mTOR-dependent loss of PON1 secretion and antiphospholipid autoantibody production underlie autoimmunity-mediated cirrhosis in transaldolase deficiency.

Transaldolase deficiency predisposes to chronic liver disease progressing from cirrhosis to hepatocellular carcinoma (HCC). Transition from cirrhosis to hepatocarcinogenesis depends on mitochondrial oxidative stress, as controlled by cytosolic aldose metabolism through the pentose phosphate pathway (PPP). Progression to HCC is critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Although AR inactivation blocked susceptibility to hepatocarcinogenesis, it enhanced growth restriction, carbon trapping in the non-oxidative branch of the PPP and failed to reverse the depletion of glucose 6-phosphate (G6P) and liver cirrhosis. Here, we show that inactivation of the TAL-AR axis results in metabolic stress characterized by reduced mitophagy, enhanced overall autophagy, activation of the mechanistic target of rapamycin (mTOR), diminished glycosylation and secretion of paraoxonase 1 (PON1), production of antiphospholipid autoantibodies (aPL), loss of CD161+ NK cells, and expansion of CD38+ Ito cells, which are responsive to treatment with rapamycin in vivo. The present study thus identifies glycosylation and secretion of PON1 and aPL production as mTOR-dependent regulatory checkpoints of autoimmunity underlying liver cirrhosis in TAL deficiency.

Cytosolic aldose metabolism contributes to progression from cirrhosis to hepatocarcinogenesis.

Oxidative stress modulates carcinogenesis in the liver; however, direct evidence for metabolic control of oxidative stress during pathogenesis, particularly, of progression from cirrhosis to hepatocellular carcinoma (HCC), has been lacking. Deficiency of transaldolase (TAL), a rate-limiting enzyme of the non-oxidative branch of the pentose phosphate pathway (PPP), restricts growth and predisposes to cirrhosis and HCC in mice and humans. Here, we show that mitochondrial oxidative stress and progression from cirrhosis to HCC and acetaminophen-induced liver necrosis are critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Both TAL and AR are confined to the cytosol; however, their inactivation distorts mitochondrial redox homeostasis in opposite directions. The results suggest that AR acts as a rheostat of carbon recycling and NADPH output of the PPP with broad implications for disease progression from cirrhosis to HCC.

Inheritance of osteosarcoma and Paget's disease of bone: a familial loss of heterozygosity study.

Pagetoid osteosarcoma is a complication of Paget's disease of bone. Sarcomatous transformation is most often seen in severe, long-standing Paget's disease. Familial clustering of Paget's disease has been described with apparent autosomal dominant inheritance with high penetrance by the sixth decade. Although definitive proof of the specific gene involved remains elusive, some researchers have shown loss of heterozygosity in a region of chromosome 18q in a relatively high percentage of studied patients affected with either Paget's disease alone, in Pagetoid osteosarcoma, and in uncomplicated osteosarcoma. Our patient was diagnosed with Pagetoid osteosarcoma and had a first-degree relative with history of the same. We hypothesized that our patient's tumor samples might contain a similar genetic abnormality. Our analysis of several polymorphic markers from the chromosome 18q21-22 region showed loss of maternally inherited alleles throughout the region. This finding is similar to those described previously and provides further evidence of a susceptibility region relating to this disease. This report describes a father and son, their young ages at diagnosis of Pagetoid sarcoma, the identical sites of disease involvement, and a loss of heterozygosity study illustrating the inheritance of the presumed defective gene.

Benign tumefactive soft tissue extension from Paget's disease of bone simulating malignancy.

Osteosarcoma is a frequently fatal complication of Paget's disease of bone typically manifesting radiographically as a lytic lesion with soft tissue extension. A clinically worrisome, but benign manifestation of Paget's disease simulating malignancy because of an extraosseous mass is reported.

Suprasellar monomorphous pilomyxoid neoplasm: an ultastructural analysis.

The authors report 3 patients, 2 children and 1 adult, each of whom presented with an unusual myxoid lesion reminiscent of pilocytic astrocytoma but with other features of myxopapillary ependymoma. The magnetic resonance imaging findings in all cases showed a diffusely contrast-enhancing suprasellar mass focally extending into the third ventricle. Involvement of adjacent structures was more extensive in both infants. By light microscopy, all were composed of a monotonous population of cells with delicate piloid-like processes, loosely arranged within a prominent myxoid background. Focally, the neoplastic cells converged upon small blood vessels in pseudorosette-like formations. These histomorphologic features are identical to those of the recently described astrocytoma with monomorphous pilomyxoid features. In addition, the individual tumor cells showed strong cytoplasmic immunoreactivity with antibodies to glial fibrillary acidic protein (GFAP) and vimentin, as well as nuclear and cytoplasmic staining with S-100. All stained positive for synaptophysin and negative for chromogranin. By electron microscopy, the tumor cells were bipolar with elongated processes and apical surfaces displaying microvilli, cytoplasmic blebs and rare cilia. Vesicles and coated pits were seen, as were occasional synaptoid complexes. The current study serves to expand our clincopathologic experience with this rare and enigmatic lesion, with particular attention given to the ultrastructural characteristics.

Neutrophil sequestration in the lung following acute aortic occlusion starts during ischaemia and can be attenuated by tumour necrosis factor and nitric oxide blockade.

OBJECTIVES: To investigate the role of lower extremity ischaemia in acute lung injury with special emphasis on the role of tumour necrosis factor (TNF) and nitric oxide (NO) as mediators of neutrophil (PMN) chemotaxis in the lung. DESIGN: Prospective randomised study. MATERIALS AND METHODS: Sprague-Dawley rats were randomized into four groups: group 1 (x-clmap): aorta clamped just above the bifurcation for 3 h; group 2 (AG): 50 mg/kg aminoguanidine, a specific inducible NO synthase (iNOS) inhibitor, was administered prior to aortic occlusion; group 3 (Steroids): 1 mg/kg dexamethasone was administered prior to aortic occlusion; and group 4 (TNFbp): 2 mg/kg TNFbp, a PEGylated dimeric form of the high affinity TNF receptor I (R1) was administered prior to aortic occlusion to block TNF action. Groups 2, 3 and 4 were subjected to the same ischaemia time as group 1. NO concentration in the exhaled gas (ENO) was measured in 30 min intervals. At the end of the 3 h ischaemia, one lung was excised and fixed for routine histological evaluation, and the other underwent bronchoalveolar lavage (BAL). PMN chemotaxis towards the BAL fluid was then measured using the blindwell technique. RESULTS: ENO in group 1 increased from 0.9 +/- 0.3 ppb at baseline, to 41.3 +/- 9.2 ppb at the end of ischaemia. Animals in this group exhibited significant lung inflammation. Aminoguanidine, dexamethasone and TNFbp blocked NO production (peak ENO values of 7.2 +/- 1.9, 12.6 +/- 1.3 and 8.9 +/- 1.7 ppb for groups 2, 3 and 4 respectively), decreased PMN chemotaxis and sequestration in the lung, and attenuated lung inflammation. CONCLUSIONS: Acute lung injury resulting from distal aortic occlusion starts during ischaemia. TNF and NO blockade decrease PMN chemotaxis and sequestration and attenuate the lung injury process.

Role of nitric oxide and tumor necrosis factor on lung injury caused by ischemia/reperfusion of the lower extremities.

PURPOSE: Acute aortic occlusion with subsequent ischemia/reperfusion (I/R) of the lower extremities is known to predispose to lung injury. The pathophysiologic mechanisms of this injury are not clear. In the present study, we studied the role of tumor necrosis factor (TNF) and nitric oxide (NO) in lung injury caused by lower extremity I/R. METHODS: A rat model in which the infrarenal aorta was cross-clamped for 3 hours followed by 1 hour of reperfusion was used. The rats were randomized into five groups: group 1, aorta exposed but not clamped; group 2, aorta clamped for 3 hours, followed by 1 hour of reperfusion; group 3, 1 mg/kg dexamethasone administered before the aorta was clamped; group 4, 25 mg aminoguanidine, a specific inducible NO synthase (iNOS) inhibitor, administered before the aorta was clamped; and group 5, 2 mg/kg TNFbp, a PEG-ylated dimeric form of the high-affinity p55 TNF receptor I (RI), administered before the aorta was clamped. NO concentration in the exhaled gas (ENO) was measured, as an index of NO production by the lung, in 30 minute intervals during I/R. Serial arterial blood samples for TNF assay were obtained during the course of the experiment. At the end of the experiment, the lungs were removed and histologically examined for evidence of injury. RESULTS: ENO in group 2 increased from 0.7 +/- 0.3 ppb at baseline to 54.3 +/- 7.5 ppb at the end of ischemia and remained stable during reperfusion (54.6 +/- 8.5 ppb at the end of reperfusion). ENO production was blocked by aminoguanidine, by dexamethasone, and by TNFbp given before aortic occlusion. Serum TNF in groups 2, 3 and 4 increased rapidly during early ischemia, reaching its peak value 60 minutes after occlusion of the aorta, then gradually declined to baseline levels at the end of ischemia, and remained low during reperfusion. TNFbp decreased serum TNF concentration significantly when it was given before aortic occlusion. Histologic examination of the lungs at the end of the experiment revealed that aminoguanidine, dexamethasone, and TNFbp had a protective effect on the lungs. CONCLUSIONS: Serum TNF increases rapidly during lower extremity ischemia and causes increased production of NO from the lung by upregulating iNOS. Increased NO is associated with more severe lung injury, and iNOS blockade has beneficial effects on the lung. TNF blockade before ischemia decreases NO production by the lung and attenuates lung injury. ENO can be used as an early marker of lung injury caused by lower extremity I/R.

Behavioral stress alters coronary vascular reactivity in borderline hypertensive rats.

BACKGROUND: Behavioral stress has been proposed to contribute to the occurrence of myocardial ischemia. Objective To investigate the effect of chronic exposure to behavioral stress on the function and structure of the coronary artery of borderline hypertensive rats (BHR). DESIGN: BHR were either exposed to an air-jet stress for 2 h/day for 10 days or kept in their cage for 10 days. METHODS: After 10 days, hemodynamic measurements in conscious animals were recorded, and their hearts were removed for isolation of a left ventricular coronary artery for functional studies or for fixation by retrograde perfusion for study with scanning electron microscopy. Vascular reactivity was measured in isolated coronary arteries (approximately 250 microm) maintained at an intraluminal diameter of 40 mmHg while the intraluminal diameter was recorded continuously. RESULTS: The resting mean arterial pressure and heart rate in conscious, unrestrained BHR were not altered significantly by exposure to 10 days of 2 h/day air-jet stress. Coronary artery relaxation in response to the endothelium-dependent vasodilator acetylcholine was impaired in rats exposed to the air-jet stress compared with that in controls. An attenuated response to exogenous nitric oxide in coronary arteries from stressed BHR was confirmed by the finding of a reduced sensitivity to nitroprusside, which releases nitric oxide independently from the endothelium. However, relaxation of coronary arteries in response to isoproterenol, which acts independently from nitric oxide, was not altered. Coronary artery contraction in response to endothelin-1 and phenylephrine was not altered in vessels taken from BHR exposed to behavioral stress compared with that in vessels from control rats. Scanning electron microscopy of the endothelial surface of the septal coronary artery showed no difference between vessels from control and stressed BHR. CONCLUSION: These results indicate that behavioral stress impairs endothelium-dependent and nitric oxide-mediated coronary relaxation, but does not alter alpha1-adrenoceptor or endothelin-1-mediated contraction. By impairing coronary artery vascular relaxation, chronic exposure to behavioral stress may contribute to myocardial ischemia.

Histologic characteristics of electrosurgical injuries.

STUDY OBJECTIVE: To describe the wide variation of histologic characteristics produced by electrosurgical burns. DESIGN: Retrospective analysis. SETTING: University-associated teaching hospital. SUBJECTS: Pigs and dogs. INTERVENTIONS: Various power settings were employed with both monopolar and bipolar electrodes to incur electrosurgical damage. Animals were followed for up to 96 hours after injury. MEASUREMENTS AND MAIN RESULTS: Histologic analysis yielded characteristics of electrosurgical damage including areas of complete necrosis and coagulation, perivascular changes, endothelial damage, and hyperchromic pyknotic nuclei. White cell infiltration was seen only at the margin of necrotic zones of coagulation. CONCLUSION: The wide spectrum of histology from electrosurgical burns is primarily a result of the area that is sampled. Surgeons should actively investigate any postsurgical complications involving electrosurgery to obtain a definitive cause.

Colonic tattooing with India ink: benefits, risks, and alternatives.

OBJECTIVE: To provide comprehensive information on key issues concerning colonic tattooing with India ink in reported literature. METHODS: A total of 735 citations on India ink alone were present in the English literature (1966-1995), including 16 on India ink and colonic tattooing. Nine major studies were identified and reviewed for 1) preparation before tattooing (type of ink used, sterilization process, colonic preparation, and antibiotic prophylaxis), 2) the tattooing process (technique and volume injected), 3) success in localization, and 4) complications. RESULTS: A'total of 447 cases of colonic tattooing with India ink have been reported. Major indication was preoperative marking of tumor site. Various India ink preparations were used. Ink was unsterilized in 57% (255/447), autoclaved in 42% (187/447), and gas sterilized in 1% (5/447) of cases. Colonic preparation varied similarly. Prophylactic antibiotics were used in 1% (5/447) of cases. Dilution of India ink varied from undiluted to 1:100 (with 0.9% saline). The volume injected ranged from 0.1 to 2 ml per site injected, commonly with tangential needle insertion and delivery of ink into the submucosa in the majority of the cases. Intraoperative localization was easier with multiple tattoo injections. Five reports of complications have been made. In only one instance did overt clinical complications develop. Risk of a clinical complication with colonic tattooing with India ink is 0.22%. CONCLUSION: Marked variability in technique, as well as potential for reporting bias, limit the quantitative conclusions. In general, colonic tattooing with India ink is a safe, accurate, and inexpensive method for preoperative marking and prospective study of colonic lesions.

A laparoscopic complication? A medical legal case analysis. Part I.

This article describes a case of a laparoscopic injury and the ensuing litigation. Data from the hospital report and the testimony of witnesses are presented. In the next issue of this Journal, the results of the jury finding will be presented as Part II.

An unusual case of synchronous thyroid and parathyroid adenomas.

A 52-year-old woman was evaluated for an enlarging neck mass. Fine-needle aspirate contained Hürthle cells and thyroidectomy revealed two separate thyroid morphologically similar lesions. Immunohistochemical studies confirmed diagnoses of separate Hürthle cell thyroid and oxyphil parathyroid adenomas. Diagnostic pitfalls and the role of immunohistochemistry in diagnosis are discussed.

Contrast-enhanced thin slice ultrafast computed tomography for the detection of small pulmonary emboli. Studies using autologous emboli in the pig.

RATIONALE AND OBJECTIVES: Ultrafast computed tomography (UFCT) has proven useful, but is of limited practical application in the diagnosis of central pulmonary embolism; however, its ability to detect more peripheral emboli has not been established. In this study, the use of contrast-enhanced UFCT images for the detection of autologous peripheral pulmonary emboli in the pig is evaluated. METHODS: A single autologous embolus measuring 0.7 x 1.5 cm was introduced into the superior vena cava of eight pigs. Contiguous, 3-mm axial UFCT images from the lung apex to the base were obtained before and after the introduction of the embolus. After scanning, the pigs were killed, and the thorax was removed intact and was frozen in a dry ice-alcohol mixture. Later, the thorax was sliced at 10-mm thicknesses, and the locations of the emboli were determined by a pulmonary pathologist blinded to the imaging results. Concomitantly, the locations of the emboli were determined by consensus of three chest radiologists blinded to the autopsy results. RESULTS: In 6 of 8 animals with emboli, the embolus location correlated exactly with the autopsy findings. In one, the embolus was on the same side, but 1.6 cm further distal. In the other, a marking suture was identified, but no clot was identified on the pathologic or UFCT examination. In the eight animals scanned before the introduction of the embolus, no embolus was found. Interobserver agreement was 100%. CONCLUSIONS: Ultrafast computed tomography has the potential to detect autologous emboli in second- to fourth-division pulmonary vessels. Further studies are needed to determine if in vivo emboli can be similarly visualized.

Measurement of coronary blood flow velocity in conscious rats.

This study describes a technique for the continuous recording of coronary blood flow velocity (CBV) in conscious unrestrained rats. A pulsed Doppler flow probe consisting of a 1-mm2 crystal mounted in a 4-mm suction cup was positioned over the left coronary artery of pentobarbital sodium-anesthetized rats. The probe was held in place with mild suction and sutured to the surface of the myocardium. Probes were connected to a pulsed Doppler flowmeter, which measures Doppler shift and provides an index of blood flow velocity. While rats were still anesthetized, the measurement of CBV was validated by determining that CBV peaked during diastole and increased in parallel with arterial pressure. Phasic CBV signals obtained in conscious rats were similar to those observed in anesthetized animals. Intravenous infusion of dipyridamole (0.5-3 mg.kg-1 x mg-1) produced a dose-dependent increase in CBV and decrease in coronary vascular resistance in conscious unrestrained rats 7 days after placement of the probe. Light microscopic review of cardiac tissue from instrumented rats revealed minimal epicardial reaction (fibrin deposition) restricted to the immediate area of the probe without distortion of the coronary architecture, edema, inflammation, or necrosis compared with controls. Heart weight-to-body weight ratios of instrumented rats were also not different from those of control rats. This study describes the first technique by which CBV can be measured continuously in chronically instrumented rats.

In utero cleft palate repair in the ovine model.

Cleft lip and palate defects assume many forms from mild to severe, but all may be associated with abnormal craniofacial development. Even the most expert and sophisticated methods of surgical repair are followed by scar contraction and fibrosis, which result in skeletal defects, dental abnormalities, cosmetic disfigurement, and speech impairment. Recent clinical and experimental observations that fetal cutaneous wounds heal without scarring are of great potential interest in the management of cleft lip and palate. The objective of this study was to investigate the effect of prenatal repair of iatrogenically produced cleft palate on scar formation in the fetal lamb model. Ten ewes were operated on ranging in gestation from 70 to 133 days. Fifteen lambs were studied (nine cleft palates produced and repaired in utero; one cleft produced in utero and not repaired, four normal, unoperated palates; and one cleft palate produced and repaired 1 week postnatally). The lambs were delivered normally at 145 to 147 days gestation and maintained with the ewe until 1 month of age. The lambs were euthanized, and the surgical area of the palates studied grossly and histologically. Animals operated at 112 days or later in gestation exhibited scars both clinically and histologically. The animals that had cleft palate produced and repaired at 70 days gestation did not have a visible palatal scar at 1 month of age. Histologically, there was evidence of minimal scarring without disruption of normal architecture. Studies are underway to determine the impact of reduced scarring on craniofacial growth after palatal repair during mid gestation in the ovine model.

Treatment of severe cardiac allograft rejection with extracorporeal photochemotherapy.

Two patients were treated with photopheresis for marked cardiac allograft rejection with hemodynamic compromise that had become unresponsive to standard therapy. Multiple episodes of rejection had occurred, and initial response to standard therapy was favorable. However, progressive deterioration was documented by serial endomyocardial biopsies, fever, congestive heart failure, and abnormal cardiac catheterization findings. In the absence of retransplantation, death seemed imminent. Photopheresis was begun. Both patients received oral 8-methoxypsoralen and > or = 5 x 10(9) mononuclear cells were collected, treated with ultraviolet light A for 1.5 hours, and were reinfused. One procedure was performed weekly x4 and then monthly x5. Responses were striking with rapid loss of fever, improvement in exercise tolerance, normalization of cardiac hemodynamics, and improvement in endomyocardial biopsies. Although our experience with these two patients is anecdotal, photopheresis merits further study as treatment for severe cardiac allograft rejection.