Effect of dietary fish oil on selected inflammatory markers in pigs.

The present study tested a hypothesis that dietary fish oil (eicosapentaenoic acid+docosahexaenoic acid) in a commonly achievable dose ameliorates a systemic inflammation in pigs. Two groups of pigs of 16 animals each were fed a diet with either 2.5% of fish oil (F) or a control diet with 2.5% of palm oil (P). After 70 days of fattening, eight F and eight P pigs were challenged (F+; P+) i.v. by lipopolysaccharide. After 3 h, all pigs were sacrificed and blood, liver and visceral adipose tissue (VAT) samples were taken. No significant effect (P>0.05) of dietary oil on the feed intake and daily weight gain was found out. Less neutrophils (16.8% v. 28.8%; P0.05) between F+ and P+ pigs in the peroxisome proliferator-activated receptor γ, GPR120, Adipor1 and Adipor2 (adiponectin receptor) gene expression, respectively, was established; plasma adiponectin was the same (21.1 ng/ml) in F+ and P+ pigs. In comparison with the P+ pigs, increased expression of the lipopolysaccharide-binding protein (LBP) gene and intercellular adhesion molecule 1 (ICAM1) gene was found out in the liver of the F+ pigs; expression of the tumor necrosis factor α (TNFα) gene was higher in the liver but lower in the VAT of the F+ pigs (P<0.05). The F+ pigs had higher (P<0.05) plasma concentration of both anti-inflammatory cytokine interleukin-4 (0.46 v. 0.04 ng/ml) and pro-inflammatory TNF-α (13.41 v. 7.72 ng/ml). It was concluded that dietary fish oil at the tested amount had a negligible effect on expression of the evaluated receptor genes and plasma adiponectin, and had an ambiguous effect on expression of cytokine genes and plasma cytokine levels.

Diagnostic accuracy and agreement between whole-body diffusion MRI and bone scintigraphy in detecting bone metastases.

PURPOSE: This study was done to determine the diagnostic value of whole-body magnetic resonance using diffusion-weighted imaging with background suppression (WB-DWIBS) for detecting bone metastases compared with whole-body bone scintigraphy (WB-BS). MATERIALS AND METHODS: Twenty-three patients with solid tumours underwent both WB-DWIBS imaging and WBBS. A nuclear medicine specialist interpreted WB-BS images and two blinded radiologists, first independently and then jointly, interpreted the WB-DWIBS images by completing a reading grid categorising the skeletal segments. Cohen's k statistic was used to determine interobserver agreement in reading the WB-DWIBS images and the agreement between WB-BS and WB-DWIBS. Sensitivity and specificity were calculated per patient and per lesion. RESULTS: Interobserver agreement in reading the WBDWIBS images was substantial or good, with κ=0.68. Analysis of agreement between the nuclear physician's and the radiologists' readings provided κ=0.87 [95% confidence interval (CI)=0.76-0.98)] Per-lesion analysis gave a sensitivity of 80% (95% CI=75-85) and a specificity of 98.2% (95% CI=96.5-99.8). CONCLUSIONS: We found a good level of interobserver agreement for the WB-DWIBS images and an excellent level of agreement in the subjective judgement of presence or absence of disease between WB-BS and WB-DWIBS after consensual double reading. WB-DWIBS has the same specificity as WB-BS in detecting bone metastases. The anatomical sites exhibiting the highest level of disagreement between WB-DWIBS and WB-BS are the pelvis, the coccyx, and the sternum, all sites at which detection with WB-BS has the greatest limitations.

γδ T lymphocytes are recruited into the inflamed uterus of bitches suffering from pyometra.

Very little is known about the occurrence of immune system cells in the canine uterus. The aim of this study was to generate information about lymphocyte subsets that are present in the healthy canine uterus and that are recruited under inflammatory conditions caused by pyometra. Using immunohistochemistry and flow cytometry, a significant influx of γδ T lymphocytes was found in pyometra samples mainly due to recruitment of γδ(+)/CD8(-) T lymphocytes. The relative expression of genes encoding selected cytokines/chemokines was evaluated in samples from healthy and pyometra-affected uteri. Expression of pro-inflammatory cytokines (including IL-1ß, TNF-α, IL-8, IL-17 and IFN-γ) and chemokines (including CXCL10, CCL4 and CCL5) was upregulated in pyometra samples confirming the presence of inflammation. In contrast, the expression of the homeostatic chemokine CCL25 and of the anti-inflammatory cytokine IL-10 was downregulated and unchanged, respectively.

Characterization of CD34⁺ thymocytes in newborn dogs.

Using two-color flow cytometry, we characterized CD34(+) cells in the newborn canine thymus. CD34(+) thymic cells comprised approximately 5% of cells recovered by thymus tissue teasing and both large and small thymocytes have been present in this population, the former being 7-12 times more frequent. All CD34(+) cells expressed the pan-leukocyte antigen CD45. The expression of CD44 profile on the large and small CD34(+) thymocytes differed: almost all large CD34(+) cells were CD44(+), while only 75% of small CD34(+) thymocytes co-expressed the CD44 antigen. We have previously described that CD172α is present on the surface of CD34(+) bone marrow cells in dogs. In the thymus, CD172α was expressed on 5-10% and less than 5% of large and small CD34(+) cells, respectively. Some CD34(+) thymocytes also co-expressed T-lineage-specific markers like CD3, CD4, CD8, TCR1 and TCR2. Their expression increased during the large-to-small thymocyte transition. Based on our findings we suggest that thymocyte progenitors enter their primary differentiation center as large CD34(+), CD44(+), CD45(+) and CD172α(+) cells. T-cell specific markers appear on their surface at early stages of differentiation. As the size of progenitors decreases with terminal primary differentiation, the CD34, CD44, and CD172α surface markers are down-regulated.

Reproducibility and variability of global and regional dyssynchrony parameters derived from phase analysis of gated myocardial perfusion SPECT.

AIM: The aim of the study was to assess the reproducibility (R) and variability of quantitative parameters derived from Cedars-Sinai QGS software for phase analysis of G-SPECT in 39 coronary artery disease (CAD) patients with or without severe heart-failure (HF). METHODS: Phase standard deviation (s) and entropy (e) are global parameters that quantify dyssynchrony. Regional measures of dyssynchrony were also computed including differences between the lateral wall versus the septal wall (DmW) and differences between the averages of midventricular lateral versus midventricular septal segments (DmS). RESULTS: Global parameters e and s and regional parameters DmW and DmS exhibit excellent values of R=0.92, 0.99, 0.99 and 0.96, respectively. In regional parameters DmW and DmS there is a significant variability in individual scoring assessed by a standard error of measurement of =9.17 and 21.7, respectively. The box plots of e in patients with or without HF do not show any significant superimposition, while the box plots of s and DmW show a partial overlap mainly due to the significant variability of s and DmW within patients with HF. Conversely the box plots of DmS in patients with or without HF show a significant overlap due to the great variability of DmS within patients with HF. CONCLUSION: Regional parameters derived from phase analysis of G-SPECT studies are not useful in the individual assessment of dyssynchrony in CAD patients either due to large variability in individual scoring and to a large heterogeneity in HF patients. Global parameters (e and s) exhibit both an excellent reproducibility. Nonetheless, e seems to perform better than s in individual assessment of dyssynchrony due to a better separation between HF and non HF patients. Using the QGS software approach no manual intervention is necessary to ensure a good reproducibility of global parameters.

Salmonella enterica serovar Typhimurium and Enteritidis infection of pigs and cytokine signalling in palatine tonsils.

Pigs are considered as one of the major sources of zoonotic strains of Salmonella enterica for humans. Out of many S. enterica serovars, S. Typhimurium dominates in pigs, however, in several countries in Central Europe, S. Enteritidis is also quite frequent in pig herds. In this study we therefore compared the colonisation of pigs with S. Typhimurium and S. Enteritidis. We found that 3 weeks after infection S. Enteritidis 147 colonised the intestinal tract in higher quantities but was shed in faeces in lower quantities than S. Typhimurium 17C10. In a second experiment we found out that S. Enteritidis 147 and its SPI-1 and SPI-4 mutants increased proinflammatory cytokine (IL-1ß and IL-8) signalling in the ileum 5 days post infection. On the other hand, independent of SPI-1 or SPI-4, S. Enteritidis 147 suppressed expression of IL-18, MCP1, TLR2, CD86, IL-7, IL-10 and IL-15 in the palatine tonsils. The suppression of cytokine signalling may facilitate the initial colonisation of the palatine tonsils by Salmonella. Moreover, immune suppression may also influence pig resistance to opportunistic pathogens and Salmonella infection in pigs thus may become an issue not only in terms of pork contamination but also in terms of affecting the immunological status of pig herds.

Passive immunisation of post-weaned piglets using hyperimmune serum against experimental Haemophilus parasuis infection.

The protective role of hyperimmune serum in the prevention of Haemophilus parasuis infections in post-weaned piglets was assessed by experimental challenge. The hyperimmune serum was obtained from a pig vaccinated with a commercial vaccine against Glässer's disease. Thirty-eight weaned piglets were divided into four groups: three groups were immunised intramuscularly with 10 ml of hyperimmune serum and one group consisted of unimmunised control animals. All piglets were subsequently infected intraperitoneally with H. parasuis serotype 5 at different times after immunisation. The use of hyperimmune serum provided the piglets with partial protection against experimental infection. The levels of protection indirectly depend on time between serum inoculation and challenge infection. The best protection of piglets against experimental infection was obtained in the group immunised 1 week before inoculation; the same group in which the highest levels of antibodies were detected at the time of challenge.

Experimental oral and ocular Encephalitozoon cuniculi infection in rabbits.

Encephalitozoon cuniculi is an obligate intracellular pathogen that has a wide host distribution, but primarily affects rabbits. The aim of this study was to characterize both the cell-mediated and the antibody response in rabbits after experimental infection using 2 different infection routes: oral and ocular. SPF rabbits were infected with low (10³ spores) and high (107 spores) infection doses. Monitored parameters included clinical signs, detection of spores in urine, antibody response detected with ELISA, and cell-mediated immunity detected by antigen-driven lymphocyte proliferation. At week 13 post-infection, half of the rabbits in each group were suppressed by intramuscular administration of dexamethasone. At week 18 post-infection, animals were euthanized. Clinical signs were mild with exacerbation after immunosuppression. Spores in urine and antigen-specific cell-mediated immunity were detected from weeks 5 and 4 post-infection, respectively. Specific IgM was detected 1 week after infection, and IgG antibodies followed 1 week later in rabbits infected with the high dose. Immunological responses were dose dependent. The authors can conclude that both oral and ocular experimental infection with E. cuniculi resulted in an immune response of the infected animals. Rabbits could be used as an experimental model for the study of ocular microsporidiosis.

The effect of activity outside the field of view on image quality for a 3D LSO-based whole body PET/CT scanner.

The purpose of this study was to quantify the influence of outside field of view (FOV) activity concentration (A(c)(,out)) on the noise equivalent count rate (NECR), scatter fraction (SF) and image quality of a 3D LSO whole-body PET/CT scanner. The contrast-to-noise ratio (CNR) was the figure of merit used to characterize the image quality of PET scans. A modified International Electrotechnical Commission (IEC) phantom was used to obtain SF and counting rates similar to those found in average patients. A scatter phantom was positioned at the end of the modified IEC phantom to simulate an activity that extends beyond the scanner. The modified IEC phantom was filled with (18)F (11 kBq mL(-1)) and the spherical targets, with internal diameter (ID) ranging from 10 to 37 mm, had a target-to-background ratio of 10. PET images were acquired with background activity concentrations into the FOV (A(c)(,bkg)) about 11, 9.2, 6.6, 5.2 and 3.5 kBq mL(-1). The emission scan duration (ESD) was set to 1, 2, 3 and 4 min. The tube inside the scatter phantom was filled with activities to provide A(c)(,out) in the whole scatter phantom of zero, half, unity, twofold and fourfold the one of the modified IEC phantom. Plots of CNR versus the various parameters are provided. Multiple linear regression was employed to study the effects of A(c)(,out) on CNR, adjusted for the presence of variables (sphere ID, A(c)(,bkg) and ESD) related to CNR. The presence of outside FOV activity at the same concentration as the one inside the FOV reduces peak NECR of 30%. The increase in SF is marginal (1.2%). CNR diminishes significantly with increasing outside FOV activity, in the range explored. ESD and A(c)(,out) have a similar weight in accounting for CNR variance. Thus, an experimental law that adjusts the scan duration to the outside FOV activity can be devised. Recovery of CNR loss due to an elevated A(c)(,out) activity seems feasible by modulating the ESD in individual bed positions according to A(c)(,out).

Lactoferrin in canine sera: a pyometra study.

The concentration of lactoferrin was measured in canine sera from groups of healthy male dogs as well as pregnant and non-pregnant female dogs and was compared with that of bitches with pyometra. Lactoferrin concentrations were higher in bitches with pyometra. The role of elevated lactoferrin concentrations in the suppression of lymphocyte activity was examined in sera from bitches with pyometra in a series of investigations. Although the sera from bitches with pyometra were capable of suppressing lymphocyte activity, lactoferrin was not found to be involved in this action.

Age-related changes in selected haematology parameters in rabbits.

Even though there is an abundance of information on the reference values of haematological parameters in adult rabbits, a little is known about the changes in haematology in newborn rabbits or during their postnatal development. Therefore, the aim of our study was to investigate changes in red blood cells (RBC), white blood cells (WBC) and differential leukocyte counts in SPF New Zealand White rabbits from the age of one day to 20 weeks. Significant age-related changes during the first four weeks of life were detected. These included an increase of RBC and WBC, reversal of the neutrophil/lymphocyte ratio and increase of total counts of eosinophils and basophils. From the age of six weeks of life, all of the studied haematological parameters were comparable to those of adult rabbits.

Cross-reactive anti-human monoclonal antibodies as a tool for B-cell identification in dogs and pigs.

We have characterized a panel of commercially available anti-human monoclonal antibodies (mAbs) suitable for B-cell identification in pigs and dogs. The specificities of the mAbs were against CD20, CD21, CD22, and CD86. In addition to HM57, originally raised against human CD79alpha the broad cross-reactivity of which was documented more than 10 years ago, we recommend here a panel of several other mAbs as a useful tool for immunophenotyping and multicolor flow cytometry of canine and porcine B-lymphocytes. All six investigated antibodies did bind weakly to either canine or porcine lymphocytes (or both), but considerable weaker than for the human control cells. Four of them did bind to canine or porcine spleen section in immunohistochemistry. Monoclonal antibody against CD22 (clone RFB-4) was the only antibody in the tested panel the cross-reactivity of which was confirmed by Western blot. The advantages and limits of cross-reactive mAbs in studies on animal B-cells are discussed.

Hysterectomy leads to fast improvement of haematological and immunological parameters in bitches with pyometra.

OBJECTIVES: To investigate whether a combination of hysterectomy and antibiotic treatment leads to an improvement of altered haematological and immunological parameters in bitches affected by pyometra. METHODS: Blood samples obtained from 13 bitches affected by pyometra were investigated before hysterectomy and seven days later for a total and differential leucocyte count, activity of neutrophils and lymphocytes, and quantification of total serum immunoglobulins, lysozyme and circulating immune complexes. RESULTS: The parameters most affected included changes in blood profile (leucocytosis because of neutrophilia or leucopenia) and inhibition of lymphocyte activity. Seven days after hysterectomy, all affected parameters returned to normal levels comparable to clinically healthy dogs. CLINICAL SIGNIFICANCE: Application of immunostimulating therapy is not necessary to manage changes in blood cell counts and suppression of lymphocyte activity in bitches with pyometra. Removal of the infected uterus, being the source of infection, leads to improvement.

Commercially available rabbit anti-human polyclonal antisera as a useful tool for immune system studies in veterinary species.

We have used selected rabbit anti-human polyclonal antibodies as an example of useful and easily available tools for studies on immune system structure and development in important veterinary species, many of which also represent animal models in biomedicine. The cocktail of anti-human Igkappa-FITC/anti-Iglambda-RPE F(ab')(2) fragments was used for two-colour and, in combination with the cross-reactive anti-CD79alpha monoclonal antibody HM-57, for three-colour flow cytometry of canine, feline, bovine and porcine peripheral B-cells. A possible application of such immunoreagents in studies on primary B-cell differentiation has been suggested in pigs; the same approach can be used in other species of interest. Rabbit anti-human lactoferrin-FITC F(ab')(2) fragment was used for visualizing neutrophils in dogs, pigs and cattle and an application for two-colour immunophenotyping of canine granulocyte subsets has been designed. Affinity isolated rabbit anti-human CD3 and anti-human TdT have been shown to represent a ready-to-use tool for in situ studies on primary T-lymphopoiesis in pigs with possible extensions both to the B-lineage development in pigs and other animal models. Altogether, our study show that carefully selected polyclonal antibodies available on the market may possess broad cross-reactivity with important applications in veterinary research.

Early postnatal development of the immune system in piglets: the redistribution of T lymphocyte subsets.

In this study, we have characterised postnatal changes in T lymphocyte subsets, especially gammadelta T lymphocytes, in blood, spleen and lymph nodes. Detection was carried out using two-colour flow cytometry and three-colour immunohistochemistry. During ontogeny, there was a significant increase in the total percentage of gammadelta T cells in the spleen and blood. In the lymph nodes, there were no age-dependent changes in the total percentage of gammadelta T cells, but the percentage of the gammadeltaTCR+CD8+ subpopulation significantly increased. The tissue distribution of gammadeltaTCR+CD8+ and gammadeltaTCR+CD8- cells in the lymph nodes is random and not collocated with a particular area of the organ. Furthermore, postnatal development was characterised by an increasing frequency of CD8+CD3+CD4-gammadeltaTCR-, which was compensated by a decreasing proportion of CD4+ lymphocytes. Double positive CD4+CD8+ lymphocytes were rare during the first month of life and a significant age-dependent increase of these cells was found in all the compartments monitored.

Experimental Actinobacillus pleuropneumoniae infection in piglets with different types and levels of specific protection: immunophenotypic analysis of lymphocyte subsets in the circulation and respiratory mucosal lymphoid tissue.

Actinobacillus pleuropneumoniae (APP) infection in piglets results in severe and fatal fibrinous hemorrhagic necrotizing pneumoniae. The aim of our study was to analyze changes in lymphocyte subset distribution in peripheral blood, bronchoalveolar lavage fluid (BALF) and tracheobronchal lymph nodes (TLN) in non-immune piglets upon a challenge with a high dose of APP and to compare the quality of such changes in unprotected piglets with counterparts exhibiting specific immunity mediated by high titers of colostrum-derived APP-specific antibodies and/or a low dose APP infection in the early postnatal period. Challenge with APP resulted in a massive increase in CD8-negative gammadelta T-cells in parallel with a reduction in numbers of CD3-CD8low cells in BALF independent of the type and level of immunity and this seems to be a general phenomenon associated with experimental infection. An increase in B-lymphocyte numbers in TLN was another characteristic feature accompanying APP infection in all experimental groups. In piglets with colostrum-derived APP-specific antibodies, this was associated with higher relative numbers of IgM+CD2+ lymphocytes in TLN, while B-cells with the CD2- surface phenotype apparently expanded in the absence of passive humoral immunity.

Lymphatic organ development in dogs: major lymphocyte subsets and activity.

In the present study, we have characterized lymphocyte subsets and activity in peripheral blood, spleen, mesenteric and popliteal lymph nodes in pups from birth till the age of one month and compared the results with the situation in the group of three adult dogs. In neonatal pups, lower numbers of CD3(+) T-cells were detected in both the spleen and peripheral blood than in lymph nodes. In contrast to the other compartments, CD21(+) B-cells prevailed in the spleen, which resulted in low values (<1) of the CD3(+)/CD21(+) ratio. Low numbers of CD8(+) lymphocytes were characteristic in all compartments immediately after birth; consequently a high CD4(+)/CD8(+) ratio has been calculated. Postnatal development was characterized by an increasing frequency of CD8(+) lymphocytes in all organs studied. Another typical feature of the early period of life was a relative decrease of B-cell numbers, which was compensated by an increasing proportion of T-lymphocytes, particularly in the peripheral blood and spleen. DNA synthesis in newborn pups' cells as measured by in vitro thymidine incorporation was surprisingly high in non-stimulated control samples, notably in the spleen. Further development of lymphocyte activity was characterized by the decline in spontaneous activity in all organs. Stimulation indices upon mitogen-induced proliferation increased proportionally to the decrease in spontaneous activity. Based on our experimental data, we have concluded that pups are born with a relatively competent immune system the structure of which, however, markedly develops during a few postnatal weeks.

Recent applications of the sentinel lymph node concept: preliminary experience in prostate cancer.

AIMS AND BACKGROUND: Following the widespread use of radioguided surgery (RGS) in melanoma and breast cancer, we applied this new surgical strategy to prostate cancer (PC). The aims of this study were 1) to evaluate the accuracy of RGS in the detection of prostatic sentinel lymph nodes (SLN), and 2) to verify if pelvic lymphadenectomy (LAD) is an accurate means to detect solitary micrometastases. STUDY DESIGN: We investigated 48 patients with PC confirmed by transrectal biopsy who underwent radical prostatectomy and bilateral LAD. A dose of 99mTc-labeled nanocolloid particles was injected into the prostate after needle positioning by ultrasonography. Serial imaging was obtained with a gamma camera, identifying 1) the first radioactive lymph node (sentinel lymph node, SLN); 2) other radioactive lymph nodes, and 3) non-active lymph nodes. RESULTS: Forty-three SLNs were identified in 48 patients. Twenty SLNs were located at unusual sites with respect to the extent of conventional LAD. Five SLNs were positive for micrometastases and two of these were located outside the usual LAD area. No micrometastases were found in any of the remaining lymph nodes (active and non-active). CONCLUSIONS: These preliminary results are in agreement with the few previous scientific contributions available on this topic and indicate that it is possible to reduce the extent and duration of surgery and necessary to reevaluate the conventional sites of lymphatic drainage.

Lymphocyte subsets in peripheral blood of dogs--a flow cytometric study.

Slight differences in the results of papers describing lymphocyte subsets distribution in the peripheral blood of healthy dogs may be explained by differences in monoclonal antibody clones and sources, breed and age of animals examined, methods of sample treatment, or methods of result analysis. In this paper, we described the effect of sample processing and of sample storage as well as the effect of age, breed, and gender of dogs on lymphocyte subset distribution. No significant differences were found between samples processed following a whole-blood lysis method and samples processed after density gradient separation. Furthermore, no significant differences were found between samples processed within 2h after collection and those stored at 4 degrees C for 12-16 h before processing. Age-related changes were evident in lymphocyte subset distribution in the peripheral blood of 38 Beagles divided according to their age into the six groups: (1) 5-6 days; (2) 2 months; (3) 6 months; (4) 1-2 years; (5) 3-5 years; and (6) >5 years. The percentage of B-lymphocytes (CD21-like positive cells) in the peripheral blood of newborn pups was 39.5+/-5.7 and decreased with advancing age. The percentage of CD8+ lymphocytes was 7.7+/-3.4 after birth and increased with advancing age. No age-related changes were observed in the percentages of CD4+ lymphocytes. The CD4+:CD8+ ratio decreased with advancing age. No significant age-related change was observed for lymphocytes bearing the gammadelta-TCR. Some breed differences were evident. Adult (1-5-year-old) Beagles, German Shepherds, Dalmatians, and Dachshunds were examined. The percentages of lymphocytes were higher in Beagles and Dachshunds than in Dalmatians and German Shepherds. The highest and the lowest absolute lymphocyte counts were found in Beagles and German Shepherds, respectively. As a consequence, German Shepherds showed the lowest absolute counts of the individual lymphocyte subpopulations and the widest neutrophil:lymphocyte ratio. Dalmatians showed the lowest percentage of CD3+ cells, the highest percentage of CD21+ cells, and the lowest CD4+:CD8+ ratio. German Shepherds showed the lowest percentage of CD21+ cells and the highest CD4+:CD8+ ratio. Females in Beagles and Dachshuns had nonsignificantly higher percentages of total lymphocytes, CD3+, CD4+, and nonsignificantly lower percentages of CD21+ lymphocytes. We concluded that there are age-, breed-, and perhaps also gender-related differences in lymphocyte subset distribution in the peripheral blood of dogs. Therefore, there is need to use appropriate control group in the experimental protocols. Among-breed differences could explain, at least partly, breed predisposition for some diseases.

Crutch handle design: effect on palmar loads during ambulation.

OBJECTIVE: To compare loads, load distributions, pressures, and areas of weight-bearing on the palm for forearm crutches with cylindrical and wide handles during ambulation to determine if one handle type produced greater loads on the carpal tunnel region. DESIGN: Single-group repeated measures of normal adults; descriptive study of patients who were long-term crutch users. Data were collected from six palmar regions using an F-Scan system. SETTING: Center for neuromuscular disorders in a hospital. PARTICIPANTS: Thirty normal volunteers and 6 patients. MAIN OUTCOME MEASURE: Differences in loads for the palmar regions between the two handles, particularly the carpal tunnel region. RESULTS: For the normal adults, significantly greater loads were found in two distal regions for the cylindrical handle and in one proximal region for the wide handle. Distribution of weight-bearing loads showed a similar pattern for both handles with the palm's proximal and distal radial sides having the greatest loads and the carpal tunnel region having the third highest load. The area of weight-bearing was significantly greater for the wide handle than for the cylindrical. CONCLUSIONS: Cylindrical and wide crutch handles have similar load distributions, making it impossible to recommend one type over the other to reduce the occurrence of carpal tunnel syndrome. The wide handle distributes the loads over a greater surface area, producing less focal pressure.