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Biomedical subjects

H Gomi

Publications and source records attributed to H Gomi.

At least 73 records · Page 4Linked to original sources
PubMed1992

Auditory brain-stem response in zitter rats with genetic spongiform encephalopathy.

Zitter rats with genetic spongiform encephalopathy and hypomyelination developed an abnormal auditory brain-stem response (ABR) before the appearance of spongy lesions in the central nervous system (CNS). The ABR abnormalities were characterized by a dual peak of wave I, with a longer latency than in normal rats, and decreased or absent waves III and IV. Hypomyelination in both peripheral and central nerves may have been responsible for these abnormalities. The slow negative wave became wide and obscure with aging. These changes accompanied age-dependent progression of spongy changes in the CNS. These findings suggest that at least two mechanisms, one involving hypomyelination and the other causing spongy lesions, are responsible for the brain-stem auditory pathway dysfunction in zitter rats.

Action Potentials↗
PubMed1992

The cerebellum and VOR/OKR learning models.

Although one particular model of the cerebellum, as proposed by Marr and Albus, provides a formal framework for understanding how heterosynaptic plasticity of Purkinje cells might be used for motor learning, the physiological details remain largely an engima. Developments in computational neuroscience and artificial neural networks applied to real control problems are essential to understand fully how workspace errors associated with movement performances can be converted into motor-command errors, and how these errors can then be used as one kind of synaptic input by motor-learning algorithms that are based on biologically plausible rules involving heterosynaptic plasticity. These developments, as well as recent advances in the study of cellular mechanisms of synaptic plasticity, form the basis for the detailed computational models of cerebellar motor learning that have been proposed. These models provide hints toward resolving a long-standing controversy in the oculomotor literature regarding the sites of adaptive changes in the vestibuloocular reflex (VOR) and the optokinetic eye movement response (OKR), and suggest new experiments to elucidate general mechanisms of sensory motor learning.

Animals↗
PubMed1991

An experimental study on selective elimination of beta 2-microglobulin using immunoadsorption method in patients with chronic renal failure.

We studied selective elimination of beta 2-microglobulin (beta 2-m) from plasma of patients with chronic renal failure (CRF) by using immunoadsorption method. Anti-human beta 2-m antibody of rabbit IgG was coated with cellulose beads, which were filled into a small-column. One gm of cellulose beads contains 5.0 mg of the protein of antibody. Five to 7 ml of plasma samples with 40 to 70 mg/l of beta 2-m were passed through the column at 1.0 ml/10 min and each effluent was then collected by 1.0 ml consecutively. Before and after passing through the column, beta 2-m and other plasma proteins were measured. Plasma beta 2-m concentrations in all the effluent fractions after passing through the column were greatly reduced to 1/100. But no other plasma protein components than beta 2-m varied in concentration. Neither Immune complex (IC) nor rabbit IgG was detected in any effluent fraction. These results indicate that selective and effective elimination of beta 2-m from plasma in patients with CRF was possible by using our method. In addition, since neither IC nor rabbit IgG was detected in the effluent, this method was considered to be clinically applicable.

Antigen-Antibody Complex↗
PubMed1991

Soluble IL-2 receptor in patients with primary nephrotic syndrome.

The soluble interleukin-2 receptor (SIL-2R) levels in 46 patients with primary nephrotic syndrome were examined. The values in the nephrotic patients exceeded those in healthy controls (p less than 0.05), and were the same at the nephrotic and non-nephrotic stages. The serum interleukin-2 (IL-2) levels in the nephrotic patients were low and did not correlate with the serum SIL-2R levels. Only at the nephrotic stage were the latter closely correlated with the serum IgG (p less than 0.001) but not with the serum IgA or IgM. The SIL-2R production by phytohemagglutinin stimulated peripheral blood lymphocytes (PBL) in the nephrotic patients was less at the nephrotic and non-nephrotic stages than that in the healthy controls. The IgG production by pokeweed mitogen stimulated PBL was low at the nephrotic stage but not at the non-nephrotic stage. Based on these findings, it is suggested that SIL-2R determinations should prove useful in clarifying the relationship between cellular and humoral immunological disorders in nephrotic syndrome.

Adult↗
PubMed1990

The gene sequence and some properties of protein H. A novel IgG-binding protein.

The gene for protein H, a novel bacterial cell wall protein with specific affinity for human IgG Fc, was cloned from a group A Streptococcus and expressed in Escherichia coli. Recombinant E. coli cells produced two forms of a human IgG Fc-binding protein, one with an apparent Mr of 42 kDa in a periplasmic fraction and the other with an apparent Mr of 45 kDa in a mixed fraction of cytoplasms and membranes. Both 42-kDa and 45-kDa protein preparations similarly bound to human IgG1 to IgG4, human IgG Fc, and rabbit IgG, but not to IgG of mouse, rat, bovine, sheep, goat, and human IgA, IgD, IgE, and IgM. The complete nucleotide sequence of the cloned 1.8-kb DNA fragment was determined. An open reading frame encoded a hypothetical protein of 376 amino acid residues (Mr = 42,498). The N-terminal amino acid sequence, consisting of 41 residues, which was removed post-translationally had typical characteristics of Gram-positive bacterial signal peptides. Thus, the mature form of protein H was suggested to consist of 335 residues (Mr = 38,162). There were 3 repeated sequences consisting of 42 residues that were highly homologous to those of protein Arp, an IgA-binding streptococcal cell wall protein, and streptococcal M6 and M24 proteins. The C-terminal amino acid sequence consisting of 93 residues, directly following the repeated sequences, was also highly homologous to that of M6 and M24 proteins. No sequence homology was found between protein H and protein A or protein G, two other IgG-binding bacterial cell wall proteins.

Amino Acid Sequence↗
PubMed1990

Edematous changes in the central nervous system of zitter rats with genetic spongiform encephalopathy.

The pathogenesis of progressive spongy degeneration in zitter rats with genetic spongiform encephalopathy was examined histopathologically and biochemically in the context of edematous change in the central nervous system (CNS). Histopathological studies revealed that vacuolation in the CNS of zitter rats progressed with aging and the severity of spongy degeneration was markedly divergent in different areas in the CNS. Edematous change was confirmed by a consistently higher water content in the brain of zitter rats than in that of normal SD/J rats at all ages. Furthermore, a close relationship between spongy degeneration and edematous change in the CNS was demonstrated by regional measurement of specific gravity (SPGR) of brain tissues and quantification of the spongy degeneration by computer-image analysis. The brain regions with lighter SPGR were more severely affected by spongy degeneration. These results suggest that edematous change is related to the pathogenesis of spongy degeneration in the CNS of the zitter rat.

Animals↗
PubMed1990

Effects of low protein diet in puromycin aminonucleoside-induced nephrotic rats.

Wistar rats were injected with puromycin aminonucleoside (PAN) to induce massive proteinuria and were raised on a low protein diet to determine whether the urinary protein excretion might be reduced. Although PAN nephrotic rats fed with a normal protein diet containing 20% protein (group A) did not show any reduction of their urinary protein excretion, PAN rats fed with a low protein diet containing 6% protein (group B) revealed a marked reduction at day 9 of the present study in comparison with group A. The total serum protein levels were low in groups A and B as compared to group C, the non-treated control. However, group A recovered to normal levels at day 13. In terms of the absolute amount of oral protein intake, marked differences were observed between groups B and C, but little difference was observed between groups A and C. The body weight in all three groups was decreased at 8 days after the start of this study. The serum levels of creatinine were elevated to 1.1 +/- 0.3 mg/dl and 1.0 +/- 0.2 mg/dl in groups A and B, respectively, on day 7, but abruptly recovered to normal levels by day 12. These data indicate that the decreased urinary protein excretion in group B might be dependent on the total protein volume intake, and not on the renal function nor serum levels of total protein.

Animals↗
PubMed1990

Urinary N-acetyl-beta-D-glucosaminidase isoenzyme activity as measured by fast protein liquid chromatography in patients with nephrotic syndrome.

Exactly why N-acetyl-beta-D-glucosaminidase (NAG) excretion is increased in patients with nephrotic syndrome with glomerular lesions is poorly understood. Glomeruli contain less NAG than do proximal tubules. In this study, we have tried to measure the NAG isoenzymes automatically by use of the recently developed fast protein liquid chromatography (FPLC) system, followed by column chromatography on DEAE cellulose (Mono Q). Three isoenzyme peaks--B, I + II, and A--were observed for urine from both healthy subjects and nephrotic patients. The B isoenzyme usually constituted about 10% of the total NAG in healthy controls, 30% in nephrotic patients. In contrast, the proportion of the A isoenzyme was inversely related to that of the B isoenzyme when healthy controls and nephrotic patients were compared. Our system for measuring NAG isoenzymes is reproducible and fast, and it should be useful in further studies.

Acetylglucosaminidase↗
PubMed1987

Major histocompatibility complex-restricted augmenting T cells induced by in vitro cultivation of antigen-primed T cells. A new parallelism between suppressor and augmenting circuits.

In vitro cultivation of primed T cells with antigen resulted in the induction of a regulatory T cell that nonspecifically augmented the in vitro antibody responses of H-2-compatible T and B cells. This T cell, designated as the augmenting T cell (Ta), was unable to help B cells by itself but enhanced the antibody response of B cells to several multitudes only when conventional helper T (Th) cells or cloned Th cells from the same H-2 haplotype coexisted. Ta was radioresistant and belonged to Lyt-1+, 2-, L3T4+, I-J- T cell lineage. Ta exhibited interesting H-2-restricted activities: when primed T cells from (A X B) F1 were cultured with the antigen in the presence of parent A type antigen-presenting cells, the induced Ta was able to augment the antibody response of (A x B) F1 B cells in the presence of Th cells from F1----A but not from F1----B radiation bone marrow chimeras. This indicates that the induction of Ta in an F1 T cell population is dependent on the H-2 haplotype of antigen-presenting cells during in vitro cultivation. The restriction specificity of the established Ta is, however, not directed to the class II antigen itself but to the restriction specificity of Th cells that recognize class II antigen. In support of this is the fact that the elimination of A-restricted Th cells during cultivation by treatment with anti-I-J mAb, which is known to react with H-2-restricted Th cells, resulted in failure of induction of Ta cells having the augmenting activity for the A-restricted response.

Animals↗
PubMed1987

Efficient cleavage by alpha-thrombin of a recombinant fused protein which contains insulin-like growth factor I.

The gene for insulin-like growth factor I (IGF-I) was constructed from chemically synthesized deoxyoligonucleotides and expressed in Escherichia coli, under the control of a trp promoter, as a set of fusion proteins which were connected with a portion of human growth hormone through the recognition sequence for a sequence-specific protease, either blood coagulation factor Xa or alpha-thrombin. Upon induction with 3-indoleacrylic acid, fusion proteins accumulated with a yield of 10-30% of the total protein. A fusion protein connected through a tetradecapeptide (Asp-Asp-Pro-Pro-Thr-Val-Glu-Leu-Gln-Gly-Leu-Val-Pro-Arg) was efficiently and correctly cleaved by alpha-thrombin, and the purified IGF-I possessed somatomedin-like activity, as determined by the enhancement of sulfation of glycosaminoglycans in cultured costal chondrocytes from rabbits.

Biological Assay↗
PubMed1987

[Present status of high LET radiation therapy--fast neutron radiotherapy in Japan].

More than 1,900 patients of advanced and inoperable malignant tumor were treated with fast neutron radiotherapy using 30 MeV (d-Be) and 14 MeV (d-Be) beams at NIRS and IMS between 1975 and 1986. Protocols were largely nonrandomized. Some results have been obtained: 1) results with mixed beam studies for advanced squamous cell carcinoma of the uterine cervix have been equivocal compared with the photon controls. 2) some trends of local control have been observed in the trial of esophageal cancer, early cases of adenocarcinoma of the lung and malignant melanoma. 3) significant better results were observed in the pancoast type lung cancer and osteo sarcoma which was treated by the systemic multimodal treatment. It is concluded that neutrons are efficacious for certain specific tumor types owing to some biological effects, however the problem of inferior dose distribution was the weakness of neutron therapy at present.

Bone Neoplasms↗
PubMed1987

[The integrated score of prognostic factors with regard to the recurrence of cervical carcinoma].

Eighty-nine patients with carcinoma of the cervix received radical radiation therapy from May 1981 through 1983 at the hospital of the National Institute of Radiological Sciences. After a 2 to 4 year follow-up, primary cancer was found to be controlled in 59 patients, a recurrence was noted in 16 patients but 12 patients had died without precise information concerning recurrence. We examined the correlation between recurrence and seven prognostic factors. Among these factors, the tumor volume, age, and the red blood corpuscle sedimentation rate showed a relatively strong correlation. A multivariable analysis (quantification methods II) was undertaken in order to integrate these prognostic factors and the score that was calculated from this analysis showed a strong correlation to local control. We believe that this score can be used for predicting recurrences and can be applied to the selection of patients for new treatments like hyperthermia or high LET irradiation.

Adenocarcinoma↗