The association between migraine and dementia - a national register-based matched cohort study

OBJECTIVES

Migraine and dementia, two major public health challenges, are associated, but more knowledge is needed to understand their relationship. Objectives of this study were to investigate 1) the association between non-self-reported measures of migraine and dementia, and whether dementia was associated with 2) migraine without aura (MO) and with aura (MA) in combination with migraine medication use, and 3) migraine severity operationalized as the number of migraine prescriptions.

STUDY DESIGN

Matched cohort study.

METHODS

National register data were obtained from individuals born between 1934 and 1958. Migraine cases (aged 25-58 years) were identified by migraine diagnoses and redeemed migraine medication. Migraine cases were matched with non-cases (N = 340,850) and date of diagnosis or medication redemption was defined as index year. Dementia was identified by dementia diagnoses and redeemed dementia medication.

RESULTS

We observed a 1.46 (95% CI: 1.26-1.69) times higher dementia rate in individuals with a migraine diagnosis and a 0.86 (95% CI: 0.76-0.97) times lower rate when using migraine medication. We found the highest dementia rate among individuals with MA, who also used migraine medication (HR = 2.23; 95% CI: 1.19-4.17), and the lowest rate among individuals with MO, who also used medication (HR = 1.25; 95% CI: 0.75-2.10). The number of migraine medication prescriptions was not associated with dementia.

CONCLUSIONS

Being registered with a migraine diagnosis was associated with a higher dementia rate, while use of prescribed migraine medication was not. The differences in the dementia rate among migraine cases identified via diagnoses versus medications warrants further investigation.

Prescribing of proton-pump inhibitors: auditing the management and reasons for prescribing in Danish general practice

BACKGROUND

Prescribing of proton-pump inhibitors has substantially increased. Information from clinical settings is warranted to gain insight into reasons for prescribing.

AIM

To investigate Danish General Practitioners' management and reasons for prescribing of proton-pump inhibitors and to identify areas for quality improvement.

METHODS

All general practitioners in the Region of Southern Denmark and their staff were invited to participate in a 4-week audit on all contacts with patients prescribed proton-pump inhibitors. For each contact, patient characteristics, treatment duration, dose and causes of treatment, previous gastroscopy, Helicobacter pylori test, and decision about future treatment were recorded.

RESULTS

A total of 51 general practitioners and 47 staff members sampled information about 1101 and 741 patients, respectively. Proton-pump inhibitors had been taken for more than 2 years in 58% of the cases, and 64% of the patients used it daily. Treatment was based on an appropriate reason in three of the four patients, most often due to acid-related symptoms. No gastroscopy had been performed in 46% of the patients, and one of four had had a consultation with the general practitioner regarding proton-pump inhibitor within the last year.

CONCLUSION

Most patients treated with proton-pump inhibitors are treated daily, on a long-term basis, and due to symptoms. Few consultations led to alterations in treatment, and only 25% of patients had a consultation regarding proton-pump inhibitor treatment with their general practitioner within the last year. Substantial variability between general practitioners with regard to management was detected.

More precise phenotyping of cluster headache using prospective attack reports

BACKGROUND AND PURPOSE

The clinical characteristics of cluster headache (CH) are based mainly on retrospective attack descriptions of 'usual' attacks, but whether these reports are reliable is uncertain. The aim was to compare retrospective and prospective attack descriptions and describe the within- and between-patient variability of attacks.

METHOD

Fifty-seven CH patients underwent a semi-structured interview obtaining a retrospective account of usual CH attacks. Patients thereafter prospectively recorded the clinical characteristics of up to 10 attacks per patient in a headache diary. Four different attack characteristics were investigated: (i) severity, (ii) duration, (iii) number of autonomic symptoms and (iv) number of migrainous symptoms. Retrospective and prospective data were compared. Within- and between-patient variability of attacks was assessed.

RESULTS

Retrospective attack descriptions (n = 57) were significantly longer (P = 0.046) and more severe (P < 0.0001) for untreated attacks compared with prospective reports (n = 500). The number of autonomic symptoms was significantly higher in the retrospective reports compared to the prospective reports (P < 0.0001). Within-patient variability for attack duration, pain severity and number of autonomic and migrainous symptoms was low. Compared to men, more women reported longer (P = 0.026) and more severe (P = 0.028) attacks with more migrainous symptoms (P = 0.033).

CONCLUSIONS

Important differences were found between prospectively and retrospectively reported attacks with duration and severity of untreated attacks overestimated in retrospective attack descriptions. CH attacks display low within-patient variability, but the presentation of CH attacks varies between patients. The high prevalence of symptoms typically associated with migraine should raise more diagnostic awareness for CH, especially in women who are more often misdiagnosed as having migraine.

Donor Kidney With Renal Cell Carcinoma Successfully Treated With Radiofrequency Ablation: A Case Report

BACKGROUND

The risk of donor-transmitted cancer is evident.

CASE REPORT

We report the case of a 69-year-old woman who was transplanted with a kidney from a deceased donor. Four days after transplantation a routine ultrasound scan revealed a 3-cm tumor in the middle-upper pole of the allograft. A biopsy showed the tumor to be papillary renal cell carcinoma. The patient was treated with radiofrequency ablation. This procedure was complicated by the development of a cutaneous fistula and open surgery was done with resection of an area of necrosis in the kidney and of the fistula. The maintenance immunosuppressive regimen was modified with a change in treatment to everolimus in combination with reduced dose mycophenolate and low-dose steroids. The patient was followed for 4.5 years and during that time she remained dialysis independent with an excellent allograft function (serum creatinine, 95 μmol/L [1.04 mg/dL]).

CONCLUSIONS

To the best of our knowledge, this is the first case in which a donor-transmitted tumor was diagnosed in the renal allograft only 4 days after transplantation and subsequently treated successfully with radiofrequency ablation.

Medical and non-medical predictors of initiating long-term use of proton pump inhibitors: a nationwide cohort study of first-time users during a 10-year period

BACKGROUND

Studies of the increasing use of proton pump inhibitors (PPIs) have mainly focused on prevalent long-term use and associations with gastrointestinal morbidity and comedication. Little is known about non-medical characteristics of first-time users of PPI, and predictors of initiating long-term use of PPIs.

AIMS

To describe medical and non-medical characteristics of first-time PPI users during a 10-year period and to analyse predictors of initiation of long-term use (>60 defined daily doses (DDDs) within 6 months) of PPIs.

METHODS

A nationwide cohort study of first-time users of PPI. Data were collected from Danish national registers. Individuals redeeming their first prescription for a PPI (omeprazole, lansoprazole, pantoprazole, rabeprazole, esomeprazole) in 2001 and 2011 were identified. Redemption of more than 60 DDDs of PPI within 6 months defined long-term use. Logistic regression models were used to determine the associations between previous diagnoses, comedication and socio-economic characteristics and initiation of long-term use of PPIs in 2011.

RESULTS

From 2001 to 2011 incidence of first-time users increased with an incidence rate ratio of 1.53 and mean quantity of PPI redeemed at first prescription increased by 44.6%. In 2011 a total of 37.6% redeemed >60 DDDs within 6 months, and 96% of the long-term users did not have a diagnosis registered which indicated treatment. New onset long-term use was significantly associated with low income and low educational level when adjusting for other predisposing variables.

CONCLUSIONS

Proton pump inhibitor treatment is increasingly initiated with larger quantities prescribed for indications that are unidentifiable from the registers. Morbidity and comedication seem to be the strongest predictors of new onset long-term use of PPIs. However, there is also an independent social gradient.

Vasoactive Intestinal Polypeptide Evokes Only a Minimal Headache in Healthy Volunteers

The role of the parasympathetic nervous system in the pathogenesis of migraine is disputed. The headache-eliciting effect of the parasympathetic neurotransmitter, vasoactive intestinal polypeptide (VIP), and its effect on cerebral arteries and brain haemodynamics has not been systematically studied in man. We hypothesized that infusion of VIP might induce headache in healthy subjects and cause changes in cerebral haemodynamics. VIP (8 pmol/kg per min) or placebo (0.9± saline) was infused for 25 min into 12 healthy young volunteers in a crossover, double-blind design. Headache was scored on a verbal rating scale from 0 to 10, regional cerebral blood flow (rCBF) was measured with single-photon emission computed tomography and 133Xe inhalation and mean flow velocity in the middle cerebral artery (VmeanMCA) was measured with transcranial Doppler ultrasonography. The headache was very mild with a maximum score of 2 and described as a pressing or throbbing sensation. Five participants developed headache during VIP and one during placebo. During the infusion, a significant drop in VmeanMCA was seen for VIP compared with placebo ( P < 0.001), but the effect quickly waned and no difference was found when comparing the time between 30 and 120 min. In addition, no significant difference in the diameter of the MCA could be found during the infusion. No significant differences in rCBF ( P = 0.10) were found between VIP and placebo. A marked dilation of the superficial temporal artery was seen ( P = 0.04) after VIP in the first 30 min but no difference was found when comparing the time between 30 and 120 min. We found no difference in mean arterial blood pressure between VIP and placebo days but the heart rate increased significantly on a VIP day compared with a placebo day (AUC0–30min, P < 0.001). Plasma VIP was significantly higher on a VIP day compared with placebo (AUC0–80min, P < 0.001). These results show that VIP causes a decrease in VmeanMCA without affecting rCBF. In spite of a marked vasodilator effect in the extracranial vessels and increased plasma VIP, healthy subjects developed only a very mild headache.

General practice variation when initiating long-term prescribing of proton pump inhibitors: a nationwide cohort study

Background

Suggestions of overprescribing of proton pump inhibitors (PPIs) for long-term treatment in primary care have been raised. This study aims to analyse associations between general practice characteristics and initiating long-term treatment with PPIs.

Methods

A nationwide register-based cohort study of patients over 18 years redeeming first-time prescription for PPI issued by a general practitioner in Denmark in 2011. Patients redeeming more than 60 defined daily doses (DDDs) of PPI within six months were defined first-time long-term users. Detailed information on diagnoses, concomitant drug use and sociodemography of the cohort was extracted. Practice characteristics such as age and gender of the general practitioner (GP), number of GPs, number of patients per GP, geographical location and training practice status were linked to each PPI user. Logistic regression analysis was used to determine associations between practice characteristics and initiating long-term prescribing of PPIs.

Results

We identified 90 556 first-time users of PPI. A total of 30 963 (34.2 %) met criteria for long-term use at six months follow-up. GPs over 65 years had significantly higher odds of long-term prescribing (OR 1.32, CI 1.16-1.50), when compared to younger GPs (<45 years). Furthermore, female GPs were significantly less likely to prescribe long-term treatment with PPIs (OR 0.87, CI 0.81-0.93) compared to male GPs.

Conclusions

Practice characteristics such as GP age and gender could explain some of the observed variation in prescribing patterns for PPIs. This variation may indicate a potential for enhancing rational prescribing of PPIs.

High prevalence of ulcer bleeding risk factors in dual antiplatelet-treated patients after percutaneous coronary intervention

INTRODUCTION

Dual antiplatelet therapy is standard treatment following percutaneous coronary intervention (PCI) and stenting. However, such therapy increases the risk of upper gastrointestinal bleeding (UGIB). The risk factors of UGIB are well-documented and proton pump inhibitor (PPI) treatment reduces the risk. The aim was to describe the prevalence of risk factors of UGIB in dual antiplatelet-treated patients.

METHODS

A questionnaire was used to assess the prevalence of risk factors of upper gastrointestinal bleeding among dual antiplatelet-treated first-time PCI patients in Western Denmark. The following characteristics were considered risk factors: increasing age (age 60-69 years and ≥ 70 years); dyspepsia; previous peptic ulcer; use of non-steroidal anti-inflammatory drugs (NSAIDs) (weekly or daily), corticosteroids, selective serotonin reuptake inhibitors (SSRIs) and anticoagulants.

RESULTS

A total of 1,358 patients with a mean age of 64.1 years (range: 33-92 years) were included. The distribution of risk factors was as follows: dyspepsia: 681 patients (50.1%); previous ulcer: 110 (8.1%; 2.3% with bleeding); use of NSAIDs: 214 (15.8%); corticosteroids (2.9%), SSRIs (5.8%) and anticoagulants (6.3%). Defined high-risk patients: 886 (65.2%). PPI treatment prior to PCI was found in 248 (18.3%), of whom 86% were at high risk of UGIB.

CONCLUSION

This study demonstrates a high prevalence of risk factors among PCI patients treated with dual antiplatelet therapy, many of whom were not in PPI treatment.

Prevalence of Chronic Rhinosinusitis in a Population of Patients with Gastroesophageal Reflux Disease

Background

An increased coexistence of gastroesophageal reflux disease (GERD) and chronic rhinosinusitis (CRS) has been reported in epidemiologic and register studies, and reflux has been shown more frequently in patients with CRS in studies using esophagus pH manometry compared to participants without CRS. A discussion is ongoing about whether there might be an association between these two diseases and, if so, whether the association is causal.

Objective

The purpose of this study was to clinically investigate the prevalence and symptom severity scores of CRS among patients with GERD. The results were compared with those of a randomly assigned control group from the general Danish population.

Method

In this case–control study, 82 patients with GERD were examined for CRS using the European Position Paper on Rhinosinusitis and Nasal Polyps criteria, which combine patient history and anterior/posterior rhinoscopy results. Sinonasal-related quality of life was assessed by using the Sino-Nasal Outcome Test 22 (SNOT-22). These results were compared with those of a population-based control group examined for CRS in the same way.

Results

The prevalence of CRS among patients with GERD was 20.7% (95% confidence interval [CI], 12.0%-29.5%), significantly higher than the CRS prevalence of 8.5% (95% CI, 6.8%-10.2%) in the background population. Patients with GERD and CRS had an average SNOT-22 score of 43.8, whereas patients with CRS from the background population scored, on average, 28.1. Having GERD increased the mean SNOT-22 score in patients with CRS by 15.7 (95% CI, 6.5-24.9).

Conclusion

The results of this study provide additional evidence of an association between GERD and CRS and indicate that GERD may play a role in the development of CRS. The results also show that sinonasal-related quality of life is decreased in patients with CRS who also suffer from GERD.

Performance of new thresholds of the Glasgow Blatchford score in managing patients with upper gastrointestinal bleeding

BACKGROUND & AIMS

Upper gastrointestinal hemorrhage (UGIH) is a common cause of hospital admission. The Glasgow Blatchford score (GBS) is an accurate determinant of patients' risk for hospital-based intervention or death. Patients with a GBS of 0 are at low risk for poor outcome and could be managed as outpatients. Some investigators therefore have proposed extending the definition of low-risk patients by using a higher GBS cut-off value, possibly with an age adjustment. We compared 3 thresholds of the GBS and 2 age-adjusted modifications to identify the optimal cut-off value or modification.

METHODS

We performed an observational study of 2305 consecutive patients presenting with UGIH at 4 centers (Scotland, England, Denmark, and New Zealand). The performance of each threshold and modification was evaluated based on sensitivity and specificity analyses, the proportion of low-risk patients identified, and outcomes of patients classified as low risk.

RESULTS

There were differences in age (P = .0001), need for intervention (P < .0001), mortality (P < .015), and GBS (P = .0001) among sites. All systems identified low-risk patients with high levels of sensitivity (>97%). The GBS at cut-off values of ≤1 and ≤2, and both modifications, identified low-risk patients with higher levels of specificity (40%-49%) than the GBS with a cut-off value of 0 (22% specificity; P < .001). The GBS at a cut-off value of ≤2 had the highest specificity, but 3% of patients classified as low-risk patients had adverse outcomes. All GBS cut-off values, and score modifications, had low levels of specificity when tested in New Zealand (2.5%-11%).

CONCLUSIONS

A GBS cut-off value of ≤1 and both GBS modifications identify almost twice as many low-risk patients with UGIH as a GBS at a cut-off value of 0. Implementing a protocol for outpatient management, based on one of these scores, could reduce hospital admissions by 15% to 20%.

Strategies for discontinuation of proton pump inhibitors: a systematic review

PURPOSE

Proton pump inhibitors (PPIs) are considered to be overprescribed. Consensus on how to attempt discontinuation is, however, lacking. We therefore conducted a systematic review of clinical studies on discontinuation of PPIs.

METHODS

Systematic review based on clinical studies investigating discontinuation strategies and discontinuation rates for users of antisecretory medication judged eligible for withdrawal. The databases Medline, Embase and Cochrane Library were searched to December 2013 using the terms antisecretory, anti-ulcer, PPI, acid suppressant, discontinuation, step-down, step down, cessation, tapering, withdrawal and withhold. Search terms were used either singularly or in combination. Papers written in English or Scandinavian were included. Concurrent hand searching was undertaken to pursue references of references. The website ClinicalTrials.gov was searched for unpublished results and ongoing studies. A total of 371 abstracts were scrutinized to determine relevancy.

RESULTS

The thorough search resulted in six clinical studies on strategies for discontinuation of PPIs. All discontinuation regimens used in the studies differed, and several interventions have been tested in order to decrease use of PPIs. Discontinuations were reported across all studies ranging from 14% to 64% without deteriorating symptom control. Tapering seems to be a more effective discontinuation strategy than abrupt discontinuation.

CONCLUSION

Discontinuation of PPIs is feasible in a clinical setting, and a substantial number of the patients treated without a clear indication can safely reduce or discontinue treatment. Tapering seems to be the most effective way of doing this.

Improved renal function after early conversion from a calcineurin inhibitor to everolimus: a randomized trial in kidney transplantation

In an open-label, multicenter trial, de novo kidney transplant recipients at low to medium immunological risk were randomized at week 7 posttransplant to remain on CsA (n = 100, controls) or convert to everolimus (n = 102), both with enteric-coated mycophenolate sodium and corticosteroids. The primary endpoint, change in measured GFR (mGFR) from week 7 to month 12, was significantly greater with everolimus than controls: 4.9 (11.8) mL/min versus 0.0 (12.9) mL/min (p = 0.012; analysis of covariance [ANCOVA]). Per protocol analysis demonstrated a more marked difference: an increase of 8.7 (11.2) mL/min with everolimus versus a decrease of 0.4 (12.0) mL/min in controls (p < 0.001; ANCOVA). There were no differences in graft or patient survival. The 12-month incidence of biopsy-proven acute rejection (BPAR) was 27.5% (n = 28) with everolimus and 11.0% (n = 11) in controls (p = 0.004). All but two episodes of BPAR in each group were mild. Adverse events occurred in 95.1% of everolimus patients and 90.0% controls (p = 0.19), with serious adverse events in 53.9% and 38.0%, respectively (p = 0.025). Discontinuation because of adverse events was more frequent with everolimus (25.5%) than controls (3.0%; p = 0.030). In conclusion, conversion from CsA to everolimus at week 7 after kidney transplantation was associated with a greater improvement in mGFR at month 12 versus CNI-treated controls but discontinuations and BPAR were more frequent.

Identification of New Sources of Resistance in Winter Wheat to Multiple Strains of Xanthomonas translucens pv. undulosa

Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, has re-emerged as an important disease of wheat (Triticum aestivum) in the United States. Planting resistant varieties is the best approach to manage BLS in the absence of effective bactericides. However, most of the wheat varieties currently grown in the Upper Midwest of the United States appeared to be susceptible to BLS. From the core subset of the USDA National Small Grain Collection (NSGC), a set of 605 winter wheat accessions of diverse origin and improvement status were initially inoculated with a virulent strain BLSW16 of X. translucens pv. undulosa from Casselton, ND on the flag leaf of each plant in a greenhouse. Disease reactions were assessed between 7 and 10 days after infiltration using a 0 to 6 rating scale, where ≤2.0 was considered resistant and >2.1 was considered susceptible. Resistance varied with geographic origin and was significantly (P ≤ 0.05) more frequent in accessions from North America compared to accessions from northern, eastern, and southern Europe and from south-central Asia. About 8.3% of accessions tested were resistant, and accessions with an improvement status of "cultivar" were significantly more likely to be resistant than were accessions classified as either landraces or breeding lines. Forty-two of the accessions exhibiting resistance in response to the strain BLSW16 in the first screening test were retested utilizing each of the two additional strains (BLS Cr25 and BLS Lb74 of X. translucens pv. undulosa) collected from Carrington and Lisbon, respectively. Nonparametric data analysis revealed 35 accessions were resistant, one accession, PI 266860, was susceptible to both strains, and six accessions showed differential responses. The majority of the BLS-resistant accessions also were resistant to at least one other important wheat disease based on the Germplasm Resources Information Network (GRIN) data. These results suggest that diverse and novel sources of resistance to BLS identified in this study can be utilized in winter wheat breeding programs.

Actinomyces species: A danish survey on human infections and microbiological characteristics

This study compared phenotypic and genotypic identification of Actinomyces strains, tested susceptibility to antibiotics and evaluated their clinical importance. Thirty-four Actinomyces strains were examined; sixteen type strains, and 18 clinical strains from different hospitals in Denmark from the period 2003-2005. Partial 16S rDNA sequencing using a stretch of 526 bases was used for genotypic identification. Susceptibility testing was done by E-test. The antibiotics examined were: benzylpenicillin, piperacillin with tazobactam, ceftriaxone, meropenem, erythromycin, clindamycin, linezolid, moxifloxacin, tetracycline and tigecycline. Clinical parameters were obtained by reviewing patient records. There was poor agreement between the phenotypic and genotypic identification. Phenotypic tests were helpful in identifying strains closely related by DNA sequences. The strains were sensitive to the examined antibiotics except for moxifloxacin to which most strains were resistant, and a few strains were resistant to meropenem and tetracycline. The clinical strains were from many different types of infections and locations. None of the patients was described as having typical actinomycetic lesions, and an apparently good outcome was obtained with different treatment regimens.

The effect of suppressive therapy of nontoxic diffuse goiter on serum levels of thyroxine, 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine

We studied the effect of suppressive therapy with graded doses of thyroxine (T4) on serum levels of T4, 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine [rT3] in patients with diffuse, nontoxic goiter. For comparison and in order to elucidate the degree of suppression of the pituitary thyroid axis by T3 the effect of suppressive therapy with T3 was studied in the same type of patients. We found that T4 in serum rose significantly to a constant level during T4 treatment (0.10, 0.15 and 0.20 mg/day). Dose-related rises in T4 were only seen after 3 months of treatment. T3 and rT3 only changed minimally. The T4/T3 ratio rose to a constant level during the initial 3 months of treatment. T3/rT3 ratio remained unchanged. No dose-related differences in T4/T3 and T3/rT3 ratio were observed. Treatment with T3 in doses of 0.06 mg per day caused a significant but slow fall in T4 and rT3 to hypothroid levels while T3 only rose slightly. The T4/T3 ratio dropped significantly during T3 therapy.

The effect of different sulfonamides on phenytoin metabolism in man

The influence on the metabolism of phenytoin of some sulfonamides given in common clinical doses has been studied. In single dose experiments sulfaphenazole increased phenytoin half-life (T/2) by 237% and decreased phenytoin metabolic clearance rate (MCR) by 67%. Sulfadiazine, sulfamethiazole, sulfamethoxazole + trimethoprim and trimethoprim increased phenytoin T/2 by 80, 66, 39 and 51% respectively, and decreased phenytoin MCR by 45, 36, 27 and 30% respectively. Sulfamethoxazole gave a small but significant increase in phenytoin T/2 but not a corresponding fall in phenytoin MCR. No changes were found in phenytoin T/2 and MCR after treatment with sulfamethoxypyridazine, sulfadimethoxine and sulfamethoxydiazine. Steady state experiments confirmed the findings of the single dose experiments. It is suggested that sulfaphenazole, sulfadiazine, sulfamethizole, sulfamethoxazole + trimethoprim and trimethoprim inhibit hepatic metabolism of phenytoin.

The effect of repeated intramuscular gonadotrophin-releasing hormone injections on luteinizing hormone, follicle-stimulating hormone, testosterone, oestrogens, dehydroepiandrosterone and dehydroepiandrosterone sulfate in normal men

The endocrine response to three daily intramuscular injections of 500 microgram LH-RH was measured in 9 normal men during a period of 3 days. A marked but declining response in LH was seen in addition to a significant increase in the serum concentration of FSH, testosterone, oestradiol and the urinary excretion of oestrogenic substances. No change could be demonstrated in the DHA, DHAS or cortisol secretion which confirms our previous results of a direct effect of clomiphene on adrenal steroidogenesis.

Kinetics of propylthiouracil in the elderly

The pharmakokinetics of propylthiouracil was evaluated in 9 elderly patients and compared to previous results from 6 younger subjects. By giving the drug both by the intravenous and oral route of administration it was possible to estimate the rate and extent of bioavailability. The various kinetic parameters were calculated according to a two-compartment model by use of two different methods: a graphical hand drawn one and by a special developed computer program based on a least squares minimalisation. While no significant differences could be demonstrated between the two age groups concerning volumes of distribution, clearance and extent of absorption, a large difference was found with regard to the absorption rate constant ka, which was about 3 times higher in the younger than in the elderly subjects, presumably due a reduced gastric emptying time. Considering the comparison between the two methods of calculations all the kinetics parameters were similar except ka and the slow disposition rate constant betw which were underestimated by the graphical method. It is concluded that no-age dependent changes exist concerning the kinetics of propylthiouracil except for a decreased rate of absorption. Graphical methods in pharmacokinetics are useful in obtaining distribution and elimination data but seem often biased for the evaluation of absorption rate constants.

Myxoedema and thyrotoxicosis: relations between clinical state and concentrations of thyroxine and triiodothyronine in blood

The clinical manifestations in thyrotoxic and myxoedematous subjects were assessed by clinical diagnostic score indices and related to the free thyroxine index (FT4I) and the free triiodothyronine index (FT3I), basal metabolic rate (BMR) and in the hypothyroid patients to serum thyrotropin (TSH) level. The clinical score index was significantly correlated to both FT4I and FT3I in both groups of patients. No difference existed in degree of correlation between the clinical score index, on the one hand, and FT3I and FT4I, on the other, in either thyrotoxic or myxoedematous subjects. The degree of correlation between clinical score index and FT3I and FT4I was higher than that between the thyroid hormones and BMR. The clinical score index thus appears to be a better indicator of severity of hyper- and hypothyroidism than BMR. Serum TSH concentration was not correlated to the clinical state.

The preferential role of triiodothyronine in the regulation of basal metabolic rate in hyper- and hypothyroidism

The free triiodothyronine index (FT3I) was significantly correlated to basal metabolic rate (BMR) in hyperthyroid (r=+0.63, p less than 0.01) and hypothyroid patients (r=+0.61, p less than 0.05). Elimination of the effect of the free thyroxine index (FT4I) on the total correlation between BMR and FT3I by partial correlation analysis gave partial r=+0.60, p less than 0.01 in hyperthyroid patients and partial r=+0.43, p less than 0.1 in hypothyroid patients. The FT4I did not correlate to BMR in either hyper- or hypothyroid patients. These results point to triiodothyronine as the major regulator of BMR in hyper- and hypothyroidism.

Sumatriptan Does Not Affect Arteriovenous Oxygen Differences in Jugular and Cubital Veins in Normal Human Subjects

Arteriovenous anastomoses (AVAs) may open up during migraine attacks. In studies with anaesthetized and bilaterally vagosympatectomized pigs, triptans reduce AVA blood flow and increase the arteriovenous O2 difference (AVDO2). To investigate whether subcutaneous sumatriptan 6 mg could induce changes in the AVDO2, we measured the AVDO2 in the external jugular vein in healthy subjects. We also measured the AVDO2 in the internal jugular and cubital veins. There were no changes in AVDO2 after subcutaneous sumatriptan, probably because AVA blood flow is limited in humans with an intact sympathetic nervous system.

Effect of a community screening for Helicobacter pylori: a 5-Yr follow-up study

BACKGROUND

Helicobacter pylori (H. pylori) screening and eradication may reduce the incidence of gastric cancer, AND AIMS: peptic ulcer, and ulcer complications, and it may reduce symptoms in a small proportion of individuals with functional dyspepsia. This study aimed to assess the effect of community H. pylori screening and treatment on the prevalence of dyspepsia, and as secondary outcomes, the effect on dyspepsia-related health-care consumption and quality of life over 5 yr.

METHODS

In 1998-1999, individuals aged 40-65 yr were randomized to H. pylori screening and treatment or to the control group. Five years later, the participants were sent a questionnaire to assess the prevalence of dyspepsia and quality of life. In addition, we obtained information from registers on the use of endoscopies and prescription medication. An economic evaluation was done alongside the randomized trial.

RESULTS

Of 12,530 participants attending the study at baseline, 11,065 (88%) were traced and contacted at the 5-yr follow-up. The response rate was 94%. At baseline, 17.5% in the screened group were H. pylori-positive. The absolute reduction in dyspepsia during the first year was 4% in the screened group, whereas no change was observed in the unscreened group; this rate remained constant during the next 4 yr. Quality of life did not change. A small effect was found for dyspepsia-related consultations and sick leave days, but not on the prescription rate of ulcer drugs. A 33% lower ulcer incidence (107 ulcers vs 148 ulcers) was seen in the screened group compared to the unscreened group.

CONCLUSION

A population H. pylori screening and treatment program in an H. pylori low-prevalence area had only a modest, but insignificant, effect on the rate of dyspepsia, and a modest, significant effect on the consultation rate and sick leave days for dyspepsia, but resulted in a decreased ulcer incidence. The intervention resulted in an increased cost due to H. pylori screening and treatment.

Spironolactone use and the risk of upper gastrointestinal bleeding: a population-based case-control study

AIMS

Recent studies have suggested an increased risk of upper gastrointestinal bleeding (UGB) in spironolactone users. The aim was to confirm the association, identify the risk factors and quantify the absolute risk.

METHODS

A population based case-control study was conducted in the County of Funen, Denmark. Cases (n = 3652) were all subjects with a first discharge diagnosis of serious UGB during the period 1995 to 2006. Age- and gender-matched controls (10 for each case) (n = 36 502) were selected by risk set sampling. Data on all subjects' drug exposure and past medical history were retrieved from a prescription database and from the County's patient register. Confounders were controlled by conditional logistic regression.

RESULTS

The adjusted odds ratio (OR) associating current use of spironolactone with UGB was 2.7 [95% confidence interval (CI) 2.2, 3.2]. The risk increased with higher doses of spironolactone (5.4; 3.4, 8.6) for 100-mg tablets. No trend was found with increasing cumulative dose. The strongest association was found among users aged 55-74 years (OR 13.1; 6.5, 26.3). Current use of loop diuretics was also associated with an increased risk of UGB (1.9; 1.7, 2.1).

CONCLUSION

The use of spironolactone is associated with increased risk of UGB. The risk increases with higher doses.

Familial hemiplegic migraine type 1 shows no hypersensitivity to nitric oxide

Familial hemiplegic migraine type 1 (FHM-1) is a dominantly inherited subtype of migraine with aura and transient hemiplegia associated with mutations in the CACNA1A gene. FHM-1 shares many phenotypical similarities with common types of migraine, indicating common neurobiological pathways. Experimental studies have established that activation of the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway plays a crucial role in migraine pathophysiology. Therefore, we tested the hypothesis that CACNA1A mutations in patients with FHM-1 are associated with hypersensitivity to NO-cGMP pathway. We included eight FHM-1 patients with R583Q and C1369Y mutations and nine healthy controls, who received intravenous infusions of 0.5 microg kg(-1) min(-1) glyceryl trinitrate (GTN) over 20 min. We recorded: headache intensity on a verbal rating scale; mean flow velocity in the middle cerebral artery (V(meanMCA)) by transcranial Doppler; diameter of the superficial temporal artery (STA) by Dermascan. One patient reported migraine without aura 5 h after start of the GTN infusion. No aura was reported. The AUC(headache) in the immediate phase was more pronounced in patients than in controls (P = 0.01). In the 14 h following GTN infusion, there was no difference in the AUC(headache) between patients and controls (P = 0.17). We found no difference in the AUC(VmeanMCA) (P = 0.12) or AUC(STA) (P = 0.71) between FHM-1 patients and controls. None of the control persons reported migraine-like headache. FHM-1 patients do not show hypersensitivity of the NO-cGMP pathway, as characteristically seen in migraine patients with and without aura. This indicates that the pathophysiological pathways underlying migraine headache in FHM-1 may be different from the common types of migraine.

Vasoactive Intestinal Peptide Causes Marked Cephalic Vasodilation, but does not Induce Migraine

We hypothesized that intravenous infusion of the parasympathetic transmitter, vasoactive intestinal peptide (VIP), might induce migraine attacks in migraineurs. Twelve patients with migraine without aura were allocated to receive 8 pmol kg-1 min-1 VIP or placebo in a randomized, double-blind crossover study. Headache was scored on a verbal rating scale (VRS), mean blood flow velocity in the middle cerebral artery ( Vmean mca) was measured by transcranial Doppler ultrasonography, and diameter of the superficial temporal artery (STA) by high-frequency ultrasound. None of the subjects reported a migraine attack after VIP infusion. VIP induced a mild immediate headache (maximum 2 on VRS) compared with placebo ( P = 0.005). Three patients reported delayed headache (3-11 h after infusion) after VIP and two after placebo ( P = 0.89). Vmean mca decreased (16.3 ± 5.9%) and diameter of STA increased significantly after VIP (45.9 ± 13.9%). VIP mediates a marked dilation of cranial arteries, but does not trigger migraine attacks in migraineurs. These data provide further evidence against a purely vascular origin of migraine.

Familial hemiplegic migraine type 2 does not share hypersensitivity to nitric oxide with common types of migraine

Familial hemiplegic migraine type 2 (FHM-2) and common types of migraine show phenotypic similarities which may indicate a common neurobiological background. The nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway plays a crucial role in migraine pathophysiology. Therefore, we tested the hypothesis that ATP1A2 mutations in patients with FHM-2 are associated with hypersensitivity to NO-cGMP pathway. Eight FHM-2 patients with R202Q, R763C, V138A and L764P mutations and nine healthy controls received intravenous infusions of 0.5 mug kg(-1) min(-1) glyceryl trinitrate (GTN) over 20 min. We recorded the following variables: headache intensity on a verbal rating scale; mean flow velocity in the middle cerebral artery (V(meanMCA)) by transcranial Doppler; diameter of the superficial temporal artery (STA) by ultrasound. The primary end-points were differences in incidence of migraine headache and area under the curve (AUC) for headache score during an immediate phase (0-120 min) and a delayed phase (2-14 h) after start of infusion. We found no difference in the incidence of reported migraine between FHM-2 patients, 25% (two out of eight), and controls, 0% (0 out of nine) (95% confidence interval -0.06, 0.56) (P = 0.21). The AUC(headache) in the immediate (P = 0.37) and delayed (P = 0.09) phase was not different between patients and controls. The GTN infusion resulted in a biphasic response in patients. During the immediate phase, the median peak headache occurred at 30 min and tended to be higher in patients, 1 (0, 3.8), than in controls, 0 (0, 1) (P = 0.056). During the delayed phase, the median peak headache occurred 4 h after the start of the infusion and was significantly higher in patients, 2.5 (0, 3), than in controls, 0 (0, 0) (P = 0.046). We found no difference in the AUC(VmeanMCA) (P = 0.77) or AUC(STA) (P = 0.53) between FHM-2 patients and controls. GTN infusion failed to induce more migraine in FHM-2 patients than in controls. The pathophysiological pathways underlying migraine headache in FHM-2 may be different from the common types of migraine.

The validity of a symptom diary in ratings of dyspepsia measured against a detailed interview: do patients and clinicians agree in their assessment of symptoms?

BACKGROUND

Patients' self-assessment of symptoms is central in drug treatment trials of functional dyspepsia. The validity of such ratings is important.

AIM

To validate a diary for monitoring severity and duration of dyspepsia.

METHOD

We compared the diary-cards with two clinicians' ratings of the patient's open-ended responses to the same questions administered by interview. Agreements were evaluated by estimation of the overall agreement and weighted kappa values (Kw).

RESULTS

Forty-six patients were evaluated. The Kw between the two clinicians rating severity and duration of symptoms were 0.59 and 0.86, respectively. Overall agreement between patients' diary rating and clinicians' consensus rating of severity were 52%, and a moderate agreement with Kw of 0.49 was found. For duration of symptoms the overall agreement and Kw were 67% and 0.59, respectively. Qualitative data revealed useful insight in the possible causes of suboptimal agreement between patients and clinicians.

CONCLUSIONS

We found a moderate to good agreement between patient and observer ratings, indicating that patients to a reasonable extent interpret severity and duration of dyspeptic symptoms in the same way as do investigators. A ceiling effect of the duration scale indicates suboptimal response categories, which should be adjusted before further use.

Magnetic resonance angiography shows dilatation of the middle cerebral artery after infusion of glyceryl trinitrate in healthy volunteers

Previous studies have reported dilatation of the middle cerebral artery (MCA) during acute glyceryl trinitrate (GTN)-induced headache, using imaging techniques such as transcranial Doppler (TCD), positron emission tomography (PET) and single photon emission computerized tomography (SPECT). In the present study we aimed to evaluate whether magnetic resonance angiography (MRA) may be used to examine the effect of GTN on the MCA, with respect to changes in diameter and cross-sectional area in healthy volunteers. In addition, we wanted to determine the intra- and inter-observer variation of the method. In a randomized, double blind, crossover study 12 healthy volunteers received intravenous infusion of GTN (0.5 microg/kg/min for 20 min) or placebo. Using 1.5 Tesla MRA, we recorded changes in the diameter and cross-sectional area of MCA before, during and after infusion of GTN. The MRA images were evaluated by two blinded, independent observers/neuroradiologists. The primary endpoints were the differences in the AUC for diameter and cross-sectional area of the MCA between the two experimental conditions and the intra- and inter-observer variation. The areas under the curve (AUC) of the MCA diameter and cross-sectional area were significantly greater after GTN than after placebo (P < 0.05). The intra-observer variation (day-to-day) at baseline was 8.3% and 10.9% for the two observers. The mean inter-observer variation of the cross-sectional MCA area was 15.5% and for the diameter measurements 8%. The present study shows that the MRA method gives a reliable semi-quantitative index of the vascular changes in the intra-cerebral arteries after infusion of GTN and may be useful for headache research.

Glutathione depletion modulates methanol, formaldehyde and formate toxicity in cultured rat conceptuses

The proposed use of methanol (H3COH) as an alternative to fossil fuels has prompted concern about potential health risks resulting from widespread environmental exposure. Methanol is teratogenic in rodents and, although the exact toxic species is not known, teratogenesis may result from the enzymatic biotransformation of H3COH to formaldehyde (CH2O) and formic acid causing increased biological reactivity and toxicity. A protective role for the antioxidant glutathione (GSH) has been described for H3COH, CH2O and formic acid toxicity in various biological systems but has yet to be evaluated in the developing conceptus. Whole embryo culture studies were conducted using GD 10-11 rat conceptuses to elucidate the relationship between H3COH and its metabolites and GSH status. Methanol exposure produced a decrease in normal growth parameters and a dose-dependent loss of viability. CH2O had deleterious effects on embryo growth and viability. Sodium formate (HCOONa) exposure resulted in a high mortality rate but viable embryos did not manifest any abnormalities. Methanol, CH2O, and HCOONa all produced a significant depletion of GSH in both embryo and VYS. Inhibition of GSH synthesis by L-buthionine-S,R-sulfoximine (BSO) treatment exacerbated H3COH, CH2O and HCOONa embryotoxicity. Interestingly, only H3COH/BSO and CH2O/BSO co-treatments caused increased malformation, while embryos treated with HCOONa/BSO did not produce any developmental deformities. These results implicate CH2O as the most embryotoxic H3COH metabolite, on a molar basis, in terms of causing dysmorphogenesis, alterations of normal growth parameters and embryolethality. HCOONa was selectively embryolethal and did not produce dysmorphogenesis. CH2O toxicity is potentiated by GSH depletion, indicating that GSH may be more directly involved in its detoxication in the embryo.

Spatial and temporal ontogenies of glutathione peroxidase and glutathione disulfide reductase during development of the prenatal rat

Spatial and temporal expression and regulation of the antioxidant enzymes, glutathione peroxidase (GSH-Px), glutathione disulfide reductase (GSSG-Rd) may be important in determining cell-specific susceptibility to embryotoxicants. Creation of tissue-specific ontogenies for antioxidant enzyme activities during development is an important first step in understanding regulatory relationships. Early organogenesis-stage embryos were grouped according to the somite number (GD 9-13), and fetuses were evaluated by gestational day (GD 14-21). GSH-Px activities in the visceral yolk sac (VYS) increased on consecutive days from GD 9 to GD 13, representing a 5.7-fold increase during this period of development. GSH-Px activities in VYS decreased after GD 13, ultimately constituting a 37% decrease at GD 21. Head, heart, and trunk specific activities generally increased from GD 9 to GD 13 albeit not to the same magnitude as detected in the VYS. GSSG-Rd activities showed substantial increases in the VYS from GD 9 to GD 13, 6.3-fold and decreased thereafter to 50% by GD 21. The greatest changes in enzyme activities were noted in the period between GD 10 and GD 11, where the embryo establishes an active cardiovascular system and begins to convert to aerobic metabolism. Generally, from GD 14-21, embryonic organ GSH-Px and GSSG-Rd activities either remained constant or increased as gestation progressed. These studies suggest the importance of the VYS in dealing with ROS and protecting the embryo. Furthermore, understanding the consequences of lower antioxidant activities during organogenesis may help to pinpoint periods of teratogenic susceptibility to xenobiotics and increased oxygen.

Altered differentiation in rat and rabbit limb bud micromass cultures by glutathione modulating agents

Glutathione (GSH) is the primary source of reducing equivalents in most cells, contributes significantly to the cellular redox potential and can control differentiation, proliferation, and apoptosis. Using limb bud micromass cultures from Sprague Dawley rats and New Zealand White rabbits, GSH modulating agents, L-buthionine-S,R-sulfoximine (BSO) and diethyl maleate (DEM) altered the formation of Alcian blue positive chondrogenic foci. Limb bud micromass cultures were treated for 5 d with BSO (50 or 100 microM) or DEM (5-25 microM). GSH content was determined by HPLC analysis. In rat cultures, BSO treatment did not affect differentiation but did show GSH depletion. In rabbit cultures, BSO completely inhibited differentiation and significantly depleted GSH. Treatment of rat cultures with DEM resulted in the dose-dependent decrease of chondrogenic foci, which correlated with a dose-dependent depletion of GSH. DEM completely inhibited rabbit limb bud cell differentiation and depleted GSH by 44%. Inhibition of differentiation was confirmed in rabbit cultures by the reduction in BMP-4 content. Addition of N-acetylcysteine to rabbit micromass cultures restored chondrogenic foci differentiation seen following treatment with both DEM and BSO. These results show species differences in GSH depletion in rat vs. rabbit limb bud cells and implicate GSH and cysteine in affecting pathways involved in chondrocyte differentiation.

[Prevention of NSAID induced gastroduodenal ulcers]

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are important agents in the management of arthritic and inflammatory conditions, and are among the most frequently prescribed medications in North America and Europe. However, there is overwhelming evidence linking these agents to a variety of gastrointestinal (GI) toxicities.

OBJECTIVES

To review the effectiveness of common interventions for the prevention of NSAID induced upper GI toxicity.

SEARCH STRATEGY

A literature search was conducted, according to the Cochrane methodology for identification of randomized controlled trials in electronic databases, including MEDLINE from 1966 to January 2000, Current Contents for 6 months prior to January 2000, Embase to February 1999, and a search of the Cochrane Controlled Trials Register from 1973 to 1999. Recent conference proceedings were reviewed and content experts and companies were contacted.

SELECTION CRITERIA

Randomized controlled clinical trials (RCTs) of prostaglandin analogues (PA), H2-receptor antagonists (H2RA) or proton pump inhibitors (PPI) for the prevention of chronic NSAID induced upper Gl toxicity were included.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted data regarding population characteristics, study design, methodological quality and number of patients with endoscopic ulcers, ulcer complications, symptoms, overall drop-outs, drop-outs due to symptoms. Dichotomous data was pooled using Revman V3.1. Heterogeneity was evaluated using a chi square test.

MAIN RESULTS

Thirty-three RCTs met the inclusion criteria. All doses of misoprostol significantly reduced the risk of endoscopic ulcers. Misoprostol 800 micrograms/day was superior to 400 micrograms/day for the prevention of endoscopic gastric ulcers (RR = 0.18, and RR = 0.38 respectively, p = 0.0055). A dose response relationship was not seen with duodenal ulcers. Misoprostol caused diarrhea at all doses, although significantly more at 800 micrograms/day than 400 micrograms/day (p = 0.0012). Misoprostol was the only prophylactic agent documented to reduce ulcer complications. Standard doses of H2RAs were effective at reducing the risk of endoscopic duodenal (RR = 0.24; 95%, CI: 0.10-0.57) but not gastric ulcers (RR = 0.73; 95% CI: 0.50-1.09). Both double dose H2RAs and PPIs were effective at reducing the risk of endoscopic duodenal and gastric ulcers (RR = 0.44; 95% CI: 0.26-0.74 and RR = 0.37; 95% CI: 27-0.51 respectively for gastric ulcer), and were better tolerated than misoprostol.

REVIEWERS' CONCLUSIONS

Misoprostol, PPIs, and double dose H2RAs are effective at preventing chronic NSAID related endoscopic gastric and duodenal ulcers. Lower doses of misoprostol are less effective and are still associated with diarrhea. Only misoprostol 800 micrograms/day has been directly shown to reduce the risk of ulcer complications.

Differential antioxidant enzyme activities and glutathione content between rat and rabbit conceptuses

Redox status regulates numerous cellular processes like transcription factor activation and binding, protein folding, and calcium sequestration. Because the most abundant reducing equivalent in the cell is glutathione (GSH), it could play a role for teratogens that cause oxidative stress and disrupt pathways involved in differentiation and proliferation. Investigation of the redox status of two species that have demonstrated differential sensitivity to teratogens represents a novel approach for determining the role of redox alteration in teratogenesis. Furthermore, examining specific regions of the embryo may also help to explain why certain tissues are uniquely sensitive, while others are resistant to oxidative insult. In the presented study, New Zealand White rabbit (GD 12) and Sprague Dawley rat embryos (GD 13) were removed from the uterus on days of similar development. Each embryo was dissected into three portions-the limbs, the head, and the trunk. Samples were placed in the appropriate buffers for the measurement of both direct and indirect redox status contributors-GSH, cysteine, thioredoxin, glutathione disulfide, protein-glutathione mixed disulfides, superoxide dismutase, glutathione peroxidase, and glutathione disulfide reductase. Species comparison of whole embryos indicated that the rabbit embryo possesses a higher redox potential (more oxidative) than the rat embryo. Findings, in general, show that the rabbit may be more sensitive to redox-altering teratogens because it is inherently more pro-oxidizing and may be more easily perturbed resulting in misregulation of cellular processes. Differences were most apparent in the limb as compared to the embryonic head and trunk, where the rabbit limb has a significantly more pro-oxidizing redox environment than the rat limb. Species comparisons like these may help in the understanding of how redox shifts affect cellular processes and would contribute to regulation of biochemical and molecular events that may be associated with mechanisms of teratogenesis. These may contribute to a more complete rationale for choosing a species for study and provide a better correlation with human developmental toxicants.

Identifying responders to acid suppression in dyspepsia using a random starting day trial

BACKGROUND

Functional dyspepsia is a heterogeneous condition and a uniform response to drug treatment is not likely. This may be the reason for the general failure of acid suppression in clinical trials in these patients. It may be more rewarding to identify true responders to drug treatment by a single subject trial.

AIM

To develop and to test a novel single subject trial design (random starting day trial) in dyspeptic patients.

PATIENTS AND METHODS

A total of 301 dyspeptic patients entered a 16-day trial. All patients received placebo for the first 4 days and switched to omeprazole at a randomized and blinded day between day 5 and day 14. Response was defined as a sustained >/= 50% decrease in symptom score occurring in relation to drug shifting.

RESULTS

Spontaneous response varied between 0.3% and 10.6% per day, uniformly distributed over time. Overall, 53-61% of patients with organic dyspepsia had a symptom response in relation to shifting to active treatment, compared to only 23% of patients with functional dyspepsia. The only predictor of response was symptoms suggesting gastro-oesophageal reflux.

CONCLUSIONS

A random starting day trial may be a valuable tool to identify response to acid suppression in dyspeptic patients.

Developmental toxicity of carbon black oil in mice

BACKGROUND

Carbon black oil (CBO) is a refinery side-stream product used to produce asphalt and other commercial products. CBO contains several classes of hydrocarbons, several of which are known to exhibit systemic and gestational toxicities, making this mixture a candidate for causing reproductive toxicity.

METHODS

Swiss-Webster mice were administered CBO (300, 350, 400 mg/kg/day) via oral gavage in a dosage volume of 10 microl/g body weight on gestation days (GD) 6-15. Uterine contents were evaluated on GD 18.

RESULTS

Treatment with CBO at all dosage levels resulted in a high frequency of maternal clinical symptoms and a decrease in maternal weight gain. Decreased fetal viability was observed, manifested as a decrease in viable implants and, in a high percentage of treated dams, as early resorption of the entire litter. A significant reduction in fetal weight was also observed. However, neither structural malformations nor developmental delays in ossification were observed in any of the living offspring. To minimize maternal toxicity, the dosage range was lowered (100, 200, 300 mg/kg/day), and the concentration was adjusted such that the volume administered to each dam was decreased by 20%. In this trial, the only maternal effect observed was an increase in maternal liver weight at 200 and 300 mg/kg. The fetal lethality effects observed previously were reduced substantially. Nevertheless, the frequency of resorption among all treatment groups was higher statistically than in controls.

CONCLUSIONS

These data support the hypothesis that CBO is reproductively toxic in Swiss-Webster mice at oral doses of >/=100 mg/kg/day.

Effects of nitric oxide blockade and cyclosporin A on cardiovascular and renal function in normal man

OBJECTIVE

The present study investigated whether the nitric oxide (NO) system is involved in cyclosporin A (CsA)-induced changes in cardiovascular and renal function in man.

SUBJECTS AND METHODS

Ten healthy volunteers were investigated twice--with and without intake of a single dose of CsA (8 mg/kg). N(G)-monomethyl-L-arginine (L-NMMA; 3 mg/kg) was injected 4 h after study start on each day.

RESULTS

There was no change in glomerular filtration rate (GFR) on the day without CsA. CsA alone did not change GFR, but after L-NMMA injection, GFR decreased significantly from 101 +/- 4 to 91 +/- 4 ml/min. L-NMMA increased renal vascular resistance with no difference between the two study days. CsA increased significantly the diastolic blood pressure (BP) by 8 +/- 2% and the heart rate (HR) by 30 +/- 4%, without changes in cardiac output L-NMMA further increased BP by around 8%, and decreased HR by 11% and cardiac output by 20% on both study days. L-NMMA decreased urinary flow rate by around 25% and renal sodium clearance from 1.1 to approximately 0.6 ml/min on both study days. CsA decreased plasma renin significantly and increased the urinary excretion rate of prostaglandin E2 (PgE2), 6-keto-prostaglandin F1alpha (6-keto-PgF1alpha) and thromboxane B2(TxB2) when compared to the control day. The urinary excretion rate of NOx and cGMP declined gradually on the control day. In contrast, there was a minor, non-significant increase in NOx and cGMP excretion after CsA, followed by a decrease (29 +/- 2 and 16 +/- 4%, respectively) after L-NMMA in parallel with the decrease in GFR.

CONCLUSION

The present findings suggest that NO does not play a major role during acute CsA-induced changes in cardiovascular function and renal haemodynamics in man. Renal NO synthesis, however, may attenuate the acute CsA-induced decrease in GFR.

Blood pressure and plasma catecholamines in acute and prolonged hypoxia: effects of local hypothermia

This study measured the pressor and plasma catecholamine response to local hypothermia during adaptation to hypobaric hypoxia. Eight healthy men were studied at rest and after 10 and 45 min of local cooling of one hand and forearm as well as after 30 min of rewarming at sea level and again 24 h and 5 days after rapid, passive transport to high altitude (4,559 m). Acute mountain sickness scores ranged from 5 to 16 (maximal attainable score: 20) on the first day but were reduced to 0-8 by the fifth day. Systolic blood pressure, heart rate, and plasma epinephrine increased on day 1 at altitude compared with sea level but declined again on day 5, whereas diastolic and mean blood pressures continued to rise in parallel with plasma norepinephrine. With local cooling, an increased vasoactive response was seen on the fifth day at altitude. Very high pressures were obtained, and the pressure elevation was prolonged. Heart rate increased twice as much on day 5 compared with the other two occasions. Thoracic fluid index increased with cooling on day 5, suggesting an increase in pulmonary vascular resistance. In conclusion, prolonged hypoxia seems to elicit an augmented pressor response to local cooling in the systemic and most likely also the pulmonary circulation.

Differential alteration by thalidomide of the glutathione content of rat vs. rabbit conceptuses in vitro

Thalidomide has been shown to cause limb reduction defects in rabbits with much greater potency than in rats, possibly due to inherent biochemical differences between the two species. Whole embryo culture was used to make direct comparisons between thalidomide-sensitive New Zealand White rabbits and thalidomide-resistant Sprague-Dawley rats, focusing on the possible roles of glutathione (GSH) and cysteine in mechanisms of thalidomide teratogenicity. Conceptuses were treated by adding thalidomide (0, 5, 15, and 30 microM) directly to the culture media containing conceptuses of similar gestational stages. Embryos and visceral yolk sacs (VYS) were measured for changes in GSH and cysteine content using HPLC after 24 h of exposure in vitro. Thalidomide-induced (15 and 30 microM) depletion of VYS GSH occurred only in the rabbit, where GSH concentrations (pmol/microg protein) fell significantly to about 50% of control. Rat VYS did not show a significant GSH depletion at any thalidomide concentration tested. Comparison between species showed that the control rabbit VYS contained 35% less GSH than the control rat VYS. Control rat embryos and control rabbit embryos contained similar concentrations of GSH, but thalidomide treatment preferentially depleted GSH in the rabbit at lower thalidomide concentrations (5 micro/M). Cysteine concentrations were not significantly altered from control in the embryo or VYS of either species when treated with thalidomide. However, although control cysteine concentrations did not differ significantly between rat and rabbit VYS, control cysteine levels in rabbit embryos were 65% lower than those in control rat embryos. Rabbit conceptuses displayed lower species-specific GSH and cysteine levels and a greater propensity for thalidomide-induced GSH depletion than in rat conceptuses, consistent with the greater sensitivity of the rabbit to thalidomide teratogenicity. These thalidomide-induced and inherent species differences implicate a possible role for GSH and redox status in the mechanisms of thalidomide teratogenicity.

Non-steroidal anti-inflammatory drugs and renal response to exercise: a comparison of indomethacin and nabumetone

Nabumetone, a newer non-steroidal anti-inflammatory drug (NSAID) which preferentially blocks cyclo-oxygenase-2 activity, may be less nephrotoxic than indomethacin. This study tested whether nabumetone has effects different from those of indomethacin on exercise-induced changes in renal function and the renin-aldosterone system. In a randomized fashion, ten subjects were studied after indomethacin (100 mg), nabumetone (1 g) or no medication (control) administered orally at 22.00 hours on the day before each study day, and again at 8.00 hours upon arrival at the laboratory. Renal function was studied at baseline, during graded 20-min exercise sessions at 25%, 50% and 75% of the maximal oxygen uptake rate, and subsequently during two 1-h recovery periods. Heart rate, arterial blood pressure, cardiac output and plasma catecholamines at rest and during exercise were not altered by indomethacin or nabumetone. Indomethacin decreased urinary rates of excretion of 6-oxo-prostaglandin F(1alpha) (6-oxo-PGF(1alpha)) and thromboxane B(2) in all study periods. Nabumetone decreased 6-oxo-PGF(1alpha) excretion during and after exercise. Excretion rates for PGE(2) did not change. Neither indomethacin nor nabumetone changed baseline values or exercise-induced decreases in renal plasma flow or glomerular filtration rate. Indomethacin, but not nabumetone, decreased sodium excretion, urine flow rate and free water clearance. The renal response to exercise, however, remained unchanged. In contrast with nabumatone, indomethacin decreased the plasma renin concentration. Thus, during exercise, nabumetone may decrease the excretion of 6-oxo-PGF(1alpha) by inhibition of cyclo-oxygenase-1 or by inhibition of specific exercise-induced activation of cyclo-oxygenase-2, or both. None of the drugs changed the renal response to exercise. Inhibition by indomethacin of angiotensin II and thromboxane A(2) synthesis may, during exercise, counterbalance renal vasoconstriction caused by blockade of vasodilatory prostaglandins.

Radioiodine therapy for multinodular toxic goiter

BACKGROUND

Radiolabeled iodine 131 therapy is used for treatment of multinodular toxic goiter, but long-term follow-up studies are lacking.

METHODS

A prospective study of 130 consecutive patients (115 women) treated with 131I for multinodular toxic goiter and followed by evaluation of thyroid volume (determined using ultrasound) and thyroid function variables.

RESULTS

The patients were observed for a median of 72 months (range, 12-180 months). Sixty-six patients received antithyroid drug pretreatment; 64 did not. Iodine 131 treatment (3.7 MBq/g thyroid tissue corrected to a 100% 24-hour 131I uptake) was given as a single dose in 81 patients, 2 doses in 38, and 3 to 5 doses in 11. One or 2 treatments cured 119 patients (92%), and 68 (52%) became euthyroid within 3 months after 131I treatment. The median 131I dose was 370 MBq (range, 93-1850 MBq). Forty-nine patients needing more than 131I dose had a reduction in median thyroid volume from 56 mL (range, 21-430 mL) to 44 mL (range, 15-108 mL), representing a 24% reduction related to the insufficient 131I dose. In all patients, the initial median thyroid volume of 44 mL (range, 16-430 mL) decreased to 25 mL (range, 8-120 mL) (P<.005), representing a median reduction of 43%, 24 months after the last 131I dose. Hypothyroidism evaluated using life-table analysis developed in 6% of patients who did not receive antithyroid pretreatment and 20% who did (P<.005) after a median of 42 months (range, 3-60 months), the total hypothyroidism frequency being 14% within 5 years of treatment.

CONCLUSIONS

Ninety-two percent of patients with multinodular toxic goiter were cured with 1 or 2 treatments. The thyroid volume was reduced by 43%, with few side effects. Iodine 131 should be the choice of treatment in patients with multinodular toxic goiter.

Transition of nodular toxic goiter to autoimmune hyperthyroidism triggered by 131I therapy

The use of 131I treatment in nodular toxic goiter is widely accepted. In this article, we describe transition of nodular toxic goiter into an autoimmune toxic goiter with development of thyrotropin receptor antibodies (TRAb) as a side effect of 131I treatment. In this retrospective study, 149 patients with nodular toxic goiter (100 with multinodular goiter, 49 with a solitary autonomously functioning toxic nodule) were studied. Of these 149 patients 100 became permanently euthryoid after 1 dose of 131I, and due to persistent hyperthyroidism, 32 patients needed 2-5 doses to became euthyroid. After becoming euthyroid, none of these 132 patients had relapse of hyperthyroidism in the follow-up period. Based on evaluation of the thyroid hormone variables, 17 of 149 patients had a distinctly different pattern in the changes in thyroid hormones. They developed an increase in FT4I 3-6 months posttreatment after an initial fall in FT4I. Twelve of these 17 patients were treated with antithyroid drugs before the initial 131I dose. On samples of frozen sera (-20 degrees C) anti-thyroid peroxidase (TPO) and TRAb were followed for 6 months after 131I treatment in these 17 patients. A similar follow-up was done in 20 patients (10 with and 10 without antithyroid drug pretreatment), randomly selected from the patients who did not relapse. In the remaining 112 patients, anti-TPO and TRAb levels were measured only before the 131I treatment. Of the 17 patients with relapse, 6 developed TRAb concomitant with recurrence of hyperthyroidism (4% of the study group). In 5 of the 17 patients TRAb values remained absent throughout the follow-up period. The remaining 6 patients had elevated TRAb values before 131I treatment. Among the 132 patients who did not relapse, an additional 7 cases with presence of TRAb were found. A total of 9% of the study group was found to have TRAb before 131I pretreatment. Anti-TPO was found in 20 of 149 patients (13%) before 131I treatment. Complications, either hypothyroidism or TRAb-associated hyperthyroidism, were seen in 8 of 20 patients (40%) with anti-TPO before 131I treatment, compared to 9 of 129 (7%) without (p<0.005). In conclusion, TRAb and a Graves' like hyperthyroidism can be triggered by 131I treatment in patients with nodular toxic goiter. The presence of anti-TPO seem to be a marker of an increased risk of development of TRAb-associated hyperthyroidism as well as hypothyroidism, but both side effects can be seen despite the absence of anti-TPO autoantibodies.

Long-term effect of radioactive iodine on thyroid function and size in patients with solitary autonomously functioning toxic thyroid nodules

OBJECTIVE

To investigate the long-term effects of radioiodine (131I) on thyroid function and size in patients with a solitary toxic thyroid nodule.

DESIGN

Prospective study of patients treated for a solitary autonomous toxic nodule, followed by evaluation of thyroid volume and function.

PATIENTS

Sixty-two consecutive patients followed for a minimum of 12 months (range 12-168, median 60). Seventeen patients received antithyroid drug treatment before 131I.

MEASUREMENTS

Standard thyroid function variables and ultrasonically determined thyroid volume before as well as 0.75, 1.5, 3, 6 and 12 months after treatment, and then once a year were investigated.

RESULTS

131I treatment (3.7 MBq/g thyroid tissue corrected to a 100% 24-h 131I uptake) was given as a single dose in 53 patients; six needed two doses and another three were given 3-5 131I treatments. The median initial dose was 310 MBq (140-666) and the median total dose was 332 MBq (148-1576). In patients receiving one 131I treatment (n = 53) the total thyroid volume decreased significantly from a median of 40 ml (range 19-77) to 24 ml (8-50) within 3 months. This represented a median reduction of 35%. A further significant decrease was seen after 24 months to a total reduction of 45%. In patients given more than one dose the thyroid volume was reduced from a median of 45 ml (19-104) before treatment to 30 ml (14-50) after a follow-up of 60 months (9-132) after the last 131I treatment. Patients without antithyroid pretreatment, receiving one 131I treatment (n = 39) became euthyroid after a median of 1.5 months (0.75-9) after treatment. Seventy-five per cent were euthyroid within 3 months. In patients pretreated with antithyroid drugs and treated with one dose of 131I (n = 14) euthyroidism was achieved after a median of 12 months (0.75-24) after 131I treatment. Hypothyroidism developed in five patients (8%) after a median of 36 months (6-60) after 131I treatment.

CONCLUSION

A cure-rate of 75% within 3 months is seen when treating autonomous solitary toxic thyroid nodules with 131I. The thyroid volume is reduced by 35% within 3 months and 45% after 2 years. Side-effects are few and consist of hypothyroidism in less than 10% with a median follow-up of 5 years. This treatment should be regarded as the standard treatment for this condition until prospective comparisons with surgery and ethanol injection therapy have been performed.

Is routine thyroxine treatment to hinder postoperative recurrence of nontoxic goiter justified?

Previous reports regarding the efficacy of levo-T4 (L-T4) in preventing postoperative recurrence of nontoxic goiter have been controversial. This study was designed to evaluate the influence of long-term L-T4 treatment on thyroid volume after thyroidectomy for nontoxic goiter. We studied 202 consecutive patients operated on for benign nontoxic goiter and followed them for a minimum of 12 months (median, 10 yr; range, 1-14 yr). Three months after thyroidectomy, patients were randomized to L-T4 treatment (group A, n = 100) with an initial dose of 150 microg daily and to no treatment (group B, n = 102). All were clinically and biochemically euthyroid, and preoperatively none were taking any thyroid and/or antithyroid medication. Standard thyroid function variables and ultrasonically determined thyroid volume (normal range, 9-28 mL) were determined before and 3 and 12 months after randomization and yearly thereafter. Recurrence was defined as an ultrasonically enlarged thyroid gland. Clinical data were similar between the two groups. Incidence of recurrence in group A was 19/100 (21%; 95% CL 0-42%; life-table analysis) and in group B 27/102 (35%; CL 7-64%) (P = 0.16) and was related to removed amount, remnant size, and pathoanatomical diagnosis but not type of operation or postoperative level of serum TSH and T4. L-T4 dose had to be reduced in 36 of 100 patients because of side effects of the treatment. In conclusion, the possible benefits of L-T4 treatment should be weighed against the possible side effects. Our study does not support the routine postoperative use of L-T4.

Effects of hyperventilation and hypocapnic/normocapnic hypoxemia on renal function and lithium clearance in humans

BACKGROUND

Using the renal clearance of lithium as an index of proximal tubular outflow, this study tested the hypothesis that acute hypocapnic hypoxemia decreases proximal tubular reabsorption to the same extent as hypocapnic normoxemia (hyperventilation) and that this response is blunted during normocapnic hypoxemia.

METHODS

Eight persons were studied on five occasions: (1) during inhalation of 10% oxygen (hypocapnic hypoxemia), (2) during hyperventilation of room air leading to carbon dioxide values similar to those with hypocapnic hypoxemia, (3) during inhalation of 10% oxygen with the addition of carbon dioxide to produce normocapnia, (4) during normal breathing of room air through the same tight-fitting face mask as used on the other study days, and (5) during breathing of room air without the face mask.

RESULTS

Hypocapnic and normocapnic hypoxemia and hyperventilation increased cardiac output, respiratory minute volume, and effective renal plasma flow. Glomerular filtration rate remained unchanged on all study days. Calculated proximal tubular reabsorption decreased during hypocapnic hypoxemia and hyperventilation but remained unchanged with normocapnic hypoxemia. Sodium clearance increased slightly during hypocapnic and normocapnic hypoxemia, hyperventilation, and normocapnic normoxemia with but not without the face mask.

CONCLUSIONS

The results indicate that (1) respiratory alkalosis with or without hypoxemia decreases proximal tubular reabsorption and that this effect, but not renal vasodilation or natriuresis, can be abolished by adding carbon dioxide to the hypoxic gas; (2) the increases in the effective renal plasma flow were caused by increased ventilation rather than by changes in arterial oxygen and carbon dioxide levels; and (3) the natriuresis may be secondary to increased renal perfusion, but application of a face mask also may increase sodium excretion.