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Biomedical subjects

T Hall

Publications and source records attributed to T Hall.

At least 55 records · Page 3Linked to original sources
PubMed1997

Percutaneous nephrostomy: placement under CT and fluoroscopy guidance.

OBJECTIVE: The purpose of this paper is to present our experience with CT- and fluoroscopy-guided percutaneous nephrostomy tube (PNT) placement and to describe the technique of placement with patients in the supine-oblique position. MATERIALS AND METHODS: A CT scanner was coupled with a ceiling-mounted C-arm for fluoroscopy at the CT table, PNT was done with CT localization and fluoroscopic control. We attempted 148 placements in 129 patients, with most patients in the supine or the supine-oblique position. RESULTS: Successful PNT placement was achieved in 144 (97%) of 148 kidneys. In the native kidney group, 101 (81%) of 124 PNTs were placed with the patients in the supine-oblique position. We experienced no major complications, three (2%) minor complications, and two (1%) catheter dislodgments. CONCLUSION: CT-fluoroscopy control allows routine PNT placement with patients in the supine or the supine-oblique position and is associated with the lowest complication rate to our knowledge.

Adolescent↗
PubMed1997

Anterior approach to the cervicothoracic junction: an anatomic dissection.

The anterior surgical approach to the cervicothoracic spine presents a challenge to the spine surgeon. To adequately explore the anterior spine from C4 to T4 requires a midsternotomy with extended anterior cervical incision. This approach most adequately provides the extensive cranial-caudal exposure required in dealing with tumors at the cervicothoracic junction. Our surgical experience with five patients harboring tumors in this area of the spine has led us to reflect on the anatomy of the exposure and the corridors of approach at various levels of the cervicothoracic junction. Cadaver dissection and demonstration of the anatomic structures encountered in this exposure and the spinal subdivisions created by these various neurovascular structures will be presented. The anatomy, so demonstrated, will be correlated with the clinical cases.

Anatomy, Artistic↗
PubMed1996

A solid-phase assay for the determination of protein tyrosine kinase activity of c-src using scintillating microtitration plates.

A solid-phase assay for the determination of protein tyrosine kinase (PTK) activity has been developed. The transfer of 33PO4 from ATP to the synthetic substrate poly(Glu, Tyr) 4:1 attached to the bioactive surface of scintillating microtiter plates served as the basis to evaluate enzyme activity. The procedure eliminates detection with phosphotyrosine antibodies, tedious separation of phosphorylated peptides with phosphocellulose membranes, and extensive washing steps. For these reasons, the traditionally time-consuming procedure can be performed with a simple three-step protocol. The method is highly accurate, rapid, and robotics friendly. The advantages over existing assays make this procedure especially suited for high throughput applications.

Animals↗
PubMed1996

Safety, immunogenicity, and efficacy of Plasmodium falciparum repeatless circumsporozoite protein vaccine encapsulated in liposomes.

Seventeen malaria-naive volunteers received a recombinant Plasmodium falciparum vaccine (RLF) containing the carboxy- and the amino-terminal of the circumsporozoite protein (CSP) antigen without the central tetrapeptide repeats. The vaccine was formulated in liposomes with either a low or high dose of 3-deacylated monophosphoryl lipid A (MPL) and administered with alum by intramuscular injection. Both formulations were well tolerated and immunogenic. MPL increased sporozoite antibody titers measured by ELISA, Western blot, and immunofluorescence assay. One high-dose MPL vaccine formulation recipient developed a CSP-specific cytotoxic T lymphocyte response. After homologous sporozoite challenge, immunized volunteers developed patent malaria. There was no correlation between prepatent period and antibody titers to the amino- or carboxy-terminal. The absence of delay in patency argues against inclusion of the amino-terminal in future vaccines. A significant cytotoxic T lymphocyte response may have been suppressed by the inclusion of alum as an adjuvant.

Adolescent↗
PubMed1996

Immunization of Aotus nancymai with recombinant C terminus of Plasmodium falciparum merozoite surface protein 1 in liposomes and alum adjuvant does not induce protection against a challenge infection.

Merozoite surface protein 1 (MSP-1) of Plasmodium falciparum is an antimalarial vaccine candidate. The highly conserved 19-kDa C-terminal processing fragment of MSP-1 (MSP-1(19)) is of particular interest since it contains epitopes recognized by monoclonal antibodies which inhibit the invasion of erythrocytes in vitro. The presence of naturally acquired anti-MSP-1(19) antibodies in individuals exposed to malaria has been correlated with reduced morbidity, and immunization with an equivalent recombinant P. yoelii antigen induces substantial protection against this parasite in mice. We have expressed P. falciparum MSP-1(19) in Escherichia coli as a correctly folded protein and immunized Aotus nancymai monkeys by using the protein incorporated into liposomes and adsorbed to alum. After vaccination, the sera from these animals contained anti-MSP-1(19) antibodies, some of which competed for binding to MSP-1(19) with monoclonal antibodies that inhibit parasite invasion of erythrocytes in vitro. However, after challenge with either a homologous or a heterologous strain of parasite, all animals became parasitemic and required treatment. The immunization did not induce protection in this animal model.

Adjuvants, Immunologic↗
PubMed1995

Comparison of sampling anopheline mosquitoes by light-trap and human-bait collections indoors at Bagamoyo, Tanzania.

The mosquito sampling efficiency of CDC miniature light-traps, relative to night-biting collections, was evaluated indoors at two sites in coastal Tanzania. We found that the total number of anophelines captured overnight by light-traps (hung beside a bednet in use) was 1.23 times the number of anophelines captured by human-bait collections. This relationship was not affected significantly by changes in the mosquito density, order of trapping method, date of sampling, or number of household occupants. Malaria sporozoite rates were twice as high among mosquitoes captured by light-trap as compared to those captured by night-biting collection. This was attributed to the tendency of light-traps to capture a larger proportion of gravid mosquitoes, which also had high sporozoite rates. The differences in sporozoites rates according to abdominal stage indicates that unfed mosquitoes captured by light-traps may define more precisely the human-biting activity and sporozoite rates as seen by night-biting collections. Our study shows that light-traps, when used in combination with night-biting collections, can be an effective and sensitive means for measuring human-biting activity and the sporozoite rate.

Animals↗
PubMed1995

Malaria infection potential of anopheline mosquitoes sampled by light trapping indoors in coastal Tanzanian villages.

Anopheline mosquito populations were studied during 1992 in seven villages south of Bagamoyo, coastal Tanzania, prior to malaria control intervention using insecticide treated bednets. To collect mosquitoes, CDC light traps were used in ten houses per village fortnightly for 12 months. Anopheles females were identified and checked by ELISA for the presence of malaria sporozoite antigen and source of bloodmeal. An.funestus peaked in June-July after the long rains. Three members of the An.gambiae complex had different seasonality: An.arabiensis, An.gambiae and small numbers of An.merus were collected. In most villages transmission was extremely high and perennial with the entomological inoculation rate reaching three to eleven infective bites per person per night in July and persisting at around 0.1 and 1 for most of the remainder of the year. Sporozoite infection rates within the An.gambiae complex ranged from 2% to 25%, with the peaks in January and July following the two rainy periods. An.funestus showed a similar pattern. The light traps were reliable, simple to operate, and proved to be satisfactory to study the mosquito vector population.

Animals↗
PubMed1994

Azithromycin prophylaxis against a chloroquine-resistant strain of Plasmodium falciparum.

Azithromycin has antimalarial activity and favourable pharmacokinetic properties for a prophylactic antimalarial agent. We investigated the ability of azithromycin to prevent malaria in volunteers infected with a chloroquine-resistant strain of Plasmodium falciparum. 4 volunteers received oral azithromycin 500 mg followed by 250 mg daily for 7 further days. Subjects were infected on the third day of azithromycin. 3 subjects were protected compared with none of 15 controls. The volunteer not protected by azithromycin had unquantifiable plasma levels of azithromycin, probably because of poor absorption. Azithromycin could be a promising prophylactic agent for P falciparum malaria.

Administration, Oral↗
PubMed1994

A strand bias occurs in point mutations associated with variant surface glycoprotein gene conversion in Trypanosoma rhodesiense.

We previously described a bloodstream Trypansoma rhodesiense clone, MVAT5-Rx2, whose isolation was based on its cross-reactivity with a monoclonal antibody (MAb) directed against a metacyclic variant surface glycoprotein (VSG). When the duplicated, expressed VSG gene in MVAT5-Rx2 was compared with its donor (basic copy) gene, 11 nucleotide differences were found in the respective 1.5-kb coding regions (Y. Lu, T. Hall, L. S. Gay, and J. E. Donelson, Cell 72:397-406, 1993). Here we describe a characterization of two additional bloodstream trypanosome clones, MVAT5-Rx1 and MVAT5-Rx3, whose VSGs are expressed from duplicated copies of the same donor VSG gene. The three trypanosome clones each react with the MVAT5-specific MAb, but they have different cross-reactivities with a panel of other MAbs, suggesting that their surface epitopes are similar but nonidentical. Each of the three gene duplication events occurs at a different 5' crossover site within a 76-bp repeat and is associated with a different set of point mutations. The 35, 11, and 28 point mutations in the duplicated VSG coding regions of Rx1, Rx2, and Rx3, respectively, exhibit a strand bias. In the sense strand, of the 74 total mutations generated in the three duplications, 54% are A-to-G or G-to-A (A:G) transitions and 7% are C:T transitions, while 26% are C:A transversions and 13% are C:G transversions. No T:G or T:A transversions occurred. Possible models for the generation of these point mutations are discussed.

Amino Acid Sequence↗
PubMed1994

A monocistronic transcript for a trypanosome variant surface glycoprotein.

Many protein-encoding genes of African trypanosomes are transcribed as large polycistronic pre-mRNAs that are processed into individual mRNAs containing a 5' spliced leader and 3' poly(A). The 45- to 60-kb pre-mRNAs encoding some variant surface glycoproteins (VSGs) contain as many as eight unrelated coding regions. Here we identify the promoter for a metacyclic VSG gene that is expressed without duplication in a bloodstream trypanosome clone. This 70-bp promoter is located 2 kb upstream of the telomere-linked VSG gene and directs the synthesis of a monocistronic VSG pre-mRNA lacking the 5' spliced leader. Its sequence only slightly resembles those of other known trypanosome promoters, but it does cross-hybridize with several related sequences elsewhere in the genome. These results suggest that a new class of trypanosome promoters has been found, whose function is to initiate monocistronic transcription of those VSG genes normally expressed during the metacyclic stage.

Amino Acid Sequence↗
PubMed1994

Making love: Australian adults' rating of its importance as a romantic act in a relationship.

A personal opinion survey was administered to 1207 adults assessing attitudes towards 13 romantic acts with regard to age and gender. The present study focused upon attitudes towards the perceived importance of making love as a romantic act in a relationship. The sample was divided into three age groups, 18 to 25 years, 26 to 35 years, and 36 to 45 years. Analysis showed that 600 men's mean rating on a 5-point scale for importance was higher than the 607 women's rating; however, no significant difference was found among age groups and the interaction of age and gender was nonsignificant.

Adolescent↗