Search PubMed⌕ Search

Biomedical subjects

R C Smith

Publications and source records attributed to R C Smith.

At least 73 records · Page 4Linked to original sources
PubMed1999

Determination of skeletal muscle and fat-free mass by nuclear and dual-energy x-ray absorptiometry methods in men and women aged 51-84 y (1-3).

BACKGROUND: Skeletal muscle mass (SMM) and fat-free mass (FFM) are important variables in nutritional studies. Accurate techniques for measuring these variables have not been thoroughly validated in elderly subjects. OBJECTIVES: The objectives of this study were to 1) compare SMM values derived from dual-energy X-ray absorptiometry (DXA) with those calculated by a nuclear method from total body potassium (TBK) and total body nitrogen (TBN) measurement (both: KN) in older subjects, and 2) assess the accuracy of FFM measurement by DXA in these subjects. DESIGN: TBK, TBN, DXA (model XR36; Norland, Fort Atkinson, WI), bioimpedance, and anthropometric measurements were performed on healthy women (n = 50) and men (n = 25) aged 51-84 y. RESULTS: Mean SMM by KN was not significantly different from SMM by DXA in either sex. SMM by KN predicted SMM by DXA with an SEE of 2.1 kg (r = 0.95, P < 0.0001 for women and men together). In the men, FFM by DXA agreed well with FFM estimated by TBK, skinfold thicknesses, bioimpedance analysis, and a multicompartment model. In women, FFM by DXA was 4-5 kg less than that by the other methods (P < 0.01). Truncal fat was related to intermethod FFM differences (r = 0.58, P < 0.0001). CONCLUSIONS: These data indicate that 1) either the nuclear or the DXA method can be applied to estimate SMM in healthy older subjects, and 2) the Norland DXA instrument significantly underestimates FFM in older women, in part, because of the influence of truncal adiposity.

Absorptiometry, Photon↗
PubMed1999

Nonresponding schizophrenia: differentiation by neurological soft signs and neuropsychological tests.

Schizophrenia patients have higher scores on neurological soft-signs (NSS) and show greater deficits on a variety of neuropsychological tests than normal control subjects and mixed groups of psychiatric patients. Among chronic schizophrenia patients it is unclear which of these types of deficits most strongly differentiates patients who remain consistently symptomatic in spite of treatment with several conventional neuroleptics (nonresponders) as compared with relapsing chronic schizophrenia patients who improve substantially with treatment (relative responders). In this study, 25 nonresponders and 20 relative responders to conventional neuroleptics were compared on an NSS battery and a limited number of neuropsychological tests, which evaluated deficits influenced by functioning of frontal and nonfrontal brain areas. NSS scores showed the largest difference between relative responders and nonresponders, and statistical analyses suggested that NSS scores were the strongest differentiator between the two groups of chronic schizophrenia patients. Scores differentiating the two groups involved deficits influenced by both frontal and nonfrontal functioning. A predominance of negative symptoms in the current clinical picture was highly correlated with high NSS scores.

Adult↗
PubMed1999

Teaching self-awareness enhances learning about patient-centered interviewing.

PURPOSE: To evaluate the effect of intensive attitudinal training on residents' learning the patient-centered interviewing skills required to establish a healthy provider-patient relationship and to communicate effectively. METHOD: While teaching 53 residents patient-centered interviewing skills, the authors also trained them to recognize previously unrecognized, negative attitudes that interfered with learning the skills. The authors, using an iterative, consensus-building process based on the residents' performances and personality data, identified a spectrum of responses to the educational intervention. Barriers to and facilitators of mastery of skills were analyzed and this information was used to help residents overcome skill deficits. RESULTS: To varying degrees, 44 residents became aware of previously unrecognized attitudes to the extent that they improved their patient-centered interviewing skills. Six residents failed to develop awareness of negative attitudes and showed little learning and clinical use of the interviewing skills being taught. Three residents who rapidly developed superb interviewing skills showed no negative attitude towards using them. CONCLUSIONS: Pending a confirmatory hypothesis-testing study, the authors believe that, as residents learn how to conduct patient-centered interviews, training in awareness of interfering attitudes should accompany training in skills.

Attitude of Health Personnel↗
PubMed1999

Reexamining the value of hematuria testing in patients with acute flank pain.

PURPOSE: Hematuria testing is routinely performed in patients with acute flank pain to screen for ureterolithiasis and to help determine the need for excretory urography. Unenhanced helical computerized tomography (CT) has recently been shown to be superior to excretory urography in diagnosing ureteral obstruction and can evaluate many other causes of flank pain. Given the speed, accuracy and safety of CT the value of hematuria testing for acute flank pain should be reexamined. MATERIALS AND METHODS: We reviewed the medical records of 267 consecutive patients with acute flank pain referred for unenhanced helical CT. Microscopic and dipstick urinalysis data were obtained in 195 patients. Using helical CT as the gold standard, we calculated the sensitivity, specificity, predictive value and accuracy of hematuria for diagnosing ureterolithiasis. RESULTS: Of the patients with ureterolithiasis 33% had 5 or less, 19% had 1 or less and 11% had no red blood cells (RBCs) per high power field. Of the patients without ureterolithiasis 24% had greater than 5 and 51% had greater than 1 RBC per high power field. Of the patients with ureterolithiasis 14% had a negative dipstick test and 1 RBC or less per high power field. There were 25 patients without ureterolithiasis who had CT abnormalities unrelated to the urinary tract, of whom 8 had greater than 1 RBC per high power field. CONCLUSIONS: Absence of hematuria in the setting of acute flank pain cannot exclude a diagnosis of ureterolithiasis and should not obviate other diagnostic testing. Even when strongly positive on microscopy, hematuria has insufficient positive predictive value for diagnosing ureterolithiasis and may be misleading as other serious conditions resulting in acute flank pain may yield a positive test.

Acute Disease↗
PubMed1999

Parenteral amino acid intake alters the anabolic actions of insulin-like growth factor I in rats.

The anabolic properties of insulin-like growth factor (IGF) I are attenuated by oral diets that are low in protein. However, it is not known whether parenteral nutrition (PN) providing a low amino acid (AA) input will influence IGF-I action. With the use of a rat model, this study examined the interaction between AA input (1.27 and 0.62 g N. kg body wt(-1). 24 h(-1), AA and 1/2AA groups, respectively) and recombinant human IGF-I (rhIGF-I, 2.5 mg. kg body wt(-1). 24 h(-1)) infusion on the composition of the carcass and organs and on plasma insulin, IGF-I, IGF-binding protein 1 (IGFBP-1), and acid-labile subunit (ALS) concentrations. Carcass protein deposition only occurred in the AA groups (P < 0.003) and was not influenced by administration of rhIGF-I. However, visceral protein loss persisted in the AA group but was prevented by rhIGF-I infusion. The changes in water content of the carcass and the organs were generally in the expected proportion of normal lean tissue. The accumulation of lipid that follows the infusion of the AA-deficient PN was prevented by rhIGF-I infusion, which may indicate an improved energy utilization. Neither serum insulin nor ALS concentrations were influenced by the level of AA infusion but were reduced by rhIGF-I administration. However, plasma IGF-I levels were elevated by higher AA infusion and by IGF-I administration. Also, IGFBP-1 concentrations were reduced by the higher AA infusion and increased with rhIGF-I administration. Interestingly, there was a significant interaction effect between both of these influences. It is concluded that free IGF-I concentration, which may be regulated by IGFBP-1 through a direct effect of AAs on the liver, may have an important role in regulating anabolism in visceral and possibly skeletal tissue during PN.

Amino Acids↗
PubMed1999

Stability of neurological soft signs in chronically hospitalized schizophrenic patients.

Neurological soft signs (NSS) have been shown to be more prevalent in chronically ill and in acute or never-mediated patients with schizophrenia. If neurological soft signs are trait-like, then NSS scores should be relatively stable over time and should not be related to changes in patients' psychopathology or medication. Chronically hospitalized patients with schizophrenia were rated two or more times over a 5-year period with standard NSS and psychopathology scales. Total NSS scores were highly correlated over time, and changes in NSS scores at two time points were not significantly related to changes in psychopathology scores. Total NSS scores did not change significantly in a subsample rated when they were first treated with a traditional neuroleptic and later with an atypical neuroleptic. The findings suggest total NSS scores may have some characteristics of a trait-like feature in chronically hospitalized patients with schizophrenia.

Adult↗
PubMed1999

Epidural analgesia reduces the release of amino acids from peripheral tissues in the ebb phase of the metabolic response to major upper abdominal surgery.

The purpose of this prospective cohort study was to compare metabolic effects of epidural or patient controlled analgesia (PCA) in patients undergoing major upper abdominal surgery. Seventeen patients undergoing major upper abdominal surgery were included: 10 received perioperative epidural analgesia (Group I) and the remainder received morphine via a PCA device for postoperative analgesia (Group II). A number of measures compared between one day preoperatively (day 1) and day 2 postoperatively included femoral arterial and venous blood concentrations of glucose, lactate, pyruvate and amino acids. In addition, the relevant flux values were measured from the products of the respective arteriovenous substrate concentration differences and calf blood flow. The efflux of lactate from peripheral tissues was greater in Group II than in Group I (P < 0.01): glucose and pyruvate efflux did not differ between groups. There was no difference between groups in mean individual and total flux of amino acids on day-1. However increased efflux between day-1 and day 2 was found for alanine, valine, isoleucine, leucine, phenylalanine, lysine, arginine in both groups, and for serine, glycine, tyrosine and histidine in Group II (P < 0.05). The efflux of glycine, methionine, amino benzoic acid, alanine, and lysine was less in Group I than Group II on day 2 (P < 0.05). There was a significant difference in the total amino acid flux on day 2 (Group I = -1.2 mumol. (100 ml tissue)-1.min-1 cf Group II = -2.5 mumol. (100 ml tissue)-1.min-1; P = 0.04). In conclusion, perioperative epidural analgesia was associated with a reduced postoperative amino acid efflux two days following major upper abdominal surgery.

Amino Acids↗
PubMed1999

Imaging appearances of Sister Mary Joseph nodule.

Sister Mary Joseph nodules are metastatic deposits in the periumbilical area. The purpose of this review is to demonstrate umbilical anatomy, discuss modes of metastatic spread, the various imaging appearances and their relevance to the radiologist.

Adult↗
PubMed1999

Distinguishing pelvic phleboliths from distal ureteral stones on routine unenhanced helical CT: is there a radiolucent center?

OBJECTIVE: On radiographs of the abdomen and pelvis, phleboliths often have a characteristic radiolucent center that helps to distinguish them from ureteral stones. On unenhanced CT, the distinction between pelvic phleboliths and distal ureteral stones can be problematic. The objective of this study was to compare the appearance of phleboliths on routine clinical CT studies with their appearance on radiography and to determine if the radiolucent center seen on radiographs is revealed on CT. SUBJECTS AND METHODS: During a 3-month interval, we identified 50 patients with acute flank pain who underwent both unenhanced CT and abdominal radiography. Patients with a radiograph of the pelvis and an unenhanced CT scan obtained within 1 month of each other were included. CT was performed with a collimation of 5 mm and a pitch of 1. Each phlebolith was examined using soft-tissue and bone settings and was also retrospectively pixel mapped. RESULTS: Seventy-nine (66%) of 120 phleboliths revealed radiolucent centers on abdominal radiography. On CT, 119 (99%) of 120 phleboliths failed to reveal a low-attenuation center on both visual inspection and pixel mapping. CONCLUSION: Pelvic phleboliths were shown to lack a radiolucent center on routine clinical CT examinations despite their appearance on radiography. A radiolucent center therefore cannot be used to differentiate phleboliths from distal ureteral stones on unenhanced CT in patients with acute flank pain and suspected ureteral obstruction.

Adult↗
PubMed1999

The value of prone scanning to distinguish ureterovesical junction stones from ureteral stones that have passed into the bladder: leave no stone unturned.

OBJECTIVE: When a stone is located in the region of the ureterovesical junction on CT studies, it is important to determine if the stone is impacted at the ureterovesical junction or has already passed into the bladder. The purpose of this study was to determine if CT findings can be used to distinguish stones impacted at the ureterovesical junction from stones that have already passed into the bladder. SUBJECTS AND METHODS: From February 1, 1997, to January 31, 1998, 37 patients with acute flank pain underwent unenhanced CT studies in the supine position that showed stones in the region of the ureterovesical junction. To determine stone location, limited rescans were obtained with the patients in the prone position. The supine images were reviewed retrospectively by one of the authors, who was unaware of the findings of the prone scans. Forty-one stones were classified as being impacted at the ureterovesical junction or as having passed into the bladder. RESULTS: On CT, 23 stones were correctly classified as being impacted at the ureterovesical junction; nine stones were correctly classified as having passed into the bladder; and nine stones were incorrectly classified as being within the bladder. We calculated a sensitivity of 72%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 50%, and an accuracy of 78% for CT in revealing stones impacted at the ureterovesical junction. CONCLUSION: If patients are imaged in the supine position only, unenhanced helical CT cannot reliably distinguish stones impacted at the ureterovesical junction from stones that have already passed into the bladder. A prone scan can be used to make this distinction.

Adolescent↗
PubMed1999

Sensitivity and value of digital CT scout radiography for detecting ureteral stones in patients with ureterolithiasis diagnosed on unenhanced CT.

OBJECTIVE: When unenhanced CT reveals ureterolithiasis, some patients will require baseline or follow-up conventional radiography to help guide clinical management. We sought to determine the sensitivity of routinely obtained scout radiographs for revealing stones to determine if the scout view can be used in place of baseline conventional radiography. MATERIALS AND METHODS: We retrospectively reviewed the CT scout radiographs in conjunction with axial CT images in a series of 215 consecutive patients in whom CT revealed a single ureteral stone. On the scout radiographs, stones were classified as definitely visible, definitely not visible, or indeterminate. In addition, a phantom was constructed using fragments of kidney stones to evaluate the effect of the digital scout kilovoltage settings on stone visualization. RESULTS: Forty-nine percent of stones were definitely visible on scout radiography, 47% were definitely not visible, and 4% were indeterminate. Four stones larger than 10 mm that were not visible on scout radiography were composed of uric acid (n = 2) or xanthine (n = 2). Scout radiographs of the phantom determined an optimal kilovoltage setting of 80-100 kVp to visualize stones less than 3 mm, whereas stones greater than or equal to 3 mm were visible at all kilovoltage settings. CONCLUSION: In our series, 49% of ureteral stones were visible on the often-overlooked routine CT scout radiograph. Imaging of phantoms showed that stone visualization can be optimized by using the lowest kilovoltage settings. Therefore, the CT scout view can be used as a baseline study in patients requiring follow-up radiography and for planning treatment of patients requiring lithotripsy or other intervention. Finally, large stones not visible on scout radiographs are likely composed of uric acid or xanthine.

Abdominal Pain↗
PubMed1999

Clinical usefulness of MR imaging of the breast in the evaluation of the problematic mammogram.

OBJECTIVE: This study was undertaken to determine the usefulness of MR imaging of the breast as an adjunct to mammography in problematic cases in which the significance, presence, or location of an abnormality could not be determined. MATERIALS AND METHODS: From January 1993 through February 1998, 86 lesions for which histologic or mammographic follow-up was available were evaluated by breast MR imaging because of equivocal findings on mammography. MR studies were performed with a dedicated breast multicoil on a 1.5-T scanner. Early studies were done using a T1-weighted two-dimensional spin-echo sequence before and after the administration of contrast material. Later studies were performed using a three-dimensional fast spoiled gradient sequence with fat suppression. Studies were considered to be positive for an abnormality if a focal area of enhancement was seen after contrast administration. RESULTS: MR imaging had positive findings in 38 sites. Twenty-six of these sites corresponded in location to the mammographic abnormality that had prompted the recommendation for MR imaging. The remaining 12 sites occurred in areas not suspected mammographically. At biopsy, 10 (26%) of the 38 positive sites were malignant. MR imaging had negative findings at 60 other sites that had been suspected mammographically. Of these 60 sites, six were treated with excision, all with benign results; the remaining 54 sites showed mammographic stability on follow-up that ranged from 5 to 66 months (mean, 19 months). CONCLUSION: MR imaging of the breast can be a valuable adjunct to mammography for selected problematic cases.

Adult↗
PubMed1998

Identification of a novel metastasis-suppressor region on human chromosome 12.

There is a critical need for markers that can be used to predict accurately the malignant potential of histological prostate cancers (J. T. Isaacs. Am. J. Pathol., 150: 1511-1521, 1997). Metastasis-suppressor genes are attractive candidates for marker development because, by definition, their loss should be associated with the acquisition of metastatic ability. In an effort to identify such genes, a single copy of human chromosome 12, tagged with the neomycin resistance gene, was introduced into highly metastatic Dunning AT6.1 prostate cancer cells by microcell-mediated chromosomal transfer. Thirty-two AT6.1-12 clonal cell lines were established and the region(s) of chromosome 12 retained was determined by sequence tagged site-based PCR analysis. Representative AT6.1-12 clones containing overlapping regions of chromosome 12 were characterized cytogenetically and were shown to have a normal complement of parental AT6.1 rat chromosomes. Fluorescence in situ hybridization, performed on representative AT6.1-12 hybrids, demonstrated a single human chromosome 12-specific signal. The metastatic ability of six representative clones was tested in immunodeficient mice. All of the AT6.1-12 clones showed the same in vivo growth rates as the control AT6.1-neo cells. Clonal cell lines that contained a conserved approximately 70-cM portion of chromosome 12 (e.g., AT6.1-12-8, -8-1, and -8-3), showed a >30-fold suppression in the number of macroscopic surface lung metastases. Mice that received injections of these cells developed a mean number 4 lung metastases whereas mice that received injections of other AT6.1-12 hybrids (lacking the approximately 70-cM region) or AT6.1-neo control cells, developed a mean number of 140 metastases. Interestingly, histological examination of the lungs of the mice that received injections of AT6.1-12-8 cells showed essentially no microscopic metastases. These findings suggest that a gene(s) encoded by the approximately 70-cM portion of human chromosome 12 suppresses an early step in the metastatic cascade.

Animals↗
PubMed1998

GATA-6 induces p21(Cip1) expression and G1 cell cycle arrest.

GATA transcription factors represent a family of highly conserved zinc finger proteins with tissue-specific expression patterns. Previous studies have shown that GATA-6 is expressed in vascular smooth muscle cells (VSMCs) and rapidly down-regulated when VSMCs are induced to proliferate. Here we investigated whether the GATA-6 transcription factor can modulate cellular proliferation. Transient transfection with a GATA-6 expression vector inhibited S-phase entry in VSMCs and in mouse embryonic fibroblasts (MEFs) lacking both p53 alleles. The GATA-6-induced growth arrest correlated with a marked increase in the expression of the general cyclin-dependent kinase (Cdk) inhibitor p21. In contrast to p53-deficient MEFs and VSMCs, MEFs null for both p21 alleles were refractory to the GATA-6-induced growth inhibition. These data demonstrate that elevated GATA-6 expression can promote the quiescent phenotype in VSMCs.

Animals↗
PubMed1998

The effectiveness of intensive training for residents in interviewing. A randomized, controlled study.

BACKGROUND: Interviewing and the physician-patient relationship are crucial elements of medical care, but residencies provide little formal instruction in these areas. OBJECTIVE: To determine the effects of a training program in interviewing on 1) residents' attitudes toward and skills in interviewing and 2) patients' physical and psychosocial well-being and satisfaction with care. DESIGN: Randomized, controlled study. SETTING: Two university-based primary care residencies. PARTICIPANTS: 63 primary care residents in postgraduate year 1. INTERVENTION: A 1-month, full-time rotation in interviewing and related psychosocial topics. MEASUREMENTS: Residents and their patients were assessed before and after the 1-month rotation. Questionnaires were used to assess residents' commitment to interviewing and psychosocial medicine, estimate of the importance of such care, and confidence in their ability to provide such care. Knowledge of interviewing and psychosocial medicine was assessed with a multiple-choice test. Audiotaped interviews with real patients and videotaped interviews with simulated patients were rated for specific interviewing behaviors. Patients' anxiety, depression, and social dysfunction; role limitations; somatic symptom status; and levels of satisfaction with medical visits were assessed by questionnaires and telephone interviews. RESULTS: Trained residents were superior to untrained residents in knowledge (difference in adjusted post-test mean scores, 15.7% [95% CI, 11% to 20%]); attitudes, such as confidence in psychological sensitivity (difference, 0.61 points on a 7-point scale [CI, 0.32 to 0.91 points]); somatization management (difference, 0.99 points [CI, 0.64 to 1.35 points]); interviewing of real patients (difference, 1.39 points on an 11-point scale [CI, 0.32 to 2.45 points]); and interviewing (data gathering) of simulated patients (difference, 2.67 points [CI, 1.77 to 3.56 points]). Mean differences between the study groups were consistently in the appropriate direction for patient satisfaction and patient well-being, but effect sizes were too small to be considered meaningful. CONCLUSION: An intensive 1-month training rotation in interviewing improved residents' knowledge about, attitudes toward, and skills in interviewing.

Attitude of Health Personnel↗
PubMed1998

Detection of urethral diverticula in women: comparison of a high resolution fast spin echo technique with double balloon urethrography.

PURPOSE: We compared a rapid high resolution magnetic resonance imaging (MRI) technique to contrast urethrography for the detection of urethral diverticula in women. MATERIALS AND METHODS: During a 19-month interval 13 patients with clinically suspected urethral diverticula were evaluated with MRI and contrast urethrography. All patients were referred by a urologist, and had clinical signs and symptoms suggesting the presence of a urethral diverticulum. Double balloon urethrography was performed in 12 patients and voiding cystourethrography was done in 1. MRI was performed using a fast spin echo T2-weighted pulse sequence and a dedicated pelvic multicoil. Following a sagittal localizer sequence 3 mm. thick axial sections were obtained from the bladder base through the entire urethra. Total imaging time was 15 minutes. RESULTS: In 7 patients MRI and urethrography were negative for urethral diverticula, and in 3 cystourethroscopy was negative. In 1 patient MRI revealed a vaginal inclusion cyst confirmed by surgery. Three patients had no other studies or procedures performed. In 6 patients MRI was positive for urethral diverticula, including 4 in whom the diverticulum was confirmed at surgery, 1 who declined surgery and 1 who was lost to followup. Of the 4 patients (75%) with a surgically confirmed diverticulum double balloon urethrogram was negative in 3. CONCLUSIONS: MRI is a valuable noninvasive technique for determining the presence of urethral diverticula as well as detecting other abnormalities. In our study MRI had a higher sensitivity for detecting diverticula and a much higher negative predictive rate.

Diverticulum↗