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Biomedical subjects

M Murakami

Publications and source records attributed to M Murakami.

At least 865 records · Page 48Linked to original sources
PubMed1992

High serum alkaline phosphatase level of meningioma cell origin: case report and review of the literature.

A 13-year-old boy with an anaplastic meningioma at the site of the jugular foramen had an increased serum level of aklaline phosphatase (ALPase) (liver form) in the serum before surgery. Immediately after excision of the tumor, the serum ALPase level decreased dramatically. Histochemical and immunohistochemical examinations revealed ALPase activity (liver form) in the neoplastic cells. This case would be the third with clinical evidence that the increased level of serum ALPase is of neoplastic cell origin from the meningioma. The implications of ALPase in brain tumors are discussed.

Adolescent↗
PubMed1992

Partial purification and characterization of a factor for the enhancement of colony formation in vitro by myeloid progenitor cells.

We have purified a factor, hematopoietic promoting factor (HPF), from porcine kidney extract (PKE), which exhibits a promoting activity on granulocyte/macrophage (GM) colony and burst-forming-unit-erythroid (BFU-E)-derived colony formation by progenitors from murine bone marrow cells in vitro. The addition of HPF resulted in an enhancement of the GM colonies as well as BFU-E-derived colonies, but did not enhance the colony-forming-unit-erythroid (CFU-E)-derived colony formation. HPF was added to the BFU-E cultures together with cytokines, such as recombinant murine interleukin-3 (IL-3), recombinant murine GM colony-stimulating-factor (GM-CSF) and recombinant human G-CSF, which have all been shown to enhance BFU-E growth. The combination of HPF plus these cytokines resulted in an enhancement of benzidine negative colony formation in comparison to the case of each cytokine alone; however, no increase was found on BFU-E colony formation. HPF is able to enhance the granulopoiesis and erythropoiesis in vitro. And the synergistic activity of HPF is significantly affected by the presence of cytokines in the cultures.

Animals↗
PubMed1992

Sympathetic nerve stimulation activates both beta 1- and beta 2-adrenoceptors of SA and AV nodes in anesthetized dog hearts.

We investigated blocking effects of the selective beta 1-adrenoceptor blocker atenolol (0.1-100 micrograms/kg, i.v.), the selective beta 2-adrenoceptor blocker ICI 118,551 (1-1000 micrograms/kg, i.v.) and the combination of the two drugs on positive chronotropic and dromotropic responses to norepinephrine (NE) released by stimulation of the sympathetic nerves in anesthetized, neurally decentralized, open-chest dogs after atropine was given. Stimulation of the intracardiac sympathetic nerves to the SA nodal region or to the AV nodal region selectively increased heart rate or decreased AV conduction time, respectively. ICI 118,551 inhibited the chronotropic or dromotropic response to each stimulation in a dose-dependent manner, but its inhibition of the dromotropic response was less than that of the chronotropic response. Atenolol similarly inhibited either the positive chronotropic or dromotropic response to each stimulation in a dose-related manner. The combination of atenolol and ICI 118,551 attenuated the responses to each stimulation more than atenolol alone. These data indicate that sympathetic nerve stimulation activates both beta 1- and beta 2-adrenoceptors of the SA and AV nodes and that the proportion of beta 2-adrenoceptor-mediated effects on the AV node is less than that on the SA node. These results suggest that neurally released NE in part controls physiological functional cardiac responses mediated through beta 2-adrenoceptors, in addition to the responses predominantly mediated through beta 1-adrenoceptors.

Adrenergic beta-Antagonists↗
PubMed1992

Characteristics of chymotrypsin modified with water-soluble acylating reagents and its peptide synthesis ability in aqueous organic media.

Several kinds of modified chymotrypsin were prepared with water-soluble acylating reagents, and their characteristics after hydrolyzing with unmodified chymotrypsin in aqueous-N,N'-dimethylformamide (DMF) media were compared. It was found that chymotrypsin (Csin), of which a 20% amino group was modified with a benzyloxycarbonyl group (Z(20)Csin), had more favorable characteristics than unmodified chymotrypsin with regard to hydrolytic activity in an aqueous DMF media. We also investigated the Z(20)Csin-catalyzed peptide synthesis in two different solution systems. In the one-layer system containing water and DMF, Z(20)Csin catalyzed the peptide bond formation in a higher yield than that by unmodifide chymotrypsin and enabled a synthetic reaction in even an 80% (v/v) DMF media, in which the hydrolytic reaction could not be carried out. Z(20)Csin catalyzed the condensation between some N-acyl amino acids or peptide derivatives and amino acids in 90% ethylacetate, 90% hexane or 50% benzene. This latter method employs a two-layer system, and the modified enzyme may be able to reduce the number of synthetic steps when preparing acyl peptides.

Acylation↗
PubMed1992

Three-dimensional analysis of the atrophic process of rat seminiferous tubules after estradiol treatment.

Atrophic changes in the basal portion of the seminiferous tubules caused by daily injections of estradiol have been found by scanning electron microscopy disclosed after a digestion technique using collagenase and trypsin. In the control rat, the smooth basal portion of the epithelium was composed of polygonal Sertoli cells and reticularly-arranged ovoidal spermatogonia. After estradiol treatment, there appeared wavy furrows and ridges, and many folded micro-wrinkles in the complicated basal portion of the seminiferous tubules. The wavy furrows and ridges were repeatedly formed and appeared just like a cornice. These structures ran in an orderly manner perpendicular to the longitudinal axis of the tubules. In contrast, many micro-wrinkles ran in parallel to the longitudinal axis. These two structures had a characteristically similar size and orderly arrangement. They are discussed in relation to the mechanism by which the seminiferous tubules shrink by injections of estradiol.

Animals↗
PubMed1992

Effects of diethofencarb on thyroid function and hepatic UDP-glucuronyltransferase activity in rats.

To examine the mechanism and toxicological significance of thyroidal tumor observed slightly in a long-term rat study with diethofencarb (isopropyl 3,4-diethoxycarbanilate), male Sprague-Dawley rats were fed diethofencarb in diets at concentrations of 0, 5,000 or 20,000 ppm for 3 months. Examinations mainly for thyroid functions including thyroid uptake of 125I, serum thyroid hormone and thyroid stimulating hormone (TSH) level, hepatic UDP-glucuronyltransferase (UDP-GT) activity and histopathological examination in thyroid were performed at week 13. Decreases of body weights and food consumptions were observed at and above 5,000 ppm. Under these conditions, decrease of serum free T4 and increase of serum TSH level were observed only at 20,000 ppm, concurrently with liver weight increase at and above 5,000 ppm and increase of hepatic UDP-GT activity at 20,000 ppm. However, no compound related effects were noted in thyroid weight, thyroid uptake of 125I and gross or histopathological examination in thyroid. These results indicate that the administration of diethofencarb leads to an increase in UDP-GT activity and acceleration of thyroid hormone excretion from the liver. The acceleration causes a decrease in serum free T4 level, triggering the feedback mechanism of the pituitary gland, promotion of TSH release and consequently an increase in serum TSH level. Thus, the slightly higher incidence of thyroid follicular cell tumors observed in the chronic and oncogenicity study with non-genotoxic diethofencarb is considered to be caused by these weak pituitary-thyroid hormonal imbalances. The toxicological significance in humans is extremely low according to the well established facts that the chronic TSH stimulating would not induce thyroid tumors in humans and humans may be less sensitive than rats in regard to the response to goitrogenic stimuli.

Animals↗
PubMed1992

Remarkable improvement of growth and developmental retardation in Crohn's disease by parenteral and enteral nutrition therapy.

The patient, an 18-yr-old male (admission ht 153 cm, wt 30 kg), had been suffering from growth arrest and intermittent abdominal pain since he was 13 yr old, which was left untreated. Examinations on admission disclosed almost normal pituitary function, while levels of testosterone and somatomedin C were low. Roentgenological examination revealed extensive skip-stenotic lesions and longitudinal ulcers in the ileum, diagnostic of Crohn's disease. Therapy involving high-caloric parenteral and enteral alimentation resulted in a marked increase in both ht and wt, and improvement in roentgenological and colonoscopical findings. The interrelation between Crohn's disease and malnutrition with reference to some reports in the literature is discussed.

Adolescent↗
PubMed1992

Phototransduction in cones as examined in excised membrane patch.

Phototransduction mechanisms have been so far investigated mostly in rods, whereas those in cones are much less known. In the present experiment, we investigated phototransduction mechanisms in inside-out patches excised from cone outer segments of the carp. Cyclic GMP-activated channels on the patch became light-sensitive when both GTP and Mg2+ were supplied by perfusion. When the channels were activated by a hydrolysis-resistant analogue of cGMP, activities were not suppressed by light even though both GTP and Mg2+ were present. Thus activation of transducin and phosphodiesterase (PDE) were involved in the transduction processes, indicating that phototransduction mechanisms in cones are qualitatively similar to those in rods. In cone patches, however, light responses fully terminated even though ATP was absent, opposing to the report that ATP was indispensable for light response termination in rods. The response termination in the cone patch might result from activation of guanylate cyclase and/or inactivation of PDE. Under the perfusion of GTP together with Mg2+ and 3-isobutyl-1-methyl xanthine, no channel activities were observed, indicating that no guanylate cyclase activity was present in cone patch preparations. Therefore, termination of the light response in the patch might be caused by inactivation of PDE which resulted from inactivation of photopigment and transducin. Based on these observations, differences in light response kinetics between the rod and cone are discussed.

Adenosine Triphosphate↗
PubMed1992

Osmotically inactive space during hyperosmotic stress in the perfused submandibular gland of the rat.

Cell volume changes were measured by an impedance method during hyperosmotic stress in the perfused rat submandibular gland. When the perfusate osmolarity was raised to 484 mosmol, the cell volume decreased and remained at a plateau level (79%). The decrease was smaller than expected from the extracellular fluid osmolarity change. Furthermore, the potassium content of the gland increased by 7% during the hyperosmotic stress. These results suggest that the cell volume changes observed during hyperosmotic stress are affected by the existence of an osmotically inactive space and by an increase in the intracellular solute content.

Animals↗
PubMed1992

Epitope mapping of the nonspecific cross-reacting antigen using various related recombinant proteins expressed in Chinese hamster ovary cells and eight distinct monoclonal antibodies.

Antigenic epitopes of nonspecific cross-reacting antigen (NCA) recognized by 8 different monoclonal antibodies (MAbs) were analyzed in relation to the domain structures of NCA [domains N, I (A1-B1) and M] and CEA [domains N, I (A1-B1), II (A2-B2), III (A3-B3) and M]. We reconstructed cDNAs for NCA-N, NCA-N-I-M, CEA-N, CEA-N-I, CEA-N-I-II, CEA-N-I-II-III-M in a eukaryotic expression vector, pdKCR-dhfr, and expressed them in Chinese Hamster Ovary (CHO) cells. The recombinant proteins were purified by immunoadsorption and gel filtration. By solid-phase enzyme immunoassays, the immunoreactivities of the purified recombinant proteins were tested against eight different MAbs reactive with NCA. All 8 MAbs had been shown to recognize the protein epitopes of the NCA molecule and classified into two groups in terms of the reactivity with NCA and CEA; Group X, 5 clones reactive with both NCA and CEA; and Group Y, 3 clones reactive only with NCA. The epitopes recognized by two of five Group X MAbs were found to be present on the domain N of the NCA molecule as well as of the CEA molecule, and those of the three others were on the domain I (A1-B1) of both molecules, respectively. All three epitopes of Group Y MAbs, which were unique to NCA, were present on the domain I (A1-B1) but not on the domain N of the NCA molecule. The epitope mapping reported here helps form the basis for understanding the relation between the chemical structure and antigenic activities of the NCA molecule and may be useful to study the functions of the NCA molecule, especially those of the respective domains.

Animals↗
PubMed1992

Determination of epitope specificities of a large number of monoclonal antibodies by solid-phase mutual inhibition assays using biotinylated antigen.

A generally applicable method for the determination of the epitope specificities of a large number of monoclonal antibodies (MAbs) is presented. The method is based on the solid-phase mutual inhibition assay using 96-well plates coated with the respective MAbs, competitor MAbs, biotinylated antigen and avidin-peroxidase conjugate. Using carcinoembryonic antigen (CEA) as a model antigen the method was applied to the determination of epitope specificities of anti-CEA MAbs. A constant amount of biotinylated CEA was incubated with a given MAb immobilized on wells of 96-well plates in the presence of increasing amounts of soluble competitor MAbs. The biotinylated CEA bound to the immobilized antibody were then reacted with avidin-peroxidase conjugate and the activity of the bound peroxidase was determined by the use of o-phenylenediamine and hydrogen peroxidase. The method used here alleviates the laborious procedures of labeling all antibodies to be tested and the confusion caused by differential labeling among different MAbs, and is convenient for mapping analysis of many MAbs if the corresponding purified antigen is available.

Animals↗
PubMed1992

Immunoreactivity of recombinant carcinoembryonic antigen proteins expressed in Escherichia coli.

Immunoreactivities of recombinant carcinoembryonic antigen (CEA) proteins expressed in Escherichia coli (E. coli) were analyzed in relation to the CEA domain structure [domains N, I (A1-B1), II (A2-B2), III (A3-B3) and M]. We reconstructed in a prokaryotic expression vector, pUCPL-cI, the cDNAs fro CEA-N, CEA-I, CEA-II, and CEA-III-M. The latter three were expressed as fusion products with bacterial beta-galactosidase. The recombinant proteins were solubilized by sonication in 1% sodium dodecyl sulfate (SDS) and purified by preparative SDS-polyacrylamide gel electrophoresis followed by electroelution. Their molecular weights judged from Western blotting coincided with those calculated from their cDNA sequences, respectively. By solid-phase enzyme immunoassays, the immunoreactivities of the purified recombinant proteins were tested with 21 distinct anti-CEA monoclonal antibodies (MAbs) which had been found to recognize the peptide epitopes of the CEA molecule and to be reactive with the recombinant CEA proteins expressed in Chinese hamster ovary (CHO) cells. Fourteen of the 21 MAbs reacted with the recombinant CEA proteins expressed in E. coli and confirmed the localization of the epitopes identified by using the recombinant CEA proteins expressed in CHO cells. The reactivities of 5 MAbs with the recombinant proteins expressed in E. coli were remarkably low when compared with those of the proteins expressed in CHO cells but also confirmed the localization of the epitopes identified with the recombinant CEA proteins expressed in CHO cells. The remaining 2 MAbs did not react with any recombinant protein expressed in E. coli. These results indicate that the fusion CEA-proteins expressed in E. coli are useful in the localization of the epitopes on the polypeptide chains when they reacted with the MAbs tested. However, one third of the epitopes of CEA peptides may be profoundly affected by the presence of disulfide bonds and/or sugar chains which do not seem to be formed well in E. coli.

Base Sequence↗
PubMed1992

Optical resolution of (+/-)-all-trans-3-hydroxyretinal by use of high-performance liquid chromatography.

Racemic all-trans-3-hydroxyretinal (3-OH-RAL) (1) was converted by a reaction with (-)-camphanic acid chloride (CpCl) into a diastereomixture of camphanates (2a) and (2b) which was separated by preparative high-performance liquid chromatography (HPLC) to give two esters (2a) and (2b) in pure state, respectively. Saponification of (2a) and (2b) independently afforded optically active (3S)- and (3R)-3-OH-RALs (3a) and (3b), respectively, whose absolute structures were determined by circular dichroism (CD) spectra. Racemic 3-OH-RAL was separated to two peaks by HPLC using chiral column (ChiraSpher, Merck). Cochromatography with authentic specimens (3a) and (3b) showed that the peak with a short retention time corresponded to (3R)-isomer and the other to (3S).

Chromatography, High Pressure Liquid↗
PubMed1992

Role of extracellular magnesium in insulin secretion from rat insulinoma cells.

Magnesium (Mg2+) is an abundant intracellular cation that participates in the regulation of the intracellular concentration of ATP. In this study, we examined the relationship between insulin secretion and intracellular free Mg2+ ([Mg2+]i) in a rat-insulinoma cell line (RIN m5F), using a fluorescent dye (Mag-fura-2). KCI, forskolin, and D-glyceraldehyde increased [Mg2+]i and insulin secretion from RIN m5F cells in a dose-dependent fashion. Verapamil, a voltage-dependent Ca2+ channel blocker, inhibited the increase of [Mg2+]i that was evoked by KCI, forskolin, and D-glyceraldehyde. In a Mg(2+)-free buffer, these agents failed to cause an elevation in [Mg2+]i; however, the insulin response to KCI and forskolin was enhanced, compared with that in the presence of Mg2+ (1.25 mM). Our findings suggest that [Mg2+]i is dependent upon extracellular Mg2+, and the influx through the voltage-dependent Ca2+ channel. Mg2+ may competitively inhibit the voltage-dependent Ca2+ channel, which is known to play a role in insulin secretion. An absence of Mg2+ in the extracellular space may result in enhanced insulin secretion. [Mg2+]i may play a role in insulin secretion from RIN m5F cells.

Animals↗
PubMed1992

[Immunohistological investigation of type IV collagen in the basement membrane surrounding the cancer nest (cancer nest membrane) of head and neck squamous cell carcinoma--its relation to frequency of cervical lymph node metastasis].

Lymphoducts and blood vessels exist in the stroma, while none can be detected in the cancer nest itself within cancerous tissue. This explains why metastasis of carcinoma cannot occur without the escape of tumor cells through the basement membrane surrounding the cancer nest into the stroma. Accordingly, observation of the continuity of the basement membrane, what we call the cancer nest membrane, is essential for elucidating the first step of metastasis. Since type IV collagen is the most important structure composing the basement membrane, investigation of the immunohistological localization and continuity of type IV collagen is of value in predicting the metastatic aggressiveness of squamous cell carcinoma. We therefore studied biopsy tissues from the advancing lesion of head and neck squamous cell carcinoma in 95 untreated patients. The tissues were fixed in 85% ethanol and embedded in paraffin, and 5-um thin sections prepared were then immunohistochemically stained for type IV collagen by the ABC method for observation of the continuity status of the cancer nest membrane in relation to metastasis. The basement membranes of normal mucosal epithelium and normal interstitial capillaries were utilized as positive controls, and negative controls were obtained by using PBS in place of the primary antibodies for the immunohistochemical reaction. Membrane discontinuity (breaks or absence) correlated significantly with cervical lymph node metastasis, while intact membrane was associated with a low frequency of cervical lymph node metastasis. There was no obvious relation between the clinical T category and the continuity of the membrane; pN (+) carcinomas with membrane discontinuity included even T1 supraglottic and hypopharyngeal carcinomas, as well as T2 or higher oral mucosal carcinomas and T3 or higher glottic carcinomas, suggesting variation with tumor site. Hypopharyngeal and supraglottic carcinoma was associated with membrane discontinuity and a high incidence of cervical lymph node metastasis. On the other hand, glottic and oral carcinoma more often presented with intact membranes and had a lower incidence of metastasis, although carcinomas in these sites that did present with discontinuity of the membrane were associated with a high incidence of cervical metastasis. Therefore, observation of the continuity of the cancer nest membrane by the expression of type IV collagen may be useful in selecting better specific therapies and determining the necessity of prophylactic neck dissection. A correlation between the degree of tumor differentiation and the continuity of the membrane was also found; well-differentiated tumors with discontinuity of the membrane were frequently associated with cervical lymph node metastasis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

[Immunohistological investigation of epithelial components of adenolymphoma of the parotid gland].

In order to develop a more objective method of evaluating the origin of adenolymphoma, we immunohistochemically investigated the expression of cytokeratins, vimentin, S-100 protein, and alpha-smooth-muscle actin using the avidin-biotin-peroxidase (ABC) method in ethanol-fixed paraffin-embedded specimens from 8 adenolymphomas. Several kinds of monoclonal antibodies which react monospecifically with each subclass of cytokeratins were used. Results were compared with specimens of 8 normal parotid glands by radical neck dissection in patients with other diseases who had not undergone radiotherapy. In the adenolymphoma specimens, basal cells were strongly positive for CK-6, but reactivity of columnar cells was apparently reduced. In contrast, columnar cells were strongly positive for CK-7, but reactivity of basal cells was reduced. In normal parotid gland specimens, CK-7 was also detected in all columnar cells in the ductal system, although some duct cells around the columnar cells, which showed strong CK-6 expression, showed poor CK-7 expression. alpha-smooth-muscle actin was present in myoepithelial cells in normal parotid gland specimens, but not in basal cells of adenolymphoma or of the normal ductal system, which were CK-6-positive. As these characteristic findings were consistently observed in all specimens, the demonstration of CK-6, CK-7, and alpha-smooth-muscle actin may be useful in the recognition and classification of columnar and basal cells. CK-8 was present in both columnar and basal cells of adenolymphoma and of the normal duct, but in the normal parotid gland, acinus cells were also strongly positive for CK-8.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1992

[An immunohistological study of normal parotid gland].

Cytoskeletal proteins from each epithelial component of the parotid gland were studied immunohistologically using monospecific monoclonal antibodies, and we obtained several interesting results: 1) The expression of vimentin, S-100 protein and GFAP were essentially unrecognizable. 2) The expression of alpha-actin was recognized only in myoepithelial cells, and was negative in other tissues. 3) The expression of CK-3, CK-6, CK-7, CK-8 and CK-18 was commonly recognized in both acinal and ductal cells. 4) The expression of CK-13 and CK-19 was recognized in ductal cells, but was negative in acinal cells. 5) We propose that the characteristic cell be referred to as a "duct satellite cell", as it comprises part of the intercalated duct and is sporadically localized around striated and layer ducts. 6) These duct satellite cells express all subclasses of cytokeratin observed in myoepithelial, acinal and ductal cells. 7) The duct satellite cells observed in this study are most likely to correspond to the undifferentiated reserve cells described in "bicellular theory", and we speculate that all epithelial tissues of the parotid gland originate from these cells.

Actins↗