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Biomedical subjects

D Bryant

Publications and source records attributed to D Bryant.

At least 55 records · Page 3Linked to original sources
PubMed1992

Pedicle screw fixation in the management of unstable thoracolumbar spine injuries.

Pedicle screw fixation provides rigid segmental stabilization of the thoracolumbar spine. A wide range of conditions that can cause instability of the thoracolumbar spine can be treated using this technique. The increasing popularity of pedicle screw fixation has resulted in new knowledge concerning pedicle anatomy and the biomechanics of this method of fixation. The preliminary results have clarified both the indications and the limitations of this procedure. Successful results using pedicle screws require prudent patient selection, thorough preoperative preparation, and a high level of surgical expertise.

Biomechanical Phenomena↗
PubMed1989

A placebo-controlled dose-response study of enprofylline in the maintenance therapy of asthma.

We assessed the efficacy and side effects of oral enprofylline in the maintenance therapy of 206 asthmatics 19 to 71 yr of age. After a 1-wk placebo run-in, patients were randomized to receive in double-blind fashion one of three doses of slow-release enprofylline tablets (150 mg, 300 mg, or 450 mg twice daily) or matching placebo for 4 wk. At baseline, mean (SD) peak expiratory flow rate (PEFR) was 62 (19)% of predicted normal values. The mean increase in morning PEFR 12 h after dosing was: for 450 mg, 14(17)%; for 300 mg, 8(23)%; for 150 mg, 2(11)%, for placebo 0(10)%. The increases over baseline for 450 mg and 300 mg compared with 150 mg and placebo were statistically significant. The mean asthma symptoms score (scale zero to 3) exhibited a dose-related reduction. Significantly less beta 2-receptor agonist inhalations were used in the 450-mg group than in the placebo group. There was a statistically significant increase in headache and nausea with the doses 450 mg and 300 mg given twice daily during the first treatment week compared with 150 mg and placebo. Subsequent to the first week, there were no differences between the active treatments and placebo with respect to the incidence of these and other side effects. We conclude that oral enprofylline, in a dosage of 300 to 450 mg twice daily is an effective and well-tolerated drug that may be useful in the maintenance therapy of asthma.

Adult↗
PubMed1989

Widespread pulmonary fibrosis as a major clinical manifestation of chronic graft-versus-host disease.

A 20-year-old Chinese male given an HLA-identical sibling bone marrow transplant for severe aplastic anemia, who had previously had chronic graft-versus-host disease (GVHD) of the mouth, developed myasthenia gravis and widespread pulmonary infiltrates with cough and exertional dyspnea at day 820 post-transplant. There was nothing to suggest aspiration pneumonia. Lung histology at day 940 showed some areas of dense pulmonary fibrosis, some areas of normal parenchyma, and some areas of widening of the interstitium and a mild lymphocytic infiltrate. Evidence of infection was not found. Treatment with cyclosporin and prednisone resulted in slow partial resolution of the infiltrates over 5 months. The myasthenia gravis was controlled with pyridostigmine. In view of the association with myasthenia gravis, of the absence of infectious agents and the response to immunosuppression, we conclude that widespread pulmonary fibrosis can be a major clinical manifestation of chronic GVHD. Examination of lung tissue to distinguish this from infective interstitial pneumonitis is essential.

Adult↗
PubMed1988

Comparison of the effects of nebulized terbutaline with intravenous enprofylline in patients with acute asthma.

We compared the bronchodilating effects of intravenously administered enprofylline (2 mg/kg) with nebulized terbutaline (10 mg) in patients presenting to hospital with acute asthma in a multicenter double-blind parallel study. One hundred twenty three patients were randomized into the study, and 69 of these fulfilled the inclusion criteria and a retrospective time to study entry criterion; 34 received enprofylline and 35 received terbutaline. There was no significant difference in maximum increase in forced expired volume in 1 second (FEV1) between the enprofylline group (0.24 +/- 0.33 L) and the terbutaline group (0.25 +/- 0.28 L) (p greater than 0.05), nor for the increase in FEV1 over the 1-hour study period. Tremor was reported more in the group receiving terbutaline, and nausea was reported more in the group receiving enprofylline. Two patients experienced hypotension and one patient had a vasovagal episode with enprofylline treatment. Both agents acted as bronchodilators with similar efficacy in patients with acute asthma in this study.

Acute Disease↗
PubMed1984

The significance of monocytes in glomeruli of human renal transplants.

A total of 50 biopsies from 42 renal transplants obtained during a 30-month period were studied for the presence of monocytes in the glomeruli using the nonspecific esterase reaction. Eleven biopsies from ten grafts were positive. Immune deposition was light or absent. The prognosis for the grafts containing glomerular monocytes was significantly worse during the six months after the biopsy than for those without such cells present.

Esterases↗
PubMed1983

Acquired immune deficiency syndrome.

The first Australian case of acquired immune deficiency syndrome (AIDS), which occurred in a 27-year-old homosexual man, is reported. The patient, an American citizen now resident in Sydney, presented with life-threatening pulmonary consolidation. AIDS is characterized by severe defects in cell-mediated immunity associated with infections and neoplasms (most commonly Pneumocystis carinii pneumonia and Kaposi's sarcoma). The cause of the syndrome is unknown, but it may be a new infectious agent.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Site-directed point mutation in the src gene oF rous sarcoma virus results in an inactive src gene product.

Site-directed mutagenesis techniques were used to construct defined point mutations within the src gene of the Prague A strain of Rous sarcoma virus. Bisulfite mutagenesis at a Bg/I restriction site in the src gene yielded three mutations which contained the same single base change, a guanine-to-adenine transition. The resulting genomes encoded an src protein containing a substitution of threonine for alanine at amino acid position 433. Transfection of chicken cells with mutagenized DNA did not result in cellular transformation even though the cells produced a pp60src. Immune complexes containing mutant pp60src did not phosphorylate immunoglobulin G heavy chain or casein.

Animals↗
PubMed1982

Site-directed mutagenesis of the src gene of Rous sarcoma virus: construction and characterization of a deletion mutant temperature sensitive for transformation.

Transformation of cells by Rous sarcoma virus results from the expression of the viral src gene product, pp60src. Site-directed mutagenesis techniques have been used to construct defined deletion mutations within the src gene of Prague A strain of Rous sarcoma virus. The deletion of DNA sequences at the Bg/II restriction site in the src gene yielded both transformation-defective mutants (tdCH4, 64, and 146) and a mutant temperature sensitive for morphological transformation (tsCH119). The genome of tsCH119 contains an in-phase deletion of approximately 160 base pairs, which mapped to the immediate 3' side of the Bg/II restriction site. Upon infection of chicken cells, tsCH119 encoded a structurally altered src protein, pp53src, containing a deletion of amino acid residues 202 to 255. Immune complexes containing pp53src isolated from tsCH119-infected cells grown at 41 degrees C exhibited only 50% less tyrosine-specific kinase activity than immune complexes isolated from cells grown at 35 degrees C. pp53src immunoprecipitated from tsCH119-infected cells grown at either 35 or 41 degrees C contained phosphoserine and phosphotyrosine. We suggest that tsCH119 represents a class of mutants containing mutations mapping within a functionally important domain of the src protein, distinct from the domain specifying the protein kinase activity.

Animals↗
PubMed1982

The detection of monocytes in human renal biopsies: a prospective study.

A total of 52 non-transplant and 16 transplant renal biopsies were examined for the presence of monocytes in the glomeruli using the non-specific esterase reaction. Four of the non-transplant and 4 of the transplant group were positive. The 4 non-transplant samples all showed the presence of granular IgG and C3 together with electron dense deposits in the basement membrane. In contrast the positive transplant samples showed vascular rejection with little immune protein deposition and no deposits. One patient with focal glomerulosclerosis had large clumps of esterase positive material in the glomeruli in association with deposits of C3 and the presence of foam cells.

Fluorescent Antibody Technique↗
PubMed1981

Effect of secretin on intestinal lymph flow and composition in the rat.

The effects of natural porcine and synthetic secretin, given by intravenous bolus or infusion, on intestinal lymph flow and protein composition in unanaesthetized rats were studied. Both forms of secretin increased lymph flow and protein output from the lymph fistula; dose-response relationships were determined. No change was observed in protein concentration in lymph or in the relative concentrations of large and small protein molecules during secretin-induced enhanced lymph flow, compared with the basal state. These results are in keeping with an increase in the functional exchange vessel area of the small intestine produced by secretin. It is possible that secretin may play a part in the hyperaemia and augmented intestinal lymph flow which occurs in the post-prandial period.

Animals↗
PubMed1980

Diphenhydramine reduces endotoxin effects on lung vascular permeability in sheep.

Because, in sheep, histamine-induced increased lung vascular permeability is prevented by diphenhydramine, we tested the effects of diphenhydramine on the sheep lung vascular response to endotoxin. We infused E. coli endotoxin (0.40-1.00 micrograms/kg) with and without diphenhydramine (3.0 mg/kg bolus + 1.5 mg . kg-1 . h-1) in the same unanesthetized sheep while measuring pulmonary arterial (Ppa) and left atrial (Pla) pressures, lung lymph flow (Qlym) and lymph (L) and plasma (P) protein concentrations. Endotoxin caused pulmonary hypertension soon after infusion (base-line Ppa = 22 +/- 3 (SE) cmH2O; after endotoxin Ppa = 40 +/- 2; P less than 0.05, n = 6) and after several hours an increase in permeability reflected in high flow of protein-rich lymph (base-line; Qlym = 7.5 +/- 1.4 (SE) ml/h, L/P protein concentration = 0.60 +/- 0.02: after endotoxin; Qlym = 21.4 +/- 3.1, P less than 0.05; L/P = 0.66 +/- 0.03, P less than 0.05). In the presence of diphenhydramine, endotoxin caused identical pressure changes but Qlym was lower during the period of increased permeability (16.7 +/- 3.0 (SE) ml/h, P less than 0.05 compared to endotoxin alone) and L/P protein concentration was similar (0.68 +/- 0.04, P = NS). We conclude that endogenous histamine may be partly responsible for the increase in lung vascular permeability after endotoxemia, but that histamine probably is not the sole mediator of the permeability change.

Animals↗
PubMed1980

Some circulating factors which influence granulocyte-monocyte production in the chick with myeloblastic leukemia.

Soft-agar cloning was used to investigate possible granulopoietic-monopoietic regulatory defects in the chick with myeloblastic leukemia induced by avian myeloblastosis virus. The plasma levels of granulocyte-monocyte colony-stimulating activity (CSA) of normal and leukemic plasmas were the same when undiluted or unfractionated plasmas were tested. However, dilution or fractionation revealed elevations in plasma CSA levels in the leukemic animals. Most of the activity in both normal and leukemic plasma eluted in the void-volume peak during Sephadex G-200 gel filtration, and the CSA levels in the leukemic peak were increased 5- to 10-fold. This increase did not reflect higher levels of an inhibitory lipoprotein eluting in the void volume since the differential between normal and leukemic plasma was present after delipidation. We therefore investigated the possibility that a nonlipoprotein inhibitor was present. Sephadex G-200 chromatography of leukemic plasma revealed that a potent inhibitor of colony formation was present in one of the peaks of material eluting from the column. Eight micrograms of this material inhibited colony formation by 50%. This inhibitory material was not detected in corresponding fractions obtained after chromatography of normal plasma. These data show that plasma from the chick with myeloblastic leukemia has marked elevated levels of CSA and that it also contains an inhibitor of colony formation which is absent or present at very low levels in normal plasma. Finally, leukemic plasma contained abundant amounts of avian myeloblastosis virus polypeptides which are being investigated for possible relationships to the above-described activities.

Animals↗