Isolation, characterization, and mapping of two human potassium channels

Two novel human genes encoding putative potassium channels, kH1 and kH2, were identified from a human fetal brain cDNA library. Sequence analysis showed that kH1 and kH2 are homologous to rat IK8 and rat K13, respectively. The kH1 encodes a polypeptide of 495 amino acids, which shares 88% and 95% identity to IK8 at the nucleotide and amino acid level, respectively. The kH2 encodes a polypeptide of 515 amino acids with 86% and 92% identity to K13 at the nucleotide and amino acid level, respectively. Northern blot studies revealed that one mRNA species, approximately 5kb, of the kH1 was expressed abundantly in tissues examined, including the heart, skeletal muscle, and less abundant in the brain, liver, kidney, and pancreas. Interestingly, an alternative spliced form of 2.4 kb mRNA species of the kH1 was also found in the brain. Unlike kH1, 2.4 kb of kH2 was expressed predominantly in the brain, placenta, and the skeletal muscle where it shared a differently spliced form of the kH2 mRNA, approximately 2.0 kb. Fluorescence in situ hybridization localized kH1 to the human chromosome 2p25 and kH2 to the human chromosome 20q13.

[Acupuncture and cortical evoked potentials]

Research works for the effects of acupuncture on cortical evoked potentials were reviewed since 1970 in this article. As a result of the acupuncture anesthesia being applied widely in clinical operation, most of the studies were focused on the evoked potential of somatosensory cortex for elucidating the principle of the analgesic effect of acupuncture, while less observations were reported on the aspects of auditory and visual cortex. The amplitude of the evoked potential was often used as an index in assessing the excitability of the cerebral cortex in the studies of the effect of acupuncture in the past. An increase in the amplitude of evoked potential means an excitory process of the cortex and a decrease means depression. Based on their work, the authors consider that whether the change in the amplitude of cortical evoked potential could be served as an optional index in reflecting the excitability of the cortex is still a problem in neurophysiology remained for further investigation.

[Effects of calcium channel blockers and calmodulin inhibitors on the secretion of endothelin-1 in cultured endothelial cells]

OBJECTIVE

The study is to investigate the effects of calcium channel blockers and calmodulin inhibitors on the secretion of endothelin-1 (ET-1) in cultured endothelial cells from human umbilical veins.

RESULTS

Results showed that calcium channel blockers verapamil (5.5 x 10(-6) mol/L, 5.5 x 10(-5) mol/L), diltiazen (2.4 x 10(-4) mol/L) and calmodulin inhibitors chlorpromazine (3.1 x 10(-5) mol/L, 3.1 x 10(-4) mol/L), berbamine (1.6 x 10(-5) mol/L, 1.6 x 10(-4) mol/L) significantly decreased medium ET-1 levels in cultured endothelial cells.

CONCLUSION

It was also indicated that extracellular calcium influx and calmodulin activity were necessary to the secretion of ET-1. In addition, nitroglycerine (2.2 x 10(-3) mol/L) remarkably reduced medium ET-1 levels in cultured endothelial cells, which suggested that nitric oxide might inhibit the secretion of ET-1.

Identification of cytochrome P4503A as the major enzyme sub-family responsible for the metabolism of 22,23-dihydro-13-O-[(2-methoxyethoxy)methyl]-avermectin B1 aglycone by rat liver microsomes

1. Metabolism of 22,23-dihydro-13-O-[(2-methoxyethoxy)methyl]-avermectin B1 aglycone (MEM-H2B1), a new avermectin, by rat liver microsomes has been studied. Metabolites identified were formed by demethylation of the methoxyethoxymethoxy (MEM) side chain, loss of the MEM side chain, partial cleavage and further oxidation of the MEM side chain, and oxidation of the aglycone after cleavage of the MEM side chain. 2. The specific cytochrome P450 isoforms involved in the metabolism of MEM-H2B1 were identified through immunoinhibition studies. Among several antibodies prepared against various cytochrome P450s, only anti-rat P4503A IgG inhibited MEM-H2B1 metabolism by liver microsomes from the untreated rat. Moreover, troleandomycin, a selective suicide inhibitor for enzymes of the cytochrome P4503A family, inhibited the total metabolism by > 80%. These results clearly indicate that cytochrome P4503A is primarily responsible for the metabolism of MEM-H2B1. 3. Secondary metabolism was evident in the metabolism of MEM-H2B1 by dexamethasone and phenobarbital induced liver microsomes, where different isoform(s) of cytochrome P4503A could be involved in these multiple step reactions.

[Long-term effect of voice rehabilitation in 125 patients following total laryngectomy]

One hundred and twenty-five patients received voice rehabilitation operations following total laryngectomy over the period from August 1977 to December 1994. Among them, 119 were male and 6 were female, the eldest was 70 years old and the youngest 30 years old, and the average age was 55.3 years. Clinical staging was as follows: stage II, 2 cases; stage III, 45 cases; stage IV, 66 cases; and recurrence, 12 cases. The voice rehabilitation operations included pharynx-trachea anastomosis 18 cases and trachea-esophagus fistulization 107 cases. One hundred and fourteen patients were followed-up for 13 months to 18 years. The 3, 5, and 10 year survival rates were 78.2%, 61.4%, and 40.5% respectively. The effective rates of voice rehabilitation according to hearing voice distance were 84.6%, 81.1%, and 67.5% 3 weeks, 1 year, and 5 years respectively after operation. The causes of failure were closure of fistula 15 cases; food aspiration 8 cases and unknown 3 cases. The clinical value, advantages and disadvantages of voice rehabilitation, and the time to evaluate the effect of voice rehabilitation were discussed.

Improved stability and electrophoretic properties of preformed fluorescent cationic dye-DNA complexes in a taps-tetrapentylammonium buffer in agarose slab gels

High-resolution capillary electrophoresis sizing of preformed complexes of bis-intercalating fluorescent dyes with double-stranded DNA has been demonstrated using hydroxyethylcellulose and 3-[tris-(hydroxymethyl) methylamino]-1-propanesulfonic acid-tetrapentylammonium (Taps-NPe+4) buffers (S. M. Clark and R. A. Mathies, Anal. Chem. 69, 1355-1363, 1997). Such capillary electrophoresis separations were unattainable in conventional buffers containing other cations such as Tris+, Na+, and NH+4. We report here the behavior of preformed double-stranded DNA-dye complexes on agarose slab gel electrophoresis in 40 mM Taps-NPe+4, 1 mM H2EDTA, pH 8.2. Upon electrophoresis in this buffer (a) complexes formed at DNA base pairs:dye ratios ranging from 100:1 to 5:1 show the same mobility; (b) the half-lives of DNA-dye complexes with monointercalators are two- to threefold longer than those in commonly used Tris buffers; (c) there is little dye transfer between labeled and unlabeled DNA molecules; and (d) precise two-color sizing of preformed restriction fragment-dye complexes with fluorescent bisintercalators is achieved.

Glucocorticoid repression of gonadotropin-releasing hormone gene expression and secretion in morphologically distinct subpopulations of GT1-7 cells

Two morphologically distinct subpopulations of GT1-7 cells have been characterized and examined for their responsiveness to glucocorticoids. Type I cells have a neuronal phenotype, extending many lengthy processes, and express neuronal, but not glial, markers. Type II cells show weaker or negative immunostaining for neuronal markers and exhibit fewer processes. The effect of glucocorticoids on gonadotropin-releasing hormone (GnRH) secretion and gene expression was compared in type I and type II GT1-7 cells. For secretion studies, cells were attached to Cytodex beads and perifused with control medium or medium containing dexamethasone (dex). The high level of GnRH secreted by type I cells was slightly enhanced in the presence of dex, whereas dex rapidly and profoundly decreased the already low level of GnRH secreted by type II cells. Immunocytochemistry for GnRH showed dark reaction product in the cell bodies and processes of type I cells and little or no immunoreactivity in type II cells. Both the endogenous mouse GnRH mRNA and the transcriptional activity of a mouse GnRH promoter luciferase reporter gene plasmid were suppressed to a greater extent in type II cells than in type I. In electrophoretic mobility shift assays, there was no difference between type I and type II nuclear extracts in the pattern of protein-DNA complexes formed on two previously identified negative glucocorticoid response elements located at -237 to -201 and -184 to -150 bp of the mouse promoter. Both cell types contained glucocorticoid receptors (GR) by Western blot analysis. Cytosols from type I or type II cells were incubated with [3H]dex to obtain GR binding parameters. Binding data were consistent with a one-site model for dex binding in each case. Small differences in Kd (1.7 nM, type I; 3.1 nM, type II) or Bmax (approximately 3600 sites/cell, type I; approximately 1800 sites/cell, type II) were not likely to account for the differential sensitivity to dex treatment. In conclusion, nuclear alterations in type II cells leading to greater transcriptional susceptibility to dex, coupled with low GnRH storage levels, may be reflected in exquisite sensitivity of GnRH secretion to glucocorticoid repression. This represents the first example of a steroid hormone acting directly on GnRH-producing cells to alter GnRH secretion.

Crystal structure of mouse CD1: An MHC-like fold with a large hydrophobic binding groove

CD1 represents a third lineage of antigen-presenting molecules that are distantly related to major histocompatibility complex (MHC) molecules in the immune system. The crystal structure of mouse CD1d1, corresponding to human CD1d, at 2.8 resolution shows that CD1 adopts an MHC fold that is more closely related to that of MHC class I than to that of MHC class II. The binding groove, although significantly narrower, is substantially larger because of increased depth and it has only two major pockets that are almost completely hydrophobic. The extreme hydrophobicity and shape of the binding site are consistent with observations that human CD1b and CD1c can present mycobacterial cell wall antigens, such as mycolic acid and lipoarabinomannans. However, mouse CD1d1 can present very hydrophobic peptides, but must do so in a very different way from MHC class Ia and class II molecules.

Cloning, mapping, and tissue distribution of a human homologue of the mouse jerky gene product

Inactivation of the jerky gene by insertion of a transgene into the mouse genome results in epileptic seizures in transgenic mice. This finding indicates that the jerky gene plays an important role in inducing epilepsy syndromes in mice. We report here our efforts in cloning, chromosomal mapping, and analysis of tissue distribution of a novel human gene, the HHMJG, a homologue to the mouse jerky gene product. We have successfully identified a full length cDNA clone encoding a novel human protein homologous to the mouse jerky gene product. The finding was based on the result of an analysis of EST (expressed sequence tag) sequences of a clone from a human tonsil cDNA library. A 4.0 kb mRNA species of the HHMJG is abundantly expressed in the majority of human tissues examined, including brain and skeletal muscle. However, in the testes, two mRNA species of the HHMJG, approximately 2.0 and 4.0 kb, are abundantly expressed. Sequence analysis of the HHMJG cDNA indicates that it encodes a putative protein of 51 kD, which shares significant sequence homology to not only the mouse jerky gene product but also some nuclear regulatory proteins, such as centromere binding protein-B. The predicted nuclear localization of the HHMJG product suggests that this protein may function as a nuclear regulatory protein. The result of human chromosomal mapping shows that the HHMJG is located on human chromosome 11q21. Our identification of the HHMJG cDNA provides a potential gene candidate to further investigate the biological significance and clinical implications of the HHMJG in human epilepsy.

A novel endothelin receptor type-B-like gene enriched in the brain

We report here our effort of cloning and characterization of a novel human gene, which encodes a putative human endothelin receptor type B like protein (hET(B)R-LP), from a human hippocampus tissue cDNA library. hET(B)R-LP consists of 614 amino acids with seven putative transmembrane domains. The deduced amino acid sequence of hET(B)R-LP is 52% similar and 26.7% identical to human endothelin type B receptor. A 4.0 kb mRNA of hET(B)R-LP is abundantly expressed in the human brain. The results of in situ hybridization and reverse transcriptase in situ gene amplification reveal tissue distribution and cellular localization of signals of hET(B)R-LP mRNA in the neuronal cells, particularly concentrated in Purkinje cells of the cerebellum, and neuronal cells of the hippocampus of human brain, including pyramidal cells of Ammon's horn and granule cells of the dentate gyrus. A 4.0 kb mRNA of hET(B)R-LP is also less abundantly expressed in the liver and the placenta. Expression of recombinant protein, hET(B)R-LP/HA, in cells of COS7 and HEK293 transfected with plasmid DNA, hET(B)R-LP/HA/pcDNA1/Amp, was confirmed by Northern blot analysis and by immunofluorescence staining of cells with anti-HA antibody. Specific binding of radiolabeled ET-1 and ET-3 to membrane preparations and to intact cells expressing recombinant protein of hET(B)R-LP/HA did not show any significant difference of binding properties between cells transfected with plasmid DNA, hET(B)R-LP/HA/pcDNA1/Amp, and cells untransfected, including both COS7 cells and HEK293 cells. The results of assays of measuring Ca++ mobilization and cAMP production in HEK293 cells indicate that ET-1, ET-3, bombesin and neuropeptide Y are unable to produce any kind of significant difference of Ca++ mobilization and cAMP production between HEK293 cells expressing recombinant protein and HEK293 cells untransfected or HEK293 cells transfected with vector DNA only (pcDNA1/Amp) in functional assays performed. Therefore, its ligand and physiological significance of hET(B)R-LP remains to be discovered.

Cloning and characterization of a novel human DNase

The therapeutic significance of recombinant human DNase I in treating the patients with cystic fibrosis has risen our interests in identifying other human DNase I-like enzymes to study their biological significance. Here we described our work of cloning and characterization of a novel gene, which encodes a human protein homologous to human DNase I. A full length cDNA clone of this gene consists of 1290 bp, encoding a polypeptide of 306 amino acids. The deduced amino acid sequence of this novel human DNase (nhDNase) is 45% identical to that of human DNase I. Among sixteen human tissues examined by Northern Blot, high level expression of nhDNase was found in human liver and spleen. Recombinant protein of nhDNase was produced in a Baculovirus expression system and purified by chromatography and reverse-phase HPLC. Purified recombinant nhDNase migrated as a single band of about 33 kD molecular weight analyzed by SDS-PAGE. The DNase activity of nhDNase was demonstrated by assay of hydrolysis of S.S.DNA. Its activity was dependent upon the presence of divalent metal irons, calcium and magnesium. However, unlike bovine pancreas DNase I, nhDNase was not inhibited by G-actin of bovine muscle, which indicates the physiological significance of this enzyme in clinical implication.

[A simplified method for detection of genomic subtyps of HBV S-gene]

When the 513 bp amplified fragments of HBV S-gene, known subtypes, were digested with Msp I and BamH I, the following phenomena appeared: adr subtypic 513 bp was fragmentized to 320 bp and 193 bp by Msp I; ayw subtype was digested and fragmentized to 295 bp and 218 bp by BamH I; ayw could also be fragmentized to become 326 bp and 187 bp digested by Msp I. Howerev, adw subtype was not digested by Msp I and BamH I nor adr by BamH I. The experimental patterns in agarose gel electrophoresis were tallied with the expected patterns. Each HBV subtypes gave unique size of digestive fragments which was easy to observe and distinguish on agarose gel. This study provided a new classification scheme for HBV-DNA and could be used for epidemiological investigation of HBV infection.

[Immunohistochemical study of endothelin-1 in adrenal tumors]

10 cases of aldosteronoma, 10 cases of pheochromocytoma and 10 cases of adrenocortical adenoma and hyperplasia were studied by using immunohistochemical staining for ET-1. All of the tumors were stained positivily for ET-1, ranging from weak diffuse (+) staining to moderate staining (++). In aldosteronomas ET-1 receptro may be down-regulated and ET-1 may play a paracrine role in regulating catecholamine in pheochromocytoma.

Molecular cloning and characterization of the human anaphylatoxin C3a receptor

In a human neutrophil cDNA library, an orphan G-protein-coupled receptor, HNFAG09, with 37% nucleotide identity to the C5a receptor (C5a-R, CD88) was identified. A novel feature of this gene, unlike C5a-R and other G-protein-coupled receptors, is the presence of an extraordinarily large predicted extracellular loop comprised of in excess of 160 amino acid residues between transmembrane domains 4 and 5. Northern blot analysis revealed that expression of mRNA for this receptor in human tissues, while similar, was distinct from C5a-R expression. Although there were differences in expression, transcripts for both receptors were detected in tissues throughout the body and the central nervous system. Mammalian cells stably expressing HNFAG09 specifically bound 125I-C3a and responded to a C3a carboxyl-terminal analogue synthetic peptide and to human C3a but not to rC5a with a robust calcium mobilization response. HNFAG09 encodes the human anaphylatoxin C3a receptor.

Crystal structure determination of an acidic neurotoxin (BmK M8) from scorpion Buthus martensii Karsch at 0.25 nm resolution

The crystal structure of an acidic neurotoxin, BmK M8, from Chinese scorpion Buthus martensii Karsch was determined at 0.25 nm resolution. The X-ray diffraction data of BmK M8 crystals at 0.25 nm resolution were collected on a Siemens area detector. Using molecular replacement method with a basic scorpion toxin AaH II in a search model, the cross-rotation function, PC-refinement and translation function were calculated by X-PLOR program package. The correct orientation and position of BmK M8 molecule in crystal were determined in a resolution range of 1.5-0.35 nm. The crystallographic refinement was further performed by stereo-chemical restrict least-square technique, followed by simulated annealing, slow-cooling protocols. The final crystallographic R-factor at 0.8-0.25 nm is 0.171. The standard deviations of bond length and bond angle from ideality are 0.0017 nm and 2.24 degrees, respectively. The final model of BmK M8 structure is composed of a dense core of secondary structure elements by a stretch of alpha-helix with two and a half turns (residues 19-28) and a three-stranded antiparallel beta-sheet (residues 2-4, 32-37, 45-51). In addition, three loops protruded from the structural core. The general folding properties of BmK M8 molecule were described; a common structure motif which may appear in all scorpion neurotoxins was identified. The conserved aromatic residues and charged residues were found to be distributed on two roughly opposite surfaces of the molecule. The relationship between these two faces and receptor-binding sites are also discussed.

A mechanism for inducing plant development: the genesis of a specific inhibitor

Parasitic strategies are widely distributed in the plant kingdom and frequently involve coupling parasite organogenesis with cues from the host. In Striga asiatica, for example, the cues that initiate the development of the host attachment organ, the haustorium, originate in the host and trigger the transition from vegetative to parasitic mode in the root meristem. This system therefore offers a unique opportunity to study the signals and mechanisms that control plant cell morphogenesis. Here we establish that the biological activity of structural analogs of the natural inducer displays a marked dependence on redox potential and suggest the existence of a semiquinone intermediate. Building on chemistry that exploits the energetics of such an intermediate, cyclopropyl-p-benzoquinone (CPBQ) is shown to be a specific inhibitor of haustorial development. These data are consistent with a model where haustorial development is initiated by the completion of a redox circuit.

[Endothelin-1 receptors of the normal adrenal gland and adrenal tumors in human]

Endothelin-1 (ET-1) receptors of normal adrenal gland (ADR, 6 cases), aldosterone-producing adenoma (APA, 5 cases), idiopathic hyperaldosteronism (IHA, 4 cases) and pheochromocytoma (PHE, 6 cases) in human were measured by radioligand binding assay (RBA) of receptors. Binding studies using 125I-ET-1 as a radio ligand showed the presence of a single class of high-affinity binding sites for ET-1 in all of the above tissues. The values of dissociation constant (Kd) of ET-1 for its receptor were similar in ADR, APA and IHA (28.3 +/- 2.5, 27.9 +/- 6.1, 27.7 +/- 1.9 pmol/L, respectively), but the maximal binding capacity (Bmax) of ET receptor tended to be lower in APA tissue (107.2 +/- 13.2 fmol/mg protein) in comparison with ADR (P < 0.01) and IHA (P < 0.05, 274.9 +/- 40.8, 247.0 +/- 19.8 fmol/mg protein, respectively). Both the Kd (50.8 +/- 5.1 pmol/L) and Bmax (675.3 +/- 93.7 fmol/mg protein) in PHE were higher than those in ADR (P < 0.01), APA (P < 0.01) or IHA (P < 0.05 for Kd, P < 0.01 for Bmax). Our data may suggest that there is the down-regulation for ET-1 receptor in APA and support the concept of an important role of ET-1 in the paracrine-autocrine regulation of aldosterone and catecholamine secretion in the adrenal and adrenal tumors.

Changes of plasma endothelin concentrations before and after percutaneous balloon mitral valvuloplasty in patients with mitral stenosis

Plasma concentrations of endothelin in blood from the femoral vein and the antecubital vein were measured in 35 patients with mitral stenosis and heart failure before and after percutaneous balloon mitral valvuloplasty (PBMV). The basal plasma concentrations of endothelin in blood from the antecubital vein in the patients were significantly higher than those in 32 control subjects (15.40 +/- 3.32 vs. 9.59 +/- 2.66 pg/ml, P < 0.001). Plasma endothelin concentrations in patients in New York Heart Association functional classes II and III were significantly higher than those in control subjects, respectively. The concentrations of endothelin in patients with atrial fibrillation were also significantly higher than those in patients with normal sinus rhythm. Ten to fifteen minutes after PBMV, plasma endothelin concentrations in blood from the femoral vein significantly decreased from 16.14 +/- 3.34 to 13.74 +/- 3.78 pg/ml (P < 0.01). Seventy-two hours after the procedure, the concentrations of endothelin in blood from the antecubital vein had fallen to 12.31 +/- 2.55 pg/ml (P < 0.001 vs. before PBMV and control subjects). Plasma endothelin concentrations still tended to be higher in patients with atrial fibrillation than those in normal sinus rhythm, but the difference did not reach statistical significance. There were weak but significantly correlations of plasma endothelin concentrations with the mean left atrial pressure (r = 0.424, P < 0.001), mean right atrial pressure (r = 0.323, P < 0.01), mean transmitral pressure gradient (r = 0.397, P < 0.001), heart rate (r = 0.350, P < 0.005) and mitral valve area (r = -0.454, P < 0.001) in the patients before and after PBMV.

[A morphometric study on hippocampus of epileptic rats induced by coriaria lactone]

This experiment was carried out with these rats were injected with 3.8 microliters (19 micrograms) convulsive dosage of coriaria lactone (CL) in the left cerebral motor cortex of the forelimb to induce acute focal epilepsy, while the other 5 rats as controls (no seizure) received normal saline solution of the same volume and at the same location. The brains were taken after seizuring for 60 min. The volume (water displacement method) and weight of the brain were measured. The brain was cut coronally and the structures of hippocampus were compared morphologically with those of the pair-matched control. The area of hippocampal formation was measured with paraffin section by test grid under 40x. The mean size (Feret's diameter) of pyramidal neurons in CA1 region was measured with semithin section by ocular micrometer under 1000x. The areal fraction of several organelles of the CA1 pyramidal cells was measured with EM negative film by magnifier. Under conditions of the consistent reference space, especially the size of CA1 pyramidal cells, the areal fraction of rough endoplasmic reticulum, lysosome and mitochondria increased significantly (P < 0.05) in epileptic rats. It indicated that their volume increased. The results show that certain ultrastructural changes have taken place after seizuring for 60 min.

[Effects of L-arginine on acute hypoxic pulmonary hypertension and production of endothelin-1 in vivo and in cultured endothelial cells]

This study is aimed to investigate the effects of L-arginine, a precursor of the formation of nitric oxide, on acute hypoxic pulmonary hypertension in vivo and on production of endothelin-1 both in vivo and in cultured endothelial cells. In mechanically ventilated anesthetized dogs (n = 7), L-arginine (0.5 g/kg) reduced the mean pulmonary arterial pressure and femoral arterial pressure during hypoxic ventilation and its action lasted for about 30 minutes. Meanwhile, plasma endothelin-1 in the pulmonary and femoral artery had no remarkable change. In cultured endothelial cells from umbilical veins, different concentrations of L-arginine had no influence on endothelin-1 level of culture medium in 4 or 24 hours after the addition of L-arginine. These results indicate that L arginine can decrease the pulmonary arterial pressure during acute hypoxia, which may be associated with the increase of nitric oxide production.

A cDNA encoding the calcitonin gene-related peptide type 1 receptor

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse biological effects including potent vasodilator activity. We report here the cloning of a complementary DNA (cDNA) encoding a human CGRP1 receptor, which shares significant peptide sequence homology with the human calcitonin receptor, a member of the G-protein-coupled receptor superfamily. Northern blot analysis revealed that the messenger RNA for this receptor is predominantly expressed in the lung and heart. In situ studies showed specific localization of the receptor mRNA to alveolar cells in the lung and to cardiac myocytes in the heart. Stable expression of the cDNA in human embryonic kidney 293 (HEK 293) cells produced specific, high affinity binding sites for CGRP that displayed pharmacological and functional properties very similar to native human CGRP1 receptor. Exposure of these cells to CGRP resulted in a 60-fold increase in cAMP production, which was inhibited in a competitive manner by the CGRP1 receptor antagonist, CGRP-(8-37).

Fate of 4"-epiacetylamino-4"-deoxyavermectin B1 in rats

Distribution, excretion, and metabolism of 4"-epiacetylamino-4"-deoxyavermectin B1 (AAB1), a new avermectin, were determined in Sprague-Dawley VAF rats. The rats were dosed orally for 7 consecutive days at approximately 6 mg/kg body weight with [5-3H]AAB1 as a 1.2 mg/ml aqueous suspension containing 0.5% methyl cellulose. Rats were killed at approximately 7 hours and 1, 2, and 5 days after the last dose. The major route of excretion of drug residues was via feces, with less than 1% of the dose found in urine. The radioactive residue levels in tissues and blood followed the order GI > liver approximately equal to fat approximately equal to kidney > muscle > plasma approximately equal to red blood cells and were comparable in male and female rats. HPLC-radiochromatographic profiles revealed that 4"-epiamino-4"-deoxyavermectin B1a was the major metabolite in all tissue samples and plasma samples, and was usually the major residue at later time points. The results indicate that N-deacetylation of AAB1 was the primary route of metabolism in rats. A distinct feature of the metabolism was a sex difference in the extent of metabolism. When metabolite profiles of male and female rats killed at the same time were compared, less parent drug and more of the N-deacetylated metabolite were found in the female rats, indicating that the drug was metabolized more extensively in female rats than in male rats. The sex difference in the extent of metabolism was also demonstrated in vitro.

Analysis and Modeling of Time-Dose-Mortality of Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria (Orthoptera: Acrididae) from Beauveria, Metarhizium, and Paecilomyces Isolates from Madagascar

A complementary log-log (CLL) model was used to model time-dose-mortality relationships from bioassay tests of 26 fungal isolates mostly from Madagascar, Africa, against three acridid species, all referred to here as "grasshoppers." The fungal pathogens included 15 isolates of Beauveria bassiana, 9 isolates of Metarhizium flavoviridae, and 2 isolates of Paecilomyces spp. Grasshopper species tested included Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria. The scaled deviance, mean deviance, Pearson X2 statistic, Hosmer-Lemeshow (H-L) C statistic, and three-dimensional time-dose-mortality graphs were used to assess extra-binomial variation, data points that were potential outliers, conformance of the scaled deviance statistic and Pearson's X2 statistic to a chi2 distribution, and the fit of the CLL model. The H-L C statistic also was found to be useful in showing the goodness of fit of the CLL model for the fungal isolates prior to modeling the extra-binomial variation. After the extra-binomial variation was modeled using Williams' method, the slope from maximum likelihood estimation, modified log(LD50) estimates (which were corrected for background mortality using the CLL model), a dynamic ranking of the log(LD50) values over time, and a three-dimensional plot of time, dose, and mortality of the three grasshopper species were used to evaluate the effectiveness of the fungal isolates. In general, the CLL model provided a rather poor fit of the fungal isolates which had a large number of replicate trials in the bioassay tests (i.e., a large sample size) due to extra-binomial variation. The CLL model provided an excellent fit of the time-dose-mortality relationships of such isolates after the extra-binomial variation was modeled and included in the CLL model. Metarhizium isolates MFV and SP5 were found to be the most virulent isolates tested against M. sanguinipes, followed by Metarhizium isolates: SP8, SP7, SP9, SP6, and SP1, and Beauveria isolate S33B. Metarhizium isolates SP3, SP5, SP6, and SP9, and Beauveria isolates SP11, SP12, SP13, and SP16 showed higher levels of virulence against L. migratoria migratorioides over more of the time periods tested than the other pathogen isolates examined. Metarhizium isolates SP9 and SP5 were the most effective isolates tested against S. gregaria. In general, the Metarhizium isolates were more virulent against the grasshoppers than the Beauveria isolates, which were more virulent than the Paecilomyces isolates. The CLL model was found to be very useful in describing grasshopper mortality as a function of time and dose. This approach combined with model and fungal isolate assessment statistics will be helpful for determining which pathogen isolates have the greatest potential for controlling grasshoppers and other pests in the future.