Tumor necrosis factor-beta gene expression and its relationship to the clinical features and histopathogenesis of peripheral T-cell lymphomas

We investigated the levels of tumor necrosis factor-beta (TNF-beta) mRNA in the tumorous tissues of a series of 18 patients with peripheral T-cell lymphomas (PTCL), to assess the contribution of the expression of this gene to the features of the disease. Total RNA, extracted from diagnostic tissue specimens, was subjected to semiquantitative analysis by reverse transcription-coupled polymerase chain reaction (RT-PCR). The level of TNF-beta mRNA was semiquantified against that in MT-2 cells, a line of human T cells infected with human T cell leukemia virus type I (HTLV-I). Expression of TNF-beta in neoplastic T-cells was confirmed by immunohistochemistry. The extent of TNF-beta gene expression was correlated with the histopathological features of neovascularization. There was also a relationship between the extent of TNF-beta gene expression and the presence of B-symptoms. Results suggest that TNF-beta produced by neoplastic T-cells influences clinical features and is involved in histopathogenesis of PTCL.

[Apolipoprotein A I-C III-A IV deficiency]

The genes coding for apolipoprotein A-I, apo C-III, A-IV are located on the long arm of chromosome 11. The three genes are tandemly organized. Familial apolipoprotein A-I, C-III, A-IV deficiency was reported. The homozygous proband had extremely low HDL-cholesterol and premature coronary atherosclerosis. Analysis of the abnormal allele revealed the complete deletion of the apo A-I, C-III, A-IV genes. The deletion occurred in areas of repetitive DNA sequence. Familial apolipoprotein A-I, C-III deficiency has been shown to be due to the DNA inversion between the exon 4 of apo A-I and the first intron of apo C-III. The homozygous proband has HDL, deficiency and severe atherosclerosis. RFLP in this gene lesion has been reported and is closely related with the decrease of HDL, hypertriglyceridemia and coronary atherosclerosis. The elucidation of the relation between one particular allele in the lesion of apo A-I, C-III, A-IV gene cluster with lipoprotein metabolism and coronary atherosclerosis will require further determination of the precise nucleotide sequence variation.

Ontogeny of protein kinase C in the rat hippocampus: an autoradiographic study with [3H]phorbol 12,13-dibutyrate

The ontogeny of protein kinase C (PKC) in the hippocampus was studied in 1-week-, 4-week-, and 3-month-old Wistar rats with in vitro receptor autoradiography using [3H]phorbol 12,13-dibutyrate ([3H]PDBu). The developmental pattern of [3H]PDBu binding varied within hippocampal subregions. [3H]PDBu binding in stratum oriens of the CA1 and CA3 sectors and stratum lucidum of the CA3 sector increased to adult levels by 4 weeks. In strata moleculare and granulosum of the dentate gyrus, the binding reached peak values at 4 weeks but declined at 3 months. Interestingly, in stratum lacunosum-moleculare of the CA1 sector, the [3H]PDBu binding activity was the highest at 1 week. There were constant binding activities in stratum radiatum of the CA1 and CA3 sectors and the dentate hilus during the postnatal development. These findings may provide evidence that PKC has a distinct role in different subregions of the hippocampus during postnatal development.

Sequence homology of Chinese hamster metallothionein genes I and II to those of the mouse and rat, and their amplification in Cd-resistant cells

The metallothionein (MT) I and II genes were isolated from Chinese hamster cells and sequenced. The MT-II gene is located about 6 kb upstream of the MT-I gene and their arrangement is similar to those of the mouse and rat MT genes. The sequence of the Chinese hamster MT-I gene is highly homologous to those of the mouse and rat, particularly in their promoter regions of MT-I. However, the promoter region of MT-II has less homology with those of the mouse and rat due t to insertions and deletions. The MT-I and MT-II genes were equally amplified 4-8-times in the Cd-resistant Chinese hamster cells, suggesting that both genes are included in the same amplification unit. Cytogenetic analysis of Cd-resistant cells by in situ hybridization showed that they are randomly integrated into multiple sites on the chromosomes.

Astroglial and microglial reactions in the gerbil hippocampus with induced ischemic tolerance

Preconditioning of the brain with sublethal ischemia protects against neuronal damage following subsequent longer periods of ischemia (ischemic tolerance). In this study, we investigated astroglial and microglial reactions in the hippocampus following ischemia in a gerbil model of ischemic tolerance. Two minutes of forebrain ischemia (preconditioning ischemia) or sham operation was followed by 3 min of ischemia (second ischemia) 3 days later. The brains were perfusion-fixed after 4 h, 1 day, 2 days, and 7 days. Paraffin sections were used for the visualization of astrocytes by immunostaining against glial fibrillary acidic protein (GFAP) and for the visualization of microglia by histochemical staining with isolectin-B4 from Griffonia simplicifolia. The preconditioning ischemia induced a moderate increase in astroglial and microglial staining. Two days after the second ischemia, GFAP staining further increased in astrocytes in the hippocampus with ischemic tolerance. In the CA1 region of the hippocampus without ischemic tolerance, in contrast, microglial activation with increased staining and morphological changes was pronounced. After 7 days, neuronal destruction resulted in the CA1 region without tolerance, where hypertrophic reactive astroglia and reactive microglia with phagocytic transformation accumulated intensely. However, the ischemic preconditioning prevented the CA1 neuronal damage and the activation of microglia was subsiding after 7 days. Thus, activation of glial cells occurred in a graded fashion in response to different degrees of neuronal injury. Astroglial but not microglial activation may have implications in neuronal survival in ischemic tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoradiographic distribution of neurotransmitter and second messenger system receptors in animal brains

We investigated species difference in binding of major neurotransmitters and intracellular second messengers in the gerbil brain and the rat brain using receptor autoradiography. [3H]Phorbol 12,13-dibutyrate (PDBu), [3H]inositol 1,4,5-trisphosphate (IP3), [3H]PN200-110, [3H]muscimol, [3H]MK-801, [3H]cyclohexyladenosine (CHA),and [3H]quinuclidinyl benzilate (QNB) were used to label protein kinase C, IP3 receptor, L-type calcium channel, gamma-aminobutyric acidA (GABAA) receptor, N-methyl-D-aspartate (NMDA) receptor, adenosine A1 receptor, and muscarinic cholinergic receptor, respectively. Autoradiographic distributions of the bindings of most neurotransmitters and second messengers were particularly found in the limbic system and basal ganglia in both gerbil and rat brains. However, marked differences in these bindings between the gerbil brain and the rat brain were also recognized in the above regions. In particular, among 7 ligands used, the gerbil had high [3H]PDBu and [3H]CHA binding sites throughout the brain compared to those in the rat brain except for a few areas. By contrast, the rat exhibited high [3H]MK-801 binding sites in various brain regions, as compared with the gerbil brain. Thus, the gerbil differ from the rat with respect to the binding sites of major second messengers and neurotransmitters in the brain. The results may help better elucidate the relationship or species difference between gerbils and rats for neuronal function and behavioral pharmacology.

Inhibition of serine proteases of the blood coagulation system by squash family protease inhibitors

Squash family inhibitors are the smallest protein serine protease inhibitors, being composed of approximately 30 amino acid residues. We isolated 8 squash family inhibitors from the seeds of bitter gourd, squash, gourd and luffa and examined their effect on serine proteases of the blood coagulation system. Five of them prolonged the activated partial thromboplastin time of human plasma to various extents, but three did not. Only Momordica charantia (bitter gourd) trypsin inhibitor-II prolonged the prothrombin time of human plasma. All inhibitors inhibited the amidolytic activities of factor XIIa, plasma kallikrein, factor Xa, but did not inhibit significantly those of factor XIa, factor IXa, factor VIIa, and thrombin. Ki values for factor XIIa, plasma kallikrein, and factor Xa were in the order of 10(-6)-10(-9), 10(-4)-10(-5), and 10(-4)-10(-6)M, respectively. The prolongation of the activated partial thromboplastin time by inhibitors appeared to correspond to their inhibitory potencies for factor XIIa. Momordica charantia trypsin inhibitor-II, which has the strongest inhibitory potency toward the amidolytic activity of factor Xa, with a Ki value 10-100 times smaller than those of other inhibitors, inhibited the activation of factor X by factor VIIa-tissue factor complex or factor IXa, while others did not.

Carrier-mediated transport of H1-antagonist at the blood-brain barrier: a common transport system of H1-antagonists and lipophilic basic drugs

The blood-brain barrier (BBB) transport system for H1-antagonists was studied using primary cultured bovine brain capillary endothelial cells (BCEC). The uptake of [3H]mepyramine was inhibited by various H1-antagonists. Ketotifen competitively inhibited [3H]mepyramine uptake with an inhibition constant (Ki) of 46.8 microM. Lipophilic basic drugs such as propranolol, lidocaine and imipramine significantly inhibited [3H]mepyramine uptake. In particular, propranolol inhibited [3H]mepyramine uptake competitively at an inhibition constant (Ki) of 51.1 microM. Moreover, in ATP-depleted BCEC, [3H]mepyramine uptake was stimulated by preloading with H1-antagonists and lipophilic basic drugs. These results indicated that H1-antagonists are transported across the BBB via a carrier-mediated transport system common to lipophilic basic drugs.

Antibacterial and antifungal sulfated alkane and alkenes from the hepatopancreas of the ascidian Halocynthia roretzi

Four new antibacterial and antifungal sulfates, 2,6-dimethylheptyl sulfate [1], (4Z,7Z)-4,7-decadienyl sulfate [2], (4Z,7E)-4,7-decadienyl sulfate [3], and (3Z,6Z)-3,6,9-decatrienyl sulfate [4], have been isolated from the hepatopancreas of the ascidian Halocynthia roretzi. The structures were determined by spectral analysis.

Partial characterization of larval antigens of Strongyloides papillosus by western blot analysis

Western blotting was used to analyse the antigens in extracts of adult and infective larvae (SIL) of Strongyloides papillosus with serum of infected rabbits. Several proteins in both the extracts reacted with immunoglobulin G in the serum. A protein of about 16 kDa in the extract of SIL showed an especially strong reaction. No cross-reaction was observed among proteins in the extracts of adult worms of such cattle helminths as Fasciola gigantica, Homalogaster paloniae, Trichuris discolor and Setaria digitata to S. papillosus-infected rabbit serum. The cuticle of the worms and substances in the worm tracks showed positive reaction with the immunoperoxidase test on SIL with the serum.

Clinical usefulness of CYFRA assay in diagnosing lung cancer: measurement of serum cytokeratin fragment

We evaluated the diagnostic usefulness of measurement of the soluble cytokeratin 19 fragment, a new tumor marker, in 391 patients with lung cancer and in 424 patients with benign lung diseases. Serum concentrations of cytokeratin 19 fragment were measured by a sandwich ELISA (CYFRA). The cut-off value was defined as 3.5 ng/ml, which is associated with a specificity of 85% for benign lung diseases. CYFRA had a high sensitivity (57.5%) in all subjects with lung carcinoma, and had a higher sensitivity for squamous cell carcinoma (73.1%, n = 141) than squamous cell carcinoma-related antigen (61.0%). CYFRA was associated with a relatively high sensitivity (42.1%) in early-stage squamous cell carcinoma (stage I, based on the classification of the Japan Lung Cancer Society), but the CYFRA titer was higher in advanced squamous cell carcinoma than in early-stage squamous cell carcinoma. Our findings suggest that CYFRA is potentially useful for diagnosis and monitoring of lung carcinoma, especially for squamous cell carcinoma.

[Application of whole layer core biopsy of bladder wall to paravesical tumor]

We have reported the usefulness of percutaneous or transurethral whole layer core biopsy (WLCB) of bladder wall for staging of invasive bladder cancer. We have applied WLCB to 3 cases of paravesical tumor with good results. The first case was in a 3-year-old boy suspected of retrovesical sarcoma. Percutaneous WLCB revealed an inflammatory tumor of the Douglas cavity which was probably caused by perforation of appendix. The tumor disappeared by antibiotics alone. The second case was in a 37-year-old female with retrovesical tumor suspected to be ovarial cancer because of the high value of CA19-9 and CA125. Transurethral WLCB showed invasion of endometriosis to bladder muscle layer. The third case was in a 75-year-old female diagnosed by transurethral WLCB as sigmoid colon cancer invading until the deep bladder muscle layer. Cold cup punch biopsy was not informative in these 3 cases. Percutaneous or transurethral WLCB is safe and easy to perform, and is a technique recommended for diagnosis of pathology and bladder invasion of paravesical tumor.

Effects of vinconate and pentobarbital against postischemic alterations in spirodecanone binding sites in the gerbil brain

We investigated the effects of vinconate and pentobarbital against the alterations in spirodecanone binding in the gerbil striatum and hippocampus 5 h and 7 days after 10 min of cerebral ischemia, using receptor autoradiography. Vinconate and pentobarbital were given intraperitoneally 10 and 30 min prior to ischemic insult, respectively. The spirodecanone binding in vehicle-treated gerbils subjected to ischemia was unchanged in the brain 5 h after recirculation, compared with that in sham-operated animals. Seven days after ischemia, a significant elevation in the spirodecanone binding was observed in the striatum and the stratum radiatum of the hippocampal CA1 sector and the hippocampal CA3 sector of the vehicle-treated animals. Other regions showed no significant change in the binding. Vinconate and pentobarbital showed no significant change in the striatum and hippocampus 5 h after ischemia. However, the administration of vinconate inhibited a significant elevation in the spirodecanone binding in the lateral striatum and the stratum radiatum of hippocampal CA1 sector 7 days after ischemia. Pentobarbital also prevented a significant elevation only in the lateral striatum. A histological study revealed that cerebral ischemia caused severe neuronal damage in the lateral striatum and hippocampal CA1 and CA3 sectors. However, ischemic neuronal damage was not observed in the dentate gyrus. An immunohistochemical study also showed that numerous reactive astrocytes were evident in the hippocampus, particularly in the hippocampal CA1 sector, 7 days after ischemia. The present study demonstrates that cerebral ischemia can cause a conspicuous elevation in spirodecanone binding in the striatum and hippocampus. They also suggest that the postischemic elevation in the spirodecanone binding is partly prevented by treatment with vinconate and pentobarbital. These results suggest that the postischemic elevation in spirodecanone binding sites may reflect expression of reactive astrocytes.

Serial water changes in human skeletal muscles on exercise studied with proton magnetic resonance spectroscopy and imaging

In vivo 1H-magnetic resonance imaging (MRI) enabled us to study the distribution of water in living tissues and to document changes in human skeletal muscles during physical exercise. The purpose of the present study was to determine the total muscle water changes after exercise using water in 1H-MR spectroscopy and to compare these changes to the signal intensity change on T2*-weighted images and/or to the T2 value change. Seven young male volunteers were positioned in a 1.5 T Philips MR imaging system. They were then asked to dorsiflex their ankle joint against a 2 kg weight once every 2 seconds for 2 minutes. The peak height of water declined according to the clearance curve after exercise in all seven cases with the 1H-MRS similar to the signal intensity. The increasing rate at peak height of total muscle water exceeded both the signal intensity and the T2 value because the water peak height on the 1H-MRS included the extracellular water. In addition, we measured the changes in signal intensity in both calf muscles after walking race exercise. The time intensity curves were used to draw a clearance curve for each muscle group after exercise. It was possible to discern which muscle was used most from the T2*-weighted image that was obtained once after exercise.

Effects of pancreatic transplantation on osteopenia in streptozotocin-induced non-insulin-dependent diabetic rats

The effect of pancreatic transplantation on mineral homeostasis and the histomorphometric changes were studied in streptozotocin (STZ)-induced non-insulin-dependent diabetic rat. Although the fasting blood-glucose levels in diabetic rat were similar to those in controls, intravenous glucose tolerance tests (ivGTT) showed diabetic patterns in the diabetic rat. Serum ALP was found to be significantly higher, but bony ALP (calvarium) and circulating 1;25(OH)D were markedly decreased, in diabetic rat. The histomorphometric study showed a decreased relative osteoid volume (ROV), a decreased total osteoid volume (TOV), and an increased inert surface of the osteoid. Tetracycline (TC) labeling failed to be acquired in diabetic rat. These findings indicated that long-term insulin deficiency may be related to a lack in the maturity of the bone matrix and reduced turn-over. Transplanted rat showed a normal response to ivGTT and increased bony ALP. Histologically, ROV and TOV increased together, with acquired TC double labeling lines. These results indicated that diabetic osteopenia can be reversed by pancreatic transplantation.

Photodynamic therapy using a diode laser with mono-L-aspartyl chlorin e6 for implanted fibrosarcoma in mice

We have developed a new high-power red (664 nm) laser diode system for photodynamic therapy (PDT) with mono-L-aspartyl chlorin e6 (NPe6). Meth-A fibrosarcoma cells (1 x 10(6)) were implanted subcutaneously in the right hind leg of 4-week-old BALB/c female mice. One week later, diode laser irradiation was applied 5 h after the intravenous administration of NPe6 to each tumor-bearing mouse. In the first study, the time course of intratumor temperature increase during PDT was measured by using a 23-guage thermocouple hypodermic needle at a depth of 2 mm from the tumor surface. In the second study, 6 groups of 10 to 17 tumor-bearing mice were treated with the diode laser 5 h after intravenous administration of NPe6 at the dose of 1.25, 2.5, 5.0 or 7.5 mg/kg i.v. per mouse. Total photoirradiation ranged from 0 to 150 J/cm2 and the dose rate was adjusted to 100 mW/cm2. Percentages of cures were determined from numbers of mice apparently disease-free 50 days after treatment. The results showed that this diode laser is effective in PDT of implanted fibrosarcoma after NPe6 administration. It also confirmed that the therapeutic effects of PDT were not due to hyperthermia. Moreover, the diode laser beam was demonstrated by CCD technology to be uniform in intensity throughout the photoirradiated field.

Amphoteric drugs. I. Synthesis and antiallergic activity of [4-(diphenylmethoxy)piperidino]-, [4-(diphenylmethyl)piperazinyl]- and [4-(diphenylmethylene)piperidino]alkanoic acid derivatives

A simple method of transforming classical antihistaminics into nonsedative antiallergic agents with strong effects in rat models is described. Various [4-(diphenylmethoxy)piperidino]- (series A), [4-(diphenylmethyl)piperazinyl]-(series B) and [4-(diphenylmethylene)piperidino]alkanoic acid derivatives (series C) were synthesized and examined for antiallergic activities and effects on the central nervous system (CNS), in comparison with the corresponding N-methyl derivatives (1a--c). N-Alkylcarboxylic acids (5a--c) showed stronger inhibitory effects on compound 48/80-induced lethality in rats than the corresponding N-methyl derivatives (1a--c). In particular, N-alkylcarboxylic acids (5a) in series A exhibited approximately 100-fold stronger inhibitory effects than 1a, and were the least effective in prolonging the sleeping time on hexobarbital-induced anesthesia in mice in all series. As a result of chemical modification in series A, it was found that introduction of a methyl group at the para-position on one benzene ring in the (diphenylmethoxy)piperidine system effectively reduced CNS side-effects without reducing antiallergic activity. (+)-3-[4-[(4-Methylphenyl)phenylmethoxy]piperidino]propionic acid ((+)-5l), an optically active isomer of 5l, exhibited a stronger antiallergic effect (ED50 = 0.17 mg/kg, p.o.) than ketotifen and terfenadine in the 48 h homologous passive cutaneous anaphylaxis (PCA) test, and moreover exhibited no CNS side-effects, such as prolongation of the sleeping time on hexobarbital-induced anesthesia, at an oral dose of 30 mg/kg. Compound (+)-5l was thus proved to be a promising candidate as a nonsedative antiallergic agent.

Molecular cloning and characterization of a cDNA for bovine phospholipase C-alpha: proposal of redesignation of phospholipase C-alpha

We have isolated bovine phospholipase C (PLC)-alpha cDNA from bovine thymus. Sequence analysis showed that PLC-alpha is highly conserved among rat, mouse, and calf and that it has two Trp-Cys-Gly-His-Cys-Lys motifs completely conserved in the mammals. Southern blot analysis revealed that bovine PLC-alpha is derived from a single gene. When PLC-alpha cDNA was stably transfected in NIH3T3 cells, there was no increase in PLC activity. PLC-alpha is supposed to be a member not of PLC superfamily but of Trp-Cys-Gly-His-Cys-Lys motif-containing proteins consisting of protein disulfide isomerase, P5, ERp72, and thioredoxin. PLC-alpha should be redesignated ERp57 (ER-resided p57).

Immunohistochemical localization of estrogen receptors in the submandibular gland tumors of female rats

The localization of estrogen receptors (EsR) in the tumor tissues of submandibular glands was examined in female rats, using the indirect immunoperoxidase method in combination with the in situ hybridization technique. Tumors were experimentally produced by 9,10-dimethyl-1,2-benzanthracene (DMBA), and the tumor tissues were fixed with formalin or paraformaldehyde and then embedded in paraffin. In the DMBA-induced submandibular gland tumors, immunoreactivity to EsR-peroxidase conjugate was found in nuclei of the tumor cells which occupied the peripheral rim of the tumor cell nests. In contrast, the reactivity in the normal submandibular glands without tumor was mostly confined to nuclei of the duct cells. When EsR mRNA expression was analyzed in the tumor tissue by in situ hybridization with a cDNA probe, its distribution was identical with that of immunoreactivity to EsR. These data suggest that the ductal cells of the submandibular gland are responsive to ovarial steroids, and that estrogens may play an important role in the maintenance of growth of the submandibular gland tumors.

Alagille syndrome with a spontaneous appearance of the interlobular bile ducts

We report a rare case of a 10 year old girl diagnosed as having Alagille syndrome on the basis of a characteristic face, posterior embryotoxon, cholestasis, peripheral pulmonary artery stenosis and the absence of interlobular bile ducts in a liver biopsy at 1.5 years of age. Since 1.5 years old, she had been in good health without medication and the serum biochemical liver function tests indicated no progression of cholestasis. A second liver biopsy at 9.5 years of age showed normal interlobular bile ducts confirmed by anti-keratin staining at each of the five examined portal areas. Alagille syndrome is usually associated with the progressive disappearance of interlobular bile ducts. The findings of interlobular bile ducts in the second liver biopsy were therefore rare and unique to this case.

Fetal bile acid metabolism during infancy: analysis of 1 beta-hydroxylated bile acids in urine, meconium and feces

Fetal bile acids (1 beta-hydroxylated, 6 alpha-hydroxylated and unsaturated bile acids), especially 1 beta, 3 alpha,7 alpha, 12 alpha-tetrahydroxy-5 beta-cholan-24-oic acid (CA-1 beta-ol), have been detected in urine and feces early in life. To investigate whether a fetal pathway of bile acid synthesis exists in infancy, we measured the concentrations of bile acids in the urine, meconium and feces from normal newborns and infants by means of gas chromatography-mass spectrometry. The mean ratio of total bile acids to creatinine in urine increased between birth and 7 days and then gradually decreased; however, the concentration of total bile acids in urine remained significantly higher than that in adult urine until 3 mo of age. The main urinary bile acid was CA-1 beta-ol, and substantial amounts of fetal bile acids were detected in urine until 3 mo of age. The ratio of cholic acid to chenodeoxycholic acid was abnormally low in meconium (mean, 0.44; range, 0.19 to 0.74), and hyocholic acid constituted 19.3% of total bile acids. The mean total bile acid content of feces decreased between birth and 7 days of age and thereafter increased. The mean percentage of fetal bile acids in feces decreased after birth, but substantial amounts were present in feces until 1 mo of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence rate of recurrent Kawasaki disease in Japan

To calculate the incidence of recurrent Kawasaki disease and to discuss some potential risk factors for its recurrence, we observed a cohort consisting of those followed-up since the first episode of the disease. A total of 4560 persons, with 16,500.4 person-years were observed from the second month after the first episode of the disease to the end of 1989. The mean observation period was 3.62 years. The overall incidence rate was 5.21 per 1000 person-years, with a higher incidence within the 2 years from the first episode; although not statistically significant, the incidence was higher among males and those who experienced the first episode at < or = 2 years of age. The possibility of i.v. gamma globulin therapy being one of the risk factors was negated by a stratified analysis to control confounding factors but supported by univariate analysis.

Six missense mutations associated with type I and type II protein C deficiency and implications obtained from molecular modelling

The molecular basis of protein C deficiency was studied in three type I and three type II heterozygotes. Three probands showed thrombotic complications. All the exons and intron/exon junctions of the protein C gene were studied using a strategy combining by the polymerase chain reaction (PCR) amplification, single-strand conformational polymorphism (SSCP) analysis, and DNA sequencing of the PCR-amplified fragments. Six missense mutations were identified, including three novel ones. One was located in exon II, in which the initiating translation codon (ATG) encoding for Met at position -42 was replaced by ACG encoding for Thr. The other five were located in exon IX, and included TAC(Tyr399)-->CAC(His), CCG(Pro327)-->CTG(Leu), GAC(Asp359)-->AAC(Asn) in two cases, and GGG(Gly350)-->AGG(Arg). Four of the six missense mutations occurred in CG dinucleotide. Sequence analysis of the other exons excluded additional mutations. By restriction enzyme analysis, co-segregation of the mutation with protein C deficiency was observed in four families. The other two mutations at amino acid positions -42 and 350 were also considered to be associated with protein C deficiency due to the absence of these mutations in 50 normal individuals. A structural model of the protease domain of mutant activated protein C was constructed by the chimeric modelling method, and the resultant model suggested conformational changes due to each missense mutation identified in protein C deficiency. The present data also provide some evidence regarding the genetic heterogeneity of protein C deficiency.