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PubMed1998

Skeletal muscle myosin heavy chains in heart failure: correlation between magnitude of the isozyme shift, exercise capacity, and gas exchange measurements.

BACKGROUND: Patients with congestive heart failure (CHF) have a reduced exercise capacity because of the early appearance of fatigue and dyspnea. Qualitative changes in the skeletal muscle composition and metabolism can be responsible for the origin of symptoms METHODS: We correlated the myosin heavy chain (MHC) composition of the gastrocnemius in 20 patients with different degrees of CHF to NYHA class, diuretic consumption, echocardiographic parameters, and expiratory gases measured during cardiopulmonary exercise testing. MHC composition was determined electrophoretically in skeletal muscle needle microbiopsies and the percent distribution was calculated by densitometry. Maximal cardiopulmonary exercise testing was performed on a treadmill with a modified Naughton protocol. A capnograph was used. RESULTS: There was no correlation between ejection fraction, left ventricular end systolic diameter, left ventricular end diastolic diameter, and MHC composition. We found a significant positive correlation between the percentage of MHC 1 (slow aerobic isoform) and NYHA class (r2 = 0.62, p < 0.0001), peak VO2 (r2 = 0.5, p < 0.0004), ventilatory threshold (VT) (r2 = 0.33, p = 0.008) and O2 pulse (peak VO2/HR) (r2 = 0.40, p = 0.003). There was a negative correlation between both MHC2a (fast oxidative) and MHC2b (fast glycolytic) with peak VO2 (r2 = 0.38, p = 0.004 and r2 = 0.37, p = 0.004, respectively), VT (r2 = 0.2, p = 0.046 and r2 = 0.34, p = 0.007, respectively), and O2 pulse (peak VO2/HR) (r2 = 0.39, p = 0.003 and r2 = 0.23, p = 0.03). NYHA class was also correlated positively with MHC2a and MHC2b (r2 = 0.46, p = 0.001 and r2 = 0.41, p < 0.006, respectively) and negatively with the same clinical and functional parameters. CONCLUSIONS: The correlation between the magnitude of the MHC shift from the slow aerobic to the fast glycolytic and fast oxidative with both functional and objective measurements of exercise capacity (peak VO2, VT, O2 pulse) seem to suggest that changes in skeletal muscle composition may play a determining role in exercise tolerance in patients with CHF.

Aged↗

PubMed2002

Validity of a new disk grading scale for estimating glaucomatous damage: correlation with visual field damage.

PURPOSE: To determine the correlation of a new disk grading system, the disk damage likelihood scale (DDLS), with the visual field damage in patients with glaucoma. DESIGN: Observational case series. METHODS: Charts of 75 patients (150 eyes) with primary open-angle glaucoma (POAG), 41 patients (82 eyes) with low-tension glaucoma (LTG), and 25 patients (50 eyes) with pseudoexfoliative glaucoma (PXFG) were reviewed retrospectively. DDLS stages and vertical disk sizes were recorded. A masked observer staged the Humphrey field analyzer (program 24-2) visual fields using the Hodapp-Parrish-Anderson (HPA) visual field staging system. Mean deviation (MD) and pattern standard deviation (PSD) values were obtained. The correlation of DDLS with the visual field parameters and HPA staging system were evaluated. Findings were assessed by the Pearson and Spearman correlation coefficients. RESULTS: In the 282 eyes studied, the DDLS was strongly correlated with both MD (Pearson r = - 0.695, P <.001) and PSD (Pearson r =.703, P <.001). The HPA visual field staging system was also strongly correlated with the DDLS (Spearman r =.711, P <.001). These relationships continued to be significant when the three diagnostic groups (POAG, LTG, PXFG) were evaluated separately (P <.001) and also for small (< 1.5 mm) and average size (1.5-2.0 mm) disks. Large disks (> 2.0 mm) were not evaluated, because there was an insufficient number of cases. CONCLUSION: DDLS, a new system for estimating glaucomatous disk damage, strongly correlates with the degree of glaucomatous visual field damage.

Adult↗

PubMed1997

Correlation between mean visual field loss and morphometric optic disk variables in the open-angle glaucomas.

PURPOSE: To correlate morphologic changes of the optic disk with mean visual field defect in glaucoma. METHODS: Color optic disk photographs of 302 patients with primary open-angle glaucoma, 53 patients with pseudoexfoliative glaucoma, and 55 patients with normal-pressure glaucoma were morphometrically evaluated. The data were correlated with mean visual field defect. RESULTS: The correlation between mean visual field defect and neuroretinal rim area was similar to a logarithmic function. The visual field deteriorated slightly in the early stage and markedly in the advanced stages of glaucoma. A discrepancy between normal visual field and abnormal optic disk occurred more often in young than in old patients. Neuroretinal rim shape, total rim area, and rim area in the temporal inferior and temporal superior disk sectors correlated best with mean visual field loss. Alpha and beta zones of peripapillary atrophy and diameter of retinal arterioles were less clearly correlated. Calculated rim variables that were corrected for optic disk area did not markedly improve the correlation coefficients. In eyes with normal visual fields, rim shape was the most important disk variable for detecting glaucomatous optic nerve damage. There were no patients with glaucomatous visual field loss and an unremarkable optic disk. CONCLUSIONS: In early glaucoma, changes are more marked in optic disk appearance than in the visual field, suggesting that at least for some patients, for early glaucoma diagnosis, optic disk appearance is more important than perimetry, whereas for follow-up examination, perimetry may be more useful than optic disk morphometry. The most useful planimetric optic disk parameters are neuroretinal rim shape and rim area.

Adult↗

PubMed1998

Functional changes in back muscle activity correlate with pain intensity and prediction of low back pain during pregnancy.

OBJECTIVE: To assess low back pain (LBP) intensity and subjective disability during pregnancy and compare the pain scores with lumbar motion patterns. DESIGN: A prospective study of pregnant back pain sufferers and healthy controls. SETTING: Kuopio University Hospital, Kuopio, Finland. PARTICIPANTS: Study group consisted of 32 pregnant women with LBP; control group consisted of 21 healthy pregnant women. MAIN OUTCOME MEASURES: Back pain intensity was assessed by visual analog scale (VAS), and subjective disability index was measured by Oswestry Low Back Disability Questionnaire, at 20 and 36 weeks of pregnancy. Back muscle activities were recorded by surface electromyography, and movement sensors were used to detect lumbar motion. RESULTS: In the study group current pain scores (VAS) at first and last trimester correlated strongly (r = .82, p < .00). Pain scores correlated with body weight at the first trimester (r = .54, p = .003) and at the last trimester (r = .67, p < .00). Significant correlation was noted between current pain intensity and back muscle activity level during forward body flexion at first trimester (r = .704, p < .00). Back muscle activity during bending measured at first trimester significantly correlated with pain intensity at last trimester (r = .703, p < .00). Back muscle activity during the first trimester of pregnancy had a negative correlation with current (r = -.57, p = .002) and later subjective disability index (r = -.42, p = .02). It correlated inversely (r = -.54, p = .003) with pain score at last trimester of pregnancy, ie, the lower the back muscle activity at the beginning of pregnancy, the more pain and disability throughout pregnancy. In the control group, three women developed LBP and disability feelings during pregnancy. They had increased muscle activity during flexion at delivery, ie, disturbed flexion relaxation. CONCLUSIONS: Prepregnancy LBP predicts renewed pain during pregnancy, and dysfunction of back muscles has been established in LBP. In this study, disturbance in the relaxation of the back muscles was linearly related to current, and also to later, pain scores. In addition, back muscle activity level was inversely related to the disability index. For the first time, it has been shown prospectively that the function pattern of back extensors seems to predict, and is related to, future back pain. Simple function testing is promising and might be valuable in identifying mothers with a high risk of pregnancy-related back pain and in directing preventive intervention to high risk women by making them aware of self-treatment methods.

Activities of Daily Living↗

PubMed2001

Amphetamine-induced dopamine release in human ventral striatum correlates with euphoria.

BACKGROUND: Studies in experimental animals have implicated the mesolimbic dopaminergic projections into the ventral striatum in the neural processes underlying behavioral reinforcement and motivated behavior; however, understanding the relationship between subjective emotional experience and ventral striatal dopamine (DA) release has awaited human studies. Using positron emission tomography (PET), we correlated the change in endogenous dopamine concentrations following dextroamphetamine (AMPH) administration with the associated hedonic response in human subjects and compared the strength of this correlation across striatal subregions. METHODS: We obtained PET measures of [(11)C]raclopride specific binding to DA D2/D3 receptors before and after AMPH injection (0.3 mg/kg IV) in seven healthy subjects. The change in [(11)C]raclopride binding potential (DeltaBP) induced by AMPH pretreatment and the correlation between DeltaBP and the euphoric response to AMPH were compared between the anteroventral striatum (AVS; comprised of accumbens area, ventromedial caudate, and anteroventral putamen) and the dorsal caudate (DCA) using an MRI-based region of interest analysis of the PET data. RESULTS: The mean DeltaBP was greater in the AVS than in the DCA (p <.05). The AMPH-induced changes in euphoria analog scale scores correlated inversely with DeltaBP in the AVS (r = -.95; p <.001), but not in the DCA (r =.30, ns). Post hoc assessments showed that changes in tension-anxiety ratings correlated positively with DeltaBP in the AVS (r =.80; p [uncorrected] <.05) and that similar relationships may exist between DeltaBP and emotion ratings in the ventral putamen (as were found in the AVS). CONCLUSIONS: The preferential sensitivity of the ventral striatum to the DA releasing effects of AMPH previously demonstrated in experimental animals extends to humans. The magnitude of ventral striatal DA release correlates positively with the hedonic response to AMPH.

Adult↗

PubMed2004

Neuroimaging correlates of anxiety after pediatric traumatic brain injury.

BACKGROUND: Anxiety disorders are common after traumatic brain injury (TBI). Data on the neural correlates of these conditions are lacking. This study examines the relationship between brain damage, particularly to the orbitofrontal cortex (OFC) and temporal lobe, and anxiety symptoms and disorders. METHODS: Ninety-five children and adolescents were followed for one year postinjury. Preinjury and one-year postinjury anxiety status were obtained from the parent. Magnetic resonance imaging was performed to evaluate brain lesions. The primary analysis used regression models to determine relationships between brain lesions and anxiety outcomes. As a secondary analysis, previously reported posttraumatic stress disorder (PTSD) data were reanalyzed using similar methods for purposes of comparison. RESULTS: The primary analysis showed that greater volume and number of OFC lesions correlated with decreased risk for anxiety, whereas lesions in other brain areas did not correlate with anxiety. Consistent with prior data, the secondary analysis showed an inverse correlation between OFC damage and PTSD; temporal lobe damage was positively correlated with PTSD. CONCLUSIONS: After pediatric TBI, greater damage to the OFC is associated with decreased risk for anxiety outcomes. Similar to adult data, these findings implicate OFC dysfunction in childhood anxiety. Temporal lobe damage did not correlate with anxiety, in contrast to the findings for PTSD.

Adolescent↗

PubMed2002

Analysis of coupled bimolecular reaction kinetics and diffusion by two-color fluorescence correlation spectroscopy: enhanced resolution of kinetics by resonance energy transfer.

In two-color fluorescence correlation spectroscopy (TCFCS), the fluorescence intensities of two fluorescently-labeled species are cross-correlated over time and can be used to identify static and dynamic interactions. Generally, fluorophore labels are chosen that do not undergo Förster resonance energy transfer (FRET). Here, a general TCFCS theory is presented that accounts for the possibility of FRET between reactants in the reversible bimolecular reaction, [reaction: see text] where k(f) and k(b) are forward and reverse rate constants, respectively (dissociation constant K(d) = k(b)/k(f)). Using this theory, we systematically investigated the influence on the correlation function of FRET, reaction rates, reactant concentrations, diffusion, and component visibility. For reactants of comparable size and an energy-transfer efficiency of approximately 90%, experimentally measurable cross-correlation functions should be sensitive to reaction kinetics for K(d) > 10(-8) M and k(f) >or= approximately 10(7) M(-1)s(-1). Measured auto-correlation functions corresponding to donor and acceptor labels are generally less sensitive to reaction kinetics, although for the acceptor, this sensitivity increases as the visibility of the donor increases relative to the acceptor. In the absence of FRET or a significant hydrodynamic difference between reactant species, there is little effect of reaction kinetics on the shape of auto- and cross-correlation functions. Our results suggest that a subset of biologically relevant association-dissociation kinetics can be measured by TCFCS and that FRET can be advantageous in enhancing these effects.

Biophysical Phenomena↗

PubMed2003

An empirical correlation between secondary structure content and averaged chemical shifts in proteins.

It is shown that the averaged chemical shift (ACS) of a particular nucleus in the protein backbone empirically correlates well to its secondary structure content (SSC). Chemical shift values of more than 200 proteins obtained from the Biological Magnetic Resonance Bank are used to calculate ACS values, and the SSC is estimated from the corresponding three-dimensional coordinates obtained from the Protein Data Bank. ACS values of (1)H(alpha) show the highest correlation to helical and sheet structure content (correlation coefficient of 0.80 and 0.75, respectively); (1)H(N) exhibits less reliability (0.65 for both sheet and helix), whereas such correlations are poor for the heteronuclei. SSC estimated using this correlation shows a good agreement with the conventional chemical shift index-based approach for a set of proteins that only have chemical shift information but no NMR or x-ray determined three-dimensional structure. These results suggest that even chemical shifts averaged over the entire protein retain significant information about the secondary structure. Thus, the correlation between ACS and SSC can be used to estimate secondary structure content and to monitor large-scale secondary structural changes in protein, as in folding studies.

Amino Acid Sequence↗

PubMed1991

Photon correlation spectroscopy of light scattered by eye lenses in in vivo conditions.

The application of photon correlation spectroscopy on mammalian eye lenses in vivo is revisited. It is shown that the use of a short wavelength laser type and a logarithmic correlator improves the signal-to-noise ratio to such an extent that shorter measurement times are possible without impairing the information content of the correlation function. Experimental correlation functions obtained in vivo on a rabbit eye lens, are analyzed with several techniques. The histogram approach is most successful for the determination of the distribution function of relaxation processes in the correlation function and proposes four different populations of components in the lens. This result is comparable to that from in vitro measurements on highly concentrated solutions of alpha-crystallins and of fiber cell cytoplasm, the former proteins being the main scattering components both in vivo and in vitro in the eye lens system. Our results indicate that the application of photon correlation spectroscopy on eye lenses in vivo offers new perspectives to use this technique as a fast, noninvasive tool to study relaxation phenomena in normal and cataractous lenses. The sensitivity of the method allows it to be used as an important analytical technique in the study of prevention and treatment of cataract.

Absorptiometry, Photon↗

PubMed1995

Protein sequence randomness and sequence/structure correlations.

We investigated protein sequence/structure correlation by constructing a space of protein sequences, based on methods developed previously for constructing a space of protein structures. The space is constructed by using a representation of the amino acids as vectors of 10 property factors that encode almost all of their physical properties. Each sequence is represented by a distribution of overlapping sequence fragments. A distance between any two sequences can be calculated. By attaching a weight to each factor, intersequence distances can be varied. We optimize the correlation between corresponding distances in the sequence and structure spaces. The optimal correlation between the sequence and structure spaces is significantly better than that which results from correlating randomly generated sequences, having the overall composition of the data base, with the structure space. However, sets of randomly generated sequences, each of which approximates the composition of the real sequence it replaces, produce correlations with the structure space that are as good as that observed for the actual protein sequences. A connection is proposed with previous studies of the protein folding code. It is shown that the most important property factors for the correlation of the sequence and structure spaces are related to helix/bend preference, side chain bulk, and beta-structure preference.

Amino Acid Sequence↗

PubMed1995

Intracellular calcium levels correlate with speed and persistent forward motion in migrating neutrophils.

The relationship between cytosolic free calcium concentration ([Ca2+]i) and human neutrophil motility was studied by video microscopy. Neutrophils stimulated by a uniform concentration of an N-formylated peptide chemoattractant (f-Met-Leu-Phe) were tracked during chemokinetic migration on albumin, fibronectin, and vitronectin. [Ca2+]i buffering with quin2 resulted in significant decreases in mean speed on albumin. To further characterize the relationship between [Ca2+]i changes and motility we carried out a cross-correlation analysis of [Ca2+]i with several motility parameters. Cross-correlations between [Ca2+]i and each cell's speed, angle changes, turn strength, and persistent forward motion revealed (i) a positive correlation between [Ca2+]i and cell speed (p < 0.05), (ii) no significant correlation between turns and calcium spikes, and (iii) the occurrence of turns during periods of low speed. Significant negative correlations between [Ca2+]i and angle change were noted on the high adhesion substrates vitronectin and fibronectin but not on the low adhesion substrate albumin. These data imply that there is a general temporal relationship between [Ca2+]i, speed, and persistent motion. However, the correlations are not sufficiently strong to imply that changes in [Ca2+]i are required proximal signals for velocity changes.

Biophysical Phenomena↗

PubMed1992

Auto- and cross-correlation analysis of subthalamic nucleus neuronal activity in neostriatal- and globus pallidal-lesioned rats.

Statistical analyses (autocorrelation and first-order interstimulus interval) were conducted on the spontaneous activity of over 420 subthalamic neurons recorded in 5 groups (control, large globus pallidus kainic acid lesion, partial globus pallidus kainic acid lesion, partial globus pallidus ibotenic acid lesion and neostriatal lesion) of anesthetized rats. Cross-correlation and peristimulus time histogram (to frontal motor cortex stimulation at 0.7 mA) analyses were conducted on pairs (n = 58) of subthalamic neurons recorded simultaneously on a single microelectrode. Lesion of the globus pallidus increased spontaneous firing rate as compared to controls and shifted the pattern of spontaneous activity from either a regular or irregular pattern to a markedly bursting pattern. Neostriatal lesion reduced firing rate and reduced the likelihood of highly regular firing. In control, neostriatal and partial lesioned animals, approximately 1 in 3 pairs of neurons showed correlated firing. The correlations were joint increased probabilities of firing over intervals of 200-400 ms, suggesting a shared excitatory input. No short-interval (less than 10 ms) correlations were seen. Large globus pallidus lesion increased the likelihood of correlated firing (12 of 16 pairs). In all groups of animals the peristimulus time histograms (PSTHs) to motor cortex stimulation were more similar than would be expected by chance and pairs of neurons showed the same increases in response following globus pallidus lesion. Thus adjacent neurons share common cortical inputs and responsiveness to those inputs. These changes indicate that the globus pallidus influences the spontaneous firing rate and pattern of subthalamic neurons as well as the degree of correlated firing of adjacent neurons.

Action Potentials↗

PubMed1997

Neurons of the rostral para-ambiguual field have activity correlated to the 10-Hz rhythm in sympathetic nerve discharge of urethane-anesthetized cat.

Using the techniques of time domain correlation (mid-signal spike-triggered averaging) and frequency domain correlation (neuron-to-nerve coherence), 24% (54) of a sample of 229 neurons of the rostral para-ambiguual field have shown to have activity correlated to the 8- to 13-Hz rhythm in the inferior cardiac sympathetic nerve discharge (SND) of urethane-anesthetized cat. This correlation existed in both baroreceptor-innervated and -denervated animals. Of the correlated neurons, 37% (20) were non-rhythmically firing and displayed flat autospectra, while 63% (34) fired rhythmically and contained well-defined peaks in their autospectra. The group firing rate of these neurons was 4.3 +/- 0.4 spikes/s, indicating that they are not pacemaker neurons for the 10-Hz SND rhythm. The group time of firing of these neurons to the next peak of the SND slow wave was 52 +/- 4 ms. Correlation of the activity of medullary neurons with the 8-13-Hz rhythm of the SND was previously claimed only for rostral ventrolateral medulla, caudal raphe, and rostral caudal ventrolateral medulla. This present finding suggests that this behavior may be more widely spread throughout the medulla.

Anesthetics, Intravenous↗

PubMed2003

Testosterone levels in pregnant women correlate with the insulin response during the glucose tolerance test.

OBJECTIVE: To evaluate the association between insulin/insulin-like growth factor I (IGF-I) systems and androgen levels in pregnancy. DESIGN: Prospective cohort study. SETTING: Yale University School of Medicine. PATIENT(S): Pregnant women undergoing a 100-gram 3-hour glucose tolerance test (GTT). INTERVENTION(S): Serum samples collected during GTT were analyzed for insulin, androgens, free IGF-I, insulin-like growth factor-binding protein (IGFBP) 1, and estriol. MAIN OUTCOME MEASURE(S): Observing the relationship between insulin/IGFs and androgen levels. RESULT(S): The insulin area under the curve (I(AUC)) during GTT correlated positively with total T and free T, but not with dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), or estriol. The peak insulin values (I(max)) during GTT also correlated positively with total T and free T, but not with DHEA, DHEAS, or estriol. There was no statistically significant correlation of T levels with free IGF-I, IGFBP-1, glucose, DHEAS, or estriol. Multiple linear regression analysis modeling showed that I(AUC) and I(max) did have a statistically significant correlation with free T levels. CONCLUSION(S): This study demonstrates for the first time that I(AUC) and I(max) measured in hyperinsulinemic states such as pregnancy correlate with T levels. In view of the lack of correlation between insulin and DHEAS or estriol, insulin-related T production during pregnancy is likely of ovarian origin.

Adult↗

PubMed1986

Measurements of 3 alpha,17 beta-androstanediol glucuronide in serum and urine and the correlation with skin 5 alpha-reductase activity.

Serum and urinary measurements of 3 alpha,17 beta-androstanediol glucuronide (3 alpha-diol G) reflect peripheral androgen action and have been useful clinically. This study was designed to compare these levels in hirsute women, normal premenopausal and postmenopausal women, and in men and to correlate each measurement with skin 5 alpha-reductase activity (5 alpha-RA), an excellent correlate of androgenicity. Although serum 3 alpha-diol G values were similar in premenopausal and postmenopausal women, values were higher in hirsute women and in men. This pattern was similar for urinary 3 alpha-diol G but with greater overlap in values between hirsute and nonhirsute women and men. Serum 3 alpha-diol G showed a highly significant correlation with levels of genital 5 alpha-RA (r = 0.839, P less than 0.001), whereas urinary 3 alpha-diol G did not correlate. Serum and urinary 3 alpha-diol G also did not correlate with one another (r = 0.03). These data suggest that while both serum and urinary 3 alpha-diol G may be useful clinically, serum 3 alpha-diol G appears to correlate better with androgenicity and 5 alpha-RA. It is suggested further that the sources of serum and urinary 3 alpha-diol G may be somewhat different.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed1997

Correlation between endometriosis-associated dysmenorrhea and the presence of typical or atypical lesions.

OBJECTIVE: To evaluate the correlation between the severity of endometriosis-associated dysmenorrhea and the extent of the disease assessed both with a current classification system and with the number and type of endometriosis lesions. DESIGN: Prospective, blinded study. SETTING: Tertiary care, university hospital. PATIENT(S): Sixty-five consecutive patients with endometriosis diagnosed at laparoscopy performed for pelvic pain, infertility, or adnexal mass. INTERVENTION(S): The patients were submitted preoperatively to a questionnaire including the assessment of the severity of dysmenorrhea by means of a 10-point linear analog scale. Evaluation of all visible signs of endometriosis at laparoscopy was performed by a surgeon not aware of the patients' symptoms. MAIN OUTCOME MEASURE(S): The correlation between the severity of dysmenorrhea and the total score for endometriosis and the partial scores for superficial, deep, and adhesion disease as assessed with a current classification system was evaluated. The severity of dysmenorrhea was also correlated with the total number of superficial implants and with the number of typical, pigmented versus atypical, nonpigmented lesions. RESULT(S): The linear analog score for dysmenorrhea correlated significantly with the total endometriosis score, the partial score for deep endometriosis, and the partial score for adhesions. There was no correlation between the pain score for dysmenorrhea and the partial score for superficial endometriosis, nor with the total number of endometriosis implants, the number of typical implants, or the number of atypical implants. CONCLUSION(S): The current classification system for endometriosis, devised primarily to formulate a prognosis in infertile patients, correlates significantly with endometriosis-associated dysmenorrhea. The present study does not support the suggested association between atypical implants and the severity of dysmenorrhea.

Adult↗

PubMed1998

Auditory and visual event-related potentials and flash visual evoked potentials in Alzheimer's disease: correlations with Mini-Mental State Examination and Raven's Coloured Progressive Matrices.

We investigated possible correlations among neurophysiological examinations [auditory and visual event-related potentials (A-ERPs, V-ERPs), and flash visual evoked potentials (F-VEPs)] and neuropsychological tests [Mini-Mental State Examination (MMSE) and Raven's Coloured Progressive Matrices (RCPM)] in 15 subjects with probable or possible Alzheimer's disease (AD) according to the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria. The P300 latency of A-ERPs was correlated with the scores of MMSE but not with those of RCPM. The P300 latency of V-ERPs was more significantly correlated with the scores of RCPM than with those of MMSE. The P2 latency of F-VEPs was more significantly correlated with the scores of RCPM than with those of MMSE. The P2 latency of F-VEPs was not correlated with the P300 latency of A-ERPs but was correlated with the P300 latency of V-ERPs. The close relationship among V-ERPs, F-VEPs and RCPM suggests that these examinations at least partly reflect the functions of visual association areas in AD. Furthermore, discrepancy between P300 latency by A-ERPs and V-ERPs suggests that the mechanism responsible for P300 generation is not identical between these two stimulus modalities.

Aged↗

PubMed1997

Leptin--a regulator of islet function?: its plasma levels correlate with glucagon and insulin secretion in healthy women.

It has previously been demonstrated that plasma leptin correlates to body fat content. It has also been demonstrated that in subjects with normal glucose tolerance, circulating leptin correlates to circulating insulin and to insulin secretion and that these relations are independent of body fat. However, whether leptin also covaries with other islet hormones is not known. We therefore studied the relation between plasma levels of leptin and glucagon secretion and circulating pancreatic polypeptide (PP) in healthy humans. Arginine was injected intravenously (5 g) at fasting and at 14 and 28 mmol/L, glucose in 71 postmenopausal women with normal glucose tolerance. In a multivariate analysis controlling for the influence of the body mass index, we found that circulating leptin correlated significantly to fasting insulin (r = .38, P = .002), and to circulating insulin at 14 mmol/L glucose levels (r = .29, P = .0019) and 28 mmol/L glucose (r = .32, P = .009), as well as to the insulin response to arginine at all three glucose levels (r > .30, P < .013). Circulating leptin, independently of the body mass index, also correlated to fasting glucagon (r = .31, P = .012) and to the glucagon response to arginine at all three glucose levels (r > .28, P < .038). In contrast, circulating leptin did not correlate to plasma glucagon at 14 or 28 mmol/L glucose or to plasma levels of PP. We conclude that circulating leptin correlates to the secretory capacity of both glucagon and insulin but not to the reduction of plasma glucagon during hyperglycemia or to PP in a large group of postmenopausal women. This suggests that islet function is related to circulating leptin in humans.

Arginine↗