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.     

Visual outcome and success of amblyopia treatment in unilateral small posterior lens opacities and lenticonus initially treated nonsurgically.

PURPOSE: We sought to assess the success of amblyopia treatment in patients with small posterior lens opacities as well as the factors associated with a good visual outcome. METHODS: This was a retrospective study of patients with posterior lens opacities that initially were thought to be too small in size to warrant cataract surgery. The following variables were examined: cataract type, location, diameter, persistent hyaloid vessel, anisometropia, strabismus, and age of detection. Success of treatment of amblyopia was defined as improvement by at least 0.3 logMAR units. Good visual outcome was defined as 20/40 or better. Amblyopia was treated by glasses, patching, and/or atropine. Patients who failed with conservative treatment or had an increase in cataract size underwent surgery. RESULTS: Forty-eight (91%) of 53 eyes were amblyopic. Thirty amblyopic eyes had pre- and post-treatment Snellen acuities. Twenty (67%) had their visual acuity (VA) improved by 0.3 logMAR units or greater. None of the measured variables were associated with successful amblyopia treatment. Twenty-five (49%) of 51 patients had a final VA of 20/40 or better. The only variable associated with good visual outcome was cataract type: 18 of 25 (72%) posterior subcapsular cataract and 6 of 23 (32%) posterior lenticonus eyes achieved VA of 20/40 or better (P = 0.008). Six patients who went on to have cataract surgery experienced a larger improvement in BCVA (4.50 logMar units +/- 2.52 lines) compared with patients treated without cataract surgery (2.36 logMar units +/- 3.11 lines). DISCUSSION: Amblyopia treatment was successful in most cases. A small group of patients who underwent cataract surgery experienced a greater VA improvement; however, it was not statistically significant. Further studies are needed to determine which patients would benefit from cataract surgery.     

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.     

Smoking increases facial skin flap complications

This study was undertaken to determine whether smokers have a higher risk of complications after reconstruction of facial skin defects. Ninety-one patients with facial skin defects reconstructed with local flaps were reviewed retrospectively. Thirty-eight (42%) were active smokers, 12 (13%) had not smoked for at least 1 year prior to surgery, and the rest were nonsmokers. Complications occurred in 23 patients (25%; 37% in smokers, 17% in ex-smokers, and 17% in nonsmokers; p < .03). All full-thickness skin losses and all cellulitis occurred in active smokers. We conclude that active smokers are at a higher risk for complications in facial skin flap surgery. That ex-smokers had a complication rate similar to that of nonsmokers suggests that part of smoking's adverse effect on skin flaps may be an acute phenomenon, and that smoking cessation for shorter (<1 year) periods of time before surgery may have a beneficial effect.     

Production of granulocyte colony-stimulating factor by the human placenta at various stages of development

The human placenta is capable of producing a variety of haematopoietic growth factors in vitro. It is not clear, however, whether the placenta produces such factors in vivo and if so, whether placental production of haematopoietic growth factors has a physiological role in fetal haernatopoietic development. As a step toward making this determination, we assessed whether the onset of placental production of granulocyte colony-stimulating factor (G-CSF), in vivo, coincides with the onset of granulocytopoiesis in the developing fetus. To make this assessment, we obtained human placentae between 10 weeks of gestation and term and studied production of G-CSF in several ways. First, we sought to determine whether the onset of production of G-CSF mRNA in the placenta immediately precedes the appearance of neutrophil development in the fetus. Second, we assessed the effect of gestational age on the capacity of the placenta to generate G-CSF in vitro, by incubating cubes of placenta, with or without including interleukin-la (IL-1α) in the culture media, and quantifying G-CSF in the cell culture supernatants 24h later. Third, we assessed the rate of G-CSF production by the placenta, by perfusing two normal, term placentae using a membrane-oxygenator system, and quantifying G-CSF, at intervals, in the perfusates. We found: (1) no evidence that placental production of G-CSF is involved in regulating granulocytopoiesis in the fetus, (2) that the healthy placenta contains little or no G-CSF mRNA in vivo, (3) the placenta at term has a far greater capacity to produce G-CSF, when stimulated, than does the placenta before term, and (4) that although the placenta does not normally produce G-CSF in vivo, it has the capacity of generating very large quantities of G-CSF continuously over at least several days.     

Methamphetamine's effect on repeated acquisitions with serial discrimination reversals

Rats were trained through a series of discrimination reversals until they developed a stable, repeated acquisition baseline. Methamphetamine (0.5 mg/kg) accelerated acquisition measured from this baseline. The drug effect was demonstrated with successive cumulative records and with a graphic method using a distribution of error scores to develop a baseline. Generally, with low doses(0.25–0.50), methamphetamine reduced errors without affecting rewarded responding. This effect is dose dependent, although at 1.0 mg/kg the drug may disrupt operant behavior.Experiments I and II were conducted while the author was an NSF Science Faculty Fellow at Indiana University. Facilities were provided by the Psychopharmacology Laboratory supported by USPHS Grant MH-14658 to Dr. G. A. Heise. Experiment III was conducted at the University of Tennessee.     

Urologic diseases in America project: urinary incontinence in women-national trends in hospitalizations, office visits, treatment and economic impact

PURPOSE: We describe temporal trends in hospitalizations, outpatient visits and the treatment of female urinary incontinence (UI), and estimated the costs of incontinence using national databases. MATERIALS AND METHODS: The analytic methods used to generate these results have been described previously. RESULTS: The rate of hospitalization with a primary diagnosis of UI decreased from 51/100,000 women in 1994 to 44/100,000 in 2000 and mean length of stay decreased from 3.1 days to 2.1. In contrast, outpatient visits for UI more than doubled during the same period from 845/100,000 women to 1,845/100,000. Rates of inpatient surgical treatment for UI decreased slightly from 1994 to 2000, while ambulatory surgical center visit rates for Medicare beneficiaries 65 years or older more than doubled from 60/100,000 in 1992 to 142/100,000 in 1998. Medical expenditures for UI increased substantially during the 1990s, almost doubling from 128.1 million dollars in 1992 to 234.4 million dollars in 1998 for Medicare beneficiaries 65 years or older. This increase was due almost entirely to increased outpatient costs, which increased from 25.4 million dollars or 9.1% of total costs in 1992 to 329 million dollars or 27.3% of total costs in 2000 in this group. CONCLUSIONS: While existing national databases generally capture only the minority of incontinent women with UI who seek and receive care for UI, they are useful for documenting treads in service use and surgical treatments, and estimating economic impact. This data can be helpful when formulating public policy and designing observational and clinical studies.