mRNA therapy restores euglycemia and prevents liver tumors in murine model of glycogen storage disease

Glycogen Storage Disease 1a (GSD1a) is a rare, inherited metabolic disorder caused by deficiency of glucose 6-phosphatase (G6Pase-α). G6Pase-α is critical for maintaining interprandial euglycemia. GSD1a patients exhibit life-threatening hypoglycemia and long-term liver complications including hepatocellular adenomas (HCAs) and carcinomas (HCCs). There is no treatment for GSD1a and the current standard-of-care for managing hypoglycemia (Glycosade®/modified cornstarch) fails to prevent HCA/HCC risk. Therapeutic modalities such as enzyme replacement therapy and gene therapy are not ideal options for patients due to challenges in drug-delivery, efficacy, and safety. To develop a new treatment for GSD1a capable of addressing both the life-threatening hypoglycemia and HCA/HCC risk, we encapsulated engineered mRNAs encoding human G6Pase-α in lipid nanoparticles. We demonstrate the efficacy and safety of our approach in a preclinical murine model that phenotypically resembles the human condition, thus presenting a potential therapy that could have a significant therapeutic impact on the treatment of GSD1a.

Nonclinical comparability studies of recombinant human arylsulfatase A addressing manufacturing process changes

Recombinant human arylsulfatase A (rhASA) is in clinical development for the treatment of patients with metachromatic leukodystrophy (MLD). Manufacturing process changes were introduced to improve robustness and efficiency, resulting in higher levels of mannose-6-phosphate and sialic acid in post-change (process B) compared with pre-change (process A) rhASA. A nonclinical comparability program was conducted to compare process A and process B rhASA. All doses were administered intrathecally. Pharmacodynamic comparability was evaluated in immunotolerant MLD mice, using immunohistochemical staining of lysosomal-associated membrane protein-1 (LAMP-1). Pharmacokinetic comparability was assessed in juvenile cynomolgus monkeys dosed once with 6.0 mg (equivalent to 100 mg/kg of brain weight) process A or process B rhASA. Biodistribution was compared by quantitative whole-body autoradiography in rats. Potential toxicity of process B rhASA was evaluated by repeated rhASA administration at doses of 18.6 mg in juvenile cynomolgus monkeys. The specific activities for process A and process B rhASA were 89 U/mg and 106 U/mg, respectively, which were both well within the target range for the assay. Pharmacodynamic assessments showed no statistically significant differences in LAMP-1 immunohistochemical staining in the spinal cord and in most of the brain areas assessed between process A and B rhASA-dosed mice. LAMP-1 staining was reduced with both process A and B rhASA compared with vehicle, supporting its activity. Concentration–time curves in cerebrospinal fluid and serum of cynomolgus monkeys were similar with process A and B rhASA. Process A and B rhASA were similar in terms of their pharmacokinetic parameters and biodistribution data. No process B rhASA-related toxicity was detected. In conclusion, manufacturing process changes did not affect the pharmacodynamic, pharmacokinetic or safety profiles of process B rhASA relative to process A rhASA.

Ludwig's Angina: Report of a Case and Review of Management Issues

Ludwig's angina, although uncommon, remains a potentially life-threatening condition because of the risk of impending airway obstruction. Effective treatment is based on early recognition of the clinical process, with the appropriate use of parenteral antibiotics, airway protection techniques, and formal surgical drainage of the infection. We present a case of Ludwig's angina together with a brief review of the relevant literature.

A Comprehensive Map of CNS Transduction by Eight Recombinant Adeno-associated Virus Serotypes Upon Cerebrospinal Fluid Administration in Pigs

Cerebrospinal fluid administration of recombinant adeno-associated viral (rAAV) vectors has been demonstrated to be effective in delivering therapeutic genes to the central nervous system (CNS) in different disease animal models. However, a quantitative and qualitative analysis of transduction patterns of the most promising rAAV serotypes for brain targeting in large animal models is missing. Here, we characterize distribution, transduction efficiency, and cellular targeting of rAAV serotypes 1, 2, 5, 7, 9, rh.10, rh.39, and rh.43 delivered into the cisterna magna of wild-type pigs. rAAV9 showed the highest transduction efficiency and the widest distribution capability among the vectors tested. Moreover, rAAV9 robustly transduced both glia and neurons, including the motor neurons of the spinal cord. Relevant cell transduction specificity of the glia was observed after rAAV1 and rAAV7 delivery. rAAV7 also displayed a specific tropism to Purkinje cells. Evaluation of biochemical and hematological markers suggested that all rAAV serotypes tested were well tolerated. This study provides a comprehensive CNS transduction map in a useful preclinical large animal model enabling the selection of potentially clinically transferable rAAV serotypes based on disease specificity. Therefore, our data are instrumental for the clinical evaluation of these rAAV vectors in human neurodegenerative diseases.

Sustained Systemic Glucocerebrosidase Inhibition Induces Brain α-Synuclein Aggregation, Microglia and Complement C1q Activation in Mice

AIMS

Loss-of-function mutations in GBA1, which cause the autosomal recessive lysosomal storage disease, Gaucher disease (GD), are also a key genetic risk factor for the α-synucleinopathies, including Parkinson's disease (PD) and dementia with Lewy bodies. GBA1 encodes for the lysosomal hydrolase glucocerebrosidase and reductions in this enzyme result in the accumulation of the glycolipid substrates glucosylceramide and glucosylsphingosine. Deficits in autophagy and lysosomal degradation pathways likely contribute to the pathological accumulation of α-synuclein in PD. In this report we used conduritol-β-epoxide (CBE), a potent selective irreversible competitive inhibitor of glucocerebrosidase, to model reduced glucocerebrosidase activity in vivo, and tested whether sustained glucocerebrosidase inhibition in mice could induce neuropathological abnormalities including α-synucleinopathy, and neurodegeneration.

RESULTS

Our data demonstrate that daily systemic CBE treatment over 28 days caused accumulation of insoluble α-synuclein aggregates in the substantia nigra, and altered levels of proteins involved in the autophagy lysosomal system. These neuropathological changes were paralleled by widespread neuroinflammation, upregulation of complement C1q, abnormalities in synaptic, axonal transport and cytoskeletal proteins, and neurodegeneration.

INNOVATION

A reduction in brain GCase activity has been linked to sporadic PD and normal aging, and may contribute to the susceptibility of vulnerable neurons to degeneration. This report demonstrates that systemic reduction of GCase activity using chemical inhibition, leads to neuropathological changes in the brain reminiscent of α-synucleinopathy.

CONCLUSIONS

These data reveal a link between reduced glucocerebrosidase and the development of α-synucleinopathy and pathophysiological abnormalities in mice, and support the development of GCase therapeutics to reduce α-synucleinopathy in PD and related disorders.

Telepathology overview: from concept to implementation

Telepathology is the practice of pathology at a distance by using video imaging and telecommunications. Significant progress has been made in telepathology. To date, 12 classes of telepathology systems have been engineered. Rapid and ultrarapid virtual slide processors may further expand the range of telepathology applications. Next-generation digital imaging light microscopes, such as miniaturized microscope arrays (MMA), may make virtual slide processing a routine laboratory tool. Diagnostic accuracy of telepathology is comparable with that of conventional light microscopy for most diagnoses. Current telepathology applications include intraoperative frozen sections services, routine surgical pathology services, second opinions, and subspecialty consultations. Three telepathology practice models are discussed: the subspecialty practice (SSP) model; the case triage practice (CTP) model; and the virtual group practice (VGP) model. Human factors influence performance with telepathology. Experience with 500 telepathology cases from multiple organs significantly reduces the video viewing time per case (P < .01). Many technology innovations can be represented as S-curves. After long incubation periods, technology use and/or efficiency may accelerate. Telepathology appears to be following an S-curve for a technical innovation.

The lower limb in people with diabetes. Position statement of the Australian Diabetes Society

Diabetic lower-limb problems result in significant social, medical and economic consequences and are the most common cause of hospitalisation for people with diabetes. In people with diabetes, amputations are 15 times more common than in people without diabetes, and 50% of all amputations occur in people with diabetes. Peripheral neuropathy, vascular disease, infection and deformity of the feet are the major predisposing factors leading to ulceration or amputation. All people with diabetes should receive basic footcare education, and regular foot examinations. The risk for the development of ulceration can be assessed by basic clinical examination of the foot. Management strategies depend on the risk category, and range from basic education and annual review to specialist care by a multidisciplinary team.

Case triage model for the practice of telepathology

OBJECTIVE

To implement and evaluate a practice model for telepathology.

METHODS

A case triage practice model was devised in which general pathologists review all cases and refer them to subspecialists only when necessary. In 1993, the Arizona-International Telemedicine Network (AITN), a high-resolution static imaging telepathology diagnostic network, linking six sites to the University of Arizona in Tucson, began testing the model. Work flow through the network was analyzed, and diagnostic concordance was assessed in 150 surgical cases by comparing the diagnoses of the referring (transmitting) pathologists with diagnoses of the consulting (receiving) telepathologists as well as by comparing the referring pathologists' diagnoses with the consensus diagnoses reached by an independent review panel. Data analysis was controlled for subspecialty case type. Telepathologists had access to the referring pathologists' preliminary diagnoses, and the review panel had access to the original glass slides and the surgical pathology reports prior to rendering their respective diagnoses.

RESULTS

The triage pathologist completed the telepathology consultation without the assistance of a subspecialty pathologist in 66% of the cases. The review panel examined the original glass slides from 134 cases by light microscopy. Concordance rates of the telepathologists' or review panel's diagnoses with the referring pathologists' diagnoses were not statistically different (93.1% v 83.6%, respectively; P > 0.05).

CONCLUSION

The case triage model is suitable for the practice of telepathology. It significantly reduces the need for subspecialty pathologists. Static imaging telepathology is useful and reasonably efficient for rendering diagnostic opinions in the majority of referred cases. Tissue sampling limitations imposed by static imaging occasionally resulted in diagnostic errors.

Dynamic-robotic telepathology: Department of Veterans Affairs feasibility study

In this retrospective study, we assess the accuracy, confidence levels, and viewing times of two generalist pathologists using both dynamic-robotic telepathology and conventional light microscopy (LM) to render diagnoses on a test set of 100 consecutive routine surgical pathology cases. The objective is to determine whether telepathology will allow a pathology group practice at a diagnostic hub to provide routine diagnostic services to a remote hospital without an on-site pathologist. For TP, glass slides were placed on the motorized stage of the robotic microscope of a telepathology system by a senior laboratory technologist in Iron Mountain, MI. Real-time control of the motorized microscope was then transferred to a pathologist in Milwaukee, WI, who viewed images of the glass slides on a video monitor. The telepathologists deferred rendering a diagnosis in 1.5% of cases. Clinically important concordance between the individual diagnoses rendered by telepathology and the "truth" diagnoses established by rereview of glass slides was 98.5%. In the telepathology mode, there were five incorrect diagnoses out of a total of 197 diagnoses. In four cases in which the telepathology diagnosis was incorrect, the pathologist's diagnosis by LM was identical to that rendered by telepathology. These represent errors of interpretation and cannot be ascribed to telepathology. The certainty of the pathologists with respect to their diagnoses was evaluated over time. Results for the first 50 cases served as baseline data. For the second 50 cases, confidence in rendering a diagnosis in the telepathology mode was essentially identical to that of making a diagnosis in the LM viewing mode. Viewing times in the telepathology mode also improved with more experience using the telepathology system. These results support the concept that an off-site pathologist using dynamic-robotic telepathology can substitute for an on-site pathologist as a service provider.

Diagnostic accuracy of an international static-imaging telepathology consultation service

Static-image and dynamic- (real-time) image telepathology are competing technologies. Although some studies suggest that the diagnostic accuracy of the dynamic-image telepathology approaches the accuracy of light microscopy, few reports have documented the diagnostic accuracy of static-image telepathology as used in the setting of an actual surgical pathology consultation practice. We report the results of an analysis of 171 telepathology consultation cases submitted to the Arizona-International Telemedicine Network (AITN). Digital images were submitted by pathologists from six participating institutions in Arizona, Mexico, and China. Telepathologists could render a telepathology diagnosis (TP) or defer rendering a diagnosis to obtain additional video images, glass slides for detailed analysis, or to obtain tissue blocks for special studies such as immunohistochemistry. The telepathologists rendered diagnoses for 144 cases and deferred 27 cases. Two pathologists retrospectively evaluated-glass slides from each case and rendered a consensus glass slide (GS) "truth" diagnosis. There was 88.2% concordance between TP and GS diagnoses (127 of 144 diagnoses). Concordance of 96.5% was achieved for clinically important diagnoses (139 of 144 diagnoses). Telepathologists deferred making a diagnosis to obtain glass slides for conventional light microscopy in 14 cases (8.1%) and for results of immunohistochemistry studies in 13 cases (7.6%). Thus, correct diagnoses were rendered by static-image telepathology in 127 of 171 cases (74.3%) at the time of telepathology diagnostic sessions. Inappropriate field selection and sampling biases of referring pathologists, as well as a tendency of static-image telepathologists to underestimate the complexity of some cases, may reduce the value of consultations based on the viewing of static images.

Performance of small diameter synthetic vascular prostheses with confluent autologous endothelial cell linings

Autologous grafts are superior to their synthetic counter-parts for grafting arteries smaller than 6-mm diameter both in terms of acute thrombogenicity and chronic intimal hyperplasia. Endothelial cell (EC) coating of the blood contacting surface may reduce thrombogenicity of synthetic small diameter vascular prostheses. In this study, the survival of EC monolayers on synthetic 4-mm diameter arterial prostheses over short-term implantations (< or = 6 weeks) was examined. Graft types examined were expanded polytetra-fluoroethylene (ePTFE) and microporous polyurethane (PU). Lumenal coverage with ECs was achieved by culturing ovine ECs on prostheses treated by either physical adsorption or covalent binding of ovine fibronectin (Fn). An ovine carotid interposition model was used to examine the performance of EC coated ePTFE and microporous PU over implantation periods of 1, 3, and 6 weeks. Outcomes assessed at the end of each experiment were graft patency, area covered by ECs, and thrombus free surface area (TFSA). Fn concentration, cell density at the time of coating and prostacyclin production in vitro were similar for both graft types. Occlusion occurred more frequently in unseeded grafts compared with EC coated grafts over 3 and 6 week implantation periods; however, the difference was not significant (p = 0.099). In prostheses precoated with ECs, approximately 40-60% of the surface area remained covered with endothelial-like cells following the first postoperative week. Recovery of EC layers occurred rapidly thereafter with 80-90% coverage at 3 weeks. TFSA remained low in comparison to EC cover in these prostheses until between 3 and 6 weeks postoperatively, suggesting a lag phase in recovery of EC function of seeded cells. In contrast, EC cover of unseeded prostheses only achieved 10-30% at 3 weeks, primarily by pannus EC ingrowth from the adjacent artery. TFSA of unseeded grafts increased in direct proportion to EC cover over time suggesting that there was no lag phase in function of these ingrowing cells.

In vivo patency of endothelial cell-lined expanded polytetrafluoroethylene prostheses in an ovine model

The performance of small-diameter vascular prostheses may be improved by implantation of grafts lined with endothelial cells. Expanded polytetrafluoroethylene (ePTFE) prostheses (4 mm x 40 mm) were coated with fibronectin (20 micrograms/ml), seeded with endothelial cells, and cultured for 48 h to produce a confluent, autologous endothelial cell lining. They were implanted as carotid interposition grafts in sheep. Seeded ePTFE grafts were compared with nonseeded ePTFE grafts and autologous carotid artery grafts. No anticoagulant or antiplatelet therapy was administered, making this a stringent test model for the thromboresistance of a small-diameter prosthesis. After 13 weeks the patencies of seeded, nonseeded, and autologous artery grafts were 16% (1/6), 0% (0/6), and 100% (6/6), respectively. The one seeded graft that was patent was fully lined with endothelial cells and showed no stenosis. The remaining five seeded grafts were occluded by fibrous tissue and displayed substantial spindle cell hyperplasia. There was no apparent difference between the autologous artery grafts and normal arterial tissue, and the anastomoses showed no stenosis. The ovine model provides a conservative test of prosthesis survival and may be useful for study of graft failure.

Autopsy findings in cardiac transplant patients. A 10-year experience

Findings from 44 autopsy examinations of cardiac transplant patients during a 10-year period were reviewed. The autopsy rate was 85%. One half of the autopsy patients underwent original transplantation for ischemic heart disease and 34% for cardiomyopathy. Survival after transplantation ranged from 0 (intraoperative) to 91 months. Rejection (including hyperacute rejection) was responsible for 41% of deaths, followed by infection (25%), and intraoperative deaths at first transplantation (9%). Most of the remaining complications were related to surgery or artificial heart support, accelerated allograft atherosclerosis, and lymphoma. Infections were not only responsible for a substantial percentage of deaths but were also a co-morbid finding in a number of patients who died primarily of other causes. Pulmonary infections represented the most common anatomic site. Twenty-five percent of the autopsy patients had gastrointestinal and/or pancreatic abnormalities, principally mucosal inflammation, erosions or hemorrhage, and pancreatitis. Review of premortem rejection history indicated that 64% of patients who died of or with rejection at autopsy had had an episode of rejection 3 weeks after transplantation and/or at least one episode of severe rejection.

Comparison of catheter ablation using radiofrequency versus direct current energy: biophysical, electrophysiologic and pathologic observations

The effects of catheter ablation with radiofrequency versus direct current energy were compared in 18 dogs assigned to two groups (of 9 dogs each). Each dog underwent a single ablation at two sites in the left ventricle at energy levels of 100, 200 or 300 J delivered in unipolar configuration to six dogs each. A transient decrease in left ventricular systolic pressure (from 121.3 +/- 24.5 to 94.2 +/- 18.7 mm Hg, p less than 0.01) and wall motion abnormality were noted in dogs with direct current shock. The left ventricular ejection fraction decreased (from 50 +/- 2% to 34 +/- 3%, p less than 0.001) shortly after direct current ablation but improved 4 weeks later to 43 +/- 3%. There were no significant changes in left ventricular pressure, wall motion or ejection fraction in dogs in the radiofrequency ablation group. Sustained ventricular tachycardia (greater than or equal to 30 s) was seen immediately after direct current shock in all dogs, and one dog died of intractable ventricular fibrillation. A 24-h ambulatory electrocardiographic (ECG) monitor obtained immediately after the procedure showed multiple runs of ventricular tachycardia in all dogs exposed to direct current ablation but in only three dogs that underwent radiofrequency ablation. No differences were found in peak creatine kinase, complete blood count with smear and B-beta 15-42 fibrinopeptide levels. Pathologically, direct current-induced lesions were larger (mean length x width x depth 10.9 x 7.5 x 5.2 vs. 4.8 x 4.6 x 4.3 mm) and were poorly circumscribed with inhomogeneous margins of necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute aortic occlusion presenting with lower limb paralysis

In a two year period eight patients have presented with acute aortic occlusion and a poor outcome in seven. Initial failure to diagnose aortic occlusion, with a mean delay from presentation to diagnosis of 24 hours, was mainly responsible. All patients had varying degrees of paralysis on presentation which misled clinicians although other findings of acute ischaemia (pain, absent pulses, colour change and anaesthesia) were always present. Two patients were initially referred to a neurologist, another to a neurosurgeon, and the fourth to an orthopaedic surgeon. Even after diagnosis had been established, the need for urgent revascularization was not always recognized, the mean time from diagnosis to revascularization being 13 hours. Unnecessary aortography contributed to this delay in four patients. In two patients operative treatment was not undertaken while six were treated operatively by: aortic bifurcation graft (3), aortic thromboendarterectomy and femoropopliteal bypass (1), open aortic embolectomy (1) and bilateral femoral embolectomy (1). The causes of aortic occlusion were thrombosis of an atherosclerotic aorta (5), thrombosis of an aneurysm (2) and embolism (1). In the latter patient, the heparin induced thrombocytopenia syndrome (HITS) was primarily responsible. The outcomes in the eight patients were death (5), paraplegia (1), amputation (1), and uncomplicated recovery (1). The single patient who made an uncomplicated recovery had the shortest delay from presentation to revascularization of only 2 1/4 hours. Acute aortic occlusion rivals aortic rupture as a vascular emergency and demands immediate operative intervention.

Merkel cell carcinoma. Improved locoregional control with postoperative radiation therapy

Between April 1981 and May 1990, 11 patients with Merkel cell carcinoma were treated with radiation therapy in Tucson, Arizona. The length of follow-up time from the time of irradiation ranged from 6 to 64 months. Locoregional control was maintained in seven of eight patients treated with surgery and postoperative radiation therapy for primary or recurrent cancer. The other three patients had bulky metastatic disease at the time of referral. Palliation was achieved in all three patients with radiation therapy. Hyperthermia also appeared to be beneficial in the one patient in which it was used, and chemotherapy achieved responses in two of four patients. These results, combined with a review of the literature, suggest that the administration of radiation therapy postoperatively to both the surgical bed and the draining lymph nodes improves locoregional control and may result in long-term disease-free survival when administered after the initial surgical resection.

Thoracoabdominal aortic aneurysm reconstruction

Thoracoabdominal aortic reconstruction distal to the left subclavian artery was carried out on 19 patients between 1974 and 1990. Screening procedures to detect cardiac, respiratory or renal impairment were undertaken in all patients. Reconstruction was in the upper third of the descending aorta in 6 patients, middle third in 6 patients, and lower third in 7 patients. The Crawford inclusion technique was used in all cases. There were six deaths, four of which were from the high reconstruction group, and one each from the middle and lower group. Paraparesis occurred in 4 patients, 2 of whom survived with some impairment. Temporary renal failure was seen in 2 patients, liver failure in 2, respiratory failure in 2, sepsis in 1, myocardial infarction in 1, and severe coagulopathy in 3. The perioperative mortality rate was 32% for the group as a whole and 15% for reconstructions which started at the middle or lower thoracic level. We conclude that the mortality rate for the middle and lower reconstructions is acceptable but that alternative techniques for the high aneurysms should be sought.

Transcatheter radiofrequency ablation in the canine right atrium

The feasibility of using radiofrequency energy for potential ablation of atrial tachycardia foci was assessed by performing transcatheter ablation in the right atrium in 11 closed-chest dogs. Single-pulsed radiofrequency (750 kHz) energy was delivered to the right atrium (29-254 J) between the tip electrode of a standard 6 Fr quadripolar catheter and a chest patch electrode. There were no significant arrhythmias or complications noted. Dogs were sacrificed 0-29 days after ablation to assess acute and subacute effects of this technique. Of 47 attempted ablations, 36 well-delineated coagulative lesions were identified. The lesions had a mean dimension of 5.2 +/- 0.57 mm (+/- SE) in length, 3.9 +/- 0.27 mm in width, and 2.6 +/- 0.17 mm in depth. Transmural necrosis was noted in 6 of 36 lesions (17%) without perforation. A thin layer of mural thrombus was found in 5 of 36 lesions (14%). Thus, this technique appears to be feasible and relatively safe for right atrial ablations in a short-term follow-up period. The potential application of this method to ablate right atrial tachycardia foci needs to be further investigated.

Initial experience of intra-operative red cell salvage

The use of red cell saving machines is described in 16 cases of aortic reconstruction. There were 3 deaths in the series, all unrelated to use of the technique. Salvaged autologous blood accounted for 45% of red cell requirements. Biochemical and haematologic parameters were monitored before, during and after operation. When large volumes of blood are salvaged, the system becomes cost effective and the risks of homologous transfusion are reduced.

A diagnostic expert system for colonic lesions

The diagnostic expert system for colonic lesions (DESCL) was designed to discriminate colonic adenoma and adenocarcinoma from normal colonic tissue. Although it was originally developed for use in conjunction with a machine vision analytic system, the DESCL has evolved into a teaching tool and a model for conceptual machine learning. The expert system is table driven and consists of a shell and a knowledge base. The latter comprises a series of architectural and cytologic observations and a quantitative estimate of diagnostic importance relating these observations to diagnostic outcome. In a validation study of 100 colonic lesions, the expert system achieved a success rate of 98%. It has the flexibility to allow individual pathologists to "customize" the knowledge base to suit their diagnostic criteria.

Quantitative light and electron microscopic correlations of nuclear features in papillary thyroid and ovarian carcinomas

The light microscopic (LM) and electron microscopic (EM) features of nuclear bodies and nucleoli were quantitatively compared in ten papillary carcinomas each of thyroid (PC-Thy) and ovarian (PC-Ovar) origins, along with eight nonthyroid, nonovarian papillary neoplasms from other organs (PN-Oth). In each neoplasm, 100 randomly selected nuclei were scored for the presence of characteristic nuclear bodies; these were defined at the LM level by the presence of a central density surrounded by a clear halo, which corresponded to four distinct quantifiable images at the EM level. Means (+/- standard deviations) of the nucleolar frequency factor, the nucleolar area and the computed total nucleolar area (the product of the nuclear frequency factor and the mean nucleolar area) were assessed for the EM images. The number of nuclear bodies was 11.9 +/- 10.7 for PC-Thy, 5.2 +/- 5.3 for PC-Ovar and 5.9 +/- 7.4 for PN-Oth; the means for PC-Thy and PC-Ovar were significantly different (P less than .03), as were the means for PC-Thy and PN-Oth (P less than .04). The nucleolar frequency factor was 0.60 +/- 0.19 for PC-Thy, 1.19 +/- 0.51 for PC-Ovar and 0.99 +/- 0.22 for PN-Oth; these means were significantly different for PC-Thy versus PC-Ovar (P less than .01) and for PC-Thy versus PN-Oth (P less than .001). The mean nucleolar area was 1.19 +/- 0.45 for PC-Thy, 1.91 +/- 0.92 for PC-Ovar and 1.94 +/- 0.76 for PN-Oth; the means were significantly different for PC-Thy and PC-Ovar (P less than .05) and for PC-Thy and PN-Oth (P less than .05). The computed total nucleolar area was 0.73 +/- 0.41 for PC-Thy, 2.17 +/- 1.09 for PC-Ovar and 1.94 +/- 1.00 for PN-Oth; these means were significantly different for PC-Thy versus PC-Ovar (P less than .001) and for PC-Thy versus PN-Oth (P less than .01). A comparison of the total number of nuclear bodies, as determined by both LM and EM, indicated a significant correlation for the PC-Ovar (P less than .01) and PN-Oth (P less than .001) groups using linear regression analysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Chronic incomplete atrioventricular block induced by radiofrequency catheter ablation

To determine if catheter ablation of the atrioventricular (AV) junction with radiofrequency energy can induce chronic incomplete (first- and second-degree) AV block to avoid the need for a permanent pacemaker, 20 closed-chest dogs were studied. Group 1 (10 dogs) received radiofrequency energy (750 kHz) with a fixed power setting (5 or 10 W) while increasing the pulse duration from 10 to 50 seconds for each application. Group 2 (10 dogs) received energy with a fixed pulse duration (20 or 30 seconds) while increasing the power setting from 5 to 10 W or from 10 to 20 W during each energy delivery. Radiofrequency energy was delivered between a chest-patch electrode and the distal electrode of a regular 7F tripolar His bundle catheter. For each application, the energy delivery was interrupted when 1) the PR interval prolonged (greater than 50%) or 2) second-degree or complete AV block occurred and persisted up to 5 seconds. The ablation procedure ended when there was 1) persistent PR prolongation (greater than 50%) or persistent second-degree AV block (lasting greater than 30 minutes) after ablation, 2) occurrence of two consecutive transient (less than 1 minute) complete AV blocks after each energy delivery, or 3) complete AV block (lasting greater than 2 minutes) after ablation. Of seven dogs in group 1 and five dogs in group 2 in which incomplete AV block was achieved 1 hour after the procedure, six in group 1 and five in group 2 remained in incomplete AV block 2-3 months after ablation. One dog in group 1 progressed into complete AV block. Of the remaining three dogs in group 1 and five dogs in group 2 in which complete AV block was initially achieved 1 hour after ablation, two in group 1 and four in group 2 continued to have complete AV block, whereas one in each group had AV conduction returned to incomplete at 1-2 months of follow-up. Thus, a total of 13 dogs had chronic incomplete AV block induced by radiofrequency catheter ablation. Pathologic examination of the conduction system in two dogs with first-degree AV block, two dogs with second-degree AV block, and one dog with complete AV block showed discrete scars involving the approaches to the AV node and the AV node itself. It is concluded that, in most dogs studied, chronic incomplete AV block could be achieved by careful titration of the dosage of radiofrequency energy and by regulation of the ablation end points.

Ultrastructural morphometric analysis of papillary neoplasms: biological and diagnostic relevance

Ten papillary adenocarcinomas of thyroid origin (P-Thy), ten papillary adenocarcinomas of ovarian origin (P-Ov), and eight papillary neoplasms of non-thyroid/non-ovarian origin (P-Other) were morphometrically compared using 19 distinct quantitative nuclear and nucleolar parameters as a database for diagnosis. The selected cases consisted of 16 primary and 12 metastatic neoplasms. It was determined that the P-Thy group had a significantly smaller nucleolar area (NuA) and nucleolar perimeter (NuP), and smaller SDs of nuclear area (NA), NuA, and NuP compared with the P-Ov and P-Other groups (P less than .05). The P-Ov group had a significantly smaller SD of NA compared with the P-Other group (P less than .05). The P-Ov group exhibited the greatest variability among the papillary neoplasms. Linear regression analysis indicated that in the P-Thy group alone there was a significant correlation between mean nuclear form factor (4 pi A/P2) and mean NuA (r = -.82; P less than .01), and mean NP and mean NuA (r = +.77; P less than .01). Linear regression analysis also indicated that in the P-Ov group alone, there was a significant correlation between mean NA and mean NuA (r = +.75; P less than .02). Morphometric domains were established using statistically significant sets of variables that distinguished between the groups. The application of three-dimensional computerized cluster analysis techniques indicated that the P-Thy group consistently had the smallest morphometric domains. It was concluded that ultrastructural morphometric analysis of papillary neoplasms has diagnostic potential and reveals interesting biological relationships among distinct nuclear features in the different groups of neoplasms.

Determinants of impedance rise during catheter ablation of bovine myocardium with radiofrequency energy

Recently, radiofrequency (RF) energy has been used as an alternative energy source to direct-current (DC) electricity for catheter ablation of recurrent tachyarrhythmias. Since delivered energy is inversely related to impedance, factors that cause impedance rise during catheter ablation impede the ability to ablate tissue. To elucidate some of the factors responsible for impedance rise during RF (750 kHz) catheter ablation using a constant voltage RF generator, the effects of the following variables on impedance were studied in an in vitro bovine heart model: power setting (10-70 W), pulse duration (10-60 sec), catheter contact pressure (5-120 gm), repeated applications (2-4), and immersion media (saline vs citrated blood). Baseline impedance in blood was twice that of saline (190 vs 80 ohm) and rises in impedances occurred more rapidly in blood for the same energy settings. Increased power settings (greater than or equal to 30 W) and pulse duration (greater than or equal to 30 sec at 20 W) were associated with impedance rises in blood medium. Typically, impedance rises in blood were associated with blood coagulum on the catheter electrodes. Impedance rises in both saline and blood media were also associated with tissue charring and endocardial surface disruption. Once a rise in impedance occurred at the ablation site, repeated applications to the same site resulted in a more rapid rise in impedance. Catheter contact pressure of 80 gm or more also resulted in rapid impedance rise. These data suggest that factors other than set power and duration may also contribute to impedance rises during RF ablation. These findings may have important clinical implications in performing catheter ablation with RF energy.

Catheter ablation of the ventricular septum with radiofrequency energy

The safety and feasibility of performing catheter ablation of the ventricular septum with radiofrequency energy was assessed in a closed-chest canine model. Radiofrequency energy (750 kHz) was delivered in a bipolar manner via the distal electrodes of two quadripolar catheters positioned across the ventricular septum in 10 dogs at two sites. Each site received from 159 to 823 joules of delivered energy over one to three applications. Four additional dogs underwent unipolar radiofrequency ablation with 331 to 767 joules of delivered energy to each septal site. No significant acute or latent arrhythmias were noted. Dogs were killed at 1 day, and at 1, 2, and 4 weeks after the procedure. Out of a possible 40 potential ablation sites on each side of the septum after bipolar ablation, 21 (53%) discrete endocardial lesions were identified, ranging in size from 4 x 3 x 1.5 to 10 x 8 x 4 mm. When 352 joules or more delivered energy was applied per site, lesions were located at 18 of 28 (64%) possible sites. After unipolar radiofrequency ablation, similarly sized lesions were identified at 15 of 16 (94%) ablation sites. Histologic examination demonstrated well-delineated round or ovoid-shaped lesions with microscopic thrombi overlying two lesions. In conclusion, catheter ablation of the ventricular septum with radiofrequency energy appears capable of safely producing discrete areas of necrosis and may provide an alternative to direct current (DC) energy for catheter ablation of ventricular tachycardia originating from the septum.

Comparison of saphenous vein patch, polytetrafluoroethylene patch, and direct arteriotomy closure after carotid endarterectomy. Part I. Perioperative results

To evaluate the perioperative outcomes and the immediate increases in size after patch closure, 140 carotid endarterectomies were randomized into one of three groups: direct no-patch closure, saphenous vein patch closure, and polytetrafluoroethylene patch closure. Seven patients (4.4%) experienced signs of cerebral ischemia in the immediate postoperative period. In three cases this was transient and reversible. In the other four reexploration was undertaken and carotid thrombosis was corrected by thrombectomy. The condition of one of these patients deteriorated to a permanent stroke, whereas the other patients made a complete recovery. Neurologic complications were more frequent in the no-patch group, but the differences between the groups were not significant. The incidence of perioperative internal carotid stenosis, aneurysmal dilatation, and other morphologic abnormalities was assessed in 131 intravenous digital subtraction angiograms taken before the patient was discharged from the hospital. Eight (17.0%) of the endarterectomies in the no-patch group were narrowed by 30% to 50% diameter stenosis, whereas none of the patched arteries had more than 30% stenosis. In contrast, dilatation of the common or internal carotid artery to more than twice the measured diameter was absent in non-patched arteries but was present in seven (17.0%) saphenous patch closures and four (9.23%) polytetrafluoroethylene patch closures. We conclude that patch closure after carotid endarterectomy is less likely to cause stenosis in the perioperative period. Poly-tetrafluoroethylene patches resist dilatation better than do saphenous vein patches and are less likely to become aneurysmal.

Gastrointestinal complications after human transplantation and mechanical heart replacement

One hundred fifty-three patients underwent 159 heart transplants; 7 of these patients received 8 artificial hearts used as a bridge before implantation. The 1-year survival rate was 81 percent. One hundred forty gastrointestinal complications developed in 70 patients. Thirty-eight operations were required. Twenty-nine were intraabdominal operations. Of these, 22 were elective and 7 were emergency procedures. Five of the seven patients who underwent emergency procedures died, for an overall total mortality rate of 17 percent for major intraabdominal interventions. There were no complications or deaths in patients who underwent elective procedures. Major elective intraabdominal surgical interventions can be safely carried out in heart transplant patients. Repeated physical examination, aggressive use of endoscopy and imaging techniques, sound surgical judgement and a mutual relationship of trust and respect between cardiac and general surgeons are keys to a successful outcome.

Symptomatic carotid restenosis

Between May, 1969, and December, 1985, 680 carotid endarterectomies were carried out in the Surgical Professorial Unit in St. Vincent's Hospital, Sydney. Recurrence requiring re-operation was detected in nine arteries in seven patients. Continued smoking after the initial operation may have contributed to the restenoses. The origin of the internal carotid artery was the most common site of recurrence, irrespective of whether restenosis was caused by myointimal fibroplasia or recurrent atheroma.

Combined gastrointestinal and abdominal aortic aneurysm operations

Experience with gastrointestinal surgical conditions in 154 consecutive aneurysm operations at St Vincent's Hospital, Sydney, over 5 years (1982-86) is reported. Seventeen patients (11%) had coincidental gallstones, and six patients had other gastrointestinal conditions. Postoperative gastrointestinal complications occurred in eight patients. The overall in-hospital mortality rate was 7.8%. Four of the 12 deaths were associated with gastrointestinal problems, but these complications first developed after aneurysm surgery in three patients and could not have been avoided by a concurrent operation. The management of gastrointestinal pathology in association with the treatment of abdominal aneurysm is reviewed. The coincidence of these disorders is not sufficiently frequent to allow valid comment on the probability of successful outcomes, but the risks posed by surgically untreated gastrointestinal conditions are low, so that secondary gastrointestinal procedures should be avoided in most aneurysm operations.

Micromorphometry of colonic lesions

In the formulation of a quantitative component for the knowledge base of a diagnostic expert system, we developed a mathematical model to describe nuclear placement patterns in colon. Glands from normal colon, tubular adenomas, and adenocarcinomas were studied, and a ratio developed of percentage internally displaced nuclei to percentage displacement area. This displacement area represented an inner epithelial zone bounded centrally by the lumen and peripherally by the apical limit of basal nuclei. The mean percentage internally displaced nuclei to percentage displacement area ratio was 0.15 +/- 0.13 for normal glands, 0.75 +/- 0.09 for adenomas, and 1.04 +/- 0.13 for carcinomas. When the percentage internally displaced nuclei to percentage displacement area ratio was plotted against total number of nuclei, there was statistically significant separation of the diagnostic categories at alpha less than or equal to 0.05. Relative nuclear area and its variance were also studied for normal colonic glands, adenomas, and adenocarcinomas. Mean relative nuclear area for cells from normal glands was 284.2, from adenomas 342.4, and from adenocarcinomas 416.4, these being statistically significantly different at alpha less than or equal to 0.05. Variance of relative nuclear area, compared for the three diagnostic categories, was statistically significantly increased only in adenocarcinoma. Quantitation of nuclear placement patterns appears to provide a useful diagnostic clue for the knowledge base of a diagnostic expert system in the discrimination among normal colonic glands, adenomas, and adenocarcinomas.

Short- and long-term effects of transcatheter ablation of the coronary sinus by radiofrequency energy

Catheter ablation of left-sided atrioventricular accessory pathways through the coronary sinus by direct-current shock may be complicated by rupture and thrombosis of the coronary sinus and injury to the coronary arteries. This study examined short and long-term effects of radiofrequency catheter ablation of the coronary sinus in 20 closed-chest dogs to determine whether this technique is feasible for potential interruption of left-sided accessory pathways. Single-pulsed radiofrequency energy (750 kHz, 85-293 J) was delivered to three sites in the distal and middle coronary sinus between the distal (1) or the proximal electrodes (2 or 3) of a standard 6 French quadripolar catheter and a chest-wall patch electrode. Single-pulsed radiofrequency energy (78-293 J) was also applied to two sites near the ostium of the coronary sinus with the proximal (4) or the distal (1) electrode of the same catheter. Coronary artery and levophase coronary sinus angiograms obtained before and immediately after ablation, as well as before killing, showed intact vascular structures in all dogs. Right atrial, pulmonary arterial, and aortic pressures measured in three dogs did not change significantly at the time of energy delivery. No significant changes were found in atrioventricular nodal refractoriness and conduction. None of the dogs had significant rhythm disturbances during and after ablation as evaluated by ambulatory electrocardiographic monitoring and periodic rhythm strips at follow-up. Ten dogs were killed 1-7 days after ablation, three dogs were killed at 4 weeks, three dogs at 6 weeks, two dogs at 8 weeks, and two dogs at 12 weeks. Discrete lesions ranging in size from 3 x 3 to 8 x 10 mm2 in surface area and 0.5-4.5 mm in depth were found in the coronary sinus with most of the lesions extending to the left atrial and left ventricular myocardium. There was neither rupture of the coronary sinus nor occlusion of the coronary arteries. Mural thrombus was found in the coronary sinus on five acute lesions in two dogs, but none was noted on the chronic lesions, which was characterized by chronic granulation tissue and fibrosis. Two dogs in the study during chronic conditions had damage to branches of the underlying coronary artery that showed necrotizing arteritis and arterial sclerosis. Conduction system studies in four dogs showed some chronic inflammatory and fibrotic changes. Similar discrete lesions were found in situ in the coronary sinus of four postmortem human hearts with radiofrequency catheter ablation.(ABSTRACT TRUNCATED AT 400 WORDS)

Quantitative pathology of coccidioidomycosis in acquired immunodeficiency syndrome

This study examines the laboratory aspects of diagnosis of coccidioidomycosis in 11 patients with acquired immunodeficiency syndrome (AIDS) and the qualitative and quantitative differences between host responses of AIDS and non-AIDS patients who died with disseminated coccidioidomycosis. Material obtained at bronchoscopy confirmed the diagnosis of pulmonary coccidioidomycosis in 67% (6/9) of the patients. Patients with AIDS had a generally poor granulomatous response and statistically significantly increased numbers of spherules in lung tissue compared with non-AIDS patients. Neither antifungal therapy nor duration of clinical disease influenced the number of organisms present. The findings suggest a parallel between AIDS-associated coccidioidomycosis and other granulomatous diseases such as leprosy and schistosomiasis, in which the type of granuloma formation and organism numbers are influenced by the T-lymphocyte milieu.

Prospective randomized trial of polytetrafluoroethylene and Dacron aortic prosthesis. I. Perioperative results

Over a two year period 80 patients were entered into a prospective randomized trial comparing polytetrafluoroethylene (PTFE) and Dacron infrarenal aortic reconstructions. Fifty-four patients were treated for aneurysm (30 single tubed grafts; 24 bifurcation grafts), and 26 patients were treated for occlusive disease (26 bifurcation grafts). The groups were matched for age, sex and preoperative risk factors. Five patients died after operation (6.3%) including two from hemorrhage, but there were no significant differences in mortality and morbidity between the PTFE and Dacron groups. The volume of blood lost at operation (1930 +/- 1340 ml, all patients); the volume of blood transfused (2.98 +/- 2.43 units); the volume of crystalloids infused (3050 +/- 1390 ml); the intraoperative heparin dosage (67.9 +/- 20.5 mg); the clamp time (71.6 +/- 34.5 min); and the total operating time (228.1 +/- 78.3 min) also showed no significant differences between PTFE and Dacron. The ankle systolic pressure index rose more for PTFE (0.96 +/- 0.24) than for Dacron (0.82 +/- 0.20; P less than 0.002) at the time of discharge. This partially reflects a difference in the index between the groups before operation (PTFE 0.79 +/- 0.30; Dacron 0.72 +/- 0.32), but it may also indicate that PTFE is less thrombogenic than Dacron.

Radiofrequency catheter ablation of the left and right ventricles: anatomic and electrophysiologic observations

Certain untoward effects associated with the use of direct-current electrical catheter ablation of the ventricular endomyocardium have been noted. We assessed the efficacy and safety of closed-chest catheter ablation of the left and right ventricles using radiofrequency (RF) energy (750 kHz) in six dogs. Mean RF energies between 93 and 123 joules (J) were randomly delivered to three left ventricular (LV) sites via two distal adjacent electrodes (bipolar configuration) using 6-7F USCI tripolar or quadripolar catheters with an interelectrode distance of 5-10 mm. Another 90-143 J were given to two right ventricular (RV) sites in single or multiple divided applications between a distal electrode and an external patch electrode (unipolar configuration). Ventricular arrhythmias were not observed during application of RF energy. Programmed ventricular stimulation before and after the procedure did not induce ventricular tachycardia (VT) or fibrillation except in one dog who had inducible VT prior to ablation. There were no significant changes in LV and RV effective refractory periods after the procedures. Occasional premature ventricular beats and rare episodes of non-sustained VT (3-12 beats) were observed in ambulatory electrocardiographic recordings (13-24 hrs) done immediately after ablation. Dogs were sacrificed after 4-5 days. Pathology showed well-demarcated round or ovoid lesions of varying sizes. Mural thrombus was found in one dog. Microscopic findings consisted of circumscribed areas of coagulation necrosis with a peripheral zone of cellular infiltration. Transmural necrosis without perforation was occasionally seen in the thin RV wall when higher energies were delivered. In conclusion, discrete areas of desiccation injury in the ventricles can be achieved by transcatheter bipolar or unipolar ablation using RF energy. The complications associated with this method appear to be minimal. Further experiments are needed to evaluate its potential for catheter ablation of ventricular tachycardia.

Colonic lesion expert system. Performance evaluation

A computer-based expert system for diagnosing colonic sections as normal, adenoma or adenocarcinoma is described, along with an evaluation of its performance. On the basis of its knowledge base, consisting of the values of diagnostic clues and their associated certainty factors for the possible diagnoses, the system will suggest the diagnosis for new cases presented to it. Using the data provided for 16 diagnostic clues, the system arrived at correct diagnoses for all cases of normal colon, for 49 of 50 cases of adenoma and for 48 of 49 cases of adenocarcinoma. Sample outputs from the expert system are presented and discussed, and the effects of possible alterations in the data base are considered.

Duodenal obstruction following abdominal aortic reconstruction

Four patients developed duodenal obstruction after 161 abdominal aortic reconstructions, an incidence (2.5%) rivaling that of graft infection and arterioenteric fistula. The diagnosis is easily confirmed by gastrointestinal contrast studies. Duodenal obstruction is usually caused by perigraft collagenous adhesions and is probably less likely to occur if the mobilized duodenum is not replaced directly over the aorta during resuture of the retroperitoneum. Undetected duodenal obstruction leads to rapid dehydration and electrolyte and caloric depletion.

5-year experience with intravesical therapy of carcinoma in situ: an inquiry into the risks of "conservative" management

Recent reports of disease progression in patients being treated with intravesical agents for carcinoma in situ of the bladder led us to examine our 5-year experience with 26 consecutive patients with carcinoma in situ treated with intravesical therapy for this lesion. Nine patients with isolated carcinoma in situ and 17 with carcinoma in situ associated with papillary lesions were treated intravesically with a variety of agents in a closely monitored program for a mean of 22 months. All patients wished to exhaust conservative options before accepting cystectomy. Of 26 patients treated 9 (35 per cent) have no evidence of disease with a functional bladder after 27 months, 13 (50 per cent) are treatment failures and 4 (15 per cent) maintain an equivocal status to date. Successful treatment results with each drug were 6 of 24 thiotepa, 0 of 7 mitomycin, 0 of 6 doxorubicin and 3 of 8 bacillus Calmette-Guerin. Treatment failure was associated with disease progression to muscle invasion, adjacent organ invasion or metastases in 7 patients (27 per cent). Significant reduction in bladder capacity after prolonged therapy occurred in 3 patients. Our results suggest that persistent, intensive, "conservative" intravesical therapy in the face of recurrent or persistent disease is associated with substantial patient risk.

Morphometry in surgical pathology

The potential role of morphometry in surgical pathology is discussed. Specific areas in which morphometry could be helpful are in (1) identifying malignant cells in lesions that are largely composed of benign-appearing cells (e.g., follicular thyroid neoplasms), (2) defining reference points in apparent continua (e.g., in the progression from normal colon to adenoma to adenocarcinoma), (3) distinguishing between benign and malignant lesions with similar appearances (e.g., fibromatosis and fibrosarcoma of the soft tissue) and (4) distinguishing between similar-appearing types of malignant neoplasms (e.g., between small-cell carcinoma of the lung and small-cell lymphoma). Morphometric techniques are already being used in DNA ploidy determinations, which frequently bear prognostic information. The measurement of other nuclear and cellular parameters has been used for both diagnostic and prognostic ends; one example is the relation of nuclear roundness to metastatic potential in prostatic carcinomas. Morphometry is now being increasingly applied to histologic sections, as in the prognostic study of lesion thickness in malignant melanoma and the diagnostic study of glandular architecture in colonic adenoma. The use of morphometry can enhance the observation and interpretation of morphologic features, which, combined with the clinical data and the experience of the pathologist, can lead to greater accuracy and precision in surgical pathology diagnoses.

Carotid endarterectomy, siphon stenosis, collateral hemispheric pressure, and perioperative cerebral infarction

To determine whether moderate stenosis (50% to 80%) of the intracranial segment of the internal carotid artery increases the risk of cerebral infarction after carotid endarterectomy, the arteriograms, ocular pneumoplethysmograms, internal carotid back pressure, and clinical outcome after 169 operations were reviewed. Siphon stenoses less than 50% were not included because of their doubtful anatomic and hemodynamic significance. No patients with stenosis greater than 80% underwent operation. Moderate siphon stenosis affected 37 vessels, 24 (14.2%) ipsilateral and 13 (7.6%) contralateral to the side of operation. Eight patients had bilateral siphon stenosis. Three patients had stroke after operation; none of these cases had siphon stenosis. Moderate siphon stenosis did not increase the risk of perioperative cerebral infarction. Stroke only occurred in those patients in whom there was arteriographic or functional evidence that the affected hemisphere was isolated from effective collateral vessels.

Detection of diagnostic clues in statistical histometry

Examples are given of the detection of diagnostic clues in quantitative cytology and histopathology by statistical testing, such as may be applied in image analytical procedures. Schematic and other examples are presented of the visual images analyzed by each procedure, whose limits are also discussed. The situations analyzed include increased cellularity, differences in nuclear placement patterns, uniformity of displacement, variance in nuclear diameters and chaincode variance of nuclear placement. A specific model is presented for describing or generating a series of dependent observations representing nuclear placement, based on the Box-Jenkins (ARIMA) models for decomposing a spatial or temporal series into several components. This model describes the statistical observations that are random samples from the series. Finally, one graphic example is given in which visual inspection more readily ascertains an alteration than does statistical analysis of a modest-sized sample.

Congenital heart block and cardiac anomalies in the absence of maternal connective tissue disease

The association of congenital heart block with maternal connective tissue disease and autoimmunity has been recently reported. Two cases of heart block were diagnosed in utero at 23 and 24 weeks' gestation. Both mothers had extensive workups for connective tissue disease that were negative. Two-dimensional and Doppler echocardiography were performed in utero and both infants had left atrial isomerism, atrioventricular canal defects, and severe hydrops in addition to heart block. Review of the recent literature identifies a subset of congenital heart block in which the mothers have no evidence for connective tissue disease, and the fetus or neonate has complex cardiac malformations and hydrops. The common features in these babies are atrioventricular canal defects and isomerism. No reports of congenital heart disease among the children of mothers with connective tissue disease fit this description. Our recent experience and literature review emphasize the previously known association between congenital heart block and congenital heart disease. This association is especially important in light of the poor prognosis for this group of fetuses and neonates.

Antinuclear antibodies and survival in cardiac transplant patients

Serum from 48 patients with cardiac transplants was tested for the presence of antinuclear antibodies (ANA). Thirty-two of the sera were negative for ANA (ANA-), and 16 were positive for ANA (ANA+). Six of the ANA+ sera had a diffuse pattern, six had a peripheral pattern, three had a combined diffuse and rim pattern, and one had a diffuse and nucleolar pattern. Seven of the ANA+ sera were positive at a 1:40 titer, one at a 1:80 titer, four at a 1:160 titer, two at a 1:320 titer, and two at a 1:640 titer. Thirteen of the 32 ANA- patients have died, at intervals of one month to four years after transplantation. Fourteen of the 16 ANA+ patients have died, at intervals ranging from less than one day to four years after transplantation. The mean time period from transplantation to death was 13 +/- 15 months for the ANA+ patients: these were not statistically significantly different. However, the mean interval from transplantation to death of the ANA+ patients with an ANA titer greater than 1:40 was 0.8 +/- 0.8 months, which was significantly different from the mean survival period of the ANA+ group as a whole (P less than or equal to 0.05) and the mean survival of the ANA- group (P less than or equal to 0.005). Although the mechanism is not clear, there appears to be an association between higher titer serum ANA positivity and increased mortality in patients with cardiac transplants with significantly decreased duration of survival after transplantation.

Histopathology of acute myocardial necrosis: effects of immunosuppression therapy

Endomyocardial biopsy is currently the best method to monitor cardiac allograft rejection. The histologic criteria of infiltration by mononuclear cells with pyroninophilic cytoplasm and acute myocyte necrosis indicate immunologic activation and require an increase of immunosuppressive therapy. Of particular concern is the persistence of necrotic fibers on biopsies for some time after ischemic episodes associated with the transplant procedure and after acute rejection episodes. Because the presence of acute myocyte necrosis plays a key role in the clinical decision on immunotherapy, we evaluated the resolution pattern of acute necrotic fibers under standard immunosuppression treatment. Myocardial infarction of the posterior papillary muscle was surgically induced in two groups of dogs that were killed (three from each group) at 4, 7, 14, and 21 days after surgery. The first group consisted of 12 control animals, and the second group was composed of 12 dogs, immunosuppressed with cyclosporine, methylprednisolone, and prednisone. The histologic sections demonstrated a persistence of myocyte necrosis for 14 days after infarction in the treated group but for only 7 days in the untreated control group. This slow resolution pattern needs more emphasis in clinical practice. Criteria other than myocyte necrosis should be used to differentiate ongoing from resolving rejection after the first rejection episode. Preservation injury may persist for 2 weeks after transplantation and be misinterpreted as acute rejection.