Inhibition of phospholipase D by a protein factor from bovine brain cytosol. Partial purification and characterization of the inhibition mechanism

A specific protein inhibitor of partially purified bovine brain phospholipase D (PLD) was identified from bovine brain cytosol. The PLD inhibitor has been enriched through several chromatographic steps and characterized with respect to size and mechanism of inhibition. The inhibitor showed an apparent molecular mass of 30 kDa by Superose 12 gel exclusion chromatography and inhibited PLD activity with an IC50 of 7 nM. The inhibitor had neither proteolytic activity nor phospholipid-hydrolyzing activity. Because phosphatidylinositol 4,5-bisphosphate (PIP2), which is included in substrate vesicles, is an essential cofactor for PLD, we examined whether the inhibition might be mediated by sequestration of PIP2. PIP2 hydrolysis by phospholipase C (PLC)-beta1 was not affected by the inhibitor and the inhibitor did not bind to substrate vesicles containing PIP2. In contrast, a PH domain derived from PLC-delta1, which could bind to PIP2, showed a nearly identical inhibition of both PLC-beta1 and PLD activities. Thus, the PLD inhibition by the inhibitor is due to the specific interaction with not PIP2 but PLD. The suppression of PLD activity by the inhibitor was largely eliminated by the addition of ADP-ribosylation factor (ARF) and GTPgammaS. We propose that the inhibitor plays a negative role in regulation of PLD activity by PIP2 and ARF.

Incremental threshold loading in patients with chronic obstructive pulmonary disease

The purpose of this research was to study the reproducibility of incremental threshold loading, a test of inspiratory muscle endurance, in patients with mild to severe chronic obstructive pulmonary disease. Twenty-seven patients completed four weekly visits. A significant difference was noted between the first visit and subsequent visits for the maximum absolute load that patients could tolerate, but no difference was noted in the load relative to inspiratory strength. Breathing pattern did not change significantly among visits to account for the differences in absolute load. Patients had a tendency to use rapid shallow breathing at the end of the test, suggesting that they approached the limits of their endurance and thus nearly fatigued their inspiratory muscles.

Uptake and exudation of phenolic compounds by wheat and antimicrobial components of the root exudate

In the course of our study, it was found that phenyl propenoic acid derivatives were readily taken up by wheat. Leaf leachate components were chosen for the feeding experiments and p-coumaric acid, ferulic acid and caffeic acid were found to be quickly taken up into the plants via the roots. The analytical study revealed that the exudate contained potent antimicrobial compounds together with amino acids and sugars. Besides the primary metabolites, 4-hydroxystyrene, 3-methoxy-4-hydroxystyrene and 3-methoxy-4-acetoxystyrene were identified as exudate components from wheat roots in sterile hydroponic culture. This indicates that these antimicrobial components may play a significant role in the defense system as allelochemicals for the rhizosphere.

Reliability and validity of the 12-minute distance walk in patients with chronic obstructive pulmonary disease

Validity and test-retest liability of the 12-minute distance (12MD) walk, a measure of functional status, were examined in patients with chronic obstructive pulmonary disease. Four tests were administered at weekly intervals. Performance increased (p < .01) over the first three tests. Test-retest reliability was r34 = .98 (df = 46) for tests 3 and 4. The 12MD walk correlated with the Sickness Impact Profile, Physical Dimension (r = -.45); forced expiratory volume in 1 second % predicted ( r = .40); maximal inspiratory pressure (PImax) (r = .52); and exercise-related breathlessness (r = -.49). Exercise-related breathlessness and PImax accounted for 42% of the variance. The validity and reliability of the 12MD walk were supported.

Identification of the DNA damage-responsive elements of the rhp51+ gene, a recA and RAD51 homolog from the fission yeast Schizosaccharomyces pombe

The Schizosaccharomyces pombe rhp51+ gene encodes a recombinational repair protein that shares significant sequence identities with the bacterial RecA and the Saccharomyces cerevisiae RAD51 protein. Levels of rhp51+ mRNA increase following several types of DNA damage or inhibition of DNA synthesis. An rhp51::ura4 fusion gene was used to identify the cis-acting promoter elements involved in regulating rhp51+ expression in response to DNA damage. Two elements, designated DRE1 and DRE2 (for damage-responsive element), match a decamer consensus URS (upstream repressing sequence) found in the promoters of many other DNA repair and metabolism genes from S. cerevisiae. However, our results show that DRE1 and DRE2 each function as a UAS (upstream activating sequence) rather than a URS and are also required for DNA-damage inducibility of the gene. A 20-bp fragment located downstream of both DRE1 and DRE2 is responsible for URS function. The DRE1 and DRE2 elements cross-competed for binding to two proteins of 45 and 59 kDa. DNase I footprint analysis suggests that DRE1 and DRE2 bind to the same DNA-binding proteins. These results suggest that the DRE-binding proteins may play an important role in the DNA-damage inducibility of rhp51+ expression.

Mechanism of menadione-induced cytotoxicity in rat platelets

The elevation of intracellular Ca2+ in various tissue through oxidative stress induced by menadione has been well documented. Increase of Ca2+ level in platelets results in aggregation of platelets. To test the hypothesis that menadione-induced Ca2+ elevations can play a role in platelet aggregation, we have studied the effect of menadione on aggregation of platelets isolated from female rats. Treatment with menadione to platelet-rich plasma (PRP), which proved to be an adequate system, appeared to induce dose-dependent platelet aggregations up to 60%, as determined by aggregometry. However, exposure of PRP to menadione led to slow reduction of platelet cell number coincident with a loss of viability, as measured by lactate dehydrogenase leakage, suggesting that menadione might induce cell lysis rather than aggregation of platelets. Light microscopy confirmed that menadione reduced the number of platelets and failed to show aggregates of platelets. To elucidate the mechanism of this cytotoxicity, menadione-induced oxygen consumption was studied in intact rat platelets. Incubation of platelets with menadione resulted in rapid dose-dependent increases of oxygen consumption, which were not inhibited by indomethacin and nordihydroguaiaretic acid, suggesting that menadione did not affect the cyclooxygenase and lipoxygenase pathways in platelets. Oxygen consumption, as well as cytotoxicity by menadione, was unaffected by addition of dicoumarol, which is a quinone reductase (QR) inhibitor. Consistent with these findings, no activity of QR was detected in any subcellular fractions of platelets. Oxygen consumption by several subcellular platelet fractions treated with menadione was examined in the presence of NADPH or NADH. Additions of NADPH or NADH to microsomal fractions or a 9000 g pellet (which contains plasma membranes) led to 2-fold to 18-fold elevations in platelets may contribute to the oxidative damage associated with menadione-induced oxygen consumption, respectively. These results suggest that NADPH and/or NADH-dependent enzyme systems in menadione-induced cytotoxicity.

Respiratory muscle strength in older adults

Gender-related effects and two measures of muscularity, handgrip strength and fat-free mass (FFM), were examined to determine their relationship to respiratory muscle strength. Subjects were 101 healthy older adults. In 75 subjects, the magnitude of learning effect was examined over four weekly sessions. Maximal inspiratory pressure (PImax) was lower with increasing age in women, and maximal expiratory pressure (PEmax) was lower with increasing age in both genders. The PEmax correlated with handgrip strength and FFM in men only. Performance of PImax plateaued by the third visit in both men and women. Performance of PEmax plateaued by the third measure in women and was unchanged across four measurements for men.

Post-exercise response of ventricular ejection fraction after total repair of congenital heart disease with left to right shunt

A radioisotope first pass study was done on patients over a period of 1 to 15 years (average 4.6 years) after repair for ventricular septal defect or arterial septal defect with a left to right shunt. The age of the patients ranged from 6 to 32 years (average 14.2 year) at the time of the study. The total work of exercise and the right and left ventricular ejection fraction(EF) were evaluated at rest and after exercise. The results were compared with the preoperative hemodynamic findings and with the age of patient at the time of the operation. 1) When the total work of exercise was divided with the maximal exercise capacity of the normal individual corresponding to the patients' height and body surface area (the percentage of total work), it were very low with the average of 40% of normal. There was no sexual difference, but the percentage of total work of exercise had significant correlation with the patients' age at the time of operation (r = -0.52, p < 0.01) and post-exercise left ventricular ejection fraction (LVEF)(r = -0.39, p < 0.05). 2) LVEF at rest had some correlation with the preoperative mean pulmonary arterial pressure (r = -0.29, p = 0.05), but showed no relationship with Qp/Qs or Rp/Rs ratios. The right ventricular ejection fraction (RVEF) at rest had no relations with the preoperative hemodynamic findings with maximal workload. 3) The post-exercise RVEF showed linear correlation with the preoperative Rp/Rs ratio (r = -0.49, p < 0.005), and mean pulmonary arterial pressure (r = -0.37, p < 0.05). The post-exercise LVEF had no significant correlation with any preoperative hemodynamic factors. 4) When greater than 5% increase in ventricular EF after exercise is considered normal, the group with the normal right and left ventricular responses (n = 11) showed normal preoperative Rp/Rs ratio (7.6 +/- 4.1). In the group with normal left, but abnormal right ventricular response (n = 9) and the group with abnormal biventricular response (n = 11), both demonstrated incremental increase in Rp/Rs ratio (20.1 +/- 11.3, 26.3 +/- 19.8 respectively). Normal right, but abnormal left ventricular reaction (n = 2) was noted in patients with residual aortic valvular insufficiency and residual ventricular septal defect. In conclusion, post-operative ventricular response was much more sensitive and informative than that of ventricular function at rest and to detect subclinical cardiac dysfunction. Post-exercise RVEF was closely correlated with preoperative pulmonary vascular hemodynamics, while post-exercise LVEF seemed to be a major determinant of working capacity after repair.

MR imaging of tuberculous arthritis: clinical and experimental studies

Signal-intensity characteristics of magnetic resonance (MR) images were assessed in five patients and in 10 rabbits with tuberculous arthritis. MR imaging findings were compared with histologic findings in the animal study. In both of clinical and experimental cases, tuberculous lesions showed both intermediate and high signal intensity on T2-weighted images, while they showed heterogeneously intermediate signal intensity on T1-weighted images. As T2-weighted images were compared with pathologic specimens, intermediate signal intensity corresponded to caseous necrosis, whereas high signal intensity related to granulomas or effusion. Postcontrast T1-weighted images showed enhancement at the peripheries rather than the centers of tuberculous lesions. These results indicate that tuberculous arthritis should be included in the differential diagnosis when intra-articular lesions with low or intermediate signal intensity are found on T2-weighted images.

Effect of glutathione depletion on haemoglobin and membrane integrity of red blood cells of rats

The effects of streptozocin (streptozotocin) and water-soluble menadione (menadione bisulphite, sodium salt) on the haemoglobin content and membrane integrity of red blood cells were investigated. Both menadione bisulphite and streptozocin significantly depleted glutathione but menadione bisulphite was much more effective in reducing glutathione than was streptozocin. Menadione bisulphite, at concentrations above 0.1 mM, caused substantial conversion of oxygenated haemoglobin into methaemoglobin while streptozocin did not alter the haemoglobin content of the red blood cells at concentrations of up to 100 mM. Both agents demonstrated only a modest ability to haemolyse the red blood cells, even at concentrations up to 300 mM. These results suggest that depletion of glutathione by menadione causes the conversion of oxyhaemoglobin to methaemoglobin. In contrast, streptozocin-induced glutathione depletion does not seem to be well correlated with alterations in haemoglobin content.

Bronchiolitis obliterans in children with Stevens-Johnson syndrome: follow-up with high resolution CT

About one third of children with Stevens-Johnson syndrome have pulmonary involvement. As a consequence of airway epithelial injury, bronchiolitis obliterans can occur in these patients. Two cases of Stevens-Johnson syndrome-associated bronchiolitis obliterans in children were diagnosed and followed by high resolution CT without open lung biopsy. Serial changes of high resolution CT features of bronchiolitis obliterans are discussed and the literature is reviewed.

Homogeneous assays for riboflavin mediated by the interaction between enzyme-biotin and avidin-riboflavin conjugates

Homogeneous-type enzyme-linked competitive binding assays utilizing the synthetic enzyme-biotin and avidin-riboflavin conjugates are developed for the detection of riboflavin as well as its binder protein. The activity of the enzyme-biotin conjugate is inhibited in the presence of the avidin-riboflavin conjugate, and the observed inhibition is reversed in an amount dependent on the concentration of riboflavin binding protein (RBP) added. Upon additions of free riboflavin to the mixture, activity is reinhibited in an amount proportional to the riboflavin concentration. Three different enzymes are examined as the labels: glucose-6-phosphate dehydrogenase, adenosine deaminase, and alkaline phosphatase. The catalytic activity of these enzymes, when conjugated with biotin, is shown to be inhibited to a significant degree (> 90%) by the binding of the avidin-riboflavin conjugate, and reversed upon additions of RBP.

Evidences for possible involvement of Rhp51 protein in mitotic events including chromosome segregation

To understand the role of the Rhp51 protein in Schizosaccharomyces pombe, we examined the phenotypes of the null mutant for the rhp51+ gene. Unlike Saccharomyces cerevisiae rad51 mutants, S. pombe rhp51 mutants (rhp51delta cells) displayed slow growth and heterogeneity in cell size, indicating perturbation of the cell cycle. Furthermore, many aberrant nuclear structures found in 4',6'-diamidino-2-phenylindole (DAPI)-stained rhp51delta cells and the caffeine hypersensitivity of the mutant cells suggested an involvement of the Rhp51 protein in normal chromosome segregation. These data suggested that the Rhp51 proteins were required for normal cell growth as well as a DNA repair pathway. Moreover, rhp51delta mutants showed a considerable sensitivity to ultraviolet (UV) light-irradiation as well as methyl methanesulfonate (MMS) treatment, indicating that the Rhp51 proteins are involved in both the active excision mechanism of UV-induced DNA damage and recombinational repair in S. pombe. Taken together, we suggest that the role(s) of the Rhp51 protein in S. pombe may be different from those of Rad51 in S. cerevisiae.

A simple and efficient method for the isolation of total RNA from the fission yeast Schizosaccharomyces pombe

A simple and efficient procedure was described for the isolation of total RNA from the fission yeast Schizosaccharomyces pombe. The present study demonstrated that the quality and the quantity of S. pombe RNA were increased by substituting phenol/chloroform mixture for phenol as a deproteinizing agent in the first vortexing step and using an ice bath instead of a dry ice-ethanol bath in the freezing step. Additionally, this protocol had the advantage of extracting total RNA without any degradation of S. pombe cells. Furthermore, the high amounts and quality of RNA extracted by this modified procedure enabled us to perform some experiments such as Northern blot, S1 mapping, primer extension, and reverse transcriptase reaction-polymerase chain reaction (RT-PCR) without further RNA purification. We suggest that this procedure is very useful to analyse primary structures and steady-state levels of RNA from S. pombe.

Characterization of SFP2, a putative sulfate permease gene of Saccharomyces cerevisiae

The SFP2 gene of Saccharomyces cerevisiae has been characterized. The deduced amino acid sequence contained twelve highly hydrophobic domains and showed 50, 47, 44 and 48% homologies to Neurospora crassa sulfate permease II (CYS14), soybean GMAK170 nodulin, human colon mucosa protein (DRA) and a putative open reading frame (ORF) downstream of Escherichia coli prs (phosphoribosyl pyrophosphatate synthetase) gene, respectively, in the aligned regions. Cells lacking SFP2 were viable and displayed no obvious decrease in their growth rate. Southern blot analysis revealed that SFP2 exists as a single copy in haploid genome. Northern blot analysis showed that SFP2 produced a 2.8-kb transcript which was highly expressed under sulfur derepressing condition. SFP2 mRNA was found to turn over with a half-life of approximately 15 min, which may contribute to the regulation of sulfate permease function, and reached its maximal level in about 22 h after depression.

A case of rectal cancer with sternal metastasis as initial presentation

Colorectal cancer with bone metastasis as initial manifestation is a very rare event. We have reported a case of rectal cancer presenting with sternal metastasis. A 30 year-old man was evaluated due to pain in the sternal area with a bulging mass. History and physical examination did not suggest any specific disease. A radionuclide bone scan revealed increased uptake in the sternal area, right 6th rib, and sacrum. Microscopic examination of a biopsy specimen from the sternum showed metastatic adenocarcinoma. A barium enema and CT scan of the pelvis suggested carcinoma of the upper rectum. Adenocarcinoma of the rectosigmoid junction area was demonstrated by colonoscopic examination with biopsy. He received palliative transverse colostomy for obstruction without further treatment.

The efficacy of cyclosporine A in adult nephrotic syndrome with minimal change disease and focal-segmental glomerulosclerosis: a multicenter study in Korea

A multicenter prospective study conducted in four university hospitals in Korea investigated the efficacy and tolerance of cyclosporine A (CyA, Sandimmun) in 30 patients with adult nephrotic syndrome [25 patients with minimal change disease (MCD) and 5 with focal-segmental glomerulosclerosis (FSGS)]. After a 6-week washout period, CyA 5 mg/kg/day and prednisolone 10 mg/day were administered for up to 8 months, depending on responses to CyA. The rate of relapse after withdrawal of CyA was assessed up to 10 months. Of the 30 patients enrolled, 3 withdrew prematurely due to adverse events. Of the 27 patients who completed the study, 22 had MCD and 5 had FSGS. The prior steroid responses of these patients were 19 steroid-dependent (SD), 4 frequent-relapser (FR) and 4 steroid-resistant (SR) type. High rates of complete remission were obtained after CyA treatment in both MCD and FSGS patients, 86.4% (19/22) and 80% (4/5) respectively. Previous steroid responses did not affect the response to CyA; complete remission was obtained in 84.2% (16/19) of SD patients and in 75% (3/4) of SR patients. The mean (+/- SEM) duration of CyA treatment to attain complete remission in SD and SR patients was 3.8 (+/- 0.6) weeks and 10.7 (+/- 2.7) weeks, respectively (not significantly different). Tapering or withdrawal of CyA was followed by release of nephrotic syndrome in many patients, and the cumulative relapse rates at month 10 were 68.4% (13/19) in MCD patients and 50% (2/4) in FSGS patients. When considered according to prior steroid responses, the relapse rate was 73.3% (11/15) in SD patients and 50% (2/4) in SR patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Staurosporine induces de novo synthesis of prostaglandin H synthase-2 in rat alveolar macrophages

This study was initiated to investigate the possible involvement of prostaglandin H synthase in the staurosporine-induced prostaglandin production. The time course of prostaglandin H synthase activity in macrophages treated with staurosporine (20 nM) showed that the maximum activity was reached in 20 h. The stimulatory effect of staurosporine on thromboxane B2 production was maximum at 50 nM staurosporine and this effect was reversed at higher concentrations. Immunoprecipitation of 35S-labeled enzyme using an antibody specific for prostaglandin H synthase-2 paralleled the changes in enzyme activity. These results indicate that increased de novo synthesis of prostaglandin H synthase-2 is largely, if not solely, responsible for staurosporine-stimulated prostaglandin production in macrophages.

Augmentation of vascular endothelial barrier function by heparin and low molecular weight heparin

Glycosaminoglycans (GAGs) are an important component of endothelial barrier function. Early passage human umbilical vein endothelial cells were grown to confluence on transparent micropore filters and barrier function assessed as transendothelial electrical resistance (TEER) and permeability to albumin and sucrose. Unfractionated heparin and the LMW heparin Clexane decreased endothelial permeability to both sucrose and albumin and increased TEER. Chondroitin 6-sulphate also augmented barrier function, but other GAGs had no effect. Interleukin-1 increased permeability to albumin and sucrose and decreased TEER. Although heparin attenuated the effect of IL-1 on TEER and sucrose permeability, it could not restore the barrier to albumin transfer. Denuded endothelial matrix presented a negligible barrier, which was not enhanced by heparin. When sulphation of endogenous GAGs was inhibited by chlorate, barrier function was compromised and was not restored by exogenous heparin. Thus heparin enhances the barrier function of resting endothelium, but cannot completely overcome the increased permeability resulting from exposure to IL-1 or substitute for endogenous GAGs.

Bone marrow findings before and after treatment with recombinant human erythropoietin in chronic hemodialyzed patients

The stimulating effect of rHuEPO on erythropoiesis has been shown in several studies, using bone marrow cell culture or animal models. To investigate the effect of rHuEPO on bone marrow findings in vivo, we studied the bone marrow cellularity, the myeloid: erythroid (M:E) ratio, an estimate of the number of megakaryocytes, any cytomorphologic or maturation abnormalities, and an estimate of the storage iron before and after 3 months of treatment with rHuEPO in 10 chronic hemodialyzed patients. Nine patients showed a slight or moderate decrease of erythropoiesis in bone marrow in comparison to normal bone marrow before rHuEPO treatment. The bone marrow cellularity was a mean of 28.5% and decreased in 8 out of 10 patients compared to normal values. However, megakaryopoiesis and granulopoiesis were normal. Three months of treatment with rHuEPO had increased erythropoiesis in all 10 patients, including one patient whose bone marrow proved to be normal erythropoiesis on baseline examination. The M:E ratio was significantly decreased from 4.0 +/- 1.2:1 to 2.4 +/- 1.1:1 (p < 0.005). The bone marrow cellularity was also increased in 9 patients, except in 1 patient whose specimen was inadequate for diagnosis, after 3 months of treatment with rHuEPO. On baseline examination of bone marrow, iron staining was undetectable in one, low in one, normal in 2 and high in 5 sections. According to grading, iron staining had decreased from 3.1 +/- 1.7 to 2.1 +/- 0.9 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Mandibular reconstruction with free vascularized fibular flap

Although various sources of vascularized bone/composite tissue have been used for mandibular reconstruction, the vascularized fibular flap has been reported to have many advantages over the others and to be the most suitable for bridging a long-span mandibular defect. In this paper, positive experience of 14 consecutive cases in which a free vascularized fibular graft with or without a skin paddle has been used to reconstruct a long mandibular defect is reported. Half of the cases were primarily reconstructed, the rest secondarily. The average length of the fibula graft harvested was 16.7 cm, with a range of 12 to 22 cm. The number of wedge osteotomies ranged from 0 to 4, with an average of 1.67. In ten flaps, a peroneal skin paddle was included. The donor wound was typically closed directly, except in three cases, where a skin graft was used. Vein grafts were performed in five cases to lengthen the pedicle. In two cases, the skin partially necrosed. All scintigrams except one showed good bone viability. But there was no total flap failure. Postoperative facial appearances were fair to excellent, with mouth opening ranging from 21 to 50 mm. Although unusual serious donor wound rupture was experienced in one case, in general the donor site complications were minimal.