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PubMed2002

Isolation and structure-function studies of a glucagon-like peptide 1 receptor from goldfish Carassius auratus: identification of three charged residues in extracellular domains critical for receptor function.

A better understanding of the molecular mechanism of ligand-receptor interaction of glucagon-like peptide 1 (GLP-1) receptors (GLP-1Rs) is useful for the design of potent GLP-1 analogs that could potentially be used as a treatment for diabetic patients. Changes in the ligand and receptor sequences during evolution provide invaluable clues to evaluate the functional motifs of the receptor that are responsible for ligand interaction. For these reasons, in the present study, we have isolated and functionally characterized a GLP-1R from goldfish. Its amino acid sequence shows 50.8% and 52.3% identity with the human glucagon (hGLU) and GLP-1Rs, respectively, and 84.1% with the zebrafish GLP-1R (the only other GLP-1R isolated from teleost fish). Peptides that are structurally different from goldfish (gf)GLP-1, such as gfGLU and hGLU and human GLP-1 (7-36)amide, are also capable of stimulating this receptor, albeit with lower potencies than gfGLP-1. gfGLP-1 stimulates the formation of cAMP through the recombinant gfGLP-1R with EC(50) = 0.18 nM, whereas EC(50) values for gfGLU, human GLP-1 (7-36)amide, and hGLU are 0.53 nM, 0.9 nM, and 1.2 nM, respectively. These results indicate that the gfGLP-1R is structurally more flexible than its mammalian counterpart and that its binding pocket can accommodate a wider spectrum of peptide ligands. Previous studies demonstrated that the charged residues in the extracellular domains of mammalian GLP-1R, particularly those found in the N-terminal domain and the first exoloop, are important for ligand binding. We investigated the roles of the conserved charged residues in the function of the gfGLP-1R. Eleven mutant receptors were constructed, and the effects of mutations were determined by functional assays. Our results demonstrated that three charged residues (D(113), R(197), and D(205)) present in the extracellular domains are critical for receptor function.

Amino Acid Sequence↗

PubMed2001

Comparison of measured and estimated indices of insulin sensitivity and beta cell function: impact of ethnicity on insulin sensitivity and beta cell function in glucose-tolerant and normotensive subjects.

Type 2 diabetes mellitus is the result of an imbalance between insulin sensitivity and beta cell function. Although the assessment of these 2 parameters is critical for various studies, the current methods are time consuming and labor intensive. Recently, new estimated indices have been proposed. We examined the impact of ethnicity on the indices of insulin sensitivity and beta cell function measured from the hyperglycemic clamp and compared the results to the estimated indices, proposed by Matsuda and DeFronzo and Stumvoll et al., from a standard oral glucose tolerance test in 105 healthy, glucose-tolerant, and normotensive subjects from 4 ethnic groups. Among the ethnic groups, differences were noted in the measured insulin sensitivity (P = 0.0006) and beta cell function (P = 0.006 for the first phase insulin response, P = 0.0002 for the second phase insulin response). Although the estimated indices correlated with the measured indices (r(2) = 0.5184--0.3014), the estimated indices barely detected the differences among the ethnic groups. Multivariate analysis confirmed that ethnicity had an independent impact for the measured indices, but had only a modest impact on the estimated insulin sensitivity indices and had no impact on the estimated indices of beta cell function. We conclude that although the estimated indices of insulin sensitivity and beta cell function from the oral glucose tolerance test correlated with the measured ones in a wide spectrum of healthy, glucose-tolerant, and normotensive subjects, they were much less likely to detect the differences than measured ones among the ethnic groups.

Adolescent↗

PubMed2006

Functional genomics in Dictyostelium: MidA, a new conserved protein, is required for mitochondrial function and development.

Genomic sequencing has revealed a large number of evolutionary conserved genes of unknown function. In the absence of characterized functional domains, the discovery of the role of these genes must rely on experimental approaches. We have selected 30 Dictyostelium discoideum genes of unknown function that showed high similarity to uncharacterized human genes and were absent in the complete proteomes from Saccharomyces cerevisiae and S. pombe. No putative functional motifs were found in their predicted encoded proteins. Eighteen genes were successfully knocked-out and three of them showed obvious phenotypes. A detailed analysis of one of them, midA, is presented in this report. Disruption of midA in Dictyostelium leads to pleiotropic defects. Cell size, growth rate, phagocytosis and macropinocytosis were affected in the mutant. During development, midA- cells showed an enhanced tendency to remain at the slug stage, and spore viability was compromised. The expression of MidA fused to GFP in midA- strain rescued the phenotype and the fused protein was located in the mitochondria. Although cellular oxygen consumption, mitochondrial content and mitochondrial membrane potential were similar to wild type, the amount of ATP was significantly reduced in the mutant suggesting a mitochondrial dysfunction. Metabolomic analysis by natural-abundance 13C-nuclear magnetic resonance has shown the lack of glycogen accumulation during growth. During starvation, mutant cells accumulated higher levels of ammonia, which inhibited normal development. We hypothesize that the lack of MidA reduces mitochondrial ATP synthetic capacity and this has an impact in some but not all energy-dependent cellular processes. This work exemplifies the potential of Dictyostelium as a model system for functional genomic studies.

Amino Acid Sequence↗

PubMed1985

[Effects of Young's solution (YNG solution) on cardiac function and mitochondrial function during one hour ischemia at 30 degrees C and after reperfusion].

In a previous paper from this laboratory, protective effects of YNG solution on the myocardial mechanical function and metabolism of the heart arrested at 10 degrees C ascribable to the presence of Mg2+ were demonstrated. In order to further clarify the role played by Mg2+ in the protection, the present experiment was conducted using the isolated perfused guinea pig heart arrested at 30 degrees C. While the time to arrest of the contraction was equally short both with YNG (K+ + Mg2+) and K (K+) solutions, the time to resumption of contraction was significantly longer with K solution than with YNG solution, and the regular contraction was not resumed with the former solution. The recovery of the coronary flow, left ventricular pressure and dp/dt after reperfusion was around 100% with YNG solution, while the recovery was significantly poorer with K solution. Although the mitochondrial function was well maintained during the arrest both with YNG and K solution, the recovery of the mitochondrial function after reperfusion was observed only with YNG solution; severe damage was noted in mitochondria of the hearts arrested with K solution. There was a good correlation between the changes in mitochondrial function and those in cardiac function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2003

New methods to evaluate endothelial function: method for assessing endothelial function in humans using a strain-gauge plethysmography: nitric oxide-dependent and -independent vasodilation.

The vascular endothelium is involved in the release of various vasodilators, including nitric oxide (NO), prostaglandins, and endothelium-derived hyperpolarizing factor as well as vasoconstrictors. NO plays an important role in the regulation of vascular tone, the inhibition of platelet aggregation, and the suppression of smooth muscle cell proliferation. Several diseases are associated with changes in endothelial function mediated through reduced NO bioavailability. In addition, endothelial dysfunction is an early feature of atherosclerosis and vascular diseases in humans. Therefore, it is clinically important to estimate the degree of endothelial dysfunction. Several methods have been used to assess endothelial function in humans. Recently, we have evaluated the effects of intra-arterial infusion of infusion of NO agonists, such as acetylcholine, methacholine, and bradykinin, and NO antagonists on forearm blood flow using mercury-filled Silastic strain-gauge plethysmography. The response to the intra-arterial infusion of vasoactive agents should be considered the gold standard in assessing endothelial function, because the use of agonists to stimulate NO release allow us to draw more specific conclusions concerning the role of basal and stimulated NO release. However, the invasive method is time-consuming and is a burden for patients. A noninvasive method of measuring forearm blood flow response to reactive hyperemia also is useful in assessing endothelial function. In this review we would like to explain in detail the methods of assessing endothelial function in humans using strain-gauge plethysmography.

Endothelium, Vascular↗

PubMed2003

New methods to evaluate endothelial function: Non-invasive method of evaluating endothelial function in humans.

Evidence has accumulated that impairment of vascular endothelial function is the initial step in the development of atherosclerosis. One important finding is impairment of the release of endothelium-dependent relaxing factor, which is now thought to be nitric oxide or its related substances, from endothelial cells. Flow-mediated dilatation has been known to be endothelium-dependent, and this can be detected during reactive hyperemia by high-resolution ultrasound in superficial arteries. Several coronary risk factors have been reported to be significantly related with decreased flow-mediated dilatation. We studied the association between the accumulation of coronary risk factors (hyperlipidemia, diabetes mellitus, hypertension, and current smoking habitus) and vascular endothelial function. The lower incidence of atherosclerosis in women before the menopause than that in men is an established epidemiological observation. Short-term estrogen therapy improves endothelial function in postmenopausal women. However, there are few reports on its long-term effects on endothelial function. Furthermore, we determined whether a reduced dosage of estrogen may maintain its beneficial effects. A similar improvement was also observed while women were on hormone replacement therapy even at the reduced dosage. Our results indicate that even at half the dose of estrogen, hormone replacement therapy may improve endothelial function in postmenopausal women.

Brachial Artery↗

PubMed1992

[Characterization of thyroglobulin in a patient with functioning and non-functioning benign thyroid tumors].

The chemical and immunological properties of thyroglobulin (Tg) in tissue obtained from a patient co-existed with two types of thyroid tumors, i.e., functioning and non-functioning, and were compared with the properties of Tg that was isolated from adjacent peripheral tissue. In the present observations, the Tg content was markedly increased in the non-functioning thyroid tumor. On the other hand, the Tg content in the functioning tumor was at the normal level. The iodine content of Tg was significantly lower in the non-functioning tumor than in peripheral tissues. Affinity with Lectins differed among Tg preparations, suggesting that the carbohydrate chain in the Tg was different in each nodule in a single individual.

Adenoma↗

PubMed2003

Proliferation and functional maturation of Sertoli cells, and their relevance to disorders of testis function in adulthood.

Disorders of testicular function may have their origins in fetal or early life as a result of abnormal development or proliferation of Sertoli cells. Failure of Sertoli cells to mature, with consequent inability to express functions capable of supporting spermatogenesis, is a prime example. In a similar way, failure of Sertoli cells to proliferate normally at the appropriate period in life will result in reduced production of spermatozoa in adulthood. This review focuses on the control of proliferation of Sertoli cells and functional maturation, and is motivated by concerns about 'testicular dysgenesis syndrome' in humans, a collection of common disorders (testicular germ-cell cancer, cryptorchidism, hypospadias and low sperm counts) which are hypothesized to have a common origin in fetal life and to reflect abnormal function of Sertoli (and Leydig) cells. The timing of proliferation of Sertoli cells in different species is reviewed, and the factors that govern the conversion of an immature, proliferating Sertoli cell to a mature, non-proliferating cell are discussed. Protein markers of maturity and immaturity of Sertoli cells in various species are reviewed and their usefulness in studies of human testicular pathology are discussed. These markers include anti-Mullerian hormone, aromatase, cytokeratin-18, GATA-1, laminin alpha5, M2A antigen, p27(kip1), sulphated glycoprotein 2, androgen receptor and Wilms' tumour gene. A scheme is presented for characterization of Sertoli-cell only tubules in the adult testis according to whether or not there is inherent failure of maturation of Sertoli cells or in which the Sertoli cells have matured but there is absence, or acquired loss, of germ cells. Functional 'de-differentiation' of Sertoli cells is considered. It is concluded that there is considerable evidence to indicate that disorders of maturation of Sertoli cells may be a common underlying cause of human male reproductive disorders that manifest at various life stages. This recognition emphasizes the important role that animal models must play to enable identification of the mechanisms via which failure of proliferation and maturation of Sertoli cells can arise, as this failure probably occurs in fetal life.

Adult↗

PubMedDate not supplied

Assessment of sexual function in patients undergoing vasectomy using the international index of erectile function.

INTRODUCTION: The present study aims to prospectively compare the sexual function in males before and after vasectomy surgery using the international index of erectile function (IIEF). MATERIALS AND METHODS: From October to December 2002, sixty-four patients who were candidates for male sterilization in the vasectomy program of the Urology Section at the General Hospital of the University of São Paulo were included. The same investigator applied the IIEF before and 90 days after the surgery. The mean scores obtained on pre and postoperative visits for all domains of sexual function were analyzed and compared with the Wilcoxon test. RESULTS: The mean patient age was 35 years (range from 25 to 48 years) and the mean number of children per man was 3. The total mean score of the IIEF was 64.06 before surgery and 65.64 after the procedure, with this difference considered statistically significant (p < 0.001). Sixty-seven per cent of the patients improved their scores, versus 17% and 16% who showed worsening or no change at all in IIEF scores following surgery, respectively. Of the 5 sexual function domains, desire and sexual satisfaction presented statistically significant improvement. CONCLUSION: This study showed that vasectomy caused a positive impact on sexual function, especially on desire and sexual satisfaction, in the majority of men undergoing surgery. There was no case of surgery-related erectile dysfunction.

Adult↗

PubMed1995

No effect of dietary fish oil on renal hemodynamics, tubular function, and renal functional reserve in long-term renal transplant recipients.

Dietary supplementation with fish oil rich in n-3 polyunsaturated fatty acids has been suggested to protect the kidney against cyclosporin A (CsA) toxicity. This study investigated the effects of a 10-wk dietary supplementation with fish oil on renal function and renal functional reserve in healthy volunteers (N = 9) and two groups of stable long-term kidney-transplanted patients treated with maintenance low-dose CsA (3.0 +/- 0.6 mg/kg; N = 9) or without CsA (N = 9). After an overnight fast, the subjects were water loaded, and clearance studies were performed, postponing morning medication. GFR and effective RPF were measured as the renal clearances of (99mTc)DTPA and (131I)hippuran, respectively. Renal tubular function was evaluated by use of the renal clearance of lithium and the urinary excretion of beta 2-microglobulin. Fish oil did not change baseline values of effective RPF, GFR, lithium clearance, and urinary excretion of beta 2-microglobulin in any of the groups. The infusion of amino acids induced a comparable increase in GFR, lithium clearance, and the urinary excretion rate of beta 2-microglobulin in all three groups with no additional effect of fish oil. Thus, long-term renal transplant recipients treated with a low maintenance dose of CsA had a well-preserved renal functional reserve, and dietary supplementation with fish oil in these patients did not improve renal function.

Adult↗

PubMed2003

A functioning profile of Medicaid Waiver participants in Michigan: does the program admit the high functioning?

Michigan's home and community-based Medicaid Waiver program (MIChoice) has been criticized for enrolling people who are relatively high functioning. This study examined the physical and cognitive function of a 2000-2001 cohort of MIChoice enrollees and found that about 10% can be considered high functioning, 32% medium functioning, and 58% low functioning. Much of the controversy over MIChoice can be traced to contradictions inherent in the payment system and the fundamental premise that drives the program.

Activities of Daily Living↗

PubMed1998

Establishing discriminative control of responding using functional and alternative reinforcers during functional communication training.

Functional communication training (FCT) is a popular treatment for problem behaviors, but its effectiveness may be compromised when the client emits the target communication response and reinforcement is either delayed or denied. In the current investigation, we trained 2 individuals to emit different communication responses to request (a) the reinforcer for destructive behavior in a given situation (e.g., contingent attention in the attention condition of a functional analysis) and (b) an alternative reinforcer (e.g., toys in the attention condition of a functional analysis). Next, we taught the participants to request each reinforcer in the presence of a different discriminative stimulus (SD). Then, we evaluated the effects of differential reinforcement of communication (DRC) using the functional and alternative reinforcers and correlated SDs, with and without extinction of destructive behavior. During all applications, DRC (in combination with SDs that signaled available reinforcers) rapidly reduced destructive behavior to low levels regardless of whether the functional reinforcer or an alternative reinforcer was available or whether reinforcement for destructive behavior was discontinued (i.e., extinction).

Adolescent↗

PubMed2003

Immediate functional and non-functional loading of dental implants: a 2- to 60-month follow-up study of 646 titanium implants.

BACKGROUND: The aim of this study was the evaluation, from a clinical point of view, of implants subjected to immediate functional loading (IFL) and to immediate non-functional loading (INFL) in various anatomical configurations. METHODS: The study included 152 patients who had given their informed consent. A total of 646 implants were inserted. The implants were placed in 39 totally edentulous mandibles, 14 edentulous maxillae, 23 edentulous posterior mandibles, 16 edentulous anterior mandibles, 16 edentulous anterior maxillae, and 15 edentulous posterior maxillae. Fifty-eight implants were used to replace single missing teeth. In 65 cases, IFL was carried out for 422 implants. INFL was carried out in 116 cases, (224 implants). RESULTS: In the IFL group 6 of 422 implants failed (1.4%); in the INFL group 2 of 224 implants failed (0.9%). All the other implants appeared, from clinical and radiographic observations, to have successfully osseointegrated and have been functioning satisfactorily since insertion. All failures were observed in the first few months after implant loading. CONCLUSION: Immediate functional and non-functional loading seems to be a technique that gives satisfactory results in selected cases.

Adolescent↗

PubMed1993

Quantification of the relationship between insulin sensitivity and beta-cell function in human subjects. Evidence for a hyperbolic function.

To determine the relationship between insulin sensitivity and beta-cell function, we quantified the insulin sensitivity index using the minimal model in 93 relatively young, apparently healthy human subjects of varying degrees of obesity (55 male, 38 female; 18-44 yr of age; body mass index 19.5-52.2 kg/m2) and with fasting glucose levels < 6.4 mM. SI was compared with measures of body adiposity and beta-cell function. Although lean individuals showed a wide range of SI, body mass index and SI were related in a curvilinear manner (P < 0.0001) so that on average, an increase in body mass index was associated generally with a lower value for SI. The relationship between the SI and the beta-cell measures was more clearly curvilinear and reciprocal for fasting insulin (P < 0.0001), first-phase insulin response (AIRglucose; P < 0.0001), glucose potentiation slope (n = 56; P < 0.005), and beta-cell secretory capacity (AIRmax; n = 43; P < 0.0001). The curvilinear relationship between SI and the beta-cell measures could not be distinguished from a hyperbola, i.e., SI x beta-cell function = constant. This hyperbolic relationship described the data significantly better than a linear function (P < 0.05). The nature of this relationship is consistent with a regulated feedback loop control system such that for any difference in SI, a proportionate reciprocal difference occurs in insulin levels and responses in subjects with similar carbohydrate tolerance. We conclude that in human subjects with normal glucose tolerance and varying degrees of obesity, beta-cell function varies quantitatively with differences in insulin sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1981

Functional effectiveness of a myo-electric prosthesis compared with a functional split-hook prosthesis: a single subject experiment.

The functional effectiveness of a myo-electric prosthesis with sensory feedback compared with that of a split-hook is described. Thirty independent observations were made on a single subject with a right below-elbow amputation wearing the myo-electric prosthesis and the split-hook prosthesis. Using a first order autoregressive model for making inferences about the two sets of data, the split-hook was found to be functionally better (p less than 0.001) than the myo-electric prosthesis. Functional effectiveness was defined operationally as scores on the Minnesota Rate of Manipulation Placing Test and the Smith Test of Hand Function. No predictions are made regarding the use of either prosthesis for other amputees. However clinical evidence suggested suitability of the myo-electric prosthesis with sensory feedback for some other functional tasks.

Adult↗

PubMed2004

Bladder function after incomplete spinal cord injury in mice: quantifiable outcomes associated with bladder function and efficiency of dehydroepiandrosterone as a therapeutic adjunct.

OBJECT: The authors conducted a study to establish outcomes associated with bladder function in a mouse model of spinal cord injury (SCI) and to assess the sensitivity of these outcomes in determining the efficacy of pharmacological treatments. METHODS: A mouse model of moderate contusive SCI was used. Outcome parameters included physiological, behavioral, and morphological measurements. To test the sensitivity of these outcomes, the authors used a dehydroepiandrosterone (DHEA) treatment that they had previously shown to promote neurological recovery effectively after SCI. A behavioral scale was used to identify the day at which autonomic function of the bladder was recovered. The reduction in the daily volume of urine during the period of functional recovery paralleled this scale. They then determined the day postinjury at which the functional differences between the vehicle- and DHEA-treated mice exhibited the maximal amplitude. Changes were measured in the composition of the extracellular matrix relative to collagen expression in the layer muscularis of the detrusor at this time point. They found that SCI increases the ratio of collagen type III to collagen type I in the detrusor. Moreover, in the DHEA-treated group, this ratio was similar to that demonstrated in sham-operated mice, establishing the sensitivity of this outcome to assess therapeutic benefits to the bladder function. They next examined the relationship between measurements of neurological recovery and controlled voiding by using cluster analysis. CONCLUSIONS: The authors found that early recovery of controlled voiding is predictive of motor recovery.

Animals↗

PubMed1982

Functional assessment in partial hospitalization: clinical and administrative applications and implications after one year's utilization of the Framingham Functional Assessment Scale.

This paper presents the use of functional assessment as one response to the growing need for objective measures of outcome in psychiatric treatment. The Framingham Functional Assessment Scale was developed in 1979 as a functional assessment measure to form the basis of a client-oriented cost-outcome system for Medicaid reimbursement in Massachusetts. Clinical and administrative findings from 1 year's utilization of the scale are presented. Level of functioning (LOF) scores in a sample of 45 clients are analyzed to determine the amount of LOF change that occurred during the course of an intensive, 13-week, day-treatment program. Trends and patterns of LOF change are described. Utilization of functional assessment input/outcome data in administrative decision making is discussed, in light of increasing economic constraints in mental-health programs and concomitant demands for service accountability.

Analysis of Variance↗

PubMed1999

Comparing pupil function with visual function in patients with Leber's hereditary optic neuropathy.

PURPOSE: To compare pupil function with visual function in patients with Leber's hereditary optic neuropathy (LHON) and age-matched normal control subjects. METHODS: Visual function was assessed by measuring the perceptual thresholds at five central locations in the visual field using automated static perimetry. Pupil function was assessed by recording the pupil responses to a standard intensity light stimulus (size equivalent to a Goldmann V target) presented at the same five locations in the visual field. The extent of the pupil afferent defect in LHON patients was quantified by establishing the relationship between stimulus intensity and the size of the pupil response in normal subjects and then interpolating the equivalent luminance deficit in LHON patients from the size of their pupil responses. RESULTS: At all five locations tested, the pupil responses were significantly reduced in amplitude, and the perceptual thresholds were significantly raised in LHON patients compared with normal control subjects. A nonparametric analysis of perceptual and pupil responses to perithreshold stimuli showed that a stimulus that was not perceived was three times more likely to be followed by a pupil response in a LHON patient than in a normal subject (P < 0.001). A quantitative comparison showed that the visual deficits exceeded the pupil deficits by on average 7.5 dB at all tested locations. CONCLUSIONS: Although both visual and pupil function are abnormal in LHON, there appears to be relative sparing of the pupil afferent fibers.

Adult↗