Murine Ia-associated invariant chain's processing to complex oligosaccharide forms and its dissociation from the I-Ak complex

The processing of murine invariant chain (Ii) to a cell surface form bearing complex N-linked oligosaccharides has been demonstrated in the B cell lymphoma, AKTB-1b. In addition, the rate of processing of pulse-labeled Ii has been determined relative to its rate of dissociation from the alpha/beta complex of I-Ak. Ii, alpha-, and beta-chains were immunoprecipitated with anti-I-Ak or anti-Ii monoclonal antibodies. The heretofore uncharacterized complex oligosaccharide form of Ii (Ii-c) was identified in gel-purified immunoprecipitates by peptide mapping with reverse-phase HPLC. Ii-c is resistant to deglycosylation by Endo H, which is specific for high-mannose N-linkages, but can be digested with Endo F, a glycosidase capable of cleaving both complex and high-mannose N-linked oligosaccharides. Immunoprecipitation of surface iodinated cells indicates that Ii-c is expressed on the plasma membrane. Pulse-chase metabolic labeling data show that the processing of Ii to Ii-c occurs with a t1/2 of about 120 min. In contrast, the processing of both alpha- and beta-chains of I-Ak to complex forms occurs with a t1/2 of 15 to 20 min. Our data show that Ii-hm begins to dissociate rapidly from the I-Ak complex after 100 to 120 min of chase. Only a small amount (less than 5% on a per mole basis) of Ii-c was found associated with the I-Ak complexes after 300 min of continuous metabolic labeling. These results are consistent with Ii serving as a carrier for Ia antigens as they are transported to the cell surface. In addition, they suggest that the processing of Ii to Ii-c, or a late processing event of the alpha- and beta-chains, such as their sialylation, may be a possible mechanism for inducing the dissociation of Ii from the I-Ak complex.     

Changes in the Activity of the Maturation-Promoting Factor Are Correlated with Those of a Major Cyclic AMP and Calcium-Independent Protein Kinase During the First Mitotic Cell Cycles in the Early Starfish Embryo

Many studies suggest that MPF activation depends on protein phosphorylation or that MPF is itself a protein kinase. In the present report, cyclic variations of MPF activity have been correlated in vivo with changes in the extent of protein phosphorylation or in vitro with changes of a major protein kinase during the first cell cycles of fertilized starfish eggs. This cycling protein kinase neither requires cAMP nor Ca²⁺. Neither colchicine nor aphidicoline, which inhibits cleavage and chromosome replication respectively, was found to suppress the synchronous and cyclic variations of both MPF and protein kinase activities. Protein synthesis was found to be required for both MPF and protein kinase activities to reappear after their simultaneous drop at the time of mitotic or meiotic cleavages. Production of either MPF or protein kinase activities is not the immediate result of protein synthesis since there is a delay at each cell cycle between the time when protein synthesis is required and the time when both MPF and protein kinase activities are produced. This suggests that both MPF and protein kinase activities might involve some post-translational modification of a precursor protein synthesized during the preceeding cell cycle.     

Prolonged increased responsiveness of canine peripheral airways after exposure to O3

Because it is relatively insoluble, the oxidant gas O3 may penetrate to small peripheral airways when it is inhaled. Increased responsiveness in large airways after O3 breathing has been associated with the presence of inflammatory cells. To determine whether O3 produces prolonged hyperresponsiveness of small airways associated with the presence of inflammatory cells, we exposed the peripheral lungs of anesthetized dogs to 1.0 ppm O3 for 2 h using a wedged bronchoscope technique. A contralateral sublobar segment was simultaneously exposed to air as a control. In the O3-exposed segments, collateral resistance (Rcs) was increased within 15 min and remained elevated approximately 150% throughout the 2-h exposure period. Fifteen hours later, the base-line Rcs of the O3-exposed sublobar segments was significantly elevated, and these segments demonstrated increased responsiveness to aerosolized acetylcholine (100 and 500 micrograms/ml). There were no differences in neutrophils, mononuclear cells, or mast cells (numbers or degree of mast cell degranulation) between O3 and air-exposed airways at 15 h. The small airways of the lung periphery thus are capable of remaining hyperresponsive hours after cessation of localized exposure to O3, but this does not appear to be dependent on the presence of inflammatory cells in the small airway wall.     

A 41-kilodalton protein is a potential substrate for the p210bcr-abl protein-tyrosine kinase in chronic myelogenous leukemia cells.

Chronic myelogenous leukemia (CML) is characterized by a translocation involving the c-abl protein-tyrosine kinase gene. A chimeric mRNA is formed containing sequences from a chromosome 22 gene (bcr) at its 5' end and all but the variable exon 1 of c-abl sequence. The product of this mRNA, p210bcr-abl, has constitutively high protein-tyrosine kinase activity. We examined K562 cells and other lines established from CML patients for the presence of phosphotyrosine (P-Tyr)-containing proteins which might be p210bcr-abl substrates. Two-dimensional gel separation of 32P-labeled proteins followed by phosphoamino acid analysis of 25 phosphoproteins, which comprised the major alkali-stable phosphoproteins, indicated that three related proteins of 41 kDa are the most prominent P-Tyr-containing proteins detected by this method. The 41-kDa phosphoproteins are found in two other CML lines that we examined but not in lines of similar lineage isolated from patients with distinct leukemic disease. A protein that comigrates with the major form of pp41 (pp41A) and contains P-Tyr is also found in murine fibroblasts and B-lymphoid cells transformed by Abelson murine leukemia virus, which encodes the v-abl protein, and in platelet-derived growth factor-treated fibroblasts, in which it has been described previously. We analyzed three pairs of Epstein-Barr virus-immortalized B-cell lines from individual CML patients and found that only the lines in which active p210bcr-abl was present contained detectable pp41. We also performed immunoblotting with anti-P-Tyr antibodies on the same CML cell lines and detected at least four other putative substrates of p210bcr-abl, which were undetected with use of the two-dimensional gel technique.     

中国平脉树螽属五新种记述：直翅目：螽斯科：树螽亚科

本文报道中国平脉树螽属5个新种。每个新种皆有详细的形态描述和形态特征图。所有模式标本存于北京农业大学昆虫标本室。     

Assessment of fine needle aspiration as a screening test for occult prostatic carcinoma

As part of an ongoing study of objective parameters of prognostic value in prostatic carcinoma, a routine procedure was developed to aspirate all prostates prior to surgery. These targets were different from those of other workers in the field of prostatic fine needle aspiration (FNA), who generally advocate that FNA be confined to suspicious nodules. The aspirations were performed by a large group of practicing urologists who had no special training in prostatic FNA except for guidelines provided by their peers and information available in the literature. This approach permitted an assessment of the performance of FNA as a screening test rather than as a diagnostic procedure. During the period from January 1983 to February 1987, 1,683 patients had prostatic FNAs performed (plus subsequent histologic study). The following diagnoses were rendered: "inadequate/scanty specimen" in 625 cases (37%), "negative/atypical" in 844 cases (50%) and "suspicious/positive" in 214 cases (13%). Histologic examination showed stage A1 prostatic adenocarcinoma in 18 patients. The cytologic diagnoses on these 18 patients were inadequate/scanty in 3 (17%), negative/atypical in 13 (72%) and suspicious/positive in 2 (11%). Of the 214 patients with a positive/suspicious diagnosis by FNA, the diagnosis of prostatic carcinoma was confirmed by tissue evidence in 200; the other 14 patients had either no evidence of prostatic carcinoma on surgical biopsy (needle biopsy/transurethral resection/suprapubic prostatectomy) or had no surgical biopsy. Eight of the 14 patients developed clinical evidence of carcinoma, 1 died of urinary bladder carcinoma and 1 was lost to follow-up. In the remaining four patients, there is still no evidence of prostatic carcinoma after about one-and-one-half years of follow-up. These results indicate that (1) specialized training is required in order to obtain adequate smears by prostatic FNA; (2) prostatic FNA is not a good screening technique for detecting stage A1 prostatic carcinoma; and (3) a positive diagnosis by prostatic FNA, even when not confirmed by tissue biopsy, is still an indication of disease.     

Capitalist Philanthropy and Russian Revolutionaries: The Jesup North Pacific Expedition (1897-1902)

This review of the Jesup North Pacific Expedition, still the most important expedition in American anthropology, gives an idea of the goals and hazards of fieldwork around 1900, the pitfalls of international research, the tensions between anthropologists and host populations, the careers of early anthropologists, the role of private philanthropy, and the character of anthropology at the turn of the century. Franz Boas was the Expedition's linchpin. His organization of the Expedition, the way he handled problems, and his personal concerns reveal aspects of his view of anthropology and some of his basic attitudes.