Biomedical subjects
D H Brown
Publications and source records attributed to D H Brown.
A simplified method of tracheoesophageal puncture for speech restoration.
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Pharyngeal rhabdomyoma: a clinico-pathological study.
Adult extracardiac rhabdomyomas are rare with only 33 head and neck cases being reported in the world literature. In this select group, only nine cases have been found in the pharynx. We present two cases of pharyngeal rhabdomyoma focusing on the imaging findings, surgical approaches and more specifically on the histopathological and electron microscopic diagnosis of this interesting lesion. It is important to differentiate this tumor from other neoplasms, including granular cell myoblastoma, rhabdomyosarcomas, hamartomas, and fetal rhabdomyomas.
An unusual complication of tracheoesophageal puncture for speech restoration.
Prosthetic voice rehabilitation post-laryngectomy is becoming more popular with otolaryngologists in Canada. However, as with any procedure, surgeons must be aware of potential complications. We present the first detailed report of a case in the creation of a dissecting false passage following tracheoesophageal puncture.
Blindness: a potential complication of bilateral neck dissection.
Permanent blindness, is a very rare, but devastating complication of simultaneous bilateral neck dissection. Most otolaryngologists/head and neck surgeons are unaware that amaurosis can result from this surgery, and this paper is meant as a poignant reminder of that end. A case report is presented, followed by a discussion of possible aetiology; a management protocol is proposed.
Comparative study of the sensitivity of head and neck cell lines to methotrexate (MTX) and the analog 10-ethyl, 10-deazaaminopterin (10-EdAM).
Squamous cell lines cultured in vitro provide a potential test system for the selection of analogs that have an improved therapeutic index. The growth inhibitory effects of methotrexate and the new folate analog 10-ethyl, 10-deazaaminopterin were compared in three in vitro-cultured human head and neck squamous cell carcinoma cell lines. The inhibitory concentrations of the new analog were 10- to 100-fold lower than the inhibitory concentrations of methotrexate. The sensitivity of these three head and neck squamous cell carcinoma cell lines to both drugs was essentially the same as the sensitivity of a rhabdomyosarcoma cell line known to be very sensitive to methotrexate when the cell line is grown as a xenograft in athymic nude mice. These data indicate that 10-ethyl, 10-deazaaminopterin may be a new and effective agent against head and neck squamous cell carcinoma.
Branching enzyme activity of cultured amniocytes and chorionic villi: prenatal testing for type IV glycogen storage disease.
Although type IV glycogen storage disease (Andersen disease; McKusick 23250) is considered to be a rare, autosomally recessive disorder, of the more than 600 patients with glycogenosis identified in our laboratory by enzymatic assays, 6% have been shown to be deficient in the glycogen branching enzyme. Most of the 38 patients with type IV glycogen storage disease who are known to us have succumbed at a very early age, with the exception of one male teenager, an apparently healthy 7-year-old male, and several 5-year-old patients. Fourteen pregnancies at risk for branching enzyme deficiency have been monitored using cultured amniotic fluid cells, and four additional pregnancies have been screened using cultured chorionic villi. Essentially no branching enzyme activity was detectable in eight samples (amniocytes); activities within the control range were found in five samples (three amniocyte and two chorionic villi samples); and five samples appeared to have been derived from carriers. In two of the cases lacking branching enzyme activity, in which the pregnancies were terminated and fibroblasts were successfully cultured from the aborted fetuses, no branching enzyme activity was found. Another fetus, which was predicted by antenatal assay to be affected, was carried to term. Skin fibroblasts from this baby were deficient in branching enzyme. Pregnancies at risk for glycogen storage disease due to the deficiency of branching enzyme can be successfully monitored using either cultured chorionic villi or amniocytes.
The Le Fort I maxillary osteotomy approach to surgery of the skull base.
A new modification of the transoral route involving a Le Fort I maxillotomy has been developed to offer much-improved exposure of the midline skull base. The procedure involves a standard Le Fort I osteotomy combined with division of the nasal septum and lateral pterygoid laminae, and excision of the inferior turbinates and vomer. With insertion of a modified Dingman gag, exposure is gained from the pituitary fossa to the arch of the atlas. The approach has been successfully employed to resect eight different skull base lesions, both intracranially and extracranially, in 20 operations involving 17 patients. Complications and morbidity were minimal. Postoperative cosmetic results and occlusion were excellent. The Le Fort I maxillotomy approach has distinct advantages in dealing with a whole spectrum of pathology around the clivus and postnasal space.
Mycotic sinusitis: a management protocol.
There has been a recent increase in reported cases of fungal sinusitis. This may be due to better awareness and improved histopathological methods as well as increasing numbers of immunologically compromised patients. We present a case of mycotic sinusitis in an immunocompetent individual to emphasize the clinical features of this disease. The pathology and microbiology are analyzed and a management protocol is discussed.
Resonance Raman spectroscopy of hemoglobin in intact cells: a probe of oxygen uptake by erythrocytes in rheumatoid arthritis.
Resonance Raman spectra from intact viable erythrocytes can be used to study oxygen uptake in solution. In addition to changes in the oxidation state marker (nu 4), other bands due to the porphyrin ring (nu 3) and vinyl modes indicate subtle changes at oxygen pressures close to where the T/R change occurs. A comparison of whole cell and lysate spectra indicates a partial denaturation of hemoglobin on lysis. A simple smear technique is used to measure spectra from rheumatoid and normal blood. Results indicate a faster but less complete uptake of oxygen in cells from patients with rheumatoid arthritis than is the case in normal cell populations.
The membrane rupture theory of Menière's disease--is it valid?
The Membrane Rupture Theory states that the acute attack of Menière's disease occurs when endolymph, with its high potassium ion concentration, escapes into the perilymph and surrounds the first-order neuron. Initially, this causes partial depolarization of the nerve and an increased resting discharge, followed by complete depolarization. Clinically, one would expect an initial irritative nystagmus (toward the affected side) followed by a paralytic nystagmus (toward the unaffected side). To confirm this, the guinea pig perilymphatic space was perfused with an artificial endolymph solution. The results confirmed an irritative/paralytic sequence of nystagmus that differs from the pattern of spontaneous nystagmus observed with ENG monitoring during the acute attack of Menière's disease. Early in the attack, one observes a paralytic nystagmus followed by a secondary nystagmus beating toward the affected side (similar to an irritative nystagmus) as the patient recovers. This raises questions about the validity of the Membrane Rupture Theory.
Orbital pseudotumors.
Orbital pseudotumor is a clinical entity characterized by features of a space-occupying, non-specific inflammatory condition of the orbit. Diagnosis can be difficult, and the patient will often initially present to the otolaryngologist as an orbital complication of sinus disease, or as a severe upper respiratory tract infection. The recent experience of orbital pseudotumors at our center is presented with emphasis on the diagnosis and management of the disease process.
Alteration of thiol and superoxide dismutase status in rheumatoid arthritis treated with sulphasalazine.
Intracellular thiols (LSH), superoxide dismutase (SOD) and plasma thiols (PSH) are thought to have an important role in the protection of tissues from damage by oxygen-derived free radicals. The change in the levels of activity of these substances in patients with active rheumatoid arthritis treated with sulphasalazine for 6 months was assessed in 22 patients. Over this time there was a marked improvement in disease activity. This was accompanied by an early increase in red cell LSH and decrease in SOD, although by 6 months these changes had completely reversed. In addition the negative correlation between these indices at week 0 had disappeared by week 6. Over the 6 months there was a steady rise in PSH. The change in PSH is slow and is thus more likely to reflect a change in the disease process rather than an active role for the thiol, but the early changes in intracellular parameters may be of importance in the action of this drug. These changes are similar to changes found with other second-line drugs. It is also of interest that a drug which does not itself possess a thiol group is capable of altering the thiol status of cells.
Indoor radon: a residential radiation dilemma.
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Maximum hang times for i.v. fat emulsions.
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Iodine absorption after topical administration.
Absorption from povidone-iodine preparations after topical administration has been reported to be negligible, but an elderly woman had increased serum iodine levels with possible metabolic complications after povidone-iodine solution was applied to decubitus ulcers.
Changes in glutathione in intact erythrocytes during incubation with penicillamine as detected by 1H spin-echo NMR spectroscopy.
1H spin-echo NMR spectroscopy was used to study changes in glutathione status in intact erythrocytes. The concentration of glutathione in suspensions of erythrocytes in 2H2O saline is significantly different in cells from patients with rheumatoid arthritis than in controls from normal healthy volunteers. It is observed that the methods of separation and suspension affect lactate metabolism in red cells. Incubation of erythrocytes with solutions of the therapeutic agent D-penicillamine in 2H2O saline produced a change in glutathione resonances which is indicative of an increase in diglutathione concentration. Signals from the methyl groups of penicillamine decreased at a commensurate rate. Incubation of normal cells with plasma from patients with rheumatoid arthritis who had the same blood group as the normal volunteer indicated a much larger fall in glutathione signal with plasma from a patient treated with penicillamine than from a patient on non-steroidal anti-inflammatories.