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.

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.

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.

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.

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.

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.

Nitinol intravascular stent: results of preclinical evaluation

PURPOSE

To test an expandable nitinol intraluminal stent for hoop strength, biocompatibility, corrosion resistance, and patency.

MATERIALS AND METHODS

Forty-four stents were implanted in the iliac arteries of 22 sheep. Follow-up was performed with angiography and histologic examination for up to 6 months.

RESULTS

All but one stent remained widely patent during the follow-up period. Two stents in two sheep were placed incorrectly early in the study; these sheep were not followed up. Hoop strength was found to be superior to that of a similar, commercially available, self-expanding stent. Minimal corrosion was seen at 6 months, and the stent appears to be biocompatible. The stent has good radiopacity and deploys with minimal foreshortening.

CONCLUSION

The stent can be reliably and safely deployed in the vascular system. Clinical trials in humans are warranted.

Scanning electron microscopic distinction of pleural mesotheliomas from adenocarcinomas

Cases of mesothelioma and adenocarcinoma involving pleura were examined by light and scanning electron microscopy utilizing H & E stained slides of paraffin-embedded material. Areas of interest were identified and isolated, and the coverslips were removed. The slide fragments were mounted on scanning electron microscopy stubs and coated with gold for 45 sec. Cases were examined in a blinded manner. Microvilli were readily identified by scanning electron microscopy with preservation of morphologic detail through the processing and staining steps required for light microscopy. The length and diameter of 20 microvilli were measured from each tumor. The mean length:diameter ratio for the mesotheliomas (n = 7) was 19.7:1 (range 13.7-23.5:1), and for the adenocarcinomas (n = 7), 2.5:1 (range 1.3-4.1) (P < 0.0005). Correlative transmission electron microscopy was performed on "scanned" specimens, and length:diameter ratios were generated. This technique has utility in distinguishing mesothelioma from adenocarcinoma. It is especially useful when glutaraldehyde-fixed, plastic-embedded tissue is not available for transmission electron microscopy. Additionally, scanning electron microscopy allows more extensive examination than transmission electron microscopy and is far less limited by section thickness and tangential sectioning artifact.

Amounts of angiotensin-converting enzyme mRNA reflect the burden of granulomas in granulomatous lung disease

A number of granulomatous lung diseases, including sarcoidosis, are associated with an increase in angiotensin-converting enzyme (ACE) activity. To evaluate whether the amount of ACE activity reflects the burden of granulomas, we used an animal model of granulomatous lung disease caused by injecting killed Mycobacterium butyricum intravenously into mice after a primary intracutaneous injection with Freund's complete adjuvant. In this model, essentially all of the granulomas are present in the lung. RNA was isolated from one lung and assayed for ACE mRNA. The other lung was evaluated histologically; the area of lung occupied by granulomas was determined by morphometry. We found that total lung RNA and RNA specific for ACE increased in close correlation with the area of granulomas. These findings provide direct evidence that the amount of ACE activity in granulomatous disease reflects the total burden of granulomas. This may be a useful model to further evaluate ACE regulation in granulomatous lung disease.

Occurrence of melanin in pheochromocytoma

Melanin or a melanin-like pigment was observed in six of 19 pheochromocytomas. The intracellular pigment was Fontana-positive, bleach-labile dark brown to black material and distinct from coincidental hemosiderin and lipochrome. Ultrastructural components of the pigmented tumors include melanosomes and premelanosomes. Two patients with pigmented tumors had associated von Hippel-Lindau syndrome, and one had neurofibromatosis. The occurrence of melanin and melanosomes in pheochromocytoma has not been previously reported in the English literature. It is probably a reflection of the neural crest origin of this neoplasm.

Incidental prostate adenocarcinoma in a thirty-year-old Native American

We report a case of prostatic adenocarcinoma in a thirty-year-old Native American. The tumor was an incidental autopsy finding. We speculate on the biological and clinical significance of prostate tumors in young males.

Histological and angiographic effects of a pulsed holmium:YAG laser in normal and atherosclerotic human coronary arteries and aorta

OBJECTIVE

The aims were (1) To determine the histological and angiographic effects of holmium:YAG laser energy delivered through clinical multifibre laser catheters on fresh cadaveric coronary arteries; and (2) to relate the placement of optical fibres in the catheter to patterns of tissue ablation in cadaveric aorta.

METHODS

Eight fresh cadaveric hearts and segments of aorta were used. Hearts were mounted on a new pressure perfusion device. The laser catheter was delivered over a guidewire in the lumen until it met an area of resistance. The coronary artery lumen was perfused at approximately 100 mm Hg mean pressure. These arterial areas were identified on angiography, marked, and then exposed to laser energy in the range 600-3000 mJ.mm-2. Normal and atherosclerotic areas of fresh cadaveric aortic strips were exposed to increasing laser energies using either constant or increasing fluence. Coronary arteries were pressure perfused with formalin for 18-24 h at 100 mm Hg mean pressure, and aortic strips were immersed in 5% formalin. Light and scanning electron microscopy studies were carried out.

RESULTS

There were no perforations or dissections by angiography in the fresh coronary arteries. One of 15 normal coronary artery segments and 10 of 16 of the pressure perfused, fixed, atherosclerotic coronary artery segments showed thermal changes associated with atherosclerotic plaque ablation. In aortic tissue, thermal effects extended 0 to 0.6 mm lateral to the ablated crater. Acoustic effects were seen only in the aortic strips after ablation at fluences > 1000 mJ.mm-2. The "dead spaces" around the optical fibres in the catheter resulted in significant amounts of coagulated tissue fragments remaining in the crater.

CONCLUSIONS

Holmium:YAG laser energy delivered through multifibre catheters ablated atherosclerotic tissue in coronary arteries with minimal damage to the normal walls. The cadaveric coronary artery perfusion apparatus is useful for assessing catheter delivery and mobility and the effects of laser energy on the coaxially orientated normal and atherosclerotic coronary arterial wall.

Diagnosis of pulmonary arteriovenous malformation by ultrafast chest computed tomography in Rendu-Osler-Weber syndrome with cerebral ischemia--a case report

Pulmonary arteriovenous malformations occur in 15-20% of patients with Rendu-Osler-Weber syndrome and can be the source of paradoxical emboli causing cerebral ischemia, septic emboli leading to brain abscesses, or polycythemia causing hyperviscosity and cerebral ischemia. The diagnosis of these malformations may be elusive, since classic clinical or radiologic findings may be absent in some patients. The authors report a patient with Rendu-Osler-Weber syndrome with cerebral ischemia who had normal findings from a pulmonary examination and chest roentgenogram. An ultrafast computed tomography scan of the chest demonstrated, however, a pulmonary arteriovenous malformation in the right upper lobe that was successfully resected. Ultrafast computed tomography of the chest is a relatively noninvasive method of screening for a pulmonary arteriovenous malformation in a patient with Rendu-Osler-Weber syndrome and otherwise unexplained neurologic symptoms.

Airway injury in swine confinement workers

OBJECTIVE

To determine whether work-related respiratory symptoms are indicative of underlying lung disease among swine confinement workers and, if so, to identify whether respiratory changes were more indicative of airway or of interstitial lung injury.

DESIGN

Nested case-control study within a population-based longitudinal study.

SETTING

University hospital.

PARTICIPANTS

Study participants were randomly selected from a group of 207 swine confinement workers followed longitudinally. Of these, 43 workers with respiratory symptoms were identified, and 31 were randomly selected for inclusion in this study. Three control groups (swine confinement workers, neighbor farmers, and blue collar workers) without work-related respiratory symptoms were frequency-matched by age, sex, and smoking status to the symptomatic swine confinement workers.

MEASUREMENTS

Spirometry and lung volumes, diffusing capacity of carbon monoxide, chest radiograph, methacholine airway challenge, and bronchoalveolar lavage were done. An endobronchial biopsy was done in the last 27 participants evaluated.

RESULTS

Although spirometric measures of airflow were similar between the symptomatic swine confinement workers and the three control groups, swine confinement cases were found to have significant elevations in residual volume (126.5 +/- 28.2 L) when compared to swine confinement controls (115.4 +/- 38.4 L; P less than or equal to 0.05), neighborhood farmer controls (101.1 +/- 29.4 L; P less than or equal to 0.005), and blue collar controls (106.4 +/- 30.4 L; P less than or equal to 0.05). Swine confinement cases also had an enhanced airway response to inhaled methacholine and had thickening of the epithelial basement membrane of the lobar bronchi. No parenchymal injury was observed in the swine confinement cases.

CONCLUSIONS

Our findings suggest that swine confinement workers who have work-related respiratory symptoms are at risk for airway, but not parenchymal, lung injury, and that spirometry may not accurately reflect the extent of airway injury.

Extraskeletal myxoid chondrosarcoma of the pleura. Report of a case clinically simulating mesothelioma

A primary extraskeletal myxoid chondrosarcoma of the pleura that clinically mimicked a malignant mesothelioma in a 66-year-old man with a history of asbestos exposure is described. Although exceedingly rare in this location, the characteristic histologic features, immunohistochemical reactivities, and ultrastructural features support the diagnosis of extraskeletal myxoid chondrosarcoma. Many ferruginous (asbestos) bodies consistent with the exposure history were found in the lung tissue sections and confirmed by energy-dispersive spectrometry. This case demonstrates an unusual pleural primary neoplasm associated with asbestos.

Lipogranulomas and gold in the liver in rheumatoid arthritis

Liver biopsies have been performed routinely as part of a protocol to evaluate methotrexate therapy in severe rheumatoid arthritis. All patients in the study had failed standard medical therapy, including gold treatment. Twenty-three of 41 patients (56%) had well-formed lipogranulomas (LGs) in the lobules, compared with an incidence of approximately 5% in our general biopsy population. Twenty-seven of 41 patients (66%) had a unique pigment in their livers. In 20 of these, the pigment was in LGs; in the seven patients with pigment not associated with lobular LG, it was found in lipid droplets in portal triads. The pigment varied from irregular pale brown granules slightly larger than those of hemosiderin, to smaller black round granules. Lipogranuloma-associated pigment of this type is an unusual finding, reminiscent of argyria. There was a variable appearance upon polarization, the black granules at times being strikingly refractile. There was a positive correlation between the prominence of LG and the quantity of pigment. The pigment resembled that described with gold deposition in other tissues. Radiographic microanalysis of both brown and black granules was performed in three cases. Characteristic spectra (energy-dispersive spectroscopy) demonstrated the presence of gold in each case. Silver was not identified. The high incidence of LG may reflect the frequent administration of gold in an oily vehicle. Gold may remain trapped in the liver for a prolonged time. Thus far, we have not detected any adverse effect from the presence of LG-associated gold.

Ultrafast computed tomography in experimental pulmonary embolism

Computed tomography (CT) has proven useful in the diagnosis of central pulmonary embolism; however, its ability to detect peripheral emboli has not been established. The authors evaluate the usefulness of ultrafast CT (UFCT) in detecting experimental peripheral pulmonary emboli. Three Gelfoam emboli measuring 0.7 x 1.5 cm were introduced into the pulmonary arteries of each of seven dogs, and contiguous, 3-mm, axial UFCT images from the lung apex to the base were obtained after the administration of a contrast bolus. After scanning, the dogs were killed, and the locations of the emboli were determined by a pulmonary pathologist blinded to the imaging results. Concomitantly, the locations of the emboli on the UFCT images were determined by consensus of three chest radiologists blinded to the autopsy results. All 21 emboli were identified on UFCT images; the locations of the emboli corresponded exactly with the autopsy findings. The authors conclude that UFCT can reliably detect Gelfoam emboli in second- to fourth-division pulmonary vessels. Further studies are needed to determine if in vivo blood clots can be similarly visualized.

Black thyroid: a pitfall for aspiration cytology

Black thyroid discoloration following long-standing use of minocycline has been reported. Morphologic findings of aspiration cytology of these lesions was first reported from The Ohio State University. This abstract describes a second case of black thyroid that was preceded by aspiration cytology. In both cases, thyroidectomies were performed based on "indeterminate" fine-needle aspiration cytology (FNAC). Degenerative changes in follicular epithelial cells in black thyroid causes nuclear hyperchromasia and chromatin clumping, which may be mistaken for neoplasia. Pigment present in follicular epithelial cells and macrophages may be obscured by pigments with similar microscopic appearances, such as hemosiderin. A clinical history of the chronic use of a tetracycline derivative should alert the pathologist to the possibility of black thyroid. Diagnosis may be made by applying special stains on the cell block. The pigment stains with Melanin stain (Fontana) and bleaches with potassium permanganate. In the light of increasing use of FNAC of the thyroid gland and the large number of patients who received tetracycline therapy in the last two decades, it is likely that some practicing cytopathologists may experience this pitfall.

Correlative light and scanning electron microscopy of intestinal giardiasis, cryptosporidiosis, and spirochetosis

Cases of intestinal giardiasis, spirochetosis, and cryptosporidiosis were examined by scanning electron microscopy (SEM) using hematoxylin and eosin (H&E)-stained tissue sections from which the coverslips were removed and the sections coated with gold. The technique is simple and reliably provides excellent morphologic detail that is preserved in the deparaffinized 4 microsections. We present examples of nine intestinal parasites examined in this manner and compare this technique with standard H&E staining and special stains with regard to relative costs, turnaround time, labor input, and morphologic preservation. Scanning electron microscopy is a useful adjunct in providing confirmatory evidence in the diagnosis of intestinal giardiasis, spirochetosis, and cryptosporidiosis.

Glial fibrillary acidic protein expression in pleomorphic adenoma, chordoma, and astrocytoma. A comparison of three antibodies

Glial fibrillary acidic protein (GFAP) is a major constituent of glial cytoplasmic intermediate filaments. Glial fibrillary acidic protein expression has been accepted as a marker of astroglial differentiation or origin. However, GFAP expression has been demonstrated in a variety of normal and neoplastic tissues outside the central nervous system, including pleomorphic adenomas, chordomas, bone, and cartilage. It has been postulated that coexpression of GFAP and vimentin in neoplastic myoepithelial cells in pleomorphic adenomas reflects early chondroid differentiation. Glial fibrillary acidic protein expression in chondromyxoid and chordoid tumors was studied in formaldehyde solution-fixed, paraffin-embedded sections of 20 pleomorphic adenomas and 10 chordomas by the immunoperoxidase method with the use of commercially available monoclonal (n = 2) and polyclonal (n = 1) antibodies. All pleomorphic adenomas and chordomas demonstrated expression of GFAP with the use of the polyclonal antibody (Biomeda Corp [Foster City, Calif]). Variable expression of GFAP was present in 90% (18/20) and 70% (14/20) of pleomorphic adenomas, and in 20% (2/10) and 0% of chordomas, with the use of the two monoclonal preparations (Dakopatts [Glostrup, Denmark] and BioGenex Laboratories [San Ramon, Calif]), respectively. Normal brain tissue and eight astrocytomas were used as "controls" to compare staining intensity and quality between the polyclonal and monoclonal anti-GFAP antibodies. Glial fibrillary acidic protein positivity with the polyclonal antibody was more intense than that with either monoclonal antibody despite similar (congruent) distributions of tumor cell types that were stained in control brain and astrocytoma tissues. The GFAP polyclonal antibody was more frequently immunoreactive than the monoclonal antibodies, particularly in cells that exhibited chondroid differentiation. These findings may have practical application in surgical pathology.

Immunohistochemical distinction of classic and chondroid chordomas

Chondroid chordomas are cartilage-rich neoplasms, most often located in the spheno-occipital region, that have a better prognosis than classic chordomas. The immunohistochemical features of 19 classic and chondroid chordomas were studied retrospectively using avidin-biotin-complex (ABC) immunoperoxidase histochemistry on formalin-fixed, paraffin-embedded tissue. Of the 19 tumors, all located in the spheno-occipital region, 5 exhibited predominantly chondroid morphologic features. The 14 classic chordomas showed the following pattern of antigen expression (percent of tumors positive): epithelial membrane antigen (EMA) 100%, AE 1/3 (a "cocktail" of monoclonal antibodies directed against low and high molecular weight epidermal cytokeratins) 100%, DP keratin (DPK) 100%, vimentin 100%, S100 86%, neuron specific enolase (NSE) 100%, carcinoembryonic antigen (CEA) 57%, and HMB-45 (an anti-melanoma-associated antibody) 57%. The five chondroid chordomas exhibited the following pattern: EMA 0%, AE 1/3 0%, DPK 0%, vimentin 100%, S100 100%, NSE 100%, CEA 0%, and HMB-45 0%. The focal, weak HMB-45 positivity (performed on the index case because of a clinical concern of metastatic melanoma) seen in 57% of the classic chordomas is a previously unreported finding. This finding suggests either that classic chordomas are capable of HMB-45 expression or that this antibody has broader reactivity than previously recognized. The lack of cytokeratin, EMA, and CEA expression by the chondroid chordomas is similar to chondrosarcomas as reported in the literature and dissimilar to the classic chordoma group. These immunohistochemical findings suggest that chondroid chordomas may more validly be classified as low grade chondrosarcomas.

Mica-associated pulmonary interstitial fibrosis

We present the clinical and biopsy findings of a 63-yr-old white male with interstitial pulmonary fibrosis and a long history of extensive exposure to mica while working in the rubber industry. The patient presented 30 yr after the initial exposure with complaints of progressive shortness of breath and a chronic nonproductive cough. Pulmonary function testing revealed restrictive lung function with a mild reduction in the total lung capacity (80% of predicted) and a moderate-to-severe reduction in the diffusing capacity of carbon monoxide (50% of predicted). The chest radiogram and high-resolution chest CT scan showed diffuse fibrosis and focal honeycombing involving the upper and lower lung zones bilaterally. Bronchoalveolar lavage revealed 20% neutrophils in the lavage fluid with abundant rectangular flaking crystals. Open-lung biopsy exhibited extensive fibrosis and architectural remodeling with abundant sheets and fragments of engulfed polarizable crystalline material. Energy-dispersive spectroscopy and electron diffraction studies confirmed the material to have the features of mica. Asbestos and other silicates were not identified. The documentation of prolonged exposure to mica, the clinical and radiographic features of severe interstitial fibrosis, and the histopathologic delineation of the interstitial lesion, including spectroscopic and crystallographic verification of crystalline mica, support the causal relationship between mica and interstitial fibrosis.

Pleomorphic melanoma mimicking sarcoma

Malignant melanoma may display a wide variety of unusual morphologic patterns that simulate unrelated neoplasms. The diagnostic approach to such complex and morphologically divergent lesions requires thorough and extensive scrutiny not only by routine light microscopy, but also by immunohistochemical and ultrastructural evaluation. We have reported the case of a patient with a mass on the heel exhibiting complex morphology that illustrates the value of such a systematic approach.

Evidence that epidermal alloantigen Epa-1 is an immunogen for murine heart as well as skin allograft rejection

Epa-1 is a non-H-2 mouse alloantigen defined by MHC-restricted, CD8+ cytotoxic T cells. In vitro it is a strong determinant for the lysis of epidermal cells, fibroblasts, and macrophages but not lymphocytes, and in vivo it functions as a target for skin allograft rejection and cutaneous graft-versus-host reactions. Genetically, Epa-1 appears to be the nonpolymorphic manifestation of a loss mutation. The establishment of C3H.Epa-1 (Epa), an Epa-1+ congenic strain on the Epa-1- C3H/HeJ (C3H) inbred strain background, facilitated the investigation of the role of Epa-1 in skin and heart allograft rejection. C3H females and males rejected first-set Epa skin grafts with median survival times (MSTs) of 20 and 30 days, respectively. However, there was a strong factor of immunization, because all second-set skin allografts were rejected by hosts of both sexes within 10 days. In contrast, all Epa hosts of both sexes permanently accepted C3H skin allografts, consistent with Epa-1 arising from a loss mutation. C3H hosts of both sexes rejected primarily vascularized first-set Epa heart allografts in similar tempo to first-set Epa skin allografts, with MSTs of about 30 days. However, in contrast to the accelerated rejection of skin allografts, sensitized C3H hosts rejected Epa heart allografts in chronic fashion, with some transplants showing very prolonged survival. Thus, Epa-1 is a relatively strong determinant of skin allograft rejection but a weaker determinant of heart allograft rejection.

Sponge artifact in biopsy specimens

We describe a sponge-induced artifact in histologic sections of small biopsy specimens. The artifacts are angulated, often triangular holes within the tissue. They appear to be introduced as individual sponge barbs become embedded in the perimeter of biopsy specimens during tissue processing. The artifact is generally of little importance, but in certain specimens, such as needle biopsies of the kidney or liver, it may occasionally obscure important information. Other methods, such as lens paper wrapping, may be superior in these situations. The utility of the tissue cassette sponge, in most situations, outweighs the artifact.

Peripheral atherectomy: experimental results with a new device

The size of present rotational atherectomy devices is limited in part by a tendency to produce vessel torsion. The authors designed and investigated a large-bore rotational atherectomy device for peripheral atherectomy in a single pass without significant torsion. A plaque was retrieved from 36 of 40 cadaveric iliac arteries. The mean plaque size was 8.4 x 3.9 mm, and the average number retrieved per artery was two. Thirty of 34 severely calcified arteries were treated successfully. Effluent study revealed no distal embolization; however, six perforations and four dissections occurred. Preliminary results suggest that a cutting surface with a relatively large diameter can be designed to be effective without producing vessel torsion. Changes in future designs will include added flexibility and expandable cutting surfaces to enhance safety and minimize entry diameter.

Thermal balloon angioplasty in a canine model: preliminary results

Preliminary results suggest that thermal balloon angioplasty (BA) may produce plaque welding, decreased elastic recoil, and increased luminal caliber. The authors report results of a simple method of thermal BA in a canine model. Seven mongrel dogs (15-25 kg) underwent conventional BA of each iliac artery with balloons that were 1-2 mm larger than the vessel lumen. The balloons were then perfused with a mixture of saline and contrast material at either 25 degrees C (control) or 100 degrees C for 1 minute. Compared with baseline measurements, thermal BA produced greater lumen enlargement (+16.7%) than control BA (+3.4%) immediately after the procedure (P less than .05). This trend persisted in vessels studied after a delay of 2, 4, or 12 weeks. Histologic sections from specimens studied after a delay demonstrated intimal hyperplasia in both the thermally treated and control arteries. Medial sclerosis was consistently seen in the thermally treated arteries. The authors conclude that thermal BA results in immediate and delayed increases in arterial diameter compared with conventional BA due to decreased elastic recoil and medial sclerosis.

Nonpigmented papillary carcinoma in a black thyroid gland

A case of papillary thyroid carcinoma occurring in a 27-year-old man with black thyroid syndrome is reported. The tumor, in contrast to the remaining thyroid, was not pigmented. The significance and potential utility of the differential pigmentation are discussed.

Plaque modification with tetracycline: enhanced tissue ablation with the excimer laser

Tetracycline has been shown to collect selectively in atherosclerotic plaque and is a known photosensitizing agent. To determine if tetracycline enhances the photoablative effects of the ultraviolet xenon-fluorine excimer laser, the authors exposed four cadaveric aortic samples to tetracycline and four to only normal saline. Ninety-three sites in the samples were subjected to laser energy and analyzed with light microscopy for crater depth and width and for degree of thermal injury. Forty-three of the sites were histologically normal, and 50 were atherosclerotic. Crater depth did not differ significantly in atherosclerotic and normal sites not exposed to tetracycline. Atherosclerotic sites exposed to tetracycline showed significantly deeper craters compared with those in normal, exposed sites. The effects of tetracycline exposure and histologic characteristics (normal vs atherosclerotic) on crater width and thermal injury were independent and additive. When the excimer laser is used for treatment, tetracycline can definitely enhance atherosclerotic plaque ablation.

Selective catecholamine depletion of structures along the ventral lamina terminalis: effects on experimentally-induced drinking and pressor responses

Ablation of the periventricular tissue of the anteroventral third ventricle (AV3V) or injection of the chemical neurotoxin, 6-hydroxydopamine (6-OHDA), into the structures along the ventral lamina terminalis will produce deficits in drinking and pressor responses to exogenous angiotensin II (ANG II). Centrally-applied 6-OHDA has been shown to result in widespread depletions of both adrenergic (i.e. both noradrenaline and adrenaline-containing) and dopaminergic neurons. Questions arise, therefore, as to whether a dopaminergic or adrenergic depletion is critical and the locus where reductions must occur. The present experiment was designed to investigate the specificity of the effects of 6-OHDA administration into lamina terminalis-associated structures on ANG II-induced drinking and pressor responses. The nature of the depletion was manipulated with desmethylimipramine (DMI), a drug which blocks the uptake of 6-OHDA into adrenergic but not dopaminergic nerve terminals and thereby spares adrenergic elements. The experimental results indicate that 6-OHDA administration into structures of the ventral lamina terminalis produced ANG II response deficits and marked reductions in catecholamine histofluorescence in the regions of the injection sites. In contrast, pretreatment with DMI protected against the 6-OHDA-produced functional deficits and minimized the effects on histofluorescence. These findings are consistent with the interpretation that adrenergic but not dopaminergic neurons must be present in the structures of the ventral lamina terminalis in order to elicit normal angiotensin-induced drinking and pressor responses.

Localized injections of 6-hydroxydopamine into lamina terminalis-associated structures: effects on experimentally induced drinking and pressor responses

Electrolytic lesions of tissues surrounding the anteroventral third ventricle (AV3V) or injections of the chemical neurotoxin, 6-hydroxydopamine (6-OHDA) into the lateral cerebral ventricles result in virtually identical deficits in response to a variety of dipsogenic and pressor challenges. These observations have led to the hypothesis that the integrity of catecholamine (CA) projections into the AV3V region is a prerequisite for elicitation of these thirst and blood pressure responses. This hypothesis was tested in 6-OHDA-injected rats following protocols designed to deplete CA's in discrete structures associated with the lamina terminalis. Post-injection response deficits, coupled with histofluorescent assessments of CA depletions in specific anterior forebrain nuclei, support the stated hypothesis. In addition, the findings indicate that thirst deficits to systemic as well as central dipsogenic challenges are both selective and dissociable and that 6-OHDA lesions of any of the more ventrally situated target nuclei result in significantly attenuated blood pressure responses to centrally injected angiotensin II.

Warfarin-related purple toes syndrome and cholesterol microembolization

The "purple toes syndrome" is a rare complication of oral anticoagulant therapy. Four patients who presented with "purple toes syndrome" several weeks after warfarin therapy was initiated are described. The diagnosis of cholesterol microembolization was made by biopsy in three cases. Malignant hypertension and renal failure developed in two patients who died within three to six months of onset of purple toes. Postmortem examination in one of these patients showed widespread cholesterol microembolization. Renal failure has not developed in the other two patients, who are doing well. These biopsy and autopsy results suggest that the warfarin-related "purple toes syndrome" is due to cholesterol microembolization.

Fetal noradrenergic transplants into amine-depleted basal forebrain nuclei restore drinking to angiotensin

6-Hydroxydopamine-induced catecholamine denervations in the organum vasculosum of the lamina terminalis and the median preoptic nucleus attenuate drinking responses to systemic angiotensin II (ANG II) injections. Transplanting catecholamines in these nuclei using fetal noradrenergic (NE) cell suspension restores ANG II-elicited thirst. These results emphasize the functional importance of NE neuronal systems in nuclei of the anteroventral third ventricle (AV3V) in mediating ANG II-induced drinking behaviors.

Black thyroid syndrome: exaggeration of a normal process?

Coal-black thyroid discoloration usually is identified in patients receiving chronic minocycline therapy. This report concerns the use of light microscopic, electron microscopic, and energy dispersion spectroscopy of thyroid pigments in three separate situations: minocycline-associated black thyroid; idiopathic black thyroid; and normally pigmented thyroid glands. One of the pigments, which is found in each situation, is best described as neuromelanin. This melanin pigment, like lipofuscin, appears to accumulate with advancing age. Pigment accumulation, therefore, is a normal process in the thyroid gland. Accelerated pigment accumulation occurs with minocycline therapy but can uncommonly be seen without associated minocycline treatment. Possible mechanisms for the development of these pigments in normal and black thyroid glands are discussed. Minocycline-associated pigment is also described in substantia nigra and atherosclerotic plaques.