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Biomedical subjects

S Rajasekaran

Publications and source records attributed to S Rajasekaran.

At least 37 records · Page 2Linked to original sources
PubMed2004

Decreased bioavailability of rifampin and other antituberculosis drugs in patients with advanced human immunodeficiency virus disease.

We evaluated the effects of human immunodeficiency virus (HIV) disease on pharmacokinetics of antituberculosis medications by measuring concentrations of isoniazid and rifampin in blood and of pyrazinamide and ethambutol in urine. Peak concentration and exposure were reduced for rifampin, and rapid acetylators of isoniazid had lower drug levels. HIV and HIV-tuberculosis patients who have diarrhea and cryptosporidial infection exhibit decreased bioavailability of antituberculosis drugs.

Acetylation↗
PubMed2003

Malabsorption of rifampin and isoniazid in HIV-infected patients with and without tuberculosis.

The absorption of rifampin, isoniazid, and D-xylose in patients with human immunodeficiency virus (HIV) infection and diarrhea, in patients with HIV infection and tuberculosis (TB), in patients with pulmonary TB alone, and in healthy subjects was studied. Percentage of dose of the drugs, their metabolites, and D-xylose excreted in urine were calculated. A significant reduction in the absorption of drugs and D-xylose in both the HIV infection/diarrhea and HIV infection/TB groups was observed (P<.05), and the correlation between them was significant. Our results indicate that patients with HIV infection and diarrhea and those with HIV infection and TB have malabsorption of rifampin and isoniazid.

Adolescent↗
PubMed2003

Baastrup's disease as a cause of neurogenic claudication: a case report.

STUDY DESIGN: A rare case of Baastrup's disease as a cause of spinal canal stenosis in a patient with double-level spondylolisthesis is reported. OBJECTIVES: To report an intraspinal synovial cyst as an extension of neoarthrosis of Baastrup's disease causing spinal canal stenosis, and to review the relevant literature. SUMMARY OF BACKGROUND DATA: Baastrup's disease, more commonly known as kissing spines, has been implicated as a cause for low back pain. Neoarthrosis between the spinous processes has been described, but this is the first report in the literature of an extension of the synovial cavity to the intraspinal space resulting in extradural compression. METHODS: A 50-year-old woman with double-level spondylolisthesis and symptoms of instability and neurogenic claudication was evaluated and treated using spinal decompression and fusion. RESULTS: Radiographs showed a double-level spondylolisthesis at L3-L4 and L4-L5 levels, and magnetic resonance imaging showed the presence of a neocyst formation in the interspinous region and another cyst in the posterior epidural space at the same level causing dural compression. There was a suggestion of continuity between the two cysts that was confirmed at surgery. The neoarthrosis and the cyst were excised, and spinal decompression and fusion were performed. The patient had good relief of symptoms. CONCLUSIONS: Baastrup's disease leading to neoarthrosis formation with synovial cavity and causing low back pain has been reported previously. The cyst can enter into the epidural space through the midline cleft of the ligamentum flavum to result in extradural compression.

Female↗
PubMed2003

Spontaneous tendon ruptures in alkaptonuria.

Ochronosis, the musculoskeletal manifestation of alkaptonuria, is known to lead to degenerative changes of the spine and weight-bearing joints. Symptoms related to degeneration of tendons or ligaments with spontaneous ruptures have not previously been reported. Three patients are described with four spontaneous ruptures of either the patellar tendon or tendo Achillis as the first symptom of alkaptonuria.

Achilles Tendon↗
PubMed2002

The efficient computation of position-specific match scores with the fast fourier transform.

Historically, in computational biology the fast Fourier transform (FFT) has been used almost exclusively to count the number of exact letter matches between two biosequences. This paper presents an FFT algorithm that can compute the match score of a sequence against a position-specific scoring matrix (PSSM). Our algorithm finds the PSSM score simultaneously over all offsets of the PSSM with the sequence, although like all previous FFT algorithms, it still disallows gaps. Although our algorithm is presented in the context of global matching, it can be adapted to local matching without gaps. As a benchmark, our PSSM-modified FFT algorithm computed pairwise match scores. In timing experiments, our most efficient FFT implementation for pairwise scoring appeared to be 10 to 26 times faster than a traditional FFT implementation, with only a factor of 2 in the acceleration attributable to a previously known compression scheme. Many important algorithms for detecting biosequence similarities, e.g., gapped BLAST or PSIBLAST, have a heuristic screening phase that disallows gaps. This paper demonstrates that FFT algorithms merit reconsideration in these screening applications.

Algorithms↗
PubMed2002

The problem of deformity in spinal tuberculosis.

Spinal tuberculosis is the most common cause for a kyphotic deformity in patients in many parts of the world. There is an average increase of 15 degrees deformity in all patients who are treated conservatively and 3% to 5% of patients may end up with a deformity that is greater than 60 degrees. The progress of deformity occurs in two distinct phases: Phase I, which includes the changes in the active phase, and Phase II, which includes changes after the disease is cured. The progress of deformity is influenced by the severity of the angle before treatment, the level of the lesion, and age of the patient. Adults have an increase less than 30 degrees during the active phase with no additional change. Children, in contrast, have significant changes even in the healed phase of the disease. During the growth spurt, there is worsening of the deformity in 39% (Type I progression), an improvement in 44% (Type II), and no change in 17% (Type III). Children at risk of late progressive deformity can be identified early by the presence of spine-at-risk radiologic signs. Surgery for preventing deformity must be done earlier rather than later and in patients with severe disease, stabilization by the use of posterior and anterior instrumentation is necessary to obtain a good outcome.

Adult↗
PubMed2002

Evaluation of the phenol ammonium sulfate sedimentation smear microscopy method for diagnosis of pulmonary tuberculosis.

We compared the sensitivity and specificity of the phenol ammonium sulfate (PhAS) sediment smear microscopy method for detection of acid-fast bacilli with those of direct smear microscopy, using culture results for Mycobacterium tuberculosis as the "gold standard." The sensitivities of the PhAS and direct smear methods were 85% (465 of 547) and 83% (454 of 547), respectively, and the specificity of each method was 97%. The PhAS method was better accepted by the laboratory technicians and safer but necessitates an overnight sedimentation, which delays reporting of results until 1 day after sputum collection.

Ammonium Sulfate↗
PubMed2002

Inefficiency of 0.3% carbol fuchsin in ziehl-neelsen staining for detecting acid-fast bacilli.

We compared the sensitivity and specificity of a modified Ziehl-Neelsen (modified-ZN) staining method for acid-fast bacilli (AFB) with that of the standard Ziehl-Neelsen (standard-ZN) staining method, using culture results with Mycobacterium tuberculosis as the "gold standard." The sensitivity (72%; 101 of 140) of the modified-ZN staining method, which uses 0.3% carbol fuchsin, was significantly lower than that of the standard-ZN staining method (84%; 117 of 140); the modified-ZN method missed 21% of cases detected by the standard-ZN method and 11% more of culture-positive samples than the standard-ZN method. The World Health Organization recommendation of 0.3% carbol fuchsin in the ZN method for staining AFB needs to be reconsidered.

Coloring Agents↗
PubMed2001

The natural history of post-tubercular kyphosis in children. Radiological signs which predict late increase in deformity.

The progression of post-tubercular kyphosis in 61 children who received ambulatory chemotherapy was studied prospectively. The angles of deformity and kyphosis were measured for each patient at diagnosis, 3, 6, 9, 12 and 18 months later and every year thereafter for 15 years. During the course of the disease signs of instability appeared on the radiographs of some of the children. These were dislocation of the facets, posterior retropulsion of the diseased fragments, lateral translation of the vertebrae in the anteroposterior view and toppling of the superior vertebra. Each sign was allocated one point to create a spinal instability score. The influence on the progression of the deformity of the level of the lesion, the vertebral body loss, the number of segments involved, the angle of deformity before treatment and the spinal instability score was analysed. The mean angle of deformity at the start of treatment was 35 degrees. This increased to 41 degrees at 15 years. Progression occurred during the active phase of the disease and again after cure when variations in progression were observed. Type-I progression showed an increase in deformity until growth had ceased. This could occur either continuously (type Ia) or after a lag period of three to five years (type Ib). Type-II progression showed decrease in deformity with growth. This could occur immediately after the active phase (type IIa) or after a lag period of three to five years (type IIb). Type-III progression showed minimal change during either the active or healed phases and was seen only in those with limited disease. Multiple regression analysis showed that a spinal instability score of more than 2 was a reliable predictor of patients with an increase of more than 30 degrees in deformity and a final deformity of over 60 degrees. Since signs of radiological instability appear early in the disease, they can be reliably used to identify children whose spine is at risk for late progressive collapse. Surgery is advised in these cases.

Adolescent↗
PubMed2000

Clinical correlates of 6-hydroxydopamine injections into A11 dopaminergic neurons in rats: a possible model for restless legs syndrome.

Pursuant to the clinical suspicion that restless legs syndrome (RLS) may involve dopaminergic diencephalic spinal neurons (A11), we performed stereotaxic bilateral 6-hydroxydopamine (6-OHDA) lesions into the A11 nucleus to observe for any behavioral correlates similar to this clinical condition. Pathologic examination demonstrated a 54% reduction in A11 tyrosine hydroxylase staining cells in rats injected with 6-OHDA versus sham treatment. Multiple blindly rated 90-120-minute video epochs demonstrated an increased average number of standing episodes (14.4+/-11.7 versus 7.3+/-5.5 episodes/epoch) and increased total standing time (38.9+/-20.5 versus 25.3+/-12.2 minutes/epoch) but similar total sleep time in four lesioned rats when compared with two sham rats. Treatment of the lesioned rats with intramuscular pramipexole subsequently resulted in fewer standing episodes (4.4+/-3.3 versus 14.4+/-11.7 episodes/epoch) and less total standing time (20.9+/-12.3 versus 38.9+/-20.5 minutes/epoch) when compared with untreated lesioned rats. Despite a large number of observations, the small number of lesioned animals precluded formal statistical analysis. These behaviors are consistent, although not specific, with what would be expected in an animal model of RLS.

Adrenergic Agents↗
PubMed1998

Tuberculous lesions of the lumbosacral region. A 15-year follow-up of patients treated by ambulant chemotherapy.

STUDY DESIGN: A 15-year clinical follow-up of tuberculous lesions of the lumbosacral region. OBJECTIVES: To verify the hypothesis that the lumbar lordosis and the specific biomechanics of the lumbosacral region influence and alter the healing pattern and progress of the disease when compared with their effects in other regions of the spine. SUMMARY OF BACKGROUND DATA: An estimated 2 million or more patients have active spinal tuberculosis, and the global incidence of the disease is increasing. The involvement of the lower lumbar region and the lumbosacral junction is relatively rare, with few reports in English literature. METHODS: Of a total of 304 patients forming a part of a controlled clinical trial comparing two forms of therapy in spinal tuberculosis, 53 patients had involvement of L3 and below. The following data were studied in these patients: age at start of treatment, number of vertebra involved, vertebral body loss, progress of the angle of kyphosis, and anterior and posterior growth of the involved segment during a period of 15 years. Student's t test for independent samples was used for statistical analysis. RESULTS: The fourth lumbar vertebra was the most common vertebral segment involved, and the lumbosacral junction was affected in 12 patients. The average pretreatment kyphosis was 6.4 degrees and increased to 10.2 degrees at the end of 15 years. The average kyphotio angle per vertebral body loss was 4.9 degrees, far less than in the dorsolumbar region in which kyphotic angles of 27-30 degrees have been reported. Children younger than 10 years old differed in clinical appearance and progress compared with those older than 17 years. They not only showed more extensive involvement but also had more deformity with the same vertebral loss. Twelve patients less than 10 years old had an average involvement of 3.1 vertebral bodies and an average vertebral loss of 2.2 bodies. In comparison, the average number of vertebrae involved was 1.9 (P < 0.01) and the vertebral body loss was only 0.87 (P < 0.01) in patients older than 17 years. Also, the average kyphosis was 6.4 degrees compared with only 4.2 degrees (P < 0.01) in adults. In patients older than 17 years, there was no change after 2 years, by which time the collapse was complete. Four of 12 patients less than 10 years old, showed progressive kyphosis caused by continued growth of posterior parts of the body (i.e., sequestrated hemivertebrae). CONCLUSIONS: In tuberculosis of the lumbosacral region, the development of kyphosis is minimal in patients older than 17 years, when growth has already stopped, and deformity is expressed more as foreshortening of the trunk. Children younger than 10 years old have more severe involvement with increased tendency toward greater kyphosis. They are also prone to progressive deformity through the years when the anterior growth plates are destroyed. Surgery is indicated in this group to prevent greater deformity.

Adolescent↗
PubMed1995

Trend of HIV infection in patients with pulmonary tuberculosis in south India.

SETTING: Tuberculosis is life threatening, transmissible and pandemic especially among millions of HIV infected persons. In developing countries like India where HIV infection is becoming prevalent and where tuberculosis infection has long been endemic, its incidence is increasing. OBJECTIVE: The aim of the study was to find out the trend of HIV infection in patients with pulmonary tuberculosis in south India. DESIGN: HIV seropositivity was assessed in 1430 radiologically and/or bacteriologically confirmed pulmonary tuberculosis patients attending major tuberculosis institutions in Madras by the AIDS Cell, Institute of Microbiology, Madras Medical College, Madras from January 1991 to May 1993. RESULTS: HIV seropositivity was found to rise significantly from 0.77% in 1991 to 3.4% in 1993 (P < 0.05). 22 (91.67%) of a total of 24 HIV seropositive pulmonary tuberculosis patients had pulmonary cavities and 21 patients (87.5%) had bacteriological confirmation of tuberculosis. CONCLUSION: The findings of this prospective study suggest that pulmonary tuberculosis patients with HIV infection are an in early phase of immunosuppression. This study reveals the rising trend of HIV infection; all persons with tuberculosis should therefore be questioned about the risk factors for HIV infection and urged to have an HIV test.

Adult↗
PubMed1994

Eighteen-level analysis of vertebral rotation following Harrington-Luque instrumentation in idiopathic scoliosis.

We used the Perdriolle method to measure the rotation of each vertebra from the seventh cervical to the fifth lumbar level, before and after posterior spinal arthrodesis and Harrington-Luque instrumentation in fifteen patients who had idiopathic scoliosis. The primary curve was corrected an average of 50 per cent and the secondary curve, an average of 73 per cent. Following the operation, the average number of vertebrae involved in the primary curve increased from seven (range, five to ten) to nine (range, seven to fifteen). The rotation of the apical vertebra of the primary curve increased 10 degrees in four patients and 5 degrees in two patients and decreased 5 degrees in one patient. The rotation of the apical vertebra of the secondary curve increased 10 degrees in three patients and 5 degrees in one patient and decreased 5 degrees in four patients. In seven patients, correction of the curve was associated with unexpected counter-rotation, beyond the levels of instrumentation, of three or more vertebral segments that had been in neutral position before the operation.

Adolescent↗
PubMed1991

Locked finger due to foreign body in the flexor sheath.

A patient is described in whom a wooden splinter penetrated the finger and impaled the flexor tendons. It was pulled out but part remained inside and the finger could not be moved until an operation was performed and the remaining part of the splinter removed.

Adolescent↗
PubMed1989

Progression of kyphosis in tuberculosis of the spine treated by anterior arthrodesis.

The case of eighty-one patients who had tuberculosis of the spine that was treated by debridement and anterior arthrodesis were reviewed eight years or more postoperatively. We studied the progression of the kyphosis and evaluated the function and fate of the bone grafts that were used. At eight years, the results with respect to the progression of the kyphosis were classified as excellent or good in forty-eight patients (59 per cent), all of whom had had minimum destruction of the vertebral bodies; limited surgical excision of bone, resulting in a small post-debridement defect that needed only a short graft; marked intraoperative correction of the deformity; and involvement of lower lumbar segments. Fifteen patients (19 per cent) had a fair result and eighteen (22 per cent), a poor result. An increase in the deformity was common in patients who had extensive involvement of the vertebral bodies that had resulted in a large post-debridement defect necessitating a graft spanning more than two disc spaces. Lesions of the thoracic vertebrae were associated with many of the poor results, and patients who had a marked kyphosis before treatment also did not do well. A stable graft that provided structural support was observed in only thirty-three patients (41 per cent), and failure of the graft due to slippage, fracture, absorption, or subsidence was seen in forty-eight patients (59 per cent). The length of the graft also played a role: the graft failed most often in patients in whom it spanned more than two disc spaces. We concluded that it is unwise to rely solely on the graft to prevent vertebral collapse in patients in whom the length of the graft exceeds two disc spaces. These patients may benefit from additional measures, such as an extended period of non-weight-bearing, posterior arthrodesis after six to twelve weeks, and prolonged use of a brace until complete consolidation is evident.

Adolescent↗
PubMed1987

Prediction of the angle of gibbus deformity in tuberculosis of the spine.

The cases of ninety patients who had tuberculous lesions in the thoracic and thoracolumbar spine were studied. A comparison of the angles of the gibbus deformity at onset and six years later showed statistically significant differences between the patients who underwent treatment by radical surgery and those who underwent treatment by one of two non-surgical regimens. Analysis of the amount of the initial loss of vertebral body and of the final angle of the gibbus deformity at six years showed a correlation coefficient of 0.83. Using the formula y = a + bx, the final angle of the gibbus deformity was predictable with 90 per cent accuracy in the patients who were not treated surgically. The ability to predict the final angle of the gibbus deformity allows the surgeon to select the patients who will require radical resection and bone-grafting to prevent a severe kyphosis.

Adolescent↗