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Biomedical subjects

M D Brown

Publications and source records attributed to M D Brown.

At least 199 records · Page 11Linked to original sources
PubMed1991

Short-term changes in renal function, blood pressure, and electrolyte levels in patients receiving cyclosporine for dermatologic disorders.

We compared the changes in renal function, blood pressure (BP), and concentrations of serum potassium, magnesium, and urate (uric acid) in two groups of patients not given transplants. Group 1, comprising 21 psoriatic patients, was treated with 14 mg/kg per day of oral cyclosporine for 4 weeks in a prospective, placebo-controlled study; group 2, comprising 28 patients with diverse cutaneous diseases, was given 6 mg/kg per day of oral cyclosporine for 1 to 3 months in a prospective, open-labeled study. Renal function (determined by serum urea nitrogen [SUN] and creatinine levels and urinalysis), BP, serum electrolyte levels (potassium and magnesium), and urate level were measured weekly for the first 4 weeks in both groups, and then, after 2 and 3 months of therapy, in group 2 only. During the first 4 weeks in group 1 patients, there were significant increases in values of SUN, creatinine, BP, potassium, and urate, and a significant decrease in the serum magnesium value. When data for the two groups were combined, the changes from pretherapy values in each of the above measures (except systolic BP) during the first 4 weeks correlated significantly with cyclosporine trough levels. In group 2, the changes that occurred in the first 4 weeks in the SUN value, SUN/creatinine ratio, and BP were magnified over the subsequent 8 weeks of treatment. In the combined group for the first 4 weeks of therapy, duration of therapy, independent of cyclosporine trough levels, correlated with changes in SUN, creatinine, and urate levels, but not with changes in the potassium or magnesium level or in BP. We conclude that the cyclosporine blood level was a better discriminant than cyclosporine dosage in the analysis of renal dysfunction and hypertension in these patients.

Adult↗
PubMed1991

Lymphatic drainage of epidural space in rabbits.

Epidural lymphatic drainage was examined using epidural catheterization and an infusion of india ink. The india ink was drained quickly through a connecting lymphatic vessel from the nerve root foramen to the anterior lumbar lymphatic vessels. Many kinds of epidurally administered agents may be drained in this manner.

Animals↗
PubMed1991

Perioperative care in lumbar spine surgery.

Attention to the details of preoperative preparation of the patient, intraoperative technique, and good postoperative care can prevent complications and increase the likelihood of successful elective lumbar spine surgery. Such relevant topics as patient education, smoking and nonsmoking patients, transfusions, and medications are included.

Blood Transfusion, Autologous↗
PubMed1990

Immediate intraoperative tissue expansion.

We report a modification of the controlled tissue expansion technique, that is, immediate intraoperative tissue expansion. The procedure is performed by placing tissue expanders at the time of surgery. After placement, three to four cycles of inflation/deflation of the expander for 3 to 5 minutes are performed. In a one-stage procedure the stretched skin is then immediately used to close the surgical defect. Three case reports demonstrating the immediate intraoperative tissue expansion technique, in which the Foley catheter balloon was used as the tissue expander, are presented. These cases illustrate that this technique may allow the surgeon to cover defects more easily with less tension and with a better cosmetic result than with other closure techniques.

Adult↗
PubMed1990

Constitutive absence and interferon-gamma-induced expression of adhesion molecules in basal cell carcinoma.

Adhesion of lymphocytes to target cells via certain cell surface molecules is important in cytotoxic T lymphocyte-mediated immune reactions. The binding of lymphocyte function-associated (LFA) antigens 1 and 2, with their respective ligands, intercellular adhesion molecule-1 (ICAM-1) and LFA-3, which are expressed on the surface of nonlymphoid cells, has been shown to be critical for lymphocyte adhesion. To determine whether basal cell carcinomas (BCCs) can escape immunodetection as a result of the inability of cytotoxic T lymphocytes to bind tumor cells, the expression of adhesion molecules on numerous BCCs, before and after exposure to interferon-gamma (IFN-gamma), was examined. Ninety-three percent of 30 freshly excised invasive BCCs did not express ICAM-1 and 73% of 11 BCCs did not express LFA-3. However, the normal-appearing basal keratinocytes in epidermis overlying nests of BCC, did express ICAM-1, particularly when a marked LFA-1+ and LFA-2+ dermal lymphocytic infiltrate was present. After BCC tissue was incubated in vitro with IFN-gamma the expression of ICAM-1 was induced on 85% of tumors studied. Thus tumor cells did not possess an absolute inability to express adhesion molecules; rather the constitutive absence of such molecules may be due to insufficient in vivo cytokine levels necessary to induce expression or a barrier preventing cytokines from reaching and interacting with tumor cells. We conclude that the absence of ICAM-1 and LFA-3 adhesion molecules is a mechanism by which BCCs can avoid immunosurveillance.

Aged↗
PubMed1990

Lymphocytic infiltrates of the skin in association with cyclosporine therapy.

Three patients, one of whom has been previously reported, had erythematous papules and nodules of the face and upper part of the chest during cyclosporine therapy for inflammatory skin diseases. Histologic examination and DNA analysis (performed in two cases) revealed benign dermal lymphocytic infiltrates. In two cases proliferation of only T cells occurred. In the third case, both T and B cell populations were expanded and there was vacuolar degeneration of the basal layer of the epidermis and IgG, IgM, and C3 deposition along the dermoepidermal junction. These findings may be the result of cyclosporine-induced immune dysregulation. The lesions resolved in all patients after therapy was stopped.

Adult↗
PubMed1990

Extensive keloids following hair transplantation.

Hair transplant surgery is a highly successful procedure for improving alopecia. However, this procedure is not without its potential risks and complications. A case of a large keloidal scar following hair transplantation is presented. Those performing hair transplant surgery should be aware of this significant potential complication, especially in Black and Oriental individuals, who are more prone to keloid formation.

Alopecia↗
PubMed1990

Lumbar disk herniation and canal stenosis: value of intraoperative sonography in diagnosis and surgical management.

One hundred four patients with preoperative diagnoses of lumbar canal stenosis, disk herniation, or a combination of both were evaluated with intraoperative sonography with the intent of (1) describing the sonographic characteristics of herniated disks and distinguishing these from bulging anuli, epidural fat, scar tissue, and spondylolisthesis; (2) establishing criteria for adequate decompression of canal stenosis; and (3) determining the usefulness of sonography in monitoring disk removal. Disk material demonstrates medium echogenicity, different in its sonographic features from bone, epidural fat, scar tissue, and epidural veins. A sonographic diagnosis of disk herniation was made in 43 cases, 41 of which were confirmed during surgery. Sonography established the presence or absence of disk herniation (confirmed by surgery) in 14 of 19 patients who had equivocal preoperative findings. After routine diskectomy, residual disk material was found in 17 (41%) of 41 patients, which led to further surgery in 16 patients with removal of the additional disk fragments. In 84 patients undergoing decompressive surgery for canal stenosis, sonography detected residual canal compression in 19 (23%), which led to a widened decompression in 15 of these patients. Sonography can differentiate disk material from other normal or abnormal structures in the canal; therefore, sonographic monitoring helps to ensure adequate bony decompression and complete diskectomy. We conclude that intraoperative sonography is an important tool in the surgical management of lumbar disk disease and stenosis.

Adipose Tissue↗
PubMed1990

The effects of chondroitinase ABC on the rabbit intervertebral disc. A roentgenographic and histologic study.

A series of intradiscal injections of chondroitinase ABC was performed in 31 young adult rabbits. Roentgenograms were taken immediately postinjection and were repeated at two, three, five, six, seven, or nine days after injection. All had roentgenographic evidence of disc space narrowing at all stages after the injection. Histologic evaluation of safranin-O fast green-stained sections indicated degradation of proteoglycans in the annulus fibrosus of chondroitinase ABC-injected discs. The cells of the chondroitinase ABC-injected discs, the end plates, and the growth-plate areas of adjacent vertebral bodies appeared unaffected.

Animals↗
PubMed1989

The effects of a concurrent infection of Trichostrongylus colubriformis and Ostertagia circumcincta on calcium, phosphorus and magnesium transactions along the digestive tract of lambs.

Twelve lambs, paired on the basis of live weight, were cannulated in the abomasum, proximal jejunum and terminal ileum. Six were infected with 3000 T. colubriformis and 3000 O. circumcincta larvae per day for 18 weeks. The other six lambs were pair-fed to the infected lambs. All animals were offered fresh ryegrass and white clover pasture, cut daily. Dry matter intake, live weight and plasma Ca, P and Mg concentrations were measured throughout the experiment. During weeks 7 and 17 post-infection, digesta flow along the gastrointestinal tract of infected and control animals was measured. Parasitism depressed dry matter intake by 60 per cent and was associated with a reduction in retention of Ca, P and Mg in both infected and control animals. During weeks 7 and 17, parasitism increased the flow of Ca past the proximal jejunum and, during week 17, the flow of P past the terminal ileum. Increased endogenous Ca and P losses, together with a net reduction in absorption of Ca and P, were associated with depressed plasma Ca and P concentrations. These findings, together with evidence of reduced addition of P to anterior regions of the tract, indicate induced Ca and P deficiency. There was evidence for compensatory absorption of Ca and P in the large intestine and distal small intestine, respectively. Magnesium metabolism was apparently not affected by parasitism.

Animals↗
PubMed1989

Cyclosporine in dermatology.

Cyclosporine is a potent immunosuppressive agent with no appreciable effect on the bone marrow and a selective inhibitory effect on helper T cells. Oral cyclosporine was first used to prevent organ rejection but also has been reported to be effective in other disorders. In cutaneous diseases that respond to oral cyclosporine helper T cells appear to be involved in their pathogenesis. This article reviews the cutaneous diseases that have been treated with cyclosporine and its pharmacology and side effects. Two significant adverse side effects are renal dysfunction and hypertension, both of which are reversible when short-term low-dose (less than 5 mg/kg per day) oral cyclosporine is discontinued. Lymphoma is unlikely in an otherwise healthy patient who has received low-dose oral cyclosporine for limited periods. The use of oral cyclosporine in any patient should be carefully considered in terms of the risk/benefit ratio and needs to be carried out under close medical supervision. In view of the limited experience with cyclosporine in dermatology, whenever possible its use should be confined to formal clinical studies with established protocols and guidelines. Further controlled studies need to be performed to evaluate the efficacy of low-dose cyclosporine in many dermatoses and its side-effect profile, particularly over the long term.

Animals↗
PubMed1989

Pain response post-chemonucleolysis or disc excision.

Eighty-five patients with proven lumbar disc displacement who had failed at least 3 months of conservative care were enrolled in this prospective study. The patients were self-selected into one of three treatment groups: collagenase, chymopapain, or surgery, based on information provided regarding the nature benefits and risks of each. Pain levels were self-recorded by patients in the post-treatment period, and follow-up physical examinations were performed and data were collected regarding hospital stay and return to activities for 3 months post-treatment. Patient's pain perception post-treatment was statistically lowest in the surgically treated group. The enzyme-injected patients reported higher levels of pain perception throughout the follow-up period, with collagenase-treated patients reporting more pain than chymopapain patients. Surgical patients had the most satisfactory outcome of treatment at 3 months. An explanation regarding the differences in pain response to the two enzymes is offered based on in vitro studies of the effects of the enzymes on the two major structural macromolecules of the connective tissue matrix.

Chymopapain↗