Effect of hyperthermia on the immune response of normal rabbits

Sequential skin responses to dinitrochlorobenzene challenge and repeat assays of serum antibody titer after two injections of bovine serum albumin were used as functional indices of cellular and humoral immunocompetence following hyperthermia in normal adult New Zealand White rabbits. The animals were subjected to different degrees of local hyperthermia by watercuff or radio-frequency heating of the normal thigh muscles maintained at 42 degrees for 1 hr on 3 consecutive days or 47--50 degrees for 30 min, respectively, or to total body hyperthermia (42 degrees for 1 hr on three occasions) in a humidified incubator. No alteration occurred in the response of heated rabbits to dinitrochlorobenzene challenge over a 3-month period. The humoral immune response to bovine serum albumin was significantly depressed (p less than 0.02) in the treated animals, and the reduction was independent of method and degree of heating. The results suggest that the B-lymphocytes are more susceptible to hyperthermic damage than is the T-cell population.

The XYY genotype

The epidemiological data pertaining to the XYY genotype suggest that there is a three- to fourfold overrepresentation of XYY individuals in mental and penal settings and a twentyfold overrepresentation of mental-penal (special security) settings. The reasons behind the risk for behavioral disability are not known at this time. Tallness and ondulocystic acne are reported frequently to be associated with the genotype. Since much of the available information about the XYY sex chromosome complement is biased, more data is required before definitive statements can be made about the personality characteristics or intelligence of the vast majority of XYY men not appearing in social settings oriented towards behavioral deviancy.

Dissolution of two-component solids

The dissolution rates of compressed two-component mixtures were investigated. A good correlation between the composition of the solid and its observed dissolution rate was demonstrated by regression analysis. A model for dissolution was applied to compressed mixtures of aspirin-salicylic acid, aspirin-phenacetin, phenacetin-caffeine, and aspirin and caffeine (the last mixture complexes in solution).

Dangerousness and civil commitment of the mentally ill: some public policy considerations

The author discusses "dangerousness to others" as a ground for involuntary civil commitment of the mentally ill, suggesting that there is often a confounding of legal/public-policy concerns and mental health concerns in issues related to this concept. The questionable nature of the presumption of dangerousness in mental patients and the overprediction of dangerous behavior for this group indicate that such commitment processes may circumvent legal safeguards designed to ensure due process. The author recommends that psychiatrists and other mental health professionals assume greater responsibility for the ways in which their services are used in these proceedings.

[Current developments in genetics and their implications concerning the problems of social deviations]

A review of historical developments in the field of human genetics reveals much conflict between those espousing and hereditarian position and those maintaining an environmentalist point of view. A confusion of political, propaganda, and ideological objectives with those of science has had deleterious effects on the field of human genetics, and upon the willingness of some disciplines to accept genetic contributions to the understanding of human behavior. Modern thinking in behavioral genetics rejects the Nature-Nurture dichotomy as incorrect and meaningless. The phenotype cannot be inherited; it develops as a function of interactions between the genotype and the environment. It is convenient to think of hereditary contributions to behavioral traits as fixing a reaction range; the genotype may be viewed as determining an indefinite but nevertheless circumscribed assortment of phenotypes. There have been numerous studies seeking to ascertain the genetic factors in a variety of mental disorders. The mental disorder most thoroughly studied from a genetic standpoint is schizophrenia. Three recent studies of adoptees, two in Denmark and one in America, have indicated the importance of hereditary factors in schizophrenia. Biological relatives of adoptees diagnosed as schizophrenic were more likely themselves to have suffered schizophrenic-spectrum disorders than were biological relatives of non-schizophrenic adoptees. Adoptees whose biological parents were schizophrenic or manic depressive were more likely to themselves be diagnosed schizophrenic than were adoptees whose biological parents had no psychiatric history. Children born to hospitalized schizophrenic women and who were placed for adoption shortly after birth were more likely to be schizophrenic than were matched control adoptees born to non-schizophrenic mothers. In studies conducted in Denmark, Schulsinger has also employed the adoptee method in studies of psychopathy. Diagnostic criteria were developed to reliably identify 57 cases of psychopathy from among 507 adoptees with known mental disorders. A non-psychopathic group of matched control adoptees was also formed. Mental illness among the relatives of these adoptee cases (biological and adoptive relatives) was ascertained through a careful search of psychiatric records. Psychopathic spectrum disorders were found to be more than twice as prevalent among biological relatives of the psychopathic index cases than was the case for biological relatives of the control cases. The percentage of affected cases among adoptive relatives was nearly equal for both study groups. Thus, this study provides a demonstration of the possible importance of genetic factors in the etiology of psychopathy. Other attempts to assess hereditary and constitutional aspects of criminal behavior have been made. These include twin studies and also Eysenck's study of the heritability of behavioral traits including extraversion, introversion, and emotionality.

The molecular basis for biological inactivation of nucleic acids. The action of methylating agents on the ribonucleic acid-containing bacteriophage R17

1. The inactivation of an RNA-containing bacteriophage after reaction with four methylating agents was studied. Measurements of the extent of methylation of the RNA and of the nature and amounts of the various reaction products were made. In experiments with dimethyl sulphate and methyl methanesulphonate inactivation can be quantitatively accounted for by methylation at two of the positions involved in hydrogen bonding: N-1 of adenine and N-3 of cytosine. In experiments with N-methyl-N-nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine methylation at N-1 of adenine and N-3 of cytosine accounts for only about one-half of the observed inactivation. Scission of the RNA chain during reaction accounts for a further 20% of the inactivation. To account for the remainder it seems necessary to postulate that formation of O(6)-methylguanine constitutes a lethal lesion. 2. Breaks in the RNA chain formed on reaction with the nitroso derivatives presumably result from methylation of the phosphate diester group followed by hydrolysis of the unstable triester thus formed.

Cellular reactions of O6-methylguanine, a product of some alkylating carcinogens

Cultures of a purine-requiring mutant of Chinese hamster ovary cells (CHO-104b), randomly bred hamster embryo cells, or Escherichia coli B(s-1) were treated with non-toxic doses of (3)H-labelled O(6)-methylguanine. DNA and RNA were isolated and subjected to enzymic digestion to nucleosides at pH8. The products of digestion were analysed by ion-exchange chromatography on columns of Dowex 50 (NH(4) (+) form) at pH8.9. No (3)H-labelled O(6)-methylguanosine was detected in nucleic acid digests. (3)H-labelled O(6)-methylguanine was O-demethylated yielding [(3)H]guanine in CHO-104b cells. Radioactivity in nucleic acid digests was associated with thymidine, guanosine, deoxyguanosine and an unidentified early-eluting product. Reports of similar unidentified products from nucleic acids labelled with various agents are discussed.

Reaction products from N-methyl-N-nitrosourea and deoxyribonucleic acid containing thymidine residues. Synthesis and identification of a new methylation product, O4-methylthymidine

1. DNA was treated with N-methyl-N-nitrosourea at pH7-8, 37 degrees C, degraded to yield 3- and 7-methylpurines and deoxyribonucleosides and the reaction products were separated by chromatography on ion-exchange resins. The following methods for identification and determination of products were used: with unlabelled N-methyl-N-nitrosourea, u.v. absorption; use of methyl-(14)C-labelled N-methyl-N-nitrosourea and use of [(14)C]thymine-labelled DNA. 2. The synthesis of O(4)-methylthymidine and its identification by u.v. and mass spectroscopy are reported. 3. 3-Methylthymidine and O(4)-methylthymidine were found as methylation products from N-methyl-N-nitrosourea with thymidine and with DNA, in relatively small yields. Unidentified products containing thymine were found in enzymic digests of N-methyl-N-nitrosourea-treated DNA, which may be phosphotriesters. 4. The possible role of formation of methylthymines in mutagenesis by N-methyl-N-nitrosourea is discussed.

Differences in the patterns of methylation in rat liver ribosomal ribonucleic acid after reaction in vivo with methyl methanesulphonate and NN-dimethylnitrosamine

1. rRNA was isolated from rat liver at short intervals after the intraperitoneal injection of [(14)C]methyl methanesulphonate (50mg/kg) or NN-di[(14)C]methylnitrosamine (2mg/kg). These doses were chosen to minimize the effects of toxicity. 2. The following methods of hydrolysis of [(14)C]methylated rRNA were employed: enzymic digestion to nucleosides at pH8; alkaline hydrolysis and conversion into nucleosides; acid hydrolysis to bases. 3. The methylation products were analysed by chromatography on columns of Dowex-50 (H(+) form) and Dowex-50 (NH(4) (+) form). 4. With both methylating agents the principal product of methylation was 7-methylguanine. Differences were obtained, however, in the molar proportions of the minor bases 3-methylcytosine, 1-methyladenine and 7-methyladenine. Methylation at the O-6 position of guanine was a significant feature of rRNA obtained from the NN-di[(14)C]methylnitrosamine-treated animals but was not detected in rRNA after treatment with [(14)C]methyl methanesulphonate.

Biomethylation of deoxyribonucleic acid in cultured human tumour cells (HeLa). Methylated bases other than 5-methylcytosine not detected

1. Incorporation of methyl groups from [methyl-(14)C]methionine into DNA of dividing HeLa cells was investigated, essentially by the procedures of Culp, et al. (1970). 2. Contrary to the report of the latter, but in agreement with other work on biomethylation of mammalian DNA, 5-methylcytosine was the sole methylated base detected. 3. Chromatographic separations of 3-methylcytosine from 5-methylcytosine and purines are discussed.

Methylation of ribonucleic acid by the carcinogens dimethyl sulphate, N-methyl-N-nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine. Comparisons of chemical analyses at the nucleoside and base levels

1. The following methods for hydrolysis of methyl-(14)C-labelled RNA, and for chromatographic isolation and determination of the products, were investigated: enzymic digestion to nucleosides at pH6 or 8; alkaline hydrolysis and conversion into nucleosides; hydrolysis by acid to pyrimidine nucleotides and purine bases, or completely to bases; chromatography on Dowex 50 (NH(4) (+) form) at pH6 or 8.9, or on Dowex 50 (H(+) form), or on Sephadex G-10. 2. The suitability of the various methods for determination of methylation products was assessed. The principal product, 7-methylguanosine, was unstable under the conditions used for determinations of nucleosides. 3- and 7-Methyladenine and 3- and 7-methylguanine are best determined as bases; 1-methyladenine and 3-methylcytosine can be isolated as either nucleosides or bases; O(6)-methylguanine is unstable under the acid hydrolysis conditions used and can be determined as the nucleoside; 3-methyluracil was detected, but may be derived from methylation of the ionized form of uracil. 3. Differences between the patterns of methylation of RNA and homopolyribonucleotides by the N-methyl-N-nitroso compounds and dimethyl sulphate were found: the nitroso compounds were able to methylate O-6 of guanine, were relatively more reactive at N-7 of adenine and probably at N-3 of guanine, but less reactive at N-1 of adenine, N-3 of cytosine and probably at N-3 of uridine. They probably reacted more with the ribose-phosphate chain, but no products from this were identified. 4. The possible influences of these differences on biological action of the methylating agents is discussed. Nitroso compounds may differ principally in their ability to induce miscoding in the Watson-Crick sense by reaction at O-6 of guanine. Both types of agent may induce miscoding to a lesser extent through methylation at N-3 of guanine; both can methylate N atoms, presumably preventing Watson-Crick hydrogen-bonding. N-Methyl-N-nitrosourea can degrade RNA, possibly through phosphotriester formation, but this mechanism is not proven.