Comparison of bone healing, as assessed by computed tomography, following tibial tuberosity advancement in dogs with and without autogenous cancellous bone grafts.

AIMS: To objectively compare measures of bone healing, using computed tomography (CT) in dogs following bilateral tibial tuberosity advancement (TTA), between tibiae treated with and without autogenous cancellous bone grafts. METHODS: Ten dogs with bilateral cranial cruciate ligament disease requiring surgical stabilisation were prospectively recruited to undergo single-session bilateral TTA, with only one, randomly assigned, tibia receiving bone graft in the osteotomy deficit. Bone healing at the osteotomy site was assessed using CT performed 38-70 days post-operatively. CT images were evaluated using both objective measurements of osseous bridging and subjective evaluation by six radiologists. Repeated measures ANOVA was used to compare the objective outcomes between the grafted and non-grafted tibiae. RESULTS: The mean percentage of the osteotomy deficit bridged at the lateral cortex was greater in grafted (77.6, SD 35.2%) compared to non-grafted (63.0, SD 36.5%) tibiae (p=0.001), but did not differ at the medial cortex (p=0.1). The mean minimum callus width was greater in grafted (7.2, SD 3.3 mm) compared to non-grafted (3.6, SD 2.9 mm) tibiae (p<0.001). There was no difference in mean attenuation (measured in Hounsfield units) of the callus between grafted and non-grafted tibiae (p=0.5). The grafted tibia was deemed to have superior bone healing in 50/60 subjective assessments made by radiologists. CONCLUSIONS: Superior osseous bridging was detected by CT analysis following TTA using autogenous cancellous bone grafts compared with no graft. This was shown by greater bridging percentage at the lateral cortex and formation of a broader callus. Qualitative assessments made by six radiologists also supported the conclusion that bone healing was improved by use of autogenous cancellous bone graft. CT was a useful method for assessing evidence of bone healing following TTA. CLINICAL RELEVANCE: These findings justify the application of autogenous cancellous bone graft to augment healing following TTA in dogs.

Negative pressure wound therapy using a portable single-use device for free skin grafts on the distal extremity in seven dogs.

OBJECTIVE: Retrospective study to describe clinical experience with a portable single-use negative pressure wound therapy device after application of full-thickness meshed skin grafts to wounds on the distal extremities of seven dogs. METHODS: Seven dogs were treated with portable NPWT after receiving skin grafts; six as the result of tumour resection and one for traumatic injury. Medical records were reviewed and data recorded on patient signalment, cause and location of wound, surgical technique, application and maintenance of portable NPWT, graft survival and outcome, and complications encountered with the system. CLINICAL OUTCOMES: NPWT was provided for between 4 and 7 days. Five patients were discharged from hospital during the treatment period. Application and maintenance of the portable device was technically easy and no major complications were encountered. Minor complications consisted of fluid accumulation in the evacuation tubing. All dogs achieved 100% graft survival. CONCLUSIONS: Application and maintenance of the portable device was technically straightforward. All dogs receiving portable NPWT after transfer of a free skin graft to the distal extremity had a successful outcome.

Major complications and risk factors associated with surgical correction of congenital medial patellar luxation in 124 dogs.

Dogs treated for congenital medial patellar luxation were reviewed for the purpose of determining the incidence of postoperative major complications requiring surgical revision and the risk factors for their occurrence. Major complications occurred in 18.5% of the patellar luxation stabilization procedures with implant associated complications being the most frequent, patellar reluxation the second, and tibial tuberosity avulsion the third most common major complication. Other complications included patellar ligament rupture and trochlear wedge displacement. When recession trochleoplasty was performed in addition to tibial tuberosity transposition, a 5.1-fold reduction in the rate of patellar reluxation was observed. Release of the cranial belly of the sartorius muscle further reduced the incidence of patellar reluxation, while patella alta (pre- or postoperative) and patellar luxation grade were not found to influence the rate of reluxation. Tibial tuberosity avulsion was 11.1-times more likely when using a single Kirschner wire to stabilize a transposition, compared with two Kirschner wires. Independent to the number of Kirschner wires used, the more caudodistally the Kirschner wires were directed, the higher the risk for tibial tuberosity avulsion. Tension bands were used in 24.4% of the transpositions with no tuberosity avulsion occurring in stifles stabilized with a tension band. Overall, grade 1 luxations had a significantly lower incidence of major complications than other grades, while body weight, age, sex, and bilateral patellar stabilization were not associated with risk of major complication development.

Inter- and intra-operator variability associated with extracapsular suture tensioning: an ex vivo study.

OBJECTIVES: To determine inter- and intra- operator variability associated with extracapsular suture tensioning as performed during lateral fabello-tibial suture placement. STUDY DESIGN: Ex vivo study. METHODS: Fifteen Greyhound cadaveric pelvic limbs were prepared by cutting the cranial cruciate ligament and placing an extracapsular fabello-tibial suture. On two occasions, three surgeons tensioned the extracapsular suture of each stifle. Stifles were returned to 135 degrees of flexion and the suture tension was measured using a commercially available suture tensioner with inbuilt tensiometer. STATISTICAL ANALYSIS: Intra-operator and inter-operator agreement were assessed using the limits of agreement method. A linear mixed effects model was specified to assess the effect of operator, repeated estimates and stifle order on tension applied. RESULTS: The mean difference within the three operators ranged from 0 to 14.7N. With 95% limits of agreement, on most occasions for all three operators, the difference was between -31.7 and 41.0 N. The mean difference between the three operators ranged from 6.0 to 30.7 N. With 95% limits of agreement, on most occasions the difference between operators was between -25.6 and 62.5 N. CLINICAL SIGNIFICANCE: Marked variation exists in the tension applied during fabello-tibial suture application, both within and between surgeons. This variation may lead to inconsistent clinical outcomes. Further studies are required to determine the clinical consequences of this marked variation in extracapsular suture tensioning.

Evidence-based evaluation of the risks of malignancy predicted by thyroid fine-needle aspiration biopsies.

A National Cancer Institute (NCI) "Thyroid Fine-Needle Aspiration (FNA) State of the Science Conference" recently proposed standardized nomenclature and "risks of malignancies" associated with various diagnostic categories. We evaluated the evidence levels of the data used by NCI to predict malignancy risks and whether those estimates had clinical validity in our patient population.Eight hundred seventy-nine patients underwent thyroid FNA during 2006. FNA diagnoses were translated into NCI diagnostic categories, and 2-year follow-up retrospective information was obtained. Four percentages of malignancies were calculated for each diagnostic category using follow-up information from FNA, thyroidectomy, both, and all patients as denominators. 95% confidence intervals (CI) were estimated for all proportions, and results were analyzed with chi-square statistics. "Relative risk" calculations were performed using the percentage of malignancies in the entire population under study as a denominator.Most of the studies cited by the NCI provided incomplete and variable level III evidence based mainly on surgical follow-up. Among our patients, the percentages of malignancies calculated with follow-up data from all patients as the denominator were similar to the "risk estimates" proposed by the NCI, but estimates based on surgical follow-up overestimated the probability of thyroid malignancy for patients with FNA diagnosis of "benign" and "follicular lesions of undetermined significance" (FLUS). Relative risk and 95% CI calculations suggested that the NCI classification could be simplified into three categories: "benign," "FLUS + neoplasm," and "suspicious + malignant."

Hiatal hernia controversies--a review of pathophysiology and treatment options.

OBJECTIVE: To provide a detailed discussion of the aetiology and pathophysiology of hiatal hernia in both humans and small animals, and review current medical and surgical treatments. DESIGN: Review article. SUMMARY: Hiatal hernia is not completely understood in humans or animals. It has a complex multifactorial aetiology and pathophysiology. A primary disturbance of the lower oesophageal sphincter has not been shown in humans or animals. Knowledge of pathophysiology is necessary to institute appropriate treatment. Medical and/or surgical therapy is not indicated in asymptomatic cases. Medical treatment should be used for up to 1 month in stable cases of sliding hiatal hernia. Paraoesophageal hiatal hernias and any large sliding hiatal hernia should be considered for prompt surgical treatment. Surgical techniques used depend on the type of hiatal hernia present. Surgical treatment of hiatal hernia cases should be performed by experienced surgeons, and must include hiatal closure and gastropexy. The Nissen fundoplication procedure has been discontinued in the veterinary field due to poor success rates, coupled with the published view that there is a marked difference in pathophysiology between humans and dogs. Reported complications associated with the original Nissen fundoplication technique are identical in the human and veterinary literature. There have been no complications reported with use of the modified or 'floppy' Nissen fundoplication in dogs. Both oesophagopexy and Nissen fundoplication require further evaluation in small animals.

Morphometry confirms the presence of considerable nuclear size overlap between "small cells" and "large cells" in high-grade pulmonary neuroendocrine neoplasms.

We morphometrically evaluated 5-micron H&E-stained sections from 28 surgically resected high-grade pulmonary neuroendocrine neoplasms, including 16 small cell lung carcinomas (SCLCs) and 12 large cell neuroendocrine carcinomas (LCNECs). For each case, 200 tumor nuclei and 20 to 100 normal lymphocytes were measured. The frequency distributions of tumor cell/lymphocyte (TC/L) size ratios were plotted in bins ranging from 1 to 6, classified into 6 histogram types with TC/L size ratio peaks ranging from 2 to 6 (A-E) and a histogram with a wide distribution (F). SCLCs fit histograms A through E; LCNECs, A through F. Morphometry demonstrated considerable nuclear size overlap in high-grade neoplasms. Approximately one third of SCLCs exhibited considerable numbers of neoplastic cells that were larger than 3 normal lymphocytes, while 4 of 12 LCNECs had a predominant number of small cells. Ten tumors exhibited a B histogram with a "borderline" peak TC/L of 3. The rule that a TC/L size ratio larger than 3 helps distinguish "large" from "small" neoplastic cells was confirmed in only 9 of 28 cases. The use of more generic terminology such as "high-grade neuroendocrine carcinoma" or "grade III neuroendocrine carcinoma" for SCLC and LCNEC is discussed.

Pancreatic pseudocyst causing extrahepatic biliary obstruction in a dog.

A 3-year-old Rhodesian Ridgeback was examined because of recurrent pancreatitis of 2 months duration. The dog had signs of abdominal pain and jaundice. Blood biochemical findings were consistent with extrahepatic bile duct obstruction, but on abdominal ultrasonography no cause of obstruction was identified. At surgery a pancreatic pseudocyst was found in the body of the pancreas. Cystoduodenostomy, cystic omentalization and biliary diversion resulted in excellent long-term recovery.

"Virtual microscopy" and the internet as telepathology consultation tools: diagnostic accuracy in evaluating melanocytic skin lesions.

The Internet offers a widely available, inexpensive tool for telepathology consultations. It allows the transfer of image and text files through electronic mail (e-mail) or file transfer protocols (FTP), using a variety of microcomputer platforms. We studied the use of the Internet and "virtual microscopy" tools for the diagnosis of 35 skin biopsies, including a variety of benign and malignant melanocytic lesions. Digitized images from these lesions were obtained at 40x and 100x optical magnification, using a high resolution digital camera (Microlumina, Leaf Systems, Southborough, MA), a light microscope with a phototube adapter and a microcomputer with a Pentium 166 MHz microprocessor. Two to four images of each case were arranged on a "canvas" to represent the majority or an entire biopsy level, using Photoshop software (Adobe Systems Inc., San Jose, CA). The images were compressed using Joint Photographers Expert Group (JPEG) format. The images were then viewed on a computer video monitor in a manner that closely resembles light microscopy, including scrolling by using the "hand tool" of Photoshop and changing magnification digitally up to 4 times without visible image degradation. The image files, ranging in size from 700 kilobytes to 2.1 megabytes (average 1.6 megabytes) were attached to e-mail messages that contained clinical information, using standard Multipurpose Internet Mail Extension (MIME) protocols and sent through the Internet, for interpretation by a dermatopathologist. The consultant could open the images from the e-mail message, using Microsoft Outlook Express (Microsoft Corp., Redmond, WA) and Photoshop software, scroll them, change magnification and render a diagnosis in a manner that closely simulates light microscopy. One hundred percent concordance was obtained between the telepathology and traditional hematoxylin and eosin slide diagnoses. The Internet and relatively inexpensive "virtual microscopy" tools offer a novel technology for dermatopathology consultations. Potential applications of this technology to pathology and technical problems posed by the use of an open, widely distributed network to share sensitive medical information are discussed.

Lung allograft dysfunction correlates with gamma-interferon gene expression in bronchoalveolar lavage.

BACKGROUND: Preceding episodes of acute cellular rejection (ACR) may predispose lung allografts to the subsequent development of irreversible dysfunction or bronchiolitis obliterans syndrome (BOS). Other histologic patterns such as bronchiolitis obliterans with organizing pneumonia (BOOP), organizing pneumonia, lymphocytic bronchiolitis and diffuse alveolar damage (DAD) may also adversely affect allograft function. We have previously reported the predominant expression of Th1 cytokines (IL-2 and interferon gamma) in rejecting and Th2 (IL-10) in a tolerant model of rat lung transplantation. Here we correlate the "Th1/Th2 paradigm" in clinical lung transplantation with histologic findings and assess the effect on serial spirometric function. METHODS: We examined the mRNA expression of IL-2, interferon gamma, IL-10 and ICAM-1 in 53 bronchoalveolar lavage (BAL) specimens from 23 lung transplant (LT) recipients utilizing qualitative "nested" reverse transcriptase polymerase chain reaction (RT-PCR). We also measured IgG1 and IgG2 levels in 44 BAL specimens by ELISA. The mRNA expression for cytokines, ICAM-1 and the IgG2/IgG1 ratios were correlated with the presence or absence of ACR and alternate "histologic patterns". Serial spirometry were analyzed for the 2-3 month interval before bronchoscopic (FOB) assessment to derive "baseline" forced expiratory volume-one second (FEV1) values. The change in FEV1 coincident with (deltaFEV1 pre) and for the 2-3 month interval subsequent to (deltaFEV1 post) FOB were expressed relative to "baseline" spirometric indexes. RESULTS: Detection of mRNA for interferon gamma and ICAM-1 correlated significantly with ACR, whereas IL-2 and IL-10 expression did not correlate. IL-10 was virtually "ubiquitous" in most BAL samples irrespective of the presence or absence of ACR. The highest correlation was observed with interferon gamma for acute cellular rejection whereupon the sensitivity was 77.7%, specificity 87.7%, positive predictive value 73.6% and negative predictive value 88.2%, although for ICAM-1 these values were 75%, 65.7%, 50.0% and 85.0%, respectively. Nevertheless, 4 of 5 episodes of respiratory tract infection (bacterial, CMV, Aspergillus spp.) were similarly associated with cytokine mRNA. The ratios of IgG2 to IgG1, a reflection of Th1/Th2 influence, were not statistically different when analyzed for the presence or absence of ACR (0.91+/-0.53 vs. 1.02+/-0.70, respectively; p = NS). By analysis of FEV1 trends, expression of interferon gamma was associated with a greater and persistent decrement (deltaFEV1 pre: -0.265+/-0.78 liters, and post: -0.236+/-0.1161; mean +/- SE) than ACR in the absence of interferon gamma expression (+0.158 +/- +0.065 and +0.236+/-0.007 liters, respectively) (Student-Newman-Keuls, p<.05). CONCLUSION: Our findings suggest that interferon gamma mRNA expression and ICAM-1 may be valuable in both the diagnosis and prognosis for lung allograft ACR. IL-10, a Th2 cytokine, was locally expressed both in the presence and absence of ACR. Expression of mRNA for interferon y in BAL and, to a lesser extent ICAM-1, were associated with increased lung allograft dysfunction. Whether BAL cytokine "immunosurveillance" would complement or possibly supplant a specific "histologic pattern" and thereby direct different therapies after lung transplantation, may be potentially rewarding areas of further investigation.

Mediastinal tumors of peripheral nervous system origin.

A wide spectrum of benign and malignant tumors of peripheral nervous system origin can arise in the mediastinum. These neoplasms are more frequent in the posterior mediastinum and can develop from peripheral nerves, sympathetic and parasympathetic ganglia, and neural tube embryonic remnants. The clinicopathologic features of mediastinal schwannomas, melanotic schwannomas, neurofibromas, ganglioneuromas, granular cell tumors, malignant tumors of peripheral nerve sheath origin, malignant melanocytic tumors of peripheral nerve sheath origin, neuroblastomas, ganglioneuroblastomas, and pigmented neuroectodermal tumors of infancy are reviewed.

Reasoning with uncertainty in pathology: artificial neural networks and logistic regression as tools for prediction of lymph node status in breast cancer patients.

Axillary lymph node status is an important prognostic feature for patients with breast cancer, but the therapeutic value of axillary lymphadenectomy is controversial. It would be useful to be able to predict the status of axillary lymph nodes before lymphadenectomy from prognostic features evaluated in a previous breast biopsy. This prediction would be useful to optimize the treatment of patients with breast cancer who are unlikely to have nodal metastases. We studied 279 patients with invasive breast carcinoma treated with modified radical mastectomy or with lumpectomy combined with axillary lymph node dissection. Prognostic factors evaluated were age, histologic type of invasive tumor, presence of associated ductal and/or lobular carcinoma in situ, lesion size, histologic and nuclear grades, DNA index, presence of multiploidy by flow cytometric analysis, and immunocytochemical expression of estrogen and progesterone receptors, proliferating nuclear cell antigen, and HER-2/neu oncogene. Several probabilistic neural networks (NNs) with genetic algorithms were developed using prognostic features as input neurons and lymph node status (positive or negative) as output neurons. The data were also studied with multiple regression and logistic regression analysis. The best NN model trained with 224 cases using 19 input neurons. It classified correctly 49 (89.0%) of 55 unknown cases (specificity, 97.2%; sensitivity, 80.0%; positive predictive value, 93.8%; negative predictive value, 87.5%). Several statistically significant models could be fitted with both multiple regression and logistic regression. The logistic regression model fitted with 240 cases using 6 independent variables estimated correctly 26 (66%) of 39 holdout cases. NNs and logistic regression models offer potentially useful tools to estimate the status of axillary lymph nodes of breast cancer patients before axillary lymphadenectomy. Future prospective studies with larger groups of patients and perhaps better prognostic markers are needed before these predictive multivariate models become ready for clinical use.

Disc extrusion in a Rottweiler dog with caudal cervical spondylomyelopathy after failure of intervertebral distraction/stabilisation.

A Rottweiler dog was presented with an 8 week history of hindlimb ataxia. Neurological examination localised the lesion to the cervical spinal cord. Myelography demonstrated dynamic compressive lesions at C5-6 and C6-7 consistent with a diagnosis of caudal cervical spondylomyelopathy. Distraction/stabilisation of both discs was performed using interbody polymethyl methacrylate. Both implants subsequently failed leading to extrusion of the remaining dorsal annulus fibrosus of the C5-6 intervertebral disc and nonambulatory tetraparesis. A ventral slot combined with distraction/stabilisation using screws and polymethyl methacrylate was performed and resulted in nearly full neurological recovery.

Virtual microscopy and the Internet as telepathology consultation tools. A study of gastrointestinal biopsy specimens.

Telepathology (TP) is the practice of pathology at a distance using videomicroscopy and telecommunication tools. We explore the use of "virtual microscopy" techniques and the Internet as tools for TP gastrointestinal biopsy consultations. Thirty-five gastrointestinal biopsy specimens were photographed in Los Angeles by using a high-resolution digital camera, a light microscope, and a Pentium 166 microcomputer. Several (2-8) digital photomicrographs were collected at 40x or 100x optical magnification, using 2,700 x 3,400 pixel resolution. The photomicrographs illustrated all the tissue fragments present in 1 of the biopsy levels. They were saved in medium compression JPEG image format. These images can be magnified digitally up to 600% without visible degradation and scrolled at different magnifications on a video monitor, simulating examination under a light microscope. The images files (281 to 3,324 KB) were attached to e-mail messages containing patient information and sent through the Internet to Michigan for interpretation using a Power Macintosh 7100 system. The e-mail process was successful in 100% of instances; 2 files were corrupted owing to user error and had to be resent. Additional photos were requested in 1 case. In 33 of 35 cases, there was diagnostic concordance between the original and the TP diagnoses. The 2 discrepancies were due to diagnostic disagreement. This technology offers pathologists relatively inexpensive and effective tools for gastrointestinal TP consultations.

Bacterial septic arthritis in 19 dogs.

OBJECTIVE: To provide information on the clinical features, diagnosis and treatment of bacterial septic arthritis in dogs. DESIGN: A retrospective study examining case records of all dogs diagnosed with bacterial septic arthritis at Murdoch University Veterinary Hospital between 1988 and 1997. RESULTS: Nineteen dogs were diagnosed with bacterial septic arthritis, which most commonly occurred after surgery involving the stifle joint. Haematogenous infection occurred in only five dogs. Diagnosis was based on clinical signs, joint fluid analysis, radiography, microbiology and/or response to treatment. Chronic lameness was the most common problem at presentation. Analysis of joint fluid invariably revealed large number of nucleated cells, which consisted primarily of neutrophils. In all but one case the neutrophils were nondegenerate. Culture of joint fluid was frequently successful. Staphylococcus spp were the most common bacteria isolated. Treatment involved antimicrobial drugs only in five dogs. Other dogs received antimicrobial drugs in combination with surgical procedures such as joint lavage and removal of nonabsorbable suture material (eight), arthrodesis (two) or amputation (one). Two dogs were euthanased. Most dogs responded well to treatment and were free of signs of septic arthritis at follow-up. CONCLUSION: Bacterial septic arthritis may often be mild and manifest as chronic lameness. Analysis of joint fluid will detect an inflammatory arthropathy but the presence of toxic neutrophils should not be relied on as an indicator of sepsis. Culture of infected joint fluid is likely to be successful if antimicrobials are not given prior to collection and if the sample is inoculated into enrichment broth. Treatment should involve antimicrobial drugs, open-joint lavage and removal of joint prostheses if the infection is associated with previous surgery.

Virtual microscopy: high resolution digital photomicrography as a tool for light microscopy simulation.

Recent advances in microcomputers and high resolution digital video cameras provide pathologists the opportunity to combine precision optics with digital imaging technology and develop new educational and research tools. We review recent advances in virtual microscopy and describe techniques for viewing digital images using a microcomputer-based workstation to simulate light microscopic examination, including scanning at low power to select features of interest and zooming to increase magnification. Hardware and software components necessary to acquire digital images of histological and cytological slides, and closely simulate their examination under a light microscope are discussed. The workstation is composed of a MicroLumina digital scanning camera (Leaf Systems, Southborough, MA), light microscope (Olympus Optical Co., Lake Success, NY), Pentium (Intel Corp., Santa Clara, CA) 166 MHz microcomputer configured with 64 megabytes of random access memory (RAM), a MGA Millenium Powerdesk graphics card (Matrox Graphics, Inc., Montreal, Canada) and Photoshop software (Adobe Systems Inc., San Jose, CA) running in a Windows 95 (Microsoft Corp., Redmond, WA) environment. Images with spatial resolutions of up to 2700 x 3400 pixels in 36-bit color, can be displayed simultaneously as distinct images in a montage, or merged into a single composite image file to highlight significant features of a histological or cytological slide. These image files are saved in Joint Photographers Experts Group (JPEG) format using compression ratios of up to 80:1 without detectable visual degradation. The advantages and technical limitations of various workstation components are addressed and applications of this technology for pathology education, proficiency testing, telepathology, and database development are discussed.

Antithrombin III treatment improves parameters of acute inflammation in a highly histoincompatible model of rat lung allograft rejection.

BACKGROUND: Antithrombin III (AT-III) is an antithrombotic agent with known anti-inflammatory properties that is also known to attenuate acute inflammation, prevent ischemia-reperfusion injury, and disseminated intravascular coagulation (DIC) associated with sepsis and endotoxemia. Here, we examined the ability of AT-III to modify parameters of acute inflammation in a highly histoincompatible model of rat lung allograft rejection (AR). METHODS: After left single lung transplantations (BN-->Lew), recipient animals were treated i.v. with 50 U/kg of human AT-III (low dose group), 500 U/kg of human AT-III (high dose group), or normal saline (control group) on days 2 and 4 posttransplant. All animals were sacrificed on day 6, and several pathological categories of acute inflammation related to AR were scored (0-4). The effect of AT-III on concanavalin A (Con A)-stimulated rat spleen cell proliferation was also examined. RESULTS: The stage of AR, and the degrees of edema, hemorrhage, and necrosis were significantly reduced in the high dose group compared with the control group. AT-III significantly inhibited rat spleen cell proliferation in response to Con A, in a dose-dependent manner. Maximal inhibition was seen at 15 U/ml in culture. Identical inhibition of Con-A-stimulated cultures occurred in both serum free and serum-containing media, indicating that AT-III inhibition of Con-A-stimulated rat spleen cell proliferation is independent of its actions on thrombin. CONCLUSIONS: 1) AT-III treatment significantly improves parameters of acute inflammation seen in a highly histoincompatible model of rat lung AR. 2) AT-III inhibits in vitro T cell proliferation to the potent mitogen Con A, suggesting that protease inhibition may inhibit T cell activation in vitro. 3). The beneficial effects of AT-III on parameters of lung AR relate to the anti-coagulant, anti-inflammatory, and possibly immunoregulatory actions of AT-III.

Virtual microscopy and public-key cryptography for Internet telepathology.

The Internet is a potentially inexpensive, widely available medium for telepathology, but there are concerns about its reliability and security. Using a digital camera, 41 photomicrographs of transbronchial biopsies, at x 100 optical magnification, were captured and digitized at 2700 x 3400 pixel, 24 bit/pixel resolution. The image files were saved in JPEG format at medium compression, attached to text files with patient information, encrypted for security in the S/MIME format using a digital signature and digital envelope, and transmitted by email. Received email files were decrypted automatically and the images viewed with standard software. Telepathology diagnoses were compared with original interpretations. The images averaged 810 kByte in size. The encryption and decryption did not cause significant delays in overall transmission time and, together with transmission, did not produce noticeable image degradation. The received image files could be viewed in a manner that simulated light microscopy. There was agreement between telepathology and original diagnoses in 92% of the cases. All the discrepancies were due to inadequate area selection because the pathological features of interest were present in histological levels other than those photographed. The use of high-resolution digital photomicrography, the Internet and public-key cryptography offers an effective and relatively inexpensive method of telepathology consultation. The method is best suited for the diagnosis of small biopsy specimens that require the transmission of only a few digital images that represent the majority of the biopsy materials.

Pre-transplant donor-specific transfusions induce allograft rejection and IL-2 gene expression in the WKY-->F344 functional tolerance model of rat lung transplantation.

Our previous studies have shown that a spontaneous functional tolerance develops in a rat model of lung transplantation (WKY-->F344). The tolerance observed in this model may be due to the minor histocompatible differences in this combination, however, the possibility of a tolerogenic effect related specifically to the lung allograft must be considered. To further examine this model, the effect of pre-transplant donor-specific spleen cell transfusions (DSTs) was examined on the functional tolerance state seen in this model. F344 rats received WKY spleen cells on days -45 and -30 before lung transplantations. Control F344 rats received lung transplants without DSTs. Recipients in both groups were killed on day 7, 14, 21 and 49 post-transplant, and allograft rejection (AR) was graded histologically (stage 0-IV). Intragraft cytokine gene transcripts were examined on day 7 and 14 post-transplant using reverse transcriptase-polymerase chain reaction (RT-PCR) techniques to investigate the underlying immunological events occurring in each group. In addition, allogeneic (WKY) and third party (BN) skin grafts were placed on lung recipients at day 35 post-transplant to evaluate the development of systemic tolerance. It was seen that control animals showed moderate to severe lymphocytic infiltrations (stage II-III AR) in the first 3 weeks followed by spontaneous recovery with stage I-II AR on day 49. In marked contrast, DST-treated animals showed more aggressive AR with severe lymphocytic infiltration and haemorrhagic infarction (stage III-IV AR) by day 14-21, without any evidence of recovery on day 49. WKY skin grafts showed prolonged survival in control animals, but were promptly rejected in DST-treated animals. Intragraft cytokine gene expression in control animals was characterized by no or weak expression of IL-2 and high IL-10, while DST-treated animals showed high levels of IL-2 transcripts. IL-2:IL-10 and IL-2:IL-4 ratios were significantly increased in DST-treated animals compared with controls on day 7 post-transplant. It was concluded that pre-transplant DSTs did not enhance allograft survival, but actually induced AR and ablated any immunological benefit of the lung allograft on induction of tolerance in the WKY-->F344 lung transplant model. It was found that the DST-induced AR was associated with a deviation of cytokine immune responses from a predominant Th2 to Th1 profile characterized by increased IL-2 gene expression in the allografts. We also conclude that factors other than the degree of histocompatibility matching, such as the route and timing of alloantigen exposure, and the amount or nature of alloantigens associated specifically with lung allografts, are involved in deviating native immune responses toward acceptance or rejection of lung allografts in this model of lung transplantation.