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Biomedical subjects

L Jackson

Publications and source records attributed to L Jackson.

At least 55 records · Page 3Linked to original sources
PubMed1996

Theileria annulata: altered gene expression and clonal selection during continuous in vitro culture.

Kept in continuous in vitro culture, the protozoan parasite Theileria annulata gradually loses virulence when inoculated into cattle. These attenuated cell lines form the basis of the in vitro live vaccines which have been used successfully to control tropical theileriosis in several endemic regions. In the study reported here, events occurring during in vitro culture of an Indian (Hisar) cell line, which may be associated with the reduction in virulence, have been investigated. Hybridization with two polymorphic DNA probes following Southern blotting showed that selection of particular parasite genotypes occurs very rapidly with culture; a novel hybridization pattern is observed with both probes after 50-100 passages in vitro. In addition to this selection process, immunofluorescence studies using a monoclonal antibody which specifically recognizes virulent T. annulata revealed alterations in antibody reactivity following in vitro culture. This loss of reactivity was observed in three cloned cell lines derived from the early, virulent Hisar line and implies that phenotypic changes resulting from alterations to parasite gene expression are taking place during the attenuation process. When considered with the results from in vivo infections with serial passages of this cell line, it can be proposed that both altered gene expression and selection may be involved in the loss of pathogenicity of T. annulata during continuous in vitro culture.

Animals↗
PubMed1996

Chorionic villus sampling safety. Report of World Health Organization/EURO meeting in association with the Seventh International Conference on Early Prenatal Diagnosis of Genetic Diseases, Tel-Aviv, Israel, May 21, 1994.

Accumulated experience of 138,996 cases of chorionic villus sampling shows that chorionic villus sampling is a safe procedure with an associated fetal loss rate comparable to that of amniocentesis. The chorionic villus sampling registry shows that chorionic villus sampling is currently performed primarily between 9 and 12 weeks' gestation and carried no increased risk of limb reduction defects: the overall incidence of limb reduction defects after chorionic villus sampling is 5.2 to 5.7 per 10,000, compared with 4.8 to 5.97 per 10,000 in the general population. Analysis of the pattern distribution of limb defects after chorionic villus sampling revealed no difference from the pattern in the general population. This applies specifically to transverse limb defects. Together with the overall incidence of limb reduction defects, these data provide no evidence for any risk for congenital malformation determined by chorionic villus sampling. Because chorionic villus sampling is currently performed generally after 8 completed weeks of pregnancy, few data are available for analysis of complications related to earlier procedures. Avoiding early chorionic villus sampling also excludes sampling in cases of early fetal death, which can be diagnosed reliably by ultrasonography at 9 weeks of pregnancy.

Chorionic Villi Sampling↗
PubMed1996

A rare variant of mirror hand: a case report.

Mirror hand is one of the rarest congenital differences of the upper extremity. Typically, there is absence of the radius, duplication of the ulna, and 7 digits in mirrored symmetry about the middle finger. We report a case of a rarer subset of hand duplication in which there is a normal radius and ulna and a hand with 8 digits. The patient underwent surgery to excise the radial 3 digits and to reconstruct the remaining radial digit to function as an opposable, 2 phalanx thumb. Wrist extension was augmented by transferring the digital extensors from the excised fingers to the radial wrist extensors.

Hand Deformities↗
PubMed1996

Diagnosis of a complex chromosomal rearrangement using fluorescent in situ hybridisation.

We report the use of fluorescent in situ hybridisation (FISH) to clarify a complex chromosomal rearrangement (CCR) carried by a woman presenting with recurrent miscarriages. CCRs are rare cytogenetic rearrangements involving three or more chromosomes, which can be difficult to interpret using routine cytogenetic studies with GTG banding. FISH was used to establish a correct interpretation of the maternal karyotype before amniocentesis in a present pregnancy.

Abortion, Habitual↗
PubMed1996

A randomized, placebo-controlled trial of combined insulin-like growth factor I and low dose growth hormone therapy for wasting associated with human immunodeficiency virus infection.

Loss of body mass, or wasting, is a major cause of morbidity and a contributor to mortality in human immunodeficiency virus-1 (HIV-1) infection. Dietary supplements and appetite adjuvants have had limited effectiveness in treating this condition. GH and insulin-like growth factor I (IGF-I) have been shown to be anabolic in many catabolic conditions, and limited data suggest similar efficacy in HIV wasting. In addition, it appears that GH and IGF-I may have complementary anabolic effects with opposing glucoregulatory effects. We report results from a 12-week randomized, placebo-controlled trial of combination recombinant human GH (rhGH; Nutropin; 0.34 mg, sc, twice daily) and rhIGF-I (5.0 mg, sc, twice daily) in individuals with HIV wasting and without active opportunistic infection, cancer, or gastrointestinal disease. A total of 142 subjects (140 males and 2 females) were randomized using a 2:1, double blind treatment scheme and assigned to receive either active treatment or placebo injections. Eighty subjects completed the 12-week protocol. Nutritional intake and demographic and clinical characteristics did not differ between the groups at any study time point. At 3 weeks, the treatment group had a significantly larger weight increase (P = 0.0003), but this difference was not observed at any later time point. Similarly, fat-free mass, calculated from skinfold measurements, increased transiently in the treatment group at 6 weeks (P = 0.002). No significant differences in isokinetic muscle strength or endurance testing or in quality of life were observed between the groups. Resting heart rate was significantly higher in the treatment group at each time point post-baseline. GH and IGF-binding protein-3 levels did not change; however, IGF-I levels were higher in the treatment group at 6 and 12 weeks. There were no significant between-group differences in any of the measured biochemical or immunological parameters. rhGH plus rhIGF-I treatment was associated with an increased incidence of peripheral edema and other side-effects, possibly related to fluid retention. We conclude that the combination of rhIGF-I and low dose rhGH used in this study had no significant anabolic effect in HIV wasting.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Family therapy skills for general practitioners.

General practitioners are often the first health professionals that families turn to for help at times of stress. Figures from around the world suggest that up to 80% of general practice consultations have psychological or stress based issues as a significant aspect of the presenting problems. In this paper the place of patients in a wider context is emphasised and skills with which the GP can respond to the patient and his or her family are discussed. The value of listening to patients for both the content and the feelings without necessarily trying to solve the presenting problems is emphasised.

Adult↗
PubMed1995

Structurally defined synthetic cancer vaccines: analysis of structure, glycosylation and recognition of cancer associated mucin, MUC-1 derived peptides.

Translation of an immune response into therapy is probably the toughest task in designing vaccines for cancer due to the heterogeneity of the cell surface antigens which display tremendous variations in glycoforms. Consequently, a small segment (antigen) of cancer-associated mucin, in spite of generating antigen-specific immune responses, may be limited in therapeutic value. It is important that the synthetic segment resembles the native cancer-associated mucin in both structure and conformation. Synthetic cancer associated mucin derived 16 amino acid peptide GVTSAPDTRPAPGSTA and its partially glycosylated forms have demonstrated specific binding to two monoclonal antibodies, B27.29 and BCP8, raised against the native cancer associated mucin, MUC-1 and a MUC-1 derived synthetic peptide, respectively. In spite of the structural similarities at the core peptide level of both glycosylated and unglycosylated peptides, it appears that partial glycosylation does not inhibit and even slightly enhances binding to the MAb B27.29 indicating that the glycosylated synthetic peptide more closely resembles the native mucin epitope recognized by MAb B27.29. From molecular dynamic simulations using NMR derived distance constraints, both glycosylated and unglycosylated peptides have shown a type 1 beta turn involving the same amino acids in both glycosylated and unglycosylated peptides. The alpha GalNAc attached to the threonine (T3) and serine (S4) in the 16 amino acid sequence has not imposed any conformational changes to the peptide backbone nor has offered severe steric resistance to the binding of either antibody to the glycopeptides as indicated by hapten inhibition studies. Nevertheless, all peptides have displayed glycosylation dependent specificities in binding to these antibodies, i.e. the glycosylated peptides demonstrated relative higher affinities to the native mucin antibody B27.29 while the unglycosylated peptide is more specific to the MAb BCP8. Immune responses generated by these synthetic glycopeptides are highly specific in recognizing the native cancer associated mucin.

Acetylgalactosamine↗
PubMed1995

Effect of maternal rotavirus immunization on milk and serum antibody titers.

This prospective study evaluated human milk and serum antirotavirus antibody concentrations following maternal rotavirus immunization. Postpartum women (33) were randomized into 3 groups and received a single oral dose of rhesus rotavirus monovalent reassortant vaccine (10(4) pfu), tetravalent vaccine (10(4) pfu), or placebo. Milk (secretory [s] IgA) and serum (IgA and IgG) specimens were tested for antirotavirus isotype-specific antibody. Sera also were tested for G1- to G4-specific antibody. Prevaccine milk and serum isotype-specific antibody concentrations were not significantly different in the 3 groups. Postvaccine sIgA log titers were significantly greater in the 2 vaccine groups than the placebo group (P = .002). Mean log10 titers at 1 week were 2.1 (95% confidence interval [CI], 2.0-2.3) in the 2 vaccine groups and 1.7 (95% CI, 1.5-1.9) in the placebo group. Milk titers did not differ between vaccine groups. There was no difference in reactogenicity between groups. The significantly higher milk concentrations of antibody to rotavirus in postpartum women who received rotavirus immunization persisted for 4 months.

Adolescent↗
PubMed1995

Strike-through contamination in saturated sterile dressings: a clinical analysis.

This multisite study examined the risk of strike-through contamination of 4" x 4" gauze sponges using a shortcut method of saturating sterile sponges directly on their wrappers. Sterile gauze sponges were saturated directly on their wrappers on hospital over-bed tables of postoperative general surgical patients. Cultures were taken at 0.5, 1, 3, and 5 minutes after saturation to ascertain whether strike-through contamination occurred. Saturated sponges showed significant microorganism growth when compared to expected zero microorganisms at all sampling times following saturation. Although microorganisms identified in strike-through contamination were not microbiologically or pathogenically threatening, the basic principle of asepsis was violated. There was no significant difference in strike-through contamination between sponges saturated on coated wrappers and sponges saturated on uncoated wrappers. Clinicians should be aware that coated wrappers do not provide a moisture-proof barrier against strike-through contamination. The findings suggest the shortcut method should not be used for saturating sponges.

Asepsis↗
PubMed1994

Protecting the gut and the liver in the critically ill: effects of dopexamine.

OBJECTIVE: To measure the clinical effects of dopexamine on systemic and splanchnic perfusion in critically ill patients. DESIGN: Prospective study. SETTING: General intensive care unit. PATIENTS: Ten patients with sepsis syndrome, acute respiratory failure, and at least one other organ system in failure. The median age of the patients was 62.5 yrs (range 29 to 78), and the median admission Acute Physiology and Chronic Health Evaluation (APACHE) II score was 24 points (range 14 to 38). INTERVENTIONS: Timed infusion of dopexamine to a maximum dose of 6 micrograms/kg/min. MEASUREMENTS AND MAIN RESULTS: Systemic hemodynamics and oxygen transport variables were obtained from measurements after arterial and pulmonary artery catheterization. Gastric intramucosal pH and hepatic blood flow/function measurements were made by tonometry and indocyanine green clearance, respectively. All measurements were made before dopexamine infusion, after 1 hr of dopexamine infusion, and again 1 hr after the infusion ended. Cardiac index increased with dopexamine from a baseline median of 4.0 L/min/m2 (range 1.2 to 5.5) to 4.8 L/min/m2 (range 1.5 to 8.03) (p < .01), and returned to its previous level 1 hr after the infusion ended (median 4.0 L/min/m2 [range 1.4 to 5.8], p < .01). During dopexamine infusion, gastric intramucosal pH improved significantly from a median baseline level of 7.21 (range 7.04 to 7.50) to 7.28 (range 7.13 to 7.46, p < .05). This improvement in gastric intramucosal pH was maintained (median 7.36 [range 7.13 to 7.46]) after the infusion ended. Indocyanine green half-life decreased but not significantly with dopexamine (medians before and during the infusion were 6.6 and 6.3 mins, respectively). Indocyanine green half-life increased significantly 1 hr after the infusion ended (median 7.4 mins [range 4.4 to 14.8], p < .05), and changes in cardiac index correlated with changes in indocyanine green half-life (Rs2 = 0.60, p < .001). Changes in gastric intramucosal pH were unrelated to all other measurements. CONCLUSIONS: Dopexamine improves gastric intramucosal pH, and thus, splanchnic oxygenation. This improvement in gastric intramucosal pH appears to be independent of dopexamine's systemic effects.

Acute Disease↗