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Biomedical subjects

F E Brown

Publications and source records attributed to F E Brown.

15 recordsLinked to original sources
PubMed1992

Pathways of coagulation activation in situ in rheumatoid synovial tissue.

Immunohistochemical techniques were applied to rheumatoid synovium in order to detect components of coagulation and fibrinolysis pathways within these tissues. These techniques revealed an intact coagulation pathway and plasminogen activator inhibitor-2 associated with macrophage-like cells that were present throughout these tissues, especially in subsurface areas. Cell-associated thrombin generation appeared to account for conversion of abundant fibrinogen to fibrin. Occasional macrophage-like cells also stained for urokinase but tissue-type plasminogen activator and plasminogen activator inhibitor-1 were restricted to vascular endothelium. Intense synovial fibrin deposition (with the limited evidence for associated fibrinolysis) may contribute to local inflammation and explain certain clinical features of rheumatoid arthritis. These findings suggest novel treatment hypotheses for this disease.

Arthritis, Rheumatoid↗
PubMed1992

Frequency and intensity discrimination in Mongolian gerbils, African monkeys and humans.

Frequency (delta F) and intensity (delta I) difference limens were directly compared in Mongolian gerbils (Meriones unguiculatus), Old World African Monkeys (Cercopithecus mitis, Cercocebus albigena), and humans. Methods employed a repeating background AX discrimination procedure, and positive (food) reinforcement for animals. For delta I, there were small quantitative differences between the species. At 1 kHz, 70 dB SPL, DLs averaged 2.82 dB for gerbils, 2.29 dB for monkeys, and 0.75 dB for humans. For delta F, there were larger differences between the species. At 1 kHz, 60 dB SPL, frequency DLs were highest for gerbils, averaging 108 Hz. DLs were lower for monkeys, averaging 32.6 Hz, similar to recently reported DLs for other Old World monkeys (Prosen et al., 1990). Human DLs, averaging 2.27 Hz, were markedly lower than those of either monkeys or gerbils. These results suggest that animals provide better models of human delta I than delta F.

Acoustic Stimulation↗
PubMed1991

Neuroleptic malignant syndrome: occurrence in a child after reconstructive surgery.

The occurrence of the rare but potentially fatal neuroleptic malignant syndrome must be considered by the surgeon treating a patient who develops hyperthermia, mental abnormalities, autonomic instability, and muscle rigidity after exposure to phenothiazines or other neuroleptic drugs. The dopamine agonist bromocriptine appears to be the treatment of choice in adults and seemed to be effective and well tolerated in our patient. Although the syndrome cannot be prevented, recognition is crucial, since effective general and specific therapy is available. Differentiating neuroleptic malignant syndrome from malignant hyperthermia allows early appropriate treatment with bromocriptine.

Child↗
PubMed1990

Overview of experience of Tanzer's group with microtia.

A review of our patients since Dr. Tanzer's retirement in 1970 shows good and lasting results after reconstruction of microtia using autogenous cartilage frameworks and staged procedures. There has been no evidence of shrinkage or distortion of the cartilage in any of our own patients, and the majority of them are pleased with their ears. With a cooperative and well-motivated patient and surgeons who are skilled and experienced in the procedure, ears can be made with a relatively normal size, shape, and position to match closely the other side. We continue to feel strongly that autogenous cartilage is the safest and best material to use for the ear framework. At some time in the future the body may be taught to accept homografts as if they were its own tissue, and allografts may be available that are tolerated as well as living tissue. Until then we will rely on autogenous tissue and our present techniques, which have produced long-lasting good results. Altogether the combined experience with ear reconstruction of Tanzer's group at the Dartmouth-Hitchcock Medical Center spans more than 30 years.

Adolescent↗
PubMed1988

Long-term results after tenosynovectomy to treat the rheumatoid hand.

To be effective as a prophylactic procedure, tenosynovectomy to treat rheumatoid hand has to be done before there is significant tendon damage. Tenosynovectomy is usually considered to prevent subsequent tendon rupture and recurrent tenosynovitis. We reviewed the results of all tenosynovectomies done at the Dartmouth-Hitchcock Medical Center from 1968 to 1983. One hundred seventy-three procedures were done for 125 patients. Fifty percent of patients who had prophylactic tenosynovectomy demonstrated tendon invasion. Examination at a mean of 70 months after 129 procedures showed extensor tendon failure in 1 patient of 44 who had normal tendons, 1 of 42 with invaded tendons, and in 3 of 43 who had ruptured tendons at the time of original surgery. Seven patients had recurrent tenosynovitis.

Arthritis, Rheumatoid↗
PubMed1987

Nonspecific cytotoxic cells in fish (Ictalurus punctatus). VI. Flow cytometric analysis.

Nonspecific cytotoxic cells (NCC) from channel catfish (Ictalurus punctatus) were enriched using flow cytometry (EPICS V, 753). Parameters of forward angle and 90 degrees light scatter were utilized to sort cytolytically functional populations of NCC. Fullbright (GR. II) 9.75 microns diameter fluorescent polystyrene microspheres were used for optical alignment. Cells obtained from the anterior kidney, spleen and peripheral blood were analyzed by one and/or two parameters of forward angle light scatter (FALS) and log integral 90 degrees light scatter (L90 degrees LS). Populations identified from FALS or L90 degrees LS histograms were sorted and cells were tested for cytotoxicity against NC-37 target cells. Anterior kidney contained at least four different sized populations of NCC. Spleen cells were sorted by FALS and four different populations of NCC detected. Peripheral blood contained little NCC activity. Enrichment of NCC activity from anterior kidney tissue was compared using Percoll density gradient separation and flow cytometry. Three to four fold higher cytotoxic activity was obtained from sorted cells compared to the population obtained from 45.5% Percoll. Additional experiments to determine the enrichment of sorted NCC were conducted by analyzing the number of enriched NCC required to kill an individual NC-37 target cell. Approximately 1.5-2.0 NCC could lyse a chromium-51 labelled target cell. These studies demonstrated that NCC could be enriched by size and granularity discrimination using flow cytometry. Effector:target cell ratios of 10:1 and lower produced significant lysis when sorted cells were analyzed.

Animals↗
PubMed1987

Mammographic changes following reduction mammaplasty.

Mammographic findings after reduction mammaplasty may be similar to those seen with carcinoma. A knowledge of the expected mammographic alterations would be helpful in differentiating postoperative changes from those seen with carcinoma of the breast. Accordingly, the clinical records and mammograms of patients who underwent reduction mammaplasty at the Dartmouth-Hitchcock Medical Center between March of 1977 and July of 1985 were analyzed. Forty-two patients had at least one mammographic examination following reduction mammaplasty. Periareolar soft-tissue changes and inferior pole alterations were present in almost all examinations of patients during the first 6 months after operation, but they decreased during the next few years. Asymmetrical densities were present in approximately half the patients throughout the follow-up period but decreased in degree. Parenchymal calcifications occurred later; few x-rays showed these calcifications during the first year, but 50 percent were apparent after 2 years. Evidence of fat necrosis occurred in approximately 10 percent. Four patients had biopsies for suspicious densities. Chronic inflammation and inclusion cyst were reported. We believe that changes after reduction mammaplasty are predictable and can usually be differentiated from those associated with cancer.

Adipose Tissue↗
PubMed1987

Thumb polydactyly as a part of the range of genetic expression for thenar hypoplasia.

Attempts to study the genetics of human thumb polydactyly have been hampered by lack of awareness of the extremely varied expression of upper limb preaxial anomalies. It has been appreciated that thumb polydactyly could range from a broadened distal phalanx to complete duplication of the entire thumb. Most cases are sporadic and unilateral, but rare familial cases with wide variability and occasional nonpenetrance have been described. Four unrelated families are described who have thumb polydactyly as part of the range of expression for a dominant gene that is frequently associated with absence of thenar intrinsic muscles and flexor pollicis longus with inability to flex the thumb across the palm (the Fromont anomaly). These families and previous literature reports suggest that expression of the gene can range from thumb hypoplasia (most commonly the Fromont anomaly) to triphalangeal thumb or thumb polydactyly. As a consequence of this experience, we urge that parents, siblings, and other close relatives of patients born with thumb polydactyly be carefully examined for mild degrees of thumb hypoplasia or any other thumb anomaly, and that these findings be considered when providing recurrence risk counseling.

Adolescent↗
PubMed1986

Induced vasodilation in the treatment of posttraumatic digital cold intolerance.

Induced vasodilation was used in 10 patients with posttraumatic cold intolerance. Eight of 10 patients improved. Before the treatment program and cold exposure, the injured digits were an average of 1.5 degrees C cooler than the control digits. After cold exposure, the mean temperature difference was 3.2 degrees C. At the conclusion of the study, the temperature differences between the injured and control digits were an average of 0.1 degree C before cold stress and 1.0 degree C after. Associated with this measured improvement was an improvement in cold tolerance. This was maintained 1 year later by 67% of the patients. One year after the completion of this study, nine patients were treated at home on a less controlled program with improvement in 67% of patients.

Adaptation, Physiological↗
PubMed1986

Dominantly inherited unilateral terminal transverse defects of the hand (adactylia) in twin sisters and one daughter.

Most previous cases of unilateral terminal transverse defects of the hand have not been familial. Several previously reported cases of apparent autosomal dominant inheritance of such defects have subsequently been reclassified as type B brachydactyly. We report a pair of adult twin women with unilateral terminal transverse defects affecting the left hand in one woman and the right hand in the other woman. The latter woman has one daughter with a unilateral terminal transverse defect affecting the left hand. The hand anomaly is characterized by absence of the terminal portions of digits 2 to 5 with a mildly hypoplastic thumb (adactylia). Tiny nail remnants are evident on the remaining digital stumps, and no soft tissue syndactyly is apparent. At 2 years of age, the daughter has hypoplastic first, fourth, and fifth metacarpals with no ossification of the second or third metacarpals or any of the phalanges. The affected mother has hypoplastic metacarpals for digits 2 to 4 and a vestigial fifth proximal phalanx on the affected hand, with no other phalanges evident by roentgenogram other than those of the thumb. The mother's twin sister has similar findings, except the ossified phalangeal remnant is on her second and third fingers rather than her fifth finger. Doppler flow arterial patterns appeared normal in each hand of affected family members. The other hand and both feet are clinically and radiologically normal in each case, and the family history is negative for any other individuals with limb anomalies. A review of the literature suggests that this family may very well be unique.

Adult↗
PubMed1986

Correction of congenital auricular deformities by splinting in the neonatal period.

Many congenital ear deformities involve abnormal plical folding. This appears to be a result of deficient intrinsic and extrinsic auricular muscle activity as well as intrauterine pressure effects. These deformities can usually be corrected by appropriate splinting in the neonatal period, a time when estrogen activity is increased and the ear is very malleable. The methods used and the results of treatment are presented.

Ear, External↗
PubMedDate not supplied

Collagenolytic systems in rheumatoid arthritis.

As the proliferative lesion of rheumatoid arthritis becomes polarized and invasion of articular cartilage and subchondral bone begins, it is likely that many mesenchymal cells, including periosteal and perichondral cells, and perhaps even the chondrocytes and osteoblasts themselves can be activated to produce destructive enzymes. Early in the course of RA cartilage proteoglycans are depleted, leaving the remaining collagen more susceptible to mechanical breakdown as well as to enzymatic breakdown. Specific collagenases are released by synovial cells and, in addition, by polymorphonuclear leukocytes. The latter enzyme may account for free collagenase found in synovial fluid, a finding possibly related to saturation of inhibitory proteins by proteases with greater affinity for them, leaving collagenase active. At this time in the course of rheumatoid arthritis, a joint would be under double jeopardy from enzymes released by the invading pannus as well as by collagenase free and active in the synovial fluid. Rapid destruction could occur. Although cartilage collagen has an intrinsic resistance to collagenase conferred by its primary structure and by higher order structure (e.g. intermolecular cross-links), it seems wise to cool down hot joints because increased temperature may increase the rate of collagen degradation and, therefore, cartilage destruction. In addition, superimposed sepsis or acute flares of rheumatoid disease result in enough influx of polymorphonuclear leukocytes into the joints to result in free collagenolytic activity being present. This provides a rationale for frequent aspiration of any joint fluid, septic or otherwise, containing high polymorphonuclear leukocyte counts.

Adult↗