What determines geographical variation in rates of acceptance onto renal replacement therapy in England?

OBJECTIVE: To determine the independent effects of need and supply factors on the known geographical variation in acceptance rates onto renal replacement therapy (RRT) in England. METHODS: Data were obtained from all renal units in England on the characteristics of all cases aged 16 years and over, resident in England, who were accepted onto RRT in 1991 and 1992. Of these, 5715 (94.5%) had a valid postcode that could be matched to a census ward. Multilevel modelling using Poisson regression was used. The number of acceptances in each census ward within age bands 16-34, 35-64 and 65+ was the dependent variable. Independent effects modelled were: (1) individual factors (age, sex); (2) census ward need factors--ethnicity (expressed as the percentage of the ward population that was Asian or African-Caribbean), socio-economic deprivation--and supply factors--'access' to the nearest renal unit using crowfly and road travel time and distance, and services available to each ward expressed as number of haemodialysis stations per 100,000 catchment population of the nearest renal unit; (3) district health authority level effects. RESULTS: Age was a major determinant of acceptance, with a 7-fold higher rate in males aged over 64 years compared with younger men. Acceptance rates were lower in females, with a negative age-sex interaction in females aged over 64 years. The percentage of both Asian and African-Caribbean populations per ward was a highly significant positive determinant. Deprivation was also a significant determinant, best represented by a customised index. There was an inverse relation of acceptance with distance, especially road travel time. Other supply side variables had a significant effect though there was no independent district effect. There was some variation in the strength of these relationships by type of area (Greater London, urban and non-urban). CONCLUSIONS: Need and supply factors influence service use as expressed as acceptance onto RRT. Pressure to expand RRT services needs to be aimed at areas with large minority ethnic populations and those living far from existing units.     

The financial impact of teaching surgical residents in the operating room

BACKGROUND: There have been no published data regarding the cost of training surgical residents in the operating room. METHODS: At the University of Tennessee Medical Center-Knoxville, in addition to resident-performed teaching cases, some cases are performed without the assistance of residents by the same faculty. RESULTS: Sixty-two case categories involving 14,452 cases were compared for operative times alone. In 46 case categories (10,787 procedures), resident operative times were longer than faculty alone. In 16 case categories, resident operating times were shorter than faculty times. The net incremental operative time cost was 2,050 hours between July 1993 and March 1997. Assuming 4 years of operative training for 11 graduating chief residents, the cost per graduating resident was $47,970. CONCLUSION: Extrapolated to a national annual cost for the 1,014 general surgery residents who completed training in the 1997 academic year, the annual cost of training residents in the operating room is $53 million. This high monetary cost suggests the need for digital skills, selection criteria, the development of training curriculum and resource facilities, the pre-operating room need for suturing and stapling techniques, and perhaps the acquisition of virtual surgery training modules.     

The Organization of Projections from Subdivisions of the Auditory Cortex and Thalamus to the Auditory Sector of the Thalamic Reticular Nucleus in Galago

Anterograde and retrograde transport techniques were used to study the connexions between different subdivisions of the auditory cortex and thalamus with the thalamic reticular nucleus in the prosimian, Galago. In particular, the goal was to determine whether the primary auditory nucleus, GMv, and its cortical target, area I of the auditory cortex (A I), project to a different region of the auditory sector of the reticular nucleus from the secondary auditory nuclei, GMmc and Po and their cortical targets outside A I. The results show that the projections to and from the auditory sector are indeed segregated: injections of wheatgerm agglutinin-conjugated horseradish peroxidase into either GMmc or Po labelled cells and terminals along the medial, lateral and ventral borders of the auditory sector, forming a U-shaped pattern. Projections from area II of the auditory cortex produced almost an identical pattern of the terminal labelling in the auditory sector. In contrast, injections into GMv-labelled cells and terminals in the centre region of the auditory sector, in the 'interior' of the U-shaped region. Projections from A I were distributed to both the U-shaped border region and the central core of the auditory sector probably because A I received projections from GMmc, Po and GMv. The significance of these results depends on a comparison between the auditory and visual sectors of the reticular nucleus. Both sectors are divided into tiers or subsectors-one related to the primary relay nucleus, i.e. GLd or GMv, and the other related to the secondary relay nuclei, i.e. pulvinar nucleus, GMmc, Po, etc.     

Successful therapy of crystalcryoglobulinemia: a case report.

Successful therapy for a case of multiple myeloma with a spontaneously crystallizing cryoglobulin of the IgG2-kappa light chain variety was achieved, using both continuous-flow cell centrifugation plasmapheresis to rapidly lower the M component and combination chemotherapy with phenylalanine mustard, prednisone, procarbazine, and vincristine to control the myeloma process. This resulted in resolution of incapacitating large and small necrotic cutaneous ulcerations of the extremities. Physicochemical studies of the crystalcryoprotein demonstrated that cryoprecipitation was rapid and accompanied by the formation of needle-shaped crystals, yet was completely reversible at 37 degrees C. Cryocrit determinations varied depending upon relative centrifugal forces and temperature and did not always relate linearly to the amount of abnormal protein, thus making these alone unreliable in assessing response to therapy.     

The measurement of spatial contrast sensitivity in cases of blurred vision associated with cerebral lesions.

Thirty-five patients with known cerebral lesions complained of recently acquired blurred vision. None of them had evident oculomotor or pupillary abnormalities, and each had intact central fields and normal visual acuity by conventional standards. Examination of spatial contrast sensitivity was carried out with sinusoidal grating patterns, by determining the minimum contrast between alternate light and dark bars required to distinguish the pattern from a homogeneous field. This was done at each of several spatial frequencies which were established by varying the width of the bars and hence the coarseness of the pattern. The contrast sensitivities were plotted as "visuograms" which, by analogy to audiograms, record the sensitivities in comparison to normal standards. Of the 35 patients, most showed significant losses, amounting to greater than 50 per cent elevation of contrast thresholds. Eighteen showed high frequency losses; 11 had uniform reductions over the entire visible spatial frequency range and 6 had selective frequency losses in the intermediate frequency ranges. These defects in spatial contrast sensitivity, which were not predictable from standard acuity scores, indicate that the visual symptoms in our patients may have been caused by damage to frequency-selective neural elements in the central visual systems. The method may be used to advantage in clinical investigations as well as in physiological investigations of the functional pathways subserving central vision.     

Controlled family study of anorexia nervosa and bulimia nervosa: evidence of shared liability and transmission of partial syndromes

OBJECTIVE: Lifetime rates of full and partial anorexia nervosa and bulimia nervosa were determined in first-degree relatives of diagnostically pure proband groups and relatives of matched, never-ill comparison subjects. METHOD: Rates of each eating disorder were obtained for 1,831 relatives of 504 probands on the basis of personal structured clinical interviews and family history. Best-estimate diagnoses based on all available information were rendered without knowledge of proband status and pedigree identity. Only definite and probable diagnoses were considered. RESULTS: Whereas anorexia nervosa was rare in families of the comparison subjects, full and partial syndromes of anorexia nervosa aggregated in female relatives of both anorexic and bulimic probands. For the full syndrome of anorexia nervosa, the relative risks were 11.3 and 12.3 in female relatives of anorexic and bulimic probands, respectively. Bulimia nervosa was more common than anorexia nervosa in female relatives of comparison subjects, but it, too, aggregated in the families of ill probands; the corresponding relative risks for bulimia nervosa were 4.2 and 4.4 for female relatives of anorexic and bulimic probands, respectively. When partial syndromes of anorexia nervosa and bulimia nervosa were considered, relative risks fell by one-half in each group of ill probands. CONCLUSIONS: Both anorexia nervosa and bulimia nervosa are familial. Their cross-transmission in families suggests a common, or shared, familial diathesis. The additional observation that familial aggregation and cross-transmission extend to milder phenotypes suggests the validity of their inclusion in a continuum of familial liability.     

Liver allotransplantation after extracorporeal hepatic support with transgenic (hCD55/hCD59) porcine livers: clinical results and lack of pig-to-human transmission of the porcine endogenous retrovirus

BACKGROUND: Whole organ extracorporeal perfusion of a genetically modified humanized (transgenic) pig liver has been proposed as a technology that may sustain patients with severe liver failure while awaiting human liver transplantation. METHODS: We report on two cases of successful extracorporeal perfusion of a transgenic pig liver in patients awaiting transplantation for fulminant hepatic failure. The pig livers used were transgenic for human CD55 (decay-accelerating factor) and human CD59. These transgenic modifications are designed to reduce or eliminate the hyperacute rejection inherent in pig-to-primate xenotransplants. We also report on the results of serial surveillance testing for presence of the porcine endogenous retrovirus (PoERV) in these two patients. RESULTS: Extracorporeal perfusion in two patients was performed for 6.5 and 10 hr, respectively, followed by the successful transplantation of a human liver and resultant healthy patients (18 and 5 months later as of this writing). The porcine livers showed evidence of synthetic and secretory function (decreasing protime and bilirubin, bile production). Serial polymerase chain reaction analysis of these patients' peripheral blood mononuclear cells has failed to show presence of PoERV DNA sequences. CONCLUSIONS: The CD55/CD59 transgenic porcine liver appears capable of safely "bridging" a patient to liver transplantation. Human PoERV infection from these livers has yet to be demonstrated.     

Speed of information processing in traumatic brain injury: modality-specific factors

OBJECTIVE: To assess speed of information processing by two serial addition tests (one visual, one auditory) in individuals with moderate-to-severe traumatic brain injuries (TBIs) and in a healthy, normal control group (NC). The tasks were designed to equate and control for accuracy of performance across the TBI and NC groups, thus allowing for quantification of information processing speed. DESIGN: Performance across groups and tasks were compared using 2 x 2 repeated measure analyses of variance (ANOVAs). In addition, each individual's processing speed was used to adjust rate of stimulus presentation on a subsequent "rehabilitation" trial to determine further whether this adjustment equated accuracy of performance. SETTING: Rehabilitation hospital. PATIENTS: 22 outpatients with moderate-to-severe TBI (6 women, 16 men; mean age = 34.6 years; duration of loss of consciousness = 22.6 days) and 20 age- and education-matched healthy controls. RESULTS: Processing speed was slower in TBI subjects, relative to controls and was significantly related to measures of executive functioning for those with TBI. Relative to controls, speed of processing in the TBI group was disproportionately slower when information was presented in the auditory, relative to the visual, modality. CONCLUSIONS: Speed of information processing is a major impairment in those with TBI when unconfounded by performance accuracy. The modality-specific impairment observed in the TBI group may, in part, be due to a greater within-modality interference effect created by the auditory version of the task. By manipulating information at a pace customized for an individual through compensatory strategies and environmental modifications, information-processing performance of TBI participants can be enhanced significantly.