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PubMed2002

Estimation of longitudinal resolution in optical coherence imaging.

The spectral shape of a source is of prime importance in optical coherence imaging because it determines several aspects of image quality, especially longitudinal resolution. Wide spectral bandwidth, which provides short coherence length, is sought to obtain high-resolution imaging. To estimate longitudinal resolution, the spectral shape of a source is usually assumed to be Gaussian, although the spectra of real sources are typically non-Gaussian. We discuss the limit of this assumption regarding the estimation of longitudinal resolution. To this end, we also investigate how coherence length is related to longitudinal resolution through the evaluation of different definitions of the coherence length. To demonstrate our purpose, the coherence length for several theoretical and real spectral shapes of sources having the same spectral bandwidth and central wavelength is computed. The reliability of coherence length computations toward the estimation of longitudinal resolution is discussed.

Journal Article↗
PubMed2006

Glial and neuronal functions of the Drosophila homolog of the human SWI/SNF gene ATR-X (DATR-X) and the jing zinc-finger gene specify the lateral positioning of longitudinal glia and axons.

Neuronal-glial communication is essential for constructing the orthogonal axon scaffold in the developing Drosophila central nervous system (CNS). Longitudinal glia (LG) guide extending commissural and longitudinal axons while pioneer and commissural neurons maintain glial survival and positioning. However, the transcriptional regulatory mechanisms controlling these processes are not known. Previous studies showed that the midline function of the jing C2H2-type zinc-finger transcription factor was only partially required for axon scaffold formation in the Drosophila CNS. We therefore screened for gain-of-function enhancers of jing gain of function in the eye and identified the Drosophila homolog of the disease gene of human alpha-thalassemia/mental retardation X-linked (ATR-X) as well as other genes with potential roles in gene expression, translation, synaptic transmission, and cell cycle. jing and DATR-X reporter genes are expressed in both CNS neurons and glia, including the LG. Coexpression of jing and DATR-X in embryonic neurons synergistically affects longitudinal connective formation. During embryogenesis, jing and DATR-X have autonomous and nonautonomous roles in the lateral positioning of LG, neurons, and longitudinal axons as shown by cell-specific knockdown of gene expression. jing and DATR-X are also required autonomously for glial survival. jing and DATR-X mutations show synergistic effects during longitudinal axon formation suggesting that they are functionally related. These observations support a model in which downstream gene expression controlled by a potential DATR-X-Jing complex facilitates cellular positioning and axon guidance, ultimately allowing for proper connectivity in the developing Drosophila CNS.

Animals↗
PubMed1976

Comparative investigations of alpha- and beta-effects on the longitudinal and circular muscles of the pregnant rat myometrium.

Comparative effects of noradrenaline (10(-8)-10(-6) g/ml) and isoprenaline (10(-10)-10(-6) g/ml) on electrical and contractile activity were investigated in longitudinal and circular muscle strips of rat myometrium (13-19 days pregnant). When recorded with an intracellular microelectrode, spike potentials of longitudinal muscle discharged spontaneously in bursts. Treatment with either noradrenaline or isoprenaline hyperpolarized the membrane and increased membrane conductance, causing the cessation of spontaneous activity. Slow potential was dominant in the circular muscle, and it became prolonged after treatment with noradrenaline, leading to an increase in tension. Isoprenaline reduced the duration of the slow potential and depressed the contraction. The minimal concentration of isoprenaline needed to suppress the spontaneous activity in circular muscle was much higher than in longitudinal muscle. The excitatory effect of noradrenaline on circular muscle was antagonized by treatment with phentolamine, and the inhibitory effect of catecholamines on both longitudinal and circular muscles by propranolol. alpha-Adrenoceptor appears predominant in circular muscle, while beta-adrenoceptor in longitudinal muscle in rat myometrium during late-pregnancy.

Action Potentials↗
PubMed1978

Electrophysiological comparison between the longitudinal and circular muscles of the rat uterus during the estrous cycle and pregnancy.

The membrane activities of the longitudinal and circular muscles bundle of rat uteri were recorded with a single sucrose gap method, using animals at various stages of the estrous cycle, pregnancy and after ovariectomy. In the longitudinal muscle during estrus, an initial plateau potential was followed by a slow potential. During diestrus and metestrus, an asynchronized action potential composed of plateau and a slow potential were exhibited. The action potential recorded in uteri taken out of an ovariectomized animal or during early pregnancy was similar to that of uteri during diestrus and metestrus. The circular muscle during estrus gave a plateau potential similar to that of the longitudinal muscle. During diestrus, metestrus, early pregnancy and in the ovariectomized uterus, the membrane activity of the circular muscle was decomposed to produced small plateaus. The spike activity took place in the longitudinal muscle after mid-pregnancy. The slow potential was dominant in the circular muscle during mid-pregnancy, while spikes were progressively generated toward term. Those differences of membrane activity between the longitudinal and circular muscle bundles were discussed in relation to the endogenous change in the sex steroid hormones.

Action Potentials↗
PubMed2005

Use of quantitative two-dimensional color tissue Doppler imaging for assessment of left ventricular radial and longitudinal myocardial velocities in dogs.

OBJECTIVE: To determine left ventricular free wall (LVFW) radial and longitudinal myocardial contraction velocities in healthy dogs via quantitative 2-dimensional color tissue Doppler imaging (TDI). ANIMALS: 100 dogs. PROCEDURE: TDI was used by a single trained observer to measure radial and longitudinal myocardial movement in the LVFW. Radial myocardial velocities were recorded in segments in the endocardial and epicardial layers of the LVFW, and longitudinal velocities were recorded in segments at 3 levels (basal, middle, apical) of the LVFW. RESULTS: LVFW velocities were higher in the endocardial layers than in the epicardial layers. Left ventricular free wall velocities were higher in the basal segments than in the middle and apical segments. Radial myocardial velocity gradients, defined as the difference between endocardial and epicardial velocities, were (mean +/- SD) 2.5 +/- 0.8 cm/s, 3.8 +/- 1.5 cm/s, and 2.3 +/- 0.9 cm/s in systole, early diastole, and late diastole, respectively. Longitudinal myocardial velocity gradients, defined as the difference between basal and apical velocities, were 5.9 +/- 2.2 cm/s, 6.9 +/- 2.5 cm/s, and 4.9 +/- 1.7 cm/s in systole, early diastole, and late diastole, respectively. A breed effect was detected for several systolic and diastolic TDI variables. In all segments, systolic velocities were independent of fractional shortening. CONCLUSIONS AND CLINICAL RELEVANCE: LVFW myocardial velocities decreased from the endocardium to the epicardium and from base to apex, thus revealing intramyocardial radial and longitudinal velocity gradients. These indices could enhance conventional echocardiographic analysis of left ventricular function in dogs. Breed-specific reference intervals should be defined.

Age Factors↗
PubMedDate not supplied

Longitudinal forces acting on a knitted polyester arterial prosthesis when implanted as a thoracic aorta substitute in the dog.

The longitudinal forces under which arterial prostheses are held in situ are of great importance. The tension caused by the longitudinal force may be one of the factors involved in the formation of anastomotic false aneurysms. In order to measure the changes in the longitudinal force at both proximal and distal end-to-end anastomoses over different periods of implantation, we devised an experimental study in which the changes in length of a warp-knitted polyester VP1200K (Vascutek Ltd., Inchinnan, Scotland) arterial prosthesis, used as a thoracic aorta substitute in the dog, were recorded photographically at implantation and removal. The longitudinal forces acting at the two sites were then calculated using a linear relationship between the longitudinal force and the changes in length of a virgin prosthesis, which was found experimentally in vitro using a computerized laser calibration system. One-tailed Student's t-test showed no significant difference between the length indicator values at the two anastomotic sites at different periods of implantation except during the 1-month period. Textile analysis of the explanted prostheses and histopathologic observations confirmed this similar behavior at the two anastomotic sites. These observations were contrary to the theoretic prediction regarding the effect of forces applied by drag and tissue ingrowth. Nevertheless, analysis of variance confirmed that there was no difference evident at the two sites between different implantation periods. These observations may explain why the formation of anastomotic false aneurysms is less common at end-to-end anastomoses.

Animals↗
PubMed2005

Effect of indomethacin on electrical field stimulation-induced contractions of isolated transverse and longitudinal rat gastric fundus strips.

AIM: To study the effects of indomethacin on the isolated transverse and longitudinal rat gastric fundus strips. METHODS: The strips were suspended in an organ bath containing oxygenated Krebs solution, and contractile responses to electrical field stimulation were recorded on a physiograph in an isotonic manner after administration of cumulative concentrations of indomethacin. The effects of indomethacin on the strips pretreated with K(ATP) channel modulators, diazoxide and glybenclamide were studied. RESULTS: Treatment of the transverse strips with indomethacin resulted in a concentration-dependent inhibitory response. In longitudinal strips, biphasic responses were seen, which included a stimulatory response at low concentrations of indomethacin, followed by an inhibitory response at higher concentrations. Diazoxide pre-treatment inhibited the stimulatory response of longitudinal strips. Glybenclamide pre-treatment not only blocked inhibitory effect of the low concentrations of indomethacin on transverse strips, but also increased the amplitude of contractions. Moreover, the drug decreased the amplitude of contractions in longitudinal strips. CONCLUSION: Responses of the isolated longitudinal and transverse rat gastric fundus strips to indomethacin are not similar, and are influenced by K(ATP) channel modulators.

Animals↗
PubMed1996

Longitudinal epiphyseal bracket: associated foot deformities with implications for treatment.

The longitudinal epiphyseal bracket is a rare ossification defect of bones of the hands and feet and results in an abnormal epiphysis that is C-shaped, longitudinally oriented, and vertically extends into the diaphysis. The longitudinal epiphyseal bracket may exist as an isolated deformity, but is commonly associated with digital deformities such as polydactyly, duplicated digits, congenital hallux varus, and clinodactyly. Five case histories of children with the longitudinal epiphyseal bracket in different bones of the foot are described with three distinct clinical presentations. The development of the longitudinal epiphyseal bracket and implications for treatment are considered.

Adolescent↗
PubMed2002

Tissue Doppler imaging in hypertrophic cardiomyopathy: impact of intraventricular obstruction on longitudinal left ventricular function.

BACKGROUND: In non-obstructive hypertrophic cardiomyopathy, tissue Doppler imaging of the mitral annulus shows severe systolic and diastolic dysfunction, with marked heterogeneity and asynchrony. In obstructive forms, the complexity of pathophysiological interactions makes conventional echocardiographic functional assessment extremely difficult and complex. OBJECTIVE: To study longitudinal left ventricular function with tissue Doppler imaging in the obstructive forms of hypertrophic cardiomyopathy. METHODS: Twenty-six patients with hypertrophic obstructive cardiomyopathy and 23 patients with the non-obstructive form of the disease, matched by age, were studied with pulsed tissue Doppler imaging of the 4 sides of the mitral annulus (septal, lateral, inferior, anterior) in 4 and 2 chamber views. In each wave (systolic-s, rapid filling-e, atrial contraction-a) we analyzed velocities, time intervals and velocity-time integrals, as well as heterogeneity and asynchrony indexes. Data were compared between the different sides in each group, between groups and with conventional Doppler data. RESULTS: In contrast to the non-obstructive forms, patients with intraventricular obstruction showed: Systolic function: similar velocities and integrals, the relations between the different sides of the annulus usually being preserved; longer isovolumic contraction time, time to peak s and PEP/LVET. Diastolic function: similar rapid filling and e/a velocities and integrals, lower atrial contraction velocity and integral, similar number of sides with e/a higher than or equal to 1 on the lateral and inferior side of the annulus; similar diastolic time intervals, except diastolic time. CONCLUSIONS: This study shows that the presence of dynamic intraventricular obstruction and the loading conditions of obstructive forms of hypertrophic cardiomyopathy do not significantly influence most annular tissue Doppler imaging parameters, showing the relative load independence of the technique. So, in obstructive hypertrophic cardiomyopathy patients: 1--Longitudinal systolic function (velocities) is similar to the non-obstructive forms--longitudinal systolic dysfunction. 2--Longitudinal diastolic function (velocities and time intervals) is similar to the non-obstructive forms--longitudinal diastolic dysfunction. 3--Left atrial dysfunction is more severe than in non-obstructive forms. 4--The inferior and lateral sides of the annulus should be those selected in order to identify pseudonormalization of the transmitral flow.

Aged↗
PubMed2000

[Clinical analysis on 238 cases of longitudinal fracture of posterior teeth]

OBJECTIVE:To investigate the characteristics and clinical features of the longitudinal fractures of posterior teeth and evaluate the therapeutic methods.METHODS:The records of 238 cases with the longitudinal fractures of posterior teeth were analyzed retrospectively. The clinical features were sum med up. Eextractions of teeth were performed in 108 patients, and the conservative therapies in 130.RESULTS:The incidence of longitudinal fractures of posterior teeth was highest in the 30-59 years. The rate between male and female was 4:3. The longitudinal fractures of posterior teeth most occurred in the first molar of the maxilla with endodontic treatment. The follow up peroid was more than 2 years in 83 cases. The success rate was 75/83. CONCLUSION:The longitudinal fractures of posterior teeth can be cured by early fixation, and prevented by avoiding dysfunctional bite, treating subclinical fracture, and using proper methods of treatment of endodontics.

Journal Article↗
PubMed2006

[Clinical trial of rectocele repair with longitudinal incision and transverse suture on the vaginal posterior wall].

OBJECTIVE: To investigate the clinical efficacy of rectocele repair with longitudinal incision and transverse suture on the vaginal posterior wall. METHODS: One hundred and forty-six patients with rectocele were enrolled in our study from August 1999 to August 2003. The patients were randomly divided into two groups, and received traditional repair with longitudinal incision and longitudinal suture (control group, n=74) or repair with longitudinal incision and transverse suture on the vaginal posterior wall (study group, n=72). The efficacy and complications were compared between the two groups. RESULTS: In the study group,only one case (1.4%) had no effect, and the total effective rate was 98.7%. The mean course of treatment was (11.0+/- 1.9) days. Only two cases (2.7%) had postoperative complication. In the control group, 8 cases (11.1%) had no effect, and the total effective rate was 88.9%. The mean course of treatment was (17.4+/- 1.6) days. Twenty-nine cases (40.3%) had postoperative complications. There were significant differences in the efficacy and complications between the two groups (both P< 0.01). CONCLUSION: The refined rectocele repair with longitudinal incision and transverse suture on the vaginal posterior wall has good efficacy with shorter curative period and less complications.

Adult↗
PubMed1990

Effect of bradykinin on opossum esophageal longitudinal smooth muscle: evidence for novel bradykinin receptors.

Bradykinin (BK) produced a concentration-dependent contraction of the longitudinal but not the circular muscle of the opossum esophagus. The pD2 value of BK on the longitudinal muscle was 6.58 +/- 0.06 M. The maximal response of the longitudinal muscle to BK was 44% compared to carbachol. The putative B1 agonist des-Arg9-BK produced contraction of longitudinal muscle but the putative B1 receptor antagonist des-Arg9-[Leu8]-BK (20 and 50 microM) did not modify the responses to BK or des-Arg9-BK. The putative B2 antagonists d-Phe7-BK, Thi5,8-d-Phe7-BK and d-Arg0-Hyp3-Thi5,8-d-Phe7-BK (B6572) were found to be agonists in this tissue. The rank order of potency with respect to Emax obtained from cumulative concentration-response curves was BK greater than Thi5,8-d-Phe7-BK greater than B6572 greater than d-Phe7-BK and pD2 values of these compounds were 6.58 +/- 0.06, 6.30 +/- 0.28, 6.74 +/- 0.08 and 5.05 +/- 0.04 M, respectively. The excitatory effect of BK and Thi5,8-d-Phe7-BK was not modified by tetrodotoxin (1 and 10 microM), atropine (1 microM) or indomethacin (1 and 10 microM), but was significantly (P less than .001) inhibited by nifedipine (1 and 10 microM). Three putative "tissue selective" BK antagonists, d-Phe2,7-BK (B4404), d-Phe7-Hyp8-BK and Phe2-d-Phe7-BK also had an agonistic effect on longitudinal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

HIV infected hospital patients in New York State. The development of longitudinal information from a hospital discharge data system.

Abstracted records of all patients discharged from New York State acute care hospitals from January 1, 1983, through October 1, 1987, containing a diagnosis of HIV infection (N = 36,664) were linked into a longitudinal file of 20,005 patient-specific case histories. A validation study utilizing Medicaid patient-specific discharge information for calendar year 1985 showed that, on the average, each case history of the longitudinal file contained 85% (+/- 5%) of the expected discharges. The number of patients present in the longitudinal file was 10% (+/- 4%)--too large a percentage, due to a failure to link all the discharges to the appropriate case histories. The number of patients with a diagnosis of Pneumocystis carinii pneumonia (PCP) found in the longitudinal file was found to be consistent with the number reported to the New York State AIDS Registry. The longitudinal file appears to be sufficiently accurate and complete to use in evaluating HIV-related acute care in hospitals.

Adolescent↗
PubMed1986

The development of longitudinal patterns in the rabbit cerebellum.

Reconstruction of several AChE series (from day E 18 after conception till after birth and in maturity) demonstrate that reaction products are localized in alternating positive and negative longitudinal strips. Till day E 26 the AChE activity is topographically related to certain Purkinje cell (P-cell) clusters and located around P-cells. At day E 24 till day E 26 AChE activity shirts into the marginal layer. At day E 28 AChE activity is present at the P-cell layer, around P-Cell somata and their dendrites. The longitudinal band pattern is still present at this age. Around birth AChE activity shifts into the granular layer, constituting a longitudinal AChE pattern. The changes in the localization of AChE are first observed in the anterior lobe and occur later in the posterior lobe vermis and hemispheres. At maturity the longitudinal AChE activity has disappeared from the P-cell layer, but a longitudinal pattern remains present in the granular layer of lobules VIII, IX, X. High AChE activity is found in the granular layer of flocculus and paraflocculus. Within the molecular layer AChE positive Golgi-cells can be demonstrated.

Acetylcholinesterase↗
PubMed1994

Longitudinal changes in time domain spirogram indices and their variability.

The purpose of this study was to describe longitudinal changes in time domain spirogram indices and their variability. We therefore measured forced expiratory spirograms of 326 middle-aged male employees in two asbestos-using factories four times over 5 yrs. From the original sample of 326, 225 healthy subjects, who provided reliable results for three or more surveys, were selected for analysis. The mean and standard deviation of transit time and their log-transformed values (MTT, STT, ln(MTT), and ln(STT), respectively), as well as two indices of the estimated time constant distribution (Mu and Sigma, respectively) were analysed using a longitudinal model. The longitudinally estimated annual increase of MTT, STT, ln(MTT), and ln(STT) was about three times larger than the cross-sectional estimate, whilst they were comparable in Mu and Sigma. A highly significant contribution of between-subject variability was found in all indices. This was particularly remarkable in the mean components. The between-subject variability was about eight times larger than the error variance in Mu, and three times in MTT and ln(MTT). We conclude that the longitudinal data of transit time indices should not be compared with cross-sectional reference values, and that the magnitude of error variance of these indices in longitudinal repeated measurements will be rather less than the cross-sectional counterpart reported previously.

Adult↗
PubMed1997

Changes in physical capacity and sensory/psychomotor functions from 75 to 80 years of age and from 80 to 85 years of age--a longitudinal study.

The purpose of the study was to describe the performance of initially 75- and 80-year-old men and women in physical, sensory and psychomotor tests, to analyse longitudinal changes in these measures over a five-year follow-up period, and to ascertain if the performance in these measures is predictive for survival. At baseline, all 75- and 80-year-old men and women living in the town of Jyväskylä (n = 663) were invited to participate in the study. Five years later those who had participated at baseline, survived and were still resident in Jyväskylä (n = 432) were again invited. As expected, a better performance in men than in women was found in tests of maximal walking speed, stair mounting and maximal isometric muscle strength in both age groups. Men also had better performance in psychomotor tests and visual acuity whereas auditory functions and postural balance were on average better in women. In some measures the longitudinal changes in five years were more pronounced than suggested by the cross-sectional comparisons between the 75- and 80-year-olds at baseline (e.g. psychomotor speed). In some others the longitudinal changes were smaller than expected on the basis of the cross-sectional comparisons (e.g. isometric muscle strength). In sensory functions longitudinal changes corresponded well with the results of the cross-sectional comparisons. Poor physical capacity at baseline was a significant predictor of subsequent death during the follow-up among the women but much less among the men. For both sexes a low psychomotor speed at the baseline was indicative of a poor survival. It is concluded that the correspondence of the results obtained in cross-sectional comparisons with longitudinal changes varies from one function to another. This correspondence may also be influenced by mortality which is differentially associated with the physical, sensory and psychomotor functions analysed in the present study.

Aged↗
PubMed2026

Longitudinal functional network connectivity changes across the clinical stages of C9orf72 hexanucleotide repeat expansion carriers.

INTRODUCTION: Intrinsic functional connectivity network abnormalities in C9orf72 hexanucleotide repeat expansion carriers emerge during the asymptomatic phase, yet longitudinal studies remain limited. We examined cross-sectional abnormalities and longitudinal connectivity changes across clinical stages. METHODS: We analyzed task-free functional magnetic resonance imaging (fMRI) and structural MRI data in 36 asymptomatic (aSxC9), 17 prodromal (proC9), and 29 symptomatic (SxC9) carriers, and 107 healthy controls (HCs). Functional networks previously found altered in C9orf72, including salience, sensorimotor, default mode, and medial pulvinar thalamic networks, were examined. Associations between longitudinal connectivity and gray matter decline with baseline neurofilament light chain (NfL) concentrations and symptom severity were assessed. RESULTS: aSxC9 and SxC9 showed longitudinal connectivity changes within specific networks. In aSxC9, connectivity changes correlated with baseline NfL. In proC9 and SxC9, changes in connectivity and gray matter were associated with baseline NfL and symptom severity. DISCUSSION: C9orf72 expansion carriers demonstrate stage-specific network connectivity changes.

Humans↗
PubMed2006

Longitudinal association of sleep-related breathing disorder and depression.

BACKGROUND: Sleep-related breathing disorder (SRBD) and depression have each been independently associated with substantial morbidity, impairment, and disability. The development of clinical strategies for screening and managing depression in patients with SRBD requires elucidation of the association between the 2 conditions. This population-based epidemiological study assesses SRBD as a longitudinal predictor of depression. METHODS: Men (n = 788) and women (n = 620) randomly selected from a working population were evaluated for SRBD by in-laboratory polysomnography and for depression by the Zung depression scale. Results of multiple studies, performed at 4-year intervals, were available for most participants. Sleep-related breathing disorder was characterized by the apnea-hypopnea index (AHI; events per hour) categories: AHI = 0, no SRBD; 0 < AHI < 5, minimal SRBD; 5 < or = AHI < 15, mild SRBD; and AHI > or = 15, moderate or worse SRBD. Depression was defined as a score of 50 or higher on the Zung scale or use of antidepressants. Potential confounding, interacting, and mediating factors were assessed by clinical measurements and questionnaires. RESULTS: In purely longitudinal models, an increase of 1 SRBD category (eg, from minimal to mild SRBD) was associated with a 1.8-fold (95% confidence interval, 1.3-2.6) increased adjusted odds for development of depression. In adjusted models combining longitudinal and cross-sectional associations, compared with participants with no SRBD, the odds for development of depression were increased by 1.6-fold (95% confidence interval, 1.2-2.1) in participants with minimal SRBD, by 2.0-fold (95% confidence interval, 1.4-2.9) in participants with mild SRBD, and by 2.6-fold (95% confidence interval, 1.7-3.9) in those with moderate or worse SRBD. CONCLUSION: Our longitudinal findings of a dose-response association between SRBD and depression provide evidence consistent with a causal link between these conditions and should heighten clinical suspicion of depression in patients with SRBD.

Adult↗