The search for novel migraine therapies: experimental models

The identification and development of the potent 5-HT1B/1D agonist, sumatriptan has resulted in new therapeutic opportunities for the treatment of migraine and a number of chemically novel agents with a similar mechanism of action have been identified. Whilst these agents are optimised to enhance the therapeutic effect of sumatriptan, development of mechanistically novel therapies may provide new directions for the care of migraine sufferers. To develop new treatment paradigms, novel chemical entities should be evaluated in animal models which are predictive of therapeutic efficacy e.g.: in animal models where sumatriptan has shown activity, or the pathophysiological processes involved in the disease must be targeted. Therefore, investigation of mechanisms underlying cortical activity and its involvement in the activation of trigeminal vascular pathways may allow better understanding of the disease and result in the identification of new non-triptan-like therapies.

Nerve injury-associated kinase: a sterile 20-like protein kinase up-regulated in dorsal root ganglia in a rat model of neuropathic pain

Partial injury of the rat sciatic nerve elicits a variety of characteristic chemical, electrophysical and anatomical changes in primary sensory neurons and constitutes a physiologically relevant model of neuropathic pain. To elucidate molecular mechanisms that underlie the physiology of neuropathic pain, we have used messenger RNA differential display to identify genes that exhibit increased ipsilateral expression in L4/5 dorsal root ganglia, following unilateral partial ligation of the rat sciatic nerve. One set of partial complementary DNA clones identified in this screen was found to encode a protein kinase, nerve injury-associated kinase. Cloning of the full-length human nerve injury-associated kinase complementary DNA, together with recombinant expression analysis, reveal nerve injury-associated kinase to be a functional member of a subgroup of sterile 20-like protein kinases characterised by the presence of a putative carboxy terminal autoregulatory domain. Induction of nerve injury-associated kinase expression in dorsal root ganglia in the rat neuropathic pain model was confirmed by quantitative reverse transcription-polymerase chain reaction, and RNA in situ hybridization analysis revealed enhanced levels of nerve injury-associated kinase within neurons.Together, our data implicate nerve injury-associated kinase as a novel upstream component of an intracellular signalling cascade that is up-regulated in dorsal root ganglia neurons in response to sciatic nerve injury.

Relation between plasma ascorbic acid and mortality in men and women in EPIC-Norfolk prospective study: a prospective population study. European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Ascorbic acid (vitamin C) might be protective for several chronic diseases. However, findings from prospective studies that relate ascorbic acid to cardiovascular disease or cancer are not consistent. We aimed to assess the relation between plasma ascorbic acid and subsequent mortality due to all causes, cardiovascular disease, ischaemic heart disease, and cancer.

METHODS

We prospectively examined for 4 years the relation between plasma ascorbic acid concentrations and mortality due to all causes, and to cardiovascular disease, ischaemic heart disease, and cancer in 19 496 men and women aged 45-79 years. We recruited individuals by post using age-sex registers of general practices. Participants completed a health and lifestyle questionnaire and were examined at a clinic visit. They were followed-up for causes of death for about 4 years. Individuals were divided into sex-specific quintiles of plasma ascorbic acid. We used the Cox proportional hazard model to determine the effect of ascorbic acid and other risk factors on mortality.

FINDINGS

Plasma ascorbic acid concentration was inversely related to mortality from all-causes, and from cardiovascular disease, and ischaemic heart disease in men and women. Risk of mortality in the top ascorbic acid quintile was about half the risk in the lowest quintile (p<0.0001). The relation with mortality was continuous through the whole distribution of ascorbic acid concentrations. 20 micromol/L rise in plasma ascorbic acid concentration, equivalent to about 50 g per day increase in fruit and vegetable intake, was associated with about a 20% reduction in risk of all-cause mortality (p<0.0001), independent of age, systolic blood pressure, blood cholesterol, cigarette smoking habit, diabetes, and supplement use. Ascorbic acid was inversely related to cancer mortality in men but not women.

INTERPRETATION

Small increases in fruit and vegetable intake of about one serving daily has encouraging prospects for possible prevention of disease.

Empirical evidence of correlated biases in dietary assessment instruments and its implications

Multiple-day food records or 24-hour recalls are currently used as "reference" instruments to calibrate food frequency questionnaires (FFQs) and to adjust findings from nutritional epidemiologic studies for measurement error. The common adjustment is based on the critical requirements that errors in the reference instrument be independent of those in the FFQ and of true intake. When data on urinary nitrogen level, a valid reference biomarker for nitrogen intake, are used, evidence suggests that a dietary report reference instrument does not meet these requirements. In this paper, the authors introduce a new model that includes, for both the FFQ and the dietary report reference instrument, group-specific biases related to true intake and correlated person-specific biases. Data were obtained from a dietary assessment validation study carried out among 160 women at the Dunn Clinical Nutrition Center, Cambridge, United Kingdom, in 1988-1990. Using the biomarker measurements and dietary report measurements from this study, the authors compare the new model with alternative measurement error models proposed in the literature and demonstrate that it provides the best fit to the data. The new model suggests that, for these data, measurement error in the FFQ could lead to a 51% greater attenuation of true nutrient effect and the need for a 2.3 times larger study than would be estimated by the standard approach. The implications of the results for the ability of FFQ-based epidemiologic studies to detect important diet-disease associations are discussed.

Patterns of physical activity and ultrasound attenuation by heel bone among Norfolk cohort of European Prospective Investigation of Cancer (EPIC Norfolk): population based study

OBJECTIVES

To study associations between patterns of physical activity and ultrasound attenuation by the heel bone in men and women.

DESIGN

Cross sectional, population based study.

SETTING

Norfolk.

PARTICIPANTS

2296 men and 2914 women aged 45-74 registered with general practices participating in European Prospective Investigation into Cancer (EPIC Norfolk).

RESULTS

Self reported time spent in high impact physical activity was strongly and positively associated with ultrasound attenuation by the heel bone, independently of age, weight, and other confounding factors. Men who reported participating in >/=2 hours/week of high impact activity had 8.44 dB/MHz (95% confidence interval 4.49 to 12.40) or 9.5%, higher ultrasound attenuation than men who reported no activity of this type. In women, the difference in ultrasound attenuation between those reporting any high impact activity and those reporting none was 2.41 dB/MHz (0.45 to 4.37) or 3.4% higher. In women this effect was similar in size to that of an age difference of four years. Moderate impact activity had no effect. However, climbing stairs was strongly independently associated with ultrasound attenuation in women (0.64 dB/MHz (0.19 to 1.09) for each additional five flights of stairs). There was a significant negative association in women between time spent watching television or video and heel bone ultrasound attenuation, which decreased by 0.08 dB/MHz (0.02 to 0.14) for each additional hour of viewing a week.

CONCLUSIONS

High impact physical activity is independently associated with ultrasound attenuation by the heel bone in men and women. As low ultrasound attenuation has been shown to predict increased risk of hip fracture, interventions to promote participation in high impact activities may help preserve bone density and reduce the risk of fracture. However, in older people such interventions may be inappropriate as they could increase the likelihood of falls.

Glycated haemoglobin, diabetes, and mortality in men in Norfolk cohort of european prospective investigation of cancer and nutrition (EPIC-Norfolk)

OBJECTIVE

To examine the value of glycated haemoglobin (HbA(1c)) concentration, a marker of blood glucose concentration, as a predictor of death from cardiovascular and all causes in men.

DESIGN

Prospective population study.

SETTING

Norfolk cohort of European Prospective Investigation into Cancer and Nutrition (EPIC-Norfolk).

SUBJECTS

4662 men aged 45-79 years who had had glycated haemoglobin measured at the baseline survey in 1995-7 who were followed up to December 1999.

MAIN OUTCOME MEASURES

Mortality from all causes, cardiovascular disease, ischaemic heart disease, and other causes.

RESULTS

Men with known diabetes had increased mortality from all causes, cardiovascular disease, and ischaemic disease (relative risks 2.2, 3.3, and 4.2, respectively, P <0.001 independent of age and other risk factors) compared with men without known diabetes. The increased risk of death among men with diabetes was largely explained by HbA(1c) concentration. HbA(1c) was continuously related to subsequent all cause, cardiovascular, and ischaemic heart disease mortality through the whole population distribution, with lowest rates in those with HbA(1c) concentrations below 5%. An increase of 1% in HbA(1c) was associated with a 28% (P<0.002) increase in risk of death independent of age, blood pressure, serum cholesterol, body mass index, and cigarette smoking habit; this effect remained (relative risk 1.46, P=0.05 adjusted for age and risk factors) after men with known diabetes, a HbA(1c) concentration >/=7%, or history of myocardial infarction or stroke were excluded. 18% of the population excess mortality risk associated with a HbA(1c) concentration >/=5% occurred in men with diabetes, but 82% occurred in men with concentrations of 5%-6.9% (the majority of the population).

CONCLUSIONS

Glycated haemoglobin concentration seems to explain most of the excess mortality risk of diabetes in men and to be a continuous risk factor through the whole population distribution. Preventive efforts need to consider not just those with established diabetes but whether it is possible to reduce the population distribution of HbA(1c) through behavioural means.

Dose-dependent effect of dietary meat on endogenous colonic N-nitrosation

Human male volunteers were studied in a metabolic facility whilst they were fed randomized controlled diets. In eight volunteers there was a significant increase in faecal apparent total N:-nitroso compounds (ATNC) and nitrite excretion (P < 0.0001 and P = 0.046, respectively) when randomized doses of meat were increased from 0 to 60, 240 and 420 g/day over 10 day periods. Mean (+/- SE) faecal ATNC levels were 54 +/- 7 microg/day when the diets contained no meat, 52 +/- 11 microg/day when the diets contained 60 g meat/day, 159 +/- 33 microg/day with 240 g meat and 199 +/- 36 microg/day with 420 g meat. Higher concentrations of NOC were associated with longer times of transit in the gut (r = 0.55, P = 0.001) and low faecal weight (r = -0.51, P = 0.004). There was no significant decline in levels in individuals fed 420 g meat for 40 days. The exposures found on the higher meat diets were comparable with other sources of N:-nitroso compounds (NOC), such as tobacco smoke. Many NOC are known large bowel initiators and promotors in colon cancer, inducing G-->A transitions in codons 12 and 13 of K-ras. Endogenous NOC formation, combined with prolonged transit times in the gut, may explain the epidemiological associations between high meat/low fibre diets and colorectal cancer risk.

Inhibition of inflammation-induced thermal hypersensitivity by sumatriptan through activation of 5-HT(1B/1D) receptors

Migraine is effectively treated by drugs acting via 5-HT(1B/1D) receptors; however, the antinociceptive effects of such agents have not been fully investigated, particularly in models in which sensitization may be present. The aim of these studies was to evaluate the effects of the 5-HT(1B/1D) receptor agonist sumatriptan in specific models of pain states: a mouse model of inflammation-induced thermal hyperalgesia and a rat model of nerve injury-induced thermal hyperalgesia. In female mice, following intraplantar injection of carrageenan 225 min earlier, sumatriptan (300 microg/kg intraperitoneally; i.p.) increased paw withdrawal latency (PWL) from 3.1 +/- 0.4 s in the saline group to 5.6 +/- 0.9 s, measured 240 min postcarrageenan (P < 0.05 ANOVA followed by post hoc Dunnett's test). A similar effect was seen in male mice. Sumatriptan was also effective in male mice when given i.p. and subcutaneously 15 min precarrageenan, with a maximum effect at 30 microg/kg (i.p. latency 7.4 +/- 1.3 s compared to saline group, 2.6 +/- 0.7 s; i.v. latency 5.9 +/- 0.8 s compared to saline group, 2.9 +/- 0.3 s; P < 0.05 ANOVA followed by post hoc Dunnett's test). The number of mice required to give a response that could be reliably attributed to sumatriptan (number needed to treat) was calculated using discriminant analysis and found to be 2.6. The ability of sumatriptan to attenuate the carrageenan-induced reduction in PWL was blocked by the mixed 5-HT(1B/1D) receptor antagonist GR-127935 (3 mg/kg i.p.) but not by the 5-HT(1B) receptor antagonist SB-224289 (10 mg/kg i.p.). Sumatriptan had no effect on thermal hyperalgesia induced by sciatic nerve ligation in the rat at any time point. These data demonstrate that sumatriptan attenuates the hypersensitivity to noxious thermal stimuli induced by intraplantar carrageenan.

Carrageenan-induced thermal hyperalgesia in the mouse: role of nerve growth factor and the mitogen-activated protein kinase pathway

NGF is an important link between inflammation and hyperalgesia and interacts with many different mediators of inflammation, including the MAPK signaling pathway. In these studies, carrageenan-induced thermal hyperalgesia was evaluated in the mouse and the role of NGF and the MAPK pathway investigated. Carrageenan induced a time-dependent inflammation and thermal hyperalgesia, which was maximal 4 h post administration. Both indomethacin (0.3, 1.0 and 10 mg/kg s.c., 30 min pre-carrageenan) and morphine (0.4, 1.2, 4.0 mg/kg; s.c., 30 min pre-hyperalgesia measurement) significantly inhibited carrageenan-induced thermal hyperalgesia and indomethicin inhibited paw inflammation, demonstrating the model as suitable for the assessment of anti-hyperalgesic and anti-inflammatory agents. Anti-NGF (0.67 mg/kg sc, 60 min pre-carrageenan) produced a significant inhibition of thermal hyperalgesia, but not inflammation. NGF itself produced a time-dependent hyperalgesia, but not inflammation, following intraplantar injection. The specific MAPK pathway inhibitor, PD98059 (0.1, 0.3 and 1 mg/kg sc, 30 min pre-carrageenan) significantly inhibited carrageenan-induced hyperalgesia, but not inflammation. These data demonstrate a role for both NGF and the MAPK signaling pathway in the production of thermal hyperalgesia, but not inflammation, in the mouse.

Protein degradation in the large intestine: relevance to colorectal cancer

Colorectal cancer is the second most common form of cancer death in Western countries. Diet has been implicated in the aetiology of this disease. Epidemiological evidence suggests that diets high in meat and fat and low in fermentable carbohydrate increase colorectal cancer risk. One mechanism that could explain the association with meat is increased colonic protein metabolism due to increased protein intake from high meat diets. Products of colonic protein degradation and metabolism include ammonia, phenols, indoles and amines which have been shown to exert toxic effects in vitro and in animal models. These compounds are present in faecal samples suggesting that they may exert gut mucosal effects. Human studies have shown that colonic protein metabolism via the gut microflora is responsive to dietary protein as faecal ammonia and urinary phenolic compound concentrations increase in response to increased intake of protein rich foods. Other toxic metabolites from dietary protein precursors such as N-nitroso compounds and sulphides are also formed. Recent work has shown that diets high in meat, fat and low in fibre increase human faecal water genotoxicity. It is likely that metabolites from colonic protein metabolism contribute to this increase in genotoxicity during high meat intakes.

Department of Veterans Affairs Cooperative Studies Program genetic linkage study of schizophrenia: ascertainment methods and sample description

To help clarify the genetics of schizophrenia, the Department of Veterans Affairs Cooperative Studies Program has completed data collection for a genetic linkage study of schizophrenia. This article describes the methodological details of the data collection. Subsequent articles will describe the results of our genome scan, which is now in progress. The data collection protocol included the Diagnostic Interview for Genetic Studies, the Family Interview for Genetic Studies, a review of medical records, and the collection of blood for transformation into lymphoblast cell lines. Among relatives of schizophrenic probands, we assessed auditory attention and verbal memory with neuropsychological tests. Among the 166 families ascertained for the study, 143 had a single affected sib-pair, 17 had three affected siblings, one had five affected siblings and five had two sets of affected siblings. There was a total of 216 affected sib-pairs in these families. Using the n-1 rule, these families contain 188 independent affected sib-pairs.

Vitamin C and hyperglycemia in the European Prospective Investigation into Cancer--Norfolk (EPIC-Norfolk) study: a population-based study

OBJECTIVE

To examine the cross-sectional association between plasma vitamin C, self-reported diabetes, and HbA1c.

RESEARCH DESIGN AND METHODS

Data from a population-based study of diet, cancer, and chronic disease were analyzed. A total of 2,898 men and 3,560 women 45-74 years of age who were registered with general practices in Norfolk, U.K., were recruited to the European Prospective Investigation Into Cancer-Norfolk study between 1995 and 1998.

RESULTS

Mean plasma vitamin C levels were significantly higher in individuals with HbA1c levels < 7% than in those with self-reported diabetes or prevalent undiagnosed hyperglycemia (HbA1c > or = 7%). An inverse gradient of mean plasma vitamin C was found in both sexes across quintiles of HbA1c distribution < 7%. The odds ratio (95% CI) of having prevalent undiagnosed hyperglycemia per 20 micromol/l (or 1 SD) increase in plasma vitamin C was 0.70 (0.52-0.95) (adjusted for sex, age, BMI, waist-to-hip ratio, tertiary education, any use of dietary supplements, vegetarian diet, alcohol consumption, physical activity, dietary vitamin E, dietary fiber, dietary saturated fat, and smoking history). The unadjusted change in HbA1c per 20 micromol/l increase in vitamin C estimated by linear regression was -0.12% (-0.14 to -0.09) in men and -0.09% (-0.11 to -0.07) in women. After adjusting for the possible confounders, these values were -0.08% (-0.11 to -0.04) in men and -0.05% (-0.07 to -0.03) in women.

CONCLUSIONS

An inverse association was found between plasma vitamin C and HbA1c. Dietary measures to increase plasma vitamin C may be an important public health strategy for reducing the prevalence of diabetes.

Vanilloid receptor-1 is essential for inflammatory thermal hyperalgesia

The vanilloid receptor-1 (VR1) is a ligand-gated, non-selective cation channel expressed predominantly by sensory neurons. VR1 responds to noxious stimuli including capsaicin, the pungent component of chilli peppers, heat and extracellular acidification, and it is able to integrate simultaneous exposure to these stimuli. These findings and research linking capsaicin with nociceptive behaviours (that is, responses to painful stimuli in animals have led to VR1 being considered as important for pain sensation. Here we have disrupted the mouse VR1 gene using standard gene targeting techniques. Small diameter dorsal root ganglion neurons isolated from VR1-null mice lacked many of the capsaicin-, acid- and heat-gated responses that have been previously well characterized in small diameter dorsal root ganglion neurons from various species. Furthermore, although the VR1-null mice appeared normal in a wide range of behavioural tests, including responses to acute noxious thermal stimuli, their ability to develop carrageenan-induced thermal hyperalgesia was completely absent. We conclude that VR1 is required for inflammatory sensitization to noxious thermal stimuli but also that alternative mechanisms are sufficient for normal sensation of noxious heat.

Identification of differentially expressed genes in dorsal root ganglia following partial sciatic nerve injury

Partial sciatic nerve injury, a model of neuropathic pain, elicits a variety of neurochemical, electrophysiological and neuroanatomical changes in primary sensory neurons. We have used the technique of messenger RNA differential display to identify genes with altered expression in these neurons which may contribute to the development of aberrant sensation following such peripheral nerve damage. This approach identified 14 distinct complementary DNA clones, representing transcripts with increased ipsilateral expression in L4/5 dorsal root ganglia, two weeks after unilateral partial ligation of the rat sciatic nerve. Both Zucker diabetic fatty rats and their lean counterparts were used in this study but none of the transcripts identified showed an induction that was confined to one of the two groups. The majority of the clones did not show significant sequence similarity to previously reported genes and therefore may represent novel messenger RNA sequences or, alternatively, unknown regions of partially characterised messenger RNAs. Two of the clones represented transcripts for the known proteins muscle LIM protein and acidic epididymal glycoprotein, neither of which had previously been associated with expression in the nervous system. Reverse transcriptase-polymerase chain reaction analysis and in situ hybridization confirmed that the messenger RNA expression of both muscle LIM protein and acidic epididymal glycoprotein was induced in an ipsilateral-specific manner. Their localisations, examined with in situ hybridization in L5 dorsal root ganglia, were limited in each case to a sub-population of neuronal profiles. Those neuronal profiles that demonstrated muscle LIM protein hybridization were distributed across the profile size range, whereas the distribution of acidic epididymal glycoprotein-positive profiles appeared to be skewed towards smaller profiles. The induction of muscle LIM protein and acidic epididymal glycoprotein in dorsal root ganglia may play an important functional role in the adaptive response of primary sensory neurons following partial sciatic nerve injury.

A method to compensate for incomplete 24-hour urine collections in nutritional epidemiology studies

OBJECTIVE

To develop a method to make use of incomplete 24-hour urinary samples in nutritional epidemiology, especially when validating the dietary intake of nitrogen (protein), sodium and potassium.

DESIGN

Urinary data for men and women collected in three different studies were evaluated. The concentration of para-aminobenzoic acid (PABA) in one 24-hour urine sample per person was compared with the concentrations of nitrogen, sodium, potassium and creatinine.

SETTING

Men and women living in Cambridge, UK and women living in the town of Varberg, Sweden.

SUBJECTS

In total, this study consists of data from 73 Swedish women (20-50 years of age), 165 UK women (50-65 years) and 75 UK men (55-88 years).

RESULTS

On average four out of 10 people in this study had a PABA recovery below 85%. The linear regression equations for urinary excretion of nitrogen, sodium and potassium in relation to PABA recovery were y=2.3 + 0.088 x chi (r=0.99), y=45 + 0.82 x chi (r= 0.87) and y = 19 + 0.60 x chi (r= 0.93), respectively.

CONCLUSIONS

The linear regression equations can be used for adjusting urinary nitrogen, sodium and potassium in urinary collections in cases where the PABA recovery is below 85%. Since it is common to obtain 24-hour urine collections with a PABA recovery below 85%, this method should increase the usefulness of biological markers of food intake in nutritional epidemiological studies and also increase the possibilities to study people that previously have been part of the drop-out group or the group with low motivation and cooperation. It is important to stress that we have not studied the relationship between PABA recovery and various urinary variables below the PABA recovery of 50%. Thus, in a case of PABA recovery below 50%, we do not recommend the use of this method to compensate for incomplete collections.

Thermal, but not mechanical, nociceptive behavior is altered in the Zucker Diabetic Fatty rat and is independent of glycemic status

This study investigated the possible link between developing hyperglycemia and mechanical and/or thermal hyperalgesia in the Zucker Diabetic Fatty (ZDF) rat. When normoglycemic (nonfasting blood glucose levels of 6 mM), 6-week-old ZDF rats were glucose intolerant compared to the nondiabetic Zucker lean control (ZL) rats, but there was no difference in their response to a noxious mechanical (paw pressure test) or thermal (hot plate) stimulus (mechanical nociceptive thresholds: ZDF 176.7+/-14.4 g, ZL 161.7+/-13.3 g; latencies to response to the thermal stimulus: ZDF 13.1+/-1.6 sec, ZL 16.7+/-1.5 sec). Blood glucose levels in untreated ZDF rats increased to 28.4+/-2.9 mM by 20 weeks of age, while ZDF rats treated with the insulin sensitizer, rosiglitazone, and ZL rats remained normoglycemic (< or =8 mM) throughout the study. Hyperglycaemia in ZDF rats was not associated with mechanical hyperalgesia, as the nociceptive threshold remained constant in both the rosiglitazone-treated and untreated ZDF rats and in the ZL rats throughout the study. In contrast, the latency to response to the thermal stimulus increased with time in ZL rats, but remained constant in hyperglycaemic ZDF rats such that the difference reached significance by 9 weeks of age (ZDF 11.6+/-1.7 sec, ZL 21.8+/-2.7 sec, p<0.01) and is consistent with hyperalgesia in the ZDF phenotype. However, this difference was not moderated by maintaining normoglycaemia in rosiglitazone-treated ZDF rats (12.8+/-1.3 sec). Together, the data suggest that hyperglycemia does not play a central role in the development of hyperalgesia in the ZDF rat.

Plasma vitamin C: what does it measure?

OBJECTIVE

To examine the association between self-reported consumption of foods and plasma vitamin C levels.

DESIGN

A cross-sectional analysis of dietary data and plasma vitamin C levels. Subjects placed the following foods into frequency categories: fresh fruit, leafy greens, other vegetables, fatty fish, other fish, chicken, meat, meat products, eggs, cheese and brown bread. The six frequency categories ranged from 'never' to 'at least daily'. Plasma vitamin C was measured by fluorometric assay.

SETTING

A population-based cohort study in Norfolk, UK.

SUBJECTS

598 men and 566 women aged 45-74 years not taking vitamin supplements.

RESULTS

Plasma vitamin C was positively correlated with intake of fresh fruit (r=0.29 in men and r=0.25 in women, P<0.001), leafy greens (r=0.20 in men P<0.001, r=0.13 in women P<0.01), other vegetables (r=0.20 in men P<0.001, r=0.14 in women P<0.01) and brown bread (r=0.28 in men, r=0.17 in women, P<0.001) and negatively associated with intake of meat products (r=-0.13 in men P=0.02, r=-0.10 in women P<0.01). The difference in plasma vitamin C between never and daily eaters of brown bread was 13.6 micronol l(-1) in men and 9.9 micromol l(-1) in women, P<0.001.

CONCLUSIONS

These data suggest that plasma vitamin C is not only a marker of foods rich in vitamin C but of certain patterns of food consumption. Such patterns are likely to be population specific and might explain inconsistencies in biomarker-disease associations.

The effects of season and alcohol intake on mineral metabolism in men

We have examined the relationship between self-reported alcohol intake (SRAI), season and mineral metabolism in a series of 96 men aged 32 to 78 years of age. Alcohol intake was reported as between 0 and 50 oz/week. SRAI correlated positively with liver function tests, including serum bilirubin, alkaline phosphatase, and AST initially and at 6 months. In addition, SRAI correlated with serum calcium, testosterone, estradiol, and immunoreactive parathyroid hormone (iPTH) as well as urinary calcium [per 100 mg of creatinine (Cr)], and pyridinoline crosslinks (DPC) (per 100 mg of Cr). We have divided the participants into two groups on the basis of their reported alcohol intake. Individuals with none-to-moderate intake had <8.4 oz/week of ethanol. Those with moderate or heavier intake had 8.4 oz or more of ethanol/week. Individuals with none-to-moderate SRAI had a significant seasonal increase in iPTH, osteocalcin, urine DPC/100 mg of Cr and a decrease in distal forearm bone mineral density, 25 hydroxyvitamin D (250HD), and urinary calcium/100 mg of Cr. Individuals with moderate or heavier SRAI only had significant seasonal decrease in 250HD. We have concluded that alcohol intake decreases seasonal change in serum iPTH. The biological effects of such alterations in parathyroid hormone levels include decreased seasonal loss of bone mineral density.

Sewing-pin perforation of the appendix into the bladder

We report a 2.5-year-old child who presented with an acute abdomen caused by the perforation of a sewing pin through her appendix that had started to penetrate the wall of the bladder.