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Biomedical subjects

C E Howard

Publications and source records attributed to C E Howard.

6 recordsLinked to original sources
PubMed1997

Vancomycin-induced thrombocytopenia: a challenge and rechallenge.

OBJECTIVE: To report a case of thrombocytopenia apparently associated with vancomycin use. CASE SUMMARY: A 58-year-old white man was admitted to the hospital with chronic osteomyelitis of the foot due to methicillin-resistant Staphylococcus aureus that later spread hematogenously to the cervical vertebrae. During the first course of therapy with vancomycin, his platelet count decreased from 397 x 10(3)/mm3 to 22 x 10(3)/mm3. After discontinuation of the drug, it increased to 310 x 10(3)/mm3. During the second course of vancomycin, the platelet count decreased to 77 x 10(3)/mm3, and increased to 404 x 10(3)/mm3 after discontinuation of the drug. DISCUSSION: Vancomycin has been reported as a rare cause of thrombocytopenia. Thrombocytopenia can occur as an adverse drug reaction by the following three mechanisms: direct toxic effect, drug absorption (hapten) formation, and an "innocent bystander" immune response. CONCLUSIONS: We suspect that the thrombocytopenia in this patient, which involved an increased number of megakaryocytes in the bone marrow, was due to vancomycin.

Anti-Bacterial Agents↗
PubMed1994

Pharmacokinetics services in Department of Veterans Affairs medical centers.

The provision of pharmacokinetics services in Veterans Affairs (VA) medical centers was studied. In October 1992 a questionnaire was mailed to the chief of pharmacy at each of the nation's 160 VA medical centers. The survey was designed to determine the percentage of centers providing pharmacokinetics services, the general characteristics of pharmacokinetics services provided, and whether the presence of these services was associated with specific characteristics of the medical centers. Of the 160 questionnaires mailed, 148 (93%) were returned and analyzed. Pharmacokinetics services were provided by 104 (70%) of the respondents. Of the 104 services, 58 (56%) had existed for less than five years. Of the 44 VA medical centers without a pharmacokinetics service, almost two thirds planned to start one in the future. Aminoglycosides, vancomycin, and theophylline were the drugs most frequently monitored. Fifty-four percent of the pharmacokinetics services evaluated 1-24 patients per month, and another 24% evaluated 25-49 patients monthly. VA medical centers with a pharmacy residency program were more likely to have a pharmacokinetics service than centers without such a program; an association with geographic region was also identified. Nearly three fourths of responding VA medical centers indicated that they provided pharmacokinetics services.

Drug Monitoring↗
PubMed1994

Texture capture in Necker cubes.

Texture capture can be based on illusory contours, stereopsis, outline figures, real movement, and apparent movement. Several figures are presented that demonstrate texture capture by the use of the pictorial depth cues of the Necker cube. The textures seem affixed to the sides of the cube, follow the alternations of the cube, and extend off the picture plane. A concomitant phenomenon is a subjective rarefaction of the texture in the cube. It is suggested that boundary cues determine the assignation of texture to surfaces.

Form Perception↗
PubMed1994

Use of multiple-dose activated charcoal in phenytoin toxicity.

OBJECTIVE: To report a case of phenytoin toxicity successfully treated with multiple-dose activated charcoal. CASE SUMMARY: A 36-year-old man was first admitted with chronic phenytoin toxicity secondary to hepatitis and was treated symptomatically. His serum phenytoin concentration was 149.8 mumol/L on admission and decreased slowly over his 6-day hospitalization to 134.8 mumol/L. Upon readmission approximately 24 hours later, his phenytoin concentration was 186.7 mumol/L. Because of acute phenytoin toxicity, he was treated with multiple-dose activated charcoal. His phenytoin concentration after four doses of activated charcoal returned to the therapeutic range within 36 hours and his symptoms abated quickly, thus decreasing his hospital stay. DISCUSSION: The exact mechanism of action of multiple-dose activated charcoal to decrease serum phenytoin concentrations is unknown. Several mechanisms of action have been reported in the literature and are discussed. CONCLUSIONS: Multiple-dose activated charcoal was used successfully in treating acute phenytoin toxicity in our patient. Based on his previous admission for chronic phenytoin toxicity, his hospital stay was reduced by three days. The use of multiple-dose activated charcoal in acute phenytoin toxicity has potential therapeutic and financial implications.

Adult↗