Changes in stiffness and biochemical composition of the pericellular matrix as a function of spatial chondrocyte organisation in osteoarthritic cartilage.

OBJECTIVE: During osteoarthritis (OA), chondrocytes seem to change their spatial arrangement from single to double strings, small and big clusters. Since the pericellular matrix (PCM) appears to degrade alongside this reorganisation, it has been suggested that spatial patterns act as an image-based biomarker for OA. The aim of this study was to establish the functional relevance of spatial organisation in articular cartilage. METHOD: Cartilage samples were selected according to their predominant spatial cellular pattern. Young's modulus of their PCM was measured by atomic force microscopy (AFM) (∼500 measurements/pattern). The distribution of two major PCM components (collagen type VI and perlecan) was analysed by immunohistochemistry (8 patients) and protein content quantified by enzyme-linked immunosorbent assay (ELISA) (58 patients). RESULTS: PCM stiffness significantly decreased with the development from single to double strings (p = 0.030), from double strings to small clusters (p = 0.015), and from small clusters to big clusters (p < 0.001). At the same time, the initially compact collagen type VI and perlecan staining progressively weakened and was less focalised. The earliest point with a significant reduction in protein content as shown by ELISA was the transition from single strings to small clusters for collagen type VI (p = 0.016) and from double strings to small clusters for perlecan (p = 0.008), with the lowest amounts for both proteins seen in big clusters. CONCLUSIONS: This study demonstrates the functional relevance of spatial chondrocyte organisation as an image-based biomarker. At the transition from single to double strings PCM stiffness decreases, followed by protein degradation from double strings to small clusters.

[Referral to rehabilitation services of patients discharged from a general hospital with a potentially disabling condition]. / Características de la población y las atenciones de rehabilitación que recibe en un hospital general.

Background Patients discharged from general hospitals with a potentially disabling condition can benefit in their recovery with the aid of physical medicine and rehabilitation services. Aim To determine the proportion of patients discharged from a general hospital with a potentially disabling condition, who were derived to physiatry for rehabilitation. Material and Methods Review of the discharge database of a general hospital, identifying all discharges with a potentially disabling condition, and those who were effectively derived for rehabilitation. Results Only 7% of patients with a potentially disabling condition were effectively evaluated by Physiatry. Among these patients, 20% had neurological diseases and 19% had an amputation. Those attended by physiatry had a higher proportion of multidisciplinary care by the rehabilitation team. Conclusions A low proportion of patients discharged with a potentially disabling conditions are referred for an adequate rehabilitation therapy.

Serial surveillance of carcinoid heart disease: factors associated with echocardiographic progression and mortality.

BACKGROUND: Carcinoid heart disease is a complication of metastatic neuroendocrine tumours (NETs). We sought to identify factors associated with echocardiographic progression of carcinoid heart disease and death in patients with metastatic NETs. METHODS: Patients with advanced non-pancreatic NETs and documented liver metastases and/or carcinoid syndrome underwent prospective serial clinical, biochemical, echocardiographic and radiological assessment. Patients were categorised as carcinoid heart disease progressors, non-progressors or deceased. Multinomial regression was used to assess the univariate association between variables and carcinoid heart disease progression. RESULTS: One hundred and thirty-seven patients were included. Thirteen patients (9%) were progressors, 95 (69%) non-progressors and 29 (21%) patients deceased. Baseline median levels of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and plasma 5-hydroxyindoleacetic acid (5-HIAA) were significantly higher in the progressors. Every 100 nmol l(-1) increase in 5-HIAA yielded a 5% greater odds of disease progression (OR 1.05, 95% CI: 1.01, 1.09; P=0.012) and a 7% greater odds of death (OR 1.07, 95% CI: 1.03, 1.10; P=0.001). A 100 ng l(-1) increase in NT-proBNP did not increase the risk of progression, but did increase the risk of death by 11%. CONCLUSIONS: The biochemical burden of disease, in particular baseline plasma 5-HIAA concentration, is independently associated with carcinoid heart disease progression and death. Clinical and radiological factors are less useful prognostic indicators of carcinoid heart disease progression and/or death.

Complement C3c as a biomarker in heart failure.

INTRODUCTION: Experimental data indicates an important role of the innate immune system in cardiac remodeling and heart failure (HF). Complement is a central effector pathway of the innate immune system. Animals lacking parts of the complement system are protected from adverse remodeling. Based on these data, we hypothesized that peripheral complement levels could be a good marker for adverse remodeling and prognosis in patients with HF. METHODS AND RESULTS: Since complement activation converges on the complement factor C3, we measured serum C3c, a stable C3-conversion product, in 197 patients with stable systolic HF. Subgroups with normal and elevated C3c levels were compared. C3c levels were elevated in 17% of the cohort. Patients with elevated C3c levels exhibited a trend to better survival, slightly higher LVEF, and lower NTpro-BNP values in comparison to patients with normal C3c values. No differences were found regarding NYHA functional class. Significantly more patients with elevated C3c had preexisting diabetes. The prevalence of CAD, arterial hypertension, and atrial fibrillation was not increased in patients with elevated C3c. CONCLUSION: Elevated C3c levels are associated with less adverse remodeling and improved survival in patients with stable systolic heart failure.

Spontaneous dissection of the LAD mimicking inferior myocardial infarction.

The case presented here is intended to raise awareness of two uncommon coronary angiographic findings in the clinical context of acute coronary syndrome. The prevalence of patients presenting with spontaneous coronary dissection as the underlying cause of an ST-elevation myocardial infarction is low. It is typically found in women, often occurring during the peripartum period. There is some debate as to whether spontaneous dissection could also be managed conservatively without coronary intervention. As for spontaneous dissection, knowledge of a culprit lesion within the distal left anterior descending artery (LAD) causing inferior ST elevation (wrap around of the LAD) is not prevalent. Patient characteristics and treatment options are discussed on the basis of the recent literature on both clinical entities.

Effects of latex avoidance on latex sensitization, atopy and allergic diseases in patients with spina bifida.

BACKGROUND: Ten years ago, avoidance measures such as the performance of latex-free operations were implemented in children with spina bifida. Since then, latex sensitization and latex allergy have decreased in this high-risk group. OBJECTIVE: To study the effect of primary latex-free prophylaxis on the prevalence of allergic diseases and atopy as a marker for sensitization spreading in children with spina bifida. METHODS: One hundred and twenty children with spina bifida born after the introduction of latex-free prophylaxis and operated on under latex-free conditions ('current group') were examined for latex sensitization, latex allergy, sensitization to aero- and food allergens and allergic diseases. Results were compared to a 'historic' (not latex-free operated) group of children with spina bifida and comparable age (n = 87) and to a recent sample of children from the general population (n = 12,403). RESULTS: In comparison with the 'historic group', latex sensitization (55% vs 5%, P < 0.001) and latex allergy (37% vs 0.8%, P < 0.001) were significantly reduced in the 'current group'. Furthermore, a significant reduction could be demonstrated for sensitization to aeroallergens (41.4% vs 20.8%, P = 0.001) and for allergic diseases (35% vs 15%, P = 0.001). The prevalence for atopy, sensitization to aero-/foodallergens and for allergic diseases in children of the 'current group' was similar to those in children of the weighted population sample. CONCLUSIONS: Latex avoidance in children with spina bifida prevents latex sensitization and latex allergy. Additionally, it also seems to prevent sensitization to other allergens and allergic diseases which might be explained by the prevention of sensitization spreading.

[Automatic detection of perfusion deficits with Bolus Harmonic Imaging]. / Bolus Harmonic Imaging zur automatischenErkennung ischämiebedingter Perfusionsdefiziteim Gehirn.

PURPOSE: The diagnosis of ischemic stroke relies increasingly on the usage of ultrasound-based methods. One of the recent methods is the transcranial, contrast agent-based Bolus Harmonic Imaging (BHI) method. The captured image sequence is manually examined by clinical experts thus resulting in a time-consuming procedure. The purpose of this study is to evaluate three different methods to analyze BHI image sequences automatically for the detection of ischemic brain tissue. MATERIALS AND METHOD: BHI captures an image sequence that provides information on the dynamic behavior of the ultrasound contrast agents. This image sequence is analyzed using three different procedures. First a system relying on expert knowledge is used to determine perfusion defects. This procedure requires parametric images, which are previously extracted from the image sequence. The parameter images are then categorized by an unsupervised classification method in well-perfused and ischemic tissue by regarding the parametric images as features describing the perfusion. Thirdly, the whole image sequence can be interpreted as a pixel-by-pixel behavior out of contrast agents. The dynamic curve of each pixel can be automatically classified as perfused and ischemic tissue by the K-Means method without extracting parametric images. In all three cases a closing step is necessary for the accurate interpretation of the results. Transcranial ultrasound imaging produces typical stripe artifacts that have to be detected and eliminated. A result image is then created and provides a conclusion about perfusion reduction in brain tissue. RESULTS: All three methods have been validated on the basis of 26 patients by clinical experts. The segmentation on the contrast agent kinetics has proven to be most effective. According to our patient database, it provides the highest detection accuracy, resulting in a sensitivity of 100% and a specificity of 100%. CONCLUSION: The presented methods seem to be adequate for detecting ischemic brain tissue. The classification of contrast agent kinetics provides the best results and has further advantages. It is robust with respect to noise and the calculation is fast because the extraction of parametric images is omitted. The very high sensitivity and specificity must be validated in a larger patient population. Reliable and automated detection of perfusion defects at the bedside seems to be possible.

Electrical high frequency stimulation of the caudate nucleus induces local GABA outflow in freely moving rats.

Electrical high frequency stimulation of the globus pallidus internus or the subthalamic nucleus has beneficial motor effects in advanced Parkinson's disease. The mechanisms underlying these clinical results remain, however, unclear. From previous in vitro studies it is proposed that the gamma-aminobutyric acid (GABA) system is involved in the effectiveness of electrical high frequency stimulation (HFS). In these experiments, we developed an in vivo model that allows for simultaneous and collocated microdialysis and HFS by electrical pulses of 124 Hz in the caudate nucleus of freely moving rats. GABA and glutamate outflow were sampled by microdialysis technique and quantified after pre-column o-phthaldialdehyde sulphite derivatization using HPLC with electrochemical detection. As the most outstanding result, we could demonstrate that high frequency stimulation significantly increased basal GABA outflow without affecting glutamate levels in freely moving rats.

Actively controlled release of Dexamethasone from neural microelectrodes in a chronic in vivo study.

Stable interconnection to neurons in vivo over long time-periods is critical for the success of future advanced neuroelectronic applications. The inevitable foreign body reaction towards implanted materials challenges the stability and an active intervention strategy would be desirable to treat inflammation locally. Here, we investigate whether controlled release of the anti-inflammatory drug Dexamethasone from flexible neural microelectrodes in the rat hippocampus has an impact on probe-tissue integration over 12 weeks of implantation. The drug was stored in a conducting polymer coating (PEDOT/Dex), selectively deposited on the electrode sites of neural probes, and released on weekly basis by applying a cyclic voltammetry signal in three electrode configuration in fully awake animals. Dex-functionalized probes provided stable recordings and impedance characteristics over the entire chronic study. Histological evaluation after 12 weeks of implantation revealed an overall low degree of inflammation around all flexible probes whereas electrodes exposed to active drug release protocols did have neurons closer to the electrode sites compared to controls. The combination of flexible probe technology with anti-inflammatory coatings accordingly offers a promising approach for enabling long-term stable neural interfaces.

Patient Education in a 14-month Randomised Trial Fails to Improve Adherence in Ulcerative Colitis: Influence of Demographic and Clinical Parameters on Non-adherence.

BACKGROUND AND AIM: Recent observational studies document that non-adherence to mesalamine therapy during remission is frequent. We aimed to investigate patient impact of patient education using objective assessments of adherence. METHODS: A 14-month randomised, prospective clinical trial of adherence to mesalamine was conducted in 248 patients with ulcerative colitis [UC], Colitis Activity Index [CAI] ≤ 9, receiving standard care [n = 122] versus a standardised patient education programme [n = 126]. Primary endpoint was adherence at all visits (5-aminosalicylic acid [5-ASA] urine levels). Secondary endpoints included quality of life (inflammatory bowel disease questionnaise [IBDQ]), disease activity, partial adherence, and self-assessment of adherence. RESULTS: Patient allocation was well balanced. Baseline non-adherence was high in quiescent/mildly active UC [52.4%] without difference between the groups (52.4% of patients in the education group versus 52.5% in the standard care group [p = 0.99]). No difference between the intervention group and standard care was seen in IBDQ, partial adherence, self-assessment of adherence, or therapy satisfaction at all visits. We suggest a model in which individual risks for non-adherence are driven by patients with young age, short disease duration, and low education levels. CONCLUSIONS: Non-adherence is frequent in a population with quiescent/mildly active UC. Although more than 25% of the population was not in remission at the various time points, no relationship between disease activity and adherence was seen over the 14-month observation period. Physicians should maximise their efforts to motivate high-risk patients for adherence. Future trials should use objective exposure assessments to examine the impact of continuous education and consultations on the background of individual risks to develop non-adherence.

[The pediatric surgeon's role in intensive care]. / Intensivmedizin aus Sicht des Kinderchirurgen.

In contrast to adult surgery, pediatric surgery today is particularly dependent on multidisciplinary cooperation, especially with pediatricians, neonatologists, and pediatric anesthesiologists. This is particularly important in intensive care. Pediatric surgery is not able to manage this challenge on its own because of small numbers of intensive care patients, small staff with few intensive care specialists, and little general interest. The pediatric surgeon's role in interdisciplinary intensive care is to ensure optimal treatment for his patients by helpful cooperation, commitment, and readiness to take on responsibility, together with his own irreplaceable expertise.

Versatile 3D-printed headstage implant for group housing of rodents.

BACKGROUND: An unfavourable yet necessary side-effect of stereotaxic surgery involves the social isolation of post-surgery rats, in order to protect their wound site or skull-mounted implant from damage. Social isolation can cause a myriad of behavioural and physiological changes that are detrimental to the well-being of rats, with potential negative implications for a range of experimental paradigms. New method. Female Sprague Dawley rats (n=40) were implanted onto the skull with a novel 3D-printed headstage socket that surrounded an electrode connector. The socket accommodated a removable stainless-steel headcap for the purposes of protecting the implant. Rats were pair-housed following surgery, and their behaviour was monitored for up to several weeks under two experimental conditions that involved EEG recording and deep-brain stimulation, as well as behavioural test sessions inside an open-field maze. Rat weights were compared between individually- and pair-housed rats at up to 3 weeks post-surgery. RESULTS: These experiments were successfully carried out using pair-housed rats, with no damage or complications observed regarding the implant and its headcap. Rats were able to carry out a range of normal behaviours including running, grooming, foraging and sleeping. Compared to individually-housed rats, pair-housed rats gained less weight over the 3 weeks post-implantation period. Comparison with existing method(s). This method offers additional protection compared to group-housed post-surgical rats that lack the protective headcap. It is also potentially more practical and versatile than a fully-implantable device for the safe post-surgery group housing of rodents. CONCLUSIONS: This implant design can reduce the cost of rodent upkeep, whilst potentially avoiding a myriad of behavioural and physiological changes that are known to result from social isolation.

Heritability of Caffeine Metabolism: Environmental Effects Masking Genetic Effects on CYP1A2 Activity but Not on NAT2.

Heritability of caffeine pharmacokinetics and cytochrome P450 1A2 (CYP1A2) activity is controversial. Here, we analyzed the pharmacokinetics of caffeine, an in vivo probe drug for CYP1A2 and arylamine N-acetyltransferase 2 (NAT2) activity, in monozygotic (MZ) and dizygotic (DZ) twins. In the entire group, common and unique environmental effects explained most variation in caffeine area under the curve (AUC). Apparently, smoking and hormonal contraceptives masked the genetic effects on CYP1A2 activity. However, when excluding smokers and users of hormonal contraceptives, 89% of caffeine AUC variation was due to genetic effects and, even in the entire group, 8% of caffeine AUC variation could be explained by a CYP1A1/1A2 promotor polymorphism (rs2470893). In contrast, nearly all of the variations (99%) of NAT2 activity were explained by genetic effects. This study illustrates two very different situations in pharmacogenetics from an almost exclusively genetic determination of NAT2 activity with no environmental modulation to only moderate genetic effects on CYP1A2 activity with strong environmental modulation.

Heritability of metoprolol and torsemide pharmacokinetics.

Genetic variation in the pharmacokinetics of metoprolol and torsemide due to polymorphisms in CYP2D6, CYP2C9, and OATP1B1 has been extensively studied. However, it is still unknown how much of the variation in pharmacokinetics of these two clinically important drugs in total is due to genetic factors. Metoprolol and torsemide were intravenously administered to 44 monozygotic and 14 dizygotic twin pairs. Metoprolol area under the curve (AUC) varied 4.7-fold and torsemide AUC 3.5-fold. A very high fraction of AUC variations, 91% of metoprolol and 86% of torsemide, were found to be due to additive genetic effects. However, known genetic variants of CYP2D6, -2C9, and OATP1B1 explained only 39%, 2%, and 39% of that variation, respectively. Comparable results for genetically explained variation in pharmacokinetics and pharmacodynamics have been found for other substrates of these enzymes earlier. These findings indicate that a substantial fraction of the heritable variability in the pharmacokinetics of metoprolol and torsemide remains to be elucidated.

Matrix metalloproteinases in human melanoma.

Cutaneous melanoma is a highly invasive and metastatic tumor. Degradation of basement membranes and extracellular matrix is an essential step in melanoma cell migration, invasion, and metastasis formation. Matrix metalloproteinases and their tissue inhibitors play a crucial role in these complex multistep processes. Melanoma cells may express a number of matrix metalloproteinase family members (MMP-1, MMP-2, MMP-9, MMP-13, and MT1-MMP) as well as their tissue inhibitors (TIMP-1, TIMP-2, and TIMP-3). Numerous studies have examined matrix metalloproteinases, their tissue inhibitors, and the molecules that regulate their expression and/or activation in melanoma cell lines in vitro and in vivo, and in human melanocytic lesions. Recent results have indicated that adhesion molecules such as CD44 and integrin alphavbeta3 are involved in positioning activated matrix metalloproteinase molecules on the cell surface of invasive tumor cells. In this review we evaluate these novel aspects of the role of matrix metalloproteinases and their tissue inhibitors in melanoma progression. We conclude that the balance between levels of activated matrix metalloproteinases and expression levels of their tissue inhibitors, and the coexpression of activated matrix metalloproteinases and adhesion molecules are important factors in determining melanoma cell invasion, tumor growth, and metastasis formation.

MHC class I expression in murine skin: developmentally controlled and strikingly restricted intraepithelial expression during hair follicle morphogenesis and cycling, and response to cytokine treatment in vivo.

Hair bulb keratinocytes generate one of the few "immune privileged" tissue compartments of the mammalian organism by suppressing classical MHC class I (MHC Ia) antigens. Expression of non-classical MHC class I (MHC Ib) antigens in the follicle has been found, but only in its distal epithelium. Here, we have defined when during murine hair follicle morphogenesis these peculiar MHC Ia and Ib expression patterns are established, how they change during the murine hair cycle, and how different MHC I modulatory agents alter follicular MHC Ia and Ib expression in vivo. During neonatal hair follicle morphogenesis in C57BL/6 mice, distal follicle keratinocytes began to express MHC Ia (H2b) only late in development. The MHC Ib antigens, Qa-1 and Qa-2, did not become visible until the initiation of follicle cycling, with Qa-1 expression being more widespread than that of Qa-2. H2b, Qa-1, and TAP-1 immunoreactivity on previously negative keratinocytes of the proximal anagen hair bulb was upregulated by intradermal injection of the proinflammatory cytokine interferon-gamma, but not by tumor necrosis factor-alpha or interleukin-1beta. Injection of the reportedly MHC class I downregulating agents interleukin-10, insulin-like growth factor-1, transforming growth factor-beta, alpha-melanocyte stimulating hormone, or dexamethasone, however, all failed to downregulate constitutive or interferon-gamma-induced follicular MHC Ia expression. This shows that the hair follicle is a previously unrecognized site of Qa-1 expression and that interferon-gamma is a key regulator of follicular MHC I expression in vivo. It also suggests that the developmental and immunologic controls of MHC I expression by follicle keratinocytes differ from those of other epithelial cells.

Coexpression of integrin alpha(v)beta3 and matrix metalloproteinase-2 (MMP-2) coincides with MMP-2 activation: correlation with melanoma progression.

Tumor cell invasion and metastasis formation depend on both adhesive and proteolytic mechanisms. Previous studies have shown that expression of matrix metalloproteinase-2 and integrin alphavbeta3 correlate with melanoma progression. Recently, direct binding of matrix metalloproteinase-2 to alpha(v)beta3 was implicated in presenting activated matrix metalloproteinase-2 on the cell surface of invasive cells. In this study we investigated this, using the highly metastatic, alpha(v)beta3-negative melanoma cell lines MV3 and BLM, their beta3-transfected alpha(v)beta3 expressing counterparts, xenografts derived from these cell lines, and fresh human cutaneous melanoma lesions comprising all stages of melanoma progression. Expression and activation status of matrix metalloproteinase-2 were studied by reverse transcription-polymerase chain reaction, immunohistochemistry, western blotting, and zymographic analysis, respectively. Matrix metalloproteinase-2 protein expression in vitro was similar in both alpha(v)beta3-negative and alpha(v)beta3-positive cell lines Remarkable differences, however, exist in the localization of inactive and active matrix metalloproteinase-2. Soluble active matrix metalloproteinase-2 was detectable only in the conditioned medium of alpha(v)beta3-negative cell lines and undetectable in the alpha(v)beta3-positive cell lines. Conversely, active matrix metalloproteinase-2 was present exclusively on the cell surface of the alpha(v)beta3 expressing transfectants. Western blot analysis of other components that are involved in matrix metalloproteinase-2 activation showed that processing of proMT1-matrix metalloproteinase to the activated form was enhanced in beta3 transfectants, whereas secretion of tissue inhibitor of metalloproteinase-2 was decreased. In vivo, the presence of functionally active matrix metalloproteinase-2 was significantly higher in xenografts derived from the alpha(v)beta3 expressing MV3 and BLM cell lines. In human cutaneous melanoma lesions, neither matrix metalloproteinase-2 nor integrin alpha(v)beta3 is detectable in melanoma in situ as determined by immunohistochemistry. In contrast, the number of matrix metalloproteinase-2-positive and alphavbeta3-positive tumor cells was clearly increased in primary melanomas, and melanoma metastases. Double staining experiments and confocal laser microscopy demonstrated that the percentage of cells coexpressing matrix metalloproteinase-2 and alpha(v)beta3 increased in advanced primary melanomas and melanoma metastases. In addition, zymography showed that functionally active matrix metalloproteinase-2 was frequently present in melanoma metastases. In these lesions a high proportion of matrix metalloproteinase-2- and alphavbeta3-double-positive melanoma cells were detectable. Our study demonstrates that the presence of activated matrix metalloproteinase-2 correlates with expression of alpha(v)beta3 in human melanoma cells both in vitro and in vivo, and also in fresh human melanoma lesions. These findings strongly suggest that co-ordinated expression of both factors may be required for melanoma cell invasion and metastasis formation.

A comprehensive guide for the recognition and classification of distinct stages of hair follicle morphogenesis.

Numerous spontaneous and experimentally induced mouse mutations develop a hair phenotype, which is often associated with more or less discrete abnormalities in hair follicle development. In order to recognize these, it is critically important to be able to determine and to classify accurately the major stages of normal murine hair follicle morphogenesis. As an aid, we propose a pragmatic and comprehensive guide, modified after previous suggestions by Hardy, and provide a list of easily recognizable classification criteria, illustrated by representative micrographs. Basic and more advanced criteria are distinguished, the former being applicable to all mouse strains and requiring only simple histologic stains (hematoxylin and eosin, Giemsa, periodic acid Schiff, alkaline phosphatase activity), the latter serving as auxiliary criteria, which require a pigmented mouse strain (like C57BL/6J) or immunohistochemistry (interleukin-1 receptor type I, transforming growth factor-beta receptor type II). In addition, we present simplified, computer-generated schematic drawings for the standardized recording and reporting of gene and antigen expression patterns during hair follicle development. This classification aid serves as a basic introduction into the field of hair follicle morphogenesis, aims at standardizing the presentation of related hair research data, and should become a useful tool when screening new mouse mutants for discrete abnormalities of hair follicle morphogenesis (compared with the respective wild type) in a highly reproducible, easily applicable, and quantifiable manner.

Generation and cyclic remodeling of the hair follicle immune system in mice.

In this immunohistomorphometric study, we have defined basic characteristics of the hair follicle (HF) immune system during follicle morphogenesis and cycling in C57BL/6 mice, in relation to the skin immune system. Langerhans cells and gammadelta T cell receptor immunoreactive lymphocytes were the predominant intraepithelial hematopoietic cells in neonatal mouse skin. After their numeric increase in the epidermis, these cells migrated into the HF, although only when follicle morphogenesis was almost completed. In contrast to Langerhans cells, gammadelta T cell receptor immunoreactive lymphocytes entered the HF only via the epidermis. Throughout HF morphogenesis and cycling, both cell types remained strikingly restricted to the distal outer root sheath. On extremely rare occasions, CD4+ or CD8+ alphabetaTC were detected within the HF epithelium or the sebaceous gland. Major histocompatibility complex class II+, MAC-1+ cells of macrophage phenotype and numerous mast cells appeared very early on during HF development in the perifollicular dermis, and the percentage of degranulated mast cells significantly increased during the initiation of synchronized HF cycling (first catagen). During both depilation- and cyclosporine A-induced HF cycling, the numbers of intrafollicular Langerhans cells, gammadelta T cell receptor immunoreactive lymphocytes, and perifollicular dermal macrophages fluctuated significantly. Yet, no numeric increase of perifollicular macrophages was detectable during HF regression, questioning their proposed role in catagen induction. In summary, the HF immune system is generated fairly late during follicle development, shows striking differences to the extrafollicular skin immune system, and undergoes substantial hair cycle-associated remodeling. In addition, synchronized HF cycling is accompanied by profound alterations of the skin immune system.

Consequences of rifampicin treatment on propafenone disposition in extensive and poor metabolizers of CYP2D6.

Propafenone undergoes extensive metabolism both by phase I and phase II enzymes: cytochrome P4502D6 (CYP2D6) dependent polymorphic hydroxylation to its main metabolite 5-OH-propafenone, CYP3A4/1A2 dependent N-dealkylation and further glucuronidation and sulfation. Since CYP2D6 is not inducible by rifampicin, an important drug interaction between rifampicin and propafenone is not to be expected a priori. However, non-CYP2D6-dependent pathways may be induced as a case report described dramatically lowered plasma concentrations of propafenone with loss of dysrhythmia control associated with rifampicin treatment. Therefore, this study aimed to investigate induction properties of rifampicin on propafenone disposition in extensive metabolizers and poor metabolizers of CYP2D6. Six extensive metabolizers and six poor metabolizers ingested 600 mg rifampicin once daily for nine consecutive days. The day before the first rifampicin dose and on the day of the last rifampicin dose each individual received a single intravenous (i.v.) infusion of 140 mg unlabelled propafenone and 2 h later a single dose of 300 mg deuterated propafenone orally (p.o.). During enzyme induction maximum QRS prolongation decreased significantly after propafenone p.o. (21 +/- 7% versus 13 +/- 6% in extensive metabolizers, P < 0.01; 15 +/- 6% versus 9 +/- 6% in poor metabolizers, P < 0.01) and not after propafenone i.v. In parallel, there were no substantial differences in pharmacokinetics of propafenone i.v. by rifampicin. However, bioavailability of propafenone dropped from 30 +/- 15% to 10 +/- 8% in extensive metabolizers (P < 0.01) and from 81 +/- 6% to 48 +/- 8% in poor metabolizers (P < 0.001). Following propafenone p.o. clearances through N-dealkylation (4.1 +/- 2.1 ml/min versus 23.5 +/- 12.6 ml/min in extensive metabolizers, P < 0.01; 3.4 +/- 1.3 ml/min versus 16.0 +/- 5.5 ml/min in poor metabolizers, P < 0.001) and glucuronidation (123 +/- 48 ml/min versus 457 +/- 267 ml/min in extensive metabolizers, P < 0.05; 43 +/- 9 ml/min versus 112 +/- 34 ml/min in poor metabolizers, P < 0.01), but not 5-hydroxylation increased regardless of phenotype indicating substantial enzyme induction. Clearances to propafenone sulfate and conjugates of 5-OH-propafenone were significantly enhanced by rifampicin treatment in poor metabolizers (P < 0.01). Thus, induction of both phase I pathways (CYP3A4/1A2) and phase II pathways (glucuronidation, sulfation) of propafenone by rifampicin resulted in a clinically relevant metabolic drug interaction which was more pronounced in extensive metabolizers than in poor metabolizers with regard to percentage decrease in bioavailability of propafenone.