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Biomedical subjects

K Yamaga

Publications and source records attributed to K Yamaga.

16 recordsLinked to original sources
PubMed1992

Treatment of sleep apnea with prosthetic mandibular advancement (PMA).

Nine males with sleep apnea DOES syndrome and three males with sleep apnea DIMS syndrome were treated with prosthetic mandibular advancement (PMA). The method uses a prosthesis, which is designed to advance the mandible 3-5 mm to prevent upper airway occlusion during sleep. The apnea index in the obstructive-type apnea and the percentage of time spent in obstructive apnea decreased significantly with PMA. Although the apnea index showed merely a tendency to decrease in central apnea (p < 0.1), the percentage of time spent in central apnea decreased significantly with PMA. A marked improvement in sleep structures was observed with PMA; a significant increase was seen in total sleep time, percent slow wave sleep (SWS) and percent rapid eye movement (REM) sleep, and the time spent in intra-sleep awakening decreased remarkably. PMA had excellent effects on snoring, and daytime hypersomnolence was reduced in almost all patients. Moreover, a survey on the therapeutic effects of PMA on sleep apnea syndrome and problems associated with wearing PMA was performed with a questionnaire for the sample of nine DOES patients and an additional 22 patients who were treated over a long time. The therapeutic effects could be maintained without any problems in about 2/3 of these patients. The therapeutic mechanisms of PMA in its reduction of both obstructive and central apnea are discussed.

Adult↗
PubMed1991

Reaction of antibody to mycobacterial 65 kDa heat-shock protein with human chondrocytes.

We report on the reactivities of four monoclonal antibodies generated against mycobacterial proteins to human chondrocytes, cells in cartilage which may be subject to immune attack in rheumatoid arthritis. Only one of the monoclonal antibodies, ML30, which had been shown previously to react with a human homologue to heat-shock protein (hsp), reacted strongly to chondrocytes. By immunocytochemical methods using fixed chondrocytes, ML30 reacted to cytoplasmic constituents in a granular pattern. There were no marked qualitative differences in the staining intensities and patterns of chondrocytes kept at ambient temperatures and those subjected to 42 degrees C heat treatment. No significant staining was observed with normal peripheral blood mononuclear cells. By indirect immunofluorescence, the distribution of ML30 reactive constituents was very low on the cell surface. Reactivities of each of the monoclonal antibodies were tested on frozen sections of cartilage. Significant reactivity was found only with ML30, and the staining was only associated with chondrocytes, not with the cartilage matrix surrounding the cells. These findings may have significance in view of the possibility that an hsp homologue may be a target for inciting or perpetuating the autoimmune process in rheumatoid arthritis.

Antibodies, Monoclonal↗
PubMed1976

Anti-immunoglobulin stimulation of murine lymphocytes. II. Identification of cell surface target molecules and requirements for cross-linkage.

Splenic B cells frliferate in vitro with soluble anti-immunoglobulin (Ig) reagents. To investigate whether the integrity of the anti-Ig molecule is necessary for stimulation and to determine whether cross-linkage of cell surface Ig is required, experiments were done by using F (ab')2 fragments and Fab monomers prepared from anti-MIgM serum. To determine whether antibodies directed against heavy chains would induce cell proliferation, class-specific antisera were prepared and tested. The results showed that cell proliferation was induced by F (ab')2 fragments but not by Fab monomers. In addition, cell proliferation was obtained with monospecific antiserum directed against mu heavy chains but not with antisera directed against alpha- or gamma- chains. Thus cross-linkage of mu heavy chains on the B cell surface is required for soluble anti-Ig-induced proliferation. Further experiments were done to investigate the nature of the age-associated response by comparing membrane immunoglobulin density and class on spleen cells from old and young (2 to 3 months) mice; no differences in surface immunoglobulins were found which would explain the age-associated response to anti-Ig reagents.

Age Factors↗
PubMed1975

Class, amounts and affinities of anti-dinitrophenyl antibodies in chickens. I. Production of 7S and 17S antibodies of equal affinity by intravenous injection of antigen.

Repeated intravenous injections of maximally coupled dinitrophenylated bovine gamma-globulin elicited both 7S and 17S anti-dinitrophenyl antibodies in chickens. Only antibodies of low affinity were produced regardless of the priming dose, the interval between injections, and the number of injections. The 7S and 17S antibodies isolated from invididual animals had identical affinities and heterogeneity indices. The concentrations of antibodies formed were uniformly low despite many injections over a prolonged period. These studies indicate that stimulation by antigen alone may not be sufficient for the induction of predominant 7S antibody formation and for the synthesis of high affinity antibody.

Adsorption↗
PubMed1975

Class, amounts, and affinities of anti-dinitrophenyl antibodies in chickens. II. Production of a restricted population of high affinity 7S antibodies by injection of antigen emulsified in adjuvant.

The response of chickens given a single intramuscular injection of maximally coupled dinitrophenylated-gamma-bovine beta-globulin in either Freund's complete (FCA) or incomplete (FIA) adjuvants was characterized by an initial synthesis of 7S and 17S antibodies followed by the exclusive and persistent production of 7S antibodies. The 17S antibodies were not detected either 3 to 4 weeks after a single injection or after an intravenous boost 16 months later. Injections of low doses of antigen in FCA induced the synthesis of 7S antibodies of high affinity at least by 4 months. Analyses of the Sips plots generated from equilibrium dialysis data indicated that a shift in the distribution of 7S antibody affinities occurred because of the production of a restricted population of high affinity antibodies. The changes in the binding properties of antibody during the immune response from chickens given antigen in FIA were less apparent, although qualitatively similar, to those found in birds given antigen in FCA. Three possibilities were presented to explain the effect of adjuvant on the class and affinity of the antibody: a) the requirement of a second signal for B cell differentiation, b) the presence of subpopulation of B cells, and c) somatic mutation events.

Animals↗
PubMed1974

The effects of electrical stimulation of VL and sub-VL on muscle tonus.

VL and sub-VL were electrically stimulated at 1-mm intervals and the influence on three muscles (anterior tibial muscle, gastrocnemius muscle and soleus muscle) of the contralateral limb was studied by the method of RE-EMG. The effect of VL and sub-VL stimulation was examined on ether clonus as an indicator of hyperactive muscle, especially for spasticity. The results are summarized as follows: 1. Clonus was apparently suppressed by electrical stimulation in an area (F, 10.0 mm; L, 4.0 mm; D, from +2 to -2; there was especially marked suppression of clonus by stimulation in sub-VL. 2. On electrical stimulation of the lateral third of VL, hypertonicity of anterior tibial muscle (T), hypotonicity of gastrocnemius muscle (G), and also hypotonicity of soleus muscle (S), was observed on stimulation of the middle third, T, G, S, and of the medial third, no effect was observed. 3. Electrical stimulation of the anterior part of VL showed T, G, S, and electrical stimulation of the posterior part of VL showed T, G, S.

Animals↗
PubMed1973

The unilateral engram.

It is proposed that the corpus callosum has a major role in the processes of memory; first, by providing access by each hemisphere to memory traces stored in the other, and second, by controlling the formation of memory traces in such a way that they are laid down in only one hemisphere instead of in both. This dual mechanism would have the effect of doubling the mnemonic storage capacity of the brain. Evidence in favor of this hypothesis in briefly reviewed. It is also supported by experiments using electrical excitation of the striate cortex as a conditional stimulus in macaques, and by experiments on maze behavior in the m e species. Experiments with the anterior commissure, on the other hand, show that it, in contrast to the splenium of the corpus callosum, can actually transfer an engram from one hemisphere to the other. Finally, it is shown that the splenium provides an effective path of communication between the central visual system in one hemisphere and the amygdala in the other.

Amygdala↗