The ostial valve of the great saphenous vein

Background

Venous valves have been classified into parietal (PVs) and ostial valves (OVs). PVs are located within the lumen of veins, whereas the OVs are located directly at the confluence of two veins. In the common femoral vein (CFV), the most prominent PVs are the suprasaphenic and infrasaphenic valve. The terminal valve (often designated as ‘valvule ostiale’ in the relevant literature in French) defined as that lying between the orifice of the great saphenous vein (GSV) and the most proximal of the major superficial tributary veins and the preterminal valve represent the most important PVs in the GSV. While PVs are well studied, there is not much literature on the OVs of the superficial venous system, especially of the GSV.

Objective

In order to investigate the presence of OVs (defined strictly as valves located at the entrance of a tributary vein) in the GSV, we carried out studies on specimens obtained from bodies bequested to the Division of Clinical and Functional Anatomy of Innsbruck Medical University.

Methods

Ninety-eight specimens consisting of the CFV and the attached tributary veins including the GSV were investigated.

Results

In five of these (5.1%), a single-cusped OV, in six (6.1%) a two-cusped OV and in 10 (10.2%) remnants of an OV were identified. Thus, OVs do not seem to be primarily present in all GSVs.

Conclusion

The distinction between PVs and OVs is not always clear in literature, and as a consequence misinterpretations may occur. Very often the terminal valve of the GSV, which is in fact a PV, is designated as an ‘ostial valve’. In view of its widespread use, we suggest that the term ‘ostial valve’ together with its clear description be included in the consensus documents of the ‘Union Internationale de Phlébologie’.

Saxagliptin, a potent, selective inhibitor of DPP-4, does not alter the pharmacokinetics of three oral antidiabetic drugs (metformin, glyburide or pioglitazone) in healthy subjects

AIM

To evaluate the pharmacokinetic interactions of the potent, selective, dipeptidyl peptidase-4 inhibitor, saxagliptin, in combination with metformin, glyburide or pioglitazone.

METHODS

To assess the effect of co-administration of saxagliptin with oral antidiabetic drugs (OADs) on the pharmacokinetics and tolerability of saxagliptin, 5-hydroxy saxagliptin, metformin, glyburide, pioglitazone and hydroxy-pioglitazone, analyses of variance were performed on maximum (peak) plasma drug concentration (C(max)), area under the plasma concentration-time curve from time zero to infinity (AUC(∞)) [saxagliptin + metformin (study 1) and saxagliptin + glyburide (study 2)] and area under the concentration-time curve from time 0 to time t (AUC) [saxagliptin + pioglitazone (study 3)] for each analyte in the respective studies. Studies 1 and 2 were open-label, randomized, three-period, three-treatment, crossover studies, and study 3 was an open-label, non-randomized, sequential study in healthy subjects.

RESULTS

Co-administration of saxagliptin with metformin, glyburide or pioglitazone did not result in clinically meaningful alterations in the pharmacokinetics of saxagliptin or its metabolite, 5-hydroxy saxagliptin. Following co-administration of saxagliptin, there were no clinically meaningful alterations in the pharmacokinetics of metformin, glyburide, pioglitazone or hydroxy-pioglitazone. Saxagliptin was generally safe and well tolerated when administered alone or in combination with metformin, glyburide or pioglitazone.

CONCLUSIONS

Saxagliptin can be co-administered with metformin, glyburide or pioglitazone without a need for dose adjustment of either saxagliptin or these OADs.

A new simplified sonographic approach for pararadicular injections in the lumbar spine: a CT-controlled cadaver study

BACKGROUND AND PURPOSE

Injection therapies play a major role in the treatment of lower back pain and are to date performed mainly under CT or fluoroscopic guidance. The benefits of US-guided instillation procedures have been shown in many studies. We conducted this study to simplify an US-guided approach to the lumbar spinal nerves and to assess the feasibility and preliminary accuracy by means of CT and anatomic dissection.

MATERIALS AND METHODS

Ten US-guided injections at 5 different levels (L1-L5) were performed on 1 embalmed cadaver. Images in 3 sagittal/parasagittal scanning planes were obtained at each lumbar level: 1) the plane of the spinous processes, 2) the plane of the lumbar arches/zygapophyseal-joints, and 3) the plane of the transverse processes. The PAP was then defined by positioning the transducer perpendicularly over the medial part of the respective transverse processes, depicting the hyperechoic intertransverse ligament. In the "in-plane technique," spinal needles were advanced through the respective segmental intertransverse ligament. A solution consisting of a contrast agent and a pigmented dispersion was subsequently injected into the pararadicular compartment. An anatomic dissection of the specimen and CT scans were performed to verify the exact placement of the needle tips and to evaluate fluid dispersion in the punctured compartment.

RESULTS

CT examination confirmed that each needle tip was correctly placed within the intended compartment with sufficient contrast accumulation around the respective proximal segment of the spinal nerve. On each anatomic section, dye was identified in the correct compartment and directly around each targeted spinal nerve with needles shown in the correct position.

CONCLUSIONS

This modified US approach for therapeutic root injections in the lumbar spine by using the intertransverse ligament as a new anatomic landmark allows an easy and correct needle placement within the pararadicular compartment.

Relative finger position influences whether you can localize tactile stimuli

To investigate whether the relative positions of the fingers influence tactile localization, participants were asked to localize tactile stimuli applied to their fingertips. We measured the location and rate of errors for three finger configurations: fingers stretched out and together so that they are touching each other, fingers stretched out and spread apart maximally and fingers stretched out with the two hands on top of each other so that the fingers are interwoven. When the fingers contact each other, it is likely that the error rate to the adjacent fingers will be higher than when the fingers are spread apart. In particular, we reasoned that localization would probably improve when the fingers are spread. We aimed at assessing whether such adjacency was measured in external coordinates (taking proprioception into account) or on the body (in skin coordinates). The results confirmed that the error rate was lower when the fingers were spread. However, there was no decrease in error rate to neighbouring fingertips in the fingers spread condition in comparison with the fingers together condition. In an additional experiment, we showed that the lower error rate when the fingers were spread was not related to the continuous tactile input from the neighbouring fingers when the fingers were together. The current results suggest that information from proprioception is taken into account in perceiving the location of a stimulus on one of the fingertips.

Valves of the gonadal veins

Purpose: Varicocele seems not to rely on the number of valves within the pampiniform plexus, the initial failure might be located on a higher level. Therefore, the failure should also occur in females. There is a comparable disease, Pelvic congestion syndrome, as result of pelvic venous engorgement due to gross dilatation and incompetence of ovarian veins.

Thus, we need a detailed description of venous course, branching as well as frequencies and locations of valves within both genders. Page 3/23

Material and Methods: In 31 Caucasian formalin-fixed bodies (15 males, 16 females) we investigated course and valves from Ovaries or internal inguinal ring, respectively, up to termination into inferior vena cava or left renal vein, respectively. Specimens were documented photographically and by a distinct protocol.

Results: In general, we found one valve on each side (testicular vein right 41.93%, left 51.52%; ovarian vein right 51.61%, left 45.45%). Two specimens had two valves per vein, each in a left testicular vein, and 15 veins showed absent valves. Valves existed between 0.0–4.5 cm, mainly 0.0–1.0 cm. One corpse showed varicose ovarian veins.

Conclusion: If veins show varices, one would expect missing valves or insufficient function. In contrast, none of our 15 valve-less veins showed varices or even enlargement. Also surprising, the only case with varices had one valve on each side. The terminal segment in both genders was almost identical and the venous course was similar. Precisely: men frequently had (N=11) less valves then women (N=4).

The use of proprioception and tactile information in haptic search

To investigate how tactile and proprioceptive information are used in haptic object discrimination we conducted a haptic search task in which participants had to search for either a cylinder, a bar or a rotated cube within a grid of aligned cubes. Tactile information from one finger is enough to detect a cylinder amongst the cubes. For detecting a bar or a rotated cube amongst cubes touch alone is not enough. For the rotated cube this is evident because its shape is identical to that of the non-targets, so proprioception must provide information about the orientation of the fingers and hand when touching it. For the bar one either needs proprioceptive information about the distance and direction of a single finger's movements along the surfaces, or proprioceptive information from several fingers when they touch it simultaneously. When using only one finger, search times for the bar were much longer than those for the other two targets. When the whole hand or both hands were used the search times were similar for all shapes. Most errors were made when searching for the rotated cube, probably due to systematic posture-related biases in judging orientation on the basis of proprioception. The results suggest that tactile and proprioceptive information are readily combined for shape discrimination.

Haptic search is more efficient when the stimulus can be interpreted as consisting of fewer items

In a typical haptic search task, separate items are presented to individual fingertips. The time to find a specific item generally increases with the number of items, but is it the number of items or the number of fingers that determines search time? To find out, we conducted haptic search experiments in which horizontal lines made of swell paper were presented to either two, four or six of the participants' fingertips. The task for the participant was to lift the finger under which they did not feel (part of) a line. In one of the conditions separate non-aligned lines were presented to the fingertips so that the number of items increased with the number of fingers used. In two other conditions the participants had to find an interruption in a single straight line under one of the fingertips. These conditions differed in the size of the gap. If only the number of items in the tactile display were important, search times would increase with the number of fingers in the first condition, but not depend on the number of fingers used in the other two conditions. In all conditions we found that the search time increased with the number of fingers used. However, this increase was smaller in the single line condition in which the gap was large enough for one finger to not make any contact with the line. Thus, the number of fingers involved determines the haptic search time, but search is more efficient when the stimulus can be interpreted as consisting of fewer items.

Haptic search with finger movements: using more fingers does not necessarily reduce search times

Two haptic serial search tasks were used to investigate how the separations between items, and the number of fingers used to scan them, influence the search time and search strategy. In both tasks participants had to search for a target (cross) between a fixed number of non-targets (circles). The items were placed in a straight line. The target's position was varied within blocks, and inter-item separation was varied between blocks. In the first experiment participants used their index finger to scan the display. As expected, search time depended on target position as well as on item separation. For larger separations participants' movements were jerky, resembling 'saccades' and 'fixations', while for the shortest separation the movements were smooth. When only considering time in contact with an item, search times were the same for all separation conditions. Furthermore, participants never continued their movement after they encountered the target. These results suggest that participants did not use the time during which they were moving between the items to process information about the items. The search times were a little shorter than those in a static search experiment (Overvliet et al. in Percept Psychophys, 2007a), where multiple items were presented to the fingertips simultaneously. To investigate whether this is because the finger was moving or because only one finger was stimulated, we conducted a second experiment in which we asked participants to put three fingers in line and use them together to scan the items. Doing so increased the time in contact with the items for all separations, so search times were presumably longer in the static search experiment because multiple fingers were involved. This may be caused by the time that it takes to switch from one finger to the other.

Living up to optimal expectations

Natural visual scenes contain several independent sources of information (cues) about a single property such as slant. It is widely assumed that the visual system processes such cues separately and then combines them with an averaging operation that takes the reliabilities of the individual cues into account. Does that mean that people lose access to information about inconsistencies between the cues, or are all inconsistencies revealed in a distorted surface appearance? To find out, we let observers match the slant and appearance of a simulated test surface to those of an identical, simultaneously visible, simulated reference surface and analyzed the variability in the settings. We also let observers match surfaces under conditions that were manipulated in ways that were expected to favor certain cues (monocular or binocular) or to selectively disrupt certain comparisons between the surfaces (slant or structure). The patterns in the variability between the settings were consistent with predictions based on the use of all available information. We argue that information about discrepancies is only "lost" during cue combination if there is no benefit in retaining the information.

Stemmer's (Kaposi-Stemmer-) sign – 30 years later

Background: Since the first description 30 years ago the Kaposi-Stemmer-sign is used consistently in the diagnostics of lymphoedema. Since then the original definition was extended or changed several times by other authors. Additionally, the underlying morphology of this clinical sign was not investigated. Material, methods: The second toes of both a patient with lymphoedema (stage III; iL5VxF5) and a healthy subject were compared sonographically, macroscopically and microscopically. Results: In lymphoedema both cutis and subcutis of the second toe were thickened, the structure of the dermal layers destroyed. An accumulation of oedematous fluid in free spaces within the subcutaneous tissue as well as lymphatic vessels could not be found. Discussion: The different definitions and graduations of the Kaposi-Stemmer-sign make the diagnosis of lymphoedema more difficult and concomitantly the clinical and scientific comparability. Morphologically, an accumulation of oedematous fluid could not be proven due to weak or missing streaks of fibrous tissue within the subcutis of the toe.

Ätiologie sekundärer Lymphödeme nicht onkologischer Genese

60% aller Lymphödeme entfallen auf sekundäre Lymphödeme, unter diesen liefern Neoplasien für über die Hälfte die Ursache; ein immer noch beträchtlicher Anteil entfällt damit auf sekundäre Lymphödeme nicht onkologischer Genese. Mit dieser Arbeit wird versucht, einen Überblick über die verschiedenen, in der Literatur erwähnten, Ätiologien dieses Formenkreises zu geben. Prinzipiell kann hier eine Gliederung in zwei Gruppen erfolgen: 1. Ursachen mit immunologischer Aktivität (z. B. Helminthen, Bakterien, Spirochäten, Viren, Pilze, allergische Kontaktdermatitis, Phlebitis, Rheumatoide Arthritis, Morbus Crohn); 2. Ursachen ohne immunologische Aktivität (z. B. Traumata, iatrogene Schäden, Pharmaka, Podokoniose). Hier wird einmal mehr ersichtlich, dass die Erkrankung Lymphödem aufgrund der großen Vielfalt der Ätiologien nicht einer einzelnen klinischen Disziplin untergeordnet werden kann, sondern vielmehr fächerübergreifend gesehen werden muss.

Visual depth processing in Williams–Beuren syndrome

Patients with Williams-Beuren Syndrome (WBS, also known as Williams Syndrome) show many problems in motor activities requiring visuo-motor integration, such as walking stairs. We tested to what extent these problems might be related to a deficit in the perception of visual depth or to problems in using this information in guiding movements. Monocular and binocular visual depth perception was tested in 33 patients with WBS. Furthermore, hand movements to a target were recorded in conditions with and without visual feedback of the position of the hand. The WBS group was compared to a group of control subjects. The WBS patients were able to perceive monocular depth cues that require global processing, but about 49% failed to show stereopsis. On average, patients with WBS moved their hand too far when no visual feedback on hand position was given. This was not so when they could see their hand. Patients with WBS are able to derive depth from complex spatial relationships between objects. However, they seem to be impaired in using depth information for guiding their movements when deprived of visual feedback. We conclude that the problems that WBS patients have with tasks such as descending stairs are not due to an inability to judge distance.

Judging relative positions across saccades

When components of a shape are presented asynchronously during smooth pursuit, the retinal image determines the perceived shape, as if the parts belong to the moving object that the eyes are pursuing. Saccades normally shift our gaze between structures of interest, so there is no reason to expect anything to have moved with the eyes. We therefore decided to examine how people judge the separation between a target flashed before and another flashed after a saccade. Subjects tracked a jumping dot with their eyes. Targets were flashed at predetermined retinal positions, with a 67-242 ms interval between the flashes. After each trial subjects indicated where they had seen the targets. We selected the trials on which subjects made a complete saccade between the presentations of the two targets. For short inter-target intervals, subjects' judgements depended almost exclusively on the retinal separation, even when there were conspicuous visual references nearby. Even for the longest intervals, only part of the change in eye orientation was taken into consideration. These findings cannot simply be accounted for on the basis of the mislocalisation of individual targets or a compression of space near saccades. We conclude that the retinal separation determines the perceived separation between targets presented with a short interval between them, irrespective of any intervening eye movements.

Adipose tissue at entheses: the rheumatological implications of its distribution. A potential site of pain and stress dissipation?

OBJECTIVES

To describe the distribution of adipose tissue within and adjacent to entheses in order to assess its functional significance at attachment sites.

METHODS

Entheses were removed from 29 different sites in the limbs of formalin fixed, elderly, dissecting room cadavers and the samples prepared for paraffin and/or methylmethacrylate histology. Entheses from four young volunteers with no history of significant musculoskeletal injury were examined by magnetic resonance imaging using T(1) weighted sequences.

RESULTS

Adipose tissue was present at several different sites at numerous entheses. Many tendons/ligaments lay on a bed of well vascularised, highly innervated, "insertional angle fat". Endotenon fat was striking between fascicles, where entheses flared out at their attachments. It was also characteristic of the epitenon, where it occurred in conjunction with lamellated and Pacinian corpuscles. Fat filled, meniscoid folds often protruded into joint cavities, immediately adjacent to attachment sites.

CONCLUSION

Adipose tissue is a common feature of normal entheses and should not be regarded as a sign of degeneration. It contributes to the increase in surface area of attachment sites, promotes movement between tendon/ligament and bone, and forms part of an enthesis organ that dissipates stress. The presence of numerous nerve endings in fat at attachment sites suggests that it has a mechanosensory role and this could account for the rich innervation of many entheses. Because damage to fat is known to lead to considerable joint pain, our findings may be important for understanding the site of pain in enthesopathies.

The "enthesis organ" concept: why enthesopathies may not present as focal insertional disorders

OBJECTIVE

The Achilles tendon insertion is associated with a complex of adjacent fibrocartilages, a bursa, and a fat-pad, and is functionally much more than a focal insertion. This has important implications for a better understanding of the spondylarthropathies (SpA). However, the degree to which other insertions form comparable "enthesis organs" has not been established. The aim of this study was to demonstrate the applicability of the enthesis organ concept to other insertion sites.

METHODS

Both joint-related (articular) and extraarticular entheses were removed from 28 sites in the limbs of formalin-fixed cadavers (age at death 70-101 years) that had been donated for anatomic study. The samples were prepared for paraffin histologic analysis and sectioned longitudinally. The presence and extent of enthesis organs was evaluated at each site in serial sections stained with Masson's trichrome and toluidine blue.

RESULTS

Articular enthesis organs were found at 14 entheses, including the attachments of the digital extensor tendons and collateral ligaments, the cruciate ligaments, tibialis anterior, the lateral collateral ligament of the knee, and the popliteal tendon. Extraarticular enthesis organs were seen at 2 sites, the biceps brachii and patellar tendon insertions. In all enthesis organs, sesamoid and/or periosteal fibrocartilage was present in close association with synovium.

CONCLUSION

The concept of an enthesis organ is of general significance in understanding attachment sites and may explain the diverse pathologic changes, including synovitis, bursitis, and extracapsular changes, seen adjacent to tendon/ligament entheses in SpA. These findings may provide insight into the reason the target tissues in SpA are apparently so diverse.