Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “longitudinal”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2002

The role of M2 muscarinic receptor subtypes mediating contraction of the circular and longitudinal smooth muscle of the pig proximal urethra.

PURPOSE: We investigated the characterization of muscarinic receptor subtypes in the female pig urethra. MATERIALS AND METHODS: The affinities of muscarinic antagonists against carbachol responses were calculated in normal and cyclic adenosine monophosphate (cAMP) elevated tissues (contraction with KCl and relaxation with isoprenaline) using longitudinal and transverse strips of urethra. RESULTS: In displacement experiments with 1-quinuclidinyl [phenyl-4-3H] benzilate inhibitory constant (pKi) values of 4-diphenylacetoxyl-N-methyl-piperidine methiodide (DAMP) M3 selective antagonist) and methoctramine (M2 antagonist) indicated the presence of the M2 receptor. In functional studies contraction responses to carbachol were greater in longitudinal than in circular muscle. After cAMP elevation the contraction response increased in circular muscles to the level close to that of longitudinal muscles but did not change significantly in cAMP elevated longitudinal muscle. On normal circular tissues 4-DAMP had high mean affinity (mean apparent pKB value 9.3) but with a Schild slope of less than unity (0.76). Methoctramine competitively antagonized carbachol responses (mean affinity [pA2] value 6.9). On normal longitudinal tissues 4-DAMP and methoctramine competitively antagonized carbachol responses (mean pA2 9.0 and 6.2, respectively). After cAMP elevation in circular tissues mean pA2 values for 4-DAMP (8.7) were significantly lower (p = 0.0015), and those for methoctramine (7.3) were significantly higher (p = 0.0193) than in normal tissues. In longitudinal tissues the mean pA2 value for methoctramine (6.9) was significantly greater than in normal tissues (p <0.0001) but the value for 4-DAMP (8.8) did not alter. CONCLUSIONS: Pig urethra appears to have predominantly M2 muscarinic receptors. Contraction of the normal urethra appears to be predominantly mediated by M2 and M3 receptors in circular muscle but by M3 receptors in longitudinal muscle. After cAMP elevation a contribution to contraction of M2 receptors appeared to be demonstrated in the 2 tissues but the involvement of M2 receptors appeared greater in circular muscle.

Animals↗
PubMed2005

Longitudinal continuity of care is associated with high patient satisfaction with physical therapy.

BACKGROUND AND PURPOSE: Recent literature has suggested that longitudinal continuity (ie, the patient is seen by the same practitioner for the entire course of treatment) may be linked to high degrees of patient satisfaction with medical care. The purpose of this study was to provide preliminary information regarding the association between longitudinal continuity and reports of patient satisfaction with physical therapy outpatient care. SUBJECTS AND METHODS: A sample of 1,502 adult subjects completed the MedRisk Instrument for Measuring Patient Satisfaction With Physical Therapy Care at the time of discharge from outpatient physical therapy. Relationships between satisfaction measures and the presence or absence of longitudinal continuity were assessed by use of binary logistic regression. RESULTS: Overall, 36.8% of the subjects reported complete satisfaction on the internal subscale (patient-therapist), and 47.9% of the subjects reported complete satisfaction on the external subscale (patient-support staff). Higher percentages of women (40.2% and 51.1% for internal and external subscales, respectively) than of men (31.9% and 43.3% for internal and external subscales, respectively) were completely satisfied with care. Of subjects who reported complete satisfaction on the internal subscale, 71.2% had longitudinal continuity of care, and 28.8% did not. A similar trend was noted for the external subscale (patient-support staff); 66.8% of subjects who reported complete satisfaction had longitudinal continuity, and 33.2% did not. Odds ratios describing the probability of complete satisfaction with care for subjects who had longitudinal continuity and for those who did not were significant and ranged from 2.7 to 3.5. DISCUSSION AND CONCLUSION: Subjects who received their entire course of outpatient physical therapy from only 1 provider were approximately 3 times more likely to report complete satisfaction with care than those who received care from more than 1 provider. These findings suggest that clinicians and managers should make efforts to preserve longitudinal continuity of care as a means of improving patient satisfaction with care.

Adult↗
PubMed1997

Orthotopic ossification of the spinal ligaments of Zucker fatty rats: a possible animal model for ossification of the human posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament is a human genetic disease in which pathological ectopic ossification of the spinal ligaments develops. This leads to myelopathy or radiculopathy due to compression of the spinal cord. In this study, we investigated the histological features of orthotopic ossification of the spinal ligaments of senile Zucker fatty rats. A remarkably high incidence of orthotopic ossification was observed mainly in the thoracic spinal ligaments as compared with controls. The histopathological findings were similar to those for ossification of the human posterior longitudinal ligament. Bone morphogenetic proteins and activins, which exert their effects by way of specific type-I and type-II serine/threonine kinase receptors, play important roles in the formation of bone and cartilage. In the spinal ligaments of Zucker fatty rats, bone morphogenetic protein receptors and activin receptors were immunohistochemically detected around the ossified foci in a manner similar to that previously shown for the ossified tissue from patients who had ossification of the posterior longitudinal ligament. Thus, bone morphogenetic proteins and activin receptors might play important roles in orthotopic ossification of the spinal ligaments of Zucker fatty rats as well as in ossification of the posterior longitudinal ligament of humans. In addition, bone morphogenetic protein-receptor-IA was expressed in the nonossified ligament, suggesting that the spinal ligaments, of the rats may have a predisposition to orthotopic ossification. In the controls, no expression of bone morphogenetic protein receptors or of activin receptors was observed. In conclusion, there is a great degree of similarity between orthotopic ossification of the spinal ligaments of Zucker fatty rats and ossification of the posterior longitudinal ligament of humans. Thus, the rats provide a useful animal model for the study of ossification of the human posterior longitudinal ligament.

Activin Receptors↗
PubMed1997

Long-term follow-up study of anterior decompression and fusion for thoracic myelopathy resulting from ossification of the posterior longitudinal ligament.

STUDY DESIGN: This was a retrospective study of the results of anterior decompression and fusion in patients with thoracic myelopathy secondary to ossification of the posterior longitudinal ligament with a minimum follow-up time of 5 years. OBJECTIVES: To clarify the effectiveness and limits of anterior decompression and fusion for thoracic ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Posterior decompression for the surgical management of thoracic ossification of the posterior longitudinal ligament has had an uncertain success record. Anterior decompression and fusion have been considered the treatment of choice however, there are few reports describing the long-term results. METHODS: The participants in this investigation were 33 patients whose cases were followed for an average period of 8 years and 2 months. The factors that were investigated included changes in the Japanese Orthopedic Association score and in recovery rates, postoperative complications, and radiographic findings of bone union and progression of ossification of the posterior longitudinal ligament within the area of anterior decompression. RESULTS: Although the recovery rates were relatively stable from 1-5 years after surgery, the rates declined thereafter. The average recovery rate at the final follow-up visit was 53.2%. Postoperative complications included three cases of deterioration of thoracic myelopathy and four cases of extrapleural cerebrospinal fluid leakage. Except for the one case of deterioration of thoracic myelopathy, the remainder of the complications were transient. CONCLUSIONS: Anterior decompression and fusion is an effective surgical procedure for thoracic ossification of the posterior longitudinal ligament with good, stable, long-term results; when thoracic ossification of the posterior longitudinal ligament was extensive or coincident with ossification of the intraspinal ligament, however, the results were not as predictable.

Adult↗
PubMed1994

Longitudinal changes in IQ among fragile X females: a preliminary multicenter analysis.

Longitudinal declines in IQ among fragile X [fra(X)] males have been reported previously by several investigators. Remarkably little is known about longitudinal changes in IQ scores among fra(X) females. Previously, one cross-sectional study showed a significant negative correlation between age and IQ scores. However, a recent investigation of girls with fra(X) syndrome noted longitudinal increases in IQ scores in 8 of 11 individuals. Therefore, the purpose of this preliminary multicenter study was to determine: (1) the characteristics of longitudinal changes in IQ among fra(X) females; and (2) whether these changes were comparable to those which have been observed among fra(X) males. IQ test and retest scores for 11 fra(X) females were obtained from 3 centers: Greenwood, South Carolina; Ibaraki, Japan; and Leuven, Belgium. To ensure high reliability, only test-retest scores from the Wechsler and Stanford-Binet tests were used. Age of subjects at initial testing ranged from 5 to 35 years. Mean intertest interval was 4.5 years. In contrast to a report of longitudinal increases, we found 9/11 (82%) subjects demonstrated decreases in IQ scores. Mean decline was 9 points. Females over 18 years of age showed little or no change in IQ scores. Decreases in scores appeared to be related to initial IQ score. Females in the earlier longitudinal report were higher functioning than those in our study, which may account for the observed difference in direction of change; or, change in IQ score may be related to size of the fra(X) mutation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2004

The relationship between disease activity and radiologic progression in patients with rheumatoid arthritis: a longitudinal analysis.

OBJECTIVE: Radiologic progression in rheumatoid arthritis (RA) is considered the consequence of persistent inflammatory activity. To determine whether a change in disease activity is related to a change in radiologic progression in individual patients, we investigated the longitudinal relationship between inflammatory disease activity and subsequent radiologic progression. METHODS: The databases of the University Medical Center Nijmegen (UMCN) cohort and the Maastricht Combination Therapy in RA (COBRA) followup study cohort were analyzed. The UMCN cohort included 185 patients with early RA who were followed up for up to 9 years. Patients were assessed every 3 months for disease activity and every 3 years for radiologic damage. The COBRA cohort included 152 patients with early RA who were followed up for up to 6 years. Patients were assessed at least every year for disease activity and every 12 months for radiologic damage. Disease activity was assessed with the Disease Activity Score (DAS) (original DAS in the UMCN cohort, DAS28 in the COBRA cohort). Radiologic damage was measured by the Sharp/van der Heijde score in both cohorts. Data were analyzed with longitudinal regression analysis (generalized estimating equations [GEE]), using autoregression for longitudinal associations and radiologic damage as the dependent variable. Time, time(2) baseline predictors for radiologic progression and their interactions with time, as well as DAS/DAS28 (actual values or interval means and interval SDs of the means) were subsequently modeled as explanatory variables. RESULTS: Data analyzed by GEE showed a decrease in radiologic progression over time (regression coefficient for time(2) -1.0 [95% confidence interval -1.4, -0.6] in the UMCN cohort and -0.4 [95% confidence interval -0.8, 0.0] in the COBRA cohort). After adjustment for time effects and baseline predictors of radiologic progression and their interactions with time, a positive longitudinal relationship was indicated by autoregressive GEE between the mean interval DAS and radiologic progression in the UMCN cohort (regression coefficient 5.4 [95% confidence interval 2.1, 8.6]), and between the DAS28 and radiologic progression in the COBRA cohort (regression coefficient 1.4 [95% confidence interval 0.8, 2.0]). In the UMCN cohort, the SD of the mean interval DAS was independently longitudinally related to the radiologic progression over the same periods (regression coefficient 20.2 [95% confidence interval 7.2, 33.3]). In both cohorts, the longitudinal relationships between (fluctuations in) disease activity and radiologic progression were found selectively in rheumatoid factor (RF)-positive patients. CONCLUSION: Radiologic progression is not linear in individual patients. Fluctuations in disease activity are directly related to changes in radiologic progression, which supports the hypothesis that disease activity causes radiologic damage. This relationship might only exist in RF-positive patients.

Adult↗
PubMed2005

Development and testing of multilevel models for longitudinal craniofacial growth prediction.

INTRODUCTION: The aims of this study were to (1) develop longitudinal growth curves that would allow individual variations to be accurately modeled and (2) use these models to predict craniofacial growth changes in children with varying amounts of longitudinal data available. METHODS: Based on a sample of 159 girls (994 cephalograms) and 128 boys (947 cephalograms), multilevel population models were derived. Polynomial models of the population's growth curve were derived for the measurements MPA, Me-X, Me-theta, Me-Y, and Me-R. Angular and horizontal measures (MPA, Me-X, and Me-theta) were described by simpler, second-order models, and vertical measures (Me-Y and Me-R) were described by more complex, fifth-order models. RESULTS: Decreases in MPA during childhood and increases in Me-theta during adolescence could be explained by the relative contributions of the horizontal (Me-X) and vertical (Me-Y) movements of menton. There was greater anterior movement of menton during childhood and greater inferior movement during the adolescent growth spurt. By using varying numbers of longitudinal cephalograms between 6 and 10 years of age, the models were used to predict subjects' craniofacial growth changes from ages 10 to 15. Based on correlations, root mean squared error, and percent accuracy, individual growth predictions for the various measures were found to be highly accurate on an independent subsample drawn from the larger sample and on an independent validation sample. Correlations between predicted and actual values on the sample used to develop the models ranged from 0.81 to 0.95. Accuracy was best for the measurements that changed the most during the prediction period (Me-Y and Me-R), with accuracies between 83% and 90%. More longitudinal data did not increase the predictive accuracy for all measurements. The models that were least accurate (Me-X, MPA, and Me-theta) showed the greatest improvement in prediction accuracy with more longitudinal data. These improvements ranged from 1.6% to 15%. CONCLUSIONS: Longitudinal growth curves based on multilevel procedures can accurately describe population and individual growth curves, and 5-year predictions with this method are highly accurate and externally valid.

Adolescent↗
PubMed1999

Longitudinal outcomes in spinal cord injury: aging, secondary conditions, and well-being.

OBJECTIVE: To specify the degree to which current age, duration of injury, and neurologic status affect the frequency of secondary health and psychosocial conditions in persons with long-term spinal cord injury (SCI), using both longitudinal and cross-sectional analysis techniques. DESIGN: Prospective longitudinal examination and data collection involving individuals with SCI studied initially at their 5th, 10th, and 15th anniversaries postinjury, and subsequently 5 years later at their 10th, 15th, and 20th anniversaries postinjury. SETTING: Five Regional Model Spinal Cord Injury Systems. PARTICIPANTS: The 439 individuals who meet the inclusion criteria for the National SCI Database and who are enrolled in a longitudinal study of secondary conditions and SCI. MAIN OUTCOME MEASURES: Physical and psychosocial status at various times postinjury. RESULTS: There are different reports of various conditions when analyzing by neurologic groups, duration of injury, and age. Cross-sectional and longitudinal analyses also demonstrate different patterns of complications. CONCLUSIONS: The longitudinal method, like cross-sectional research, allows for identification of physical and psychosocial changes soon after they occur. Longitudinal research, however, also makes possible the development of predictive models for various long-term outcomes.

Activities of Daily Living↗
PubMed2003

Importance of smoking habits for longitudinal and age-matched changes in body mass index: a cohort study of Swedish men and women.

BACKGROUND: Previous longitudinal studies of smoking and BMI have focused on smoking cessation. The aim of the present study was to disentangle the effects of long-term smoking on longitudinal changes and age-matched BMI differences (time period effects) in a nation-wide Swedish cohort. METHODS: Men and women (n = 4349) ages 18-73 years reported height, weight, and smoking status for a baseline survey in 1980-1981. Eight and 16 years after baseline, follow-up surveys were conducted for 3244 (75%) of the 4349 subjects. Long-term smokers and long-term nonsmokers were compared with respect to longitudinal changes and age-matched BMI differences. RESULTS: For middle-age adults, the longitudinal increases in BMI were smaller among long-term smokers than long-term nonsmokers regardless of gender. Among the elderly, the longitudinal decrease in BMI was greatest among long-term smokers. Among men, age-matched BMI differences between surveys were smaller for long-term smokers than for nonsmokers. Among women, however, age-matched BMI differences were greater for long-term smokers than for nonsmokers. CONCLUSIONS: In middle-age subjects, longitudinal BMI increases are smaller among smokers than nonsmokers. During old age, the BMI of smokers decreases more than that of nonsmokers. Unknown factors related to gender contribute to larger time period effects of smoking in women than in men.

Adult↗
PubMed1999

Age-related changes in intraocular pressure in a large Japanese population: a cross-sectional and longitudinal study.

OBJECTIVE: To assess the influence of aging, blood pressure, and body mass index (BMI) on intraocular pressure (IOP) in a large Japanese population. DESIGN: Cross-sectional and longitudinal study. PARTICIPANTS: The participants in this study were 69,643 Japanese men and women 20 to 79 years of age. They were office workers and their family members who had received annual health examinations from 1989 to 1997. The records of the participants who received health examinations were reviewed retrospectively. Each participant was examined according to a standard protocol, including tonometry with a noncontact tonometer, anthropometric measurements, and blood pressure measurements. The data from the subjects' most recent visit were analyzed cross-sectionally. The data from the 68,998 men and women of the total participants who were born between the 1920s and 1960s were used in longitudinal analysis. TESTING: Tonometric and anthropometric measurements. MAIN OUTCOME MEASURES: Mean values of IOP, systolic blood pressure, diastolic blood pressure, and BMI were determined. The relationship among IOP, age, systolic blood pressure, diastolic blood pressure, and BMI was studied using the multiple linear regression model with cross-sectional analysis. In longitudinal analysis, regression coefficients of IOP against age, systolic blood pressure, diastolic blood pressure, and BMI were calculated using the mixed effect model. RESULTS: The mean (+/-standard deviation) IOP values for men and women were 11.9+/-2.5 and 11.5+/-2.4 mmHg, respectively. In cross-sectional analysis, IOP decreased significantly with age (P < 0.001). However, longitudinal analysis showed that IOP increased significantly with age in both men and women (P < 0.001). Systolic blood pressure and BMI were positively correlated to IOP in both the cross-sectional and longitudinal studies. CONCLUSION: The authors found an inconsistency in the change in IOP against age between cross-sectional and longitudinal analysis. It is suspected that birth cohort differences in ocular characteristics influence IOP in the Japanese population.

Adult↗
PubMed1999

Longitudinal melanonychia in children: a clinical and histopathologic study of 40 cases.

OBJECTIVE: Very little has been published on longitudinal melanonychia in children. Our objective was to determine the nature of melanocytic lesions in pediatric patients with longitudinal or total melanonychia and to look for correlations between clinical and histologic features. METHODS: All patients younger than 16 years of age with longitudinal or total melanonychia who were evaluated at our nail disorder outpatient clinic between September 1993 and September 1996 were included. The clinical and histologic features of the nail condition were determined in each case. RESULTS: Forty patients were included. The final diagnosis was nevus in 19 cases (junctional in 17 cases and compound in 2), lentigo in 12 cases, and functional longitudinal melanonychia in 9. The latter corresponded to a hyperpigmentation caused by melanocytic activation with no increase in the number of melanocytes. None of the patients had melanoma. Appearance within the first year of life, periungual pigmentation, and total melanonychia were consistent features in patients with melanocytic hyperplasia (lentigo or nevus). Early onset of a dark broad lesion in a white patient was typical of melanocytic hyperplasia, although none of these features were pathognomonic. CONCLUSION: Benign melanocytic hyperplasia (lentigo or nevus) was the cause of 77.5% of cases of longitudinal melanonychia in our overall pediatric population and of 85% of cases in the subset of white patients. All the remaining cases of longitudinal melanonychia were the result of melanocytic activation.

Adolescent↗
PubMed1994

Problems and solutions in longitudinal and experimental treatment studies of child psychopathology and delinquency.

This article identifies questions in child psychopathology and delinquency that can best be answered by using longitudinal data and discusses the advantages and problems of longitudinal studies. The article also reviews methodological issues arising in longitudinal research on child psychopathology and proposes solutions to problems. Retrospective and prospective designs are contrasted with the accelerated longitudinal design. It is concluded that more longitudinal studies of child psychopathology including experimental treatment interventions are needed, with repeated data collection from a variety of sources and several years of data before and after the interventions. Such studies, in addition to the traditional longitudinal studies, are likely to improve the understanding of child psychopathology and of factors that influence and reduce serious outcomes for children and adolescents.

Adolescent↗
PubMed1999

Cross-sectional and longitudinal relationships among age, cognition, and processing speed.

Cross-sectional and longitudinal age effects on cognitive function were examined in 302 older adults followed longitudinally. Processing speed was related to cognitive performance at cross-section, and change in speed predicted within-person longitudinal cognitive decline. Statistical control of processing speed greatly reduced cross-sectional age effects but did not attenuate longitudinal aging effects. This difference in processing speed's ability to account for cross-sectional and longitudinal age effects is discussed in the context of theories of cognitive aging and methodological and statistical issues pertaining to the cross-sectional and longitudinal study of cognitive aging.

Age Factors↗
PubMed2001

A comparison of longitudinal changes in aerobic fitness in older endurance athletes and sedentary men.

OBJECTIVES: To compare the longitudinal changes in maximal aerobic capacity (VO2max) in healthy middle aged and older athletes and sedentary men. DESIGN: A cohort study with mean follow-up of 8.7 years (range 4.0-12.8). SETTING: Outpatient research at a tertiary hospital. PARTICIPANTS: Forty-two healthy, middle aged, and older athletes (initial age 64 +/- 1 year) and 47 healthy sedentary men of comparable age recruited for research studies. MEASUREMENTS: VO2max during a maximal treadmill test. RESULTS: At baseline, the cross-sectional rates of decline in VO2max with age (slope) were virtually identical in the athletes and sedentary men (-0.42 versus -0.43 mL x kg(-1) x min(-1) x year(-1)). At follow-up, the VO2max had declined by 11.9 +/- 1.1 mL x kg(-1) x min(-1) (22%) in the athletes, a crude average rate of -1.4 +/- 0.14 mL x kg(-1)x min(-1) x year(-1). By comparison, the VO2max declined by 4.4 +/- 0.6 mL x kg(-1) x min(-1) (14%) in the sedentary men, a crude average rate of change of -0.48 +/- 0.07 mL x kg(-1) x min(-1) x year(-1). Therefore, the observed absolute rate of longitudinal decline in VO2max in the athletes was triple that of the sedentary men (P= .001) and significantly greater than the decline predicted by their baseline cross-sectional data (P= .001). Post hoc analyses of the longitudinal data in the athletes based on the training regimens over the follow-up period demonstrated that the seven individuals who continued to train vigorously ("high training") had no significant decline in VO2max (0.28% change in VO2max per year). By contrast, the VO2max declined by 2.6% per year in the "moderate training" group (N=21), 4.6% per year in the "low training" group (N=13), and 4.7% per year in the two individuals who developed cardiovascular disease. CONCLUSION: The longitudinal decline in VO2max in older male endurance athletes is highly dependent upon the continued magnitude of the training stimulus. The majority of the athletes reduced their training levels over time, resulting in longitudinal reductions in VO2max two to three times as large as those predicted by cross-sectional analyses or those observed longitudinally in their sedentary peers.

Aged↗
PubMed1998

What students say about learning and teaching in longitudinal ambulatory primary care clerkships: a multi-institutional study.

PURPOSE: Ambulatory primary care clerkships have become crucial elements in medical education. Although most such clerkships employ a block-rotation format, an alternative longitudinal approach has been developed. This study examines students' perceptions of learning and instruction occurring during longitudinal ambulatory clerkships. METHOD: Characteristics of longitudinal ambulatory primary care clerkships at five medical schools are described. Responses of 429 medical students to a standardized survey administered at these institutions are analyzed to ascertain perceptions of learning and teaching occurring during longitudinal ambulatory clerkship experiences. RESULTS: Enhancements of interpersonal communication and clinical skills were perceived to be the most positive learning attributes of the longitudinal ambulatory clerkships. No advantage was discerned with respect to disease-pattern recognition or generation of differential diagnoses. While significant inter-institutional variation was present, particularly with respect to instructional format, there was notable agreement regarding several aspects of clerkship-related learning and the adequacy of faculty supervision. CONCLUSION: Students perceived that learning during longitudinal ambulatory clerkships had greater impact on skill enhancement than on attainment of knowledge-related objectives. Sources of variation in student opinion, perceptions of learning as a function of career preference, and correlation of students' perceptions of learning to demonstrable changes in their competence require further investigation.

Ambulatory Care↗
PubMed2002

Evidence for longitudinal ambulatory care rotations: a review of the literature.

PURPOSE: Block ambulatory rotations and longitudinal ambulatory care experiences are now common in U.S. medical schools, but little is known about their efficacy. Through a structured review of the medical literature from 1966 through March 2000, the authors summarize the characteristics of, the evidence for, and the evaluation of longitudinal ambulatory care rotations. METHOD: The authors searched Medline using the terms "outpatients," "continuity of patient care," "ambulatory care," "mentors," "preceptorship," "graduate medical education," "curriculum," and "clinical clerkship" cross-matched to "medical students" and "internship and residency" for literature published from 1966 through March 2000. They narrowed the list to only articles containing empirical outcome data focusing on medical students' experiences in longitudinal ambulatory care rotations. Each study was scored to assess its strengths and weaknesses. RESULTS: Seven articles met the search criteria. The articles identified the benefits of longitudinal ambulatory care experiences, including developing effective patient interactions and understanding chronic diseases. There were little or no differences in the students' overall knowledge acquisition when those with longitudinal experiences were compared with those in block rotations. DISCUSSION: Although longitudinal ambulatory care experiences are now common in medical schools, evidence supporting their widespread implementation is sparse. Few studies employ rigorous methods to evaluate educational outcomes. Research to identify benefits and costs, improve the quality and consistency of the students' experiences, and develop other innovative ways of teaching and learning ambulatory care is needed.

Ambulatory Care↗
PubMed1995

Dually innervating nociceptive networks in the rat lumbar posterior longitudinal ligaments.

STUDY DESIGN: The present study investigated the distribution of sensory and autonomic nerves to the posterior longitudinal ligament of the rat lumbar vertebra. OBJECTIVE: The results were analyzed to provide a new insight into the pathogenesis of low back pain. SUMMARY OF BACKGROUND DATA: Previous studies that have descriptively reported on posterior longitudinal ligament innervation have attributed important roles to the sinuvertebral nerve as an output of nociceptive sensation. Meanwhile, development of immunohistochemistry has made it possible to identify numerous neurotransmitters, and thus various suggested pathophysiologic roles of the nerve fibers in the posterior longitudinal ligament. However, such microscopic identification of the nerve fibers has not been able to reveal comprehensive distributions of the various fibers, which are presumed to be derived from the sinuvertebral nerve. METHODS: Rat posterior longitudinal ligaments of whole thickness was immunohistochemically stained for calcitonin gene-related peptide and tyrosine hydroxylase, which have been considered markers of nociceptive and noradrenergic fibers respectively. Light-microscopic and electron-microscopic observation was reinforced with another experimental study in which resection of the dorsal root ganglia induced characteristic denervation patterns to the rat posterior longitudinal ligament. RESULTS: The present study revealed that the lumbar. PLL was dually innervated by two distinctive systems of nociceptive fibers. One of the systems was polysegmentally innervated and closely associated with autonomic innervation, whereas the other was unisegmentally innervated and not associated with autonomic fibers. CONCLUSION: Pathogenesis of low back pain can be better understood if the presence of the two distinctive nerve systems innervating the posterior longitudinal ligament is taken into account.

Animals↗
PubMed1996

Effects of strain distribution in the intervertebral discs on the progression of ossification of the posterior longitudinal ligaments.

STUDY DESIGN: Strain distribution in the intervertebral discs was evaluated biomechanically using an engineering true strain calculation formula. OBJECTIVES: This study was performed to clarify the involvement of dynamic factors in the progression of ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: In patients with ossification of the posterior longitudinal ligament of the cervical spine, ossification frequently progresses after laminectomy. This suggests the involvement of dynamic factors in the progression of ossification. However, these factors have not yet been clarified. METHODS: The analysis was performed on 101 patients with ossification of the posterior longitudinal ligament by employing dynamic lateral x-ray films of the cervical spine. The x-ray films were digitized and used as computer data for calculating the strain distribution. X-ray films were obtained again 5 years later, and the strain distribution and the presence or absence of progression of ossification were evaluated. RESULTS: The progression of ossification of the posterior longitudinal ligament was highly correlated with abnormal strain distribution in the intervertebral discs. Progression of ossification was frequently observed in areas having disc distortion in tension and extension on the posterior longitudinal ligament. CONCLUSIONS: In this study, the area of progression of ossification corresponded to the area showing uneven strain distribution and resultant concentration of dynamic stress. These results suggest an important role for dynamic factors in the progression of ossification of the posterior longitudinal ligament.

Adult↗