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Biomedical subjects

S Gupta

Publications and source records attributed to S Gupta.

At least 541 records · Page 30Linked to original sources
PubMed1999

Orbital mass lesions: US-guided fine-needle aspiration biopsy--experience in 37 patients.

PURPOSE: To evaluate the safety and effectiveness of using ultrasonographic (US) guidance for performing fine-needle aspiration biopsies of orbital mass lesions. MATERIALS AND METHODS: Thirty-seven patients with mass lesions in the orbit underwent US-guided fine-needle aspiration biopsy. Computed tomographic scans were available in all patients. In 19 patients, the lesions were located in posterior orbit, whereas in 18 patients the lesions were located in (n = 3) or extended up to (n = 15) the anterior compartment. Fine-needle aspiration biopsy was performed with 22-25-gauge needles and use of the freehand technique. RESULTS: Needle biopsies were performed safely and easily, and real-time US monitoring of the needle position was used to avoid injury to the eyeball. No major complications were encountered. Diagnostic specimens were obtained in 29 (78%) of the 37 patients, and 19 benign and 10 malignant disease processes were diagnosed. In eight patients (22%), an appropriate diagnosis could not be made, as aspiration samples yielded insufficient tissue. CONCLUSION: US provides safe and effective guidance for performing fine-needle aspiration biopsy in orbital mass lesions and is especially useful in deep-seated nonpalpable retrobulbar lesions.

Adolescent↗
PubMed1999

Transplanted hepatocytes proliferate differently after CCl4 treatment and hepatocyte growth factor infusion.

To understand regulation of transplanted hepatocyte proliferation in the normal liver, we used genetically marked rat or mouse cells. Hosts were subjected to liver injury by carbon tetrachloride (CCl4), to liver regeneration by a two-thirds partial hepatectomy, and to hepatocellular DNA synthesis by infusion of hepatocyte growth factor for comparative analysis. Transplanted hepatocytes were documented to integrate in periportal areas of the liver. In response to CCl4 treatments after cell transplantation, the transplanted hepatocyte mass increased incrementally, with the kinetics and magnitude of DNA synthesis being similar to those of host hepatocytes. In contrast, when cells were transplanted 24 h after CCl4 administration, transplanted hepatocytes appeared to be injured and most cells were rapidly cleared. When hepatocyte growth factor was infused into the portal circulation either subsequent to or before cell transplantation and engraftment, transplanted cell mass did not increase, although DNA synthesis rates increased in cultured primary hepatocytes as well as in intact mouse and rat livers. These data suggested that procedures causing selective ablation of host hepatocytes will be most effective in inducing transplanted cell proliferation in the normal liver. The number of transplanted hepatocytes was not increased in the liver by hepatocyte growth factor administration. Repopulation of the liver with genetically marked hepatocytes can provide effective reporters for studying liver growth control in the intact animal.

Animals↗
PubMed1999

Partial hepatectomy-induced polyploidy attenuates hepatocyte replication and activates cell aging events.

In understanding mechanisms of liver repopulation with transplanted hepatocytes, we studied the consequences of hepatic polyploidization in the two-thirds partial hepatectomy model of liver regeneration. Liver repopulation studies using genetically marked rodent hepatocytes showed that the number of previously transplanted hepatocytes did not increase in the liver with subsequential partial hepatectomy. In contrast, recipients undergoing partial hepatectomy before cells were transplanted showed proliferation in transplanted hepatocytes, with kinetics of DNA synthesis differing in transplanted and host hepatocytes. Also, partial hepatectomy caused multiple changes in the rat liver, including accumulation of polyploid hepatocytes along with prolonged depletion of diploid hepatocytes, as well as increased senescence-associated beta-galactosidase and p21 expression. Remnant hepatocytes in the partially hepatectomized liver showed increased autofluorescence and cytoplasmic complexity on flow cytometry, which are associated with lipofuscin accumulation during cell aging, and underwent apoptosis more frequently. Moreover, hepatocytes from the partially hepatectomized liver showed attenuated proliferative capacity in cell culture. These findings were compatible with decreased proliferative potential of hepatocytes experiencing partial hepatectomy compared with hepatocytes from the unperturbed liver. Attenuation of proliferative capacity and other changes in hepatocytes experiencing partial hepatectomy offer novel perspectives concerning liver regeneration in the context of cell ploidy.

Animals↗
PubMed1999

Lessons From Genetically Engineered Animal Models VI. Liver repopulation systems and study of pathophysiological mechanisms in animals.

The ability to localize transplanted hepatocytes in the liver offers exciting new opportunities. Transplanted hepatocytes enter liver plates, form hybrid plasma membrane structures with adjacent hepatocytes, express liver genes correctly, and survive indefinitely. The transplanted cell mass is regulated, such that cell proliferation is limited in the normal adult liver, whereas the liver is repopulated extensively when proliferation rates in transplanted and host hepatocytes become dissociated or host hepatocytes are ablated selectively. Transplanted hepatocytes are susceptible to hepatitis viruses. These aspects of transplanted hepatocyte biology indicate that liver repopulation systems can help address questions concerning pathophysiological mechanisms.

Animals↗
PubMed1999

Cerebral salt-wasting syndrome: does it exist?

Cerebral salt-wasting syndrome (CSWS) has been regarded as a misnomer of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). We take the position that CSWS does exist and might be more common than SIADH. Differentiation between groups has been difficult because of overlapping signs, symptoms, and associated diseases. Euvolemia in SIADH and hypovolemia in CSWS may be the only contrasting variables. However, clinical assessment of extracellular volume is accurate in about 50% of these patients. Determination of serum urate and fractional excretion rates of urate can differentiate one group from the other. In both groups, hyponatremia coexists with hypouricemia and increased fractional excretion of urate. When the hyponatremia is corrected by water restriction, hypouricemia and elevated FEurate correct in SIADH but persist in CSWS. Persistent hypouricemia and elevated FEurate were commonly noted with pulmonary and/or intracranial diseases. The absence of intracranial diseases in some patients suggests that renal salt wasting might be a more appropriate term than CSWS. A review of renal/CSWS reveals three studies involving hyponatremic neurosurgical patients who had decreased blood volume, decreased central venous pressure, and inappropriately high urinary sodium concentrations in the majority of them, suggesting that CSWS was more common than SIADH in neurosurgical patients. Evidence for the presence of a plasma natriuretic factor in CSWS is presented.

Animals↗
PubMed1999

Initial microbiologic studies did not affect outcome in adults hospitalized with community-acquired pneumonia.

Microbiologic studies (MBSs) fail to identify a specific pathogen in more than 50% of patients with community-acquired pneumonia (CAP). The 1993 American Thoracic Society guideline (ATS-GL) for the management of CAP advised selecting initial antibiotic regimens based on severity of illness and comorbidities. Our study evaluated the role of initial MBS in adult patients hospitalized with CAP and treated according to the ATS-GL. In 184 patients hospitalized at our facility for CAP in 1996, and treated according to the ATS-GL, 25 (14%) failed to respond to initial antibiotic regimens. In these nonresponders, there was no difference in mortality between those in whom antibiotics were changed empirically, and those with MBS-guided changes. We conclude that initial MBS may not be warranted in many adult patients admitted for CAP. Exceptions include patients with conditions that predispose to less common, more resistant pathogens.

Adolescent↗
PubMed1999

Computed tomography in abdominal tuberculosis.

The diagnosis of abdominal tuberculosis is often difficult because of its protean clinical manifestations and non-specific laboratory investigations. In the abdomen, tuberculosis may affect the intestinal tract, lymph nodes, peritoneum and solid viscera in varying combinations. CT, with its ability to provide a comprehensive overview of abdominal structures, is the imaging modality of choice for evaluation of such patients. This pictorial review illustrates the spectrum of CT appearances of abdominal tuberculosis which includes intestinal, lymph nodal, peritoneal, mesenteric, hepatic, splenic and pancreatic disease.

AIDS-Related Opportunistic Infections↗
PubMed1999

Ultrasound guided fine needle aspiration biopsy of splenic lesions.

Fine needle aspiration biopsy (FNAB) of focal splenic lesions has been infrequently utilized because of the risk of haemorrhage. This study was carried out to evaluate the safety and efficacy of ultrasound guided FNAB of splenic lesions. 35 patients with focal splenic lesions underwent FNAB under real-time ultrasound guidance using a free hand technique. Ultrasound findings were single or multiple focal hypoechoic lesions (n = 33), focal hyperechoic lesion (n = 1) and diffuse heterogeneous echotexture (n = 1). Aspirations were performed with 22 G spinal needles using either the subcostal or the intercostal approach. Definite cytological diagnosis was made in 22 patients (62.8%), including tuberculosis in 10 patients, lymphoma in seven patients, extramedullary haematopoiesis in two patients and aspergillosis, histoplasmosis and bacterial abscess in one patient each. FNAB was negative in 12 patients because the aspirates were either scanty or contained only blood. FNAB was falsely positive in one patient. Only one patient had significant intraabdominal bleeding, which was managed conservatively. In conclusion, splenic FNAB performed under ultrasound guidance is a safe and accurate method in the diagnosis of focal splenic lesions.

Adolescent↗
PubMed1999

Choices in pain management following thoracotomy.

Effective analgesia and blockade of the perioperative stress response may improve outcome and accelerate recovery following thoracic surgery. Although different approaches can achieve the same goal, it seems that a multimodal pain management based on the use of synergistic drugs provides better analgesia. The route of administration of the postoperative analgesic drugs is important, and epidural analgesia plays a role in the reduction of pulmonary complications.

Humans↗
PubMed1999

Simplified gene-fragment phage display system for epitope mapping.

We describe a simple and efficient system for epitope mapping by cloning random gene fragments into a specially designed gIIIp-based phage display vector. DNA encoding the antigen of interest is PCR-amplified and partially digested with DNaseI to generate 50-150-bp-long fragments, which are polished with T4 DNA polymerase and dephosphorylated. These fragments are cloned at the 5' end of the gIII after linearizing the vector with SmaI/SrfI, and the ligation is carried out in the presence of restriction enzyme SrfI. The restriction enzyme in the ligation reaction recuts the self-ligated vector but not the recombinants, since ligation with foreign fragments destroys the enzyme recognition site. Dephosphorylation of inserts prevents their chimerization and ensures ligation of single insert per vector molecule. Thus, using the above strategy, which prevents self-ligation of both the insert and the vector, the overall cloning efficiency and, thereby the library size, is improved more than 10-fold compared to the standard blunt-end, ligation-based methods for making similar libraries. The library is further enriched by a single-step infection of E. coli by phages obtained from primary transformants. This step eliminates all the phages that carry insert that are not in-frame with gIIIp and therefore do not display gIIIp. We have shown the utility of the above system in constructing a glutathione-S-transferase (GST) gene-fragment library in phages and identifying the epitope recognized by a monoclonal antibody against GST.

Amino Acid Sequence↗
PubMed1999

CT-guided fine-needle aspiration biopsy of spinal lesions.

PURPOSE: A retrospective study of CT-guided fine-needle aspiration biopsies (FNABs) of spinal lesions performed over a period of 6 years was carried out with the aim of assessing the safety and efficacy of the procedure and to analyse the various approaches used. MATERIAL AND METHODS: Ninety-three FNABs were performed in 87 patients, 4-70 years of age, under CT guidance. Lytic or mixed vertebral lesions with or without a paraspinal soft tissue component were included in the study. The approach depended on the anatomic region and part of the vertebra involved. RESULTS: A definite cytological diagnosis was obtained in 77 patients (88.5%); of these, 47 patients had benign lesions and 30 patients had neoplasms. The most common pathologies encountered were tuberculosis (n=33) and metastases (n=17). There were 10 inconclusive FNABs; these showed blood only, necrotic material or scanty material insufficient for diagnosis. There were no procedure-related complications. CONCLUSION: CT-guided FNAB is a safe and effective technique for the evaluation of spinal lesions and is helpful in planning therapy. Choosing the appropriate approach results in a low complication rate.

Adolescent↗
PubMed1999

Comparative evaluation of plain films, ultrasound and CT in the diagnosis of intestinal obstruction.

BACKGROUND: There are limited studies in the literature comparing plain radiography, US and CT in the evaluation of intestinal obstruction. We carried out this prospective study to compare the relative efficacies of these three imaging techniques in patients with intestinal obstruction. MATERIAL AND METHODS: Thirty-two patients presenting with clinical suspicion of intestinal obstruction were subjected to plain radiography, US and CT and the findings were compared with reference to the presence or absence of obstruction, the level of obstruction and the cause of obstruction. The final diagnosis was obtained by surgery (n=25), or by contrast studies and/or clinical follow-up in those who were treated conservatively (n=7). RESULTS: Out of 32 patients, 30 had mechanical intestinal obstruction (22 had small bowel obstruction and 8 had large bowel obstruction). Of the remaining 2 patients, 1 had adynamic ileus and the other had a mesenteric cyst. CT had high sensitivity (93%), specificity (100%) and accuracy (94%) in diagnosing the presence of obstruction. The comparable sensitivity, specificity and accuracy were, respectively. 83%, 100% and 84% for US and 77%, 50% and 75% for plain radiography. The level of obstruction was correctly predicted in 93% on CT, in 70% on US and in 60% on plain films. CT was superior (87%) to both US (23%) and plain radiography (7%) in determining the aetiology of obstruction. CONCLUSION: CT is a highly accurate method in the evaluation of intestinal obstruction especially for determining the level and cause of obstruction and should be the technique of choice when clinical or plain radiographic findings are equivocal.

Adolescent↗
PubMed1999

Ultrasound-guided fine needle aspiration biopsy of gall bladder malignancies.

PURPOSE: To establish the safety and efficacy of US-guided fine needle aspiration biopsy (FNAB) in gall bladder malignancies. MATERIAL AND METHODS: 142 patients suspected to have gall bladder malignancies underwent FNAB under real-time US guidance. The most common sonographic appearances were a mass filling or replacing the gall bladder (n=98), focal or diffuse wall thickening (n=25) and intraluminal polypoidal mass (n=19). FNAB was performed with a 0.7-mm spinal needle using a free-hand technique. RESULTS: On initial FNAB, 115 patients were diagnosed to have malignancy. In the remaining 27 patients, aspirates on first FNAB showed either inflammatory pathology (n=14) or the sample was suspicious of malignancy (n=7), or the aspirates were non-representative (n=6). Of these 27 patients, 13 underwent repeat FNAB because of the high suspicion of malignancy and 12 of them showed malignancy. The FNAB diagnosis of inflammatory disease of 7 patients was confirmed on subsequent surgery and 8 patients were lost to follow-up. Thus, a total of 127/142 were diagnosed to have gall bladder malignancy. Adenocarcinoma was the most common malignancy (89.76%). No procedure-related complications were encountered. CONCLUSION: US-guided FNAB is a safe and accurate technique to diagnose gall bladder malignancy. Either a repeat FNAB or surgical biopsy is recommended when the suspicion of malignancy is high and the initial FNAB is negative.

Adult↗
PubMed1999

CT of liver cysts in patients with autosomal dominant polycystic kidney disease.

PURPOSE: The purpose of this study was to illustrate the CT appearances of liver cysts in patients with autosomal dominant polycystic kidney disease (ADPKD). MATERIAL AND METHODS: Contrast-enhanced CT images of 24 patients with ADPKD were retrospectively evaluated for the presence, number, size and distribution of liver cysts. An attempt was made to categorize these cysts into peribiliary cysts (located adjacent to larger portal triads or in the hepatic hilum) and intrahepatic cysts (within the liver parenchyma but not in contact with larger portal triads). When it was not possible to definitely categorize the cysts into either type, the cysts were labeled as indeterminate. RESULTS: Liver cysts were seen in 13 (54%) patients. Intrahepatic cysts were seen in 12 patients, and were mainly peripheral in location with sizes ranging from less than 10 mm to 8 cm. Peribiliary cysts were seen in all 13 patients and were usually less than 10 mm in size. These cysts were seen as discrete cysts (8 patients), a string of cysts (10 patients), or as a tubular structure paralleling the portal vessels, mimicking biliary dilatation (11 patients). Twelve patients also showed indeterminate cysts which defied definite categorization into either type; two common causes of confusion included large (more than 10 mm) discrete cysts in the hilar region and the presence of a vessel adjacent to peripheral cysts. CONCLUSION: Liver cysts in patients with ADPKD show a wide variety of appearances on CT. Familiarity with these findings is essential to avoid confusion with other abnormalities.

Adult↗