Electroporation in Giardia lamblia.
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Animals↗
Biomedical subjects
A L Wang
Publications and source records attributed to A L Wang.
Giardiavirus-resistant Giardia lamblia lacks a virus receptor on the cell membrane surface.
Giardia lamblia virus (GLV) is a small nonenveloped double-stranded RNA virus that infects specifically the parasitic protozoan G. lamblia. Among the many collected strains of G. lamblia, a few turn out to be highly resistant to the virus infection. Two of these strains, Ac and JH, were subjected to electroporation with the RNA from GLV-infected G. lamblia WB strain. Subsequent studies indicated the presence of GLV double-stranded RNA and GLV protein in the electroporated and propagated cells. Virus particles, released by the transfected cells into the culture medium, were capable of infecting the virus-sensitive G. lamblia WB strain. When the WB cells were incubated with GLV at 4 degrees C and treated with the bifunctional cross-linking reagent disuccinimidyl suberate, little GLV protein was detectable inside the cells by immunofluorescent staining. However, patches of fluorescent granules were found on the membrane surface of the cells, suggesting cross-linking of the viruses with a certain membrane component(s). Similar treatment of the resistant strains Ac and JH showed no fluorescence either inside or outside of the cells. Two other closely related parasitic protozoa, Tritrichomonas foetus and Trichomonas vaginalis, cannot be infected by GLV via either viral infection or RNA transfection. The [35S]cysteine-labeled protein profiles in Triton X-114 extracts of G. lamblia WB, Ac, and JH were compared. The profile of the WB strain differs clearly from that of Ac and JH. It remains to be seen, however, whether this difference is related at all to the different susceptibilities to GLV infection.
Animals↗
Pharmacodynamics of chimeric glycoprotein IIb/IIIa integrin antiplatelet antibody Fab 7E3 in high-risk coronary angioplasty.
BACKGROUND: Thrombosis has been implicated as central to the clinical complications of coronary angioplasty (PTCA). Chimeric monoclonal 7E3 Fab (c7E3 Fab) is the first of a new class of antiplatelet drugs directed at the platelet glycoprotein IIb/IIIa integrin. This study was performed to determine the pharmacodynamics of c7E3 Fab administration during PTCA and to gain an initial clinical experience with this novel agent. METHODS AND RESULTS: The study was a multicenter, open-label, dose-escalation study conducted in two stages. Enrollment included 56 patients scheduled for elective PTCA who were estimated to be at moderate to high risk of sustaining ischemic complications. All patients were given aspirin and heparin. The study drug was given at least 10 minutes before PTCA. In stage 1, increasing bolus doses of c7E3 Fab were given to 15 patients; a bolus dose of 0.25 mg/kg was found to result in blockade of > 80% of the receptors and reduce platelet aggregation to < 20% compared with baseline, establishing this dose as that necessary to sufficiently suppress platelet activity. In stage 2, additional c7E3 Fab was administered by continuous infusion to 32 patients for progressively longer periods of time (up to 24 hours) to confirm that platelet inhibition could be maintained with prolonged drug infusion. Also, 9 patients otherwise meeting entry criteria were given placebo. There were no thrombotic events among patients receiving c7E3 Fab. Overall procedural and clinical success and complication rates as well as rates of bleeding were statistically similar among groups. However, minor bleeding was more frequent with administration of the active drug. CONCLUSIONS: The novel antiplatelet agent c7E3 Fab can be administered during PTCA in combination with aspirin and heparin. Suppression of platelet activity is dose dependent and can be maintained for up to 24 hours. Further evaluation will be required to determine the extent of improvement in ischemic complication and restenosis rates and to provide additional insight into the safety profile of this potent monoclonal platelet antibody.
Abciximab↗
[Effect of xiaoyu pian on new platelet aggregation defect].
The Xiaoyu pian (XYP, mainly consisted of prunus persica, Carthamus tinctorius, Glycyrrhiza uralensis, etc) was used to treat patients with new platelet aggregation defect. Patients were divided into 2 groups, the TCM group (72 cases) treated with XYP and the control group (65 cases) treated with vitamin C and P and/or adrenosem for at least 3 months. The results showed that marked effective rate was 87.5% in TCM group and 35.4% in control group (chi 2 = 39.7, P < 0.01); the recovery rate of platelet was 91.8% in the former and 10.3% in the latter (chi 2 = 71.4, P < 0.01); the recurrence rate of follow-up (6 months after treatment) was 30.8% in the former and 82.1% in the latter (chi 2 = 19.2, P < 0.01). The difference between two groups was very significant. The results suggested that XYP could regulate the hemostatic action and the platelet aggregation function. It is worthwhile to use XYP as an hemostatic clinically.
Adolescent↗
[Gene variation in the pre-C region of hepatitis B virus].
We examined the serum HBV DNA of the chronic hepatitis B patients with positive c-system by using polymerase chain reaction (PCR). Twenty samples of HBeAg(+)/anti-HBe(-) positive PCR products and 20 samples of HBeAg(-)/anti-HBe(+) positive PCR products were selected. These products were dot-hybridized by synthetic HBV pre-C region geno oligonucleotide probes M0 (non mutated), M1 (one) point-mutated), M2 (two point-mutated). The results thus obtained showed that for 85% (17/20) of the chronic hepatitis patients with HBeAg(-)/anti-HBe(+), point mutation occurred at the 1,896th nucleotide, resulting in the stop codon, and half (10/20) of the patients suffered two points mutation. The direct determination of the sequence of some mutation PCR products selected proved the existence of point mutation. The result indicated that the natural conversion of hepatitis patients' HBeAg(+) to anti-HBe(+) may have resulted from the genovariation in the pre-c region of HBVDNA rather than from the decreased of virus replication.
Base Sequence↗
[Inhibition of hepatitis B viral gene expression by antisense phosphrothioate oligonucleotides].
Hep G2 cells transfected with HBV genomes were used to study the inhibitory effect of antisense phosphrothiate oligodeoxynucleotides on HBsAg and HBeAg production. The synthetic antisense 15-s-oligomers against the cap site of mRNA transcribed from the SPII promoter and regions of the translational initiation site of the S gene showed a dose-dependent and sequence-specific inhibitory effect on HBV gene expression between concentrations of 1.0-5.0 mumol/L. But the oligomers directed on the middle site of the S gene exerted little effect on HBsAg and HBeAg expression as well as the non-complementary random sequence control. The cells remained viable throughout the experiments and no morphological abnormalities and cytotoxicity were observed with antisense S-oligomers at concentrations below 20.0 mumol/L. These results suggest a therapeutic potential for antisense oligonucleotides in the treatment of patients who are chronically infected with HBV.
Base Sequence↗
Giardiavirus double-stranded RNA genome encodes a capsid polypeptide and a gag-pol-like fusion protein by a translation frameshift.
Giardiavirus is a small, nonenveloped virus comprising a monopartite double-stranded RNA genome, a major protein of 100 kDa, and a less abundant polypeptide of 190 kDa. It can be isolated from the culture supernatant of Giardia lamblia, a parasitic flagellate in human and other mammals, and efficiently infects other virus-free G. lamblia. A single-stranded copy of the viral RNA can be electroporated into uninfected G. lamblia cells to complete the viral replication cycle. Giardiavirus genomic cDNA of 6100 nt was constructed and its sequence revealed the presence of two large open reading frames that are separated by a -1 frameshift and share an overlap of 220 nt. The 3' open reading frame contains all consensus RNA-dependent RNA polymerase sequence motifs. A heptamer-pseudoknot structure similar to those found at ribosomal slippage sites in retroviruses and yeast killer virus was identified within this overlap. Immunostudies using antisera against synthesized peptides from four regions in the two open reading frames indicated that the 100- and 190-kDa viral proteins share a common domain in the amino-terminal region. But the 190-kDa protein makes a -1 switch of its reading frame beyond the presumed slippage heptamer and is therefore a -1 frameshift fusion protein similar to the gag-pol fusion protein found in retroviruses.
Amino Acid Sequence↗
Asian/non-Asian transcultural tricyclic antidepressant psychopharmacology: a review.
1. Transcultural psychopharmacology is a discipline that seeks to determine the relative importance of society, culture, environment, genetics, and biophysiology on the prescribing and metabolism of, and response to psychotherapeutic medications. 2. Studies and surveys comparing psychotropic medication use in Asian and non-Asian populations suggest that differences may exist in drug dosage requirements, plasma drug concentrations corresponding to therapeutic and toxic effects, and the incidence and severity of adverse drug reactions. 3. This paper reviews and critiques the published controlled studies on Asian/non-Asian transcultural tricyclic antidepressant psychopharmacology, provides guidelines for the use of psychotropic medications in Asian populations, and offers suggestions for future transcultural studies. 4. Anecdotal reports suggest that differences exist between Asian and non-Asian populations in the pharmacokinetics of tricyclic antidepressants. Controlled studies have not consistently supported this view. 5. Studies with larger sample sizes and more rigorous controls are needed to determine if such differences do, in fact, exist.
Antidepressive Agents, Tricyclic↗
Nicotine is responsible for airway irritation evoked by cigarette smoke inhalation in men.
To determine whether nicotine is involved in evoking the irritant effects of cigarette smoke in airways, we studied the responses to inhalation of a single puff (30 ml) of three types of smoke (high nicotine, low nicotine, and gas phase) in healthy male nonsmokers. After the upper airways were locally anesthetized, the subjects, breathing through a mouthpiece, were instructed to signal the detection and the intensity of airway irritation with a push-button device. Inhalation of high-nicotine smoke consistently triggered an intense airway irritation in the lower neck and upper chest region; the total number of push-button signals generated in the first 5 s was 6.61 +/- 0.87 (mean +/- SE, n = 12), with a detection latency of 0.93 +/- 0.11 s. By contrast, inhalation of low-nicotine and gas phase smoke either was not detected or caused only very mild irritation (0.89 +/- 0.4 and 0.36 +/- 0.22, respectively). In addition, the intensity of smoke-induced airway irritation was markedly reduced after premedication with aerosolized hexamethonium, a nicotinic receptor antagonist (P < 0.01, n = 8). Furthermore, inhalation of nicotine aerosol also immediately evoked intense airway irritation and coughs (n = 5). Thus we conclude that the airway irritation evoked by inhaling cigarette smoke results from an activation of sensory endings located in the central airways and nicotine is the primary agent responsible for this action.
Adult↗
Bronchoconstriction and delayed rapid shallow breathing induced by cigarette smoke inhalation in anesthetized rats.
Bronchomotor and ventilatory responses to inhalation of cigarette smoke (50% concentration, 6 ml) were studied in anesthetized and vagotomized Sprague-Dawley rats. Low-nicotine cigarette smoke did not cause any detectable delayed response, whereas high-nicotine cigarette smoke induced rapid, shallow breathing, and a marked increase in airway resistance (RL). The increase in f reached a peak (delta f = 43 +/- 8%) at the 5th breath after the onset of smoke inhalation, preceding both the decrease in VT (delta VT = -27 +/- 4%) and the increase in RL (delta RL = 89 +/- 19%); the latter 2 reached their peaks at approximately the 10th breath, displaying a similar temporal pattern of responses between them. The bronchomotor response to high-nicotine cigarette smoke was slightly attenuated but not prevented by prior administration of isoproterenol (0.2 mg/kg, intravenously [iv]), nor was the smoke-induced rapid, shallow breathing. In contrast, prior administration of mecamylamine (0.9 mg/kg, iv) completely abolished both the bronchomotor and ventilatory responses to smoke inhalation, indicating that nicotine is the primary causative agent responsible for these changes.
Airway Resistance↗
The course of giardiavirus infection in the Giardia lamblia trophozoites.
The subcellular distribution of Giardia lamblia virus RNA in infected G. lamblia trophozoites was examined by in situ hybridization using biotinylated DNA probe and riboprobe. In G. lamblia Portland I strain, which is chronically infected by G. lamblia viruses, the viral RNA was detected in the cytoplasm as well as in the twin nuclei. When riboprobe was used to examine the course of virus infection in WB strain, accumulation of viral RNA was detected only in the cytoplasm prior to the first 72 hr of infection. Using DNA probe, further accumulation of viral RNA in increasing number of cells occurred after the 72nd hr of infection, with the RNA found in both the cytoplasm and nuclei. Eventually, the cell nuclei showed damaged morphology that deteriorated rapidly toward the final stage of infection. These observations indicate that early phase of viral RNA replication may take place in the cytoplasm of infected G. lamblia, but the nuclei are also involved during the late phase of viral replication.
Animals↗
Viruses of parasitic protozoa.
Recently, specific viruses have been identified among the parasitic protozoa Trichomonas vaginalis, Giardia lamblia, Leishmania braziliensis, the Eimeria spp and the Babesia spp. These viruses share many features: they are all RNA viruses and most, if not all, doublestranded (ds) RNA viruses with nonsegmented genomes ranging between 5 and 7 kilobases (kb); they are spherical or icosahedral with an average diameter of 30-40 nm. The giardiavirus is one of the best characterized and can infect virus free G. lamblia trophozoites in its freed, pure form. The replicative intermediate of the giardiavirus genome has been isolated from infected cells, and can be introduced into G. lamblia by electroporation to produce giardiavirus, thus raising the possibility of its being used as a specific genetic transfection vector for the parasite.
Journal Article↗
Viruses of the protozoa.
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Amino Acid Sequence↗
Nifedipine: bite-and-swallow administration.
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Administration, Oral↗
Fibronectin in patients with chronic renal failure undergoing dialysis.
Fibronectin (FN) levels were determined in 64 cases with chronic renal failure (CRF), some of whom were undergoing dialysis. FN levels were 14.9 +/- 7.6 mg/dl in CRF (n = 20), 13.4 +/- 4.3 mg/dl in patients on continuous ambulatory peritoneal dialysis (CAPD) (n = 20) and 16.7 +/- 7.2 mg/dl in patients on hemodialysis (HD) (n = 24). All the levels were significantly lower than in normal subjects (23.1 +/- 4.6 mg/dl). Serum FN was compared with some nutritional indices. Positive correlations were found between serum FN and nitrogen balance (BN), serum prealbumin (PreA) and transferrin (Tf) in all the patients. With serum albumin (Alb), however, this correlation was only found in patients undergoing dialysis. Negative correlations were found between serum FN and the ratio of serum urea to serum creatinine (Surea/Scr) in CAPD and HD patients. In 10 CAPD patients, the low serum FN levels went up after increased protein intake. This indicates that it was the result of malnutrition due to decreased protein intake. Serum FN level reflects a negative BN earlier and better than serum PreA, Tf and Alb. It is a sensitive, reliable and simple index for judging the nutritional protein status and the effect of nutritional treatment in patients with CRF undergoing dialysis.
Adolescent↗
[Changes in the levels of human platelet membrane glycoproteins in patients with a new-type defect of platelet aggregation].
Labeled avidin-biotin (LAB)-enzyme linked immunosorbent assay (ELISA) for quantitative measurement of the levels of human platelet membrane glycoproteins (GPs) Ib, IIb and IIIa was developed by using a group of murine monoclonal antibodies raised against human platelet membrane GPs. The contents of the GPs Ib, IIb and IIIa in patients with a new-type defect of platelet aggregation were detected and found to be in normal range. However, the amounts of GPs IIb and IIIa before washing in patients were significantly decreased in these patients when compared with those in controls (P less than 0.01), while after washing, normal levels could be obtained. The results reported have support the hypothesis that the pathogenesis of this defect in platelet aggregation seems not to be associated with the abnormality of the levels of GPs, but is a result of abnormal factor existing in the plasma. Further investigation on the properties of the factor is in progress.
Blood Platelet Disorders↗
A single-stranded RNA copy of the Giardia lamblia virus double-stranded RNA genome is present in the infected Giardia lamblia.
An isolate of Giardia lamblia infected with the double-stranded RNA virus (GLV) has two major species of RNA that are not present in an uninfected isolate. One of these species is the previously characterized double-stranded RNA genome of GLV (1). The second species of RNA appears to be a full length copy of one strand of the double-stranded RNA genome. This full length single-stranded RNA is not present in viral particles isolated from the growth medium. The cellular concentration of the single-stranded RNA changes during exponential and stationary phases of cell growth in a fashion consistent with a viral replicative intermediate or mRNA. The single-stranded species does not appear to be polyadenylated.
Animals↗
Identification of Giardia lamblia isolates susceptible and resistant to infection by the double-stranded RNA virus.
The presence or absence of the Giardia lamblia double-stranded RNA virus (GLV) was surveyed among 38 axenic isolates of G. lamblia derived from both humans and animals. Of the 28 isolates lacking the virus, 19 could readily be infected by the virus. The remaining 9 isolates proved to be resistant to GLV infection even when the ratio between virus to parasite reached as high as 10(6) to 1. Evidence is also presented indicating that there are at least two "Portland 1" strains being used by the current scientific community, one containing the virus and the other lacking the virus.
Animals↗