Clathrin-dependent and -independent internalization of plasma membrane sphingolipids initiates two Golgi targeting pathways

Sphingolipids (SLs) are plasma membrane constituents in eukaryotic cells which play important roles in a wide variety of cellular functions. However, little is known about the mechanisms of their internalization from the plasma membrane or subsequent intracellular targeting. We have begun to study these issues in human skin fibroblasts using fluorescent SL analogues. Using selective endocytic inhibitors and dominant negative constructs of dynamin and epidermal growth factor receptor pathway substrate clone 15, we found that analogues of lactosylceramide and globoside were internalized almost exclusively by a clathrin-independent ("caveolar-like") mechanism, whereas an analogue of sphingomyelin was taken up approximately equally by clathrin-dependent and -independent pathways. We also showed that the Golgi targeting of SL analogues internalized via the caveolar-like pathway was selectively perturbed by elevated intracellular cholesterol, demonstrating the existence of two discrete Golgi targeting pathways. Studies using SL-binding toxins internalized via clathrin-dependent or -independent mechanisms confirmed that endogenous SLs follow the same two pathways. These findings (a) provide a direct demonstration of differential SLs sorting into early endosomes in living cells, (b) provide a "vital marker" for endosomes derived from caveolar-like endocytosis, and (c) identify two independent pathways for lipid transport from the plasma membrane to the Golgi apparatus in human skin fibroblasts.

[Plasma levels of soluble fibrin in patients with disseminated intravascular coagulation]

Soluble fibrin(SF) is formed in the early-activated state of blood coagulation and quantitative measurement of SF shows high potential as a parameter for the diagnosis of suspected disseminated intravascular coagulation(DIC). The aim of the present study is to evaluate the usefulness of a newly developed SF test utilizing SF specific monoclonal antibody(F405). Among hemopoietic and non-hemopoietic tumor patients, 249 patients with suspected DIC were collected. The SF level showed a good correlation with the DIC score and the SF levels in DIC patients were significantly higher than those in s-DIC and pre-DIC patients. Receiver operating characteristic(ROC) analysis also showed that the specificity and sensitivity of the SF assay were higher than those of thrombin-antithrombin complex(TAT). In conclusion, these results indicate that the SF assay is a highly precise method for the diagnosis and screening of DIC stages.

Plasma levels of total plasminogen activator inhibitor-I (PAI-I) and tPA/PAI-1 complex in patients with disseminated intravascular coagulation and thrombotic thrombocytopenic purpura

In this study, we examined changes in the plasma levels of total plasminogen activator inhibitor-I (PAI-I) and tissue-type plasminogen activator (tPA)/PAI-I complex in patients with disseminated intravascular coagulation (DIC) and in those with thrombotic thrombocytopenic purpura (TTP) to investigate the fibrinolytic function and its relation to organ failure. The plasma levels of total PAI-1 and tPA/PAI-I complex were significantly higher in patients with DIC, pre-DIC, and TTP than in those with non-DIC. The plasma levels of thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex (PPIC), D-dimer, thrombomodulin (TM), total PAI-I, and tPA/PAI-I complex were significantly higher in patients with organ failure than in those without organ failure. The plasma levels of total PAI-I and tPA/PAI-I complex were markedly increased in patients with acute leukemia. The plasma levels of total PAI-I, but not those of tPA/PAI-I complex, were significantly increased in patients with sepsis or with solid cancer. In all cases, total PAI-I or tPA/PAI-I complex was not significantly correlated with any hemostatic marker. Measurement of total PAI-I and tPA/PAI-I complex may be useful in the diagnosis of DIC.

Hypercalcemia after High-Dose Chemoradiotherapy for Refractory Multiple Myeloma; Subject Heading

A 43-year-old man with refractory myeloma underwent allogeneic bone marrow transplantation from his HLA-matched sibling. He was conditioned with TBI (12 Gy) followed by melphalan (140 mg/m(2) ). Immediately after conditioning was initiated, he began complaining of severe lumbago, and the level of serum calcium rose from 2.25 to 3.34 mmol / l. However, the biochemical markers for tumor-lysis syndrome such as potassium, uric acid, and lactic dehydrogenase remained unchanged. Hydration with saline and pamidronate were started, but he developed acute renal failure requiring hemodialysis for 3 weeks. His plasma parathyroid hormonerelated protein (PTHrP)-NH2-terminal (3.9 pmol/l) and serum PTHrP-C-terminal (125.0 pmol / l) levels markedly increased immediately after conditioning. These results suggested that the increased release of PTHrP from myeloma cells, which resulted from destruction of myeloma cells by conditioning, was the primary contributes to the occurrence of hypercalcemia. We should be aware of the occurrence of hypercalcemia when high-dose therapy is to be given to patients with refractory myeloma.

Immunohistochemical characterisation of a case of insular thyroid carcinoma

A case of insular thyroid carcinoma arising in the right lobe of a 54-year-old male is reported. The tumour exhibited an invasive growth pattern with regional lymph node metastasis. Microscopically, the tumour was characterised by well-defined solid nests like insulae, including mature follicles containing colloid and immature follicles without colloid. Immunohistochemically, tumour cells in follicular areas predominantly exhibited immunopositivity to antithyroglobulin antibody. On the other hand, diffuse immunoreactions with anti-neuron-specific enolase (NSE), S-100 protein and Leu-7 were detected mainly in the tumour cells of solid areas. In addition, clear cytoplasmic immunoreactivity with anti-myelin basic protein (MBP) antibody was exhibited in a number of tumour cells. Ultrastructurally, many tumour cells possessed dense vacuoles, apparently containing colloid material, but intracytoplasmic neurosecretory granules were absent. The histopathological and ultrastructural characteristics of the tumour as well as its anti-thyroglobulin antibody immunoreactivity support the classical hypothesis that this neoplasm is a variant of poorly differentiated thyroid carcinoma. The positive immunohistochemical reactions for NSE, S-100, MBP and Leu-7 raise the possibility of aberrant differentiation, for example neural.

Successful treatment of dry eye in two patients with chronic graft-versus-host disease with systemic administration of FK506 and corticosteroids

PURPOSE

We present two cases of severe dry eye in patients with chronic graft-versus-host disease (CGVHD) after hematopoietic stem cell transplantation (SCT) who were successfully treated by the systemic administration of FK506 and corticosteroids.

METHODS AND RESULTS

A 29-year-old man with chronic myelogenous leukemia underwent SCT. Oral and lung CGVHD developed on approximately day 130, and dry eye associated with CGVHD was diagnosed on day 168. The patient began receiving cyclosporin A (150 mg/d) for the treatment of oral and lung CGVHD. Treatment with prednisolone (1 mg/kg/d) began on approximately day 300. Oral and lung GVHD improved slightly, but worsened again although systemic administration of cyclosporin A and prednisolone were continued. Cyclosporin A was discontinued, and systemic administration of FK506 was started on day 376. Forty-four days later, marked improvement in the ocular surface and other organs was observed. However, the dry eye worsened while tapering FK506, with no flare of other affected organs. A 43-year-old woman with myelodysplastic syndrome underwent SCT. She received FK506 for prophylaxis of CGVHD. She had mild dry eye before SCT. Oral and intestinal CGVHD developed, and the dry eye worsened significantly on approximately day 150 while tapering FK506. Treatment with prednisolone (1 mg/kg/d) began, and the dose of FK506 was increased. By day 240, the symptoms of dry eye and the findings of the ocular surface markedly improved, and CGVHD in other organs was completely resolved. However, the improvement in the dry eye was lost when FK506 was tapered for the second time.

CONCLUSION

Systemic administration of FK506 with corticosteroids is an effective treatment of severe dry eye in patients with CGVHD, but long-term administration may be required to achieve a lasting response. These cases also suggest that further investigation into the use of topical FK506 and prednisolone as a maintenance therapy should be pursued.

Isolation and structures of hedaols A, B, and C, new bisnorditerpenes from a Japanese brown alga

New bisnorditerpenes, hedaols A (1), B (2), and C (3), were isolated from the Japanese brown alga Sargassum sp. Their structures were determined by spectroscopic analysis. The absolute stereocenter of 1 was determined by the modified Mosher's method. Hedaols showed low cytotoxicity against P388 cells.

Adult T-cell leukemia with hypercalcemia-induced metastatic calcification in the lungs due to production of parathyroid hormone-related protein

A 60-year-old man was diagnosed as adult T-cell leukemia with severe hypercalcemia because of production of parathyroid hormone-related protein. After admission, the patient had respiratory insufficiency with an infiltrative shadow in his lungs suggestive of pneumonia. However, neither improvement in respiratory function nor disappearance of the abnormal chest shadow was observed with administration of various antibiotics. An autopsy demonstrated the chest shadow had been caused by metastatic calcification associated with hypercalcemia due to production of parathyroid hormone-related protein. The possibility of metastatic calcification should be considered in patients with adult T-cell leukemia and hypercalcemia who have an abnormal chest shadow.

Novel role of phosphatidylinositol 3-kinase in CD28-mediated costimulation

Ligation of the CD28 surface receptor provides a major costimulatory signal for full scale T cell activation. Despite extensive studies, the intracellular signaling pathways delivered by CD28 ligation are not fully understood. A particularly controversial matter is the role of phosphatidylinositol 3-kinase (PI3K) in CD28-mediated costimulation. It is known that the binding site for PI3K and Grb-2 lies nested within the YMNM motif of the CD28 cytoplasmic domain. To elucidate the role of PI3K during CD28-mediated interleukin-2 (IL-2) production, CD28 YMNM point and deletion mutants were expressed in Jurkat cells. We then measured IL-2 promoter activation after CD28 ligation. Our results showed that the Y189F mutant, which disrupts binding by PI3K, and the YMNM deletion mutant both demonstrated reduced but significant activity for IL-2 promoter activation. In contrast, the N191A mutant, which retains PI3K binding ability, resulted in a complete abrogation of activity, suggesting that PI3K mediates a negative effect upon transcriptional activation of the IL-2 gene. Consistent with this idea, we found that the addition of a PI3K pharmacological inhibitor augmented IL-2 promoter activity, whereas coexpression of a constitutively active form of PI3K reduced this activity. Taken together, these data indicate that PI3K, when associated with the YMNM motif, may act as a negative mediator in CD28-mediated IL-2 gene transcription.

Expression of E-cadherin and catenins on testis tumor

E-cadherin (ECD) is a homophilic Ca(2+)-dependent adhesion molecule associated with cell-to-cell interactions and normal growth. Recent reports have suggested that decrease or loss of ECD facilitates tumor progression and/or metastasis. ECD functions in a complex called an adherens junction, which includes several other proteins including alpha- and beta-catenin. In the present study, fresh-frozen sections from 32 testis cancers, 16 seminomas and 16 non-seminomatous germ cell tumors (NSGCT), were examined immunohistochemically. E-cadherin was not expressed on normal germ cells, but expressed on 3 (18.8%) of 16 seminomas and 10 (62.5%) of 16 NSGCTs, mainly on the epithelial component of teratoma cells. alpha-Catenin was detected on 0 (0%) of 13 seminomas and 4 (25%) of 16 NSGCTs. beta-Catenin was detected on 10 (71.4%) of 14 seminomas and 13 (81.2%) of 16 NSGCTs. ECD was detected significantly more frequently on NSGCTs than on seminomas. Immunoblot analysis confirmed the expression of ECD and beta-catenin in NSGCTs. Expression of ECD and catenins may reflect the degree of differentiation and provide some information on the character of the tumor.

Neurovirulence in mice of soluble receptor-resistant (srr) mutants of mouse hepatitis virus: intensive apoptosis caused by less virulent srr mutant

Three soluble receptor-resistant (srr) mutants, srr7, srr11 and srr18, derived from a highly neurotropic mouse hepatitis virus (MHV) JHMV have a single amino acid mutation in the spike (S) protein. We examined using ICR mice whether the amino acids mutated in the mutants were involved in the neurovirulence. Srr7 showed apparently reduced neurovirulence relative to the wild-type (wt) JHMV in terms of the LD50 and survival time, while the others showed slightly reduced virulence. In the brain and spinal cord, the growth of srr7 was more than 2 log10 lower than that of the wt virus. Histopathologically, no significant difference was revealed between wt and srr7-infected mice on day 2 postinoculation (p.i.), with only scant inflammation and a minimum degree of neuropathological changes. The major difference was that apoptotic cells were frequently encountered in the srr7-infected mouse brain, but not in wt-infected mice on day 2 p.i. However, there was no difference between these viruses in the potential to induce apoptosis in cultured cells. The apoptosis in the brain did not appear to result from the direct viral attack, since apoptotic cells were found in the lesion where viral antigens were barely detected. The present study suggests that the amino acids mutated in the S protein of srr mutants, especially the amino acid at position 1114 mutated in srr7, influence the neurovirulence in mice.

Increased plasma thrombomodulin as a vascular endothelial cell marker in patients with thrombotic thrombocytopenic purpura and hemolytic uremic syndrome

Several hemostatic and vascular endothelial cell markers were measured in 39 patients with thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) and in 20 healthy volunteers to examine the relationship between the occurrence of hemostatic abnormality or vascular endothelial cell injury and patient outcome. The plasma levels of von Willebrand factor, tissue plasminogen activator (TPA), plasminogen activator inhibitor (PAI-1), and the TPA-PAI-1 complex were significantly increased in TTP/HUS patients; however, the levels of these markers were not significantly different between TTP/HUS patients who survived and those who died, suggesting that these markers might not be directly related to outcome. The plasma levels of soluble granule membrane protein (GMP)-140 were significantly higher in TTP/HUS patients than in healthy volunteers, suggesting that platelets and vascular endothelial cells are activated or injured in TTP/HUS. There was no significant difference in GMP-140 levels between TTP/HUS patients with good and poor prognoses; this may be owing to the release of GMP-140 from platelets. The plasma thrombomodulin (TM) levels in TTP/HUS patients were significantly higher than in healthy volunteers; the plasma TM levels were significantly higher in patients who died than in patients who survived. These findings showed that TM levels reflect the outcome and that the outcome of TTP/HUS depends on the presence vascular endothelial cell injury. The plasma protein C and antithrombin levels were markedly reduced in TTP/HUS patients who died compared with those who survived. These findings suggest that reduced plasma antithrombin and protein C may be useful markers of systemic vascular endothelial injury. In conclusion, the results of this study showed that the outcome of TTP/HUS is related to vascular endothelial cell injury and that plasma TM, antithrombin, and protein C levels may be useful markers of systemic vascular endothelial cell injury.

[A case of moyamoya disease presenting with geographic mislocation, person misidentification and fantastic confabulation]

A 52-year-old woman presented with geographical mislocation (misidentification for place), person misidentification and fantastic confabulation as a result of cerebral infarction. Head MRI demonstrated a focal lesion in the right frontal lobe. Cerebral angiogram demonstrated occlusion in the circle of Willis with moyamoya vessels. The neuropsychological examination revealed memory impairment and frontal lobe dysfunction. The patient's misidentification for place and person as well as confabulation lasted for 1.5 months since admission, then gradually disappeared. We speculate that there existed a common mechanism for these three symptoms; i.e., misidentification and confabulation were based upon the impaired interpretation of the small events and partial objects in the surrounding circumstances, which might interfere with the appropriate integration and judgments of the outside information in general. The impaired monitoring and frontal dysfunction caused by the right frontal lesion appeared to be responsible for causing her deficits.

[Idiopathic hyperammonemia following allogeneic bone marrow transplantation for refractory lymphoma]

Idiopathic hyperammonemia (IHA) is a rare but serious complication of stem cell transplantation. We report a patient with immunoblastic lymphoadenopathy-like T-cell lymphoma who developed IHA 10 days after allogeneic bone marrow transplantation from an HLA-matched unrelated donor. Despite intensive supportive care, the patient died due to this metabolic disorder two days later. Being mindful of the possibility of IHA in patients who develop confusion and respiratory alkalosis soon after stem cell transplantation would allow earlier treatment and might improve the chance of survival.

Increased plasma levels of tissue factor pathway inhibitor-activated factor X complex in patients with disseminated intravascular coagulation

Plasma levels of tissue factor pathway inhibitor (TFPI)-activated factor Xa (FXa) complex were measured in patients with disseminated intravascular coagulation (DIC), pre-DIC, and DIC. Plasma levels of plasmin-plasmin inhibitor complex (PPIC), D-dimer, and soluble fibrin monomer (SFM) were significantly higher in patients with DIC than in those with pre-DIC or non-DIC; the levels of these hemostatic markers were significantly higher in patients with pre-DIC than in those with non-DIC. Plasma levels of thrombin-antithrombin complex (TAT) were significantly higher in patients with DIC or pre-DIC than in those with non-DIC. Plasma levels of tissue factor (TF), total TFPI, free TFPI, and TFPI-Xa complex were significantly higher in patients with DIC than in those with non-DIC. Plasma levels of TFPI-Xa complex were significantly increased in patients with pre-DIC as compared to those with non-DIC; however, plasma free TFPI levels were significantly decreased in patients with pre-DIC as compared to those with non-DIC. These findings suggest that free TFPI might be consumed in the pre-DIC state, thereby confirming the activation of the extrinsic pathway. Plasma levels of TFPI-Xa complex were significantly correlated with TF, free TFPI, and total TFPI. Increased plasma TFPI-Xa complex levels might be useful for the diagnosis of DIC or pre-DIC, particularly that occurring by activation of the extrinsic pathway of blood coagulation.

Total replacement of the aorta and the inferior vena cava after resection of an extra-adrenal malignant pheochromocytoma

Extra-adrenal malignant pheochromocytomas are difficult to operate on because of a tight adhesion to the circumference of tumors. However, an operation is the most curable treatment. Sometimes a replacement of the inferior vena cava with grafts is necessary for removing tumors completely. We totally replaced the aorta and the inferior vena cava after resection of an extra-adrenal malignant pheochromocytoma. No recurrence has been detected, and the aortic graft has had a good patency after 36 months postoperatively. But the vena caval graft has had no patency after 21 months postoperatively.

Mechanism of anti-tumor effect of combination of bleomycin and shock waves

We have previously reported marked enhancement of the cytocidal effect of bleomycin (BLM) on cancer cell suspensions in vitro by the combination with shock waves. In this study, we evaluated the synergistic effects on cancer cell proliferation and apoptosis in solid tumors. A spherical piezo-ceramic element was used as the shock wave source, with a pressure peak of 40 MPa. A human colon cancer cell line, SW480 was implanted onto the back of nude mice. Two thousand shock waves were administered to the tumor immediately following an intravenous injection of BLM at a dose of one-tenth of the LD(50). The tumor was extirpated at 3, 6, 12, 24, 72 h and 1 week following shock exposure. Cell proliferation and apoptosis were detected by Ki-67 using antibody MIB-1 and by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) method. The lowest percentage (35.7%) of Ki-67-positive cells appeared 24 h following the treatment. The maximum apoptotic index was detected within 6 h following the treatment. Moreover, numerous large cells with enlarged nuclei were detected histologically. These results suggest that shock waves may enhance chemotherapeutic effects by increasing apoptosis and decreasing cell proliferation in the tumor tissue.

Controlling malignant pericardial effusion by intrapericardial carboplatin administration in patients with primary non-small-cell lung cancer

Malignant pericarditis, when associated with massive pericardial effusion, presents a critical condition in lung cancer patients. Because this condition often arises in terminally ill patients, intensive therapy such as multi-drug combination chemotherapy is rarely appropriate. This study evaluated the clinical relevance of intrapericardial administration of carboplatin for controlling malignant pericardial effusions associated with non-small-cell lung carcinoma (NSCLC). The method used for 10 eligible patients consisted of draining the pericardial effusion and infusing 300 mg/body of carboplatin in 50 ml of saline through an in-place catheter into the pericardial space and clamping the catheter for 40 min. Nine of the 10 patients showed satisfactory results, and 8 experienced complete regression of the effusion. No major or minor adverse effects were observed. Pharmacokinetics analysis revealed that the concentration of free platinum in the pericardial fluid was very high while that of total platinum in the circulating plasma was very low, assuring the usefulness of the intrapericardial instillation of carboplatin in terminally ill patients for controlling malignant pericardial effusion when the systemic delivery of cytotoxic agents is inappropriate.

Plasma levels of activated protein C-protein C inhibitor complex in patients with hypercoagulable states

Plasma levels of activated protein C (APC)-protein C inhibitor (PCI) were significantly increased in patients with disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), acute myocardial infarction (AMI), pulmonary embolism (PE), or deep vein thrombosis (DVT) and in patients undergoing hemodialysis (HD). Plasma levels of APC-alpha(1)-antitrypsin (AT) complex were significantly increased in patients with DIC and in those with TTP. Plasma levels of PCI were significantly decreased in patients with DIC, non-DIC, or TTP and in those undergoing HD. In the pre-DIC stage, the plasma levels of APC-PCI complex were significantly increased but not those of APC-alpha(1)-AT complex. These data suggest that measurements of APC-PCI complex and APC-alpha(1)-AT complex may be useful for the diagnosis of DIC. After treatment of DIC, the plasma levels of APC-PCI complex and APC-alpha(1)-AT complex were significantly decreased, but not those of PCI. Plasma levels of thrombin-antithrombin complex (TAT), plasmin-alpha(2)-plasmin complex (PPIC), D-dimer, and soluble fibrin monomer (SFM) were markedly increased in patients with DIC or pre-DIC and were moderately increased in patients with non-DIC, TTP, AMI, PE, or DVT and in those undergoing HD. The receiving operating characteristic (ROC) analysis showed that SFM and the APC-PCT complex are useful markers for diagnosis of DIC. The specificity of plasma TAT and PPIC levels was low. The positive rate of APC-PCI complex was higher than 90% with DIC, TTP, AMI, PE, and it was higher than 60% with DVT and HD. Since the APC-PCI complex was elevated not only in patients with venous thrombosis but also in those with arterial thrombosis, components of the protein C pathway might be useful markers for the diagnosis of arterial thrombosis.

Initial enzyme for glycosylphosphatidylinositol biosynthesis requires PIG-P and is regulated by DPM2

Glycosylphosphatidylinositols (GPIs) are attached to the C-termini of many proteins, thereby acting as membrane anchors. Biosynthesis of GPI is initiated by GPI-N-acetylglucosaminyltransferase (GPI-GnT), which transfers N-acetylglucosamine from UDP- N-acetylglucosamine to phosphatidylinositol. GPI-GnT is a uniquely complex glycosyltransferase, consisting of at least four proteins, PIG-A, PIG-H, PIG-C and GPI1. Here, we report that GPI-GnT requires another component, termed PIG-P, and that DPM2, which regulates dolichol-phosphate-mannose synthase, also regulates GPI-GnT. PIG-P, a 134-amino acid protein having two hydrophobic domains, associates with PIG-A and GPI1. PIG-P is essential for GPI-GnT since a cell lacking PIG-P is GPI-anchor negative. DPM2, but not two other components of dolichol-phosphate-mannose synthase, associates with GPI-GnT through interactions with PIG-A, PIG-C and GPI1. Lec15 cell, a null mutant of DPM2, synthesizes early GPI intermediates, indicating that DPM2 is not essential for GPI-GnT; however, the enzyme activity is enhanced 3-fold in the presence of DPM2. These results reveal new essential and regulatory components of GPI-GnT and imply co-regulation of GPI-GnT and the dolichol-phosphate-mannose synthase that generates a mannosyl donor for GPI.

Depressive behavior and alterations in receptors for dopamine and 5-hydroxytryptamine in the brain of the senescence accelerated mouse (SAM)-P10

The senescence accelerated mouse (SAM) is known as a murine model of aging. SAM consists of senescence accelerated-prone mouse (SAMP) and senescence accelerated-resistant mouse (SAMR). Previous studies reported that SAMP10 exhibits age-related learning impairments and behavioral depression in a tail suspension test after 7 months. We investigated the changes in emotional behavior in a forced swimming test and in receptors for dopamine and 5-hydroxytryptamine (5-HT) in SAMP10. SAMP10 at 8 months showed an increase of immobility in the test compared with SAMR1. Treatment with desipramine (25 mg/kg, i.p., 3 days) in SAMP10 caused a decrease in immobility. In the cortex from SAMP10, [3H]quinpirole binding to D2/D3 dopamine receptors increased significantly compared with control SAMR1. In the hippocampus from SAMP10, [3H]8-hydroxy DPAT binding to 5-HT1A receptor increased. In midbrains from SAMP10, bindings of [3H]quinpirole and [3H]8-hydroxy DPAT increased. [3H]SCH23390 binding to D1/D5 receptors and [3H]ketanserin binding to 5-HT2 receptor in brain regions examined in SAMP10 were similar to those in SAMR1. The present findings represent the first neurochemical evidence of an increase of D2/D3 and 5-HT1A receptors in SAMP10. SAMP10 may be a useful model of aging associated depressive behavior.

Requirement of PIG-F and PIG-O for transferring phosphoethanolamine to the third mannose in glycosylphosphatidylinositol

Many eukaryotic proteins are anchored by glycosylphosphatidylinositol (GPI) to the cell surface membrane. The GPI anchor is linked to proteins by an amide bond formed between the carboxyl terminus and phosphoethanolamine attached to the third mannose. Here, we report the roles of two mammalian genes involved in transfer of phosphoethanolamine to the third mannose in GPI. We cloned a mouse gene termed Pig-o that encodes a 1101-amino acid PIG-O protein bearing regions conserved in various phosphodiesterases. Pig-o knockout F9 embryonal carcinoma cells expressed very little GPI-anchored proteins and accumulated the same major GPI intermediate as the mouse class F mutant cell, which is defective in transferring phosphoethanolamine to the third mannose due to mutant Pig-f gene. PIG-O and PIG-F proteins associate with each other, and the stability of PIG-O was dependent upon PIG-F. However, the class F cell is completely deficient in the surface expression of GPI-anchored proteins. A minor GPI intermediate seen in Pig-o knockout but not class F cells had more than three mannoses with phosphoethanolamines on the first and third mannoses, suggesting that this GPI may account for the low expression of GPI-anchored proteins. Therefore, mammalian cells have redundant activities in transferring phosphoethanolamine to the third mannose, both of which require PIG-F.

Coagulation tests and anti-phospholipid antibodies in patients positive for lupus anticoagulant

We examined activated partial thromboplastin time, kaolin clotting time, mixing with normal plasma in kaolin clotting time, dilute Russell's viper venom time, dilute Russell's viper venom time at high lipid concentrations, anti-phospholipid antibodies, and anti-cardiolipin-beta2-glycoprotein I complex antibody in 135 patients with prolongation of activated partial thromboplastin time and diagnosed 86 patients positive for lupus anticoagulant. The sensitivity of activated partial thromboplastin time and dilute Russell's viper venom time/dilute Russell's viper venom time-high lipid concentrations ratio for lupus anticoagulant were markedly high, but the specificity of activated partial thromboplastin time for lupus anticoagulant was not markedly high. The specificity, but not the sensitivity, of kaolin clotting time-mixing with normal plasma in kaolin clotting time was markedly high. In summary, dilute Russell's viper venom time to dilute Russell's viper venom time-high lipid concentrations ratio gave high sensitivity as well as specificity, being the only assay to confirm this. Of the patients positive for lupus anticoagulant, 25% were positive for anti-phospholipid antibodies and 17% were positive for anti-cardiolipin-beta2-glycoprotein I complex antibody. Of the lupus anticoagulant-positive patients with thrombosis, 45% were positive for anti-phospholipid antibodies, 35% were positive for anti-cardiolipin-beta2-glycoprotein I complex antibody, 60% were positive for both anti-phospholipid antibodies and anti-cardiolipin-beta2-glycoprotein I complex antibody, and only 17% were negative for anti-phospholipid antibodies and anti-cardiolipin-beta2-glycoprotein I complex antibody. These findings suggest that lupus anticoagulant can be diagnosed by dilute Russell's viper venom time/dilute Russell's viper venom time-high lipid concentrations ratio, and that thrombosis in lupus anticoagulant-positive may be predictable from both anti-phospholipid antibodies and anti-cardiolipin-beta2-glycoprotein I complex antibody. Plasma tissue type plasminogen activator level in lupus anticoagulant patients was significantly increased, and plasma tissue type plasminogen activator and fibrin-D-dimer levels in lupus anticoagulant-positive patients with thrombosis were significantly higher than in those without thrombosis, suggesting that the diagnosis of thrombosis by hemostatic markers might be important in lupus anticoagulant.

Activating transcription factor-2 is a positive regulator in CaM kinase IV-induced human insulin gene expression

Insulin plays a crucial role in the regulation of glucose-homeostasis, and its synthesis is regulated by several stimuli. The transcription of the human insulin gene, enhanced by an elevated intracellular concentration of calcium ions, was completely blocked by Ca2+/calmodulin-dependent protein kinase inhibitor. The activity of the transcription factor activating transcription factor-2 (ATF-2), which binds to the cAMP responsive elements of the human insulin gene, was enhanced by Ca2+/calmodulin-dependent protein kinase IV (CaMKIV). Mutagenesis studies showed that Thr69, Thr71, and Thr73 of ATF-2 are all required for activation by CaMKIV. CaMKIV-induced ATF-2 transcriptional activity was not altered by activation of cJun NH2-terminal protein kinase (JNK) or p38 mitogen-activated protein (MAP) kinase. Furthermore, when transfected into rat primary cultured islets, ATF-2 enhanced glucose-induced insulin promoter activity, whereas cAMP response element-binding protein (CREB) repressed it. These results suggest a mechanism in which ATF-2 regulates insulin gene expression in pancreatic beta-cells, with the transcriptional activity of ATF-2 being increased by an elevated concentration of calcium ions.

Decreased tissue factor and tissue-plasminogen activator antigen in relapsed acute promyelocytic leukemia

This study evaluated hemostatic data in 28 patients with newly diagnosed acute promyelocytic leukemia (APL) and 15 patients with relapsed APL. Activated partial thromboplastin time and prothrombin time were prolonged at initial onset of APL. Plasma level of fibrinogen was significantly decreased in patients with initial disease of APL, but it was not decreased significantly during the relapse of APL. Plasma fibrin and fibrinogen degradation products levels were significantly increased and platelet counts significantly decreased in both groups. Plasma levels of antiplasmin significantly decreased at initial onset but not during relapse. Plasma levels of antithrombin were within normal range in patients with initial disease but significantly decreased in those with relapse. Plasma levels of D-dimer, soluble fibrin monomer (sFM), plasmin-plasmin inhibitor complex (PPIC), and thrombin antithrombin complex (TAT) levels were significantly high in both groups. Plasma levels of PPIC, sFM, and D-dimer were significantly higher at initial onset of APL than during relapse. However, there was no significant difference in DIC score between patients with initial onset and those with relapse; plasma levels of tissue factor (TF) significantly increased in both groups, but they were significantly higher at initial onset of APL than during relapse. TF and tissue type plasminogen activator (t-PA) antigen levels in leukemic cell lysate were significantly increased in both groups, and they were significantly lower during relapse than at initial onset. Hemostatic abnormalities occurring in patients with relapsed APL might be the result of the decrease of TF and t-PA in leukemic cells. These findings suggest that DIC in APL patients with relapse might not be caused only by TF and t-PA and thus should be treated with different therapy from patients with initial onset of APL.

Erythema exsudativum multiforme induced by granulocyte colony-stimulating factor in an allogeneic peripheral blood stem cell donor

We describe a healthy peripheral blood stem cell (PBSC) donor who developed a cutaneous reaction, erythema exsudativum multiforme, during the administration of granulocyte colony-stimulating factor (G-CSF) for mobilization. The cutaneous lesions were located on his hips, apart from the site of G-CSF injection. Treatment with topical corticosteroid was commenced, and the lesions resolved completely within a week. Adverse cutaneous reactions induced by G-CSF have been reported infrequently in healthy donors. Further documentation of cases and their full evaluation will be of great importance for both physicians and PBSC donor.

Extracorporeal shock wave lithotripsy for a ureteral stone in crossed fused renal ectopia

BACKGROUND

A 63-year-old woman presented with right flank pain and macroscopic hematuria.

RESULTS/METHODS

A plain film showed a calcific shadow on the right iliac bone. On excretory urography, the right kidney was seen in the normal position, but the left kidney was not. Bilateral retrograde pyelogram revealed the S-shaped kidney and mild obstruction from a 12 x 5 mm calculus in the proximal ureter of the crossed kidney. The patient was successfully treated with in situ extracorporeal shock wave lithotripsy (ESWL) treatment and is stone free at 1 month follow up.

CONCLUSION

We believe this is the first case of successful ESWL in a crossed kidney.

Chronic unilateral ureteral obstruction represented as renin-dependent hypertension

A 50-year-old woman developed renin-dependent hypertension immediately after accidental unilateral ureteral ligation during hysterectomy, and the hypertension lasted for 5 months. Surgical release of the obstruction was carried out 157 days after the ligation. Then, her blood pressure was normalized. However, the obstructed kidney showed intensive tubulointerstitial fibrosis and functional recovery was not obtained. This case suggests that the renin-angiotensin system may be upregulated in human kidney during unilateral ureteral obstruction for a long duration.

The Japanese multicenter open randomized trial of ursodeoxycholic acid prophylaxis for hepatic veno-occlusive disease after stem cell transplantation

Hepatic veno-occlusive disease (VOD) is a common transplant-related complication of stem cell transplantation. There is no safe and proven therapy for established VOD, and attempts have focused on its prevention. Limited studies have suggested that prophylactic use of ursodeoxycholic acid (UDCA) reduced the incidence of VOD. To confirm the preventive effect of UDCA on VOD, we conducted a prospective, unblinded randomized, multicenter study of UDCA involving 132 patients who underwent stem cell transplantation for a variety of disorders. Sixty-seven patients were assigned to the UDCA-treated group, and 65 patients were assigned to the control group. The clinical characteristics of the two groups were similar with respect to primary diagnosis, age, sex, and baseline organ function. The preparative regimen and GVHD prophylaxis did not differ significantly between the two groups. UDCA was highly effective in preventing VOD, which occurred in only 3.0% in the UDCA-treated group, as opposed to 18.5% in the control group (P = 0.0043). There were no adverse effects attributable to UDCA. The initial promising report of a prophylactic effect of UDCA on VOD after stem cell transplantation was confirmed in this prospective study.

The Japanese multicenter open randomized trial of ursodeoxycholic acid prophylaxis for hepatic veno-occlusive disease after stem cell transplantation

Hepatic veno-occlusive disease (VOD) is a common transplant-related complication of stem cell transplantation. There is no safe and proven therapy for established VOD, and attempts have focused on its prevention. Limited studies have suggested that prophylactic use of ursodeoxycholic acid (UDCA) reduced the incidence of VOD. To confirm the preventive effect of UDCA on VOD, we conducted a prospective, unblinded randomized, multicenter study of UDCA involving 132 patients who underwent stem cell transplantation for a variety of disorders. Sixty-seven patients were assigned to the UDCA-treated group, and 65 patients were assigned to the control group. The clinical characteristics of the two groups were similar with respect to primary diagnosis, age, sex, and baseline organ function. The preparative regimen and GVHD prophylaxis did not differ significantly between the two groups. UDCA was highly effective in preventing VOD, which occurred in only 3.0% in the UDCA-treated group, as opposed to 18.5% in the control group (P = 0.0043). There were no adverse effects attributable to UDCA. The initial promising report of a prophylactic effect of UDCA on VOD after stem cell transplantation was confirmed in this prospective study.

Two brothers with frontotemporal dementia and parkinsonism with an N279K mutation of the tau gene

OBJECTIVE

To characterize the clinical diagnostic features, neuropathologic phenotype of tau deposition, and subunit structure of tau filaments in patients who had an asparagine-to-lysine substitution at codon 279 (the N279K missense mutation) of the gene for microtubule-associated tau protein.

BACKGROUND

The N279K mutation is a causative genetic defect for pallidopontonigral degeneration in an American kindred that presents with frontotemporal dementia (FTD) and parkinsonism.

METHODS

The authors analyzed retrospectively the clinical symptoms of two Japanese brothers who carry this mutation. Postmortem neuropathologic and electron microscopic studies, and Western blot analysis of insoluble tau were performed to correlate tau-mediated lesions with neurologic deficits.

RESULTS

Both patients exhibited impairment in recent memory, parkinsonism, and corticospinal disturbances in addition to FTD. Parkinsonism in one patient was responsive temporarily to l-dopa. There was intense tau deposition in the medial temporal cortices and upper and lower motor neurons with accompanying corticospinal tract degeneration. Two distinct tau isoforms with four microtubule-binding repeats, in hyperphosphorylated forms, were the primary constituents of insoluble tau, which aggregated to the filamentous component, termed "paired tubules," in neurons, oligodendrocytes, and astrocytes. The elemental filaments were hollow tubules measuring 11 to 12 nm in diameter, two of which adhered to each other along their longitudinal axes to form "paired tubules."

CONCLUSIONS

Early memory loss and pyramidal signs, which are atypical of FTD, can be presenting symptoms in this disorder. The authors demonstrated that the subunit structure of tau filaments is a pair of hollow tubules despite the prevailing twisted ribbon model.

The Japanese multicenter open randomized trial of ursodeoxycholic acid prophylaxis for hepatic veno-occlusive disease after stem cell transplantation

Hepatic veno-occlusive disease (VOD) is a common transplant-related complication of stem cell transplantation. There is no safe and proven therapy for established VOD, and attempts have focused on its prevention. Limited studies have suggested that prophylactic use of ursodeoxycholic acid (UDCA) reduced the incidence of VOD. To confirm the preventive effect of UDCA on VOD, we conducted a prospective, unblinded randomized, multicenter study of UDCA involving 132 patients who underwent stem cell transplantation for a variety of disorders. Sixty-seven patients were assigned to the UDCA-treated group, and 65 patients were assigned to the control group. The clinical characteristics of the two groups were similar with respect to primary diagnosis, age, sex, and baseline organ function. The preparative regimen and GVHD prophylaxis did not differ significantly between the two groups. UDCA was highly effective in preventing VOD, which occurred in only 3.0% in the UDCA-treated group, as opposed to 18.5% in the control group (P = 0.0043). There were no adverse effects attributable to UDCA. The initial promising report of a prophylactic effect of UDCA on VOD after stem cell transplantation was confirmed in this prospective study.

Interferon therapy for renal cell carcinoma in hemodialysis patients: report of two patients

The method of interferon therapy has not been clarified in hemodialysis patients with renal cell carcinoma. Two hemodialysis patients with renal cell carcinoma were treated with natural interferon-alpha. The serum levels of interferon-alpha in both patients were measured after 24, 48, 72 and 96 h of injection. In case 1, the serum concentration of interferon-alpha after 24 h of injection at a dose of 3 x 10(6) reached a maximum and decreased gradually. In case 2, the serum concentration of interferon-alpha reached a maximum 24 h after injection at a dose of 3 x 10(6) and decreasing gradually after this. After an injection of interferon-alpha at a concentration of 6 x 10(6) 7 days later, the serum concentration of interferon-alpha reached a maximum 48 h after the injection and decreased gradually thereafter. The serum interferon-alpha concentrations of these cases were higher than normal renal function patients in other literature. It is necessary to modify the interval between injections for hemodialysis patients with renal cell carcinoma.

[Serum tumor markers for primary lung carcinoma]

A number of serum tumor markers are clinically relevant for primary lung carcinomas. None of them, however, is applied to screening of lung cancers because of their unsatisfactory sensitivity and specificity. Among them, measurements of CEA, CYFRA 21-1, NSE, and pro GRP frequently give subsidiary information as to differential diagnosis, monitoring of treatment, and early detection of recurrence. Current trend of the tumor markers for lung cancer includes development of new markers such as p53 tumor suppressor gene product and I-CTP for detecting bone metastasis. Attempts to detect micrometastases by means of RT-PCR of these marker genes are also discussed.

Long-term survival of transmural advanced gastric carcinoma following curative resection: multivariate analysis of prognostic factors

Patients with transmural (T2N0-T3N2) advanced gastric carcinoma comprise the largest group with uncertain outcome. These patients must be stratified according to the prognostic variables so the high risk group can be precisely identified. A total of 152 patients with transmural advanced gastric carcinomas were uniformly treated with a curative intent between 1979 and 1989 with at least a 7-year follow-up. Results and prognostic factors of long-term survival were analyzed by univariate and multivariate analyses. Seventy-five (49%) patients with advanced gastric carcinoma survived more than 7 years, which indicates the curative nature of surgery for gastric carcinoma. Seventeen variables were evaluated by univariate analysis. In the multivariate analysis, patient's age [>70 years, relative risk (RR) 2.4)], intraoperative blood loss (>500 ml, RR 1.7), blood vessel invasion (RR 2.3), ratio of invaded dissected lymph nodes (>0.2, RR 3.0), and tumors penetrating the serosa (RR 3.9) were the independent prognostic variables. The results of this study indicate that extensive lymphadenectomy and minimal intraoperative blood loss might be helpful for improving patient survival following a curative resection. Patients with vessel invasion, serosal involvement, and those >70 years of age should be considered at high risk and require appropriate adjuvant therapy to prolong survival.

The effect of age on inflammatory responses and nerve root injuries after lumbar disc herniation: an experimental study in a canine model

STUDY DESIGN

An experimental investigation on the effect of age on pathologic events surrounding the herniated disc and at the adjacent nerve root.

OBJECTIVES

To investigate the role of age on the inflammatory responses and nerve root damage surrounding a sequestered lumbar disc fragment using a dog model.

SUMMARY OF BACKGROUND DATA

Lumbar disc herniation is manifested in patients by variable clinical findings, natural history, and resorption phenomena in which the variability is particularly noted among patients with different ages. There are no previous reports on the effect of age on pathologic events induced by the herniated disc.

METHODS

Six beagle dogs, including two animals of each age group of 6, 12, and 24 months (human equivalent ages of 10, 15, and 24 years), were used in this study. The dogs underwent L4-L5, L5-L6, and L6-L7 laminotomy and discectomy under general anesthesia. An autologous intervertebral disc from the tail was divided into anulus fibrosus and nucleus pulposus fragments. The anulus fibrosus and nucleus pulposus fragments were placed in the anterolateral epidural space of L5-L6 and L6-L7, respectively. The L4-L5 discectomy site served as a control. Dogs were killed at 12 weeks after surgery. The lumbar spine was removed en bloc, and histologic sections were prepared consecutively and examined.

RESULTS

In the nucleus pulposus group at L6-L7, neovascularity, and intensive infiltration of lymphocytes, macrophages, and fibroblasts were observed surrounding the nucleus pulposus fragment in the 24-month-old group only. Degenerative changes of the nerve root fibers were observed in the 24-month-old group only. In the control and anulus fibrosus groups at L4-L5 and L5-L6, there were no marked inflammatory reactions in all age groups. The nerve root fibers around the anulus fibrosus were normal in all age groups.

CONCLUSIONS

There is an effect of age on the inflammatory response and nerve root injury caused by the herniated disc. The apparent neuroprotective mechanism in the young animal, and the apparent inflammatory and resorption changes of the nucleus pulposus fragment in the older animal are quite intriguing.

Learning deficiency and alterations in acetylcholine receptors and protein kinase C in the brain of senescence-accelerated mouse (SAM)-P10

The senescence-accelerated mouse (SAM) is known to be a murine model for accelerated aging. A novel inbred SAMP10 has shown age-related brain atrophy and learning deficiency. In the present study, we investigated the changes in learning ability and in ligand binding with muscarinic acetylcholine (mACh) receptors, alpha adrenoceptors and protein kinase C in SAMP10. In Morris's water maze task, in a control strain of SAMR1 at 9 months, the escape latency and path length decreased with increasing trial days, in contrast, escape latency and path length did not decrease in SAMP10. These results indicate that SAMP10 exhibits learning deficiency. The ligand binding activity of mACh receptors decreased in the hippocampus of SAMP10 and the protein kinase C level in the hippocampus of SAMP10 was lower than that of SAMR1. On the other hand, there was no significant difference between SAMR1 and SAMP10 regarding ligand binding activity of alpha(1) and alpha(2) adrenoceptors. Thus, a reduction of mACh receptors and protein kinase C in the brain seems to underlie dysfunction of learning and memory in SAMP10.

Risk-adapted pre-emptive therapy for cytomegalovirus disease in patients undergoing allogeneic bone marrow transplantation

We prospectively evaluated a risk-adapted pre-emptive treatment with ganciclovir for CMV diseases in patients undergoing allogeneic bone marrow transplantation (BMT). High-level CMV antigenemia (10 or more positive cells on two slides) or CMV antigenemia at any level in patients with grade II-IV acute graft-versus-host disease (aGVHD) were chosen as risk factors. We also retrospectively evaluated virus reactivation in plasma using quantitative real-time polymerase chain reaction (PCR). Fifty patients were evaluable. None of the 27 patients with or without grade I aGVHD developed high-level CMV antigenemia or CMV disease. Among the 23 patients with grade II-IV aGVHD, 12 patients (52%) developed CMV antigenemia and were treated pre-emptively, of whom two developed CMV gastroenteritis or retinitis in spite of therapy. Six of the remaining 11 patients developed CMV gastroenteritis before CMV antigenemia was detectable. All of the eight patients with CMV diseases were successfully treated with ganciclovir and no deaths directly related to CMV disease occurred. In four of the seven evaluable patients with CMV gastroenteritis, real-time PCR was able to detect virus reactivation earlier than CMV antigenemia. Although our risk-adapted pre-emptive therapy effectively reduced CMV-related mortality, further refinements of this approach, particularly in the prevention of CMV gastroenteritis, may be achieved by incorporating real-time PCR.

Collection of peripheral blood stem cells with granulocyte-colony-stimulating factor alone in testicular cancer patients

BACKGROUND

High-dose chemotherapy with the transplantation of peripheral blood stem cells (PBSC) has been performed for the treatment of advanced testicular cancer patients. Recently, it has been reported that, in healthy donors, a large quantity of stem cells can be transferred to peripheral blood using granulocyte-colony-stimulating factor (G-CSF) alone. Therefore, it was decided to try to harvest PBSC from three patients having testicular cancers with G-CSF alone.

METHODS

The three patients with testicular cancer were 26, 56 and 62-years-old. They had undergone five, two and three cycles of chemotherapy, respectively, but no radiation therapy. Granulocyte colony-stimulating factor was subcutaneously injected (250 microg) into each patient twice per day for 6 days. Peripheral blood stem cells were harvested for 3 days (days 4-6) and mononuclear cells (MNC), CD34-positive cells and colony-forming units of granulocyte-macrophage (CFU-GM) in PBSC collected by apheresis were measured.

RESULTS

Apheresis showed that the total MNC count was 20.2 x 10(8)/kg (range, 10.6-25.9 x 10(8)/kg), the CD34-positive cell count was 0.98 x 10(6)/kg (range, 0.75-1.4 x 10(6)/kg) and the total CFU-GM count was 1.36 x 10(5)/kg (range, 0.25-3.0 x 10(5)/kg).

CONCLUSION

After mobilization of peripheral blood stem cells with G-CSF alone, sufficient amounts of MNC were obtained from testicular cancer patients who had undergone chemotherapy several times. However, sufficient amounts of CD34-positive cells and CFU-GM could not be obtained. These results suggested that the G-CSF dose was not adequate for harvesting sufficient amounts of CD34-positive cells and CFU-GM.

Molecular identification of a human carcinoma-associated glycoprotein antigen recognized by mouse monoclonal antibody FU-MK-1

Mouse monoclonal antibody FU-MK-1, raised against a human gastric adenocarcinoma, recognizes an antigen (termed MK-1 antigen) present on the majority of carcinomas. The present study aimed to identify the MK-1 molecule and to establish its relationship to other carcinoma antigens. Immunoprecipitation studies of human tumor cell lines revealed that FU-MK-1 recognizes a monomeric membrane glycoprotein with two forms, 40 kDa (major form) and 42 kDa (minor form), and with a molecular mass of 35 kDa following treatment with the N-glycosylation inhibitor tunicamycin. The partial amino acid sequence of a main fragment of the MK-1 molecule obtained by spontaneous cleavage under hypotonic conditions was examined, and the 17 contiguous NH2-terminal amino acids were found to be identical with residues 81-97 of the 314-residue GA733-2 protein [Szala et al.; Proc. Natl. Acad. Sci. USA, 87, 3542-3546 (1990)]. Hence, the GA733-2 cDNA was cloned and the specificity of FU-MK-1 was confirmed using four recombinant forms of the GA733-2 antigen expressed in COS-1 cells. Immunoprecipitation with FU-MK-1 of the cell lysate transfected with the full-length GA733-2 cDNA revealed two bands corresponding to those obtained from the tumor cell lines. FU-MK-1 also precipitated three other recombinant proteins consisting of amino acids 1-265, 1-201, and 1-139 of the GA733-2 protein, respectively. Furthermore, immunoblotting analysis indicated that FU-MK-1 binds to a small fragment (6 kDa) generated from a tumor cell line under hypotonic conditions, suggesting that the FU-MK-1 epitope exists on the distal 6-kDa peptide of the extracellular domain of the GA733-2 molecule. We thus conclude that the MK-1 antigen is the GA733-2 antigen, which is currently being used as a target in clinical trials with monoclonal antibodies.

Properties of the naturally occurring soluble surface glycoprotein of ecotropic murine leukemia virus: binding specificity and possible conformational change after binding to receptor

Ecotropic murine leukemia virus (MuLV) infection is initiated by the interaction between the surface glycoprotein (SU) of the virus and its cell-surface receptor mCAT-1. We investigated the SU-receptor interaction by using a naturally occurring soluble SU which was encoded by the envelope (env) gene of a defective endogenous MuLV, Fv-4(r). Binding of the SU to mCAT-1-positive mouse cells was completed by 1 min at 37 degrees C. The SU could not bind to mouse cells that were persistently infected by ecotropic MuLVs (but not amphotropic or dualtropic MuLVs) or transfected with wild-type ecotropic env genes or a mutant env gene which can express only precursor Env protein that is restricted to retention in the endoplasmic reticulum. These cells were also resistant to superinfection by ecotropic MuLVs. Thus, superinfection resistance correlated with the lack of SU-binding capacity. After binding to the cells, the SU appeared to undergo some conformational changes within 1 min in a temperature-dependent manner. This was suggested by the different properties of two monoclonal antibodies (MAbs) reactive with the same C-terminal half of the Fv-4(r) SU domain, including a proline-rich motif which was shown to be important for conformation of the SU and interaction between the SU and the transmembrane protein. One MAb reacting with the soluble SU bound to cells was dissociated by a temperature shift from 4 to 37 degrees C. Such dissociation was not observed in cells synthesizing the SU or when another MAb was used, indicating that the dissociation was not due to a temperature-dependent release of the MAb but to possible conformational changes in the SU.

Elevated tissue factor levels in leukemic cell homogenate

Tissue factor (TF) antigen and activity were measured in leukemic cell homogenates. In leukemic cell homogenate, especially that of acute promyelocytic leukemia (APL), both TF antigen and activity were significantly higher than these levels in the mononuclear cells obtained from healthy volunteers. Both TF antigen and activity were significantly higher in myelocytic leukemia than in lymphocytic leukemia cells. In leukemic cell homogenates, there was a close correlation between TF antigen and TF activity. The TF activity/TF antigen ratio was significantly higher in myelocytic leukemia than in lymphocytic leukemia cells. As the TF activity was not increased in lymphocytic leukemia cell homogenates to which were added phospholipids, the decrease in TF activity in lymphocytic leukemia might not be due to phospholipid in the leukemic cell membrane. Values for TF activity, TF antigen, and the TF activity/TF antigen ratio in leukemic cell homogenate from patients with disseminated intravascular coagulation (DIC) were significantly higher than those in patients without DIC. Therefore, the measurement of TF antigen and activity in leukemic cells could be useful for the prediction of DIC.

Pig-n, a mammalian homologue of yeast Mcd4p, is involved in transferring phosphoethanolamine to the first mannose of the glycosylphosphatidylinositol

Many cell surface proteins are anchored to the membrane via a glycosylphosphatidylinositol (GPI) moiety, which is attached to the C terminus of the proteins. The core of the GPI anchor is conserved in all eukaryotes but is modified by various side chains. We cloned a mouse phosphatidylinositol glycan-class N (Pig-n) gene that encodes a 931amino acid protein expressed in the endoplasmic reticulum, which is homologous to yeast Mcd4p. We disrupted the gene in F9 embryonal carcinoma cells. In the Pig-n knockout cells, the first mannose in the GPI precursors was not modified by phosphoethanolamine. Nevertheless, further biosynthetic steps continued with the addition of the third mannose and the terminal phosphoethanolamine. The surface expression of Thy-1 was only partially affected, indicating that modification of the first mannose by phosphoethanolamine is not essential for attachment of GPI anchors in mammalian cells. An inhibitor of GPI biosynthesis, YW3548/BE49385A, inhibited transfer of phosphoethanolamine to the first mannose in mammalian cells but only slightly affected the surface expression of GPI-anchored proteins. Biosynthesis of GPI in the Pig-n knockout cells was not affected by YW3548/BE49385A, and yeast overexpressing MCD4 was highly resistant to YW3548/BE49385A, suggesting that Pig-n and Mcd4p are targets of this drug.

Immunohistochemical study of a patient with diffuse pulmonary corpora amylacea detected by open lung biopsy

The chest radiographs of an asymptomatic 58-year-old Japanese man with pulmonary corpora amylacea (PCA) revealed bilateral patchy and nodular infiltrates. Lung specimens obtained by open lung biopsy were histochemically and immunohistochemically analyzed. In all sections of dissected lung tissue, hematoxylin and eosin staining revealed homogeneous eosinophilic acellular round bodies (50-100 microm in diameter) containing granular black pigments in the alveolar spaces. Some round bodies were surrounded and phagocytized by alveolar macrophages. The laminated round bodies stained positively with PAS and Congo red. In addition, many of the rounded bodies contained particles which stained positively with Berlin blue. Immunohistochemical staining for epithelial membrane antigen (EMA) as well as PE-10 was distinctively positive. This is a very rare case of diffuse PCA found by open lung biopsy. Immunohistochemical examination suggested that PCA consisted of pulmonary surfactant protein and epithelial membrane antigen.

Use of N-[5-(5,7-dimethyl boron dipyrromethene difluoride-sphingomyelin to study membrane traffic along the endocytic pathway

We have used N-[5-(5,7-dimethyl boron dipyrromethene difluoride)-1-pentanoyl]-D-erythro-sphingosylphosphorylcholine (C5-DMB-SM or 'BODIPY-SM'), a fluorescent analog of sphingomyelin, to study lipid transport along the endocytic pathway of human skin fibroblasts. The unique spectral properties of the BODIPY fluorophore allow the investigator to distinguish various populations of labeled endosomes and lysosomes within the living cell by fluorescence microscopy, and in conjunction with quantitative fluorescence microscopy, to estimate the concentration of these lipids in different intracellular compartments. This methodology is also applicable for visualizing the accumulation of lipids in the endosomes and lysosomes of storage disease fibroblasts.