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Biomedical subjects

D K Armstrong

Publications and source records attributed to D K Armstrong.

72 records · Page 4Linked to original sources
PubMed1991

In vitro and in vivo studies with sodium hyaluronate as a carrier for intraocular gentamicin.

We compared the in vitro growth of common intraocular pathogens Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa in rabbit vitreous and in sodium hyaluronate (SH) with and without gentamicin. The minimal inhibitory concentration for gentamicin/SH was 0.5, 0.062 and 2.0 mcg/ml for these pathogens, respectively. After posterior capsulotomy, P. aeruginosa was inoculated into the anterior vitreous and all 15 untreated eyes developed endophthalmitis. In a similar group, aqueous gentamicin administered in the anterior chamber reduced the incidence of endophthalmitis to 10 of 15 eyes. Under similar circumstances, the SH/gentamicin combination lowered the incidence of endophthalmitis significantly to 4 of 15 eyes. The half-life of aqueous gentamicin was 0.9 h, which was shorter than the 2.2 h for SH/gentamicin combination. These results suggest that SH may be a useful carrier for intraocular drug therapy.

Animals↗
PubMed1989

Taxol: a unique antineoplastic agent with significant activity in advanced ovarian epithelial neoplasms.

STUDY OBJECTIVE: To assess the activity of taxol in patients with advanced, progressive, and drug-refractory ovarian cancer and to delineate more clearly the toxicity of taxol in this patient population. DESIGN: Nonrandomized, prospective phase II trial. PATIENTS: Forty-seven patients with drug-refractory epithelial ovarian cancer who had one or more lesions measurable in perpendicular diameters. Of these patients, 45 were evaluable for toxicity and 40 were evaluable for response. INTERVENTIONS: PATIENTS were treated every 22 days with varying doses of taxol (110 to 250 mg/m2 body surface) given as a 24-hour infusion with subsequent doses based on adverse effects. A premedication regimen was used to avoid acute hypersensitivity reactions. MEASUREMENTS AND MAIN RESULTS: Twelve patients (30%; CI, 16% to 44%) responded to taxol for periods lasting from 3 to 15 months. The dose-limiting toxicity was myelosuppression with leukocytes affected more severely and commonly than thrombocytes or reticulocytes. Leukopenia was usually brief in duration but was associated with sepsis in 3 cases (2 fatal). Other adverse effects included myalgias, arthralgias, alopecia, diarrhea, nausea, vomiting, mucositis, and peripheral neuropathy. Rare cases of cardiac and central neurotoxicity were also noted. CONCLUSIONS: Taxol is an active agent in drug-refractory ovarian cancer and deserves further study in combination with other active drugs in previously untreated patients with advanced ovarian cancer.

Alkaloids↗
PubMed1988

Variability in aminoglycoside pharmacokinetics in critically ill surgical patients.

The pharmacokinetics of the aminoglycosides were evaluated in 181 patients admitted to a surgical ICU. Pharmacokinetic parameters changed from 16% to 40% during therapy requiring multiple dosage adjustments and nearly nine drug levels per patient. Dosage adjustments resulted in peak and trough serum concentrations within the therapeutic range 71% and 74% of the time. Aminoglycoside half-life (T1/2) ranged from 1.1 to 69.3 h. Aminoglycoside volume of distribution also varied considerably with an average value of 0.36 L/kg. During therapy most patients gained weight (average 8.4 kg) which correlated with their corresponding fluid gain of 11.6 L. Pharmacokinetic parameters were variable even in patients with a normal serum creatinine. Less than 50% of these patients received the recommended daily dosages. This study suggests that the aminoglycoside volume of distribution in critically ill surgical patients differs from general hospital patients and pharmacokinetic parameters change considerably during therapy. We recommend obtaining timed serum aminoglycoside concentrations early in therapy and adjusting drug dosages as needed to maintain serum concentrations in the therapeutic range.

Adult↗
PubMed1988

Hemodialysis of amikacin in critically ill patients.

The clearance of amikacin during hemodialysis (HD) was determined in eight critically ill patients. The dialysis period averaged 3.4 h with a blood flow of 200 ml/min. The average amikacin clearance between dialysis was 7.30 +/- 4.78 (SD) ml/min which increased to 37.5 +/- 8.01 ml/min during dialysis. The average serum amikacin concentration before dialysis fell 27% after dialysis. The fraction of drug in the body removed only from dialysis averaged 21%. Although amikacin was cleared more effectively during HD compared to the interdialysis period, the small amount of drug removed suggests that routine supplemental dosing of amikacin after HD may not be necessary.

Adult↗
PubMed1988

Clinical response and total and unbound plasma concentrations after lidocaine overdose.

Plasma and unbound concentrations and hemodynamic and CNS effects were monitored in a patient after overdose of 2 g of lidocaine HCl infused during 1 h. Hypotension, decreased heart rate, tremors, and nonresponsiveness to stimuli were observed at plasma and unbound concentrations of 17.7 and 12.0 micrograms/ml. The half-lives of decline of plasma and unbound concentrations were 3.8 and 2.7 h; the difference in half-lives was due to nonlinear plasma protein binding.

Aged↗
PubMed1988

Pharmacoeconomic impact of critically ill surgical patients.

Financial information on 131 patients and drug-related information on 176 patients admitted to a surgical intensive care unit (ICU) were prospectively collected. The average stay was nearly five days and patients received 8.6 drugs per day for a total average exposure of 12.2 different drugs. Antibiotics and analgesics were used in over 90 percent of patients. The patients' diagnoses fit into 53 different diagnosis-related groups (DRG). Hospital costs were significantly greater than DRG payment for an average revenue loss of $17,803 per patient. Patients with a primary diagnosis of sepsis had the largest revenue loss, averaging $54,738. One hundred patients were revenue losers. Total hospital stay was statistically longer than DRG-projected length of stay. Pharmacy charges averaged 13.6 percent of total hospital charges. Patients receiving systemic antifungals, triple antibiotics, catecholamines, and total parenteral nutrition had high hospital and pharmacy costs. This study suggests that ICU patients are costly to hospitals and that drug use is expensive. We suggest that increased pharmacy involvement in the care of ICU patients may help curtail escalating drug costs in these patients.

Critical Care↗
PubMed1986

Effect of low-dose dopamine on the pharmacokinetics of tobramycin in dogs.

Low-dose dopamine or a placebo was given to six healthy mongrel dogs, each receiving tobramycin at 2.0 mg/kg on consecutive days in a randomized crossover fashion. Dopamine increased the total and renal clearances and elimination rate constant of tobramycin by 12.5, 20, and 25.9%, respectively, suggesting that low-dose dopamine increases the clearance of tobramycin in dogs primarily through renal mechanisms.

Animals↗
PubMed1984

Ampicillin-associated seizures.

Two patients had ampicillin-associated seizures. Although they had complex medical problems, the high serum concentrations of ampicillin at the time of seizures without their recurrence after discontinuing the antibiotic suggest that the seizures were related to the ampicillin therapy.

Adult↗
PubMedDate not supplied

BRCA1 expression in a large series of sporadic ovarian carcinomas: a Gynecologic Oncology Group study.

BRCA1 is a tumor suppressor gene that, when mutated, is associated with the development of hereditary ovarian cancer. A role for BRCA1 in the pathoetiology of sporadic ovarian epithelial cancer (OEC) development has been suggested, although spontaneous mutations of the BRCA1 gene in this disease are uncommon. Loss of gene function by epigenetic alteration is observed more commonly, while other means of gene inactivation have not been intensively investigated. We examined expression and localization of the BRCA1 gene product by immunohistochemistry and sought to clarify the relationship between protein expression and tumor stage, grade, histopathologic subtype, and outcome. Among 230 spontaneous OEC tumors, we found a statistically significant decrease in BRCA1 protein expression with advancing stages of OEC. There was no relationship between expression and tumor grade. There was a statistically significant relationship between the pathologic subtypes of OEC and BRCA1 expression. Minimal BRCA1 expression was protective for survival. These findings confirm a high rate of loss of BRCA1 protein expression in sporadic OEC and suggest a role of BRCA1 in the progression of sporadic ovarian carcinoma.

BRCA1 Protein↗
PubMedDate not supplied

Congenital triangular alopecia.

We report a child with bilateral congenital triangular alopecia. Shaving the scalp and inserting intravenous cannulas into scalp vessels during the neonatal period was misconstrued by the parents as the cause of hair loss, and resulted in medicolegal implications.

Alopecia↗
PubMedDate not supplied

Autosomal recessive inheritance of erythrokeratoderma variabilis.

Erythrokeratoderma variabilis is a rare genodermatosis conventionally regarded as autosomal dominant in inheritance. We describe the clinical features and light and electron microscopic findings in two affected siblings born to unaffected parents and suggest an autosomal recessive mode of inheritance in this family. We also briefly review the literature on this disorder.

Erythema↗
PubMedDate not supplied

Intracavernosal papaverine and phentolamine for the medical management of erectile dysfunction in a genitourinary clinic.

A total of 160 men with erectile failure received treatment with 13,030 intracavernosal papaverine and phentolamine injections as outpatients. One-hundred-and-fifteen (72%) achieved an erection sufficient for sexual intercourse and after a mean follow-up period of 14.1 months, 55 (48%) are still attending and successfully using intracavernous therapy. Sixteen patients had a total of 22 episodes of priapism and one patient developed corporeal fibrosis. We conclude that intracavernous papaverine and phentolamine is an effective therapy for erectile failure in a genitourinary clinic.

Adult↗
PubMedDate not supplied

Effect of haloperidol on dopamine-induced increase in renal blood flow.

Increasing renal blood flow (RBF) by the administration of low-dose dopamine is one mechanism to increase urine output in oliguric patients. This response is mediated in part by stimulation of dopaminergic receptors in the kidney, which could be attenuated by the dopamine blocker haloperidol. We evaluated this interaction by administering both drugs in clinically used doses to six anesthetized mongrel dogs. A dopamine regimen of 2.5 micrograms/kg/min significantly increased RBF along with cardiac output and stroke volume. Simultaneous administration of haloperidol 50 micrograms/kg iv did not influence the ability of low-dose dopamine to increase RBF. Although haloperidol is an antagonist of dopaminergic receptors, the increase in RBF associated with low-dose dopamine is maintained when intravenous haloperidol is concurrently administered to dogs.

Animals↗