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Biomedical subjects

M Kojima

Publications and source records attributed to M Kojima.

At least 847 records · Page 47Linked to original sources

Distribution patterns of microthrombi in disseminated intravascular coagulation.

Distribution of microthrombi in 37 autopsy cases of untreated disseminated intravascular coagulation (DIC) was studied histologically. According to the organs predominantly involved, four patterns of distribution were distinguished: hepatic, hepatorenal, renal, and undetermined. The results suggested that these patterns indicated the course of DIC and the function of Kupffer's cells in the liver, whose role in the course of DIC was evaluated.

Adult↗

Immunoglobulin M antibody against hepatitis B core antigen for the diagnosis of fulminant type B hepatitis.

We attempted to diagnose fulminant type B hepatitis by the hepatitis B core antibody of the immunoglobulin M class. Of 27 consecutive cases of fulminant hepatitis not due to drug-related causes or type A hepatitis, 11 cases with and 9 without hepatitis B surface antigen in the serum revealed a high activity of immunoglobulin M hepatitis B core antibody by radioimmunoassay (S/N ratio 36.3 +/- 20.3). The remaining 7 cases with presumed non-A, non-B hepatitis, as well as the other 4 cases with drug-related causes, did not show any detectable activity (0.99 +/- 0.16). Serums from 30 asymptomatic carriers did not reveal a high activity of immunoglobulin M hepatitis B core antibody (2.1 +/- 1.2), although titers of non-class-specific hepatitis B core antibody were invariably high. On the basis of the results obtained, immunoglobulin M hepatitis B core antibody may be applied for the diagnosis of type B etiology in cases of fulminant hepatitis with or without hepatitis B surface antigen in the serum.

Adolescent↗

Operant behavioral analysis of memory loss in monkeys with prefrontal lesions.

The effects of dorsolateral prefrontal cortical ablation were examined in rhesus monkeys preoperatively trained to perform two versions of an indirect spatial delayed-response task. In one task (DR I), the stimulus keys that signaled the position of the reward were accessible throughout a trial. Thus, the monkeys could orient to the positive side ('rehearse') by continuing to press the correct key during the delay. The other task, DR II, was designed to disrupt bodily orientation and to prevent 'rehearsal'. In this task the monkeys were required to press an extraneous upper key during the delay. After bilateral ablation of the prefrontal cortex, 3 out of the 4 monkeys easily regained preoperative levels of performance on the DR I task, but all subjects were markedly impaired in the DR II task on which they exhibited strong positive preferences. These deficits were ameliorated by eliminating the position biases through training with short delay intervals followed by gradual increments in delay length. Analysis of the location of key presses during each phase of delayed-response trials showed that the monkeys press the correct key in the cue period even when they subsequently made incorrect responses. A consistent finding was that operated monkeys shifted their response to the incorrect key early in the delay period regardless of its duration, whenever the correct side was the nonpreferred side. These results support the idea that delayed-response deficits in monkeys with prefrontal lesions may be due in part to a defect in registering or encoding the correct spatial position in memory rather than to a loss in storage or retrieval processes.

Animals↗

"Waldenström's macroglobulinemia" terminating in immunoblastic sarcoma. A case report.

An autopsy case of 69-year-old man with Waldenström's macroglobulinemia terminating in immunoblastic sarcoma is reported. In the course of this case, the appearance of plasmocytoid lymphocytes was initially observed in peripheral blood smears and bone marrow punctures, but lymph node biopsy and bone marrow aspirations performed in the terminal stage, as well as autopsy, revealed a diffuse monotonous proliferation of immunoblasts in the lymphoreticular tissues. With the immunofluorescence method and PAP method of Taylor,11 IgM kappa type of immunoglobulin was demonstrated in the cytoplasm of the proliferating cells, and the electron microscopic enzyme-labeled antibody technique identified localization of the immunoglobulin in the nuclear envelope and rough endoplasmic reticula of the immunoblasts. The results indicate that the initial appearance of plasmocytoid lymphocytes in this case and its terminal transformation into immunoblastic sarcoma are rare phenomena occurring in a single clone proliferation disorder of B-cell synthesizing IGM kappa immunoglobulins.

Aged↗

Negative inotropic effects of tiapamil (Ro11-1781) and verapamil in rabbit myocardium.

The effects of tiapamil (Ro11-1781) and verapamil on contractility were studied at 1 Hz in isolated rabbit left atrium and right ventricular papillary muscle. The ED50 of tiapamil for the depression of contractility was 33 and 18 times higher than that of verapamil in the former and latter tissue, respectively. In the presence of 100 microM of tiapamil or 10 microM verapamil, the positive staircase phenomenon in papillary muscle was reversed to a negative one. Also, the depression of contractility tended to be less in the first and second responses after a longer interruption of driving stimuli. Both drugs antagonized the inotropic effects of Ca2+ competitively and the pA2 for tiapamil was less than that for verapamil by 1.01. The potency ratios of tiapamil to verapamil for the contractility in this study correspond roughly with those found in clinical use.

Animals↗

Immunohistochemical study on the distribution of serotonin fibers in the spinal cord of the dog.

Distribution of serotonin fibers in the spinal cord of the dog was investigated by means of a modified PAP method; a rabbit anti-serotonin serum prepared in the laboratory of the authors was used in this study. Serotonin fibers were revealed as PAP-positive dark-brown elements displaying dot-like varicosities (0.5--2.0 micrometers in diameter). In the spinal cord of the dog, the distribution of serotonin fibers is extensive. These fibers occur more densely in more caudal segments and are most prominent at the sacrococcygeal level. From the level of the cervical spinal cord to the upper lumbar region, the descending serotonin fibers are located immediately under the pia mater in the ventrolateral portion of the lateral funiculus. In more caudal segments, serotonin fibers are dispersed throughout the ventral and lateral funiculi. These longitudinal en passage-fibers send numerous transverse collaterals to the gray matter. Serotonin fibers are distributed abundantly in the laminae I and III of the posterior column, while only a few fibers are found in the lamina II (substantia gelatinosa). In the intermediate zone, two descending serotonin pathways, i.e., lateral and medial longitudinal bundles, are observed to coincide topographically with the nucleus intermediolateralis at C8(T1)--L3(L4) and the nucleus intermediomedialis at C1--Co respectively. The former is particularly prominent and communicates with the contralateral bundle via commissural bundles at intervals of 300--500 micrometers. The large motoneurons in the anterior column, especially those in the nucleus myorabdoticus lateralis within the cervical and lumbar enlargements, are closely surrounded by fine networks of serotonin fibers and terminals.

Animals↗

Syntheses of 15 alpha- and 15 beta-carboxymethyltestosterone bovine serum albumin conjugates: characteristics of the antisera to testosterone.

Syntheses of 15 alpha- and 15 beta-carboxymethyltestosterone (15 alpha- and 15 beta-CMT) were investigated in order to prepare testosterone-bovine serum albumin conjugates for radioimmunoassays of testosterone. A mixture of 15 alpha- and 15 beta-bis(ethoxycarbonyl)methyl-3 beta-hydroxy-5-androsten-17-one (IIa and IIb) obtained by a reaction of 3 beta-hydroxy-5,15-androstadien-17-one (I) and sodium diethyl malonate was oxidized to afford a mixture of 15 alpha- and 15 beta-bis(ethoxycarbonyl)methyl-4-androstene-3, 17-dione (Va and Vb). After the separation by silica gel chromatography, each epimer obtained was hydrolyzed by acid, followed by decarboxylation, and selective reduction of the 17-ketone to give 15 alpha- and 15 beta-CMT. The antisera, generated in rabbits by immunization with the bovine serum albumin (BSA) conjugates of 15 alpha- and 15 beta-CMT, respectively, exhibited high specificity for testosterone.

Animals↗

Fluoro norcholesterol analogues. Synthesis of 6 beta-(2'-fluoro) ethyl-19-norcholest-5(10)-en-3 beta-ol.

A synthetic route for labelling 6 beta-(2'-fluoro)ethyl-19-norcholest-5(10)-en-3 beta-ol (VII) with fluorine-18 was developed to evaluate the potential utility of VII as an adrenal imaging agent. 6 beta-p-Toluene-sulphonyloxymethyl-19-norcholest-5(10)-en-3 beta-ol acetate (I) was converted to the 6 beta-(2'-hydroxy)ethyl (VI) in a five-step process. The treatment of VI with N-N-diethyl (2-chloro-1,1,2,-trifluoroethyl)amine in methylene chloride and subsequent hydrolysis with base gave the required VII. Iodination of VI with triphenoxymethylphosphonium iodide followed by alkaline hydrolysis gave the 6 beta-(2'-iodo)ethyl (IX) which, on treatment with silver fluoride in acetonitrile, furnished the 6 beta-(2'-fluoro)ethyl (VII). Excellent conversion of the 6-beta-(2'-p-toluenesulphonyloxy)-ethyl (X) into VII was also achieved by heating with potassium fluoride for 2 hr in diethylene glycol in 76% yield, which is a readily applicable method for labelling with fluorine-18.

Chemical Phenomena↗

An unusual papain cleavage of a human IgG1 (lambda) myeloma protein (Mot).

An IgGl (lambda) protein which showed a unique susceptibility towards papain digestion was isolated from the serum of a patient (Mot) with multiple myeloma. The Fab fragments of this protein were degraded rapidly into smaller peptides via an Fb fragment [Gall & D'Eustachio (1972), Biochemistry 11, 4621-4628], which corresponded to the constant domains (Cl-Chl). Structural analysis of the isolated Fab fragment, which consisted of the intact L-chain, a 17,000 and a 5000 mol. wt peptide fragment, indicated that the initial cleavage site was located in the vicinity of the second hypervariable region of the Fd fragment. Examination of the partial amino acid sequences of the Mot H-chain suggested that the variable region of the H-chain may be a hitherto unknown hybrid of subgroups I and III. This particular structure seems to have made the Fab fragment highly susceptible to papain. In the course of the present study, we also found in the papain digests of several human IgG proteins an 'intermediate' 5S fragment, which had previously been reported exclusively for the papain digest of rabbit IgG.

Amino Acid Sequence↗

Tissue Distributions of Chlorogenic Acid and of Enzymes Involved in Its Metabolism in Leaves of Sorghum bicolor.

The tissue distributions of cholorgenic acid, chlorogenic acid oxidase, and three other enzymes involved in the metabolism of this secondary (natural) product have been investigated in leaf-blades of light-grown seedlings of Sorghum bicolor. Cholorogenic acid was found only in epidermal and mesophyll protoplasts isolated from the leaf; 60% of the chlorogenic was contained in the epidermal fraction. Nearly all (90%) of the chlorogenic acid oxidase was found in the mesophyll protoplasts. The bundle-sheath strands, on the other hand, contained no chlorogenic acid and essentially none of the oxidase. Three other enzymes required for the synthesis of chlorogenic acid, but also for other plant products, were found in all three tissue fractions.

Journal Article↗