Characterization of MR Imaging-Visible Perivascular Spaces in the White Matter of Healthy Adolescents at 3T.

BACKGROUND AND PURPOSE: Perivascular spaces play a role in cerebral waste removal and neuroinflammation. Our aim was to provide data regarding the burden of MR imaging-visible perivascular spaces in white matter in healthy adolescents using an automated segmentation method and to establish relationships between common demographic characteristics and perivascular space burden. MATERIALS AND METHODS: One hundred eighteen 12- to 21-year-old subjects underwent T1- and T2-weighted 3T MR imaging as part of the National Consortium on Alcohol and Neurodevelopment in Adolescence. Perivascular spaces were identified in WM on T2-weighted imaging using a local heterogeneity approach coupled with morphologic constraints, and their spatial distribution and geometric characteristics were assessed. RESULTS: MR imaging-visible perivascular spaces were identified in all subjects (range, 16-287). Males had a significantly higher number of perivascular spaces than females: males, mean, 98.4 ± 50.5, versus females, 70.7 ± 36.1, (P < .01). Perivascular space burden was bilaterally symmetric (r > 0.4, P < .01), and perivascular spaces were more common in the frontal and parietal lobes than in the temporal and occipital lobes (P < .01). Age and pubertal status were not significantly associated with perivascular space burden. CONCLUSIONS: Despite a wide range of burden, perivascular spaces are present in all healthy adolescents. Perivascular space burden is higher in adolescent males than in females, regardless of age and pubertal status. In this population, perivascular spaces are highly symmetric. Although widely reported as a feature of the aging brain, awareness of the presence of perivascular spaces in a cohort of healthy adolescents provides the foundation for further research regarding the role of these structural variants in health and disease.

DNATwist: a Web-based tool for teaching middle and high school students about pharmacogenomics.

DNATwist is a Web-based learning tool (available at http://www.dnatwist.org) that explains pharmacogenomics concepts to middle- and high-school students. Its features include (i) a focus on drug responses of interest to teenagers (e.g., alcohol intolerance), (ii) reusable graphical interfaces that reduce extension costs, and (iii) explanations of molecular and cellular drug responses. In testing, students found the tool and topic understandable and engaging. The tool is being modified for use at the Tech Museum of Innovation in California.

Radiotherapy for head and neck cancer.

The length and quality of head and neck cancer survivorship continues to improve. Radiotherapy has been central to this process through advances in treatment technology, fractionation schemas, radiosensitizing chemotherapy, and surgical technique. The future of head and neck radiotherapy looks brighter still with progress in radiosensitizing biologic therapy, molecular characterization, functional imaging, and rehabilitative strategies fast approaching. Head and neck cancer, a disease once fraught with nihilism and failure, is evolving into a major success story of multidisciplinary solid tumor management. Continued dedication and work on the part of provider and patient alike will be required to make this promise a reality.

The use of trimodality therapy for the treatment of operable esophageal carcinoma in the veteran population: patient survival and outcome analysis.

BACKGROUND: In an effort to improve the cure rates associated with surgical therapy, neoadjuvant chemoradiotherapy is being used with increasing frequency before resection (trimodality therapy). A variety of clinical trials have reviewed this approach, but only one study to the authors' knowledge has shown a survival benefit for trimodality therapy. The extent to which trimodality therapy has gained acceptance in general practice is not clear. The objective of the current study was to determine the extent to which both surgery and trimodality therapy are used for the management of esophageal carcinoma within a large, national health care system and to determine the outcome of patients treated with these treatment approaches. METHODS: The current study was a retrospective cohort study. The study population was comprised of all veterans who underwent either surgery alone or trimodality therapy for operable esophageal carcinoma between the fiscal years of 1993 and 1997. Data were obtained from the Veterans Administration Patient Treatment File, Outpatient Clinic File, and the Beneficiary Identification Record Locator System. The main outcome measures were perioperative mortality and patient survival. RESULTS: During the study period, 695 patients underwent either surgery alone or trimodality therapy for esophageal carcinoma. Five hundred thirty-four (77%) patients were treated with surgery only. One hundred sixty-one (23%) patients underwent surgery after induction chemoradiotherapy (trimodality therapy). Patients selected for trimodality therapy were younger (mean age, 60.8 years vs. 65.6 years), had fewer comorbidities, and were more likely to have a midesophageal tumor. The median survival for all patients was 15.2 months. The type of treatment had no apparent effect on survival. Favorable prognostic factors included younger age, a distal esophageal tumor, and the absence of metastases. The overall perioperative mortality was 13.7 %. The use of trimodality therapy did not increase perioperative mortality. CONCLUSIONS: Trimodality therapy is commonly used within the VA system. The nonrandomized nature of this study does not allow comparison of trimodality therapy to surgery alone, but the overall survival was limited for all patients. The predictors of survival are related to the biology of the disease, and they include patient age, tumor location, and stage at diagnosis.

Fast neutron radiotherapy for soft tissue and cartilaginous sarcomas at high risk for local recurrence.

PURPOSE: The practice policy at the University of Washington has been to employ fast neutron radiotherapy for soft tissue sarcoma lesions with prognostic features predictive for poor local control. These include gross residual disease/inoperable disease, recurrent disease, and contaminated surgical margins. Cartilaginous sarcomas have also been included in this high-risk group. This report updates and expands our previously described experience with this approach. METHODS AND MATERIALS: Eighty-nine soft tissue sarcoma lesions in 72 patients were treated with neutron radiotherapy in our department between 1984 and 1996. Six patients, each with solitary lesions, were excluded from analysis due to lack of follow-up. Seventy-three percent were treated with fast neutron radiation alone, the rest with a combination of neutrons and photons. Median neutron dose was 18.3 nGy (range 4.8-22). Forty-two patients with solitary lesions were treated with curative intent. Thirty-one patients (including 7 previously treated with neutrons) with 41 lesions were treated with the goal of local palliation. Tumors were predominantly located in the extremity and torso. Thirty of 35 (85%) of curative group patients treated postoperatively had close or positive surgical margins. Thirty-four (82%) lesions treated for palliation were unresectable. Thirty-five patients (53%) were treated at the time of recurrence. Median tumor size at initial presentation was 8.0 cm (range 0.6-29), median treated gross disease size was 5.0 cm (range 1-22), and 46/69 evaluable lesions (67%) were judged to be of intermediate to high histologic grade. Fourteen patients (21%) had chondrosarcomas. RESULTS: Median follow-up was 6 months (range 2-47) and 38 months (range 2-175) for the palliative and curative groups, respectively. Kaplan-Meier estimates were obtained for probability of local relapse-free survival (68%), distant disease-free survival (59%), cause-specific survival (68%), and overall survival (66%) at 4 years for the curatively treated group. For the palliatively treated group, estimated local relapse-free survival at 1 year was 62%. Log-rank analysis of the curative group revealed recurrent disease to be the only risk factor predictive for significantly worse local and distant disease-free survival. Intermediate-/high-grade histology was predictive for inferior overall survival. Effective clinical response was documented for 21/27 (78%) lesions treated palliatively. Ten patients (15%) experienced serious chronic radiation-related complications. All of these patients had clinical situations requiring delivery of high neutron doses and/or large radiotherapy fields. CONCLUSION: Fast neutron radiotherapy is locally effective for soft tissue and cartilaginous sarcomas having well-recognized high-risk features. Results in the palliative setting appear to be particularly encouraging, with neutrons frequently providing significant symptomatic response for gross disease, with minimal serious chronic sequelae. Fast neutron radiotherapy should be considered in patients at high risk for local recurrence in both the curative and palliative settings.

Catatonia in a psychiatric intensive care facility: incidence and response to benzodiazepines.

This study was performed to establish the incidence of catatonia in a psychiatric intensive care unit, to test the Bush-Francis Catatonia Screening Instrument (BFCSI) and to assess the response of catatonic signs to benzodiazepines. During a 12-month period all patients admitted to a psychiatric intensive care unit were screened for catatonic signs using the BFCSI. Patients with catatonia were further assessed with the Bush-Francis Catatonia Rating Scale (BFCRS), the Modified Rogers Scale (MRS), and scales for associated psychotic and parkinsonian symptoms. They were treated with oral lorazepam or parenteral clonazepam and their responses evaluated daily. Neuroleptics were stopped for at least 3 days. Twenty four patients met the DSM IV criteria for catatonia, giving an incidence of 15% with a significantly higher proportion of non-Europeans. The most common associated diagnosis was schizophrenia (54%). Twenty two patients completed the benzodiazepine trial. All showed significant responses after 3 days of treatment. Sixteen (16/22, 73%) had full remission within 6 days, most within 2 to 4 days. Partial responders (n = 6) all had schizophrenia and were more likely to have longer pre-trial catatonic episodes. We find the BFCSI a simple and reliable tool to screen for catatonia, and our data attest to the efficacy of benzodiazepines in the treatment of catatonia.

Multiple spontaneous small bowel anastomosis in premature infants with multisegmental necrotizing enterocolitis.

BACKGROUND/PURPOSE: Fulminant necrotizing enterocolitis (NEC) may result in extensive bowel necrosis. Resection of involved segments may result in short bowel syndrome. Multiple stomas result in complications and further loss of intestinal length with closure. METHODS: Two patients with extensive multisegmental NEC were treated with an intraluminal stent without anastomosis. All necrotic intestine was resected and the remaining viable intestine was lined up over a feeding tube without anastomosis of the intestinal segments. One patient had a diverting jejunostomy and mucous fistula with the tube used to orient the defunctionalized intervening intestinal segments. The second patient had the bowel left in continuity with the tube brought into the jejunem proximal to the first area of resection and distally brought out through the tip of the appendix. Both tubes were brought through the abdominal wall and secured in a loop. RESULTS: Contrast study findings showed that the intestinal segments had auto-anastomosed. In the first case the tube was left in place and intestinal continuity was restored. The patient is now 4 years old and takes full enteral feeds. The latter patient had the enterostomy tube removed at the time of the contrast study, but only tolerated partial feedings and died at 1 year of total parenteral nutrition-related liver failure. CONCLUSION: The technique eliminates nonviable bowel, maximizes length, avoids multiple stomas, and may help avoid reoperation.

Radiation myelitis following allogeneic stem cell transplantation and consolidation radiotherapy for non-Hodgkin's lymphoma.

Myelitis is a rare but well documented complication of therapeutic radiation exposure to the spinal cord and is characterized by delayed development of paresthesias, sensory changes and, in severe cases, progressive paresis and paralysis. Although accepted radiation tolerance limits for the spinal cord have successfully limited the incidence of this problem (45-50 Gy, in daily 1.8-2 Gy fractions), aggressive systemic therapy may render patients more susceptible to radiation-related neurotoxicity. We describe the case of a 38-year-old man with refractory non-Hodgkin's lymphoma who underwent matched sibling peripheral blood stem cell transplant following a conditioning regimen of cyclophosphamide (60 mg/kg x 2) and total body irradiation (120 cGy x 11). This was followed by delivery of 30.6 Gy involved-field radiation at 1.8 Gy/day to the mediastinum and left supraclavicular fossa for bulky residual tumor. Although maximum cumulative radiation dose to the spinal cord was less than 45 Gy, the patient subsequently developed progressive lower extremity weakness and MRI abnormalities of the spinal cord limited to the radiation field. This represents the second report in the literature of this unexpected complication, prompting a need to re-examine current guidelines for radiotherapy in the context of high-dose systemic treatment.

Tool use and the effect of action on the imagination.

Three studies examined the claim that hand movements can facilitate imagery for object rotations but that this facilitation depends on people's model of the situation. In Experiment 1, physically turning a block without vision reduced mental rotation times compared with imagining the same rotation without bodily movement. In Experiment 2, pulling a string from a spool facilitated participants' mental rotation of an object sitting on the spool. In Experiment 3, depending on participants' model of the spool, the exact same pulling movement facilitated or interfered with the exact same imagery transformation. Results of Experiments 2 and 3 indicate that the geometric characteristics of an action do not specify the trajectory of an imagery transformation. Instead, they point to people's ability to model the tools that mediate between motor activity and its environmental consequences and to transfer tool knowledge to a new situation.

Physical imagery: kinematic versus dynamic models.

Physical imagery occurs when people imagine one object causing a change to a second object. To make inferences through physical imagery, people must represent information that coordinates the interactions among the imagined objects. The current research contrasts two proposals for how this coordinating information is realized in physical imagery. In the traditional kinematic formulation, imagery transformations are coordinated by geometric information in analog spatial representations. In the dynamic formulation, transformations may also be regulated by analog representations of force and resistance. Four experiments support the dynamic formulation. They show, for example, that without making changes to the spatial properties of a problem, dynamic perceptual information (e.g., torque) and beliefs about physical properties (e. g., viscosity) affect the inferences that people draw through imagery. The studies suggest that physical imagery is not so much an analog of visual perception as it is an analog of physical action. A simple model that represents force as a rate helps explain why inferences can emerge through imagined actions even though people may not know the answer explicitly. It also explains how and when perception, beliefs, and learning can influence physical imagery.

Eighteen years' experience with neonatal Hirschsprung's disease treated by endorectal pull-through without colostomy.

METHODS: In the past 18 years, the authors have treated 84 patients with Hirschsprung's disease. Of these, 43 patients were under 1 month of age and underwent endorectal pull-through without colostomy. Some have undergone follow-up for as long as 18 years. RESULTS: Thirty-four of these 43 (79%) newborn patients were available for follow-up. Twenty-two were totally continent. The remaining 12 have normal sphincter tone. Of the 41 patients above 1 month of age, 34 (83%) were available for follow-up. Some have undergone follow-up for as long as 18 years. CONCLUSION: Twenty-two of this latter group (79%) have normal bowel control.

Variation in the management of pediatric diabetic ketoacidosis by specialty training.

OBJECTIVE: To compare management strategies for pediatric diabetic ketoacidosis (DKA) among physicians with different specialty training. METHODS: We conducted a mail survey of 1000 randomly selected physicians, including 200 pediatric endocrinologists, 200 general emergency physicians, 200 pediatric emergency physicians, 200 pediatric intensivists, and 200 pediatric chief residents. We posed questions regarding a hypothetical 10-year-old patient with new onset of diabetes mellitus who is approximately 10% dehydrated but alert, with venous pH of 7.1 and serum glucose concentration of 34.7 mmol/L (625 mg/dL). Questions involved the rate of rehydration, content of intravenous fluids, insulin therapy, potassium replacement, use of sodium bicarbonate, and adjustments in therapy for decreasing serum glucose concentration. We compared responses of physicians in each specialty and used multiple regression analysis to adjust for potential confounding variables, including number of years in practice, number of children with DKA seen per month, and practice setting. RESULTS: Five hundred eighty-one physicians (58.1%) completed the survey, with responses demonstrating significant, consistent differences between specialties. Extremes of responses included the following: (1) 59% of endocrinologists vs 11% of general emergency physicians would give an initial fluid bolus of less than 20 mL/kg (odds ratio [OR], 11.7; 95% confidence interval [CI], 5.0-27.7) (P < .001); (2) 83.5% of general emergency physicians vs 42.5% of pediatric intensivists would administer an initial insulin bolus (OR, 4.1; 95% CI, 2.0-8.7) (P < .001); (3) 58.2% of pediatric intensivists vs 9% of general emergency physicians would replace fluids over a period of greater than 24 hours (OR, 14.1; 95% CI, 5.5-37.5) (P < .001); and (4) 54.3% of general emergency physicians vs 7.3% of pediatric intensivists would use potassium chloride alone for potassium replacement (OR, 10.8; 95% CI, 5.0-23.8) (P < .001). All of these differences persisted after adjusting for the potential confounding variables. CONCLUSIONS: Substantial differences exist in the management of pediatric DKA among physicians of different specialties, presumably due to differences in specialty training. These differences obscure our ability to evaluate the treatment of DKA and highlight the necessity for further studies comparing the outcomes of different treatment strategies.

Reasoning about the referent of a picture versus reasoning about the picture as the referent: an effect of visual realism.

Research on picture perception and picture-based problem solving has generally considered the information that enables one to "see" and think about a picture's subject matter. However, people often reason about a picture or representation as the referent itself. The question addressed here is whether pictorial features themselves help determine when one reasons about the referent of an image, as with an engrossing movie, and when one reasons about the image in its own right, as with abstract art. Two experiments tested the hypothesis that pictures with relatively high fidelity to their referents lead people to think about those referents, whereas pictures with relatively low fidelity lead people to think about the picture as a referent. Subjects determined whether marks on the bottom and top boards of an open hinge would meet if the hinge were closed. Accuracy and latency results indicated that subjects who saw realistic displays simulated the physical behavior of the hinge through analog imagery. In contrast, subjects who saw schematic displays tended to reason about static features of the display such as line lengths and angles. The results demonstrate that researchers must be cautious when generalizing from reasoning about diagrammatic materials to reasoning about the referents themselves.

Dual infection of chickens with pox and infectious laryngotracheitis (ILT) confirmed with specific pox and ILT DNA dot-blot hybridization assays.

Dual infection with fowl pox (FP) and infectious laryngotracheitis (ILT) was diagnosed as the cause of acute mortality in a flock of three age groups of Hy-Line leghorn layers. The affected chickens had not been previously vaccinated against either FP or ILT. The diagnosis was confirmed by virus isolation, histopathology, and the use of specific pox and ILT genomic DNA probes in a dot-blot hybridization assay. FP and ILT vaccinations were recommended to control mortality. The use of FP- and ILT-specific DNA dot-blot hybridization may be used as a routine diagnostic tool to differentiate between the two diseases, especially in atypical cases of either infection or to confirm the existence of the two diseases as a mixed infection in a flock of chickens.

Accurate radiographic evaluation of mandibular fractures.

Proper radiographic evaluation is essential to confirm the presence and location of a mandibular fracture. The panoramic view of the mandible is considered to be a very accurate technique and has been heavily relied on by many clinicians as the initial or sole means of diagnosing mandibular fractures. Three cases of mandibular fractures are presented in which a panoramic view failed to demonstrate fractures of the mandible that were obvious on plain film radiographs. Diagnosis and treatment planning should not be based on the information obtained from a single roentgenogram such as a panoramic view. The combination of the mandibular series with the panoramic view provides increased diagnostic information that should enable accurate diagnosis of fractures in all areas of the mandible.

A case of life-threatening gastrointestinal hemorrhage in an infant with AIDS.

This is the first reported case of an infant with acquired immune deficiency syndrome (AIDS) and cytomegalovirus (CMV) infection that presented with massive life-threatening lower intestinal hemorrhage. Arteriography was useful in localizing a bleeding source prior to operation.

Idiopathic infant pyoceles.

Three infants presented with acute scrotal swelling, erythema, and a tender irreducible firm mass within the scrotum. All patients were operated upon with the preoperative diagnosis of testicular torsion. At operation, grossly purulent fluid was found in a hydrocele sac. In all the cases, the testes were normal and no source of the scrotal infection was identified. A variety of bacterial organisms were cultured and responded readily to antibiotics. Follow-up has documented survival of the testes without apparent atrophy. "Idiopathic" infant pyocele is rarely described and consequently, not included in the differential diagnosis of patients with acute surgical conditions of the inguinoscrotal region.