Reduced FOV diffusion tensor MR imaging and fiber tractography of pediatric cervical spinal cord injury.

STUDY DESIGN: Quantitative study. OBJECTIVES: To evaluate the effectiveness of pediatric spinal cord diffusion tensor tractography (DTT) generated from reduced field of view diffusion tensor imaging (DTI) data and investigate whether there are differences in these values between typically developing (TD) subjects and patients with spinal cord injury (SCI). SETTING: Temple University Hospital and Shriners Hospitals for Children-Philadelphia, USA. METHODS: A total of 20 pediatric subjects including 10 healthy subjects (age 15.13±3.51 years (mean±s.d.) and age range 11-21 years) and 10 subjects with SCI in the cervical area (age 13.8±3.26 years and age range 8-20 years) were recruited, and scanned using a 3.0T MR scanner. Quantitative parameters of DTI and fiber tracking, such as mean fractional anisotropy (FA), apparent diffusion coefficient (ADC), mean length of fiber tracts and tract density, were calculated for each subject. RESULTS: Subjects with SCI showed reduced FA and tract density, and increased ADC values and length of fiber tracts, compared with controls. Statistically significant differences were seen in FA (P=0.0238) and tract density (P=0.0005) between controls and subjects with SCI, whereas there were no significant differences in ADC values and length of fiber tracts. The tractography visually showed that the white matter tracts (blue color) of the SCI patients were overall less abundant and less organized compared with control cases. CONCLUSION: The results show that DTI and DTT could be used as surrogate markers for quantification and visualization of the injured spinal cord.

Kleine-Levin syndrome: a unique cause of fatigue in an athlete.

Kleine-Levin syndrome (KLS) is a rare disorder characterised, most notably, by periodic episodes of hypersomnolence and hyperphagia. Associated features of the disorder include a lack of concentration, mood changes, and anxiety. Laboratory tests may show slight changes in the electroencephalogram. However, clinical presentation and laboratory tests are normal during asymptomatic intervals. KLS most often presents in adolescent males, with complete recovery by the 3rd to 4th decade of life. Possible precipitating factors include excessive workload, febrile illness, and respiratory infections. Presented is a classical case of KLS in an adolescent male athlete. The patient's history, complete laboratory results, and symptoms are discussed. Possible treatments for this disorder are also mentioned, along with diagnostic criteria.

The impact of imagining personalized versus standardized urge scenarios on cigarette craving and autonomic reactivity.

A cue-reactivity paradigm was used to investigate the effects of personalizing imagery materials on smokers' reactivity to smoking cues. Cigarette smokers (n = 60) described situations used to create 4 personalized imagery scripts: positive mood/urge, positive mood/no urge, neutral mood/urge, and neutral mood/no urge. Their reactivity to these scripts as well as 4 standardized imagery scripts and 4 personalized scripts of another smoker was assessed. Personalization led to greater vividness, positive mood, and relevance ratings compared with the other 2 script types. Personalization of urge material did not enhance craving beyond that generated by the other 2 script types but did suppress craving under no-urge conditions. Findings stand in contrast to current conceptualizations of craving regarding the proposed impact of personalization on craving and suggest alternative mechanisms by which imagery cues influence craving generation.

Associative and non-associative fentanyl tolerance in the rat: evaluation of cross tolerance with mu-and kappa-specific opioids.

RATIONALE: Associative tolerance to the analgesic effects of morphine is most pronounced when morphine is paired with a distinctive context at a long interdose interval (IDI). In contrast, morphine administered at a short IDI promotes the development of non-associative tolerance and disrupts the acquisition of associative tolerance. The impact of IDI on the development of associative tolerance to opioids other than morphine has not been investigated previously. OBJECTIVES: This research examined associative and non-associative tolerance to the analgesic effects of fentanyl in rats. Cross tolerance for these two forms of tolerance with morphine (mureceptor agonist) and U50,488H (kappa-receptor agonist) analgesia was also investigated. METHODS: Animals were given eight fentanyl injections (0.10 mg/kg) paired or unpaired with a distinctive context at either a 3-h (short) or 96-h (long) IDI. Subjects were then tested for tolerance in the distinctive context using the tail-flick procedure and dose-response curve methodology. RESULTS: At the short IDI, animals developed non-associative tolerance to fentanyl that was receptor specific, i.e., cross tolerant with morphine analgesia but not with U50,488H analgesia. At the long IDI, fentanyl-tested animals displayed tolerance that appeared to be controlled primarily by associative processes. This associative form of tolerance was also receptor specific, displaying cross tolerance with morphine but not with U50,488H. CONCLUSIONS: The impact of IDI on the development of non-associative and associative fentanyl tolerance is consistent with findings obtained with morphine showing that conditions conducive to the development of non-associative tolerance disrupt the acquisition of associative tolerance. The cross-tolerance data, however, did not parallel previous research examining the cross-tolerance profiles of associative and non-associative morphine tolerance.

Selection of protective action guides for nuclear incidents. EPA.

In 1991 the Environmental Protection Agency (EPA) published its revised Manual of Protective Action Guides and Protective Actions for Nuclear Incidents. The protective action guides contained in the manual represent EPA's formal recommendations to Federal, State, and local emergency response officials for protecting public health and safety during a nuclear incident. These guides are expressed in terms of the projected dose at which action(s) should be taken to reduce or eliminate that dose. In determining the appropriate values for the protective action guides, the Agency considered the following four principles: (1) acute health effects should be avoided, (2) the risk of delayed health effects should be minimized, (3) the values should not be higher than justified by a cost-benefit analysis, and (4) the risk to health from implementing the protective action should not be greater than the risk from the dose avoided. This paper examines each of these principles and their application in the selection of the evacuation and sheltering protective action guides for the early, or immediate, phase of a nuclear incident.

The impact of imagining completed versus interrupted smoking on cigarette craving.

A brief imagery procedure was used to determine the effects of imagining completed versus interrupted smoking on self-reported craving, mood, autonomic functioning, and reaction time to an auditory probe. Cigarette smokers (N = 60) imagined actively participating in 3 types of scenarios in which they (a) engaged in smoking behavior, (b) attempted to smoke but were interrupted by a lack of cigarettes, and (c) were not confronted with smoking cues. Imagining both completed and interrupted smoking produced equivalent increases in craving compared with imagining neutral scenarios. Imagery of interrupted smoking was associated with higher heart rate and increased negative mood relative to the other scenario types, whereas imagery of completed smoking was associated with slower reaction time on the probe reaction-time task. Theoretical and methodological implications of the results are discussed.

Hydrogen peroxide causes significant mitochondrial DNA damage in human RPE cells.

Retinal pigment epithelial cell dysfunction mediated by reactive oxygen intermediates has been suggested as a possible cause of age-related macular degeneration. To test the hypothesis that retinal pigment cells are susceptible to genetic damage mediated by reactive oxygen intermediates, retinal pigment epithelial cells were treated with 50 micrometers-200 micrometers of hydrogen peroxide in vitro. Damage to mitochondrial DNA and three nuclear loci were assessed using quantitative polymerase chain reaction. Hydrogen peroxide treatment of retinal pigment epithelial cells resulted in significantly increased mitochondrial DNA damage. Significant mitochondrial DNA damage occurred rapidly and was not completely repaired within 3 hr post-treatment. By contrast, no DNA damage was observed in three different nuclear loci (beta-globin gene cluster, hprt, and beta- polymerase genes). Hydrogen peroxide treatment of retinal pigment epithelial cells also resulted in decreased mitochondrial redox function compared to controls, consistent with increased mitochondrial DNA damage. Consequently, retinal pigment epithelial cell mitochondrial DNA appears susceptible to hydrogen peroxide mediated damage in vitro, and thus, may serve as a catalyst in the initial events leading to retinal pigment epithelial cell dysfunction in vivo.

Identification and localization of neurohypophysial peptides in the brain of a caecilian amphibian, Typhlonectes natans (Amphibia: Gymnophiona).

The amphibian order Gymnophiona contains more than 150 different species of caecilians. The characterization and distribution of neurohypophysial peptides, however, has not been described for any member of this order. By using high-performance liquid chromatography, radioimmunoassay, and mass spectrometry, we identified the peptide arginine vasotocin (AVT) in brain and pituitary extracts from the caecilian Typhlonectes natans. By using immunocytochemistry, we found five populations of AVT-immunoreactive (AVT-ir) cells in the brain of T. natans. AVT-ir cell bodies were located in the preoptic area, amygdala pars medialis, ventral thalamus, dorsal hypothalamic nucleus, and nucleus of the solitary tract. AVT-ir fibers and terminal fields were widespread. We also identified a mesotocin-like peptide. The distribution of this peptide in the brain of T. natans was more restricted than the distribution of AVT. Mesotocin-like-immunoreactive cell bodies were located almost exclusively in the preoptic area, with only a few other cells located in the amygdala pars medialis. This caecilian species, therefore, possesses neurohypophysial peptides that are similar in their structure and distribution to the peptides found in anuran and urodele amphibian orders.

Correlates of functioning in a population with dual diagnoses: an examination of diagnosis and problem history.

This study examines the relationship between diagnosis and life functioning using the Addiction Severity Index (ASI) with 467 hospitalized individuals with mental illness and substance abuse problems. Persons diagnosed with schizophrenia were the best functioning group across most of the ASI domains except employment and psychiatric functioning. More robust relationships were found between problem history (i.e., prior symptomatology or treatment) and current functioning. Respondents with histories of drug treatment, prior experience of anxiety and depression, self-injurious behavior, or violence control problems experienced more severe medical, drug, alcohol, psychiatric, legal, and family/social problems at the time of hospitalization. Violence control problems were related to drug use and criminal involvement, whereas self-injurious behavior was more often related to alcohol use and psychiatric distress. These findings suggest that problem history may be a stronger predictor of treatment need at the time of hospital entry than are more commonly used indexes, such as diagnosis.

Purification and structural characterization of insulin from a caecilian, Typhlonectes natans (Amphibia: Gymnophiona).

Despite the important position of amphibia in phylogeny, efforts at the structural characterization of amphibian neurohormonal peptides have largely been confined to the Anurans (frogs and toads). Insulin was purified from an extract of the pancreas of the caecilian, Typhlonectes natans. The primary structure of the peptide was established as: [formula: see text] This amino acid sequence contains several unusual substitutions (Gln-->Lys at A5, His-->Leu at A8, Gln-->Glu at A15, and Gly -->Ala at B20) that are not present in other amphibian insulins. The structure of insulin appears to be less well conserved among the different orders of amphibia, compared with reptiles and birds.

Medicare: trends in reimbursing hospital dental practices.

A survey of dentists working in hospitals found that dental procedures covered under Medicare are not equally reimbursed. Lack of uniform guidelines, appropriate interpretation and universal claim forms lead to problems. Most respondents favor medically adjunctive dental care in the national health care reform.

Splenic artery aneurysm rupture in pregnancy with maternal and fetal survival. A case report.

A splenic artery aneurysm occurred at 30 weeks, 3 days' gestation. Both the mother and fetus survived.

Actinomycosis: an unusual complication following appendicitis.

We present a report of a case of retroperitoneal actinomycosis 3 years after appendectomy for a ruptured appendix. Actinomycosis is an unusual infectious disease that occasionally occurs after enteric perforation. The literature is reviewed, and the pathogenesis, diagnosis, and treatment are discussed.

Determinants of wound infection incidence after isolated coronary artery bypass surgery in patients randomized to receive prophylactic cefuroxime or cefazolin.

In this open-label, randomized drug study, we compared two cephalosporin prophylactic regimens, one using cefazolin and one using cefuroxime, in 100 patients having coronary bypass surgery. Additional epidemiological data were collected to identify the patient at higher risk for acquiring an infection. Patients were categorized into four groups: (1) no infection; (2) clinically determined infection without a culture or prescription of additional antibiotics; (3) clinical infection with no or negative wound culture and prescription of additional antibiotics; and (4) clinical infection with positive culture and need for additional antibiotics. Seven cefuroxime patients (13.5%) and 9 cefazolin patients (18.8%; p = 0.471) had a wound that became clinically infected (Groups 2-4). In a univariate analysis, 11 variables were statistically associated with the development of a wound infection. A logistic regression model defined 3 variables at an alpha level of 0.05 and 3 at an alpha level of 0.10 that predicted a wound infection. Patients were identified at high risk of wound infection if they had postoperative weight gain, long operative hospitalization, prolonged use of a Foley catheter, postoperative use of blood products, and operation performed by two specific surgeons. Our results indicated that closer observation of the high-risk patients and a definition of the mechanism of the infections are needed.

Comparison of esmolol and nitroprusside for acute post-cardiac surgical hypertension.

Because acute systemic hypertension early after cardiac surgery has been linked to catecholamine elevation, an open-label, randomized, crossover study was performed to compare the efficacy of esmolol, a new ultra-short-acting intravenous beta-blocking agent, to nitroprusside, the standard therapy. Controlled drug infusions to maximal dosage (esmolol, 300 micrograms/kg/min, and nitroprusside, 10 micrograms/kg/min) were titrated to achieve at least a 15% reduction in systolic pressure. The blood pressure (BP) endpoint was achieved with esmolol (within 29 +/- 14 minutes) in 18 of 20 patients (90%), compared with 19 of 20 (95%) with nitroprusside infusion (within 21 +/- 15 minutes, difference not significant [NS]). Systolic BP decreased from 170 +/- 13 to 136 +/- 12 mm Hg (mean +/- standard deviation) with esmolol and from 170 +/- 13 to 141 +/- 13 mm Hg with nitroprusside infusion (both p less than 0.05). Diastolic BP was reduced from 71 +/- 12 to 64 +/- 11 mm Hg with esmolol and from 71 +/- 12 to 52 +/- 13 mm Hg with nitroprusside infusion (both p less than 0.05). Esmolol infusion resulted in decreased heart rate, cardiac index and stroke volume index and increased right atrial pressure (all p less than 0.05), whereas nitroprusside infusion resulted in increased heart rate and cardiac index and decreased right atrial pressure, pulmonary arterial wedge pressure and systemic vascular resistance (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Use of esmolol in hypertension after cardiac surgery.

Systolic hypertension, which is common soon after cardiac surgery, increases cardiac work and may threaten fresh vascular anastomoses. Because postoperative hypertension is often associated with elevated catecholamines and preoperative use of beta-blocking agents, esmolol, an ultrashort-acting beta-blocking agent, was compared with nitroprusside in a crossover study in this setting. Twelve patients, 18 to 28 hours after cardiac surgery (coronary artery bypass graft in 9, aortic valve replacement in 2 and valved aortic conduit with reimplantation of coronary arteries in 1 patient) received controlled infusions of esmolol (mean dosage 142 +/- 100 micrograms/kg/min, range 50 to 300 micrograms/kg/min) and nitroprusside (mean dose 1.6 +/- 1.3 micrograms/kg/min, range 0.5 to 2.75 micrograms/kg/min). In this open-label study, choice of the first drug was randomized, after which patients were then crossed over to the other study drug. Therapeutic response (greater than or equal to 15% systolic blood pressure reduction) was achieved in 11 of 12 esmolol patients and 12 of 12 nitroprusside patients. Both drugs significantly lowered systolic and diastolic blood pressure, as well as left ventricular stroke work index. While the cardiac index was decreased by esmolol and increased by nitroprusside, neither drug significantly changed stroke volume index. Systemic vascular resistance, unchanged by esmolol, was decreased significantly by nitroprusside. Oxygen saturation and Pao2, unchanged with esmolol, were both significantly reduced with nitroprusside. Thus, for hypertension early after cardiac surgery, esmolol is safe, effective and rapid and, compared with nitroprusside, results in less unwanted decrease in diastolic blood pressure and oxygen saturation, but there is more decrease in heart rate and cardiac index.

Adrenal function following coronary bypass surgery.

Little is known about adrenocortical function after coronary bypass surgery in which moderate to deep hypothermia and cardiopulmonary bypass are used particularly with intraoperative steroid administration. Therefore, we performed a pilot study in which immediately preoperative and 18-hour postoperative serum cortisol levels were determined in eight patients who received 1.0 to 1.5 gm of methylprednisolone intravenously during surgery; postoperative serum cortisol (3 +/- 1 microgram%) levels were lower than preoperative levels (15 +/- 3 microgram%, p less than 0.05). To determine the possible cause of these striking findings, the effects of moderate to profound hypothermia and cardiopulmonary bypass upon adrenocortical functioning were investigated without the influence of intraoperative steroid administration. Serum cortisol and aldosterone levels and their response to adrenocorticotropic hormone (ACTH) (Cortrosyn) were determined before coronary bypass surgery and at various postoperative intervals in seven patients. Postoperative cortisol and aldosterone levels increased markedly over their preoperative values, reaching a maximum at 6 to 12 hours (cortisol 16 +/- 8 vs 63 +/- 23 micrograms%, p less than 0.05, aldosterone 15 +/- 5 vs 51 +/- 22 ng%, p less than 0.05). Adrenal response to ACTH was normal preoperatively, during rewarming from hypothermia, and 18 hours, and 7 days postoperatively. In summary, normal adrenal responsiveness occurs after coronary bypass surgery, in spite of hypothermic cardiopulmonary bypass and the effects of anesthesia, and a single dose of methylprednisolone during surgery is associated with markedly lower serum cortisol levels and prevents the usual adrenal stress response to bypass surgery for at least 18 hours postoperatively.