Search PubMed⌕ Search

Biomedical subjects

B W Watson

Publications and source records attributed to B W Watson.

At least 19 recordsLinked to original sources
PubMed1998

Sensitive method for measuring tissue alpha-tocopherol and alpha-tocopheryloxybutyric acid by high-performance liquid chromatography with fluorometric detection.

The nonhydrolysable tocopherol ether analog, d-alpha-tocopheryloxybutyric acid (TSE), and its tocopherol ester counterpart, d-alpha-tocopheryl hemisuccinate (TS), have been shown to possess anti-tumor activity. In the present study, a sensitive high-performance liquid chromatography (HPLC) method using fluorometric detection is described for the simultaneous determination of TSE and alpha-T in biological specimens. Maximal sensitivity for the measurement of TSE and alpha-T was observed with the wavelengths, 210 nm excitation and 300 nm emission. Using an internal standard (I.S.) method, the amount of these tocopherol compounds was determined in standards, liver homogenates isolated from rats administered TSE-tris salt or vehicle (saline) and in HL-60 human leukaemia cells incubated with TSE-tris salt or saline. Treatment with TSE resulted in the significant accumulation of TSE, but not alpha-T, in the liver and HL-60 cells.

Animals↗
PubMed1990

Predictive value of oesophageal pH variables in children with gastro-oesophageal reflux.

Sixty three 24 hour oesophageal pH studies were performed in children with known or suspected gastro-oesophageal reflux and their progress was followed for at least a year. Forty two studies were of children who were well at follow up who were not receiving medical treatment for gastro-oesophageal reflux, and had not required antireflux surgery. Twenty one studies were from children who were still on treatment for gastro-oesophageal reflux or had undergone antireflux surgery. The results were analysed using non-parametric statistics to assess the value of pH recordings in predicting which children were likely to have continuing problems. Sleep reflux (minutes/hour) and acid clearing time were the most highly significant variables (p less than 0.0005 and p less than 0.0001 respectively). The results suggest that either sleep gastro-oesophageal reflux of more than 6.4 minutes/hour or an acid clearing time of seven minutes or more are good predictors of the clinical outcome (specificity 88.1%, sensitivity 81.0%). Three of the five children with false positive results were under 10 months of age. Positive results in this age group should therefore be interpreted with caution.

Adolescent↗
PubMed1988

Activity rhythms of hamsters in a single cage compared to a simulated burrow system.

A method for measuring activity of hamsters using a stabilimeter at a 1 second sampling rate with data computer recorded as 5 minutes integrated values was developed. In a single cage without a running wheel a consistent pattern for activity was observed, consisting of (a) low levels of daytime activity until one or two hours before lights off when activity increased significantly; and (b) a peak of nocturnal activity in the first hour of the dark cycle. The inclusion of a running wheel increased and altered significantly the pattern of nocturnal activity. In further experiments animals were housed in two linked cages, one acting as light-proof burrow and the other exposed to light. Measurements were recorded from each cage independently and from two position detectors in the interconnecting tunnel. The results showed: (a) total activity, i.e., the summation of activity in both cages, was not different from activity in a single cage system; (b) low daytime activity was composed of prolonged periods of rest in the burrow plus short periods of activity in the exposed cage; the increased activity one hour before lights off was localised to the light-proof burrow; and (c) after lights off, the animals began to spend increasing periods of time in the exposed cage reaching a maximum after one hour. Replacing artificial with natural light did not change the principal features of behaviour.

Animals↗
PubMed1987

The pattern of motor activity, light, and melatonin production in Syrian hamsters.

To investigate the motor rhythm of the Syrian hamster under natural photoperiod and to relate these findings to pineal rhythm, animals were left undisturbed in metabolic cages in which stabilimeter systems registered motor activity, photovoltaic cells registered light intensity, and in which urinary output was used for the assay of the major melatonin metabolite 6-sulphatoxymelatonin. The motor activity of two animals was monitored during 1 month and showed a striking similarity. Melatonin secretion was measured during 3 consecutive days and showed a night/day ratio in both animals that was relatively constant and that was coupled to the diurnal rhythm of the animals' activity.

Animals↗
PubMed1986

Effect of extremely-low-frequency pulsed magnetic fields on the mitogenic response of peripheral blood mononuclear cells.

The effect of extremely-low-frequency pulsed magnetic fields (PMF) on the response of human peripheral blood mononuclear cells to mitogenic stimulation is reported. We investigated 25 healthy control subjects. Mitogen-stimulated mononuclear cells were exposed to PMF for 72 h and an inhibition of 3H-thymidine uptake was observed in all but one subject. The degree of inhibition of 3H-thymidine uptake was as much as 60%. There was no significant difference between the blastogenic responses of mononuclear cells exposed to PMF for 12 h and control cultures. This study establishes an inhibitory effect of PMF on an in vitro measure of immune function.

Adult↗
PubMed1984

Determination of extracellular pH and tissue temperature in transplantable rat tumors by use of inductive loop telemetry.

Radiotelemetry was used to determine changes in extracellular pH and tissue temperature during tumor development in rats of an inbred WAB substrain. A progressive decrease in the pH of the tumor tissue compared with the pH level in control tissue was observed, so that by 4 days after tumor implantation the tumor tissue was about 0.4 pH units lower than control values. Thereafter, tumor pH rose progressively to reach a value comparable with control levels at 8 days, when the experiment was terminated. No significant difference was detected between the temperature in the tumor tissue and the temperature in the control tissue. Therefore, the observed changes in pH appeared to be independent of temperature. Studies on the rate of tumor cell proliferation during the experiments demonstrated a significant inverse relationship between tumor cell mitotic rate and pH, with the highest rates of cell proliferation occurring at the time of lowest pH values.

Animals↗
PubMed1981

An accurate, long-term, pH-sensitive radio pill for ingestion and implantation.

The design of a new radiotelemetry capsule (26 mm long X 7.6 mm diameter), with an in vivo life of 1 month is described in the context of previous work in this field. In vitro evaluation of the capsule indicates an accuracy and performance comparable with a conventional pH meter. Several clinical applications are described, including measurements of gastrointestinal pH in humans and the measurement of extracellular pH in laboratory animals.

Animals↗
PubMed1976

The effect of temperature on canine papillary muscle.

Measurements of the total duration, tA, of the action potential for canine papillary muscle in the temperature range 25-45 degrees C are shown to follow the law ta = tau exp (Q/kBT), with tau and the activation energy Q independent of temperature, T, and kB equal to Boltzmann's constant. The value obtained for Q = 0.65 +/- 0.10 eV. Results are also presented for the temperature dependence of points V(x) on the action potential curve, where x is the percentage of repolarisation within the range 30% less than x less than 100%.

Action Potentials↗
PubMed1976

The contingent negative variation and psychological findings in chronic hepatic encephalopathy.

Early diagnosis of chronic hepatic encephalopathy (CHE) in the latent stage before the appearance of clinical signs, should reduce both morbidity and mortality as deterioration is often preventable by treatment. Since existing diagnostic procedures are inadequate, we have investigated a test in which morphine is used as a provocative agent and any resulting change in cerebral function assessed by measurement of the CNV in conjuction with a psychological trail test. Twenty six patients were studied, 6 of whom had clinically overt CHE. A significant correlation (P less than 0.05) between the change in CNV amplitude with morphine and the initial CNV amplitude, consistent with the theoretical model of Tecce (1972), was found. However, the CNV and trail test results taken as a whole did not allow even those patients with overt CHE to be distinguished and we conclude that it is unlikely that differing degrees of latent CHE could be detected.

Chronic Disease↗
PubMed1976

Effect of long-term ionized air treatment on patients with bronchial asthma.

Seven patients with bronchial asthma requiring continuous medication were subjected to eight weeks of nocturnal exposure to negatively ionized air, and their progress was followed using objective tests of lung function and clinical assessment. During exposure, four patients showed significant increases in morning PEFR, which in two of these patients was not sustained when exposure ceased. In two patients the observed increase in PEFR was accompanied by subjective improvement. From the results of all our assessments we conclude that, although this treatment may lead to an improvement in some patients with asthma, further objective studies are required to determine the value of negatively ionized air in the routine management of asthma.

Adult↗
PubMed1975

Theory of hydrokinetic clearance of bacteria from the urinary bladder. I. Effect of variations in bacterial growth rate.

If the bladder is regularly emptied in appropriate circumstances the concentration of bacteria in successively voided samples progressively falls. By making a number of assumptions about conditions of bacterial growth in the bladder the way in which this washout of bacteria will occur can be predicted. Such predictions give a form of washout curve which differs significantly from that commonly encountered in patients. The shape of the predicted washout curve is affected by the form of the bacterial growth curve but this influence is not sufficient to account for the observed difference between patients and predictions.

Bacteriuria↗