The effect of hyperbaric oxygen therapy of oral mucosal carcinoma

Hyperbaric oxygen is sometimes used in the course of treatment in head and neck cancer patient. This study was undertaken to investigate the effect of hyperbaric oxygen on oral cavity carcinogenesis in an animal model. Dimethylbenzanthracene was applied three times weekly to induce oral squamous cell cancers. The group that received simultaneous hyperbaric oxygen had fewer tumors, but the tumors were larger than the dimethylbenzanthracene-only group. We concluded that hyperbaric oxygen has a tumor-suppressive effect during the induction phase of oral carcinoma and appears to have a stimulatory effect during the proliferative phase of carcinoma in this animal model.     

Randomized, prospective double-blind trial of metoclopramide and placebo for gastroesophageal reflux in infants

The effect of metoclopramide on gastroesophageal reflux was studied in 30 infants less than 1 year of age. Gastroesophageal reflux was documented in all infants by extended pH monitoring before enrollment in the study. Patients were randomly assigned to receive metoclopramide 0.1 mg/kg or placebo four times a day, 1/2 hour before feeding for 1 week, followed by the alternate regimen for 1 week. The infants were reevaluated with extended pH monitoring and scintigraphy after 4 to 7 days of each treatment. A symptom score was derived by determining the average number of occurrences of all symptoms recorded daily by parents on a symptom checklist during pretreatment, placebo, and metoclopramide treatment periods. There was a difference between pretreatment evaluation and placebo periods with respect to daily symptom scores (p less than 0.005), reflecting a significant placebo response. However, no difference in scintigraphic study was found between placebo and metoclopramide periods. A significant difference between placebo and metoclopramide periods was noted in the percentage of time esophageal pH was less than 4.0 (p less than 0.001). However, although metoclopramide decreased the proportion of time esophageal pH was less than 4.0, pH remained less than 4.0 for more than 5% of the time in most patients. Substratification of the total group into infants younger and older than 3 months revealed that older infants had greater average daily weight gain during the metoclopramide treatment period (34.3 gm/day) than in the placebo treatment period (6.6 gm/day, p = 0.05). We conclude that metoclopramide in the dosage 0.1 mg/kg four times daily reduces reflux in infants and may be useful for infants with poor weight gain and other serious complications of gastroesophageal reflux.     

Object activation in semantic memory from visual multimodal feature input.

The human brain's representation of objects has been proposed to exist as a network of coactivated neural regions present in multiple cognitive systems. However, it is not known if there is a region specific to the process of activating an integrated object representation in semantic memory from multimodal feature stimuli (e.g., picture-word). A previous study using word-word feature pairs as stimulus input showed that the left thalamus is integrally involved in object activation (Kraut, Kremen, Segal, et al., this issue). In the present study, participants were presented picture-word pairs that are features of objects, with the task being to decide if together they "activated" an object not explicitly presented (e.g., picture of a candle and the word "icing" activate the internal representation of a "cake"). For picture-word pairs that combine to elicit an object, signal change was detected in the ventral temporo-occipital regions, pre-SMA, left primary somatomotor cortex, both caudate nuclei, and the dorsal thalami bilaterally. These findings suggest that the left thalamus is engaged for either picture or word stimuli, but the right thalamus appears to be involved when picture stimuli are also presented with words in semantic object activation tasks. The somatomotor signal changes are likely secondary to activation of the semantic object representations from multimodal visual stimuli.     

Correlation of reaction time in and out of the functional MR unit

RATIONALE AND OBJECTIVES: The authors performed this study to determine whether reaction times (RTs) recorded in the functional magnetic resonance (MR) imaging environment reflect the performance of the patient outside the imaging room. MATERIALS AND METHODS: Fifteen healthy control subjects (mean age, 61.6 years) performed a simple reaction time (SRT) task outside the MR magnet and a visuomotor response time task inside the magnet with use of block-design and event-related paradigms. For both behavioral and functional MR imaging tests, subjects tapped the right index finger upon the appearance of a visual cue. The mean RTs for out-of-magnet and functional MR imaging paradigms were compared. Results. There was a statistically significant difference in RTs between block-design and single-event paradigms (t = 3.458, P < .004). The RT values during functional MR imaging and SRT tasks did not show significant differences (.65 < P < .7, paired t test). However, no correlation was found in RT values between event-related (p = -0.004, P = .15) or block-design (p = 0.03, P = .13) paradigms and SRT data. With the block-design functional MR imaging paradigm, the RT was significantly faster (P < .0003) at the beginning of the session than the end, illustrating the effect of anticipation. CONCLUSION: Functional MR imaging RTs must be used to determine the correlation between subjects' performance and the volume of brain activation in a functional MR imaging experiment. The effect of anticipation should be minimized, which could best be achieved by using event-related paradigms.     

Neurotologic skull base surgery in pediatric patients.

OBJECTIVE: Innovations in diagnosis, surgical techniques, and perioperative care have dramatically improved outcomes in lateral skull base procedures in recent years. There is a belief, however, that children with skull base tumors have yet to benefit from these technological and procedural advances. The purpose of this study is to provide a clinical review of neurotologic skull base surgery in the pediatric population. STUDY DESIGN: Retrospective case review. SETTING: Private practice tertiary referral center. PATIENTS: Eighty-nine pediatric patients undergoing 115 neurotologic procedures for lateral skull base tumors from July 1992 to September 2003. MAIN OUTCOME MEASURES: Initial clinical presentation, tumor type, pre- and postoperative hearing and facial nerve status, treatment course, complications, and functional outcomes. RESULTS: The majority of tumors in this series were vestibular schwannomas, and 65 patients were diagnosed with neurofibromatosis Type 2. Surgical approaches included 70 middle fossa, 40 translabyrinthine, 2 transcochlear, 2 infratemporal fossa, and 1 retrosigmoid craniotomy. Complete tumor removal was accomplished in the majority of cases (97%), with good preservation of facial nerve function (House-Brackmann Grade I or II) in 80% of patients. In patients undergoing middle fossa surgery for hearing preservation, measurable hearing was preserved in 61.4% of cases. The incidence of complications was low. CONCLUSION: With advances in diagnostic procedures and use of current neurotologic techniques, pediatric patients may undergo successful treatment of lateral skull base tumors, with good functional outcomes and minimal morbidity.     

Parkinson's disease, CYP2D6 polymorphism, and age

OBJECTIVE: PD may be caused by genetic susceptibility to neurotoxins. CYP2D6 is a candidate gene for PD because it regulates drug and toxin metabolism, but association studies have been inconsistent. The aim of this study was to test if the CYP2D6*4 allele (poor metabolizer phenotype) is associated with earlier age at onset. METHODS: Five hundred seventy-six patients with PD and 247 subjects without PD were studied using standard diagnostic, genotyping, and statistical techniques. RESULTS: Surprisingly, mean onset age was significantly later in *4-positive patients. Frequency of *4 was significantly higher in late-onset PD than early-onset PD. When early- and late-onset PD were analyzed separately, *4 had no effect on onset age; hence, the association with delayed onset was likely an artifact of an elevated *4 frequency in late-onset PD. Contrary to a common assumption that CYP2D6 frequencies do not change with age, *4 frequency rose significantly with advancing age, both in patients with PD (from 0.16 at mean age of 56.5 years to 0.21 at mean age of 72) and subjects without PD (from 0.09 at mean age of 45.5 years to 0.21 at mean age of 72). *4 Frequencies in patients with early- and late-onset PD, although different from each other, were in agreement with similarly aged subjects without PD, suggesting the elevated *4 frequency in late-onset PD was likely an age effect, unrelated to PD. CONCLUSION: The CYP2D6*4 allele is not associated with earlier PD onset. *4 May be associated with survival. Inconsistent results from allelic association studies may have been due to an unrecognized age effect.     

Expression of tissue factor pathway inhibitor in human fetal and placental tissues

The coagulation system differs markedly between fetuses, neonates, and adults, and fetal and neonatal thrombotic abnormalities are poorly understood. Tissue factor pathway inhibitor (TFPI) is an important inhibitor of the extrinsic pathway of coagulation. To begin examining the role of TFPI in the maternal-fetal relationship, TFPI expression in human fetal and placental tissues was studied by immunohistochemical staining. TFPI was widely expressed in human fetal tissues from 8-24 weeks gestation, particularly in epithelial and endothelial tissues. Fetal liver, lung, kidney, and intestine were notably positive for TFPI staining. Within the tissues, TFPI was expressed in pneumocytes, hepatocytes, renal tubular and glomerular cells, muscle fibers, and enterocytes. In placental tissues, TFPI was expressed in syncytiotrophoblasts, cytotrophoblasts, vascular endothelium, and extravillus trophoblasts from 10 weeks through term. Advancing gestation had little effect on TFPI expression. Further studies are needed to determine the functional role of TFPI in fetal and placental tissues and to define perturbations in its expression during fetal and neonatal disease states.