Biomedical subjects
Publications and source records attributed to S Rajan.
Endometriosis is only rarely the cause of massive bloody ascites. This entity simulates gynecological malignancy and is seldom recognized before surgical exploration of the abdomen. It is more commonly seen in black nulliparous females. Hormonal modulation has obviated the need for surgical resection, in some cases. We report a case of such an entity and review the medical literature.
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OBJECTIVE: To determine the pathogenesis of muscular symptomatology in the eosinophilia-myalgia syndrome (EMS). METHODS: P31-nuclear magnetic resonance spectroscopy (MRS) was performed on 7 patients with EMS and 10 age matched controls to determine the relative concentrations of phosphocreatine (PCr), inorganic phosphate (Pi), and adenosine triphosphate (ATP) in calf muscle. RESULTS: Patients with EMS had statistically lower ATP/PCr ratios and higher Pi/ATP ratios than controls, indicating a preferential and unique decrease in ATP levels at rest in skeletal muscle. CONCLUSION: Skeletal muscle is metabolically abnormal in patients with EMS. This abnormality may contribute to the myalgia, spasm, and weakness seen in this disorder.
Between 1978 and 1993 a total of 25 cases of ruptured aneurysm of the sinus of Valsalva underwent transaortic repair at the Railway Hospital and the Institute of Cardiovascular Diseases at Madras, India. The aneurysms ruptured into the right ventricle in 20 patients, into the right atrium in 2, into the left ventricle in 1, and into the interventricular septum in 2. They originated from the right coronary sinus in 22 patients and from the noncoronary sinus in 3. Associated congenital anomalies included ventricular septal defect in 21, tetralogy of Fallot in 1, and pulmonary stenosis in 1. All 25 patients underwent transaortic repair of the ruptured sinus of Valsalva, and in patients with a ventricular septal defect the defect also was closed via this route. The patient with associated pulmonary stenosis had a pulmonary valvotomy. The patient with tetralogy of Fallot had infundibular resection, ventricular septal defect closure via a transatrial route, and a right ventricular outflow patch. No intraoperative deaths occurred, but one early death resulted from septicemia and multiorgan failure after rupture of the aneurysm into the interventricular septum with consequent development of extensive intramyocardial and epicardial abscesses. One late death occurred as a result of recurrent subacute bacterial endocarditis and septicemia. Transaortic repair of ruptured aneurysm of the sinus of Valsalva can be accomplished with a low risk of mortality and has the advantage that an associated ventricular septal defect, which frequently accompanies this condition, can be conveniently closed via the same route.
It is often difficult for the radiologist to determine if a given sacral meningeal cyst is causing symptoms. Radiographic criteria for identifying cysts likely to be symptomatic are needed. Using conventional magnetic resonance (MR) imaging along with a specifically designed flow-sensitive sequence, the authors characterized 24 cysts (19 patients) with respect to diameter and communication with the subarachnoid space. They found no significant difference in size between symptomatic and asymptomatic cysts (P > .05) but did observe a clear-cut disparity in the context of communication: Five of five asymptomatic cysts were shown to communicate on MR flow studies, while seven of seven symptomatic cysts were not shown to communicate. The authors propose that flow-sensitive MR imaging is useful in differentiating communicating from noncommunicating sacral meningeal cysts and that this information may be of value in classifying these lesions as more or less likely to be symptomatic.
Alcoholic extract of leaf and stem bark of A. excelsa at a dose of 250 mg equivalent of plant material/kg body weight, exhibited remarkably high anti-implantation and early abortifacient activities. The results are in agreement with the traditional use of this plant as a abortifacient by the Irula women of the Nilgiri district.
Tissue inhibitors of metalloproteinases (TIMPs) constitute a family of secreted glycoproteins involved in regulating extracellular matrix degradation in both normal and malignant tissues. We have expressed a cDNA clone of mouse TIMP-1 as a 22-kDa protein with 12 cysteine residues in E. coli and purified protein that shows inhibitory activity against collagenase following renaturation by chemical means. The low specific activity and circular dichroism measurements suggest, however, that the renaturation of the mouse recombinant (non-glycosylated) protein is not efficient under the conditions we have used, indicative of either thermodynamic instability or the transition to kinetic intermediates which have very low in vitro refolding rates.
A case of spontaneous rupture of an adventitial cyst in the popliteal artery is reported. Axial magnetic resonance (MR) images demonstrated the decompressed cyst, and MR angiography was a useful noninvasive technique for confirming vascular patency after cyst rupture.
A Pseudomonas stutzeri isolate rapidly reduced both selenite and selenate ions to elemental selenium at initial concentrations of both anions of up to 48.1 mM. Optimal selenium reduction occurred under aerobic conditions between pH 7.0 and 9.0 and at temperatures of 25 to 35 degrees C. Reduction of both selenite and selenate was unaffected by a number of anions except for sulfite, chromate, and tungstate ions, which inhibited both growth and reduction.
A great deal of interest is being shown in complaint bearing surfaces for artificial joints. These produce very low friction because of the fluid-film lubrication that they exhibit, and therefore should produce lower wear than current prosthetic materials as the two surfaces of the joint are completely separated by a film of synovial fluid. However, one problem with soft elastic materials in vivo is that the elastomers may degrade with time. Specimens of four polyurethanes were kept in Ringer's solution at 37 degrees C for about 4 months to investigate changes in mechanical properties and the mode of lubrication with time of immersion. The materials tested were a polyether-urethane (E57), a polyester-urethane (E58), an aromatic polyether-urethane (P1) and an aliphatic polyether-urethane (A1). Samples of E57 showed a decrease in hardness and elastic modulus of 21% and 28% respectively. This was much better than E58 which showed decreases of 32% and 42% respectively. Better results were achieved with A1 (hardness change 2%) and P1 (decrease in hardness of 14% and modulus 17%). When tested in a hip-function simulator, A1 showed virtually no change in its very low coefficient of friction (0.004), P1 showed an increase of 60%, while E57 and and E58 both showed a doubling in friction over the course of the study. The modes of in vitro degradation were considered and surface effects determined to be most damaging. Currently the best candidate for a compliant material in hip replacement is the aliphatic polyether-urethane which maintains fluid-film lubrication.
The clinical use of cryopreserved allograft valves is rapidly increasing. Viability of valve leaflet fibroblasts has been proposed to be critical to durability. Harvesting of allograft valves involves variable warm ischemia times, defined as the time from cessation of donor heart beat to initial cooling for transport. This ischemic period has been implicated as one of the more critical periods of injury to leaflet cell, even though adequate characterization of this potentially injurious phase has never been accomplished. The present study was undertaken to characterize the metabolic response to warm ischemia in a porcine valve leaflet model. Valve handling was similar to clinical valve harvest and transport protocols. Injury was assessed by protein (1H) and phosphorus (31P) magnetic resonance spectroscopy of 224 porcine semilunar valves. Leaflets were analyzed over time for lactate accumulation and ATP degradation. A radiolabelled incubation assay (48 valves) was used to measure proline accumulation by fibroblasts. Electron microscopy was performed on 36 valves with varying warm ischemia times. ATP stores were entirely depleted after 2 h hypoxia (p less than 0.05). However, lactate continued to accumulate over 24 h. Although aerobic metabolism ceased after 2 h warm ischemia, anaerobic metabolism continued for up to 24 h, which may represent an extended window for harvesting fresh tissue for allograft valve implantation.
It is known that trihalomethanes (THM) are formed during chlorination of drinking water for disinfection. Heightened concern about these substances is due to the fact that THMs are now characterized as potential mutagen, carcinogen and teratogen. Thus, it is a risk factor in human beings. In the present study, a total number of 13 stations located in different drinking water trunk mains of the city of Madras were analysed for THM using the Gas Liquid Chromatographic method. It is reported that THM are formed after treatment of raw water with chlorine at the levels required for disinfection. The THM level in drinking water increased towards the dead-end of the water trunk mains. A relationship between the distance travelled by the potable water and the level of THM was established. At certain stations, the total trihalomethanes level (TTHM) was found to exceed the EPA's maximum contaminant level. Further, an intermittent addition of the precursors for the formation of THM through the seepage of polluted River Cooum water into the pipe lines has been demonstrated. An experiment on the trihalomethane formation potential (THMFP) clearly revealed the occurrence of higher magnitude of humic substances in source water. Therefore, it is suggested that if suitable steps are not taken, various environmental factors may trigger the THM kinetics. Hence, it is obvious that pretreatment regulations proposed by developed countries are essential if safe drinking water is to be supplied to the people of Madras.
The combined loss of the Achilles tendon and the overlying soft tissue in the young ambulant patient with expectations of a normal life is a challenge. These patients need not only skin coverage but also dynamic, functioning repair. Two cases of major defects after tumour resection are presented. In each case the tendon was reconstructed using the remaining gastrocnemius aponeurosis reinforced with fascia lata. This was covered by a free tensor fascia lata (TFL) flap. In one of the cases the flap was transferred as a neurovascular free flap.
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