Biomedical subjects
T K Chaudhuri
Publications and source records attributed to T K Chaudhuri.
Medical characteristics of 61 unwarranted malpractice claims.
We describe malpractice claims closed by plaintiff attorneys after initial medical expert (ME) review. This retrospective study includes 61 cases, of which 33 originated in hospitals, 18 in physicians' offices, and 10 in nursing homes. No claims were against state or federal agencies. The reviews were done between 1987 and 1994 for 29 attorneys from 11 states. The cases fell into 12 diagnostic groups, and leading causes for action were late diagnosis (13 cases), drug administration (11 cases), sepsis (6 cases), and strokes (5 cases). We conclude that internists are particularly liable to unwarranted malpractice claims when unexpected complications occur and when treatment fails to cure infectious disease. However, such claims may be terminated following the initial ME review.
Reporting "missed" radiologic diagnoses.
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Distribution of HLA antigens in Indian Gurkha population.
Fifty unrelated Indian Gurkha of Nepalese origin were studied to analyse the HLA antigen profile and their relation with other populations. Haplotype B35-Cw4 occurred with highest incidence and significant positive linkage disequilibrium in Gurkhas. Haplotype A10-B8 which occurs with the highest frequency in north Indians was also observed to occur with significant positive linkage in Gurkhas. HLA profile of Gurkhas thus may be the result of long-term isolation and genetic drift.
Human monoclonal antibody developed against ovarian cancer cell surface antigen.
BACKGROUND: Murine monoclonal antibodies (MoAb) potentially can be used in the radioimmunodetection and radioimmunotherapy of cancer. However, the administration of these radiopharmaceuticals to humans often leads to induction of human anti-murine antibodies (HAMA). HAMA has many disadvantages, which could decrease efficacy of the murine MoAb. The purpose of this work was to produce human monoclonal antibody against a human ovarian cancer cell surface antigen (OCCSA), which was not present in normal ovarian cells. This 200-kilodalton OCCSA also was used in the present study for characterizing the human monoclonal antibody. METHODS: Human monoclonal antibodies were produced in vitro by fusion of mutant myeloma cells, selected from GM1500, with human lymphoid cells immunized in vitro with purified OCCSA: The human monoclonal antibody was characterized using the following techniques: sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), native-PAGE, Western blotting followed by protein-A gold staining, immunodiffusion assays, and fluorescent antibody assays. RESULTS: Human monoclonal antibody, TC5 (immunoglobulin G1), was produced and purified. It was found to be specific for ovarian cancer, while also reacting with an early stage breast cancer. TC5 did not react with any normal (i.e., nonneoplastic) cells of the ovary, uterus, cervix, endocervix, or fallopian tube, nor did it react with normal lung, heart, pancreas, liver, or breast tissue. CONCLUSION: Human-human hybridomas produced human monoclonal antibody against OCCSA: The human monoclonal antibody, TC5, was specific for ovarian and breast cancer. TC5 did not react with any normal tissue tested. Future work will focus on the in vivo characterization of the human monoclonal antibody, after labeling with radionuclides.
Detection of ovarian cancer by 198Au-labeled human monoclonal antibody.
BACKGROUND: There is no reliable method for the early diagnosis of ovarian cancer. Radiolabeled monoclonal antibodies have potential to assist in early diagnosis, but they are limited by problems that include antibody specificity, stability, and immunoreactivity, as well as patient reactions to the antibodies used. METHODS: Methods were developed to 198Au-label a human monoclonal antibody (TC5 antibody), developed against an ovarian cancer cell surface antigen. Antigen binding sites on the TC5 antibody were protected with sepharose 4B affinity chromatography before 198Au-labeling. The 198Au-labeled TC5 antibody was evaluated with biopsy specimens in a blind study. The immunoreactivity of radiolabeled TC5 antibody also was evaluated in slot-blot experiments with extracts of the biopsy specimens. RESULTS: The 198Au-labeled TC5 antibody had high binding reaction to all biopsy specimens (six of six) pathologically diagnosed as ovarian cancer (serous and endometrioid adenocarcinoma). The radiolabeled TC5 antibody did not bind to any normal (non-neoplastic) specimens (zero in ten), with one exception. One "normal" ovary specimen had high binding of radiolabeled TC5 antibody, and metastatic ovarian cancer was diagnosed 4 months later. The TC5 antibody labeled with 198Au, without protecting antigen-binding sites, did not bind to any biopsy specimens. CONCLUSIONS: The affinity-labeling method was necessary to protect antigen-binding sites and preserve the immunoreactivity of the TC5 antibody. The 198Au-labeling method may be an ideal technique to evaluate monoclonal antibodies in vitro. The TC5 antibody had high sensitivity and specificity for detecting ovarian cancer.
Medical malpractice involving colon and rectal disease.
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Imaging studies for emphysematous pyelonephritis.
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Basic trypsin-subtilisin inhibitor from marine turtle egg white: hydrodynamic and inhibitory properties.
A basic trypsin-subtilisin inhibitor has been isolated from the egg white of marine turtle (Caretta caretta Linn.) and purified to homogeneity by gel filtration followed by ion-exchange chromatography. It has a single polypeptide chain of 117 amino acid residues, having a molecular weight of 13,600. It lacks methionine and tryptophan. Its isoelectric point is at pH 10.0 and the sedimentation coefficient (S20,w) value of 1.62 S is independent of protein concentration. It has a Stokes radius of 18.8 A, an intrinsic viscosity of 0.048 dl g-l and a diffusion coefficient of 10.17 x 10(-7) cm2 sec-1. Its fluorescence emission spectrum is similar to that of free tyrosine and the bimolecular quencing rate constant of its tyrosine residues with acrylamide is 3.15 x 10(9) M-1 sec-1. The inhibitor strongly inhibits both trypsin and subtilisin by forming enzyme-inhibitor complexes at a molar ratio of unity. The nature of inhibition toward both enzymes is not temporary. It has independent binding sites for inhibition of trypsin and subtilisin. Chemical modification with tetranitromethane suggests the presence of three tyrosine residues on the surface of the inhibitor molecule.
Double-blind placebo controlled randomized trial of indomethacin on urodynamic values measured by radionuclide imaging.
The effect of the prostaglandin synthetase inhibitor, indomethacin on urodynamic values measured by radionuclide imaging was studied in 17 men in a double-blind placebo controlled randomized trial. Measurements were made of voiding time, time for 50% emptying, average flow rate, ejection fraction, post-void residual urine volume, voided volume, and total bladder volume. Statistical analyses indicated no placebo-indomethacin differences between the two groups. Although prostaglandins are thought to contribute to the act of micturition by maintenance of bladder tone and contractility, our studies indicate that a standard dose of the prostaglandin inhibitor, indomethacin, did not affect the voiding component of bladder function. Patients need not discontinue prostaglandin inhibitors and other non-steroidal anti-inflammatory drugs with such effects prior to urodynamic testing.
Biplane transesophageal pacing echocardiography compared with dipyridamole thallium-201 single-photon emission computed tomography in detecting coronary artery disease.
TPE is a new diagnostic technique that uses simultaneous graded transesophageal left atrial pacing and biplane transesophageal echocardiography for the detection of pacing-induced wall motion abnormalities. In a prospective study 30 patients underwent biplane TPE, dipyridamole thallium-201 single-photon emission computed tomography (SPECT), and coronary arteriography. The sensitivity (86% vs 95%, p = not significant [NS]), specificity (89% vs 56%, p = NS), positive predictive value (95% vs 73%, p = NS), and negative predictive value (83% vs 83%, p = NS) of biplane TPE and thallium-201 SPECT in identifying patients with significant coronary artery disease was similar. In the 90 vascular territories analyzed, the agreement between biplane TPE and thallium-201 SPECT for presence or absence of significant disease was 71%. Analysis of the three major vascular territories demonstrated that each imaging modality had a high sensitivity and specificity in the left anterior descending and right coronary artery segments. However, the two techniques demonstrated poorly sensitivity in the segmental distribution of the circumflex coronary artery. In conclusion, biplane TPE compared favorably with thallium-201 SPECT in terms of safety and accuracy for detecting significant coronary artery disease. Accordingly, biplane TPE may be a suitable alternative for those patients with nondiagnostic thallium-201 SPECT studies and in those with contraindications to adenosine or dipyridamole.
Surface hydrophobicity of a low molecular weight basic trypsin subtilisin inhibitor from marine turtle eggwhite.
Surface hydrophobicity has recently been emphasized as an important parameter for functional correlation of proteins. However, evaluations of the parameter by different experimental techniques often do not correlate well with each other. In this paper we have compared surface hydrophobicity of a basic protein with those of beta-lactoglobulin, ovalbumin and lysozyme by fluorescence probe method using ANS as an external probe. Two different fluorimetric approaches to determining the surface hydrophobicity parameter, namely, the slope method and the binding parameter method, follow the same relative order. Denaturants, urea, and guanidine hydrochloride disrupted the hydrophobic clefts of the inhibitor on the surface, causing a drastic reduction of surface hydrophobicity.
Prognostic implication of gastroparesis in patients with diabetes mellitus.
The prognosis and survival in 13 patients with Type II diabetes mellitus who had delayed gastric emptying as shown by radionuclide tests performed between August 1985 and August 1987 was determined in July 1990. The two patients that were over 80 years of age died within 18 months of the diagnosis of diabetic gastroparesis, but ten of the remaining eleven patients survived. The clinical data on these patients suggest that despite the usual presence of significant co-existent pathology, gastroparesis diabeticorum carries a less ominous prognosis than currently believed.
Complementary role of radionuclide and CT scans in the diagnosis and management of emphysematous pyelonephritis.
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Serve the elderly as a medical expert.
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Risk management in suspected acute appendicitis.
Acute appendicitis is a disease in which the essential elements for timely diagnosis are available. These elements are a careful history and thorough physical examination, the latter repeated as necessary until clinical judgment indicates that exploratory surgery should be performed or the patient safely discharged. The hospital that does not provide its staff with facilities to do so invites a potentially successful malpractice claim. In the absence of properly documented care, such a claim could include allegations of improper or inadequate evaluation of a person presenting for medical care, negligent medical care based on failure to properly use referral and consultant sources, and failure to provide adequate follow-up (including hospital admission). Such allegations would describe the foreseeable and significant consequences of the adverse event, be it premature discharge or negative exploration. Risk management includes education of hospital administration about the importance of an adequate observation period in this diagnosis, and education of the professional staff about the need for thorough documentation of the serial examinations when surgery is deferred. This article has presented fact, references, and opinion, which should help hospital risk managers to assess the documentation of appendicitis cases now being seen in their hospital, to plan educational interventions with the administration and professional staff, and to assist the hospital collections personnel if payers contest admissions that did not result in surgery.
Correlation of radionuclide urodynamometric and clinical data in 20 men with urinary symptoms.
Radionuclide uroflowmetry was performed in 20 patients. These data were correlated with other urologic data, the treatment decision, and the patient's clinical status five to twelve months after testing. In 19 patients the follow-up period confirmed the expectations of the therapeutic plan. We conclude that the radionuclide uroflowmetry technique provides the urologist with objective data which can assist in the decision to perform surgery.