bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of hypertonic saline dextran in trauma resuscitation
Authors: Perera AM , Porter KM
Published: May 2003

Modern trauma management has recognized the importance of using conservative fluid resuscitation regimes in order to prevent complications from fluid overload arising. Hypertonic/hyperoncotic fluids appear to provide an ideal means of facilitating this, requiring only small volumes to rapidly elevate blood pressure. Hypertonic saline dextran (HSD) was introduced in 1985 but its take up has been slow, a large part of this has been due to the lack of human trials and concerns about complications.

The current evidence has been reviewed and it is clear that HSD is an efficient means of correcting hypotension, doing so mainly by the mobilizing endogenous water. It is becoming apparent that early administration has the potential to modulate the inflammatory cascade in patients at risk of developing adult respiratory distress syndrome (ARDS) and multiorgan failure. This is reflected in the handful of human trials that show a trend towards increased survival (particularly for head injuries) and a possible reduction in ARDS. The side effect profile appears to be good, even in the presence of dehydration or penetrating trauma.

Published human trials have methodological problems and lack of power of study this has led to a reliance on animal studies. Clearly there is great potential, but before large-scale prehospital usage can be justified further well-conducted randomized human trials are needed.
Traumatic soft tissue injuries of the shoulder girdle
Authors: Levy Ofer , Rath Ehud
Published: May 2003

As the major hinge of motion of the upper extremity, the shoulder girdle is prone to soft tissue injuries associated with trauma or overuse. Most soft tissue injuries are tendon injuries, joint sprains or dislocations. The trauma mechanism, position of the arm, the anatomic location of pain and presence of referred pain should be investigated. A detailed history and careful physical examination will lead to the diagnosis of specific disorders in most cases. A wide selection of imaging studies is available for shoulder problems. The imaging of choice should be chosen based on the working diagnosis and cost. This review focuses on the diagnosis and management of acute and chronic soft tissue injuries and pathologies involving the adult shoulder.
Recent advances in topical agents for prehospital haemostasis
Authors: Garner JP , Brown RFR
Published: May 2003

The prehospital treatment of severe extremity bleeding has remained unchanged for years and relies on compression with absorbent gauze dressings. Advances in haemostasis technology have identified several new methods of improving bleeding control. These are examined with a view to possible inclusion in a new prehospital dressing aimed at reducing the degree of exsanguination and associated mortality and morbidity from a major extremity injury.
Challenges in recruitment of research participants
Authors: Patel Maxine X. , Doku Victor , Tennakoon Lakshika
Published: May 2003

There are many potential pitfalls in the identification and enlistment of suitable candidates for psychiatric research. The challenges of recruitment are highlighted, detailing impact of study design, characteristics of participants, including demographics and personal preferences, investigator characteristics and collaboration with clinicians. Techniques used in recruitment are discussed, including financial incentives, assertive tracking and communication methods. Ethical issues, methods of data collection, and control participants are also considered. Key issues are: early consideration of the impact of study design on the recruitment process; the participant's perspective; close collaboration with colleagues; the investigator's good interpersonal, communication and organisational skills; and feedback to collaborators, associated clinicians and participants.
IGDA. 3: use of extended sources of information
Authors:   IGDA Workgroup, WPA
Published: May 2003

The use of extended sources of information is an important part of the diagnostic process, since they corroborate, complement or correct information provided by the patients themselves.
IGDA. 7: Standardised multi-axial diagnostic formulation
Authors:   IGDA Workgroup, WPA
Published: May 2003

A thorough and systematic assessment of a patient should lead to a comprehensive diagnostic statement. The first component of this is the multi-axial diagnostic formulation.
IGDA. 11: Illustrative clinical case
Authors:   IGDA Workgroup, WPA
Published: May 2003

Ms Y is a 28-year-old monolingual Spanish-speaking woman of Mexican origin living for 2 years in the USA and married to a Mexican man self-employed in the construction business. She presents for care to the emergency room accompanied by a female friend, complaining of ‘nervios’, feeling guilty for not being able to perform her duties as a wife, and concerned that there may be some type of imbalance in her body. The interviewer is a female psychiatrist, born in South America and trained in the USA.
Structural disconnectivity in schizophrenia: a diffusion tensor magnetic resonance imaging study
Authors: Burns J. , Job D. , Bastin M. E. , Whalley H. , Macgillivray T. , Johnstone E. C. , Lawrie S M.
Published: May 2003

Background

There is growing evidence that schizophrenia is a disorder of cortical connectivity Specifically, frontotemporal and frontoparietal connections are thought to be functionally impaired. Diffusion tensor magnetic resonance imaging (DT–MRI) is a technique that has the potential to demonstrate structural disconnectivity in schizophrenia.

Aims

To investigate the structural integrity of frontotemporal and frontoparietal white matter tracts in schizophrenia.

Method

Thirty patients with DSM–IV schizophrenia and thirty matched control subjects underwent DT–MRI and structural MRI. Fractional anisotropy – an index of the integrity of white matter tracts – was determined in the uncinate fasciculus, the anterior cingulum and the arcuate fasciculus and analysed using voxel-based morphometry.

Results

There was reduced fractional anisotropy in the left uncinate fasciculus and left arcuate fasciculus in patients with schizophrenia compared with controls.

Conclusions

The findings of reduced white matter tract integrity in the left uncinate fasciculus and left arcuate fasciculus suggest that there is frontotemporal and frontoparietal structural disconnectivity in schizophrenia.
Mild cognitive impairment: prevalence and incidence according to different diagnostic criteria
Authors: Busse Anja , Bischkopf Jeannette , Riedel-Heller Steffi G. , Angermeyer Matthias C.
Published: May 2003

Background

Although mild cognitive impairment is associated with an increased risk of developing dementia, there has been little work on its incidence and prevalence.

Aims

To report age-specific prevalence, incidence and predictive validities for four diagnostic concepts of mild cognitive impairment.

Method

A community sample of 1045 dementia-free individuals aged 75 years and over was examined by neuropsychological testing in a three-wave longitudinal study.

Results

Prevalence rates ranged from 3% to 20%, depending on the concept applied. The annual incidence rates applying different case definitions varied from 8 to 77 per 1000 person-years. Rates of conversion to dementia over 2.6 years ranged from 23% to 47%.

Conclusions

Mild cognitive impairment is frequent in older people. Prevalence, incidence and predictive validities are highly dependent on the diagnostic criteria applied.
A survey of methadone prescribing at an inner-city drug service and a comparison with national data
Authors: Dunn John
Published: May 2003

Aims and Method

Surveys suggest that UK drug services under-prescribe methadone to opiate-dependent patients. This study investigated methadone prescribing for 169 patients on long-term methadone at a specialist drug service.

Results

The mean methadone dose for patients on maintenance was 65.8 mg, and 67.7% were taking 50 mg or more. Mean doses in relation to methadone formulation varied substantially: mixture 57.4 mg, tablets 81.8 mg and ampoules 113.0 mg. These figures are higher than those reported from national surveys. The proportion of urine screens positive for illicit opiates was inversely related both to methadone dose and length of time in treatment.

Clinical Implications

This survey shows the levels of methadone prescribing at an inner-city drug service and gives support to the effectiveness of high-dose methadone maintenance.
Implementation of the Care Programme Approach in prison
Authors: Pyszora Natalie M , Telfer Julia
Published: May 2003

Aims and Method

Recent government legislation has highlighted the importance of implementation of the Care Programme Approach (CPA) within prisons, as part of the expectation that prisoners receive equivalent standards of healthcare to those provided by the National Health Service. To effectively plan the service provision at HMP Belmarsh, we retrospectively established the number of prisoners in a one-year period who would have fulfilled the criteria for enhanced CPA.

Results

Of the 91 prisoners found to fulfil the criteria for enhanced CPA, the majority (77%) had a diagnosis of schizophrenia, schizoaffective or delusional disorder, and 58% required transfer to a psychiatric hospital. Of those who required hospital treatment, 75% needed conditions of high- or medium-security.

Clinical Implications

Successful implementation of the CPA for all prisoners who meet enhanced CPA criteria is likely to have significant resource implications, both for mental health teams working within prisons and local psychiatric services.
Service innovations
Authors: Graham Hermine L. , Copello Alex , Birchwood Max , Orford Jim , McGovern Dermot , Georgiou George , Godfrey Emma
Published: May 2003

One of the challenges for services in the UK has been how best to meet the needs of those people who experience severe mental health problems and use drugs and alcohol problematically. It is now well-documented in the international literature that the coexistence of severe mental health and substance misuse problems are common (e.g. Regier et al, 1990; Krausz et al, 1996; Menezes et al, 1996; Fowler et al, 1998; Mueser et al, 2000; Graham et al, 2001) and often correlated with a number of adverse outcomes (Smith & Hucker, 1994; Johnson, 1997; Mueser et al, 2000). Integrated treatment approaches developed in the USA for this client group (e.g. Drake & Wallach, 2000; Drake et al, 2001), and although they offer much food for thought and some direction, they could not be wholly imported and implemented in the UK because of significant differences in the contextual factors that guide service provision in the two countries. The challenge in the UK has been to develop effective services that fit with the unique community-based treatment approaches for substance misuse problems and mental health that have developed and historically offered separately and in parallel.
Ghrelin Is Involved in the Decidualization of Human Endometrial Stromal Cells
Authors: Tanaka Keisuke , Minoura Hiroyuki , Isobe Tetsuya , Yonaha Hitoshi , Kawato Hiroaki , Wang Dong Fang , Yoshida Toshimichi , Kojima Masayasu , Kangawa Kenji , Toyoda Nagayasu
Published: May 2003

Successful implantation involves a complex interaction between the endometrium and the embryo. It is well known that several neuropeptides are expressed in the endometrium and placenta during embryonal implantation, suggesting an important role as chemical mediators of the feto-maternal relationship. Ghrelin has recently been identified as the endogenous ligand for the GH secretagogue receptor. Ghrelin is a peptide hormone with many physiological functions, and its expression in the human placenta has been reported. To investigate the involvement of ghrelin in embryonal implantation, we assessed the spatio-temporal expression pattern of ghrelin and its receptor in the human endometrium and placenta through the normal menstrual cycle and in early pregnancy. We also examined the effect of ghrelin on the decidualization of endometrial stromal cells (ESC). Weak expression of ghrelin mRNA was detected in the nonpregnant endometrium, and it was dramatically increased in the decidualized endometrium. A GH secretagogue receptor mRNA was detected in the endometrium throughout the normal menstrual cycle and in early pregnancy, but not in the first trimester placenta. Immunohistochemical analysis using an antighrelin antibody revealed strong signals in decidual cells and extravillous trophoblast cells. Coculture with first trimester placenta up-regulated ghrelin mRNA expression by primary cultured ESC, although sex steroids and 8-bromo-cAMP had no effect. In addition, ghrelin enhanced the decidualization of ESC induced by 8-bromo-cAMP (8-Br-cAMP) in vitro. Thus, ghrelin is a novel paracrine/autocrine factor that is involved in cross-talk between the endometrium and embryo during embryonal implantation.
A Model to Determine Workforce Needs for Endocrinologists in the United States Until 20201
Authors: Rizza Robert A. , Vigersky Robert A. , Rodbard Helena W. , Ladenson Paul W. , Young Jr. William F. , Surks Martin I. , Kahn Richard , Hogan Paul F.
Published: May 2003

The objective of this study was to define the workforce needs for the specialty of endocrinology, diabetes, and metabolism in the United States between 1999 and 2020.

An interactive model of factors likely to influence the balance between the supply and demand of endocrinologists during the next 20 yr was constructed. The model used data from a wide range of sources and was developed under the guidance of a panel of experts derived from sponsoring organizations of endocrinologists. We determined current and projected numbers and demographics of endocrinologists in the United States workforce and the anticipated balance between supply and demand from 1999 to 2020. There were 3,623 adult endocrinologists in the workforce in 1999, of which 2,389 (66%) were in office-based practice. Their median age was 49 yr. Both total office visits and services performed by endocrinologists (particularly for diabetes) increased substantially during the 1990s. Waiting time for an initial appointment is presently longer for endocrinologists than for other physicians. Compared with a balanced, largely closed-staff health maintenance organization, the current national supply of endocrinologists is estimated to be 12% lower than demand. The number of endocrinologists entering the market has continuously fallen over the previous 5 yr, from 200 in 1995 to 171 in 1999. Even if this downward trend were abruptly stopped, the model predicts that demand will exceed supply from now until 2020. Whereas this gap narrows from 2000 to 2008 due to projected growth of managed care, it widens thereafter due to the aging of both the population and the endocrine workforce. Inclusion of other factors such as projected real income growth and increased prevalence of age-related endocrine disorders (e.g. diabetes and osteoporosis) further accentuates the deficit. If the number of endocrinologists entering the workforce remains at 1999 levels, demand will continue to exceed supply from now through 2020 for adult endocrinologists, and the gap will widen progressively from 2010 onward. The present analysis indicates that the number of endocrinologists entering the workforce will not be sufficient to meet future demand. These data suggest that steps should be taken to stop the ongoing decline in the number of endocrinologists in training and consideration should be given to actions designed to increase the number of endocrinologists in practice in the years ahead.
PDS Is a New Susceptibility Gene to Autoimmune Thyroid Diseases: Association and Linkage Study
Authors: Kacem Hassen Hadj , Rebai Ahmed , Kaffel Noureddine , Masmoudi Saber , Abid Mohamed , Ayadi Hammadi
Published: May 2003

Autoimmune thyroid disease (AITD), including Graves’ disease (GD), Hashimoto thyroiditis (HT), and primary idiopathic myxedema, is caused by multiple genetic and environmental factors. Genes involved in immune response and/or thyroid physiology appear to influence susceptibility to disease. The PDS gene (7q31), responsible for Pendred syndrome (congenital sensorineural hearing loss and goiter), encodes a transmembrane protein known as pendrin. Pendrin is an apical porter of iodide in the thyroid. To evaluate the contribution of PDS gene in the genetic susceptibility of AITD, we examined four microsatellite markers in the gene region. Two hundred thirty-three unrelated patients (GD,141; HT, 54; primary idiopathic myxedema, 38), 15 multiplex AITD families (104 individuals/46 patients) and 154 normal controls were genotyped. Analysis of case-control data showed a significant association of D7S496 and D7S2459 with GD (P = 10−3) and HT (P = 1.07 10−24), respectively. The family-based association test showed significant association and linkage between AITDs and alleles 121 bp of D7S496 and 173 bp of D7S501. Results obtained by transmission disequilibrium test are in good agreement with those obtained by the family-based association test. Indeed, evidence for linkage and association of allele 121 bp of D7S496 with AITD was confirmed (P = 0.0114). Multipoint nonparametric linkage analysis using MERLIN showed intriguing evidence for linkage with marker D7S496 in families with only GD patients [Z = 2.12, LOD = 0.81, P = 0.026]. Single-point and multipoint parametric LOD score linkage analysis was also performed. Again, the highest multipoint parametric LOD score was found for marker D7S496 (LOD = 1.23; P = 0.0086) in families segregating for GD under a dominant model. This work suggests that the PDS gene should be considered a new susceptibility gene to AITDs with varying contributions in each pathology.
Nephrolithiasis in Cushing’s Disease: Prevalence, Etiopathogenesis, and Modification after Disease Cure
Authors: Faggiano Antongiulio , Pivonello Rosario , Melis Daniela , Filippella Mariagiovanna , Di Somma Carolina , Petretta Mario , Lombardi Gaetano , Colao Annamaria
Published: May 2003

The pathogenesis of nephrolithiasis in Cushing’s syndrome is still not completely clarified. The current study aimed at investigating prevalence of nephrolithiasis and role of different lithogenic factors in Cushing’s disease (CD). Forty-six CD patients (24 with active and 22 with cured disease) and 46 sex- and age-matched controls entered the study. Body mass index, blood pressure, fasting glucose and insulin, serum and urinary creatinine, urea, uric acid, electrolytes, and cystine, urinary volume, pH, oxalate, and citrate levels, and renal ultrasonography (US) were performed in all patients and controls. Nephrolithiasis was found in 50% of active patients, 27.3% of cured patients, and 6.5% of controls (P < 0.001). Compared with controls, patients with active disease had a significantly increased prevalence of obesity, arterial hypertension, diabetes mellitus, hypercalciuria, hypocitraturia, and hyperuricosuria, significantly higher levels of serum and urinary cystine, urinary creatinine, urea, uric acid, potassium, calcium, phosphorus, and oxalate, significantly lower levels of urinary citrate levels. Compared with controls, patients cured from CD had a significantly increased prevalence of obesity, systemic arterial hypertension, and diabetes mellitus, whereas urinary citrate was significantly decreased. At multivariate analysis, a significantly increased risk to develop kidney stones was independently associated with urinary excretion of uric acid (odds ratio = 1.6, confidence interval = 1.0–2.5) and systemic arterial blood pressure (odds ratio = 2.6, confidence interval = 1.1–6.6).

In conclusion, patients with active CD have an increased prevalence of nephrolithiasis compared with general population, which decreases but not disappears in patients successfully cured from the disease. This complication is likely caused by the synergic effect of different hypercortisolism-dependent metabolic and hemodynamic abnormalities, among which systemic arterial hypertension and excessive urinary uric acid excretion seem to play a pivotal role.
Clinical Features and Outcome of Subacute Thyroiditis in an Incidence Cohort: Olmsted County, Minnesota, Study
Authors: Fatourechi Vahab , Aniszewski Jaroslaw P. , Fatourechi Guiti Z. Eghbali , Atkinson Elizabeth J. , Jacobsen Steven J.
Published: May 2003

Subacute thyroiditis (SAT), or granulomatous thyroiditis, is an inflammatory thyroid condition associated with pain and systemic symptoms. Few community studies are available. We studied the 160 patients with SAT in Olmsted County, Minnesota, seen between January 1, 1960, and December 30, 1997. Subjects were identified through the medical diagnostic index of the Rochester Epidemiology Project. The overall age- and sex-adjusted incidence from 1960 through 1997 was 4.9 cases per 100,000/yr. In the most recent 28-yr period (1970–1997), 94 patients were identified. In this group, pain was the presenting symptom in 96%. SAT recurred in 4% of the patients 6–21 yr after the initial episode. Corticosteroid therapy was given to 36%. Early-onset hypothyroidism occurred both in patients receiving corticosteroid therapy (29%) and in those not receiving corticosteroid therapy (37%). At latest follow-up, significantly more patients who had received corticosteroid therapy had a diagnosis of hypothyroidism than the group without corticosteroid therapy (25% vs. 10%, P < 0.05; overall rate of hypothyroidism, 15%). Early transient hypothyroidism is common in SAT. Permanent hypothyroidism is less common, and only 15% of the patients are receiving T4 therapy after 28 yr of follow-up. Symptomatic relief is achieved with corticosteroid therapy, but such therapy does not prevent early- and late-onset thyroid dysfunction.
Structure and Function of Disease-Causing Missense Mutations in the PHEX Gene
Authors: Sabbagh Yves , Boileau Guy , Campos Marcelo , Carmona Adriana K. , Tenenhouse Harriet S.
Published: May 2003

The PHEX gene that is mutated in patients with X-linked hypophosphatemia (XLH) encodes a protein homologous to the M13 family of zinc metallopeptidases. The present study was undertaken to assess the impact of nine PHEX missense mutations on cellular trafficking, endopeptidase activity, and protein conformation. Secreted forms of wild-type and mutant PHEX proteins were generated by PCR mutagenesis; these included C85R, D237G, Y317F, G579R, G579V, S711R, A720T, and F731Y identified in XLH patients, and E581V, which in neutral endopeptidase 24.11 abolishes catalytic activity but not plasma membrane localization. The wild-type and D237G, Y317F, E581V, and F731Y proteins were terminally glycosylated and secreted into the medium, whereas the C85R, G579R, G579V, S711R, and A720T proteins were trapped inside the transfected cells. Growing the cells at 26 C permitted the secretion of G579V, S711R, and A720T proteins, although the yield of rescued G579V was insufficient for further analysis. Endopeptidase activity of secreted and rescued PHEX proteins, assessed using a novel internally quenched fluorogenic peptide substrate, revealed that E581V and S711R are completely inactive; D237G and Y317F exhibit 50–60% of wild-type activity; and A720T and F731Y retain full catalytic activity. Conformational analysis by limited proteolysis demonstrated that F731Y is more sensitive to trypsin and D237G is more resistant to endoproteinase Glu-c than the wild-type protein. Thus, defects in protein trafficking, endopeptidase activity, and protein conformation account for loss of PHEX function in XLH patients harboring these missense mutations.
Human Myometrial Quiescence and Activation during Gestation and Parturition Involve Dramatic Changes in Expression and Activity of Particulate Type II (RIIα) Protein Kinase A Holoenzyme
Authors: MacDougall Malcolm. W. J. , Europe-Finner G. Nicholas , Robson Stephen. C.
Published: May 2003

There are substantial data indicating that components of the cAMP-signaling pathway are differentially expressed in the human myometrium during pregnancy. The effects of cAMP in most tissues and cell types are mainly modulated via protein kinase A, a heterotetrameric protein complex consisting of two regulatory (R) and two catalytic (C) subunits. In the studies presented here, we used specific antibodies in Western blotting/immunoprecipitation, RT-PCR, and functional protein kinase A (PKA) phosphorylation assays to determine the PKA holoenzymes that are expressed in the human myometrium throughout pregnancy and labor. We report that as early as the second trimester of pregnancy, there is a significant increase in expression of the regulatory RIIα protein subunit of PKA in the myometrium. This increase in protein expression is also mirrored at the mRNA level, indicating transcriptional control throughout pregnancy, whereas during parturition both transcript and protein are significantly decreased. This increase in RIIα protein also resulted in increased particulate PKA activity in the myometrium during gestation, which was subsequently decreased during labor. Two specific A kinase anchoring proteins, AKAP95 and AKAP79, which have high binding affinities for RIIα subunits, were found to form complexes with myometrial RIIα species employing immunoprecipitation assays, but their levels of expression remained uniform in all myometrial tissue samples investigated. Our findings indicate that increased particulate type II PKA activity occurs throughout pregnancy, therefore directing the cAMP quiescence signal to specific subcellular loci within myometrial smooth muscle cells including the contractile machinery at the cytoskeleton; this effect is then removed during parturition.
Resveratrol transport and metabolism by human intestinal Caco-2 cells
Authors: Kaldas Mark I , Walle U Kristina , Walle Thomas
Published: May 2003

Resveratrol is a dietary constituent suggested to have protective effects against cancer as well as cardiovascular disease. The purpose of the study was to learn whether this agent could be absorbed in man and enter the systemic circulation. This was examined by measuring transport and metabolism of resveratrol (5–40 μM) by the human intestinal epithelial cell line Caco-2 cultured in Transwells. Transport across the Caco-2 monolayer occurred in a direction-independent manner with Papp values of ≅ 7 times 10−6 cm s−1, much higher than for the paracellular transport marker mannitol (≅ 0.4 times 10−6 cms−1), suggesting efficient absorption in-vivo. At the highest resveratrol concentration, the absorption increased, possibly due to saturation of metabolism. In sharp contrast to previous findings in the rat, the metabolism of resveratrol in Caco-2 cells involved mainly sulfation and, to a minor extent, glucuronidation. At low resveratrol concentrations, most of the sulfate conjugate was exported to the apical side, presumably by MRP2, which is well expressed in these cells. At high concentrations, there was a shift towards the basolateral side, possibly involving MRP3, which was recently shown also to be expressed in Caco-2 cells. These results indicate that absorption of resveratrol in-vivo may be high but with limited bioavailability due to efficient sulfate conjugation. Extensive accumulation of resveratrol in the Caco-2 cells, demonstrated in additional experiments, suggests enterocytes as a major target site for this cancer preventive agent.
Quercetin, a phytoestrogen and dietary flavonoid, activates different membrane-bound guanylate cyclase isoforms in LLC-PK1 and PC12 cells
Authors: Chen Zi-Jiang , Vetter Michael , Chang Geen-Dong , Liu Shiguo , Chang Chung-Ho
Published: May 2003

Accumulated evidence suggests that quercetin, a dietary flavonoid, has beneficial effects in protection against cardiovascular diseases and in the inhibition of tumour growth. We have recently shown that antioxidants such as 17β-estradiol, resveratrol, dithiothreitol and vitamin C activate membrane-bound guanylate cyclase GC-A, a receptor for atrial natriuretic factor (ANF). Since quercetin is a phytoestrogen and potent antioxidant, it is possible that it may activate GC-A or other guanylate cyclase isoforms. We examined whether quercetin activates GC-A or GC-B (the receptor for C-type natriuretic peptide, CNP) in PC12 and porcine kidney proximal tubular LLC-PK1 cells. The results showed that quercetin activated a guanylate cyclase isoform in both cell types. Quercetin inhibited CNP-stimulated GC-B activity, but had little effect on ANF-stimulated GC-A activity in PC12 cells, suggesting that quercetin mainly activates GC-B in PC12 cells. In contrast, CNP had no effect on guanylate cyclase activity in LLC-PK1 cells, indicating that GC-B is not expressed in LLC-PK1 cells. Furthermore, quercetin had a small effect on ANF-stimulated GC-A activity and had no effect on soluble guanylate cyclase activity in LLC-PK1 cells, suggesting that quercetin does not activate GC-A, GC-B or soluble guanylate cyclase in LLC-PK1 cells. However, quercetin did stimulate membrane-bound guanylate cyclase activity in LLC-PK1 cell membranes. These results indicate that quercetin activates the GC-B isoform in PC12 cells, but activates an unknown membrane-bound guanylate cyclase isoform in LLC-PK1 cells.
Endothelium-dependent and -independent vasodilator effects of eugenol in the rat mesenteric vascular bed
Authors: Criddle David Neil , Madeira Socorro Vanesca Frota , de Moura Roberto Soares
Published: May 2003

The possible involvement of the endothelium in the vasodilator action of eugenol was investigated in the mesenteric vascular bed (MVB) of the rat. Bolus injections of eugenol (0.2, 2 and 20 μmol) and acetylcholine (ACh; 10, 30 and 100 pmol) induced dose-dependent vasodilator responses in noradrenaline-precontracted beds that were partially inhibited by pretreatment of the MVB with deoxycholate (1 mg mL−1) to remove the endothelium (˜ 14% and ˜ 30% of the control response remaining at the lowest doses of ACh and eugenol, respectively). The vasodilator effect of glyceryl trinitrate (1 μmol) was unaltered by deoxycholate. In the presence of either Nω-nitro-L-arginine methyl ester (300 μM) or tetra-ethylammonium (1 mM) the response to ACh was partially reduced, whereas eugenol-induced vasodilation was unaffected. Similarly the vasodilator effect of eugenol was not inhibited by indometacin (3 μM). Under calcium-free conditions the vasoconstrictor response elicited by bolus injections of noradrenaline (10 nmol) was dose-dependently and completely inhibited by eugenol (0.1–1 mM). Additionally, the pressor effects of bolus injections of calcium chloride in potassium-depolarized MVBs were greatly reduced in the presence of eugenol (0.1 mM), with a maximal reduction of ˜ 71% of the control response. Our data showed that eugenol induced dose-dependent, reversible vasodilator responses in the rat MVB, that were partially dependent on the endothelium, although apparently independent of nitric oxide, endothelium-derived hyperpolarizing factor or prostacyclin. Furthermore, an endothelium-independent intracellular site of action seemed likely to participate in its smooth muscle relaxant properties.
Dual effect of agmatine in the bisected rat vas deferens
Authors: Santos Wilson C , Smaili Soraya S , Jurkiewicz Aron , Piçarro Ivan , Garcez-do-Carmo Lúcia
Published: May 2003

The functional effects of the amine agmatine, the putative endogenous ligand for α2-adrenoceptors and imidazoline receptors, in rat vas deferens were investigated by using the epididymal and prostatic portions. Tissues were contracted by electrical stimulation or by exogenous drugs. In electrically stimulated portions, agmatine caused a dual effect on contractions. In the epididymal portion an inhibition on twitch contractions was observed, which was partially antagonised by idazoxan and yohimbine, indicating the involvement of at least a presynaptic α2-adrenoceptor-mediated mechanism, without the interference of imidazoline receptors. In the prostatic portion, agmatine enhanced the amplitude of twitches. In contractions induced by exogenous drugs, agmatine potentiated, only in the prostatic segment, the effects of noradrenaline (norepinephrine) or ATP; it also enhanced the effect of low concentrations of KCl and blocked the maximum effect of the higher concentrations. Effects induced by agmatine on the exogenous ATP in the prostatic portion were blocked by cromakalim, suggesting a blocking action on the postsynaptic K+ channels, which explains, in part, the potentiation of the twitch amplitude. It was concluded that agmatine interferes with sympathetic neurotransmission, but the physiological relevance of this needs to be better understood because of the high doses employed to induce its effects.
Apparent mechanism-based inhibition of human CYP3A in-vitro by lopinavir
Authors: Weemhoff James L , von Moltke Lisa L , Richert Clemens , Hesse Leah M , Harmatz Jerold S , Greenblatt David J
Published: May 2003

The influence of the viral protease inhibitor lopinavir on the activity of six human cytochrome P450 (CYP) enzymes was evaluated in a model system using human liver microsomes. Column chromatography methodology was developed to separate lopinavir from ritonavir starting from the commercially available lopinavir-ritonavir combination dosage form. Lopinavir produced negligible or weak inhibition of human CYP1A2, 2B6, 2C9, 2C19 and 2D6. However, lopinavir was an inhibitor of CYP3A. At 250 μM triazolam (the CYP3A index substrate), the mean (± s.e., n = 4) IC50 versus triazolam α-hydroxylation (where IC50 is the concentration producing a 50% decrement in reaction velocity) was 7.3 (± 0.5) μM. Pre-incubation of lopinavir with microsomes prior to addition of triazolam yielded a significantly lower IC50 of 4.1 (± 0.5) μM. This is consistent with mechanism-based inhibition of human CYP3A by lopinavir. Although lopinavir is less potent than ritonavir as an inhibitor of CYP3A, lopinavir is nonetheless likely to contribute to net CYP3A inhibition in-vivo during treatment with the lopinavir-ritonavir combination.
Archvillin, a muscle-specific isoform of supervillin, is an early expressed component of the costameric membrane skeleton
Authors: Oh Sang W. , Pope Robert K. , Smith Kelly P. , Crowley Jessica L. , Nebl Thomas , Lawrence Jeanne B. , Luna Elizabeth J.
Published: May 2003

The membrane skeleton protein supervillin binds tightly to both F-actin and membranes and can potentiate androgen receptor activity in non-muscle cells. We report that muscle, which constitutes the principal tissue source for supervillin sequences, contains a ∼250 kDa isoform of supervillin that localizes within nuclei and with dystrophin at costameres, regions of F-actin membrane attachment in skeletal muscle. The gene encoding this protein,`archvillin' (Latin, archi; Greek, árchos; `principal' or `chief'),contains an evolutionarily conserved, muscle-specific 5′ leader sequence. Archvillin cDNAs also contain four exons that encode ∼47 kDa of additional muscle-specific protein sequence in the form of two inserts within the function-rich N-terminus of supervillin. The first of these muscle-specific inserts contains two conserved nuclear targeting signals in addition to those found in sequences shared with supervillin. Archvillin, like supervillin, binds directly to radiolabeled F-actin and co-fractionates with plasma membranes. Colocalization of archvillin with membrane-associated actin filaments, non-muscle myosin II, and – to a lesser extent –vinculin was observed in myoblasts. Striking localizations of archvillin protein and mRNA were observed at the tips of differentiating myotubes. Transfected protein chimeras containing archvillin insert sequences inhibited myotube formation, consistent with a dominant-negative effect during early myogenesis. These data suggest that archvillin is among the first costameric proteins to assemble during myogenesis and that it contributes to myogenic membrane structure and differentiation.
Decreased intercellular dye-transfer and downregulation of non-ablated connexins in aortic endothelium deficient in connexin37 or connexin40
Authors: Simon Alexander M. , McWhorter Andrea R.
Published: May 2003

Vascular endothelial cells are coupled by gap junctions that permit cell-to-cell transfer of small molecules, including signals that may be important for vasomotor responses. Connexin37 (Cx37) and connexin40 (Cx40) are the predominant gap-junction proteins present in mouse endothelium. We examined the effect of eliminating Cx37, Cx40, or both, on interendothelial communication in mouse aorta. Intercellular transfer of biocytin and[2-(4-nitro-2,1,3-benzoxadiazol-7-yl)aminoethyl]trimethylammonium (NBD-TMA)was used to assess gap-junction-mediated coupling. Ablation of Cx40 generally had a greater effect on dye-transfer than ablation of Cx37. The effect of Cx40 ablation on dye-transfer was age dependent. There was a 27-fold reduction in biocytin transfer in embryonic Cx40–/– aortic endothelium, a much larger change than in aortas of 6-7-week-old Cx40–/– animals, which showed a 3.5-fold reduction. By contrast, there was no reduction in biocytin transfer in embryonic Cx37–/– endothelium. Embryonic aortas lacking both Cx37 and Cx40 showed a complete loss of endothelial dye-transfer. Surprisingly,elimination of Cx40 resulted in up to a 17-fold drop in endothelial Cx37 on western blots, whereas deletion of Cx37 reduced endothelial Cx40 up to 4.2-fold. By contrast, in the medial layer, both Cx37 and Cx43 increased∼fourfold in Cx40–/– aortas. Declines in non-ablated endothelial connexins were not mediated by changes in connexin mRNA levels, suggesting a post-transcriptional effect. Our results indicate that Cx37 and Cx40 are the only functional connexins expressed in mouse aortic endothelium and are collectively crucial for endothelial communication. Furthermore, Cx37 and Cx40 are codependent on each other for optimal expression in vascular endothelium.
Infertility in female mice with an oocyte-specific knockout of GPI-anchored proteins
Authors: Alfieri Jennifer A. , Martin Arlan D. , Takeda Junji , Kondoh Gen , Myles Diana G. , Primakoff Paul
Published: May 2003

Glycosylphosphatidylinositol-anchored proteins on the egg surface have been proposed to play a role in gamete fusion on the basis of in vitro experiments. We tested this hypothesis by asking if oocyte GPI-anchored proteins are required for fertilization in vivo. Oocyte-specific knockout mice were created using the Cre/loxP system to delete a portion of the Pig-agene, which encodes an enzyme involved in GPI anchor biosynthesis. Conditional Pig-a-knockout females are infertile, and eggs recovered from the females after mating are unfertilized. In in vitro assays, the knockout eggs are severely deficient in their ability to fuse with sperm. These results demonstrate that GPI-anchored proteins are required for gamete fusion. Loss of the GPI-anchored complement of plasma membrane proteins could prevent fusion by altering the organization and function of GPI-anchored protein-containing lipid domains. Alternatively, a single GPI-anchored protein may be required in the fusion process. To distinguish between these possibilities, we have begun to identify the GPI-anchored proteins on the egg surface. We have identified one egg GPI-anchored protein as CD55, an ∼70 kDa complement regulatory protein. It has previously been found that CD55-knockout mice are fertile,demonstrating that CD55 is not essential for fertilization. This finding also means that the presence of the full complement of egg GPI-anchored proteins is not necessary for gamete fusion. Other egg GPI-anchored proteins acting in the fusion process can now be investigated, with the goal of understanding the mechanism of their function in sperm-egg fusion.
Differential regulation of cell adhesive functions by integrin αsubunit cytoplasmic tails in vivo
Authors: Na Jie , Marsden Mungo , DeSimone Douglas W.
Published: May 2003

Cell adhesion to fibronectin (FN) is crucial for early vertebrate morphogenesis. In Xenopus gastrulae, several distinct integrin-dependent adhesive behaviors can be identified: adhesion of cells to FN, assembly of FN fibrils, and initiation of cell spreading and migration in response to mesoderm inducing signals. We have taken a chimeric integrin approach to investigate the role of the integrin α cytoplasmic tail in the specification of these developmentally significant adhesive functions. Cytoplasmic tail-deleted α4 constructs andα4-ectodomain/α-cytoplasmic tail chimeras were generated and expressed in whole embryos. Normal gastrula cells lack integrin α4 and,correspondingly, are unable to adhere to the α4 ligand, the V-region of FN. The ability of α4 constructs to promote adhesive behaviors was established by placing tissue explants or dissociated cells on an FN V-region fusion protein that lacks the RGD (Arg-Gly-Asp)/synergy sites or treating whole embryos with antibodies that block endogenous integrin-FN interactions. We found that each α4 cytoplasmic domain deletion mutant andα-tail chimera examined could support cell attachment; however, activin induction-dependent cell spreading, mesoderm cell and explant motility, and the ability to assemble FN matrix on the blastocoel roof varied with specificα subunit tail sequences. These data suggest that α cytoplasmic tail signaling and changes in integrin activation state can regulate a variety of developmentally significant adhesive behaviors in both space and time.
Rapid transport of neural intermediate filament protein
Authors: Helfand Brian T. , Loomis Patty , Yoon Miri , Goldman Robert D.
Published: May 2003

Peripherin is a neural intermediate filament protein that is expressed in peripheral and enteric neurons, as well as in PC12 cells. A determination of the motile properties of peripherin has been undertaken in PC12 cells during different stages of neurite outgrowth. The results reveal that non-filamentous, non-membrane bound peripherin particles and short peripherin intermediate filaments, termed `squiggles', are transported at high speed throughout PC12 cell bodies, neurites and growth cones. These movements are bi-directional, and the majority require microtubules along with their associated molecular motors, conventional kinesin and cytoplasmic dynein. Our data demonstrate that peripherin particles and squiggles can move as components of a rapid transport system capable of delivering cytoskeletal subunits to the most distal regions of neurites over relatively short time periods.
Effects of load type (pollen or nectar) and load mass on hovering metabolic rate and mechanical power output in the honey beeApis mellifera
Authors: Feuerbacher Erica , Fewell Jennifer H. , Roberts Stephen P. , Smith Elizabeth F. , Harrison Jon F.
Published: May 2003

In this study we tested the effect of pollen and nectar loading on metabolic rate (in mW) and wingbeat frequency during hovering, and also examined the effect of pollen loading on wing kinematics and mechanical power output. Pollen foragers had hovering metabolic rates approximately 10% higher than nectar foragers, regardless of the amount of load carried. Pollen foragers also had a more horizontal body position and higher inclination of stroke plane than measured previously for honey bees (probably nectar foragers). Thorax temperatures ranked pollen > nectar > water foragers,and higher flight metabolic rate could explain the higher thorax temperature of pollen foragers. Load mass did not affect hovering metabolic rate or wingbeat frequency in a regression-model experiment. However, using an analysis of variance (ANOVA) design, loaded pollen and nectar foragers (mean loads 27% and 40% of body mass, respectively) significantly increased metabolic rate by 6%. Mean pollen loads of 18% of body mass had no effect on wingbeat frequency, stroke amplitude, body angle or inclination of stroke plane, but increased the calculated mechanical power output by 16–18%(depending on the method of estimating drag). A rise in lift coefficient as bees carry loads without increasing wingbeat frequency or stroke amplitude(and only minimal increases in metabolic rate) suggests an increased use of unsteady power-generating mechanisms.
Comparative analysis of DNA vectors at mediating RNAi in Anopheles mosquito cells and larvae
Authors: Brown Anthony E. , Crisanti Andrea , Catteruccia Flaminia
Published: May 2003

Heritable RNA interference (RNAi) mediated by transgenes exhibiting dyad symmetry represents an important tool to study the function of genes expressed at late developmental stages. In this study, we determined whether the transcriptional machinery of Anopheles mosquitoes is capable of directing suppression of gene expression from DNA constructs designed to transcribe double-stranded RNA (dsRNA) as extended hairpin-loop RNAs. A series of DNA vectors containing sense and antisense regions of the green fluorescent protein EGFP target gene was developed. The effect of these vectors on a transiently expressed or stably integrated EGFP gene was assessed in an Anopheles gambiae cell line and in Anopheles stephensi larvae. Our data indicate that dsRNA-mediated silencing of a target gene from plasmid DNA can be achieved at high levels in Anopheles cell lines and larvae. The region that links the sense and antisense sequences of the target gene plays a determining role in the degree of silencing observed. These results provide important information for the development of heritable RNAi in Anopheles.
Mechanisms of frequency and amplitude modulation in ring dove song
Authors: Beckers Gabriël J. L. , Suthers Roderick A. , Cate Carel ten
Published: May 2003

Birdsong assumes its complex and specific forms by the modulation of phonation in frequency and time domains. The organization of control mechanisms and intrinsic properties causing such modulation have been studied in songbirds but much less so in non-songbirds, the songs of which are often regarded as relatively simple. We examined mechanisms of frequency and amplitude modulation of phonation in ring doves Streptopelia risoria,which are non-songbirds. Spontaneous coo vocalizations were recorded together with concurrent pressure patterns in two different air sacs and air flow rate in the trachea. The results show that amplitude modulation is the result of the cyclic opening and closure of a valve instead of fluctuations in driving pressure, as is the current explanation. Frequency modulation is more complex than previously recognized and consists of gradual, continuous time–frequency patterns, punctuated by instantaneous frequency jumps. Gradual frequency modulation patterns correspond to pressure variation in the interclavicular air sac but not to pressure variation in the cranial thoracic air sac or air flow rate variation in the trachea. The cause of abrupt jumps in frequency has not been identified but can be explained on the basis of intrinsic properties of the vocal organ. Air sac pressure variation as a mechanism for frequency modulation contrasts with the specialized syringeal musculature of songbirds and may explain why the fundamental frequency in non-songbird vocalizations is generally modulated within a limited frequency range.