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Biomedical subjects

M Caldwell

Publications and source records attributed to M Caldwell.

At least 37 records · Page 2Linked to original sources
PubMed1992

Self-reported and measured weights and heights of participants in community-based weight loss programs.

Self-reported weights and heights of 82 adults were compared with measured weights and heights 1 to 3 years after participation in community weight loss programs. The mean self-reported weight was 2.3 +/- 1.9 kg lower than measured weight (P < .05). Differences in underreporting were not significant for gender or age group. Heavier individuals misreported their weight to a greater extent (P < .05) than lighter persons, and individuals who had not recently weighed themselves underreported their weight to a greater extent than those who had weighed recently (P < .05). On the average, height was overreported by a mean of 1.8 +/- 2.7 cm. Overreporting increased with increasing height, and men overestimated their height to a greater extent than women (P < .05). Younger subjects reported their height more accurately than those older than 60 years. Results of our study are similar to those of previous investigations that examined self-reporting bias in subjects enrolled in weight loss programs. The mean discrepancy in body weight, however, was greater than that reported in samples drawn from the general population. Our findings indicate that self-reported weight and height values in overweight populations should be interpreted with caution.

Adult↗
PubMed1990

Vitamin A gastrointestinal absorption in persons with Down's syndrome.

The total daily vitamin A intake, physical signs associated with vitamin A deficiency, and the response to a vitamin A challenge were studied in 33 patients with Down's syndrome and in 14 intellectually normal persons (comparison group). The evaluation of detailed dietary histories revealed that the study subjects' mean daily vitamin A intake was similar to the recommended daily allowance for adults and that there was no significant difference of the mean daily vitamin A intake between study and comparison groups (5029 IU and 5706 IU, respectively). Subjects with Down's syndrome had more symptoms usually seen in patients with hypovitaminosis A than the persons in the comparison group. The baseline serum vitamin A levels in the Down's syndrome and comparison groups were within the normal range (106.0 micrograms/dl and 136.5 micrograms/dl, respectively). The vitamin A absorption curve of persons with Down's syndrome paralleled that of normal individuals and no significant difference of vitamin A levels between study and comparison groups was observed except for the 6-h values. Also, the absorption differential (delta = 3-h value + 6-h value/2-O-h value) did not show a significant difference between the two groups. Thus, these investigations do not support previous reports of significantly decreased vitamin A absorption in individuals with Down's syndrome.

Adolescent↗
PubMed1989

Malignant melanoma lately diagnosed.

To assess the clinical impression that patients in Dublin were presenting with late, deep, poor prognosis lesions, a 10 year retrospective review of patients with malignant melanoma was performed. The pathological data on 186 patients was examined and clinical follow-up obtained on 151 of these (80%). The mean period of follow-up was 35 months. Females predominated in a ratio of 3:1. Incidence figures for the two five year periods (1976-80) and (1981-85) indicated a rise in the latter period of over 100%. There was a marked delay in presentation after the onset of symptoms i.e. new pigmented lesions or changes in pre-existing lesions (mean = 21 months). Only 45% of lesions were less than 1.5mm in depth. Females presented with a higher percentage of good prognosis lesions reflected in a superior five year survival figure of 70% compared with 43% for males. The results of this study suggest an increase in incidence and mortality from malignant melanoma in this country. Patients appear to be unaware of the significance of pigmented lesions, presenting late with deep poor prognosis tumours.

Adolescent↗
PubMed1988

Preferential cytotoxicity on tumor cells by caffeic acid phenethyl ester isolated from propolis.

The honeybee hive product, propolis, is a folk medicine employed for treating various ailments. Many important pharmaceutical properties have been ascribed to propolis, including anti-inflammatory, antiviral, immunostimulatory and carcinostatic activities. Propolis extracts have provided an active component identified as caffeic acid phenethyl ester (CAPE), which was readily prepared in one step. Differential cytotoxicity has been observed in normal rat/human versus transformed rat/human melanoma and breast carcinoma cell lines in the presence of CAPE.

Animals↗
PubMed1988

Deep venous thrombosis, inflammatory bowel disease, and protein S deficiency.

The authors observed a patient with severe inflammatory bowel disease (IBD) complicated by ten episodes of deep venous thrombosis (DVT). Her unusual thrombotic tendency prompted further investigation for primary hypercoagulability. A nonfamilial deficiency of Protein S was documented suggesting the deficiency was acquired. This occurrence suggests that low Protein S levels should be considered as a potential etiologic factor in patients with IBD and recurrent DVT.

Adult↗
PubMed1987

Sequential studies of skin tumorigenesis in phosphoglycerate kinase mosaic mice: effect of resumption of promotion on regressed papillomas.

Most mouse skin papillomas induced by 7,12-dimethylbenz(a)-anthracene initiation followed by 12-O-tetradecanoylphorbol-13 acetate (TPA) promotion are benign promoter-dependent papillomas which regress after cessation of promotion, but some benign tumors (promoter-independent papillomas) do not regress, and a few carcinomas seem to develop from progressive growth of these tumors. We have tested whether a second course of TPA promotion induces regeneration in regressed promoter-dependent papillomas and advances them to malignancy. The regression and regeneration of these papillomas were determined by serial photographs, measurements of coordinates, histopathological evaluation, and X-chromosome-linked phosphoglycerate kinase enzyme cellular markers. Most of the regressed promoter-dependent papillomas did not regenerate. However, the second course of TPA promotion induced rapid development of many new papillomas, some of which advanced to promoter-independent papillomas and a carcinoma. This finding suggests that there are more abnormal cells in the initiated mouse skin than those detected with a single course of TPA promotion.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1987

Studies of skin tumorigenesis in PGK mosaic mice: many promoter-independent papillomas and carcinomas do not develop from pre-existing promoter-dependent papillomas.

The induction of mouse skin papillomas in two stages by initiation-promotion protocols has been studied extensively. On the basis of kinetics of induction and morphological observations of apparent progression to carcinomas, it has been argued that the papillomas sequentially advance to carcinomas through promoter-dependent and promoter-independent premalignant stages. Although this hypothesis has been widely accepted, the step-wise development of the same cell population from papilloma to carcinoma has not been established at the cellular level. We show here that some carcinomas which morphologically appear to result from progression of promoter-dependent papillomas do not develop from sequential progression of the same cell population as was found in the original papillomas. Other initiated cells also participate during the growth of these tumors and may replace the original papilloma cells. We also present evidence that some tumors develop directly as promoter-independent papillomas without going through an apparent promoter-dependent papilloma stage.

Animals↗
PubMed1987

The effect of the hypoferremic response on iron acquisition by and growth of murine lymphoma cells.

The hypoferremic response in C57 black mice during EL4 lymphoma cell growth was followed to determine if a lowered transferrin iron saturation inhibited iron acquisition and growth by these tumor cells. Although the lymphoma induced a strong hypoferremic response, it occurred late in the disease when the tumor burden was high and did not appear to effectively limit tumor cell growth, as all mice subsequently died. The induction of a hypoferremic response early in the disease with subcutaneous injections of turpentine also did not inhibit tumor cell growth. Parallel in vitro cell growth experiments revealed iron to be readily available to the lymphoma cells, regardless of whether the transferrin pool was 100, 50, or 10% saturated with iron. The dynamics of 59Fe uptake by the lymphoma cells from 50% saturated ferritransferrin were followed and saturation of iron uptake was found to occur at 150 nM iron and transferrin, far below physiological levels. Lowering transferrin saturation from 50 to 10% did not result in a proportional decrease in 59Fe uptake. Thus the ability of the EL4 tumor cells to obtain iron appeared to exceed the ability of a vigorous murine hypoferremic response to sequester it, suggesting that the hypoferremic response does not effectively limit EL4 ascites tumor cell growth.

Animals↗
PubMed1985

Macrophage interaction with skeletal muscle: a potential role of macrophages in determining the energy state of healing wounds.

A decrease in ATP and creatine phosphate (CP) is characteristic of local injury to skeletal muscle. Recent data have suggested adequate potential for high-energy phosphate production in the wounded tissue. Thus, an adequate explanation for the deficit in the high-energy tissue content in wounds was lacking. Since the wound has multiple components (muscle + cellular infiltrate), the tissue content represents the summation of these components. Therefore, a technique to separate these components was designed. Using a 0.5% solution of lambda-carrageenan as the wounding agent, the extensor digitorum longus muscles (EDL) of male Fisher rats were unilaterally wounded with intramuscular injections. Five days later, both wounded and contralateral nonwounded muscles were incubated in a standardized fashion. The groups of EDL were: wounded as described, contralateral nonwounded, or contralateral nonwounded with the addition to the incubate of 6 X 10(6)/ml lambda-carrageenan elicited peritoneal macrophages. Following incubation, the individual component parts of the system (muscle and macrophage) were rapidly frozen and assayed for high-energy phosphate and DNA content. Examination of the high-energy phosphate content of the separate components of a wound demonstrated that macrophages increased the ATP and CP content of normal skeletal muscle. Yet when total high-energy phosphate content was normalized for total DNA (muscle + macrophages) in the reconstituted system, the values approximated those of wounded muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1979

Assessment of maternal nutrition.

A booklet, "Assessment of Maternal Nutrition," has been published by the American College of Obstetricians and Gynecologists in cooperation with The American Dietetic Association as a useful guide for physicians, nurses, dietitians, and nutritionists. Nutritional risks during pregnancy are clearly outlined. Clinical, dietary, and biochemical factors, as well as medical, obstetric, and social factors, are delineated as components of nutritional assessment. An A.D.A. Liaison Committee had major responsibility for the development of the "Eating Habits Questionnaire," a tool to screen dietary intake for major deficits and excesses, which is included in the booklet. It should be useful also as a starting point for nutrition education. Additional evaluation of the use and reliability of the screening tool is recommended.

Adolescent↗
PubMed1978

Cytochemical localization of adenylate cyclase in broken cell preparations of the cerebral cortex.

Broken cell preparations derived from rat cerebral cortical grey matter were studied cytochemically to localize adenylate cyclase (AC) activity in subcellular organelle membranes. AC activity was localized by visualizing reaction product in brain particulate fractions by electron microscopy. Activity was found in the endoplasmic reticulum, on the inside of the inner mitochondrial membrane and on both leaflets of the nuclear membrane. Reaction product was found in the postsynaptic density area of most synapses. The reaction product tended to be more prominent in the presence of fluoride. A synaptosome-rich fraction was shown to have NE stimulated AC activity which was blocked in vitro by both a alpha- and an beta-blocker and in vivo by propranolol.

Adenylyl Cyclases↗
PubMed1969

Energized configurations of heart mitochondria in situ.

Changes in the configurational state of the cristal membranes of rat heart mitochondria within the living cell can be induced by imposing energizing conditions. An exact correlation has been established between the configurational states of the cristal membrane and the energy states of the mitochondrion. The configurational changes observed in mitochondria in situ are comparable to those established for beef heart mitochondria in vitro and are consistent with the postulate of the conformational basis of energy transductions in membrane systems. The formation of paracrystalline arrays is one of the noteworthy features of configurational changes of mitochondria in situ.

Animals↗
PubMedDate not supplied

The effects of MK-801, ifenprodil, JO 1784, JO 1994 and JO 1997 on PK 11195 receptor binding, nitric oxide synthase (NO synthase) activity and infarct volume in a mouse model of focal cerebral ischaemia.

Middle cerebral artery occlusion (MCAO) is a widely used surgical procedure for inducing focal cortical ischaemia in mice. In the present study, all experiments were performed on 4-week-old, male Swiss mice (OF-1 Iffa Credo, France), 20-25 g at the time of surgery. Sham-operated mice were subjected to simple exposure of the middle cerebral artery. Mice were injected with either MK-801, ifenprodil, JO 1784, JO 1994 or JO 1997 at the following time points after surgery; 5, 15, 45 min and 3, 6, 24, 30, 48 and 54 h. Mice were sacrificed 72 h after surgery and both ipsilateral and contralateral cortices were dissected in their entirety, weighed, and assayed for [3H]PK 11195 binding while the brain-stem and cerebellum were assayed for nitric oxide synthase (NO synthase) activity. In a separate experiment the area of ischaemic damage was determined planimetrically by means of an image analysis system. Coagulation of the middle cerebral artery induced a marked enhancement of the ipsilateral cortical omega 3 peripheral-type benzodiazepine binding site (PTBB'S) densities, an increase in NO synthase activity in the brain-stem and cerebellum, and an increase in the cortical infarct area. MK-801, ifenprodil, JO 1784, JO 1994 and JO 1997 demonstrated comparable neuroprotective effects on all three indices of cortical damage. A down-regulation of cortical omega 3 peripheral-type benzodiazepine binding site (PTBB'S) densities and a decrease in NOS activity occurred following pharmacological intervention. In contrast to JO 1784, JO 1994 and JO 1997 have a bimodal effect on omega 3 PTBB'S densities.

Animals↗
PubMedDate not supplied

The major components of human energy balance during chronic beta-adrenergic blockade.

PURPOSE: The authors compare the major components of energy balance--dietary food intake, resting metabolic rate, and physical energy expenditure--in patients receiving beta-blocking medications and healthy controls. METHODS: The authors recruited subjects who were receiving beta-blocking agents (n = 22) from local hospitals and clinics. Twenty-two healthy controls were matched to each patient based on age, weight, and gender. Resting metabolic rates were determined using indirect calorimetry. Three-day dietary intakes and physical activity assessments were analyzed. RESULTS: There were no between-group differences in calories ingested or self-reported physical activity patterns. However, resting metabolic rates were lower in the beta-blocked subjects (beta-blocked = 1,541 +/- 464 kcals/day; controls = 1,817 +/- 426 kcals/day; P < 0.05). CONCLUSIONS: beta-adrenergic blockade causes a reduction in resting metabolic rate. Therefore, beta-blocked individuals should increase physical activity, decrease dietary intake, or both to maintain daily energy balance and prevent weight gain that accompanies a reduction in metabolic rate.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Tumor effects on gluconeogenesis in the isolated perfused rat liver.

Alterations in metabolism in the tumor-bearing host can be explained by: 1) alterations of metabolic processes in the tumor itself, and/or 2) tumor effects on host metabolism. Tumor effects on host liver metabolism were studied using an isolated perfused rat liver preparation. The livers of fasted female Lewis Wistar rats with and without transplanted subcutaneous mammary tumors were perfused for 1 hr with medium containing 5 mM glucose and physiological levels of amino acids. The rate of gluconeogenesis, as measured by conversion of 14C-lactate to 14C-glucose, showed a significant increase in the rate of glucose production from lactate in tumor-bearing rats (2.40 vs 2.00 mumol/min/100 gm). Hepatic glycogen and 14C-glycogen content were not significantly different between the two groups. In order to evaluate whether this tumor model exhibits characteristic changes in metabolism previously reported in other animal tumor models, serum lactate, triglyceride, glucose, and blood urea nitrogen were measured in non-perfused animals. The serum concentration of lactate and triglycerides were significantly higher in tumor-bearing rats (0.9 mM vs 2.7 mM lactate; 244 mg % vs 365.5 mg % triglycerides). Serum glucose and blood urea nitrogen were not significantly different in the two groups. An effect of tumor on host energy metabolism and serum metabolite levels is demonstrated. A method for the study of host-tumor metabolic interactions is described.

Animals↗