Clinical features and outcomes of advanced HER2+ esophageal/GEJ cancer with brain metastasis

BACKGROUND

Brain metastasis (BRM) is uncommon in gastroesophageal cancer. As such, clinicopathologic and molecular determinants of BRM and impact on clinical outcome remain incompletely understood.

METHODS

We retrospectively analyzed clinicopathologic data from advanced esophageal/gastroesophageal junction (E/GEJ) patients at Johns Hopkins from 2003 to 2021. We investigated the association between several clinical and molecular features and the occurrence of BRM, with particular focus on human epidermal growth factor receptor 2 (HER2) overexpression. Survival outcomes and time to BRM onset were also evaluated.

RESULTS

We included 515 patients with advanced E/GEJ cancer. Tumors were 78.3% esophageal primary, 82.9% adenocarcinoma, 31.0% HER2 positive. Cumulative incidence of BRM in the overall cohort and within HER2+ subgroup was 13.8% and 24.3%, respectively. HER2 overexpression was associated with increased risk of BRM [odds ratio 2.45; 95% confidence interval (CI) 1.10-5.46]. On initial presentation with BRM, 50.7% had a solitary brain lesion and 11.3% were asymptomatic. HER2+ status was associated with longer median time to onset of BRM (14.0 versus 6.3 months, P < 0.01), improved median progression free survival on first-line systemic therapy (hazard ratio 0.35, 95% CI 0.16-0.80), and improved median overall survival (hazard ratio 0.20, 95% CI 0.08-0.54) in patients with BRM.

CONCLUSION

HER2 overexpression identifies a gastroesophageal cancer molecular subtype that is significantly associated with increased risk of BRM, though with later onset of BRM and improved survival likely reflecting the impact of central nervous system-penetrant HER2-directed therapy. The prevalence of asymptomatic and solitary brain lesions suggests that brain surveillance for HER2+ patients warrants prospective investigation.

Diagnostic utility of skin autofluorescence when patch test results are doubtful

BACKGROUND

The standard diagnostic test for allergic contact dermatitis is the patch test, which can also be used to identify irritant contact dermatitis. Doubtful reactions (?+) can be often clinically relevant to individuals and can require additional tests.

OBJECTIVES

The purpose of this study was to examine whether autofluorescence (AF) measurements in patients with doubtful reactions are helpful in diagnosing contact dermatitis.

METHODS

Patients with a history of contact dermatitis were patch tested on the upper back for 48-hours of occlusion using aqueous solutions of 5% sodium lauryl sulfate. Reaction intensity was scored, and AF was measured on reactive lesions and non-lesions. Three dermatologists classified the results as positive or negative using the fluorescence photographs of patients with a doubtful reaction.

RESULTS

Among doubtful reactions, the R/G% values were significantly higher in the AF- based positive group than in the negative group (P = .0086). On the other hand, the heterogeneity values of R, G, and B (HR, HG, HB) were significantly lower in the AF-based positive group (P = .0026, .0046, .0004 respectively).

CONCLUSIONS

Measuring AF along with the clinical readings can help confirm doubtful patch test reactions.

Autologous adipose tissue-derived stem cells for the treatment of complex perianal fistulas not associated with Crohn's disease: a phase II clinical trial for safety and efficacy

PURPOSE

Injection of adipose tissue-derived stem cells (ASCs) is a novel method for the treatment of complex perianal fistulas. We aimed to evaluate the safety and efficacy of ASCs in the treatment of complex anal fistulas not associated with Crohn's disease.

METHODS

A phase II clinical trial was performed comparing two different doses of ASCs (group 1: 1 × 10⁷ cells/mL and group 2: 2 × 10⁷ cells/mL). Eligible patients were administered an amount of ASCs proportional to the length of the fistula by injection into the submucosal layer surrounding the internal opening and inside of the fistula tract. ASCs at twice the initial concentration were administered if complete closure was not achieved within 8 weeks. The efficacy endpoint was the complete closure of fistulas 8 weeks after injection. Patients demonstrating complete closure at week 8 were subjected to follow-up for 6 months.

RESULTS

Fifteen patients were injected with ASCs; thirteen completed the study. Complete closure was observed in 69.2% (9/13) of patients at 8 weeks. Three of five patients in group 1, and six of eight in group 2 displayed complete closure; no significant differences were observed between the groups. Six of nine patients who showed complete closure participated in additional follow-up; five (83.3%) showed persistent response at 6 months. No grade 3 or 4 adverse events (AEs) were observed; observed AEs were not related to ASC treatment.

CONCLUSION

ASCs might be a good option for the treatment of complex perianal fistulas are not healed by conventional operative procedures.

Interlinking of hypoxia and estrogen in thyroid cancer progression

Estrogen aids in neo-vascularization of various tumors during hypoxic conditions, however the role of estrogen within the hypoxic environment of thyroid cancer is not known. In a series of experimentations, using human thyroid cancer cells, we observed that estrogen and hypoxia modulate the hypoxia inducible factor-1 (HIF-1) signaling which is abrogated by the anti-estrogen fulvestrant and the HIF-1 inhibitor YC-1 (3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole). Furthermore, we found that the conditioned medium from estrogen treated thyroid cancer cells lead to enhanced migration and tubulogenesis of human umbilical vein endothelial cells (HUVECs) which is abrogated by HIF-1 inhibitor. These findings, in addition to our previous and other scientific literature data, lead us to conclude that estrogen and hypoxia are interlinked in thyroid cancer and can equally modulate epithelial-endothelial cell interactions by mediating key cellular, metabolic and molecular processes of thyroid cancer progression. We believe that the hormonal component and cellular adaptation to oxygen tension of cancer cells are functionally equivalent with a cellular transition that can be exploited clinically for a combinational approach for thyroid cancer treatment involving antiestrogens as well as anti-hypoxic agents.

Effect of Mn and P on the macroscopic texture of Ti-Nb stabilized interstitial free steels

The effect of Mn and P on the macroscopic texture of Ti-Nb stabilized IF steels was investigated. In order to examine the evolution of microstructure and macroscopic texture during the hot-rolling, cold-rolling and annealing processes, microstructure characterization was conducted for hot-rolled, cold-rolled and annealed specimens. The initial grain size of hot-rolled specimens was a main parameter in determining the development of the macroscopic texture of the annealed specimens.

P5-08-06: Comparison of Mammographic Density between Ductal Carcinoma In Situ and Benign Breast Disease

Background: High breast density is an independent risk factor for breast cancer as well as benign breast diseases. However there are few studies about breast density of ductal carcinoma in situ (DCIS) and benign breast disease(BBD). In this study, we investigated patterns of breast density of DCIS and BBD, and comparatively analyzed breast densities of DCIS and BBD.

Material and Methods From 2008 to 2009, 345 patients underwent surgery for DCIS at Asan Medical Center, and 295 patients for BBD at 2010. We retrospectively reviewed each groups and estimated cranio-caudal view of digital mammogram of unaffected breast by computer-assisted thresholding methods, using Cumulus 4, version 4.0. For BBD we included atypical ductal hyperplasia, fibroadenoma, papilloma(atypical/intraductal), phyllodes tumor(benign/borderline), and excluded unavailable mammogram(mostly, because of scanned films from outside hospitals and previously diagnosed breast cancer).

Results Mean ages of each group were 46.51 year old in DCIS group and 41.43 year old in BBD group, and the mean percentage density(PD) were 44.89% and 45.27%, respectively.

Effects of gastrodia elata bl on phencyclidine-induced schizophrenia-like psychosis in mice

It has been demonstrated that 5-HT_1A receptors play an important role in the pathophysiology of schizophrenia. Because Gastrodia elata Bl (GE) modulates the serotonergic system, we examined whether GE could affect phencyclidine (PCP)-induced abnormal behavior in mice. Repeated treatment with PCP increased immobility time, while it decreased social interaction time and recognition memory. PCP-induced abnormal behaviors were significantly attenuated by GE, and these effects were comparable to those of 8-OH-DPAT, a 5-HT_1A receptor agonist. Furthermore, GE-mediated effects were counteracted by WAY 100635, a 5-HT_1A receptor antagonist. Our results suggest that the antipsychotic effects of GE are, at least in part, mediated via activation of 5-HT_1A in mice.

Gastrodia Elata Bl Attenuates Cocaine-Induced Conditioned Place Preference and Convulsion, but not Behavioral Sensitization in Mice: Importance of GABA(A) Receptors

It has been suggested that GABAergic neurotransmission can modulate cocaine dependence and seizure activity. Since Gastrodia elata Bl (GE), an oriental herb agent, has been shown to enhance GABAergic transmission, we examined whether GE affects cocaine-induced seizures, conditioned place preference (CPP), and behavioral sensitization in mice. Treatment with GE (500 or 1000 mg/kg, p.o.) significantly delayed seizure onset time and significantly shortened seizure duration induced by cocaine (90 mg/kg, i.p.). In addition, cocaine (15 mg/kg, i.p.)-induced CPP was significantly attenuated by GE in a dose-dependent manner. However, GE did not significantly alter behavioral sensitization induced by cocaine (15 mg/kg, i.p.). In order to understand whether GABAergic receptors are implicated in GE-mediated pharmacological action in response to cocaine, GABA_A receptor antagonist bicuculline and GABA_B receptor antagonist SCH 50911 were employed in the present study. GE-mediated attenuations on the cocaine-induced seizures and CPP were significantly reversed by bicuculline (0.25 or 0.5 mg/kg, i.p.), but not by SCH 50911 (1.5 or 3.0 mg/kg, i.p.). Therefore, our results suggest that GE attenuates cocaine-induced seizures and CPP via, at least in part, GABA_A receptor activation.

Gastrodia elata bl attenuates methamphetamine-induced dopaminergic toxicity via inhibiting oxidative burdens

It has been recognized that Gastrodia elata Bl (GE), an oriental herb medicine, ameliorates various neurological disorders, that GE modulates the monoaminergic and GABAergic systems, and that GE possess antioxidant activities. We examined whether GE affects methamphetamine (MA)-induced striatal dopaminergic toxicity in mice. Treatment with MA (7.5 mg/kg, i.p. × 4) resulted in significant decreases in behavioural activity (as shown by locomotor activity and rota rod performance), dopamine level, tyrosine hydroxylase (TH) activity, and TH protein expression (as evaluated by immunocytochemistry and western blot analysis). In addition, MA treatment showed significant increases in lipid peroxidation [as evaluated by 4-hydroxy-2-nonenal (4-HNE) expression and malondialdehyde formation], protein oxidation (as shown by protein carbonyl expression and its formation), and reactive oxygen species (ROS) formation. Treatment with GE significantly attenuates MA-induced behavioural and dopaminergic impairments, and oxidative stresses in a dose-dependent manner. Our results suggest that GE treatment shows anti-dopaminergic effects in response to MA insult via, at least in part, inhibiting oxidative stresses in the striatum of the mice.

Long-term randomized controlled trial of a novel nanopowder hemostatic agent (TC-325) for control of severe arterial upper gastrointestinal bleeding in a porcine model

BACKGROUND AND STUDY AIM

Endoscopic therapy of brisk upper gastrointestinal bleeding remains challenging. A proprietary nanopowder (TC-325) has been proven to be effective in high pressure bleeding from external wounds. The efficacy and safety of TC-325 were assessed in a survival gastrointestinal bleeding animal model.

METHOD

10 animals were randomized to treatment or sham. All animals received intravenous antibiotics, H2-blockers and heparin (activated clotting time 2 × normal). In a sterile laparotomy the gastroepiploic vessels were dissected, inserted through a 1-cm gastrotomy, and freely exposed in the gastric lumen, and the exposed vessel lacerated by needle knife. The treatment group received TC-325 by a modified delivery catheter while the sham group received no endoscopic treatment. Time to hemostasis, and mortality at 60 minutes, 24 hours, 48 hours, and 7 days were noted. Necropsy was performed in all animals.

RESULTS

Spurting arterial bleeding was achieved in all animals. No control animal showed hemostasis within the first hour compared with 100 % (5 / 5) in the treatment arm (mean 13.8 minutes, P < 0.0079). Durable hemostasis was achieved with no evidence of rebleeding after 1 and 24 hours in 80 % (4 / 5) of the treated animals compared with none in the control group ( P < 0.0098). None of the control animals survived more than 6 hours. Necropsy at 1 week in treated animals revealed healed gastrotomy without foreign body granuloma or embolization to the lung or brain.

CONCLUSION

TC-325 is safe and highly effective in achieving hemostasis in an anticoagulated severe arterial gastrointestinal bleeding animal model.

Non-destructive evaluation of nano-sized structure of thin film devices by using small angle neutron scattering

Nano-sized multi-layers copper-doped SrZrO3, platinum (Pt) and silicon oxide (SiO2) on silicon substrates were prepared by dense plasma focus (DPF) device with the high purity copper anode tip and analyzed by using small angle neutron scattering (SANS) to establish a reliable method for the non-destructive evaluation of the under-layer structure. Thin film was well formed at the time-to-dip of 5 microsec with stable plasma of DPF. Several smooth intensity peaks were periodically observed when neutron beam penetrates the thin film with multi-layers perpendicularly. The platinum layer is dominant to intensity peaks, where the copper-doped SrZnO3 layer next to the platinum layer causes peak broadening. The silicon oxide layer has less effect on the SANS spectra due to its relative thick thickness. The SANS spectra shows thicknesses of platinum and copper-doped SrZnO3 layers as 53 and 25 nm, respectively, which are well agreement with microstructure observation.

Study of the effect of nano-sized precipitates on the mechanical properties of boron-added low-carbon steels by neutron scattering techniques

The effect of nano-sized precipitates on the mechanical properties of boron-added low-carbon steels was studied by neutron scattering techniques such as powder diffraction, small-angle scattering and particle tracking autography.

Small-angle neutron scattering (SANS) and neutron powder diffraction (ND) techniques were used to study quantitatively the effect of nano-sized precipitates and boron addition on the mechanical properties of low-carbon steels. SANS was used to evaluate nano-sized precipitates, smaller than about 600 Å in diameter, and ND was used to determine the weight fraction of the cementite precipitates. Fine core–shell structured spherical precipitates with an average radius of ~50 Å, such as MnS and/or CuS, surrounded by BN layers were observed in the boron-added (BA) low-carbon steels; fine spherical precipitates with an average radius of ~48 Å were mainly observed in the boron-free (BF) low-carbon steels. In the BA steels, the number of boron precipitates, such as BN, Fe₃(C,B) and MnS, surrounded by BN layers increased drastically at higher hot-rolling temperatures. The volume fraction of the fine precipitates of the BA steels was higher than that of the BF steels; this difference is related to the rapid growth of the BN layers on the MnS and CuS precipitates. Boron addition to low-carbon steels resulted in a reduction in strength and an improvement in elongation; this behaviour is related to the reduction of the solute carbon and the nitrogen contents in the ferrite matrix caused by the precipitation of BN, as well by the increase in the volume fraction of the cementites.

Endoscopic retrograde cholangiopancreatography, but not esophagogastroduodenoscopy or colonoscopy, significantly increases portal venous pressure: direct portal pressure measurements through endoscopic ultrasound-guided cannulation

BACKGROUND AND STUDY AIMS

Changes in portal pressure during endoscopy have not been previously evaluated. The aims of this study were to assess the effect of esophagogastroduodenoscopy (EGD), colonoscopy, and endoscopic retrograde cholangiopancreatography (ERCP) on portal vein, inferior vena cava (IVC), and systemic pressures.

PATIENTS AND METHODS

Five acute experiments were performed on 50-kg pigs utilizing endoscopic ultrasound (EUS)-guided catheterization of the portal vein and IVC. Systemic, intra-abdominal, IVC, and portal vein pressures were monitored during colonoscopy, EGD, and ERCP with endoscopic sphincterotomy. After endoscopy the animals were sacrificed for necropsy. The main outcome measure was pressure change during each type of endoscopic procedure.

RESULTS

There were no significant changes in heart rate or systemic pressure during all endoscopic procedures. Intra-abdominal pressure increased during colonoscopy ( P = 0.02) and ERCP ( P = 0.007). However, mean portal venous pressure was significantly elevated only after the injection of contrast into the common bile duct, reaching its peak value at the time of biliary sphincterotomy (39.0 +/- 15.2 mm Hg vs. 13.4 +/- 3.6 mm Hg at baseline, P = 0.006). Mean peak IVC pressure was also elevated during ERCP, but it did not reach statistical significance (24.0 +/- 10.7 mm Hg vs. 12.6 +/- 4.1 mm Hg at baseline, P = 0.06).

CONCLUSION

EGD and colonoscopy did not cause significant changes in portal vein, IVC, or systemic pressures. ERCP with biliary sphincterotomy increased portal pressure with only limited effect on IVC and systemic pressures. These new data indicate a possible connection between ERCP with sphincterotomy and portal pressure, and may be clinically important for patients with liver disease and other causes of portal hypertension who undergo this procedure.

Severity of post-ERCP pancreatitis directly proportional to the invasiveness of endoscopic intervention: a pilot study in a canine model

BACKGROUND AND STUDY AIMS

Pancreatitis complicates 1% - 22% of endoscopic retrograde cholangiopancreatography procedures. The study aims were to develop a reproducible animal model of post-ERCP pancreatitis (PEP), and investigate the impact of endoscopic technique on severity of PEP.

PATIENTS AND METHODS

ERCP was carried out in six male hound dogs. Pancreatitis was induced by one of three escalating methods: 1) pancreatic acinarization with 20 - 30 mL of contrast; 2) acinarization + ductal balloon occlusion + sphincterotomy; 3) acinarization + intraductal synthetic bile injection + ductal balloon occlusion + sphincterotomy. Dogs 5 and 6 received a pancreatic stent. Necropsy was performed on postoperative day 5. All pancreatic specimens were graded by two blinded pathologists according to a validated scoring system. All dogs were compared with three control dogs.

RESULTS

Dogs 1 - 4 developed clinical pancreatitis and hyperamylasemia (11 736 vs. 722 U/L, P = 0.02). Total injury scores were significantly elevated compared with controls (6.85 vs. 1.06, P = 0.004). There was significant increase in acinar cell necrosis (0.86 vs. 0.06, P = < 0.001), and all other categories (except fibrosis) demonstrated elevated injury scores . Dogs 5 and 6 developed clinical pancreatitis without significant hyperamylasemia; total injury scores were elevated compared with controls (4.83 vs. 1.06, P = 0.01), but lower than in Dogs 1 - 4 (4.83 vs. 6.85, P = 0.25). There was escalating severity of pancreatic injury from Dogs 1 to 4 correlating with the method of endoscopic injury used.

CONCLUSION

Severity of PEP is directly proportional to invasiveness of endoscopic intervention. Pancreatic acinarization, even without balloon occlusion and sphincterotomy, can be used as a reliable animal model for future studies investigating therapy and prevention of disease.

Preliminary pneumoperitoneum facilitates transgastric access into the peritoneal cavity for natural orifice transluminal endoscopic surgery: a pilot study in a live porcine model

BACKGROUND AND STUDY AIMS

Safe entrance into the peritoneal cavity through the gastric wall is paramount for the successful clinical introduction of natural orifice transluminal endoscopic surgery (NOTES). The aim of the study was to develop alternative safe transgastric access to the peritoneal cavity.

PATIENTS AND METHODS

We performed 11 survival experiments on 50-kg pigs. In sterile conditions, the abdominal wall was punctured with a Veress needle. The peritoneal cavity was insufflated with 2 L carbon dioxide (CO (2)). A sterile endoscope was introduced into the stomach through a sterile overtube; the gastric wall was punctured with a needle-knife; after balloon dilation of the puncture site, the endoscope was advanced into the peritoneal cavity. Peritoneoscopy with biopsies from abdominal wall, liver and omentum, was performed. The endoscope was withdrawn into the stomach. The animals were kept alive for 2 weeks and repeat endoscopy was followed by necropsy.

RESULTS

The pneumoperitoneum, easily created with the Veress needle, lifted the abdominal wall and made a CO (2)-filled space between the stomach and adjacent organs, facilitating gastric wall puncture and advancement of the endoscope into the peritoneal cavity. There were no hemodynamic changes or immediate or delayed complications related to pneumoperitoneum, transgastric access, or intraperitoneal manipulations. Follow-up endoscopy and necropsy revealed no problems or complications inside the stomach or peritoneal cavity.

CONCLUSIONS

Creation of a preliminary pneumoperitoneum with a Veress needle facilitates gastric wall puncture and entrance into the peritoneal cavity without injury to adjacent organs, and can improve the safety of NOTES.

The utility of contrast-enhanced endoscopic ultrasound in monitoring ethanol-induced pancreatic tissue ablation: a pilot study in a porcine model

BACKGROUND AND STUDY AIMS

Pancreatic ablation is gaining popularity for the treatment of focal pancreatic lesions. The aim of our study was to evaluate local effects of intrapancreatic alcohol injection and the utility of contrast-enhanced endoscopic ultrasound (EUS) for its monitoring in a porcine model.

METHODS

We performed four survival experiments on 50-kg pigs. Under linear EUS guidance, 0.5 mL of 50% ethanol plus purified carbon particle solution (GI Spot) was injected into the pancreatic body to create a focal area of pancreatic necrosis. The animals survived for 24-48 hours (pigs # 1, # 2, and # 3) and 7 days (pig # 4). EUS was then repeated with and without perflutren lipid microspheres (Definity) administration through the peripheral vein. Standard and microsphere-enhanced images of the pancreas were compared. Afterwards the animals were euthanized for necropsy.

RESULTS

Alcohol injection caused focal pancreatic necrosis, which was barely seen by standard EUS as a subtle hypoechoic lesion 1 cm in diameter. Color and power Doppler EUS of this region did not reveal any blood flow. After intravenous injection of microspheres, color Doppler EUS revealed marked contrast enhancement of normal pancreatic parenchyma with a clearly delineated avascular alcohol-treated area, which on postmortem examination corresponded to the discrete necrotic area marked with carbon particles.

CONCLUSIONS

EUS-guided alcohol injection consistently causes focal areas of pancreatic necrosis. Contrast-enhanced EUS with microspheres improves visualization of altered pancreatic vascular perfusion and can be used to facilitate detection of small pancreatic lesions and its follow-up post-ablation.

Is blood the ideal submucosal cushioning agent? A comparative study in a porcine model

BACKGROUND AND STUDY AIMS

Creation of a submucosal cushion before endoscopic mucosal resection (EMR) significantly reduces perforation risk. We evaluated six solutions as cushioning agents in live pigs.

MATERIAL AND METHODS

5 ml of normal saline, normal saline plus epinephrine, albumin 12.5 %, albumin 25 %, hydroxypropyl methylcellulose, and the pig's own whole blood were endoscopically injected into the porcine esophageal submucosa. Blood was obtained from a peripheral vein immediately before injection. Injections were made every 4 cm from the gastroesophageal junction. The time from completion of the injection to disappearance of the cushion was recorded. Endoscopy was repeated at 48 hours post injection. Two EMRs were performed after blood injection. Statistical analysis employed one-way analysis of variance followed by pairwise T test comparisons using the Bonferroni correction.

RESULTS

Five animal experiments were completed. The mean time to dissipation of the submucosal cushion was shortest for saline plus epinephrine sites (2.87 minutes, SD 2.21) followed by the saline (4.8 minutes, SD 1.56), albumin 12.5 % (5.68 minutes, SD 3.48), albumin 25 % (7.83 minutes, SD 2.02), hydroxypropyl methylcellulose (9.77 minutes, SD 1.55), and blood sites (38.6 minutes, SD 6.07). Injection of blood resulted in significantly longer mucosal elevation than any other solution ( P < 0.0007). Blood from the cushion did not hamper visualization and facilitated EMR.

CONCLUSION

Blood produces the most durable cushion compared with standard agents, also having the advantages of being readily available and without cost. Albumin 25 % provides as durable a cushion as hydroxypropyl methylcellulose.

Ascorbate attenuates trimethyltin-induced oxidative burden and neuronal degeneration in the rat hippocampus by maintaining glutathione homeostasis

The specific role of endogenous glutathione in response to neuronal degeneration induced by trimethyltin (TMT) in the hippocampus was examined in rats. A single injection of TMT (8 mg/kg, i.p.) produced a rapid increase in the formation of hydroxyl radical and in the levels of malondialdehyde (MDA) and protein carbonyl. TMT-induced seizure activity significantly increased after this initial oxidative stress, and remained elevated for up to 2 weeks post-TMT. Although a significant loss of hippocampal Cornus Ammonis CA1, CA3 and CA4 neurons was observed at 3 weeks post-TMT, the elevation in the level of hydroxyl radicals, MDA, and protein carbonyl had returned to near-control levels at that time. In contrast, the ratio of reduced to oxidized glutathione remained significantly decreased at 3 weeks post-TMT, and the glutathione-like immunoreactivity of the pyramidal neurons was decreased. However glutathione-positive glia-like cells proliferated mainly in the CA1, CA3, and CA4 sectors and were intensely immunoreactive. Double labeling demonstrated the co-localization of glutathione-immunoreactive glia-like cells and reactive astrocytes, as indicated by immunostaining for glial fibrillary acidic protein. This suggests that astroglial cells were mobilized to synthesize glutathione in response to the TMT insult. The TMT-induced changes in glutathione-like immunoreactivity appear to be concurrent with changes in the expression levels of glutathione peroxidase and glutathione reductase. Ascorbate treatment significantly attenuated TMT-induced seizures, as well as the initial oxidative stress, impaired glutathione homeostasis, and neuronal degeneration in a dose-dependent manner. These results suggest that ascorbate is an effective neuroprotectant against TMT. The initial oxidative burden induced by TMT may be a causal factor in the generation of seizures, prolonged disturbance of endogenous glutathione homeostasis, and consequent neuronal degeneration.

Irradiation Time and Ablation Rate of Enamel in Contact and Non-contact Irradiation with Er:YAG Laser

OBJECTIVE

The relationship between changes in ablation rate of enamel with irradiation time was investigated to find the most effective irradiation time for tooth ablation by Er:YAG laser.

BACKGROUND DATA

Previous studies have shown that the Er:YAG laser has the ability to ablate tooth material effectively, but that the efficiency and effectiveness of ablation are determined by various parameters such as energy, pulse frequency, the amount of water, and irradiation time.

METHODS

Contact and non-contact irradiation of the Er:YAG laser were carried out respectively for 1, 3, 5, and 7 s on the enamel surface of each specimen using a combination of a 400 mJ/pulse at 20 Hz and water flow rate of 6.75 mL/min, and quantitative measurements using a mass balance were performed to compare the resulting ablation rates.

RESULTS

The ablation weight, by taking the mean of both contact and non-contact irradiation, generally increased with irradiation exposure time, but no significant increases in ablation were seen in specimens that had been exposed for > 3 s in either the contact or non-contact irradiation group. Results in the non-contact irradiation group indicated superior ablation of enamel compared to that in the contact irradiation group.

CONCLUSION

Irradiation exposure of < or = 3 s per application of laser beam is recommended to ablate enamel effectively in both non-contact and contact irradiation.

Selegiline potentiates the effects of EGb 761 in response to ischemic brain injury

We evaluated whether combined treatment with selegiline, a selective MAO-B inhibitor, and EGb 761, a standard extract of Ginkgo biloba, has synergistic effects against ischemic reperfusion injury (IRI) in gerbils. Interestingly, we observed that pretreatment with EGb 761 significantly attenuated selegiline-induced hyperactivity. This finding paralleled striatal fos-related antigen immunoreactivity (FRA-IR) in mice. Four minutes of bilateral carotid artery occlusion caused substantial cell loss in the CA1 of the hippocampus 5 days post-ischemic insult. Pretreatment with EGb 761, with or without selegiline, significantly attenuated this neuronal loss. Combined treatment with EGb 761 plus selegiline was more efficacious in preventing this loss. Synaptosomal formations of protein carbonyl, lipid peroxidation (malondialdehyde (MDA) + 4-hydroxyalkenal (4-HDA)), and reactive oxygen species (ROS) in the hippocampus remained elevated 5 days post-ischemic insult. The antioxidant effects appeared to be most significant in the group treated with EGb 761 plus selegiline. This combined treatment produced more significant attenuation of IRI-induced alterations in intramitochondrial calcium accumulation, the mitochondrial transmembrane potential, and mitochondrial Mn-superoxide dismutase-like immunoreactivity (Mn-SOD-IR) than either treatment alone. Our results suggest that co-administration of EGb 761 and selegiline produces significant neuroprotective effects via suppression of oxidative stress and mitochondrial dysfunction without affecting neurological function.

Hydrocele of the canal of Nuck in a girl: ultrasound and MR appearance

Hydrocele of the canal of Nuck is a rare condition in females. A small evagination of parietal peritoneum forms the canal of Nuck. Failure of complete obliteration of the canal results in either an indirect inguinal hernia or a hydrocele of the canal of Nuck. We present a case in a 7-year-old girl. On ultrasound, there was a comma-shaped cyst with the tail directed cranially toward the inguinal canal. The cyst had no internal echoes and demonstrated increased through transmission. Coronal and axial MR showed a thin walled cystic mass.

Immunocytochemical evidence that amyloid beta (1-42) impairs endogenous antioxidant systems in vivo

Amyloid beta, the major constituent of the senile plaques in the brains of patients with Alzheimer's disease, is cytotoxic to neurons and has a central role in the pathogenesis of the disease. We have previously demonstrated that potent antioxidants idebenone and alpha-tocopherol prevent learning and memory impairment in rats which received a continuous intracerebroventricular infusion of amyloid beta, suggesting a role for oxidative stress in amyloid beta-induced learning and memory impairment. To test the hypothesis, in the present study, we investigated alterations in the immunoreactivity of endogenous antioxidant systems such as mitochondrial Mn-superoxide dismutase, glutathione, glutathione peroxidase and glutathione-S-transferase following the continuous intracerebroventricular infusion of amyloid beta for 2 weeks. The infusion of amyloid beta (1-42) resulted in a significant reduction of the immunoreactivity of these antioxidant substances in such brain areas as the hippocampus, parietal cortex, piriform cortex, substantia nigra and thalamus although the same treatment with amyloid beta (40-1) had little effect. The alterations induced by amyloid beta (1-42) were not uniform, but rather specific for each immunoreactive substance in a brain region-dependent manner. These results demonstrate a cytological effect of oxidative stress induced by amyloid beta (1-42) infusion. Furthermore, our findings may indicate a heterogeneous susceptibility to the oxidative stress produced by amyloid beta.

Prenatal exposure to magnetic field increases dopamine levels in the striatum of offspring

1. The putative effects of prenatal exposure to magnetic field (MF) have recently received much interest. In the present study, mice were exposed to a MF of 50 mT during gestation (0-19 days). 2. After the exposure was terminated, mothers and offspring were returned to normal laboratory conditions. We then determined changes in striatal levels of dopamine (DA) and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the offspring. 3. Our results indicate that prenatal exposure to MF increases levels of DA and DOPAC in the striatum at 4, 8 and 12 weeks postnatally.

Carbetapentane attenuates kainate-induced seizures via sigma-1 receptor modulation

We examined the effects of a non-opioid antitussive, carbetapentane (CB) on kainic acid (KA)-induced neurotoxicity in rats. KA administration (10 mg/kg, i.p.) produced robust behavioral convulsions lasting 4 to 5 h. CB (12.5 and 25 mg/kg. i.p.) pretreatment consistently and in a dose-dependent manner reduced the KA-induced seizures, mortality, and marked loss of cells in regions CA1 and CA3 of the hippocampus. Consistently, CB pretreatment also significantly attenuated the KA-induced increase in Fos-related antigen immunoreactivity in the hippocampus. In contrast, pretreatment with the sigma-1 receptor antagonist BD1047 (1 and 2 mg/kg, i.p.) blocked, in a dose-related manner, the neuroprotection afforded by CB. These results suggest that CB provides neuroprotection against KA insult via sigma-1 receptor modulation.

Anticonvulsant effects of new morphinan derivatives

We synthesized a series of compounds that are modified in positions 3 and 17 of the morphinan ring system, with the intention of developing ideal anticonvulsant agents. We examined the effects of these compounds on kainic acid (KA)-induced seizures, and on locomotor patterns in rats. We found that compounds 5, 6, and 8 exhibit novel anticonvulsant effects, with negligible psychotropic effects.

Dextromethorphan affects cocaine-mediated behavioral pattern in parallel with a long-lasting Fos-related antigen-immunoreactivity

In order to understand the underlying mechanisms responsible for the behaviors mediated by dextromethorphan (DM), we examined the effects of DM on locomotor activity and locomotor patterns in mice, and Fos-related antigen immunoreactivity (FRA-IR) of mouse brain following repeated administration of cocaine. Combined treatments (30 min prior to each cocaine administration) with DM dose-dependently decreased locomotor activity for high doses of cocaine (20 mg/kg, i.p./day x 7). DM combinations did not significantly affect hyperactivity for 10 mg cocaine/kg, i.p./day x 7. In contrast, combined treatments with DM increased the locomotor activity for 5 mg cocaine/kg, i.p./day x 7. These results were consistent with alterations in marginal activity. Repeated administration with cocaine or DM increased FRA-IR in the nucleus accumbens (NAc) and striatum which lasted for at least 7 days. Our results suggest that DM exhibits biphasic effects on the locomotor stimulation induced by cocaine, and that locomotor activities are in parallel with FRA-IR of the striatal complex. However, the role of FRA-IR regulated by DM or/and cocaine remains to be further determined.

Effects of dextromethorphan on the seizures induced by kainate and the calcium channel agonist BAY k-8644: comparison with the effects of dextrorphan

BAY k-8644 (an L-type Ca(2+) channel agonist of the dihydropyridine class) is recognized as a potent convulsant agent. In this study, we used BAY k-8644 to explore the effects of dextromethorphan (DM) and its major metabolite, dextrorphan (DX), on the (pro)convulsant activity regulated by calcium channels. BAY k-8644 (2 mg/kg, s.c) potentiated seizures induced in rats by kainic acid (KA) (10 mg/kg, i.p.). DM appears more efficacious than DX in attenuation of KA-induced seizures. The anticonvulsant effect of a low dose (12.5 mg/kg, s.c.) of DM was reversed by BAY k-8644 (2 mg/kg) challenge. In contrast, BAY k-8644 (1 or 2 mg/kg) did not significantly affect an anticonvulsant effect from a higher dose (25 mg/kg) of either DM or DX. Intracerebroventricular injection of BAY k-8644 (37.5 microg) significantly induced seizures in mice. DM (12.5 or 25 mg/kg) pretreatment more significantly attenuated seizures evoked by BAY k-8644 than did DX (12.5 or 25 mg/kg). Furthermore, seizure activity induced by KA or BAY k-8644 was consistent with respective activator protein-1 DNA binding activity of the hippocampus. Therefore, our results suggest that the anticonvulsant effects of the morphinans involve, at least in part, the L-type calcium channel. They also suggest that DM is a more potent anticonvulsant than DX in the KA and BAY k-8644 seizure models.

Recruitment of the transcriptional machinery through GAL11P: structure and interactions of the GAL4 dimerization domain

The GAL4 dimerization domain (GAL4-dd) is a powerful transcriptional activator when tethered to DNA in a cell bearing a mutant of the GAL11 protein, named GAL11P. GAL11P (like GAL11) is a component of the RNA-polymerase II holoenzyme. Nuclear magnetic resonance (NMR) studies of GAL4-dd revealed an elongated dimer structure with C(2) symmetry containing three helices that mediate dimerization via coiled-coil contacts. The two loops between the three coiled coils form mobile bulges causing a variation of twist angles between the helix pairs. Chemical shift perturbation analysis mapped the GAL11P-binding site to the C-terminal helix alpha3 and the loop between alpha1 and alpha2. One GAL11P monomer binds to one GAL4-dd dimer rendering the dimer asymmetric and implying an extreme negative cooperativity mechanism. Alanine-scanning mutagenesis of GAL4-dd showed that the NMR-derived GAL11P-binding face is crucial for the novel transcriptional activating function of the GAL4-dd on GAL11P interaction. The binding of GAL4 to GAL11P, although an artificial interaction, represents a unique structural motif for an activating region capable of binding to a single target to effect gene expression.

Characterization of a MEN1 ortholog from Drosophila melanogaster

Multiple endocrine neoplasia type 1 (MEN1) is a familial cancer syndrome characterized by tumors of the parathyroid, entero-pancreatic neuroendocrine and pituitary tissues and caused by inactivating mutations in the MEN1 gene. Menin, the 610-amino acid nuclear protein encoded by MEN1, binds to the transcription factor JunD and can repress JunD-induced transcription. We report here the identification of a MEN1 ortholog in Drosophila melanogaster, Menin1, that encodes a 763 amino acid protein sharing 46% identity with human menin. Additionally, 69% of the missense mutations and in-frame deletions reported in MEN1 patients appear in amino acid residues that are identical in the Drosophila and human protein, suggesting the importance of the conserved regions. Drosophila Menin1 gene transcripts use alternative polyadenylation sites resulting in 4.3 and 5-kb messages. The 4.3-kb transcript appears to be largely maternal, while the 5-kb transcript appears mainly zygotic. The binding of Drosophila menin to human JunD or Drosophila Jun could not be demonstrated by the yeast two-hybrid analysis. The identification of the MEN1 ortholog from Drosophila melanogaster will provide an opportunity to utilize Drosophila genetics to enhance our understanding of the function of human menin.

Role of angiography in the evaluation of patients with pulsatile tinnitus

OBJECTIVES/HYPOTHESIS

Pulsatile tinnitus in the face of normal findings on otoscopy is a common otological diagnostic dilemma and can be due to serious vascular malformations such as transverse or sigmoid sinus dural arteriovenous fistula (transverse or sigmoid sinus [TS] DAVF). Left untreated, TS DAVF may result in significant morbidity and mortality. TS DAVF can be suspected or diagnosed with computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA), with the gold standard being angiography. Our objective was to assess the utility of these various diagnostic modalities in the diagnosis of dural arteriovenous fistula.

STUDY DESIGN

Retrospective clinical review.

METHODS

Between 1986 and 1996, 54 patients were evaluated and treated for TS DAVF. Between 1996 and 1999, an additional 33 patients underwent MRI combined with MRA for the evaluation of pulsatile tinnitus. A retrospective review of the medical records for both groups, with special attention to clinical presentation, diagnostic evaluation, therapy, and outcome, was performed.

RESULTS

All patients had pulsatile tinnitus with normal findings on otoscopy. CT scan was relatively insensitive in the detection of TS DAVF. MRI and MR/MRA were significantly more sensitive than CT. In the evaluation of patients with subjective pulsatile tinnitus, MRI/MRA defined anatomical abnormalities that may contribute to pulsatile tinnitus in 63% of patients.

CONCLUSIONS

In the absence of objective pulsatile tinnitus, MRI/MRA is an appropriate initial diagnostic step. When a patient has an objective bruit, the clinician may choose to proceed directly to angiography to make certain that a TS DAVF is not missed.

Phenidone prevents kainate-induced neurotoxicity via antioxidant mechanisms

Acculmulating evidence indicates that a marked generation of oxygen free radicals derived from the metabolism of arachidonic acid causes neurodegeneration. Recently, we have demonstrated that the novel antioxidant actions mediated by phenidone, a dual inhibitor of cyclooxygenase/lipoxygenase pathways, may play a crucial role in preventing neuroexcitotoxicity in vitro [Neurosci. Lett. 272 (1999) 91], and that phenidone significantly attenuates kainic acid (KA)-induced seizures via inhibiting the synthesis of Fos-related antigen protein [Brain Res. 782 (1998) 337]. In order to extend our understanding of the pharmacological intervention of phenidone, we evaluated the antioxidant activity of this compound in vivo in the present study. In order to better understand the significance of a blockade of both the cyclooxygenase and lipoxygenase pathways, we studied the effects of aspirin (ASP; a non-selective inhibitor of cyclooxygenase), NS-398 (a selective inhibitor of cyclooxygenase-2), esculetin (an inhibitor of lipoxygenase) and phenidone on lipid peroxidation, protein oxidation, and glutathione (GSH) status in the rat hippocampus after KA administration. ASP (7.5 or 15 mg/kg), NS-398 (10 or 20 mg/kg), esculetin (5 or 10 mg/kg) or phenidone (25, 50 or 100 mg/kg) was administered orally five times every 12 h before the injection of KA (10 mg/kg, i.p.). The KA-induced toxic behavioral signs, oxidative stress (lipid peroxidation and protein oxidation), impairment of GSH status, and the loss of hippocampal neurons were dose-dependently attenuated by the phenidone, NS-398+esculetin, and ASP+esculetin. However, ASP, NS-398 and esculetin alone failed to protect against the neurotoxicities induced by KA. Therefore, the results suggest that protection by blockade of both cyclooxygenase and lipoxygenase pathways against KA-induced neuroexcitotoxicity is via antioxidant actions. However, a novel anticonvulsant/neuroprotective effect mediated by phenidone remains to be further characterized.

Dual effects of dextromethorphan on cocaine-induced conditioned place preference in mice

Dextromethorphan (DM) at supra-antitussive doses might produce psychotomimetic effects in humans. In order to understand the underlying mechanisms responsible for the behavior induced by DM, we examined the effects of DM on cocaine-induced conditioned place preference (CPP) and locomotor pattern in mice, and Fos-related antigen immunoreactivity (FRA-IR) in the striatal complex (nucleus accumbens and striatum) of the mouse brain. The effects of DM (20 and 40 mg/kg, i.p.) on the CPP for 2.5, 5, 10, and 20 mg cocaine/kg, i.p. were assessed. Pretreatment with DM dose-dependently decreased the CPP for 20 mg cocaine/kg. Similarly, pretreatment with DM appeared to reduce the CPP for 10 mg cocaine/kg, but increase the CPP for 5 mg cocaine/kg. This finding was more pronounced for 2.5 mg cocaine/kg; DM significantly increased the CPP for 2.5 mg cocaine/kg in a dose-related manner. Furthermore, these results were correlated with alterations in the locomotor pattern (marginal activity) and FRA-IR in the striatal complex. Thus, our results suggest that DM exhibits a biphasic effect on the cocaine-induced CPP and locomotor pattern.

An immunocytochemical study of mitochondrial manganese-superoxide dismutase in the rat hippocampus after kainate administration

We examined the immunocytochemical distribution of mitochondrial Mn-superoxide dismutase (SOD-2) in the rat hippocampus after systemic injection of kainic acid (KA), in order to understand SOD-2-responsible antioxidant defense mechanism during the neurodegenerative process. SOD-2 immunostaining was more intense in CA3 pyramidal neurons than in CA1 neurons in the normal hippocampus. The immunoreactivity in region CA1 was reduced without significant neuronal losses within 12 h of KA injection. The CA1 and CA3 neurons lost their immunoreactivity, whereas SOD-2-positive glia-like cells proliferated, mainly throughout the CA1 sector, and had intense immunoreactivity 3 and 7 days after KA injection. This immunocytochemical distribution of SOD-2-positive non-neuronal elements was similar to that of glial fibrillary acidic protein (GFAP) and S-100 protein-positive cells. Activated microglial cells selectively marked with lectin occurred in the areas affected by the KA-induced lesion. Double-labeling immunocytochemistry showed the co-localization of SOD-2-positive non-neuronal cells and GFAP or S-100 protein-like immunoreactivity in the same cells. This suggests that astroglial cells mobilized to synthesize of SOD-2 protein in a response to KA toxicity designed to reduce the oxidative damage.

Prolonged exposure to cigarette smoke blocks the neurotoxicity induced by kainic acid in rats

We examined the effects of cigarette smoke (CS) on three parameters associated with kainic acid (KA)-induced neurotoxicity: seizure activity, cell loss in the hippocampus, and increased Fos-related antigen (FRA) expression. Animals were exposed to the main stream of CS from 15 Kentucky 2R1F research cigarettes containing 28.6 mg tar and 1.74 mg nicotine per cigarette, for 10 min a day, 6 days per week, for 4 weeks, using an automatic smoking machine. KA administration (10 mg/kg, i.p.) produced robust behavioral convulsions lasting 4-5 h. Pre-exposure to CS significantly reduced the seizures, mortality, and severe loss of cells in regions CA1 and CA3 of the hippocampus after KA administration. Consistently, pre-exposure to CS significantly attenuated the KA-induced increased FRA immunoreactivity in the hippocampus. In contrast, pretreatment with central nicotinic antagonist, mecamylamine (2 or 10 mg/kg, i.p.) blocked the neuroprotective effects mediated by CS in a dose-dependent manner. These results indicate that CS exposure provides neuroprotection against the KA insult via nicotinic receptor activation.

Characterization of gastrointestinal bleeding in severely ill hospitalized patients

OBJECTIVE

To characterize the source of bleeding and the prognosis in critically ill patients with upper gastrointestinal hemorrhage that developed while in the hospital.

SETTING

Intensive care units of a large academic tertiary-care center.

DESIGN

Retrospective cohort study.

SUBJECTS

Patients undergoing endoscopy in intensive care units for gastrointestinal bleeding that developed while in the hospital.

MEASUREMENTS AND MAIN RESULTS

Medical records were available for 142 patients. Of these, 66 met the criteria for in-hospital bleeding. Peptic ulcer disease, present in 56% of patients, was the most common bleeding source identified. Of patients with peptic ulcer disease, nine of 37 (24%) had stigmata of recent hemorrhage. Ten patients (15%) received endoscopic hemostasis interventions (eight receiving therapy for bleeding ulcers, two receiving therapy for esophageal varices). The in-hospital mortality rate was 42%. The cause of death was sepsis and/or multiple system organ failure in 21 patients (75%); the gastrointestinal bleeding may have contributed to the onset of sepsis in one of these patients. No patients died directly of gastrointestinal bleeding.

CONCLUSIONS

Critically ill patients who bleed while in the hospital have similar sources of bleeding and rates of endoscopically directed therapy as patients admitted to hospital with bleeding. The mortality rate is very high in patients with bleeding that develops in the hospital, and this is usually a result of systemic disease. These data may help clinicians and patients to estimate the potential benefit of urgent endoscopy in critically ill patients.

Protection of methamphetamine nigrostriatal toxicity by dietary selenium

Multiple dose administration of methamphetamine (MA) results in long-lasting toxic effects in the nigrostriatal dopaminergic system. These effects are considered to be primarily due to oxidative damage mediated by increased production of hydrogen peroxide or other reactive oxygen species in the dopaminergic system. The present study was designed to determine the protective effects of dietary antioxidant selenium on MA-induced neurotoxicity in the nigrostriatal dopaminergic system. Male C57BL/6J mice were fed either selenium-deficient (< 0.01 ppm Se) or selenium-replete (0.2 ppm Se) diets for 90 days. MA treatment decreased the dopamine (DA) levels in the striatum and substantia nigra (SN) of both Se-replete and Se-deficient animals. However, in Se-replete animals, this DA depletion was significantly attenuated in both the striatum and SN. A novel observation is that MA administration resulted in increased activity of Cu,Zn-SOD in the brains of both Se-deficient and Se-replete animals. However, MA administration to Se-deficient animals exhibited a higher Cu,Zn-SOD activity in the nigrostriatal system than the control animals. Elevated malondialdehyde (MDA) levels in the striatum and SN were also observed in Se-deficient MA-treated animals. Se repletion significantly increased the glutathione peroxidase (GPx) activity and the ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) in the MA-treated animals. In conclusion, we have shown that dietary Se attenuated methamphetamine neurotoxicity and that this protection involves GPx-mediated antioxidant mechanisms. Even though Cu,Zn-SOD activity was significantly elevated by MA treatment, the role of this enzyme in MA-mediated neurotoxicity is not yet clear.

Detoxifying chlorine rich gas streams using solid supported nickel catalysts

Catalytic hydrogen treatment is presented as a viable low energy means of treating/detoxifying concentrated chlorinated gas streams to generate recyclable raw materials. Nickel (1.5% w/w and 15.2%) loaded silica and nickel (2.2% w/w) exchanged Y zeolite catalysts have been used to hydrotreat a range of chlorophenols (CPs), dichlorophenols (DCPs), trichlorophenols (TCPs) and pentachlorophenol (PCP) over the temperature interval 473 K</=T</=573 K. In every instance the nickel catalysts were 100% selective in cleaving the chlorine component from the ring, leaving the aromatic nucleus and hydroxyl substituent intact. The effects of varying process time and temperature are considered in terms of phenol yield and the ultimate partitioning of chlorine in the parent organic and product inorganic hosts. Chlorine removal rates, hydrodechlorination selectivity and apparent activation energies are also provided. Prolonged exposure of the catalysts to the concentrated chlorine gas streams resulted in an irreversible loss of activity which is related to the total concentration of chlorine that had been hydroprocessed. Hydrodechlorination proceeds via irreversible stepwise and/or concerted routes as is illustrated for the treatment of 2,3,5-TCP. Increasing the nickel content was found to raise the overall detoxification efficiency while the use of a zeolite support introduced spatial constraints which had a strong bearing on process selectivity.

Dextromethorphan modulates the AP-1 DNA-binding activity induced by kainic acid

We have recently reported that dextromethorphan attenuates the neurotoxicity induced by kainic acid in a dose-related fashion. Pretreatments with dextromethorphan (50 mg/kg, p.o. x2) significantly reduced the activator protein-1 DNA-binding activity and the Fos-related antigen-immunoreactive protein induced by kainic acid (10 mg/kg, i.p.) in the CA1, but not the CA3 or the dentate gyrus sector of the rat hippocampus. Paradoxically, dextromethorphan itself caused an elevated activator protein-1 DNA-binding activity and Fos-related antigen-immunoreactive protein in the CA1 region which lasted for at least 4 days. The results suggest that the CA1 area is the critical site for mediating the putative neuroprotective effect induced by dextromethorphan.

A cost-effective and rational surgical approach to patients with snoring, upper airway resistance syndrome, or obstructive sleep apnea syndrome

The past decade has seen several innovations in the surgical techniques available for treatment of patients with sleep-disordered breathing. Outpatient techniques such as laser-assisted uvulopalatoplasty (LAUP) and more aggressive procedures designed to address hypopharyngeal and base of tongue obstruction (genioglossus advancement and hyoid myotomy) have been developed and proven successful. We describe the efficacy of LAUP for snoring (72.7%), upper airway resistance syndrome (81.8%), and mild (mean [+/-SD] respiratory disturbance index [RDI] = 12 +/- 8.1) obstructive sleep apnea (41.7%) in 56 patients who underwent 132 LAUP procedures in a 26-month period. Thirty-two patients with more significant obstructive sleep apnea (mean RDI = 41.8 +/- 23.1) underwent multilevel pharyngeal surgery consisting of genioglossus advancement and hyoid myotomy combined with uvulopalatopharyngoplasty. The surgical success rate in this group of patients was 85.7% when commonly accepted criteria were applied. We recommend a stratified surgical approach to patients with sleep-disordered breathing. Progressively worse airway obstruction marked by multilevel pharyngeal collapse and more severe sleep-disordered breathing is treated with incrementally more aggressive surgery addressing multiple areas of the upper airway.

Transcription of the blk gene in human B lymphocytes is controlled by two promoters

Genomic DNA containing the first exon and 5'-flanking region of the human protein tyrosine kinase, blk, was isolated. Sequence analysis identified a TG repeat element in this region with enhancer activity, but no TATA or CCAAT sequences were found. Two blk transcripts of 2.2 and 2.5 kilobases were identified in various B-cell lines by Northern blot analyses, and primer extension experiments demonstrated two clusters of multiple transcription start sites. Subsequent promoter analyses by transient transfection assays with a reporter gene identified two promoter elements in the human blk gene. Promoter P1 contains sequences that have been shown to regulate the expression of immunoglobulin genes and promoter P2 contains elements that are highly conserved in the promoter of major histocompatibility complex class II genes, as well as a B-cell-specific activator protein- (BSAP) binding site. Electrophoretic mobility shift assays demonstrated that the binding of a protein to the BSAP-binding site was correlated with the presence of the 2.5-kilobase blk transcript. These data suggest that the two human blk RNAs arise from the transcription of the blk gene by two distinct promoters and that these promoters may be subject to regulation by different trans-acting factors.

Transient absorption spectra and quenching of coumarin excited states by nucleic acid bases

Triplet-triplet absorption spectra of coumarin show different profiles and maxima in ethanol from those in water, which are very similar to those reported in benzene. Long-lived transient species other than triplet states were generated as initial photoproducts between coumarins and nucleic acid bases. The excited singlet and triplet states of coumarins were quenched by nucleic acid bases. Adenine base quenched the excited singlet state of coumarins more efficiently than thymine base. However, photocycloadducts of furocoumarins are formed predominantly with thymine, and not with adenine. Moreover, it is reported that the poly[dA-dT].poly[dA-dT] sequence region is the most favourable site for the photocycloaddition reaction of furocoumarins. The results imply that adenine contributes to singlet-state photocycloaddition reaction of furocoumarins with thymine, probably through an adenine-furocoumarin-thymine termolecular interaction.