Biomedical subjects

C H Clark

Publications and source records attributed to C H Clark.

At least 37 records · Page 2Linked to original sources

PubMed1989

Sonography in acute appendicitis.

In two patients with an equivocal clinical diagnosis of acute appendicitis, high-resolution sonography demonstrated an inflamed appendix. The appendix of each appeared grossly abnormal and was removed at laparotomy. Pathologic examination confirmed the diagnosis of acute appendicitis. Coupled with a review of the literature, the authors suggest high-resolution sonography as the examination of choice in patients with equivocal clinical findings of acute appendicitis.

Acute Disease↗

PubMed1987

Pharmacokinetics of oxytetracycline hydrochloride in rabbits.

Pharmacokinetics of oxytetracycline HCl (OTC) was studied in rabbits. After 10 mg of OTC/kg of body weight was administered IV, the distribution half-life was 0.06 hour, terminal half-life was 1.32 hours, volume of distribution area was 0.861 L/kg, and total body clearance was 0.434 L/kg/h. After 10 mg of OTC/kg was given IM, the absorption half-life was 2.09 hours, extent of absorption was 71.4%, and total body clearance of the absorbed fraction was 0.576 L/kg/h. Based on these kinetic data, a dosage of 15 mg of OTC/kg, every 8 hours was developed. This dose given IM for 7 consecutive days resulted in observed steady-state maximum and minimum concentrations (mean +/- SD) of 4.7 +/- 0.3 micrograms/ml and 3.2 +/- 0.6 micrograms/ml, respectively. Twice this dose (30 mg of OTC/kg, every 8 hours) given IM caused anorexia and diarrhea.

Animals↗

PubMed1986

Pharmacokinetics of cefotaxime in the domestic cat.

Cefotaxime was administered as single IV or IM dose for the purpose of examining its pharmacokinetics in healthy cats. The mean predicted plasma concentration of cefotaxime in 6 cats at 0 time after a single IV dosage of 10 mg/kg of body weight was 88.9 micrograms/ml. The mean plasma concentrations decreased to 10.8 micrograms/ml at 2 hours, 3.7 micrograms/ml at 3 hours, and 0.5 microgram/ml at 6 hours. The half-life was 0.98 +/- 0.25 hour (mean +/- SD), and the total body clearance was determined to be 2.76 +/- 1.25 ml/min/kg. After a single IM injection of 10 mg/kg of body weight, the mean maximum observed plasma concentration was 36.2 micrograms/ml at 0.75 hour. The mean absorption half-life was 0.24 hour. In 2 animals, the bioavailability of an IM injection was 98.2% and 93.0%.

Animals↗

PubMed1985

Plasma concentrations of chloramphenicol in snakes.

Plasma chloramphenicol concentrations after a subcutaneous injection were studied in 87 snakes of 16 different species. The biological half-life of chloramphenicol varied from 3.3 hours in the indigo snake (Drymarchon corais couperi) to 22.1 hours in the midland water snake (Nerodia sipedon). A single dosage of 50 mg of chloramphenicol/kg of body weight produced plasma concentrations greater than 5 micrograms/ml for nearly 72 hours in 2 species of water snakes (Nerodia erythrogaster, Nerodia sipedon), for 24 hours in the Burmese python (Python molurus bivittatus), and for less than 12 hours in the gray rat snake, Indigo snake, and eastern king snake (Elaphe obsoleta spiloides, Drymarchon coraise couperi, and Lampropeltis getulus getulus). A dosage of 50 mg/kg administered to water snakes every 72 hours for 18 days maintained a minimum plasma concentration of chloramphenicol between 2 and 5 micrograms/ml.

Animals↗

PubMed1983

Patients' perspectives of behavioral science care by family practice physicians.

Patients' concerns have too infrequently been considered by curriculum developers in the design of the behavioral science curriculum for family practice physicians. With these concerns in mind, the authors in this study examined by questionnaires patient attitudes regarding the level of involvement desired of family physicians for each of 45 psychosocial problems. The choices of responses offered were: Level 1, no help; Level 2, referral; Level 3, compassion, concern, and minor advice; and Level 4, expert, therapeutic help. The results demonstrated that for a majority of the problems, the patients expected their family physician to be caring and to show concern but not to be an expert (Level 3). Certain problems appeared in predictable categories, such as religion/church concerns in Level 1 and pregnancy, where expert advice was desired, in Level 4; pediatric problems dominated Level 2. Discrepancies between patient expectations and current curricular emphases were noted (for example, in counseling). Statistically significant differences were found between rural and urban populations as well as across low, middle, and upper socioeconomic classes. Educational implications derived from the data are discussed.

Adolescent↗

PubMed1982

Spontaneous neonatal gastric perforation.

Sixteen cases of spontaneous neonatal gastric perforation seen between January 1969 and March 1979 are reported. There were 13 surgically treated patients and three autopsy cases. This study provides information relative to the incidence among black populations, an incidence 1 per 2,900 live births. The entity is at least four times more common in males than females. All perforations occurred within the first week of life (average 72 hr). All perforations were on the greater curvature of the fundus. The operative mortality of this series is 7.5% (1 of 13) with an overall mortality of 25% (4 of 16). A gastrostomy was routinely done. No peritoneal cavity drainage or segmental gastric resection was necessary.

Diagnosis, Differential↗

PubMed1982

Defining a behavioral science curriculum for family physicians: What do patients think?

Patients have infrequently been assessed about their desire for their family physician to possess a certain level of expertise in managing a wide range of behavioral science problems. This has led to inconsistencies in the type of behavioral science training offered to family physicians and thence to a marked discrepancy between the amount of training offered (relatively large) and the amount of mental health care provided (relatively small). This study reports the result of a study of patient attitudes concerning the level of involvement by their family physician for each of 45 psychosocial problems. The levels offered were (1) no help, (2) referral, (3) compassion, concern, and minor advice, and (4) expert therapeutic help. The mean responses place a majority (25 of the 45) of the problems in level 3. Certain obvious problems appeared in level 1 (religious/church problems) and level 4 (pregnancy). Child behavioral problems dominated in level 2. Certain surprises were also found, such as the presence of problems of marital discord in level 1, and the problem of long-term pain in level 4.

Adolescent↗

PubMed1982

Plasma concentrations of chloramphenicol in birds.

The plasma concentrations of chloramphenicol after oral, IM, and IV administrations were studied in 15 species of birds. The biological half-lives of chloramphenicol ranged from 26 minutes in the pigeon, Columbia livia, to 288.3 minutes in the bald eagle, Haliaeetus leucocephalus. In those birds studied, the oral route gave low and inconsistent plasma chloramphenicol concentrations. The IM route was the most satisfactory. Based on the data presented, an IM dose of 50 mg/kg would produce plasma concentrations above 1 micrograms/ml for 8 to 12 hours, except in the pigeon, macaw, conure.

Animals↗

PubMed1981

Serum chloramphenicol concentrations in preruminant calves: a comparison of two formulations dosed orally.

Serum concentrations of chloramphenicol were determined after oral doses (55 mg/kg body weight) were administered to 7-9 day old Holstein-Friesian calves. Chloramphenicol in an oral solution produced greater serum concentrations than did an equivalent dose of chloramphenicol in capsules (P less than 0.005). A second dose of each formulation administered 12 h after the first dose elevated serum chloramphenicol concentrations significantly (P less than 0.001). The average serum chloramphenicol concentration exceeded 5 micrograms/ml of serum 1 h after administration of the solution compared with 4 h for the capsules. Average serum chloramphenicol concentration was greater than 5 micrograms/ml for at least 12 h after the dose was administered for both formulations. Of the eight calves receiving repeat doses of chloramphenicol, seven (87.5%) developed diarrhea in 76 +/- 8.6 h. Six of the eight calves (75%) died during or shortly after the period of chloramphenicol administration.

Administration, Oral↗

PubMed1981

Representative oxygen dissociation curve and equation for the chicken.

Because of the considerable variability in the oxygen dissociation curves for chickens reported in the literature, the respiratory physiologist studying avian gas exchange is faced with the dilemma of which curve is representative for the chicken. In order to arrive at a representative curve, data from eight reported curves were compiled and adjusted to the same set of standard conditions of temperature (T), pH, and partial pressure of carbon dioxide (PCO2): T = 42 C, pH = 7.5 PCO2 = 40 torr. The mean PO2 STD (mean +/- SD) versus percent saturation of hemoglobin curve was then determined. The mean data were fitted to an equation representing the oxygen dissociation curve so that for any selected partial pressure of oxygen (PO2) the percent saturation (%SAT) of oxyhemoglobin may be computed. The P50 values for the mean literature and equation curves, respectively, were 47.4 +/- 9.8 and 45.3 Torr. The mean curve with its standard deviations provides a chicken oxygen dissociation curve representative of the literature data to which experimental data may be compared. The equation for the curve enables rapid referral to the representative curve to compute the %SAT, given the PO2 adjusted to the standard conditions.

Animals↗

PubMed1980

Chicken oxygen dissociation curve by dynamic tonometry.

Oxygen dissociation curves were determined for blood from mature (5 male, 5 female) Single Comb White Leghorn chickens. Blood was oxygenated by bubbling with humidified 95% O2, 5% CO2, 0% N2 at 100 ml/min for 30 min, then gradually deoxygenated with 0% O2, 5% CO2, 95% N2 at 4 ml/min. During deoxygenation .5 ml samples were drawn at 7 in intervals. The PO2, PCO2, and pH were measured polarographically and the content of O2 was measured by gas chromatography. The PO2 was corrected to T = 42 C, pH = 7.5, and PCO2 = 40 Torr. The curves were determined by plotting: 1) PO2 vs. % Saicont based on O2 content of each serial sample as compared to the fully oxygenated blood O2 content, and 2) PO2 vs. duration of dynamic tonometry plots. The curves determined by the two methods of data analysis corresponded closely, the P50 values (x +/- SD) being 36.2 +/- 2.5, 34.3 +/- 3.1 Torr, respectively.

Animals↗

PubMed1980