Inhibition of glycine currents by dextromethorphan in neurones dissociated from the guinea-pig nucleus tractus solitarii

1. The effect of dextromethorphan (DM) on the current induced by glycine in acutely dissociated nucleus tractus solitarii (NTS) neurones of guinea-pigs was studied by use of the whole-cell patch clamp technique. The effect of DM on gamma-aminobutyric acid (GABA)-induced currents (IGABA) was also examined. 2. DM inhibited 30 microM glycine-induced current (IGly), without affecting the current caused by 30 microM GABA. The action of DM was concentration-dependent, with a maximum effect at 100 microM, and reversible. The half-maximum inhibitory concentration (IC50) of DM was 3.3 microM, about 85 times higher than that of strychnine. 3. DM 3 microM shifted the concentration-response curve for glycine to the right without affecting the maximum value. DM 10 microM shifted the curve even more to the right, although it was not a parallel shift. Strychnine at a concentration of 0.1 microM shifted the curve for glycine in a nearly parallel fashion. 4. The effect of 10 microM DM was slightly weak voltage-dependency, but the lower concentration of DM, 3 microM, inhibited IGly equally at -50 mV and +50 mV. The effect of 3 microM DM on IGly showed no use-dependence. Blockade by strychnine 0.1 microM showed no voltage- or use-dependence. 5. The results indicate that DM inhibits IGly in single neurones of NTS, and further suggest that DM at a low concentration may act on the glycine receptor-ionophore complex, but not on the Cl channel of the complex. However, a relatively high concentration of DM may at least partly affect the Cl- channel of the complex.

A medico-legal approach to the myocardial changes caused by transthoracic direct current countershock

The myocardial damage caused by transthoracic direct current countershock was evaluated serologically and histologically. Countershock energy of between 12 and 240 watt-second (ws) discharge was given to rabbits. Total creatine kinase (total CK) and creatine kinase-MB isozyme (CK-MB) activities in plasma were increased after the countershock, with peak values averaging 5690 IU/L (total CK) and 35 IU/L (CK-MB) within 6 h, whereas the CK-MB activity of a rabbit subjected to countershock in the femoral region was within normal range of less than 3 IU/L. Histologically, epicardial alteration was found in electrode-shaped areas which confined to the superficial epicardium in all rabbits. The heart from rabbits that died within a few minutes after countershock showed epicardial alteration in right and left ventricles, and subendocardial alteration with focal hemorrhage was evident in the left ventricle. Subendocardial necrosis and interstitial edema were also revealed in the left ventricle 72 h after countershock. These myocardial damages appeared in the transthoracic pathway between the electrodes. Thus, we conclude that the myocardial damage caused by countershock is distinguishable from heart disease in terms of the characteristic areas and measuring CK levels.

Studies on the magnitude and the mechanism of cough potentiation by angiotensin-converting enzyme inhibitors in guinea-pigs: involvement of bradykinin in the potentiation

One adverse effect of the angiotensin-converting enzyme (ACE) inhibitors used for treatment of hypertension and congestive heart failure is the production of dry coughs. Imidapril is a new type of ACE inhibitor with a very low incidence of coughs. The magnitude and the mechanism of cough potentiation of imidapril and other ACE inhibitors has been studied in guinea-pigs. In normal guinea-pigs single and repeated dosing of imidapril at 0.1 to 100 mg kg-1 had no effect on capasaicin- or citric acid-induced coughs. Single and repeated dosing of enalapril and captopril at 10 to 30 mg kg-1, respectively, significantly increased the number of capsaicin-induced coughs. Repeated dosing of 1 mg kg-1 enalapril also significantly augmented the capsaicin cough. In bronchitic guinea-pigs imidapril also had no effect on the coughs induced by the two stimulants. Enalapril and captopril significantly increased the number of coughs induced not only by capsaicin but also by citric acid. Lower doses of enalapril were enough to augment the capsaicin-induced coughs, whereas medium to large doses failed to augment the cough irrespective of the protocol of administration. Bradykinin-induced discharges of the vegal afferents from the lower airway were significantly increased by enalaprilat but not by imidaprilat. Capsaicin-induced discharges of the afferents were, on the other hand, significantly depressed by enalaprilat, but not by imidaprilat. Interestingly, enalaprilat depression of the discharges was significantly reversed by Hoe-140, a bradykinin B2 receptor blocker. In guinea-pigs pretreated with a low dose of enalapril, arterial infusion of bradykinin significantly potentiated the coughs induced by capsaicin. The results indicated that imidapril was less potent than enalapril and captopril in potentiating cough responses induced by capsaicin and citric acid in guinea-pigs, and further suggest that bradykinin might be a key substance in the mechanism of the potentiation of coughs associated with ACE inhibitors.

Dexamethasone suppresses mucus production and MUC-2 and MUC-5AC gene expression by NCI-H292 cells

Excessive production of airway mucus is a characteristic feature of many chronic inflammatory lung diseases. Although current pharmacological approaches to excessive mucus production are limited, glucocorticoids appear to be the most effective among a few useful drugs. The exact evidence for the effectiveness of glucocorticoids on mucus production has not been fully elucidated to date. The purpose of this study is to clarify the effect of dexamethasone on mucus production and mucin gene expression in a human pulmonary mucoepidermoid carcinoma cell line (NCI-H292). NCI-H292 cells produced hyaluronidase-resistant high-molecular-weight glycoconjugates (HMWG), which elute in the void volume on Sepharose CL-4B column chromatography. Dexamethasone significantly suppressed the basal production of [3H]glucosamine-or [3H]serine-labeled HMWG in NCI-H292 cells. In Northern blot analysis, dexamethasone attenuated steady-state mRNA levels of MUC-2 and MUC-5AC mucin genes. These data indicate that dexamethasone suppresses the basal production of HMWG and decreases steady-state mRNA levels of mucin genes in airway mucus-producing cancer cells.

Forensic application of organ-specific antigens

A highly sensitive sandwich enzyme immunoassay for organ-specific antigen is described for use in forensic practice. The sandwich enzyme immunoassays for specific antigens to the liver (LSA), the small intestine (sucrase-isomaltase), and the heart (cardiac troponin I) were developed. High levels of antigen could be detected to exist in forensic materials, and it is clearly possible to differentiate between samples from these stabbed organs and those originating from other stabbed organs. In addition, a sandwich enzyme immunoassay for prostate-specific antigen (gamma-seminoprotein, gamma-sm) was developed for sex discrimination of blood and bloodstains. The ratio of gamma-sm to hemoglobin was significantly higher in male adults than in female adults.

[Evaluation of left ventricular diastolic function using gated SPECT with 99mTc-MIBI]

Development of 3 head SPECT system and 99mTc-labeled radiopharmaceuticals enable us to evaluate left ventricular systolic function on the basis of once gated SPECT routine. This study was focused on assessment of left ventricular diastolic function using 99mTc-MIBI gated SPECT data. Twenty nine patients with ischemic heart diseases underwent 99mTc-MIBI gated SPECT and 99mTc-HSAD ventriculographic assessment of left ventricular diastolic function within 1 month. Region of interests (ROI), simultaneously calculating counts per pixel within ROI, were placed over whole myocardium of 16 serial phasic images reconstructed from gated SPECT data, following selection of the central slice within short axial images. Then, 29 patients were classified into 3 patterns of phase count curve (normal, mixed, and delayed relaxation = diastolic dysfunction). Moreover, 1/3 Count Decreasing Fraction (1/3 CDF) was calculated on the same concept as 1/3 FF. The curve pattern showed significant differences between normal and abnormal group divided on the basis of established indices such as 1/3 FF and PFR, and 1/3 CDF has correlations with 1/3 FF (r = 0.61) and PFR (r = 0.58). We concluded that the new parameters drawn from 99mTc-MIBI gated SPECT data might be feasible for evaluation of diastolic function.

Activated eosinophils stimulate phosphatidylcholine secretion in primary culture of rat type II pneumocytes

Activated eosinophils in airway epithelium are involved in the pathogenesis of many airway diseases. We examined whether activated eosinophils influence the secretion of phosphatidylcholine (PC), the predominant component of pulmonary surfactant, in primary culture of rat type II pneumocytes. The eosinophils (10(5) cells/ml) activated by opsonized zymosan (100 micrograms/ml) increased PC secretion from the type II pneumocytes. The increased PC secretion reduced in the presence of both superoxide dismutase (2 units/ml) and catalase (1000 units/ml). These results suggest that activated eosinophils stimulate the secretion of pulmonary surfactant partly through superoxide anions.

Effect of leukotriene D4 on tracheal mucociliary transport velocity in quails

We investigated the effect of leukotriene D4 (LTD4) on tracheal mucociliary transport in quails. Topical application of LTD4 (0.2-2 ng) to tracheal mucosa dose-dependently increased mucociliary transport velocity (MCTV) in 5 or 10 min after application. Forty minutes after application of 2 ng of LTD4, MCTV was decreased to about 84% of that in the control group. Both the transient increase and the subsequent decrease induced by 2 ng of LTD4 were blocked by ONO-1078 (Pranlukast: 4-oxo-8-[4-(4-phenylbutoxy)-benzoylamino]-2-(tetrazol-5-yl)- 4H- 1-benzopyran) (0.03-3 mg/kg, i.m.), a specific leukotriene antagonist. These results suggest that LTD4 possesses a biphasic effect on tracheal mucociliary transport through leukotriene receptors.

Pyridine derivatives stimulate phosphatidylcholine secretion in primary cultures of rat type II pneumocytes

We have examined the effects of pyridine derivatives on phosphatidylcholine secretion in primary cultures of rat type II pneumocytes. Of 12 pyridine derivatives, 4-aminopyridine, 4-dimethylaminopyridine and 4-pyrolidinopyridine had a stimulatory effect on phosphatidylcholine secretion, whereas other derivatives had little effect. The stimulatory effect of 4-aminopyridine was concentration- and time-dependent, and was inhibited by the acetoxymethyl ester of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (3 microM), an intracellular Ca2+ chelator. In addition, the stimulatory effect of 4-aminopyridine was suppressed by W-7(N-(6-aminohexyl)-5-chloro-1-napthalene-sulphonamide)(10 microM), a calmodulin inhibitor, and sphingosine (10 microM) and staurosporine (0-1 microM), protein kinase C inhibitors. These results indicate that several pyridine derivatives stimulate phosphatidylcholine secretion in type II pneumocytes.

Inhalation of phosphoramidon, a neutral endopeptidase inhibitor, induces cough in awake guinea-pigs

In the present study, we explored whether or not a neutral endopeptidase inhibitor provokes cough in awake guinea-pigs. Inhalation of phosphoramidon at a concentration of 10(-6) M did not cause cough, but increasing the concentration to 10(-5) M caused cough with a latency of about 10 to 12 min. Inhalation of enalapril, an angiotensin-converting enzyme inhibitor, did not cause cough, even at high concentrations of 10(-5) M and 10(-4) M. Pretreatment with phosphoramidon (10(-5) M) significantly increased the number of coughs caused by substance P and capsaicin. Capsaicin-induced coughs were more easily produced in bronchitic guinea-pigs than in normal guinea-pigs. However, there was no significant difference in the number of phosphoramidon-induced coughs between normal and bronchitic guinea-pigs. Phosphoramidon-induced coughs were significantly depressed by codeine (20 mg/kg, p.o.) and CP96345 (2 mg/kg, i.v.). The present results provide new evidence for the proposed idea that neutral endopeptidase may regulate the occurrence of cough.

Substance P stimulates the loss of cell-associated high molecular weight glycoconjugates from cultured hamster tracheal epithelial cells through polymorphonuclear leucocytes activation

Abnormal and excessive mucus secretion is a characteristic feature of many chronic inflammatory lung diseases accompanied by the influx of polymorphonuclear leucocytes (PMNs) into the airway and the release of substance P from the peripheral endings of primary sensory neurons. We examined whether PMNs activated by substance P (10 microM) can affect the secretion of high-molecular-weight glycoconjugates (HMWG), which is used as a marker of mucus, from cultured hamster tracheal epithelial cells. We measured both the released and the cell-associated HMWG. Substance P-activated PMNs (10(6) cells/ml) reduced the amount of cell-associated HMWG to 76% of the control level, but did not affect the amount of the released HMWG. The reduction of the amount of cell-associated HMWG was inhibited by ONO-5046, a specific elastase inhibitor. In addition, the HMWG was digested by the activated PMNs. These findings suggested that substance P stimulates the loss of the cell-associated HMWG and degrades the released HMWG from cultured hamster tracheal epithelial cells through PMNs activation.

Sandwich capture enzyme immunoassay for water soluble blood group B substance in secretor saliva

Sandwich capture enzyme immunoassays (EIA I and EIA II) are described. Water soluble B substance was reacted simultaneously with affinity-purified dinitrophenyl goat anti-B IgG and affinity-purified goat anti-B IgG-peroxidase conjugate. The complex formed of B substance, dinitrophenyl IgG and IgG-peroxidase conjugate was trapped onto a polystyrene ball coated with affinity-purified goat anti-dinitrophenyl bovine serum albumin IgG. After washing, peroxidase activity bound to the ball was assayed by fluorometry (the sandwich capture EIA I). In the sandwich capture EIA II, the complex was, after thorough washing, eluted from the ball with dinitrophenyl-L-lysine, and then peroxidase activity in the eluate was assayed. The thorough washing and elution processes improved the sensitivity 3.3-fold, and B substance in saliva samples from type B and AB secretors could be detected 200- to 500-fold more sensitively than hemagglutination inhibition, a method commonly used in forensic practices.

Changes in beta 1- and beta 2-adrenoceptor mRNA levels in alveolar type II cells during cultivation

Alveolar type II cells, the progenitor of type I epithelial cells, synthesize and secrete pulmonary surfactant. In this study, we determined the levels of mRNA for beta 1- and beta 2-adrenoceptor in cultured type II cells using a quantitative RNase protection assay. The mRNA levels for beta 1- and beta 2-adrenoceptors in the freshly isolated cells were 0.51 +/- 0.07 and 1.92 +/- 0.19 amol/microgram total cellular RNA, respectively. In the cells cultured for over 2 days, only beta 1-adrenoceptor mRNA level was remarkably reduced. These results suggest that each mRNA expression may be separately regulated in cultured alveolar type II cells.

Detection of sucrase-isomaltase in stains on a knife by sandwich enzyme immunoassay to determine penetration of the small intestine in a pig model

Using 2 kitchen knives, 2 stab wounds were made into the abdomen of a pig that had been sacrificed under sanctioned processing methods of a meat packing plant. One knife wound penetrated the jejunum and the other, the liver. After leaving the knives at room temperature for a week, the stains on the blades were extracted and subjected to a sandwich enzyme immunoassay to detect the presence of sucrase-isomaltase (sucrase-alpha-dextrinase or SI), a major digestive enzyme of the small intestine. Results of this assay revealed that sufficient SI could be detected only on the knife that had penetrated the jejunum. This animal experiment thus suggests the potential usefulness of an SI assay to identify a weapon that has penetrated the small intestine. Further investigation will be pursued to determine whether this detection method is also valid in humans.

[Cough--diversity and the peripheral mechanisms of production]

The physiology and pharmacology of the cough reflex were reviewed from the perspective that the cough response and its peripheral mechanisms have diversity, taking reported findings together with the results obtained from our own studies. It is clear that there was a remarkable difference in the magnitude of expiration and sound in coughing between the two types of coughs in guinea pigs: one is caused by mechanical irritation to the airway mucosa or citric acid inhalation and the other caused by inhalation of pharmacological agents such as capsaicin and substance P. Four types of stimulation, i.e., mechanical, physicochemical, chemical and pharmacological stimulation, were discussed with respect to the site and the mechanisms of action in the airway. Mechanical stimulants and chemical stimulants such as citric acid seem to act mainly on A delta-fibers. However, it is unclear whether pharmacological agents act on C-fibers to produce cough. As to the difference in distribution of cough receptors in the airway, pharmacological differences were found between coughs caused by mechanical irritation on the laryngeal sites and the site of bifurcation of the trachea. Furthermore, capsaicin, applied by a topical spraying method newly developed by us, produced cough-like forced expiration when it was sprayed around the site of the bifurcation of the trachea. This response was not depressed by codeine, but depressed by ophiopogonin, a Chinese herbal antitussive; mephenesine; and a neurokinin A antagonist. Mechanisms of cough augmentation in bronchitic guinea pigs were also described briefly. In conclusion, the site of action of cough stimulants and the mechanisms of cough production are still controversial. To solve these problems, we need to develop new methods and strategies for studying the cough reflex.

Effects of xanthine derivatives on phosphatidylcholine secretion in primary culture of rat type II pneumocytes

Xanthine derivatives, pentoxifylline, aminophylline, theophylline and chinoin-170, increased phosphatidylcholine secretion in a primary culture of rat type II pneumocytes. However, these xanthines alone had no effect on intracellular cAMP levels in type II pneumocytes. In contrast, terbutaline-induced secretion of phosphatidylcholine was augmented by these xanthines, and the augmentation depended on the increase of cAMP levels. These results suggest that the xanthines induce phosphatidylcholine secretion possibly through cAMP-dependent and cAMP-independent pathways in the primary culture of rat type II pneumocytes.

A sandwich enzyme immunoassay for cardiac troponin I

A sandwich enzyme immunoassay for cardiac troponin I (caTnI) is a description which can identify injuries to the heart. Bovine cTnI was purified from bovine cardiac muscle, then an antibody against cTnI was prepared. We confirmed by immunoblotting that the anti-cTnI antibody reacted only to proteins extracted from the heart and in addition, only to cTnI among them. A mouse monoclonal anti-cTnI IgG-coated polystyrene ball was incubated with cTnI, and subsequently with affinity-purified rabbit anti-cTnI Fab-peroxidase conjugate. Specifically bound peroxidase activity was assayed by fluorometry. The detection limit was 3 fmol (84 ng) per assay. The cross-reaction of the sandwich enzyme immunoassay in regard to proteins from other organs was investigated. A little cross-reaction was recognizable only when proteins from skeletal muscle were in high concentration, but we supposed that this assay could be applied to identify injuries to the heart. We developed a sandwich enzyme immunoassay for bovine cTnI. However, further studies will be aimed at developing a sandwich enzyme immunoassay for human cTnI.

Involvement of protein kinase C in mucus secretion by hamster tracheal epithelial cells in culture

Abnormal regulation of airway mucus secretion may underlie many pulmonary diseases. The exact evidence for the involvement of intracellular signaling mechanisms in mucus secretion has not been fully elucidated to date. The purpose of this study is to clarify the involvement of protein kinase C in the secretion of high-molecular-weight glycoconjugates (HMWG) by hamster tracheal epithelial cells in culture, which elute in the void volume on Sepharose CL-4B column chromatography. HMWG were secreted by the cells cultured on the thick collagen gel, but not on the plastic plate. Two known activators of protein kinase C, 4 beta-phorbol 12 alpha-myristate 13-acetate (PMA) and 1-oleoyl-2-acetyl-sn-glycerol (OAG), stimulated HMWG secretion. In contrast, 4 alpha-phorbol 12,13-didecanoate, a biologically inactive phorbol, did not influence HMWG secretion. D-Sphingosine, an inhibitor of protein kinase C, suppressed the maximal PMA- (10(-8) M) and OAG- (200 microM) stimulated HMWG secretion. PMA induced protein kinase C translocation from cytosol to membrane. These data indicate that protein kinase C is involved in HMWG secretion in hamster tracheal epithelial cells in culture.

[Effects of a novel orally-active antiallergic drug, quinotolast (FK021), on airway clearance]

The effects of a novel antiallergic drug, quinotolast (FK021, sodium 5-(4-oxo-1-phenoxy-4H-quinolizine-3-carboxamido) tetrazolate monohydrate), on airway clearance was studied in comparison with those of tranilast (an orally-active antiallergic drug). FK021 (10 mg/kg, p.o.) did not influence the rabbit airway secretion, whereas tranilast (100 mg/kg, p.o.) caused a slight suppression. Neither FK021 (10(-10)-10(-5) g/ml) nor tranilast (10(-6), 10(-4) g/ml) had any effect on pulmonary surfactant secretion in rat type II pneumocytes. FK021 (10 mg/kg, p.o.) caused a significant increase in the mucociliary transport rate in quails, whereas tranilast (320 mg/kg, p.o.) had no effect. Antitussive effects were examined in normal guinea pigs and guinea pigs made bronchitic by an exposure to SO2. FK021 (10 mg/kg, p.o.) and tranilast (320 mg/kg, p.o.) significantly depressed the cough reflex induced by citric acid in normal animals. FK021 (32 mg/kg, p.o.), but not tranilast (320 mg/kg, p.o.), showed antitussive effects on citric acid-induced cough in bronchitic animals. These results suggest that FK021 may have favorable effects on expectoration and cough reflex observed in the patients with chronic obstructive pulmonary diseases such as asthma.

A highly sensitive sandwich enzyme immunoassay for human liver-specific antigen (LSA) and its forensic application

A highly sensitive and specific sandwich enzyme immunoassay for human liver-specific antigen (LSA) was developed and its forensic application using LSA as a marker for the determination of liver injury were examined. The LSA was purified from human liver by immunoaffinity chromatography. Polystyrene ball coated with affinity-purified rabbit anti-human LSA IgG was incubated with the human LSA and then with affinity-purified anti-human LSA Fab'-horseradish peroxidase conjugate. Peroxidase activity bound to the polystyrene ball was assayed by fluorometry using 3-(4-hydroxyphenyl) propionic acid as a hydrogen donor. The detection limit for human LSA was 0.52 pg per assay. The serum LSA levels determined by this assay in healthy male and female adults were 1.5-1.6 ng/ml and 0.7-1.0 ng/ml, respectively. The recovery of LSA added to 5 microliters and 10 microliters serum samples was estimated to be 53.1-55.5% and 70.6-74.8%, respectively, and no difference in recovery between serum from males and females was observed. LSA antigenic activity in bloodstains containing LSA was detectable after storage for 30 days at room temperature. High levels of LSA were proved to exist in forensic samples taken from stabbed livers, and it was clearly possible to differentiate between samples from stabbed livers and those originating from other stabbed organs. These findings demonstrate that determination of LSA from forensic samples is useful for detecting liver injuries.

Peroxidase labeling of IgMs fragment of ABO blood group specific mouse monoclonal IgM

A method for peroxidase labeling of the monomeric subunit (IgMs) of ABO blood group specific mouse monoclonal IgM is described. IgM was purified from a commercial monoclonal anti-B blood grouping reagent by a combination of salt precipitation, euglobulin precipitation, and gel filtration. IgM was mildly reduced with L-cysteine to yield SH-bearing IgMs. Finally, IgMs was conjugated to horseradish peroxidase, into which SH-reacting maleimide groups had been introduced using N-succinimidyl 6-maleimidohexanoate, through the selective reaction between SH of IgMs and maleimide groups of peroxidase.

[Recommendations for preventing transmission of infection with biohazard in the practice of legal medicine (2). Equipment and practical applications. The Medico-Legal Society of Japan, Committee on Expert Opinions]

In May, 1993, our committee of the Medico-Legal society of Japan published an article entitled "Recommendations for Preventing Transmission of Infection with Biohazard in the Practice of Legal Medicine" in The Japanese Journal of Legal Medicine. Concerning this article, we received a lot of useful comments and opinions from many members of the society, for which we are very grateful. We also received a lot of requests for further information concerning details on the equipment and its practical applications. Since a lot of departments of Legal Medicine at several universities throughout Japan at present are remodelling their facilities in order to be able to perform autopsies, with respect to such circumstances, our committee felt the need to provide information on basic conditions concerning the prevention of transmission of infections with hazards.

Influence of HLA antigens on reproduction among Japanese population: study of haplotypes in 247 families

Although an increased incidence of shared HLA antigens among couples experiencing recurrent spontaneous abortion or infertility has been observed, antigenic effects remain to be clarified. These effects, which are suspected to exist among fertile couples, were examined in this study. A group of 247 healthy Japanese families and their 682 children, whose HLA antigen haplotypes could be determined, were studied. Haplotypes of the fathers were compared with those of the mothers, and the combination of HLA antigens in the A, B, C and DR loci was determined as antigenic patterns against the mother. Patterns inherited by children were examined and deviations of the patterns were studied according to the natural rule that either of the haplotypes should be inherited at equal rates. Lower rates of children with antigens common with those of the mother, which may show a result of reproductive selection, were observed among only the first born children in the A (p < 0.05) and DR loci (p < 0.01), but rates similar to those expected were observed among the second born and later children. Lower rates were also observed in the B and C loci among all children with no significant difference between groups of the children. The necessity of differing antigenic factors in order to achieve pregnancy in the population was shown. Important effects of HLA antigenicity in reproductive failure are suggested.

[Medico-legal studies on detection of organ-specific antigens]

When the organs have been injured, specific antigens pertaining to the organs could be expected to be released into the circulation and/or adhere to the weapons which has inflicted the damage to the organs. We could thus be able to identify the injured organs, if we could detect the antigens specific to the organs in blood of the victim and/or in bloodstains left on the weapons. 1. Liver-specific antigen (LSA). The liver-specific antigen (LSA) was purified from the human liver and was showed to have a molecular mass of 52 kDa and pI of 5.8-5.9. Anti-human LSA antibody only reacted with the liver extract using immuno-dot-blotting technique, and depending on the immunohistochemistry, this antigen was located within the cytoplasm of hepatocytes. The human LSA was proved to be a novel protein, isolated from the human liver, by the NH2-terminal amino acid sequence analysis. Anti-human LSA Fab'-peroxidase conjugate was prepared and a highly sensitive and specific sandwich enzyme immunoassay for human LSA was developed. The detection limit of this assay was 0.52 pg/tube. The LSA levels in the serum and blood of cadavers with liver injuries were markedly increased. These findings suggest that the human LSA will become a useful marker for detecting liver injury. 2. Sucrase-Isomaltase (SI). A sandwich enzyme immunoassay for SI, a dimeric digestive enzyme, was developed using pig as a model animal. SDS-solubilized proteins from the small intestine contained at least 50-fold larger SI than those from the other organs. Significant amount of SI could be detected in small intestinal contents and in stains left on the knife which had been stabbed into the small intestine. These results suggested that SI was a possible forensic marker for small intestinal injuries, although human SI remained to be examined. 3. Cardiac Troponin I (cTnI). The purpose of our study is to identify injuries to the heart from a small amount of blood quickly and accurately by using a sensitive enzyme immunoassay for cardiac troponin I (cTnI), a heart specific protein. Accordingly we purified cTnI from bovine cardiac muscle and prepared the antibody against cTnI in order to develop this assay. We furthermore investigated the usefulness of this antibody by immuno-dot-blotting. As the result, it was confirmed that this antibody reacted against only heart. 4. Dystrophin. The purpose of this work is to develop a method to determine skeletal muscle injuries using muscle-specific substances. Dystrophin was purified from SDS-solubilized bovine skeletal muscle.