Immunological analysis of histone H2A from the slime mold Physarum polycephalum

Specific antibodies against the histone H2A from calf thymus were generated by injecting rabbits with complexes: histone H2A-RNA with a protein to RNA ratio of 3:1. In the microcomplement fixation assay the antibodies against the histone H2A from calf thymus immuno-reacted with the histone H2A from calf thymus but not with H2A from Physarum polycephalum. The histone H2A from calf thymus therefore appears to have an immunological determinant(s) which does not exist in H2A from Physarum polycephalum.     

The value of provoked expectoration in obtaining sputum samples for cytologic investigation. A prospective, consecutive and controlled investigation of 134 patients

A prospective controlled investigation in 134 consecutive outpatients compared the cytologic adequacy of sputum samples obtained by spontaneous and provoked expectoration. Inhalation of nebulized 10% sodium chloride was used for provoked expectoration. A significantly higher number of adequate samples was produced after provocation, as judged by the presence of alveolar macrophages (X2 = 5.63; p less than 0.02). The improvement in sample adequacy was limited to the nonsmokers and ex-smokers in the study. This result, together with the relatively high cost of cytologic sputum examinations, indicates that provoked expectoration should at least be applied to the collection of sputum samples from nonsmokers and ex-smokers.     

The vascularization of the menisci. Morphological basis for the repair

Degeneration of the knee joint and increase of anterior-posterior tibial displacement are resulting from total meniscectomy, especially in knees with anterior cruciate deficiency. Vascularisation of the meniscus was studied in 12 cadaver knees after latex injection of vessels. Vascularisation of the anterior and posterior horns was found to be much better than that of the body of meniscus. All vessels originated from the popliteal artery, but variably in importance, and formed the perimeniscal and subsynovial network. 11 peripheral meniscus tears (8 freshly injured, 3 ruptures older than 2 months) were repaired by refixation, followed by immobilisation for 6 weeks. Arthroscopy 3 months postoperatively showed complete healing of all tears. Clinical examinations--follow-up for 14 months--showed no signs of rerupture in any of the patients.     

Differential Adhesion and Infection of Nematodes by the Endoparasitic Fungus Meria coniospora (Deuteromycetes)

The conidia of the endoparasitic fungus Meria coniospora (Deuteromycetes) had different patterns of adhesion to the cuticles of the several nematode species tested; adhesion in some species was only to the head and tail regions, on others over the entire cuticle, whereas on others there was a complete lack of adhesion. After adhesion, the fungus usually infected the nematode. However, adhesion to third-stage larvae of five animal parasitic nematodes, all of which carry the cast cuticle from the previous molt, did not result in infection. M. coniospora infected animal parasitic nematodes when this protective sheath was removed. Seven preparations of sialic acid (N-acetylneuraminic acid) gave three types of response in adhesion-infection of nematodes: (i) a significant reduction in conidial adhesions; (ii) no interference with adhesion, but a 10-day delay in infection; and (iii) a delay in infection by 2 to 3 days. The current results support previous findings indicating involvement of sialic acids localized on nematode cuticles in recognition of prey by M. coniospora.     

Trends in economic traits, halothane sensitivity, blood group and enzyme systems of Swiss Landrace and Large White pigs

Pigs deriving from 150 breeding centres constituting a representative section of elite breeding herds (2496 Swiss Landrace pigs, 587 Swiss Large White pigs) were subjected to blood typing during the period 1981 to 1984. Production traits such as daily gain, feed conversion ratio, lean meat content and meat quality score were available to show the trend in these performance traits since 1978. Field data on the halothane reaction of 14 270 Swiss Landrace (SL) pigs were used to assess the porcine stress syndrome during the period 1978-1983. In SL pigs the frequency of the alleles Ha, PhiB and AdaA decreased significantly, and that of the Hc and PhiA increased during the period of the study. The frequency of the Ha allele dropped from 0.36 in 1981 to 0.20 in 1984, whereas the Hc allele rose from 0.22 to 0.37. In Swiss Large White (SLW) pigs, on the other hand, the frequency of the Ha allele increased constantly from 0.31 to 0.37 during this period. An initial frequency of 17.7% (1978) halothane reactors in SL pigs was lowered to 0.7% (1982) after five years of halothane testing. In SL pigs the meat quality scores improved regularly, whereas in SLW pigs it did not change very much. The percentage of PSE animals in the SL breed was reduced from 32.7% in 1978 to 7.1% in 1983. Because the Hal locus is associated with production traits such as meat quality, linkage disequilibria could explain the observed associations between the H and Phi types and production traits.     

Limited nonenzymatic glucosylation of low-density lipoprotein does not alter its catabolism in tissue culture

This study examines the effects of various degrees of chemical modification of low-density lipoprotein (LDL) on its catabolism by various cell types. Moderate glucosylation of LDL does not alter its interaction with the high-affinity receptor present on human fibroblasts at concentration of 5-2000 micrograms LDL-cholesterol/ml. Only heavily glucosylated LDL (more than 12 lysine residues glucosylated per apolipoprotein B) or LDL glucosylated in the presence of Na(CN)BH3, i.e., conditions not expected to occur in diabetes, inhibit receptor-mediated internalisation and degradation. Moderately glucosylated LDL is also readily recognized by cultured rat hepatocytes and porcine endothelial cells. Human monocyte-derived macrophages accumulate cholesteryl ester when incubated with acetylated LDL for 12 days but no enhanced cholesteryl ester formation was found when native or glucosylated LDL (3.3 lysines glucosylated per apolipoprotein B) were used.     

A sensitive method to introduce membrane-bound proteins into recipient cells based on affinity enrichment of lipid vesicles to the recipient cell prior to fusion

A sensitive analytical procedure for studying membrane-bound structures has been developed. Membrane glycoproteins inserted into liposomes were transferred to recipient cells by use of a lectin, concanavalin A, bound to the cells as a bridge to generate proximity between the recipient cell and the glycoprotein-containing liposome, prior to exposure to the fusing agent, poly(ethylene glycol). Partially purified histocompatibility antigen from rats was introduced into the membrane of human lymphocytes. After treating the cells with poly(ethylene glycol) under fusion conditions, some of the antigen present in the preparation could not be eluted with alpha-methyl mannoside and EDTA, indicating that incorporation in the cell membrane had taken place. This antigen remained exposed on the lymphocyte surface for approximately 1 h as demonstrated by sensitivity of the lymphocytes to the lytic effect of an antiserum to the histocompatibility antigen in the presence of complement. Some of the lectin molecules seemed to be internalized in the cells but no induction of cell mitosis was observed. The described method gives an opportunity to work with small amounts of membrane proteins inserted into liposomes, introducing them into recipient cells for analysis of their biological activities.     

Chloride as allosteric effector of yeast aminopeptidase I

Activation of yeast aminopeptidase I by chloride was studied by kinetic methods. Several effects contributed to overall activity enhancement: At low concentrations of Zn2+ (an essential component of aminopeptidase I) chloride increased the amounts of active enzyme by reducing the cooperativity of metal binding. In addition, substrate turnover was enhanced due to increased kcat and a moderate decrease of Km. At high concentrations of Zn2+ substrate saturation curves were sigmoidal. Under these conditions chloride activated by restoring Michaelis-Menten kinetics of substrate turnover. At the same time, reconstitution of active enzyme from apoprotein and Zn2+ was substantially accelerated and its inactivation due to loss of Zn2+ was retarded. Co2+-Substituted aminopeptidase I, although catalytically active, was much less sensitive to chloride activation. Apparent binding constants for chloride, as estimated from its effects on metal binding and catalysis, respectively, were different. This suggests that two independent activation mechanisms may be operative. Both appear to be mediated by conformational changes of the enzyme protein.     

Changes in the mucosa of the duodenum and stomach as a result of experimental duodenal ulcers and vagotomy

By means of the transmissive and scanning electron microscopy methods and radioautography, structure of mucous membrane of the stomach and duodenum has been studied under experimentally induced duodenal ulcers before and after vagotomy during various time. The vagotomy results in accelerated healing of the ulcer defect. This is connected with an increased proliferative activity in the crypta cells, however, this is accompanied with deceleration of their differentiation. Under the duodenal ulcers the amount of chief and parietal cells increases in the gastric mucous membrane, this depends on gastrostasis produced by stenosis of the pylorus. At vagotomy the amount of the chief and parietal cells in the fundal glands of the mucous membrane decreases; this is accompanied with a lowered secretory activity.