Biomedical subjects
D Patel
Publications and source records attributed to D Patel.
Superior lateral-medical approach to arthroscopic meniscectomy.
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Isokinetic and functional evaluation of the knee following arthroscopic surgery.
Surgery for internal derangement of the knee has been performed for functional disability. Arthroscopic surgery offers improved function sooner than conventional knee surgery. In three groups of patients, no complications occurred, convalescence was markedly decreased, and expedient limb function was achieved. Postoperative morbidity, i.e., increased edema, loss of motion and muscle inhibition, appeared much less than reports indicate with conventional open surgery. Conventional knee surgery was not compared with arthroscopic surgery because the author stopped performing conventional knee surgery. These date confirm the viability of arthroscopic surgery to achieve early restoration of function for a variety of knee disorders.
Effect of tetramethylammonium ion on the helix-to-coil transition of poly(deoxyadenylylthymidine): a nuclear magnetic resonance and calorimetric investigation.
Differential scanning calorimetry, temperature-dependent NMR, and UV spectroscopy are used to investigate the helix-to-coil transition of poly(deoxyadenylylthymidine) [poly(dA-dT)] in 1 M NaCl and 1 M Me4NCl (tetramethylammonium chloride). All three methods reveal that the polymer has a melting temperature, tm, that is approximately 6 degree C higher in 1 M Me4NCl than in 1 M NaCl. The NMR data show that this increased stability does not result from fundamental changes in base stacking or base pairing in going from 1 M NaCl to 1 M Me4NCl. Consistent with this observation, the calorimetric measurements yield essentially equal enthalpies for the helix-to-coil transition under the two salt conditions (6.8 kcal per base pair in 1 M NaCl and 7.0 kcal per base pair in M Me4NCl). Analysis of the shapes of the calorimetric curves shows that the transition is more cooperative in Me4NCl than in NaCl. Comparison of the calorimetric and van't Hoff enthalpies allows specification of the size of the cooperative unit: 27 base pairs in 1 M NaCl and 32 base pairs in 1 M Me4NCl. The NMR data reveal that the major Me4NCl-induced structural alterations (relative to NaCl) are a change in one glycosidic torison angle and a partial resolution of the two phosphates. The calorimetric experiments indicate that in the absence of fortuitous compensation these conformational changes are not accompanied by a significant enthalpy effect. On the basis of these data, we suggest that in 1 M NaCl poly(dA-dT) assumes predominantly a B-DNA-like conformation where the symmetry repeat occurs every base pair. By contrast, in 1 M Me4NCl the predominant conformation exhibits a dinucleotide repeat consistent with a right-handed alternating B-DNA structure.
Comparison of radionuclide brain scan and computerized tomography for the detection of intracranial infections.
The findings of radionuclide brain scans are computerized tomography (CT) were compared in 25 consecutive patients with intracranial infectious disease. Seventeen of the 25 patients had diffuse disease and eight had brain abscesses. The radionuclide scans showed abnormalities in 13 of the 17 patients with diffuse inflammatory disease, whereas th CT scans showed abnormalities compatible with inflammatory disease in five. All eight abscesses were demonstrated on the radionuclide scans, whereas the CT scans indicated abnormalities in seven cases. The authors conclude that the radionuclide brain scan is more sensitive than the CT scan for the demonstration of diffuse intracranial infectious disease.
Chromosome abnormalities in Down's syndrome patients with acute leukemia.
Chromosome and cytologic studies were performed on three Down's syndrome (DS) patients with acute nonlymphocytic leukemia (ANLL). All three patients had an aneuploid clone in their leukemic cells: 50, XX, +6, +19, +21, +22, +8, XX, +21, and 47,XY, +8, - 21 +dic(21;21)(p13;p11). Every patient appeared to have acute undifferentiated leukemia when the blast cells were examined with Wright-Giemsa stain; cytochemistry studies, however, showed that the leukemic blasts were in an early stage of myeloid differentiation. The two patients with +8 had a preleukemic phase; the blast cells of the patient with an extra no. 19 and no.22 could not be differentiated morphologically from those of the two patients with an extra no. 8. Our findings and a review of data on 40 other patients suggest that most DS children with ANLL have hyperdiploidy, which is usually related to gains of C, F, and /or G chromosomes, and that the abnormalities of +8 and of +19, +22 in DS children may be associated with acute leukemia (AL) in an early stage of myeloid differentiation.
Antibody response of the lactating sow to oral immunization with Escherichia coli.
Oral immunization of the lactating sow with live Escherichia coli (O8:K88) stimulated an IgA anti-K88 antibody response in mammary secretions and significantly enhanced the capacity of whey to inhibit adhesion of the inoculum E. coli strain to isolate pig enterocytes. An increase in agglutinating anti-O8 activity was also evident in jilk and was associated with both the IgA and IgM immunoglobulin classes. These results are consistent with the concept of a gut-mammary link, although measurement of specific antibody in the intestinal secretions of these animals suggested that there may be a difference in response duration at the two secretory sites. Prolonged oral administration of heat-killed organisms also stimulated specific antibody synthesis within the mammary gland, although the response, particularly to the O antigen, was both reduced and delayed in its appearance.
The immune response of mice to bacterial antigens given by mouth.
The secretory and systemic antibody responses to oral dead Escherichia coli were examined in A strain mice. The best responses were obtained in mice dosed with 1 x 10(10) bacteria. Orally immunized animals showed an enhanced response to subsequent parenteral immunization with somatic antigens. This effect could be passively transferred with serum. In contrast, the response to the capsular antigen K88 was reduced in the same animals.
The effect of hypotensive anesthesia on cephalothin concentrations in bone and muscle of patients undergoing total hip replacement.
Serial blood, muscle, and bone concentrations of cephalothin following intravenous infusion were determined in forty-eight patients during total hip replacement. Thirty patients received hypotensive anesthesia and the remaining eighteen received anesthesia without induced hypotension. The concentrations of cephalothin were determined during the first (early) and second (late) hours of the operation. Late serum levels were lower in the patients who had induced hypotension. In all patients at least one bone specimen contained measurable amounts of cephalothin. When pentolinium (Ansolysen) was used to induce hypotension, the late serum and early bone cephalothin concentrations were lower, while use of trimethaphan (Arfonad) did not appear to result in lower cephalothin concentrations in serum, muscle, or bone compared with patients with normotensive anesthesia.
Interesting images: liver scan in diagnosis of (Bochdalek's) diaphragmatic hernia.
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The Bankart procedure: a long-term end-result study.
Of 161 patients with 162 shoulders operated on during a thirty-year period (1946 to 1976), 124 were re-examined and twenty-one answered a questionnaire. The lesions found at surgery were separation of the capsule from the anterior glenoid rim in 85 per cent, a Hill-Sachs lesion of the humeral head in 77 per cent, and damage to the anterior glenoid rim (including fracture) in 73 per cent. There were five recurrences (3.5 per cent) after repair by the method described in the 145 shoulders that were followed. Only one of the forty-six patients with dislocation on the dominant side and one of the thirty-one with dislocation on the non-dominant side failed to return to the competitive athletic activities in which they participated prior to injury. The results at follow-up were rated excellent in 74 per cent, good in 23 per cent, and poor in 3 per cent. Ninety-eight per cent of the patients rated their result as excellent or good. Sixty-nine per cent of the shoulders had a full range of motion, and only 2 per cent of these shoulders redislocated. A fracture of the rim of the glenoid did not increase the risk of recurrence, while a moderate to severe Hill-Sachs lesion increased the risk only slightly. We concluded that with the meticulous technique of the Bankart repair as described, postoperative immobilization is not necessary, early return of motion and function can be expected, and resumption of athletic activities with no limitation of shoulder motion is possible for most patients.
Arterial embolization for radical tumor resection.
Two contemporary measures, selective transarterial embolization (Almgard et al. 1973) and controlled hypotensive anesthesia (Davis et al. 1974), have been combined in an effort to reduce the risk of operative bleeding in a case of massive bone and muscle resection of a highly vascular carcinoma lesion in the proximal third of the femur. This approach may be helpful in such cases.
5-Aminovaleric acid, a major free amino acid component of the anal sac secretion of the red fox, Vulpes vulpes.
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Pulmonary vasomotor tone during general anesthesia and deliberate hypotension in man.
Pulmonary and systemic hemodynamic responses to administration of pentolinium (0.3 mg/kg) were studied in eight patients undergoing total hip replacement during N2O-halothane anesthesia with PaCO2 maintained at 35-40 mm Hg. Measurements were made prior to induction of anesthesia; 20 minutes after induction; 45 minutes after induction but prior to pentolinium administration; 10, 20, and 60 minutes after administration of pentolinium; 15 minutes after AP recovered to within 10 per cent of baseline values. The reduction in AP produced by pentolinium was associated with significant decreases in both SVR and LVFP (estimated by measuring PA0 via a Swan-Ganz catheter). The profound and significant reductions in calculated PVR were more pronounced than those in SVR. Since PVR decreased in the face of reductions in both pulmonary arterial and left atrial pressures despite a significant increase (at 10 minutes) or no change (at 20 and 60 minutes) in pulmonary blood flow, the results suggest an active decrease in pulmonary vascular tone, presumably due to autonomic inhibition by pentolinium. Both LVSWI and RVSWI decreased significantly following injection of pentolinium. HR X SAP, an indirect index of MV02, decreased significantly following an initial increase at 10 minutes. Presumably these effects of pentolinium were conspicuous because N2O-halothane anesthesia altered the baseline of pulmonary vascular tone.
Gelatin implants in scleral buckling procedures.
The use of gelatin has been evaluated in a series of 59 retinal surgical procedures over a five-year period. When used as a "trapdoor" alone, we conclude that gelatin works as well as any of the currently employed materials for simple cases. The technique gave a 90% primary reattachment rate, which was increased to 100% reattachment by subsequent surgery or photocoagulation. It also gave a desirable absorbable feature in very anterior or very posterior lesions. Used as a meridional implant and combined with one or two layers of solid silicone, the gelatin has proved to be extremely useful in closing holes that were highly elevated or significantly "fish mouthing." We wish to emphasize the value of this use as a meridional implant combined with silicone in complex cases.
Significance of absent or faint kidney sign on bone scan.
Seven men, six suffering from widespread bone metastases of prostatic origin and one with urinary bladder carcinoma, demonstrated minimal or no discernible radioactivity in the kidneys and urinary bladder at the time of bone scanning using 99mTc-stannous polyphosphate. The mechanism behind this scan finding is thought to be rapid and enhanced uptake of the radiopharmaceutical by pathologic bone. The significance of the faint or absent kidney sign in bone scanning, particularly in cases where abnormally homogeneous and symmetric radioactivity exists, is discussed.