[Hard metal lung with diffuse small nodular shadows]

A 32-year-old woman was admitted to Niigata University Hospital with dyspnea and a non-productive cough. She had been exposed to hard metal dust for 4 years in a metal-polishing factory. Chest X-ray and CT films showed diffuse small nodular shadows in both lung fields and pulmonary-function tests revealed severe restrictive impairment. Specimens obtained by thoracoscopic lung biopsy showed fibrosis in the centers of lobules and in peribronchiolar regions. Giant-cell interstitial pneumonia-like findings were also noted. Tungsten carbide and cobalt were detected in these specimens, with an X-ray microanalyzer. Hard metal lung was diagnosed. By 1 year after she changed her place of work and began corticosteroid treatment her symptoms and pulmonary function had improved remarkably, although shadows on chest X-ray films remained to some extent.

Proximal and segmental motor nerve conduction in the sciatic nerve produced by percutaneous high voltage electrical stimulation

Percutaneous high voltage electrical stimulation was applied to the proximal sciatic nerve at the hip in 18 normal subjects to evaluate motor conduction in the proximal sciatic nerve, and short-segment stimulation of the sciatic and posterior tibial nerves was given in 6 normal subjects. Compound muscle action potentials (CMAPs) were recorded from the abductor hallucis (AH) and extensor digitorum brevis (EDB) muscles. Supramaximal stimulation was easily obtained at the proximal sciatic nerve and all the sites in the short-segment stimulation. The motor nerve conduction velocity of the sciatic nerve between the hip and the popliteal fossa was 49.2 +/- 4.24 m/sec in the tibial division and 54.1 +/- 6.48 m/sec in the peroneal division. The respective peak-to-peak amplitude and negative-peak areas of the CMAPs at the hip were reduced to 86.8 +/- 5.65% and 97.3 +/- 5.36% for the tibial division, and 93.4 +/- 7.06% and 96.8 +/- 5.09% for the peroneal division as compared to the values for the popliteal fossa. The negative-peak duration of the CMAPs at the hip point were increased to 109.2 +/- 7.2% for the tibial nerve and 107.1 +/- 5.68% for the peroneal nerve as compared with the duration at the popliteal fossa. This method is non-invasive and useful for evaluating motor nerve conduction in the lower limb.

The beta subunit of human granulocyte-macrophage colony-stimulating factor receptor forms a homodimer and is activated via association with the alpha subunit

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) receptor (hGMR) consists of alpha and beta subunits, and the precise stoichiometry of these subunits has remained to be determined. In this work, oligomerization of the beta subunit was studied using a chemical cross-linker. In Ba/F3, a mouse interleukin-3-dependent cell line expressing both subunits of hGMR (Ba/F3-alpha,beta), a protein with a molecular mass corresponding to that of a homodimer of the beta subunit (beta homodimer) was detected only when cells were treated with the cross-linker. Dimerization of the beta subunit was confirmed by coimmunoprecipitation of a tagged beta subunit with the wild type beta subunit COS7 cells. The beta homodimer had already formed in the absence of hGM-CSF, whereas stimulation with the ligand brought both alpha and beta subunits into a complex, the result being tyrosine phosphorylation of the beta homodimer. Tyrosine phosphorylation of the subunit was impaired by deletion of the cytoplasmic domain of the alpha subunit without interfering with the association of both subunits. These results indicate that the beta homodimer, which alone is insufficient for signaling, forms the functional hGMR with the alpha subunit in response to hGM-CSF.

Granulocyte-macrophage colony-stimulating factor provokes RAS activation and transcription of c-fos through different modes of signaling

Granulocyte-macrophage colony-stimulating factor (GM-CSF) provokes a proliferative response and induction of early-response genes such as c-fos in target cells. It also induces rapid tyrosine phosphorylation of cellular proteins, including the beta subunit (betac) of its functional receptor. However, locations and functions of phosphorylated tyrosine residues within the betac are unclear. To elucidate the mechanism of the human GM-CSF receptor signal transduction, mutational analyses were made of the cytoplasmic domain of the beta-c, using murine BA/F3 cells. Deletion of the conserved box 1 motif resulted in loss of tyrosine phosphorylation of the betac, thereby indicating an essential role for this motif in activating the tyrosine kinase which phosphorylates betac. A C-terminal truncated mutant at position 589 activated the c-fos promoter, and this activation was diminished by a substitution at tyrosine 577 (Tyr577). However, the same substitution in the full-length betac did not completely abrogate the c-fos promoter activation, hence, redundant signaling pathways probably exist. When we analyzed signaling molecules functioning downstream of the beta-c we found that Tyr577 is essential for Shc phosphorylation, while tyrosine phosphorylation of PTP1D was mediated through Tyr577 as well as through other site(s). We suggest that GM-CSF stimulates at least two modes of signals leading to Ras activation, an event which ultimately gives rise to promoter activation of c-fos.

Thymic carcinoma which developed in a thymic cyst

Thymic carcinoma was found in a thymic cyst in a 60-year-old woman who was admitted to our hospital due to cough and pain in her right chest. Chest X-ray showed a huge shadow in the right mediastinum. Chest CT scan showed a cystic tumor with a solid mass. An operation revealed a solid tumor in the thymic cyst. Pathologic diagnosis was squamous cell carcinoma, that contained some glandular tissues. The patient has been in a good condition for two years after the operation. Although the concurrent occurrence of thymic carcinoma and thymic cyst is very rare, it should be added to the differential diagnosis when anterior mediastinal cystic tumor is associated with a solid mass lesion.

Pathologic aspects of polytetrafluoroethylene sutures in human heart

BACKGROUND

Polytetrafluoroethylene (PTFE) sutures have been widely used as a mitral chord substitute. We present the cases of 4 patients who underwent mitral valve repair with chordal replacement by PTFE sutures and these required another operation. This gave us the chance to examine the PTFE sutures.

METHODS

Structural analysis of the PTFE sutures was performed 26 to 378 days postoperatively. The specimens were examined grossly, microscopically, and by scanning or transmission electron microscopy or both.

RESULTS

The PTFE suture in 1 patient was found to be completely covered with endothelial cells 154 days postoperatively. There was no calcification, and the flexibility and pliability of the PTFE sutures was preserved. Even though the PTFE sutures seemed uncovered on visual inspection, there was a thin lining of collagen and fibrin on the surface. Endothelial cells were seen in areas that looked clear in one specimen 26 days postoperatively.

CONCLUSIONS

We think that the new layer of collagen could be promising in terms of durability and that the endothelial layer wil resemble normal tissue in its anticoagulant properties.

[Septicemia associated with hematopoietic disorders and its features according to respective primary disorders]

Two hundred eighty-seven episodes of septicemia which occurred in patients with hematological disorders between 1980 and 1993 were examined according to respective underlying diseases. The diagnosis of acute myelogenous leukemia (AML) was made in 155 patients, acute lymphocytic leukemia (ALL) in 45, chronic myelogenous leukemia (CML) in 29, malignant lymphoma in 36, adult T-cell leukemia (ATL) in 7, multiple myeloma (MM) in 8 and aplastic anemia (AA) in 7. Three hundred and two strains were isolated from 287 patients. Fifty two point three percent of the total isolates were gram-negative bacilli, 26.8% were gram-positive cocci, 17.2% were fungi and 3.6% were anaerobic bacteria. In ALL patients gram-positive cocci accounted for 42.0%. This rate was significantly higher than in other disorder. Additionally, oral mucositis or gingivitis was evaluated as clinical background in 36.1% of ALL cases. Forty-seven point two percent of organisms which caused septicemia in ALL patients were isolated from surveillance cultures of the throat just before the onset of septicemia. These data suggested that in ALL cases microbiological organisms more frequently invaded through injuries of oral mucosa. In ATL, CML, MM and AA patients, fungi accounted for more than 25% of causative organisms. The most common organism of all of the strains was Pseudomonas aeruginosa (21.9%), but in ATL and MM patients Escherichia coli was more common than P. aeruginosa. At the onset of the septicemia, neutrophil counts were less than 100/mm3 in 76.6% of all patients, and more than 3,000/mm3 in only 5.0%. In contrast to this result, in 66.7% of ATL patients and 37.5% of MM patients, septicemia occurred even when neutrophil counts were more than 3,000/mm3. Septicemia occurred in 28.2% of the total patients but died. The mortality rate in MM and AA patients (50.0% respectively) was higher than in other diseases. According to the mortality of each causative organisms, fungal septicemia had a terribly high mortality of 82.9% while other bacterial mortality was about 20%.

Sympathetic skin response in Parkinson's disease

Sudomotor function in 83 patients with Parkinson's disease (PD) was evaluated using the sympathetic skin response (SSR) and sweat response to intradermal acetylcholine (ACh) injection. The incidence of abnormal SSRs (36.1%) increased, and the size of the response decrease with the severity of the illness. Neither the incidence of abnormal SSRs nor the amplitudes of the responses were influenced by levodopa or an anticholinergic agent. The SSR therefore can be used to evaluate the sudomotor efferent pathway in PD patients. In all the patients who had no SSR response, the local sweat response to ACh showed a reduced number of excitable sweat glands and low sweat volume. One patient, whose local sweat response to ACh was markedly impaired, had unmyelinated and acetylcholinesterase-positive fiber densities that were in the normal range in his biopsied sural nerve. The abnormal sweat response to ACh is considered to reflect the dysfunction of postganglionic sympathetic fibers in PD patients.

Colorimetric assay system for screening antiviral compounds against hepatitis B virus

A highly sensitive, rapid, and accurate assay system was developed for the in vitro evaluation of anti-hepatitis B virus (anti-HBV) agents. Chronic HBV-producing HB611 cells were used in combination with immunoaffinity purification, polymerase chain reaction (PCR), and hybrid capture detection. HB611 cells were incubated with putative anti-HBV agents for 7 days in 96-well microtiter plates. HBV was purified from HB611 cell culture media using immunoaffinity purification. The HBV DNA was extracted, amplified with PCR, and assayed using a hybrid capture colorimetric method. This assay provided quantitative detection of extracellular HBV DNA from 25 microliters of cell culture media. Using the colorimetric method, we found that 50% effective concentration levels of several known anti-HBV agents (HPMPA, PMEDAP, PMEA and others) were similar to those reported in studies using Southern blot analysis. These results demonstrate that this new and easily automated colorimetric assay system can be used for the rapid and accurate assessment of anti-HBV compound selectivity.

Identification of the sequence on NS4A required for enhanced cleavage of the NS5A/5B site by hepatitis C virus NS3 protease

In addition to NS3 protease, the NS4A protein is required for efficient cleavage of the nonstructural protein region of the hepatitis C virus polyprotein. To investigate the function and the sequence of NS4A required for the enhancement of NS3 protease activity, we developed an in vitro NS3 protease assay system consisting of three purified viral elements: (i) a recombinant NS3 protease which was expressed in Escherichia coli as a maltose-binding protein-NS3 fusion protein (MBP-NS3), (ii) synthetic NS4A fragments, and (iii) a synthetic peptide substrate which mimics the NS5A/5B junction. We showed that the NS3 protease activity of MBP-NS3 was enhanced in a dose-dependent manner by 4A18-40, which is a peptide composed of amino acid residues 18 to 40 of NS4A. The optimal activity was observed at a 10-fold molar excess of 4A18-40 over MBP-NS3. The coefficient for proteolytic efficiency, kcat/Km, of NS3 protease was increased by about 40 times by the addition of a 10-fold molar excess of 4A18-40. Using a series of truncations of 4A18-40, we estimated that amino acid residues 22 to 31 in NS4A (SVVIVGRIIL) constituted the core sequence for the effector activity. Single-substitution experiments with 4A21-34, a peptide composed of amino acid residues 21 to 34 of NS4A, suggested the importance of several residues (Val-23, Ile-25, Gly-27, Arg-28, Ile-29, and Leu-31) for its activity. In addition, we found that some single-amino-acid substitutions in 4A21-34 were able to inhibit the enhancement of NS3 protease activity by 4A18-40. This approach has potential as a novel strategy for inhibiting the NS3 protease activity important for hepatitis C virus proliferation.

[Nodular and cavitary pneumocystosis in a patient with hemophilia A and the acquired immunodeficiency syndrome]

A 25-year-old man with hemophilia A who had received concentrated plasma and plasma factor VIII products since childhood presented with a productive cough and a fever. The CD4/CD8 ratio of peripheral lymphocyte subsets was very low and the serum was positive for anti-HIV antibodies. The chest roentgenogram showed bilateral multiple nodules with cavity formation. The patient underwent transbronchial lung biopsy, and the specimen obtained had Pneumocystic carinii organisms. The patient was treated with sulfamethoxazole and trimethoprim compounds, and with inhaled pentamizine. His condition improved. Patients with pulmonary pneumocystosis usually present with interstitial infiltrates spreading from the hilium to the periphery of the lungs, and nodular and cavitary lesions are unusual pulmonary radiographic findings in this condition.

Hyaluronic acid synthesis by the malignant fibrous histiocytoma cell line NMSG 10 in vitro and its localization

Viscous material secreted from NMSG 10 cells cultured from malignant fibrous histiocytoma of human bone was demonstrated using two-dimensional electrophoresis to be glycosaminoglycans (GAGs) consisting of mainly hyaluronic acid (HA), along with small amounts of heparan sulfate (HS) and chondroitin sulfate (ChS). The biosynthesis of HA in a cell-free system was located at the plasma membrane fraction by colloidal-iron-reactive ultrastructural staining. The molecular weight of the HA synthesized by the plasma membrane fraction was estimated to be about 90,000 D by gel filtration. The material secreted by the original tumor tissue of NMSG 10 cells was demonstrated to be GAGs consisting of HA, HS, ChS and dermatan sulfate using two-dimensional electrophoresis. These findings suggest that transformed tumor cells could synthesize HA at the plasma membrane and release it into the stroma of tumor tissue.

Mechanism of selective inhibition of human immunodeficiency virus by ingenol triacetate

Ingenol 3,5,20-triacetate (ITA), one of the ingenol derivatives, is a selective inhibitor of human immunodeficiency virus (HIV) replication in vitro. ITA inhibited the replication of HIV strains in MT-4 cells at concentrations of 0.051 to 0.65 microM. This concentration was approximately 10(3)-fold lower than its cytotoxic threshold. The mechanism of action of ITA is primarily attributed to the inhibition of viral adsorption to the host cells, but it is distinct from the mechanism of inhibition by other adsorption inhibitors.

In vivo coupling of insulin-like growth factor II/mannose 6-phosphate receptor to heteromeric G proteins. Distinct roles of cytoplasmic domains and signal sequestration by the receptor

We examined the signaling function of the IGF-II/mannose 6-phosphate receptor (IGF-IIR) by transfecting IGF-IIR cDNAs into COS cells, where adenylyl cyclase (AC) was inhibited by transfection of constitutively activated G alpha i cDNA (G alpha i2Q205L). In cells transfected with IGF-IIR cDNA, IGF-II decreased cAMP accumulation promoted by cholera toxin or forskolin. This effect of IGF-II was not observed in untransfected cells or in cells transfected with IGF-IIRs lacking Arg2410-Lys2423. Thus, IGF-IIR, through its cytoplasmic domain, mediates the Gi-linked action of IGF-II in living cells. We also found that IGF-IIR truncated with C-terminal 28 residues after Ser2424 caused G beta gamma-dominant response of AC in response to IGF-II by activating Gi. Comparison with the G alpha i-dominant response of AC by intact IGF-IIR suggests that the C-terminal 28-residue region inactivates G beta gamma. This study not only provides further evidence that IGF-IIR has IGF-II-dependent signaling function to interact with heteromeric G proteins with distinct roles by different cytoplasmic domains, it also suggests that IGF-IIR can separate and sequestrate the G alpha and G beta gamma signals following Gi activation.

Immunological mechanisms in atherosclerosis

Immunological mechanisms seem to be potent modulators of the atherosclerotic process. The presence of substantial numbers of T-lymphocytes in the lesion and local and circulating autoantibodies to plaque components suggests that a specific immune response is operating. Focal expression of adhesion molecules and local secretion of chemoattractants could mediate the recruitment of inflammatory cells to the lesion. Local cytokine and growth factor networks may operate later, controlling cell migration and proliferation. Although it is still important to realize the complexity of these mechanisms, the ongoing characterization of the molecular mechanisms in atherogenesis may lead to new strategies for intervention with the disease process.

Differential expression of granulocyte-macrophage colony-stimulating factor and IL-3 receptor subunits on human CD34+ cells and leukemic cell lines

Cytokines transduce their signals through specific receptors. Receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-3, and IL-5 share the common signal transducing subunit (beta c), whereas the alpha subunits function as specific ligand binding components. In this study we prepared specific mouse monoclonal antibodies against human GM-CSF receptor-alpha subunit (hGMR alpha) by immunizing mice with Ba/F3 cells transfected with hGMR alpha complementary DNA. Using these anti-hGMR alpha antibodies in combination with antibodies against IL-3 receptor-alpha (IL-3R alpha), beta c subunits, and c-kit, we examined expression patterns and modulation of these receptor subunits on several human hematopoietic cells, including CD34+ cells and leukemic cell lines. GMR alpha and IL-3R alpha were expressed on GM-CSF- and IL-3-responsive cell lines, such as TF-1 and UT-7, whereas the expression levels were much lower on UT-7E, a GM-CSF- and IL-3-unresponsive subline of UT-7. The GMR alpha subunit was expressed only on mature granulocytes and monocytes, and IL-3R alpha was expressed on monocytes but not on mature granulocytes, and none of these subunits were expressed on lymphocytes. For CD34+ cells, GMR alpha was expressed more abundantly on CD34+ CD33high cells than on CD34+ CD33low cells, whereas IL-3R alpha was expressed more abundantly on CD34+ CD33low cells than on CD34+ CD33high and CD34+ CD33neg cells. Slight but significant expression of the beta c subunit was detected on CD34+ cells. Expression of not only GMR alpha and IL-3R alpha subunits but also c-kit was specifically downregulated by 48-hour incubation with their respective ligands. Receptor transmodulation between GM-CSF, IL-3, and stem cell factor (or kit ligand) was not detected on CD34+ cells in 48-hour cultures. We also detected upregulation of these alpha subunits by IL-1 alpha and interferon-gamma on leukemic cell lines. Our study showed expression levels for each receptor subunit--including GMR, IL-3R, and c-kit on human bone marrow and peripheral blood cells and leukemic cell lines--and revealed differential regulation of the expression of the receptor subunits.

Gene structures of the alpha subunits of human IL-3 and granulocyte-macrophage colony-stimulating factor receptors: comparison with the cytokine receptor superfamily

Recently, many genes encoding the members of the cytokine receptor superfamily (CRSF), which have common structural features, have been characterized. Analyses on the structures of the genes encoding the alpha subunits of human IL-3 (hIL-3R alpha) and granulocyte-macrophage colony-stimulating factor receptors (hGMR alpha) revealed that they have the structural features common to all members of the CRSF (i.e., conservation of the intron phase pattern as "1-2-1-0-1" rule in the fibronectin type III domains located in extracellular segments of type I cytokine receptor subunits. This finding led us to propose a possible model for gene evolution for the CRSF. We pointed out that the CRSF genes derived from a putative common ancestral gene. In addition to these common features, we found an additional intron that is unique to the IL-3R alpha and the GMR alpha genes. This additional intron suggests that the IL-3R alpha and the GMR alpha genes evolved closely in the evolution process of the CRSF genes. This evidence and results of recent studies on the evolution of mammalian X chromosome make it tempting to speculate that a putative common ancestral gene of the subfamily including IL-3R alpha, GMR alpha, and IL-5R alpha emerged in an autosome at least before the divergence of marsupials and eutherian mammals, early in the 200 million-year history of mammals.

Establishment and characterization of a fibrous histiocytoma cell line (NMSG 10) derived from a malignant fibrous histiocytoma

A fibrous histiocytoma cell line, NMSG 10, was derived from a malignant fibrous histiocytoma (MFH), of human tibia, and its characteristics were examined. MFH was a pleomorphic subtype associated with myxoid and storiform areas. Primary culture revealed a mixture of histiocyte-like cells, fibroblast-like cells and giant cells, but fibroblast-like cells became the major population after several passages in vitro. In addition, NMSG 10 produced a large amount of viscous material which stained with alcian blue and was digested by hyaluronidase. Thus, this viscous material was a single component of glycosaminoglycans: hyaluronic acid (HA). The cells were spindle-shaped with well-developed cytoplasmic organelles and collagenous filaments, and a colloid iron-positive substance was observed in intercellular spaces. In scid mice, the mixed populations of neoplastic cells appeared similar in histology to that of the original tumor. These findings indicated that NMSG 10 expresses the unique properties of MFH, and should therefore be useful in studies on the biological behavior, and especially the presence of HA in MFH.

[Alterations of the brain stem and mid-latency evoked potentials under oxygen-nitrous oxide-sevoflurane anesthesia]

We evaluated the alterations of the brain stem and mid-latency evoked potentials (BAEP and MLAEP) in 10-patients who were scheduled for elective abdominal surgery under oxygen-nitrous oxide-sevoflurane anesthesia. With oxygen 2 l.min-1 and nitrous oxide 4 l.min-1, we measured the latency of BAEP and MLAEP at the end-expired sevoflurane concentrations of 0%, 0.3%, 0.6%, 1.0%, 1.5% and 2.0%, respectively. The latency of BAEP was slightly prolonged with oxygen-nitrous oxide-sevoflurane anesthesia. The latency of MLAEP was markedly prolonged with the increase of sevoflurane concentration, and all waves but Na wave disappeared at the 2.0% sevoflurane concentration.

Regulation of expression of the IL-2 and IL-5 genes and the role of proteins related to nuclear factor of activated T cells

Cyclic adenosine monophosphate (cAMP) inhibits phorbol 12-myristate 13-acetate (PMA)-induced IL-2 production while it inhibits IL-5 production at the transcriptional level in EL-4, a mouse lymphoma line. The -321 to +46 region of the mouse IL-2 promoter is required for activation by PMA and inhibition by cAMP. This promoter region contains several elements that interact with transcription factors, such as nuclear factor of activated T cells (NF-AT), NF-kappa B, AP-1, and octamer. With use of reporter plasmid carrying multiple copies of each element, we found that the construct that contained the NF-AT site was most effective for responding to PMA activation and cAMP inhibition. In electrophoretic mobility shift assay (EMSA), PMA-induced NF-AT binding complex was altered by cAMP. Furthermore, overexpression of the cytoplasmic component of NF-AT abrogated the inhibitory action of cAMP. These results indicate that the NF-AT site is a target of the inhibitory action of cAMP. We have previously reported that the -1200 to +33 region of the mouse IL-5 promoter can mediate transcriptional stimulation by PMA and cAMP in EL-4 cells. Here we identified the element IL-5P, which is required for maximal activation of the IL-5 promoter. We found that this element is homologous to the binding site for NF-AT and interacted with NF-AT-related factors induced by PMA and cAMP. Thus it appears that an NF-AT factor is involved in the regulation of IL-5 gene transcription.

Roles of the cytoplasmic domains of the alpha and beta subunits of human granulocyte-macrophage colony-stimulating factor receptor

The high-affinity and functional granulocyte-macrophage colony-stimulating factor receptor (GMR) is composed of two distinct subunits, alpha and beta; and the cytoplasmic domain of the beta subunit is essential to transduce growth-promoting signals. In contrast to the beta subunit, the role of the alpha subunit is not well characterized. We examined the requirement of the cytoplasmic domain of the alpha subunit and its functional region by deletion analyses. We demonstrated that the cytoplasmic domain of the alpha subunit, especially 29 amino acids residues near the transmembrane domain, was absolutely required for various signaling events including activation of immediate early genes, induction of tyrosine phosphorylation of cellular proteins, and cell growth. We further analyzed the role of the cytoplasmic domain of each subunit by constructing chimeric subunits, designated alpha/beta and beta/alpha, by exchanging cytoplasmic domains of the alpha and beta subunits of human (h) GMR. Reconstituted high-affinity chimeric hGMRs, hGMR(alpha/beta,beta/alpha) and hGMR(alpha/beta,beta), transduced signals at levels similar to the wild type hGMR(alpha,beta) in Ba/F3 cells and in NIH3T3 cells. These observations indicate that the original configuration between the extracellular and the cytoplasmic domains of the hGMR(alpha,beta) subunits is not required and that hGMR(alpha/beta,beta) transduced signals through the cytoplasmic domain of the beta subunit in an oligomeric form, without involvement of the cytoplasmic domain of the alpha subunit. Therefore human granulocyte-macrophage colony-stimulating factor signals are mainly transduced through the beta subunit, and the cytoplasmic domain of the alpha subunit is likely to activate the beta subunit in the normal hGMR.

Adult-onset spinocerebellar dysfunction caused by a mutation in the gene for the alpha-tocopherol-transfer protein

BACKGROUND

Patients with isolated vitamin E deficiency have an impaired ability to incorporate alpha-tocopherol into lipoproteins in the liver and usually have symptoms and signs of spinocerebellar dysfunction before adolescence. Accumulated evidence suggests that the alpha-tocopherol-transfer protein, which is presumed to function in the intracellular transport of alpha-tocopherol, is abnormal in these patients.

METHODS

We studied a patient from an isolated Japanese island who began to have ataxia, dysarthria, and sensory disturbances in the sixth decade of life. His serum vitamin E concentration was low (1.2 micrograms per milliliter [2.8 mumol per liter]). Exons of his gene for the alpha-tocopherol-transfer protein were analyzed by DNA sequencing. We also screened an additional 801 inhabitants of the island for the mutation. Both the normal and mutant alpha-to-copherol-transfer proteins were expressed in COS-7 cells and studied by immunoblot analysis and assay for alpha-tocopherol-transfer activity.

RESULTS

The patient was homozygous for a point mutation that replaces histidine (CAT) with glutamine (CAG) at position 101 of the gene for the alpha-tocopherol-transfer protein. When expressed in COS-7 cells, the missense mutation produced a functionally defective alpha-tocopherol-transfer protein with approximately 11 percent of the transfer activity of the wild-type protein. Of the 801 island inhabitants examined, 21 were heterozygous for the His101Gln mutation. In all affected subjects, including the patient, this mutation cosegregated with an intron-sequence polymorphism. The heterozygotes were phenotypically normal and had serum vitamin E concentrations that were on average 25 percent lower than those of normal subjects (mean [+/- SD], 7.5 +/- 2.2 vs. 10.1 +/- 2.8 micrograms per milliliter [17.4 +/- 5.1 vs. 23.4 +/- 6.5 mumol per liter]; P = 0.002).

CONCLUSIONS

alpha-Tocopherol-transfer protein is a determinant of serum vitamin E concentrations. An abnormality in this protein is a cause of spinocerebellar dysfunction.

Suppression of motor cortical excitability by magnetic stimulation of the cerebellum

EMG responses of the relaxed right thenar muscle evoked by magnetic stimulation over the sensorimotor cortex were suppressed by magnetic conditioning stimulation over the occiput. The optimal interstimulus interval for reduction of the EMG amplitude was 4-6 ms. The optimal conditioning position and induced current direction were 3-4 cm below the inion when the induced current in the center of the figure-8 coil flowed from right to left horizontally. It differed from that for activating the descending motor pathway. We consider this suppression to be due to the inhibition of motor cortex excitability caused by stimulation of the dentato-thalamo-cortical pathway at the dentate nuclei or superior cerebellar peduncle.

[Effect of direct current therapy with chemotherapy in 7,12-dimethylbenz[alpha] anthracene (DMBA)-induced rat mammary cancer]

To improve the quality of life of breast cancer patients with local recurrence, we investigated the effect of direct current therapy in combination with chemotherapy. In this study we chose 3mA of direct current and 1mg/kg of CDDP as optimum based upon a prior experimental study. Rats with mammary cancer induced by 7,12-dimethylbenz [alpha] anthracene (DMBA) were divided into four groups based upon therapeutic methods: direct current therapy alone (Group DC), chemotherapy alone (Group CT), direct current therapy with chemotherapy (Group DC+CT) and no treatment (control). The percentage of tumor area 6 weeks after therapy was 30.8% of the metropeutic size in the Group DC+CT, 46.8% in the Group DC, 107% in the Group CT and 267% in the control (Group DC+CT vs the other groups: p < 0.05). The response rate in the Group DC+CT (100%) was significantly higher than that in the other three groups (chi 2-test, p < 0.05). The platinum concentration ratio of both tumor/serum (p < 0.01) and tumor/kidney (p < 0.05) in the Group DC+CT was significantly higher than that in the Group CT. We conclude that direct current therapy in combination with chemotherapy strongly reduces mammary tumor size of rats.