Starring roles for astroglia in barrier pathologies of gut and brain

The gastrointestinal tract is a highly innervated organ and enteric neuropathy is emerging as a central feature of a wide range of gut diseases. Although most considerations of the enteric nervous system have focused on neuronal dysfunction, a large population of astrocyte-like glia populates gut muscle layers and the intestinal mucosa, and mounting new evidence points toward enteric glia as active participants in gut pathology. Similarly, in the central nervous system increasing evidence suggests that dysfunctions of astrocytes play central roles in disease mechanisms. On the basis of the premise that gut-brain disease paradigms may exist, we explore the possibility that enteric glia constitute a previously unrecognized disease target in pathologies associated with intestinal barrier dysfunction, notably inflammatory bowel disease, necrotizing enterocolitis, irritable bowel syndrome, diabetes, autoimmune disease and neurotrophic virus infection of the gut.     

The role of tactile feedback in laparoscopic surgery

Two experiments aiming at comparing palpation with gloved fingers, conventional laparoscopic instruments, and a laparoscopic instrument with a sensor array attached to its end effector are described. The sensor array provides the surgeon with visually presented tactile information. Fifteen subjects were asked to discriminate hardness and size of objects (rubber balls hidden in pig's intestine) with the 3 palpation methods. The experiments showed that the gloved fingers are better at differentiating hardness and size compared with conventional laparoscopic instruments and the instrument with sensor. There was no significant difference between conventional instruments and the instrument with sensor, although the results showed a higher average score with the instrument with sensor. This indicates that visual presentation may not be an ideal way of presenting tactile information. It also indicates that the presence of the array does not make the task more difficult.     

Shift in imaging modalities of the spine through 25 years and its impact on patient ionizing radiation doses

STUDY DESIGN: Retrospective. OBJECTIVE: To explore the shift in modalities when diagnosing the spine in the years 1979-2003. To see how this shift, together with a radiation protective policy, have influenced on the ionizing radiation doses. SUMMARY OF BACKGROUND DATA: The shift from CT/myelography to MR when diagnosing the spine is well known. To what extent this has changed the radiation doses has to our knowledge not yet been published. METHODS: Activity reports from a department of radiology have been reviewed. Relevant radiation doses estimates have been obtained from the Norwegian Radiation Protection Authority. RESULTS: MRI was introduced in 1992 and has been used increasingly since then. Conventional X-ray to the spine has been practically unchanged. Myelography and CT decreased markedly after the introduction of MRI. The total number of examinations of the spine has increased, but the radiation doses given have decreased since 1993. CONCLUSIONS: The introduction of MRI together with a radiation protective policy have reduced the ionizing radiation doses given to this population, in spite of an increase in the total number of examinations of the spine.     

Retroperitoneal benign schwannoma. Report of a new case

The schwannoma is a tumor resulting from the Schwann cells of neural shwath, being its retroperitoneal localization quite unusual. This tumor is clinically unspecified and in most of the cases it originates symptoms coming from the compression of the close structures when its localization is retroperitoneal. Its diagnosis is quite often fortuitous being confirmed by anatomopathological study afterwards. The treatment is surgical radical exeresis with subsequent followup. We report a new case of this uncommon retroperitoneal pathology in a female patient showing a nonspecific clinic. Two years after the surgery she remains asymptomatic without any radiological evidence of recidive.     

Prevention of bedside errors in transfusion medicine (PROBE-TM) study: a cluster-randomized, matched-paired clinical areas trial of a simple intervention to reduce errors in the pretransfusion bedside check

BACKGROUND: Transfusion of the incorrect blood component is a frequent serious incident associated with transfusion and often involves misidentification of the patient and/or the unit of blood. The objective of this study was to assess the effect of a simple intervention designed to improve performance of the bedside check and to observe the durability of any effect. The intervention was a tag on blood bags reminding staff to check the patient's wristband. The tag was positioned in such a way that the transfusionist was required to remove the tag to spike the unit. STUDY DESIGN AND METHODS: The intervention was tested in a multicenter cluster-randomized controlled trial incorporating short-term and long-term follow-up periods. The primary endpoint was the proportion of patients transfused with red cell units for whom the key elements of the bedside check were all correctly completed. RESULTS: Fifteen matched-paired clinical areas at 12 participating hospitals in six countries were included in the trial. Combining data from all participating hospitals, the bedside check was correctly performed in 37 percent of transfusions during the baseline audit period. There was no evidence of a favorable effect of the intervention immediately after its introduction (pooled odds ratio, 1.09; 95% confidence interval, 0.54-2.17). There was similarly no evidence of a favorable effect after continued use of the intervention for an additional 8 weeks. CONCLUSIONS: A simple intervention in the form of a barrier warning label on blood bags reminding staff to check the patient's wristband failed to improve bedside transfusion practice. The robust study design developed for this study could be applied to investigate other interventions to improve the safety of bedside transfusion practice.     

Rapid assessment of recognition efficiency and functional capacity of antigen-specific T-cell responses

It is increasingly recognized that cells within an antigen-specific CD8 T-cell population may be diverse in recognition efficiency for target, which may significantly affect the overall efficacy of the response in clinical settings such as viral infections and cancer. CD8 T cells with seemingly identical antigen specificity, particularly those elicited by cancer vaccines, may be heterogeneous for sensitivity and recognition efficiency for the cognate peptide and functional state in vivo. Analysis of individual T-cell clones derived from an antigen-specific T-cell population would provide an accurate assessment of the overall response; however, this is time- and labor-intensive, preventing rapid and routine assessment of patient samples from clinical trials. By stimulating antigen-specific T cells that otherwise appear homogeneous on tetramer staining with graded amounts of cognate peptides, the authors show that individual cells downmodulate surface T-cell receptors (TCR) and thus lose tetramer reactivity with variable dynamics within the T-cell population. The dynamics of TCR downregulation represent an accurate assessment of an individual cell's antigen sensitivity, recognition efficiency, and relative functional state within an antigen-specific population and have direct correlation to killing capacity by chromium release as well as degranulation by CD107 mobilization. Furthermore, despite correlation of average T-cell function by all three techniques, TCR downregulation uncovered heterogeneity in T-cell responses after vaccination among patient samples directly ex vivo. When examined using this novel technique, antigen-specific T cells elicited by vaccination with heteroclitic peptides exhibited significantly different recognition efficiencies for the heteroclitic versus native peptides, translating into differences in functional responses. With advancing cancer vaccine trials, the capacity to detect and functionally characterize antigen-specific T-cell responses in detail is critical. Techniques, as presented here, that rapidly assess the overall antigen sensitivity, recognition efficiency, and functional status of patients' T-cell responses will guide future vaccine trials and immunotherapies.     

Three-dimensional ultrasonography can detect the modulation of kidney volume in two-kidney, one-clip hypertensive rats

As volume changes are a typical finding in the two-kidney, one-clip hypertensive rat model (2K1C), it is of interest to investigate within what time frame these volume changes occur and their relation to hypertension. Kidney volume changes in Wistar rats were measured by three-dimensional (3D) ultrasonography (USG). Clipped induced stenosis was applied to the left renal artery in 11-wk-old animals (n = 8), using age-matched nonclipped rats as controls (n = 7). Ultrasonographic recordings were made before clipping and, thereafter, weekly with corresponding systolic blood pressure and body weight measurements. The nonclipped kidney showed increased volume at week 2, 5 and 7. Three wk after clipping, clipped kidneys were smaller than the nonclipped kidneys (0.47 ± 0.11 mL versus 1.28 ± 0.07 mL). No difference was found between the left and right kidney in the control group at any week. Blood pressure was significantly higher in the 2K1C hypertensive group 4 weeks after clipping (201 ± 16 versus 139 ± 4 mm Hg) with stable blood pressure thereafter. Three-dimensional USG showed that clipping caused a decrease in kidney volume from week 3 in the clipped kidney and a volume increase in the nonclipped kidney at week 2. A significant increase in blood pressure appeared after week 4. (E-mail: Knut.Matre@med.uib.no)