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Biomedical subjects

C M Thompson

Publications and source records attributed to C M Thompson.

At least 19 recordsLinked to original sources
PubMed1991

The effect of carbohydrates in milk on the absorption of calcium by postmenopausal women.

The purpose of this investigation was to determine if the presence of carbohydrate in milk, either lactose or its hydrolysis products, enhance the bioavailability of calcium (Ca) in milk. Two studies were performed. In study A, fractional Ca absorption was measured in 11 lactose-tolerant postmenopausal women after an oral dose of 47Ca-equilibrated milk formula containing no carbohydrate (NOCHO), lactose (LACTOSE), or an equivalent amount of glucose plus galactose (SUGAR); all participated in three absorption studies in random order. The NOCHO formula contained 10.0 g protein and 217 mg Ca from a combination of milk mineral and protein isolates; the LACTOSE and SUGAR formulae contained in addition 12 g lactose or 6 g glucose plus 6 g galactose, respectively. In study B, fractional Ca absorption was measured in five postmenopausal women after an oral dose of 47Ca-equilibrated skim milk (217 mg Ca) and lactase-treated milk, each with sufficient carbohydrate added to equal 12 g. For both studies, the increase in forearm radioactivity 4 and 8 hours after oral 47Ca administration relative to the increase observed after IV administration was used to estimate fractional Ca absorption. The addition of lactose but not glucose plus galactose to the NOCHO formula enhanced Ca absorption (p less than 0.05). Fractional absorption at 4 hours was 0.386 from the LACTOSE formula compared with 0.310 for both the NOCHO and SUGAR formulae. Those individuals with the lowest absorption in the absence of carbohydrate had the greatest increase with lactose. In contrast, Ca absorption was the same from skim milk as from lactase-treated skim milk (study B).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Contractile activity increases plasma membrane glucose transporters in absence of insulin.

To study the interactions between insulin and contraction on the skeletal muscle glucose transport system, the hindquarters of male rats were perfused in the absence of insulin, in the presence of insulin (30 mU/ml), during contractions induced by sciatic nerve stimulation, or during contractions plus insulin. Compared with control preparations, rates of glucose uptake in the perfused hindquarter were increased by 2.5- and 2.6-fold in the insulin and insulin plus contraction groups, respectively, but not significantly increased in the contraction only preparations. After perfusion, soleus and red and white gastrocnemius muscles from the hindquarter were pooled and used for the preparation of plasma membranes. Skeletal muscle plasma membrane vesicle glucose transport rates were 2.2 +/- 0.5, 7.9 +/- 1.7, 9.0 +/- 2.2, and 10.8 +/- 2.0 nmol.mg protein-1.s-1 (40 mM glucose), and plasma membrane glucose transporter numbers were 4.7 +/- 0.5, 8.1 +/- 0.9, 9.1 +/- 1.0, and 8.6 +/- 0.6 pmol/mg protein in the control, contraction, insulin, and insulin plus contraction groups, respectively. The transport-transporter ratio, an indication of plasma membrane glucose transporter intrinsic activity, was increased by contraction, insulin, and insulin plus contraction. These results demonstrate that contractile activity in the absence of insulin increases muscle plasma membrane glucose transport by increasing transporter number and intrinsic activity. In addition, under these experimental conditions, the effects of insulin and contraction to increase muscle glucose transport are not additive.

4-Nitrophenylphosphatase↗
PubMed1990

Skeletal muscle plasma membrane glucose transport and glucose transporters after exercise.

Recent reports have shown that immediately after an acute bout of exercise the glucose transport system of rat skeletal muscle plasma membranes is characterized by an increase in both glucose transporter number and intrinsic activity. To determine the duration of the exercise response we examined the time course of these changes after completion of a single bout of exercise. Male rats were exercised on a treadmill for 1 h (20 m/min, 10% grade) or allowed to remain sedentary. Rats were killed either immediately or 0.5 or 2 h after exercise, and red gastrocnemius muscle was used for the preparation of plasma membranes. Plasma membrane glucose transporter number was elevated 1.8- and 1.6-fold immediately and 30 min after exercise, although facilitated D-glucose transport in plasma membrane vesicles was elevated 4- and 1.8-fold immediately and 30 min after exercise, respectively. By 2 h after exercise both glucose transporter number and transport activity had returned to nonexercised control values. Additional experiments measuring glucose uptake in perfused hindquarter muscle produced similar results. We conclude that the reversal of the increase in glucose uptake by hindquarter skeletal muscle after exercise is correlated with a reversal of the increase in the glucose transporter number and activity in the plasma membrane. The time course of the transport-to-transporter ratio suggests that the intrinsic activity response reverses more rapidly than that involving transporter number.

Animals↗
PubMed1989

Cytotoxicity of Mycoplasma mycoides subspecies mycoides for cultured endothelial cells.

Toxic effect of 5 SC- and 4 LC-type strains of Mycoplasma mycoides subspecies mycoides has been demonstrated in cultured endothelial cells. The SC strains are agents of contagious bovine pleuropneumonia and presumably specific for cattle although occasionally isolated from goats. The LC strains produce an acute septicemic disease in goats and a few strains have been reported in cattle. The tissue culture cytotoxic dose causing 75% cell death (TCCD75) was calculated for each strain. Cytotoxicity ranged from 0.9 X 10(9) to 12.0 X 10(9) when strains were tested in bovine endothelial cells with the SC strains being twice as cytotoxic as the LC strains on average. Strains G175/78 and D44 representing the most cytotoxic SC and LC strains respectively, were selected for comparative experiments using bovine, caprine and porcine endothelial cells, bovine embryonic lung fibroblast cells (BELF) and the bovine cell line Madin-Darby kidney cells (MDBK). Strain G175/78 was significantly more cytotoxic for bovine endothelial cells than caprine and porcine, suggesting that the cytotoxicity reflects specificity for the bovine species. This strain was also cytotoxic for BELF but not for MDBK cells indicating that not all bovine cells are susceptible. Conversely, cytotoxicity of strain D44 was not significantly different in any of the endothelial cells tested, although cytotoxicity for BELF was significantly different, the cytotoxicity of the LC strains seems to be of less specificity.

Animals↗
PubMed1989

Do visibility and colour recognition isopters relate to the distribution of P alpha and P beta ganglion cells of the human retina?

Early perimetrists recognized that the threshold stimulus diameters for visibility and colour recognition differ markedly in peripheral vision. However, we observed that these diameters are identical at the fixation point. This means that these threshold diameters, when plotted against eccentric visual angle, have unequal slopes, perhaps related to recently reported data on estimated magnocellular and parvocellular neural sampling intervals. We therefore collected perimetric data on eleven normal observers, using red stimuli on the Zeiss Jena Type 1 Bowl Perimeter. It was found that the slopes were steeper than those for supposedly corresponding neural data. This could be explained by taking into consideration that (a) the slow rate of stimulus movement allowed parvocellular contribution to visibility; and (b) the possibility of an enhanced foveal representation in the cortical colour processing areas. The clinical significance of these findings is briefly discussed.

Adult↗
PubMed1989

Using evaluation strategies within a hospital-based dietetic education program: a case study.

A case study is presented to describe evaluation strategies used to document educational outcome resulting from a consortium-based hospital dietetic education program. Six supporting hospital facilities and 56 graduates were surveyed by questionnaire in June 1985. Within hospitals, results showed dietetic student time was defined as service-based for 46% of reported hours in foodservice experiences and for 54% in clinical experiences. A 71% graduate survey return revealed that 95% of the graduates sought and obtained employment after training, and 93% were employed in 1985 (classes 1974 to 1984).

Dietetics↗
PubMed1988

Regional brain trace-element studies in Alzheimer's disease.

Alzheimer's disease (AD) brain trace-element imbalances in the amygdala, hippocampus and nucleus basalis of Meynert (nbM) are found in most cases to be consistent with those previously reported in samples derived principally from AD cerebral cortex (Ehmann et al., 1986). The elevation of mercury in AD nbM, as compared to age-matched controls, is the largest trace-element imbalance observed to date in AD brain. In addition to the general confirmation of imbalances for Cs, Hg, N, Na, P, and Rb noted previously in cerebral cortex samples, imbalances for Fe, K, Sc, and Zn were observed in two regions and one region also exhibited imbalances for both Co and Se. Persistent imbalances for the univalent cations Na, K, Rb and Cs support arguments for a membrane abnormality in AD. The data presented here also provide the first comprehensive simultaneous multi-element determinations in both control and AD nbM.

Alzheimer Disease↗
PubMed1988

Rapid, inexpensive quality control of fluorine-18 2-deoxy-2-fluoro-D-glucose preparations using the hexokinase reaction in vitro.

A rapid enzymatic method for determining the purity of 2FDG preparations has been devised. A small aliquot of the preparation is incubated with a hexokinase/adenosine triphosphate/Mg+2 mixture and passed through a Dowex 1 ion-exchange column, which retains the 2FDG-6-phosphate. Another aliquot, without prior incubation, is passed through an identical column and the 2FDG radioactivity is found in the eluant. The criteria for purity are quantitative retention of the 2FDG-6-phosphate on the column and no retention of 2FDG. Comparison of the HK method with thin layer and high performance liquid chromatography assays indicate that the HK method can serve as a rapid, simple and inexpensive alternative to these other methods. It can be used in a routine quality control program and may be easily adaptable to automated 2FDG synthetic methods.

Chromatography, High Pressure Liquid↗
PubMed1987

Complementary components and local variations of the pattern electroretinogram.

Pattern electroretinograms have been presumed to arise from a combination of luminance and pattern detection activities. Since the responses at low spatial frequencies are linearly related to contrast and contain negligible pattern specific components, it is proposed that a retinal illuminance response for higher spatial frequencies can be computed from the optical transfer function of the eye. These computed responses are subtracted from pattern electroretinograms to reveal a pattern-specific response with a marked bandpass characteristic. The peak spatial frequency of the bandpass curve declines with increasing peripheral angle. For central vision, the peak amplitude of the pattern-specific response is larger than the retinal illuminance response, but, in the peripheral retina, the two responses are found to be almost equal. The possible origins of these signals are discussed, and it is concluded that the technique provides a method of obtaining separated illuminance and pattern responses from retinal regions having different properties of spatial selectivity.

Electroretinography↗
PubMed1986

Synthesis and radiolabeling of heterocyclic food mutagens.

The imidazoquinoline and imidazoquinoxaline food mutagens found in cooked meat are being synthesized by unambiguous methods that allow for the preparation of sufficient quantities of material for biological studies. These methods avoid difficult separations of regioisomeric mixtures of products and are designed to allow incorporation of specific high level tritium labeling.

Animals↗
PubMed1985

Clostridium difficile in patients with cystic fibrosis.

One hundred seven patients with cystic fibrosis (CF) and 54 other patients with risk factors for Clostridium difficile-associated disease were entered into a bacteriologic study to compare the rate of recovery of C difficile and cytotoxin in feces with occurrence of diarrhea and to investigate potentially protective or permissive relationships of fecal flora. Toxigenic C difficile was recovered from 22% of CF patients and 11% of patients with other diagnoses. Unlike the latter group, the majority (12/15) of CF patients who had cytotoxin recovered had formed stools and no history of diarrhea. Explanations for the lack of symptoms are speculative. Stool flora of CF patients was significantly more likely to include several bacteria with known inhibitory effects on C difficile. Recovery of C difficile and cytotoxin, however, was not associated with the decrease in rate of recovery or the mean bacterial count of any bacterium of fecal flora.

Adolescent↗
PubMed1985

Characteristics associated with outcome in a community mental health partial hospitalization program.

This study examined 17 characteristics of 519 clients in a large Midwestern partial hospitalization program which were thought to predict differential suitability for treatment. The Goal Attainment Scale, the Kincannon/Mini-Mult, and state hospital recidivism were used to establish outcome groups. Twelve of 17 characteristics were singularly associated with treatment outcome. Strongest associations occurred with the variables previous state hospitalizations, age at admission, age at onset, intelligence, and a parental incidence of mental illness. Models for predicting success were developed for discriminating successful from less successful clients.

Adolescent↗
PubMed1976

Comparison of methods for detection of particulate matter in large-volume perenterals.

The particulate matter content of six commonly used types of large-volume parenteral solutions was evaluated using five methods. The five methods were: (1) visual examination with the naked eye under diffuse light, (2) visual examination with a 2.5 diopter lens under diffuse light, (3) examination with a light scattering apparatus, (4) instrumental examination using the Prototron particle counter, and (5) a membrane filtration and microscopic examination technique. The visual methods (1) and (2) proved to be inadequate because of the insensitivity and high degree of subjectivity. The light-scattering apparatus was reasonably accurate and a considerable improvement over the first two techniques. The Prototron instrument was shown to be capable of predicting whether a solution would pass or fail the recently adopted USP-NF standards for particulate matter content, when compared with the membrane filtration and microscopic examination technique. All of the solutions tested were found to contain very low levels of particulate matter in relation to the USP-NF standard. It is recommended that this recently adopted standard be reevaluated with a view toward increased stringency.

Drug Contamination↗