Prevalence and clinical significance of posterolateral thigh perforator vein incompetence

PURPOSE: Posterolateral thigh perforator (PLTP) veins are part of the lateral thigh venous system, which in most people remains undeveloped. This study was designed to determine the prevalence and clinical significance of these veins. METHODS: Over the past 6 years, 2820 lower limbs with signs and symptoms of chronic venous disease (CVD) were evaluated for venous reflux using color flow duplex imaging. Superficial, perforating, and deep veins were examined in the standing, sitting, and reversed Trendelenburg positions. PLTP veins were best identified in the standing position with the patient facing away from the examiner. RESULTS: Twenty-six incompetent PLTP veins were found in 24 limbs (0.85%) of 21 patients (mean age, 43 +/- 16 years; range, 22 to 77 years). All PLTP veins pierced the fascia lata 12 to 25 cm (mean, 16 +/- 3 cm) above the popliteal skin crease in the lateral aspect of the thigh. At this level, the PLTP veins dove posteriorly 3 to 8 cm to join primarily tributaries of the deep femoral vein, superficial femoral vein, or both. Eight PLTP veins were duplicated at 1 to 2 cm below the fascia. Seven PLTP veins gave rise to superficial tributaries that were extended to the lower lateral and posterior thigh, whereas the remaining 19 PLTP veins gave rise to tributaries alongside the lesser saphenous vein and the anterior arch of the greater saphenous vein. On nine occasions, reflux was found in the PLTP veins and their associated tributaries alone. In all of these cases, reflux was adequately controlled with a tourniquet placed distal to the fascial defect. In the remaining 17 PLTP veins, reflux was also seen in the greater saphenous vein, the lesser saphenous vein, or both. None of the limbs that had PLTP vein reflux alone exceeded CVD class 3. When PLTP vein reflux was combined with saphenous reflux, there were five limbs classified as CVD class 4 and one limb each as CVD classes 5 and 6. Twenty limbs underwent ligation and stripping of the varicosities. Three of the earlier patients in the series underwent incomplete operations, which resulted in immediate residual varicosities from the PLTP tributaries. All three patients underwent reoperation successfully within a year. CONCLUSIONS: The prevalence of PLTP vein reflux is quite low. Reflux in the PLTP veins alone is associated with mild to moderate clinical presentation. However, when it is combined with saphenous reflux skin damage can be present. Failure to recognize PLTP veins may result in an incomplete or unnecessary operation, leaving the patients with residual varicose veins.     

Excision of Ds1 from the genome of maize streak virus in response to different transposase-encoding genes

Reliability and validity of direct visual analogue scale (VAS) ratings of improvement were assessed in 162 patients with Seasonal Affective Disorder, Winter Depression type (W-SAD), after light treatment for 6 consecutive days. The patients were rated with the Montgomery-Asberg Depression Rating Scale (MADRS) and a scale for the 'atypical' symptoms hypersomnia, hyperphagia and carbohydrate craving (the ATYP scale) before and after treatment. After treatment the patients also self-rated their global improvement on a 10-cm VAS, with anchoring points of 'No improvement' and 'Complete improvement'. VAS ratings were repeated several times, with 1-4 weeks between assessments, in a follow-up period, always referring to improvement in relation to baseline, and accompanied by a statement whether there had been any change since the former VAS rating. Shortly after treatment there was a mean reduction of 59.8% on the MADRS and 57.1% on the ATYP score, and 58.4% improvement as measured by the VAS. VAS rating correlated highly with percentage reduction of MADRS scores (r=0.85) and somewhat less with reduction of ATYP scores (r=0.64). VAS ratings in the follow-up period showed an extremely high test-retest reliability (r=0.96) for two consecutive ratings between which the patient stated that there had been no definite change. The results support the use of VAS ratings for assessment of global improvement after light treatment in patients suffering from W-SAD; use in other kinds of depression and with other types of treatment remains to be explored.     

Quantitative gated single photon emission computed tomography imaging: a counts-based method for display and measurement of regional and global ventricular systolic function

There is a considerable amount of data indicating that several major unfavorable cerebrovascular events are not randomly distributed over time, but show a peculiar distribution along the day, the week, and the months of the year. The authors review the available evidence on the chronobiological (circadian, weekly, and seasonal) patterns of onset of acute cerebrovascular diseases and variations in their possible triggering mechanisms. The existence of a peculiar chronobiological pattern in the onset of acute cerebrovascular disease, characterized by both circadian (morning and evening occurrence), circaseptan (last and first days of the week), and circannual (especially in winter) is confirmed, although differences depending on biological (gender, age), pathological (diabetes, hypertension, smoke, alcohol), cultural, social, and environmental factors exist. A deeper knowledge of the underlying pathophysiologic mechanisms could provide more effective insights for both preventive strategies and optimization of therapeutic approach.     

Identification and localization of slow, natural, cooperative unfolding in the hematopoietic cell kinase SH3 domain by amide hydrogen exchange and mass spectrometry

Protein unfolding on a fast time scale (milliseconds-minutes) has been widely reported, but slower unfolding events (10 min-hours) have received less attention. Amide hydrogen exchange (HX) and mass spectrometry (MS) were used to investigate the unfolding dynamics of the hematopoietic cell kinase (Hck) SH3 domain. Analysis of mass spectra after deuterium exchange into intact Hck SH3 indicates a cooperative unfolding event involving 24-61% of the domain and occurring with a half-life of approximately 20 min under physiological conditions. To identify the unfolding region, SH3 was incubated in D2O and proteolytically fragmented into peptides that were analyzed by mass spectrometry. Correlation of HX rates and isotope patterns reveals cooperative unfolding in several regions, including the C-terminal half of the RT-loop and a beta-sheet flanking the binding site. Binding of a prolyl-rich segment from the HIV Nef protein slows unfolding by a factor of 3. Further analysis yields a KD of 25 microM for the Nef peptide. These results demonstrate that an inherent flexibility in the SH3 domain may assist interconversion of the closed, intramolecularly ligated state and the open, active state of Src family kinases. Furthermore, this type of previously undetectable, slow unfolding process may provide the basis for new mechanisms in which kinetics of local unfolding combines with thermodynamics to regulate enzymatic activity. The combination of hydrogen exchange and mass spectrometry appears to be the only general method capable of examining these slow unfolding processes.     

A homologue of Drosophila aurora kinase is oncogenic and amplified in human colorectal cancers

Genetic and biochemical studies in lower eukaryotes have identified several proteins that ensure accurate segregation of chromosomes. These include the Drosophila aurora and yeast Ipl1 kinases that are required for centrosome maturation and chromosome segregation. We have identified two human homologues of these genes, termed aurora1 and aurora2, that encode cell-cycle-regulated serine/threonine kinases. Here we demonstrate that the aurora2 gene maps to chromosome 20q13, a region amplified in a variety of human cancers, including a significant number of colorectal malignancies. We propose that aurora2 may be a target of this amplicon since its DNA is amplified and its RNA overexpressed, in more than 50% of primary colorectal cancers. Furthermore, overexpression of aurora2 transforms rodent fibroblasts. These observations implicate aurora2 as a potential oncogene in many colon, breast and other solid tumors, and identify centrosome-associated proteins as novel targets for cancer therapy.     

Cell-cell association directed mitotic spindle orientation in the early development of the marine shrimp Sicyonia ingentis

During early cleavages of Sicyonia ingentis embryos, mitotic spindle orientations differ between blastomeres and change in a predictable manner with each successive mitosis. From 2nd through 7th cleavages, spindles orient at a 90 degrees angle with respect to the spindle of the parent blastomere. Thus, spindle orientation is parallel to the cleavage plane that formed the blastomere. To determine if specific spindle orientations were intrinsic properties of individual blastomeres, we altered blastomere associations and asked how mitotic spindle orientation was affected in successive cleavages using laser scanning confocal microscopy. Linear embryos were constructed by dissociating 4-cell embryos and recombining the blastomeres in a linear array. The ensuing cleavage (3rd embryonic cleavage) of these linear embryos was parallel to the long axis of the embryo, resulting in four parallel pairs of blastomeres which lay in a common plane that was parallel to the substratum. The 4th cleavage produced a linear embryo with the 16 blastomeres arranged in four parallel quartets. Then, in preparation for 5th cleavage, spindles oriented at a 45 degrees angle (not parallel as in normal development) with respect to the previous cleavage plane. When 8-cell linear embryos were separated into linear half-embryos, subsequent spindle orientations were not like those observed for intact 8-cell linear embryos, but rather regressed to the orientation seen in 4-cell linear embryos. We suggest that the reorientation of mitotic spindles during early cleavage of S. ingentis is neither an intrinsic property nor age dependent, but rather is cell contact related. Further, these results in conjunction with observations of non-manipulated embryos suggest that spindle poles (centrosomes) avoid cytoplasmic regions adjacent to where there is cell-cell contact during early development.     

Comprehensive management of Raynaud's syndrome

Raynaud's syndrome stands as a landmark to our ignorance of the mechanisms involved in the interrelationship of the central nervous system and peripheral circulatory physiology. Proper management for these unfortunate patients demands an integrated comprehensive effort of the pharmacologic, physical medical, and surgical disciplines.     

A new approach to robust beamforming in the presence of steeringvector errors

This correspondence presents a new approach to array beamforming in the presence of steering vector errors, such as steering angle and carrier frequency errors. The basic idea is based on the principle that the output power of an optimized beamformer achieves a local maximum if the steering vector coincides with that of the desired signal. The proposed approach iteratively searches for the correct steering vector by maximizing the array mean output power using a first-order Taylor series approximation of the steering vector in terms of the steering errors. This method has the advantages of easy implementation and suffers no loss in the degrees of freedom for interference rejection. Furthermore, the method is independent of the choice of the phase center coordinate origin contrary to derivative constraint methods. Conditions for the existence of a solution using the proposed method are also established     

Crystallization studies of the β (Mg2Pb) phase and its phase boundaries in the Pb-Mg-Bi system

A peritectic reaction between Mg bismuthide and Mg plumbide changes from an even to an odd reaction at 310 °C (0.14 wt pct Bi and 4 wt pct Mg) owing to the incorporation of 1.6 wt pct Bi into Mg plumbide; this value was calculated from material balances of equilibrium studies of this reaction and confirmed by direct analysis of crystals using a “Cameca Microbeam” electroprobe microanalyzer. A model is presented in which an atom of Pb in the unit cell, 46 Mg₂Pb Mg₂Pb₅, is replaced by an atom of Bi which gives a concentration of 1.63 to 1.71 wt pct Bi depending on the actual species of Mg plumbide present. The phase boundary for double saturation with Pb and Mg plumbide, established from the data of equilibrium tests, shows a minimum temperature of 251.8 °C at 0.008 wt pct Bi and 2.2 wt pct Mg. Alloys in the primary Pb phase field adjacent to this boundary show undercooling to less than 248.5 °C followed by one or two sharp temperature increases to 250.5 °C, with the initiation of the removal of Bi when double saturation occurs giving a final liquid phase containing less than 0.001 wt pct Bi. Crystallization paths for alloys in the Mg plumbide phase field show a catatectic reaction and polymorphic transformations in the intermetallic compound. The removal of Bi is dependent on the concentration of Bi and Mg in the initial alloy. In systems containing sufficient Mg, a final alloy containing less than 0.001 wt pct Bi can be produced, and these conditions have been used as the starting point for the development of a process for the removal of Bi from Pb. Finally, the crystallization paths show there is a change in the thermal properties of the liquid alloy at 0.008 wt pct Bi which is independent of the temperature and concentration of Mg, and further work is required to resolve this finding.