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Biomedical subjects

C M Thompson

Publications and source records attributed to C M Thompson.

At least 73 records · Page 4Linked to original sources
PubMed1993

Can bio-electrical impedance be used to measure total body water in dialysis patients?

The measurement of total body water (TBW) by bio-electrical impedance (BEI) in a group of renal patients was evaluated against the tritium dilution method. The effect of haemodialysis and the presence of peritoneal dialysate on the impedance were also investigated. The correlation between the two methods was r = 0.9, with the standard deviation of the differences being 3.66 l (TBW typically 40 l). The BEI method overestimated the actual weight loss after haemodialysis, but underestimated the volume of peritoneal dialysate in situ. The BEI method would not be appropriate for use in assessing total body water and monitoring acute volume changes in patients with renal failure who are on strict fluid restriction.

Adult↗
PubMed1993

Determination of total body water in uraemic patients by bioelectrical impedance.

The measurement of total body water by bioelectrical impedance in a group of renal patients was evaluated against the tritium dilution method. The effect of haemodialysis and the presence of peritoneal dialysate on the impedance were also investigated. The correlation between the two methods is r = 0.90 with a residual standard deviation of 3.7. The standard deviation of the differences between the two methods against the means was 3.66 which means that total body water (TBW) estimated by the bioelectrical impedance (BEI) method may be 6.18 l (X +/- 2 SD) above or 8.38 l below the 3H2O method. The BEI method overestimated the actual weight loss after haemodialysis (3.87 +/- 1.7 l versus 2.43 +/- 1.8 l) but underestimated the volume of peritoneal dialysate in situ. The BEI method would not be appropriate for use in assessing total body water and monitoring acute volume changes in patients with renal failure who are on strict fluid restriction.

Adult↗
PubMed1993

Infants of less than 1250 grams birth weight at Groote Schuur Hospital: outcome at 1 and 2 years of age.

A prospective 2-year follow-up study of infants with birth weights of less than 1250 g was undertaken at Groote Schuur Hospital Neonatal Intensive Care Unit. For a 12-month period beginning July 1988, all live infants born at Groote Schuur Hospital or referred to the Neonatal Intensive Care Unit were included in the study cohort. The aim of the study was to document the morbidity, mortality, and neurodevelopmental outcome of these infants to 2 years of age. Of 235 liveborn infants, 143 (61%) survived to discharge. One hundred twenty-six infants were born weighing less than 1000 g; 42% survived to discharge. One hundred nine infants weighed 1000 g or more at birth, and 83% survived to discharge. Better survival was documented for infants whose mothers attended antenatal care, who weighed more than 900 g, and who were of greater than 30 weeks' gestation. Eleven infants died in the first 6 months after discharge. One hundred six infants (83% of survivors) underwent Griffiths developmental testing and clinical assessment at 1 year of age. Ninety-six (91%) of these survivors were seen and tested at 2 years of age. Of the 106 infants assessed at 1 year of age, 6 infants had cerebral palsy, 6 were globally developmentally delayed without signs of cerebral palsy, and 1 infant showed significant motor delay with a normal developmental quotient. At 2 years of age 1 additional infant had cerebral palsy and 9 more infants are likely to be mentally retarded. At 2 years of age the major handicap rate was, therefore, 22%. Sixty-nine percent of surviving infants, and all but 1 of the infants with cerebral palsy, were underweight for gestational age at birth. There was a tendency for these underweight-for-gestational-age infants to score less well at 2 years of age. Infants who received ventilation and infants with a birth weight of less than 1000 g were not found to score less well than other infants in the cohort.

Birth Weight↗
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

Teaching MEDLINE to non-urban end users.

The University of Oklahoma Health Sciences Center (OUHSC) Library conducted a two-year program, funded by the National Library of Medicine (NLM), to teach Oklahoma's nonurban health professionals to perform searches of NLM's MEDLINE files using microcomputers. The training program included lectures, online demonstrations, and hands-on practice time. The initial target audience of non-urban physicians was later broadended to include other health professionals. Data collected on the 334 seminar participants included professions and specialties, previous microcomputer usage, and the size of their hospitals. On-site evaluation indicated a high degree of satisfaction with the trainers' communication skills, preparation, information imparted, and the visual aids used. The results of a follow-up survey to determine how many trainees subsequently obtained NLM codes, the amount of searching done, and the problems experienced await analysis.

Academic Medical Centers↗
PubMed1989

Analysis of non-urban end users' MEDLINE training.

The University of Oklahoma Health Sciences Center (OUHSC) Library mailed a MEDLINE End User Practice Survey Form to 310 health professionals who had attended MEDLINE seminars supported by a two-year NLM grant. The survey sought to determine how many respondents had obtained NLM codes, reasons for not obtaining a code, searching time done since the seminar, differences in the use of information since taking the seminar, factors helpful in successful searching, and factors contributing to frustrations. The most prevalent reasons for not obtaining a code were lack of a microcomputer and modem, infrequent use of MEDLINE, cost, lack of time, complications, and ability to obtain free searches.

Computer User Training↗
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↗