Cloning and nucleotide sequence of mouse immunoglobulin epsilon chain cDNA

cDNA corresponding to mouse IgE heavy (epsilon) chain mRNA was cloned from mouse IgE-secreting hybridoma cells. A clone containing the epsilon cDNA insert was identified by hybridization to epsilon mRNA and subsequent translation in vitro to unprocessed epsilon chain reactive with anti-mouse IgE antibodies. This clone was used to select 20 other epsilon cDNA clones by colony hybridization. The clone containing the longest insert was selected and the epsilon cDNA insert was subjected to sequence analysis. The determined sequence is 1,279 nucleotides long and contains the coding regions for part of the constant region (C epsilon) I and all of the C epsilon 2, C epsilon 3, and C epsilon 4 domains and also the entire 3' untranslated region of epsilon mRNA. When the amino acid sequence determined from the nucleotide sequence is compared to that of human epsilon chain, significant homologies between corresponding domains of the two epsilon chains are found, including conservations in cysteine and tryptophan residues and carbohydrate attachment sites.     

The interaction of 5 KeV electrons with polymers of methyl isopropenyl ketone

Poly(methyl isopropenyl ketone) (PMIPK) degrades upon exposure to 5 keV electrons. Using a scanning electron microscope to expose fine-line raster patterns in thin films of this polymer and subsequently solvent-developing the thus-degraded regions, sharp walled troughs are observed, the width of which is a measure of the sensitivity to degradation. Copolymers with several vinyl monomers were prepared and the sensitivities of these were similarly determined. Information relevant to the mechanism of depolymerization was obtained by comparing homopolymers with copolymers and by the use of additives in the irradiated polymer films. Examples of potential device-fabrication techniques using PMIPK resist are given.     

The nutritional status of patients with an alcohol problem

73 patients with an alcohol problem seen in a hospital medical unit over a two year period were examined specifically for signs suggestive of nutritional deficiency and of organ or system damage due to alcohol. A seven day dietary recall was carried out on most of them. Clinical signs of nutritional deficiency were relatively uncommon but nine patients had Wernicke-Korsakoff syndrome and ten had peripheral neuropathy. Thiamine was present in less than recommended amounts in 81.5% of the diets. Vitamin D and vitamin C were the next most common dietary deficiencies. 66.1% were deficient in energy intake and about a third of patients derived more than 40% of their energy from alcohol.     

Age-related changes in responsiveness of various rat tissue lymphocytes to mitogens

The effect of age on the mitogen responses of rat lymphoid tissues was investigated. Evaluation was based on using the in vitro proliferative response of lymphocytes from various tissues of Fischer-344 rats (2, 7, 13, 19 and 25 months) using concanavalin A (Con A), phytohemagglutinin-P (PHA-P), pokeweed mitogen (PWM) and Mycoplasma neurolyticum. The stimulation index (S.I.) for cervical, mesenteric, thymic and splenic lymphocytes treated with Con A and PHA-P was greatest for 2-month-old rats and lowest for 19-month-old rats; however, no age-related change was observed with either PWM or M. neurolyticum. The levels of mitogenic responses for lymph nodes in the two different anatomical sites paralleled one another, with the cervical lymphocytes showing a greater response. The splenic lymphocytes responded less than either lymph node lymphocyte population. When PHA-P treatment of splenic lymphocytes followed the removal of the plastic adherent population, the S. I. of the resulting non-adherent population was comparable to the S. I. of other tissue lymphocytes; however, an age-related decrease was still observed. The PHA-P proliferative response of either the 7- or 19-month non-adherent population was suppressed by the 7-month adherent population and not by the 19-month adherent population i.e., adherent population interaction with non-adherent population decreases with age.