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Biomedical subjects

D Knight

Publications and source records attributed to D Knight.

At least 73 records · Page 4Linked to original sources
PubMed1990

Chemical synthesis of dual-radiolabelled cyclandelate and its metabolism in rat hepatocytes and mouse J774 cells.

1. The chemical synthesis of 3,3,5-trimethyl[1-3H]cyclohexanol, 3,3,5-trimethyl[2,3-3H]cyclohexanol and 3,3,5-trimethyl[2,3-3H]cyclohexanyl[1-14C]mandelate (cyclandelate) are described. The ratio of 3H/14C radioactivity in the ester was 27:1. 2. Cultured rat hepatocytes accumulated trimethylcyclohexanol rapidly and excreted its glucuronide into the culture medium. Rat hepatocytes also accumulated cyclandelate rapidly, hydrolysing the ester and excreting trimethylcyclohexanol into the medium. This trimethylcyclohexanol then re-entered the cells and was converted to its glucuronide prior to excretion. 3. In contrast, no hydrolysis of cyclandelate was seen on incubation with J774 cells, a transformed mouse macrophage. 4. Similar differences in hydrolytic activity were seen with microsomal fractions prepared from rat liver and J774 cells. Hepatic microsomes caused a rapid hydrolysis of cyclandelate while no hydrolysis was detectable after incubations of over an hour with J774 microsomes. 5. This difference in hydrolytic activity may have important implications for the action of cyclandelate on cholesterol metabolism in extrahepatic tissues.

Animals↗
PubMed1990

Microcytosis, hypoferremia, hypoferritemia, and hypertransferrinemia in standardbred foals from birth to 4 months of age.

At birth, 24 Standardbred foals were assigned at random to 1 of 2 groups and were given a placebo supplement (group 1) or an iron supplement (248 mg of iron/treatment; group 2). Foals were given iron supplement or placebo 4 times during the second and third weeks after birth. Hematologic variables and general health were monitored until foals were 4 months old. Mean PCV in foals of both groups decreased during the first 2 weeks after birth, but values remained within adult horse reference ranges. During the first 6 weeks after birth, foal erythrocytes were smaller than adult horse erythrocytes, but foal erythrocyte glucose-6-phosphate dehydrogenase activity was greater than that in adult horses. At every measurement, indices of anisocytosis were lower in foals, compared with adult horse reference values, suggesting that foals have a homogeneous population of microcytic erythrocytes during early foalhood. In 2-week-old foals of both groups and in 4-week-old placebo-treated foals, mean serum iron concentration was lower than that in adult horses. In foals at birth and during the first 4 months, total iron-binding capacity values were above the adult reference range. In newborn foals, transferrin saturation percentage values decreased to below the reference range in foals from 2 weeks to 4 months after birth. When foals were born, serum ferritin concentration values were above the adult horse reference range, but decreased to within the reference range by the time foals were 1 day old. From 2 through 6 weeks after birth, foal ferritin concentration values were below the adult reference range.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1989

Colostral and serum IgG, IgA, and IgM concentrations in Standardbred mares and their foals at parturition.

Immunoglobulin G, IgM, and IgA concentrations were measured in serum collected from 36 Standardbred mares within 12 hours of foaling, in colostrum collected within 6 hours of foaling, and in serum collected from foals 24 to 48 hours after birth. In serum collected from mares after parturition, mean concentrations of IgG, IgM, and IgA were 2,463.9 +/- 1,337.3 mg/dl, 136.4 +/- 218 mg/dl, and 305.2 +/- 237.5 mg/dl, respectively. In serum from foals, mean concentrations of IgG, IgM, and IgA were 1,953.3 +/- 1,635 mg/dl, 33.8 +/- 30.4 mg/dl, and 58.4 +/- 42.2 mg/dl, respectively. In colostrum, mean concentrations of IgG, IgM, and IgA were 8,911.9 +/- 6,282.2 mg/dl, 957 +/- 1088.1 mg/dl, and 122.9 +/- 77.3 mg/dl, respectively. The IgG concentrations in foal serum were poorly correlated with IgG concentrations in colostrum (r = 0.462, P less than 0.01). Correlations of IgM or IgA concentrations in serum from foals with IgM or IgA concentrations in colostrum and correlations of IgG concentrations in serum from mares with those in colostrum were not significant (P less than 0.01). Of 36 foals, 1 (2.8%) had a serum IgG concentration less than 400 mg/dl. Of 36 foals monitored for 4 months, 6 developed infectious respiratory tract disease requiring antimicrobial therapy at ages varying from 55 to 113 days; these infections were probably not related to failure or partial failure of passive transfer of antibody.

Animals↗
PubMed1989

Characterization of a Pseudomonas sp. Capable of Aniline Degradation in the Presence of Secondary Carbon Sources.

Pseudomonas strain K1 is a gram-negative rod which grows aerobically on minimal media containing aniline with a doubling time of 2 h at 30 degrees C. The half-saturation parameter for aniline metabolism by aniline-grown cells was 3.8 mumol . liter. Concentrations of aniline as low as 50 nM were metabolized. Neither substituted anilines nor other aromatic compounds (other than aromatic amino acids) supported growth. Cells grew as fast on aniline as on nonaromatic substrates such as lactate. The aromatic ring was cleaved via the meta pathway. Catechol 2,3-oxygenase activity was induced by aniline, even in cultures containing alternative carbon sources such as lactate. Cultures grown on a mixture of aniline and lactate mineralized aniline in the presence of the second substrate. Lactate-grown cultures lacked catechol oxygenase activity, and resting cells from these cultures did not respire aniline. Resting cells from aniline-grown cultures exhibited high respiratory activity upon the addition of aniline or catechol, some activity with toluidine, and no activity after addition of a wide variety of other aromatic compounds, including dihydroxybenzylamine, chloroanilines, ethylanilines, aminophenols, aminobenzoates, and dihydroxybenzoates. Although substituted anilines were not metabolized, 3-or 4-chloroaniline did induce the enzymes for aniline oxidation.

Journal Article↗
PubMed1988

Imaging for infection: caution required with the Charcot joint.

Scintigraphic techniques for detecting bone infection can be misleading in neuroarthropathy (Charcot joint). Three patients showed strongly positive three phase bone and 67Ga imaging despite absence of osteitis. Indium labelled white cell imaging provided the correct information on each patient. The findings have important implications for the investigation of diabetic patients with suspected bone infection.

Adult↗
PubMed1988

The effect of firing temperature on the lung retention and translocation of Pu following the inhalation of 238PuO2 and 239PuO2 by CBA/H mice.

Mice were exposed by inhalation to sized aerosols of 238PuO2 and 239PuO2 which had been fired at temperatures from 550-1250 degrees C and groups killed at times between 1 d and 2 y after exposure. Measurements were made of 238Pu and 239Pu in the lungs, lung-associated lymph nodes, liver and skeleton. With 239Pu, lung retention and translocation were independent of firing temperature. With 238Pu on the other hand, the retention in lung was greater initially than for 239Pu but, with the low-fired oxide, eventually fell below that of 239Pu. With high-fired oxides, the lung retention of 238Pu still exceeded that of 239Pu after 2 y. Translocation to liver and bone was invariably greater for 238Pu than for 239Pu and was also dependent on firing temperature. The practical implications of these findings are discussed.

Administration, Inhalation↗
PubMed1988

Validation of the Children's Depression Scale and the Children's Depression Inventory in a prepubertal sample.

The validity of the Children's Depression Scale (CDS), the Children's Depression Inventory (CDI) and their respective parent report versions was assessed in a sample of outpatient and normal control prepubertal children. Scores from the child and parent versions of both scales significantly discriminated between children independently diagnosed as depressed and those with nondepressive disorders. Both measures also distinguished depressed and dysphoric children. Contrary to the findings of earlier studies, a significant rate of agreement was found between the reports provided by the children and their parents. The results suggest that the influence of the child's age and clinical status on reporter correspondence patterns should be considered more exhaustively in future research.

Child↗
PubMed1988

Laboratory evaluation of the Du Pont "Dimension Clinical Chemistry System".

We evaluated the analytical performance of the Du Pont Dimension Clinical Chemistry System to assess its suitability as a replacement for the Du Pont aca III, currently routinely used for analysis of pediatric, high-risk, and emergency specimens. Twenty-six analyses were studied. These generally fulfilled pre-set analytical goals for precision based on biological variation or "state of the art." Significant economies were achieved and we found the Dimension to be reliable, easy to operate, and simple to maintain. It also fulfilled safety requirements for analysis of specimens of high risk to laboratory staff.

Autoanalysis↗
PubMed1987

Complete interruption of the aortic arch in a dog.

Complete interruption of the aortic arch was diagnosed by angiocardiography in a dog with exercise intolerance, a cardiac murmur, polycythemia, and cardiomegaly. The defect was accompanied by a patent ductus arteriosus, ventricular septal defect, and subaortic stenosis. The dog was euthanatized, and the clinical diagnosis was documented by gross dissection of the heart. The site of aortic interruption was between the left carotid and left subclavian arteries, which is the most common location in human beings. The similarity with the pathologic findings of interrupted aortic arch in human beings suggests a similar mechanism responsible for the abnormal cardiac morphogenesis. The defect may be confused with other cardiac anomalies that can result in exercise intolerance, polycythemia, and cardiac murmur. This defect is amenable to surgical treatment, which emphasizes the importance of a correct anatomic diagnosis in clinical patients.

Animals↗
PubMed1986

Functional analysis and treatment of severe pica.

A two-phase functional analysis of a profoundly retarded 19-year-old male's pica facilitated the design of an effective intervention containing no aversive components. In the first analysis, frequent staff-client interaction resulted in 25% and 66% less pica than limited and no interaction, respectively. Paradoxical effects were obtained in the second analysis, where no protective helmet resulted in 38% and 26% less pica than the helmet with face shield and helmet without face shield, respectively. On the basis of these analyses, limited interaction and no helmet conditions were combined in an effective, staff-implemented treatment at a medium-sized institution.

Adult↗
PubMed1981

Enzyme immunoassay of phenobarbital, phenytoin, primidone, carbamazepine and theophylline with the Abbott VP Bichromatic Analyzer.

The enzyme multiplied immunoassay technique (EMIT) for the assay of phenobarbital, phenytoin, primidone, carbamazepine and theophylline was adapted to the Abbott VP Bichromatic Analyzer. Reagent consumption is reduced by the use of a stable working dilution of EMIT reagent B in EMIT buffer. Correlation with the standard EMIT method is excellent. This procedure greatly increases the maximum number of tests per kit. The method is an accurate and economical alternative to the standard EMIT method.

Carbamazepine↗