Specialist and Patient Perspectives on Strategies to Improve Cardiovascular Disease Prevention Among Persons Living with Psoriatic Disease

Background

Psoriasis is an immune-mediated disease associated with excess risk for cardiovascular disease (CVD). Guidelines recognize psoriasis as a CVD risk enhancer; however, psoriasis patients often do not have CVD risk factors identified nor managed.

Objective

This study examines strategies to improve CVD prevention care from the perspective of dermatologists and patients with psoriasis.

Methods

Qualitative interviews were conducted using the Consolidated Framework for Implementation Research to examine the perspectives of physicians (N = 16) and patients with psoriatic disease (N = 16) on barriers/facilitators to CVD prevention. Interviews were transcribed and coded using an integrated approach designed to enhance reliability and validity using NVivo software.

Results

We found three major themes suggesting areas to target for the future: (1) Appropriateness: perceptions of whether CVD care should be deployed in this setting by both clinicians and patients, (2) Feasibility: whether CVD prevention care could be integrated into the current structure of specialist practice, and (3) Care Coordination: an interest by all parties to better integrate a team approach in CVD preventative care to reduce duplicative efforts, work practically in an already existing system rather than reinventing the wheel, and progress with the patients' best interests in mind.

Conclusions

These findings will inform the design of a clinical trial comparing the effectiveness of specialist clinician implementation of CVD guideline-based prevention care in patients with psoriasis. Ultimately, this study aims to increase the lifespan and health of patients living with psoriatic disease by decreasing barriers to their receiving appropriate CVD prevention care.

Association between Body Condition Score and Cancer Prognosis in Dogs with Lymphoma and Osteosarcoma

Background

In humans and rodents obesity appears to promote some cancers by increasing incidence, tumor aggressiveness, recurrence, and fatality. However, the relationship between obesity and cancer in dogs has not been thoroughly evaluated.

Hypothesis/Objectives

Whether body condition score (BCS) at the time of lymphoma (LSA) or osteosarcoma (OSA) diagnosis in dogs is predictive of survival time (ST) or progression‐free interval (PFI). We hypothesized that an overweight body state at the time of cancer diagnosis would be associated with negative outcomes.

Animals

Dogs with LSA (n = 270) and OSA (n = 54) diagnosed and treated between 2000 and 2010.

Methods

Retrospective case review. Signalment, body weight, BCS, cancer diagnosis and treatment, relevant clinicopathologic values, and survival data were collected. Dogs were grouped by BCS (underweight, ideal, and overweight) and ST and PFI were compared.

Results

Overall, 5.5% of dogs were underweight, 54.0% were ideal weight, and 40.4% were overweight at diagnosis. Underweight dogs with LSA had shorter ST (P = .017) than ideal or overweight dogs. BCS was not associated with ST for OSA (P = .474). Progression‐free interval did not differ among BCS categories for either cancer.

Conclusions and Clinical Importance

Obesity was not associated with adverse outcomes among dogs with LSA or OSA in this retrospective study; however, being underweight at the time of diagnosis of LSA was associated with shorter survival. More research is needed to elucidate the relationship between excessive body weight and cancer development and progression in dogs.

Single nucleotide polymorphisms in uracil-processing genes, intake of one-carbon nutrients and breast cancer risk

BACKGROUND/OBJECTIVES

The misincorporation of uracil into DNA leads to genomic instability. In a previous study, some of us identified four common single nucleotide polymorphisms (SNPs) in uracil-processing genes (rs2029166 and rs7296239 in SMUG1, rs34259 in UNG and rs4775748 in DUT) that were associated with significantly altered levels of uracil in human DNA. We investigated whether any of these SNPs are associated with an altered risk of developing breast cancer and if one-carbon nutrients intake can modify their effects.

SUBJECTS/METHODS

We genotyped the four SNPs in 1077 cases of incident breast cancer and 1910 age and race-matched controls in the Western New York Exposures and Breast Cancer (WEB) Study and examined associations with breast cancer risk and interactions with intake of folate, vitamins B6 and B12.

RESULTS

After adjustment for known risk factors for breast cancer, there was increased risk of breast cancer among postmenopausal women who were heterozygous for either of the two SMUG1 SNPs (odds ratio (OR) 1.29, 95% confidence interval (CI) 1.07-1.56) and OR 1.29, 95% CI 1.07-1.55, respectively). Among premenopausal women, increased risk associated with the SMUG1 rs2029166 genotype was limited to those with low folate intake. There were no other interactions with vitamins B(6) or B(12) intake.

CONCLUSIONS

Our study suggests that the four selected SNPs are not robust determinants of breast cancer risk, but that the two SNPs in SMUG1 might modestly alter the risk of breast cancer. However, the increase in risk among heterozygotes in the two SNPs in SMUG1, which is thought to be the most active glycosylase in vivo, raises the possibility that subtle 'heterosis' effects on cancer risk might be produced by these SNPs.

Analysis of the outcome in male and female patients using a unisex total knee replacement system

Gender-specific total knee replacement has generated much interest recently. We reviewed 1970 Sigma knees implanted in 920 women and 592 men with a mean age of 69.7 years. At a mean follow-up of 7.3 years (minimum, five years), we found minimal differences in the outcome between genders. At the final follow-up, men had a higher overall Knee Society score and more osteolysis (3.8% vs 1.1%). However, there were no significant differences between men and women in terms of complications or improvements in knee function, pain score or range of movement. The estimated ten-year survivorship was 97% in women and 98% in men (p = 0.96). We concluded that there was little difference in outcome between the genders treated by a modern unisex design of total knee replacement in this large multicentre study.

Midterm survival of a contemporary modular total knee replacement

This retrospective study evaluated the midterm clinical and radiographic outcomes of a second-generation total knee replacement system. In a multicentre consecutive series of 1512 patients, 1970 knees were treated with the PFC Sigma knee system (Depuy, Warsaw, Indiana). The patients were reviewed for functional outcome, and underwent independent radiographic evaluation at a mean follow-up of 7.3 years (5 to 10). A total of 40 knees (2%) required revision, 17 (0.9%) for infection. The incidence of osteolysis was 2.2%. The ten-year survival with revision for any cause other than infection as the endpoint was 97.2% (95% CI 95.4 to 99.1).

The PFC Sigma knee system appears to provide excellent results in the medium term.

23 NEONATAL PHYSIOLOGICAL STATUS OF CLONED AND CONTROL CALVES

Health problems and mortality rates of cloned calves are major limitations of cloning technology and represent substantial economic losses as well as justifiable animal health and welfare concerns. The objectives of this study were to compare neonatal viability and physiological status of cloned and control calves. Cloned (Holstein, n = 5; Hereford, n = 3) and control (embryo transfer: Holstein, n = 3; Hereford, n = 3) calves were carried in the same group of Hereford × Angus crossbred recipient dams and were delivered by Cesarean section at term (Days 273–280) following induced labor. Additional calves (Holstein, n = 3; Hereford, n = 2) resulting from AI and delivered vaginally by their natural dams (Days 269–279) following spontaneous initiation of parturition were included as normal controls to evaluate the effects of the induction procedure. Physical evaluations and measurements of blood biochemistry (19 parameters), gases and electrolytes (9 parameters), and complete blood counts (18 parameters) were performed within 10 min of birth and at 1, 6, 12, 18, 24, 36, and 48 h after birth. Cloned calves were observed with increased occurrence of flexural limb deformities (4/8 clones, 0/9 controls; P < 0.05) and developmental delays of physical adjustment parameters such as time to suckle and stand (5/8 clones requiring >3 h; P < 0.05). Cloned calves were more variable than, but not different from, controls for most blood parameters measured. Compared with controls, at birth clones exhibited reduced red blood cell counts (6.8 and 8.6 × 109 cells/mL, clones and controls, respectively; P < 0.01), plasma bicarbonate (23.1 vs. 26.2 mmol/L; P < 0.05), and plasma glucose (39.4 vs. 73.6 mg/dL; P < 0.05). Blood urea nitrogen concentrations in clones tended to be elevated beginning 24 h after birth and were significantly greater than those in controls by 48 h (13.4 vs. 7.4 mg/dL; P < 0.01). Echocardiographic measurements at 24 h of age varied between groups (Table 1) and were indicative of circulatory abnormalities likely originating in utero for clones. The results of this study identified the physiological differences between clones and controls at birth and may be useful in the development of clinical-care protocols to maximize the health and survival of cloned calves. Table 1. Echocardiographic characteristics of cloned and control calves

The National Vitamin A Supplementation Program and Subclinical Vitamin A Deficiency among Preschool Children in the Philippines

The prevalence of vitamin A deficiency (serum retinol [SR] < 20 μg/dl) in children from one to five years of age in the Philippines rose from 35.8% to 38% between 1993 and 1998, despite a twice-yearly universal vitamin A capsule distribution program. The Philippines 1998 National Nutrition Survey, with one-time SR measurements from 11,620 children from one to four years of age, collected over an eight-month period from one month to more than six months after distribution of vitamin A capsules, was an opportunity to examine the impact of the program on the children's vitamin A status, using post hoc analysis. Overall, a detectable impact of vitamin A capsules on SR was limited to groups with the highest prevalence of vitamin A deficiency and lasted up to four months after dose administration. In highly urban cities in Visayas, where very high prevalences of deficient SR (SR < 10 μg/dl) were found, the prevalence of deficient SR was reduced from 27% to 9% one to two months after distribution of vitamin A capsules, and to 16% at three to four months. In Mindanao, a statistically significant reduction from 38% to 32% was seen in the prevalence of deficient to low SR (SR < 20 μg/dl) one to four months after distribution of vitamin A capsules. There was no overall reduction in the prevalence of vitamin A deficiency or deficient and low SR (SR < 20 μg/dl) in Luzon, but a significant interaction with stunting was observed in Luzon non-highly urbanized cities. Two aspects are of concern. First, the magnitude of the effect of high-dose vitamin A capsules on SR, and hence on the extent of reduction in deficiency, is limited. Second, the effect does not persist for six months, which is the interval between doses. Thus there is no decrease in the prevalence of deficiency over time. With more frequent dosing (especially to those most deficient in SR), a progressive reduction in vitamin A deficiency could, however, be expected; this hypothesis could be tested. The policy implication arising from these results is that a shift in resources is warranted. In areas of low prevalence of vitamin A deficiency, distribution of vitamin A capsules should be targeted to stunted children. In areas of high prevalence, vitamin A capsules should be distributed to children one to five years old at least three times a year.

Evidence of increased substrate availability to in vitro-derived bovine foetuses and association with accelerated conceptus growth

Changes in placental development have been associated with foetal abnormalities afterin vitroembryo manipulations. This study was designed to investigate bovine conceptus development and substrate levels in plasma and fluids inin vivo- andin vitro-produced (IVP) concepti and neonates.In vivo-produced and IVP embryos were derived by established embryo production procedures. Pregnant animals from both groups were slaughtered on days 90 or 180 of gestation, or allowed to go to term. Conceptus and neonatal physical traits were recorded; foetal, maternal and neonatal blood, and foetal fluids were collected for the determination of blood and fluid chemistry, and glucose, fructose and lactate concentrations. Placental transcripts for specific glucose transporters were determined by quantitative RT-PCR. No significant differences in uterine and conceptus traits were observed between groups on day 90. On day 180, larger uterine, placental and foetal weights, and an increase in placental gross surface area (SA) in IVP pregnancies were associated with increased glucose and fructose accumulation in foetal plasma and associated fluids, with no differences in the expression of components of the glucose transporter system. Therefore, the enlarged placental SA in IVP pregnancies suggests an increase in substrate uptake and transport capacity. Newborn IVP calves displayed higher birth weights and plasma fructose concentrations soon after birth, findings which appeared to be associated with clinical and metabolic distress. Our results indicated larger concepti and increased placental fructogenic capacity in mid- to late IVP pregnancies, features which appeared to be associated with an enhanced substrate supply, potentially glucose, to the conceptus.

Activation of methionine synthase by insulin-like growth factor-1 and dopamine: a target for neurodevelopmental toxins and thimerosal

Methylation events play a critical role in the ability of growth factors to promote normal development. Neurodevelopmental toxins, such as ethanol and heavy metals, interrupt growth factor signaling, raising the possibility that they might exert adverse effects on methylation. We found that insulin-like growth factor-1 (IGF-1)- and dopamine-stimulated methionine synthase (MS) activity and folate-dependent methylation of phospholipids in SH-SY5Y human neuroblastoma cells, via a PI3-kinase- and MAP-kinase-dependent mechanism. The stimulation of this pathway increased DNA methylation, while its inhibition increased methylation-sensitive gene expression. Ethanol potently interfered with IGF-1 activation of MS and blocked its effect on DNA methylation, whereas it did not inhibit the effects of dopamine. Metal ions potently affected IGF-1 and dopamine-stimulated MS activity, as well as folate-dependent phospholipid methylation: Cu(2+) promoted enzyme activity and methylation, while Cu(+), Pb(2+), Hg(2+) and Al(3+) were inhibitory. The ethylmercury-containing preservative thimerosal inhibited both IGF-1- and dopamine-stimulated methylation with an IC(50) of 1 nM and eliminated MS activity. Our findings outline a novel growth factor signaling pathway that regulates MS activity and thereby modulates methylation reactions, including DNA methylation. The potent inhibition of this pathway by ethanol, lead, mercury, aluminum and thimerosal suggests that it may be an important target of neurodevelopmental toxins.

Iodine fortification is related to increased weight-for-age and birthweight in children in Asia

Severe iodine deficiency causes stunting and mental retardation in utero, but the relation between mild deficiency and child growth is not well known. The use of iodated salt in relation to anthropometric data was examined from recent survey data. After potential confounding factors had been controlled for, significant associations were seen in Bangladesh, India, Nepal, and Sri Lanka. The use of iodated salt was related to increased weight-for-age and mid-upper-arm circumference, most strongly in the second year of life, mainly affecting soft tissue (thinness). The relation with weight-for-age was greater among children of mothers with lower body mass index. The use of iodated salt was related to birthweight in Sri Lanka and in the Philippines, where iodized oil capsules given during pregnancy had a negative effect when used with high levels of iodine in salt. The associations generally were concentrated in large geographic areas, possibly because of interactions with other environmental factors (e.g., selenium and arsenic). The apparent growth response to iodine may reflect functional effects of mild deficiency, which is widespread, possibly including effects on brain development.

Early failures in total knee arthroplasty

Total knee arthroplasty is a predictable operation. Unfortunately, there is a subset of patients who do not do well and require revision surgery within the first 5 years. The purpose of the current study was to analyze the mechanisms of failure in patients who had revision surgery within 5 years of their index arthroplasty. Between 1986 and 1999, 440 patients with total knee arthroplasties were referred for revision surgery. An analysis of patients in whom the arthroplasties failed within 5 years of the index arthroplasty and the reasons for early failure were documented. Of the 440 patients who had revision surgery, 279 (63%) had revision surgery within 5 years of their index arthroplasty: 105 of the 279 patients with early failures (38%) had revision surgery because of infection; 74 (27%) had revision surgery because of instability; 37 (13%) had revision surgery because of failure of ingrowth of a porous-coated implant; 22 (8%) had revision surgery because of patellofemoral problems; and 21 (7%) had revision surgery because of wear or osteolysis. Only eight of the 279 patients with early failures (3%) had revision surgery because of aseptic loosening of a cemented implant. The remaining 12 patients had revision surgery because of miscellaneous problems. Host factors may prevent infection from ever being eradicated totally. The two other major patterns of failure in this series were failure of cementless fixation and instability. If all of the arthroplasties in the patients in this early failure group would have been cemented routinely and balanced carefully, the total number of early revisions would have decreased by approximately 40%, and the overall failures would have been reduced by 25%.

Acetabular labral tears in the athlete

Pathologic involvement of the acetabular labrum is an increasingly recognized phenomenon. Athletes involved in sports that require repetitive twisting or who suffer trauma to the hip are at risk of injury to the acetabular labrum. Injury mechanisms that include hyperextension, hyperflexion, or extremes of abduction place the labrum at particular risk. Symptoms may be acute in onset or, more commonly, insidious onset with persistence or escalation of symptoms. The orthopaedic surgeon evaluating patients with sports-related hip injuries needs to remain cognizant of intraarticular injuries within the hip and, in particular, injuries to the acetabular labrum. Further investigation is needed to fully define the functional importance of the acetabular labrum. Arthroscopic management has been successful in evaluation and management of acetabular labral tears.

Folate status among patients with non-small cell lung cancer: a case-control study

BACKGROUND AND OBJECTIVES

This case control study explored the purported inverse relationship between folate status and lung cancer development.

METHODS

Folate status of 46 postoperative non-small cell lung cancer (NSCLC) patients was compared to that of 44 non-cancer patients. Cancer patients had completed treatment > 3 months prior and had no evidence of cancer. Ineligibility criteria for all patients included (1) > 2 alcoholic drinks/day (2) ongoing tobacco use, or (3) folate supplementation > 400 microg/day.

RESULTS

No differences were found between groups in serum and RBC folate after adjustment for age and use of folate-interfering medications: geometric means (GM) x /geometric standard error (GSE): 7.9 ng/ml x /1.1 vs. 7.8 ng/ml x /1.1, respectively (P = 0.91) for serum folate; 264 ng/ml x /1.1 vs. 263 ng/ml x /1.1, respectively (P = 0.97) for RBC folate. Age- and creatinine-adjusted homocysteine was no different between groups: GM x /GSE: 9.4 micromol/L x /1.0 vs. 8.6 micromol/L x /1.0, respectively (P = 0.17). No difference were seen in folate intake. Frequencies of the homozygous genotype for the MTHFR polymorphism, an enzyme important in folate metabolism and associated with a reduced risk of other cancers, were no different.

CONCLUSIONS

This case control study does not support the hypothesis that low folate is an independent risk factor for NSCLC.

Colonic mucosal concentrations of folate are accurately predicted by blood measurements of folate status among individuals ingesting physiologic quantities of folate

Folate status is inversely related to the risk of colorectal cancer. Whether conventional blood measurements of folate status accurately reflect folate concentrations in the colorectal mucosa has been a controversial topic. This is an important issue because accurate measures of folate status in the colorectal mucosa are important for ascertaining the risk of colorectal cancer in epidemiological studies and for determining the effects of folate supplementation in clinical trials. We examined whether conventional blood measurements of folate and a more sensitive, inverse indicator of systemic folate status, serum homocysteine, accurately reflect folate concentrations in human colonic mucosa obtained by endoscopic biopsy. Study subjects (n = 20) were participants in a randomized trial that investigated the effect of folate supplementation (5 mg daily for 1 year) on provisional molecular markers of colon cancer. Blood samples and biopsies of normal rectosigmoid mucosa were obtained at baseline, at 6 months, and at 1 year. Serum, RBC, and colonic mucosal folate and serum homocysteine concentrations were determined. Colonic mucosal folate concentrations correlated directly with serum folate concentrators at each time point (r = 0.572-0.845; P < 0.015) and with RBC folate concentrations at 6 months and 1 year (r = 0.747-0.771; P < 0.001). Colonic mucosal folate concentrations correlated inversely with serum homocysteine concentrations at each time point (r = -0.622-0.666; P < 0.008). Systemic measures of folate status did not correlate with colonic mucosal folate concentrations among individuals receiving supplemental folate. Our observations indicate that colonic mucosal concentrations of folate may be predicted accurately by blood measurements of folate status only among individuals not ingesting supraphysiological quantities of folate.

Effects of folate supplementation on two provisional molecular markers of colon cancer: a prospective, randomized trial

OBJECTIVES

Dietary folate intake is inversely associated with the risk of colorectal cancer. This study investigated the effect of folate supplementation on genomic DNA methylation and DNA strand breaks in exons 5-8 of the p53 gene of the colonic mucosa, two provisional biomarkers of colon cancer.

METHODS

Twenty subjects with adenomas were randomized to receive either folate (5 mg/day) or placebo for 1 yr after polypectomy. At baseline, 6 months and 1 yr, systemic and colonic measures of folate status were determined, as were the biomarkers mentioned earlier.

RESULTS

Folate supplementation increased serum, red blood cell and colonic mucosal folate concentrations (p < 0.02). Folate supplementation also increased the extent of genomic DNA methylation at 6 months and 1 yr (p = 0.001), whereas placebo administration was associated with an increase in the extent of genomic DNA methylation only at 1 yr. Similarly, folate supplementation decreased the extent of p53 strand breaks in exons 5-8 at 6 months and 1 yr (p < 0.02), whereas placebo administration was associated with a decrease in the extent of p53 strand breaks only at 1 yr.

CONCLUSIONS

Both of these provisional biomarkers of colon cancer underwent accelerated improvement at 6 months with folate supplementation. However, these markers also improved with placebo at 1 yr. Therefore, potential confounding factors that seem to modulate these biomarkers need to be identified and corrected in order for these markers to serve as suitable surrogate endpoints in folate chemoprevention trials.

Articulating versus static spacers in revision total knee arthroplasty for sepsis. The Ranawat Award

Antibiotic laden spacer blocks frequently are used to treat an infected total knee arthroplasty. Static spacer blocks make exposure at reimplantation difficult secondary to quadriceps shortening. Unexpected bone loss attributable to migration of the spacer block also has been reported. To avoid these problems, a temporary articulating molded implant made of antibiotic cement was used in a consecutive series. The authors sought to determine whether its use would affect the reinfection rate, improve functional results, or prevent bone loss compared with static spacers. Twenty-five patients were treated with static nonarticulating spacers. Since 1996, 30 patients have been treated with tobramycin-laden articulating spacers. The knee arthroplasties in three patients treated with a static spacer became reinfected (12%). The knee arthroplasty in one patient with an articulating spacer became reinfected (7%). Fifteen of the 25 patients with static spacers had unexpected bone loss between stages. No appreciable bone loss could be measured in the patients who received articulating spacers. The average Hospital for Special Surgery score was 83 points in the patients with static spacers and 84 points for the patients with articulating spacers. Range of motion at final followup averaged 98 degrees in the patients who received static spacers and 105 degrees in the patients who received articulating spacers. Articulating spacers seem to facilitate reimplantation of infected total knee arthroplasty without additional risk of infection. Unexpected bone loss is no longer a concern with this two-stage technique. Articulating spacers offered no functional advantage over static spacers in this study group.

Effects of dietary folate on intestinal tumorigenesis in the apcMin mouse

Dietary folate appears to be inversely related to colorectal cancer risk. This study investigated the effects of dietary intervention with folate or the development of intestinal polyps in Min (Apc +/-) mice. Weanling Mil mice were fed diets containing 0, 2 (basal requirement), 8, or 20 mg folate/kg diet. At 3 and 6 months of dietary intervention, 50% of the mice from each group were sacrificed, and the small intestine and colon were analyzed for polyps and aberrant crypt foci (ACF). Serum folate concentrations accurately reflected dietary folate levels (P < 0.001). At 3 months no significant difference in the average number of total small intestinal polyps was observed among the four groups. However, increasing dietary folate levels significantly reduced the number of ileal, but not duodenal or jejunal, polyps in a dose-dependent manner (P-trend = 0.001); folate supplementation at 20 mg/kg diet was associated with a 68-78% reduction in the number of ileal polyps compared with the other three diets (P < 0.007). The number of ileal polyps was inversely correlated with serum folate concentrations (P = 0.03). At 3 months, increasing dietary folate levels significantly decreased the number of colonic ACF in a dose-dependent manner (P = 0.05); the control and two folate supplemented diets significantly reduced the number of colonic ACF by 75 100% compared with the folate-deficient diet (P < 0.04). The number of colonic ACF was inversely correlated with serum folate concentration (P = 0.05). No significant difference in the number of colonic adenoma was observed among the four groups at 3 months. At 6 months, no significant differences in the average number of total small intestinal, duodenal, and jejunal polyps, colonic adenomas, and colonic ACF wer observed among the four groups. However, the folate-deficient diet had 62-76% lower number of ileal polyps compared with the control and two folate-supplemented diets (P < 0.003). Serum folate concentrations, but not dietary folate levels, were directly correlated with the number of ilea polyps (P = 0.006). These data suggest that dietary folate supplementation suppresses the development of ileal polyps and colonic ACF in this model However, at later time points, folate supplementation appears to have an opposite effect on ileal polyps. These data generally support the role of folate in intestinal tumorigenesis suggested in epidemiological studies and chemical carcinogen animal models. Notwithstanding the limitations associated with this model, these data suggest that the optimal timing and dose of folate intervention need to be determined for safe and effective folate chemoprevention.

Genomic DNA hypomethylation, a characteristic of most cancers, is present in peripheral leukocytes of individuals who are homozygous for the C677T polymorphism in the methylenetetrahydrofolate reductase gene

DNA methylation is an epigenetic feature of DNA that influences cellular development and function, and aberrations of DNA methylation are a candidate mechanism for the development of cancer. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the synthesis of 5-methyltetrahydrofolate, the methyl donor for methionine synthesis and the precursor of S-adenosylmethionine. S-adenosylmethionine is the universal methyl donor for methylation reactions, including that of DNA methylation. In the present study, we investigated whether a common C677T mutation in the MTHFR gene, which results in reduced enzyme activity in vitro, affects genomic DNA methylation. We selected 9 subjects homozygous for the wild-type MTHFR and 10 subjects homozygous for the mutation (T/T). Genomic DNA methylation was determined by an established enzymatic assay that measures the capacity of DNA to accept methyl groups in vitro, which is inversely related to endogenous methylation. DNA from subjects with the T/T MTHFR genotype had a significantly higher methyl group acceptance capacity (12,615 +/- 1836 dpm/2 microg of DNA) compared with wild-type MTHFR (7843 +/- 1043 dpm/2 microg of DNA; P < 0.05), indicating DNA hypomethylation in the T/T genotype. Furthermore, DNA methylation was directly and significantly related to RBC folate concentrations in persons with the T/T genotype, but not in those with wild-type MTHFR. These data are consistent with prior observations, which suggest that the T/T genotype is associated with impaired MTHFR activity in vivo and that the cellular impact of this impairment is determined, in part, by folate status. The relationship of genomic DNA hypomethylation in persons with the T/T MTHFR genotype to the development of cancer remains to be defined.

Effects of dietary folate on DNA strand breaks within mutation-prone exons of the p53 gene in rat colon

BACKGROUND & AIMS

Diminished folate status has been observed to increase colorectal cancer risk. Folate plays an important role in DNA synthesis and repair. This study investigated the effects of dietary folate on DNA strand breaks in the p53 and Apc genes, and how these changes are related to steady-state levels of the corresponding transcripts.

METHODS

Three groups of rats were fed diets containing 0, 2 (basal requirement), or 8 mg folate/kg for 5 weeks. At each weekly time point, plasma and colonic mucosal folate concentrations were determined. Site-specific DNA strand breaks were assessed by semiquantitative PCR. Steady-state levels of messenger RNA were measured by semiquantitative RT-PCR.

RESULTS

Dietary folate deficiency produced progressive DNA strand breaks within exons 5-8 of the p53 gene in rat colon (P<0.02). Accumulation of strand breaks was not observed in other exons of the p53 gene, in the Apc and beta-actin genes, or at the genomic level. Folate supplementation at 4 times the basal requirement significantly increased p53 integrity compared with the basal and deficient diets (P<0.05). p53 integrity in exons 5-8 was significantly correlated with folate status (P<0.03). Dietary folate deprivation progressively decreased, whereas supplementation increased, steady-state levels of p53 transcript over 5 weeks (P<0.05). No such changes were observed for the Apc gene. Steady-state levels of p53 transcript were significantly correlated with folate status and p53 integrity in exons 5-8 (P<0.002).

CONCLUSIONS

These data provide a plausible mechanism by which folate deficiency promotes, and folate supplementation suppresses, colorectal carcinogenesis.

Effect of chronic alcohol consumption on total plasma homocysteine level in rats

BACKGROUND

Chronic alcoholism in humans is associated with the development of hyperhomocysteinemia, the mechanism of which remains unclear. Among the causes of hyperhomocysteinemia is depletion of folate, vitamin B12, or vitamin B6. Population-based studies indicate that folate is the strongest vitamin determinant of hyperhomocysteinemia and, in most settings, folate supplementation effectively lowers elevated homocysteine levels. However, it is not clear whether folate deficiency is the cause of alcohol-related hyperhomocysteinemia.

METHODS

In the present study, 10 male Sprague Dawley rats were fed ethanol-containing Lieber-DeCarli diets with 13 mg of folic acid per kilogram of diet. This represents a folate intake more than 20 times the basal requirement. Ethanol represented 36% of total energy, which yielded a concentration of 6.2% (vol/vol). The same number of rats were pair-fed with isocaloric control diets that contained an identical level of folate in which ethanol was entirely replaced by maltodextrin.

RESULTS

At the end of 4 weeks, alcohol-fed rats did not show any significant reduction in plasma or hepatic folate concentrations, plasma pyridoxal-5'-phosphate concentration, or plasma vitamin B12 concentration. On the other hand, alcohol-fed rats were significantly hyperhomocysteinemic (17.24 +/- 4.63 micromol/liter,p < 0.01) compared to the nonalcohol group (10.73 +/- 2.76 micromol/liter). Alcohol-fed rats also had a significantly lower hepatic S-adenosylmethionine and higher hepatic S-adenosylhomocysteine levels.

CONCLUSIONS

Chronic alcohol consumption produces hyperhomocysteinemia by a mechanism that is related to interference with one-carbon metabolism, and not through vitamin depletion.

Folate and carcinogenesis: an integrated scheme

Collectively, the evidence from epidemiologic, animal and human studies strongly suggests that folate status modulates the risk of developing cancers in selected tissues, the most notable of which is the colorectum. Folate depletion appears to enhance carcinogenesis whereas folate supplementation above what is presently considered to be the basal requirement appears to convey a protective effect. The means by which this modulation of cancer risk is mediated is not known with certainty, but there are several plausible mechanisms which have been described. Folate plays a major role in the formation of S-adenosylmethionine, the universal methyl donor, as well as in the formation of purine and thymidine synthesis for DNA and RNA. Therefore, most mechanistic studies performed to date have focused on alterations in DNA methylation, disruption of DNA integrity and disruption of DNA repair, all of which have been observed with folate depletion. These aberrations in DNA are believed to enhance carcinogenesis by altering the expression of critical tumor suppressor genes and proto-oncogenes. Recently, the role of a common polymorphism of the methylenetetrahydrofolate reductase gene has been highlighted as well. This review presents those mechanisms which are the most likely candidates to explain folate's effects and it proposes an integrated scheme to explain how these mechanisms might interact.

The effect of dietary folate on Apc and p53 mutations in the dimethylhydrazine rat model of colorectal cancer

Dietary inadequacy of folate enhances and folate supplementation suppresses colorectal carcinogenesis in the dimethylhydrazine rat model. Folate is an essential factor for DNA methylation and the de novo biosynthesis of nucleotides, aberrations of which play important roles in mutagenesis. This study investigated whether the mutational hot spots of the Apc and p53 genes for human colorectal cancer are mutated in dimethylhydrazine-induced colorectal neoplasms and whether dietary folate can modulate mutations in these regions. Rats were fed diets containing 0, 2 (basal requirement), 8 or 40 mg folate/kg diet. Five weeks after diet initiation, dimethylhydrazine was injected weekly for 15 weeks. Mutations were determined by direct sequencing in 11 low and seven high grade dysplasias and 13 invasive adenocarcinomas. A total of six Apc mutations were found in four dysplastic and carcinomatous lesions: two in two low grade dysplasias, two in one high grade dysplasia and two in one adenocarcinoma. All mutations were single base substitutions, four of which were A:T-->G:C transitions. Five of the six mutations were located upstream from the region corresponding to the human APC mutation cluster region. Dietary folate had no effect on the frequency and type of Apc mutations. No mutations were detected in exons 5-9 of the p53 gene in neoplastic lesions. These data suggest that in the dimethylhydrazine rat model of colorectal cancer, the Apc gene is mutated in early stages, albeit to a lesser degree than observed in human colorectal cancer, whereas the mutational hot spot of the p53 gene for human colorectal cancer is not commonly mutated. Although the low frequency of Apc mutations and the small number of neoplasms studied in this study might have precluded our ability to observe modulatory effects of folate, dietary folate appears to have no significant effect on Apc and p53 mutations.

Chronic alcohol consumption induces genomic but not p53-specific DNA hypomethylation in rat colon

Alcohol consumption has been implicated as an etiologic agent in colorectal carcinogenesis, but the mechanism by which alcohol enhances the development of colorectal cancer is not yet known. Recent reports indicate that alcohol consumption can diminish cellular S-adenosylmethionine levels, thus possibly altering normal patterns of DNA methylation, a phenomenon that is mediated by S-adenosylmethionine and whose abnormalities are observed in colonic neoplasia. This study investigated the effect of chronic alcohol consumption on genomic DNA methylation of rat colonic epithelium and methylation of the p53 tumor suppressor gene, abnormalities of which have been implicated in colonic carcinogenesis. Two groups of rats (n = 10/group) were pair-fed either an alcohol-containing or an isocaloric control Lieber-DeCarli diet for 4 wk. The extent of genomic DNA methylation was assessed by incubating the extracted DNA with [(3)H]S-adenosylmethionine and Sss1 methyltransferase. Gene-specific methylation was assessed by using semiquantitative polymerase chain reaction (PCR). Tritiated methyl uptake by colonic DNA (which is inversely correlated with genomic methylation) from alcohol-fed rats was 57% less than that in control DNA (P < 0.05). However, gene-specific DNA methylation, both in the p53 gene (exons 5-8) and in the beta-actin gene, a control gene, did not differ between the two groups. In conclusion, this study indicates that chronic alcohol consumption produces genomic DNA hypomethylation in the colonic mucosa. This may constitute a means by which carcinogenesis is enhanced, although further studies are required to establish causality.

Nutritional strategies in the prevention of colorectal cancer

A variety of dietary factors have been implicated as agents that can modulate the development of malignancies of the gastrointestinal tract, particularly colorectal cancer. The effects of fat, red meat, fruits, vegetables, and alcohol on colorectal carcinogenesis have been examined extensively and appear to play substantial roles. Although fiber may play a protective role, recent studies raise the question of whether the protection is conveyed by other components in fiber-laden foods. Folate, selenium, calcium, and omega-3 fatty acids have emerged as factors more recently but may be equally important agents in nutritional chemoprevention, whereas the role of antioxidant vitamins is less certain. Until more firm data are available, the dietary recommendations provided by the American Cancer Society and the National Cancer Institute are appropriate for use in counseling patients on this issue.

Protein-calorie malnutrition does not predict subtle vitamin K depletion in hospitalized patients

OBJECTIVE

Recent studies suggest that subtle vitamin K depletion has far-reaching consequences. As this entity is not associated with prothrombin time elevation, it is important to determine whether alternate methods can help identify it. We investigated subtle vitamin K depletion in a hospital setting and determined whether protein calorie malnutrition predicts its presence.

DESIGN, SETTING, SUBJECTS

Using a high-pressure liquid chromatography (HPLC) assay of plasma phylloquinone and a food frequency questionnaire for phylloquinone intake, we examined the phylloquinone status of 27 hospitalized patients with normal coagulation parameters, no liver disease, and no recent warfarin use. We assessed protein-calorie nutritional status with Reilly's criteria and anthropometrics.

RESULTS

51% of patients (95% CI = 31% to 70%) had evidence of subtle vitamin K depletion as defined by a subnormal plasma phylloquinone concentration. Patients whose phylloquinone intake was less than the Recommended Daily Allowance (RDA) over the preceding year had lower plasma phylloquinone concentrations when compared to other patients: median (range) 0.106 nmol/l (0.022-0.461) versus 0.301 nmol/l (0.067-3.928), respectively (P = 0.023). Plasma phylloquinone concentrations were no different, however, between well-nourished and malnourished patients: median (range) 0.245 nmol/l (0.022-0.522) versus 0.188 nmol/l (0.067-3.928), respectively (P=0.782).

CONCLUSIONS

Subtle vitamin K depletion is common among hospitalized patients and protein-calorie malnutrition does not predict its presence.

Colonic mucosal concentrations of folate correlate well with blood measurements of folate status in persons with colorectal polyps

BACKGROUND

Estimates of habitual dietary folate intake are known to be imprecisely correlated with systemic measures of folate status. Furthermore, measurements of blood folate concentrations may not accurately reflect the concentration of folate in tissues of interest. This issue is important for assessing folate status in the colorectal mucosa because low dietary intake or blood concentrations of folate are associated with an increased risk of colorectal neoplasia.

OBJECTIVE

We examined whether conventional measures of folate in blood and a more sensitive, inverse indicator of systemic folate status, serum homocysteine, accurately reflected folate concentrations in human colonic mucosa obtained by endoscopic biopsy.

DESIGN

In 30 persons with colorectal polyps, blood samples were taken and biopsies of normal rectosigmoid mucosa performed at the time of colonoscopic polypectomy. Serum, red blood cell, and colonic mucosal folate and serum homocysteine concentrations were measured.

RESULTS

Serum and red blood cell folate and serum homocysteine concentrations accurately reflected colonic mucosal folate concentrations; among these, serum homocysteine correlated best with mucosal concentrations. Folate concentrations in the normal rectosigmoid mucosa were significantly lower in persons with adenomatous polyps than in those with hyperplastic polyps (P=0.04). Conventional measures of systemic folate status were not significantly lower in those with adenomas, although serum homocysteine was mildly elevated (P=0.04).

CONCLUSIONS

Our data underscore the ability of systemic measures of folate status, particularly serum homocysteine, to reflect folate concentrations in the colonic mucosa. Nevertheless, future studies that examine the ability of folate to modulate colorectal carcinogenesis may benefit from direct measurement of folate in the colon.

A cross-sectional study of vitamin intake in postoperative non-small cell lung cancer patients

BACKGROUND AND OBJECTIVES

This cross-sectional study of postoperative non-small cell lung cancer (NSCLC) patients examined possible effects of vitamin intake and folate status on disease-free survival.

METHODS

Supplemental vitamin usage, dietary vitamin intake (Willett Food Frequency Questionnaire), red blood cell (RBC) folate, and serum folate concentrations were assessed in patients with a history of NSCLC. Exclusion criteria included factors that alter folate status or that are associated with altered nutritional habits: (1) evidence of cancer on history, physical, or chest radiograph; (2) tobacco, alcohol ingestion (>2 drinks/ day), or cancer treatment within 3 months; (3) use of folate antagonists; and (4) age <60 years.

RESULTS

36 subjects were evaluated. The median disease-free censored survival was 24 months (range 4-41). Nineteen of 36 patients (53%) reported vitamin supplementation. Vitamin users had a longer median censored survival compared with nonusers (41 months versus 11 months; P = 0.002). With adjustment for cancer stage, the association between RBC folate and censored survival (r = 0.35; P = 0.055) and between serum folate and censored survival (r = 0.32; P = 0.083) approached statistical significance.

CONCLUSIONS

NSCLC patients who took vitamin supplements were more likely to be long-term survivors in the patients studied; a similar trend toward long-term survival was seen among patients with higher circulating folate concentrations.

Folate depletion impairs DNA excision repair in the colon of the rat

BACKGROUND/AIMS

Diminished folate status appears to promote colonic carcinogenesis by, as of yet, undefined mechanisms. Impaired DNA repair plays a significant role in the evolution of many colon cancers. Since folate is essential for the de novo synthesis of nucleotides and since folate depletion has previously been associated with excessive DNA strand breaks, it was hypothesised that folate depletion may impair DNA repair. Studies were therefore performed to examine whether folate depletion affects the two major categories of DNA repair.

METHODS

Study 1: eight weanling male Sprague-Dawley rats were fed on diets containing either 0 or 8 mg folate/kg diet with 1% succinylsulphathiazole for four weeks. After viable colonocytes had been harvested, DNA excision repair was evaluated by a single cell gel electrophoresis assay. Study 2: eighteen animals were fed on similar diets for five weeks. Also in study 2, 18 additional rats were fed on the same defined diet without succinylsulphathiazole for 15 weeks. Weekly injections with the procarcinogen, 1,2-dimethylhydrazine (20 mg base/kg), were administered to the latter group of animals. Five microsatellite loci from different chromosomes were investigated for instability in hepatic and colonic DNA.

RESULTS

In study 1, a significantly retarded rate of DNA excision repair was observed in the folate deficient colonocytes compared with controls (p < 0.05). In study 2, there was no evidence of instability at the five microsatellite loci associated with either short or long term folate depletion.

CONCLUSIONS

Folate deficiency impairs DNA excision repair in rat colonic mucosa; a similar degree of deficiency, even when administered in conjunction with a colonic carcinogen, did not produce evidence of a widespread defect in mismatch repair.

Bioavailability of phylloquinone from an intravenous lipid emulsion

This randomized, controlled study evaluated the bioavailability of phylloquinone from an intravenous lipid emulsion. A mild vitamin K deficiency was induced in 12 healthy adult men and women by dietary restriction of phylloquinone (40 microg/d, days 1-11) and by administration of warfarin (1.0 mg/d, days 5-11). On day 11, subjects received a 500-mL intravenous solution of either lipid or saline, both of which contained 154 microg phylloquinone. Bioavailability was assessed by serial measurements of plasma phylloquinone, vitamin K1-2,3-epoxide. PIVKA-II (proteins induced by vitamin K absence or antagonists-II), and percentage undercarboxylated osteocalcin. As a result of vitamin K deficiency and minidose warfarin, vitamin K1-2,3-epoxide, PIVKA-II, and percentage undercarboxylated osteocalcin increased significantly between days 1 and 11 (P = 0.05, 0.016, and 0.001, respectively). With the infusions, plasma phylloquinone increased in both groups (P = 0.001). After the infusions vitamin K,-2,3-epoxide decreased in both groups (P = 0.002). Changes in plasma phylloquinone and vitamin K1-2,3-epoxide were no different in the two groups (mean areas under the curves +/- SEM: 116+/-13 nmol x h/L for the saline group and 102+/-20 nmol x h/L for the lipid group for phylloquinone; 38.6+/-7.5 nmol x h/L for the saline group and 31.3+/-9.0 nmol x h/L for the lipid group for vitamin K1-2,3-epoxide). PIVKA-II decreased significantly from baseline values (P = 0.005) in both groups after the infusions. Intravenous lipid reversed the effects of minidose warfarin and of dietary restriction of phylloquinone on hemostasis and vitamin K nutritional status. This reversal was no different from that seen with the infusion of phylloquinone in a saline solution.

A prospective survey for central line skin-site colonization by the pathogen Malassezia furfur among hospitalized adults receiving total parenteral nutrition

BACKGROUND

Over 50 case reports suggest that Malassezia furfur is an emerging systemic pathogen in neonates who receive IV lipid emulsions. Because isolation of this fungus requires special culture techniques, which are not routinely used, the authors of many case reports of M. furfur infections in adults question whether infections caused by this organism are being underdiagnosed in older patients.

METHODS

Catheter insertion site colonization rates in adults receiving total parenteral nutrition (TPN) were prospectively evaluated in 149 hospitalized patients with 928 cultures handled specifically for M. furfur detection. Positive control samples consisted of M. furfur cultures in neonates and in adults, who had not been enrolled in the study, and of a separate positive culture obtained from a skin site inoculated with M. furfur.

RESULTS

M. furfur was not cultured from any of the 928 study samples (95% confidence interval [CI] -0.4% to +0.4%).

CONCLUSIONS

These results suggest that M. furfur is less of a threat to hospitalized adults receiving TPN than has been otherwise postulated. These data do not support the inclusion of special cultures for M. furfur in routine skin-site surveillance programs among hospitalized adults receiving TPN.