Biomedical subjects
Publications and source records attributed to S Saini.
Four volunteers were imaged with echo-planar imaging before and after ingesting a dilute barium preparation. The contrast material improved bowel visibility by increasing lumen signal intensity, without increasing noise. Long T2 gastrointestinal contrast material can be used in T2-weighted imaging when motion artifacts are suppressed by ultrashort acquisitions.
A computer program was evaluated as a tool for increasing the diagnostic acumen of medical housestaff and students in identifying acid-base disorders. The participants were randomized into two groups; group A (N = 20) was encouraged to use the software, and group B (N = 19) was denied access. Pre- and post-tests were administered to delineate the groups' ability to identify correctly an acid-base disorder from laboratory data (electrolytes and arterial blood gas). During 6 weeks, group A used the computer for a mean of 2.83 h (range 1 to 6). The mean +/- SE number of correct answers out of 20 questions, prior to use of the computer program, were 5.7 +/- 0.8 (95% confidence interval 3.9 to 7.5) for group A and 5.2 +/- 0.6 (95% confidence interval 3.9 to 6.5) for group B. These results were not statistically different. Correct responses increased significantly in group A to 10.3 +/- 0.9 (P < 0.0001, 95% confidence interval 8.4 to 12.2) but did not increase significantly in group B. The data suggest that this software program was effective in increasing the diagnostic capabilities of medical housestaff and students for identifying acid-base disorders.
Expandable metallic stents were placed in 34 patients with pathologically proved malignant bile duct obstruction to determine ease of insertion, benefits of a one-stage insertion, and cost-effectiveness relative to conventional plastic stents. Thirty-eight strictures, ranging in length from 1 to 7 cm (mean, 3.2 cm), were present in the 34 patients. Strictures were located in the lower common bile duct (n = 22), middle of the common bile duct (n = 6), and hilar confluence (n = 10). In 13 patients (38%) metallic stents were placed at the time of initial biliary drainage (one-stage procedure), while the remaining patients underwent stent placement within 1-7 days of biliary drainage (two-stage procedure). Biliary obstruction was relieved in 31 of 34 patients (91%). Three patients died within 14 days of stent insertion of unrelated causes, without any change in biliary status. Mean duration of follow-up for all patients was 5.3 months (range, 0.5-14 months). Four episodes of stent occlusion occurred in three patients (12% occlusion rate); each episode was treated successfully. The average length of hospital stay for patients who underwent a one-stage procedure was 13 days (range, 3-33 days) and was 20 days (range, 9-42 days) for patients who underwent a two-stage procedure. The facility of one-step insertion, low occlusion rate, and the many strategies available for treatment of occluded stents make metallic stents an attractive alternative to conventional plastic stents in palliating patients with malignant biliary obstruction.
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Bacterial overgrowth in the upper small intestine is postulated to cause persistent diarrhea. We compared the fecal and upper intestinal flora in 82 patients with persistent diarrhea aged < or = 36 months and weight-for-length < or = 90% of National Center for Health Statistics standards (NCHS) and 39 non-diarrheal children with age < or = 36 months, nutritionally matched with the patients and residing in the same environment. In the age groups < or = 12 months and > 12 months the duodenal fluid bacterial counts > or = 10(5)/ml were found with similar frequency in patients and controls for aerobic (p = 0.33; p = 0.1) and anaerobic (p = 1.0; p = 1.0) bacteria. However, the duodenal isolation rates of any aerobic bacteria (p < 0.05) without regard to counts and Enterobacteriaceae (p = 0.06) were higher in patients than in controls. Colonization with Enterobacteriaceae was directly correlated with increased stool weight over a 7-day observation period (p < 0.05; p < 0.01). One or more pathogens were isolated in the feces of 58% of the patients and 43.8% of the controls. Enteroadherent E. coli of the localized [EAEC-L] (p < 0.01) and aggregative [EAggEC] (p = 0.22) phenotypes were isolated more commonly from the feces of patients. The duodenal fluid detection rates for Klebsiella were significantly greater (p < 0.01) in patients, while Giardia lamblia was detected more commonly in the duodenal fluid of controls (p < 0.01). The presence of specific pathogens in the feces did not seem to be related to the extent of small bowel colonization.(ABSTRACT TRUNCATED AT 250 WORDS)
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Recent technical advances in echo-planar magnetic resonance (MR) imaging prompted an investigation of these new techniques in pancreatic MR imaging and evaluation of bowel lumen enhancement with an aqueous bowel contrast agent. In 42 subjects (36 healthy, six with pancreatic disease), various T1-weighted inversion-recovery and T2-weighted spin-echo fat-suppressed pulse sequences were assessed with an echo-planar technique implemented with a modified clinical MR imager. Single-excitation imaging (echo time, 26 msec) provided a higher (P less than .05) signal-to-noise ratio than did conventional spin-echo and all other echo-planar techniques. In 13 (72%) of 18 healthy subjects who did not undergo administration of the contrast agent, the entire pancreas was distinguished from adjoining bowel. In all 18 subjects who underwent contrast-enhanced imaging, a significantly greater (P less than .05) intraluminal signal intensity was apparent with all echo-planar pulse sequences and the entire pancreas was identified. In six patients with pancreatic disease, lesions could be identified by their difference in signal intensity.
The diagnostic performance of high-field-strength magnetic resonance (MR) imaging (1.5 T) for detection of liver metastases was compared with that of computed tomography (CT). All patients (n = 52) underwent preoperative screening for metastases by means of MR imaging with T1-weighted, proton-density-weighted, and T2-weighted pulse sequences and CT scanning with unenhanced, incremental dynamic bolus-enhanced, and delayed contrast medium-enhanced techniques. Diagnostic performance was evaluated by means of receiver operating characteristic analysis in which 800 images (400 with and 400 without lesions) and five readers (4,000 observations) were used; images were obtained from patients (n = 39) in whom the same anatomic levels were available for all MR imaging and CT studies. Direct comparison between the best MR imaging technique (T2-weighted spin-echo imaging [repetition time, 2,000 msec; echo time, 70 msec]) and the best CT technique (incremental dynamic bolus CT) showed a strong trend of superiority of T2-weighted MR imaging over incremental dynamic bolus CT. No highly statistically significant difference (P greater than or equal to .01), however, was found between these two techniques.
Computed tomographic (CT) scans in 30 patients who had undergone percutaneous drainage for acute complicated pancreatitis were retrospectively studied to determine the role of percutaneous drainage. Fifty-nine collections were percutaneously drained in these 30 patients. Eighty-one catheters were placed in the 59 collections (average, 1.4 catheters per patient). Patients required an average of three catheter manipulations, seven abdominal CT scans, 5 weeks of catheter drainage, a mean hospital stay of 82 days (range, 42-122 days), and a mean intensive care unit stay of 31 days (range, 1-62 days). Percutaneous intervention was successful in 14 patients, partially successful in four, and unsuccessful in eight. A temporizing effect was seen in four patients. Percutaneous intervention was successful in one of 10 central (pancreas and lesser sac areas) collections and 28 of 49 peripheral collections. Surgical debridement was necessary in 16 patients because of failed or incomplete percutaneous drainage. Complications occurred in five patients, and the mortality rate was 33%. Drainage of central areas should initially be performed by a surgeon, while peripheral collections should be drained percutaneously as they develop.
Levels of tissue carcinoembryonic antigen (CEA) in 54 abdominal fine-needle biopsy specimens from 50 patients were measured to ascertain the use of tissue CEA levels in diagnosis of malignancy. Biopsy was performed in the following sites: liver (n = 34), retroperitoneum (n = 8), adrenal gland (n = 3), pancreas (n = 2), omentum (n = 2), pelvis (n = 2), spleen (n = 2), and stomach (n = 1). Histologic findings proved malignancy in 39 patients and benign disease in 11 patients. In these 11 patients, the mean levels of tissue CEA were lower than the normal level of serum CEA (3 ng/mL). Tissue CEA levels were higher than serum CEA levels in nine patients with colonic carcinoma and in 12 of 16 patients with noncolonic CEA-secreting malignancies. Four patients with noncolonic CEA-secreting malignancies had tissue CEA levels within the normal range (less than 3 ng/mL). Tissue CEA levels were also normal in 13 patients with various non-CEA-secreting tumors. Tissue CEA levels may prove useful in biopsy of necrotic or cystic lesions and assessment of response to ablative therapy for colon metastases.
Image quality and safety of magnetic resonance (MR) imaging were evaluated in vitro and in eight patients with the most commonly employed metallic biliary endoprosthesis. In vitro, the stent produced no tip deflection at 0.6 or 1.5 T. Trace magnetic susceptibility artifact, similar to artifact from a column of air, paralleled the stent. In patients, image degradation was minimal with conventional pulse sequences. Middle-field-strength spin-echo images revealed minimal artifacts indistinguishable from those produced by pneumobilia.
Pleural sclerosis after drainage with a small-bore catheter was performed in 21 patients with malignant pleural effusions. Intrapleural catheters 7- to 24-French in size were placed by using sonographic guidance. Tetracycline (18 patients) and bleomycin (four patients) were used as sclerosing agents (one patient had both). Clinical and radiologic follow-up was available on all patients until they died (range, 2 weeks to 25 months; mean, 3.6 months). Pleural sclerosis was successful in 15 (71%) of 21 patients. Two patients in whom pleurodesis failed had pleural sclerosis repeated, with one success and one failure. All of the failures were in patients in whom the amount of chest-tube drainage was more than 100 ml/day. Pleurodesis with tetracycline was painful in six patients; no pain was associated with use of bleomycin. Small pneumothoraces developed in four patients at the time of chest-tube placement, without consequence. A superimposed infection that developed in a patient having continuous drainage of pleural fluid was successfully treated with antibiotics. Pleural sclerotherapy can be performed through sonographically placed small-bore catheters with results comparable to those seen with large-bore, surgically placed catheters.
We used a pulsed tunable dye laser (operating at 60 mJ per pulse, 504-nm wavelength) to fragment large (0.8-4.5 cm) stones retained in the hepatic ducts or common bile duct in 12 patients after cholecystectomy. Attempts to extract stones via a T-tube or endoscope had been unsuccessful in all patients. In nine of 12 patients, all stone fragments were successfully eliminated during the initial treatment. In one patient, fragmentation occurred but debris remained, requiring endoscopic stenting. Pseudomonas sepsis developed in this patient 30 days after the procedure and was treated by extraction of the stone fragments. Fragments remaining after lithotripsy were cleared at the same sitting by using saline flushing or endoscopic or percutaneous basket extraction. In two of 12 patients, the treatment was unsuccessful because of laser malfunction. The treatment was performed without complications, except for clinically insignificant hyperamylasemia, which occurred in two patients. Our experience suggests that laser lithotripsy offers a safe alternative for nonsurgical treatment of large retained biliary stones for patients in whom traditional treatments have failed.
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OBJECTIVE: The purpose of this study was to investigate the feasibility of using a holmium:yttrium-aluminum-garnet laser to permanently occlude the cystic duct in order to isolate the gallbladder from the biliary-enteric circulation and prevent gallstone formation. MATERIALS AND METHODS: To determine the optimal laser parameters (power and pulsing rate) for cystic duct thermocoagulation, 20 freshly excised porcine gallbladders with intact cystic ducts underwent low-energy (0.075-0.085 J/pulse) or high-energy (0.20-0.25 J/pulse) thermocoagulation. Histopathologic examination was done to determine the extent of cystic duct injury. After in vitro experiments, percutaneous transcholecystic laser thermocoagulation of the cystic duct was performed on 23 anesthetized domestic pigs (four controls). Cholangiograms immediately after laser thermocoagulation were obtained to assess cystic duct occlusion. Animals were sacrificed for histopathologic correlation immediately after laser thermocoagulation (n = 4), 72 hr later (n = 4), and 6 weeks later (n = 15). RESULTS: In the in vitro studies, all 10 cystic ducts in the high-energy group were occluded, while only four in the low-energy group were occluded. At histology, all cases in both groups showed circumferential injury to the cystic duct wall without injury to the cystic artery or vein. In the in vitro experiments, the cystic duct was successfully cannulated in 21 (91%) of 23 animals. Cholangiography after thermocoagulation showed occlusion of the cystic duct in 16 (84%) of 19 cases. Immediately after laser thermocoagulation, the cystic duct mucosa was circumferentially destroyed, whereas after 72 hr necrosis of the cystic duct wall and periductal tissues had occurred. By 6 weeks, all pigs had complete cystic duct fibrosis without injury to the common bile duct. CONCLUSION: Holmium:yttrium-aluminum-garnet laser thermocoagulation of the cystic duct can be performed easily, results in immediate cystic duct occlusion, and leads to permanent fibrous ductal obliteration by 6 weeks.
OBJECTIVE: Chemical gallbladder sclerosis has been attempted as a way to defunctionalize the gallbladder in patients who have undergone nonsurgical removal of gallstones and who are unable to undergo surgical/laparoscopic cholecystectomy. The purpose of this investigation was threefold: to study an animal model for chemical sclerosis of the gallbladder with 95% ethanol and 3% sodium tetradecyl sulfate, to attempt chemical sclerosis immediately after percutaneous cystic duct obliteration by laser thermocoagulation, and to assess histopathologic changes in the gallbladder after sclerosis. MATERIALS AND METHODS: Percutaneous cholecystostomy and laser thermocoagulation of the cystic duct was performed in 13 pigs. Eight pigs underwent immediate gallbladder sclerosis with 95% ethanol and 3% sodium tetradecyl sulfate while two pigs received 95% ethanol only. The remaining three pigs served as controls. The cholecystostomy catheter was removed immediately after the procedure. All animals were sacrificed 6 weeks after laser thermocoagulation. Multiple sections through the gallbladder, which included the adjacent liver, the cystic duct, and the common bile duct, were obtained for histologic examination. RESULTS: At autopsy, the gallbladder in all 10 animals who underwent gallbladder sclerosis was reduced in size compared with controls. In all treated animals, the gallbladder mucosa was denuded; however, in nine of 10 cases reepithelialization had occurred. Complete sclerosis without reepithelialization was achieved in one pig who received both ethanol and sodium tetradecyl sulfate. In the two animals who received ethanol only, the depth of wall necrosis around the gallbladder lumen was less than in those pigs who received both ethanol and sodium tetradecyl sulfate. No pigs showed signs of hepatic necrosis or injury to the common bile duct. CONCLUSION: Cystic duct laser thermocoagulation allows immediate gallbladder sclerotherapy without injury to the common bile duct. Sclerosis with ethanol and sodium tetradecyl sulfate results in denudation of the gallbladder mucosa. However, a single therapeutic session with immediate removal of the cholecystostomy catheter was inadequate for gallbladder ablation in this model because of reepithelialization.
The ability of HEp-2 cell adherent Esch. coli of aggregative phenotype (EA-Agg EC) to cause diarrhoea and to colonize the bowel of rabbits was studied. Thirty six rabbits were challenged with one of three EA-Agg EC strains (F23A; H766C and F17A-15, 3 and 3 rabbits respectively) or a control strain (K12-15 rabbits) in reversible ileal-tie in adult rabbit diarrhoea (RITARD) model. The animals were sacrificed 72 h post challenge. Severe diarrhoea occurred in greater number of F23A challenged rabbits than the controls (P < 0.05). Mucosal cultures from proximal and distal small intestine and colon yielded about 1000 times more Esch. coli in the test than control rabbits (P < 0.001 in each case). EA-Agg EC were consistently grown from mucosa in the test rabbits who commonly showed mild to moderate villous stunting and grade + to nuclear fragmentation (karyorrhexis) in the small and large bowel epithelium. The control animals had either normal villi or very mild villous stunting. Results comparable to F23A were obtained with the other two EA-Agg EC strains tested in a smaller number of animals.
A total of 274 samples were collected--180 sputum samples, 82 bronchial secretions and 12 pleural aspirates. Main fungus was Candida albicans from sputum (45.5 percent), from bronchial secretions (14.6 percent). Rest were Aspergillus, Alternaria and Helminthosporium. All the pleural aspirates were negative for fungus.