Biomedical subjects

P Clopton

Publications and source records attributed to P Clopton.

At least 37 records · Page 2Linked to original sources

PubMed1996

Accuracy of contrast-enhanced magnetic resonance angiography in chronic thromboembolic disease.

RATIONALE AND OBJECTIVES: We evaluated the accuracy of contrast-enhanced magnetic resonance (MR) angiography in demonstrating the findings of chronic pulmonary thromboembolism (CPTE) compared with conventional pulmonary angiography. METHODS: We examined 18 patients with CPTE proved by conventional pulmonary angiography and 16 healthy control patients. T1-weighted and single-breathhold, two-dimensional multiplanar spoiled gradient-recalled pulmonary images were obtained after injection of gadopentetate dimeglumine. Images were interpreted independently by two radiologists. RESULTS: All patients with CPTE were identified on MR angiography images by both readers. Sensitivity and specificity for MR angiography in diagnosing abnormal segments were 76% and 95% for reader 1 and 68% and 93% for reader 2, respectively. Sensitivity and specificity for MR angiography in depicting abnormal lobes were 83% and 96% for reader 1 and 82% and 93% for reader 2, respectively. Interobserver agreement was high; kappas for abnormal segments and abnormal lobes were .72 and .84, respectively. The T1-weighted spin-echo images demonstrated a mosaic signal intensity pattern in all patients with CPTE. CONCLUSION: Contrast-enhanced MR angiography accurately depicts abnormal segments and lobes in occlusive vascular disease and clearly distinguishes between patients with CPTE and those with healthy lungs.

Chronic Disease↗

PubMed1996

Imaging of osseous and cartilaginous intraarticular bodies in the knee: comparison of MR imaging and MR arthrography with CT and CT arthrography in cadavers.

PURPOSE: To compare magnetic resonance (MR) imaging and MR arthrography with computed tomography (CT) and CT arthrography in the detection of intraarticular bodies in the knee. MATERIALS AND METHODS: Cuboid (3- or 6-mm-long sides) osseous and cartilaginous bodies were implanted in 16 cadaveric knee specimens. MR imaging was performed with T1-weighted spin-echo (SE), T2-weighted SE, proton-density-weighted SE, gradient recalled acquisition in the steady state (GRASS), and spoiled GRASS sequences. MR arthrography was performed in two phases with saline and 2 mmol/L gadopentetate dimeglumine. CT and CT arthrography were performed in the transaxial plane. RESULTS: MR arthrography yielded the highest accuracy for the detection of osseous and cartilaginous bodies combined (92%) and was significantly (P < .01) better than MR imaging (57%-70%), CT arthrography (80%), and CT (74%). Accuracy of CT arthrography was significantly better than that of MR imaging and that of CT. Accuracy of saline-enhanced MR arthrography was significantly inferior (P < .001) to that of gadolinium-enhanced MR arthrography. CONCLUSION: MR arthrography is the best imaging technique for detection of individual intraarticular bodies. CT arthrography is the second most accurate method. Spoiled GRASS and T2-weighted SE sequences are the most accurate at MR imaging. The presence of intraarticular fluid and performance of saline-enhanced MR arthrography improve detectability of intraarticular bodies.

Arthrography↗

PubMed1996

Calcium pyrophosphate dihydrate crystal deposition disease: frequency of tendon calcification about the knee.

OBJECTIVE: To delineate the prevalence of tendon and cartilage calcification as well as its possible predilection for age, sex, or side of involvement in calcium pyrophosphate dihydrate (CPPD) crystal deposition disease of the knee. METHODS: We reviewed 225 lateral knee radiographs from 138 patients (M/F: 85/52, 1 unspecified sex, mean age: 73 yrs) to document quadriceps and gastrocnemius tendon calcification. Chondrocalcinosis of the knee was evaluated on 275 knee radiographs (lateral and anteroposterior projection) from 153 patients (M/F: 97/55, 1 unspecified sex, mean age: 73 yrs) to determine the frequency of meniscal and hyaline cartilage calcification. RESULTS: Gastrocnemius tendon calcification was found in 28.4% of knees, which is significantly more common than quadriceps tendon calcification (8.4%). No significant age or laterality difference existed for calcification of either tendon. Quadriceps tendon calcification was more prevalent in men, but no sex difference was present for the gastrocnemius tendon. Calcification of either tendon never occurred without associated chondrocalcinosis. Meniscal calcification was significantly more prevalent than hyaline cartilage calcification; meniscal calcification also was significantly more frequent in men. Increased prevalence of calcification with age was observed in hyaline cartilage but not in the menisci. CONCLUSION: Gastrocnemius tendon calcification is not infrequent in CPPD crystal deposition disease of the knee; identification of such calcification may further delineate this extent of the disorder.

Adult↗

PubMed1995

Interpretation of abnormal lumbosacral spine radiographs. A test comparing students, clinicians, radiology residents, and radiologists in medicine and chiropractic.

STUDY DESIGN: Controlled comparison of radiographic interpretive performance based on training and experience. OBJECTIVES: This study compared each of these groups in medicine and chiropractic by testing abilities to interpret abnormal plain film radiographs of the lumbosacral spine and pelvis. SUMMARY OF BACKGROUND DATA: Low back pain is a common and costly problem that is evaluated and treated primarily by medical physicians, orthopedists, and chiropractors. Although radiology is used extensively in patients with low back pain, the radiographic interpretations of students, clinicians, radiology residents, and radiologists have never been compared. METHODS: Four hundred ninety-six eligible volunteers from nine target groups completed a test of radiographic interpretation consisting of nineteen cases with clinically important radiographic findings. The nine groups included 22 medical students, 183 chiropractic students, 27 medical radiology residents, 13 chiropractic radiology residents, 66 medical clinicians (including 12 general practice physicians, 25 orthopedic surgeons, 21 orthopedic residents, and 8 rheumatologists), 46 chiropractic clinicians, 48 general medical radiologists, 55 chiropractic radiologists, and 36 skeletal radiologists and fellows. RESULTS: The test established a high level of internal consistency reliability (0.880) and revealed that, in the interpretation of abnormal plain film radiographs of the lumbosacral spine and pelvis, significant differences were found among professional groups (P < 0.0001). Post hoc tests (P < 0.05) revealed that skeletal radiologists achieved significantly higher test results than did all other medical groups; that the test results of general medical radiologists and medical radiology residents was significantly higher than those of medical clinicians; that test results of medical students was significantly poorer than that of all other medical groups; that the performance of chiropractic radiologists and chiropractic radiology residents was significantly higher than that of chiropractic clinicians and chiropractic students; that no significant differences was revealed in the mean values of performance of chiropractic clinicians and chiropractic students; that the test results of chiropractic radiologists, chiropractic radiology residents, and chiropractic students was significantly higher than that of the corresponding medical categories (general medical radiologists, medical radiology residents, and medical students, respectively); that no significant difference in test results was identified between chiropractic radiologists and skeletal radiologists or between chiropractic and medical clinicians; and that the length of time in practice for clinicians and radiologists was not a significant factor in the test results. CONCLUSIONS: These data demonstrate a substantial increase in test results of all radiologists and radiology residents when compared to students and clinicians in both medicine and chiropractic related to the interpretation of abnormal radiographs of the lumbosacral spine and pelvis. Furthermore, the study reinforces the need for radiologic specialists to reduce missed diagnoses, misdiagnoses, and medicolegal complications.

Chiropractic↗

PubMed1995

Glenoid labrum: MR imaging with histologic correlation.

PURPOSE: To document the histopathologic basis of altered intralabral and sublabral signal intensity on magnetic resonance (MR) images. MATERIALS AND METHODS: Ten fresh cadaveric shoulder specimens underwent transaxial MR imaging with T1-weighted, proton-density-weighted, and T2-weighted spin-echo; multiplanar gradient-recalled echo (MPGR); three-dimensional Fourier transform gradient-recalled echo (GRE); spoiled gradient-recalled echo (SPGR); and T1-weighted, fat-suppressed sequences before and after intraarticular injection of gadolinium. Shoulders were then frozen and transversely sectioned, and histologic analysis of the labrum was performed. RESULTS: Altered intralabral signal intensity correlated with fibrovascular tissue, mucoid or eosinophilic degeneration, calcification, ossification, synovial tissue, or combinations of these findings. A sublabral transitional band of intermediate signal intensity correlated with a transitional zone of fibrocartilage. CONCLUSION: There are several causes of altered intralabral signal intensity. A transitional fibrocartilaginous zone correlates with sublabral increased signal intensity. Intraarticular administration of gadolinium improves evaluation of the glenoid labrum.

Aged↗

PubMed1995

Distribution of calcification in the triangular fibrocartilage region in 181 patients with calcium pyrophosphate dihydrate crystal deposition disease.

PURPOSE: To investigate the occurrence of calcification around the triangular fibrocartilage complex in calcium pyrophosphate dihydrate (CPPD) crystal deposition disease. MATERIALS AND METHODS: The radiographs of 316 wrists in 181 patients with a definite or probable diagnosis of CPPD disease were reviewed to determine the occurrence of calcification in the inferior radioulnar joint cartilage, triangular fibrocartilage, lunotriquetral ligament, lunotriquetral cartilage, and triquetral cartilage. RESULTS: The distribution of calcification in the 316 wrists was as follows: inferior radioulnar joint cartilage, 87 wrists (28%), triangular fibrocartilage, 233 (74%); lunotriquetral ligament, 244 (77%); lunotriquetral cartilage, 167 (53%); and triquetral cartilage, 66 (21%). Forty-nine wrists had calcification in the lunotriquetral ligament or cartilage but not in the triangular fibrocartilage; 30 wrists had calcification in the triangular fibrocartilage but not in the lunotriquetral ligament or cartilage. This difference in prevalence was statistically significant (P = .0429). CONCLUSION: Radiologic diagnosis of CPPD crystal deposition disease in the wrist necessitates careful evaluation of the lunotriquetral ligament as well as the triangular fibrocartilage.

Aged↗

PubMed1993

Evidence for accelerated skin wrinkling among developmentally delayed individuals with Down's syndrome.

Down's Syndrome (DS) is a genetic disorder involving mental retardation which is reported to be a condition of accelerated aging. However, few studies exist which examine age-dependent changes in DS and these studies fail to include a control group. In the present study a non-invasive, painless, and easily obtainable measure reflecting age-dependent topographical changes of the skin (skin wrinkling) was obtained in 15 DS subjects, 14 developmentally disabled (DD) (mentally retarded) controls (DD controls) and 16 healthy controls of similar ages ranging from 22 to 51 years. The healthy control group failed to show correlations of skin measures with age, as predicted for the age-range of these subjects, based on results of previous studies. However, the DS group showed significant correlations of all skin measures from relatively non-sun-exposed and sun-exposed skin sites, with age. The DD control also showed significant correlations with age of several but not all skin sites and the correlation coefficients tended to be less than that of the DS; at least, when contrasted with the healthy controls the DS showed greater values of several skin measures suggestive of accelerated skin wrinkling. These results provide evidence for accelerated aging of the skin, and possibly greater effects of sun-exposure on skin wrinkling, in DS and possibly (DD) individuals in contrast to healthy individuals without a genetic disorder and without mental retardation.

Adult↗

PubMed1993

Patterns of vertebral ossification and pelvic abnormalities in paralysis: a study of 200 patients.

To clarify the characteristics, extent, and frequency of spinal ossification and abnormalities of the sacroiliac joint, symphysis pubis, and hip in paralysis, routine radiographs of the lumbar spine, pelvis, and abdomen were retrospectively evaluated in 95 quadriplegic, 105 paraplegic, and 100 age-matched control patients, with attention to age and race and to spinal level and duration of paralysis. The spinal radiographs were evaluated for presence of osteophytes, syndesmophytes, paravertebral ossification, and flowing hyperostosis characteristic of diffuse idiopathic skeletal hyperostosis (DISH); the pelvic radiographs were used to measure the widths of the sacroiliac joint, hip, and symphysis pubis articulations and evaluate for presence of enthesopathy. Bone formation around vertebral bodies was often seen in quadriplegic (n = 41 [43%]) and paraplegic (n = 46 [44%]) patients. In quadriplegic patients, four distinct vertebral ossification patterns were evident: osteophytosis, paraspinal ossification resembling that found in psoriasis, syndesmophytosis, and flowing ossification similar to that in DISH. In paraplegic patients, osteophytosis was most frequent. Vertebral ossification in quadriplegic patients was significantly associated with age (P < .01) and increased in frequency and severity with increasing age.

Adult↗

PubMed1992

Alcoholism-associated spinal and femoral bone loss in abstinent male alcoholics, as measured by dual X-ray absorptiometry.

Although alcoholism is a known risk factor for osteoporosis, there are few published reports on alcoholism-associated bone loss. To study alcoholism-associated bone loss, this study used a dual X-ray absorptiometry (DXA) densitometer to measure lumbar and femoral bone mineral density (BMD) in a previously little-studied population: 32 relatively healthy, nonhospitalized, Caucasian, alcoholic men with a period of abstinence longer than that previously studied (median abstinence 4.0 months, range 3 days-36 months). DXA is a new, highly precise densitometric method with many advantages over the methods used in previous studies. The subjects had statistically significant bone loss at three sites: lumbar spine, femoral neck, and Ward's triangle (multiple correction adjusted two-tailed P < 0.008). Compared to the mean BMD of sex-, age-, and race-matched norms, the subjects' average femoral neck, Ward's triangle, and lumbar BMDs were, respectively, 0.56, 0.69, and 0.57 standard deviations (SDs) below the normative values.

Absorptiometry, Photon↗

PubMed1990

Internal vs. external determinants of coping responses to stressful life-events in the elderly.

Coping appears to function in the relationship between stressful life-events and health. Factors that may influence an individual's use of a particular coping strategy, however, are not well understood. Coping consistency within individuals and across situations was examined in a longitudinal study of 74 independently living elderly persons, as were the effects of the type of event experienced, appraisal of its degree of threat, and demographic variables on coping behaviour. Correlational analyses indicated that coping responses were more a function of event type than of an individual's consistent style. A number of distinct life-events were associated with particular types of coping responses. The degree of threat, one's expectation of the changeability of an event, and one's appraisal of possible courses of action were also correlated with specific coping behaviours. Age was negatively correlated with problem-focused coping and total number of coping responses. This study suggests that the type of stressful event an individual experiences may be a more important general determinant of one's coping response than is one's overriding propensity to cope in a particular way.

Adaptation, Psychological↗

PubMed1989

A shortened MMPI useful for psychiatric screening of the non-institutionalized elderly.

We compared the reliability of the Faschingbauer Abbreviated MMPI (the FAM) to the standard MMPI with a sample of non-institutionalized, independently living elderly individuals. FAM items were extracted from the standard MMPIs of 83 middle-class men and women with a mean age of 74 years. Results indicate that the FAM is correlated highly with the MMPI. Although statistically significant differences were found between the FAM and MMPI forms on some scales, 77% of the profile pairs were judged to satisfy interpretive reliability criteria, and for the profiles that were rejected the FAM was not found to overestimate or underestimate any MMPI scale systematically. The potential value of the FAM as a screening device for elderly individuals who are living in the community is addressed.

Adaptation, Psychological↗

PubMed1989

Gender differences in the circadian temperature rhythms of healthy elderly subjects: relationships to sleep quality.

Body core temperature and subjective sleep quality were measured in 22 healthy elderly men and women while they lived at home and continued their normal daily activities. The acrophase of body temperature was phase-advanced by an average of 1.25 h in the older women compared to the age-matched men. Habitual bedtimes did not differ between men and women, but usual wakeup time and average sleep duration did: women awakened earlier and slept for shorter durations. Women were also less satisfied with their sleep than were the men. For the group, the acrophase of body temperature was significantly positively correlated with habitual bedtime and wakeup time. These data support the notion that age-related changes in the circadian timing system are, in large part, gender-dependent. The findings are also consistent with the hypothesis that alterations in sleep timing and quality that typically accompany aging are closely tied to age-related changes in circadian physiology.

Aged↗

PubMed1987

Periostitis in hypertrophic osteoarthropathy: relationship to disease duration.

The relationship of periostitis to disease duration in primary hypertrophic osteoarthropathy and the association of periostitis with cardiopulmonary disorders (secondary type) were studied in order to define distinguishing features between the two. Radiographic skeletal surveys were performed in 24 patients with hypertrophic osteoarthropathy to analyze pattern (single layer, multilayered, irregular) and site of involvement (diaphysis, metaphysis, epiphysis). The six patients with primary hypertrophic osteoarthropathy and the 11 patients with cyanotic congenital heart disease had thicker, more widespread periostitis involving the diaphysis, metaphysis, and epiphysis, in contrast to abnormalities in the seven patients with hypertrophic osteoarthropathy secondary to carcinoma of the lung. Average cortical bone widths as determined by radiogrammetric measurement of the second metacarpals were significantly greater for the patients with primary hypertrophic osteoarthropathy (8.9 +/- 6.0 mm) and cyanotic congenital heart disease (8.5 +/- 6.4 mm) as compared with the patients with bronchogenic carcinoma (6.0 +/- 3.9 mm). Correlation of radiographic patterns with duration of disease confirms that thicker, more extensive alterations are indicative of long-standing disease. The periostitis of hypertrophic osteoarthropathy is therefore not dependent on the primary or secondary nature of the disease but principally on its duration.

Adolescent↗

PubMed1986

Vertebral-body collapse in focal and diffuse disease: patterns of pathologic processes.

The radiographic patterns of vertebral-body collapse and/or endplate deformity were examined in 99 autopsy specimens of the thoracolumbar spine with benign and malignant disease. Angling of endplates was found to be highly predictive of underlying malignancy, whereas concavity was more suggestive of benign disease, for both individual vertebral bodies and intact spines (P less than .001). Diffuse-concave, diffuse-angled, and focal-angled patterns were more useful (P less than .001) than the focal-concave pattern (P = .07) in distinguishing between benign and malignant disease for superior endplates, whereas all were equally useful (P less than .025) in inferior endplates. Condition of the adjacent disks, location within the spine, and position of the apex of collapse were not predictive. Although these results and subsequent blinded testing suggest that reliable distinction between benign and malignant vertebral collapse is possible, extrapolation to clinical practice may be inappropriate because of population bias in the study and differences in radiographic quality between autopsy specimens and live subjects.

Adult↗

PubMed1981

Effects of lithium carbonate on methylphenidate-induced mood, behavior, and cognitive processes.

Evidence is presented which suggests that lithium modifies the mood and behavioral alterations resulting from IV methylphenidate. Specifically, lithium significantly reduces the level of arousal-activation, euphoria-grandiosity, and the total score of manic-state ratings following a methylphenidate challenge. In addition, lithium appears to be capable of modifying the growth hormone response to methylphenidate.

Adult↗

PubMed1978

Comparison of oral and intravenous methylphenidate.

Oral methylphenidate (1.0 mg/kg) and intravenous methylphenidate (0.5 mg/kg) were compared as to their ability to increase behavioral activation, pulse, blood pressure, and serum growth hormone. Intravenous methylphenidate was considerably more effective than oral methylphenidate in activating behavior and in increasing pulse and blood pressure. Although oral methylphenidate appeared to increase behavioral activation, this effect was not statistically significant.

Administration, Oral↗

PubMed1978

Methylphenidate and serum prolactin in man.

Methylphenidate induces psychostimulation and increases cardiovascular parameters, and its psychostimulant effects have been proposed to occur via a dopaminergic mechanism. The effect of methylphenidate on serum prolactin was utilized as a method of evaluating methylphenidate's central dopamimergic effects. Methylphenidate was not found to exhibit a consistent effect on serum prolactin. Thus, its effect on serum prolactin does not parallel its behavioral activating properties, suggesting that such activation may not involve dopamine. Possibly, norepinephrine or other noncatecholaminergic neurotransmitters are involved in methylphenidate-induced behavioral activation.

Adult↗

PubMed1978

The effect of methylphenidate on serum growth hormone: influence of antipsychotic drugs and diagnosis.

Intravenously administered methylphenidate, 0.5 mg/kg, causes a consistent rise in human serum growth hormone level, with peak values usually occurring 30 minutes after infusion. This rise is attenuated in patients receiving various antipsychotic medications administered on a long-term basis and is decreased in schizophrenic and drug-dependent patients. Methylphenidate causes increases in talkativeness, blood pressure, and pulse that generally parallel increases in serum growth hormone level. However, in contrast to the methylphenidate-induced rise in serum growth hormone level, methylphenidate-induced changes in cardiovascular variables and talkativeness are not altered by antipsychotic medications or diagnostic classification.

Adjustment Disorders↗