Visualization of newly deposited tau in neurofibrillary tangles and neuropil threads

Neurofibrillary tangles (NFTs) and neuropil threads (NTs), the major hallmark of Alzheimer disease (AD), are composed of the microtubule-associated protein tau that has undergone posttranslational modifications, including deamidation and isomerization on asparaginyl or aspartyl residues. Because such modifications represent protein aging, we generated 2 antibodies, TM4, specific for Asp-387 of tau, and iD387, specific for isoAsp-387 of tau, to investigate the evolution of NFTs and NTs. On Western blots of Sarkosyl-insoluble fractions, TM4 strongly labeled paired helical filament-tau (PHF-tau), whereas iD387 preferentially labeled PHF smear. Thus, it is reasonable to postulate that TM4-labeled tau (unmodified tau species) represents more recent deposition, and iD387-labeled tau (modified tau species) represents earlier deposition. Unexpectedly, TM4 immunostained even highly evolved NFTs, suggesting that deposition of newly produced tau continues until neuronal death. iD387 labeled the whole profile of NFTs up to distal dendritic branches, whereas TM4 staining was localized to particular portions of NFTs in proximal dendrites and neuronal perikarya. In NTs, TM4 preferentially labeled the outer portion, whereas iD387 intensely labeled the core portion. Based on TM4-positive NFT counts and total NFT counts, we speculate that NFTs in the human hippocampus are produced at a constant rate irrespective of the disease stage.     

Oxidative stress and metal content in blood and cerebrospinal fluid of amyotrophic lateral sclerosis patients with and without a Cu, Zn-superoxide dismutase mutation

Hydroxyl radical, ascorbate free radical, superoxide dismutase (SOD) activities, Cu,Zn-SOD protein, Mn-SOD protein, 8-hydroxy-2' -deoxyguanosine (8-OHdG) and metals were compared in red blood cells (RBC), plasma and/or cerebrospinal fluid (CSF) between patients with sporadic amyotrophic lateral sclerosis (SALS), familial ALS (FALS) showing the Leu126Ser mutation in the Cu, Zn-SOD gene and controls. In patients with FALS or SALS, concentrations of hydroxyl radical in blood and ascorbate free radical and 8-OHdG in CSF were higher than control group values, while SOD activities in RBC and CSF were lower. In contrast, Cu, Zn-SOD protein concentrations in RBC were low only in FALS patients. Concentrations of Cu in CSF of SALS patients were higher than in controls. Thus, the pathogenesis of increased oxidative stress differs between SALS patients and FALS patients with a mutant Leu126Ser SOD1 gene.     

A case of recurrent stomach cancer treated with 5-fluorouracil responding to weekly paclitaxel therapy

We report a patient with unresectable stage IV stomach cancer with metastasis to the paraaortic lymph nodes who achieved an effective response to neoajuvant chemotherapy, which allowed curability-B resection, and in whom weekly paclitaxel (TXL) therapy for postoperative recurrence was very effective in improving QOL. The patient was a 65-year-old man. After preoperative PMFE therapy, CEA decreased from 68.1 ng/ml to 0.8 ng/ml, and CA19-9 from 15,000 U/ml to 190 U/ml. The paraaortic lymph nodes disappeared, and stomach wall thickening decreased. The overall response to treatment was evaluated as a partial response (PR). After surgery, the patient was given TS-1, but became unable to take oral medication because of retroperitoneal and lymph node recurrence. Since the cancer appeared to be resistant to 5-fluorouracil (5-FU), the patient was treated by weekly TXL therapy. Increased appetite and weight gain were observed from the middle of the first course of therapy, and CEA decreased from 28.2 ng/ml to 4.9 ng/ml, and CA19-9 from 15,000 U/ml to 2,000 U/ml. Abdominal CT scans demonstrated shrinkage of the tumor. Although the patient died 1 year and 8 months after the initial examination, he was able to take oral medication and maintain good QOL for 10 months after the start of TXL therapy. Only grade 1 side effects (alopecia and leukopenia) were observed throughout the course. These results suggest that TXL therapy is effective also for 5-FU-resistant stomach cancer, and exhibits effects early even in patients in a poor general condition, causing only mild side effects, with early improvements in QOL.     

Cortical processing of tactile language in a postlingually deaf-blind subject

We compared neural activation detected by magnetoencephalography (MEG) during tactile presentation of words and non-words in a postlingually deaf-blind subject and six normal volunteers. The left postcentral gyrus, bilateral inferior frontal gyri, left posterior temporal lobe, right anterior temporal lobe, bilateral middle occipital gyri were activated when tactile words were presented to the right hand of the deaf-blind subject. This set of activated regions was not observed in the normal volunteers, although activation of several combinations of these regions was detected. Positron emission tomography confirmed the location of the MEG-activated areas in the deaf-blind subject. Our results demonstrated that the deaf-blind subject is heavily involved in interpreting tactile language by enhancing cortical activation of cognitive and semantic processing.     

Hyper-processive and slower DNA chain elongation catalysed by DNA polymerase III holoenzyme purified from the dnaE173 mutator mutant of Escherichia coli

BACKGROUND: A strong mutator mutation, dnaE173, leads to a Glu612 --> Lys amino acid change in the alpha subunit of Escherichia coli DNA polymerase III (PolIII) holoenzyme and abolishes the proofreading function of the replicative enzyme without affecting the 3' --> 5' exonuclease activity of the epsilon subunit. The dnaE173 mutator is unique in its ability to induce sequence-substitution mutations, suggesting that an unknown function of the alpha subunit is hampered by the dnaE173 mutation. RESULTS: A PolIII holoenzyme reconstituted from dnaE173 PolIII* (DNA polymerase III holoenzyme lacking the beta clamp subunit) and the beta subunit showed a strong resistance to replication-pausing on the template DNA and readily promoted strand-displacement DNA synthesis. Unlike wild-type PolIII*, dnaE173 PolIII* was able to catalyse highly processive DNA synthesis without the aid of the beta-clamp subunit. The rate of chain elongation by the dnaE173 holoenzyme was reduced to one-third of that determined for the wild-type enzyme. In contrast, an exonuclease-deficient PolIII holoenzyme was vastly prone to pausing, but had the same rate of chain elongation as the wild-type. CONCLUSIONS: The hyper-processivity and slower DNA chain elongation rate of the dnaE173 holoenzyme are distinct effects caused by the dnaE173 mutation and are likely to be involved in the sequence-substitution mutagenesis. A link between the proofreading and chain elongation processes was suggested.     

Self-assessed secondary difficulties among paralytic poliomyelitis and spinal cord injury survivors in Japan

OBJECTIVE: To determine the time course of secondary worsening of difficulties (SWD) experienced by postpolio and spinal cord injury (SCI) subjects in the general population. DESIGN: Self-report survey. SETTING: Multicenter study in general community in Japan. PARTICIPANTS: A total of 662 postpolio and 736 SCI subjects who had had contact with some rehabilitation facility. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Respondents completed a questionnaire about demographic factors, physical complaints, activities of daily living (ADLs), social participation, and a visual analog scale of time course for difficulties (VAST-D) devised for the present study in which the subjects drew a single curve to indicate the lifetime course of disability as they perceived it. RESULTS: Signs of SWD in all extremities of the polio patients and in the upper extremities of the SCI subjects were visually shown by the VAST-D. Additionally, the prevalence of postpolio syndrome and SWD in the SCI group was estimated to be 55.3% and 45.1%, respectively. CONCLUSIONS: SWD was visually shown by the VAST-D in polio and SCI subjects.     

Behavior of male-specific minor histocompatibility antigen in skin and limb transplantation

BACKGROUND: Although the role of male-specific minor histocompatibility antigen H-Y has been increasingly understood in both experimental and clinical organ transplantation, little has been investigated on musculoskeletal tissue transplantation. This study was performed to describe the behavior of male-specific minor histocompatibility H-Y antigen in rat skin and whole limb transplantation. MATERIALS AND METHODS: Using three different strains of inbred rats (Lewis, F344, and Dark Agouti), 75 donor hindlimbs and eighteen skin grafts were isogenically transplanted to the sex-mismatched recipients. Recipients were observed up to 48 weeks postoperatively. Rejection was monitored by the appearance of the skin of the grafted limb and histology. Systemic microchimerism was assessed by polymerase chain reaction using Y-chromosome specific primers. RESULTS: Skin rejection didn't occur in all limb transplant recipients and histology did not show any rejection findings in all components of the limb graft through 48 weeks. Successful functional recovery was expected. Stable and high level of chimerism (>1%) was detected in the lymphoid tissues in nontreated female recipients. Male skin grafts were rejected by Lewis and F344 female recipients within 6 weeks postoperatively. All female skin grafts survived in male recipients. CONCLUSION: Our results suggest that H-Y antigen can induce graft rejection in rat skin graft but causes no rejection reaction in whole limb transplantation. Systemic chimerism may play an important role for acceptance of sex-mismatched limb graft.