Correlation and accuracy of contrast-enhanced computed tomography in assessing depth of invasion of oral tongue carcinoma.

The aim of this study was to evaluate the correlation and accuracy of depth of invasion (DOI) measurement from preoperative contrast-enhanced computed tomography (CECT) scans in comparison to histopathological examination (HPE) in oral tongue squamous cell carcinoma (OTSCC). Preoperative CT scans of 18 OTSCC patients were reviewed retrospectively by a single observer to measure the DOI on axial and coronal sections; these were then compared to the HPE report. Mean DOI was compared between CECT and HPE using repeated measures ANOVA. The strength of correlation of CT-derived tumour depth was determined using the intra-class correlation coefficient (ICC) followed by assessment of accuracy by Bland-Altman plot. In general, the measurement of DOI was smaller on CECT, with a mean difference of 0.743mm on axial CT and 1.106mm on coronal CT. Regarding the correlation between CECT and HPE tumour depths, ICC was 0.956 for axial CT and 0.965 for coronal CT. Bland-Altman analysis showed that DOI from CECT and histopathological depth were in agreement with each other. In conclusion, there was excellent correlation and accurate measurement of DOI from CECT.

COVID-19: Four Paediatric Cases in Malaysia.

OBJECTIVE: This is a brief report of 4 paediatric cases of COVID-19 infection in Malaysia BACKGROUND: COVID-19, a coronavirus, first detected in Wuhan, China has now spread rapidly to over 60 countries and territories around the world, infecting more than 85000 individuals. As the case count amongst children is low, there is need to report COVID-19 in children to better understand the virus and the disease. CASES: In Malaysia, until end of February 2020, there were four COVID-19 paediatric cases with ages ranging from 20 months to 11 years. All four cases were likely to have contracted the virus in China. The children had no symptoms or mild flu-like illness. The cases were managed symptomatically. None required antiviral therapy. DISCUSSION: There were 2 major issues regarding the care of infected children. Firstly, the quarantine of an infected child with a parent who tested negative was an ethical dilemma. Secondly, oropharyngeal and nasal swabs in children were at risk of false negative results. These issues have implications for infection control. Consequently, there is a need for clearer guidelines for child quarantine and testing methods in the management of COVID-19 in children.

KRAS and BRAF mutation analysis can be reliably performed on aspirated cytological specimens of metastatic colorectal carcinoma.

BACKGROUND: Sanger sequencing is one of several reliable methods in use to detect KRAS and BRAF mutations to facilitate clinical patient selection for anti-epidermal growth factor receptor (EGFR) monoclonal antibody therapy in unresectable metastatic colorectal adenocarcinoma (CRC). Most analyses are made on pretreatment biopsy or resection specimens. There is a scarcity of published studies on the suitability of cytological samples for KRAS testing in this setting. METHODS: DNA extraction was attempted on 11 search-retrieved paired cases of histological resections or excisions of CRC and their corresponding cytological samples (representing metastases) and tested for KRAS mutations in exon 2 and 3, as well as BRAF exon 15 mutations by Sanger sequencing. Only KRAS wild-type cases were subjected to BRAF analysis because this is the setting with true diagnostic value, as these mutations are mutually exclusive. RESULTS: Of the 11 paired cases analysed, only eight histology cases showed satisfactory DNA quality for sequencing. Thus, only eight of the corresponding cytology cases were analysed. Seven of the eight cases tested showed the same KRAS genotype on both the aspirated cytology specimen of metastatic carcinoma and the primary tumour (histological specimen), from which we derive an overall concordance rate of 87.5%. The single discordant case was likely to be a true difference as it was demonstrated again on repeat testing of both samples. No BRAF mutations were detected on the four KRAS wild-type cases. CONCLUSION: A range of cytological samples are suitable for KRAS and BRAF mutation testing, be it from previously stained preparations or cell blocks. These samples would be highly valuable in cases where cytological samples are the only material available for mutation testing.

Comparative validation of c-kit exon 11 mutation analysis on cytology samples and corresponding surgical resections of gastrointestinal stromal tumours.

OBJECTIVE: Studies have shown that c-kit mutation analysis of gastrointestinal stromal tumours (GISTs) obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) can be routinely performed. We validated c-kit exon 11 mutational analysis on cell block material obtained from fine needle aspiration cytology (FNAC) for diagnostic purposes and compared it with the same analysis in formalin-fixed paraffin-embedded full sections of the corresponding resection specimens. METHODS: c-kit mutation analysis was done on cell block material obtained from ten cases encountered in our department from 1999 to 2008 on which FNAC was attempted pre-operatively. The findings were compared with analysis on full paraffin section of the corresponding resected tumours in seven cases where patients opted for resection. c-kit exon 11 was examined via bidirectional nucleic acid sequencing. RESULTS: Our results showed 100% concordance for the presence and type of exon 11 mutation in the resected and aspirated tumours in all seven cases. These mutations had diagnostic value when compared with other neoplasms that are part of the cytomorphological differential diagnosis, such as leiomyosarcoma or gastric adenocarcinomas. CONCLUSION: Molecular cytopathology is a powerful tool that can complement morphology and immunohistochemical assessment of cytological material in routine practice for the diagnosis and prognostication of GISTs. We briefly discuss the advantages and limitations of the fine needle method of obtaining tissue for the diagnosis and prognostication of GISTs, and its current therapeutic strategies.

Postpneumonectomy empyema. CT findings in six patients.

Chest radiographs and CT scans, obtained in six patients with proven postpneumonectomy empyema, were retrospectively reviewed by comparing the radiologic image obtained at present with that obtained before symptom onset. Convexity or straightening of the concave mediastinal margin of the postpneumonectomy space was identified on CT scans in all of six patients (100%), while contralateral mediastinal shift was noted on both radiographs and CT scans in four patients (67%). Multiple air-fluid levels appeared equally on radiographs and CT scans in three patients (50%). CT depicted increased thickening of the parietal pleura (n=5, 83%) and the extrapleural tissues (n=3, 50%) and empyema necessitans (n=2, 33%), which were not apparent on radiographs. Postpneumonectomy empyema is characterized on CT scans by reversal of the normal concavity of the mediastinal margin with increased thickening of the residual parietal pleura. CT is superior to radiography in assessing the manifestations of postpneumonectomy empyema.

Impairment of pressure-natriuresis and renal autoregulation in ANG II-infused hypertensive rats.

Chronic infusions of initially subpressor doses of angiotensin II (ANG II) lead to progressive hypertension over a 2-wk period and to augmented intrarenal ANG II levels. The present study was performed to investigate total renal blood flow (RBF) and medullary blood flow (MBF) autoregulatory behavior and pressure-natriuresis in ANG II-infused hypertensive rats and how these are modified by concomitant treatment with an ANG II AT(1) receptor antagonist. ANG II-infused rats (n = 27) were prepared by administration of ANG II at 60 ng/min via osmotic minipump for 13 days. Twelve of the ANG II-infused hypertensive rats were treated with losartan in the drinking water (30 mg. kg.(-1) day(-1)). Rats were anesthetized with pentobarbital sodium (50 mg/kg, ip) and prepared for renal function measurements. An aortic clamp was placed above the junction of the left renal artery to reduce renal arterial pressure. Autoregulatory responses for renal plasma flow, overall RBF, and glomerular filtration rate were impaired in ANG II-infused hypertensive rats; however, MBF autoregulation was not disrupted. Most strikingly, pressure-natriuresis was markedly suppressed in ANG II-infused hypertensive rats. Chronic treatment with losartan prevented the impairment of the pressure-natriuresis relationship caused by chronic ANG II infusion. These findings demonstrate that chronic ANG II infusion leads to marked impairment of sodium excretion and suppression of the pressure-natriuresis relationship, which may contribute to the progressive hypertension that occurs in this model. These renal effects are prevented by simultaneous treatment with an AT(1) receptor blocker.

Sonographic findings of the neopharynx after total laryngectomy: comparison with CT.

BACKGROUND AND PURPOSE: To our knowledge, sonographic findings in the neopharynx have not been well characterized. We describe our results and assess the role of sonography versus CT in patients who have undergone total laryngectomy. METHODS: We examined 25 patients (24 men and one woman; 44-78 years old) who had had a total laryngectomy. Sonography (with a 10-MHz transducer) and contrast-enhanced CT were performed in all patients. We evaluated the normal shape of the neopharynx and assessed the accuracy of sonography versus CT in detecting tumor recurrence in the neck. RESULTS: The neopharynx appears as a round or ovoid structure on imaging studies. On sonograms, the neopharyngeal wall has five layers of alternating echogenicity: an innermost hyperechoic layer of superficial mucosa, an inner hypoechoic layer of deep mucosa, a middle hyperechoic layer of submucosa, an outer hypoechoic layer of muscle, and an outermost hyperechoic layer of adventitia. On CT scans, the neopharynx appears as a three-layered structure, with an inner hyperdense layer of mucosa, a middle hypodense layer of submucosa, and an outer isodense layer of pharyngeal constrictor muscles. Nine pathologically proved recurrences were found: three local recurrences, one local recurrence with lymph node metastasis, and five cases of lymph node metastasis only. One instance of false-negative lymph node metastasis was seen at sonography and one case of false-positive local recurrence was seen at CT. CONCLUSION: The neopharynx has a unique sonographic appearance, and this imaging technique is useful for detecting local tumor recurrence in the neopharynx in patients who have had a total laryngectomy.

Nitric oxide-angiotensin II interactions in angiotensin II-dependent hypertension.

Many studies indicate that renal haemodynamic function in angiotensin II- (ANG II) dependent hypertension is not reduced as much as would be predicted from the elevated ANG II levels suggesting that counteracting renoprotective mechanisms are activated. One important renoprotective effect is mediated by increased levels of nitric oxide. Recent studies using the ANG II-infused hypertensive rat model have shown that inhibition of nitric oxide synthesis (NOS) causes greater decreases in renal blood flow and glomerular filtration rate in ANG II-infused hypertensive rats than in control rats. This augmented nitric oxide-dependent influence is localized primarily in the cortex and to the preglomerular vasculature. The differential effects on the renal cortex and medulla are also reflected by the differences in NOS activities and protein expression. Ca2+-dependent NOS activity was significantly greater in the cortex but not the medulla of the ANG II-infused hypertensive rats compared with control rats. This was associated with marked activation of endothelial NOS protein levels and smaller increases in neuronal NOS protein levels in the cortex but not in the medulla. In contrast, the Ca2+-independent NOS activity and the inducible NOS protein levels in the cortex were significantly lower in the ANG II-infused hypertensive rats. These data support the hypothesis that cortical Ca2+-dependent NOS, primarily endothelial NOS, is stimulated during the early phases of ANG II-induced hypertension and exerts a renoprotective effect on cortical haemodynamics.

Diagnosis of recurrent uterine cervical cancer: computed tomography versus positron emission tomography.

OBJECTIVE: To determine the accuracy of CT and positron emission tomography (PET) in the diagnosis of recurrent uterine cervical cancer. MATERIALS AND METHODS: Imaging findings of CT and PET in 36 patients (mean age, 53 years) in whom recurrent uterine cervical cancer was suspected were analyzed retrospectively. Between October 1997 and May 1998, they had undergone surgery and/or radiation therapy. Tumor recurrence was confirmed by pathologic examination or follow-up studies. RESULTS: In detecting recurrent uterine cervical cancer, the sensitivity, specificity, and accuracy of CT were 77.8%, 83.3%, and 80.5%, respectively, while for PET, the corresponding figures were 100%, 94.4%, and 97.2%. The Chi-square test revealed no significant difference in specificity (p =.2888), but significant differences in sensitivity (p =.0339) and accuracy (p =.0244). CONCLUSION: PET proved to be a reliable screening method for detecting recurrent uterine cervical cancer, but to determine the anatomical localization of recurrent tumors, and thus decide an adequate treatment plan, CT was eventually needed.

Increased activity and expression of Ca(2+)-dependent NOS in renal cortex of ANG II-infused hypertensive rats.

We have previously demonstrated that nitric oxide (NO) exerts a greater modulatory influence on renal cortical blood flow in ANG II-infused hypertensive rats compared with normotensive rats. In the present study, we determined nitric oxide synthase (NOS) activities and protein levels in the renal cortex and medulla of normotensive and ANG II-infused hypertensive rats. Enzyme activity was determined by measuring the rate of formation of L-[(14)C]citrulline from L-[(14)C]arginine. Western blot analysis was performed to determine the regional expression of endothelial (eNOS), neuronal (nNOS), and inducible (iNOS) isoforms in the renal cortex and medulla of control and ANG II-infused rats. Male Sprague-Dawley rats were prepared by the infusion of ANG II at a rate of 65 ng/min via osmotic minipumps implanted subcutaneously for 13 days and compared with sham-operated rats. Systolic arterial pressures were 127 +/- 2 and 182 +/- 3 mmHg in control (n = 13) and ANG II-infused rats (n = 13), respectively. The Ca(2+)-dependent NOS activity, expressed as picomoles of citrulline formed per minute per gram wet weight, was higher in the renal cortex of ANG II-infused rats (91 +/- 11) than in control rats (42 +/- 12). Likewise, both eNOS and nNOS were markedly elevated in the renal cortex of the ANG II-treated rats. In both groups of rats, Ca(2+)-dependent NOS activity was higher in the renal medulla than in the cortex; however, no differences in medullary NOS activity were observed between the groups. Also, no differences in medullary eNOS levels were observed between the groups; however, medullary nNOS was decreased by 45% in the ANG II-infused rats. For the Ca(2+)-independent NOS activities, the renal cortex exhibited a greater activity in the control rats (174 +/- 23) than in ANG II-infused rats (101 +/- 10). Similarly, cortical iNOS was greater by 47% in the control rats than in ANG II-treated rats. No differences in the activity were found for the renal medulla between the groups. There was no detectable signal for iNOS in the renal medulla for both groups. These data indicate that there is a differential distribution of NOS activity, with the Ca(2+)-dependent activity and protein expression higher in the renal cortex of ANG II-infused rats compared with control rats, and support the hypothesis that increased constitutive NOS activity exerts a protective effect in ANG II-induced hypertension to maintain adequate renal cortical blood flow.

Intrarenal nitric oxide activity and pressure natriuresis in anesthetized dogs.

Recent studies have indicated that changes in intrarenal nitric oxide (NO) production participate in mediating arterial pressure-induced changes in urinary sodium excretion. Until recently, however, the means to measure changes in intrarenal NO activity in vivo have not been available. For the present study, changes in renal tissue NO activities were assessed directly using an NO-selective microelectrode inserted into the cortical tissue of anesthetized dogs. Control studies demonstrated that the electrode was responsive to intrarenal bolus injections of acetylcholine and to the NO donor S-nitroso-acetylpenicillamine (SNAP). Intrarenal nitro-L-arginine (50 microg x kg(-1) x min(-1)) decreased renal tissue NO concentration by 593+/-127 nmol/L (P<0.05; n=7). Infusions of SNAP (1, 2, and 3 microg x kg(-1) x min(-1) for 25 minutes) in nitro-L-arginine-treated dogs (n=5) resulted in dose-dependent increases in renal tissue NO activity, which showed a positive correlation with changes in urinary excretion rates of NO metabolites, nitrates and nitrites, (r=0.62, P<0.05) and sodium (r=0.78, P<0.01). During graded reductions of renal arterial pressure within the autoregulatory range (144+/-3 to 73+/-2 mm Hg; n=10), there were decreases in tissue NO activity that were positively correlated with changes in renal arterial pressure (r=0.45; P<0.05), urinary nitrate/nitrite excretion (r=0.64, P<0.005), and urinary sodium excretion (r=0.46; P<0.05). These data support the hypothesis that acute changes in renal arterial pressure result in alterations in intrarenal NO activity, which may be responsible for the associated changes in sodium excretion.

Obliteration of the pulmonary vein in lung cancer: significance in assessing local extent with CT.

PURPOSE: The purpose of this study was to evaluate the significance of obliteration of the pulmonary vein in assessing local extent of lung cancer with CT, particularly in regard to intrapericardial extension of tumor through the vein. METHOD: Preoperative CT scans of 325 patients, who underwent thoracotomy for primary lung cancer, were reviewed. Among them, CT scans of 19 patients showed obliteration of the pulmonary vein up to its entrance into the left atrium, without filling defect in the left atrium. Surgical records of these patients were then reviewed to investigate the extent of tumor growth through the pulmonary vein, with particular emphasis on intrapericardial extension. RESULTS: The surgical records revealed extension of tumor through the pulmonary vein beyond the pericardial reflection in 14 or 19 patients. In 10 patients showing obliteration of either the left of the right superior pulmonary vein, all tumors extended beyond the pericardial reflection (100%). Intrapericardial extension occurred in four of nine patients showing obliteration of either the left or the right inferior pulmonary vein (44%). The difference was statistically significant (p < 0.05). CONCLUSION: When assessing local extent of lung cancer with CT, obliteration of the superior pulmonary vein is a highly suggestive finding for intrapericardial extension of tumor through the pulmonary vein. On the contrary, obliteration of the inferior pulmonary vein is believed to be a less reliable finding for intrapericardial extension of lung cancer.

Renoprotective effects of nitric oxide in angiotensin II-induced hypertension in the rat.

Experiments were performed in anesthetized male Sprague-Dawley rats to determine whether increased nitric oxide (NO) activity during the development of hypertension exerts a protective effect on renal cortical blood flow (CBF) and medullary blood flow (MBF). The effects of acute NO synthase inhibition on renal function and on CBF and MBF, measured by laser-Doppler flow probes, were evaluated in control and ANG II-infused hypertensive rats, prepared by the infusion of ANG II at a rate of 65 ng/min via osmotic minipumps implanted subcutaneously for 13 days. In normotensive rats (n = 8), intravenous infusion of N omega-nitro-L-arginine (NLA; 20 micrograms.100 g-1.min-1) decreased CBF by 21 +/- 4% and MBF by 49 +/- 8% and increased blood pressure from 118 +/- 1 to 140 +/- 2 mmHg. In ANG II-infused rats (n = 7), CBF and MBF decreased by 46 +/- 5% and 25 +/- 6%, respectively, during infusion of NLA. Arterial pressure increased from 160 +/- 5 to 197 +/- 7 mmHg, which was a greater absolute increase than in normotensive controls. Basal renal blood flow (RBF), estimated from p-aminohippurate clearance and hematocrit, was similar in both the control (6.0 +/- 0.5 ml.min-1.g-1) and hypertensive (6.0 +/- 0.6 ml.min-1.g-1) rats. However, NLA-induced reductions in RBF averaged 60 +/- 5% in the hypertensive rats, compared with 31 +/- 9% observed in control rats. GFR in control (0.97 +/- 0.03 ml.min-1.g-1) and hypertensive rats (0.78 +/- 0.12 ml.min-1.g-1) decreased to a similar extent during the first 30-min period of NLA infusion. GFR returned toward control levels in control rats; in contrast, GFR remained significantly decreased in the ANG II-infused rats (0.58 +/- 0.11 ml.min-1.g-1). Basal urinary sodium excretion (0.2 +/- 0.08 mueq.min-1.g-1), fractional excretion of sodium (0.3 +/- 0.13%), and urine flow (4.9 +/- 0.39 microliters.min-1.g-1) in hypertensive rats did not increase significantly after NLA treatment as occurred in normotensive controls. These data suggest that a compensatory increase in nitric oxide activity partially counteracts the vasoconstrictor influence of elevated ANG II levels to regulate renal hemodynamics and maintain cortical perfusion in the renal circulation.

Quality of mechanically deboned chicken meat frankfurter incorporated with chicken skin.

Four formulations were processed into frankfurters with different ratios of mechanically deboned chicken meat (MDCM) and cooked chicken skin (CCS) i.e. 80/0, 70/10, 60/20 and 50/30. The products were evaluated for proximate composition, cholesterol content, colour; 'L' value (lightness) and 'a' value (redness), percentage of cooking loss, physical measurements (shearforce-kgf and folding test), thiobarbituric acid value (TBA) and taste panel evaluation. The increment of CCS in the frankfurters increased the contents of moisture, ash, protein, fat, cholesterol, the lightness ('L' value) and redness ('a' value). After 3 months of frozen storage, the increment continued except for the moisture contents for formulations with 20 and 30% CCS. The lipid oxidation (TBA value) and cooking loss were lowered in formulations with CCS. After 3 months of frozen storage, TBA value decreased, while the cooking loss increased for all the formulations. The addition of CCS increased hardness of the frankfurters but affected folding ability, with formulation with 10% CCS scoring better grade. Sensory evaluation was carried out using 30 untrained panelists to evaluate aroma, colour, appearance, hardness, juiciness, chicken taste, oily taste, rancid taste and overall acceptance of the products. The addition of CCS in the frankfurters at 10 and 20% resulted in products with taste and texture that were acceptable after 3 months of frozen storage.

Device for occlusion of rectovaginal fistula: clinical trials.

PURPOSE: To evaluate a device designed for occlusion of rectovaginal fistula in patients with acquired rectovaginal fistula. MATERIALS AND METHODS: The device consisted of a disk portion, an anchoring portion, and a shaft that connected each portion. The device was framed with a nitinol wire. The disk portion was framed in a four-leaf clover configuration, and the anchoring portion had two ellipsoid arms. The disk and anchoring portions were mounted with a nylon patch and coated with silicone. The device was designed for transrectal insertion and was placed in seven women with rectovaginal fistula caused by pelvic irradiation or pelvic surgery. RESULTS: All devices were placed successfully, and all fistulas were completely occluded after placement of the device. No procedural complications were encountered. The follow-up period was 1-26 months. One patient died of distant metastasis 5 months after placement of the device. None of the patients reported leakage from the rectovaginal fistula during the follow-up period. CONCLUSION: The occlusion device may be promising and beneficial for use in occlusion of rectovaginal fistula that results from pelvic irradiation or pelvic surgery.

Metallic stents in malignant biliary obstruction: prospective long-term clinical results.

OBJECTIVE: The purpose of this prospective study was to evaluate the long-term clinical efficacy of metallic stents when used as the initial palliative treatment of patients with inoperable malignant biliary obstruction. SUBJECTS AND METHODS: From August 1991 through May 1995, 100 consecutive patients with malignant biliary obstruction were treated with percutaneous placement of metallic stents. The causes of obstruction were bile duct carcinoma (n = 50), pancreatic carcinoma (n = 17), gallbladder carcinoma (n = 6), hepatocellular carcinoma (n = 2), and metastatic lymphadenopathy in the hepatoduodenal ligament (n = 25). We used 123 stents: 64 Gianturco Z stents, 39 Hanaro spiral stents, 16 Wallstents, two tantalum Strecker stents, one Endocoil stent, and one Memotherm nitinol stent. Every 3 months we followed up all patients except those who died. The average length of follow-up was 220 days (range, 4-1125 days). Patient survival and stent patency rates were estimated by life-table analysis. RESULTS: The median length of survival for the entire patient group was 246 days: 25-week and 50-week survival rates were 62% and 25%, respectively. We found no statistically significant difference in the median length of survival between patients with hilar obstruction (256 days) and patients with common bile duct (CBD) obstruction (227 days). Patients with bile duct carcinoma had longer median survival (269 days) than did patients with other conditions (197 days). The overall median length of patency for all stents was 360 days; the 25-week and 50-week patency rates were 81% and 53%, respectively. The stent patency rate at the median length of survival was 71%. The median length of stent patency in patients with hilar obstruction (617 days) was nearly double that of patients with CBD obstruction (324 days). However, the median length of stent patency in patients with bile duct carcinoma showed no statistically significant difference from the median length in patients with other disease. Four patients (4%) died within 1 month after stent placement. Twenty-one patients (21%) developed recurrent jaundice or cholangitis. In order of frequency, the causes of recurrent jaundice were tumor overgrowth, incrustation of bile sludge, duodenal obstruction due to tumor invasion, stent impaction into the bile duct wall, stent malposition, and tumor ingrowth. CONCLUSION: Metallic stents showed a favorable patency rate with regard to patient survival. In patients with hilar obstruction, the clinical efficacy of metallic stents was superior to that in patients with CBD obstruction. We believe that placement of metallic stents is the procedure of choice for palliation of malignant biliary obstruction.

Rhabdomyosarcoma of the head and neck in adults: MR and CT findings.

PURPOSE: To evaluate imaging findings of rhabdomyosarcoma of the head and neck in adults. METHODS: We examined 11 patients (seven men and four women; 17 to 73 years old) with pathologically proved rhabdomyosarcoma of the head and neck. The tumors originated in the paranasal sinuses (n = 6), cheek (n = 3), nasal cavity (n = 1), and infratemporal fossa (n = 1). Eight of the rhabdomyosarcomas were of the embryonal type, two were pleomorphic, and one was alveolar. Necrosis was seen in four patients, but calcification or intratumoral hemorrhage was not found. Two tumors had nodal extension. Contrast-enhanced CT was performed in 10 patients, and two patients had contrast-enhanced MR imaging. RESULTS: On CT scans, the masses enhanced to the same degree as adjacent muscle. The masses showed a homogeneous pattern in six cases and a heterogeneous pattern in four cases. The tumor margins were poorly defined in eight cases. On MR images, the masses were homogeneously isointense with muscle on T1-weighted studies and were hyperintense relative to muscle on T2-weighted studies. On both CT and MR images, 10 of 11 cases showed poorly defined, homogeneous masses destroying adjacent bony structures. CONCLUSIONS: MR imaging seems to be better than CT for initial and follow-up examination of patients with rhabdomyosarcoma because of its multiplanar capability and because it more precisely defines the extent of tumor.

In vitro evaluation of polymeric matrix and porous biodegradable reservoir devices for slow-release drug delivery.

BACKGROUND AND OBJECTIVE: Biodegradable polymeric devices were evaluated in vitro for intravitreal drug delivery. MATERIALS AND METHODS: The matrix (short-term drug delivery) and the porous (longer-term drug delivery) reservoir devices were made from polycaprolactone of two molecular weights (30,000 and 56,000). Matrix devices were loaded with 5-fluorouracil or ganciclovir. Porous reservoirs were loaded with 5-fluorouracil, ganciclovir, 5-carboxyfluorescein, or foscarnet. The release was monitored in phosphate-buffered solution using ultraviolet spectrophotometry. RESULTS: Release from the matrix devices was characterized by an initial burst, followed by a nonlinear release. The porous reservoirs demonstrated zero order linear release of drugs, sustained up to 250 days in this experiment. CONCLUSIONS: The matrix device is capable of sustained release over several months; the porous reservoir can deliver drugs for over 1 year. Further studies are needed to evaluate in vivo biodegradation behavior and toxicity of drugs used for sustained release.

New self-expandable spiral metallic stent: preliminary clinical evaluation in malignant biliary obstruction.

PURPOSE: To describe a new self-expandable spiral-shaped metallic stent and to evaluate its clinical efficacy in malignant biliary obstructions. PATIENTS AND METHODS: The stent was made of a 0.01-inch (0.25-mm) stainless steel wire bent in a zigzag pattern and was formed into a spiral configuration by differing the length of legs on each bend. One revolution was composed of 10 bends, and the stent was longitudinally connected by hanging each bending point of abutting bends, without use of suture or silver solder. Twenty-six stents were placed to relieve malignant biliary obstruction in 18 patients. Follow-up of 5-11 months (mean, 7 months) was obtained. RESULTS: All stents were placed in the desired location, and no procedural complications were encountered. Within 1 week after placement, all stents regained 90% or more of their original diameters. Five patients died (range, 5-36 weeks), and 13 patients are still alive (range, 20-45 weeks). Two patients experienced recurrent jaundice and underwent further treatment. The stent was easily inserted, expanded well, was flexible, could be repositioned, and did not shorten. CONCLUSION: Favorable clinical results were obtained with this spiral stent in malignant biliary obstruction, and further clinical testing is warranted.

Obstructive jaundice in gastric carcinoma: cause, site, and relationship to the primary lesion.

OBJECTIVE: Obstructive jaundice is frequently present in patients with advanced gastric carcinoma. The purpose of this study was to assess the cause and preferential site of bile duct obstruction in patients with gastric carcinoma and to evaluate correlativity of biliary obstruction with the nature of the primary gastric lesion. METHODS: Cholangiographic findings of 54 patients with metastatic gastric carcinoma presenting with obstructive jaundice were reviewed retrospectively. The level of the bile duct obstruction was divided into four segments: segment 1, from an individual intrahepatic duct to the biliary hilum; segment 2, common hepatic duct (CHD) involvement from the biliary hilum to the level of the cystic duct; segment 3, the proximal half of the common bile duct (CBD); segment 4, the distal half of the CBD. To evaluate the characteristics of the primary gastric lesion, operative records and pathologic findings were reviewed. RESULTS: Obstruction sites were segment 1 in eight patients (15%), segment 2 in 25 (46%), segment 3 in 17 (32%), and segment 4 in four (7%). The causes of obstruction were metastatic lymphadenopathy in the hepatoduodenal ligament (50 of 54) and direct invasion of the primary or recurrent tumor (four of 54). The location of the primary gastric lesions was the antrum, antrum and body, and body in 36 (67%), 17 (31%), and 1 (2%), respectively. Borrmann type 3 lesions were present in 72% of cases, and type 2 lesions in the remaining 24%. Histologic type was undifferentiated adenocarcinoma in 91% of patients, and differentiated adenocarcinoma in the remaining. Serosal invasion was shown in 96% of the patients. CONCLUSION: Our results show that the cause of bile duct obstruction in advanced gastric carcinoma is predominantly metastatic lymphadenopathy in the hepatoduodenal ligament, and its preferential site is around the level of the cystic duct. Obstructing lesions showed characteristic cholangiographic findings.