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Biomedical subjects

D Rama

Publications and source records attributed to D Rama.

11 recordsLinked to original sources
PubMed2001

Skeletal troponin-I release in orthopedic and soft tissue injuries.

The skeletal isoform of troponin-I (sTnI) is a myofibrillar protein highly specific for myoskeletal injury. We used an indirect immunoenzymometric assay method with high analytical sensitivity to measure sTnI in patients with soft-tissue injury and in orthopedic patients. We assessed 20 soft-tissue injury patients and 16 orthopedic patients for sTnI, cardiac troponin-I (cTnI), creatine kinase (CK), myoglobin, and elastase within 24h of injury, in comparison with 17 control subjects. The mean (SD) ng/ml value for sTnI was higher in orthopedic patients (15.25 +/- 2.4) and in soft-tissue injury patients (10.41 +/- 1.8) than that in controls (2.5 +/- 0.9) P < 0.001, P < 0.05 respectively. Cardiac TnI was not detectable in any subjects (below the assay detectable limit of 0.3ng/ml). CK was significantly higher in orthopedic patients than in controls (P < 0.005) and myoglobin and elastase were not significantly changed in patients samples. The assay appeared to be suitable as a supplementary tool of reliability and relevance, for the study, identification, and diagnosis of skeletal muscle specific injuries in humans.

Adult↗
PubMed2000

Specialized intestinal metaplasia in patients with gastro-oesophageal reflux disease.

BACKGROUND: There is an increasing awareness that short (less than 3 cm) segments of Barrett's epithelium and macroscopically normal cardia epithelium may harbour specialized intestinal metaplasia (SIM), a premalignant phenotype. The prevalence of SIM was studied prospectively in an unselected population of patients attending for endoscopy, and the association of SIM with symptoms, lifestyle, medication, endoscopic oesophagitis and carditis was investigated. METHODS: Two hundred consecutive patients underwent endoscopy. Biopsies taken from just below the squamocolumnar junction were stained for SIM, and were analysed for carditis and Helicobacter pylori infection. A detailed questionnaire of symptoms, tobacco consumption and the use of proton pump inhibitors was completed. RESULTS: Forty-two patients (21 per cent) had SIM: 19 (15 per cent) of 126 in an endoscopically normal oesophagus, 15 (24 per cent) of 63 in a short segment of Barrett's epithelium and eight of 11 in classical Barrett's oesophagus. There was a significant association between SIM and carditis (P < 0.0001) and endoscopic oesophagitis (P = 0.03). CONCLUSION: SIM is prevalent in patients undergoing endoscopy, does not correlate with symptoms or H. pylori infection, but is significantly associated with endoscopic and pathological markers of gastro-oesophageal reflux.

Adolescent↗
PubMed2000

Cardiovascular tolerance of healthy elderly subjects to weight-lifting exercises.

OBJECTIVE: To evaluate the hemodynamic strain and the myocardial tolerance of weight-lifting exercises in healthy elderly subjects. METHODS: Sixty-five healthy elderly subjects (32 men/33 women) aged 65-80, were studied. Weight-lifting exercises consisted of two sets of 12 repetitions at 12-repetition maximum (RM) and four sets of five repetitions at 5-RM for, horizontal leg press, seated chest press, and bilateral leg extension movements. Cardiovascular tolerance to weight-lifting exercises was evaluated both physiologically and biologically by measuring heart rate (HR) and blood pressures continuously during exercise, and cardiac troponin I (cTnI) blood concentration before and 6 h postexercise. Comparisons between resting and exercise or postexercise values were performed by a bilateral-paired t-test. A value of P < 0.05 was considered statistically significant. RESULTS: No significant increase in cTnI circulating concentration was observed secondary to exercise (16.56+/-2.23 vs 14.40+/-1.96 ng x L(-1); mean +/- SEM). This was observed despite a significant (P < 0.001) exercise-induced increase in systolic (SAP) and diastolic arterial pressures (DAP) and HR. Highest values of SAP, DAP, and HR (223.6+/-3.1 mm Hg, 139.6+/-1.9 mm Hg, and 108+/-2 min(-1), respectively) were measured during the horizontal leg press exercise. CONCLUSION: These data suggest that weight-lifting exercises can be conducted in healthy elderly subjects without clinical, electrical, and biological sign of myocardial ischemia, if appropriate selection criteria, and proper respiratory techniques during exercise are applied.

Aged↗
PubMed1999

Reduced reflex sensitivity persists several days after long-lasting stretch-shortening cycle exercise.

The mechanisms related to the acute and delayed secondary impairment of the stretch reflex function were investigated after long-lasting stretch-shortening cycle exercise. The results demonstrated a clear deterioration in muscle function immediately after fatigue, which was accompanied by a clear reduction in active and passive reflex sensitivity. For active and passive stretch reflexes, this reduction was biphasic (P < 0.05 to P < 0.001). However, for the ratio of the electrically induced maximal Hoffmann reflex to the maximal mass compound action potential, only one significant reduction was seen immediately after fatigue (71.2%, P < 0.01). A similar significant (P < 0.01) decrease in the stretch-resisting force of the muscle was also detected. Clear increases were found in the indirect markers of muscle damage (serum creatine kinese activity and skeletal troponin I), which could imply the occurrence of ultrastructural muscle damage. It is suggested that the acute reduction in reflex sensitivity is of reflex origin and due to two active mechanisms, disfacilitation and presynaptic inhibition. However, the delayed second decline in the sensitivity of some reflex parameters may be attributable to the secondary injury, because of some inflammatory response to the muscle damage. This might emphasize the role of presynaptic inhibition via group III and IV muscle afferents.

Adult↗
PubMed1999

Effects of bone fracture and surgery on plasma myosin heavy chain fragments of skeletal muscle.

OBJECTIVE: Myosin heavy chain (MHC) fragment is part of a structural or force-bearing protein expressed in the thick filament of muscle fibres. Since MHC fragment is a contractile protein, an increase in plasma MHC concentrations after muscle injury indicates degradation of the contractile apparatus. This study was conducted to determine whether MHC concentrations could be a tool in the assessment of tissue damage in patients with myoskeletal injuries. DESIGN: Prospective, controlled study. SETTING: A UK University National Health Service Centre. PATIENTS: Thirty-eight orthopedic patients, of whom 14 received surgical treatments within the 2-day study period. Patients were compared with 16 nonorthopedic control subjects. OUTCOME MEASURES: Serum levels of MHC, creatine kinase, cardiac troponin I (cTnI), and myoglobin were measured at the time of admission and 24 hours later. Data from patients undergoing surgical repairs were obtained 24 hours after surgery. A competitive radio-immunoassay for beta-type MHC was used. RESULTS: Plasma MHC concentration was higher in the patients than in the controls. The peak levels were observed 24 hours after injury or surgery (p < 0.05). cTnI concentrations were consistently below the assay detection limit of 0.3 microgram/L, thus excluding protein release from the heart muscle (cardiac beta-type MHC). Creatine kinase and myoglobin concentrations were significantly higher on admission in the non-surgical patients than in the surgically treated cases. CONCLUSIONS: Serum MHC levels could be a useful supplementary retrospective, prognostic or diagnostic tool in the study of myoskeletal disturbances involving muscle injury or bone fractures that result in membrane leakage of myoskeletal cells.

Adult↗
PubMed1997

Epitope localization of monoclonal antibodies used in human troponin I immunoenzymometric assay.

Serum troponin I isoforms have proven to be potent markers of striated muscle injury. They reach the blood-stream soon after their liberation from the damaged muscular cell and can be detected by the use of selected antibodies. Among monoclonal antibodies (MAbs) originally produced against cardiac troponin I (cTnI), two MAbs able to cross react with the skeletal isoform of troponin I (sTnI) were selected and used to develop a one-step immunoenzymometric assay which allows the quantification of both cardiac and skeletal isoforms (scTnI IEMA). The present report describes the main characteristics of this assay. By using multiple peptide synthesis methods, the localization of the epitopes recognized by the two MAbs on sTnI were determined. The capture and tracer MAbs of the scTnI IEMA were shown to recognize epitopes located within positions 121-127 and 160-167 in the sTnI sequence, respectively. The results of this epitopic analysis are discussed in light of the cross reaction of these two MAbs with cTnI.

Antibodies, Monoclonal↗
PubMed1997

Skeletal troponin I as a marker of exercise-induced muscle damage.

The utility of skeletal troponin I (sTnI) as a plasma marker of skeletal muscle damage after exercise was compared against creatine kinase (CK), myoglobin (Mb), and myosin heavy chain (MHC) fragments. These markers were serially measured in normal physical education teacher trainees after four different exercise regimens: 20 min of level or downhill (16% decline) running (intensity: 70% maximal O2 uptake), high-force eccentric contractions (70 repetitions), or high-force isokinetic concentric contractions of the quadriceps group (40 repetitions). Eccentrically biased exercise (downhill running and eccentric contractions) promoted greater increases in all parameters. The highest plasma concentration were found after downhill running (median peaks: 309 U/l CK concentration (-CK-)), 466 microgram/l Mb concentration (-Mb-), 1,021 microU/l MHC concentration (-MHC-), and 27.3 microgram/l sTnI concentration ([sTnI]). Level running produced a moderate response (median peaks: 178 U/l -CK-, 98 microgram/l -Mb-, 501 microU/l -MHC-, and 6.6 microgram/l [sTnI]), whereas the concentric contraction protocol did not elicit significant changes in any of the markers assayed. sTnI increased and peaked in parallel to CK and stayed elevated (>2.2 microgram/l) for at least 1-2 days after exercise. In contrast to MHC, sTnI is an initial, specific marker of exercise-induced muscle injury, which may be partly explained by their different intracellular compartmentation with essentially no (MHC <0.1%) or a small soluble pool (sTnI: median 3.4%).

Adult↗
PubMedDate not supplied

Levels of myosin heavy chain fragment in patients with tissue damage.

BACKGROUND: Myosin heavy chain fragments (MHC) levels are observed to be higher in myoskeletal injuries after surgery. MHC could be a helpful supplementary tool in the study of myoskeletal injuries. METHODS: Serum levels of myosin heavy chain fragments (MHC) were assessed in orthopedic patients before operation (OBO) and after operative (OAO) repairs and in the early phase of soft tissue injury (STI) using a radioimmunoassay involving monoclonal antibodies to the human beta-type MHC. RESULTS: Mean (SD) microU/L of MHC in comparison with the control subjects (75.3 +/- 47.1) was higher in OAO (305.8 +/- 38.1) p <0.0001, and no significant changes in MHC were found in STI (67 +/- 77.5). Myoglobin was notably higher in OBO (81.9 +/- 95.0) compared to STI (43.9 +/- 55.9) or controls p <0.05, but there was no further change in the protein after surgery. The mean proportional raised level of myoglobin in OBO was >twofold, and MHC increased by 27%. Neither myoglobin nor MHC increased in the plasma of the STI within 24 h of injury. CONCLUSIONS: These data suggest that the release of MHC could be a helpful supplementary tool in the study of tissue damage in humans.

Antibodies, Monoclonal↗