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Biomedical subjects

J Tang

Publications and source records attributed to J Tang.

At least 199 records · Page 11Linked to original sources
PubMed1999

Gene suture--a novel method for intramuscular gene transfer and its application in hypertension therapy.

In this report, reporter gene beta-galactosidase (LacZ) was chosen to compare two different intramuscular gene transfer methods, direct injection and gene suture. Evidence showed that gene suture can produce a higher foreign gene express efficiency in skeletal muscle compared with the direct injection method. The highly efficient eukaryotic expressing vectors of human atrial natriuretic factor (ANF) were constructed (pcD2/pAdVAntage/hANF and pcDNA3/hANF), and in vivo ANF gene delivery was performed by intramuscular gene suture. The effects of ANF gene transfer on blood pressure and renal sodium and water excretion were studied in three models of hypertensive animals. Results showed that a marked decrease of mean arterial pressure (MAP) and a significant increase of urine volume and urinary sodium excretion was produced in rats receiving the hANF construct due to the local expression of ANF and its secretion into plasma. Taken together, these results indicate that gene suture may represent a novel gene delivery modality in gene therapy.

Animals↗
PubMed1999

Use of propofol for office-based anesthesia: effect of nitrous oxide on recovery profile.

STUDY OBJECTIVE: To evaluate the effect of nitrous oxide (N2O) on the recovery profile and the incidence of postoperative nausea and vomiting (PONV) after office-based surgery performed under propofol anesthesia. DESIGN: Prospective, randomized, single-blind study. SETTING: Office-based surgical center. PATIENTS: 69 ASA physical status I, II, and III healthy, consenting outpatients undergoing superficial surgical procedures lasting 15 to 45 minutes. INTERVENTIONS: After a standard propofol induction (1.5 mg.kg-1 i.v.), anesthesia was initially maintained with propofol, 100 micrograms.kg-1.min-1 i.v., in combination with either air or N2O 65% in oxygen. The propofol infusion rate was subsequently varied to maintain an adequate depth of anesthesia. All patients received local anesthetic infiltration prior to the surgical incision, as well as during the operation. No prophylactic antiemetics were administered. MEASUREMENTS AND MAIN RESULTS: Recovery times and the incidences of PONV were recorded during the first 24 hours after surgery. Early and late recovery variables were similar in the two treatment groups; however, 65% N2O produced a 19% decrease in the propofol maintenance dosage requirement. One patient (3%) experienced nausea prior to discharge in the propofol-N2O group, and two patients (6%) experienced nausea at home in the propofol alone group. None of the patients vomited or received antiemetic medication during the 24 hours postdischarge period. Ninety-seven percent of patients receiving propofol alone and all of the patients in the propofol-N2O group were "very satisfied" with their anesthetic experience. CONCLUSIONS: In outpatients undergoing office-based surgical procedures with propofol anesthesia, administration of 65% N2O decreased the anesthetic requirement without increasing PONV. Therefore, use of a propofol-N2O combination may be a cost-effective alternative to propofol alone for office-based anesthesia.

Ambulatory Surgical Procedures↗
PubMed1999

Violence prevention and young adolescents' participation in community youth service.

PURPOSE: To examine whether participation in a school-sponsored community youth service program reduces self-reported violent behaviors among young urban adolescents. METHODS: A total of 972 seventh- and eighth-grade students at two large, urban, public middle schools were surveyed at baseline and at 6-month follow-up. One school was assigned to interventions and the other served as a control. All students at the intervention school received the Reach for Health classroom curriculum that included a 10-lesson unit focusing on violence prevention. In addition, approximately half the students were randomly assigned by classroom to participate in the Reach for Health Community Youth Service program (CYS). Under the guidance of teachers and community nurses, these students spent several hours each week providing service in local health care agencies. Regression analyses were used to assess the influence of treatment condition on violent behavior outcomes. RESULTS: Comparing students in the curriculum-only and curriculum-plus-CYS interventions to the control group, there is a statistically significant interaction (p < .03) among grade, CYS participation, and violence at follow-up. Eighth-grade CYS students reported significantly less violence at follow-up than students in the control school, taking into account baseline level of risk behavior, gender, ethnicity, and social desirability (p < .04). There was no significant difference between controls and students in the curriculum-only condition. Comparing students in the CYS intervention to the curriculum-only condition within the intervention school, the grade by intervention interaction again is significant (p < .05). Eighth-grade CYS students-who received the broadest CYS experience-reported less violence at follow-up than their curriculum-only counterparts. CONCLUSION: When delivered with sufficient intensity, school programs which couple community service with classroom health instruction can have a measurable impact on violent behaviors of a population of young adolescents at high risk for being both the perpetrators and victims of peer violence. Community service programs may be an effective supplement to curricular interventions and a valuable part of multicomponent violence prevention programs.

Adolescent↗
PubMed1999

Allelic variants of human beta-chemokine receptor 5 (CCR5) promoter: evolutionary relationships and predictable associations with HIV-1 disease progression.

Variability in the natural history of HIV-1 infection has been repeatedly associated with genetic variants in the beta-chemokine receptor 5 (CCR5) locus. While CCR5 coding sequences have demonstrated relatively limited variation, sequences of its promoter appear polymorphic in all major populations. Our studies revealed five major CCR5 promoter alleles with distributions that differed widely among the four distinct ethnic groups from Kigali, Rwanda and Bronx, New York. In particular, promoter allele P*0103 (G59029-T59353-T59356-A59402-C59653) was largely restricted to black subjects. The promoter allele P*0202 (A59029-C59353-C59356-A59402-T59653) was tightly linked to the slightly less frequent CCR2b-641, a variant of the CCR2b gene, which is about 12.7 kbp upstream from the promoter region. Another closely related promoter allele P*0201 (A59029-C59353-C59356-A59402-C59653) exclusively carried the far less common CCR5-delta 32, a 32-bp deletion in the CCR5 coding sequence 2 kbp downstream from the promoter. The homozygous P*0201/*0201 genotype can be predicted as a risk factor for more rapid disease progression. Among human, chimpanzee, pig-tailed macaque, and sooty mangabey promoter allelic sequences, the apparent ancestral lineage of the promoter sequence (G59029-T59353-C59356-A59402-C59653 = human P*0102) was highly conserved across the primate species analyzed here while P*0201 and P*0202 arose more recently than the other three major alleles. Further effort to establish the mechanism by which CCR chemokine receptor polymorphisms govern the initiation and pathogenesis of primate lentivirus infection apparently requires fully detailed genotypic characterization of the affected populations.

Alleles↗
PubMed1999

Identification of bloodmeals in haematophagous Diptera by cytochrome B heteroduplex analysis.

We developed a DNA assay for bloodmeal identification in haematophagous insects. Specific host cytochrome B gene sequences were amplified by PCR and classified on the basis of their mobility in a heteroduplex assay. In the blackfly Simulium damnosum s.l. (Diptera: Simuliidae), human cytochrome B DNA sequences were identifiable up to 3 days following ingestion of the bloodmeal. In the tsetse Glossina palpalis (Diptera: Glossinidae) collected from tsetse traps in Ivory Coast, bloodmeals were identified as taken from domestic pigs on the basis of their heteroduplex pattern and DNA sequence. Evidently the cytochrome B sequence shows sufficient interspecific variation to distinguish between mammalian host samples, while exhibiting minimal intraspecific variation. The stability of DNA in bloodmeals, for several days post-ingestion by haematophagous insects, allows PCR-HDA assays to be used reliably for host identification.

Animals↗
PubMed1999

Consistent associations of HLA class I and II and transporter gene products with progression of human immunodeficiency virus type 1 infection in homosexual men.

Polymorphic products of genes in the HLA region contributing to variability in the course of human immunodeficiency virus type 1 (HIV-1) infection were identified by screening 375 Caucasian seroconverters who were aggregated from 3 cohorts. AIDS-free time was related to numerous (15) class I alleles, alone or in conjunction with transporter protein variants, to homozygosity at the A or B locus, and to alleles of two class II haplotypes. A prognostic scoring algorithm derived from the 3 cohorts captured multiple HLA contributions to protection or to risk (relative hazard=0.57-60 per unit increase in score, all P<<.001). The impact of HLA was strong and appeared independent of the effects of chemokine receptor/ligand polymorphisms and antiretroviral treatment. The algorithm also predicted divergent rates of CD4+ cell decline in 2 other groups, totaling 227 seropositive persons (P=.06 - <.001). Confirmation of these relationships should encourage investigation of HIV-1 antigen processing and presentation mediated by polymorphisms in the HLA region.

Adult↗
PubMed1999

Changes in rat brain cholinesterase activity and muscarinic receptor density during and after repeated oral exposure to chlorpyrifos in early postnatal development.

The effects of repeated oral exposures to the organophosphorus insecticide chlorpyrifos (CPS) on brain muscarinic receptor densities, together with cholinesterase (ChE) activity, were studied in early postnatal rats. Initially, the effects on esterases from lactational exposure to CPS were investigated in young rats by administering CPS (100, 150, or 200 mg/kg subcutaneously in corn oil) to dams 1 day postpartum, yielding a significant body burden of CPS in the dams for possible excretion in the milk. Brain ChE inhibition in pups was less severe than in dams, whereas liver carboxylesterase (CbxE) inhibition in pups was at the same level as in dams. Because of the limited brain ChE inhibition obtained following lactation, pups were exposed to CPS directly by gavage, using 3 dosing regimens to yield a dose response. The rats were gavaged with CPS in corn oil on alternate days from postnatal day (PND) 1 through PND 21. Rats in the low-dosage group received 11 treatments at 3 mg/kg, those in the medium-dosage group received 3 treatments at 3 mg/kg and 8 at 6 mg/kg, and those in the high dosage group received 3 treatments at 3 mg/kg, 4 at 6 mg/kg, and 4 at 12 mg/kg. ChE activity in brain homogenates were inhibited significantly by 29% and 63% in the low- and high-dosage groups, respectively, on PND 22 and by 17% in the high dosage group on PND 40. Muscarinic receptor densities in brain synaptosomes were reduced using 3H-N-methylscopolamine (NMS) and 3H-quinuclidinyl benzilate (QNB) as ligands, with the effects more prominent from 3H-NMS. Densities of both ligands recovered to the control level several days after terminating treatment. The results indicate that pups are apparently exposed to only limited amounts of chlorpyrifos and/or its oxon through the milk when dams are exposed to extremely high chlorpyrifos levels. In addition, repeated direct oral exposures of early postnatal rats to CPS will result in persistent brain ChE inhibition and will transiently reduce muscarinic receptor density.

Administration, Oral↗
PubMed1999

Comparison of the sedation and recovery profiles of Ro 48-6791, a new benzodiazepine, and midazolam in combination with meperidine for outpatient endoscopic procedures.

UNLABELLED: In this randomized, double-blinded study, we compared the onset and recovery characteristics of an investigational benzodiazepine, Ro 48-6791 (when administered alone or combined with meperidine), a midazolam-meperidine combination for sedation during gastrointestinal (GI) endoscopic procedures. Ninety consenting outpatients scheduled for upper or lower GI procedures were randomly assigned as follows: Group I received midazolam 1 mg IV and meperidine 50 mg; Group II received Ro 48-6791 0.5 mg IV and meperidine 50 mg; or Group III received Ro 48-6791 1.0 mg IV alone. If the level of sedation did not achieve an Observer's Assessment of Alertness/Sedation (OAA/S) score of 4 (where 5 = awake/alert to 1 = asleep) in < or = 2 min, a second bolus dose, equal to half of the original dose of midazolam or Ro 48-6791, was administered. The onset time was defined as the time to achieve an OAA/S score of 4. During the procedure, a bolus dose equal to half of the total induction dose was given to maintain an OAA/S score of 4. The induction and maintenance dosages, as well as recovery times to an OAA/S score of 5, were recorded. A heel-toe line walk (HTLW) test used to determine the time to "fitness for discharge." Although the onset times were similar in all three groups, the induction dosages were significantly reduced in Group II compared with Groups I and III. There were significantly more patients requiring supplemental sedative boluses and "rescue" analgesia with Ro 48-6791 than with midazolam. The Ro 48-6791 groups also experienced more dizziness after the procedures. Ro 48-6791 was associated with a higher incidence of inadequate sedation (18% vs 3%) without the opioid. The time for the HTLW test to return to baseline values after the procedure was similar among the three groups. However, the Ro 48-6791 groups had significantly reduced times to return to an OAA/S score of 5 and to achieve the baseline HTLW value after the last dose of the benzodiazepine. In conclusion, compared with midazolam, Ro 48-6791 is more potent and may be associated with a more rapid early recovery after endoscopic GI procedures. However, sedation with Ro 48-6791 required more supplemental bolus doses and "rescue" analgesic medication and was associated with a higher incidence of dizziness. IMPLICATIONS: The investigational water-soluble benzodiazepine, Ro 48-6791, is a more potent sedative than midazolam, which appears to have a slightly shorter duration of action. Unfortunately, use of Ro 48-6791 increased the requirement for supplemental doses of the sedative medication and the need for "rescue" analgesics during the procedure and was associated with more dizziness after the procedure.

Adjuvants, Anesthesia↗
PubMed1999

Recovery profile, costs, and patient satisfaction with propofol and sevoflurane for fast-track office-based anesthesia.

BACKGROUND: Office-based surgery is becoming increasingly popular because of its cost-saving potential Both propofol and sevoflurane are commonly used in the ambulatory setting because of their favorable recovery profiles. This clinical investigation was designed to compare the clinical effects, recovery characteristics, and cost-effectiveness of propofol and sevoflurane when used alone or in combination for office-based anesthesia. METHODS: One hundred four outpatients undergoing superficial surgical procedures at an office-based surgical center were randomly assigned to one of three general anesthetic groups. In groups I and II, propofol 2 mg/kg was administered for induction followed by propofol 75-150 microg x kg(-1) x min(-1) (group I) or sevoflurane 1-2% (group II) with N2O 67% in oxygen for maintenance of anesthesia In group m, anesthesia was induced and maintained with sevoflurane in combination with N2O 67% in oxygen. Local anesthetics were injected at the incision site before skin incision and during the surgical procedure. The recovery profiles, costs of drugs, and resources used, as well as patient satisfaction, were compared among the three treatment groups. RESULTS: Although early recovery variables (e.g., eye opening, response to commands, and sitting up) were similar in all three groups, the times to standing up and to be "home ready" were significantly prolonged when sevoflurane-N2O was used for both induction and maintenance of anesthesia. The time to tolerating fluids, recovery room stay, and discharge times were significantly decreased when propofol was used for both induction and maintenance of anesthesia. Similarly, the incidence of postoperative nausea and vomiting and the need for rescue antiemetics were also significantly reduced after propofol anesthesia. Finally, the total costs and patient satisfaction were more favorable when propofol was used for induction and maintenance of office-based anesthesia CONCLUSION: Compared with sevoflurane-N2O, use of propofol-N2O for office-based anesthesia was associated with an improved recovery profile, greater patient satisfaction, and lower costs. There were significantly more patients who were dissatisfied with the sevoflurane anesthetic technique.

Adult↗
PubMed1999

Area x-ray beam equalization for digital angiography.

An area beam equalization technique has been investigated in order to generate patient-specific compensating filters for digital angiography. An initial image was used to generate the compensating filter, which was fabricated using a deformable compensating material, containing CeO2, and an array of square pistons. The CeO2 attenuator thicknesses were calculated using the gray level information from the initial unequalized image. The array of pistons was pressed against a uniform thickness of attenuating material to generate a filter for x-ray beam equalization. The filter was subsequently inserted into the x-ray beam for the final equalized radiograph. It was positioned close to the focal spot (magnification of 8.0) in order to minimize edge artifacts from the filter. The equalization of x-ray transmission across the field exiting from the object significantly improved the image quality by preserving local contrast throughout the image. The contrast-to-noise ratio (CNR) in the equalized images was increased-by up to fivefold. Phantom studies indicate that equalized images using a relatively small array of pistons (e.g., 8 x 8) produce significant improvement in image quality with negligible perceptible artifacts. Animal studies showed that beam equalization significantly improved fluoroscopic and angiographic image quality. X-ray beam equalization produced an image with a relatively uniform scatter-glare intensity and it reduced the scatter-glare fraction in the previously underpenetrated region of the image from 0.65 to 0.50. Also, x-ray tube loading due to the mask assembly itself was negligible. In conclusion, area beam equalization reduces the scatter-glare fraction and significantly improves CNR in the previously underpenetrated region of the image.

Angiography, Digital Subtraction↗
PubMed1999

Gene disruption studies of penicillin-binding proteins 1a, 1b, and 2a in Streptococcus pneumoniae.

The effects of inactivation of the genes encoding penicillin-binding protein 1a (PBP1a), PBP1b, and PBP2a in Streptococcus pneumoniae were examined. Insertional mutants did not exhibit detectable changes in growth rate or morphology, although a pbp1a pbp1b double-disruption mutant grew more slowly than its parent did. Attempts to generate a pbp1a pbp2a double-disruption mutant failed. The pbp2a mutants, but not the other mutants, were more sensitive to moenomycin, a transglycosylase inhibitor. These observations suggest that individually the pbp1a, pbp1b, and pbp2a genes are dispensable but that either pbp1a or pbp2a is required for growth in vitro. These results also suggest that PBP2a is a functional transglycosylase in S. pneumoniae.

Bacterial Proteins↗
PubMed1999

Characterization of unique truncated prolactin receptor transcripts, corresponding to the intracellular domain, in the testis of the sexually mature chicken.

We have examined expression of the chicken PRL receptor (cPRLR) gene in different tissues of the chicken by Northern blot analysis. Most tissues examined (ovary, testis, oviduct, kidney, and fat) possess a prominent full-length (4.6-kb) cPRLR transcript. A larger (11.7-kb) transcript is also detected in ovary, oviduct, testis, and kidney after longer exposure. A unique pattern of cPRLR expression was found in the testis of sexually mature chickens, which have an unusually high abundance of three small transcripts (1.2, 1.7, and 2 kb) in addition to the 4.6-kb transcript found in other tissues. Three domain-specific complementary DNA (cDNA) probes were constructed that correspond to the first and second ligand-binding regions in the extracellular domain and the transmembrane-intracellular domain. With these probes, Northern blot analysis of polyadenylated RNA prepared from the testes of a mature (22-week-old) chicken indicates that the highly abundant (1.2- and 1.7-kb) and less abundant (2.0-kb) cPRLR transcripts in testis hybridize only to the intracellular domain probe. Two types of truncated testis-specific cPRLR transcripts were identified using 5'-RACE (rapid amplification of cDNA ends) analysis of polyadenylated RNA from the testis of a 22-week-old chicken. The predominant truncated cDNA sequence contains the highly conserved box 1 motif [(+)box 1 cDNA] and diverges (at nucleotide 1396) from that of the cPRLR cDNA, just downstream of the transmembrane domain. The other truncated cDNA lacks the box 1 motif [(-)box 1 cDNA], which is replaced by 39 bases that could encode a hydrophobic N-terminus with a putative 5'-untranslated region of 131 bases. Young chickens predominately express the full-length cPRLR messenger RNA (4.6 kb) in the testis. At the onset of sexual maturity, there is a dramatic increase in abundance of the testis-specific (+)box 1 transcript, whereas expression of the full-length cPRLR is depressed. The presence of truncated [(+) or (-)box 1] cPRLR transcripts in the sexually mature chicken testis suggests a complex mechanism of PRL action on gonadal function.

Amino Acid Sequence↗
PubMed1999

The effectiveness of the Reach for Health Community Youth Service learning program in reducing early and unprotected sex among urban middle school students.

OBJECTIVES: This study evaluated the effectiveness of a community youth service (CYS) program in reducing sexual risk behaviors among African American and Latino urban young adolescents. METHODS: A total of 1061 students at 2 urban middle schools were surveyed at baseline and 6-month follow-up. Students at one school were randomly assigned by classroom to receive either the Reach for Health CYS program or the Reach for Health classroom curriculum only. Students at the other school served as controls. RESULTS: At follow-up. CYS participants reported significantly less recent sexual activity (P < .05) and scored lower on a sexual activity index than those in the control condition (P < .03). The greatest effect was among eighth graders, who received the most intensive service program (P < .03). The benefit of the curriculum-only intervention appeared greatest among students in special education classes. CONCLUSIONS: Well-organized CYS that couples community involvement with classroom health instruction can have a positive impact on the sexual behaviors of young adolescents at risk for HIV, sexually transmitted diseases, and unintended pregnancy. This study also suggests the importance of including students in special education classes in health education programs.

Adolescent↗
PubMed1999

Community learning: the Reach for Health Nursing Program-Middle School Collaboration.

Nursing faculty and students have a vital role to play in promoting adolescent health at the community level. However, few nursing education programs have developed programs which provide nursing students with the skills and hands-on experiences they need to work with adolescents in community settings. A successful model for integrating community-based adolescent health promotion into nursing education is described in this article. Developed by nursing faculty from Medgar Evers College Department of Nursing, teachers and staff from a large middle school in Brooklyn, New York serving economically disadvantaged Black and Hispanic youth, and Education Development Center, Inc., the Reach for Health (RFH) Nursing Program-Middle School Collaboration has two mutually reinforcing components: (a) classroom-based health instruction taught by teachers with assistance from nursing students and faculty, and (b) community youth service in which middle school students spend approximately 3 hours per week providing assistance in health-related facilities under the guidance of nursing faculty and student nurse mentors. As part of an evaluation study, the authors conducted focus groups with nursing students involved in this program and administered an identical survey before and after intervention to assess potential benefits of participation. Compared to a control group of nursing students, those who participated in the RFH program reported increased skills and comfort working in school and community settings and with young adolescents, their teachers, and their parents. An example of other benefits was a greater understanding of the health and developmental needs of adolescents. At the same time they provided a service to the community, nursing students gained the skills and experience needed to be effective in community health promotion efforts.

Adolescent↗
PubMed1999

[Computerized ribosomal RNA secondary structure modeling of mutants found in Rett syndrome patients and their mothers].

OBJECTIVE: To identify the secondary structure of rRNA mutants, mtDNA2835(C-->T) and mtDNA2706(A-->G) found in Rett syndrome patients and their mothers. METHODS: Both wild type mtDNA sequence of rRNA gene and mutated sequence were input into computer (converted into RNA sequences) and analyzed by the sofware DNASIS v6. 14. The unique prediction size is set 300 bases and the maximum bulge and interior loop size,30 bases. RESULTS: Similar to the positive controls, the mtDNA2835(C-->T) made the 16S rRNA secondary structure totally different,and the energy changes a lot. On the contrary, the mtDNA2706(A-->G) altered little of secondary structure with a small energy shift. CONCLUSION: Computerized folding programs have provided us with a quick prediction of rRNA structure changes induced by these two mutations. Of them, the mtDNA2835(C-->T) might relate to the pathogenesis of Rett syndrome, but the mtDNA2706(A--> G) might be less meaningful.

Computer Simulation↗
PubMed1999

Waianae Diet Program: long-term follow-up.

A long-term follow-up was conducted on 82 participants from prior programs based on ad libitum feeding of a traditional Hawaiian diet. Follow-up period ranged from 12 months to 90 months and averaged 33.67 months. An average weight loss of 15.1 pounds was maintained over 7.5 years of follow-up (p < 0.0005) even when stratified over two year intervals, suggesting that this type of program may be an effective long-term weight loss intervention.

Adult↗