simulated microgravity on a horizontal clinostat. Clinorotation (3 rpm) did not appear to interfere with germination of plant seeds and development of cotyledons and leaves. Stress relaxation parameters of the cell wall, the minimum relaxation time and the relaxation rate did not appear to be affected by clinostat rotation. On the other hand, the length of inflorescences was reduced to 61-62% by clinostat rotation. Rotation was found to inhibit the polar transport of auxin, although inflorescence growth and auxin transport were not completely inhibited. From these facts, it is possible that the life cycle in Arabidopsis plants could be accomplished in space, although growth phenomena involving auxin transport and its action may be disturbed. Plants may have a capacity to grow in space and we may be able to cultivate crops in space.

Protection of rabbits against HTLV-II infection with a synthetic peptide corresponding to HTLV-II neutralization region

Rabbit immune sera raised against synthetic peptides of the HTLV-II envelope gp46 region were examined for HTLV-II neutralization ability by HTLV-vesicular stomatitis virus (VSV) pseudotype assay and syncytium inhibition assay. HTLV-II neutralization activity was detected in the sera against HTLV-II Env gp46, 80-103 but not in those to HTLV-II Env gp46, 171-196. Three rabbits immunized with the synthetic peptide of HTLV-II Env gp46, 80-103 and three non-immunized rabbits were challenged with intravenous inoculation of an HTLV-II-producing human cell line (MOT, 1 x 10(7) cells). The non-immunized rabbits showed seroconversion for HTLV-II after 2 weeks and maintained persistent infection but the immunized rabbits were protected from HTLV-II infection. Nested or repeated polymerase chain reaction revealed the presence of HTLV-II provirus sequences in the non-immunized rabbits but not in the immunized rabbits. These results suggest that peptide vaccination with a synthetic peptide corresponding to the HTLV-II neutralization region is useful for preventing HTLV-II infection.

The basic amino acid transporter (rBAT)-like immunoreactivity in paraventricular and supraoptic magnocellular neurons of the rat hypothalamus

In the rat hypothalamus, the basic amino acid transporter (rBAT)-like immunoreactivity was analyzed by immunohistochemistry using an antibody against the 15-amino acid sequence of the deduced rat rBAT protein. In the supraoptic and the paraventricular nuclei, magnocellular neurons exhibited the marked rBAT-like immunoreactivity in intracellular structures but not in the plasma membrane. The results suggest that the rBAT serves as an intracellular amino acid transport system in magnocellular neurons.

Sequence, tissue distribution and developmental changes in rat intestinal oligopeptide transporter

Complementary DNA clones encoding the rat PepT1 small-intestinal oligopeptide transporter were isolated from a jejunal library by cross-hybridization with a rabbit PepT1 cDNA probe. The cDNA sequence indicates that rat PepT1 is composed of 710 amino acids and shows 77% and 83% amino acid sequence identity with rabbit and human PepT1, respectively. Northern blot analysis detected rat PepT1 mRNA in the small intestine and kidney. Intestinal PepT1 mRNA levels were highest in 4-day old rats, and then decreased reaching the adult level by day 28 after birth. These results indicate that the expressions of PepT1 gene change markedly during development.

Effects of M1-selective antimuscarinics on respiratory chemosensitivity in humans

We examined effects of selective M1 antagonists on hypercapnic and hypoxic ventilatory responses in 17 healthy human volunteers. Subjects were intravenously treated with placebo, pirenzepine (10 mg) and biperiden lactate (4 mg) on three separate days in a randomized double-blind design. Ventilatory responses to hyperoxic progressive hypercapnia and isocapnic progressive hypoxia were studied after the drug administration. There were no statistically significant differences in the mean delta VE/delta PET CO2 or delta VE/delta SaO2 among the three treatments. However, the delta VE/delta PET CO2 with placebo negatively correlated with the difference in delta VE/delta PET CO2 between the biperiden and placebo studies (r=-0.65, P < 0.01), but not with that between the pirenzepine and placebo studies. On the other hand, the delta VE/delta SaO2 with placebo negatively correlated with the difference in delta VE/delta SaO2 between the pirenzepine and placebo studies (r = -0.79, P < 0.001), but not with that between the biperiden and placebo studies. These data suggest the possible involvement of M1 cholinergic receptors in the central CO2 and peripheral O2 sensing mechanisms in humans, although the degree of its involvement is not consistent among subjects. These findings may explain the interindividual variation in the control of breathing in humans.

Changes of unmyelinated nerve fibers in sural nerve in amyotrophic lateral sclerosis, Parkinson's disease and multiple system atrophy

Quantitative changes in unmyelinated nerve fibers (UMNFs) of sural nerves in patients of amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD) and multiple system atrophy (MSA) were evaluated using autopsy materials whose pathological diagnosis had been confirmed by careful postmortem examinations. Ordinary ALS cases demonstrated no involvement in cutaneous UMNFs; however, the patients with long survival due to the application of ventilatory support showed bimodality in UMNF diameter histograms, and a patient with involvement of systems other than motor pathways showed an abnormal value in two indices: a low percentage of subunits containing axon(s) and a high mean number of Schwann cell profiles per axon. A significant reduction of the mean value of UMNF density (21%) was found in PD patients. Because the density of myelinated nerve fibers did not show any significant decrease as compared with age-matched controls, the change of nerve fibers in peripheral nervous system was considered to be confined to UMNFs in PD. Elderly PD cases showed enhanced changes in the ageing process, as expressed by the two indices described above. In MSA, the mean value of UMNF density was significantly decreased (23%), and this decrease almost paralleled that of myelinated nerve fiber density. Abnormal values for the two indices described above were found and two out of four cases demonstrated bimodality in the diameter histogram of UMNFs. Unlike MSA, ALS and PD have not been included in the disorders with cutaneous UMNF involvement. Our results supply the first evidence of morphological changes in cutaneous UMNFs in PD cases. In ordinary ALS cases, the emergence of such morphological changes is suggested in cases with long survival.

The effect of lazaroid (U74500A), a novel inhibitor of lipid peroxidation, on 24-hour heart preservation. A study based on a working model using cross-circulated blood-perfused rabbit hearts

Lazaroid, an inhibitor of iron-mediated lipid peroxidation, has been shown to reduce free radical-mediated injury after ischemia and reperfusion. We thus examined the efficacy of pretreatment with lazaroid (U74500A) in enhancing functional recovery after 24-hr heart preservation. An isolated rabbit heart model perfused with the blood from a support rabbit was used. Before preservation, either U74500A (4 mg/kg, group L; n = 6) or solvent (group S; n = 7) was given to the donor rabbit. After 24-hr preservation with UW solution at 0 degrees C, all hearts were perfused with cross-circulated blood for 60 min with the Langendorff mode followed by 40 min of the working mode. In group S, ventricular fibrillation (Vf) after reperfusion was observed in all hearts, whereas no Vf was observed in the U74500A-pretreated group. In group L, the serum creatine phosphokinase; its isozyme, troponin-T; and serum lipid peroxide levels after 10 min of reperfusion were all significantly (P < 0.05) lower than those in group S. The Frank-Starling curve (indicating the left atrial pressure-aortic flow relationship) showed a significant left and upward shift in group L compared with that in group S (P < 0.0001). The heart pretreated with U74500A showed less ischemia-reperfusion injury, better ventricular function, and a lower lipid peroxide level. We thus conclude that the inhibition of lipid peroxidation with lazaroid appears to offer some potential benefits for long-term heart preservation.

Effects of sho-saiko-to on production of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and superoxide from peripheral monocytes and polymorphonuclear cells isolated from HIV infected individuals

The effects of Sho-saiko-to (SST), a traditional Chinese medicine, on the production of PGE2 from monocytes, LTB4 and superoxide from polymorphonuclear cells (PMNC) in HIV infected individuals were studied. SST inhibited the production of PGE2 from monocytes stimulated by opsonized zymosan in all groups including the healthy control group and also inhibited the production of superoxide from PMNC after stimulation with FMLP. On the other hand, SST enhanced the production of LTB4 when PMNC were stimulated by the calcium ionophore A23187. These results suggest that SST has different effects on the production of prostanoids or superoxide from monocytes and PMNC. Furthermore, our data indicates that inhibition of PGE2 or superoxide production will lead to indirect suppression of HIV, and enhancement of LTB4 will contribute to the upregulation of the immune reaction in HIV infected individuals.

Leukocyte function-associated antigen-1-dependent adhesion of rat ascites hepatoma AH66F to mesentery-derived mesothelial cells

Rat ascites hepatoma AH66F cells adhered better than AH130 cells to mesentery-derived mesothelial cells (M-cells), though both cells secreted Mr 92,000 matrix metalloproteinase on a gelatin zymogram with similar activity. AH66F cells expressed leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1), a ligand of LFA-1, on the cell surface, while AH130 cells had ICAM-1 alone. The adhesion of M-cells of AH66F cells was inhibited to the adhesion level of AH130 cells by anti-rat LFA-1 alpha -and/or beta-chain monoclonal antibody (mAb) and also by anti-rat ICAM-1 mAb. This is the first report to show the LFA-1-dependent adhesion of cells other than leukocytes, because AH66F cells did not express CD45, T cell-alpha beta receptor or Cd11b/c (Mac-1/p150,95). These results indicate that a part of the adhesion of AH66F cells to M-cells is due to LFA-1/ICAM-1 interaction, and we suggest that this characteristic feature of AH66F cells may be related to the malignant properties.

Polymerase chain reaction of Borrelia burgdorferi flagellin gene in Shulman syndrome

A 49-year-old man presented a progressive swelling and induration of the skin resulting in flexion contracture. He had a history of two tick bites at the age of 17 and 47 years. Serum anti-Borrelia-burgdorferi antibody was positive; isolation of B. burgdorferi from the skin lesion was unsuccessful. He had eosinophilia (white blood cells 8,300/microlitre, 33% eosinophils) and hypergammaglobulinemia. The diagnosis of Shulman syndrome (eosinophilic fasciitis) from clinical and histological findings was established. A part of the flagellin gene of B. burgdorferi was detected in a skin biopsy sample by using the polymerase chain reaction method. To the best of our knowledge, this is the first report of detection of B.-burgdorferi-specific DNA from a skin sample of Shulman syndrome.

Inflammatory demyelinating polyradiculitis in a patient with acute disseminated encephalomyelitis (ADEM)

A patient with severe acute disseminated encephalomyelitis died 12 days after the first symptom. Necropsy showed widespread severe demyelination in the CNS and some foci of demyelination in the spinal roots. The lesions in the peripheral nervous system were characterised by myelin stripping and the presence of macrophages, being severest in the spinal nerve roots. Some axons were completely demyelinated, whereas the axons themselves were preserved. Pathologically established ongoing demyelination in both CNS and peripheral nervous systems raises the possibility of a shared pathological epitope.

Regulation of follicle-stimulating hormone receptor

The acquisition of follicle-stimulating hormone (FSH) receptors during folliculogenesis is believed to be a key event in follicle development. We have examined the effects of FSH and activin on FSH receptor mRNA in cultured rat granulosa cells. Treatment of granulosa cells with FSH resulted in transient suppression of the FSH receptor mRNA levels 2-6 h after treatment, with subsequent recovery at 24 h. We could not detect a similar effect on FSH receptor mRNA by 8-bromoadenosine 3,5-cyclic monophosphate, which continuously stimulated FSH receptor mRNA over a similar time course. On the other hand, stimulation of the protein kinase C (PKC) pathway with phorbol myristate acetate mimicked the time course of the effects of FSH on the levels of FSH receptor mRNA. Taken together, these results suggest that the cAMP cascade may increase the mRNA levels of FSH receptor and, at the same time, the other cascade, PKC, may decrease FSH receptor mRNA levels. To further investigate the role of activin in the regulation of granulosa cell function, we studied the effect of activin on FSH receptor mRNA levels. Compared to the control, treatment with activin (100 ng/ml) increased FSH receptor mRNA in a time-dependent manner with a maximum circa 4-fold increase at 24 h. Treatment of granulosa cells with activin (20-300 ng/ml) for 24 h increased FSH receptor mRNA in a dose-dependent manner to a maximum circa 4-fold increase at concentrations of 100-300 ng/ml. Although follistatin alone had no detectable effect on FSH receptor mRNA levels, combination of follistatin (0-200 ng/ml) with activin (100 ng/ml) caused a significant reduction in the levels of activin-induced FSH receptor mRNA in a dose-dependent manner.

Assessment of the metastatic ability of rat hepatoma cells in chick embryos by the polymerase-chain reaction

To elucidate the degree of malignancy or the host-killing ability of rat ascites hepatoma AH66F, AH66 and AH130, the chick embryo-polymerase chain reaction system was used to measure the metastasis of these hepatoma cells. When inoculated into the chorioallantoic membrane vein of 10-day fertilized chicken eggs, AH66F cells metastasized in the lung and liver in an inoculum size-dependent manner up to 10(6) cells, but AH66 and AH130 cells only a little even at 10(6) cells. The adhesion of AH66F cells, but not other hepatoma cells, to rat mesentery-derived mesothelial cells was inhibited by protein kinase C inhibitors NA-382 and H-7, but not by other protein kinase inhibitors, and the life-span of rats inoculated with AH66F cells was also prolonged by treatment with Na-382. AH66F cells, pretreated with protein kinase inhibitors were inoculated into the fertile eggs and micrometastasis was assayed. Metastasis of AH66F cells in the chick embryo was clearly decreased by treatment with NA-382. The chick embryo-polymerase chain reaction system is a sensitive method to measure the metastatic ability of mammalian tumor cells, and the high metastatic ability of AH66F cells is probably related to their adhesion to target cells mediated by the protein kinase C pathway.

Successful twenty-four-hour canine lung preservation with lazaroid U74500A

BACKGROUND

Lipid peroxidation is known to contribute to ischemia-reperfusion injury. U74500A is a 21-aminosteroid (lazaroid) that prevents lipid peroxidation without corticoid side effects. We examined the effect of U74500A on lung preservation using a canine orthotopic single left lung transplantation model.

METHODS

Twelve adult mongrel dogs underwent left lung allotransplantation. The lungs of the donor dogs were flushed with University of Wisconsin solution (50 ml/kg). Six donor dogs were pretreated with U74500A (5 mg/kg intravenously) before preservation (group L, n = 6), whereas those dogs without pretreatment served as controls (group C, n = 6). Allografts were stored in University of Wisconsin solution for 24 hours at 1 degrees C. Left single lung transplantations were performed by means of standard technique. Before reperfusion, recipients in group L received another dose of U74500A. Arterial blood gas analysis and hemodynamic measurements were made by occluding the right pulmonary artery to evaluate the transplanted left lung function at a inspired oxygen fraction of 1.0. Serum lipid peroxide level was measured after 2 hours of reperfusion.

RESULTS

Arterial oxygen tension, arterial carbon dioxide tension, and left pulmonary vascular resistance at 6 hours after reperfusion were significantly better in group L than in group C (arterial oxygen tension: 510 +/- 66 and 219 +/- 149 mm Hg; arterial carbon dioxide tension: 47 +/- 16 and 68 +/- 14 mm Hg; left pulmonary vascular resistance: 2412 +/- 826 and 3904 +/- 1251 dyn center dot sec/cm5, group L and group C, respectively). Serum lipid peroxide level was significantly lower in group L (0.25 +/- 0.24 nmol/ml) than in group C (0.92 +/- 0.53).

CONCLUSIONS

The administration of U74500A prevented lipid peroxidation and preserved pulmonary allograft function after 24 hours of ischemia.

Pulmonary function is diminished in older asymptomatic smokers and ex-smokers with low attenuation areas on high-resolution computed tomography

OBJECTIVES

The relation between pulmonary function and low attenuation areas (LAAs) on high-resolution computed tomography (HRCT) is not clear in subclinical pulmonary emphysema. Accordingly we examined pulmonary function and HRCT in asymptomatic community-based volunteers.

DESIGN

The existence of LAAs on CT was evaluated independently by three respiratory physicians who were blind to the pulmonary function test data and smoking histories of the subjects. The LAA grade was assessed by a visual scoring method from 0 to 5, and the individual LAA score and the values of pulmonary function tests were compared.

PARTICIPANTS

57 subjects aged from 32 to 82 years [mean 62 +/- (SD) 11] years were enrolled in the study.

RESULTS

LAAs were found in 20 of the 49 subjects who were current or ex-smokers but in none of the 8 who never smoked. LAAs observed were mostly less than 25% of the total areas of the lungs. Although all mean values were within normal limits, the forced expiratory volume in 1 s (%pred), maximal expiratory flow at 50% of forced vital capacity (%pred), diffusing capacity of the lungs for carbon monoxide (DLCO; %pred) and diffusing capacity for carbon monoxide per unit alveolar volume (DLCO/VA; %pred) were all significantly less in those with LAAs than in those without LAAs. There was also a significant tendency for DLCO %pred and DLCO/VA %pred to decrease as the LAA scores increased.

CONCLUSION

Those who have LAAs on CT have a small but significant deterioration in pulmonary function tests even if the LAAs observed are minimal or mild in degree. Longitudinal studies will be necessary to determine whether LAAs on CT identify the subjects who will develop airflow obstruction over time.

Role of rBAT gene products in cystinuria

To investigate whether rBAT gene products function as a crystine transporter component or as a transport activator, we microinjected several C-terminal deletion mutants of rBAT cRNA into Xenopus oocytes, and measured transport activity for arginine, leucine and cystine in the presence and absence of sodium. Wild type rBAT significantly stimulated the uptake of all 3 amino acids 10-20 fold compared to control mutants. On the other hand, no mutant, except a Δ511-685 mutant, stimulated the uptake of these amino acids. However, the Δ511-685 mutant significantly increased the uptake of arginine. In the presence of sodium, the Δ511-685 mutant also increased the uptake of leucine. The Δ511-685 mutant did not stimulate crystine uptake in the presence and absence of sodium. Furthermore, inhibition of L-arginine uptake by L-homoserine was seen only in the presence of sodium. These results suggest that mutant rBAT stimulates the endogenous amino acid transport system y+ in oocytes. Finally, rBAT gene products, as the primary cause of cystinuria, may function as activators of the amino acid transport system in renal brush border membrane.

Novel inhibitors for multidrug resistance: 1,3,5-triazacycloheptanes

1,3,5-Triazacycloheptanes were synthesized and examined for reversal of the multidrug resistance dependent on P-glycoprotein. Most of these compounds increased the intracellular uptake of vinblastine in multidrug-resistant mouse leukemia P388/ADR cells without influence upon the vinblastine accumulation in P388/S cells. The efficacy of 1,5-dibenzyl-1,3,5-triazacycloheptanes in increasing the vinblastine accumulation was in the order of 2,4-dithioxo (5) > 2-oxo-4-thioxo (4) approximately 4-(methylthio)-2-oxo (6) > 2,4-dioxo (2). The efficacy was further increased when the benzyl group was converted to a chlorobenzyl group. Among these compounds, 6c [1,5-bis(4-chlorobenzyl)-1,5,6,7-terahydro-4-(methylthio)-2H-1,3,5 - triazepin-2-one] potentiated the in vitro cell growth-inhibitory effect of vinblastine, adriamycin, and mitomycin C on P388/ADR cells and prolonged the life span of P388/ADR-bearing mice in combined therapy with vinblastine more than vinblastine alone.

The senescence of oat leaf segments is promoted under simulated microgravity condition on a three-dimensional clinostat

Plants have evolved on the earth, indicating the morphology, growth and development, and life cycle of plants are highly influenced by gravity as well as other environmental stimuli. Indeed, simulated microgravity on a clinostat or hypergravity on a centrifuge has recently been reported to change the growth and development of plants (Hoson et al. 1992, 1993, 1995, Rasmussen et al. 1994, Kasahara et al. 1995). Senescence is a final drastic phenomenon in life cycle of plants, which is characterized by the loss of total chlorophyll and protein, and/or the formation of the abscission (Osborne 1973, Thimann 1977, Addicott 1982). Many environmental stimuli as well as the qualitative and quantitative changes of plant hormones have been reported to affect plant senescence. Among those stimuli, light is the most important factor to regulate plant senescence (Leopold 1964). Dark condition promotes leaf senescence due to the decrease in endogenous level of cytokinin and/or the increase in that of abscisic acid or ethylene (Tetley and Thimann 1974, Gepstein and Thimann 1980). However, there are few reports concerning the effect of gravity on leaf senescence. Strenuous effort to learn leaf senescence under microgravity condition has been done using a three-dimensional (3-D) clinostat. In this paper, we report that simulated microgravity condition on a 3-D clinostat promoted the senescence of oat leaf segments in the dark. A possible mechanism of microgravity condition on promoting the senescence is also discussed.

[Non-invasive evaluation of pulmonary hemodynamics by pulsed Doppler echocardiography in patients with chronic obstructive pulmonary disease]

Pulsed doppler echocardiography is reported to be a reliable method for evaluating pulmonary hemodynamics in patients with cardiovascular diseases, but not with chronic obstructive pulmonary disease (COPD) because of the difficulty in obtaining an appropriate echo-window in such patients. We examined 23 patients with COPD by doppler echocardiography (Hewlett-Packard, HP77020CV) with a 2.5 MHz transducer via the subcostal approach in a supine position. The right side of the heart catheterization was performed simultaneously in sixteen of these patients. The remaining 7 patients received the same procedure within one week of the doppler echocardiography. Adequate ejection flow pattern from the right ventricle was obtained in all the patients. Significant negative linear relationships were found between pulmonary arterial pressure and acceleration time (r = -0.67) and ejection time (r = -0.52). These findings show that doppler echocardiography can be useful when evaluating pulmonary hemodynamics even in patients with COPD.