Heavy fermions. Unconventional Fermi surface in an insulating state.

Insulators occur in more than one guise; a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here, we report the observation of an unusual insulating state with an electrically insulating bulk that simultaneously yields bulk quantum oscillations with characteristics of an unconventional Fermi liquid. We present quantum oscillation measurements of magnetic torque in high-purity single crystals of the Kondo insulator SmB6, which reveal quantum oscillation frequencies characteristic of a large three-dimensional conduction electron Fermi surface similar to the metallic rare earth hexaborides such as PrB6 and LaB6. The quantum oscillation amplitude strongly increases at low temperatures, appearing strikingly at variance with conventional metallic behavior.

Orbital solitary fibrous tumor: radiographic and histopathologic correlations.

OBJECTIVE: To correlate the clinicopathologic and radiographic features characteristic of orbital solitary fibrous tumor (SFT). METHODS: The diagnostic features and clinical outcome of seven adults with orbital SFT are retrospectively outlined. Orbital imaging was performed by ultrasonography, computed tomography, or magnetic resonance imaging. Some cases were imaged by multiple modalities. Histopathologic examination of each tumor specimen included standard light and immunohistochemical stains. RESULTS: Heterogeneous internal composition was better appreciated on magnetic resonance imaging than on computed tomography. All cases undergoing magnetic resonance imaging showed T1 isointensity and T2 hypointensity relative to gray matter. Strong, generalized immunohistochemical reactivity to vimentin and CD34 validated the diagnosis of SFT and differentiated the specimens from other spindle cell neoplasms. After complete tumor resection, our patients remain tumor free with postoperative intervals of 15 to 45 months. CONCLUSIONS: Solitary fibrous tumor has now been reported in 26 orbits. No physical finding is pathognomonic, but several imaging traits are highly characteristic. Intralesional image heterogeneity and a predominantly low T2 signal intensity are distinctive of SFT. Complete tumor resection and immunohistologic specimen evaluation are emphasized. Clinicians should consider the diagnosis of SFT when confronted with an adult patient having an orbital soft tissue mass demonstrating the distinctive magnetic resonance imaging findings.

Intracranial abscess as a complication of subperiosteal abscess of the orbit.

PURPOSE: To describe the potential complication of intracranial abscess in the setting of orbital abscess. METHODS: We retrospectively reviewed case reports and the literature. Three patients were found to have pansinusitis progressing to subperiosteal abscess of the orbit and subsequent intracranial abscess. RESULTS: Three patients, ages 14, 26, and 57 years, with concurrent pansinusitis, subperiosteal abscess of the orbit, and intracranial abscess were treated with intravenous antibiotics and surgical drainage of the orbital abscess and sinuses. Two of the three patients required drainage of the intracranial abscess. CONCLUSIONS: Although rare, intracranial abscess is a life-threatening complication of orbital abscess. It requires aggressive intervention by a multidisciplinary team.

Update on orbital floor fractures: indications and timing for repair.

There has been much discussion and controversy over the management of blowout fractures of the orbit. At various times, recommendations have included operating on all orbital floor fractures and operating on none of them. As our understanding of blowout fractures and their sequelae has evolved over time, so too has understanding of when and whom would benefit from surgery. In the past, the focus has often been on early versus late repair. The focus should really be on understanding the mechanisms of diplopia and enophthalmos in orbital floor fractures, the best way to evaluate a patient, and, finally, the best method of restoring maximal function and appearance. We present herein a historical perspective on the management of orbital floor fractures and our current recommendations for the indications and timing of surgical repair.

Cutaneous malignant melanoma metastatic to the eyelid.

Cutaneous malignant melanoma metastatic to the choroid, orbit, or vitreous is rare. Metastatic lesions to the eyelid are rare as well. The authors report a case of malignant melanoma metastatic to the eyelid. This was the first sign of tumor recurrence in a patient who was thought to have been successfully treated for a melanoma of the back 3 years previously. The patient died 6 weeks after diagnosis of the eyelid lesion. In the presence of known malignancy, metastasis must be suspected in new eyelid lesions.

Paranasal sinus endoscopy and orbital fracture repair.

Although excellent results may be achieved in the management of many orbital floor injuries with standard transconjunctival or transcutaneous approaches, visualization of the posterior edge of the orbital floor or medial wall defect may be challenging at times. We describe our experience using endoscopic examination of the orbital floor through maxillary sinus approaches during the repair of selected orbital floor fractures. Owing to the posterosuperior angulation of the orbital floor, these approaches allow better visualization of the posterior edge of fractures involving the posterior portion of the orbital floor than do the standard transconjunctival approaches, and they facilitate confirmation that all orbital soft tissues have been elevated from the fracture site. We have used these techniques successfully in 9 patients with fractures involving either the posterior portion of the orbital floor or the medial wall or both.

The multidisciplinary management of psammomatoid ossifying fibroma of the orbit.

OBJECTIVE: To discuss the multidisciplinary management of psammomatoid ossifying fibroma (POF) of the orbit and to clarify the clinicopathologic terminology. DESIGN: The authors present a cohort of cases of POF involving the frontal and ethmoid sinuses and the orbit and discuss the nomenclature and literature. PARTICIPANTS: Three patients with POF and their treatment are discussed. INTERVENTION: Patients were worked up and treated by a multidisciplinary team using imaging studies and histopathologic analysis. Reconstruction, if necessary, was carried out at the time of excision or in a second-stage procedure. MAIN OUTCOME MEASURES: In each case, the lesion was completely excised and has not recurred. RESULTS: The diagnosis of POF was made in each case, and the patient underwent successful resection of the tumor. CONCLUSION: The authors' experience suggests that a multidisciplinary approach, including a radiologist, pathologist, neurosurgeon, otolaryngologist, craniofacial surgeon, and orbital specialist, may be useful in the evaluation and management of these lesions.

The role of the integrin family of adhesion molecules in the development of tumors metastatic to the orbit.

Tumors metastatic to the orbit frequently originate from certain primary tumors such as breast, lung, prostate, and melanoma. The site-specific nature of orbital metastases, as well as that of other metastatic lesions, cannot be the result of random seeding. We present evidence from a review of the literature demonstrating that tumor cells express adhesion molecules of the integrin family, and that these receptors play a pivotal role in the development of a metastatic colony. We investigated orbital metastatic lesions from prostate carcinoma, malignant melanoma, and lobular breast carcinoma to determine the level of integrin expression by immunohistochemistry. Several integrin subunits (alpha2, alpha4, beta3) were found to have increased expression in the metastasis when compared to normal prostate tissue and normal melanocytes. The increased expression of these integrins may be responsible for the tendency of these tumors to metastasize to the orbit, as well as for the tendency of prostate tumors to metastasize to bone. The results from the staining of the breast metastasis were inconclusive.

Adjustable suture technique for levator recession.

OBJECTIVE: To determine whether an adjustable suture technique is clinically useful in levator recession surgery. DESIGN: Consecutive clinical series. SETTING: Inpatient hospital and ambulatory surgical center. PARTICIPANTS: Ten patients who were undergoing levator recession surgical procedures for correction of eyelid retraction constituted the group of subjects of this study. OUTCOME MEASURES: Outcome measures included margin-reflex distance and palpebral fissure measurements. RESULTS: Postoperative margin-reflex distance and palpebral fissure measurements were within 0.5 mm of the desired eyelid position in 10 or 14 procedures and within 1 mm of the desired position in 12 of 14 procedures. CONCLUSION: Adjustable sutures may be a useful adjunct in levator recession surgery.

Ocular toxicity following topical application of anesthetic cream to the eyelid skin.

BACKGROUND AND OBJECTIVE: The use of topical anesthetic cream in the periorbital region may be of clinical value. The potential for toxic effects from such use has not been studied in a controlled manner. This study was performed to evaluate the potential ocular toxicity of anesthetic cream topically applied to the eyelid in an animal model. MATERIALS AND METHODS: Ten rabbits underwent periorbital eutectic mixture of local anesthetics (EMLA) (2.5 percent lidocaine and 2.5 percent prilocaine) application and were observed for evidence of gross or microscopic ocular toxicity. Baseline external and anterior segment examinations were performed, including biomicroscopy and fluorescein staining, after which a standard quantity of EMLA cream (0.75 g) was applied along the upper eyelid and covered with an occlusive dressing. After 1 hour of treatment, the eyelid and anterior segment were examined for evidence of adverse reaction. The eyelids were excised and examined histopathologically. RESULTS: No significant adverse effects were noted on external lid and anterior segment examination. The histopathologic findings were within normal limits. CONCLUSIONS: This study suggests that external application of EMLA cream to the eyelid does not induce local toxicity in the rabbit model. The external application of EMLA cream may be safe in the periorbital region.

Outcome of isolated coronary artery bypass surgery in octogenarians.

BACKGROUND: Between 1989 and 1992 100 consecutive patients aged 80 or older underwent isolated coronary artery bypass grafting (CABG) in our institution. Eighty-six percent had angina grade III or IV symptoms. METHODS: Emergency surgery was required in 31, urgent surgery in 30, and elective surgery in 39 patients. The average left ventricular ejection fractions (LVEF) in these groups were 36%, 43%, and 45% respectively. The operative mortality was 8% for these octogenarians compared to 2% in the younger cohort (p = 0.002). It was zero in elective cases and 13% (8/61) in urgent and emergency cases. It was increased by preoperative admission to coronary care unit (CCU) (p = 0.02), urgency of operation (p = 0.02), the use of intra-aortic balloon pump (IABP) (p = 0.0002), preoperative renal dysfunction (p < 0.03), and < or = 3 grafts (p < 0.04). The late mortality was increased by LVEF < or = 20% (p = 0.03) and operation from CCU (p < 0.05). On multivariate stepwise logistic regression analysis, the use of IABP (p < 0.0003) and preoperative renal dysfunction (p < 0.02) were independent predictors of operative mortality. LVEF < or = 20% was the only independent predictor (p < 0.02) of late mortality. RESULTS: Actuarial survival was noted to be 87%, 80%, 77%, and 73%, respectively, at 1, 2, 3, and 4 years, with two cardiac-related late deaths. Long-term follow-up revealed that 97% of patients had no or minimal anginal symptoms. CONCLUSIONS: Due to increasing use of nonsurgical options, the profile of elderly referred for CABG currently involves gravely ill patients with comorbidities. CABG under elective conditions, before deterioration of left ventricular function, can achieve normal life expectancy and good symptomatic relief in octogenarians.

Tuberculosis of the breast as a presenting manifestation of AIDS.

Tuberculous infections of the breast are considered rare in the developed world. We describe a case of mammary tuberculosis in a woman who was not initially known to be seropositive for the human immunodeficiency virus (HIV) and who was thought to have a pyogenic breast abscess. This uncommon presentation of extrapulmonary tuberculosis as an AIDS-defining condition highlights the necessity for performing mycobacterial smears and cultures in such cases when patients are at risk for HIV infection.

Structural analysis of the mouse mdr1a (P-glycoprotein) promoter reveals the basis for differential transcript heterogeneity in multidrug-resistant J774.2 cells.

In multidrug-resistant mouse J774.2 cells, the differential overproduction of functionally distinct phosphoglycoprotein isoforms reflects the amplification or transcriptional activation or both of two mdr gene family members, mdr1a and mdr1b. The mdr1a gene is a complex transcriptional unit whose expression is associated with multiple transcript sizes. Independently selected multidrug-resistant J774.2 cell lines differentially overexpress either 4.6- and 5.0-kilobase (kb) or 4.7- and 5.1-kb mdr1a transcripts. However, abundant overproduction of the mdr1a gene product was observed only in cell lines which overexpressed the 4.6- and 5.0-kb mRNAs. In order to determine the basis for mdr1a transcript heterogeneity and the relationship between transcript size and steady-state mdr1a protein levels, genomic and cDNA sequence analyses of the 5' and 3' ends of the mdr1a gene were carried out. Promoter sequence analysis and primer extension mapping indicated that mdr1a transcripts were differentially initiated from two putative promoters to generate either 5.1- and 4.7-kb or 5.0- and 4.6-kb transcripts in four multidrug-resistant J774.2 cell lines. Sequence analysis of 3' cDNA variants and a 3' genomic fragment revealed that the 5.1- and 5.0-kb mRNAs had identical 3'-untranslated regions which differed from those of the 4.7- and 4.6-kb mRNAs as a result of the utilization of a more downstream alternative poly(A) addition signal. Transcript initiation from the putative upstream promoter correlated with a 70 to 85% decrease in steady-state mdr1a protein levels relative to transcript levels. In addition, the identification of putative AP-1 and AP-2 promoter elements suggests a possible role for protein kinase A and protein kinase C in the regulation of mdr1a. The implications of these findings for mdr gene expression and regulation are discussed.

Björk-Shiley valve malfunction by prolapsed sutures.

Severe aortic regurgitation developed in three patients after aortic valve replacement within six months due to long sutures prolapsing across the "annulus" of Björk-Shiley prosthesis. At reoperation the offending sutures were trimmed or tucked back to the aortic wall to eliminate aortic regurgitation. Prolapse of unravelled knots may be the likely cause. Everting the sewing skirt during the first replacement may prevent this complication.

Survival after coronary surgery.

A 4.4 year follow-up study has been done on a previously reported group of 200 consecutive patients who underwnet coronary bypass. The yearly mortality rate has been 1% (8/200 in 4 years). Our total group of 1,038 surgically treated patients has had an operative mortality rate of 1.3%, and an early graft patency rate of 89.6% has been recorded in the 60% of patients consenting to restudy. These results are compared to natural history studies with and without angiography. Comparison with recent prospective randomized studies of patients with chronic stable angina and those with unstable angina suggests that a low operative mortality rate and optimal technical performance are necessary to improve the survival rate of patiens with symptomatic obstructive coronary disease.

Comparative study of the postoperative flow in the saphenous vein and internal mammary artery bypass grafts.

Postoperative coronary bypass flow was evaluated in two groups of randomly selected patients with grafts to the left anterior descending artery (LAD). Saphenous vein bypass grafts were placed in 27 patients and internal mammary artery grafts in 25 patients. Postoperative flow studies were performed in both groups with roentgendensitometric methods based on the transit time of radiopaque media along the graft plus the mean graft diameter. There was no significant difference between the two groups of patients for age, duration of symptoms, or the frequency of hypertension, diabetes mellitus, prior myocardial infarction, or cardiomegaly. Intraoperative bypass flows were 75+/-27 and 77+/-24 ml. per minute for the saphenous vein group (SVG) and internal mammary artery group (IMAG), respectively. There was no significant difference in the heart rate or mean aortic pressure at the time of the roentgendensitometric flow study. The mean graft diameters were 3.0+/-0.5 and 1.9+/-0.3 mm. for the SVG and IMAG, respectively (p less than 0.001). The ratios of graft diameter to LAD diameter were 1.9+/-0.3 and 1.2+/-0.2 for the SVG and IMAG, respectively (p less than 0.001). The roentgendensitometric postoperative flows were 68+/-27 ml. per minute in the SVG and 46+/-16 ml. per minute in the IMAG (p less than 0.01). The present study indicates that flow in significantly higher in saphenous vein than in internal mammary artery bypasses and that the difference in flow may in part be explained on the basis of the graft diameter.

Effects of contrast medium on left ventricular pressure and volume with emphasis on coronary artery disease.

Forty-one patients had left ventricular angiography repeated 3 minutes after an initial study in order to evaluate the effect of angiographic contrast medium on left ventricular end-diastolic pressure (EDP) and volume (EDV). Seven patients had no evidence of heart disease (normal group) and 34 patients had coronary artery disease. Single-vessel diseae was present in 10, double-vessel disease in 10, and triple-vessel disease in 14 patients. Seven other patients with radiopague epicardial clips previously attached to the left ventricle underwent cinefluorographic studies to determine end-diastolic intraclip distance at various intervals after a left ventricular angiogram. In all the groups studied there was a significant increase (p less than 0.005) in both the left ventricular EPD and EDV in the second angiographic study as compared to the first. This increase in EDV (deltaV) was similar in all groups. However, the increase in EDP (deltaP) was significantly greater (p less than 0.01) in patients with double- and triple-vessel disease as compared to the normal and single-vessel disease groups. Ejection fraction, per cent shortening of the heart axis, and contractile pattern in the normal subjects were not singnificantly different when the second angiographic study was compared to the first. In nine of 34 patients with coronary artery disease the second angiographic study demonstrated impairment in left ventricular contractile pattern not present in the first angiographic study. Cinefluorographic study demonstrated an increase in end-diastolic intraclip distance after the left ventricular angiogram. The change in intraclip distance corresponded directionally and temporally to the changes in left ventricular EDP. The present study revealed that the increase in left ventricular end-diastolic press-re associated with the injection of angiographic contrast medium can be explained by an increase in EDV and that such changes last for over 15 minutes and may be associated with alterations in the contractile pattern of the left ventricle.

Should the pericardium be closed after an open-heart operation?

A controlled clinical study was carried out to decide whether the pericardium should be left open or closed after open-heart operations. One hundred patients had the pericardium closed with interrupted silk, another 100 had the pericardium left open. Complications were alike except for the more frequent occurrence of a pericardial rub in the closed group (14 vs 3 patients), though the incidence of post-pericardiotomy syndrome was equal. There was no late tamponade. Two early reexplorations for bleeding were done in the open group, none in the closed. There were no postoperative deaths. In the patients who consented to postoperative angiography following revascularization procedures, the incidence of graft failure was equal in both groups. The pericardium should be closed after an open-heart operation. Morbidity and mortality are unchanged, and repeat cardiac exploration is safer.

Analogy tests and psychopathology at follow-up after open heart surgery.

A study of 100 coronary bypass and cardiac valvular surgery patients investigated whether preoperative brain damage, as measured by the Conceptual Level Analogy Test (CLAT), is a major risk factor for postoperative psychiatric symptoms and mortality. Three cognitive psychological tests, including the CLAT, and psychatric interviews were given preoperatively, postoperatively, and at 18-month follow-up. Surgical outcome was specified as: Catastrophic Outcome (death or severe stroke), Psychiatric Complications, or Good Outcome (survival with no psychiatric complications). Inhospital outcome related significantly to analogy test scores, as did both surgical procedure and diagnosis of rheumatic heart disease. However, long-term outcome was unrelated to medical diagnosis and only weakly related to surgical procedure, but highly significantly related to preoperative analogy scores. The CLAT was a more consistent predictor of both short- and long-term outcome than any of the other ten variables considered (medical and surgical variables, inhospital outcome, demographic measures, other psychological tests).