Radiofrequency heating pathways for gold nanoparticles.

This feature article reviews the thermal dissipation of nanoscopic gold under radiofrequency (RF) irradiation. It also presents previously unpublished data addressing obscure aspects of this phenomenon. While applications in biology motivated initial investigation of RF heating of gold nanoparticles, recent controversy concerning whether thermal effects can be attributed to nanoscopic gold highlight the need to understand the involved mechanism or mechanisms of heating. Both the nature of the particle and the nature of the RF field influence heating. Aspects of nanoparticle chemistry which may affect thermal dissipation include the hydrodynamic diameter of the particle, the oxidation state and related magnetism of the core, and the chemical nature of the ligand shell. Aspects of RF which may affect thermal dissipation include power, frequency and antenna designs that emphasize relative strength of magnetic or electric fields. These nanoparticle and RF properties are analysed in the context of three heating mechanisms proposed to explain gold nanoparticle heating in an RF field. This article also makes a critical analysis of the existing literature in the context of the nanoparticle preparations, RF structure, and suggested mechanisms in previously reported experiments.

Overexpression of petunia chalcone isomerase in tomato results in fruit containing increased levels of flavonols.

Tomatoes are an excellent source of the carotenoid lycopene, a compound that is thought to be protective against prostate cancer. They also contain small amounts of flavonoids in their peel ( approximately 5-10 mg/kg fresh weight), mainly naringenin chalcone and the flavonol rutin, a quercetin glycoside. Flavonols are very potent antioxidants, and an increasing body of epidemiological data suggests that high flavonoid intake is correlated with a decreased risk for cardiovascular disease. We have upregulated flavonol biosynthesis in the tomato in order to generate fruit with increased antioxidant capacity and a wider range of potential health benefit properties. This involved transformation of tomato with the Petunia chi-a gene encoding chalcone isomerase. Resulting transgenic tomato lines produced an increase of up to 78 fold in fruit peel flavonols, mainly due to an accumulation of rutin. No gross phenotypical differences were observed between high-flavonol transgenic and control lines. The phenotype segregated with the transgene and demonstrated a stable inheritance pattern over four subsequent generations tested thus far. Whole-fruit flavonol levels in the best of these lines are similar to those found in onions, a crop with naturally high levels of flavonol compounds. Processing of high-flavonol tomatoes demonstrated that 65% of flavonols present in the fresh fruit were retained in the processed paste, supporting their potential as raw materials for tomato-based functional food products.

Experience with a partnership program for cardiac surgery at a regional military medical center.

A Partnership Program between USAF Medical Center, Wright-Patterson (WPAFB) and Miami Valley Hospital (MVH), Dayton, Ohio, was created through CHAMPUS to provide cardiac surgical services for eligible patients. During the first year of this program, 82 patients underwent 89 percutaneous transluminal coronary angioplasty (PTCA) procedures. Sixty-one patients underwent cardiac surgery at WPAFB, 50 were referred to MVH due to ineligibility or other reasons, and five were referred to other military or civilian hospitals. The program has been successful with low morbidity and mortality (3%). Cost savings for PTCAs was $241,853 and for cardiac surgery was $462,046.

Characterization of Chinese hamster ovary cells that are resistant to 3-beta-[2-(diethylamino)ethoxy]androst-5-en-17-one inhibition of low density lipoprotein-derived cholesterol metabolism.

The pharmacological agent U18666A (3-beta-[2-(diethylamino)ethoxy]androst-5-en-17-one inhibits the intracellular transport of low density lipoprotein (LDL)-derived cholesterol in Chinese hamster ovary (CHO) cells. LDL-derived cholesterol accumulates in the lysosomes of U18666A-treated cells causing delayed LDL-mediated regulation of cellular cholesterol metabolism and impaired movement of LDL-derived cholesterol to other cell membranes. As a result of impaired LDL-derived cholesterol transport, LDL-dependent growth of CHO cells is also inhibited by U18666A. By selecting for cell growth in the presence of U18666A, we have identified a CHO cell line, designated U18R, that is resistant to U18666A-inhibition of LDL-derived cholesterol trafficking. When compared to parental CHO cells, U18R cells are relatively resistant to U18666A inhibition of LDL-derived cholesterol transport as well as LDL-mediated regulation of cellular cholesterol metabolism. In cell fusion experiments, the U18666A resistance observed in U18R cells displays a dominant phenotype. Identification of the U18666A-resistant factor may provide important insights toward the understanding of intracellular LDL-derived cholesterol regulation and trafficking.

Left main coronary artery aneurysm in association with severe atherosclerosis: a case report and review of the literature.

Aneurysms of the coronary arteries occur in from 0.3% to 4.9% of angiograms. Only 12 cases of left main artery (LMA) aneurysms have been reported. Of these, seven were associated with atherosclerosis in patients more than 56 years old. This report details the case of a 39-year-old patient with a large LMA aneurysm associated with atherosclerosis.

Long-term followup of penetrating abdominal aortic injuries after 15 years.

Eleven of 14 survivors who sustained trauma to the abdominal aorta have been evaluated 16 to 18 years after injury through personal interview, physical examination, and abdominal contrast computerized tomography (CCT). The average age of survivors was 39 years (range, 37-47). All patients had minimal debridement of the aortic injury with lateral arteriorrhaphy. No patients had symptoms of arterial insufficiency. However, five patients had abnormal ankle/brachial indices (ABI). In four patients, ABI was less than 1.00 at rest and a fifth patient's ABI decreased significantly: 0.60 left and 0.65 right from an average of 1.00 bilaterally after standardized exercise treadmill. CCT evaluation revealed aortic calcification in five patients in the area of aortic injury. Aortic calcification occurred only in the patients with abnormal ABI's. This long-term followup identifies no evidence for late compromise in the aorta; however, there is a suggestion that injury and repair may contribute to the accelerated development of atherosclerosis.

A comparison of patients with endoscopic esophageal perforations and patients with Boerhaave's syndrome.

A review was conducted to ascertain whether patients who suffered spontaneous postemetic esophageal rupture (Boerhaave's syndrome) experienced higher morbidity and mortality than patients who had endoscopic iatrogenic esophageal perforations. Review of the records of three medical centers from 1960 to 1985 identified 11 patients with Boerhaave's syndrome (group B) and 19 with iatrogenic perforations (group E). In group B, four patients were diagnosed greater than 24 h after perforation. Nine were treated surgically; of these one died. Two group B patients who were treated conservatively survived. In group E, only four patients were diagnosed greater than 24 h after perforation. Of 19 patients, 15 were treated surgically and four, medically. In group E, three patients died (one surgically and two conservatively treated). This study suggests that there is little difference in mortality between the two groups of patients as long as the diagnosis is made early and therapy is instituted promptly.

Supine cross-table lateral chest roentgenogram for the detection of pericardial effusion.

We performed a prospective, blinded, controlled study to test the hypothesis that supine cross-table lateral chest roentgenograms might have an advantage over conventional lateral chest roentgenograms for the detection of pericardial effusion using the epicardial fat stripe sign. In comparison with echocardiography as the gold standard, we found that supine cross-table lateral chest roentgenograms had greater sensitivity (51%) for pericardial effusions than conventional lateral chest roentgenograms (sensitivity, 31%). Specificity was essentially the same for both techniques. A large pericardial effusion was more readily detected by supine cross-table lateral chest roentgenograms (86%) than by the conventional lateral chest roentgenograms (36%). We conclude that a supine cross-table lateral chest roentgenogram should be included in the evaluation of patients with suspected pericardial effusion or in patients in whom a large cardiac silhouette is detected on a standard chest roentgenogram.

Intraoperative local anesthetic injection of the carotid sinus nerve. A prospective, randomized study.

One hundred patients undergoing carotid endarterectomy under general anesthesia were prospectively randomized to receive either a local anesthetic injection of their carotid sinus nerve with bupivacaine (Marcaine) or no injection. Systolic blood pressure and pulse rate were recorded before injection and at 5 and 30 minutes after injection. The need for intraoperative and postoperative use of systemic vasopressor and vasodilator medications was recorded for each group as was the incidence of arrhythmias, neurologic complications, and myocardial infarctions. Intraoperative local anesthetic injection of the carotid sinus nerve did not significantly influence the intraoperative pulse rate or incidence of hypotension. It did, however, significantly increase the incidence of intraoperative hypertension and the need for systemic vasodilator medications intraoperatively. The incidence of postoperative hypotension (6 percent of patients), hypertension (34 percent), arrhythmias (6 percent), cerebrovascular accidents (1 percent), transient ischemic attacks (3.1 percent), and myocardial infarctions (2 percent) were not significantly influenced by intraoperative local anesthetic injection of the carotid sinus nerve. Intraoperative and postoperative hypotension did not cause morbidity in this series, however, local anesthetic injection was associated with a significant incidence of perioperative hypertension. Routine prophylactic local anesthetic injection of the carotid sinus nerve cannot be recommended in view of its detrimental effects in relation to the development of hypertension.

Spindle cell carcinoma of the breast: case report and review.

Spindle cell carcinoma is a distinct, but unusual, variant of squamous cell carcinoma. It is seen most frequently in the upper aerodigestive tract and esophagus. The natural history seems to be similar to that of the more typical squamous cell carcinoma. A case of spindle cell carcinoma arising from the ductal epithelium of the breast is reported. The light and electron microscopic histology is described. A review of the literature suggests that this rare neoplasm should be managed in a fashion similar to that for more common types of epithelial breast duct malignancies.

The use of computed tomography in the evaluation of mediastinal masses.

A retrospective analysis was conducted to ascertain whether computed tomography had increased diagnostic accuracy while decreasing the number of tests needed in the preoperative assessment of patients with mediastinal masses. A total of 42 patients were entered into the study: Fifteen patients were evaluated before the advent of computed tomography (No CT) and 27 patients had computed tomography during their evaluation (CT). The No CT group comprised 10 male and five female patients (2:1 ratio); the age range was 8 months to 61 years. The CT group included 15 male and 12 female patients (1.25:1.0 ratio), the age range being 21 to 70 years. In each group, both invasive and noninvasive studies were done. Although the CT group had 40 noninvasive tests, 27 were computed tomographic scans. The additional 13 noninvasive tests and the five invasive tests added no significant diagnostic information. In the No CT group, preoperative evaluation as to the cystic or solid nature of the mass was correct only four of 13 times (31%). In the CT group, 22 of 25 patients had accurate assessment as to the cystic or solid nature of the lesions (88%). In addition, extension of the mass into other structures, consistent with malignancy, was correctly diagnosed preoperatively in nine of the patients in the CT group. Two had extension of the mass at operation not preoperatively diagnosed (82% accuracy). None of the No CT group was given an assessment of possible mass extension preoperatively. The results suggest that mediastinal masses can be evaluated by computed tomography with a high degree of accuracy for predicting the nature, size, location, and involvement of other organs by the mass. The use of other tests before resection generally yields little additional information.

The noninvasive diagnosis of vasculogenic impotence.

One hundred eleven impotent men and 25 potent men were prospectively evaluated with a standardized exercise treadmill test (SETT) used to noninvasively define their pelvic hemodynamics. Fifty-six men had vasculogenic impotence, whereas the remaining 55 had erectile dysfunction resulting from undetermined causes (31), psychogenic factors (10), or other identifiable reasons (14). Arteriography was performed on 40 (71%) of the patients with vasculogenic impotence without false positive results, as well as in 11 (44%) of the potent control patients and in six (11%) of the patients with nonvasculogenic impotence without false negative results, confirming the validity of the SETT. The distinction between vasculogenic and nonvasculogenic impotence can be accurately made with the SETT. Patients with vasculogenic impotence had a resting penile-brachial index (PBI) equal to 0.60 +/- 0.022 (mean +/- SEM) and a PBI after exercise equal to 0.45 +/- 0.019 with a fall in the mean PBI of -0.15 (p less than 0.001). Patients with nonvasculogenic impotence had a resting PBI equal to 0.80 +/- 0.024 and a PBI after exercise equal to 0.88 +/- 0.019 with a rise in mean PBI of 0.08 (p less than 0.001). This response was not significantly different between the control group and the nonvasculogenic impotence patients. The addition of PBI determinations after treadmill exercise revealed that 18% of the patients with vasculogenic impotence would have been incorrectly diagnosed, because their resting PBI was greater than the traditional standard of 0.70. Furthermore, 18% of the patients with nonvasculogenic impotence would have been incorrectly diagnosed as having vasculogenic impotence because their resting PBI was less than 0.70.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphogenesis and clinicopathologic characteristics of recurrent carotid disease.

The histopathologic characteristics of primary plaques and recurrent carotid disease were studied in 32 patients. These data were related to symptoms, recurrence interval (6 to 176 months), arteriographic anatomy, and in situ operative findings. A striking predilection was noted for recurrent lesions to be located in the internal carotid artery near the origin, but still within the confines, of the original endarterectomy site and suture line. Although recurrence was frequently associated with a long primary arteriotomy, evidence of technical faults or periarterial fibrosis was rare. Early recurrent lesions (recurrence interval less than 36 months, n = 13) had significantly more smooth muscle cells and proteoglycans (p less than 0.001) than late recurrent lesions (recurrence interval greater than 36 months, n = 19). As previously reported, features of atherosclerosis (abundant collagen, calcium deposits, and foam cells) were more pronounced in late recurrences (p less than 0.001). However, the histopathologic differentiation between early and late recurrent carotid disease was indistinct. A continuum was noted whereby characteristics of late recurrent lesions increased in proportion to recurrence interval. All recurrent lesions were easily distinguished from primary plaques in that recurrences had a less orderly arrangement of all elements and lacked the classic topographic features of advanced atherosclerosis. An important feature that differentiated primary and recurrent lesions was the presence of surface and intraplaque thrombus in 90% of recurrent lesions (p less than 0.001). In early recurrent disease, luminal surface thrombus was striking; this was frequently platelet-rich and showed organization devoid of neovascularity. Intraplaque thrombus was more common in late recurrent disease, consisted almost entirely of fibrin, and was often contiguous with luminal surface thrombus. No discernible relationships were noted between thrombus associated with recurrent lesions and the presence or absence of symptoms, treatment with antiplatelet agents, and hypertension. This finding suggests that thrombus was a continuous and intrinsic component of recurrent disease rather than a secondary, complicating feature. Recurrent carotid disease is a progressive lesion that stems from ongoing thrombogenesis occurring at the endarterectomy site. Organized thrombus and smooth muscle cell proliferation comprise the bulk of the lesion, which undergoes atherosclerotic change with time.

Saccular renal artery aneurysm as a cause of hypertension.

The case of a patient with renovascular hypertension related to an arterial kink is reported. The arterial kink was caused by a renal artery aneurysm and was not apparent with angiography. This is the first reported case in which renin-mediated hypertension was clearly related to a correctable mechanical problem from a saccular renal artery aneurysm. Indications for surgical repair of renal artery aneurysms and angiographic findings indicative of a functionally significant renal artery stenosis are reviewed.

Wound hematomas after carotid endarterectomy.

Wound hematomas, following carotid endarterectomy, are uncommon but potentially lethal complications. The management of 13 patients with this condition is presented. Factors that appeared to predispose to hematoma formation included perioperative use of platelet inhibitory drugs and postoperative hypertension. When the diagnosis of neck wound hematoma is made after carotid endarterectomy, prompt evacuation under local anesthesia is recommended.

Management of patients with symptomatic extracranial carotid artery disease and incidental intracranial berry aneurysm.

Perioperative fluctuation of blood pressure and the use of anticoagulants during carotid endarterectomy may potentiate lethal aneurysm rupture in patients who have symptomatic extracranial carotid artery occlusive disease with incidental, asymptomatic, intracranial berry aneurysms. Ten patients having this combination are described in the present study. Of five men and five women whose mean age was 63 years, nine had symptomatic carotid bifurcation atherosclerosis, one had internal carotid fibromuscular dysplasia, and all had intracranial berry aneurysms ranging from 2 to 13 mm in diameter (mean diameter 6.6 mm). In seven patients, aneurysms were greater than or equal to 6 mm in diameter. Hypertension was present in seven patients and moderately severe in five. Three of the aneurysms were located in the intracranial internal carotid artery, five in the middle cerebral artery, three in the posterior communicating artery, one in the anterior cerebral artery, and one in the superior cerebellar artery. Twelve carotid reconstructive procedures were performed without morbidity related to aneurysm rupture. These included 10 carotid endarterectomies, one of which was combined with Dacron patch angioplasty and one of which was combined with a simultaneous coronary artery bypass; one carotid artery dilatation for fibromuscular disease; and one reoperative carotid endarterectomy with patch angioplasty. Three patients had correction of hemodynamically significant lesions, two of which were proximal to ipsilateral anterior circulation aneurysms. An intraluminal shunt and heparin anticoagulation therapy were used in all patients. Despite a concerted effort to control blood pressure, the patients' perioperative blood pressures ranged from 60/30 to 240/110 mm Hg. Three patients had subsequent elective clipping of intracranial aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)