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Biomedical subjects

A Chin

Publications and source records attributed to A Chin.

At least 55 records · Page 3Linked to original sources
PubMed1991

Utility of a transdermal delivery system for antihypertensive therapy. Part 1.

A retrospective evaluation of patient-level Medicaid claims data from two states was undertaken to discern the fiscal utility of transdermally delivered clonidine versus both the oral formulation of clonidine and oral formulations of eight other antihypertensive agents. In the first phase of our two-part study, we compared paid claims data (n = 1,135) from Florida for transdermal and oral clonidine. Multivariate regression analysis was used to evaluate the incremental impact of six variables on health-care expenditures in the first year after patients were given a diagnosis of hypertension. These variables were: age, gender, prior utilization of medical services, regimen complexity, and dosage formulation. Patients prescribed transdermal clonidine experienced a significant (p less than or equal to 0.001) increase in prescription expenditures and significant reductions in the use of physician (p less than or equal to 0.05), laboratory (p less than or equal to 0.10), and hospital (p less than or equal to 0.05) services. Moreover, savings were maximized (p less than or equal to 0.001) where multi-drug regimens incorporated the transdermal delivery system. In the second phase of our study we compared paid claims data (n = 8,894) from South Carolina for transdermal clonidine and for nine oral antihypertensive agents: atenolol, captopril, clonidine, diltiazem, enalapril, metoprolol, prazosin, terazosin, and verapamil-SR. Once again, regression analysis was used, this time to evaluate the incremental impact of five variables on health-care expenditures in the first year post diagnosis: age, gender, prior utilization of medical services, regimen complexity, and Medication Possession Ratio (MPR), an index of compliance. The data from part 2 of our study revealed that patients assigned a b.i.d. oral antihypertensive agent experienced a significant reduction (p less than or equal to 0.05) in MPR and a significant (p less than 0.05) increase in health-care expenditures when compared to patients prescribed the transdermal delivery system and to patients prescribed once-daily oral medications. These data confirm previous findings concerning the impact of complicated dosing regimens on compliance in hypertensive patients. In this two-part paper we report the data from both phases of our study.

Administration, Cutaneous↗
PubMed1991

Chelation of divalent cations by ATP, studied by titration calorimetry.

Thermodynamic parameters and stoichiometry for the formation of complexes of ATP with Mg2+, Ca2+, and Sr2+ were determined by titration calorimetry. In each case, 1:1 stoichiometry was observed and complex formation was entropy driven. Binding constants for formation of complexes decreased in the order of Mg2+ greater than Ca2+ greater than Sr2+, as expected from charge density considerations. Monovalent cations hindered complex formation with Mg2+, apparently by competing with the divalent cation for complexation with ATP. Analysis of this competitive effect provided estimates of the binding constants for complexes of ATP with monovalent cations, which decreased in the order expected from charge density considerations (Li+ greater than Na+ greater than K+).

Adenosine Triphosphate↗
PubMed1991

Analysis of cefepime tissue penetration into human appendix.

Cefepime is a new extended-spectrum cephalosporin with gram-positive and gram-negative coverage including Staphylococcus aureus and Pseudomonas aeruginosa. We evaluated the drug's plasma, peritoneal fluid, and appendix tissue concentrations in patients with a postoperative diagnosis of perforated or gangrenous appendicitis. Patients 18 years of age or older were randomly assigned to receive either cefepime 2 g every 12 hours plus metronidazole 500 mg every 6 hours intravenously, or gentamicin 1.5 mg/kg plus clindamycin 900 mg every 8 hours intravenously. During surgery, appendix tissue, plasma, and peritoneal fluid samples were obtained, and frozen at -70 degrees C for high-pressure liquid chromatographic analysis. Thirty-five patients with perforated (26) or gangrenous (9) appendicitis had concentrations acceptable for analysis. The mean time between the administration of cefepime and the time of sampling (referred to as delta time) was 5.99 +/- 3.75 hours (mean +/- SD). The values for plasma (n = 34), tissue (n = 33), and peritoneal fluid (n = 25) concentrations were 16.27 +/- 21.87 micrograms/ml, 4.84 +/- 6.15 micrograms/g, and 14.4 +/- 22.84 micrograms/ml, respectively. The appendix tissue:plasma ratio was 0.66 +/- 0.52 and the peritoneal fluid:plasma ratio was 0.66 +/- 0.51. Spearman rank correlations indicated statistically significant correlations between plasma concentration (r = -0.889; p less than 0.0001), peritoneal fluid concentration (r = -0.783; p = 0.0002), and appendix tissue concentration (r = -0.704; p = 0.0016) versus delta time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Radiation sickness; prospective study of incidence and course].

In a prospective inventory analysis of 169 irradiated patients concerning the incidence and course of Acute Radiation Sickness (fatigue, loss of appetite, nausea and vomiting), it was found that 2/3 of the patients had these complaints. The complaints started during the first week of treatment and mostly even within a few hours after each radiotherapy session. All complaints were progressive during the radiotherapy course, but disappeared spontaneously within one week after completion of the treatment. The possible occurrence of these symptoms soon after the start of radiotherapy should be kept in mind, especially since they can be reduced by simple regimens.

Adult↗
PubMed1990

Techniques applied for total body irradiation.

In this review, different techniques of total body irradiation are discussed with special attention to their advantages and disadvantages. The results of an EBMT questionnaire, which was sent out to the European TBI centres, are also presented. It turned out that there exists a great variety in techniques, total doses, and fractionation schedules used all over Europe. It was also clear that the documentation concerning dosimetry and the time factor in TBI still has some deficiencies. Therefore, a proposal is now made for reporting the technical and dosimetric aspects used in total body irradiation in an unambiguous manner.

Humans↗
PubMed1990

Intraoperative concentrations of ofloxacin in serum, bile fluid, and gallbladder wall tissue.

To evaluate concentrations of ofloxacin in serum, bile fluid, and gallbladder wall tissue after intravenous administration, patients greater than or equal to 16 years old diagnosed with acute cholecystitis were randomly assigned to receive ofloxacin (400 mg) intravenously every 12 h or ceftazidime (2 g) intravenously every 8 h. Doses of each regimen were given preoperatively. Serum, bile fluid, and gallbladder wall tissue samples of consecutive patients in the ofloxacin group were obtained intraoperatively. The samples were frozen at -70 degrees C until analyzed by high-pressure liquid chromatography. Twenty-three patients (6 males and 17 females) were evaluated. The mean (+/- the standard deviation) ofloxacin concentrations in serum, bile fluid, and gallbladder wall tissue were 2.9 +/- 2.4 and 6.0 +/- 7.9 micrograms/ml and 3.1 +/- 2.9 micrograms/g, respectively. The mean number of doses each patient received before surgery was 5.3 +/- 3.0, and the mean delta time (time elapsed between last antibiotic administration and when intraoperative samples were obtained) was 9.6 +/- 7.5 h. The mean tissue-to-serum ratio was 1.2 +/- 0.5, and the mean bile-to-serum ratio was 2.3 +/- 1.4. The mean serum ofloxacin concentrations were not statistically different from the concentrations in bile (P = 0.1) and tissue (P = 0.7) at the mean delta time. The study revealed that concentrations of ofloxacin in serum, bile fluid, and gallbladder tissue after intravenous dosing were adequate against susceptible organisms found in the biliary tract.

Adult↗
PubMed1990

Treatment of intra-abdominal infections: cost comparison of ampicillin/sulbactam and clindamycin/gentamicin.

The cost of 2 g ampicillin/1 g sulbactam given IV piggyback qid was compared with 900 mg clindamycin admixed with 1.5 mg/kg gentamicin given IV piggyback tid for the treatment of perforated or gangrenous appendicitis in 116 patients. Fifty-eight ampicillin/sulbactam-receiving patients incurred greater costs for IV supplies (+104.6/patient vs +67.9/patient) and nursing administration costs (+16.5/patient vs +10.7/patient). On the other hand, pharmacist and technician preparation costs were greater for the 58 clindamycin/gentamicin-receiving patients (+15.4/patient vs +13.3/patient). The clindamycin/gentamicin-receiving patients also incurred additional changes for laboratory fees and pharmacokinetic monitoring--+18.7/patient and +36.1/patient, respectively. When incorporating all cost parameters, there were no statistically significant differences in mean total drug therapy costs between the two treatment regimens--+433.3 +/- +58.5/patient for ampicillin/sulbactam and +373.8 +/- +86.2/patient for clindamycin/gentamicin.

Ampicillin↗
PubMed1989

Cost analysis of two clindamycin dosing regimens.

A clinical trial of clindamycin 900 mg q8h admixed with gentamicin 1.5 mg/kg (eight-hourly group) versus clindamycin 600 mg q6h with gentamicin 1.5 mg/kg given separately (six-hourly group) was analyzed for relative cost containment. Acquisition costs were significantly higher for the six-hourly group for intravenous supplies ($181.5 +/- 47.8) when compared with the eight-hourly group ($67.6 +/- 21.6) (p less than 0.05). Nursing administration costs were greater for the six-hourly group ($28.6 +/- 7.5) compared with ($10.7 +/- 3.4) for the eight-hourly group (p less than 0.05). Also, significantly higher cost (p less than 0.05) was noted for pharmacist and technician manufacturing cost for the six-hourly group ($15.4 +/- 4.0) compared with the eight-hourly group ($13.3 +/- 4.3). Incorporating all appropriate costs, the mean total drug therapy costs were significantly greater (p less than 0.05) for clindamycin 600 mg q6h ($527.4 +/- 143.0) compared with clindamycin 900 mg q8h ($433.3 +/- 99.2). The dosing of clindamycin 900 mg q8h admixed with gentamicin 1.5 mg/kg is a more cost-effective method of drug delivery with similar efficacy and safety when compared with clindamycin 600 mg q6h with gentamicin given separately.

California↗
PubMed1989

A cost comparison of intramuscular versus intravenous imipenem.

Previously reported clinical trials of imipenem-cilastatin 500 mg given intravenously every 6 hours (intravenous group) and imipenem-cilastatin 750 mg given intramuscularly every 12 hours (intramuscular group) were analyzed for relative cost savings. Acquisition costs were significantly higher for the intravenous group for intravenous supplies (30.6 +/- 7.9 dollars) when compared to the intramuscular group (0.98 +/- 0.03 dollars) (p less than 0.05). Also, significantly higher cost (p less than 0.05) was noted for salaries of pharmacists and technicians for manufacturing in the intravenous group (5.8 +/- 1.5 dollars) as compared to the intramuscular group (2.4 +/- 0.7 dollars). Nursing administration costs were greater for the intramuscular group (15.6 +/- 4.8 dollars) when compared to the intravenous group (11.7 +/- 3.0 dollars). Incorporating all appropriate costs, the mean total drug therapy costs (TRX$) were significantly greater (p less than 0.01) for the intravenous group (458.17 +/- 175.17 dollars) as compared to the intramuscular group (298.0 +/- 114.76 dollars). Thus, the dosing of imipenem-cilastatin 750 mg intramuscularly every 12 hours is a more cost effective method of drug delivery with equal efficacy and safety when compared to imipenem-cilastatin 500 mg given intravenously every 6 hours.

Adolescent↗
PubMed1989

Evaluation of two different dosage regimens of clindamycin and the penetration into human appendix.

The study objective was to evaluate serum, peritoneal fluid, and appendix tissue concentrations of clindamycin using two differing clindamycin regimens. Patients age 16 years and older who were about to undergo appendectomies were randomly assigned to receive gentamicin 1.5 mg/kg every 8 h admixed with clindamycin 900 mg every 8 h (8-h group) or clindamycin 600 mg every 6 h given separately (6-h group). Doses of each regimen were given preoperatively. Serum, peritoneal fluid, and appendix tissue samples were obtained intraoperatively, and frozen at -70 degrees C for gas chromatographic drug analysis. Twenty-one patients were evaluated, 11 patients in the 8-h group and 10 patients in the 6-h group. Values are reported as means +/- standard deviations. The values in the 8-h group were 12.3 +/- 14.1 micrograms/ml, 8.7 +/- 3.9 micrograms/ml, and 9.8 +/- 10.3 micrograms/g for serum, peritoneal fluid, and appendix tissue, respectively. The values in the 6-h group were 9.7 +/- 5.1 micrograms/ml, 5.8 +/- 5.3 micrograms/ml, and 6.2 +/- 4.9 micrograms/g for serum, peritoneal fluid, and appendix tissue, respectively. The 6-h group received more doses preoperatively (1.8 +/- 0.6) than the 8-h group (1.2 +/- 0.4; p less than 0.05). No differences in penetration of clindamycin into the serum, peritoneal fluid, and appendix tissue for the 8-h group and the 6-h group were noted. The study revealed a similarity in penetration of clindamycin into the serum, peritoneal fluid, and appendix tissue using either clindamycin 900 mg given by intermittent intravenous infusion every 8 h admixed with gentamicin or clindamycin 600 mg given every 6-h separately.

Adolescent↗
PubMed1988

Circadian feeding and drinking patterns of genetically obese mice fed solid chow diet.

Feeding and drinking were recorded in male ob/ob mice and lean mice fed pelleted Purina Lab Chow No. 5001 with water to drink. The circadian patterns of eating and drinking of obese mice differed from those of lean mice, in both the proportional temporal distributions of feeding and of drinking behavior across the 24-hour day and in the absolute amounts consumed hourly. The pattern of increased food consumption by the obese mice was different than that underlying increased water consumption. When meal parameters were analyzed in terms of 'complete meals' of both feeding and drinking (the end of a meal defined as at least 12 consecutive minutes with no ingestion), obese and lean mice had the same number of meals and their periodicity was similar, but meal size was much greater in the obese mice. In the dark, both obese and lean mice showed strong postprandial correlations of meal size with time from the start of a meal to start of the next meal.

Animals↗
PubMed1988

Toward an analogue of alcoholism in mice: analysis of nongenetic variance in consumption of alcohol.

Drinking behavior of the isogenic mouse strain C57BL/6J was analyzed into nongenetic components: stochastic fluctuations, responses to fluctuations in the current environment, and persistent differences between individual animals. The latter accounted for the major part of the variance. The variance was neither increased by differences in diet during the postweaning rapid growth period (prior to assay for drinking choice) nor diminished by uniformity of treatment during this period, suggesting that significant differentiation had occurred prior to weaning. The large variance between animals could be explained by assuming that the genetic role in consumption of alcohol by C57BL mice is permissive--a relative insensitivity to the aversive orosensory and pharmacological effects of 10% alcohol--rather than a specific drug-seeking predisposition.

Alcohol Drinking↗
PubMed1988

Manipulation of alcohol preference in C57BL/6J mice by episodes of food poisoning.

Individual differences in the amount of alcohol consumed in a choice situation are found in highly inbred C57BL/6J mice. The extent to which environmental stress can modify alcohol preference was studied by coupling acute episodes of poisoning with restricted fluid availability, and recovery with free choice of drinking fluids. Addition of actinomycin D, a mycotoxin, to ordinary chow during 2-day periods produced acute episodes of nonlethal food poisoning from which the mice recovered rapidly. Consumption of a 10% alcohol solution and of water was recorded for several weeks before poisoning and for several weeks after the last episode. By varying drinking fluids available to the mice during the episodes of poisoning, long-lasting changes in alcohol preference were produced. When 10% alcohol was the sole drinking fluid available during poisoning, preference for the alcohol solution was abolished. When water was the sole fluid during poisoning, alcohol preference was increased above the already high levels established in the baseline and above a control group that was restricted to water during the treatment periods but was not poisoned. This increased alcohol preference was due to a nearly complete suppression of water intake in the posttreatment period; there was no significant increase in amount of alcohol consumed. The greatest individual differences in subsequent alcohol preference were found in the group of mice which continued to have free choice of alcohol and water during episodes of poisoning. The variety of responses to the same treatment show how environmental influences outside the experimenter's control may account for the variability found in voluntary alcohol consumption among genetically homogeneous mice.

Alcohol Drinking↗