Visual perceptions of head-fixed and trunk-fixed anterior/posterior axes

The purpose of the present experiment was to determine the preferred visual straight ahead or anterior/posterior (a/p) axis at the perceptual level. The ability of 12 neurologically normal, young adult subjects to position a rod parallel to the head and trunk a/p axes while viewing eccentrically located visual targets were studied under six conditions: 1. fixed — subjects stood erect with the head aligned to the trunk and viewed a central target while visually aligning a hand-held rod to the head and trunk a/p axis. 2. eyes — subjects moved only their eyes to view eccentric targets and aligned the rod to the head and trunk a/p axis. 3. head-trunk — subjects viewed the eccentric targets by rotating the head about a vertical axis and aligned the rod to the trunk a/p axis. 4. head-head — subjects viewed the targets as in 3 and positioned the rod parallel to the head a/p axis. 5. trunk-head — subjects viewed the targets by rotating the trunk and head as a unit about the vertical axis and aligned the rod parallel to the head a/p axis (note that the head and trunk a/p axes were misaligned by the experimenter prior to target viewing). 6. trunk-trunk — subjects viewed targets as in 5 and positioned the rod parallel to the trunk a/p axis. Subjects performed 25–35 consecutive trials within each condition. Perceptual errors were similar for aligning the rod to the trunk and head a/p axes; however, moving the trunk produced much larger constant and variable perceptual errors than moving the head. In a second experiment, four subjects controlled the position of a lighted rod held by a robot arm in complete darkness. They were instructed to align the rod to either the head or trunk a/p axis under conditions similar to the fixed, head-trunk, and head-head tasks described above. Perceptual errors were much larger when aligning the rod to the head a/p axis than to trunk a/p axis when the head was moved. This shows that the trunk a/p axis is clearly preferred at the perceptual level when visual background cues are not present.These data strongly suggest that the visual coordinate system uses a trunk-fixed a/p axis to define the subjective straight-ahead direction and right/left position of a target. Implications of these findings for sensorimotor transformations in control of upper limb movements to visual targets are discussed.     

Malignant lymphoma, small lymphocytic type: a clinicopathologic study of 84 cases with suggested criteria for intermediate lymphocytic lymphoma.

Clinical and histopathologic findings were reviewed in 84 cases of malignant lymphoma of the small (well differentiated) lymphocytic type. The slides were studied without clinical information, and the following morphologic features were evaluated: pattern of growth, number of large lymphocytes, mitotic rate, degree of capsular involvement, presence of plasma cells and/or plasmacytoid lymphocytes, and presence of residual germinal centers. Subsequently, clinical information was obtained. The minimum follow-up period on living patients was 5 years. The patients were divided into 3 clinical categories: 1) monoclonal gammopathy (MG)-11 cases, 2) chronic lymphocytic leukemia (CLL) without MG-56 cases, and 3) those without MG or CLL at the time of lymph node biopsy-17 cases. The criterion for CLL was an initial absolute lymphocyte count less than 4000/mm3. Four of the patients with MG also had CLL, and 6 of those in the third group later developed CLL, from 1 to 61 months after lymph node biopsy. Generalized lymphadenopathy was the usual presentation in all 3 groups, and bone marrow examination was positive in all but 1 of the 49 cases, representing all 3 groups, in which it was performed. Median survival for the 84 patients was 51 months. The only clinical parameters which showed a significant association with poorer survival were age above 60 and anemia (Hb. conc. less than 11.0). There was no significant relationship between morphologic characteristics and clinical categories other than the association of plasmacytoid cells with MG in 6 cases. A mitotic rate of 30 or more mitoses per 20 high power fields (HPF), found in 5 cases with at least 1 in each clinical category, showed a highly significant association with decreased survival (p = .01). Variations in mitotic rate between 0 and 29 mitoses per 20 HPF and other morphologic parameters did not show a significant relationship with prognosis. It was concluded that malignant lymphoma of the small lymphocytic type is a definite clinicopathologic entity which may or may not exhibit MG or CLL, and it is proposed that the term "intermediate lymphocytic lymphoma" be applied only to those cases showing histopathologic characteristics of small lymphocytic lymphoma and a mitotic rate of 30 or more mitoses per 20 HPF.     

A six year longitudinal study of the occupational consequences of drinking over "safe limits" of alcohol.

Although much research has focused on the psychological, social, and economic consequences of heavy problem drinking, there has been far less attention paid to the consequences of "moderate" drinking. This study used a unique opportunity to carry out a six year follow up of a cohort of male and female white collar workers in whom there was baseline information on alcohol consumption and access to details on sickness absence, labour turnover, and promotion. It has provided evidence that even moderate alcohol consumption in the working population is associated with social costs for the employer and the employee, including substantial sickness absence, and lack of promotion in men, although the increase in labour turnover was not statistically significant. The longitudinal examination of consumption in this study suggests that early intervention in a drinking career may reduce alcohol consumption and consequently avoid years of morbidity and sickness absence, as well as having a favourable influence on performance and labour turnover.     

The no-reflow phenomenon is a post-mortem artifact

Summary Post-ischemic reperfusion impairment, (no-reflow phenomenon), was studied in rats subjected to 8–30 minutes of global brain ischemia. During ischemia, rapid and complete loss of cerebral blood flow, EEG and³¹P-high energy phosphates (ATP/PCr) was observed.Brain intravascular perfusion defects were examined by injecting carbon blackintravenously in a group of rats with stable cardiopulmonary function and in another group subjected to rapid thoracotomy andintraarterial infusion of the carbon marker. Results indicate that global brain ischemic or non-ischemic control rats givenintraarterial carbon black after thoracotomy had varying degrees of vessel filling defects in brain resulting in pale tissue areas suggestive of impaired perfusion (no-reflow). All rats given carbon blackintravenously whether global brain ischemic or not, showed normal cerebrovascular filling of the carbon black and absence of pale tissue areas. In addition, post-ischemic cerebral reperfusion following 8–30 minutes global brain ischemia can reverse neuroelectric, energy metabolite and cerebral blood flow loss in rats whose cardiopulmonary function is not compromised.These findings indicate that the no-reflow phenomenon is an agonal or post-mortem artifact observed in the presence of cardiopulmonary failure.     

A six year longitudinal study of the occupational consequences of drinking over "safe limits" of alcohol.

Although much research has focused on the psychological, social, and economic consequences of heavy problem drinking, there has been far less attention paid to the consequences of "moderate" drinking. This study used a unique opportunity to carry out a six year follow up of a cohort of male and female white collar workers in whom there was baseline information on alcohol consumption and access to details on sickness absence, labour turnover, and promotion. It has provided evidence that even moderate alcohol consumption in the working population is associated with social costs for the employer and the employee, including substantial sickness absence, and lack of promotion in men, although the increase in labour turnover was not statistically significant. The longitudinal examination of consumption in this study suggests that early intervention in a drinking career may reduce alcohol consumption and consequently avoid years of morbidity and sickness absence, as well as having a favourable influence on performance and labour turnover.     

Effective therapy for Burkitt's lymphoma: High-dose cyclophosphamide + high-dose methotrexate with coordinated intrathecal therapy

Summary A new treatment for Burkitt's lymphoma (BL) has been devised with coordinated intrathecal (IT) methotrexate (MTX) + high-dose intravenous (IV) MTX with citrovorum factor (CF) rescue and high-dose Cytoxan (CYT). Six patients have been entered on the study. Five patients continue in complete remission at 13+–31+ months (median, 29+ months). One died of septicemia during myelosuppression. Only minor toxicity was seen in four patients. Two patients had severe metabolic disturbances following initial CYT therapy; one of these patients also had reversible, moderately severe hepatorenal MTX toxicity. No neurotoxicity was observed. Results of therapy are impressive in this limited patient group, four of whom were poor-prognosis (Stage C or D) and two of whom were good-prognosis patients (Stage B or AR). The potential for severe toxicity is great; adherence to the criteria for drug administration and close surveillance of the patient in the post-treatment period are mandatory.Plasma and cerebrospinal fluid (CSF) MTX pharmacokinetics were studied in three patients. CSF MTS levels exceeded 10^-6 M with coordinated IT-IV MTX (150 mg/kg body wt.) With MTX infusions at the 200 mg/kg level, therapeutic concentrations were maintained in the CSF for approximately 60 h. Plasma MTX concentrations exceeded 10^-6 M at all infusion dose levels, the duration of the therapeutic concentration increasing with the dose level. Priming IT MTX followed in 24 h by IV MTX, 200 mg/kg assured therapeutic concentrations in plasma and CSF of sufficient duration to cover two generation times of the BL cell.     

In vivo degradation of tungsten embolisation coils

It has been suggested that tungsten embolisation coils in intracranial aneurysms may dissolve in situ. These coils are also used, in much larger quantities, for the occlusion of larger vessels outside the cranium. This study was performed to investigate whether tungsten embolisation coils may become degraded in vivo and to examine whether this is radiographically evident on medium-term follow-up. 10 patients who had undergone aortic stent-graft repair of an abdominal aortic aneurysm (8 male and 2 female, mean age 69.7 years) and 10 age- and sex-matched controls were studied. The study group had also received an average of 64 cm of tungsten coil either to prevent or to treat an endoleak. Whole blood, serum and urine tungsten levels were assayed. Immediate post-operative and follow-up abdominal radiographs were reviewed by two consultant vascular radiologists to detect visible changes in the coils. Whole blood, serum and urine levels of tungsten were highly and significantly elevated (p < 0.001) in the study group compared with the controls. No radiographic changes in the coils were seen at an average of 16.7 months. In conclusion, tungsten embolisation coils dissolve in humans but radiographic changes are not apparent on medium-term follow-up. The clinical significance of these findings is uncertain but long-term follow-up is needed.     

Multimodality treatment of nongalenic arteriovenous malformations in pediatric patients

OBJECTIVE: Previously reported series of arteriovenous malformations (AVMs) in pediatric patients have primarily used a single-modality treatment approach of either surgery, radiosurgery, or embolization, with significant treatment-related morbidity and mortality. At our institution, we have used a combined multidisciplinary team approach of all three treatment modalities, alone or in combination, to minimize complications and to maximize efficacy in the management of these lesions. METHODS: We retrospectively reviewed 40 consecutive pediatric patients with AVMs seen at our institution from 1991 to 1999. A multidisciplinary team planned the treatment for each AVM. The treatment modality consisted of the following approaches: surgery alone in 14 patients, a combination of endovascular embolization and surgery in 6 patients, radiosurgery alone in 11 patients, a combination of endovascular embolization and radiosurgery in 2 patients, and a combination of radiosurgery and surgery in 2 patients. Four patients are receiving ongoing multistaged treatment for reduction of the nidus size for eventual surgical resection or radiosurgical obliteration of large, complex lesions. In one patient, no treatment was recommended. RESULTS: The clinical outcomes for the overall series were 95.0% excellent or good (Glasgow Outcome Scale score 5 or 4), 2.5% fair (Glasgow Outcome Scale score 3), and 2.5% dead. Radiographic efficacy in the patients who have completed treatment was 92.9% complete obliteration of their AVMs and 7.1% incomplete obliteration. Of the 10 patients who had seizures, 9 are seizure-free. CONCLUSION: A combined multimodality approach of surgery, radiosurgery, and embolization in managing AVMs in pediatric patients can improve outcomes and minimize morbidity and mortality.