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Biomedical subjects

R Sawyer

Publications and source records attributed to R Sawyer.

At least 19 recordsLinked to original sources
PubMed1992

A phase II trial of biochemical modulation using N-phosphonacetyl-L-aspartate, high-dose methotrexate, high-dose 5-fluorouracil, and leucovorin in patients with adenocarcinoma of unknown primary site.

BACKGROUND: 5-Fluorouracil (5-FU) has modest activity as a single agent in a number of human adenocarcinomas. The technique of biochemical modulation has been used preclinically to increase the activity of 5-FU. METHODS: With doses based on a Phase I study, the authors performed a Phase II trial in patients with advanced metastatic adenocarcinoma of an unknown primary site using N-phosphonacetyl-l-aspartate (PALA), methotrexate (MTX), 5-FU, and leucovorin. In some patients, 5-phosphoriosyl-l-pyrophosphate (PRPP) and uridine triphosphate (UTP) metabolite pools were assayed before and after PALA and MTX to assess metabolite pool shifts. RESULTS: Twenty-one patients were treated in this Phase II trial. Toxicity was tolerable. Biopsy specimens of tumor tissue showed increases in PRPP and decreases in UTP levels in two of three and three of four patients, respectively. However, only one objective response was seen, which is not different from that expected with 5-FU alone. CONCLUSIONS: Expected PRPP and UTP metabolite pool shifts were seen when biochemical modulation was performed with these drugs according to this schedule. Because toxicity was mild, more intense dose schedules of 5-FU are planned for future studies.

Adenocarcinoma↗
PubMed1990

Metronidazole in head and neck surgery--the effect of lengthened prophylaxis.

Previous studies of antibiotic prophylaxis have shown that treatment for 24 hours has been beneficial for head and neck surgery and that longer periods of antibiotic therapy have not improved results. Metronidazole (Flagyl), unlike other antibiotics tested, has been shown to be effective in an experimental abscess, even if treatment is begun up to 120 hours after administration of inoculum. This article presents a prospective, randomized, multifactorial study comparing a brief vs. a prolonged duration of metronidazole and cefazolin prophylaxis in 50 consecutive patients with a head and neck cancer undergoing operation. Patients receiving 2 days vs. 7 or more days of antibiotic prophylaxis were compared. Statistical analysis of data demonstrated a striking reduction in severity of wound complications and a reduced incidence of wound infections in the group treated with 7 or more days of antibiotic prophylaxis.

Adult↗
PubMed1989

Achieving high quality in slide production for medical education.

We have found several simple photographic techniques to be helpful in preparing our own near-professional teaching slides. Effective use of different brands of photographic materials is possible, but we present only the ones with which we are most familiar and which we have found simple, economical, and reliable. Slides can be produced in less than 24 hours using the methods presented.

Audiovisual Aids↗
PubMed1989

Delayed side effects of droperidol after ambulatory general anesthesia.

The incidence of postoperative effects of droperidol, in the hospital and at home the following night, after general anesthesia for minor outpatient procedures was evaluated in two groups of 50 patients each. Anesthetic techniques were identical except for the presence or absence of 1.25 mg of IV droperidol. There were no differences between the groups with regard to postoperative nausea, vomiting, pain, or time to discharge. In 23% of patients given droperidol, anxiety or restlessness developed after discharge from the ambulatory care unit. No patient not receiving droperidol had these reactions. It is suggested that the routine use of droperidol in all outpatients receiving general anesthesia may not be appropriate.

Adult↗
PubMed1989

Effects of extracellular matrix on cytoskeletal and myofibrillar organization in vitro.

The distribution and three-dimensional relationship of myofibrillar and cytoskeletal components during myofibrillogenesis were examined in preparations of neonatal rat cardiac myocytes processed in parallel for scanning electron microscopy (SEM), intermediate voltage transmission electron microscopy (IVEM) and immunofluorescence (IF). Of the various methods used for processing, optimal results were achieved by pre-extraction with Triton X-100 in an actin-stabilizing buffer. This procedure effectively removed the surface membrane, as viewed by SEM images, while preserving myofibrillar and cytoskeletal structure, as evidenced by IF for actin, alpha-actinin and vinculin. Cytoskeletons in SEM images consisted of a cortex of anastomosing filaments through which ran parallel filament bundles oriented in the long axis of the cell and attached along their length to the substrate by numerous fine filaments. In IVEM images, myofibrils were laterally connected at the level of the Z bands. Myocytes grown on different extracellular matrices showed different patterns and distributions of both striated myofibrils and focal adhesions, as determined by IF for alpha-actinin and vinculin, respectively. Cells on collagen I and III contained striated myofibrils which extended to the cell perimeters where focal adhesions were predominately located. Cells on laminin and fibronectin matrices exhibited myofibrils and focal adhesions more centrally located. In addition, cells on laminin contained circumferential arcs of filaments near the cell periphery.

Animals↗
PubMed1989

Facial presentation of disseminated superficial actinic porokeratosis.

A case of disseminated superficial actinic porokeratosis (DSAP), an autosomal dominant genodermatosis possessing a pathognomonic cornoid lamella, is presented. Exclusively facial disseminated superficial actinic porokeratosis is an unusual clinical presentation, although 15% of patients having the condition in the typical generalized form have facial lesions. There is no specific treatment. In selected cases, lesions may be excised, electrodesiccated, or sprayed with liquid nitrogen. Topical steroids and topical 5-fluorouracil have been reported to be beneficial in some instances. Sunscreens should be tried as a preventive measure, especially in family members of patients with known DSAP.

Adult↗
PubMed1987

Reduction with age in the relaxation to beta-adrenoceptor agonists and other vasodilators in rat aorta.

We have examined the relaxation produced by the beta-adrenoceptor agonists isoprenaline and procaterol, and by sodium nitroprusside, forskolin and isobutylmethylxanthine in KCl (40 mmol/l)-contracted aortae from 6 week, 3 month and 6 month old Sprague-Dawley rats. The maximum relaxation to all agents was greatest in aortae from 6 week old animals. The relaxation to the beta-adrenoceptor agonists was virtually abolished, and the relaxation to the other agents significantly reduced, in aortae from 3 and 6 month old animals. There were no significant differences in the response to any agent between aortae from 3 and 6 month old animals, so that the changes seen occurred in maturation from 6 week to 3 month. The reduced vasodilator response does not occur at the level of the beta-adrenoceptor or adenylate cyclase, since the response to sodium nitroprusside was also affected, but is a general reduction in the ability of the aorta to relax.

Adrenergic beta-Agonists↗
PubMed1987

Unusual head and neck manifestations of non-Hodgkin's lymphomas in children and adults.

Certain patterns of "lymphoma masquerade" are examined, where the diagnosis is very difficult to establish. The presence of prolonged symptoms prior to the acute event or indolent slow healing wounds should alert clinicians to the possibility that lymphoma may be involved. Localizing tumors in order to make a tissue diagnosis is one potential problem encountered even with computerized tomography, but magnetic resonance imaging has been helpful in demonstrating the presence of tumor mass. Included in this report is an unusual series of non-Hodgkin's lymphoma cases in which there was not an obvious tumor. Three patients presented with symptoms and findings of deep neck abscess, two of which were associated with an esophageal perforation or tracheoesophageal fistula. The other cases involved chronic sinusitis and an apparent viral polyneuropathy affecting multiple cranial nerves. Treatment of these non-Hodgkin's lymphomas and techniques for establishing the pathological diagnosis are discussed.

Abscess↗
PubMed1986

Direct cardiac actions of phenylephrine when used in assessment of baroreflex function in the rat.

In pentobarbitone-anaesthetised wistar rats, the baroreflex bradycardia in response to the vasopressor agent phenylephrine was converted to a tachycardia by propranolol. In pithed wistar rats, phenylephrine produced a marked tachycardia which was mediated largely by beta-adrenoreceptors since propranolol markedly antagonised the response. A component of the tachycardia was mediated by alpha 1-adrenoreceptors since the tachycardia to phenylephrine in the presence of propranolol was antagonised by prazosin and mimicked by the alpha 1-adrenoreceptor agonist amidephrine. It is concluded that phenylephrine is not a useful agent for assessment of baroreflex function in the rat due to its marked cardiac stimulant actions.

Animals↗
PubMed1986

Sialadenoma papilliferum of the adenoids in a 2-year-old child.

We report a case of sialadenoma papilliferum arising in the adenoids in a 2-year-old child. The tumor demonstrated papillary and adenomatous proliferations, suggestive of minor salivary gland origin. A review of the literature indicated no reported cases of this neoplasm arising in individuals this young. The location of the growth also appears to be unique. Regular follow-up by endoscopy and computed tomographic scan of the nasopharyngeal area have not revealed recurrence of disease one year after resection.

Adenoids↗
PubMed1985

Treatment of upper esophageal strictures.

A practical approach to the treatment of upper esophageal and hypopharyngeal strictures is presented. Traditional dilation techniques and instrumentation are reviewed. The size and shape of the stricture are related to the risks of using certain types and sizes of bougies. The adjunctive use of fluoroscopy, urethral dilators, and arteriography materials for esophageal dilation is discussed in light of the dilation treatment option.

Angiography↗