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Biomedical subjects

Brenda J Smith

Publications and source records attributed to Brenda J Smith.

11 recordsLinked to original sources
PubMed2007

Deficits in free recall persist in Asperger's syndrome despite training in the use of list-appropriate learning strategies.

Free recall in adults with Asperger's Syndrome (AS) was compared with that in matched controls in an experiment including semantically similar, phonologically similar and unrelated word lists. Without supportive instructions, adults with AS were significantly impaired in their recall of phonologically and semantically related lists, but not unrelated lists. Even when trained to make use at study of the relations among the words, the adults with AS recalled fewer words than the control group. Participants rehearsed the study lists out loud and the rehearsal data was analysed. Despite a very slight trend for adults with AS to engage in less elaborative rehearsal and more rote rehearsal, their rehearsal did not differ significantly from that of controls.

Analysis of Variance↗
PubMed2006

Soy moderately improves microstructural properties without affecting bone mass in an ovariectomized rat model of osteoporosis.

Soy protein is reported to prevent bone loss in both women and rat models of osteoporosis. However, the role of soy isoflavones on the trabecular microarchitectural properties needs to be explored. In the present study, we examined whether soy protein with graded doses of isoflavones reverses loss of bone mineral density (BMD), bone mineral content (BMC), and trabecular microstructure in an ovariectomized (Ovx) osteopenic rat model. Seventy-eight 9-m old female Sprague-Dawley rats were either sham-operated (Sham; 1 group) or Ovx (5 groups) and fed a semi-purified casein-based diet. After 90 days, the occurrence of bone loss was confirmed using dual energy X-ray absorptiometry. Thereafter, rats were assigned to the following treatments: Sham, Ovx (control), Ovx + 17beta-estradiol (E(2); 10 microg/kg body wt. twice per week), Ovx + soy protein depleted of isoflavones (Soy-; 0.06 mg isoflavones/g protein), Ovx + soy protein with normal isoflavone content (Soy; 3.55 mg isoflavones/g protein), and Ovx + isoflavone-enriched soy protein (Soy+; 7.10 mg isoflavones/g protein). After 125 days of treatment, rats were euthanized, and tibia and lumbar bones were collected for the assessment of BMD, BMC, and trabecular microarchitectural properties using X-ray microcomputed tomography. None of the treatments had an effect on BMD or microarchitectural properties of the lumbar vertebra. However, Soy treatment significantly increased tibial BMC and BMD by 10% and 4.5% compared with Ovx control, but the increase in BMD was not enough to reach the BMD levels of the Sham control group. The Soy+ diet positively affected the tibial architectural properties including trabecular thickness, separation, and number. In summary, our findings suggest that soy protein does not restore bone loss in osteopenic rats; however, higher doses of isoflavones may be required to reverse the loss of tibial microstructural properties.

Absorptiometry, Photon↗
PubMed2005

One year soy protein supplementation has positive effects on bone formation markers but not bone density in postmenopausal women.

BACKGROUND: Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women. METHODS: Eighty-seven eligible postmenopausal women were randomly assigned to consume soy or control foods daily for one year. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, lumbar (L1-L4), and total hip were measured using dual energy x-ray absorptiometry at baseline and after one year. Blood and urine markers of bone metabolism were also assessed. RESULTS AND DISCUSSION: Sixty-two subjects completed the one-year long study. Whole body and lumbar BMD and BMC were significantly decreased in both the soy and control groups. However, there were no significant changes in total hip BMD and BMC irrespective of treatment. Both treatments positively affected markers of bone formation as indicated by increased serum bone-specific alkaline phosphatase (BSAP) activity, insulin-like growth factor-I (IGF-I), and osteocalcin (BSAP: 27.8 and 25.8%, IGF-I: 12.8 and 26.3%, osteocalcin: 95.2 and 103.4% for control and soy groups, respectively). Neither of the protein supplements had any effect on urinary deoxypyridinoline excretion, a marker of bone resorption. CONCLUSION: Our findings suggest that although one year supplementation of 25 g protein per se positively modulated markers of bone formation, this amount of protein was unable to prevent lumbar and whole body bone loss in postmenopausal women.

Absorptiometry, Photon↗
PubMed2005

Ipriflavone modulates IGF-I but is unable to restore bone in rats.

Previously it has been reported that ipriflavone can prevent bone loss in ovarian hormone deficient rats. The present study evaluated whether ipriflavone was able to restore bone mass in osteopenic ovariectomized rats. Seventy-two, 90 day-old Sprague-Dawley rats were divided into six groups (sham two groups; ovariectomized four groups). Thirty-five days from the date of surgery, one sham and one ovx group were killed to verify the occurrence of bone loss. The remaining four groups were sham, ovx, ovx + ipriflavone (100 mg[sol ]kg body weight per day), or ovx + 17beta-estradiol (10 microg[sol ]kg body weight daily) for a period of 65 days. Ipriflavone was ineffective in restoring bone density and unlike estrogen did not prevent bone resorption as evidenced by increased (p < 0.05) urinary excretion of hydroxyproline and serum tartrate-resistant acid phosphatase activity. Ipriflavone increased (p < 0.05) the expression of IGF-I in the femur. These observations suggest that higher doses of ipriflavone or longer-term studies may be necessary to restore bone mass.

Animals↗
PubMed2005

[1,2-13C2]-D-glucose profiles of the serum, liver, pancreas, and DMBA-induced pancreatic tumors of rats.

OBJECTIVES: In vitro stable isotope glucose tracer studies indicate that undifferentiated cells of the pancreas use glucose primarily through the nonoxidative reactions of the pentose cycle for nucleic acid ribose synthesis, whereas normal or less transformed cells primarily use the oxidative branch of the cycle. METHODS: The pancreatic heads of 4 groups (5/group) of male rats were implanted with time-release pellets designed to deliver placebo or 7,12-dimethylbenzanthracene (DMBA) at 11, 33, or 56 mg/d. Four weeks after pancreatic exposure to DMBA, [1,2-C2]-D-glucose tracer (1 g/kg) was injected intraperitoneally followed by sera collection at 1 and 2 hours and harvest of tumors, adjacent pancreatic tissue, and sera at 3 hours. RESULTS: Tumors (2-9 mm) were found across DMBA groups, with the largest in the high-dose group (> or =5 mm). Selective monitoring by gas chromatography-mass spectrometry of the doubly-labeled [1,2-C2]-D-ribose of RNA, which requires nonoxidative synthesis in the pentose cycle, showed a 2.8-, 2.9-, and 5.7-fold increase in pancreatic tumors. Liver and adjacent pancreas preferentially produced [1-C1]-D-ribose through the oxidative reactions of the cycle. Tumor-bearing animals also cleared and recycled tracer glucose at a faster rate. CONCLUSIONS: Simultaneous selective positional ion monitoring of C-labeled metabolites and their mass isotopomers in tissues and blood opens new avenues for the early detection and response to therapy testing of pancreatic cancer using GC-MS and/or magnetic resonance imaging-based methods. This study emphasizes the benefits of stable isotope-based dynamic metabolic profiling, when applied in vivo, and the several advantages it offers to positron emission tomography.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2004

Flaxseed reduces plasma cholesterol and atherosclerotic lesion formation in ovariectomized Golden Syrian hamsters.

BACKGROUND: Dietary modification contributes significantly in reducing cardiovascular disease (CVD) risk factors including lowering cholesterol and atherosclerosis. The purpose of this study was to investigate the effects of flaxseed, a rich source of lignans, alpha-linolenic acid and soluble fiber mucilage, on the prevention of ovariectomy-induced rise in total cholesterol and atherosclerotic lesions. METHODS: Seventy-two 6-month-old female Golden Syrian hamsters were either ovariectomized (ovx) or sham-operated (sham) and randomly assigned to six groups (n = 12): sham, ovx, or ovx plus either 17beta-estradiol (E(2), 10 microg/kg body weight) or semi-purified diet adjusted for macronutrients and fiber to contain one of the three doses of flaxseed (7.5, 15, or 22.5%) for 120 days. RESULTS: Ovariectomy significantly elevated plasma total-, HDL-, and free-cholesterol concentrations. Similar to estrogen, all doses of flaxseed were effective in preventing the ovx-induced rise in plasma total cholesterol. Triglyceride concentrations were significantly higher in the flax-fed hamsters. There were no significant differences in plasma non-HDL- and esterified-cholesterol among the treatment groups. Ovariectomy also increased the number of hamsters with lesions and the aortic fatty streak area. All three doses of flaxseed reduced the fatty streak area and the incidence of lesions to levels similar to the sham group. CONCLUSION: The findings of this study show that flaxseed is beneficial in reducing plasma cholesterol and plaque formation induced by ovarian hormone deficiency.

Animals↗
PubMed2003

Soy protein has a greater effect on bone in postmenopausal women not on hormone replacement therapy, as evidenced by reducing bone resorption and urinary calcium excretion.

Recent reports suggest that soy protein may reduce the risk of osteoporosis in peri- and postmenopausal women. The objective of this study was to examine whether soy supplementation exerts beneficial effects on serum and urinary biomarkers of bone metabolism in postmenopausal women, regardless of whether or not they are on hormone replacement therapy (HRT). A total of 71 women were randomly assigned to either soy protein (SP) or milk-based protein (MBP), 40 g daily for 3 months, in a double-blind parallel design. Forty-two women completed the study (20 on SP and 22 on MBP). Overall, both protein supplements positively influenced serum IGF-I, known to correlate with bone formation. However, SP had a more pronounced effect on IGF-I than MBP. Urinary deoxypyridinoline (Dpd) excretion, a specific biomarker of bone resorption, was significantly reduced by SP, but not by MBP when all women were included. Furthermore, women on MBP experienced a 33% increase in urinary calcium excretion, whereas SP did not have such an effect. To evaluate whether SP affects women differently on the basis of their HRT status, data from women on HRT (n = 22) and those not on HRT (n = 20) were analyzed separately. The subanalysis of the data indicated that SP had the greatest impact on serum IGF-I (an increase of 97%) in the women not on HRT. The changes in urinary Dpd due to SP were only observed in women not on HRT, indicating that the overall decrease in Dpd occurred with SP in the absence of HRT. These results indicate that soy protein may positively influence bone and calcium homeostasis in postmenopausal women, particularly those not on HRT.

Bone Resorption↗
PubMed2003

Gene activity associated with cancers treated by surgical oncologists.

A significant component of the general surgeon's practice is treatment of cancer that most commonly involves breast, colorectal, pancreas, and hepatic surgeries. The prognosis for these patients is largely dependent upon the stage of the disease at the time of diagnosis. There is convincing evidence that the induction and progression of cancer occurs when the function of genes that regulate cell proliferation, cell death and DNA repair becomes altered. These molecular disturbances result from ongoing, tumor-promoting activity long before symptoms of the disease become apparent. The role of many genes and the extent of their involvement in this deleterious, molecular process is unique to the organ. However, the tumor suppressor genes p53 and p16, the oncogene c-myc, and the inflammation-associated enzyme COX-2 are implicated in all four of the tumors. The roles of the oncogenes ras and HER-2/erbB-2/neu are significant in all of the tumors except hepatocellular carcinoma. The systematic establishment of a comprehensive data base relating gene expression activity to the initiation and development of cancer will provide molecular markers for detection and targets for treatment. This overview presents the current status of information associating gene expression activity with cancers typically encountered by general surgeons.

Breast Neoplasms↗
PubMed2002

Skeletal unloading and dietary copper depletion are detrimental to bone quality of mature rats.

This study was designed to examine the skeletal response to copper depletion and mechanical unloading in mature animals. In a 2 x 2 experimental design, 5.5-mo-old male Sprague-Dawley rats (n = 36) consumed either the control (AIN-93M) or Cu-depletion ((-)Cu) diet beginning 21 d before suspension and throughout the remainder of the study. Half of the rats in each dietary treatment group were either tail-suspended (TS) or kept ambulatory (AMB) for 28 d. Lower bone mineral densities (BMD) of 5th lumbar vertebra (L5) (P < 0.05) and femur were observed with (-)Cu and TS, but no differences were noted in the BMD of the humerus. Mechanical strength in the femur and vertebra decreased in response to TS, but were unaffected by copper depletion. Urinary deoxypyridinoline, an index of bone resorption, was significantly greater in TS rats, but unaltered by (-)Cu. No changes in serum or bone alkaline phosphatase activity, an indicator of bone formation, were observed. Our findings suggest that TS and (-)Cu decreased BMD in unloaded femur and vertebra but had no effect on normally loaded humerus. Bone loss with TS appeared to be related to accelerated bone resorption. Alterations in bone metabolism and bone mechanical properties in the mature skeleton resulting from (-)Cu warrant further investigation.

Alkaline Phosphatase↗
PubMed2002

Soy protein supplementation increases serum insulin-like growth factor-I in young and old men but does not affect markers of bone metabolism.

Recent studies suggest that soy protein (SP) protects bone in women; however, its effects on bone metabolism in men have not been investigated. Healthy men (59.2 +/- 17.6 y) were assigned to consume 40 g of either SP or milk-based protein (MP) daily for 3 mo in a double-blind, randomized, controlled, parallel design. Serum insulin-like growth factor-I (IGF-I), which is associated with higher rates of bone formation, was greater (P < 0.01) in men supplemented with SP than in those consuming MP. Serum alkaline phosphatase and bone-specific alkaline phosphatase activities, markers of bone formation, and urinary deoxypyridinoline excretion, a specific marker of bone resorption, were not different between the SP and MP groups. Furthermore, because substantial reductions in bone density occur in men at approximately 65 y of age, data were analyzed separately for men >/=65 y and those <65 y of age. The response to protein supplementation was consistent in the two age groups. The effects of SP on serum IGF-I levels suggest that SP may positively influence bone in men. Longer-duration studies examining the effects of SP or its isoflavones on bone turnover and bone mineral density and content in men are warranted.

Adult↗