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Biomedical subjects

M Gulati

Publications and source records attributed to M Gulati.

At least 55 records · Page 3Linked to original sources
PubMed1994

Comparison of nuclear magnetic resonance spectroscopy with dual-photon absorptiometry and dual-energy X-ray absorptiometry in the measurement of thoracic vertebral bone mineral density: compressive force versus bone mineral.

31P nuclear magnetic resonance spectroscopy (NMRS) measurements were made on human T2 and T3 vertebral bodies. The bone mineral content (BMC) of isolated vertebral bodies minus the posterior elements and disks was measured using (1) NMRS on a 3.5 T, 85 mm bore GE Medical Systems NT-150 superconducting spectrometer, (2) a Lunar Corporation DPX-L dual-energy X-ray absorptiometry (DXA) scanner in an anterior-posterior (AP) orientation, (3) a Norland Corporation XR26 DXA scanner, also in an AP direction, and (4) a Norland Corporation model 2600 dual-photon absorptiometry (DPA) densitometer in both the AP and superior-inferior (SI) directions. Vertebral body volumes were measured using a water displacement technique to determine volume bone mineral densities (VBMD). They were then compressed to failure using an electrohydraulic testing device, followed by ashing in a muffle furnace at 700 degrees C for 18 h. Correlations of BMC between NMRS and DPA, DXA and ashing were excellent (0.96 < or = r < or = 0.99); in a one-way analysis of variance (ANOVA) test, means were not statistically different at a p level of 0.757. The correlations of VBMD between NMRS and the other methods were not as good (0.83 < or = r < or = 0.95); in a one-way ANOVA test, means were not statistically different at a p level of 0.089. BMC was a better predictor of ultimate compressive failure than VBMD for all six methods. For NMRS, the regression coefficient for BMC was r2 = 0.806, compared with r2 = 0.505 for VBMD. NMRS may prove an alternative to present methods of determining bone mineral.

Absorptiometry, Photon↗
PubMed1990

Ultrasound in obstructive jaundice.

One hundred and twenty-five consecutive patients with obstructive jaundice were prospectively studied by ultrasonography to determine the level and cause of obstruction. These were diagnosed precisely in 80 (72%) and 52 patients (41.6%) respectively. The results were compared with cholangiography. The final diagnosis was established at surgery (97 cases) and fine needle aspiration cytology (28 cases). While US is an excellent screening modality in distinguishing obstructive and non-obstructive jaundice, cholangiography is still the gold standard for determining the precise anatomic level and cause of obstruction.

Adult↗
PubMedDate not supplied

Ultrasound-guided percutaneous nephrostomy in non-dilated pelvicaliceal system.

Percutaneous placement of nephrostomy catheters in patients with non-dilated pelvicaliceal systems remains problematic. We successfully performed ultrasound-guided percutaneous nephrostomies in 5 such patients after intravenous administration of a diuretic agent. Diuresis resulted in transient dilatation of the calyces, facilitating the procedures, which were performed under real-time sonographic guidance using the Seldinger technique. No complications were encountered.

Child↗
PubMedDate not supplied

Sonographically guided fine-needle aspiration biopsy of lytic lesions of the spine: technique and indications.

PURPOSE: We report the use of sonography to guide fine-needle aspiration biopsies (FNABs) of lytic lesions of the spine. METHODS: Twenty-nine patients with lytic vertebral lesions with or without associated extraosseous soft-tissue extension underwent sonographically guided FNAB. Twelve cervical, 7 thoracic, 7 lumbar, and 3 sacral lesions were biopsied. Tissue samples were taken from either the bony lesion through a break in the cortex (n = 9) or the associated soft-tissue extension (n = 20). RESULTS: Adequate diagnostic material obtained in 27 cases (93%) revealed an inflammatory (n = 13) or malignant process (n = 14). Of the 2 patients with inconclusive FNAB findings, 1 patient was lost to follow-up, and the other underwent surgery, which revealed tuberculosis. No complications of FNAB were encountered. CONCLUSIONS: We conclude that sonography is a safe and effective guidance modality for FNAB of lytic lesions of the spine, especially for lesions in the cervical region. In the thoracic, lumbar, and sacral regions, however, the role of sonographically guided FNAB is limited to lesions affecting the posterior elements.

Adolescent↗
PubMedDate not supplied

Development of liposomal amphotericin B formulation.

A considerable effort has been spent in the past three decades to investigate various aspects of liposomes as novel drug delivery systems. In 1990, the first amphotericin B (AmB) liposomal preparation (L-AmB) under the brand name AmBisome was introduced into the market by Vestar. The successful marketing of the product moved liposomes out of the stage of experimental obscurity to the realistic stage of clinical utility. The launch of AmBisome sparked off the introduction of other lipid-based AmB products marketed by Liposome Technology (Amphocil) and The Liposome Co. (Abelcet). The drive behind the development of a modified formulation of AmB was to improve the therapeutic index of this drug with respect to its major drawback associated with both acute and chronic toxic effects. In a 30-year-long experience with AmB, several reports were recorded in the literature of acute adverse effects, such as fever, rigors, vomiting, cardiotoxicity and hypotension occurring during infusion; while long-term therapy was reported to be associated with hypokalemia, renal dysfunction and hematological abnormalities. Another serious problem encountered with the drug had been the poor response obtained in immunocompromised patients like those with AIDS, neutropenia and cancer patients on chemotherapy. The encapsulation of amphotericin B in liposomal vesicles was hence targeted not only to obtain an improvement in the therapeutic index but also to see if it was useful in eradicating deep-seated fungal infections in immunocompromised patients. The liposomal AmB was found to have a better therapeutic index and lower toxicity than the commercial AmB preparations. The LD50 of AmBisome in mouse was 175 mg/kg compared with 3.7 mg/kg for Fungizone, the commercial preparation of AmB. Additionally, L-AmB has prolonged circulation time, and extravasates into the site of infection and delivers the drug directly to the site, with no nephrotoxicity and neurotoxicity as experienced with AmB. This review traces the course of development of L-AmB and discusses the rationale behind the development of its liposomal preparation. The results in in vitro, in vivo and clinical studies, mechanism of action, biodistribution, and formulation considerations of L-AmB are described. The clinical experience with the marketed preparation is reviewed.

Amphotericin B↗
PubMedDate not supplied

Study of azathioprine encapsulation into liposomes.

The factors influencing the encapsulation of azathioprine (AZA) into liposomes were investigated to find out the conditions for its optimal entrapment. Similar studies for comparison were also carried out on 6-mercaptopurine (6-MP), of which AZA is a prodrug. AZA and also 6-MP show higher encapsulation efficiencies in MLVs as compared to LUVs. Variation in phospholipid composition does not seem to affect the loading capacity of either of the two drugs. The encapsulation efficiency of both the drugs improves upon addition of cholesterol in the bilayer, but the effect is seen only up to 30% cholesterol. Thereafter the effect becomes constant. AZA shows better incorporation in the positively charged liposomes as compared to those with neutral or negative charge. The entrapment of 6-MP is, however, found to be independent of the charge on the liposomes. Entrapment efficiency for both the drugs markedly depends on the pH of the hydration medium, yielding better entrapment efficiencies at high pH values. The rise in solute concentration initially causes increase in the entrapment of the two drugs which is followed by a decreasing phase.

Antimetabolites, Antineoplastic↗
PubMedDate not supplied

Mucoepidermoid carcinoma of the bronchus: is conservative surgery always justified?

A case of mucoepidermoid carcinoma of the bronchus in a 7-year-old boy is reported. The patient underwent right pneumonectomy. Histologically, the tumor was a low-grade muco-epidermoid carcinoma arising from the bronchus with lymph node metastasis in the drainage area. Presence of lymph node metastasis in this low-grade tumor suggests the possibility of early progression of disease in what has until now been considered a very slow growing tumor. Aggressive surgery may be necessary in these situations.

Bronchial Neoplasms↗
PubMedDate not supplied

Clinical profile, diagnosis and management of patients presenting with symptomatic pulmonary embolism.

OBJECTIVE: To study the clinical profile and diagnostic methods in patients with symptomatic pulmonary embolism (PE). METHODS: Prospective assessment of clinical features, radiology and outcome of patients presenting with symptomatic PE over an 18-month period. RESULTS: During study period, 24 patients with a mean age of 39 +/- 12.1 years were diagnosed to have symptomatic pulmonary embolism. Dyspnoea (91.7%) and cough (58.3%) were the predominant complaints. Spiral computed tomographic pulmonary angiography (CTPA) was performed in 21 (87.5%) patients and perfusion scans in 14 (58.4%) patients. Echocardiography performed in all patients revealed evidence of pulmonary artery hypertension and right ventricular dyskinesia in 20 (83.3%) and 15 (62.5%) patients, respectively. Thrombolysis with streptokinase was performed in 14 (58.3%) patients. All patients received low molecular weight heparin followed by warfarin. Of the 24 patients, 20 (83.3%) were discharged and are under regular follow-up; four patients died. CONCLUSIONS: Pulmonary embolism is a common problem and can be easily diagnosed provided it is clinically suspected. Early diagnosis and aggressive management is the key to successful outcome.

Adult↗
PubMedDate not supplied

Ultrasound guided aspiration biopsy of peripheral pulmonary lesions.

Forty-six patients with peripheral lung lesions underwent ultrasound-guided percutaneous needle aspiration biopsy. Aspirates were sent for cytological and/or microbiological examination. Confirmative diagnosis was obtained in 40 patients (86.9%). Twenty-eight patients had positive cytology for malignancy and 12 patients with benign lesions had diagnosis made by cytologic and microbiologic examination. None of the lesions could be diagnosed by sputum cytology and fibreoptic bronchoscopy with biopsy or brushings. No complication was observed in any patient. We conclude that ultrasound guided aspiration biopsy is a useful and safe method for the diagnosis of peripheral pulmonary masses. The diagnostic yield far exceeds that which can be obtained by sputum cytology and fibreoptic bronchoscopy with biopsy.

Adolescent↗
PubMedDate not supplied

CT manifestations of tubercular mediastinal lymphadenopathy.

A retrospective analysis was done of computerized tomographic (CT) scans of 29 patients with image guided histologically proven mediastinal tubercular lymphadenitis. Amongst these 19 patients were males while 10 were females in the age range of 2-65 years. Plain radiographs of all the patients revealed mediastinal lymphadenopathy. There was a high incidence of involvement of right paratracheal and tracheobronchial lymph nodes. The lymph nodes larger than 2 cm showed central low density area with peripheral enhancing walls. However, nodes less than 2 cm in size were mostly homogenous.

Adolescent↗
PubMedDate not supplied

Fluoroscopic transbronchial fine needle aspiration for diagnosis of peripheral pulmonary nodules.

Transbronchial fine needle aspiration (TBNA) was performed under fluoroscopic guidance in 21 patients with either solitary (15 patients) or multiple (6 patients) peripherally located nodules. Good aspirate could be obtained in 16 patients (76.1%). Ten were confirmed to be malignant and 2 turned out to be tubercular. Nonspecific benign inflammatory aspirate was obtained in the other four. There were no significant complications. TBNA is thus an effective, safe and quick method for diagnosis of solitary/multiple pulmonary nodules.

Adult↗