Ultrafast x-ray scattering of xenon nanoparticles: imaging transient states of matter.

Femtosecond x-ray laser flashes with power densities of up to 10(14) W/cm(2) at 13.7 nm wavelength were scattered by single xenon clusters in the gas phase. Similar to light scattering from atmospheric microparticles, the x-ray diffraction patterns carry information about the optical constants of the objects. However, the high flux of the x-ray laser induces severe transient changes of the electronic configuration, resulting in a tenfold increase of absorption in the developing nanoplasma. The modification in opaqueness can be correlated to strong atomic charging of the particle leading to excitation of Xe(4+). It is shown that single-shot single-particle scattering on femtosecond time scales yields insight into ultrafast processes in highly excited systems where conventional spectroscopy techniques are inherently blind.

Infected Viabahn stent graft in the superficial femoral artery.

We present a case of an infected stent graft in the superficial femoral artery (SFA). A 67-year-old woman underwent excision of an infected Viabahn stent graft. At exploration there was no apparent artery around the majority of the stent graft, suggesting that the SFA had been autolysed. Infected stents and stent grafts are rare in the SFA position. The risk of infection is likely minimised with standard treatments including drainage of infection prior to stent graft placement and periprocedural antibiotic administration. Successful management will, in most cases, require excision of the stent graft and adjunctive arterial reconstruction, as necessary.

Prevalence of retinopathy in Caucasian type 2 diabetic patients from the South of Brazil and relationship with clinical and metabolic factors.

Diabetic retinopathy (DR) is a sight-threatening chronic complication of diabetes mellitus and is the leading cause of acquired blindness in adults. In this cross-sectional study, we investigated the prevalence of and the factors associated with DR in an analysis of 210 consecutive and unrelated Brazilian Caucasians with type 2 diabetes mellitus. Retinopathy was evaluated by ophthalmoscopy and/or biomicroscopy through dilated pupils. The relationship between clinical and metabolic variables and the presence of DR was assessed by logistic regression analysis. DR was detected in 99 of the 210 patients (47%). In the univariate logistic regression analyses, male sex, duration of diabetes, body mass index, glycated hemoglobin, C-peptide, LDL cholesterol, smoking, and albumin excretion rate were found to be associated with the presence of DR. However, the multiple logistic regression analysis showed that only duration of diabetes (odds ratio (OR) = 1.15, 95% CI = 1.09-1.22; P < 0.001), glycated hemoglobin (OR = 1.21, 95% CI = 1.01-1.46; P = 0.047) and albumin excretion rate > 100 microg/min (OR = 12.72, 95% CI = 3.89-41.56; P < 0.001) were independently associated with DR. Although DR was found to be frequent among Brazilian type 2 diabetic patients, its prevalence was within the range observed in other Caucasian populations. Our findings emphasize the need for good glycemic control in order to prevent or delay the onset of DR, since the most well-known risk factors for the development of this complication in type 2 diabetes mellitus, such as duration of diabetes, glycated hemoglobin and albumin excretion rate were independently related to DR.

The changing spectrum of cystic pulmonary lesions requiring surgical resection in infants.

Congenital labor emphysema and cystic adenomatoid malformation have been the most common surgically treatable cystic lesions of the lung. With the successful treatment of newborn respiratory distress syndrome, an increased frequency of an acquired form of cystic disease, interstitial pulmonary emphysema, has been observed. Some degree of interstitial pulmonary emphysema is relatively common, and during the years 1980 to 1983 this disease was diagnosed in 372 infants. Seven of these infants, all premature, underwent resection of relatively localized areas of persistent cystic interstitial pulmonary emphysema. Lobectomy or wedge resection was performed in five patients because of their inability to be weaned from the ventilator. A sixth patient with this disease underwent lobectomy for recurrent pneumothoraces. A seventh patient underwent lobectomy because the cystic interstitial pulmonary emphysema produced atelectasis and recurrent infections. All seven patients were extubated by the fourth postoperative day, have been discharged, and are showing respiratory improvement. Within the same period, four infants had congenital lobar emphysema and two had congenital cystic adenomatoid malformation. They were gestational age 36 weeks or older and, although respiratory distress was present to some degree in all six, only one was ventilator dependent at operation. All underwent lobectomy and one infant had a left upper lobe resection and right middle lobectomy on separate occasions for bilateral congenital cystic adenomatoid malformation. All patients with congenital labor emphysema and congenital cystic adenomatoid malformation have been discharged and are doing well. Our results suggest the following conclusions: Persistent interstitial pulmonary emphysema is now the most common indication for pulmonary resection in the newborn period. The anatomic distribution of resected interstitial pulmonary emphysema is similar to that of congenital lobar emphysema. Although only a small fraction (less than 2%) of patients with interstitial pulmonary emphysema require operation, the development of relatively large discrete cystic areas that (1) significantly decrease effective lung volume and produce respirator dependence, (2) produce atelectasis and recurrent infections, or (3) lead to pneumothoraces may make pulmonary resection beneficial. Finally, despite the presence of generalized lung disease in patients with interstitial pulmonary emphysema, these patients can be expected to improve significantly after resection, and the long-term outcome is generally good.

The pre-conditioning incidence of antiphospholipid antibodies is not significantly increased in patients with bone marrow transplant-related organ dysfunction.

Hepatic dysfunction resulting from hepatic veno-occlusive disease (VOD) is a common complication of bone marrow transplantation (BMT). Some investigators believe that hepatic dysfunction, along with pulmonary and central nervous system (CNS) dysfunction, is part of a systemic disorder called multiple organ dysfunction syndrome (MODS). Endothelial damage by pretransplant chemo-radiation and activation of hemostasis are considered early events in the development of hepatic VOD. The pathological mechanism leading to fibrous obliteration of hepatic vessels may also take place in pulmonary and CNS vessels. Since antiphospholipid antibodies (aPA) are associated with venous and arterial thrombosis, which can lead to vessel occlusion, we asked if the incidence of aPA before conditioning was greater in patients who developed MODS following BMT. Samples drawn before pretransplant chemo-radiation from 57 patients who subsequently developed MODS and 55 control patients who did not develop MODS were studied blindly for aPA by ELISA. The number of aPA-positive patients who developed MODS (10/57), compared to the number of aPA-positive patient controls who did not develop MODS (7/55) was not statistically significant (P = 0.48). Our data indicate that the incidence of aPA before conditioning was not greater in patients who developed MODS, including hepatic VOD, following BMT.

Limb salvage despite extensive tissue loss. Free tissue transfer combined with distal revascularization.

Extensive lower-extremity tissue loss may preclude limb salvage despite successful arterial reconstruction. We attempted to avoid limb loss in such patients by combining arterial bypass with microvascular free tissue transfer. Fourteen patient (12 diabetic), 33 to 74 years of age, presented with extensive tissue loss in 15 lower extremities, exposing bone or tendon on the heel, ankle, lower part of the leg, or hindfoot. Mean ulcer size was 5 X 8 cm. Four patients had had previous contralateral below-knee amputations. Femorodistal (seven), popliteal-distal (three), or femoropopliteal (four) bypass, or tibial angioplasty (one), was performed to provide sufficient inflow for free tissue transfer. Serratus anterior, scapular, latissimus dorsi, rectus abdominis, gracilis, ulnar, or temporalis free flaps were used. One free flap failed due to venous thrombosis and was corrected with a second flap. Limb salvage was achieved in 14 (93%) of 15 limbs during a mean follow-up of 24 months. The single amputation occurred due to severe foot ischemia in a patient whose femorodistal bypass remained patent only to the viable free flap. The remaining 13 patients (14 limbs) became ambulatory, including those with free flaps to weight-bearing regions.

Telemetered temperature monitoring in preweanling Mongolian gerbils (Meriones unguiculatus).

Like most small mammals, Mongolian gerbils (Meriones unguiculatus) are born without the ability to maintain core body temperature (Tb). Breeding adults, juvenile alloparents, nest materials, and other litter mates probably contribute to the maintenance of core body temperature in neonates, but the relative role of each factor is unknown. We developed a procedure allowing biotransmitters to be implanted into 9-day-old pups for use with a radiotelemetry system. Experiment 1 demonstrated the development of thermoregulatory capacity over postpartum days 11, 15, and 19. Pups at 11 days of age lacked thermoregulatory capacity, and maintained Tb only slightly above the ambient temperature (15 degrees C) of the testing environment. The transition from poikilothermy to homeothermy was clearly accomplished by day 19, with pups maintaining Tb of 35.8 +/- 0.2 degrees C for at least 100 min. Experiment 2 measured Tb in 11- and 12-day-old pups during a thermal challenge (15 degrees C) in the presence of nest materials, litter mates, or both. Pups provided with either nest materials, litter mates, or both maintained higher Tb during a 40-min test than those without these resources. Our methodology minimizes disruptions and the thermal consequences associated with other invasive (rectal probe thermistors) and noninvasive (e.g., infrared thermography) procedures.

Assessment of coagulation system activation using spot urine measurements.

Coagulation system activation is most commonly assessed by measuring levels of one or more proteins in peripheral blood. Because faulty blood-drawing can cause activation of the coagulation system, artifactual elevations of such markers have been reported. We have therefore investigated the possibility of using randomly collected ('spot') urine samples as a non-invasive means of assessing the state of coagulation system activation. Using a commercially available enzyme-linked immunosorbent assay kit designed to measure plasma levels of fragment 1 + 2, we found immunoreactive fragment 2 in healthy control subjects, and significantly increased levels in diabetic and non-diabetic pregnant subjects, and patients with venous thromboembolism, prostate cancer, and diabetes. Measurements of excretion of immunoreactive fragment 2 are worth further study as an adjunct or alternative to plasma-based assays designed to detect or quantify coagulation system activation.

Experimental freeze-dried microarterial allografts in rabbits.

Arterial allografts, 3.5 cm in length, were freeze-dried and placed into the femoral arteries of 20 female rabbits (16 experimental subjects and four controls). Immediate patency was 100%. Subjects were surgically explored after two months of observation. Overall patency at this time was 31% (5/16). A patency rate of 50% (5/10) was achieved with size-matched femoral grafts. However, all of the smaller diameter brachial grafts were unsuccessful. Analysis by light microscopy as well as transmission and scanning electron microscopy demonstrated intimal hyperplasia, which was more prominent in nonpatent grafts. There was no evidence of a cellular immune response to the freeze-dried grafts by the host. The use of size-matched grafts and postoperative anticoagulants in future studies may improve patency rates and the potential clinical applicability of this promising microvascular technique.

Aortoiliac occlusive disease.

The effects of gender on patient selection and results of intervention for aortoiliac atherosclerotic occlusive disease have received little attention in published reports. Review of our experience with aortobifemoral, femorofemoral, and axillofemoral bypass identified consistently more isolated anatomic aortoiliac disease in women, but virtually indistinguishable levels of preoperative ischemia as measured by clinical and hemodynamic indices. The performance of each of these three methods of reconstruction did not appear to be affected by gender. Review of other investigators' experience with these techniques as well as unilateral aortofemoral bypass, iliofemoral bypass, and PTBA did not find any evidence of discrepant performance of these latter techniques in women and men. This is in contrast to the results with infrainguinal reconstruction, which in our hands appear to be inferior in women. Concerns that results of aortoiliac reconstruction would be inferior in women due to small arteries or other differences appear unfounded. Women may be less likely to receive a recommendation for intervention for nonlimb-threatening ischemia due to gender biases on the part of the patient, primary physician, or vascular specialist, just as they are clearly less likely to be considered for intervention for coronary artery atherosclerosis. Our observations suggest that these biases are unfounded when formulating recommendations for women with aortoiliac atherosclerotic occlusive disease.

Which asymptomatic patients should have carotid endarterectomy?

Carotid endarterectomy for asymptomatic very-high-grade stenosis has been shown to be of clear benefit when compared with best medical treatment in recent prospective randomized studies. However, the benefit of carotid endarterectomy in these trials has been less than most vascular surgeons predicted based on prior nonrandomized studies. Furthermore, vascular surgeons often see patients who do not fit the inclusion criteria for any of the prospective randomized trials and whose potential benefit from endarterectomy may be different from that observed in those trials. Medical comorbidities or other patient characteristics that suggest even small increases in risk for carotid endarterectomy may negate the marginal benefit of the procedure in asymptomatic patients. Potential benefit is also highly dependent on surgeon-specific and hospital-specific perioperative morbidity and mortality. This article addresses some of the factors that may alter the potential benefit of carotid endarterectomy and the implications with respect to recommendations for or against carotid endarterectomy in the individual patient.

The role of extraanatomic bypass in the management of bilateral aortoiliac occlusive disease.

Axillofemoral bypass is a hemodynamically inferior reconstruction that should be performed only in high-risk patients. In view of the apparent inferior patency and hemodynamic performance when compared with aortofemoral bypass, axillofemoral bypass should not be performed for claudication except in truly disabled, low-risk patients whose contraindication to aortofemoral bypass is a "hostile abdomen." Some of these patients might be candidates for extraperitoneal iliofemoral bypass, thoracofemoral bypass, or other procedures that would probably provide hemodynamically superior results. Axillofemoral bypass produces acceptable hemodynamic results, patency, and limb salvage in high-risk patients with limb-threatening ischemia and limited life-expectancy. Despite overall inferior results, relief of initial symptoms is nearly always achieved and few patients require amputation before death. Axillofemoral bypass will remain an important option in such patients. In general, we continue to favor axillobifemoral reconstructions when symptoms are significantly bilateral. However, we do not hesitate to perform axillounifemoral bypass when symptoms and disease are unilateral and alternative unilateral inflow operations are not appropriate. Outcome of operations is clearly influenced by patient selection, and this must be considered when interpreting published results. It is likely that axillofemoral bypass will continue to be a critical tool for vascular surgeons faced with desperately ill patients at risk of limb loss due to bilateral aortoiliac inflow disease. As the operative risk of aortofemoral and iliofemoral bypass continues to decrease, the admonition that a significant number of long-term survivors should prompt the surgeon to ask whether she or he is performing axillofemoral bypass when another procedure might be more appropriate is probably more true today than when DeLaurentis et al first made the following statement: If indeed this operation is designed for poor risk cardiopulmonary patients threatened with loss of limb and a short life expectancy rate, we should not expect to see reports of patients with long term survival rates.

Case report. Plasmacytoma presenting as unilateral proptosis.

A 49-year-old man presented with proptosis of the right eye. An x-ray film of the skull showed a lytic lesion in the right frontal bone. No other skeletal lesions were found. Immunoelectrophoretic analysis showed a monoclonal elevation of IgG level. A soft orbital tumor near the foramen of the optic nerve was removed and found to be a plasmacytoma. The patient was given local irradiation. When IgG level increased about four months after surgery, he was treated with chemotherapy. IgG level decreased and no further skeletal lesions were found.

Association between the presence of protein bands in ram seminal plasma and sperm tolerance to freezing.

This study evaluated associations between the presence of protein bands in ram seminal plasma and the quality of sperm frozen with distinct extenders. Ejaculates were frozen in a Tris-egg yolk based extender, including either 5% glycerol or 100mM trehalose. Seminal plasma samples were submitted to unidimensional electrophoresis. Pre-freezing and post-thawing sperm quality was similar between extenders (P>0.05). A total of 26 bands were identified in ram seminal plasma. Pre-freezing sperm motility was increased when the 15, 19 and 80kDa bands were present in seminal plasma (P<0.05). The presence of an 11kDa band in seminal plasma was associated with reduced pre-freezing membrane integrity (P<0.05). After thawing, both sperm motility and membrane integrity were reduced when a 24kDa band was present in seminal plasma (P<0.05). Post-thawing acrosome integrity was greater in the presence of a 31kDa band in seminal plasma (P<0.05). Regardless of the cryoprotectant included in the freezing extender, these six bands may be potential markers for ram sperm tolerance to freezing.