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B J Hoffman

Publications and source records attributed to B J Hoffman.

At least 55 records · Page 3Linked to original sources
PubMed1998

Local staging of anal and distal colorectal tumors with the magnetic resonance endoscope.

BACKGROUND: We prospectively assessed the feasibility and accuracy of endoscopic magnetic resonance (EMR) scanning in the local staging of anal and colorectal cancer as compared to endosonography. METHODS: Fifteen patients with biopsy-proven anal (n = 2), rectal (n = 11), and distal colonic (n = 2) cancer underwent endosonography followed by EMR imaging. Scans were acquired using the magnetic resonance receiver coil incorporated into the tip of the non-ferromagnetic endoscope. Blinded to endosonography results, two radiologists interpreted the EMR images using the TNM system. Staging results were compared to endosonography in all patients and to histopathology in the 13 colorectal cases. RESULTS: EMR imaging, well tolerated in all patients, correlated with endosonography in 10 of 15 and 12 of 15 cases for T- and N-staging, respectively. In the 13 colorectal patients with available histopathology, accuracy of EMR and of endosonography in T-staging was 77% and 85%, respectively; N-staging accuracy was 62% for both. CONCLUSIONS: For anal and distal colorectal neoplasms, EMR imaging is feasible and provides local staging comparable to endosonography.

Adenocarcinoma↗
PubMed1998

Serotonin transporter messenger RNA in the developing rat brain: early expression in serotonergic neurons and transient expression in non-serotonergic neurons.

Serotonin has been shown to affect the development of the mammalian nervous system. The serotonin transporter is a major factor in regulating extracellular serotonin levels. Using in situ hybridization histochemistry the rat serotonin transporter messenger RNA was localized during embryogenesis, the first four weeks postnatally and adulthood. Three general classes of serotonin transporter messenger RNA expression patterns were observed: (i) early detection with continued expression through adult age, (ii) transient expression colocalized with vesicular monoamine transporter 2 messenger RNA but with no detectable tryptophan hydroxylase immunoreactivity, and (iii) transient expression in the apparent absence of both vesicular monoamine transporter 2 messenger RNA and tryptophan hydroxylase immunoreactivity. For example, hybridization for serotonin transporter messenger RNA was strong in serotonin cell body-containing areas beginning early in gestation, and remained intense through adulthood. Immunoreactivity for tryptophan hydroxylase, the rate-limiting enzyme in serotonin synthesis, was completely overlapping with the presence of serotonin transporter messenger RNA in raphe nuclei postnatally. Sensory relay systems including the ventrobasal nucleus (somatosensory), lateral and medial geniculate nuclei (visual and auditory, respectively) as well as trigeminal, cochlear and solitary nuclei were representative of the second class of observations. In general, the limbic system expressed serotonin transporter messenger RNA in the third pattern with various limbic structures differing in the timing of expression. Septum, olfactory areas and the developing hippocampus contained serotonin transporter messenger RNA early in the developing brain. Other regions such as cingulate and frontopolar cortex exhibited hybridization peri- and postnatally, respectively. Several hypothalamic nuclei and pituitary transiently expressed serotonin transporter messenger RNA either postnatally or perinatally, respectively. If the observed patterns correlate with functional protein expression, distinct classes of serotonin transporter messenger RNA expression may reflect different functional roles for the serotonin transporter and serotonin, itself. Since the serotonin transporter is a target for a number of addictive substances including cocaine and amphetamine derivatives as well as antidepressants, transient expression of the serotonin transporter might suggest a window of vulnerability of associated cells to fetal drug exposure. Re-uptake, storage and re-release from non-serotonergic neurons might serve as a feedback mechanism from target neurons to serotonergic neurons. Alternatively, the transient expression of serotonin transporter messenger RNA may reflect critical periods important for tight regulation of extracellular serotonin in several brain regions, and may indicate previously unappreciated roles for serotonin as a developmental cue.

Aging↗
PubMed1998

A swine model for teaching endoscopic ultrasound (EUS) imaging and intervention under EUS guidance.

BACKGROUND AND STUDY AIMS: Endoscopic ultrasonography (EUS) has evolved into a clinically useful imaging modality. Widespread application of EUS has been hampered by the long learning curve and the paucity of training programs. We report here our efforts to develop an animal model for teaching endoscopic ultrasound. MATERIALS AND METHODS: The protocol for performing endoscopic ultrasound in live pigs included general anesthesia, endotracheal intubation, and mechanical ventilatory support. An echo-endoscope was then inserted into the pig gastrointestinal tract, and attempts were made to obtain ultrasound images that were comparable to human endoscopic ultrasound images. Intervention under EUS guidance was then attempted in the swine. RESULTS: It was possible to image the esophageal and gastric wall, pancreas, aorta, celiac artery, superior mesenteric artery, liver, and portal vein. The images obtained were analogous to human endoscopic ultrasound images. EUS-guided interventional techniques were also carried out, including EUS-guided fine-needle aspiration and celiac plexus neurolysis. CONCLUSIONS: A swine model appears to be useful for hands-on teaching in endoscopic ultrasound imaging and intervention under endoscopic ultrasound guidance.

Animals↗
PubMed1998

Local staging of esophageal cancer using endoscopic magnetic resonance imaging: prospective comparison with endoscopic ultrasound.

BACKGROUND AND STUDY AIMS: The magnetic resonance endoscope consists of a non-ferrous endoscope with a radiofrequency receiver coil incorporated into its tip. The aim of this study was to assess the accuracy of endoscopic magnetic resonance imaging for the local staging of esophageal cancer. PATIENTS AND METHODS: Prospectively, 15 patients with biopsy-proven cancer of the esophagus (n = 9) or gastroesophageal junction (n = 6) underwent endosonography followed by imaging by the magnetic resonance endoscope. The results of endoscopic magnetic resonance imaging were assessed blindly, then compared with those of endosonography, which served as the gold standard. RESULTS: Endoscopic magnetic resonance imaging of transmural tumor invasion agreed with ultrasonography in 11/15 cases and of nodal state in 12/15 cases. Endoscopic magnetic resonance images were inadequate in four cases as a result of motion artifacts. CONCLUSIONS: Endoscopic magnetic resonance imaging of esophageal cancer diagnoses local staging that is comparable to endosonography. In future, the combination of endoscopic and conventional magnetic resonance scanning may provide comprehensive staging of esophageal cancer.

Adenocarcinoma↗
PubMed1998

Endoscopic sphincterotomy for stones by experts is safe, even in younger patients with normal ducts.

OBJECTIVE: To provide current information on the risks of endoscopic sphincterotomy for stone. SUMMARY BACKGROUND DATA: In recent years (since the popularity of laparoscopic cholecystectomy), endoscopic sphincterotomy has been used increasingly for the management of bile duct stones in relatively young and healthy patients. The validity of this trend has been questioned using data on short-term complications derived from earlier decades that involved more elderly and high-risk patients. METHODS: Seven academic centers collected data prospectively using a common database. Complications within 30 days of the procedures were documented by standard criteria. RESULTS: Of 1921 patients, 112 (5.8%) developed complications; two thirds of these events were graded as mild (<3 days in hospital). There was no evidence of increased risk in younger patients or in those with smaller bile ducts. There was only one severe complication and there were no fatalities in 238 patients age <60, with bile duct diameters of <9 mm. CONCLUSION: Sphincterotomy for stones can be performed very safely by experienced endoscopists.

Age Factors↗
PubMed1998

Substance P receptor expression in intestinal epithelium in clostridium difficile toxin A enteritis in rats.

We previously reported that the inflammatory effects of Clostridium difficile toxin A on rat intestine can be significantly inhibited with a specific neurokinin-1 receptor (NK-1R) antagonist. In this study we investigated the localization and expression of NK-1R mRNA and protein in rat intestine by in situ hybridization, Northern blot analysis, and immunohistochemistry, respectively, after exposure to toxin A. Northern blot analysis showed increased mucosal levels of NK-1R mRNA starting 30 min after toxin A administration. In situ hybridization showed that toxin A increased NK-1R mRNA expression in intestinal epithelial cells after 30, 120, and 180 min. In rats pretreated with the NK-1R antagonist CP-96345 the increase in NK-1R mRNA levels after exposure to toxin A was inhibited, indicating that NK-1R upregulation is substance P (SP) dependent. One hour after exposure to toxin A many of the intestinal epithelial cells showed staining for NK-1R compared with controls. Specific 125I-SP binding to purified epithelial cell membranes obtained from ileum exposed to toxin A for 15 min was increased twofold over control and persisted for 4 h. This report provides evidence that NK-1R expression is increased in the intestinal epithelium shortly after exposure to toxin A and may be important in toxin A-induced inflammation.

Animals↗
PubMed1998

Dopamine produced by the stomach may act as a paracrine/autocrine hormone in the rat.

Dopamine (DA) has been suggested to be a protective factor in the gastrointestinal tract but neither a source of DA nor its exact targets of action have been identified. In this study, we demonstrate high levels of DA (and DOPA) which persist after chemical sympathectomy in the gastric juice of rats. Immunostaining and in situ hybridization histochemistry reveal the presence of tyrosine hydroxylase (TH), DA transporter and vesicular monamine transporters in the acid-producing parietal cells. Like DA, TH enzyme activity remains after chemical sympathectomy. We also demonstrate active reuptake and storage of DA that indicates a regulated release of this neurohormone from parietal cells. DA D1b receptor mRNA is the most abundant DA receptor subtype in gastric and duodenal epithelium. Therefore, we suggest that selective DA D1b receptor agonists may be useful adjuncts in the treatment of duodenal and gastric ulcers. Gastric epithelia possess the hallmarks of functional DA neuroendocrine cells, suggesting that DA has an important role in self-protective mechanisms of the gastrointestinal tract. These findings should allow elucidation of DA role in normal and disease states in the stomach and duodenum.

Animals↗
PubMed1998

Gastrin-producing endocrine cells: a novel source of histamine in the rat stomach.

Gastrin and histamine both potently stimulate secretion of acid into the gastric lumen. How these agents interact and how their release is controlled is poorly understood. Therefore, we decided to look for histamine in the antral portion of the rat stomach where the gastrin-producing G cells are located. We used immunocytochemical methods to visualize histamine, histidine decarboxylase (HDC, the enzyme that converts histidine to histamine), and the type 1 vesicular monoamine transporter (VMAT1, the protein responsible for moving histamine into vesicles for storage and release). We were surprised to find that histamine, HDC, and VMAT1 were all present in G cells. Our results suggest that G cells synthesize and secrete gastrin and histamine. Whether histamine acts in concert with gastrin to stimulate acid secretion, or functions as an autocrine inhibitor of gastrin release remains to be seen.

Animals↗
PubMed1997

[Initial experiences with magnetic resonance endoscopy].

BACKGROUND: In contrast to endorectal surface coils used to assess pelvic tumors, the magnetic resonance endoscope (MR) has all the features of a standard endoscope. In ex-vivo imaging of the porcine gastrointestinal tract, endoscopic MR demonstrates distinct histological layers of the gastrointestinal wall. The aim of this study was to assess the feasibility and the accuracy of endoscopic MR in local staging of patients with esophageal and rectal cancer. METHODS: From April to August 1996, 12 patients (5 female and 7 male, mean age 63 [range 44-84] years) with histologically proven esophageal (n = 6) and rectal (n = 6) cancer prospectively underwent endoscopic ultrasound (EUS) followed by endoscopic MR. The two radiologists reviewing the endoscopic MR images were blinded to the EUS results. Assessment of T and N stages was compared to EUS and histology. RESULTS: Endoscopic MR was well tolerated in all patients and there were no complications. Image quality was sufficient in 75%. Endoscopic MR T-staging correlated with EUS and histology in 7/12 and 5/7 patients respectively. Discordance was due to overstaging by endoscopic MR. N-staging correlated with EUS and histology in 10/12 and 6/8 cases respectively. Non-correlation was due to a number of false negative results at endoscopic MR. CONCLUSION: These early results demonstrate endoscopic MR to be feasible and to produce comparable local staging to EUS in patients with esophageal and rectal cancer. The ultimate goal will be to combine endoscopic MR with body coil MR imaging (for the assessment of distant metastases) in order to provide "one-step staging" for the entire evaluation of gastrointestinal tumors.

Adult↗
PubMed1997

Differentiation of benign from malignant pancreatic masses by endoscopic ultrasound.

BACKGROUND: It is often difficult to determine whether a mass in the pancreas is benign or malignant. The goal was to evaluate whether endoscopic ultrasound (EUS) can reliably establish whether a mass is benign or malignant. METHODS: One hundred five patients with possible pancreatic tumors were referred for EUS. Those who were found to have a lesion suspicious for carcinoma and did not have a known malignancy also underwent EUS-guided FNA. RESULTS: A mass suspicious for cancer was identified in 73 patients, whereas inflammatory changes or a normal pancreas was noted in 32 patients. Four of the latter 32 patients were subsequently found to have cancer. EUS-guided FNA was performed on 47 of the 73 patients with a suspicious mass and was read as cancer in 27 patients, atypia in 10 patients, and benign in 10 patients. All 10 patients with atypia were subsequently confirmed to have cancer, and 6 of the 10 patients with a benign FNA were proved to have a tumor at surgery. EUS could differentiate the lesion as malignant with a sensitivity of 95%, specificity 88%, positive predictive value 95%, and negative predictive value 88%. CONCLUSIONS: Radial array EUS is helpful in supporting or refuting a diagnosis of cancer in a patient with a pancreatic mass. Although EUS-guided FNA can confirm the diagnosis, a negative FNA should not preclude exploration when clinically indicated.

Adenocarcinoma↗
PubMed1997

A comparison of the accuracy of echo features during endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration for diagnosis of malignant lymph node invasion.

BACKGROUND: The purpose of this study was to re-evaluate echo features of lymph nodes during endoscopic ultrasound and assess the utility of these echo features and endoscopic ultrasound-guided fine-needle aspiration in predicting malignant lymph node invasion. METHODS: Thirty-five lymph nodes in 25 patients with lung, esophageal, and pancreatic cancer were evaluated by endoscopic ultrasound. Endoscopic ultrasound examinations were performed with a radial scanning echoendoscope. Confirmation of benign lymph nodes was obtained by surgical resection while malignant lymph nodes were confirmed by real-time endoscopic ultrasound-guided fine-needle aspiration with a linear array echoendoscope. RESULTS: Nineteen benign lymph nodes and 16 malignant lymph nodes in the mediastinum, celiac axis, and the peripancreatic area were included in the study. The following echo features were compared between benign and malignant lymph nodes: size greater than 1 cm, hypoechoic, distinct margins, and round shape. No single feature independently predicted malignant invasion. When all four of the above features were present in the same lymph node, the accuracy for predicting malignant invasion was 80%. However, all four features of malignant involvement were present in only 25% (4 of 16) of malignant lymph nodes. Our study also suggests that the above echo features may be a less reliable predictor of malignant invasion in pulmonary malignancies when compared to gastrointestinal cancers. Endoscopic ultrasound-guided fine-needle aspiration of lymph nodes in 22 patients revealed malignant lymph node invasion in 16 and benign cells in 6 patients. CONCLUSION: Endoscopic ultrasound-guided fine-needle aspiration is an important adjunct for accurate lymph node assessment for malignancy.

Biopsy, Needle↗
PubMed1997

Transpapillary stenting of proximal biliary strictures: does biliary sphincterotomy reduce the risk of postprocedure pancreatitis?

BACKGROUND: Pancreatitis after biliary stenting is a rare complication. To reduce this risk, some endoscopists routinely perform biliary sphincterotomy before stenting, but the value of this practice is not established. METHODS: The incidence of pancreatitis was reviewed in patients undergoing biliary stenting with and without a biliary sphincterotomy. RESULTS: Postprocedure pancreatitis occurred in 4 of 83 (4.8%) patients treated with transpapillary biliary stents. Patients with proximal biliary strictures were at significantly increased risk for postprocedure pancreatitis (4 of 24) versus those with distal or no strictures (0 of 59) (p = 0.006). The four patients with pancreatitis after stenting had not undergone sphincterotomy. Of those treated conservatively, two cases were graded severe (one fatal), and one was mild. The other patient was markedly symptomatic from pancreatitis, but improved dramatically after treatment with a needle-knife sphincterotomy done within 24 hours of the original ERCP. CONCLUSION: The risk of pancreatitis following transpapillary biliary stenting is increased in patients with proximal biliary strictures. Such lesions (malignant or benign) may serve as a fulcrum, leading to medial deflection of the stent and compression of the pancreatic orifice. The hypothesis that sphincterotomy may decrease the risk of biliary stent-induced obstructive pancreatitis should be tested in patients with proximal biliary strictures.

Adult↗
PubMed1997

Contrast-enhanced endoscopic ultrasonography with galactose microparticles: SHU508 A (Levovist).

BACKGROUND AND STUDY AIMS: To evaluate the utility of a suspension of galactose microparticles available as SHU508 A (Levovist) as a contrast agent during endoscopic ultrasonography (EUS). MATERIALS AND METHODS: Three sets of experiments were performed on three 20-25 kg swine (Sus scrofa) under general anesthesia. Upper EUS was performed with an echo endoscope with color Doppler capability (Pentax FG-32 UA). The celiac artery, superior mesenteric artery, aorta, portal vein, pancreas, and gastrointestinal wall were imaged by EUS. Multiple intravenous bolus injections of 400 mg/ml of SHU508 A were made, and their effect on color Doppler and gray-scale imaging during EUS was studied. RESULTS: After contrast injection there was a significant, visually noticeable enhancement of the color Doppler signals from the celiac artery, superior mesenteric artery, and portal vein. Vessels with weak to no color Doppler signals before injection of SHU508 A--for example, the celiac artery and superior mesenteric artery--were observed to have strong color signals after injection. The effect of SHU508 A on color Doppler imaging was easily appreciated subjectively without the need for complex quantitative measurements. No visually noticeable color Doppler enhancement was seen in vessels such as the aorta that had a very pronounced color Doppler signal even prior to the injection of contrast. Movement of particulate matter was seen in the portal vein on the gray scale. CONCLUSION: Intravenous SHU508 A as a contrast agent significantly enhances color Doppler signals during EUS. Vascualar contrast of this sort could potentially have a significant role in improving the accuracy of EUS in diagnosing malignant vascular invasion, the detection of occult pancreatic neoplasms, and the diagnosis of vascular thrombosis.

Animals↗