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Biomedical subjects

L W Brown

Publications and source records attributed to L W Brown.

At least 37 records · Page 2Linked to original sources
PubMed1980

Comparison of two high-pressure liquid chromatographic assays for carboprost, a synthetic prostaglandin.

A high-pressure liquid chromatographic assay for carboprost tromethamine as the bulk drug and in a sterile solution formulation is described. The procedure involves derivatization of the prostaglandin to form the UV-absorbing naphthacyl ester, which then is chromatographed on a silica gel column using methylene chloride-1,3-butanediol-water (496:4:0.25) as the mobile phase. This procedure is compared with a nonderivatization procedure with refractive index detection. Both procedures separate the 15R-epimer of carboprost from carboprost, but only the derivatization procedure separates the 5-trans-isomer of carboprost. Possible reasons for the better separation using the derivatization procedure are discussed. Both procedures gave a coefficient of variation of approximately 1% for carboprost. The derivatization procedure gave a coefficient of variation of approximately 7% for the 15R-epimer and 5-trans-isomer when present at 2% of the carboprost level.

Carboprost↗
PubMed1979

Infant botulism.

Infant botulism is a unique neuromuscular disease affecting infants less than six months old. It is the result of intraintestinal toxin production by C. botulinum (toxi-infection). Characteristic symptoms include constipation, lethargy, and decreased feeding. Physical examination often reveals generalized hypotonia with cranial nerve impairment. Recovery is dependent on supportive care in an intensive care setting. The relationship of this disease to the sudden infant death syndrome requires further study.

Botulinum Antitoxin↗
PubMed1978

High-pressure liquid chromatographic determination of cycloheximide in ointment and suspension formulations.

A high-pressure liquid chromatographic procedure is described for the assay of the antibiotic cycloheximidein bulk drug and two experimental formulations. The method utilizes a reversed-phase C18 chromatographic column and refractive index detection. Possible impurities or degradation products, isocycloheximide, anhydrocycloheximide, and dimethylcyclohexone, are well separated from cycloheximide by this procedure. Complete extraction of cycloheximide from the formulations was obtained. The assay has a relative standard deviation of approximately 1%.

Chromatography, High Pressure Liquid↗
PubMed1978

High-pressure liquid chromatographic assays for clindamycin, clindamycin phosphate, and clindamycin palmitate.

High-pressure liquid chromatographic procedures are described for clindamycin, clindamycin palmitate, and clindamycin phosphate as bulk drugs and in formulations. All three procedures utilize a C18 reversed-phase chromatographic column with refractive index detection. The mobile phases are hydroalcoholic solutions containing dioctyl sodium sulfosuccinate or disodium ethylenediaminetetraacetate. Separations of related impurities or degradation products also are discussed. The relative standard deviations of the methods range from 0.8 to 1.8%.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Wooden transnasal intracranial penetration: an unusual presentation.

A 2 1/2-year-old child presented to the emergency department with a wooden stick lodged firmly in her right nares. No nasal discharge or neurological abnormalities were noted at presentation. After plain radiographs failed to demonstrate any evidence of a foreign body, computed tomography (CT scan) was obtained that revealed a hypodense region in the right frontal lobe corresponding to the projected tract of the branch. The patient underwent a right frontal craniotomy with debridement of her contused right frontal lobe. She was discharged 8 days postoperatively without evidence of neurologic sequelae. This case illustrates an unusual presentation of intracranial penetration, with only six similar cases found in the literature. It also highlights the need for the emergency physician to be concerned about intracranial penetration when treating intranasal foreign bodies, particularly those of the nonmetallic type. The literature is reviewed regarding transnasal intracranial penetration by wooden foreign bodies.

Child, Preschool↗
PubMedDate not supplied

Hypoxemia and hemodynamic changes during the hypercarbia stimulation test.

The hypercarbia stimulation test is a valuable technique to document the absence of brainstem responsiveness to elevated levels of carbon dioxide (PCO2); however, its application has been limited by concern that hypoxemia may induce cardiovascular instability. We investigated hemodynamic and oxygen (PO2) changes in 19 patients: group 1 (17 patients) had no spontaneous ventilations at PCO2 values ranging from 37-129 torr; group 2 (2 patients) had spontaneous ventilations at less than 38 torr. Group 1 was separated into 2 subgroups: A (10 patients) with PO2 greater than 153 torr and B (7 patients) with PO2 less than 80 torr. Hemodynamic changes (less than 10% variation in baseline pulse and blood pressure) occurred in 9 of 10 patients in group 1A and all patients in Group 1B. Mean differences in pulse and blood pressure changes between these groups were not significant; therefore, pulse and blood pressure changes are not predictive of hypoxemia and hypercarbia is not necessary to induce spontaneous ventilation in patients with intact medullary function.

Adolescent↗