Up-regulation of dopamine D1-receptors in the brain of 28-day-old rats exposed to the delta (delta) opioid agonist SNC80 during the preweaning period

Twenty-eight-day-old rats exposed to the delta (delta) opioid receptor agonist SNC80 during the preweaning period exhibited a significant increase in the density and apparent dissociation constant of striatal dopamine D1-receptors. There were no significant effects on the binding characteristics of striatal D2-receptors or on D1- or D2-receptors in the nucleus accumbens. The results suggest that delta-opioid receptor mechanisms might be involved in certain neurological changes observed in offspring of mother addicted to opioids during nursing.

Inhibition effect of shengma-gegen-tang on measles virus in Vero cells and human peripheral blood mononuclear cells

Shengma-Gegen-Tang has long been used against measles virus in human peripheral blood mononuclear cells (PBMC) as well as in Vero cells. One hundred micrograms/ml Shengma-Gegen-Tang in PBMC displays significant anti-measles activity, whereas the same concentration in Vero cells does not. After eight days of infection, the release of virus is significantly suppressed by Shengma-Gegen-Tang in the case of PBMC. In addition, Shengma-Gegen-Tang has a selective stimulation to the secretion of cytokine TNF-alpha in PBMC. Time kinetic analysis indicated that the stimulation of secretion was rapid and could be detected only 2 hrs following the treatment of the PBMC. It rose to an optimal level in 8-12 hrs. These findings suggest that the magnification of anti-measles virus activity of this agent is lymphocyte dependent and may well be mediated by TNF-alpha.

Stimulating dopamine D1 receptors increases the locomotor activity of developing rats

To determine the role of dopamine D1 receptors in the locomotor activity of developing rats, male offspring were habituated to an animal activity monitor and were then injected with the dopamine D1 receptor antagonist, SCH 23390 (R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl- 2,3,4,5-tetrahydro-(1 H)-3-benzazepine), or vehicle and returned to the activity monitors. 30 min later, they were injected with the dopamine D1 receptor agonist, SKF 38393 (R(+)-1-phenyl-2,3,4,5-tetrahydro-(1 H)-3-benzazepine-7,8-diol), or vehicle and were again placed in the activity boxes where their locomotor activity was monitored individually for 1 h. The litter was used as the unit for statistical analyses. There was a significant increase in the locomotor activity of 10- and 21-day-old offspring injected with SKF 38393. This effect was antagonized by pretreatment with SCH 23390. These data provide the strongest evidence to date that stimulation of dopamine D1 receptors increases the locomotor activity of habituated developing rats.

Identification of serotypes of Rickettsia tsutsugamushi by nested polymerase chain reaction

Nested polymerase chain reaction (PCR) was applied to identify the serotypes of Rickettsia tsutsugamushi isolated from patients. The primers used for PCR were based on the nucleotide sequences encoding a 56 kDa antigen of rickettsiae. Comparing to the conventional immunofluorescence assay (IFA), which displays a considerable degree of cross-reactivity among different species, the result obtained suggests that the polymerase chain reaction method is much more reliable than IFA.

ELISA-based colorimetric detection of Rickettsia tsutsugamushi DNA from patient sera by nested polymerase chain reaction

A rapid diagnostic system for scrub typhus was established using colorimetric detection of nested polymerase chain reaction (PCR). This system relied on binding the amplified DNA via a sequence in one of oligodeoxyribonucleotide to the DNA-binding protein GCN4 coated on the well of a micotiter dish. The primer pairs used for the nested PCR were designed on the basis of the homologous nucleotide sequence of the gene that encodes the 56 kDa antigen of serovariants. With this colorimetric PCR, diagnosis can be performed easily from serum samples of patients before the antibody titer increases or in the early stage of the disease. Furthermore, these positive results are able to be confirmed by pathogenic isolation.

[Isolation of Rickettsia tsutsugamushi from the blood samples of patients in Taiwan]

Scrub typhus, an acute febrile eruptive disease caused by Rickettsia tsutsugamushi, is one of the most commonly reported communicable diseases in Taiwan. However, information about the epidemic trends of scrub typhus in Taiwan is still very limited. Therefore, this study was performed to isolate the causative agent and determine the prevalence of three different serotypes. From June 1992 to December 1994, lymphocyte cell cultures were grown from different regions of Taiwan. Cell cultures were assayed for R. tsutsugamuhi via immuno-fluorescence, using antisera against Gillian, Karp and Kato strains. Thirty-three of the specimens were positive for R. tsutsugamushi, including one from Keelung, 23 from Taitung, 2 from Kinmen and 7 from Lienjan. Of these, 15 were classified as Gillian-related types, 10 were Karp-related types and 8 were not positively classified. These results indicate Gilliam-and Karp-related serotype are more prevalent than the Kato-related serotype in Taiwan.

Characterization of an open reading frame involved in site-specific integration of filamentous phage Cf1t from Xanthomonas campestris pv. citri

Cf1t is a single-stranded DNA filamentous phage; a 1.9-kb segment of DNA from Cf1t was found to be responsible for site-specific integration into Xanthomonas campestris pv. citri (XW47), in the absence of any Xanthomonas origin of replication. Deletion analysis and introduction of amber stop codons into this fragment from Cf1t revealed an open reading frame (ORF344) which was involved in the integration function. The predicted amino-acid sequence of ORF344 bears no homology with conserved sequences of the integrase family.

Detection of Rickettsia tsutsugamushi specific DNA from the lymphocyte of patients by polymerase chain reaction

Polymerase chain reaction was used to detect Rickettsia tsutsugamushi specific DNA from the lymphocytes of patients in the acute phase of the disease. The primers used in the PCR were based on the nucleotide sequences of gene encoding of the 56 kDa antigen of the Gilliam strain. The PCR product is a 78 bp fragment which can be hybridized by the 78 bp DNA probe of the Gilliam strain. Comparison of the results obtained by polymerase chain reaction, immunofluorescent assay and cell culture suggests that the polymerase chain reaction method is the most sensitive one among the three in diagnosis of scrub typhus.

Altered neurochemical and behavioral development of 10-day-old rats perinatally exposed to the kappa opioid agonist U-50,488H

To determine the effects of chronic perinatal exposure to a kappa opioid agonist on the neurochemical and motor development of rat offspring, osmotic pumps containing trans-(+-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]- benzeneacetamide methane sulfonate (U-50,488H), 79 mg/ml, or vehicle were implanted into anesthetized pregnant female rats. On postnatal day 10, the nucleus accumbens (NAc) of male offspring were dissected and assayed for dopamine (DA) receptors. Male offspring from other litters were injected subcutaneously with the D2 agonist quinpirole, 0.05 mg/kg, the D1 agonist SKF 38393, 10 mg/kg, or 0.9% saline vehicle. Their locomotor activity was then monitored for 1 h. The binding of DA D1 and D2 receptors was significantly increased by 26% and 90%, respectively, in the NAc of 10-day-old offspring exposed to U-50,488H. There was a significant, 52%, decrease in the locomotor response to quinpirole by 10-day-old offspring exposed to U-50,488H. Exposure to U-50,488H had no significant effect on the locomotor response to SKF 38393 at this age. The results indicate that perinatal exposure to a kappa agonist alters the development of brain DA receptors and DA-mediated motor behavior. The data suggest that motor deficits observed in offspring exposed to opioids in utero may involve brain kappa opioid receptor mechanisms.

Identification and nucleotide sequence analysis of an open reading frame involved in high-frequency conversion of turbid to clear plaque mutants of filamentous phage Cf1t

Clear plaque mutants (Cf1c) isolated from the temperate filamentous phage Cf1t occurred at a frequency of approximately 10(-3). The pahge yield from Cf1c-infected cells was higher than that from Cf1t-infected cells. Results of spot complementation tests implied that the turbid plaque phenotype is dominant. DNA fragment substitution studies indicated that a NcoI/KpnI fragment of 591 bp was responsible for the determination of plaque turbidity. Sequence data from four Cf1c isolates revealed base pair alterations and a deletion located in the upstream region of an open reading frame (ORFII) which might encode a 18.2-kDa protein. When the ORFII in Cf1t was disrupted by a frameshift mutation, this recombinant phage formed clear plaques. These observations suggest that ORFII may participate in the formation of turbid plaques. ORFII does not show significant homology with the sequence of f1 gpII, gpV, or other known phage proteins.