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T C Patel

Publications and source records attributed to T C Patel.

15 recordsLinked to original sources
PubMed2004

Evaluation of the future supply and demand for blood products in the United Kingdom National Health Service.

In addition to the clinical management of blood supplies, the UK National Blood Service (NBS) examines short-term supply and demand to predict any potential shortages in blood supplies. However, very little data are available on the medium- and long-term trends. This paper describes blood product use in a United Kingdom Hospital Trust in 1999 and combines it with donor information to project the effect of demographic changes on demand and supply over the next 25 years. Overall, 2801 (4%) inpatients received transfusions of blood products. The proportion of inpatients receiving blood products increased with age. Patients aged >70 years used 46% of the total blood product supply, whereas patients aged <30 years used 10%. The estimated total cost associated with blood product use was pound 2 million during 1999 (2001-2002 prices). The results show that within 20 years, demand for blood products is expected to increase by 20% relative to the supply. The estimates in this study are a valuable aid to better long-term planning of supplies. As there is a paucity of data concerning blood product use in UK hospitals and blood use varies greatly between hospitals, further studies are required to guide blood product use policy.

Adult↗
PubMed2001

Osteogenic protein-1 overcomes the inhibitory effect of nicotine on posterolateral lumbar fusion.

STUDY DESIGN: An established rabbit posterolateral lumbar fusion model was used to evaluate the ability of osteogenic protein-1 to overcome the inhibitory effect of nicotine. OBJECTIVE: To determine whether osteogenic protein-1 should be considered as a bone graft alternative for the patient who smokes. SUMMARY OF BACKGROUND DATA: Smoking interferes with the success of posterolateral lumbar fusion. This inhibitory effect has been attributed to nicotine and confirmed in a New Zealand white rabbit model. Osteoinductive protein-1 has been shown to induce posterolateral spine fusion reliably in the rabbit model. The effectiveness with which osteogenic protein-1 induces fusion in the presence of nicotine has not been studied previously. METHODS: Single-level posterolateral intertransverse process fusions were performed at L5-L6 in 18 New Zealand white rabbits. Either autograft or osteogenic protein-1 was used as grafting material. Nicotine was administered via subcutaneous mini-osmotic pumps. The animals were killed 5 weeks after surgery, and the resulting fusion masses were studied. RESULTS: Three rabbits (17%) were excluded because of complications. By manual palpation, two of the eight nicotine-exposed autograft rabbits (25%) and all of the nicotine-exposed osteogenic protein-1 rabbits (100%) were found to be fused. These results correlated well with those obtained from biomechanical testing. Histologically, the fusion zones of the nicotine-exposed autograft rabbits were distinctly less mature than the fusion masses of the nicotine-exposed osteogenic protein-1 rabbits. CONCLUSION: Osteoinductive protein-1 was able to overcome the inhibitory effects of nicotine in a rabbit posterolateral spine fusion model, and to induce bony fusion reliably at 5 weeks.

Animals↗
PubMed2001

Flexibility analysis of posterolateral fusions in a New Zealand white rabbit model.

STUDY DESIGN: Biomechanics of posterolateral spinal fusion were studied in an in vivo rabbit model. OBJECTIVES: To determine the extent of stabilization produced by posterolateral lumbar fusion and to test the hypothesis that motions are not completely eliminated after successful fusion. SUMMARY OF BACKGROUND DATA: Previous human cadaveric studies, clinical studies, and animal studies have attempted to characterize the biomechanics of posterolateral fusion. Such studies have been limited by either methods of fusion modeling or methods of stability testing. No previous study has examined biologic fusion with a physiologic biomechanical testing technique. METHODS: Ten adult New Zealand white rabbits underwent L5-L6 intertransverse process fusion using autogenous iliac crest bone graft. Rabbits were killed 5 weeks after surgery. Only one time point was studied. This time point was chosen because previous pull-apart studies have shown plateauing of rabbit fusion mass strength and stiffness around this time. Spines were then harvested and evaluated with manual palpation and an established flexibility testing protocol. Resulting data were compared with previously acquired, nonoperative spine flexibility data. RESULTS: Two animals were excluded because of complications. Of those that were fused (n = 5), biomechanical testing revealed significant decreases in flexion (81%), extension (61%), and right and left lateral bending (67% and 83%, respectively) (P < 0.01). CONCLUSIONS: These findings define the amount of motion reduction that can be expected with posterolateral fusions in the rabbit model at 5 weeks. These results suggest that motion was significantly decreased but was not eliminated.

Animals↗
PubMed2001

2000 Young Investigator Research Award winner. Evaluation of OP-1 as a graft substitute for intertransverse process lumbar fusion.

STUDY DESIGN: An established rabbit intertransverse process lumbar fusion model was used to evaluate osteogenic protein (OP)-1 as a potential graft substitute. OBJECTIVES: To determine whether OP-1 is effective in producing intertransverse process lumbar fusion in a rabbit model. SUMMARY OF BACKGROUND DATA: Autogenous iliac crest bone is the gold standard in grafting material for inducing intertransverse process fusion. However, bone graft substitutes are being considered as supplementary or alternative means to achieve such fusion with less morbidity. Relatively little research has been undertaken to investigate the efficacy of OP-1 in this role. METHODS: Single-level intertransverse process lumbar fusions were performed at L5-L6 of 31 New Zealand White rabbits. These were divided into three study groups: autograft, carrier alone, and carrier with OP-1. The animals were killed 5 weeks after surgery. Resultant fusion masses were evaluated by manual palpation, radiography, biomechanical multidirectional flexibility testing, and histology. RESULTS: Seven rabbits (23%) were excluded because of complications. Of the remaining 24 rabbits, 5 (63%) of the 8 in the autograft group had fusion detected by manual palpation, none (0%) of the 8 in the carrier-alone group had fusion, and all 8 (100%) in the OP-1 group had fusion. Radiographs were 55% sensitive and 92% specific for determining fusion. Biomechanical testing results correlated well with those of manual palpation. Histologically, autograft specimens were predominantly fibrocartilage, OP-1 specimens were predominantly maturing bone, and carrier-alone specimens did not show significant bone formation. CONCLUSIONS: OP-1 was found to reliably induce solid intertransverse process fusion in a rabbit model at 5 weeks.

Animals↗
PubMed2000

Disc degeneration: a human cadaveric study correlating magnetic resonance imaging and quantitative discomanometry.

STUDY DESIGN: This human cadaveric study evaluated disc degeneration of the lumbar spine using magnetic resonance imaging and quantitative discomanometry. OBJECTIVE: To determine if a correlation exists between magnetic resonance imaging and quantitative discomanometry in determining disc degeneration of the lumbar spine. SUMMARY OF BACKGROUND DATA: Several studies analyzing disc degeneration of the lumbar spine have compared magnetic resonance imaging with discography and discomanometry. The reported results are conflicting. No studies exist that compare magnetic resonance imaging and quantitative discomanometry in assessing the disc degeneration of the lumbar spine. METHODS: Three fresh human cadaveric thoracolumbar spine specimens (two T11-S1 and one L1-S1) that included a total of 19 discs were used. Spines were scanned with magnetic resonance imaging, and the scans were read by a neuroradiologist. Using the quantitative discomanometry technique, discs were injected with normal saline, and pressure-volume curves were collected and quantified with six parameters: intrinsic pressure, leakage pressure, initial slope, slope from 0.0 to 0.1 mL, maximum pressure, and volume at maximum pressure. Data analysis was performed using Spearman's Rank Correlation (Rho) statistic. RESULTS: Based on the results from 19 discs, an overall good correlation between magnetic resonance imaging scores and the six quantitative discomanometry parameters was demonstrated. With exception of the volume at maximum pressure, correlation coefficients ranged between 0.61 to 0.78 with a P < 0.05. CONCLUSIONS: Magnetic resonance imaging scores and quantitative discomanometry parameters correlated well in the assessment of disc degeneration of the lumbar spine. Quantitative discomanometry may be an important technique for evaluating early disc degeneration, especially tears of the anular fibers, which may be missed on magnetic resonance imaging.

Aged↗
PubMed2000

Muscle response pattern to sudden trunk loading in healthy individuals and in patients with chronic low back pain.

STUDY DESIGN: A quick-release method in four directions of isometric trunk exertions was used to study the muscle response patterns in 17 patients with chronic low back pain and 17 matched control subjects. OBJECTIVES: It was hypothesized that patients with low back pain would react to sudden load release with a delayed muscle response and would exhibit altered muscle recruitment patterns. SUMMARY OF BACKGROUND DATA: A delay in erector spinae reaction time after sudden loading has been observed in patients with low back pain. Muscle recruitment and timing pattern play an important role in maintaining lumbar spine stability. METHODS: Subjects were placed in a semiseated position in an apparatus that provided stable fixation of the pelvis. They exerted isometric contractions in trunk flexion, extension, and lateral bending. Each subject performed three trials at two constant force levels. The resisted force was suddenly released with an electromagnet and electromyogram signals from 12 trunk muscles were recorded. The time delay between the magnet release and the shut-off or switch-on of muscle activity (reaction time) was compared between two groups of subjects using two-factor analysis of variance. RESULTS: The number of reacting muscles and reaction times averaged over all trials and directions showed the following results: For healthy control subjects a shut-off of agonistic muscles (with a reaction time of 53 msec) occurred before the switch-on of antagonistic muscles (with a reaction time of 70 msec). Patients exhibited a pattern of co-contraction, with agonists remaining active (3.4 out of 6 muscles switched off) while antagonists switched on (5.3 out of 6 muscles). Patients also had longer muscle reaction times for muscles shutting off (70 msec) and switching on (83 msec) and furthermore, their individual muscle reaction times showed greater variability. CONCLUSIONS: Patients with low back pain, in contrast to healthy control subjects, demonstrated a significantly different muscle response pattern in response to sudden load release. These differences may either constitute a predisposing factor to low back injuries or a compensation mechanism to stabilize the lumbar spine.

Adult↗
PubMed2000

Biomechanical evaluation of the New Zealand white rabbit lumbar spine: a physiologic characterization.

Physiologic motions of the human, sheep, and calf lumbar spines have been well characterized. The size, cost, and ease of care all make the rabbit an attractive alternative choice for an animal lumbar spine model. However, comparisons of normal biomechanical characteristics of the rabbit lumbar spine have not been made to the spines of larger species. The purpose of this study was to establish baseline physiologic kinematic data for the rabbit lumbar spine. Ten skeletally mature New Zealand white rabbit osteoligamentous spines were obtained. L4-L7 spine segments were harvested and mounted. Multi-directional flexibility testing was performed by applying pure moments up to 0.27 Nm. Resulting rotations were measured using an Optotrak system. Data were analyzed for each intervertebral level in the three planes of rotation. The three levels tested had roughly similar range of motion (ROM). The mean (SD) angular ROMs in flexion for L4-L5, L5-L6, L6-L7 were 12.10 degrees (2.59 degrees), 12.38 degrees (2.70 degrees), and 15.17 degrees (3.22 degrees), respectively. The ROMs in extension were 5.86 degrees (1.21 degrees), 5.58 degrees (1.48 degrees), and 6.13 degrees (2.03 degrees). Lateral bending and axial rotation were roughly symmetric due to the symmetric nature of the spine. For right lateral bending, the ROMs were 8.25 degrees (2.44 degrees), 4.96 degrees (1.70 degrees ), and 4.25 degrees (1.20 degrees). For left axial rotation, the ROMs were 1.23 degrees (1.16 degrees), 0.35 degrees (0.61 degrees), 0.87 degrees (0.64 degrees ). Neutral zone (NZ) was on average 60% (29%) of ROM for the motions studied. The physiologic ROM of the New Zealand white rabbit lumbar spine was found to be similar between the rabbit and human. This relatively conserved physiologic flexibility supports the use of the rabbit as a model of the lumbar spine for kinematic studies. However, the overall NZ was found to be a greater percentage of ROM in the rabbit than the corresponding percentage in the human (60% as compared to 25%). This suggested that the rabbit lumbar spine has a greater laxity than that of the human.

Animals↗
PubMed2000

Congenital scoliosis.

Congenital scoliosis is a deformity of the developing spine that results from defects in vertebral development. The developmental etiologies may be classified as either a failure of formation, a failure of segmentation, or a mixture of these two modes of maldevelopment. Early detection and close surveillance of congenital scoliosis is critical, as a rapidly progressive curve may lead to significant deformity, pulmonary restriction, and neurologic problems if not treated. Early surgical treatment is often necessary for rapidly progressive curves.

Cervical Vertebrae↗
PubMed1999

Scheuermann's kyphosis.

Scheuermann's disease is a kyphotic deformity of the spine that develops in early adolescence. This condition has been reported to occur in 0.4% to 8% of the general population, with an equal distribution between sexes. Diagnosis of Scheuermann's disease is suggested on clinical examination; however, parents of children affected often confuse it with poor posture. Radiographs are the standard imaging modality used to confirm the diagnosis of Scheuermann's disease. Classic signs include vertebral end plate irregularity, disk space narrowing, and anterior wedging of involved vertebral bodies. Other diagnostic tools such as CT scans or magnetic resonance imaging may also be of value in the evaluation of Scheuermann's disease. The mode of treatment for this condition depends upon the severity of the deformity, remaining growth, and presence or absence of symptoms. Early treatment may be limited to observation and exercises, whereas patients who have kyphosis of up to 75 degrees and how have growth remaining may benefit from bracing. Surgical correction is reserved for severe cases that are symptomatic and refractory to conservative management.

Adolescent↗
PubMed1997

Ceramide induces hepatocyte cell death through disruption of mitochondrial function in the rat.

Although ceramide signaling pathways have been implicated in cell death, neither their role in hepatocellular death nor the cellular mechanisms mediating ceramide-induced cell death are known. The mitochondrial membrane permeability transition (MMPT) has been proposed as a common final pathway in cell death. Thus the aims of our study were to determine if ceramides cause hepatocellular death by necrosis and not apoptosis as confirmed by morphology and the absence of internucleosomal DNA cleavage. Ceramide-mediated hepatocyte necrosis was acyl chain-length, concentration, and time-dependent. Ceramides induced cell necrosis was associated with adenosine triphosphate (ATP) depletion and mitochondrial depolarization suggesting that ceramides caused mitochondrial dysfunction. In isolated mitochondria, ceramides induced the cyclosporine A-sensitive MMPT in an acyl chain-length and concentration dependent manner. Ceramide toxicity was specific as the less potent dihydro form did not induce cell necrosis, significant ATP depletion, mitochondrial depolarization nor the MMPT. In conclusion, ceramide induced cell death is acyl-chain length dependent and mediated by the MMPT. These data show for the first time that ceramide acts as a mediator of hepatocyte necrosis by causing mitochondrial failure.

Adenosine Triphosphate↗
PubMed1996

Role of plasmapheresis in thrombocytopenic purpura associated with Waldenström's macroglobulinemia.

A 67-year-old man with Waldenström's macroglobulinemia had a relapse of chronic idiopathic thrombocytopenic purpura (ITP), which had been refractory to corticosteroids, splenectomy, vinca alkaloids, and high-dose intravenous gamma-globulin therapy. A biclonal gammopathy (IgM kappa and IgG lambda) was detected in his serum and was likely responsible for his refractory thrombocytopenia. He was treated with chlorambucil and prednisone. Plasmapheresis was effective in temporarily maintaining platelet counts and in decreasing morbidity until immunosuppression was completely effective against the production of the monoclonal protein. The previously reported experiences with use of plasmapheresis in patients with chronic ITP are discussed. Plasmapheresis may be of value in the treatment of selected patients with severe ITP and monoclonal gammopathy.

Aged↗
PubMed1993

Resting thallium-201 scintigraphy for identifying viable myocardium in a patient with severe left ventricular dysfunction.

Recognizing patients with coronary artery disease in whom severe left ventricular dysfunction is attributed to a chronic decrease in myocardial blood flow without infarction is often difficult but important because such patients may benefit from surgical revascularization. Herein we describe a patient with severe left ventricular dysfunction who had appreciable resting wall motion abnormalities; tomographic thallium-201 myocardial scintigraphy performed while the patient was resting identified viable myocardium. Subsequent revascularization improved regional and global left ventricular function considerably.

Aged↗
PubMedDate not supplied

Inspired air temperature with immersion heater humidifiers.

The temperature of aerosol mixture delivered from 2 types of immersion heater humidifiers was monitored at various sites along the delivery tube. As anticipated, the temperature of the humidified gas decreased as it moved distally from the aerosol generator to the T-adaptor in contact with patient's airway. The immersion heaters with fixed-temperature thermostatic control performed consistently, though most produced inhaled air temperatures higher than desired (greater than 37 degrees C). Immersion heaters with temperature reset features were in general unreliable and invariably gave higher inspired air temperatures with higher settings of the thermostat.

Aerosols↗