An estimate of phylogenetic relationships among culicine mosquitoes using a restriction map of the rDNA cistron

Restriction maps of the rDNA cistron of twelve species of mosquitoes in six genera of the subfamily Culicinae were constructed using eight 6 bp recognition restriction enzymes. Anopheles albimanus was used as an outgroup. The size of the rDNA cistron ranged from 8.5 kb in Aedes katherinensis to 12.9 kb in Ae. polynesiensis. A total of twenty-six sites were scored; eighteen were polymorphic among ingroup taxa. The proportion of polymorphic nucleotide sites (Pnuc) was 0.059 and the heterozygosity per nucleotide site (Hnuc) was 0.028. Wagner and Fitch Parsimony, Dollo Parsimony and Nei-Li distance/neighbour-joining methods were used to construct phylogenetic trees. The rDNA RFLP dataset did not provide a well-supported phylogeny among culicine taxa. The RFLP phylogenies are incongruent with the morphology character based and molecular phylogenies and derived relationships did not correspond with current taxonomic classifications. The lack of resolution was due to homoplasy arising from frequent independent loss or gain of restriction sites among unrelated taxa.     

Cytogenetic and biochemical reactions of experimental animals to combined exposure to low-intensity radiation and chemical factors]

Combined exposure of mice to a mixture of chemicals in small quantities and gamma-radiation at a total dose of 30 sGy cause partial summation of biological effects assessed by cytogenetic disorders in nuclear cells of the bone marrow and changes in erythrocyte metabolism. The level of cytogenetic damages in bone marrow cells remained increased till day 14 of recovery, whereas following exposure to chemicals or radiation alone the number of chromosomal aberrations (ChA) was nearly same as in control at this point of recovery The anaphase method showed prevalence of ChA in the form of fragments over bridges in marrow karyocites. The combination of factors suppressed energy-producing processes in erythrocytes (reliable reductions in lactate dehydrogenase and lactate) and activated oxidation processes (reliable decrease in reduced glutathione). Functional shifts in erythrocyte metabolism persisted till day 30 of recovery Based on results of the investigation, functional status of organism following low-intensity exposures can be assessed, along with cytogenetic, also by indices of erythrocyte metabolism.     

Reaction of different functional zones in mouse thymus and spleen lymphoid tissue to γ-irradiation

It is shown that immune organs respond to single γ-radiation of 6.9 Gy in a cyclic manner. Acute reaction characterized by spontaneous lymphocyte lysis in the thymus and spleen develops on day 1 postirradiation and takes 3 and 7 days, respectively. This is followed by enhancement of thymocyte mitotic activity and migration of young cells to the thymic cortex and splenic lymphoid tissue. Twenty-one day postirradiation lymphoid cell populations in the thymus and spleen recover to 70–90 and 55–70%, respectively. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 4, pp. 381–384, April, 1998     

Dihydropyridine inhibition of neuronal calcium current and substance P release

Dihydropyridine (DHP) calcium channel antagonists, which inhibit the slowly inactivating or L-type cardiac calcium (Ca) current, have been shown to be ineffective in blocking⁴⁵Ca influx and Ca-dependent secretion in a number of neuronal preparations. In the studies reported here, however, the antagonist DHP nifedipine inhibited both the L-type Ca current and potassium-evoked substance P (SP) release from embryonic chick dorsal root ganglion (DRG) neurons. These results suggest that, in DRG neurons. Ca entry through L-type channels is critical to the control of secretion. The inhibition of Ca current by nifedipine was both voltage and time-dependent, significant effects being observed only on currents evoked from relatively positive holding potentials maintained for several seconds. As expected from these results, nifedipine failed to inhibit L-type Ca current underlying the brief plateau phase of the action potential generated from the cell's normal resting potential; likewise, no significant effect of the drug was observed on action potential-stimulated SP release evoked by electrical field stimulation. The results of this work are discussed in terms of an assessment of the role of L-type Ca channels in neurosecretion.This work was supported by United States Public Health Service Grant NS16483 (KD) and by a USPHS Postdoctoral Fellowship (SGR)     

Antibody and cellular immune responses to microfilarial antigens in ferrets experimentally infected withBrugia malayi

Eleven of 15 ferrets experimentally infected withBrugia malayi became amicrofilaremic after a brief patency; only four ferrets remained patent after 6 months of infection and two of these ferrets developed a high, persistent microfilaremia. Blastogenic responses of peripheral blood lymphocytes to antigens of microfilariae (mf), assayed in vitro, demonstrated an antigen sensitivity at prepatent, patent and postpatent periods of infection. Lymphocytes from ferrets with high microfilaremia had elevated background responses in culture which were directly correlated with the number of circulating mf. This background response was attributed to antigenic stimulation by mf present in the lymphocyte cultures; addition of mf to cultures of lymphocytes from postpatent ferrets induced responses equivalent to those observed in microfilaremic ferrets. Lymphocyte responses to the mitogen, concanavalin A, did not differ significantly among microfilaremic, amicrofilaremic and uninfected ferrets. Antibody in IgG to antigens of mf measured by ELISA and by immunoblots from SDS-PAGE showed similar patterns of response in ferrets which became amicrofilaremic and in the few ferrets which remained microfilaremic. Prausnitz-Kustner tests demonstrated no consistent differences in titers to microfilarial antigens between patent and amicrofilaremic ferrets. The results suggest a high level of immune responsiveness to antigens of mf in infected ferrets with no evidence of immunosuppression associated with prolonged microfilaremia or of major changes in immune responses with development of amicrofilaremic infections.     

Magnitude of the inflammatory response to cardiopulmonary bypass and its relation to adverse clinical outcomes

INTRODUCTION: Cardiopulmonary bypass (CPB) induces an inflammatory response believed to contribute to postoperative morbidity. We hypothesized that the magnitude of the inflammatory response following CPB would be associated with adverse clinical outcomes. METHODS: Twenty-nine patients had plasma TNF, IL-6, IL-8, elastase, histamine, complement C5a, and complement C3a measured by ELISA before, during, and after cardiac operations employing CPB. Inflammatory mediator levels were analyzed with respect to outcomes. RESULTS: Mediator levels peaked at 4 h post-CPB and either returned to baseline or substantially decreased by 24 h. Patients with peak mediator levels above the median for the group as a whole were classified as 'hyper-responders'; those with levels below the median were classified as 'normal responders'. While IL-8, C3a, and IL-6 levels were independently associated with adverse outcomes, TNF, histamine, and C5a levels were not. Elastase levels trended towards adverse outcomes. IL-8 'hyper-responders' experienced significantly greater postoperative weight gain and had higher IL-8 levels at 24 h (p<0.05), with trends towards renal impairment and protracted supplemental oxygen requirements. C3a 'hyper-responders' strongly trended towards increased bleeding, delayed extubation, greater postoperative weight gain, and decreased levels of independent functioning at discharge (p < or = 0.10). IL-6 'hyper-responders' experienced significantly more postoperative bleeding, delayed extubation, and higher IL-6 levels at 24 h compared to 'normal responders' (p < 0.05). They strongly trended towards greater postoperative weight gain and decreased levels of independent functioning at discharge (p < or = 0.10). CONCLUSIONS: Patients who have an exaggerated inflammatory response to CPB tend to bleed more, require more respiratory support, demonstrate greater capillary leak via weight gain, and display a decline in independent functioning relative to normal responders. Thus, it appears that the magnitude of the inflammatory response to CPB adversely influences clinical outcomes.     

Phase II study of intravenous melphalan (NSC-8806) in the treatment of patients with advanced squamous carcinoma of the head and neck

The Illinois Cancer Center entered 25 patients on a phase II trial of intravenous melphalan treating patients with recurrent, metastatic or locally advanced and inoperable squamous cell carcinoma of the head and neck. All patients had bi-dimensionally measurable disease, at least a sixty day life expectancy, and adequate performance status (ECOG scale 2). All patients except one had received prior radiotherapy, chemotherapy or both. Melphalan dosage was 30 mg/m² every three weeks. Twenty-four patients were evaluable for response. One patient with laryngeal carcinoma had a clinical complete response of a nodal metastasis. Four patients had stabilization of disease for one to three months. There was formidable toxicity, including neutropenia (ANC < 1000/l 36%), and thrombocytopenia (< 50,000/l 32%). There were no drug-related deaths. Melphalan administered intravenously does not appear to be efficacious therapy in patients with previously treated advanced head and neck squamous carcinomas.     

Identification of amino-terminal sequences contributing to tryptophan hydroxylase tetramer formation

Tryptophan hydroxylase (TPH) catalyzes the rate-limiting step in the biosynthesis of serotonin. In the rabbit, TPH exists as a tetramer of four identical 51-kDa subunits comprised of 444 amino acids each. The enzyme consists of an amino-terminal regulatory domain and a carboxyl-terminal catalytic domain. Previous studies demonstrated that within the carboxyl-terminus of TPH, there resides an intersubunit binding domain (a leucine zipper) that is essential for tetramer formation. However, it is hypothesized that a 4,3-hydrophobic repeat identified within the regulatory domain of TPH (residues 21–41) may also be involved in macromolecular assembly. To test this hypothesis, a series of amino-terminal deletions (NΔ15, 30, 41, and 90) were created and assessed for macromolecular structure using size-exclusion chromatography. The amino-terminal deletion NΔ15, upstream from the 4,3-hydrophobic repeat, was capable of forming tetramers. However, when a portion of the 4,3-hydrophobic repeat was deleted (NΔ30), a heterogeneous elution pattern of tetramers, dimers, and monomers was observed. Complete removal of the 4,3-hydrophobic repeat (NΔ41) rendered the enzyme incapable of forming tetramers; a monomeric form predominated. In addition, a double-point mutation (V28R-L31R) was created in the hydrophobic region of the enzyme. The introduction of two arginines (R) at positions 28 and 31 respectively, in the helix disrupted the native tetrameric state of TPH. According to size-exclusion chromatography analysis, the double-point mutant (V28R-L31R) formed dimers of 127 kDa. Thus, it is concluded that there is information within the amino-terminus that is necessary for tetramer formation of TPH. This additional intersubunit binding domain in the amino-terminus is similar to that found in the carboxyl-terminus.