Breaking up the chromosomes of Baetica ustulata by in situ treatments with restriction endonucleases

Fixed chromosomes of Baetica ustulata were treated with restriction endonucleases and subsequently stained with either Giemsa or the DNA-specific dye propidium iodide. Each enzyme produces a specific banding pattern with both dyes, which demonstrates the value of restriction endonucleases for chromosome banding in this species. The results obtained agree with the hypothesis that the action of restriction enzymes is based on cutting and extraction of DNA and is essentially determined by DNA base composition rather than by chromatin structure. However, strictly centric bands could be an exception. At least nine chromatin types can be distinguished in B. ustulata according to their different response to enzyme digestion and to the fluorescence banding patterns. Differential digestion of specific heterochromatic areas in band 4.4 and in the supernumerary segment of M5 by the HpaII – MspI enzyme pair suggests a high level of DNA methylation at these regions. The distribution of the different classes of DNA repeated sequences in the chromosome complement of B. ustulata indicates that some bands seem to follow the general principles of heterochromatin equilocality, while conceited evolution of heterochromatic DNA in other regions might have different rates of convergence in this species.Key words: restriction endonucleases, chromatin heterogeneity, methylated bands, equilocality, concerted evolution.

Pattern of nucleolar organizer region activity during male meiosis in Callicrania seoanei (Orthoptera) as analyzed by silver staining: evidences for a possible reactivation in the period between the two meiotic divisions

Silver staining of spermatocytes and early spermatid nuclei from the neo XY race of the Tettigonioid species Callicrania seoanei reveals an active nucleolar organizer region (NOR) located proximally in a medium-sized bivalent. Ag-positive material was present at the NOR in all stages of male meiosis. However, the results obtained indicate that transcriptional activity of ribosomal cistrons (rDNA) is not maintained throughout spermatogenesis, but that NOR reactivation might occur in the period between the two meiotic divisions in addition to the more general postmeiotical reactivation in the early spermatid nuclei.

Key words: NOR activity, silver staining, male meiosis, Callicrania seoanei (Orthoptera).

Increasing verbal interaction among elderly socially isolated mentally retarded adults: a group language training procedure

The present study examined the effectiveness of a group language training procedure for directly increasing and generalizing the rate of verbal interaction among four elderly, socially isolated, moderately mentally retarded men. A withdrawal of treatment design was used to examine the effect of the procedure that used verbal prompts. behavioral rehearsal, and contingent social praise. Changes in behavior were examined in two generalization settings, one similar to the training environment (Generalization I) and the other arranged as part of the subjects' daily routine (Generalization II). Baseline data indicated no verbal interaction among the subjects. During treatment the training procedure increased the rate of subjects' verbal interactions not only in the training situation, but also in the two generalization settings. An analysis of the data obtained during the Generalization II situation indicated that subjects' verbal interaction increased not only among themselves, but with nonsubject peers present in this setting. Follow-up data showed that increases in rates of verbal interaction were maintained four months after the cessation of training. The implications of the results for program generalization and work with the language deficient individual is discussed.

Nonspecific suppressor cell function in atopic subjects

The status of concanavalin A (Con A)--nonspecific suppressor cell function and histamine-receptor--carrying mononuclear cells in 19 allergic and 27 nonallergic individuals was investigated. No differences were detected between the two groups with respect to suppression by Con A--activated suppressor cells of polyvalent Ig biosynthesis, IgG secretion, or mitogen-induced proliferative responses. Histamine-receptor--carrying cells of the allergic subjects were numerically equal to those of the nonallergic subjects. Mononuclear cells from the allergic group, however, required a higher dose of histamine than did those for the nonallergic group to induce suppression in vitro (p less than 0.02 for 10(-4) M histamine and p less than 0.05 for 10(-3) M histamine). Plasma from the allergic group contained higher levels of histamine activity (p less than 0.05). Plasma from either allergic or normal groups did not affect histamine activity in vitro. There are no apparent functional abnormalities of antigen-nonspecific mononuclear cells in the allergic patients with respect to non--IgE-mediated in vitro parameters. The demonstrated dysfunction of histamine-receptor--carrying cells could be attributed to high levels of circulating histamine that could result in receptor modulation in vivo. More work is needed to clarify the status of antigen-nonspecific and antigen-specific suppressor cells that regulate IgE biosynthesis in allergic states.

Effective treatment for rhinopulmonary mucormycosis in a boy with leukaemia

Lymphoblastic leukaemia in a 3-year-old child was complicated by rhinopulmonary mucormycosis. This was successfully treated by surgical resection of the nasal mass, pulmonary lobectomy, combined with amphotericin.

[Parachute tricuspid valve associated with Fallot's tetralogy]

Parachute deformity of the tricuspid valve was observed with a severe form of Fallot's Tetralogy with pulmonary atresia in a newborn. Signs of tricuspid stenosis (peripheral oedema, right atrial dilatation, hepatomegaly and conduction defects) were associated with the clinical signs of the principal malformation (severe hypoxaemia). To our knowledge, this is the first reported case of parachute deformity of the tricuspid valve.