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PubMed1998

The growth of the human embryo. A longitudinal biometric assessment from 7 to 12 weeks of gestation.

OBJECTIVES: Longitudinal studies of multiple parameters in the first trimester for assessment of embryonic growth are lacking. This study's aim was to register changes in growth over time, by taking several measurements of embryos on successive occasions and evaluating these changes by longitudinal analysis. DESIGN: This prospective longitudinal study describes the normal embryonic growth in vivo. Inclusion criteria were non-smoking women with single uneventful pregnancies, regular menstrual periods (28-30 days) and no hormone therapy in the 3 months prior to the pregnancy. Exclusion criteria were pregnancy complications such as diabetes, pre-eclampsia, delivery of preterm or growth-restricted infants. Of 36 recruited pregnant women, 29 met these criteria. Each pregnancy was examined five times between 7 and 12 weeks of gestation. This resulted in a two-level data set, where level 1 consisted of the observations and level 2 consisted of the individuals. The longitudinal data were analyzed with a software package specially created for multilevel analysis. RESULTS: The growth of the biparietal diameter (BPD), occipitofrontal diameter (OFD), mean abdominal diameter (MAD), chorionic cavity diameter and amniotic cavity diameter was constant; the growth of the crown-rump length (CRL) and the yolk sac diameter was not constant. Variation in the data sets was mainly caused by variation between the embryos/fetuses. CONCLUSIONS: The measured parameters except for the yolk sac showed a high degree of uniformity with virtually the same growth velocities. The yolk sac demonstrated uniform growth until week 10 only. Differences between the gestational age based on the last menstrual period and the true gestational age, and/or differences in the early growth of the embryos before the start of the study at 7 weeks, may have contributed to the variation between the individuals.

Adult↗
PubMed1994

Outlier reduction by an option-3 measurement scheme.

Detecting changes in longitudinal data is important in medical research. However, the existence of measurement outliers can cause an unexpected increase in the false alarm rate in claiming changes. To reduce the outliers, a new method has been developed. In this scheme, two measures are initially taken and, if they are closer than a specified threshold, the average of the two is considered to be the estimate of the true mean; otherwise a third measurement is taken, and the mean of the closest pair is considered to be the estimate. It is shown that this method has considerable sample size advantage over naive repeated measurements. Moreover, this scheme is robust for outlier error distribution. Evidence on outlier removal in dental attachment probing is used as an example.

Analysis of Variance↗
PubMed1994

A longitudinal family study of personality change and stability.

The 19-year stability of personality from late adolescence to early adulthood was examined in a sample of 121 men and women who had participated in an earlier study of articulation and language development (Templin, 1966; Templin & Glaman, 1976). Personality was assessed using the Eysenck Personality Inventory (EPI). At the time of retest, personality data were also collected from the participants' mothers. Modest stability of individual differences in personality was observed, consistent with the literature on longitudinal studies of personality during late adolescence and early adulthood. For the Extraversion and Neuroticism scales, offspring means decreased significantly over the 19-year period such that the offspring means were closer to the mean scores of their mothers when they were followed up in adulthood as compared to their first testing in adolescence. There was, however, no change in mother-offspring resemblance from the initial test to retest. Mother-offspring resemblance appears to be due largely to aspects of personality that were stable from adolescence to early adulthood. Implications of these results are discussed in relation to the findings of previous longitudinal studies of adult personality and recent behavioral genetic evidence regarding personality change and stability.

Adolescent↗
PubMed2006

Self-weighing in adolescents: helpful or harmful? Longitudinal associations with body weight changes and disordered eating.

PURPOSE: This study addresses the question: Is frequent self-weighing related to changes in body weight and disordered eating behaviors over a 5-year period among adolescent females and males? METHODS: Project EAT is a 5-year population-based longitudinal study. Participants completed surveys exploring factors associated with eating and weight concerns. Participants included 2516 adolescents who were transitioning from early to middle adolescence (younger cohort) and from middle to late adolescence (older cohort). RESULTS: In the older cohort of females and in both cohorts of males, frequent self-weighing at Time 1 was not associated with weight changes at Time 2 (5 years later), after adjusting for Time 1 weight status and sociodemographic characteristics. In the younger cohort of females, Time 1 frequent self-weighing predicted weight increases at Time 2. In both cohorts of females, but not in males, Time 1 frequent self-weighing predicted higher prevalences of Time 2 disordered eating behaviors, including unhealthy weight control behaviors and binge eating, after adjusting for Time 1 behavioral outcomes, weight status, and sociodemographic characteristics. CONCLUSIONS: Frequent self-weighing was not associated with weight change, with the exception of predicting weight increases in younger females. In females, but not males, self-weighing predicted a higher frequency of binge eating and unhealthy weight control behaviors. Although further research is needed to explore the potential merits and problems associated with regular self-weighing, the findings suggest that population-based obesity prevention strategies targeting adolescents should avoid messages likely to lead to frequent self-weighing.

Adolescent↗
PubMed2001

Changes in hip and ankle range of motion and hip muscle strength in 8-11 year old novice female ballet dancers and controls: a 12 month follow up study.

OBJECTIVES: To evaluate in a 12 month longitudinal study changes in hip and ankle range of motion and hip muscle strength in young female novice ballet dancers. METHODS: Fifty three of the original 77 (69%) female dancers aged 8-11 years and 40 of the original 49 (82%) controls returned for follow up measurements one year later. Supine right active hip external (ER) and internal (IR) rotation were measured using an inclinometer. A turnout protractor was used to assess standing active turnout range. Range of right weight bearing ankle dorsiflexion and calf muscle length were measured in a standing lunge position using an inclinometer. A manual muscle tester was used to assess right hip flexor, IR, ER, abductor and adductor strength. RESULTS: The mean (SD) 12 month change in hip ER did not differ between dancers (11.7 (11.3)degrees) and controls (8.1 (17.6)degrees). Dancers gained 12.5 (13.5)degrees hip IR which was significantly greater than controls (0.5 (13.9)degrees). Greater IR change was associated with improved IR strength (r = 0.34, p<0.001). Dancers increased total turnout (12.0 (16.7)degrees) significantly more than controls (2.2 (20.0)degrees). There was no significant change in ankle dorsiflexion range in either group. Dancers and controls increased in all measures of hip muscle strength (p<0.001) and dancers achieved significantly greater gains in three out of five muscle groups (all, p<0.05). CONCLUSIONS: Total hip range of motion increased in both ballet students and controls at this young age. However, ankle dorsiflexion did not, which is probably due to this movement being blocked by bony apposition, rather than soft tissue stretch. This has implications for ballet teachers, as it has long been accepted that this movement could be improved with training. Dancers had greater increases in hip strength after 12 months compared with controls in muscles specific for ballet, suggesting that hip strength can be trained at this young age. Whether these gains are permanent requires further study.

Analysis of Variance↗
PubMed2000

Socio-demographic variables and 6 year change in body mass index: longitudinal results from the GLOBE study.

BACKGROUND: Body mass index (BMI) differs by socio-demographic variables, but the origin of these associations remains relatively unknown. OBJECTIVE: To investigate the association between socio-demographic variables and the subsequent change in BMI over six years. DESIGN: A Dutch prospective cohort study (GLOBE) from which data were used from initially 20-49-year-old subjects (males: n=362; females: n=405). BMI was calculated from self-reported body height and weight data obtained in 1991 and 1997. Socio-demographic variables used were sex, age, educational level and the occupational level of the main breadwinner, family income, marital status, religious affiliation and degree of urbanization and measured in 1991. RESULTS: Cross-sectionally, BMI was higher in males than in females. BMI was positively associated with age and negatively associated with educational level in both sexes, after adjustment for the other socio-demographic variables. A positive association of BMI with family income was found in males and a negative association with occupational level was found in females. During follow-up, BMI increased significantly more in females (from 23.0 (s.d. 3.3) to 24. 2 (s.d. 3.8)) than in males (from 24.3 (s.d. 2.9) to 25.1 (s.d. 3. 5)). With the exception of a significant lesser increase in BMI in initially 30-39-year-old women compared to initially 40-49-year-old women, no other statistically significant associations were found between socio-demographic variables and the 6-year change in BMI. CONCLUSIONS: Cross-sectional differences in BMI by socio-demographic variables are not due to different 6-year changes in BMI for categories of these variables in adulthood. Cross-sectional differences in BMI by educational level are probably established at the end of adolescence.

Adult↗
PubMed2004

Changes in mechanism of PACAP-induced relaxation in longitudinal muscle of the distal colon of Wistar rats with age.

Mechanisms of relaxation of longitudinal muscle of the distal colon induced by exogenously added pituitary adenylate cyclase activating peptide (PACAP) were studied in 2- to 30-week-old Wistar rats. Exogenous PACAP induced very significant relaxation of the longitudinal muscle in 2-week-old rats, but this effect decreased significantly with age. The cyclic AMP-cyclic AMP-dependent protein kinase (PKA) pathway and the tyrosine kinase-small conductance Ca2+-activated K+ channel (SK channel) pathway were found to be involved in the mechanism of PACAP-induced relaxation. In 2-week-old rats, PACAP-induced relaxation was significantly inhibited by tetrodotoxin (TTX). Since relaxation was also significantly inhibited by NG-nitro-L-arginine (N5-nitro-amidino-L-2,5-diamino-pentanoic acid: L-NOARG), the neurogenic effect of PACAP seems to be mediated mainly through nitric oxide neurons. In 8-week-old rats, L-NOARG and TTX had little effect on PACAP-induced relaxation, suggesting that the relaxant effect in 8-week-old rats is a direct action on longitudinal smooth muscle cells. Changes in the mechanisms of PACAP-induced relaxation with age were examined in the distal colon in relation to changes in the neurogenic and the direct effects of PACAP. The neurogenic effect in the exogenous PACAP-induced relaxation of the longitudinal muscle of the Wistar rat distal colon is dominant in tissue isolated from 2-week-old and lost in tissue isolated from 8-week-old rats.

Age Factors↗
PubMed2004

Noninvasive in vivo determination of intracerebral oxygen concentration in rats by a longitudinally detected ESR (LODESR) technique.

We have developed a noninvasive method to determine oxygen concentration in the brain tissue of rats in vivo. The method is based upon measuring the fundamental harmonic-to-secondary harmonic ratio (FSR) of longitudinal magnetization changes of a blood-brain barrier (BBB)-permeable nitroxide radical, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (hydroxymethyl-PROXYL), by employing a longitudinally detected ESR (LODESR) spectrometer operating at an ESR frequency of 280 MHz. FSRs of phantoms, including a hydroxymethyl-PROXYL solution and various concentrations of oxygen, were measured. We found that the FSRs of the phantom increased as the oxygen concentration increased. In vivo FSRs in the brains of rats that had received a hydroxymethyl-PROXYL injection were measured without the use of any surgical procedures. It was found that when the rats breathed 100% oxygen, rather than normal air, the FSR was significantly greater.

Animals↗
PubMed1996

Vascular dementia: perfusional and metabolic disturbances and effects of therapy.

Positron emission tomography (PET) has elucidated basic pathophysiological mechanism that produce the cognitive decline in vascular dementia (VD). The typical pattern of glucose metabolism seen in VD with scattered areas of focal cortical and subcortical hypometabolism differs from that in AD with marked hypometabolism affecting the association areas. The total volume of metabolically inactive tissue is significantly related to severity of dementia. Rather than the quantity of tissue destruction, the critical effect may be the quantity of cortical hypometabolism caused by subcortically induced disconnection. Studies with HMPAO SPECT have shown focal deficits in VD and AD patients that are comparable to those seen with FDG PET. In mildly demented patients performance for the classification AD versus VD is much better by PET because it might be more sensitive for imaging small functional pathological changes. A longitudinal analysis of rCMRGl in VD showed that the progression of dementia can be delayed by the adenosine uptake blocker propentofylline and that neuropsychological and metabolic changes are closely related.

Brain↗
PubMed2001

Retrospective longitudinal study of visual acuity change in patients with retinitis pigmentosa.

PURPOSE: To determine the extent that clinically evident macular lesions in patients with retinitis pigmentosa (RP) help to establish their prognosis for visual acuity (VA) retention. METHODS: The records of 182 patients with RP were reviewed. The macular lesion status at the initial examination was determined to be no lesion, a bull's-eye atrophic lesion, or a geographic atrophic lesion. Multiple linear regression analysis was used to evaluate the relationship of initial VA, macular lesion type, and RP genetic subtype to predict the VA change per 5-year period. RESULTS: The regression effect of lesion type on the VA change was statistically significant (P < 0.0001). Patients with no macular lesion had a predicted 5-year change of less than 1 line, whereas those with either a bull's-eye or geographic atrophic lesion had a predicted 5-year change of three to four lines. The 5-year changes were not related to a patient's age or level of VA at initial presentation, when controlling for type of macular lesion. CONCLUSION: By examining longitudinal data, the authors found that the presence or absence of a macular lesion at the patient's initial visit was an important determinant of VA loss in this cohort of patients with RP. These findings are of value when counseling patients with RP regarding their prognosis for preservation of VA.

Adolescent↗
PubMed2001

From bedside nursing to managerial roles: changing occupational perceptions of nursing students.

This longitudinal study examined changes in the occupational perceptions of nursing students studying in a non-traditional undergraduate nursing program. The respondents, 210 first- and second-year nursing students, completed a questionnaire measuring the perceived importance of traditional and non-traditional nursing interventions and values. Questionnaires were administered at the beginning and at the end of the academic year. Students studying in a more traditional program comprised the control group. The results show that certain traditional nursing activities and values are perceived as more important by first-year students compared with second-year students in both programs, whereas the perceived importance of non-traditional activities is higher among second-year students. The preference for non-traditional interventions is stronger among students in the non-traditional nursing program. The results are discussed with regard to the gradual effect of nursing education on students' occupational perceptions.

Adult↗
PubMed2004

Endogenous recovery of injured spinal cord: longitudinal in vivo magnetic resonance imaging.

Pathological changes were followed longitudinally with in vivo magnetic resonance imaging (MRI) and behavioral studies in experimental spinal cord injury (SCI). MRI-observed pathology was correlated with histology. On MRI, the cavitated regions of the injured cord were gradually filled with viable tissue between two and 8 weeks postinjury, and a concomitant improvement was observed in the neurobehavioral scores. By weeks 3-6, on MRI, the gray matter (GM) returned in the segments caudal, but not rostral, to the injury site. The corresponding histological sections revealed motor neurons as well as other nuclei in the gray matter immediately caudal to the epicenter, but not at the site of injury, suggesting neuronal recovery in perilesioned areas. The neuronal and neurological recovery appeared to occur about the same time as neovasculature that was reported on the contrast-enhanced MRI, suggesting a role for angiogenesis in recovery from SCI. The role of angiogenesis in neuronal recovery is further supported by the immunohistochemical observation of greater bromodeoxyuridine uptake by blood vessels near the lesion site compared with uninjured cords.

Animals↗
PubMed1990

Blood flow velocity and pulsatile diameter changes in the fetal descending aorta: a longitudinal study.

Blood flow velocity and pulsatile diameter changes in the fetal descending aorta were measured subsequently with pulsed Doppler ultrasonography and phase-locked echo-tracking technique, respectively. Blood flow velocity and pulse-wave curves with equal beat-to-beat intervals were synchronized by external fetal electrocardiogram. The systolic increase in blood flow velocity and in vessel diameter started simultaneously. The velocity peak preceded the diameter peak by a significant margin (p in the range 0.0001 to 0.0014). The time interval was more pronounced in the thoracic than in the abdominal part of the aorta and was slightly smaller near term. The effective diameter, calculated from the synchronized integrals of the blood flow velocity and the diameter curves, was significantly greater (p in the range 0.0001 to 0.0016) than the mean diameter. The difference tended to decrease with advancing gestational age and was more pronounced in the thoracic than in the abdominal aorta. The maximum error incurred by the use of nonsimultaneous measurements of blood flow velocity and vessel diameter when calculating volume blood flow was found to be less than 8% and thus probably of little practical importance.

Aorta, Thoracic↗
PubMed1993

EEG power spectra and cognitive change in geriatric psychiatry: a longitudinal study.

Elderly patients with senile dementia of the Alzheimer type (SDAT), multi-infarct dementia (MID) and functional psychiatric illness, along with elderly control subjects, were studied longitudinally at 6 monthly intervals over a 2 year period, with cognitive testing and EEG power spectral analyses being carried out on each occasion. There was no significant change in the EEG power over time although a significant regression effect was noted for cognitive performance in the SDAT group. A number of between-group differences were apparent. The SDAT patients had more delta and theta power and less alpha power than those with MID and the latter group had a higher percentage of delta and theta power than the functional patients. The functional patients and normal subjects were differentiated from each other by a number of EEG power variables. The implications of these findings with respect to differential diagnosis in geriatric psychiatry are discussed.

Aged↗
PubMedDate not supplied

[Socioeconomic inequalities in health in the Tuscany Longitudinal Study (SLTO): persistence and changes over time in overall mortality and selected causes (lung cancer, liver cirrhosis, AIDS and overdose)].

We evaluate the persistence of social inequalities in overall mortality or mortality by causes (lung cancer, liver cirrhosis; AIDS and overdose) in the Tuscany Longitudinal Study (SLTo), a record linkage-study on the census population identified at the 1981 and 1991 censuses in Leghorn (1981: 175,741 subjects; 1991: 167,512 subjects), and 1991 in Florence (403,294 subjects), Central Italy. The census data allow an evaluation of socio-economic status of each subject, using variables such as education or occupation, or constructing indexes inclusive of deprivation indexes. Follow-up is from the census up to 1995 and for specific causes of death from 1987 (Leghorn) or 1991 (Florence). Estimates of risk are computed comparing rates of mortality among socio-economic groups, by means of poisson regression models, or by means of Standardized Mortality Ratios using the indirect method. The causes of deaths have been selected mainly because explained by known and strong determinants. As far as overall mortality, the results suggest the persistence of gradients by social class, more often negative among males. Mortality from lung cancer has a strong negative social class gradient among males, and a divergent gradient among women in the two towns, which is interpreted as the effect of a different prevalence of smoking by period, social class and sex. High RRs among lower socio-economic groups have been detected for liver cirrhosis mortality. Excess mortality of AIDS and overdose, an expression of the recent drug crisis, concentrates on the lower social strata and in young adults. Whereas mortality from AIDS has been detected among both sexes, deaths from overdose are occurring among males only. Being AIDS and overdose recent diseases, they stress the persistence of social inequalities over time.

Acquired Immunodeficiency Syndrome↗
PubMed2006

A smart magnetic resonance contrast agent for selective copper sensing.

We describe the synthesis and properties of Copper-Gad-1 (CG1), a new type of smart magnetic resonance (MR) sensor for selective detection of copper. CG1 is composed of a gadolinium contrast agent core tethered to copper-selective recognition motif. Cu2+-induced modulation of inner-sphere water access to the Gd3+ center provides a sensing mechanism for reporting Cu2+ levels by reading out changes in longitudinal proton relaxivity values. CG1 features good selectivity for Cu2+ over abundant biological cations and a 41% increase in relaxivity upon Cu2+ binding and is capable of detecting micromolar changes in Cu2+ concentrations in aqueous media.

Contrast Media↗