Assignment of the prealbumin (PALB) gene (familial amyloidotic polyneuropathy) to human chromosome region 18q11.2–q12.1

Summary The assignment of the human prealbumin (PALB) gene to chromosome region 18q11–q12.1 has been achieved using a human genomic probe in the study of human-mouse somatic cell hybrids and by in situ hybridization. Because familial amyloidotic polyneuropathy was reported previously to be due to a mutation in prealbumin, it can be inferred that the gene for this disorder also maps to 18q11.2–q12.1.     

Time-Lapse Cinemicrographic Studies of X-Irradiated HeLa S3 Cells: II. Cell Fusion

Analysis of time-lapse cinemicrographs of X-irradiated HeLa S3 cells has shown that the incidence of cell fusion was increased from 0.9% (following 1267 divisions) in control cells to an average of 22% (following 655 divisions) in cells irradiated with 500 rad doses of 220 kv X-rays. The incidence depended on the stage of the generation cycle at which the parent cells were irradiated. It was nearly constant in the first three postirradiation generations. Fusion occurred at all stages of the generation cycle, but preferentially during the first 20%. Cells undergoing fusion progressed more slowly through the generation cycle and had a higher probability of disintegrating than did irradiated cells that did not fuse. The occurrence of fusion was clonally distributed in the population. It took place only between sister (or closely related) cells. Protoplasmic bridges were often visible between sister cells prior to fusion. Giant cells arose only as a result of fusion. The incidence of multipolar divisions, though higher than in unirradiated cells, was only 5.5% in cultures irradiated with 500 rads. Fusion occurred following 85% of the multipolar divisions and was often followed by a multipolar division.     

Cholinesterase Levels in Blood Plasma and Erythrocytes from Calves,Normal Delivering Cows and Cows Suffering from Parturient Paresis

Plasma cholinesterase (pChE) levels and erythrocyte acetylcholinesterase (eAChE) levels were studied in 6 cows before, during and after parturition (Group I), their calves (Group II), 38 cows suffering from parturient paresis (Group III) and 14 newly delivered non-paretic cows (Group IV). The mean of the pChE level in Group I was 1.5 μkat/1 ± 0.20 before parturition and decreased significantly (P ≦ 0.05) to 1.2 ukat/1 ± 0.16 after parturition. The eAChE level was before parturition ≅ 140 ukat/1 and decreased to ≅ 130 μkat/1 4–5 weeks after parturition. At birth the pChE level was 12.8 ukat/1 ± 5.9 in Group II. After 4 weeks the level had decreased to 2.3 ukat/1 ±0.3. In the bull calves the pChE level started to increase when they were 6 weeks old and reached a level of 5.7 μkat/1 ± 0.6 before slaughter at 6 months of age. The heifers did not show this increase. They had a level of around 2 μkat/1 throughout the investigation. The eAChE level at birth was 119 μkat/1 and increased slowly to a level of 145 μkat/1 at 6 months. No differences between the sexes were found. The cows suffering from parturient paresis had a pChE level of 1.80 μkat/1 ± 0.30 before treatment with calcium (Ca). The level decreased significantly (P ≦ 0.001) after Ca-infusion to a level of 1.67 ukat/1 ±0.29. Group IV had a pChE level of 1.65 μkat/1 ± 0.42 at parturition. Two to 4 months later the cows that had recovered from milk fever had a level of 1.61 μkat/1 ± 0.31 and the control cows 1.66 ukat/1 ± 0.48. No differences between the groups were found for the eAChE level. The findings show that parturition influences the pChE level in cows and that sex influences the pChE level in calves between 6 weeks to at least 6 months of age. Furthermore the elevated pChE level found in the cows suffering from parturient paresis before Ca infusion may be a further sign of a disturbance in the cholinergic system with a special preference to the neuromuscular junctions.     

Antigenic characterization of a T-CLL with heteroantisera and monoclonal antibodies: evidence for the T cell lineage of an Ia-positive, Fc-IgG--positive, suppressor-cell subpopulation

In a previous report, peripheral blood mononuclear T cells from a patient with T-chronic lymphocytic leukemia (T-CLL) were shown to bear receptors for the Fc portion of IgG (T gamma). Moreover, the ability of these cells to rosette with sheep erythrocytes was strongly inhibited by a preincubation of the cells with theophylline. These data indicated that they represent a highly purified subpopulation of Fc-IgG receptor-positive, low-affinity rosetting cells with in vitro suppressor activity on lectin-induced proliferation of normal lymphocytes. They also were reactive in antibody-dependent cell-mediated cytotoxicity but had no reactivity in natural killer cell assays. These cells were studied in this report with several heteroantisera and monoclonal antibodies. Results indicate that these T-CLL cells express a T cell antigenic pattern (OKT-3+) and the majority are Ia positive. They also react with the OKT-8 reagent (a reagent detecting the subset of T cells that contains the cytotoxic/suppressor cells), whereas they are negative with OKT-4 (which reacts with the subset of T cells that contains helper cells) and OKT-6 (thymocyte) antibodies. Heteroantisera also support the results obtained with monoclonal reagents. Despite some recent evidence showing that a high percentage of T gamma cells may belong to the monocyte-myeloid lineage, these T-CLL cells were negative with OKM-1, a monoclonal antibody reported to detect a monomyeloid antigen. These results suggest that a distinct subpopulation of suppressor T cells can be identified by membrane-marker phenotyping.     

Lack of expression on cultured human T-lymphocytes of a T-cell antigen shared by the molt-4 cell line and normal human thymocytes

Summary Four hematopoietic cell lines (CCRF-CEM, HSB-2, MOLT-4, and RPMI-8402), derived from acute lymphoblastic leukemia and expressing T-cell surface markers (T-HCL), were studied with two specific anti-T-cell sera. The sera were raised in rabbits against human thymocytes (anti-HTY) and against T-cells cultured in the presence of conditioned medium derived from lymphocytes stimulated with PHA (anti-CTC). Both sera were absorbed to obtain a T-cell specific pattern of reaction and were further absorbed with normal peripheral blood lymphocytes or with each of the four T-HCL. The anti-HTY sera absorbed with CEM, 8402, and HSB-2 still reacted with MOLT-4. A similar pattern of reactivity was found only with the anti-CTC absorbed with 8402, whereas, after absorptions with the other cell lines, this antiserum was unreactive against MOLT-4. After absorption with normal peripheral blood lymphocytes, anti-HTY still reacted with thymocytes and MOLT-4 but was negative on CTC. In contrast, anti-CTC absorbed with peripheral blood lymphocytes (PBL) was negative on thymocytes and MOLT-4 but still reacted against CTC. Our data confirm the existence of a T-cell antigen (probably an early T-cell differentiation antigen) shared between thymus and MOLT-4. This antigen is not expressed on CTC, although these cells express an antigenic pattern more complex than PBL. Antisera to CTC represents a source of anti-T-cell sera free of contamination with antibodies to early thymus-related antigens but containing other T-cell-related specificities. Supported in part by Naval Medical Research and Development Command, Research Task No. ZF51.524.013.1025, and National Cancer Institute Contract No. Y01-CB-00319. The opinions and assertions contained herein are the private ones of the writers and are not to be construed as official or reflecting the views of the Navy Department or the naval service at large. The experiments reported herein were conducted according to the principles set forth in the current edition of the “Guide for the Care and Use of Laboratory Animals,” Institute of Laboratory Animal Resources, National Research Council.