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Biomedical subjects

R Hu

Publications and source records attributed to R Hu.

At least 19 recordsLinked to original sources
PubMed1992

Distribution of Ixodes dammini (Acari: Ixodidae) in residential lawns on Prudence Island, Rhode Island.

The distribution of nymphal Ixodes dammini Spielman, Clifford, Piesman & Corwin in residential lawns was assessed by flagging on Prudence Island, RI. The number of ticks per sample was five times greater in lawns adjacent to woods than in lawns adjacent to other lawns. Relative tick abundance was negatively correlated with distance from the woods, but the decline was gradual. Spirochete prevalence in ticks did not differ among lawn types or at different distances from the woods. Therefore, barriers that keep people away from the wood edge probably lower the risk of acquiring Lyme disease, but there is still a risk. Even with physical barriers at lawn-wood edges, personal precautions to prevent tick bites should be followed.

Animals↗
PubMed1992

HLA class II genes in Graves' disease.

Inheritance of Graves' disease has been linked to the HA-DR3 gene product which may function in some specific way in antigen presentation. To determine whether the first extracellular domain of this protein, which is specifically involved in antigen presentation, has the same sequence in patients with Graves' disease and in normal individuals, we have amplified the second exon using the polymerase chain reaction, and then cloned and sequenced the DNA segment. In eight subjects with Graves' disease, sequences identical to prototypic reported sequence for DRB1*0301 were recovered, and in two individuals sequences varied by a few nucleotides, leading to 1-3 amino acid substitutions which did not occur in a pattern. Sequences identical to the prototypic sequence known as DRB3*0101, also previously known as DRw52, were also recovered. Thus the HLA-DRB1 and B3 genes present in patients with autoimmune disease appear to be the same as those present in the general population. These observations indicate that a unique allele is not present in patients with autoimmune disease, but rather that the normal DR3 allele itself, in a manner yet to be described, increases the probability of developing autoimmune thyroid disease.

Amino Acid Sequence↗
PubMed1992

Drill sleeve for pedicle screw fixation.

Pedicle screw fixation is a popular method of fixation of the spine. Placement of screw and prevention of injury are surgeon dependent. We describe an easily made drill sleeve and depth gauge to assist in the preparation of the vertebral pedicle for pedicle screw application. Use of this device will help prevent soft tissue injury and overpenetration of the drill in the vertebral body.

Bone Screws↗
PubMed1991

Detection apparatus for multiple heterogeneous chemiluminescence immunoassay configurations.

We describe an apparatus for measuring signals emanated from two heterogeneous chemiluminescence immunoassay (CLIA) configurations: antibody-coated polystyrene beads, in reaction tray wells, and microparticles captured by a porous matrix. An optics and fluidics design which allows the use of a common detection head for these two different assay configurations is described. The detection head moves along three Cartesian coordinates to create a localized light-tight compartment around each individual disposable reaction vessel. Reproducibility of the light seal, trigger solution delivery, and mixing is achieved for acridinium-labeled CLIA. The coated polystyrene beads configuration is tested using beta HCG, CEA, and TSH assays. The microparticle-capture configuration is tested using beta HCG and HBsAg assays. The microparticle capture CLIA has shorter incubation times and the potential for ease of automation.

Data Interpretation, Statistical↗
PubMed1991

Improvement in the specificity of assays for detection of antibody to hepatitis B core antigen.

Reducing agents dramatically alter the specificity of competitive assays for antibody to hepatitis B core antigen (anti-HBc). A specificity improvement was demonstrated with a new assay which utilizes microparticle membrane capture and chemiluminescence detection as well as a current radioimmunoassay procedure (Corab: Abbott Laboratories, Abbott Park, Ill.). The effect was most noticeable with elevated negative and weakly reactive samples. In both systems, reductants increased separation of a negative population (n = 160) from assay cutoffs. With a selected population (n = 307), inclusion of reductant eliminated apparent anti-HBc activity in 54 of 81 samples in the 30 to 70% inhibition range. Reductant-stable anti-HBc samples were strongly associated with the presence of antibody to hepatitis B surface antigen (21 of 27). The association persisted below the detection limits of current assays to 0.3 to 0.4 Paul Ehrlich Institute units per ml. Only 1 of 54 reduction-sensitive borderline samples was confirmed to be positive for antibody to hepatitis B surface antigen. The modified procedures had unchanged or slightly improved sensitivity for immunoglobulin G (IgG)-associated anti-HBc activity. Although IgM anti-HBc detection was reduced from four- to eightfold in the presence of reductants, sensitivities remained at least twofold greater than tha of an enzyme immunoassay (Corzyme M; Abbott) designed to detect acute-phase levels of IgM anti-HBc. The use of reducing agents should significantly improve the reliability of anti-HBc testing, especially near assay cutoffs.

Binding, Competitive↗
PubMed1990

[Changes in serum thyroid hormones in acute cerebrovascular apoplexy and their clinical significance].

Serum thyroid hormones were measured in 62 cases of acute cerebrovascular apoplexy. Compared with the control group, T3, FT3 were markedly lowered and rT3, T4 and TSH were significantly increased with lowered T3/rT3 ratio. The patients were divided into two groups, according to whether there was hemorrhage in their CSF. Changes of serum thyroid hormones in cerebral haemorrhage were more remarkable than those observed in cerebral thrombosis. 16 cases with increased T4, FT4 were diagnosed as euthyroid hyperthyroxinemia. It was found that the amount of thyroid hormone changes appeared to be in proportion to the severity of acute cerebrovascular apoplexy. The determination of serum thyroid hormones would be useful in evaluating the severity of the strokes and in studying the thyroid function in acute cerebrovascular apoplexy.

Adult↗
PubMed1989

Prophylaxis of deep-vein thrombosis in total hip surgery.

Thromboembolism is a common and serious complication of total hip replacement. Methods of prophylaxis include combinations of physical compression of the legs and anticoagulation. Results of treatment are difficult to document and quantitate. The authors reviewed 122 patients who underwent hip arthroplasty with intermittent pneumatic calf compression, intravenous administration of dextran and platelet inhibitors. In 20% of them, clinically suspected pulmonary embolism was confirmed by ventilation perfusion lung scanning. The true incidence of pulmonary embolism is probably greater than this and it appears that the prophylactic regimen used in this study does not confer any benefit.

Clothing↗
PubMed1989

Bone banking in Canada: a review.

Transplantation of human tissues has become increasingly popular, and associated with this increase are reports of the transmission of diseases including acquired immune deficiency syndrome. To reduce the risk of transmitting disease through transplantation, careful scrutiny of current tissue transplantation procedures is necessary. Bone banking in Canada was evaluated by questionnaire, sent to the head operating room nurse of every Canadian hospital listed in the 1986 Canadian Medical Directory as having 100 or more beds. From this questionnaire, the authors identified 60 bone banks in Canada, many of which failed to meet recommended guidelines. The authors review the literature relating to bone banking procedures and present in detail the results of their survey.

Adolescent↗
PubMed1988

Characterization of two monoclonal antibodies in an immunohistochemical study of keratin 8 and 18 expression.

Two monoclonal antibodies, UCD/AB 6.11 and UCD/PR 10.11, were evaluated for their patterns of immunohistochemical reactivity in a survey of paraffin-embedded human tissues by the avidin-biotin-immunoperoxidase technique. By two-dimensional immunoblotting, UCD/AB 6.11 reacts with keratin number 18 and UCD/PR 10.11 identifies both keratin numbers 8 and 18, the major keratins found in human simple epithelial cells. Both antibodies have excellent signal-to-noise ratios, and specifically react with simple epithelia, transitional epithelia, mesothelia and tumors derived from such tissues, making them superior immunological reagents. They do not react with neural, muscle, hematopoietic, connective or most epidermal tissues. However, within a given tissue or cell type, differences in the distributions of the antigens recognized by these two antibodies can be observed, raising the possibility of differential expression, modification, or masking of the keratin epitopes revealed by UCD/AB 6.11 and UCD/PR 10.11.

Antibodies, Monoclonal↗
PubMed1988

The nonoperative treatment of burst fractures of the thoracolumbar junction.

Treatment of thoracolumbar spine burst fracture with a neurologically intact patient is controversial, with advocates of operative and nonoperative approaches. Of 404 patients in a prospective spinal trauma study, 21 had burst fractures, were neurologically intact, and had greater than 1-year followup. This group was analyzed to evaluate treatment with early mobilization using a thoracolumbar total contact orthosis. The average time in a brace was 6 months. Two patients had pulmonary embolus treated successfully with anticoagulants. No patient required subsequent surgery for increasing kyphosis or neurologic deficit. Change in K angle at followup was 4.6 degrees (+/- 5.7) and change in anterior vertebral height was 6.1 degrees (+/- 10). All patients had a satisfactory pain score and most individuals returned to full employment. It is concluded that it is not necessary to routinely treat patients operatively with burst fractures if they fulfill the following criteria: 1) neurologically intact; 2) kyphosis angle less than 35 degrees; 3) other injuries do not preclude the use of a total contact orthosis; and 4) the patient is capable of understanding and cooperating with the treatment regime. These criteria are irrespective of the CT findings of posterior vertebral retropulsion and spinal canal narrowing.

Adolescent↗
PubMed1987

Immunological activities of recombinant interferon-alpha 2 and its A fragment.

The immunomodulating effects of the A fragment of recombinant human interferon-alpha 2 (rIFN-alpha 2) generated by thermolysin treatment was compared to that of the intact rIFN-alpha 2 and lymphoblastoid IFN. The A fragment was similar to intact IFN in augmenting natural killer (NK) activity and suppressing the proliferation of certain cell lines, but it failed to inhibit human polyclonal immunoglobulin production; rIFN-alpha 2 and lymphoblastoid IFN were equally effective in suppressing this in vitro system. These data suggest that the A fragment mediates certain, but not all, of the immunomodulating properties of IFN-alpha 2.

Antibody Formation↗
PubMed1986

Analysis of the steady state binding, internalization, and degradation of human interferon-alpha2.

Scatchard analyses of the equilibrium binding of radiolabeled human interferon-alpha2 (huIFN-alpha2) to Madin-Darby bovine kidney cells previously exposed to subsaturating concentrations of IFN-alpha showed approximately a 50% decrease in the number of cell surface receptors and no change in the apparent dissociation constant, Kd, compared with cells not exposed to interferon. The steady state equations describing the interaction of polypeptide ligands with cell surface receptors under physiological conditions (Wiley, H.S., and Cunningham, D.D. (1981) Cell 25, 433-440) have allowed us to determine, under steady state conditions, the rate of insertion of receptors into the cell membrane, the endocytic rate constant of occupied receptors, the rate constant of turnover of unoccupied receptors, and the rate of hydrolysis of internalized ligand. Our results indicate that occupied and unoccupied interferon receptors are cleared from the cell surface at approximately the same rate. This suggests that the down-regulation of the huIFN-alpha2 receptor on Madin-Darby bovine kidney cells by huIFN-alpha2 differs from that of several other surface receptors for polypeptide hormones and growth factors analyzed on cultured cells in that the binding of huIFN-alpha2 to its receptor does not increase the rate of receptor endocytosis.

Animals↗