Basic rate ISDN workstation traffic patterns

At present, the PC class of machine equipped with a modem and connected to the public switched telephone network (PSTN) finds many applications; access to electronic mail services, access to office computers by home-workers, occasional access to a mainframe from an isolated office, etc. Two developments are coinciding which will affect this usage; PCs are being upgraded into much more sophisticated workstations, and the PSTN is to be replaced by the integrated services digital network (ISDN), a digital service offering much greater bandwidth. These developments will have a significant effect on the ways in which isolated machines are used. Some results are presented from an assessment made at University College London on the extent to which modes of usage currently prevalent on LANs might translate to the ISDN workstation. Measurements have been made of traffic on a L LAN, and extrapolations have been made to gauge the effects of interposing ISDN both on performance and on cost.     

A study of the 'lived' experience of change during a period of curriculum and organizational reform in a department of nurse education

In this paper an attempt is made to illustrate the experience of lecturers in a department of nursing preparing to implement the adult branch component of the pre-registration Higher Education Diploma in Nursing Studies. The study was conducted in a college of health in England at a time when the college was only beginning to discuss the possibility of closer links with universities. It highlights the grief responses associated with change exhibited by nursing lecturers during a period of organizational upheaval and curriculum change and maps the transition through stages of adaptation over a 2-year period. The analysis of the effects of change and the coping strategies adopted by nursing lecturers presented here is most relevant to educational managers who are charged with integrating nurse education into higher education.     

Teenage driving fatalities

BACKGROUND/PURPOSE: A recent legislative effort in New Hampshire to institute a graduated licensing system for teenagers (TA) led to an analysis of state data on fatal crashes involving TA drivers. This provides an overview of these events and suggests possible prevention strategies. METHODS: Data on fatal crashes involving TA drivers was obtained for the years 1991 through 1996 from the Fatal Accident Unit, Division of State Police, New Hampshire Department of Safety. RESULTS: From 1991 through 1996, there were 100 events resulting in 109 total deaths, of which 76 were TA. Five involved motorcycles. Four drivers struck pedestrians, and two struck children on bicycles. In one case, an object fell from a truck, crushing a car. The remaining 88 were single- or multiple-car crashes, and these were analyzed further. Two thirds of the drivers were boys. The driver breakdown by age was 15 years, 3; 16 years, 21; 17 years, 26; 18 years, 20; 19 years, 18. The TA driver was killed in 47% of the events. Nineteen percent resulted in the death of the driver of another car. In 62 events, there were passengers in the TA's car, and in 55% of these, a passenger was killed. Twenty percent of the crashes involved drugs or alcohol, and almost two thirds of these occurred between 10:00 PM and 6:00 AM. Seat belts were not used by at least 72% of those injured fatally. In 59%, known traffic violations, usually speeding, contributed. More detailed data were available for 1995 through 1996, during which there were 30 crashes resulting in 33 deaths. Speed limit did not correlate with number of crashes. One-car crashes outnumbered multiple-car, 57% to 43%. Ninety percent occurred on single-lane roads. Most significantly, 63% of the drivers had been licensed less than 1 year and 47% less than 6 months. In this latter group, drugs and alcohol played no role, and none occurred between 11:00 PM and 6:00 AM. CONCLUSIONS: Two at-risk groups exist. The first is inexperienced sober TA drivers on single-lane roads during conventional hours. As experience increases, the second group appears: TA who have been drinking and are out late at night. Prevention strategies must take into account these two groups.     

Extracellular levels of dopamine and its metabolite 3,4-dihydroxy-phenylacetic acid measured by microdialysis in the corpus striatum of conscious AS/AGU mutant rats

The AS/AGU rat is a mutant derived from the Albino Swiss (AS) strain. It is characterized by an ungainly, staggering gait, hind limb rigidity, whole body tremor and, in older animals, difficulty in initiating movement. As and AS/AGU males aged three, six and nine months (n=6 per group) were used to estimate the levels of dopamine and its metabolites in the extracellular fluid of the caudate-putamen. The results indicate a profound loss of dopamine in the extracellular fluid at all age points examined, together with an increase in the concentration of the metabolite 3,4-dihydroxyphenylacetic acid. It is suggested that these changes reflect a defect of dopaminergic neuron function which may underlie the motor disorder seen in these animals.     

Syntaxin 4, VAMP2, and/or VAMP3/cellubrevin are functional target membrane and vesicle SNAP receptors for insulin-stimulated GLUT4 translocation in adipocytes

Introduction of the cytoplasmic domain of syntaxin 4, using either recombinant vaccinia virus or single-cell microinjection, resulted in an inhibition of insulin-stimulated GLUT4 but not GLUT1 translocation to the plasma membrane. This was specific for syntaxin 4, since neither the expression of syntaxin 3 nor the expression of a syntaxin 4 mutant in which the vesicle-associated membrane protein (VAMP) binding site was deleted had any significant effect. Consistent with the requirement for a functional VAMP binding site, expression of the cytoplasmic domains of VAMP2 or VAMP3/cellubrevin also resulted in an inhibition of insulin-stimulated GLUT4 translocation. In addition, immunoprecipitation of the expressed syntaxin 4 cytoplasmic domain resulted in an insulin-stimulated increase in the coimmunoprecipitation of GLUT4-containing vesicles. Together, these data demonstrate that syntaxin 4, VAMP2, and/or VAMP3/cellubrevin can function as target membrane and vesicle SNAP receptors, respectively, for insulin-responsive GLUT4 translocation to the plasma membrane.     

Technetium-99m-MAG3 renal studies in spinal cord injury patients: normal range, reproducibility, and change as a function of duration and level of injury

The normal range, reproducibility, and change as a function of duration and level of injury for Tc-99m-MAG3 renal studies were quantitated in spinal cord injury (SCI) patients. METHODS: Five SCI patients without evidence of renal disease in each of four groups: less than 2 months, 2-12 months, 1-2 years, and greater than 2 years from time of injury, were each studied twice. There were at least two patients with paraplegia and two with tetraplegia in each group. Renal clearance (camera based method), percent function in each kidney, time of peak renal parenchymal activity, and half time of parenchymal activity following the peak were evaluated. The peak and half times were determined with regions of interest (ROIs) over the entire kidney and over just the cortex. All results were compared to normal ranges previously established in normal subjects of the same age range using the same methodology. RESULTS: Renal clearance in the less than 2 month SCI patients was not significantly different from normal subjects in either paraplegic or in tetraplegic individuals. However, clearance in tetraplegics was increased by 28.5% at 2-12 month, increased by 50.6% at 1-2 years, and decreased by 25.9% at greater than 2 years compared to normal subjects (all P < 0.02). Clearance in those with paraplegia showed a similar, but less marked, trend (P = NS). The time of peak parenchymal activity when measured with cortical ROIs did not vary among patient groups or level of injury, but was increased compared to normal subjects (P < 0.05). The percent function in each kidney and half time following the peak were symmetrical, did not differ among patient groups or with level of injury, and did not differ from normal subjects. The parenchymal peak time was significantly shorter with cortical rather than renal ROIs in all patient groups (P < 0.05). In serial studies in the same patient the percent standard deviation in total renal clearance was less than between single studies in different patients, but the decrease was significant for only the right kidney (P < 0.03), and the decrease was not as great as in normal subjects. In addition, the percent standard deviation for percent function in each kidney was significantly less than the percent standard deviations in single studies (P < 0.02). There were no significant differences between intra- and interpatient studies for any other parameter. CONCLUSION: We conclude that: (1) renal clearance measured with Tc-99m-MAG3 in tetraplegic patients increases significantly during the first 2 years following injury and decreases significantly thereafter; there is a similar, but much less marked, trend in paraplegics, (2) parenchymal peak times with cortical ROIs occur later for SCI patients than for normal subjects, and (3) there is more intrapatient variation in total renal clearance and percent renal clearance on a side in SCI patients than in normal subjects suggesting that it may be harder to study SCI patients reproducibly. These findings should be taken into account when performing and interpreting Tc-99m-MAG3 renal studies in SCI patients.     

Expression of colonic antigens by goblet and columnar epithelial cells in ileal pouch mucosa: their association with inflammatory change and faecal stasis

AIMS: To investigate colonic metaplasia of goblet and columnar epithelial cells in ileal pouch mucosa; to correlate this with the degree of morphological and inflammatory change; and to assess whether such changes are related to the presence of faecal stasis. METHODS: Biopsy specimens of ileal pouch mucosa were taken from 31 patients (30 with ulcerative colitis, one with familial adenomatous polyposis) either before (eight patients) or after (23 patients) ileostomy closure. A simple morphological technique was used to assess changes in villous height. Inflammatory change was estimated using an established scoring system for pouchitis, and acquisition of colonic antigens was determined by immunohistochemistry using three monoclonal antibodies which recognise components of the two major epithelial cell types in the colorectum. The degree of staining with the monoclonal antibodies was graded and the grades correlated with an index of villous atrophy and with the inflammatory scores. RESULTS: Five of eight (63%) pre-closure and 15 of 23 (65%) post-closure biopsy specimens showed increased staining with an antibody against components of columnar epithelial cells. One of eight (12%) pre-closure and 15 of 23 (65%) post-closure biopsy specimens stained with an antibody for colonic mucin. Although both types of staining showed a positive correlation with the pouchitis score, they also occurred in the absence of inflammation. CONCLUSIONS: Both goblet and columnar cells acquire colonic characteristics which are incomplete, but may represent a true adaptive response as they can develop in the absence of inflammation. As the change in goblet cells occurs after ileostomy closure, faecal stasis is likely to be a major contributory factor. Changes in columnar cells may occur before ileostomy closure in the absence of faecal stasis.