High-resolution optical coherence tomography as a non-destructive monitoring tool for the engineering of skin equivalents

BACKGROUND: Three dimensional skin equivalents are widely used in dermatopharmacological and toxicological studies and as autologous transplants in wound healing. In pharmacology, there is tremendous need for monitoring the response of engineered skin equivalents to external treatment. Transplantation of skin equivalents for wound healing requires careful verification of their quality prior to transplantation. Optical coherence tomography (OCT) is a non-contact, non-destructive imaging technique for living tissues offering the potential to fulfill these needs. This work presents an analysis of OCT for high-resolution monitoring of skin equivalents at different stages during the culture process. METHODS: We developed a high-resolution OCT imaging setup based on a commercially available OCT system. A broadband femtosecond laser light source replaces the original superluminescence diode. Tomograms of living skin equivalents were recorded with an axial resolution of 3 mum and correlated with histology and immunofluorescence images. Comparison with standard low-resolution OCT is presented to emphasize the advantages of high-resolution OCT for this application. RESULTS: OCT is particularly able to distinguish between different layers of skin equivalents including stratum corneum, epidermal and dermal layer as well as the basement membrane zone. The high-resolution OCT scans correlate closely with two key benchmarks, histology and immunofluorescence imaging. CONCLUSIONS: This study clearly demonstrates the benefits of high-resolution OCT for identifying living tissue structure and morphology. Compared with the current gold standard histology, OCT offers non-destructive tissue imaging, enabling high-resolution evaluation of living tissue morphology and structure as it evolves.     

Optimality in the developing vascular system: branching remodeling by means of intussusception as an efficient adaptation mechanism.

The theory of bifurcating vascular systems predicts vessel diameters that are related to optimality criteria like minimization of pumping energy or of building material. However, mechanisms for producing the postulated optimality have not been described so far, and quantitative data on bifurcation diameters during development are scarce. We used an embryonic vascular bed that rapidly grows and adapts to changing hemodynamic conditions, the chicken chorioallantoic membrane (CAM), and correlated vascular cast and tissue section morphology with in vivo time-lapse video monitoring. The bifurcation exponent delta and associated parameters were quantitatively assessed in arterial and venous microvessels ranging in diameter from 30 to 100 microm. We observed emergence of optimality by means of intussusception, i.e., formation of transvascular tissue pillars. In addition to intussusceptive microvascular growth (IMG = expansion of capillary networks) and intussusceptive arborization (IAR = formation of feeding vessels from capillaries) the observed intussusception at bifurcations represents a third variant of nonsprouting angiogenesis. We call it intussusceptive branching remodeling (IBR). IBR occurred in vessels of considerable diameter by means of two alternative mechanisms: either through pillars arising close to a bifurcation, which increased in girth until they merged with the connective tissue in the bifurcation angle; or through pillars arising at some distance from the bifurcation point, which then expanded by formation of ingrowing tissue folds until they became connected to the tissue of the bifurcation angle. Morphologic evidence suggests that IBR is a wide-spread phenomenon, taking place also in lung, intestinal, kidney, eye, etc., vasculature. Irrespective of the mode followed, IBR led to a branching pattern close to the predicted optimum, delta = 3.0. Significant differences were observed between delta at arterial bifurcations (2.70 to 2.90) and delta at venous bifurcations (2.93 to 3.75). IBR, by means of eccentric pillar formation and fusion, was also involved in vascular pruning. Experimental changes in CAM hemodynamics (by locally increasing blood flow) induced onset of IBR within less than 1 hr. Our study provides morphologic and quantitative evidence that a similar cellular machinery is used for all three variants of vascular intussusception, IMG, IAR, and IBR. It thus provides a mechanism of efficiently generating complex blood transport systems from limited genetic information. Differential quantitative outcome of IBR in arteries and veins, and the experimental induction of IBR strongly suggest that hemodynamic factors can instruct embryonic vascular remodeling toward optimality.     

Infantile Digital Fibroma Treated With Mohs Micrographic Surgery

BACKGROUND: Infantile digital fibroma (IDF) is a rare benign fibrous tumor of childhood that frequently recurs despite local excision. Conservative, nonsurgical management may result in regression and/or joint deformity. OBJECTIVE: To describe the histologic features of IDF and discuss a case excised using Mohs micrographic surgery (MMS). METHODS: Case report and review of the clinical, histologic, and ultrastructural features. RESULTS: Characteristic inclusion bodies of actin were identified with hematoxylin and eosin, Masson's trichrome, and rapid actin immunostain. The tumor was debulked and the majority was removed after one stage of MMS, except where the deep margin approached the joint space. The defect healed by secondary intention. At 2 years the patient had no recurrence or functional joint deformity. CONCLUSION: MMS is a surgical treatment option for IDF.     

Halswirbelsäule und Halsgefäße

The cumulative frequency of diminished stability of the major cervical arteries may be estimated between 10 and 25% in the general population. About 6% may be attributable directly to variations of the carotid arteries, and about 10% indirectly to alterations of the cervical spine, especially the atlas. Other developmental disturbances may also play a role.     

Smoking and coffee intake following alcohol withdrawal in alcoholic inpatients

The aim of this study was to assess alcoholic inpatients' smoking and coffee intake variation following withdrawal. Only moderate smokers (less than 30 cigarettes/day) showed a significant increase of cigarette consumption after alcohol withdrawal. However, their urinary cotinine level did not vary, suggesting a behavioral, and not biological, compensation through smoking following alcohol withdrawal. Heavy smokers (30 cigarettes/day or more) showed no significant clinical or biological variation of smoking behavior. Coffee consumption increased after alcohol withdrawal in all patients, irrespective of smoking habits.     

Carrier-mediated transport in the hepatic distribution and elimination of drugs, with special reference to the category of organic cations

Carrier-mediated transport of drugs occurs in various tissues in the body and may largely affect the rate of distribution and elimination. Saturable translocation mechanisms allowing competitive interactions have been identified in the kidneys (tubular secretion), mucosal cells in the gut (intestinal absorption and secretion), choroid plexus (removal of drug from the cerebrospinal fluid), and liver (hepatobiliary excretion). Drugs with quaternary and tertiary amine groups represent the large category of organic cations that can be transported via such mechanisms. The hepatic and to a lesser extent the intestinal cation carrier systems preferentially recognize relatively large molecular weight amphipathic compounds. In the case of multivalent cationic drugs, efficient transport only occurs if large hydrophobic ring structures provide a sufficient lipophilicity-hydrophilicity balance within the drug molecule. At least two separate carrier systems for hepatic uptake of organic cations have been identified through kinetic and photoaffinity labeling studies. In addition absorptive endocytosis may play a role that along with proton-antiport systems and membrane potential driven transport may lead to intracellular sequestration in lysosomes and mitochondria. Concentration gradients of inorganic ions may represent the driving forces for hepatic uptake and biliary excretion of drugs. Recent studies that aim to the identification of potential membrane carrier proteins indicate multiple carriers for organic anions, cations, and uncharged compounds with molecular weights around 50,000 Da. They may represent a family of closely related proteins exhibiting overlapping substrate specificity or, alternatively, an aspecific transport system that mediates translocation of various forms of drugs coupled with inorganic ions. Consequently, extensive pharmacokinetic interactions can be anticipated at the level of uptake and secretion of drugs regardless of their charge.     

Overexpression/amplification of HER-2/neu is uncommon in hepatocellular carcinoma

BACKGROUND： Hepatocellular carcinoma （HCC） is one of the most prevalent fatal cancers in the world. Despite advances in early diagnosis and improvements in surgical techniques, the survival of patients with HCC even after resection is poor because of the high incidence of recurrences. Therefore, the identification of prognostic factors may be helpful in the development of new treatment protocols. AIMS： To investigate HER-2/neu status in HCC by immunohistochemistry （IHC） and fluorescence in situ hybridisation （FISH）, and to explore the possibility of using trastuzumab in the treatment of HCC. METH ODS： Eight hundred and sixty eight surgical samples from patients with primary HCC were examined for their HER-2/neu status. IHC for HER-2/neu was performed with the HercepTest kit; FISH analysis was performed with the PathVysion HER-2 DNA probe kit. The correlations between HER-2/neu overexpression and clinicopathological characteristics were analysed statistically. RESULTS： HER-2/neu overexpression was detected in 21 （2.42%） of the 868 primary HCCs. Only one specimen showed HER-2/neu gene amplification by FISH. No significant associations were found between HER-2/neu overexpression and the clinicopathological parameters. CONCLUSIONS： There is a low frequency of HER-2/neu overexpression/amplification in HCC. There appears to be no role for HER-2/neu as a prognostic marker and no benefit of anti-HER-2/neu trastuzumab treatment in patients with HCC.