Antigen-induced lymphomagenesis: identification of a murine B cell lymphoma with known antigen specificity

CH12, a murine B cell lymphoma derived in B10 H-2aH-4bp/Wts mice after transfer of SRBC hyperimmunized spleen cells into an adult-thymectomized, sublethally irradiated, syngeneic recipient, is demonstrated to bear surface IgM specific for a determinant found on SRBC and ChRBC. The Ig specificity has been demonstrated by rosetting assays and complement-dependent hemolysis. The removal of CH12 surface IgM by capping with anti-mu or with anti-CH12 idiotype, but not with anti-gamma or with irrelevant anti-idiotype, eliminated the formation of rosettes between CH12 and SRBC or ChRBC. The absorption of CH12 Ig produced in vitro, with either SRBC or ChRBC but not with HRBC, removed all hemolysin activity against SRBC, demonstrating that only one CH12 product was responsible for the reactivity with both SRBC and ChRBC. CH12 has a surface phenotype of a relatively mature B cell expressing surface Ig (IgM-mu,kappa) and la antigens, but lacking Thy-1 or detectable Fc or C3 receptors. CH12 also expresses the antigen Lyt-1. Growth of CH12 in vivo or in vitro results in the generation of up to 3% direct PFC and serum hemolysin, which shows that CH12 is not irretrievably "frozen". The generation of PFC and serum hemolysin is associated with increased population density, and the rate of PFC and serum hemolysin accumulation cannot be explained by simple cell division. A continuously secreting hybridoma derived from CH12 was used to purify the CH12 IgM to facilitate studies of protein sequence and idiotype.     

Correction of lower eyelid ptosis in the anophthalmic orbit: a long-term follow-up

We describe a 10-year review of 53 patients having had correction of lower eyelid ptosis using fascia lata sling suspension by the operation first described in 1973. The overall conclusion is that this continues to be a reliable procedure with a low complication rate. Four major changes relating to operative technique that create a better result are as follows: (1) the surgical correction must begin with a prosthesis that is ideal for the socket; (2) the fascial strip is narrower at 2 mm; (3) the lateral orbital rim burr hole is placed higher; and (4) the passage of the fascial strip is facilitated by the use of Wright's needle. The optimal sequence of operative procedures in the anophthalmic orbit syndrome is (1) correction of enophthalmos and superior sulcus depression, (2) correction of lower eyelid ptosis, and (3) correction of upper eyelid ptosis.     

Influenza virus hemagglutinin expression is polarized in cells infected with recombinant SV40 viruses carrying cloned hemagglutinin DNA

Primary cell cultures of African Green monkey kidney (AGMK) contain polarized epithelial cells in which influenza virus matures predominantly at the apical surfaces above tight junctions. Influenza virus glycoproteins were found to be localized at the same membrane domain from which the virus budded. When polarized primary AGMK cells were infected with recombinant SV40 viruses containing DNA coding for either an influenza virus H1 or H2 subtype hemagglutinin (HA), the HA proteins were preferentially expressed at the apical surface in a manner identical to that observed in influenza virus-infected cells. Thus, cellular mechanisms for sorting membrane glycoproteins recognize some structural feature of the HA glycoprotein itself, and other viral proteins are not necessary for this process.     

Reversal of X-inactivation in female mouse somatic cells hybridized with murine teratocarcinoma stem cells in vitro

A series of near-diploid embryonal carcinoma-like hybrid cells were obtained from polyethylene glycol mediated cell fusion between murine embryonal carcinoma cells (PSA-6TG1 or OTF9-63) having one X chromosome and thymocytes or bone marrow cells from female mice carrying Cattanach's or Searle's translocation. Prior to fusion with EC cells the somatic cells are presumed to contain only one active X chromosome. Following hybrid formation, the chronology of X chromosome replication and the expression of X-linked gene Pgk-1 indicated that all X chromosomes contributed by both parents were active in these hybrids. Experiments were performed to rule out the possibility that the hybrids were formed by fusion of EC cells with rare somatic cells in which both X chromosomes were active. Taken together the data indicate that within four days of fusion there is reactivation of the entire inactive X chromosome.     

Pregnancy diagnosis and assessment of fetal numbers in the ewe in a commercial setting

Jugular plasma progesterone concentrations were used to accurately predict open ewes (96 +/- 3%) in early pregnancy, but they less accurately predicted subsequent lambing especially during the late breeding season and most of the seasonal anestrus. Progesterone values clearly indicated that 500 I.U. of P.M.S.G. elevated ovulation rate in synchronized ewes, but did not clearly indicate fetal numbers. During late pregnancy (88-108 days), abdominal palpation, doplar ultrasound and serum progesterone analysis were equally efficacious in predicting lambing (86 +/- 9.8%, 90 +/- 9.0% and 87 +/- 4.1%, respectively), but a high percentage of ewes lambed that were diagnosed as nonpregnant (30 +/- 15.0%, 48 +/- 17.3% and 25 +/- 8.4%, respectively). Accuracy of the serum progesterone test improved the later the test was performed, although considerable individual overlap existed. Progesterone values for ewes bearing 1, 2, or greater than 2 fetuses at 94 to 95 days of gestation differed (5.5 +/- 0.3, 8.0 +/- 0.4 and 12.4 +/- 2.1, respectively (P < 0.05), whereas at 103 to 108 days values for ewes carrying two or more fetuses did not differ.     

Blood osmolality in vitro: dependence on PCO2, lactic acid concentration, and O2 saturation

Changes of osmolality (Osm) were measured by freezing-point determination in true plasma of 10 healthy subjects. This was done after equilibration with CO2 (0.5-10.0%), after the addition of lactic acid (10 and 20 mmol/l), and after deoxygenation. The graph for the dependence of Osm on CO2 partial pressure (PCO2) in oxygenated blood resembles the classical CO2 absorption curve. The increase of Osm with PCO2 (approximately 0.2 mosmol . kg H2O-1 . Torr-1) is almost as great as the increase in dissolved CO2 plus bicarbonate (HCO-3). Addition of lactic acid shifts the curve upward by only 0.6 mosmol/mmol because of displacement of HCO-3. Deoxygenation has no significant effect at constant PCO2 despite an increase in [HCO-3]. This is probably due to the binding of 2,3-diphosphoglycerate to hemoglobin. It can be seen in the Osm-pH diagram that differences between CO2 and lactic acid titration largely disappear. For each lactic acid concentration there is a linear dependence corresponding to the linear [HCO-3]-pH relation in plasma. At constant pH, Osm increases after deoxygenation. The observed in vitro relation might explain part of the osmolality increase during physical exercise.