Differentiation of Langerhans Cells from Interdigitating Cells Using CD1a and S-100 Protein Antibodies

The present study shows that Langerhans cells can be differentiated from Interdigitating cells at the light microscopic level. Superficial lymph nodes and skin taken from necropsies and the lymph nodes of dermatopathic lymphadenopathy (DPL) were used for this experiment. Sections of lymph node and skin were embedded using the acetone, methyl benzoate and xylene (AMeX) method and dendritic cells were immunostained with anti S-100 protein antibody (S-100, and OKT-6 (CD1a) using the restaining method. Langerhans cells in the skin were positive for both CD1a and S-100. Dendritic cells positive for both CD1a and S-100, and dendritic cells positive for S-100, but not for CD1a were observed in superficial lymph nodes. In normal superficial lymph nodes, there were more interdigitating cells than Langerhans cells. The majority of the dendritic cells in the DPL were Langerhans cells. We conclude that the S-100 and CD1a positive cells are Langerhans cells, and the S-100 positive-CD1a negative cells are interdigitating cells.     

A new member of the protein kinase C family, nPKC theta, predominantly expressed in skeletal muscle.

A new protein kinase C (PKC)-related cDNA with unique tissue distribution has been isolated and characterized. This cDNA encodes a protein, nPKC theta, which consists of 707 amino acid residues and showed the highest sequence similarity to nPKC delta (67.0% in total). nPKC theta has a zinc-finger-like cysteine-rich sequence (C1 region) and a protein kinase domain sequence (C3 region), both of which are common in all PKC family members. However, nPKC theta lacks a putative Ca2+ binding region (C2 region) that is seen only in the conventional PKC subfamily (cPKC alpha, -beta I, -beta II, and -gamma) but not in the novel PKC subfamily (nPKC delta, -epsilon, -zeta, and -eta). Northern (RNA) blot analyses revealed that the mRNA for nPKC theta is expressed predominantly in skeletal muscle. Furthermore, nPKC theta mRNA is the most abundantly expressed PKC isoform in skeletal muscle among the nine PKC family members. nPKC theta expressed in COS1 cells serves as a phorbol ester receptor. By the use of an antipeptide antibody specific to the D2-D3 region of the nPKC theta sequence, nPKC theta was recognized as a 79-kDa protein upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis in mouse skeletal muscle extract and also in an extract from COS1 cells transfected with an nPKC theta cDNA expression plasmid. Autophosphorylation of immunoprecipitated nPKC theta was observed; it was enhanced by phosphatidylserine and 12-O-tetradecanoylphorbol-13-acetate but attenuated by the addition of Ca2+. These results clearly demonstrate that nPKC theta should be considered a member of the PKC family of proteins that play crucial roles in the signal transduction pathway.     

Significant antitumor effect of a synthetic lipid A analogue,DT-5461, on murine syngeneic tumor models

Summary The antitumor effect of a synthetic lipid A analogue, DT-5461, was investigated using syngeneic tumor models in mice. Intravenous injection of DT-5461 into mice transplanted with solid tumors of MethA fibrosarcoma, MH134 hepatoma, MM46 mammary carcinoma, Lewis lung carcinoma (3LL), and colon adenocarcinomas 26 and 38 resulted in significant reductions in the weight of all tumors except Colon 26, with marked hemorrhagic necrosis of tumor tissues. Efficacy was almost equal to that of anEscherichia coli-type synthetic lipid A (compound 506), and also to those of some chemotherapeutics including Adriamycin, mitomycin C, fluorouracil and cisplatin. Furthermore, DT-5461 was more effective than other immunotherapeutics, including picibanil (OK-432) and lentinan. However, its antitumor effects were inferior to those of Adriamycin or OK-432 against the malignant ascites caused by intraperitoneal inoculation with MethA or with MH134 cells; life span was not prolonged by either intraperitoneal or intravenous administration. In addition, although DT-5461 showed direct inhibitory effects on the in vitro growth of MethA or MH134, these were much weaker than those of Adriamycin. These findings clearly indicated that DT-5461 with systemic administration is a highly effective antitumor agent on solid tumors, and suggest that the antitumor effect of DT-5461 with potent necrotizing activity might derive from indirect mechanisms related to the activation of host immune systems and not to the weak direct cytotoxicity.     

Structural changes of alpha2- and ovomacroglobulins

The plasma α₂-macroglobulin and its egg white homologue ovomacroglobulin were purified from several different species and their structure before and after the reaction with proteinases studied by electron microscopy. The negatively stained specimens showed either a ringlike structure or a flowerlike one before the reaction with proteinses, but their structures changed into open rectangular ones after the reaction. The translational frictional ratio f/f ₀ of human α2-macroglobulin and crocodilian ovomacroglobulin given in the literature is between 1.5 and 1.6 before and after the reaction with proteinases. The value reflects asymmetry due not to a high axial ratio, but rather to an openness of the structure resulting in a partially free draining character of the molecules. The computational method developed by Bloomfield and his co-workers based on the formalism of Kirkwood is used to calculate the frictional ratio of several models constructed from small spheres. The overall shape of the models is derived from electron micrographs. Although the degree of hydration is an unknown parameter in the calculation, reasonable agreement is obtained between the experimental values of f/f ₀ and the calculated ones. Combination of electron microscopic and hydrodynamic methods would be fruitful in the structural study of giant proteins such as α₂-macroglobulin.     

Purification and characterization of ascamycin-hydrolysing aminopeptidase from Xanthomonas citri.

Intact obese rats were hyperinsulinaemic, had higher rates of whole-body fatty acid synthesis, higher activities of hepatic acetyl-CoA carboxylase and tyrosine aminotransferase and a higher hepatic glycogen concentration than intact lean animals. Adrenalectomy abolished all these factors of the obese phenotype. Treatment of adrenalectomized rats with corticosterone for 24 h increased the rate of whole-body fatty acid synthesis to the same extent in both phenotypes, but caused a larger increase in glycogen concentration, tyrosine aminotransferase activity and plasma insulin concentration in obese rats.     

Production of a protein A--lymphotoxin hybrid protein for cancer-targeted therapy.

A hybrid protein between staphylococcal protein A and human lymphotoxin, ALT, was produced in Escherichia coli by expression of a recombinant plasmid containing the respective genes. IgG-binding activity of ALT was confirmed by Western blotting analysis and by affinity purification with IgG-Sepharose column chromatography. The purified ALT had cytotoxicity on mouse L-929 cells and its specific activity was approximately 3.5-5.0 X 10(6) U mg-1. ALT was partially degraded by a protease including in the E. coli lysate or trypsin and was converted to lymphotoxin which lacks the NH2-terminal 19 residues but possesses higher cytotoxic activity than ALT.     

Effects of body and head positions on bilateral difference in tympanic temperatures

We have examined the nonparallel changes in tampanic membrane temperatures (T _ty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the T _ty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in T _ty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the T _ty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in T _ty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the T _ty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using ^99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in T _ty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation.     

Morphology and molecular phylogeny of the marine diatom genus Nagumoea (Bacillariophyceae) from Japan

The canal-bearing diatom genus Nagumoea, described based on only morphological evidence, was tentatively assigned to the order Bacillariales, although its phylogenetic position remained unclear. Because three isolates of Nagumoea (SK002, SK024 and SK053) were successfully established from Japanese coasts, we performed their morphological observations and molecular phylogenetic analyses to discuss the phylogeny and taxonomic position of this genus. Strains SK002 and SK024 were identified as Nagumoea africana, whereas SK053 conformed with Nagumoea serrata. There was high interspecific divergence between N. africana and N. serrata in the rbcL sequences (8.03–8.17%), indicating their distinctness. Furthermore, intraspecific variations were detected within N. africana (2.35%) in the rbcL, implying its cryptic diversity. The maximum likelihood and Bayesian phylogenetic trees inferred from the plastid rbcL, psbC and nuclear 18S rDNA genes recovered Nagumoea as monophyletic with strong statistical support and embedded within an unresolved, poorly supported lineage containing Achnanthes, Craspedostauros, Staurotropis and Undatella in the canal-bearing order Bacillariales (= the family Bacillariaceae). Although the constrained tree based on the monophyly of Nagumoea and the other canal-bearing clade (Surirellales and Rhopalodiales) was statistically rejected by the topology tests, the phylogenetic position of Nagumoea with other Bacillarialean members remains equivocal. The possession of two plastids positioned fore and aft, observed in the present study, and lack of keel, typical of the Bacillariales, indicate the possibility of Nagumoea being part of the ingroup of the Bacillariales or its closely related outgroup.