Taste systems of the petrosal ganglion of the rat glossopharyngeal nerve

Single unit recordings were taken from sensory ganglion cellsin the petrosal ganglion (PG) of the glossopharyngeal nerveof the rat. These taste units were examined with respect tospontaneous and evoked discharge patterns and responsivenessto a wide variety of chemical compounds, most of natural occurrence.Spontaneous activity patterns, with few exceptions, tended tobe extremely irregular with both bursting (clusters of 2–3spikes) and grouping (large groups of spikes as in evoked discharges).Most interspike interval histograms of spontaneous activitywere multimodal, similar to rat geniculate ganglion (GG) units.Evoked discharges usually displayed grouping of spikes, andlong latencies of onset and persistence of discharge after rinsewere sometimes seen. Little response was shown to nucleotidesor salts. Units responsive to amino acids tended to show largedischarge to only one or two amino acids; and the most responsiveamino acid usually varied from cell to cell. Units responsiveto alkaloids only responded to a few alkaloids with atropineand quinine being the most stimulatory. Units responsive toacids only discharged to a few of the acids tested and oftenacids of low pH elicited no discharge. Saccharin activated unitsresponsive to both sugar and alkaloids. A few units highly responsiveto both sugar and alkaloids were seen. The units were placedinto four clusters on the basis of chemicals activating themand certain neurophysiological characteristics: PG salt units,PG acid units and, tentatively, amino acid (sugar) units andX (alkaloid and alkaloid plus) units. The PG salt units didnot show the exclusive sensitivity to sodium and lithium compoundsas did the GG salt units. The PG acid units could also be differentiatedfrom the GG acid units. The petrosal amino acid and X units,on the other hand, could not be differentiated from similarunits in the rat GG.     

Stereochemical effects of non-ionic methylphosphonates on nucleotide conformations.

The preferred conformations of deoxyribo and ribonucleoside 3'-methylphosphonates are analysed by minimizing the conformational energy as a function of all the major parameters including the sugar ring for both the S- and R-isomers. The results show that neither the substitution nor the nature of the diastereomer affects significantly the preferred conformations compared to the naturally occurring nucleoside 3'-phosphates. The preferred range of C3'-O3' bond torsions or the phase angles of pseudorotation (P) of the sugar are unaffected. The chiral substitution on the phosphate always adopts a conformation distal to the secondary C3' carbon atom in the minimum energy conformational state. Further, it introduces certain restrictions on the preferred range of P-O3' torsions depending on the methylphosphonate configuration. Methylphosphonate, especially the S-isomer, renders the normal gauche- range of P-O3' bond torsions responsible for the stacked helical duplexes to be energetically unfavourable besides introducing a high energy barrier between trans and gauche conformations. Therefore it is suggested that duplexes with S-methylphosphonate may favour extended phosphodiester conformations. These factors explain the observed lower melting temperature as well as the downfield shifts in the 31P signals in duplexes containing the S-isomer.     

Neurophysiology of geniculate ganglion (facial nerve) taste systems: species comparisons

On the basis of various measures taken from geniculate gangliontaste neurons in four species, it was concluded that withineach species the neurons could be subdivided into distinct functionalgroups. In this report, the neural groups of different specieswere directly compared. Units from all four species were studiedwith a common test series of solutions in addition to otherstimuli. Since these stimuli were presented at the same concentrationsto all species, direct quantitative comparisons across specieswere possible for a wide range of chemical compounds. In addition,the neural groups were compared with respect to spontaneousand evoked activity measures, latency to electrical stimulation,and receptive field characteristics. These neurophysiologicaldata suggest a basic model of four distinct subgroups: acidunits, salt units, amino acid units, and X units.     

Stereochemical studies on nucleic acid analogues. I. Conformations of alpha-nucleosides and alpha-nucleotides: interconversion of sugar puckers via O4'-exo.

The preferred conformations of ribo and deoxyribo alpha-nucleosides and alpha-nucleotides, the stereoisomers of the naturally occurring beta-isomers, are worked out by minimizing the conformational energy as a function of all the major parameters including the sugar ring conformations along the pseudorotation path. The results of the studies bring out certain distinct conformational features that are at variance with their beta counterparts. The range of glycosyl conformations are found to be not only quite restricted here but favor predominantly the anti conformation. The syn glycosyl conformation for the entire region of P values are found to be energetically less favorable, with the barrier to anti in equilibrium with syn interconversion being higher especially in alpha-ribonucleosides. The energetically preferred range of pseudorotation phase angles (P) is also considerably restricted and P values corresponding to the C1'-exo range of sugars are highly unfavorable for alpha-nucleosides, in sharp contrast to the broad range of sugar ring conformations favored by beta-isomers. While both trans congruent to 180 degrees and skew congruent to 270 degrees conformations around the C3'-O3' (phi') bond are favored for alpha-3'-nucleotides with deoxyribose sugars, ribose sugars seem to favor only the skew values of phi'. Most interestingly and in sharp contrast to beta-stereoisomers, an energy barrier is encountered at P values corresponding to O4'-endo sugars. This suggests that the possible sugar pucker interconversion between C2'-endo/C3'-exo and C3'-endo/C2'-exo in alpha-anomers could take place only through the O4'-exo region. Likewise the possible path of anti in equilibrium with syn interconversion in alpha-nucleosides is not via high anti, in sharp contrast to beta-nucleosides. These observations should be borne in mind while assigning the sugar ring conformers in alpha-nucleosides and those containing them from nmr investigations. Comparison of the results with beta-anomers seem to suggest on the whole a lack of conformational variability or the restricted nature of alpha-stereoisomers. This could be one of the reasons for its nonselection in the naturally occurring nucleic acids.     

Foliar regeneration of the endangered Red Vanda,Renanthera imschootiana Rolfe (Orchidaceae)

An in vitro method was developed to regenerate large numbers of phenotypically uniform plants from the basal parts of the leaves of flowering plants of Renanthera imschootiana Rolfe. Differentiation of up to 10 shoot buds free of callus and protocorm-like bodies occurred in 10–12 weeks from the base of a single leaf implanted in Mitra et al. (1976) medium supplemented with 2% sucrose, 2 g l^-1 peptone, 44.4 M benzyladenine (BA) and 10.7 M naphthaleneacetic acid (NAA). Subculture of the tissues in medium enriched with 10% coconut water and 35 g l^-1 ripe banana pulp resulted in the production of highest average number of 40 shoots in 12 weeks. No difference in the regeneration potential was observed among the three young leaves while mature leaves did not respond. All the leaves of the regenerated shoots were easily recultured to increase shoot multiplication. Shoots readily formed roots on transfer to a medium containing 4.4 M BA, 10.7 M NAA and 1% activated charcoal. All regenerated plants examined were normal diploids with 2n=38. Foliar meristem culture appears to have great potential for ex situ conservation and propagation of this extremely endangered orchid.Abbreviations BA benzyladenine - NAA naphthaleneacetic acid     

Didymozoid trematodes (including new genera and species) from marine fishes of the Waltair coast,Bay of Bengal

Summary Fifteen species of didymozoid trematodes are recorded form marine fishes off the Waltair coast, Bay of Bengal, India. These include three new genera, namely, Platocystoides, Indodidymozoon and Renodidymocystis and six new species, namely, Didymozoon lobatum from Euthynnus affinis, Allodidymozoon cylindricum from Sphyraena obtusata and S. picuda, A. operculare from Sphyraena obtusata and S. picuda, Indodidymozzon platycephali from Platycephalus scaber, Renodidymocystis yamagutii from Rastrelliger kanagurta and Metanematobothrioides branchialis from Pristipomoides typus. Other species reported are: Didymocystis wedli Ariola, 1902, Coeliodidymocystis kamegaii Yamaguti, 1970, Platocystoides polyaster (Job, 1962), Neometadidymozoon polymorphis (Oshmarin & Mamaev, 1963), Lobatocystis yaito Yamaguti, 1965, Metadidymozoon branchiale Yamaguti, 1970; Allonematobothrium epinepheli Yamaguti, 1965; Gonapodasmius spilonotopteri Yamaguti, 1970 and Pseudocolocyntotrema yaito Yamaguti, 1970. Two new combinations made are: Allodidymozoon apharyngi (Job, 1961) for Didymozoon apharyngi Job, 1961 and Platocystoides polyaster (Job, 1962) for Platocystis polyaster Job, 1962.     

Effect of imipramine hydrochloride on the activity of gamma-aminobutyric acid transaminase in regions of the rat brain

The effect of intraperitoneal injection of imipramine hydrochloride on the activity of gamma-aminobutyric acid transaminase was determined in three regions of the rat brain.The cerebral hemispheres did not show a significant change in the activity of gamma-aminobutyric acid transaminase. Cerebellum and brain stem, both, however, showed a very significant decrease in the activity of the enzyme at 15 and 30 minutes after drug administration. At 90 minutes after drug administration, the activity of gamma-aminobutyric acid transaminase had returned to nearly control values.     

Profiles of Serum Cytokines in Acute Drug-Induced Liver Injury and Their Prognostic Significance

Drug-induced liver injury (DILI) is the most common cause of acute liver failure in the United-States. The aim of the study was to describe serum immune profiles associated with acute DILI, to investigate whether there are profiles associated with clinical features or types of DILI and/or with prognosis, and to assess temporal changes in levels. Twenty-seven immune analytes were measured in the sera of 78 DILI subjects in the Drug-Induced Liver Injury Network (DILIN) and compared with 40 healthy controls. Immune analytes (14 cytokines, 7 chemokines and 6 growth factors) were measured by BioPlex multiplex ELISA at DILI onset and after 6 months. A modeling process utilizing immune principles was used to select a final set of variables among 27 immune analytes and several additional clinical lab values for prediction of early death (within 6 months of DILI onset). Nineteen of the 27 immune analytes were differentially expressed among healthy control, DILI onset and 6-month cohorts. Disparate patterns of immune responses, especially innate and adaptive cellular (mostly TH17) immunity were evident. Low values of four immune analytes (IL-9, IL-17, PDGF-bb and RANTES) and serum albumin are predictive of early death [PPV = 88% (95% CI, 65%-100%), NPV = 97% (95% CI, 93%-100%), accuracy = 96% (95% CI, 92%-100%)].

Conclusions

Acute DILI is associated with robust and varying immune responses. High levels of expression of cytokines associated with innate immunity are associated with a poor prognosis, whereas high levels of expression of adaptive cytokines are associated with good long-term prognosis and eventual recovery. Serum immune analyte profiles at DILI onset appear to be of prognostic, and perhaps, diagnostic significance.