Therapeutic level of functional human alpha 1 antitrypsin (hAAT) secreted from murine muscle transduced by adeno-associated virus (rAAV1) vector

Alpha 1 antitrypsin (AAT) is a serine proteinase inhibitor (serpin). One well-known function of this protein is to inactivate neutrophil elastase and other neutrophil-derived proteinases, and prevent the destruction of pulmonary extracellular matrix. Deficiency of AAT can cause emphysema due to degradation of interstitial elastin by elastase. The majority of circulating AAT is secreted from the liver. Muscle-directed gene therapy using recombinant adeno-associated virus 2 (rAAV2) vectors has been tested to increase the serum levels of AAT. However, inefficient transduction of rAAV2 vector makes it difficult to reach therapeutic levels of AAT in clinical trials and it remains unclear as to whether muscle-secreted AAT is functional. In the present study, we evaluated five serotypes (1, 2, 3, 4, and 5) of rAAV vectors for transduction efficiency in mouse muscle. Results from these studies showed that rAAV1 is the most efficient vector among these serotypes and mediated at least 100-fold higher levels of AAT secretion than the rAAV2 vector. Western blot analysis showed that this murine muscle-secreted human AAT (hAAT) formed a complex with human neutrophil elastase in a dose-dependent manner. An anti-elastase activity assay showed that murine muscle-secreted hAAT inhibited elastase with equal capacity as hAAT purified from plasma. These results provide strong support for the functionality of AAT in ongoing clinical studies of muscle-directed AAT gene therapy.

Donor-derived type II pneumocytes are rare in the lungs of allogeneic hematopoietic cell transplant recipients

Lung injury is a common cause of death and disability. Stem cell-related therapies are widely viewed as offering promise for people suffering from various types of pulmonary diseases, and gender-mismatched bone marrow transplant recipients serve as natural populations in which to study the role of bone marrow-derived stem cells in recovery from pulmonary injury. We evaluated the extent of lung repopulation by type II pneumocyte descendents of adult bone marrow-derived stem cells in allogeneic hematopoietic cell transplant recipients. Recut sections were obtained from five lung biopsy specimens and autopsy lung tissues from four female recipients of transplanted mobilized peripheral blood stem cells or bone marrow from male donors. Sequential immunohistochemistry and fluorescence in situ hybridization was performed on each section to evaluate for Y-chromosome-containing type II pneumocytes. A single Y-chromosome-containing type II pneumocyte was found in one lung biopsy from one hematopoietic cell transplant recipient. After adjustment for the effects of incomplete nuclear sampling, this pneumocyte represented 1.75% of all type II pneumocytes in the biopsy sample. There was no evidence of polyploidy to suggest cell-to-cell fusion. No donor-derived type II pneumocytes were found in samples from the other three patients. In conclusion, repopulation by bone marrow-derived stem cells or their progeny occurs at a low frequency in the lungs of hematopoietic cell transplant recipients. Conversely, proliferation by local stem cell populations appears to be more important for recovery from alveolar injury.

Defective Jak-Stat activation in hepatoma cells is associated with hepatitis C viral IFN-alpha resistance

Interferon-alpha (IFN-alpha) has been widely used to treat viral infections and certain types of cancers. Large numbers of patients with chronic hepatitis C viral (HCV) infection do not respond to IFN and ribavirin combination therapy, and the majority of patients do not respond to IFN monotherapy. The underlying mechanisms of HCV nonresponse to IFN are unknown. In this report, using a HCV subgenomic replicon cell culture system, we show that (1) long-term IFN stimulation can select cells defective for Stat3 activation, and the defect appears to be responsible for HCV IFN resistance in cell culture, (2) HCV subgenomic sequence mutations associated with long-term culture do not appear to be responsible for IFN resistance, (3) expression of the activated Stat3 reverses IFN resistance while a dominant negative form of Stat3 renders an IFN-sensitive cell line resistant to IFN, and (4) the IFN-resistant cell line exhibits enhanced suppressor of cytokine signaling 3 (SOCS3) expression in response to IFN stimulation, and blocking SOCS3 in the IFN-resistant cell line partially restores IFN sensitivity. These findings strongly suggest that the IFN-resistant phenotype in vitro is associated with defective Stat3 activation and an enhanced SOCS3 response but is not associated with viral sequence mutations. Our study implies that long-term IFN stimulation in vitro selects cells that exhibit alterations in the host Jak-Stat signaling pathway, thereby representing a potential mechanism by which HCV resists IFN therapy.

Rab11a immunohistochemical analysis does not distinguish indefinite, low-, and high-grade dysplasia in Barrett esophagus

Our aim was to determine whether p53 and Rab11a immunoreactivity enhance diagnostic assessment of esophageal dysplasia. Histologic sections from 68 cases of Barrett esophagus obtained as part of a 12-institution study were stained with antibodies to p53 and Rab11a, randomized, and coded. The mucosal surface layer and deeper glands were scored blindly on a semiquantitative scale. The correlations between p53 and Rab11a scoring with the consensus diagnosis of dysplasia were analyzed. The histologic scale was as follows: no dysplasia, indefinite, low-grade dysplasia, high-grade dysplasia, intramucosal carcinoma, and invasive carcinoma. Rab11a staining was most prominent in epithelia negative for dysplasia but with regenerative features. There was an inverse relationship between Rab11a staining and findings of surface dysplasia (P < .02, chi(2)). However, statistical significance largely reflected loss of Rab11a immunoreactivity in intramucosal and invasive carcinoma, which was not a diagnostic dilemma. There was a strong positive correlation of p53 immunoreactivity with an increasing degree of epithelial dysplasia and carcinoma (P < .03, chi(2)). Rab11a immunoreactivity did not enhance the diagnostic assessment of dysplasia in Barrett esophagus. The previously reported positive correlation of p53 immunoreactivity with the presence of dysplasia in Barrett esophagus was confirmed.

Pathology as the enabler of human research

Academic Pathology is a key player in human molecular science and in the powerful initiatives of the National Institutes of Health. Pathologists generate data crucial to virtually every molecular study of human tissue, and have the necessary skills and authority to oversee processing of human tissues for research analysis. We advocate that Academic Pathology is optimally positioned to drive the molecular revolution in study of human disease, through human tissue collection, analysis, and databasing. This can be achieved through playing a major role in human tissue procurement and management; establishing high-quality 'Pathology Resource Laboratories'; providing the scientific expertise for pathology data sharing; and recruiting and training physician scientists. Pathology should position itself to be the local institutional driver of technology implementation and development, by operating the resource laboratories, providing the expertise for technical and conceptual design of research projects, maintaining the databases that link molecular and morphological information on human tissues with the requisite clinical databases, providing education and mentorship of technology users, and nurturing new research through the development of preliminary data. We also consider that outstanding pathology journals are available for the publication of research emanating from such studies, to the benefit of the pathology profession as an academic enterprise. It is our earnest hope that Academic Pathology can play a leading role in the remarkable advances to be made as the 21st century unfolds.

Bone marrow-derived stem-cell repopulation contributes minimally to the Type II pneumocyte pool in transplanted human lungs

BACKGROUND

Lung transplant recipients are vulnerable to immunologic, infectious, ischemic, and toxic pulmonary injuries. The authors investigated whether type II pneumocytes in the lungs of cross-gender lung transplant patients show genotypic evidence to support repopulation of the lung by stem cells of bone marrow origin, and whether the degree of repopulation was related to rejection history.

METHODS

Recut sections were obtained from lung biopsy specimens from seven male recipients of transplanted lungs from female donors. Sequential immunohistochemistry and fluorescence in situ hybridization was performed on each section to evaluate for Y-chromosome-containing type II pneumocytes.

RESULTS

Y-chromosome-containing type II pneumocytes were found in 9 of 25 biopsy specimens from 5 of 7 gender-mismatched male lung transplant recipients, and accounted for 0% to 0.553% of type II pneumocytes. There was no evidence of polyploidy to suggest cell-cell fusion. The number of type II pneumocytes of male karyotype showed a statistically significant relationship to the cumulative number of episodes of acute cellular rejection.

CONCLUSIONS

Lung transplant recipients develop low levels of pneumocyte repopulation by bone marrow-derived stem cells or their progeny. These cells contribute minimally to the type II pneumocyte proliferation that is often present in these patients as a sequela to alveolar injury.

Anaesthetists should wear gloves--touch sensitivity is improved with a new type of thin glove

BACKGROUND

Sterile gloves should be worn for all invasive procedures. However, loss of touch sensitivity when wearing gloves leads to poor compliance among anaesthetists in the UK. Our aim was to investigate whether new surgical glove types, such as extra-thin or latex-free gloves, offer any advantage in touch sensitivity.

METHODS

The skin-pressure sensibility threshold of the gloved pulp of the dominant index finger was established in 24 anaesthetists using nine self-made modified von Frey hairs. The range of forces generated by nylon monofilaments was evenly distributed between 0.5 and 17 mN. The gloves tested were latex Biogel standard, latex-free Biogel Neotech, and extra-thin latex Ansell microthin surgical gloves. The different glove types were assessed in a counterbalancing algorhithm, the individual was blinded, and the filaments were applied in random order.

RESULTS

The median threshold force to touch was significantly lower for the extra-thin surgical gloves in comparison to the standard latex (P = 0.014) and latex-free gloves (P = 0.001). There was no significant difference between the standard latex and latex-free gloves (P = 0.166).

CONCLUSION

We have demonstrated that wearing extra-thin surgical gloves offers increased touch sensitivity. This may improve dexterity when carrying out delicate invasive procedures. Latex-free surgical gloves performed similar to standard latex gloves. Our findings should encourage more widespread glove use among anaesthetists.

One-year protocol liver biopsy can stratify fibrosis progression in liver transplant recipients with recurrent hepatitis C infection

Determinants of progression to cirrhosis in hepatitis C virus (HCV) infection have been well described in the immunocompetent population but remain poorly defined in liver transplant (LT) recipients. This cohort study determines the factors contributing to the development of fibrosis and its rate of progression in the allograft. Predictive factors analyzed include: demographics, host and donor factors, surgery-related variables (cold and warm ischemia time), rejection episodes, cytomegalovirus infection (CMV), and immunosuppression. Over 12 years, 842 adult LTs were performed at our institution; 358 for the indication of HCV. A total of 264 patients underwent protocol liver biopsies at month 4 and yearly after LT. Using the modified Knodell system of Ishak for staging fibrosis, the median fibrosis progression rate was .8 units/year (P < .001). Rapid fibrosis progression (> .8 units/year) was best identified by liver histology performed at 1 year. Donor age > 55 years was associated with rapid fibrosis progression and development of cirrhosis (P < .001). In contrast, donor age < 35 years was associated with slower progression of fibrosis (P = .003). Risk factors for graft loss due to recurrent HCV included recipient age > 35 years (P = .01), donor age > 55 years (P = .005), and use of female donor allografts (P = .03). In conclusion, fibrosis progression in HCV-infected LT recipients occurs at a rate of .8 units/year. Increased donor age has a major impact on disease progression, graft failure, and patient survival. A liver biopsy performed at 1 year posttransplant can help identify those patients more likely to develop progressive disease and may allow better targeting of antiviral therapy.

Interobserver reliability between a nurse and anaesthetist of tests used for predicting difficult tracheal intubation

We examined the interobserver reliability, between a nurse and anaesthetist, of five tests used to predict difficult tracheal intubation: mouth opening; thyromental distance; head and neck movement; mandibular luxation; and assessment of oropharyngeal view. For each test, an anaesthetic nurse and a specialist registrar anaesthetist were trained to use a standard method of examination. Most of the tests had either good or very good reliability. Assessment of mouth opening demonstrated only moderate reliability and assessment of oropharyngeal view demonstrated poor reliability. The interobserver reliability estimates between a nurse and an anaesthetist are similar to those previously demonstrated between two anaesthetists.

Nomenclature of the finer branches of the biliary tree: canals, ductules, and ductular reactions in human livers

The work of liver stem cell biologists, largely carried out in rodent models, has now started to manifest in human investigations and applications. We can now recognize complex regenerative processes in tissue specimens that had only been suspected for decades, but we also struggle to describe what we see in human tissues in a way that takes into account the findings from the animal investigations, using a language derived from species not, in fact, so much like our own. This international group of liver pathologists and hepatologists, most of whom are actively engaged in both clinical work and scientific research, seeks to arrive at a consensus on nomenclature for normal human livers and human reactive lesions that can facilitate more rapid advancement of our field.

Recombinant adeno-associated virus-mediated alpha-1 antitrypsin gene therapy prevents type I diabetes in NOD mice

Type I diabetes results from an autoimmune destruction of the insulin-producing pancreatic beta cells. Although the exact immunologic processes underlying this disease are unclear, increasing evidence suggests that immunosuppressive, immunoregulatory and anti-inflammatory agents can interrupt the progression of the disease. Alpha 1 antitrypsin (AAT) is a multifunctional serine proteinase inhibitor (serpin) that also displays a wide range of anti-inflammatory properties. To test the ability of AAT to modulate the development of type I diabetes, we performed a series of investigations involving recombinant adeno-associated virus vector (rAAV)-mediated gene delivery of human alpha-1 antitrypsin (hAAT) to nonobese diabetic (NOD) mice. Recombinant AAV-expressing hAAT (rAAV2-CB-AT) was administered intramuscularly to 4-week-old female NOD mice (1 x 10(10) i.u./mouse). A single injection of this vector reduced the intensity of insulitis, the levels of insulin autoantibodies, and the frequency of overt type I diabetes (30% (3/10) at 32 weeks of age versus 70% (7/10) in controls). Transgene expression at the injection sites was confirmed by immunostaining. Interestingly, antibodies against hAAT were present in a majority of the vector-injected mice and circulating hAAT was undetectable when assessed 10 weeks postinjection. This study suggests a potential therapeutic role for AAT in preventing type I diabetes as well as the ability of AAV gene therapy-based approaches to ameliorate disease effectively.

The influence of esmolol on the dose of propofol required for induction of anaesthesia

Cardiac output may be an important determinant of the induction dose of intravenous anaesthetic. Esmolol is known to reduce cardiac output, and we examined its effect on the propofol dose required for induction of anaesthesia. The size of the effect seen with esmolol was compared with midazolam co-induction. Sixty patients were randomly allocated to placebo (saline), esmolol (1mg x kg(-1) bolus, followed by an infusion at 250 microg x kg(-1)min(-1)) or midazolam (0.04 mg x kg(-1)) groups. Induction of anaesthesia commenced 3 min following the administration of the study drug, using a Diprifusor set to achieve plasma propofol concentrations of 10 microg x ml(-1) at 5 min. The primary end point used was the propofol dose per kg at loss of response to command. The mean (SD) propofol dose for each group was 2.38 (0.48) mg x kg(-1) for placebo, 1.79 (0.36) mg x kg(-1) for esmolol and 1.34 (0.35) mg x kg(-1) for midazolam (all means significantly different; p < 0.0005). We found that predosing with esmolol reduces the propofol requirements for induction of anaesthesia by 25%.

The pathology of cholestasis

Hepatic formation of bile is critical to survival and is one of the most easily disrupted liver functions. Liver biopsy is performed to obtain a definitive diagnosis of cause, to exclude potential etiologies, or simply to assist in development of a differential diagnosis. Parenchymal changes of cholestasis (feathery degeneration of hepatocytes, dilated bile canaliculi with retained bile, Kupffer cell phagocytosis of bile that has leaked into the sinusoidal space) are nonspecific and may be seen with both nonobstructive and obstructive cholestasis. The portal tract changes of obstruction are characteristic: bile ductular proliferation, inspissated bile in bile ducts, portal tract edema, neutrophilic inflammation, and cholate stasis of periportal hepatocytes. Uncorrected obstruction incites robust fibrogenesis by portal tract myofibroblasts, engendering a characteristic jigsaw pattern of fibrous septa. Diseases with specific histological features include primary biliary cirrhosis, primary sclerosing cholangitis, biliary atresia, and graft-versus-host disease. However, the pathologist is cautioned not to overinterpret the cholestatic liver biopsy and to apply rigorous criteria for specific causal diagnoses. Most of the histological features of cholestasis are nonspecific. Hence, both practicing physician and pathologist should have sound knowledge of the pathology of cholestasis.

Sustained viral response to interferon and ribavirin in liver transplant recipients with recurrent hepatitis C

Recurrent hepatitis C infection is an important cause of progressive fibrosis, cirrhosis, and graft loss following orthotopic liver transplantation. Treatment for posttransplant recurrence of hepatitis C with interferon-based therapy is difficult but results in loss of detectable virus in up to 30% of patients. However, the durability of viral clearance and the associated histologic response in this setting is unknown. The aim of this study was to determine whether viral loss in response to antiviral therapy is durable and associated with improvement in liver histology. All liver transplant recipients who received interferon-based treatment for recurrent hepatitis C virus (HCV) at the University of Florida from 1991 to 2002 were included in this study. Patients who lost detectable HCV after treatment with interferon alone or in combination with ribavirin were followed to assess the durability of viral response and its impact on liver histology. One hundred nineteen transplant recipients were treated with interferon or combination therapy. Twenty-nine (20 men, 9 women; mean age, 54 yrs [range, 42-74 yrs]) lost detectable HCV RNA and remained virus negative for at least 6 months after discontinuing therapy (sustained viral response[SVR]). The mean follow-up after discontinuing therapy was 24.7 months (range, 6-70 mos). Our study cohort included one patient with SVR following interferon monotherapy and 28 patients with SVR following combination therapy with interferon plus ribavirin. All patients remained HCV RNA negative (assessed by polymerase chain reaction or branched-DNA assay) during follow-up of up to 5 years. Liver histology assessed 2 years after treatment showed less inflammation compared with before treatment in 50% and showed no change in 38%. By 3 to 5 years post-treatment (n = 15 recipients), inflammation was reduced in 60% and remained unchanged in 33%. Fibrosis stage at 2 years improved by > or = 1 stage in 27 %, remained unchanged in 38 %, and worsened in 35% despite viral clearance. At 3 to 5 years, the fibrosis stage had improved in 67%, remained unchanged in 13%, and worsened in 20%. Both grade of inflammation and fibrosis stage improved by 3 to 5 years posttreatment compared with baseline histology (p < 0.05). In conclusion, loss of HCV after treatment of recurrent chronic hepatitis C with interferon and ribavirin is durable, and the durability of the SVR is associated with improvement in hepatic inflammation and regression of fibrosis.

Immunity to adeno-associated virus serotype 2 delivered transgenes imparted by genetic predisposition to autoimmunity

Adeno-associated virus (AAV) is widely considered a promising vector for therapeutic gene delivery. This promise is based on previous studies assessing AAVs safety and toxicity, ability to infect nondividing cells, elicit a limited immune response and provide long-term gene expression. However, we now find that earlier studies underappreciated the degree of AAV immunogenicity as well as the extent to which genetic background, through regulation of immune responsiveness, influences the duration of gene expression and thereby the effectiveness of AAV-mediated gene therapy. We evaluated antibody responses in 12 mouse strains to AAV serotype 2 (AAV2) and AAV2-expressed transgene products including green fluorescent protein (GFP), human alpha1-antitrypsin and murine interleukin-10. As expected, all immunocompetent mice administered AAV2 developed serologic evidence of immune responsiveness to the virus. However, a previously unidentified serologic prozone effect was observed suggesting that the concentrations of anti-AAV2 antibodies may have historically been subject to marked underestimation. Furthermore, strains with genetic predisposition to autoimmunity (eg, NOD, NZW, MRL-lpr) specifically imparted a functionally deleterious immune response to AAV-delivered transgene products. These findings suggest that more thorough studies of anti-AAV immunity should be performed, and that genetic predisposition to autoimmunity should be considered when assessing AAV efficacy and safety in humans.

Glucose-responsive expression of the human insulin promoter in HepG2 human hepatoma cells

The concept of insulin production afforded by hepatic gene therapy retains promise as a potential therapy for type 1 diabetes, but the approach has been limited by the need for strict transgene regulation in response to fluctuating levels of both glucose and insulin. Furthermore, while hepatocytes contain various glucose-responsive elements, they lack the appropriate regulated secretory system necessary for insulin release, thereby necessitating the requirement for transcriptional regulation of hepatic insulin production under the direction of a glucose-responsive promoter. To address this, we have evaluated several glucose-responsive promoters that may be used successfully for hepatic insulin production via recombinant adeno-associated virus (rAAV) therapy. Our results suggest that the human insulin promoter represents a strong candidate as a robust, glucose-responsive promoter for regulated hepatic insulin production.

Total fibrous obliteration of main portal vein and portal foam cell venopathy in chronic hepatic allograft rejection

CONTEXT

Chronic hepatic allograft rejection is characterized by arteriopathy and bile duct loss. Pathology of the portal vein or its branches is not considered to play a major role in chronic rejection.

OBJECTIVE

A recent case of chronic rejection with total fibrous obliteration of the portal vein at the hilum and graft loss prompted us to retrospectively analyze cases of failed allografts for portal vein changes.

DESIGN

Six cases of failed hepatic allograft recorded in our files from 1994 to 1998 were selected for the study. For comparison, 4 cases of hepatitis C cirrhosis were included. Clinical features, including arteriograms or Doppler studies, were reviewed whenever available. Sections taken from the hilum and random parenchyma stained with routine hematoxylin-eosin, elastic van Gieson, and Masson trichrome were examined by 3 experienced liver pathologists in a randomized, blinded fashion.

RESULTS

Significant hepatic artery occlusion with foam cell change and bile duct loss was seen in all cases of chronic rejection (3/3), but not in the other cases. Foam cell change in the portal vein at the hilum (3/3) and occasionally into the distal branches (2/3) with variable occlusion of the lumen was seen only in cases of chronic hepatic allograft rejection. Mild luminal narrowing was observed in all the cases of cirrhosis (4/4) as a result of phlebosclerosis, most likely representing a change secondary to portal hypertension. Total obliteration of the portal vein at the hilum was seen in the index case (case 1) only.

CONCLUSION

Portal venopathy can be a significant finding in chronic hepatic allograft rejection and may contribute to graft dysfunction or failure. Two-vessel disease must be considered in cases of chronic hepatic allograft rejection, and pathologists should thoroughly examine the hilum in explanted hepatic allografts.

Gene expression associated with interferon alfa antiviral activity in an HCV replicon cell line

Interferon alfa (IFN-alpha)-based treatment is the only therapeutic option for chronic hepatitis C viral infection. However, the molecular mechanisms of IFN-alpha antiviral activity are not completely understood. The recent development of an HCV replicon cell culture system provides a feasible experimental model to investigate the molecular details of IFN-induced direct antiviral activity in hepatocytes. In this report, we show that IFN-alpha can effectively inhibit HCV subgenomic RNA replication and suppress viral nonstructural protein synthesis. Using cDNA microarray analysis, we also show that the replicon cells have different gene expression profile compared with the parental hepatoma cells (Huh7). IFN-alpha can induce a number of responsive genes in the replicon cells. One of the genes, 6-16 (G1P3), can enhance IFN-alpha antiviral efficacy. In addition, we demonstrate that IFN-alpha can significantly activate STAT3 in hepatoma cells, suggesting that this pathway plays a role in IFN-alpha signaling. In conclusion, our results indicate that IFN-alpha antiviral activity is associated with activation of STAT3-signaling pathway and intracellular gene activation. Our results also suggest that IFN-alpha-induced target genes may play an important role in IFN-alpha anti-HCV activity.

Prevalence of ROPS--equipped tractors and farm/farmer characteristics

Data were collected on tractor safety status and the prevalence of ROPS as part of the Ohio Farm Family Health and Hazard Surveillance Program (FFHHSP) "walk-around" hazard assessments of cash grain farms in central Ohio. Principal operator (PO) characteristics thought a priori to have a possible association with ROPS utilization included age, education, percent time spent farming, total years in agriculture, and previous training in occupational injury prevention. Farm characteristics of interest were farm size, acres of cropland in use, sales value during the past 12 months, and current number of farm workers. Descriptive and logistic regression analyses were conducted to evaluate potential associations between these factors and ROPS utilization patterns. Of 1,044 tractors encountered on 306 farms, 359 (34.4%) were equipped with ROPS, 29 (9.5%) had nothing but ROPS-equipped tractors, and 117 (38.2%) did not have any ROPS-equipped tractors. The absence/presence of ROPS-equipped tractors in our sample was found to vary by several factors, and over a wide range. Results of invariable logistic regression analyses (excluding the relatively small number of tractors manufactured after 1985) indicated that younger POs with at least a high school education who spent more than half their time working in agriculture, employed three or more workers, had 500 or more acres of total farm land and cropland in use, and had a 12-month sales value exceeding $250,000 were more likely to have at least one ROPS-equipped tractor on their farms. However, time spent farming, number of workers, and the 12-month sales value were not strongly predictive in multivariable models. Although more than 20% of the POs in our sample reported having had training in occupational injury prevention, this factor had essentially no value in predicting the absence/presence of ROPS-equipped tractors on their farms. The results of this study illustrate the need for interventions to encourage ROPS retrofitting that target POs with less education and who work on smaller and less productive farms. However, the low overall ROPS utilization rates suggest that all farmers could benefit from intervention efforts.

Cholesterol crystal morphology in acalculous gallbladder disease

BACKGROUND

Biliary crystal morphology is best described in patients with gallbladder stones, but most patients undergoing bile collection for microscopy have a clinical diagnosis of acalculous gallbladder disease. We investigated the morphology of biliary crystals in such patients.

STUDY

Bile was obtained for polarizing microscopy from fresh cholecystectomy specimens of patients with a clinical diagnosis of acalculous or calculous gallbladder disease. Slides for microscopy were prepared by touch contact with bile in freshly opened gallbladder specimens, and following aspiration of gallbladder bile through a 5-French cannula.

RESULTS

Bile was examined from five patients with a clinical diagnosis of acalculous gallbladder disease and five patients with known gallstones. Needle-like cholesterol crystals predominated in most patients without gallstones, whereas plate-like and dot-like crystals were more common in patients with gallstones. All three crystal types were seen in most patients. Crystal morphology was not affected by aspiration of bile through a 5-French cannula.

CONCLUSIONS

Birefringent needles and dots should be recognized as cholesterol crystals during bile microscopy. These crystal morphologies may predominate in some patients with a clinical diagnosis of acalculous gallbladder disease.

Donor T cell-derived TNF is required for graft-versus-host disease and graft-versus-tumor activity after bone marrow transplantation

Previous studies in murine bone marrow transplantation (BMT) models using neutralizing anti-tumor necrosis factor (TNF) antibodies or TNF receptor (TNFR)-deficient recipients have demonstrated that TNF can be involved in both graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL). TNF in these GVHD and GVL models was thought to be primarily produced by activated monocytes and macrophages, and the role of T cell-derived TNF was not determined. We used TNF(-/-) mice to study the specific role of TNF produced by donor T cells in a well-established parent-into-F1 hybrid model (C57BL/6J-->C3FeB6F1/J). Recipients of TNF(-/-) T cells developed significantly less morbidity and mortality from GVHD than recipients of wild-type (wt) T cells. Histology of GVHD target organs revealed significantly less damage in thymus, small bowel, and large bowel, but not in liver or skin tissues from recipients of TNF(-/-) T cells. Recipients of TNF(-/-) T cells which were also inoculated with leukemia cells at the time of BMT showed increased mortality from leukemia when compared with recipients of wt cells. We found that TNF(-/-) T cells do not have intrinsic defects in vitro or in vivo in proliferation, IFN-gamma production, or alloactivation. We could not detect TNF in the serum of our transplant recipients, suggesting that T cells contribute to GVHD and GVL via membrane-bound or locally released TNF.