Thyroid diseases among atomic bomb survivors in Nagasaki

OBJECTIVE

To elucidate the current thyroid disease status for the Nagasaki Adult Health Study cohort of the Radiation Effects Research Foundation.

DESIGN

Survey study.

SETTING

Nagasaki, Japan.

PARTICIPANTS

Cohort members of the Nagasaki Adult Health Study who received biennial health examinations from October 1984 to April 1987 (n = 2856). A total of 2587 subjects remained after exclusion of persons exposed in Hiroshima or in utero and those who were not in Nagasaki at the time of the bombing. Thyroid radiation dose by the dosimetry system established in 1986 was available for 1978 of the 2587 subjects.

MAIN OUTCOME MEASURES

Thyroid diseases were diagnosed using uniform procedures including ultrasonic scanning. The relationship of the prevalence of each thyroid disease with thyroid radiation dose, sex, and age was analyzed using logistic models.

RESULTS

A significant dose-response relationship was observed for solid nodules, which include cancer, adenoma, adenomatous goiter, and nodules without histological diagnosis, and for antibody-positive spontaneous hypothyroidism (autoimmune hypothyroidism) but not for other diseases. The prevalence of solid nodules showed a monotonic dose-response relationship, yet that of autoimmune hypothyroidism displayed a concave dose-response relationship reaching a maximum (+/- SE) level of 0.7 +/- 0.2 Sv.

CONCLUSIONS

The present study confirmed the results of previous studies by showing a significant increase in solid nodules with dose to the thyroid and demonstrated for the first time a significant increase in autoimmune disease among atomic bomb survivors. A concave dose-response relationship indicates the necessity for further studies on the effects of relatively low doses of radiation on thyroid disease.

Cell cycle-dependent expression of estrogen receptor and effect of estrogen on proliferation of synchronized human osteoblast-like osteosarcoma cells

Dual fluoroimmunohistochemical staining of estrogen receptor (ER) and bromodeoxyuridine was performed in a human osteoblastic osteosarcoma cell line, HOS TE85 cells. ER immunoreactivity was observed preferentially in the nuclei of the cells that were bromodeoxyuridine positive. ER expression at various phases of the cell cycle was investigated in HOS TE85 cells, which were synchronized at the G1/S phase boundary by intermittent exposure to thymidine and hydroxyurea. ER immunoreactivity became detectable in the S phase, decreased in the G2/M and G1 phases, and then reappeared in the S phase of the next cell cycle. Western blot analysis also showed that ER protein exists in these cells and increases in the S phase. Moreover, Northern blot analysis demonstrated that the expression of ER messenger RNA increases in the early S phase, gradually decreases during the progress of the cell cycle, and increases again in the S phase of the subsequent cell cycle. Interestingly, 17 beta-estradiol (10(-8) M) increased cell number and [3H]thymidine incorporation into DNA in the synchronized HOS TE85 cells, whereas this effect was not observed in the nonsynchronized HOS TE85 cells. The present studies suggest that the cell cycle-dependent regulation may contribute to the heterogeneity of ER expression in osteoblastic cells.

Potentiated maturation with a high proliferating activity of acute promyelocytic leukemia induced in vitro by granulocyte or granulocyte/macrophage colony-stimulating factors in combination with all-trans retinoic acid

All-trans retinoic acid (ATRA) induces differentiation of acute promyelocytic leukemia (APL), but the effect of cytokines regulating myeloid differentiation on ATRA-induced APL cells is poorly understood. In this study, maturation and proliferation of fresh APL cells were examined when induced in vitro by granulocyte or granulocyte/macrophage colony-stimulating factors (G-CSF or GM-CSF) in combination with ATRA. APL cells showed a low proliferating activity when induced by ATRA alone. In contrast, cells induced by G-CSF or GM-CSF alone showed increased DNA syntheses, the levels of which were not significantly affected by the combination of ATRA with CSFs. Interestingly, G-CSF or GM-CSF potentiated the capability of ATRA-induced cells to reduce nitroblue tetrazolium (NBT), while G-CSF or GM-CSF alone induced no NBT reduction. Furthermore, in several patients examined, APL cells induced by ATRA with G-CSF showed an increased activity of chemotaxis and CD11a expression. These findings suggest that G-CSF or GM-CSF can potentiate differentiation of ATRA-induced APL cells while stimulating their proliferating activity as well, and that G-CSF, rather than GM-CSF, may be a useful adjunct to promote ATRA-induced differentiation of APL.

Identification, developmental expression and tissue distribution of deaminoneuraminate hydrolase (KDNase) activity in rainbow trout

A deaminoneuraminosyl-glycohydrolase (KDNase), which catalyses the hydrolysis of alpha-ketosidic 2-keto-3-deoxy-D-glycero-D-galacto- nononic acid (or naturally occurring deaminated neuraminic acid; KDN) linkages in KDN-glycoconjugates, is required for their structural and functional studies since KDN residues are usually resistant to the action of known sialidases. A search for KDNase was initiated by examining various cells and tissues of rainbow trout because KDN-glycoconjugates were first found in this animal species. Tissue localization studies of KDNase activity showed it to be present in kidney, spleen and ovary. The highest KDNase activity was found in ovarian post-ovulatory follicles obtained from female fish at the time when the reproductive organ was undergoing natural effacement. Little if any activity was found in brain, heart, liver, muscle, mature eggs and testis. Developmentally, higher levels of KDNase were usually expressed 3-4 months before ovulation or spermiation. An exception to this was in the ovary (or ovarian follicles) where the most striking increase in KDNase occurred 1-2 months after the maturation of gamete cells. Enzyme extracts containing KDNase activity also contained sialidase activity. From the data based on a kinetic study using mixed substrates, both KDNase and sialidase activities were indicated to reside on a single enzyme protein. The KDN-sialidase displayed broad specificity, which could possibly limit its usefulness as a probe for KDN-glycoconjugates. Nevertheless, unlike sialidases, KDNase can selectively remove KDN residues, thus making it an important new reagent to identify KDN-glycoconjugates in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)

Facilitation of liver regeneration after partial hepatectomy by ventromedial hypothalamic lesions in rats

Whether or not the hypothalamus is involved in initiating hepatic DNA synthesis after partial hepatectomy is unclear. To determine the role of the ventromedial hypothalamic nuclei in liver regeneration after partial hepatectomy, we studied hepatic DNA synthesis during liver regeneration in rats with bilateral lesions of these nuclei. Lesions of the ventromedial hypothalamus accelerated the increase in hepatic DNA synthesis and raised the peak level of thymidine incorporation after partial hepatectomy. These effects of hypothalamic lesions were completely inhibited by hepatic vagotomy. Thus, lesions of the ventromedial hypothalamus appear to promote hepatic regeneration by increasing vagal stimulation of the liver.

Antimetastatic effects of synthetic peptides containing the core sequence of the type III connecting segment domain (IIICS) of fibronectin

The antimetastatic activities of synthetic peptides corresponding to fragments of the adhesion-related molecules, such as fibronectin and laminin, were examined. We prepared three peptides derived from the type III connecting segment domain (IIICS) of fibronectin: Glu-Ile-Leu-Asp-Val (EILDV), Glu-Ile-Leu-Asp-Val-Pro-Ser-Thr (EILDVPST), Arg-Glu-Asp-Val (REDV), and a laminin-related peptide, Tyr-Ile-Gly-Ser-Arg (YIGSR). Each peptide inhibited the experimental tumor metastasis of B16-BL6 melanoma, while EILDV had the strongest effect. The peptides conjugated with poly(ethylene glycol) (PEG) were more effective than the unmodified peptides in molar ratio terms. A mixture composed of PEG hybrids with EILDV, REDV and YIGSR significantly inhibited tumor metastasis.

Purification and enzymatic properties of peptide:N-glycanase from C3H mouse-derived L-929 fibroblast cells. Possible widespread occurrence of post-translational remodification of proteins by N-deglycosylation

Recently, we found the occurrence of N-deglycosylating enzyme, peptide:N-glycanase (PNGase), in mammalian cells and observed that PNGase is a rather common enzyme involved in post-translational remodification of proteins (Suzuki, T., Seko, A., Kitajima, K., Inoue, Y., and Inoue, S. (1993) Biochem. Biophys. Res. Commun. 194, 1124-1130). We report here a 460-fold purification to homogeneity with 11.5% yield of PNGase from crude extract of C3H mouse-derived L-929 fibroblast cells. The purified enzyme, designated as L-929 PNGase, had the apparent molecular weight of 212,000 and was composed of two 105,000 subunits. Although this enzyme was capable of hydrolyzing structurally diverse natural glycopeptide substrates bearing high mannose, hybrid, and complex-type glycan units, the activity was completely inhibited by the presence of the fucose residue either alpha-1-->3- or alpha-1-->6-linked to the proximal GlcNAc residue. The enzyme showed maximal activity at pH near 7. This and the inability to act on glycoasparagine strongly support our view that this enzyme would not be involved in lysosomal degradation pathway. L-929 PNGase was characterized by having distinctly a low Km value, which may be of physiological significance. Possible wide occurrence of N-deglycosylation of glycoproteins was shown by a data bank survey of the protein sequences showing discrepancies between those determined directly (-D-X-(S/T)-) and those deduced from cDNA sequencing (-N-X-(S/T)-). We propose here that PNGase-catalyzed N-deglycosylation is a functionally important universal feature in living cells.

Isolation, structural determination, and calcium-binding properties of the major glycoprotein present in Bufo japonicus japonicus egg jelly

Although the previous studies showed that the jelly coat is essential in anuran fertilization under natural conditions, identification and structural studies of the macromolecules that play functional roles have remained to be elucidated. In the present study we isolated acidic glycoproteins (JGP) from the solubilized egg jelly of Bufo japonicus japonicus, and showed that they were the major non-dialyzable macromolecular components of the jelly coat. JGP was a typical mucin-type glycoprotein, and it showed high degree of polydispersity in molecular masses ranging over 100-4000 kDa, but both amino acid and carbohydrate compositions were practically identical among fractions, suggesting that JGP was composed of a repeating glycoprotein unit. Four types of short O-glycan chains were isolated from JGP by reductive beta-elimination and their structures were determined as: Gal beta 1-->3[NeuAc alpha 2-->6]GalNAcol (= N-acetylgalactosaminitol), Fuc alpha 1-->2Gal beta 1-->3 [NeuAc alpha 2-->6]GalNAcol, Fuc alpha 1-->2Gal beta 1-->3[GlcNAc beta 1-->6]GalNAcol, and Fuc alpha 1-->2Gal beta 1-->3-GalNAcol. These carbohydrate units (about 80% of the mass of JGP) were linked to nearly all the serine and threonine residues which accounted for 55% of total amino acid residues. The Ca(2+)-binding property of JGP was studied by equilibrium dialysis. The high Ca(2+)-binding capacity of JGP was abolished by its desialylation of JGP and was highly dependent on the JGP concentration. When the low JGP concentrations as in the hydrated Bufo jelly were used, a 50% increment of both n (the number of binding sites) and Kd (the dissociation constant of JGP-Ca2+) values was observed. This property of JGP is suited to retaining Ca2+ and keeping its concentration at that just necessary for fertilizing sperm.

[Continuous epidural buprenorphine for postoperative pain relief in upper abdominal surgery]

To evaluate postoperative analgesia and side effects of epidural buprenorphine, 100 patients who underwent upper abdominal surgery were divided into 5 groups. All patients were given initially 0.1 mg of buprenorphine in 8 ml of 0.25% bupivacaine in bolus. Following an epidural bolus, 20 patients in each group were given 0.25% bupivacaine alone (group A), 5 micrograms buprenorphine in 1 ml of 0.25% bupivacaine (group B), 8 micrograms buprenorphine in 1 ml of 0.25% bupivacaine (group C), 12 micrograms buprenorphine in 1 ml of 0.25% bupivacaine (group D), or 15 micrograms buprenorphine in 1 ml of 0.25% bupivacaine (group E) with a portable disposable device at a rate of 1 ml.h-1 for 48 h. The analgesic efficacy in group E was superior to that in groups A, B, C and D. No significant difference was found in the incidence of side-effect among 5 groups. Therefore, epidural buprenorphine 15 micrograms in 1 ml of 0.25% bupivacaine given to patients at a rate of 1 ml.h-1 was thought to be optimal for postoperative pain relief in upper abdominal surgery in terms of its efficacy and side effects. However, 35% of these patients required supplementary systemic analgesics in the early postoperative period.

Effects of intraventricular administration of neuropeptide Y on feeding behavior in fasted female rats with ventromedial hypothalamic lesions

The role of ventromedial hypothalamic nucleus (VMN) in feeding behavior induced by central administration of porcine neuropeptide Y (NPY) in fasted female rats was investigated focusing on the effect of the intracerebroventricular (i.c.v.) injection of NPY on food intake in rats with VMN lesions after 24 h of food deprivation. Cumulative food intake was measured 1, 3 and 6 h after injection. In Exp. 1, the i.c.v. injection of NPY into intact rats stimulated food intake compared with the injection of saline 1 and 3 h after the injections in a dose dependent manner (1 h; NPY 1 microgram, 3.29 +/- 0.43, 2 micrograms, 4.64 +/- 0.88, 5 micrograms, 5.15 +/- 0.61 vs. saline 2.48 +/- 0.42 g, P < 0.05 in 2 and 5 micrograms). 5 micrograms of NPY significantly stimulated food intake 6 h later. In Exp. 2, i.c.v. injection of NPY (2 micrograms) in VMN-lesioned rats showed no significant effect on food intake compared with the injection of saline 3 weeks after VMN lesioning (1 h; NPY 2 micrograms, 2.46 +/- 0.58 vs. saline 2.39 +/- 0.12 g). These results suggest that central administration of NPY enhances food intake in fasted female rats and that the VMN is one of the crucial sites of NPY induced feeding.

Cardiac sympathetic innervation in patients with dilated cardiomyopathy--immunohistochemical study using anti-tyrosine hydroxylase antibody

Depletion of norepinephrine in the left ventricular myocardium in cases of dilated cardiomyopathy (DCM) has been suggested. However, there have been few histological studies of the sympathetic nerves, in which myocardial norepinephrine is believed to exist. We performed an immunohistological study of the density of tyrosine hydroxylase (TH, a marker of sympathetic nerves)-positive nerve fiber in endomyocardial biopsy specimens in cases of DCM using antibody against TH. TH-positive nerves were stained brown along with the myocardium, and they were more dense in the right ventricle than in the left ventricle in both the DCM and control groups. The density of TH-positive nerves in cases of DCM was significantly less than that in the control group in the subendocardial myocardium of the right and left ventricles, but especially in the left ventricle. A correlation was observed in the DCM group between the density of TH-positive nerves and the ejection fraction in the right ventricle, but not in the left ventricle. In the failing human heart, a decrease in subendocardial sympathetic nerve density may be one of the causes of myocardial norepinephrine depletion.

[Surgical treatment and long-term results of congenital heart disease in adults: early and late follow-up studies in 231 cases]

In a past one decade from January 1981 to August 1991, 231 patients over 18 years old with congenital heart disease (CHD) including 65 patients with cyanotic (C) and 166 with acyanotic (AC) diseases, were surgically treated. There were one operative death (0.6 percent mortality) and three late deaths (1.9%) in 166 patients with AC diseases, whereas there were four operative (6.1%), and four late deaths (6.1%) in 65 patients with C. These patients were followed for 3 to 124 months (the mean of 46.4 +/- 11.9) after the operation. Compared with group AC, group C showed a high rate of early postoperative deaths or late deaths. Group AC comprised patients in their forties (95 patients with ASD and 15 with PDA) and those in their thirties (26 with VSD and 13 with ECD) at the operation. On the contrary, except 5 patients with Ebstein disease, a mean age of patients of group C at the operation lay in their twenties. Surgical outcomes for adult patients of group C still pose much problems compared with AC group in terms of decreased heart function, development of collateral circulatory pathway, and impaired hepatic and renal functions by long lasting hypoxemia. In group C decreased heart function or association of abscess of the brain might be the main cause of postoperative LOS. These findings indicate that early diagnosis, recent advanced operative procedure and appropriate postoperative care can provide symptomatic remission for even adult patients with severe CHD with a low mortality.

Monoclonal antibody specific for alpha 2-->8-linked oligo deaminated neuraminic acid (KDN) sequences in glycoproteins. Preparation and characterization of a monoclonal antibody and its application in immunohistochemistry

Two particular types of sialoglycoproteins have been detected in fish: polysialoglycoproteins containing alpha 2-->8-linked polysialic acid (-->8Neu5Gc alpha 2-->)n present in unfertilized Salmonidae fish eggs, and glycoproteins bearing oligo/polymers of deaminated neuraminic acids (KDN) found in the vitelline envelope of the eggs and ovarian fluid. We report the preparation and characterization of a monoclonal antibody specifically recognizing oligo/polymers of KDN sequences in glycoproteins and its application in immunohistochemistry. Fusion of spleen cells from a BALB/c mouse immunized with a KDN-rich glycoprotein (KDN-gp) containing (-->8KDN alpha 2-->)n-->6(KDN alpha 2-->3Gal beta 1-->3G alpha lNA-c alpha 1-->3) GalNAc alpha 1-->residues, with mouse myeloma cells yielded a hybrid cell line producing a monoclonal antibody that bound to KDN-gp, but not to KDN-gp depleted of KDN residues. The specificity of the monoclonal antibody, designated mAb.kdn8kdn, was determined by an enzyme-linked immunosorbent assay using KDN-gp samples that varied in KDN content. These antigens were prepared by the selective removal of KDN residues from the native KDN-gp. The mAb.kdn8kdn reacted most strongly with the intact KDN-gp and less strongly with KDN-gp samples containing decreased numbers of KDN residues.(ABSTRACT TRUNCATED AT 250 WORDS)

Different transmissibility of 2 isolates of Seoul virus from the same wild brown rat (Rattus norvegicus)

Two Seoul virus strains were isolated from the same wild brown rat (Rattus norvegicus) by 2 different procedures. While one isolate (TR-352) by means of a cell culture system had no horizontal transmissibility in 3-week-old rats, another isolate (TR-352R) by means of inoculation to newborn rats had transmissibility in rats.

Effect of crystallization on fracture strength of castable glass-ceramics containing two crystals

The relationship between fracture strength and crystallization in castable glass-ceramics was studied using castable glass-ceramics which contained crystalline apatite and magnesium titanate. Bending strength was increased with increases in crystal phases; 90, 124, 122 and 162 MPa were recorded for as-cast specimens and specimens cerammed at temperatures of 905 degrees, 925 degrees and 945 degrees C, respectively. The results of bending tests suggest that the crystallization of magnesium titanate is more effective than that of apatite in increasing the strength of glass-ceramics. Fracture toughness in specimens reheated at 905 degrees C was doubled compared with as-cast specimens. The apatite particles precipitated during ceramming treatment were thought to be an important factor in increasing both the fracture toughness and crack pinning effect.

Identification and structural determination of the KDN-containing N-linked glycan chains consisting of bi- and triantennary complex-type units of KDN-glycoprotein previously isolated from rainbow trout vitelline envelopes

KDN-gp, which is the unique glycoprotein of the rainbow trout egg envelope, was shown to have a small amount of N-linked oligosaccharide units in addition to a large number of O-linked glycan units. Structural analysis based on chemical analysis in combination with 400 MHz 1H NMR spectroscopy revealed the presence of fully KDNosylated bi- and triantennary complex-type oligosaccharide chains, mostly fucosylated at the innermost GlcNAc residue and bisected by the GlcNAc residue linked beta 1-->4 to the beta-Man residue. The structures thus determined represent the first demonstration of N-linked glycan unit containing the KDN residues in the KDN-containing glycoproteins (see Chart 1). The KDN-gp of the rainbow trout egg envelope is a molecule that is present in the second layer of the vitelline envelope but is exposed to the outer surface around the micropyle through which sperm can get in at fertilization. Like human hematopoietic cell surface glycoproteins such as glycophorin A and leukosialin, KDN-gp, which is now characterized to contain N-linked complex-type glycan chains as minor components, is heavily O-glycosylated with alpha 2-->8-linked oligo/polyKDN-containing glycan units attached O-glycosidically to Ser/Thr residues. Although little is known about the functional roles of these glycan chains, KDN-gp appears to form a model for further study on the function of cell surface receptor for sperm in fertilization.

Novel rapid- and short-acting hypoglycemic agent, a calcium(2s)-2-benzyl-3-(cis-hexahydro-2-isoindolinylcarbonyl) propionate (KAD-1229) that acts on the sulfonylurea receptor: comparison of effects between KAD-1229 and gliclazide

Calcium(2s)-2-benzyl-3-(cis-hexahydro-2-isoindolinylcarbonyl) propionate dihydrate (KAD-1229) was found to have potent hypoglycemic effects. This study was designed to elucidate its mechanisms by comparing its action with those of the antidiabetic hypoglycemic agents known as sulfonylureas in vivo and in vitro. In fasted beagles, oral administration of 0.1 to 3.0 mg/kg of KAD-1229 induced dose-dependent and significant reductions of plasma glucose levels with 43.4% maximum reduction at 1 hr, and the significant hypoglycemic effects largely disappeared within 2 hr after oral administration; 1.0 to 10 mg/kg of gliclazide also induced dose-dependent and significant reductions of plasma glucose with 44.2% maximum reduction at 3 hr, and the hypoglycemic effects continued for over 7 hr. One and 3.0 mg/kg of KAD-1229 increased plasma insulin levels, with the peak levels at 30 min, whereas 3.0 and 10 mg/kg of gliclazide increased it with the peak levels at 1 to 2 hr after dosing. Similar rapid and short-acting hypoglycemic effects of KAD-1229 were observed in rats. This compound stimulated insulin release from isolated mouse islets at a concentration from 3 x 10(-7) M to 10(-5) M. KAD-1229 stimulated insulin release from hamster's insulin-oma cell line, HIT T15 cells, at a concentration from 10(-8) M to 10(-5) M and inhibited 86Rb+ efflux from these cells with IC50 of 8.4 x 10(-9) M. It also inhibited [3H]glibenclamide binding to microsomes from HIT T15 cells (Ki = 1.3 x 10(-8) M).(ABSTRACT TRUNCATED AT 250 WORDS)

Lamina lucida of basement membrane: an artefact

In tissues prepared with chemical fixation followed by conventional dehydration, basement membranes have been observed to be laminated structures composed of a lamina lucida and lamina densa as well as a poorly limited transitional zone referred to as the pars fibroreticularis. Scattered attempts in the application of new techniques of tissue preparation such as cryofixation or freeze substitution for the study of the basement membrane structure have been made in recent years. From these studies, the possibility has arisen in which basement membranes are composed of only the lamina densa without a lamina lucida. In recent studies in this laboratory, the attempt was made to determine whether or not this lamina lucida is an artefact, and if so, which step in the conventional method of tissue preparation is responsible for its formation. Basement membranes from diverse sources in the mouse and rat including the testis, ductus epididymis, eye, thyroid, kidney, and skin, were observed after either cryofixation by slam freezing followed by freeze substitution, or aldehyde fixation followed by freeze substitution. The basement membranes after preservation with either of these two methods were composed of only the lamina densa with no lamina lucida. It indicates that an artefactual formation of the lamina lucida occurs during dehydration in conventional tissue preparation rather than during chemical fixation. In view of the well known superiority of freeze substitution over conventional dehydration, the lamina lucida of the basement membrane is likely to be an artefact. Therefore, it is concluded that the lamina lucida is an artefact formed during conventional tissue preparation, and in its original condition in the living state, the basement membrane is composed of a single layer made up of lamina densa material.

Basic structure of basement membranes is a fine network of "cords," irregular anastomosing strands

A three-dimensional network of irregular anastomosing strands, referred to as "cords," was found to be the main component of the lamina densa of a) common, "thin" basement membranes in tissues from diverse origins including foot pad epidermis, trachea, jejunum, seminiferous tubule and vas deferens of the rat, monkey seminiferous tubule, and mouse ciliary process, b) a "double" basement membrane, the rat glomerular basement membrane, and c) "thick" basement membranes including rat Reichert's membrane, mouse lens capsule and the Engelbreth-Holm-Swarm (EHS) tumor matrix. The average thickness of the cords was 3.2-4.8 nm, 4 nm, and 4.7-5 nm, respectively, in these three types of basement membranes. The mean diameter of the intercordal spaces, or openings of the network, averaged 14 nm with a range from 8 nm in the glomerular basement membrane to 21.9 nm in the lens capsule. After cryofixation followed by freeze substitution or freeze drying, similar cord networks were observed in all basement membranes examined which included two thin basement membranes, that of the rat epididymis and seminiferous tubules, and three thick basement membranes, that is, the lens capsule and the EHS tumor matrix of the mouse, and rat Reichert's membrane. In addition, following the co-incubation of laminin, type IV collagen and heparan sulfate proteoglycan at 35 degrees C, a precipitate was formed which was found to contain lamina densa-like sheets and large semisolid masses. Both types of structures were found to be made up of a network of 3 nm wide cords, which resembled that of natural basement membranes. With the immunoperoxidase technique, these cords were stained for major basement membrane components including laminin, type IV collagen, heparan sulfate proteoglycan, entactin, and fibronectin. Ribbon-like "double tracks" 4.5 nm in width and being distributed along cords have been identified as the form taken by heparan sulfate proteoglycan in basement membranes. Following mild plasmin treatment, most of the cord components were digested away leaving behind a network of fine filaments found to contain type IV collagen. Each cord, therefore, is organized by a type IV collagen core filament which is surrounded by a plasmin-sensitive sheath containing other basement membrane components. Two types of minor structural components, that is, 7-10 nm wide straight "basotubules" and 3.5 nm wide particulate structures referred to as "pentosomes" were associated with cord network in some basement membranes.(ABSTRACT TRUNCATED AT 400 WORDS)

Isolation and characterization of a phospholipase A2 inhibitor from the blood plasma of the Thailand cobra Naja naja kaouthia

A phospholipase A2 (PLA2) inhibitory protein was purified from the blood plasma of the Thailand cobra Naja naja kaouthia by sequential chromatography on Sephadex G-200, DEAE Affi-Gel Blue, and Protein-Pak G-Butyl columns. The purified inhibitor was a glycoprotein with an apparent molecular mass of about 90 kDa and contained 25- and 31-kDa subunits with a molar ratio of 1:2. The 31-kDa subunit contained a glycosidic chain and the molecular mass was reduced to 28 kDa by N-glycosidase F treatment. The amino acid compositions of the two subunits were characterized by their high content of cysteine residues. The inhibitor inhibited group II as well as group I PLA2's. Since the fundamental properties were different from those of the two Crotalidae inhibitors already reported, the cobra inhibitor might be a new type of PLA2 inhibitor.