Vitrectomy: a new challenge for the anesthesiologist

A new surgical procedure, virtectomy, for alleviation of blindness caused by previously intractable vitreous disease, is described. Special demands of vitrectomy upon the anesthesiologist are enumerated. Problems presented by a patient population, 83 percent of whom suffered from severe diabetes mellitus and/or hypertension with a variety of complications, are discussed. Anesthetic technic used for 47 patients undergoing vitrectomy is described.

Functional studies on chromatin

Functional studies on chromatin include assays of template activity and template capacity. Template activity is the measure of the rate of polynucleotide synthesis supported by a chromatin template in an incubation mixture including exogenous DNA-dependent RNA polymerase. It can be a highly misleading criterion unless great care is taken to standardise conditions. Template capacity is the measure of the DNA in a preparation of chromatin as compared with purified DNA, which is accessible to transcription by exogenous DNA-dependent RNA polymerase. It is determined by studying the complexity of the RNA made in the reaction, usually by RNA-DNA hybridization. The effects of different methods of preparation of chromatin, different RNA polymerases, conditions of incubation and purification of RNA are discussed.

The application of these and other methods to the study of reconstituted chromatin is described.

Regulation of acetylcholinesterase in neuroblastoma cells

The specific activity of mouse neuroblastoma acetylcholinesterase (EC 3.1.1.7) increased 25-fold when the rate of cell division was restricted. The results show that acetylcholinesterase activity is regulated in neuroblastoma cells and that the regulatory mechanism is inversely related to the rate of cell division. Under the same conditions the specific activity of catechol-O-methyl transferase (EC 2.1.1.6) did not change significantly.

Repression of colony formation reversed by antiserum to mouse thymocytes

Marrow cells derived from C57BL/6 mice form many fewer splenic colonies in irradiated C57BL/6 x C3H F1 hybrid recipients than in irradiated C57BL/6 recipients (repression of colony formation). This effect is reversed by treatment of the hybrid recipients with active antiserum to mouse thymocytes. The repression phenomenon cannot readily be explained in immunological terms; hence the effect of the antilymphocyte serum on this phenomenon may not result from immunosuppression in the usual sense.

Sensitization of guinea-pigs to measles vaccines

Attenuated measles virus vaccine of chick embryo tissue culture origin and unadsorbed inactivated measles vaccines derived from monkey kidney tissue culture produced little or no sensitization of guinea-pigs, as monitored by the Schultz–Dale or passive cutaneous anaphylaxis techniques. Inactivated vaccines of both monkey kidney and chick embryo tissue culture origins were sensitizing when they contained a mineral adjuvant. The sensitizing activity was also present in the aqueous phase of Tween 80–ether-treated measles virus fluid and in uninfected tissue cultures of simian, avian and human origins.

The antigenic loci of insulin

Insulin exhibited some cross-reactivity with the isolated S-sulfo A- and B-chains in the passive cutaneous anaphylaxis test. The synthetic peptides A1–9, A10–21, and A1–21gave a passive cutaneous anaphylactic reaction with guinea pig antiserum to natural A-chain, whereas high levels of A10–21and A1–21could also inhibit a subsequent insulin challenge from reacting with antiserum to insulin. The synthetic peptides B1–8, B9–30, B24–30, and B1–30reacted with antiserum to natural B-chain but high levels of peptides (B2–8)2, B9–14, and (B17–23)2were inactive. The symmetrical double peptide (B1–8)2reacted with guinea pig antiserum to intact insulin as well as with antiserum to B-chain and certain sera from insulin-resistant diabetic patients. The results indicated that injection of ox insulin into guinea pigs caused production of anaphylactic antibodies mainly towards antigenic loci in the regions A10–21and B1–8of the insulin molecule, whereas antigenic determinants in the regions A1–9and B24–30were less important.

Passive cutaneous anaphylaxis induced in guinea pigs by insulins and their component chains

Small amounts of purified ox insulin and its component chains provoked passive cutaneous anaphylaxis (PCA) in guinea pigs previously injected intradermally with antiserum to ox insulin. Cod insulin and its chains also yielded a PCA reaction with antiserum to cod insulin, indicating that antibody-combining sites are located on both the A- and B-chains of insulin Enzymic digestion of the chain preparations essentially destroyed their ability to combine with anaphylactic antibodies, although the B-chain digests had some residual PCA reactivity.Ox and cod insulins gave positive PCA reactions with the heterologous antiserum but at higher levels than with the homologous antiserum, and none of the four chain preparations reacted with the heterologous antiserum. These results demonstrated differences between the antibody-combining sites on the chains of ox and cod insulins.Insulins from a wide range of species also yielded a PCA reaction with antisera to cod and ox insulins, suggesting that the different hormone preparations have certain antigenic determinants in common. Immunologic relationships between several insulins were derived from the competitive inhibition of one antiserum by the other when both were present in the same animal.