An SNP in the MyoD1 gene intron 2 associated with growth and carcass traits in three duck populations

Myogenic differentiation 1 (MyoD1) genes belong to the MyoD gene family and play key roles in growth and muscle development. This study was designed to investigate the effects of variants in the MyoD1 gene on duck growth and carcass traits. Three duck populations (Cherry Valley, Jingjiang, and Muscovy) were sampled, their growth and carcass traits were measured, and they were genotyped using the PCR-RFLP method. The results showed one novel polymorphism, an alteration in intron 2 of the MyoD1 gene (A to T). It was associated with the traits of weight at 8 weeks, carcass weight, breast muscle weight, leg muscle weight, eviscerated percentage, percentage of leg muscle weight, dressing percentage, and lean meat percentage. This alteration in intron 2 of MyoD1 may be linked with potential major loci or genes affecting some growth and carcass traits.

Cryosurgery for treatment of subcutaneously xenotransplanted tumors in rats and its effect on cellular immunity

Cryosurgery has shown encouraging therapeutic effects on some solid tumors but its effect on the cellular immunity remains unclear. We developed a subcutaneously xenotransplanted tumor model in SD rats to directly evaluate the immune response by detecting the serum cytokine levels, T-cell responses to tumor derived antigens, and the cytolytic activity of peripheral blood mononuclear cells against the W256 cancer line with apoptosis of cells being detected using TUNEL method. 66 SD rats were divided into 2 groups with group A having 36 rats and group B having 30 rats. 30 rats in group B were equally divided into 3 groups, tumor group B, cryosurgery group B and surgery group B, with 10 rats each. 36 rats in group A were equally divided into 2 groups, cryosurgery group A and tumor group A and treatment was done accordingly. The results showed that cryosurgery induced not only destruction of the tumor cells but also cell apoptosis around the cryosurgery foci. The apoptosis ratio reached the peak 12 h after cryosurgery, with an apoptosis rate of (68.28 ± 7.85)% .Compared with surgical resection that caused significant reduction in CD31 and CD41 cell percentages, cryosurgery resulted in significantly increased percentages of CD31 and CD41 cells (P < 0.05) with a relative increase of the CD41/CD81 cell ratio. However, sIL-2R level of peripheral blood of rats in cryosurgery group which decreased more rapidly than that in surgery group over time was significantly different 3 and 5 weeks after treatment compared to surgery group (P < 0.01). Moreover, cytotoxicity of mononuclear cell was significantly enhanced after cryosurgery, which is significantly higher in cryosurgery group (P = 0.05). These results demonstrate that in addition to tumor cell destruction, cryosurgery also results in enhanced cellular immunity and antitumor immune response of the rats with subcutaneously xenotransplanted tumor, suggesting the great potential of argon-helium cryosurgery in clinical management.

The roles of Dippu-allatostatin in the modulation of hormone release in Locusta migratoria

Dippu-allatostatins (ASTs) have pleiotropic effects in Locusta migratoria. Dippu-ASTs act as releasing factors for adipokinetic hormone I (AKH I) from the corpus cardiacum (CC) and also alter juvenile hormone (JH) biosynthesis and release from the corpus allatum (CA). Dippu-AST-like immunoreactivity is found within lateral neurosecretory cells (LNCs) of the brain and axons within the paired nervi corporis cardiaci II (NCC II) to the CC and the CA, where there are extensive processes and nerve endings over both of these neuroendocrine organs. There was co-localization of Dippu-AST-like and proctolin-like immunoreactivity within these regions. Dippu-ASTs increase the release of AKH I in a dose-dependent manner, with thresholds below 10(-11)M (Dippu-AST 7) and between 10(-13) and 10(-12)M (Dippu-AST 2). Both proctolin and Dippu-AST 2 caused an increase in the cAMP content of the glandular lobe of the CC. Dippu-AST 2 also altered the release of JH from the locust CA, but this effect depended on the concentration of peptide and the basal release rates of the CA. These physiological effects for Dippu-ASTs in Locusta have not been shown previously.

A putative farnesoic acid O-methyltransferase (FAMeT) orthologue in Drosophila melanogaster (CG10527): relationship to juvenile hormone biosynthesis?

Juvenile hormones (JHs) are key regulators of both metamorphosis and adult reproductive processes. Farnesoic acid O-methyltransferase (FAMeT) is thought to be an important enzyme in the JH biosynthetic pathway, catalyzing methylation of farnesoic acid (FA) to methyl farnesoate (MF). Previous evidence in other insects suggested that FAMeT is rate limiting and regulated by a neuropeptide family, the allatostatins. A full-length cDNA encoding a 296 amino acid putative FAMeT has been isolated. A recombinant (r)FAMeT was cloned, expressed and a specific antiserum generated. rFAMeT was assayed for enzymatic activity using a radiochemical assay. In this assay, no activity was detected either with rFAMeT alone or when added to a corpus allatum CA extract. Immunohistochemical analysis was used to confirm the presence of FAMeT in the CA of Drosophila melanogaster ring gland. Analysis of MF, JHIII and JHB3 release in wild type and mutant stocks in the presence and absence of Drome AST (PISCF-type) suggest that Drosophila FAMeT has little if any effect on sesquiterpenoid biosynthesis. Drome AST appears to have a select effect on JH bisepoxide biosynthesis and not MF or JHIII. Additional analysis of MF, JHIII and JHB3 release in strains with a deficiency or decrease of FAMeT compared to wild type shows no significant decrease in MF, JHIII or JH bisepoxide synthesis. Deficiency strains that reduce the level of FAMeT showed reduced longevity relative to wildtype but this result may be due to other genetic influences.

ATP7B antisense oligodeoxynucleotides increase the cisplatin sensitivity of human ovarian cancer cell line SKOV3ipl

The objective of this study was to investigate the effect of ATP7B antisense oligodeoxynucleotides (ASODNs) on regulating the sensitivity to cisplatin in ovarian carcinoma cell line SKOV3ip1. The ATP7B ASODNs and the corresponding sense oligodeoxynucleotide (SODN) as control were transfected into SKOV3ip1 cells by lipofectamine-2000. The changes of ATP7B were detected by reverse transcription-polymerase chain reaction, flow cytometry, and Western blotting. The survival rate of the SKOV3ip1 cells was assessed by MTT assay. Compared with nontransfected cell, the transfer of ASODN/lipofectin (LF) into SKOV3ip1 cells resulted in (1) 73.70% and 48.30% reduction of ATP7B in messenger RNA and protein, respectively, (2) an obviously decreased intracellular fluorescence intensity from 79.42 to 50.87 (P < 0.01), and (3) a decreased IC(50) value for cisplatin from 126.63 to 80.90 micromol/L (P < 0.01), while no significant changes were detected for groups treated with SODN/LF and LF only. ASODN transfection can inhibit the expression of ATP7B and increase the cisplatin sensitivity in SKOV3ip1 cells.

Laparoscopically assisted sigmoid colon vaginoplasty in women with Mayer-Rokitansky-Kuster-Hauser syndrome: feasibility and short-term results

OBJECTIVES

To evaluate the technical feasibility and anatomical and functional outcomes of laparoscopically assisted sigmoid colon vaginoplasty (LASV) in women with Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome.

DESIGN

A retrospective review of prospectively collected data.

SETTING

Shanghai First People's Hospital, Shanghai Jiao Tong University.

POPULATION

Twenty-six women with MRKH syndrome.

METHODS

A record was made of mean operating time, length of hospital stay, perioperative complications and the anatomical and functional outcomes of surgery.

MAIN OUTCOME MEASURES

The perioperative results, complications and anatomical and functional outcomes of LASV (with median 20 months follow up, range 5-48 months).

RESULTS

The mean operating time and hospital stay were 238 minutes and 9.8 days, respectively. The mean fall in haemoglobin was 2.0 g/dl. The only significant perioperative complications were one case with blood transfusion and three cases with infection (one with urinary tract and two with adjunctive incision). A functioning vagina 10 to 15 cm in length and 4 cm in width was created in all women. Introital stenosis occurred in only two women (2 months later). Twenty-two women subsequently had intercourse and 20 women (91%) were satisfied with the surgery and subsequent sexual activity.

CONCLUSIONS

LASV is an effective approach for women with MRKH syndrome. Both the anatomical and functional outcomes are satisfactory.

[Detection of sexual hormone in semen of patients with idiopathic azoospermia or oligospermia and its significance]

OBJECTIVES

To detect the sexual hormone level in semen of patients with idiopathic azoospermia and oligospermia, and further analyze the relationship between sexual hormone and idiopathic azoospermia and oligospermia.

METHODS

50 male patients with idiopathic azoospermia, 50 in idiopathic oligospermia and 50 male controls with normal sperm density were selected. The sperm density and sexual hormone in semen were detected respectively by routine semen analysis and chemical luminescence technique.

RESULTS

The values of LH were (5.19 +/- 0.67) IU/L and (4.77 +/- 0.68) IU/L, and those of FSH were (1.90 +/- 0.79) IU/L and (2.27 +/- 0.25) IU/L in idiopathic azoospermia and oligospermia respectively, and the values of LH and FSH were (2.19 +/- 0.22) IU/L and (1.61 +/- 0.14) IU/L in normal control group respectively. There were significant differences in the values of LH and FSH between idiopathic azoospermia and normal control group(P < 0.01 or P < 0.05). The values of PRL were (6.25 +/- 0.51) ng/ml and (6.33 +/- 0.34) ng/ml, and those of T were (1.51 +/- 0.12) ng/ml and (1.68 +/- 0.71) ng/ml in idiopathic azoospermia and oligospermia respectively, and the values of PRL and T were (6.36 +/- 0.32) ng/ml and (1.83 +/- 0.09) ng/ml in normal control group respectively. There were no significant difference in the values of PRL between idiopathic azoospermia, oligospermia and normal control group, but there were significant differences of T between idiopathic azoospermia and normal control. Compared with 0.84 +/- 0.20 in normal control, the values of T/LH were 0.35 +/- 0.09 and 0.29 +/- 0.04 in idiopathic oligospermia and azoospermia respectively and there were significant differences(P < 0.05).

CONCLUSIONS

The changes of LH, FSH and T values may be one of the reasons that cause the dysfunction of spermatogenesis and sperm maturation in patients with idiopathic azoospermia and oligospermia. The study of semen hormone may lead to new strategies in the treatment to azoospermia and oligospermia.

In vitro induction of tetraploid plants from diploid Zizyphus jujuba Mill. cv. Zhanhua

Tetraploid plants of Zizyphus jujuba Mill. cv. Zhanhua were obtained with in vitro colchicine treatment. Shoot tips from in vitro-grown plants were treated with five different concentrations of colchicine (0.01, 0.03, 0.05, 0.1, 0.3%) in liquid MS medium (Murashige and Skoog 1962), and shaken (100 rpm) at 25 degrees C in darkness for 24, 48, 72 or 96 h, respectively. Tetraploids were obtained at a frequency of over 3% by using 0.05% colchicine (48 h, 72 h) and 0.1% colchicine (24 h, 48 h) treatment as determined by flow cytometry. Cytological and morphological evidence confirmed the results of flow cytometric analysis. The chromosome number of diploid plants was 24 and that of tetraploid plants was 48. The stomata sizes of tetraploid plants were significantly larger than those of diploid plants, while the frequency of stomata were reduced significantly. Similarly, the chloroplast number of guard cells of tetraploid plants increased significantly. The selected tetraploid plants were grafted onto mature trees of Z. jujuba Mill. cv. Zhanhua in the field, resulted in thicker stems, rounder and succulent leaves, larger flowers and a delay in florescence time (3-4 days later) than diploid plants.

Preparation of new amino acid complex nanoparticles of bismuth and leucine

The new amino acid complex nanoparticles of bismuth and leucine can be prepared very easily by a room temperature solid-solid reaction. The various characterizations indicate that the formula of the complex is BiCl[(CH(3))(2)CHCH(2)CHNH(2)COO](2)1.5H(2)O. The crystal structure of the solid complex belongs to monoclinic system with the lattice parameters: a = 1.6036 nm, b = 1.9903 nm, c = 2.1979 nm and beta=108.06 degrees . The new solid complex is nanoparticles with average size about 80 nm.

An efficient adventitious shoot regeneration system for Zhanhua winter jujube (Zizyphus jujuba Mill.) using leaf explants

The direct induction of adventitious shoots from leaf explants obtained from adult plants of Zhanhua winter jujube, an elite variety of Zizyphus jujuba Mill., is reported. The percentage of leaf explants producing shoots and the average number of shoots per explant were significantly improved when 10-day-old leaves were explanted onto Woody Plant Medium and maintained initially in the dark. The plant growth regulator thidiazuron (TDZ) was effective in stimulating shoot regeneration from leaf explants of Zhanhua winter jujube. The highest efficiency of shoot formation was observed with a 20-day culture in the dark on WPM containing 4.54 microM TDZ and 2.85 microM indoleacetic acid (IAA). The regenerated shoots were transferred to MS medium containing 0.89 microM benzyladenine and 5.77 microM gibberellic acid for growth. When the shoots were about 2 cm in height, they were transferred to Nitsch medium supplemented with 1.14 microM IAA and 2.46 microM indolebutyric acid to induce rooting. This system of adventitious shoot production from leaf explants of adult plants could be useful for the genetic engineering and polyploidization of winter jujube.

A study of signal transduction for the two diuretic peptides of Diploptera punctata

We investigated second messengers involved in the action of the CRF-related peptide Dippu-DH46 and the calcitonin-like peptide Dippu-DH31 in Diploptera punctata. Dippu-DH46 causes a dose-dependent increase in intracellular cAMP levels, its diuretic activity is mimicked by cAMP agonists, but is attenuated by Rp-cAMPS. Dippu-DH46 acts synergistically with kinins and thapsigargin; both mobilize intracellular Ca2+. Dippu-DH46 also acts synergistically with cAMP agonists, and its effect is inhibited by a PKC inhibitor, suggesting it also activates intracellular Ca2+. Dippu-DH31 has no effect on cAMP levels and its activity is not blocked by cAMP agonists. Neither peptide stimulated cGMP levels in a dose-dependent manner, nor does cGMP have any effect on fluid secretion.

A chitosan-arginine conjugate as a novel anticoagulation biomaterial

Chitosan (CS) was modified with arginine using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. FTIR and 13C NMR spectra showed that arginine was chemically coupled to CS to form a chitosan-arginine conjugate (CS-ArgC). The substitution degree of arginine in CS estimated from elemental analysis was 20.1%. The circular dichroism spectra indicated that the incorporation of arginine significantly altered the conformation of thrombin; while no obvious variation in the conformation of thrombin was observed with the addition of CS. The anticoagulation activity of glucose aldehyde crosslinked CS-ArgC and CS membranes was evaluated by assaying prothrombin time (PT), thrombin time (TT) and activated partial thromboplastin time (APTT). The APTT of CS-ArgC membrane was prolonged two times as that of CS counterpart, suggesting that the CS-ArgC is a promising candidate as an anticoagulation biomaterial.

Localization and physiological effects of RFamides in the corpora allata of the cockroach Diploptera punctata in relation to allatostatins

The distribution of FMRFamide immunoreactivity in the brain-retrocerebral complex of adult female Diploptera punctata was examined. Immunoreactivity was observed in the brain and corpus allatum as well as in the corpus cardiacum. Immunoreactivity co-localized with allatostatin immunoreactivity within several lateral neurosecretory cells of the brain and in their endings within the corpus allatum. By in vitro radiochemical assay of juvenile hormone release, the effect of two native D. punctata RFamides, an FLRFamide (Leucomyosuppressin) and an FIRFamide were examined. The latter, for which the sequence (SKPANFIRFamide) is reported here, stimulated juvenile hormone release but acted only on corpora allata from females at the end of vitellogenesis (day 6). The interaction of these two RFamides and three D. punctata allatostatins, Dippu-AST 2, 5, and 7 were similarly examined. Only Dippu-AST 2 stimulated release of RFamides from the corpora allata and only on day 6 whereas both RFamides were able to attenuate the inhibitory activity of Dippu-AST 2.

Methyl farnesoate and juvenile hormone production in embryos of Diploptera punctata in relation to innervation of corpora allata and their sensitivity to allatostatin

Corpora allata (CA) of embryos of Diploptera punctata have been previously shown to produce JH III. We have re-examined sesquiterpenoid biosynthesis throughout embryonic development and have found that early embryos produce both methyl farnesoate (MF) and JH III; as development proceeds, less MF and more JH is produced. The cockroach allatostatin peptide Dippu-allatostatin (AST) 7 inhibits sesquiterpenoid production by CA of mid to late embryos whereas it exerts a dose-dependent stimulatory effect in early embryos. This stimulatory effect is particularly apparent on MF biosynthesis. CA become innervated by allatostatin-containing nerves in early embryos (35% development). Shortly thereafter, the allatostatin-containing innervation of the CA appears complete.

Protective effect of verbascoside on 1-methyl-4-phenylpyridinium ion-induced neurotoxicity in PC12 cells

The neuroprotective effects of verbascoside, one of phenylpropanoid glucoside isolated from the Chinese herbal medicine Buddleja officinalis Maxim, on 1-methyl-4-phenylpyridinium ion (MPP(+)) induced apoptosis and oxidative stress in PC12 neuronal cells were investigated. Treatment of PC12 cells with MPP(+) for 48 h induced apoptotic death as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, the activation of caspase-3 measured by the caspase-3 activity assay kit, the reduction in mitochondrial membrane potential with laser scanning confocal microscopy and the increase in the extracellular hydrogen peroxide level. Simultaneous treatment with verbascoside markedly attenuated MPP(+)-induced apoptotic death, increased extracellular hydrogen peroxide level, the activation of caspase-3 and the collapse of mitochondrial membrane potential. These results strongly indicate that verbascoside may provide a useful therapeutic strategy for the treatment of oxidative stress-induced neurodegenerative disease such as Parkinson's disease.

Carcinogenic potential of duodenal reflux juice from patients with long-standing postgastrectomy

AIM: To determine whether study on the carcinogenic potential of reflux juice from patients with remote gastrectomy could clarify the inherent relationship between duodenal reflux and gastric stump cancer.

METHODS: A total of 37 reflux juice samples (13 Billroth I, 24 Billroth II) were employed in the present study. A two-stage transformation assay using BALB/c 3T3 cells was carried out to test the initiating or promoting activity of these samples.

RESULTS: Two of 18 (11.1%) reflux samples exerted initiating activities, whereas 9/19 (47.4%) samples enhanced the MNNG-initiating cell transformation, suggesting the duodenal reflux juice might more frequently possess the tumor-promoter activity (P = 0.029). In addition, there was no difference in initiating activities of the samples irrespective of surgical procedures (P = 0.488), while Billroth II samples exhibited stronger tumor-promoter activity than Billroth I samples (P = 0.027). Furthermore, the promoter activities were well correlated with the histological changes of the stomas (r_s = 0.625, P = 0.004), but neither their cytotoxicities nor initiating activities had this correlation (Probabilities were 0.523 and 0.085, respectively).

CONCLUSION: The duodenal reflux juice from patients with remote postgastrectomy did have carcinogenic potential, and suggested that tumor-promoting activity should principally account for the high incidence of gastric cancer in gastrectomy patients. In contrast, it is difficult to explain the high stump-cancer incidence with the "N-nitroso compounds" theory-a popular theory for the intact stomach carcinogenesis, and it seemed to be justified to focus chemoprevention of this cancer on the tumor-promoting potential of reflux juice.

Effect of isolation of periosteum and dura on the healing of rabbit calvarial inlay bone grafts

Little is understood about the role of the recipient site in the revascularization and incorporation of autogenous inlay bone grafts in the craniofacial skeleton. Clinical experience demonstrates that secondary complex cranial vault reconstruction performed with scarred avascular dura or poor soft-tissue coverage may undergo significant resorption, thus compromising the aesthetic outcome. This study was designed to determine the effect of isolating autogenous orthotopic inlay calvarial bone grafts from the surrounding dura and/or periosteum on graft revascularization, healing, and volume maintenance in the adult rabbit. Adult rabbits were randomized into four groups (n = 10 per group); in each rabbit, the authors created a circular, 15-mm in diameter, full-thickness cranial defect followed by reconstruction with an autogenous calvarial bone graft, which was replaced orthotopically and held with microplate fixation. Silicone sheeting (0.5 mm thickness) was used to isolate the dura (group II), the periosteum (group II), or both dura and periosteum (group IV) from the graft interface. No silicone was placed in group I. Animals were killed 10 weeks postoperatively, and calvaria were harvested to assess graft surface area, morphology, quantitative histology, fluorochrome staining, and revascularization. Grafts isolated from both the dura and periosteum exhibited significant decreases in total bone (cortical and trabecular) surface area, blood vessel count, and interface healing compared with nonisolated control grafts. Isolation of either the dura or periosteum significantly (p < 0.05) decreased blood vessel count but had no significant effect on interface healing. Isolation of the dura alone was associated with a significant (p < 0.05) decrease in graft cross-sectional surface area and dural cortical thickness compared with nonisolated control grafts, but this effect was not observed when the periosteum alone was isolated. Quantitative histology performed 10 weeks after surgery indicated that graft isolation was associated with increased marrow fibrosis and necrosis compared with nonisolated controls; it also demonstrated evidence of increased activity in bone remodeling (osteoblast and osteocyte count, new trabecular bone, and surface resorption). Triple fluorochrome staining suggested increased bone turnover in the nonisolated grafts compared with isolated grafts at 1 and 5 weeks postoperatively. This study demonstrates that isolating a rabbit calvarial inlay autogenous bone graft from the dura and/or periosteum results in significantly (p < 0.05) decreased revascularization, interface healing, and cross-sectional areas of amount of mature bone compared with nonisolated control grafts 10 weeks after surgery. At this time point, histologic examination demonstrates a paradoxical increase in bone remodeling in isolated bone grafts compared with controls. It is possible that the inhibition of revascularization results in a delayed onset of the remodeling phase of graft incorporation. However, in the model studied, it is not known whether the quantitative histologic and morphometric parameters measured in these isolated grafts exhibit a "catch-up" phenomenon at time points beyond 10 weeks after surgery. The results of this study emphasize the importance of a healthy recipient site in the healing and incorporation of calvarial bone grafts but stress the need for further investigation at later time points.

The polymeric immunoglobulin receptor translocates pneumococci across human nasopharyngeal epithelial cells

The polymeric immunoglobulin receptor (pIgR) plays a crucial role in mucosal immunity against microbial infection by transporting polymeric immunoglobulins (pIg) across the mucosal epithelium. We report here that the human pIgR (hpIgR) can bind to a major pneumococcal adhesin, CbpA. Expression of hpIgR in human nasopharyngeal cells and MDCK cells greatly enhanced pneumococcal adherence and invasion. The hpIgR-mediated bacterial adherence and invasion were abolished by either insertional knockout of cbpA or antibodies against either hpIgR or CbpA. In contrast, rabbit pIgR (rpIgR) did not bind to CbpA and its expression in MDCK cells did not enhance pneumococcal adherence and invasion. These results suggest that pneumococci are a novel example of a pathogen co-opting the pIg transcytosis machinery to promote translocation across a mucosal barrier.

Hospital autopsies: still valuable in their traditional role but in need of reform

In 1997, 158 autopsies were performed at Charleston Area Medical Center, a community-based, teaching tertiary care center. The autopsies revealed 29 (18.4%) clinically undiagnosed principal causes of death, of which 79% were considered treatable. The five leading undiagnosed causes were: infarctions, 27.6%; malignant neoplasms, 17.2%; pulmonary emboli, 13.8%; dissecting or ruptured aortic aneurysms, 13.8%; and genetic or congenital disorders 10.2%. These results were significantly different from those reported from some other major tertiary care centers. Reports were completed in 5-302 days (average 59, median 32 days). For more than 40 (25%) of these autopsies, the purpose was only to confirm specific disorders such as occupational injury, which can be accomplished by a highly selective, cost-effective posthumous analysis. In summary, an autopsy in today's high-technology era is still useful, however, the high cost, long length of reporting time, and number of clinically non-enlightening cases are a reasons to reform both the format and procedure in which these procedures are conducted.

Molecular and cellular mechanisms for microbial entry into the CNS

A number of pathogenic microbes including neuroinvasive viruses, bacteria and parasites are capable of entry into the central nervous system (CNS) and cause a variety of clinical manifestations. The cellular and molecular mechanisms for the CNS invasion have been extensively studied in the last two decades. Viruses invade neurons and thereby cause encephalitis or peripheral neuritis, while bacteria enter the cerebrospinal fluid (CSF) and cause meningitis. In contrast, the mechanisms for parasitic neuroinvasion are much more complex and less clear. The capabilities that enable these elite subsets of pathogens to engineer uptake into the CNS will be the subject of this review.

Effects of an allatostatin and a myosuppressin on midgut carbohydrate enzyme activity in the cockroach Diploptera punctata

Neuropeptides of the cockroach allatostatin (AST) family are known for their ability to inhibit the production of juvenile hormone by the corpora allata of cockroaches. Since their discovery, they have also been shown to modulate myotropic activity in a range of insect species as well as to act as neurotransmitters in Crustaceans and possibly in insects. The midgut of cockroaches contains numerous endocrine cells, some of which produce AST whereas others produce the FMRFamide-related peptide, leucomyosuppressin (LMS). We have determined if ASTs and LMS are also able to influence carbohydrate-metabolizing enzyme activity in the midgut of the cockroach, Diploptera punctata. Dippu-AST 7 stimulates activity of both invertase and alpha-amylase in a dose-dependent fashion in the lumen contents of ligatured midguts in vitro, but not in midgut tissue, whereas the AST analog AST(b)phi2, a cyclopropyl-ala, hydrocinnamic acid analog of Dippu-AST 6, has no effect. Leucomyosuppressin also stimulates enzyme activity in lumen contents only, although the EC50 is considerably greater than for Dippu-AST. Dippu-AST is also able to inhibit proctolin-induced contractions of midgut muscle, and this action had already been described for LMS [18]. Thus, in this organ, AST and LMS have at least two distinct physiological effects.

Pneumococcal licD2 gene is involved in phosphorylcholine metabolism

Phosphorylcholine is an important bioactive adduct to the teichoic acid (TA) and lipoteichoic acid (LTA) of the surface of Streptococcus pneumoniae. We have identified and characterized a genetic locus lic that is required for phosphorylcholine metabolism in S. pneumoniae. The pneumococcal lic locus consists of eight genes, licA, licB, licC and licD1, licD2 and three additional open reading frames. Pneumococcal licA, licB, licC, licD1 and licD2 have significant sequence similarity to licA, licB, licC and licD of Haemophilus influenzae. Mutation of licD2 led to decreased [3H]-choline uptake, aberrant migration of LTA chains in SDS-PAGE gels, loss of several surface proteins, and a phase-locked hypertransparent colony phenotype. Moreover, the licD2- mutant falled to undergo lysis after treatment with penicillin at high cell density and showed decreased transformation competence. Finally, the licD2- mutant demonstrated decreased adherence to the human type II alveolar cells, reduced nasopharyngeal colonization in infant rats, as well as significantly impaired virulence upon intraperitoneal challenge of CF1 mice. Identification of the lic genes in the pneumococcus will facilitate further characterization of the role of surface choline in microbial physiology and pathogenesis.

Studies on the determination of diacetyl guanfubase A concentration in rabbit plasma and pharmacokinetics

A gas chromatographic method for monitoring diacetyl guanfubase A in plasma is described. The procedure involved a single solvent extraction of drug from rabbit plasma into ethyl acetate with guanfubase A as an internal standard. The extract was analyzed subsequently on a gas chromatograph equipped with a hydrogen flame ionization detector. The recovery was 86.43% +/- 6.90% (+/- SD); the RSD of within-day and between-day was 2.81%-5.26% and 5.22%-8.24%, respectively; the regression line was linear over the concentration range of 25-200 micrograms/mL, the limit of detection was 10 micrograms/mL. No endogeneous interference was found in chromatograms of the biological samples. This method was applied to the pharmacokinetic study of diacetyl guanfubase A in rabbits.