Histopathological observations of spontaneous regression of Rous sarcomas in Japanese quails.

Turmors induced in Japanese quails by the Schmidt-Ruppin strain of Rous sarcoma virus were examined histopathologically. The following three phases were recognized in the quails whose tumors regressed finally (regressor). Phase I was between days 4 and 7 of virus inoculation, when growth of tumor cells was seen with predominant infiltration of heterophils. Phase II, from days 10 to 14, was characterized by necrosis of tumor cells and focal accumulation of lymphoid cells which frequently formed follicle-like nodules. In phase III from days 18 to 24, tumor cells and heterophils disappeared, whereas diffuse infilitration of lymphoid cells, plasma cells and histiocytes were demonstrated. In the quails whose tumors progressed (progressor), growth of tumor cells and infiltration of heterophils at phase I seemed to follow a pattern similar to that of regressors, but subsequent infiltration and focal accumulation of lymphoid cells were rare. These morphological findings suggested an immunological reaction against tumor cells by lymphoid cells.     

Generalized and localized biased hypermutation affecting the matrix gene of a measles virus strain that causes subacute sclerosing panencephalitis.

The matrix (M) genes of Yamagata-1 strain subacute sclerosing panencephalitis virus passaged in African green monkey kidney cells and human neuroblastoma cells displayed strikingly nonrandom sequence divergence. The genes of both substrains shared a large number of uridine (U) to cytidine (C) transitions, but the latter contained numerous additional U to C changes in a localized region. Over 90% of the additional mutations were identical to the hypermutated nucleotides in the M gene found in a measles inclusion body encephalitis case. The nonrandom nature, the apparent host dependency, and the abrupt boundaries of these mutations suggest that these mutations might be caused by an extrinsic biased mutational activity rather than intrinsic polymerase errors. This mutational activity might account for the extraordinarily high C to U ratios in the non-protein-coding regions of both the M and fusion genes of wild-type measles virus.     

Gall cleaning by the aphidHormaphis betulae

Gall-cleaning behavior of the aphidHormaphis betulae is described. Honeydew is pushed out of the gall resembling toothpaste appearing out of a tube. Immatures of all instars were observed pushing out honeydew, although 88% of the laborers were 1st instar. No aphids attacked other insects placed in the gall. It is suggested that labor has evolved without accompanying defense behavior against predators in the tribe Hormaphidini.     

Characterization of antisera directed against follistatin/activin-binding protein peptides.

An attempt was made to develop immunologic probes directed against follistatin/activin-binding protein (ABP), for use in investigating the distribution of ABP in various tissues. Five oligopeptides corresponding to different regions of the predicted ABP amino acid sequence (peptides 1-12, 28-43, 123-134, 270-281 and 300-315) were synthesized chemically, and coupled to Limulus polyphemus hemolymph hemocyanin. The peptide-hemocyanin conjugates were then used to immunize rabbits, and the immunoresponses were monitored by enzyme-linked immunosorbent assay. Reactivity of the antipeptide antisera with ABP was determined by SDS-polyacrylamide gel electrophoresis and immunoblotting analysis. All of the peptides produced immune responses. The antiserum to peptide 123-134 recognized all forms of ABP, whereas the antiserum to peptide 300-315 reacted specifically and sensitively with the long forms of ABP. These two antisera exhibited only a limited cross-reaction with other proteins or none at all. Therefore, they will be useful for studying the distribution of ABP in various tissues.     

Isolation and characterization of canine distemper virus-specific RNA

Ten species of virus-specific RNA were detected in Vero cells infected with the FXNO strain of canine distemper virus (CDV). The largest RNA was the genome-sized RNA and the nine smaller species were polyadenylated RNAs. Similar results were obtained for nine other strains of CDV. The molecular weights of these ten RNAs were determined to be 4.61 X 10(6), 2.46 X 10(6), 1.52 X 10(6), 1.32 X 10(6), 1.19 X 10(6), 1.07 X 10(6), 0.77 X 10(6), 0.65 X 10(6), 0.58 X 10(6), and 0.48 X 10(6). By in vitro translation of the polyadenylated RNAs in a rabbit reticulocyte lysate system, three different proteins which probably correspond to H, NP, and M were synthesized from the fraction containing RNAs 7, 8, 9, and 10.     

Optimal conditions for blastogenic response of peripheral blood lymphocytes to T and B cell mitogens in cynomolgus monkeys

Optimal conditions for the mitogen-induced proliferation of T and B lymphocytes of cynomolgus monkeys were determined. The T cell mitogens concanavalin A and phytohemagglutinin, at concentrations of 1.25–10 μg/ml and 1.25–10 μg/ml, respectively, and the T and B cell mitogen pokeweed mitogen, at concentrations of 0.2–10 μg/ml, induced high lymphoproliferative responses, the average stimulation index (SI) being 34–93. Since suitable mitogens have not been reported for monkey B cells, we tested three types of lipopolysaccharide (LPS): two derived from Escherichia coli—one extracted with phenol and one extracted with trichloroacetic acid (TCA); and one derived from Salmonella typhimurium, extracted with phenol. All three LPS had a high mitogenic effect for monkey lymphocytes, with SI of 2.3–6.4. The highest response was observed for 25 μg/ml of Salmonella LPS, and the addition of trypsin to the culture augmented the proliferative response of low or non-responder lymphocytes. © 1994 Wiley-Liss, Inc.     

Transport of 1,5-anhydro-D-glucitol into insulinoma cells by a glucose-sensitive transport system

The uptake of 1,5-anhydro-D-glucitol (1,5-AG) occurs by passive mechanisms in cells or tissues that have passive glucose transporters. It is known that serum 1,5-AG concentrations are reduced in patients with diabetes mellitus. To elucidate the metabolism of this substance and its physiological role in pancreatic β-cells, we assayed 1,5-AG transport in the insulinoma-derived cell lines, RINr and MIN6. Both cell lines showed an insulin-insensitive, concentration-dependent uptake of 1,5-AG with a saturation time of approximately 120 min, and most of the 1,5-AG in the cytoplasm was in the free form. A biphasic saturation curve was obtained using a wide range of 1,5-AG concentrations, suggesting that accumulation was mediated by a high affinity and a low affinity transporter. The high affinity transporter had a K_m of 10.4 in RINr cells and 13.0 mM in MIN6 cells, and the low affinity transporter had a K_m of 131 in RINr cells and 211 mM in MIN6 cells. Uptake of 1,5-AG was markedly inhibited by phloretin and cytochalasin B, but was only slightly affected by phloridzin. Uptake of 1,5-AG was markedly inhibited by glucose at physiological concentrations (1.0–10 mM), as well as by galactose and mannose. The 1,5-AG concentration required to inhibit 2-deoxyglucose uptake exceeded that of glucose by >100 times, being much higher than the physiological concentrations of 1,5-AG. These results indicate that the 1,5-AG carrier system in insulinoma cells is distinct from that in either the somatic cells or renal tubular cells. These findings also suggest that a unique 1,5-AG transport system is present in pancreatic β-cells.