Biomedical subjects
Publications and source records attributed to P K Sharma.
Real-time intraoperative ultrasonography was used to detect and facilitate removal of an airgun pellet from the tongue of a 14-year-old boy. Diagnostic ultrasound was crucial in clarifying the positional relation between the foreign body and the instrument used, enabling safe, precise and rapid retrieval during a potentially hazardous surgical operation.
The release of iron from ferritin in the presence of benzene metabolites, viz. phenol (P), catechol (CT), hydroquinone (HQ) and superoxide radical generating compounds, viz. pyrogallol (PL), phloroglucinol (PG), phenylhydrazine (PH) or phenylenediamine (PD) was studied in acetate buffer, pH 5.6. Monitoring the formation of the iron-ferrozine complex quantitated the release of iron from ferritin. The presence of P (125 microM) did not result in the release of iron from ferritin, whereas the same concentration of CT, HQ, PL, PH or PD resulted in the release of significant amounts of iron from ferritin and a marginal amount of iron in the presence of PG, CT, HQ, PL, PH or PD concentration and time-dependent increase in iron release from ferritin were observed although the increase was not linear as a function of time and concentration of the compounds studied. The presence of superoxide dismutase inhibited significantly the release of iron from ferritin by CT, HQ, PL, PH or PD. The iron released from ferritin by CT, HQ, PL, PH or PD enhanced lipid peroxidation in rat brain homogenate and released aldehydic products from bleomycin-dependent degradation of DNA and also caused single strand nicks to pUC18 DNA. These studies indicate that CT and HQ, the two principal polyphenolic metabolites of benzene and PL, PH or PD, the superoxide radical generating compounds were capable of reducing ferric iron from ferritin and also mobilizing and releasing iron from ferritin core. The release of iron from ferritin by these compounds is a result of direct reduction of ferritin iron by electron transfer and also reduction via superoxide radical. The release of iron from ferritin by CT and HQ may have toxicological implications in relation to benzene toxicity. The release of iron by superoxide radical generating agents suggests that oxidative stress may play a role as this could lead to disruption of intracellular iron homeostasis.
A novel migration of the trimethylsilyl group during reaction of methoxy[(trimethylsilyl)ethoxy]carbene with N-phenylmaleimide (NPM) and with C(60), reported earlier, was examined by means of deuterium labeling of the carbene. For the NPM case it was found that the CD(2)CH(2)SiMe(3) group, initially bound to oxygen, became the CH(2)CD(2)SiMe(3) group bound to carbon in the end product. Not only had the trimethylsilylethyl group moved from oxygen to carbon, but the TMS group had also migrated 1,2 along the ethyl chain. For the C(60) case, complete scrambling of the CD(2) group was observed, strongly implying the involvement of a silacyclopropane carbocation responsible for product formation. The labeling study supports the mechanism that was tentatively advanced earlier for addition to NPM and one of the possibilities suggested for addition to C(60).
OBJECTIVE: To evaluate the feasibility and predictive ability of the sentinel node localization technique for patients with squamous cell carcinoma of the oral cavity or oropharynx and clinically negative necks. DESIGN: Prospective, efficacy study comparing the histopathologic status of the sentinel node with that of the remaining neck dissection specimen. SETTING: Tertiary referral center. PATIENTS: Patients with T1 or T2 disease and clinically negative necks were eligible for the study. Nine previously untreated patients with oral cavity or oropharyngeal squamous cell carcinoma were enrolled in the study. INTERVENTIONS: Unfiltered technetium Tc 99m sulfur colloid injections of the primary tumor and lymphoscintigraphy were performed on the day before surgery. Intraoperatively, the sentinel node(s) was localized with a gamma probe and removed after tumor resection and before neck dissection. MAIN OUTCOME MEASURES: The primary outcome was the negative predictive value of the histopathologic status of the sentinel node for predicting cervical metastases. RESULTS: Sentinel nodes were identified in 9 previously untreated patients. In 5 patients, there were no positive nodes. In 4 patients, the sentinel nodes were the only histopathologically positive nodes. In previously untreated patients, the sentinel node technique had a negative predictive value of 100% for cervical metastasis. CONCLUSIONS: Our preliminary investigation shows that sentinel node localization is technically feasible in head and neck surgery and is predictive of cervical metastasis. The sentinel node technique has the potential to decrease the number of neck dissections performed in clinically negative necks, thus reducing the associated morbidity for patients in this group.
Ring opened structures of C60 and C70 are shown to be stabilized by complexation with transition metal fragments of the form CnHnM, where n = 3 to 6 and M = Cr, Mn, Fe, Co, and Rh. The ring opening of C60 and C70 is compared with the reverse process of the well-known catalytic conversion of acetylene into benzene. Calculations at the semi-empirical PM3(tm) level show that the 6-membered ring in C60 and C70 can be opened up in different ways through complexation with transition metal fragment. The mode of ring opening depends on the number of external 5- and 6-membered rings around the 6-membered ring being cleaved. The structures and energetics of the various ring-opened structures are discussed.
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A 32 year-old woman developed generalised lichenoid eruptions on her body followed by diffuse loss of scalp hair of the anagen effluvium type. She was receiving several anti-tubercular drugs, including rifampicin, isonicotinic acid hydrazide (INH), pyrazinamide, and ethambutol, for abdominal tuberculosis. INH, which is a leading cause of drug eruptions in the above group of drugs was withdrawn. However, the other antitubercular drugs were continued along with 40 mg of prednisolone in a single daily morning dose. The latter was discontinued slowly over a period of 10 weeks. There was complete recovery of hair loss and the regrowth started after 12 weeks of alopecia. Such anagen effluvium with lichenoid eruption following INH therapy has not been observed previously. The complete recovery from anagen effluvium is difficult to explain, but it could have been because of the early initiation of corticosteroid.
Epidemiologic investigations revealed a 56.7 and 13.32% slide positivity rate in febrile and afebrile malaria cases, respectively. In both cases, Plasmodium falciparum was predominant. Anopheles culicifacies resistant to dichlorodiphenyltrichloroethane and benzene hexachloride (hexachlorocyclohexane) was found breeding profusely in pools and ponds created by excavation of earth around brick kiln in the region. Furthermore, children were not found to be producing significant levels of antibodies and a large percentage of patients harbored chloroquine-resistant parasites. Also, more than 1 P. falciparum strain was present in the population. We detected 2 strains, VI and VII, of which type VI was predominant.
A retrospective study of 1006 patients was undertaken to evaluate the benefit of a change of strategy in performing coronary artery by-pass grafting surgery. Group A consisted of 500 patients who were consecutively operated on cardiopulmonary by-pass and group B consisted of 506 patients who were consecutively operated on using "off pump" techniques. Pre-operative risk profile in both groups were similar as was as in the operating time. There was distinct benefit in amount of homologous transfusion, period of ICU stay, increased usage of radial artery conduit and improvement in transoesophageal echocardiography assessment of ischaemic mitral incompetence immediately after revascularisation in off pump (group B). Though there was a lower mortality in group B ie, 3/506 vis-a-vis 10/500 in group A this is not of statistical significance. Improvement in left ventricular ejection fraction >5.0% occurred more frequently in one month follow-up visits of group B patients. Period of return to active life was also shorter (28 versus 56 days). Based on observations, we conclude that there is a distinct benefit in avoiding cardiopulmonary by-pass while performing coronary artery by-pass grafting.
BACKGROUND: The study stemmed from an incidental observation of improvement in 2 patients with pityriasis rosea while receiving erythromycin. OBJECTIVE: The purpose of the study was to evaluate the efficacy of erythromycin in patients with pityriasis rosea. METHODS: A double-blind, placebo-controlled clinical study was performed in an outpatient setting in a major hospital. Ninety patients over a period of 2 years were alternatively assigned to treatment group or placebo group. Patients in the treatment group received erythromycin in divided doses for 14 days. The response was categorized as complete response, partial response, or no response. All patients were followed up for 6 weeks. RESULTS: Both groups were comparable with regard to age at presentation, sex, and average duration of disease at the time of reporting to the clinic. Upper respiratory tract infection before the appearance of skin lesions was reported in 68.8% of all patients. Complete response was observed in 33 patients (73.33%) in the treatment group and none in the placebo group (P <.0001). CONCLUSION: Oral erythromycin was effective in treating patients with pityriasis rosea.
OBJECTIVES: Parathyroid hormone-related protein (PTHrP) is expressed by squamous cell carcinomas. Our first objective was to examine the stability of PTHrP in normal human plasma. Our second objective was to determine whether plasma PTHrP could be used in patients with head and neck squamous cell carcinoma (HNSCC) as an indicator of tumor burden or relapse. STUDY DESIGN AND SETTING: Blood and urine samples from 55 HNSCC patients undergoing tumor resection at The Ohio State University were measured for plasma PTHrP (1-86) concentration, serum ionized calcium concentration, and urine calcium/creatinine ratio. RESULTS: Two of 55 HNSCC patients had detectable levels of plasma PTHrP. Serum ionized calcium concentrations and urinary calcium/creatinine ratios were within normal limits in all patients. CONCLUSIONS: Plasma PTHrP was not a valuable indicator of tumor presence or recurrence in our patient population. SIGNIFICANCE: Plasma PTHrP is not a useful marker of tumor presence or recurrence in patients with stage II to IV or recurrent HNSCC.
1,2-Di-O-acetyl-3-deoxy-3-trifluoromethyl-5-O-benzoyl-beta-D-ribofuranos e was synthesized from the precursor keto sugar by the use of Ruppert's reagent (CF3SiMe3) as the source of a nucleophilic trifluoromethyl group. Coupling of this trifluoromethyl sugar with nucleobases and elaboration gave novel deoxy and dideoxynucleosides. A single crystal X-ray analysis confirmed the structure and stereochemistry. The deoxynucleosides were converted through an elimination reaction to their dideoxydidehydro derivatives.
Heavy metal resistance by bacteria is a topic of much importance to the bioremediation of contaminated soils and sediments. We report here the isolation of a highly cadmium-resistant Klebsiella planticola strain, Cd-1, from reducing salt marsh sediments. The strain grows in up to 15 mM CdCl(2) under a wide range of NaCl concentrations and at acidic or neutral pH. In growth medium amended with thiosulfate, it precipitated significant amounts of cadmium sulfide (CdS), as confirmed by x-absorption spectroscopy. In comparison with various other strains tested, Cd-1 is superior for precipitating CdS in cultures containing thiosulfate. Thus, our results suggest that Cd-1 is a good candidate for the accelerated bioremediation of systems contaminated by high levels of cadmium.
Induction of nodABC genes of R. ciceri was studied by constructing nodABC-lacZ fusion. The root exudates of the homologous hosts induced the expression of nodABC genes but those of heterologous hosts failed to do so. The HPLC analysis of the root exudates of C. arietinum showed the presence of 6-7 compounds with retention times matching to flavonoids like naringenin, hesperetin, daidzein, naringin, 7 OH coumarin and luteolin. Induction studies using the standard flavonoids showed naringenin, followed by daidzein, as most potent inducer of the nodABC genes of R. ciceri. Naringenin in combination with daidzein showed a synergistic effect on the expression of nodABC genes.
Electrotransformation of Rhizobium leguminosarum was successfully carried out with a 15.1-kb plasmid, pMP154 (Cmr), containing a nodABC-lacZ fusion by electroporation. The maximum transformation efficiency, 10(8) transformants/microg of DNA, was achieved at a field strength of 14 kV/cm with a pulse of 7.3 ms (186 Omega). The number of transformants was found to increase with increasing cell density, with no sign of saturation. In relation to DNA dosage, the maximum transformation efficiency (5.8 x 10(8) transformants/microg of DNA) was obtained with 0.5 microg of DNA/ml of cell suspension, and a further increase in the DNA concentration resulted in a decline in transformation efficiency.
OBJECTIVE: To evaluate complications and sequelae of maxillary removal and reinsertion for anterior cranial base tumors. DESIGN: A retrospective review of patients who underwent maxillary removal and reinsertion from 1990 to 1996. SETTING: The Arthur G. James Cancer Hospital and Research Institute at The Ohio State University, Columbus. PATIENTS: A consecutive sample of 46 patients who underwent maxillary removal and reinsertion. The patients ranged in age from 11 to 77 years and were followed up for as long as 6 years after surgery. There were 16 benign and 30 malignant lesions. MAIN OUTCOME MEASURES: Intraoperative, postoperative (1-10 days), short-term (11 days through 3 months), and long-term (>3 months) complications; survival status of patients; and adjuvant therapy. RESULTS: Four patients (9%) had undergone previous radiotherapy; 9 (20%) received intraoperative radiation therapy; and 23 (50%) received planned postoperative radiotherapy. No intraoperative complications were noted. The most common short-term complication found was transient diplopia, affecting 9 patients (20%). Diplopia resolved within 3 months in all but 2 patients, in whom the condition was permanent. There were 4 patients (9%) who required removal of the nasal dorsum plate, and 4 (9%) who required removal of maxillary plates that were exposed intranasally. Midface asymmetry as reported by the patient or noted on the physical examination was documented in only 2 patients. The most common long-term complication was nasal asymmetry, affecting 13 patients (28%). CONCLUSIONS: Maxillary removal allows improved visualization and access to anterior skull base lesions, while reinsertion of the maxillary fragment provides functional preservation and excellent cosmesis with few short- or long-term complications, even when adjuvant radiotherapy is used.
OBJECTIVES: To describe an approach based on initial tissue-conserving surgery used to obtain histologically determined prognostic information that has therapeutic implications and the potential to enhance preservation of function. STUDY DESIGN: Analysis of a group of patients with head and neck cancer treated initially with tissue-conserving surgery based on Mohs' histographic sectioning and selected neck dissection to derive histologically determined prognostic information with therapeutic implications and preservation in function. METHODS: This study is primarily based on an analysis of patients from January 1, 1989, through June 4, 1996 assigned to a protocol evaluating resection of oral cavity squamous cell cancer with margin control using Mohs' histographic technique and/or a group of patients with neck assessment of NO on clinical examination who are undergoing supraomohyoid neck dissections. RESULTS: Thirty-three primary tumor resections were performed using the Mohs' technique, and 54% required two or more Mohs' sections before clear histologic margins were obtained following resection based on clinically determined negative margins. There were 44 patients who underwent unilateral or bilateral supraomohyoid neck dissections, and 33% had occult, histologically positive nodes. When compared with the disease of the neck specimens, a preoperative computed tomography scan had a sensitivity of 25%, a specificity of 77%, and an accuracy of 63%. CONCLUSIONS: This report describes the effectiveness of Mohs' histographic sectioning and selective neck dissection as a means of determining prognostic information that can be used to develop a focused and cost-effective treatment program that, along with contemporary reconstructive techniques, provides a potential enhancement of function preservation.
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