Temporal relation of antigenaemia and loss of antibodies to core antigens to development of clinical disease in HIV infection.

A total of 276 sequential serum samples from 34 men with antibodies to the human immunodeficiency virus (HIV) followed up for two to seven years were analysed for HIV antigen and antibodies to the viral core and envelope proteins. Results were correlated with clinical outcome and CD4 T lymphocyte count. Both antigenaemia and the disappearance of antibodies to the core protein were associated with development of the acquired immune deficiency syndrome (AIDS) or AIDS related complex and depletion of CD4 cells. Thus AIDS or AIDS related complex developed in eight out of 16 patients with antigenaemia compared with one out of 18 patients without antigenaemia. Low counts of CD4 cells (less than 0.5 X 10(9)/l) were found in 14 of the 16 patients with antigenaemia and five of the 18 without antigenaemia. Nine patients seroconverted to HIV during the study; two of these developed antigenaemia 14 and 16 months after the estimated time of seroconversion. These results show that the late stages of HIV infection are characterised by increased production of antigen and a decrease in antibodies directed against the core protein. Antigenaemia indicates a poor prognosis; and as the antigen test is simple to do and interpret, it may therefore be useful for selecting patients for antiviral treatment.     

Apnoeic episodes induced by smothering: two cases identified by covert video surveillance.

Recurrent cyanotic episodes associated on some occasions with loss of consciousness due to cerebral hypoxia were investigated by long term tape recordings of breathing activity, oxygen saturation, air flow, electrocardiographic activity, and in some cases electroencephalographic activity. In 51 infants and children the mechanisms for the cyanotic episodes were identified (prolonged expiratory apnoea in 45, sleep related airway obstruction in three, seizure induced apnoea in one, behaviour induced apnoea in one). In one child apnoea was suspected as being caused by suffocation (smothering) by the mother. This was confirmed after enlisting the help of the police, who undertook covert video surveillance during cyanotic episodes. Each cyanotic episode was associated with a pattern of disturbance on the multichannel tape recordings which may be pathognomonic of this type of apnoea. A second infant with cyanotic episodes in whom smothering was suspected was referred for similar investigation after the availability of video recordings became established. Maternal smothering was again supported by specific patterns on multichannel tape recordings and confirmed by video surveillance. Diagnosis by video surveillance produces unequivocal evidence in these cases and avoids the need for medical and nursing staff to confront the mother with a possibly incorrect suspicion or in a court of law.     

Analysis of sister-chromatid exchanges, cell kinetics and mitotic index in lymphocytes of smoking pesticide sprayers

Whole blood of 50 smokers who were exposed to pesticides was set up in RPMI 1640 medium, and observed for sister-chromatid exchanges (SCEs), cell kinetics (CK) and mitotic index (MI). As controls, blood samples were collected from 20 non-smokers (control I) and 27 smokers (control II) who were not exposed to pesticides. A significant increase in SCEs was observed as the duration of exposure increased. The frequency of M1 metaphases increased significantly whereas M2 and M3+ metaphases decreased in the exposed group. The mitotic index increased in control II and in the exposed population while it showed a decrease at 11-25 years' exposure.     

Purification and characterization of DNA-dependent DNA-polymerase alpha from human placenta

A preparation of human placenta DNA polymerase with specific activity 6000 unit/mg was obtained. The protocol of the enzyme purification includes the crude extract preparation, the subsequent chromatographies on phosphocellulose, red sepharose, DEAE sepharose and hydroxylapatite. The isolated DNA polymerase belongs to alpha-type according to the large molecular mass (greater than 150 kDa), high sensitivity to N-ethylmaleimide, the profound inhibition of DNA polymerization activity by 200 mM KCl and the ability to catalyze DNA synthesis, using the deoxyribonucleic template and ribonucleic primer. The DNA polymerase preparations contain a few forms with Stokes radii 50-60 A and sedimentation coefficients 7.3-9.0 S as found from data of gel-filtration and ultracentrifugation in glycerol density gradient, accordingly. The existence of four various forms of DNA polymerase activity: 150, 170, 220, 480 kDa were revealed by native electrophoresis. The four steps of purification result in DNA polymerase preparation that was shown by electrophoresis to contain 15-20% of protein possessing the polymerase activity. However the preparation obtained seems to be a "chromatographically pure substance", according to following ion-exchange and affinity chromatographies. The other proteins without polymerase activity are suggested to be the components of the replicative complex of human placenta cells.     

Comparison of the catalytic and structural properties of Ca2+-ATPase in longitudinal tubules and terminal cisternae of the sarcoplasmic reticulum

The catalytic behavior and structural features of Ca2+-ATPase in the vesicles of longitudinal tubules and terminal cisternae of the sarcoplasmic reticulum isolated from rabbit skeletal muscles was analysed. pH measurements have shown under optimal conditions Ca2+-ATPase has similar catalytic behavior both in the fractions of longitudinal tubules and terminal cisternae. Under non-optimal conditions, the behavior similarity was not observed. The specific activity of the ATPase enzyme under optimal conditions was shown to be much higher in the fraction of longitudinal tubules than in the fraction of terminal cisternae. Caffeine added to both fractions had no effect on the catalytic behavior of Ca2+-ATPase. As judged from fluorescence analysis, the structure of Ca2+-ATPase of longitudinal tubules differs from that structure of terminal cisternae. In sarcoplasmic reticulum membrane, at least half of the tryptophan residues of Ca2+-ATPase was shown to be buried in the lipid bilayer. Our findings suggest that in terminal cisternae some of the Ca2+-ATPase molecules exist as an oligomeric protein and do not participate in ATP hydrolysis (named "silent" Ca2+-ATPase).     

Antigenic determinants of the constant region of human immunoglobin kappa-chain detected by monoclonal antibodies

Ten different monoclonal antibody (monAB) preparations reacting with human IgL chains of the kappa type have been obtained. Nine of the monAB interacted with the kappa-chain C domain, whereas only one monAB reacted with the V domain. It has been determined that monAB against the C domain react with three different epitopes. One epitope is expressed on intact Ig molecules as well as on isolated kappa-chains, whereas the other two epitopes are found only on isolated kappa-chains. The expression of these epitopes in 40 different myeloma kappa-chain preparations belonging to four various subgroups was studied. The level of this C domain epitope expression has been shown to depend on the variable subgroups of kappa-chains indicating a close association between V and C domains. This association leads to the alteration of antigenic activity of some C domain epitopes. The alterations are thought to be local because, as a rule, they involve only one of the three epitopes.     

Cotranscription of the S10- and spc-like operons in spinach chloroplasts and identification of three of their gene products

The organisation and expression of the rpl22, rps3, rpl16 and rpl14 genes, which belong to the S10- and spc-like operons of spinach chloroplasts, have been studied. Northern experiments and nuclease S1 mapping show that the two operon-like groups of genes are cotranscribed. It is demonstrated that the intron-containing rpl16 gene is spliced in vivo. Based on amino acid composition and protein sequence data, the products of the rpl22, rpl16 and rpl14 genes are identified respectively as the spinach chloroplast ribosomal proteins CS-L13, CS-L24 and CS-L29. The rpl22 gene product is a 5S rRNA binding protein and therefore is distinguishable from the homologous Escherichia coli L22 ribosomal protein.     

The effect of initial bioenergetic state on the cryostability of yeast cells

The cryostability of Saccharomyces cerevisiae cells decreased when they were cultivated under anaerobic conditions in a liquid growth medium YEPD as compared to the culture grown under aerobic conditions. The effect of cultivation conditions on the different cryostability of S. cerevisiae cells is discussed. The initial state of their bioenergetics was shown to influence the cryostability of yeast cells.     

The study of the growth of tylosin producer using differential centrifugation of mycelium in a sucrose density gradient

The mycelium of Streptomyces fradiae was fractionated by differential centrifugation in a sucrose density gradient (SDG) using various samples of the inoculation material and aliquots of the cultural broth taken in the course of tylosin production. The mode of mycelium distribution in SDG made it possible to select the most active inoculation material. The mycelium was redistributed from sucrose layers with a high density to those with a lower density in the course of fermentation. The fractions differed in the antibiotic activity but none of them had an activity higher than in the control centrifuged in 30% sucrose and washed off just like the fractions. Therefore, mycelium fractionation in SDG would not elevate its antibiotic activity. The paper presents the cytological characteristics of different fractions changing in the course of fermentation.     

Sensitivity of Escherichia coli cell membranes to various classes of detergents

The mechanisms of interaction between non-ionic or cationic surfactants with Escherichia coli K-12 cell membranes were studied using an approach based on the registration of changes in the membrane permeability to ethidium bromide, a fluorescent dye for nucleic acids. Triton X-100, a non-ionic detergent, was shown to exert no effect on the permeability of intact cell membranes. Triton X-100 interacted with the bacteria only after treatment with EDTA, a complexing agent for bivalent cations. Cetyltrimethyl ammonium bromide increased the permeability to ethidium bromide and the action of this cationic detergent did not require the pretreatment with the complexing agent. SDS, an anionic detergent, damaged E. coli K-12 and this could be registered by the lowering of intensity of light scattering by the bacterial suspension. The surface charge of E. coli K-12 cells was shown to influence the interaction of ionic detergents with bacterial cell membranes. Its variation by changing the pH of the incubation medium did not make E. coli K-12 sensitive to Triton X-100.