[Comparison of radiological and clinicopathological features of craniofacial fibro-osseous lesions]

Objective: To investigate the clinicopathological and radiological features of benign fibro-osseous lesion (BFOL). Methods: Sixty-five cases of craniofacial BFOL, eight cases of peripheral ossifying fibroma (POF) and one case of low-grade central osteosarcoma diagnosed at Sichuan Provincial People's Hospital between January 2010 and March 2019 were collected. The clinicopathologic features, hematoxylin-eosin and immunohistochemical (IHC) staining and radiographic features were analyzed. MDM2 gene amplification was detected by FISH in difficult borderline cases. Results: This cohort of BFOLs included 50 cases of fibrous dysplasia (FD), 12 cases of ossifying fibroma (OF), and three cases of juvenile psammomatoid ossifying fibroma (JPOF). The average ages of patients with FD,OF and JPOF were 31.7, 39.2 and 26.0 years respectively. The male to female ratio was 1.0∶1.8.The average age of POF was 47.0 years, with male to female ratio of 1∶7. Patient of low-grade central osteosarcoma was a 48-year-old man. Twenty-seven cases of FD were located in the jaw, and 23 cases were in other craniofacial bones. Nine cases of OF were located in the jaw, and three cases were in the nasal cavity. Two cases of JPOF were in the nasal sinus, and one was in the jaw. All POF were located in the gingiva, and low-grade central osteosarcoma was located in the mandible. The imaging features of FD were luffa-like or ground-glass like signal shadows with poorly defined borders with expansion. OF had clear borders or sclerosing margins. Both JOF and low-grade central osteosarcoma were expansile intraosseously and with focally invasive nodular masses with ground-glass like signal shadows; and POF showed soft tissue mass with bone formation. Histological features of BFOLs showed mixed fibrous and irregular osteoid lesions. FD had no clear relationship with the host bone and no osteoblasts surrounded the bone trabeculae. Osteoblasts rimming was found in OF, and the boundaries of the host bone were clear. JPOF and low-grade central osteosarcoma infiltrated the host bone focally, and the latter showed mild cellular atypia. MDM2 amplification was detected in low-grade central osteosarcoma. Conclusions: BFOLs are a group of fibro-osseous lesions with similar morphology in the head and neck and face, but their clinical features and prognosis are different; and their imaging and histological characteristics are also slightly different. Attentions should be given to the combination of clinical, imaging and pathologic features of BFOLs, especially the differential diagnosis between BFOLs and low-grade central osteosarcoma. Molecular detection could be used to assist the diagnosis in difficult cases.

Construction of ultrathin MnO2 decorated graphene/carbon nanotube nanocomposites as efficient sulfur hosts for high-performance lithium–sulfur batteries

Lithium–sulfur batteries are attracting significant attention due to their high theoretical specific capacity and low cost. However, their applications are hindered by the poor conductivity of sulfur and capacity fading caused by the shuttle effect. Here, ultrathin manganese dioxide decorated graphene/carbon nanotube nanocomposites are designed as sulfur hosts to suppress the shuttle effect and improve the adsorption efficiency of polysulfides. The graphene/carbon nanotube hybrids, with extraordinary conductivity and large surface area, function as excellent channels for electron transfer and lithium ion diffusion. The ultrathin manganese dioxide nanosheets enable efficient chemical interaction with polysulfides and promote the redox kinetics of polysulfides. As a result, an ultrathin manganese dioxide decorated graphene/carbon nanotube sulfur composite with high sulfur content (81.8 wt%) delivers a high initial specific capacity of 1015.1 mA h g⁻¹ at a current density of 0.1C, high coulombic efficiency approaching 100% and high capacity retention of 84.1% after 100 cycles. The nanocomposites developed in this work have promising applications in high-performance lithium–sulfur batteries.

Ultrathin MnO₂ nanosheets and nano size sulfur particles distributed uniformly on the surface of G/CNT hybrids, which exhibit high rate performance and long-term cycling performance.

Fluorinated graphene/sulfur hybrid cathode for high energy and high power density lithium primary batteries

Fluorinated graphene (FG)/sulfur hybrid cathode with monoclinic sulfur enables the lithium primary battery exhibiting excellent capacity and rate performance.

Facile synthesis and characterization of ultrathin δ-MnO2 nanoflakes

Ultrathin δ-MnO₂ nanoflakes were synthesized via a facile route and present excellent specific capacitance and good cycling stability.

A phosphotungstic acid self-anchored hybrid proton exchange membrane for direct methanol fuel cells

DMFCs based on a phosphotungstic acid self-anchored membrane exhibit comparable performance with that of Nafion212.

Can bicarbonate replace phosphate to improve the sustainability of bioelectrochemical systems for H2production?

Large (80%) replacement of PO₄³⁻with HCO₃⁻is feasible to maintain the current density and improve the sustainability of MEC.

A gemini quaternary ammonium poly (ether ether ketone) anion-exchange membrane for alkaline fuel cell: design, synthesis, and properties

To reconcile the tradeoff between conductivity and dimensional stability in AEMs, a novel Gemini quaternary ammonium poly (ether ether ketone) (GQ-PEEK) membrane was designed and successfully synthesized by a green three-step procedure that included polycondensation, bromination, and quaternization. Gemini quaternary ammonium cation groups attached to the anti-swelling PEEK backbone improved the ionic conductivity of the membranes while undergoing only moderate swelling. The grafting degree (GD) of the GQ-PEEK significantly affected the properties of the membranes, including their ion-exchange capacity, water uptake, swelling, and ionic conductivity. Our GQ-PEEK membranes exhibited less swelling (≤ 40 % at 25-70 °C, GD 67 %) and greater ionic conductivity (44.8 mS cm(-1) at 75 °C, GD 67 %) compared with single quaternary ammonium poly (ether ether ketone). Enhanced fuel cell performance was achieved when the GQ-PEEK membranes were incorporated into H2 /O2 single cells.

Nonionic surfactant greatly enhances the reductive debromination of polybrominated diphenyl ethers by nanoscale zero-valent iron: mechanism and kinetics

Nanoscale zero-valent iron (nZVI) has been considered as an effective agent for reductive debromination of polybrominated diphenyl ethers (PBDEs). But the high lipophilicity of PBDEs will hinder their debromination owing to the inefficient contact of PBDEs with nZVI. In this study, different ionic forms of surfactants were investigated aiming to promote PBDE debromination, and the beneficial effects of surfactant were found to be: nonionic polyethylene glycol octylphenol ether (Triton X-100, TX)>cationic cetylpyridinium chloride (CPC)>anionic sodium dodecyl benzenesulfonate (SDDBS). Except for with SDDBS, the promotion effect for PBDE debromination was positively related to the surfactant concentrations until a critical micelle concentration (CMC). The debromination process of octa-BDE and its intermediates could be described as a consecutive reaction. The corresponding rate constants (k) for the debromination of parent octa-BDE (including nona- to hepta-BDEs), the intermediates hexa-, penta-, and tetra-BDEs are 1.24 × 10(-1) h(-1), 8.97 × 10(-2) h(-1), 6.50 × 10(-2) h(-1) and 2.37 × 10(-3) h(-1), respectively.

Nernst-ping-pong model for evaluating the effects of the substrate concentration and anode potential on the kinetic characteristics of bioanode

Understanding the electron-transfer mechanism and kinetic characteristics of bioanodes is greatly significant to enhance the electron-generating efficiencies in bioelectrochemical systems (BESs). A Nernst-ping-pong model is proposed here to investigate the kinetics and biochemical processes of bioanodes in a microbial electrolysis cell. This model can accurately describe the effects of the substrate (including substrate inhibition) and the anode potential on the current of bioanodes. Results show that the half-wave potential positively shifts as the substrate concentration increases, indicating that the rate-determining steps of anodic processes change from substrate oxidation to intracellular electron transport reaction. The anode potential has negligible effects on the enzymatic catalysis of anodic microbes in the range of -0.25 V to +0.1 V vs. a saturated calomel electrode. It turns out that to reduce the anodic energy loss caused by overpotential, higher substrate concentrations are preferred, if the substrate do not significantly and adversely affect the output current.

Malignant hemangiopericytoma arising in neurofibromatosis: a case report with histological, immunohistochemical and ultrastructural studies

Subject. A 27-year-old Hispanic male with clinical manifestation of neurofibromatosis type 1 developed chronic constipation and urination difficulty along with recently increased abdominal bloating and anorexia. He also noted 40 lbs weight loss over period of 1 year. Physical and radiographic examinations revealed a large mass in the right pelvic fossa.

Results. The surgically removed tumor was demonstrated, histologically, immunohistochemically, and ultrastructurally, to be a malignant hemangiopericytoma.

Discussion.Although non-neurogenic tumors associated with neurofibromatosis have been reported in these patients, only one hemangiopericytoma case has been found in the English literature. We report here another case of this rare malignant hemangiopericytoma in a patient with neurofibromatosis.

Predicting postoperative nausea and vomiting with the application of an artificial neural network

BACKGROUND

Several medications have proved to be useful in preventing postoperative nausea and vomiting (PONV). However, routine antiemetic prophylaxis is not cost-effective. We evaluated the accuracy and discriminating power of an artificial neural network (ANN) to predict PONV.

METHODS

We analysed data from 1086 in-patients who underwent various surgical procedures under general anaesthesia without antiemetic prophylaxis. Predictors used for ANN training were selected by computing the value of chi(2) statistic and information gain with respect to PONV. The configuration of the ANN was chosen by using a software tool. Then the training of the ANN was performed based on data from a training set (n=656). Testing validation was performed with the remaining patients (n=430) whose outcome regarding PONV was unknown to the ANN. Area under the receiver operating characteristic (ROC) curves were used to quantify predictive performance. ANN performance was compared with those of the Naïve Bayesian classifier model, logistic regression model, simplified Apfel score and Koivuranta score.

RESULTS

ANN accuracy was 83.3%, sensitivity 77.9% and specificity 85.0% in predicting PONV. The areas under the ROC curve follow: ANN, 0.814 (0.774-0.850); Naïve Bayesian classifier, 0.570 (0.522-0.617); logistic regression, 0.669 (0.623-0.714); Koivuranta score, 0.626 (0.578-0.672); simplified Apfel score, 0.624 (0.576-0.670). ANN discriminatory power was superior to those of the other predicting models (P<0.05).

CONCLUSIONS

The ANN provided the best predictive performance among all tested models.

Congenital gastrointestinal pacemaker cell tumor

The interstitial cells of Cajal complex within the gut wall function as a pacemaker to direct peristalsis. Their neoplastic counterpart is the gastrointestinal pacemaker cell tumor, a spindle and/or epithelioid cell mesenchymal tumor previously known as gastrointestinal stromal tumor or incorrectly called leiomyosarcoma in some cases of older reports. Although numerous cases of gastrointestinal leiomyosarcomas have been documented in the English-language literature, no pediatric case of gastrointestinal stromal tumor or gastrointestinal pacemaker cell tumor has, to our knowledge, been recorded. Herein, we report a case of congenital gastrointestinal pacemaker cell tumor confirmed by immunohistochemistry and electron microscopy in a full-term male newborn.

Coinfection of visceral leishmaniasis and Mycobacterium in a patient with acquired immunodeficiency syndrome

We report a case of coinfection of visceral leishmaniasis and Mycobacterium avium-intracellulare in the same lesions in the small bowel and bone marrow of a 33-year-old man with acquired immunodeficiency syndrome who complained of abdominal pain and chronic diarrhea. The duodenal mucosa and bone marrow biopsy specimens showed numerous foamy macrophages packed with two forms of microorganisms that were identified histologically and ultrastructurally as Leishmania and Mycobacterium species. Visceral leishmaniasis is rarely suspected in patients residing in nonendemic countries including the United States. It should be included in the differential diagnosis for opportunistic infection in patients with acquired immunodeficiency syndrome. An appropriate travel history is important. To our knowledge, this is the first reported case showing coinfection of visceral leishmaniasis and Mycobacterium avium-intracelluulare in the same lesion in a patient with acquired immunodeficiency syndrome.

Generalized lichen nitidus: case report and literature review

Lichen nitidus is a rare condition of unknown cause, characterized by minute, flesh-colored, shiny papules occurring on the genitalia, abdomen, chest, and extremities. This disorder is most often localized, but a few cases of generalized lichen nitidus have been reported. We describe a young patient with a 1.5-year history of unremitting generalized lichen nitidus.

Kasabach-Merritt syndrome-associated kaposiform hemangioendothelioma successfully treated with cyclophosphamide, vincristine, and actinomycin D

PURPOSE

The authors introduced a successful trial of a chemotherapy regimen to treat refractory thrombocytopenia and pain caused by a rare kaposiform hemangioendothelioma that had been refractory to corticosteroids.

PATIENT AND METHOD

A 6-year-old Latina girl with diffuse petechiae, constant pain and edema in her right lower extremity, and severe thrombocytopenia was brought for treatment. Physical examination revealed a large mass in the right lower extremity. The surgical specimen resected earlier in Mexico showed kaposiform hemangioendothelioma, an extremely rare vascular tumor that is frequently associated with consumptive coagulopathy and lymphangiomatosis. Corticosteroid therapy in Mexico had been ineffective in controlling the tumor size, pain, or thrombocytopenia. The patient was brought to the United States because of a rapidly enlarging tumor and intractable leg pain, causing inability to ambulate. Laboratory examinations revealed profound thrombocytopenia and evidence of consumptive coagulopathy. Because of the rapidly enlarging lesion, it was decided to give six cycles of a chemotherapy regimen consisting of vincristine, cyclophosphamide, and actinomycin D (VAC).

RESULT

The patient responded to the first cycle of chemotherapy with partial reversal of the thrombocytopenia. The additional five cycles of the same chemotherapy regimen resulted in complete resolution of thrombocytopenia and significant improvement of the pain and edema in the right lower extremity. A follow-up imaging study 9 months later revealed a marked decrease in size of the vascular tumor.

CONCLUSION

Inoperable kaposiform hemangioendothelioma unresponsive to corticosteroids can be successfully treated with chemotherapy.

Association of primary intracranial meningioma and cutaneous meningioma of external auditory canal: a case report and review of the literature

A cutaneous meningioma of the external auditory canal occurred in a 48-year-old Filipino woman who had undergone subtotal resection of a dural-based intracranial meningioma at the ipsilateral cerebellopontine angle 36 months previously. Radiologic findings demonstrated a recurrence of intracranial meningioma with surface erosion and heterogeneous densities of the mastoid bone, without extension to the area of the external auditory canal. Meningioma in the external ear canal is extremely rare. To our knowledge, there have been only two previously reported cases, both without intracranial lesion. In this case, the auditory canal lesion may represent either an ectopic meningioma arising from an arachnoid cell rest or an occult direct extension from intracranial menigioma.

Malignant melanoma in a tattoo: case report and review of the literature

Several benign and malignant lesions have occurred in tattoos, including verrucae, granulomas, allergic reactions, basal cell carcinomas, and squamous cell carcinomas. In addition, seven documented cases of malignant melanoma occurring in tattoos have been reported in the English literature. We describe another patient with malignant melanoma in a tattoo.

Disseminated coccidioidomycosis with rapid progression to effusive-constrictive pericarditis

This case reports coccidiomycosis presenting as pericarditis with tamponade rapidly progressing to effusive-constrictive pericarditis and death over 72 hours. Coccidiomycosis pericarditis is a rapidly progressing disease requiring early and complete pericardiectomy to avoid the hemodynamics of constriction. We illustrate the use of echocardiography in this case and demonstrate the histopathology. We review the literature and discuss therapy and management. Coccidiomycosis is often clinically unsuspected and unrecognized by the health care worker unfamiliar with the disease process.

Composite porosity of expanded polytetrafluoroethylene vascular prosthesis

Polytetrafluoroethylene (PTFE) prostheses were modified to produce two types of composite porosity PTFE grafts: type I--inner 60 microns/outer 20 microns and type II--inner 20 microns/outer 60 microns. These composite porosity PTFE designs were investigated for bleed through, graft healing and patency and compared with high porosity PTFE (60 microns) and standard PTFE (20 microns) grafts. The grafts were implanted into the carotid and femoral arteries of dogs and retrieved after 4, 12 and 18 weeks. Both composite porosity grafts showed significantly less bleed through than standard and high porosity grafts after reperfusion. In composite grafts, the 60-microns layer allowed fibrovascular tissue and histiocyte ingrowth from perigraft tissue, but the 20-microns layer did not. Neointima formation occurred earlier and endothelialization was more extensive in high porosity grafts, but seroma formation occurred in 25% of cases. In type I composite porosity grafts, smooth muscle cells of neointima migrated into the pores of the graft, providing a firmly anchored intima. Type II composite porosity grafts allowed better ingrowth of fibrovascular tissue at the outer layer from the perigraft tissue; however, endothelialization was not completed. Composite porosity grafts should be considered for evaluation in specific clinical situations.

Accurate coronary calcium phosphate mass measurements from electron beam computed tomograms

Precipitates of calcium phosphate in coronary arteries always indicate the presence of atherosclerosis. The mass of these precipitates is related to the severity of atherosclerosis. To determine the accuracy of electron beam computed tomographic (CT) mass estimates, we imaged 21 human hearts inside an anthropomorphic chest phantom using an Imatron C-100 electron beam CT scanner (Imatron, San Francisco, CA). We then incinerated the 63 imaged coronary arteries and weighed the mineral ash. We calculated the mass estimates from the images using an algorithm derived from a model that assumes simple radiographic properties of the coronary arteries. We also calculated the currently used coronary calcium score for each artery. Although both the mass estimates and the scores correlated with the actual mass of the incinerated specimens (r = .97 and r = .93), the correlation with the mass estimates was better (P = .02; William's test). The regression equation relating the actual mass to the mass estimates was y = 1.37 x + 14, indicating that the CT mass estimates consistently underestimate actual coronary calcium phosphate mass. We conclude that relative mass estimates using electron beam CT scanning are accurate and that both these and the currently employed calcium scores reflect the actual mass of precipitated calcium phosphate in diseased coronary arteries.

Eccentric iliac artery stenosis: a canine model for angioplasty

A canine model was developed to induce eccentric iliac artery stenosis. Lesions were induced by exposing the medial aspect of the right and left common iliac arteries in four animals to direct argon laser energy (LA). A 2.5-mm diameter side-firing laser probe was used to deliver 10 W of power in 5-s intervals. Twenty-five pulses were delivered over a 5-cm length of artery with an approximate spot size of 0.8 mm2. Selected arteries (n = 2, LA + Ca) were injected in the same laser injury site with calcium chloride (10% solution). Injections were accurately accomplished using an angioscopically guided guidewire/needle device. In all cases, the internal elastic lamina was broken with focal disruptions of the media. At 9 and 14 days, the LA (n = 3) and LA + Ca vessels (n = 1) had minimal stenoses (< 5% area reduction). These vessels contained edematous media with replacement of necrotic smooth muscle by fibrous tissue. At 23 days, the LA (n = 1) and LA + Ca (n = 1) vessels contained 22% and 33% luminal reductions, respectively, with moderate neointimal proliferation and no evidence of calcification. At 56 days the LA vessels (n = 2) contained 30 and 42% luminal area stenoses with marked neointimal hyperplasia. This preliminary data suggests that controlled arterial wall injury with LA irradiation can induce eccentric fibrointimal lesions in a canine model.

New device for visual neodymium:YAG laser prostate ablation: acute and chronic canine evaluation

This canine study (n = 6) evaluated the acute and chronic effects of Nd:YAG laser prostatectomy using a Prolase II fiber. The Prolase II device consists of a 1,000 microns quartz fiber which directs a cone of Nd:YAG laser energy, at 45 degrees to the axis of the fiber, into the prostatic urethra under direct visual guidance [visual laser ablation of prostate, (VLAP)]. Under visual guidance and saline irrigation, 60 seconds of 60 watts of laser power was delivered at 3, 6, 9, and 12 o'clock positions (14,400 J). One canine was instrumented but received no laser energy (control). One prostate was harvested acutely. The remaining four laser-treated dogs were evaluated at 6 to 16 weeks. The histopathology of acute laser effects shows areas of necrosis with loss of glandular structures and stromal edema. Surrounding this area was a zone of degenerative glandular structures extending up to 12.6 mm into the prostate. Two of the four dogs developed urinary retention at 6.5 and 9 weeks. On examination, both were found to have fibrotic strictures at the distal prostatic urethra with markedly dilated proximal prostatic urethral lumens (1.98 and 2.8 cm). Two other dogs showed no signs of urinary retention at sacrifice. Histopathology, both the 6 and 16 week laser-treated animals without urinary retention demonstrated dilated prostatic urethras with maximum cross-sectional diameters of 1.52 and 1.50 cm, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Nd:YAG laser-welded canine arteriovenous anastomoses

This preliminary report describes formation of femoral arterio-venous fistulas (n = 10) in six dogs using a 1.32-microns wavelength Nd:YAG laser welding technique. Stay sutures (6-0 polypropylene) were placed at 5-7 mm intervals along the anastomoses for vessel apposition. Delivery of laser energy through a 400-microns diameter fiber optic was controlled by a new computer-based software system. At 3 mm distance above the anastomosis, energy fluences of 110-260 J/mm2/cm length of anastomosis were used for laser welding. One or two additional hemostatic sutures were required in seven of the ten anastomoses. Flow was maintained for 1-2 hours prior to tissue harvesting. No thrombosis or delayed anastomotic failures were observed after initial welding and repair. Histologic examination revealed good apposition and adherence between wall layers and a fibrinous coagulum at the intimal junctions. Mild thermal injury of the wall was present at some anastomoses. This early investigation suggests that a 1.32 microns Nd:YAG laser welding technique can successfully create large vessel arteriovenous fistulas in the canine.

In vivo study of a high-porosity polytetrafluoroethylene graft: endothelialization, fluid leakage, and the effect of fibrin glue sealing

Standard polytetrafluoroethylene (PTFE) grafts (30-microns internodal distance, ID) (ST grafts), high-porosity PTFE grafts (90 microns ID) (HP grafts), high-porosity PTFE grafts preclotted with autogenous blood (BHP grafts), and high-porosity PTFE grafts presealed with fibrin glue (FHP grafts) were implanted in both common carotid and femoral arteries of 18 dogs. Of the three high-porosity groups, the FHP graft showed the shortest bleeding time. Seromas and/or hematomas occurred as follows: ST grafts 1, HP grafts 7 (P < .05 vs ST), BHP grafts 5 and 2 with FHP grafts. Fibrin glue was observed in all histological sections of 1-week samples, but by 4 weeks it was almost totally absorbed. No endothelialization (ET) was measurable at 2 weeks. By 4 weeks ET extended for a short distance from each anastomosis and there were no significant differences between the four graft groups. At 18 weeks, the HP, BHP, and FHP grafts showed a significant increase in ET compared with the ST graft (P < .01) but there were no significant differences between the three types of high-porosity graft. The differences in patency rates and neointimal thicknesses did not reach statistical significance. High-porosity PTFE grafts showed superior endothelialization in dogs; however, the enlarged ID of PTFE grafts increased intraoperative bleeding and postoperative seroma formation. Fibrin glue sealant controlled bleeding through the graft wall without affecting graft healing, but its sealant effect was not enough to prevent late fluid leakage.

MR imaging of Ho:YAG laser diskectomy with histologic correlation

Twelve cadaveric vertebral specimens were imaged after holmium yttrium aluminum garnet (Ho:YAG) laser diskectomy to determine the usefulness of magnetic resonance (MR) imaging in evaluating treatment outcome. The Ho:YAG laser was operated at 1.0-2.0 J per pulse, 5 Hz, and 250-microseconds pulse width. The total energy varied between 600 and 2,700 J. Two distinct patterns emerged on MR images. Tissue ablation at higher power (1.5 and 2.0 J per pulse) produced discrete signal voids that correlated with areas of laser-induced ablation identified at gross inspection. More subtle changes, characterized by a high-signal-intensity ring, were seen in the specimens lased at 1.0 J per pulse. The latter appearance corresponded to incomplete vaporization of diskal tissue, a broader zone of minimal thermal injury, and sparing of adjacent vertebral endplates. Total mass loss did not appear to be affected by the choice of power setting (1.0 vs 1.5 J per pulse), with total laser energy held constant.

A canine iliac artery occlusion model

This report describes an occlusive canine iliac artery model for use in experimental angioplasty procedures. Lesions were induced by overdistending and breaking the internal elastic lamina of the artery and implanting a 2-cm long occlusive collagen plug. The collagen plug diameter was varied to fit the iliac artery and caused immediate bilateral iliac occlusions. Histology of the lesions at 9 and 14 days (n = 2) showed that the lumen was filled with a mixture of fresh thrombus and collagen pad material (more collagen than thrombus) with focal disruptions of the internal elastic lamina. At 36 days (n = 2) the lumen was obliterated with a mixture of organizing thrombus and collagen pad material (more organizing thrombus than collagen). At 60 (n = 4) and 80 (n = 8) days the collagen pad had been completely replaced with organizing thrombus consisting of collagen fibers and hemosiderin-laden macrophages with persistent focal disruptions of the internal elastic lamina. These initial data demonstrate the ability to create fibrotic arterial occlusions in as short a time as 60 days and to provide a practical model to study methods for treating localized peripheral vascular occlusive disease.

Holmium:YAG laser ablation of human intervertebral disc: preliminary evaluation

Percutaneous discetomy has become a viable alternative in the treatment of herniated intervertebral disc. This study determined the effectiveness of holmium: YAG laser for ablation of human disc tissue. Human cadaveric intervertebral disc was harvested and stored in cold saline-soaked gauze for evaluation within 24 hr of removal. Using a specially designed apparatus, a 600 microns diameter fiber was advanced perpendicular through the annulus fibrosis at a controlled force of 0.098 Newtons (10 g). Samples were lased in air (n = 17) and in room temperature saline (n = 32). The laser energy was delivered at 5 Hz, 250 microseconds pulsewidth, and from 50 mJ/mm2 to 1,100 mJ/mm2 fluence. Three to six holes were lased using identical parameters in each tissue specimen and were evaluated histologically and by morphometric analysis. The maximum zone of thermal necrosis and thermal denaturation occurred at 700-1,100 mJ/mm2; 140 microns and 590 microns in air and 80 microns and 730 microns in saline, respectively. At fluences between 200 and 700 mJ/mm2, the thermal necrosis ranged from 20 to 60 microns in air and from 10 to 50 microns in saline, the zone of denaturation also being less. The holes created with the 600 microns fiber were circular in shape, with a mean diameter of 500 microns (n = 3). The etch rates (penetration/pulse) appeared to increase with increasing fluences. In saline, the etch rate ranged from 7 to 53 microns/pulse (r = 0.57, P less than or equal to 0.10), and, in air, the values ranged from 7 to 65 microns/pulse (r = 0.79, P less than or equal to 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Stenosis following laser thermal angioplasty--a blinded controlled randomized study between aspirin against Probucol

Long-term patency of vascular angioplasties is limited by stenosis from neointimal hyperplasia or progressive arteriosclerosis. This study evaluated the hypothesis that ASA (an antiprostaglandin) or Probucol (an antioxidant) may be useful in preventing stenosis following laser thermal angioplasty. Aortoiliac arteriosclerosis was induced in 17 female New Zealand white rabbits with a combination of endothelial denudation (4 Fr. Fogarty balloon catheters) and 2% cholesterol-supplemented diet for 6 weeks. All rabbits then underwent arteriography and were immediately randomized to one of three groups: Group I (n = 6), control, laser but no adjunctive therapy; Group II (n = 5), laser and ASA 10 mg/kg/day; Group III (n = 6), laser and 1% Probucol diet. Retrograde laser thermal angioplasty was performed with a 1-mm coronary Laserprobe. Six watts of argon laser energy was delivered for a single 5-sec pulse using a continuous motion from the right common iliac artery to the aorta. Pre- and postlaser arteriography was performed in all groups. Rabbits were sacrificed 1 month following laser angioplasty, and aortoiliac sections were taken after in situ perfusion fixation with paraformaldehyde and 0.05% glutaraldehyde. Serial 5-mm segments, proximal to the aortic bifurcation and distally from the same, were taken, stained, and evaluated by quantitative morphometry. From each segment, lesion area and lesion area/internal elastic laminae area were evaluated and compared. Serum cholesterol increased from 60.8 +/- 19.5 to 1494.7 +/- 12.7 mg% following institution of the cholesterol diet (P less than 0.05). Arteriosclerotic lesions were observed in all rabbits and maximally located around the common iliac artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotoxicity and atherogenicity of cholesterol oxides

Cholesterol in the diet can readily autoxidize and be absorbed and transported in plasma lipoproteins. Cholesterol oxides can also be endogenously produced in tissues via free-radical-induced reactions. Some cholesterol oxides, notably cholestane-3 beta, 5 alpha, 6 beta-triol and 25-hydroxycholesterol, have been shown to cause injury to vascular endothelial and smooth muscle cells, to alter LDL receptor function, to enhance cholesteryl ester accumulation, to inhibit prostacyclin production, and to induce experimental atherosclerosis alone or in combination with cholesterol. An epidemiological study examining relationships between atherosclerosis and plasma levels of cholesterol oxides as independent risk factors may provide additional insights regarding the roles of cholesterol oxides in atherogenesis.

In vivo study of an elastomer end-coated polytetrafluoroethylene vascular prosthesis

Polyurethane end-coated polytetrafluoroethylene (PTFE) grafts (elastomer PTFE grafts) were implanted in 12 female adult mongrel dogs to assess patency, intimalization, tissue incorporation, and technical suitability of the material as a vascular graft. Each dog had bilateral aortoiliac grafts placed, one a standard PTFE and the other an elastomer PTFE graft. The length of the grafts was 7-8 cm and the diameter was 6 mm. The grafts were harvested at intervals to 120 days postoperatively. The elastomer PTFE grafts showed superior longitudinal elasticity, retention of shape, and no graft tearing with suture tension; however, no significant difference in bleeding was noted at the anastomoses between the standard and elastomer PTFE grafts. Satisfactory patency was obtained with both standard (8/10) and elastomer PTFE grafts (9/10) at 90-120 days. No significant difference in the thickness of intima and the length of pannus ingrowth was noted between the standard and elastomer PTFE grafts. No outer tissue incorporation was seen at the elastomer-treated graft segments as opposed to the well-incorporated untreated segments. In conclusion, elastomer end-coating of a PTFE vascular prosthesis provided excellent handling characteristics without detracting from patency; however, the lack of outer tissue incorporation may be a potential disadvantage in its clinical use.

Cholesterol oxides and carcinogenesis

Experimental evidence indicates a relationship between cholesterol alpha-epoxide and skin cancer, and exposure of skin fibroblasts to ultraviolet radiation enduces formation of significant levels of this oxide. Colon cancer is also etiologically linked to cholesterol oxidation products. Higher than normal levels of cholestanetriol have been found in patients with colon cancer and also in those with precancerous disorders such as adenomatous polyps and ulcerative colitis. Higher than normal levels of cholesterol alpha-epoxide have been found in breast fluid aspirates of women with benign breast disease, with or without atypical hyperplasia of the epithelium, and this may be a factor in the increased incidence of breast cancer associated with hyperplasia. Similarly, the observed increased levels of cholesterol alpha and beta-epoxides in prostatic fluid of men with benign prostatic hypertrophy may be associated with subsequent development of prostate cancer. Cholesterol alpha-epoxide has been found to be mutagenic to fibroblasts in culture and to induce morphological transformation in hamster embryo cells and in mouse C3H cells. 25-Hydroxycholesterol and 20 alpha-hydroxycholesterol are potent suppressors of generation and proliferation of tumor-specific cytotoxic T lymphocytes. Although investigations into the role of cholesterol oxidation products in cancer are still in the early stages, evidence to date indicates a potentially significant role in the induction of some types of cancer.

Experimental and early clinical evaluation of vascular anastomoses with argon laser fusion and the use of absorbable guy sutures: a preliminary report

This study investigated the feasibility of forming vascular anastomoses by use of argon laser tissue fusion and absorbable, monofilament polydimethylsiloxane guy sutures. In initial animal studies femoral arteriovenous fistulas approximately 1.5 cm in length were created bilaterally in each of 10 dogs and were studied histologically at 2, 4, 8, 16, and 24 weeks (two animals in each interval). In each animal, one anastomosis (control) was formed with continuous 6-0 polypropylene suture, and the contralateral anastomosis (experimental) was performed with an argon laser (0.5 watt, 5 to 7 minutes exposure, energy fluence 1100 to 1500 joules/cm2 per 1 cm length) with stay sutures of 5-0 polydimethylsiloxane at 0.5 to 0.65 cm intervals. At removal, all anastomoses were patent without hematomas, aneurysms, or luminal narrowing. Histologic examination at 2 to 16 weeks demonstrated resorption of the biodegradable suture material by a local inflammatory reaction. By 24 weeks, laser-fused specimens had no evidence of suture material at the anastomotic line, and healing consisted of a bond between artery and vein wall tissues. Control suture specimens at the same intervals exhibited an organized fibrous tissue response to the suture. Clinical adaptability of this technology has subsequently been evaluated in five patients at 10 to 27 months (21.6 +/- 5.8) by physical examination and duplex scanning and demonstrate no evidence of abnormal healing. This study establishes the experimental and preliminary clinical feasibility of laser-fused anastomoses aligned by biodegradable guy sutures and supports further investigation and refinement of the technique.

Holmium:YAG laser ablation of vascular tissue

The ablation of atherosclerotic lesions without collateral thermal or shock wave damage is thought to be a key element for successful laser angioplasty. This study evaluated the effectiveness of pulsed holmium:YAG laser (2.1 microns wavelength) for this application. Fresh normal tissue (n = 139) and arteriosclerotic canine arteries (n = 21) as well as formalin-preserved normal canine (n = 31) and atherosclerotic human arteries (n = 177) were irradiated under saline via a 600 microns diameter fiber placed perpendicular to the intimal surface with 0-10 gm of force. The laser was operated in the free running mode (FRM; 250 microseconds pulsewidth, 5 Hz, 30-7,100 mJ/mm2) and in the Q-switched mode (QSM; 200 nsec pulsewidth, 6 Hz, 30-1,100 mJ/mm2). Following the experiments, the samples were prepared for histologic and morphometric analysis. Ablation thresholds in the FRM were 60 and 180 mJ/mm2 in fresh and preserved canine tissue, respectively. Ablation thresholds in the QSM for fresh and preserved canine tissues were 75 and 180 mJ/mm2, respectively. Thresholds for human atherosclerotic tissue were dependent on the amount of calcification. In the QSM and FRM, there were no samples that could not be penetrated at 1,100 mJ/mm2 and above. Histologic examination of the FRM samples revealed confined columns of tissue ablation, with approximately 55-250 microns and 70-140 microns zones of thermal effect being apparent in the fresh and formalin-preserved samples, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of internal elastic laminae damage in the development of canine arteriosclerosis

This study was designed to test the hypothesis that the extent of damage to the internal elastic lamina (IEL) may be a factor in determining the development of atheromatous lesions (lesion area). A bilateral iliac artery arteriosclerotic (AS) model in seven dogs prepared by intimal denudation and fracture of the IEL plus 5% cholesterol diet was investigated. The animals were sacrificed at 10-52 weeks (10, n = 1; 16, n = 3; 20, n = 1; 32, n = 1; 52, n = 1). Histologic analysis of sections (n = 42) of 14 canine iliac AS arteries harvested bilaterally from identical locations along the vessels (2, 7, and 12 cm from the aortic bifurcation) were compared with control segments of caudal and femoral arteries (n = 12) that had intact lamina and no luminal trauma. AS segments at all sites along the length of the traumatized iliac vessels demonstrated significant lesions, while control vessels had no arteriosclerotic changes. AS lesion area was calculated using ocular micrometry and a multiple regression model to test the predictability of the lesion area from the following independent variables: (1) proportion of intact IEL to total IEL (IEL/IELt), (2) sacrifice intervalens (3) frequency of disruptions to the IEL, (4) side and level of the arterial lesion, and (5) respective animals. This analysis revealed that none of the coefficients for the independent variables used in the multiple regression model was significant, suggesting that the extent of AS lesions is not related to the size, frequency, or location of breaks in the IEL, although a break in IEL is required to initiate the lesions. This observation suggests that the migration of cells from the arterial media through the broken laminae or the release of medial biochemical mediators which are normally contained by the elastic lamina is required to develop the AS lesions in this canine model, and that any size break in the lamina initiates the process.

Direct cocaine cardiotoxicity demonstrated by endomyocardial biopsy

The morbidity and mortality associated with cocaine abuse has markedly increased in recent years. Although several articles indicate a possible connection of cocaine with coronary spasm and acute myocardial infarction, this study in seven patients with a history of cocaine abuse, who underwent endomyocardial biopsy, suggests that cocaine may cause direct toxicity to the myocardium. Myocardial specimens from five of seven patients showed multifocal myocyte necrosis, of which two specimens revealed focal myocarditis, while three specimens had changes consistent with dilated cardiomyopathy. Ultrastructurally, extensive loss of myofibrils and sarcoplasmic vacuolization were observed. It is postulated that the pathogenesis of acute cocaine-induced toxicity is direct destruction of myofibrils resulting in myocyte necrosis and that these changes may or may not be associated with interstitial inflammatory cell infiltrates. Long-term abuse of cocaine may lead to interstitial fibrosis and eventually congestive heart failure.

Relative specificities of inhibition of acid cholesteryl ester hydrolase and neutral cholesteryl ester hydrolase in cultured rabbit aortic smooth muscle cells by esterastin and cholesteryl oleyl ether

Rabbit aortic smooth muscle cells in culture were incubated with 0.04-500 M esterastin. Acid cholesteryl ester hydrolase (ACEH) and neutral cholesteryl ester hydrolase (NCEH) activities were inhibited to a comparable degree, with 50% inhibition occurring in the range of 0.4 M esterastin. Cells incubated with cholesteryl oleyl ether showed 50% inhibition of NCEH at 5.0 M, but no inhibition of ACEH over a concentration range of 0.2-20 M. This relative specificity of cholesteryl oleyl ether for NCEH can be employed to study the relative roles of ACEH vs. NCEH in preventing cellular cholesteryl ester accumulation.

The role of cholesterol oxidation products in the pathogenesis of atherosclerosis

Cholesterol undergoes spontaneous autoxidation, leading to the production of potentially atherogenic oxidation derivatives. When 25-hydroxycholesterol (25-OH) or cholestane-3 beta, 5 alpha, 6 beta-triol (triol) was injected intravenously into rabbits, the aortic surfaces showed numerous balloon-like protrusions and crater-like defects indicative of endothelial damage. Alterations in membrane function caused by these cholesterol oxides could be the mechanism for their cytotoxic effect. Carrier-mediated hexose transport by cultured rabbit aortic smooth muscle cells, measured using 2-deoxyglucose, was reversibly inhibited by triol within one hour. A membrane-bound enzyme, 5'-nucleotidase, was inhibited after 24 to 48 hrs incubation with either 25-OH or triol. Endocytosis was also significantly inhibited by both 25-OH and triol. Depletion of membrane cholesterol content by the cholesterol oxides could account for the membrane functional alterations. Cholesterol biosynthesis is markedly inhibited by 25-OH. Triol has a lesser effect on cholesterol biosynthesis, but it is more potent in blocking uptake of cholesterol by arterial cells in culture. Cholesterol oxides may also influence cholesteryl ester accumulation by arterial smooth muscle cells. Incubation of cells with 25-OH resulted in a four-fold increase in cholesterol esterifying activity but no effect on cholesteryl ester hydrolytic activity. The cholesterol oxides appear to be transported in the blood primarily by very low density lipoproteins (VLDL) and low density lipoproteins (LDL). Oxidized LDL has cytotoxic effects and enhances macrophage lipid accumulation. These be effects may be directly related to the cholesterol oxide content of these lipoproteins.

Initial human evaluation of argon laser-assisted vascular anastomoses

Forearm Brescia-Cimino arteriovenous fistulas were chosen for the initial clinical evaluation of argon laser-assisted anastomosis of human vessels. Ten patients with chronic renal failure had side-to-side radial artery/cephalic vein fistulas fused by laser. Incisions 1.2 to 1.5 cm in length were made in adjacent segments of artery and vein and were aligned for application of laser energy by four 6-0 polypropylene sutures. The sutures divided each fistula into four segments that were 5.0 to 6.5 mm long. Each segment was sealed satisfactorily in 75 to 100 seconds by use of 0.5 W, 1130 to 1520 joule/cm2 argon laser energy fluence. Seven (17.5%) of 40 bonds required an additional 7-0 biodegradable suture to close small gaps that did not fuse adequately. Serial prospective follow-up studies of the patients by physical examination and duplex scanning for periods of 12 to 20 months (15.4 +/- 2.8, n = 7) postoperatively have shown uniformly patent, compliant anastomoses with no evidence of hematomas, false aneurysms, or luminal narrowing. Histologic examination of two patent fistulas that were excised during revision procedures at 4 and 5 months postoperatively showed healing of the entire circumference of the anastomosis similar to that noted in extensive preclinical canine studies. We conclude from these preliminary results that argon laser vascular tissue fusion is possible in humans when reliable primary sealing of vascular anastomoses is achieved, and that healing occurs without aneurysmal dilatation during follow-up of up to 20 months.

Effects of cholesterol oxidation derivatives on cholesterol esterifying and cholesteryl ester hydrolytic enzyme activity of cultured rabbit aortic smooth muscle cells

The effects of 5 micrograms/ml of 25-hydroxycholesterol; cholestane-3 beta,5 alpha,6 beta-triol; and cholesterol on acyl CoA cholesterol acyltransferase, acid cholesteryl ester hydrolase and neutral cholesteryl ester hydrolase was studied in cultured rabbit aortic smooth muscle cells. After 1 hour incubation, 25-hydroxycholesterol resulted in a fourfold stimulation of acyl CoA cholesterol acyltransferase activity. No stimulation by 25-hydroxycholesterol was noted before 15 minutes or after 5 hours of incubation. Neither cholestane-3 beta,5 alpha,6 beta-triol nor cholesterol influenced acyl CoA cholesterol acyltransferase activity at any time interval. No significant effects of any of the sterols were noted on acid cholesteryl ester hydrolase or neutral cholesteryl ester hydrolase activity. The imbalance between acyl CoA cholesterol acyl transferase and hydrolase activities induced by 25-hydroxycholesterol could result in cholesteryl ester accumulation by arterial smooth muscle cells, which may be associated with atherosclerosis.

Light chain cardiomyopathy associated with small-vessel disease

Intramyocardial small-vessel disease associated with systemic light chain deposition is a rare condition that may occur in patients with monoclonal plasma cell proliferation. This article describes a 39-year-old woman who had experienced several episodes of subendocardial myocardial infarction and was found to have plasma cell dyscrasia. Endomyocardial biopsy revealed kappa light chain deposits along the sarcolemmal and vascular basement membranes, the latter of which resulted in vascular occlusion and myocardial infarction. Postmortem examination showed polyvisceral deposition of kappa light chains. This rare complication of plasma cell proliferative process has a poor prognosis.

Canine peripheral vascular arteriosclerosis following myointimal fragmentation and atherogenic diet

The development of arteriosclerotic peripheral vascular lesions following balloon catheter and mechanical fragmentation of the arterial myointima combined with an atherogenic diet was studied in a canine model. The ileofemoral arteries of five mongrel dogs (mean wt 22 +/- 2 kg) were selectively cannulated and subjected to balloon catheter and mechanical myointimal injury by repeated longitudinal and transverse shearing forces. Twenty grams of hydrogenated coconut oil and a 5.0% cholesterol diet were fed to the animals daily during the study period. Followup angiographic studies obtained at 4 weeks (n = 2), 10 weeks (n = 3), 16 weeks (n = 3), and 24 weeks (n = 2) demonstrated changes of progressive peripheral vascular occlusion. Concurrent duplex Doppler studies correlated well with the angiographic results. At 10 (n = 1), 18 (n = 2), and 24 (n = 2) weeks, the animals were sacrificed and the vessels were perfusion-fixed in situ with 2% glutaraldehyde or formaldehyde solutions and excised. Histological examination demonstrated extensive arteriosclerotic changes including (i) fragmentation and reduplication of the internal elastic membrane, (ii) myointimal hyperplasia with fibroblastic proliferation including the development of fibrous intimal plaques, and (iii) transmigration and proliferation of smooth muscle cells with scattered monohistiocytes. The specimens showed a range of stenotic changes from 25% to total occlusion of the vascular lumen. These preliminary data demonstrate the feasibility of providing intense arteriosclerotic myointimal histologic changes in the canine peripheral vasculature within a 24-week period. Further refinement of this methodology may provide a practical model for studies of localized peripheral vascular occlusive disease.

Mechanism of tissue fusion in argon laser-welded vein-artery anastomoses

The mechanism of laser vascular tissue welding remains unknown. This study compared the acute tissue response and long-term healing of sutured and laser-welded anastomoses of vein segments used to bypass ligated canine femoral arteries. For each procedure, one anastomosis was formed using running 6-0 polypropylene suture (control), and the other anastomosis was formed using argon laser tissue welding (experimental). The vein grafts were harvested at 4 (n = 2), 8 (n = 1), 12 (n = 1), and 16 (n = 2) weeks, and selected samples were evaluated by histologic examination, electron microscopy, tensile strength testing, and by measuring the formation of [3H]hydroxyproline as an index of collagen synthesis. Examination of successful laser fusions immediately after they were formed showed bonding of collagen to collagen and elastin to collagen. Follow-up evaluations showed that the precision of tissue apposition affected the rate of healing and tensile strength. Laser-welded anastomoses demonstrated a progression of healing similar to sutured repairs, with remodeling of fibrous tissue and collagen being the primary component of weld integrity. This study demonstrates that sutured and argon laser-welded vein-artery anastomoses heal comparably up to 16 weeks postoperatively, and that laser welding is a satisfactory alternative to sutured anastomoses.

Aortitis presenting as Buerger's disease

Buerger's disease is frequently diagnosed in young smokers, based on clinical presentation rather than histologic criteria. This report describes a young male with idiopathic aortitis who had been managed for 10 years as Buerger's disease solely on the basis of clinical manifestations. This case emphasizes the need for establishing histopathologic, and perhaps biochemical, criteria to identify the underlying arteriopathy.

Laser vascular welding--how does it work?

This study evaluated the histology and electron microscopy of four samples of 2 cm long venotomies and artery-vein anastomoses formed in canine femoral arteries and veins using the argon laser (0.5 W power, 1 800 J/cm2, 4 min exposure/1 cm length of anastomosis). Welds were continuously irrigated with saline during the procedure to limit maximal temperatures to 44.2 +/- 1.6 degrees C (mean +/- SD), and the specimens were removed immediately following fusion and preserved for examination. Histologic and electron microscopic examination of different areas of the welds revealed various mechanisms of fusion including a) apposition of denatured collagen and elastin in the media and adventitia; b) bonding of vein medial collagen and elastin to the internal elastic membrane of the artery; and c) fusion consisting of a coagulum of platelets and fibrin depending on the alignment and apposition of the vessel edges. This study demonstrates that vascular tissue fusion by the argon laser occurs by various mechanisms. Future experiments should delineate which types of seal produce the optimal strength at the time of fusion, and enhance long-term healing.