Search PubMed⌕ Search

Biomedical subjects

J Fowler

Publications and source records attributed to J Fowler.

At least 145 records · Page 8Linked to original sources

Cytochrome P-450 localization in normal human adult and foetal liver by immunocytochemistry using a monoclonal antibody against human cytochrome P-450.

Immunocytochemical studies with a monoclonal antibody (MAb-HL3), which recognises a major isozyme of human hepatic cytochrome P-450, have demonstrated this cytochrome in both cryostat and formalin-fixed paraffin-embedded sections of normal human adult liver. Prior trypsin digestion of the formalin-fixed sections prevented staining. There was a zonal distribution of immunoreactive cytochrome P-450, with localization predominantly in the hepatocytes of zone 3 of the hepatic acinus (the centrilobular region). Cytochrome P-450 was also demonstrated in foetal liver, but all foetal hepatocytes contained immunoreactive cytochrome P-450 and there was no zonal distribution of the protein. The biliary epithelium of adult liver contained a small amount of immunoreactive cytochrome P-450 whereas there was no immunoreactivity in the epithelium of foetal bile ducts.

Adult↗

Pharmacokinetics of ketoprofen in rabbit after a single topical application.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used by topical application in management of joint pain and inflammation. Little is known, however, about their pharmacokinetics, especially in the synovial compartment versus the plasma compartment, following topical administration. Ketoprofen, a NSAID, was delivered by a single topical application (KETUM 2.5% gel) on the rabbit knee-joint region of one hind limb. Concentrations of ketoprofen were measured in plasma, synovial fluid, joint capsule and synovial fat tissue at 2, 4, 6 and 12 hours after application. Whatever the time period after application, ketoprofen concentrations in synovial fluid were much higher than in plasma. The time-course of the decrease in ketoprofen plasma concentrations was more rapid than that in synovial fluid. Similarly, concentrations in joint capsule were higher than those found in synovial fat tissue. Finally, while ketoprofen concentrations decreased rapidly in plasma and in synovial fat tissue, concentrations in joint capsule and particularly in synovial fluid were more sustained. The increase in residence time of ketoprofen in synovial fluid could be in favour of its efficiency in the management of joint pain and inflammation.

Administration, Topical↗

Positron emission tomography studies of normal aging: a replication of PET III and 18-FDG using PET VI and 11-CDG.

Using PET VI and 11-CDG we replicated our earlier PET III and 18-FDG normal aging findings. Examination of young and old normal volunteers revealed the absence of any absolute regional age-related changes in glucose utilization. For the combined sample (N = 81) we did find evidence to suggest a relative hypofrontal change with increasing age. A strong relationship between age and ventricular size (CT) was also found. These findings suggest the preserved glucose metabolism of the resting aging brain in the presence of structural atrophic changes.

Adult↗

Hippocampal formation glucose metabolism and volume losses in MCI and AD.

We used MRI volume sampling with coregistered and atrophy corrected FDG-PET scans to test three hypotheses: 1) hippocampal formation measures are superior to temporal neocortical measures in the discrimination of normal (NL) and mild cognitive impairment (MCI); 2) neocortical measures are most useful in the separation of Alzheimer disease (AD) from NL or MCI; 3) measures of PET glucose metabolism (MRglu) have greater diagnostic sensitivity than MRI volume. Three groups of age, education, and gender matched NL, MCI, and AD subjects were studied. The results supported the hypotheses: 1) entorhinal cortex MRglu and hippocampal volume were most accurate in classifying NL and MCI; 2) both imaging modalities identified the temporal neocortex as best separating MCI and AD, whereas widespread changes accurately classified NL and AD; 3) In most between group comparisons regional MRglu measures were diagnostically superior to volume measures. These cross-sectional data show that in MCI hippocampal formation changes exist without significant neocortical changes. Neocortical changes best characterize AD. In both MCI and AD, metabolism reductions exceed volume losses.

Aged↗

The effects of dietary fibre on upper and lower gastro-intestinal transit times and faecal bulking.

A total of 10 obese patients (body mass index greater than 25) undergoing treatment with a very low-calorie (330 kcal/day) liquid diet were treated without and with 10.5 or 21 g/day dietary fibre. Mean (+/- SE) faecal bulking increased significantly (P less than 0.001) in a dose-dependent manner from 314.8 +/- 54.4 g on a fibre-free diet to 517.2 +/- 45.4 g and 748.9 +/- 78.5 g, respectively, over 5 days on diets containing 10.5 and 21 g/day dietary fibre. Total mean colonic transit time decreased from 53.9 +/- 3.6 h on a fibre-free diet to 25.8 +/- 44 and 17.3 +/- 4.6 h, respectively, on diets including 10.5 and 21 g/day dietary fibre. Both right and left colonic transit times were similarly affected but no effect on orocaecal transit time was detected.

Body Mass Index↗

The preclinical assessment of the risk for QT interval prolongation.

Some drugs have been reported to induce severe ventricular arrhythmias, including torsades de pointes, and have been responsible in some cases for sudden death of patients. Although the mechanisms of these arrhythmias are not well understood, they are often, but not always, associated with QT interval prolongation. Regulatory authorities (CPMP in Europe) have recently pointed out the necessity to assess most carefully the potential, especially of non-cardiovascular drugs, for QT interval prolongation. Different methodological approaches are presented in this paper and experimental protocols are suggested; limitations and advantages of the presently available in vitro and in vivo models are discussed. It appears that both in vitro and in vivo approaches are complementary. In particular it is pointed out that only the in vitro models using isolated cardiac tissues (Purkinje fibres or papillary muscles) enable assessment of the drug properties under low cardiac rhythm conditions. This model allows us to mimic pathological situations of long QT interval (such as acquired or congenital long QT syndrome) in which most of the major clinical problems are encountered. Finally, a strategy for the preclinical assessment of the potential of a molecule for QT interval prolongation is presented.

Animals↗