bluuebunny/crossref_metadata_2025 huggingface dataset:
Additional value of measurement of urinary cortisone and unconjugated cortisol metabolites in assessing the activity of 11β‐hydroxysteroid dehydrogenase in vivo
Authors: Best Ruth , Walker Brian R.
Published: November 2003

OBJECTIVE

It has been shown recently that 11β‐hydroxysteroid dehydrogenase (11β‐HSD) is expressed as at least 2 isozymes. In the liver, 11β‐HSD1 converts cortisone to cortisol; in the kidney, 11β‐HSD2 converts cortisol to cortisone. Conventional assessment of 11β‐HSD activity in vivo has relied on gas chromatographic measurement of the ratios of conjugated cortisol and cortisone metabolites. However, these do not permit distinction between the tissue‐specific activities of the enzymes and do not reflect all forms of 11β‐HSD deficiency. In this report, we have assessed the usefulness of measuring unconjugated cortisol metabolites and free cortisol and cortisone in urine as indices of renal 11β‐HSD activity in man.

DESIGN

Six healthy male subjects established in sodium balance were given either glycyrrhetinic acid (170 mg t.d.s., to inhibit 11β‐HSD2), carbenoxolone (100 mg t.d.s., to inhibit both 11β‐HSD1 and 11β‐HSD2) or both inhibitors in combination.

MEASUREMENTS

Urinary electrolytes were measured and the concentrations of total and unconjugated urinary cortisol and its metabolites were determined by gas chromatography mass spectrometry.

RESULTS

Glycyrrhetinic acid and carbenoxolone inhibited renal 11β‐HSD2 to a similar degree, as judged by similar sodium retention. As previously reported, conventional measurement of ratios of total cortisol to cortisone metabolites were influenced to a greater extent by glycyrrhetinic acid (100–200% increase in ratio from baseline) than by carbenoxolone (< 30% increase). However, the effect of carbenoxolone was readily detected by measurement of urinary unconjugated cortisol/cortisone (130–480% increase of ratio from baseline) and also by measurement of ratios of unconjugated cortisol metabolites (60–130% increase).

CONCLUSIONS

Measurement of free cortisol and cortisone in urine provides the most sensitive index of renal 11β‐HSD activity. Measurement of total and conjugated urinary steroids is insensitive in circumstances where 11β‐HSD activity in liver or elsewhere may be abnormal.
Strong association between serum levels of leptin and testosterone in men
Authors: Behre Hermann M. , Simoni Manuela , Nieschlag Eberhard
Published: November 2003

OBJECTIVE

Leptin serves as a hormonal signal linking food intake and energy expenditure to fat mass. As significant effects of testosterone administration on body composition and adipose tissue have been described recently, we examined a possible association between serum levels of leptin and testosterone which has not been reported so far.

SUBJECTS

Three groups comprising a total of 58 adult age‐matched males were included in this cross‐sectional analysis by computer‐assisted clinical database selection. Group 1 (n=22) consisted of untreated hypogonadal patients with testosterone serum levels lower than 7 nmol/l. The inclusion criterion for Groups II (n=20) and III (n=16) was a serum testosterone level higher than 30 nmol/l. Group II involved hypogonadal patients under effective androgen substitution therapy; Group III comprised males without any endocrine disorder attending our clinic.

MEASUREMENTS

Morning blood samples were taken for determination of serum levels of leptin, testosterone, oestradiol and sex‐hormone binding globulin (SHBG). Serum levels of leptin were measured by homologous radioimmunoassay, the other hormones by standard immunoassays.

RESULTS

No significant differences in serum leptin, serum testosterone, and body mass index (BMI) were detected between Group II (3.7 ± 1.5 μg/l, 40.3 ± 7.6 nmol/l, 24.4 ± 4.9 kg/m2, respectively (mean ± SD)), and Group III (4.0 ± 2.0 μg/l, 35.9 ± 6.5 nmol/l, 24.8 ± 2.6 kg/m2, respectively). However, hypogonadal patients of Group I who were selected for low testosterone serum levels (4.3 ± 1.7 nmol/l) had significantly higher leptin serum levels of 18.8 ± 9.7 μg/l (P < 0.001) and significantly higher BMI of 30.0 ± 6.6 kg/m2 (P < 0.001). Multiple linear regression analysis revealed a significant independent association of leptin with testosterone serum levels (partial correlation coefficient = − 0.84; P < 0.001) and with BMI (partial correlation coefficient = 0.44; P= 0.001), whereas serum levels of oestradiol and SHBG had no additional influence.

CONCLUSIONS

This study demonstrates a close association between serum levels of testosterone and leptin in males which has not been described previously.

Serum testosterone levels could be an important contributor to the known gender difference in serum leptin levels which can be found even after correction for body composition. These findings might be of clinical relevance for testosterone substitution therapy of hypogonadal as well as ageing men.
Genomic sequence analysis of a key residue (Arg183) in human Gαq in invasive non‐functional pituitary adenomas
Authors: Farrell W. E. , Talbot J. A. , Bicknell E. J. , Simpson D. , Clayton R. N.
Published: November 2003

OBJECTIVE

With isolated exceptions the only oncogene significantly associated with pituitary tumours is a constitutively active Gs protein (Gαs). The recent cloning of the cDNA of human Gαq has facilitated the study of this activator of the phospholipase Cβ/Ca2+/protein kinase C pathway. Since, with isolated exceptions, non‐functional tumours are responsive in vitro to TRH and GnRH which activate Gq, we have investigated the genomic sequence of Gαq, in non‐functional (NF) invasive pituitary adenomas, at a residue corresponding to the one most frequently mutated in Gαs.

PATIENTS AND MEASUREMENTS

We studied 27 invasive NF pituitary tumours by direct sequencing of DNA derived from archival slide extracted tumour cells. Primers were designed to encompass Arg183 (corresponding to Arg201 of Gαs) which when mutated has been shown to have oncogenic potential when transfected into cultural rat fibroblasts. In a previous study we have described allelic loss at tumour suppressor gene loci (TSG) in 7 of these 27 tumours.

RESULTS

We successfully amplified genomic DNA with primers designed from the cDNA sequence of Gαq with specific exclusion of a processed pseudogene. No mutations were found at Arg183, in either the tumours showing allelic losses at specific TSG loci, or in the 20 remaining tumours in which we found no losses at the TSG loci investigated.

CONCLUSIONS

Mutations at this key residue in Gαq occur infrequently, if at all, in invasive non‐functional pituitary tumours. However we cannot exclude the possibility of mutation(s) at the other key residue of Gαq, Gln209, implicated in GTP hydrolysis, or in other components of this pathway.
The role of intravenous administration of dextran 70 in enteric bacterial translocation after partial hepatectomy in rats
Authors: WANG X.O. , SUN Z.W. , SOLTESZ V. , DENG X.M. , ANDERSSON R.
Published: November 2003

The aim of this study was to assess the effect of intravenous dextran on bacterial translocation and intestinal vascular endothelial and epithelial barrier function after experimental partial hepatectomy. We determined systemic arterial pressure, enteric bacterial growth (proximal and distal small intestine and colon) and bacterial translocation (BT) to mesenteric lymph nodes (MLN), liver, lungs, spleen, kidneys and blood, as well as intestinal vascular endothelial and epithelial barrier permeability, after sham operation or partial hepatectomy (50% and 90%) with preoperative intravenous administration of saline, albumin or dextran 70. Subtotal hepatectomy induced a significant decrease in arterial pressure and an increase in the number of Escherichia coli in the distal small intestine. BT was not observed in sham‐operated animals or in rats with 50% hepatectomy administered dextran. The number of positive cultures of enteric bacteria was significantly increased after hepatectomy, whereas dextran treatment decreased the number of animals with BT. Increased permeability of the intestinal vascular endothelial and epithelial barriers was noted in hepatectomized animals, while dextran prevented hepatectomy‐induced vascular endothelial barrier injury. Enteric bacterial translocation occurred following partial hepatectomy in the rat, associated with bacterial overgrowth in the distal small intestine. Intravenous administration of dextran 70 prevented bacterial overgrowth and translocation, at least in part, by maintaining gut vascular endothelial barrier integrity.
Detection and quantification of the control proteins of the alternative pathway of complement in 3T3‐L1 adipocytes
Authors: PEAKE P. W. , O'GRADY S. , PUSSELL B. A. , CHARLESWORTH J. A.
Published: November 2003

The complement peptide C3a desarg is identical to acylation‐stimulating protein (ASP), a human plasma protein that potently stimulates adipocyte triacylglycerol synthesis and glucose transport. Both human and murine adipocytes express mRNA and/or protein for the complement components C3 and factors B and D (adipsin) required to generate ASP. However, the regulatory mechanisms controlling this process are unknown. We have established a semiquantitative reverse transcriptase polymerase chain reaction (RT‐PCR) technique to demonstrate the presence in mouse 3T3‐L1 adipocytes of mRNA for all components of the alternative pathway, including the control proteins factors I and H, CR1 and properdin. On differentiation, mRNA for C3 (fivefold) and factor D (> 50‐fold) increased, whereas stimulation with tumour necrosis factor (TNF)‐α and interleukin (IL) 1β led to eightfold increases in factor B mRNA. Metabolic labelling followed by immunoprecipitation showed that factor B protein is normally present in small quantities, and is greatly increased by cytokine stimulation. The larger quantities of C3 and H proteins present were little affected, whereas levels of C3a increased on cytokine stimulation. These results suggest that the rate‐limiting step in the cytokine‐induced production of ASP in adipocytes is factor B synthesis.
Specific activation of AP‐1 but not Stat3 in regenerating liver in mice
Authors: HEIM M. H. , GAMBONI G. , BEGLINGER C. , GYR K.
Published: November 2003

Liver regeneration following partial hepatectomy is regulated by hepatotrophic factors whose precise roles are still elusive. In cell culture studies, some of them have been shown to activate members of the family of the signal transducers and activators of transcription (Stat). To test this contention in vivo, nuclear extracts were isolated from livers of partially hepatectomized and sham‐operated mice killed at 30 different time points between zero and 108 h after surgery. Stat3 DNA binding is rapidly induced after surgery in both partially hepatectomized and sham‐operated mice. Maximum activation of Stat3 is achieved 4–6 h after resection, and elevated Stat3 activation is detected as late as 60 h after surgery in both groups. Activated Stat5 is found sporadically in both sham‐operated and resected mice but appears to be absent in the first 12 h after partial hepatectomy. Neither Stat1, Stat2, Stat4 nor Stat6 is induced during the time of observation. In contrast, AP‐1 DNA binding activity is specifically induced in regenerating mouse liver.
Circulating endothelial cell markers in peripheral vascular disease: relationship to the location and extent of atherosclerotic disease
Authors: BLANN A. D. , SEIGNEUR M. , STEINER M. , BOISSEAU M. R. , MCCOLLUM C. N.
Published: November 2003

We examined the relationship between specific endothelial cell markers soluble E‐selectin, von Willebrand factor and soluble thrombomodulin and the location or extent of atherosclerosis by analysing plasma samples from 200 patients with symptomatic peripheral vascular disease and 213 age‐ and sex‐matched asymptomatic control subjects. Using ELISAs, we found increased von Willebrand factor and thrombomodulin (both P < 0.0001) in the patients relative to the control subjects, but no significant change in soluble E‐selectin. Soluble thrombomodulin was increased in patients with disease at one locus (i.e. of the carotid or iliac/femoral arteries), with an additional significant increase in patients with disease at multiple loci (i.e. any combination of carotid, coronary or iliac/femoral artery disease). No marker differentiated carotid artery disease from iliac/femoral artery disease. We conclude that von Willebrand factor is a marker of generalized atherosclerosis, but that soluble thrombomodulin is related to the extent of disease. Further research into these endothelial cell products are warranted to explore their diagnostic and/or prognostic potential.
ATP‐sensitive potassium channels mediate vasodilatation produced by calcitonin gene‐related peptide in human internal mammary but not gastroepiploic arteries
Authors: LUU T. N. , DASHWOOD M. R. , TADJKARIMI S. , CHESTER A. H. , YACOUB M. H.
Published: November 2003

The purpose of this study was to elucidate the mechanism of action of calcitonin gene‐related peptide‐induced vasodilatation of human gastroepiploic and internal mammary arteries. Calcitonin gene‐related peptide (0.1–100 nmol L−1) elicited relaxations of preconstricted vessels, with a significantly greater effect in the gastroepiploic artery (P < 0.05). This effect was independent of endothelium‐derived vasodilating substances. The response of the internal mammary artery but not the gastroepiploic artery to calcitonin gene‐related peptide was attenuated by glybenclamide (1.0 μmol L−1) (P < 0.05). In vitro autoradiography indicated that [125I]‐calcitonin gene‐related peptide bound to the tunica media but not the endothelial cells in both types of artery, with a significantly higher degree of binding in the gastroepiploic artery. It is concluded that calcitonin gene‐related peptide acts directly on vascular smooth muscle via specific binding sites to induce vasodilatation. In addition, KATP channels are involved in the action of calcitonin gene‐related peptide in the internal mammary artery but not in the gastroepiploic artery.
Cascading predation effects of Daphnia and copepods on microbial food web components
Authors: Zöllner Eckart , Santer Barbara , Boersma Maarten , Hoppe Hans‐Georg , Jürgens Klaus
Published: November 2003

1. We performed a mesocosm experiment to investigate the structuring and cascading effects of two predominant crustacean mesozooplankton groups on microbial food web components. The natural summer plankton community of a mesotrophic lake was exposed to density gradients of Daphnia and copepods. Regression analysis was used to reveal top–down impacts of mesozooplankton on protists and bacteria after days 9 and 15.

2. Selective grazing by copepods caused a clear trophic cascade via ciliates to nanoplankton. Medium‐sized (20–40 μm) ciliates (mainly Oligotrichida) were particularly negatively affected by copepods whereas nanociliates (mainly Prostomatida) became more abundant. Phototrophic and heterotrophic nanoflagellates increased significantly with increasing copepod biomass, which we interpret as an indirect response to reduced grazing pressure from the medium‐sized ciliates.

3. In Daphnia‐treatments, ciliates of all size classes as well as nanoflagellates were reduced directly but the overall predation effect became most strongly visible after 15 days at higher Daphnia biomass.

4. The response of bacterioplankton involved only modest changes in bacterial biomass and cell‐size distribution along the zooplankton gradients. Increasing zooplankton biomass resulted either in a reduction (with Daphnia) or in an increase (with copepods) of bacterial biovolume, activity and production. Patterns of bacterial diversity, as measured by polymerase chain reaction–denaturing gradient gel electrophoresis (PCR–DGGE), showed no distinct grouping after 9 days, whereas a clear treatment‐coupled similarity clustering occurred after 15 days.

5. The experiment demonstrated that zooplankton‐mediated predatory interactions cascade down to the bacterial level, but also revealed that changes occurred rather slowly in this summer plankton community and were most pronounced with respect to bacterial activity and composition.
The distribution and location of the symbiontLagenophrys asellion the freshwater isopodAsellus aquaticus
Authors: Roberts G. N. , Chubb J. C.
Published: November 2003

1. The distribution and location of the ciliated protozoan Lagenophrys aselli on the freshwater isopod Asellus aquaticus were studied in relation to water flow over the third pleopod surface.

2. At low densities L. aselli had a significant preference for the anterior centre of the pleopod; however, at the highest densities this preference was no longer significant. The distribution ranged from closer than random at low densities to further than random at the highest densities, and may have been a product of feeding and reproduction of L. aselli as well as the short intermoult period of the host.

3. An individual L. aselli has an effective area of both the lorica and the ciliated feeding disc. The ciliated feeding disc, when extended, may contribute to the presence of a small anterior–posterior gap being left between individuals.
Genetic structure in a montane mayfly Baetis bicaudatus (Ephemeroptera: Baetidae), from the Rocky Mountains, Colorado
Authors: Hughes Jane M. , Mather Peter B. , Hillyer Mia J. , Cleary Cath , Peckarsky Barbara
Published: November 2003

1. Populations of a number of sub‐tropical stream insect species have been found to show unexpected patterns of genetic variation, with more differences between samples from the same stream than between whole streams or between subcatchments. Many samples also showed deviations from Hardy–Weinberg proportions. It has been proposed that these patterns result from limited numbers of matings contributing to a given stream reach, because adults emerge throughout the year, and low levels of larval drift between reaches. These patterns may be less likely in a northern hemisphere montane species with synchronous emergence of adults and high levels of drift. We tested the hypothesis that patterns of genetic variation in a montane mayfly from the Rocky Mountains, Colorado, would reflect a pattern of ‘isolation by distance’ with samples from the same creek being more similar than samples from different creeks and that deviations from Hardy–Weinberg proportions would be minimal.

2. Based on allozyme variation, the hypothesis of minimal deviations from Hardy–Weinberg proportions was not supported and there was no evidence of isolation by distance. Nevertheless the levels of differentiation among samples from within the same stream were less than those reported for most subtropical species.

3. Results from analysis of a fragment of the cytochrome oxidase gene (subunit 1) revealed contrasting patterns. The levels of genetic differentiation were an order of magnitude higher between streams than among samples within streams. In addition, although there was no significant isolation by distance effect overall, a nested clade analysis provided evidence for restricted gene flow with isolation by distance for some clades.

4. We suggest that these contrasting results may reflect the differences in male and female dispersal patterns. While differentiation at nuclear gene markers (allozymes) give information about both male and female dispersal, mitochondrial DNA markers reflect only female dispersal. We suggest that in this species, female dispersal may be more restricted, perhaps mostly along stream channels, whereas male dispersal is more widespread. An alternative explanation for the different results is the different evolutionary rates of the mitochondrial and nuclear markers.
Timing of spawning and glochidial release in Scottish freshwater pearl mussel (Margaritifera margaritifera) populations
Authors: Hastie Lee C. , Young Mark R.
Published: November 2003

1. The timing of reproduction was investigated in six Scottish freshwater pearl mussel populations from 1993 to 2002. Gravid females were examined and the release of mussel larvae (glochidia) was monitored.

2. Annual spawning (oviposition) and spat (glochidial release) events occurred during June to July and June to September, respectively.

3. Between‐river differences in timing seem to be related to water temperature. Mussels in the warmest rivers tend to spawn and spat first, and vice‐versa.

4. Thermal variations also seem to influence the timing of reproduction within rivers, which can be delayed by several weeks during cold years. At least 3000°‐days occur between annual episodes of glochidial release.

5. The timing of spawning is determined gradually, probably by a thermal summation effect.

6. The release stage occurs as a sudden, synchronised event, with most of the glochidia spat over 1–2 days, indicating that it is triggered by an environmental cue. Sudden changes in water temperature and/or river level often result in spats, and the underlying mechanism may be respiratory.
Biomanipulation: a useful tool for freshwater wetland mitigation?
Authors: Angeler David G. , Chow‐Fraser Patricia , Hanson Mark A. , Sánchez‐Carrillo Salvador , Zimmer Kyle D.
Published: November 2003

1. Natural wetlands have traditionally been considered as efficient ‘ecological engineers’ for waste water treatment. However, the structure and function of many natural wetlands have been severely altered by the chronic exposure to pollutants, especially nutrients.

2. Despite the similarity of symptoms of eutrophied shallow lakes and wetlands, restoration strategies differ distinctly between these rather similar aquatic systems. Many of the tools applied in shallow lake restoration programs, for example biomanipulation, have received little attention in wetland management and restoration.

3. Although a strong conceptual basis for food web management exists, biotic interactions as influences on wetland communities have been largely neglected by wetland scientists and managers.

4. In this paper we show that biomanipulation may have a strong potential for wetland eutrophication abatement. This potential will be demonstrated by reviewing studies carried out in different wetland types in contrasting climatic regions.

5. We propose four different scenarios for when, where and why biomanipulation may be used to rehabilitate freshwater wetlands. These scenarios reflect different settings of hydrological variability, eutrophication sources and gradients of wind exposure and water colour.
Effects of the angiotensin AT1 receptor antagonist GR138950 on haemodynamic function in dogs
Authors: Hunt A. A. E. , Hilditch A. , Drew G. M.
Published: November 2003

1 The antagonist activity of the angiotensin AT1 receptor antagonist, GR138950, and its haemodynamic effects have been investigated in beagle dogs.

2 In four anaesthetized dogs, GR138950 (0.1, 1 and 10 mg kg–1 i.v.), displaced dose–response curves to angiotensin II (AngII) rightwards, in a parallel manner; GR138950, at 1 mg kg–1 i.v., produced a 15‐fold displacement of the AngII dose–response curve. In four conscious dogs, GR138950 (1 mg kg–1 i.v. or p.o.) antagonized AngII, and produced rightward and parallel displacements of the AngII dose–pressor response curves. Maximum displacements of approximately 33‐ and 16‐fold occurred at 1 h after intravenous and 5 h after oral administration, respectively. The inhibitory effect of GR138950 was long lasting; AngII dose–pressor response curves were still displaced by 10‐fold from control values, 24 h after intravenous or oral administration of GR138950.

3 In comparison with its vehicle, GR138950 (0.1–10 mg kg–1) caused a significant decrease in resting blood pressure as a consequence of a significant decrease in total peripheral resistance in anaesthetized dogs. Effects on cardiac output, stroke volume and heart rate were not significantly different between GR138950‐ or vehicle‐treated dogs.

4 Compared with vehicle, GR138950 administration did not significantly affect blood flow to the mesenteric and femoral vascular beds but did significantly increase blood flow to the renal vascular bed. Vascular resistance of the femoral bed was unaffected but that of the mesenteric and renal vascular beds was significantly reduced by GR138950, compared with the changes produced by vehicle treatment.

5 Compared with vehicle, left ventricular end diastolic pressure was significantly reduced by GR138950, but GR138950 had no significant effect on indices of cardiac contractility (+dP/dtmax and +dP/dt@40) or cardiac relaxation during early diastole (‐dP/dt).

6 In conclusion, GR138950 acts as a competitive, surmountable antagonist at vascular angiotensin II receptors in beagle dogs. GR138950 reduced arterial blood pressure by reducing total peripheral resistance, attributable partly to reduction in resistance in the mesenteric and renal vascular beds. GR138950 reduced left ventricular end diastolic pressure whilst having no direct effect on cardiac contractility or relaxation.
Inhibition of vasodilator neurotransmission in the sheep middle cerebral artery by VIP antiserum
Authors: Matthew J. D. , Wadsworth R. M. , McPhaden A. R.
Published: November 2003

1 Middle cerebral artery rings from the sheep were relaxed by vasoactive intestinal peptide (VIP) (20–200 nM) or by stimulation of the vasodilator nerves, electrical field stimulation (EFS).

2 VIP antiserum 1:256 inhibited the relaxation produced by both exogenous VIP (from 70 ± 5 to 32 ± 9% of 5‐HT‐induced tone at 200 nM VIP) and by EFS (from 43 ± 5 to 26 ± 6% of 5‐HT‐induced tone after 20 min), while pre‐immune serum was inactive.

3 Capsaicin (1 μm) produced a transient relaxation but did not alter the response to EFS which was subsequently inhibited by addition of L‐NOArg (100 μM). VIP‐induced relaxation was antagonized by L‐NOArg (50 μM) (from 68 ± 5 to 46 ± 2% relaxation of 5‐HT‐induced tone) but not by D‐NOArg.

4 Exogenous VIP produced an approximately 2.4‐fold increase in cyclic GMP content which was prevented by preincubation with L‐NOArg (100 μM) but not D‐NOArg.

5 VIP and neuronal NOS immunoreactivity was co‐localized to the same adventitial nerve fibres in the sheep middle cerebral artery.

6 These results provide evidence that neurogenic relaxation in the sheep middle cerebral artery is, at least in part, mediated by VIP, involving activation of NO synthase.
Suppression of the rat micturition reflex by imipramine
Authors: Sohn U. D. , Kim C. Y.
Published: November 2003

1 This study investigates possible mechanisms through which imipramine (IMI) exerts its antienuretic effect. The micturition reflex in response to bladder distension produced by saline infusion was examined in anaesthetized rats.

2 The amplitude and frequency of micturition reflex contractions were reduced by peripheral administration of IMI, but the micturition reflex was abolished after its intracerebroventricular (i.c.v.) administration. A muscarinic antagonist, atropine, displayed an inhibitory effect similar to that of IMI. A muscarinic agonist, carbachol, produced a dose‐related rightward shift of the dose–response curve to IMI. Both IMI i.c.v. and the muscarinic antagonist l‐methylscopolamine i.c.v. elevated the threshold of volume and pressure for micturition initiation, indicating that IMI and muscarinic antagonists mainly exert a central inhibitory effect on the micturition reflex.

3 In addition, to evaluate the role of central monoaminergic neurotransmission on micturition, the acetylcholine depletor hemicholinium‐3 (HC‐3), the catecholamines depletor α‐methyl‐p‐tyrosine (AMPT), and the serotonin depletor p‐chlorophenylalanine (PCPA) were examined alone or in combination with IMI. The micturition threshold was increased by treatment with HC‐3, but not by AMPT or PCPA. In HC‐3 treated rats, the inhibitory effect of IMI on the micturition reflex was more prolonged than in normal rats. After administration of IMI, the recovery from the cessation of micturition reflex contractions was facilitated by carbachol in normal rats, but not in HC‐3 treated rats. This indicates that acetylcholine plays a facilitatory role in initiating micturition reflex contractions.

4 Acute treatment with IMI decreased the frequency and increased the volume threshold of micturition reflex contraction. Acute and chronic treatment with IMI prolonged the cessation period of micturition by IMI.

5 These results suggest that IMI exerts an inhibitory action on the micturition reflex by a central cholinergic mechanism. Muscarinic receptors located at the supraspinal level are tonically stimulated during distension‐induced micturition reflex.
Effect of 4‐aminopyridine and 3,4‐diaminopyridine on guinea‐pig isolated ileum
Authors: Velasco A. , Maroto M. , Dueñas A. , Carvajal A. , Fernández de la Gándara F. , Nieto A.
Published: November 2003

1 4‐Aminopyridine and 3,4‐diaminopyridine produced concentration‐dependent contraction on guinea‐pig isolated ileum incubated in Tyrode solution. The EC50 values were 1.14 × 10−4 and 1.39 × 10−4M, respectively.

2 Calcium channel blockers such as verapamil, diltiazem, nifedipine, flunarizine, and lanthanum chloride antagonized the contracting effect induced by 4‐aminopyridine and 3,4‐diaminopyridine in guinea‐pig isolated ileum.

3 Diazoxide and atropine sulphate behaved similarly as antagonists of the contracting effect induced by 4‐aminopyridine and 3,4‐diaminopyridine in guinea‐pig isolated ileum.

4 It is concluded that the aminopyridines exert their effects through the release of acetylcholine from parasympathetic nerve terminals.
On evidence, embellishment and efficacy
Authors: Morgan W. K. C.
Published: November 2003

Evidence‐based medicine (EBM) — to use a vogue word — is the contemporary mantra of many academic physicians. Unfortunately, the evidence they consider, although superficially convincing, is often slanted, occasionally deliberately, but more often as a result of carelessness and defects in study design. These biases and confounding factors are often hidden and arcane and seriously impair objective assessment. Such defects can only be detected when all investigators agree to go along with Bradford Hill's dictum, namely ‘It is the essence of science to disclose both the data upon which a conclusion is based and the methods by which the conclusion is obtained’; a cardinal rule more often honoured in the breach than the observance.
Quantitative assessment of serum hepatitis B e antigen, IgM hepatitis B core antibody and HBV DNA in monitoring the response to treatment in patients with chronic hepatitis B
Authors: Bernard F. , Raymond G. , Willems B. , Villeneuve J.‐P.
Published: November 2003

Summary. Virological response to treatment of chronic hepatitis B is defined as the loss of serum hepatitis B virus DNA (HBV DNA) and hepatitis B e antigen (HBeAg). The quantitative measurement of HBV DNA is useful for monitoring and predicting the response to therapy with interferon‐α (IFN‐α). In this study, we evaluated whether quantitative measurement of serum HBeAg and IgM antibody to hepatitis B core antigen (HBcAb) could also be used in this manner. Using a microparticle‐capture enzyme immunoassay (IMx), a standard curve of fluorescence rate vs HBeAg concentration was constructed to provide quantitative results. The IgM HBcAb index was also measured using a microparticle enzyme immunoassay and serum HBV DNA was measured by a solution hybridization assay. We studied 48 patients who were initially positive for HBeAg and HBV DNA and who were treated with IFN‐α2b. Their sera were serially evaluated for HBeAg concentration, and results were compared with HBV DNA levels. In the 14 patients who responded to IFN, similar disappearance curves were observed with good intrain‐dividual correlation between the levels of the two markers. In the 34 non‐responders. HBeAg levels decreased during treatment but never became negative; HBV DNA levels also decreased during treatment and became transiently undetectable in six patients, falsely suggesting treatment success. The IgM HBcAb index paralleled changes in alanine aminotransferase (ALT) concentration and did not provide additional information. Multiple logistic regression indicated that baseline ALT and HBeAg concentrations were independent predictors of the response to treatment and the addition of neither HBV DNA nor IgM HBcAb improved the model. We conclude that quantitative measurement of HBeAg provides information similar to that of HBV DNA in monitoring and predicting the response to treatment; this technique could be readily adaptable to clinical laboratories.
Preoperative serum levels of wild‐type and hepatitis B e antigen‐negative hepatitis B virus (HBV) and graft infection after liver transplantation for HBV‐related hepatocellular carcinoma
Authors: Mazzaferro V. , Brunetto M. R. , Pasquali M. , Regalia E. , Pulvirenti A. , Baratti D. , Makowka L. , van Thiel D. , Bonino F.
Published: November 2003

Summary.Allograft infection in hepatitis B surface antigen (HBsAg)‐positive patients undergoing liver transplant (OLT) is still significant, despite post‐transplant prophylaxis with high doses of immunoglobulin to HBsAg. Baseline status and post‐OLT levels of viraemia and wild‐type and hepatitis B e antigen (HBeAg)‐negative hepatitis B virus (HBV) were correlated with the clinical course of 16 consecutive HBsAg carriers, positive for hepatitis B e antibody, with hepatocellular carcinoma who underwent OLT and received permanent post‐OLT prophylaxis with antibody to HBsAg (HBsAb). Fourteen patients had less than 103HBV genome equivalents ml‐1(eqml‐1) at baseline and remained HBV free after a median of 36 months following OLT. Two patients with mean pre‐OLT viraemia higher than 105genome eq ml‐1and prevalent HBeAg‐negative HBV viraemia before OLT suffered a severe graft hepatitis. Interferon‐α2b (3 MU m‐2per day) was able to reduce viraemia in both patients and to revert the clinical course of the infection in one, who remained infection‐free 22 months after IFN treatment. Fourteen patients had less than 103HBV genome eq ml‐1at baseline and remained HBV free, after a median of 36 months following OLT, with permanent HBsAb immunoprophylaxis. These observations suggest that the quantitative analysis of HBV pre‐OLT viraemia levels may provide a very useful tool for predicting the ideal time of liver replacement. Clinical trials on the use of antiviral drugs capable of inhibiting HBV serum levels before liver transplantation should be pursued on this premise.
Exposure to hepatitis A virus among blood donors, injecting drug users and prison entrants in Victoria
Authors: Crofts N. , Cooper G. , Stewart T. , Kiely P. , Coghlan P. , Hearne P. , Hocking J.
Published: November 2003

Summary. To assess prevalence of exposure to hepatitis A virus (HAV) among injecting drug users (IDUs) and prison entrants in Victoria, and to compare this with prevalence of HAV among a reference population of blood donors, sera stored from two previous studies and from randomly selected blood donors were tested for total antibody to HAV. The first study was a longitudinal study of field‐recruited EDUs from 1990 to 1992 and the second was a study of all prison entrants in 1991‐92 (both studies were carried out in Victoria); blood donors were from the Australian Red Cross Blood Bank Victoria in 1995. Forty five per cent of 2175 prison entrants and 51% of 293 IDUs were seropositive for HAV, compared with 30% of 2995 blood donors. When standardized for age against the blood donors, HAV seropositivity in IDUs was 44% and in prison entrants 60%. The strongest association of HAV seropositivity among the EDUs on multivariate analysis was a history of imprisonment. There are high rates of exposure to HAV among prison entrants, whether with a history of EDU or not, and among IDUs who have a prison history. The role of sharing contaminated injecting equipment in transmission of HAV seems to be less important than institutionalization per se. With adequate resourcing, both populations are appropriate targets for HAV vaccination, especially in a context of continuing decline of transmission of HAV in the general community.
Hepatitis B virus genomic heterogeneity: variation between quasispecies may confound molecular epidemiological analyses of transmission incidents
Authors: Ngui S. L. , Teo C. G.
Published: November 2003

Summary.Nucleotide sequence variability studies were conducted on a 263‐base pair fragment of the core‐coding genomic region of hepatitis B virus (HBV), amplified by the polymerase chain reaction (PCR) from three surgeons with varying circulating levels of HBV, all of whom were thought to have transmitted HBV to their patients post‐surgically. DNA sequencing was applied to amplicons obtained directly from serum and those cloned into plasmid vectors, and from single HBV molecules in serum separated by a limiting dilution procedure. In one surgeon, who had a titre of ˜ 3 × 105genome equivalents ml‐1, the direct sequence was identical to none of 29 other sequences and differed by one base substitution from the sequence amplified from the single patient he infected. In another surgeon, who had a titre of ˜ 2 × 106genome equivalents ml‐1, the direct sequence was identical to 17 of 36 (47%) sequences; however, the sequence common to all three infected patients was identical to a unique sequence in the surgeon that differed by three base substitutions from the direct sequence. By contrast, the direct sequence in the third surgeon, who had a titre of ˜ 4 × 107genome equivalents ml‐1, was identical to 25 of 38 (66%) sequences, and to the sequence common to all 11 infected patients. Assessment of HBV DNA sequences directly amplified from clinical specimens may not be appropriate to studies of transmission in which the source of infection harbours a relatively dilute, heterogenous mix of viral variants.
Severe hepatitis E infection during pregnancy
Authors: Hussaini S. H. , Skidmore S. J. , Richardson P. , Sherratt L. M. , Cooper B. T. , O’Grady J. G.
Published: November 2003

In areas with endemic hepatitis E virus (HEV), acute liver failure secondary to hepatitis E infection is common in pregnancy and associated with a mortality rate of up to 20%. However, there is little information on the clinical course of severe hepatitis E infection during pregnancy in non‐endemic areas such as the UK. Here we describe two cases of severe hepatitis E in pregnancy in patients returning from the Indian subcontinent. These cases were diagnosed by the detection of IgM anti‐HEV antibody using an enzyme immunoassay with recombinant hepatitis E viral antigens. The first case describes acute hepatic failure, with coagulopathy and encephalopathy, warranting intensive therapy and elective ventilation. In the other case, the patient had severe hepatitis with coagulopathy. Both cases spontaneously resolved with no foetal loss. These cases highlight the need for suspicion of HEV infection in patients returning from endemic areas and presenting with acute non‐A non‐B hepatitis, especially when pregnant. Furthermore, the intensive treatment of acute liver failure caused by HEV may reduce the high mortality reported in Asia.
Transforming growth factor‐ß1 in chronic hepatitis C
Authors: Nelson D. R. , Gonzalez‐Peralta R. P. , Qian K. , Xu Y. , Marousis C. G. , Davis G. L. , Lau J. Y. N.
Published: November 2003

Transforming growth factor‐ß1 (TGF‐ß1) has been implicated in mediating hepatic fibrogenesis and is known to have negative regulatory effects on the immune system. To analyse the effects of TGF‐ß1 in chronic HCV, serum samples were prospectively collected from 88 chronic hepatitis C virus (HCV) patients and 34 healthy controls. Total and biologically active TGF‐ß1, interleukin (IL)‐4 and IL‐10 were measured by enzyme‐linked immunosorbent assay (ELISA). HCV RNA levels were quantified by branched DNA signal amplification pathway (bDNA), and HCV genotypes were determined by restriction fragment length polymorphism (RFLP) based on the 5'‐untranslated region (UTR). Histological diagnosis was available in 87 patients, and liver sections from 80 other HCV patients were evaluated for hepatic expression of TGF‐ß1 using immunohistochemistry. Patients with chronic HCV infection had a higher level of TGF‐ß1, both total (817±464ngml–1) and biologically active forms (520±370pgml–1), compared with controls (total TGF‐ß1 183±105ngml–1, P<0.001; active TGF‐ß1 290±140pgml–1, P<0.01). There was no correlation between either total or biologically active TGF‐ß1 and clinical variables (age, gender, duration), liver biochemistry (serum alanine aminotransferase) or virological (HCV RNA level, genotype) parameters but there was a correlation between total TGF‐ß1 and Knodell scores (P=0.03, n=54). However, when individual histological parameters were analysed, only the fibrosis score showed significant correlation (P=0.04, n=54). Immunohistochemistry revealed that 62% of HCV patients had TGF‐ß1 present in sinusoidal cells. No correlation existed between hepatic expression of TGF‐ß1 and any histological parameters. A trend existed towards a correlation between total TGF‐ß1 and IL‐4 (P=0.059, n=74) but not with IL‐10. Therefore, the TGF‐ß1 system is activated in chronic HCV infection and may contribute towards hepatic fibrogenesis; in addition, the TGF‐ß1 system may interact with IL‐4.
Comparison of the Chiron Quantiplex branched DNA (bDNA) assay and the Abbott Genostics solution hybridization assay for quantification of hepatitis B viral DNA
Authors: Kapke G. F. , Watson G. , Sheffler S. , Hunt D. , Frederick C.
Published: November 2003

Several assays for quantification of DNA have been developed and are currently used in research and clinical laboratories. However, comparison of assay results has been difficult owing to the use of different standards and units of measurement as well as differences between assays in dynamic range and quantification limits. Although a few studies have compared results generated by different assays, there has been no consensus on conversion factors and thorough analysis has been precluded by small sample size and limited dynamic range studied. In this study, we have compared the Chiron branched DNA (bDNA) and Abbott liquid hybridization assays for quantification of hepatitis B virus (HBV) DNA in clinical specimens and have derived conversion factors to facilitate comparison of assay results. Additivity and variance stabilizing (AVAS) regression, a form of non‐linear regression analysis, was performed on assay results for specimens from HBV clinical trials. Our results show that there is a strong linear relationship (R2 = 0.96) between log Chiron and log Abbott assay results. Conversion factors derived from regression analyses were found to be non‐constant and ranged from 6–40. Analysis of paired assay results below and above each assay’s limit of quantification (LOQ) indicated that a significantly (P < 0.01) larger proportion of observations were below the Abbott assay LOQ but above the Chiron assay LOQ, indicating that the Chiron assay is significantly more sensitive than the Abbott assay. Testing of replicate specimens showed that the Chiron assay consistently yielded lower per cent coefficients of variance (% CVs) than the Abbott assay, indicating that the Chiron assay provides superior precision.
Hepatitis G virus infection: clinical characteristics and response to interferon
Authors: Karayiannis P. , Hadziyannis S. J. , Kim J. , Pickering J. M. , Piatak M. , Hess G. , Yun A. , McGarvey M. J. , Wages J. , Thomas H. C.
Published: November 2003

A new member of the Flaviviridae family has recently been cloned and completely sequenced. The new virus, tentatively named hepatitis G virus (HGV) and known to be closely related to GB virus C (GBV‐C), is transmitted by blood and blood products, intravenous drug use and other behaviour associated with a high risk of parenteral exposure to blood. The association of the virus with hepatitis is demonstrated by the presence of raised liver transaminase (alanine aminotransferase, ALT) levels in patients infected with HGV in the absence of other identifiable causes of hepatitis. No patient sera from groups exposed to blood and blood products were found to be positive when tested for the presence of GBV‐A or GBV‐B sequences, two other recently described flaviviruses. Forty‐five per cent of the HGV‐infected patients investigated had normal ALT suggesting the existence of a normal carrier state. Persistent infection of up to 13 years duration was observed. Co‐infection with hepatitis B or hepatitis C viruses (HBV and HCV) was commonly seen presumably because of shared risk factors. None of five patients with fulminant hepatic failure was positive for HGV infection. The virus is sensitive to interferon‐α, but sustained responses were not seen with the treatment regimens used for HBV and HCV. Viral titres increased during immunosuppression following liver transplantation and the higher levels of viraemia were in one case accompanied by elavated ALT. Whether HGV (GBV‐C) replicates in the liver in some or all cases remains to be established. Preliminary data suggest that it is present within peripheral blood lymphocytes.
Ribavirin and interferon‐α combination therapy vs interferon‐α alone in the retreatment of chronic hepatitis C: a randomized clinical trial
Authors: Bellobuono A. , Mondazzi L. , Tempini S. , Silini E. , Vicari F. , Idéo G.
Published: November 2003

Summary. Interferon‐aL (IFN‐α) induces sustained remission of chronic hepatitis C in approximately 25% of patients. In patients who are non‐responders to the first course of therapy, retreatment with IFN‐α is of limited efficacy. Ribavirin has also been used to treat chronic hepatitis C, but it induces only a transient response. In this study, we evaluated the efficacy of ribavirin and IFN‐α combination therapy for IFN‐α resistant chronic hepatitis C. Twenty‐four IFN‐α non‐responders and 24 relapsers were randomized to receive either ribavirin (1000 mg per day) together with IFN‐α (3–6 million units (MU) thrice weekly) or the same dose of IFN‐α alone, for 6 months. Both at the end of treatment and 6 months later, normal transaminase levels were more common in the patients receiving combination therapy than in the group receiving IFN‐α alone: 17 (70.8%) vs seven (29.2%) patients (P= 0.009) and six (25%) vs one (4.2%) patient (P= 0.034), respectively. At the end of treatment and 6 months later, serum HCV RNA was no longer detectable in eight (33.3%) and five (20.8%) patients in the combination therapy group and in six (25%) and one (4.2%) patient in the IFN‐α therapy group, respectively. Three patients (12.5%) were withdrawn prematurely from combination therapy because of side‐effects; ribavirin therapy was ceased or dosage reduced in six other patients (25%), again because of side‐effects. In conclusion, this combination treatment was more effective than retreatment with IFN‐α, alone, in inducing sustained biochemical remission of chronic hepatitis C that was resistant to a previous course of IFN‐α. The combination treatment, however, was frequently associated with significant side‐effects.