Clinical adoptive regulatory T Cell therapy: State of the art, challenges, and prospective

Rejection of solid organ transplant and graft versus host disease (GvHD) continue to be challenging in post transplantation management. The introduction of calcineurin inhibitors dramatically improved recipients' short-term prognosis. However, long-term clinical outlook remains poor, moreover, the lifelong dependency on these toxic drugs leads to chronic deterioration of graft function, in particular the renal function, infections and de-novo malignancies. These observations led investigators to identify alternative therapeutic options to promote long-term graft survival, which could be used concomitantly, but preferably, replace pharmacologic immunosuppression as standard of care. Adoptive T cell (ATC) therapy has evolved as one of the most promising approaches in regenerative medicine in the recent years. A range of cell types with disparate immunoregulatory and regenerative properties are actively being investigated as potential therapeutic agents for specific transplant rejection, autoimmunity or injury-related indications. A significant body of data from preclinical models pointed to efficacy of cellular therapies. Significantly, early clinical trial observations have confirmed safety and tolerability, and yielded promising data in support of efficacy of the cellular therapeutics. The first class of these therapeutic agents commonly referred to as advanced therapy medicinal products have been approved and are now available for clinical use. Specifically, clinical trials have supported the utility of CD4⁺CD25+FOXP3+ regulatory T cells (Tregs) to minimize unwanted or overshooting immune responses and reduce the level of pharmacological immunosuppression in transplant recipients. Tregs are recognized as the principal orchestrators of maintaining peripheral tolerance, thereby blocking excessive immune responses and prevent autoimmunity. Here, we summarize rationale for the adoptive Treg therapy, challenges in manufacturing and clinical experiences with this novel living drug and outline future perspectives of its use in transplantation.

Advanced Therapy Medicinal Products' Translation in Europe: A Developers' Perspective

Advanced Therapy Medicinal Products (ATMPs) comprising cell, gene, and tissue-engineered therapies have demonstrated enormous therapeutic benefits. However, their development is complex to be managed efficiently within currently existing regulatory frameworks. Legislation and regulation requirements for ATMPs must strike a balance between the patient safety while promoting innovations to optimize exploitation of these novel therapeutics. This paradox highlights the importance of on-going dynamic dialogue between all stakeholders and regulatory science to facilitate the development of pragmatic ATMP regulatory guidelines.

Longitudinal stability of molecular alterations and drug response profiles in tumor spheroid cell lines enables reproducible analyses

The utility of patient-derived tumor cell lines as experimental models for glioblastoma has been challenged by limited representation of the in vivo tumor biology and low clinical translatability. Here, we report on longitudinal epigenetic and transcriptional profiling of seven glioblastoma spheroid cell line models cultured over an extended period. Molecular profiles were associated with drug response data obtained for 231 clinically used drugs. We show that the glioblastoma spheroid models remained molecularly stable and displayed reproducible drug responses over prolonged culture times of 30 in vitro passages. Integration of gene expression and drug response data identified predictive gene signatures linked to sensitivity to specific drugs, indicating the potential of gene expression-based prediction of glioblastoma therapy response. Our data thus empowers glioblastoma spheroid disease modeling as a useful preclinical assay that may uncover novel therapeutic vulnerabilities and associated molecular alterations.

Immunogenicity of CAR T cells in cancer therapy

Patient-derived T cells genetically reprogrammed to express CD19-specific chimeric antigen receptors (CARs) have shown remarkable clinical responses and are commercially available for the treatment of patients with certain advanced-stage B cell malignancies. Nonetheless, several trials have revealed pre-existing and/or treatment-induced immune responses to the mouse-derived single-chain variable fragments included in these constructs. These responses might have contributed to both treatment failure and the limited success of redosing strategies observed in some patients. Data from early phase clinical trials suggest that CAR T cells are also associated with immunogenicity-related events in patients with solid tumours. Generally, the clinical implications of anti-CAR immune responses are poorly understood and highly variable between different CAR constructs and malignancies. These observations highlight an urgent need to uncover the mechanisms of immunogenicity in patients receiving CAR T cells and develop validated assays to enable clinical detection. In this Review, we describe the current clinical evidence of anti-CAR immune responses and discuss how new CAR T cell technologies might impact the risk of immunogenicity. We then suggest ways to reduce the risks of anti-CAR immune responses to CAR T cell products that are advancing towards the clinic. Finally, we summarize measures that investigators could consider in order to systematically monitor and better comprehend the possible effects of immunogenicity during trials involving CAR T cells as well as in routine clinical practice.

Microphysiological systems meet hiPSC technology - New tools for disease modeling of liver infections in basic research and drug development

Complex cell culture models such as microphysiological models (MPS) mimicking human liver functionality in vitro are in the spotlight as alternative to conventional cell culture and animal models. Promising techniques like microfluidic cell culture or micropatterning by 3D bioprinting are gaining increasing importance for the development of MPS to address the needs for more predictivity and cost efficiency. In this context, human induced pluripotent stem cells (hiPSCs) offer new perspectives for the development of advanced liver-on-chip systems by recreating an in vivo like microenvironment that supports the reliable differentiation of hiPSCs to hepatocyte-like cells (HLC). In this review we will summarize current protocols of HLC generation and highlight recently established MPS suitable to resemble physiological hepatocyte function in vitro. In addition, we are discussing potential applications of liver MPS for disease modeling related to systemic or direct liver infections and the use of MPS in testing of new drug candidates.

Comprehensive human stem cell differentiation in a 2D and 3D mode to cardiomyocytes for long-term cultivation and multiparametric monitoring on a multimodal microelectrode array setup

Human pluripotent stem cell derived cardiomyocytes are a promising cell source for research and clinical applications like investigation of cardiomyopathies and therefore, identification and testing of novel therapeutics as well as for cell based therapy approaches. However, actually it´s a challenge to generate matured adult cardiomyocyte-like phenotype in a reasonable time. Moreover, there is a lack of applicable non-invasive label-free monitoring techniques providing quantitative parameters for analysing the culture stability and maturation status. In this context, we established an efficient protocol based on a combined differentiation of hiPSC in 2D cultures followed by a forced reaggregation step that leads to highly enriched (>90% cardiomyocytes) cardiomyocyte clusters. Interestingly, 3D cultures revealed an accelerated maturation as well as phenotype switch from atrial to ventricular cardiomyocytes. More strikingly using combined impedimetric and electrophysiological monitoring the high functionality and long-term stability of 3D cardiomyocyte cultures, especially in comparison to 2D cultures could be demonstrated. Additionally, chronotropic as well as QT-prolongation causing reference compounds were used for validating the cardio specific and sensitive reaction over the monitored time range of more than 100 days. Thus, the approach of multiparametric bioelectronic monitoring offers capabilities for the long-term quantitative analysis of hiPS derived cardiomyocyte culture functionality and long-term stability. Moreover, the same multiparametric bioelectronic platform can be used in combination with validated long-term stable cardiomyocyte cultures for the quantitative detection of compound induced effects. This could pave the way for more predictive in vitro chronic/repeated dose cardiotoxicity testing assays.

[Treatment of an osteo-fascio-cutaneous defect of the femur with a serial connected flow-through free-flap]

Covering large osteo-fascio-cutaneous defects after debridement often calls for elaborate soft tissue reconstruction. Large tissue loss or structural damage that requires distinct repair is rarely coverable by a single conventional flap. Here, we report the case of serial flap coverage using sequentially connected fibular and latissimus dorsi free flaps.

The nuclear aryl hydocarbon receptor is involved in regulation of DNA repair and cell survival following treatment with ionizing radiation

In the present study, we explored the role of the aryl hydrocarbon receptor (AhR) for γ-H2AX associated DNA repair in response to treatment with ionizing radiation. Ionizing radiation was able to stabilize AhR protein and to induce a nuclear translocation in a similar way as described for exposure to aromatic hydrocarbons. A comparable AhR protein stabilization was obtained by treatment with hydroxyl-nonenal-generated by radiation-induced lipid peroxidation. AhR knockdown resulted in significant radio-sensitization of both A549- and HaCaT cells. Under these conditions an increased amount of residual γ-H2AX foci and a delayed decline of γ-H2AX foci was observed. Knockdown of the co-activator ARNT, which is essential for transcriptional activation of AhR target genes, reduced AhR-dependent CYP1A expression in response to irradiation, but was without effect on the amount of residual γ-H2AX foci. Nuclear AhR was found in complex with γ-H2AX, DNA-PK, ATM and Lamin A. AhR and γ-H2AX form together nuclear foci, which disappear during DNA repair. Presence of nuclear AhR protein is associated with ATM activation and chromatin relaxation indicated by acetylation of histone H3. Taken together, we could show, that beyond the function as a transcription factor the nuclear AhR is involved in the regulation of DNA repair. Reduction of nuclear AhR inhibits DNA-double stand repair and radiosensitizes cells. First hints for its molecular mechanism suggest a role during ATM activation and chromatin relaxation, both essential for DNA repair.

[An immobilising malignant phyllodes tumour of the breast]

Phyllodes tumours of the breast are rare occurrences, but they can reach huge dimensions. Descriptions of tumours whereby the women are immobilised as a consequence of the size of the tumour, are hard to find in the literature. In this presentation we show a case of a woman in otherwise healthy condition with a giant phyllodes tumour of her left breast. Because of the weight of the tumour, the patient could not leave her bed for more than 6 months.

[Long-term outcome after surgical treatment of breast asymmetry: analysis of the patient's perspective in 51 cases]

INTRODUCTION

Literature provides 3 studies only investigating the long-term outcome after surgical correction of breast asymmetry. The goal of this study was to analyse from a patient's perspective, which factors influence postoperative satisfaction most.

PATIENTS AND METHODS

All patients undergoing surgical treatment for breast asymmetry between 2000 and 2009 were included. With help of the visual analogue scale the patients conducted a subjective assessment of their own long-term result using the following parameters: overall satisfaction, symmetry, size, shape, scarring and sensitivity. Anthropometric measurements of the breasts followed.

RESULTS

51 patients (80% follow-up) were seen 2-11 (mean 5±2.5) years postoperatively. The following mean values were recorded for overall satisfaction 8.31 (±1.91), symmetry 7.86 (±2.25), size 8.42 (±1.93), shape 8.12 (±2.03), scarring 7.82 (±1.94) and sensitivity 7.92 (±2.19). Overall satisfaction increased significantly with good scores for the parameters symmetry [p=0.01] and shape [p=0.048]. Neither size [p=0.46] nor scarring [p=0.69] nor sensitivity [p=0.34] had a statistically significant influence on overall satisfaction. Furthermore, overall satisfaction did not depend on the surgical technique, preoperative size, preoperative asymmetry, age of the patient at time of surgery, period of time between the operation and the assessment, resected weight (absolute and difference between left and right) or on postoperative symmetry of the nipple areola complex.

CONCLUSION

In our patients, long-term overall satisfaction after surgical correction of breast asymmetry was primarily dependent on symmetry and shape. Size, scarring and sensitivity did not have a statistically significant influence on postoperative overall satisfaction. This also applied to preoperative size, preoperative extent of asymmetry, age of the patient at time of surgery, surgical technique and the time span between the operation and the assessment.

[The interesting case: unilateral hypoplasia of the breast in Becker nevus syndrome]

The Becker nevus syndrome is defined by the association of a Becker's nevus with ipsilateral breast hypoplasia and/or musculoskeletal disorders. There are only a few dozen case reports in the literature. We here present the case of a 20-year-old female patient who was treated in our clinic due to a breast asymmetry.

Evidence for a novel anti-apoptotic pathway in human keratinocytes involving the aryl hydrocarbon receptor, E2F1, and checkpoint kinase 1

Exposure of keratinocytes (KC) to ultraviolet (UV) radiation results in the initiation of apoptosis, a protective mechanism that eliminates cells harboring irreparable DNA damage. Hence, a manipulation of UV-induced apoptosis may significantly influence photocarcinogenesis. We have discovered that the aryl hydrocarbon receptor (AHR), a key regulator of drug metabolism and an UVB-sensitive transcription factor, serves an anti-apoptotic function in UVB-irradiated human KC. Chemical and shRNA-mediated inhibition of AHR signaling sensitized KC to UVB-induced apoptosis by decreasing the expression of E2F1 and its target gene checkpoint kinase 1 (CHK1). The decreased expression of these cell-cycle regulators was due to an enhanced expression of p27(KIP1) and an associated decrease in phosphorylation of both cyclin-dependent kinase 2 and its substrate molecule retinoblastoma protein. The subsequent inhibition of E2F1 autoregulation and downstream CHK1 expression resulted in an enhanced susceptibility of damaged cells to undergo apoptosis. Accordingly, ectopic overexpression of either E2F1 or CHK1 in AHR-knockdown KC attenuated the observed sensitization to UVB-induced apoptosis. Using an AHR-knockout SKH-1 hairless mouse model, we next demonstrated the physiological relevance of the anti-apoptotic function of AHR. In contrast to their AHR-proficient littermates, the constitutive expression of E2F1 and CHK1 was significantly reduced in the skin of AHR-knockout mice. Accordingly, a single exposure of the animals to UVB resulted in an enhanced cleavage of caspase-3 in the skin of AHR-knockout mice. These results identify for the first time the AHR-E2F1-CHK1 axis as a novel anti-apoptotic pathway in KC, which may represent a suitable target for chemoprevention of non-melanoma skin cancer.

[One-stage reconstruction of facial defects after tumor resection with the Integra system]

BACKGROUND

In 2010 excellent aesthetic results after basal cell carcinoma excision and one-stage coverage with Integra without split thickness skin graft (STSG) were published in a series of 10 Asian patients. Our aim in this study was to verify these results in a series of Caucasian patients and evaluate this procedure as a possible new standard.

PATIENTS AND METHODS

6 patients with facial basal cell carcinoma were treated by regular excision with 3 mm safety margins and one-stage coverage with Integra without STSG, followed by a clinical evaluation and fotodocumentation.

RESULTS

In 3 patients local infection occurred with a complete loss of the Integra. 2 out of these 3 patients showed an unaesthetic scar and are considering another surgical approach for correction. The other 3 patients had an uneventful course, unfortunately 2 out of these patients (67%) developed an unaesthetic scar as well and are also considering surgical correction.

CONCLUSION

Because of aesthetically unsatisfactory results and high infection rates we abandoned this procedure after 6 patients only. Our standard remains excision with 3 mm safety margins, histological analysis and one-stage repair with local facial flaps.

Activation of the aryl hydrocarbon receptor sensitises human keratinocytes for CD95L- and TRAIL-induced apoptosis

In this study, we have analysed the apoptotic effects of the ubiquitous environmental toxin benzo[a]pyrene (BP) in HaCaT cells and human keratinocytes. Although prolonged exposure to BP was not cytotoxic on its own, a strong enhancement of CD95 (Fas)-mediated apoptosis was observed with BP at concentrations activating the aryl hydrocarbon receptor (AhR). Importantly, the ultimately mutagenic BP-metabolite, that is, (+)-anti-BP-7,8-diol-9,10-epoxide (BPDE), failed to enhance CD95-mediated cell death, suggesting that the observed pro-apoptotic effect of BP is neither associated with DNA adducts nor DNA-damage related signalling. CD95-induced apoptosis was also enhanced by β-naphtoflavone, a well-known agonist of the AhR that does not induce DNA damage, thus suggesting a crucial role for AhR activation. Consistently, BP failed to sensitise for CD95L-induced apoptosis in AhR knockdown HaCaT cells. Furthermore, inhibition of CYP1A1 and/or 1B1 expression did not affect the pro-apoptotic crosstalk. Exposure to BP did not increase expression of CD95, but led to augmented activation of caspase-8. Enhancement of apoptosis was also observed with the TRAIL death receptors that activate caspase-8 and apoptosis by similar mechanisms as CD95. Together, these observations indicate an interference of AhR signalling with the activity of receptor-associated signalling intermediates that are shared by CD95 and TRAIL receptors. Our data thus suggest that AhR agonists can enhance cytokine-mediated adversity upon dermal exposure.

[Sensory nerve function after unilateral digital vascular-nerve injury: nerve repair with and without arterial repair]

PURPOSE

This study compares the clinical results of microsurgical nerve repairs in unilateral digital arterial-nerve-injuries with and without repair of the finger artery.

PATIENTS AND METHODS

Between January 2000 and May 2007 a total of 81 patients with unilateral digital vascular nerve bundle lesions, including concomitant soft-tissue tendon lesions, were operated on the emergency day. Forty of the 56 patients treated with a nerve repair alone took part in a follow-up after an average of 47 (7-87) months. Twenty of the 25 patients treated with a microsurgical arterial and nerve repair took part in a follow-up after an average of 12 (6-66) months; 3 patients were excluded due to a negative digital Allen-test. In addition to anamnestic data, peripheral nerve function was evaluated by the static and the moving two-point discrimination test, and by Semmes-Weinstein pressure aesthesiometer in the autonomous zone of the affected side of the injured finger. Stereognosis also was examined. The patency of the reconstructed digital artery was tested by a digital Allen-test.

RESULTS

No statistically significantly worse results were found in patients with a nerve repair alone compared to patients with additional repair of the finger artery.

CONCLUSION

Repair of the finger artery therefore appears to offer no improvement of the clinical outcome following nerve repair in unilateral injury of a digital arterial-nerve bundle.

Internal thoracic vessels as recipient vessels for free flap reconstruction in head and neck surgery

In rare cases the usage of the internal thoracic vessels as recipient vessels in reconstructive surgery of the head and neck region with free tissue transfer is a challenging but valid alternative if local recipient vessels are unusable.

Cavernous haemangioma in the hand mimicking subacute tenosynovitis

A case of cavernous haemangioma arising from the superficial palmar arch is described. The initial symptoms were those of a subacute tenosynovitis. Surgical exploration showed that the tumor was not affecting the flexor tendons. It was completely resected and the patient had full recovery of hand function.

Mutations at the mitochondrial DNA polymerase (POLG) locus associated with male infertility

Human mitochondrial DNA polymerase, encoded by POLG, contains a polyglutamine tract encoded by a CAG microsatellite repeat. Analysis of POLG genotypes in different populations identified an association between absence of the common, ten-repeat allele and male infertility typified by a range of sperm quality defects but excluding azoospermia.

Functional characterization of cyclooxygenase-2 polymorphisms

Cyclooxygenases (COX)-1 and -2 are the key enzymes in the conversion of arachidonic acid to prostaglandins. COX-2 appears to play an emerging role in inflammation and carcinogenesis. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used for the treatment of numerous diseases and reduce the risk of developing colorectal cancer. Polymorphisms in the COX-2 gene could alter enzyme expression, function, and/or the response to NSAIDs. Therefore, they could modify individual risks for developing cancer and other diseases or the occurrence of side effects or sensitivity toward selective or nonselective COX inhibitors. We sequenced the COX-2 gene of 72 individuals and identified rare polymorphisms in the promoter and the coding region. A COX-2 molecular model was used to locate the coding region polymorphisms relative to functional sites in the protein, and the COX-2 V511A polymorphism was very near to the active site. This variant protein was expressed, and function was evaluated, but no difference was detected in metabolism of the COX-2 substrates, arachidonic acid, linoleic acid, and 2-arachidonyl glycerol, compared with the wild type. The Km values for arachidonic acid showed no differences between the COX-2 wild type and V511A mutant. Inhibition with selective or nonselective COX inhibitors was essentially the same for the two enzymes. The absence of functionally important polymorphisms in the COX-2 gene may suggest that there has been selective pressure against those single nucleotide polymorphisms because of the critical role of this enzyme in maintenance of homeostasis.

[Mallet-thumb--presentation and discussion of 3 cases of a rare lesion]

Three cases of closed extensor tendon ruptures without osseous involvement in Verdan's zone 1 of the thumb (Mallet thumb) are presented and the various treatment options discussed based on the pertinent literature. As a consequence of the special anatomy of the thumb's extensor tendons which differs from that in the fingers, we recommend surgical treatment of this rare lesion by transosseous refixation of the ruptured tendon. Thus, early postoperative motion can be initiated resulting in rapid recovery of complete function.

[Reduction of breasts ... Hans Schaller and the first mammaplasty in 1561. Contribution to history of medicine]

In comparison with other surgical procedures concerning the breast, the history of reduction mammaplasty is relatively short. Some authors have mistaken Paulos of Aegina for the pioneer in this field, although he occupied himself exclusively with gynaecomastia. Since some decades Hanns Schaller, the so-called "barber" of Augsburg, is considered to be the first surgeon to have performed a reduction mammaplasty by breast amputation in 1561. However, exact references have not been available so far. We found the original text containing the description of the procedure written by a contemporary in a rather unexpected place as well as some details about the surgeon. We conclude that Hanns Schaller was the first surgeon to undertake a reduction mammaplasty in an otherwise healthy woman in order to relieve her physical symptoms. Undoubtedly, his intentions were purely functional without any further aesthetic considerations.

Xenobiotic metabolism, genetic polymorphisms and male infertility

Male reproductive function may be impaired by various occupational and environmental chemical agents. The majority of these xenobiotics, however, require metabolic activation in order to exert adverse effects via covalent interactions between intermediate metabolites and cellular macromolecules such as DNA or protein. In addition, metabolization may alter endocrine-disrupting properties of xenobiotics. Thus tissue-specific expression and regulation of multiple xenobiotic-metabolizing enzymes are likely to play an important role in chemically induced disorders of male reproductive organs. Recent studies suggest that genetic polymorphisms underlying inter-individual and inter-ethnic variability of xenobiotic metabolism modulate susceptibility to male reproductive disorders. For cytochrome P450 1A1 (CYP1A1), a key enzyme in extra-hepatic metabolic activation of lipophilic xenobiotics, increased frequencies of two genetically linked polymorphisms have been found among infertile men.

Nickel serves as a substrate recognition motif for the endopeptidase involved in hydrogenase maturation

The interaction of the hydrogenase maturation endopeptidase HycI with its substrate, the precursor of the large subunit, was studied. Replacement of conserved amino-acid residues in HycI, which have been shown to bind a cadmium ion from the crystallization buffer in crystals of HybD (endopeptidase for hydrogenase 2), abolished or strongly reduced processing activity. Atomic absorption spectroscopy of purified HycI and HybD proteins showed the absence of nickel. In vitro processing assays showed that the reaction requires nickel to be bound to the precursor and the protease does not have a function in nickel delivery to the substrate. Radioactive labelling of cells with 63Ni, devoid of endopeptidase, resolved several forms of the precursor which are possibly intermediates in the maturation pathway. It is concluded that the endopeptidase uses the metal in the large subunit of [NiFe]-hydrogenases as a recognition motif.

Simultaneous avulsion fracture of the insertion of the ulnar and radial collateral ligaments of the metacarpophalangeal joint of the thumb

We present a case of simultaneous avulsion fracture of the insertion on the volar base of the proximal phalanx of the ulnar and radial collateral ligaments of the metacarpophalangeal joint of the thumb. To our knowledge this combination has never been published before. The mechanism of this injury is not clearly understood.

Polymorphisms of the xenobiotic-metabolizing enzymes CYP1A1 and NAT-2 in systemic sclerosis and lupus erythematosus

The etiology of systemic autoimmune diseases, such as systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) is still unknown. In several cases, however, xenobiotics (i.e. drugs and occupational agents) were identified as etiologic agents and associations with certain polymorphic alleles of xenobiotic-metabolizing enzymes have been reported. Cytochrome P4501A1 (CYP1A1) and N-acetyltransferase 2 (NAT-2) are xenobiotic-metabolizing enzymes of phase 1- and phase 2-metabolism, respectively. CYP1A1 may activate drugs and other chemicals to reactive metabolites. NAT-2 is the most important enzyme in acetylation of aromatic amines, and thus may be responsible for detoxification of many of these compounds. Two polymorphisms of the human CYP1A1 gene, a point mutation in the 3' flanking region of the gene (Msp1) and a mutation in exon 7 leading to an isoleucine-valine-exchange in the heme-binding region of the enzyme, have been described and may lead to a higher basal and inducible enzyme activity. With respect to NAT-2, several alleles which combine for the two phenotypes "fast" and "slow" acetylators have been described. We analyzed the gene frequencies of the CYP1A1 polymorphisms and the phenotypes of NAT-2 in patients suffering from idiopathic SLE or SSc. CYP1A1 polymorphisms were analyzed in genomic DNA by PCR, whereas NAT-2 phenotypes were measured by the caffeine method. For CYP1A1 polymorphisms, 106 patients have been typed until now. The SLE group (n = 68) exhibited a significant increase (p < 0.05) in the mutant Val-allele (OR = 2.59) when compared to controls (n = 184). However, no significant differences in allele frequencies for MspI in the SLE group and for both CYP1A1 polymorphisms in the SSc group could be observed. Regarding the NAT-2 phenotype, patients suffering from SLE (n = 88) 75% and SSc (n = 26) 80.2%, respectively, were slow acetylators compared to 55% slow acetylators in the healthy German population (p < 0.05). The observed increased frequencies of the CYP1A1 mutant Val-allele and the slow actylator phenotype in idiopathic autoimmune disease support our concept that in slow acetylators non-acetylated xenobiotics may accumulate and are subsequently metabolized by other enzymes into reactive intermediates. Thus, enhanced formation of reactive metabolites could alter self-proteins presented to the immune system thus stimulating autoreactive T cells which induce autoimmunity.

Hypothenar hammer syndrome. Retrospective study of nine cases

The hypothenar hammer syndrome is an uncommon lesion of the ulnar artery caused by repetitive trauma to the ulnar portion of the hand. It characteristically occurs in the dominant hand of middle-aged craftsmen, but also in athletes practising various types of sports. We present a retrospective study of nine patients between 1988 and 1999. The follow-up ranged from 1 to 10 years. We recommend surgical treatment, by resection of the involved arterial segment and revascularization either by direct anastomosis or by means of a venous interpositional graft.

Crystal structure of the hydrogenase maturating endopeptidase HYBD from Escherichia coli

The maturation of [NiFe] hydrogenases includes formation of the nickel metallocenter, proteolytic processing of the metal center carrying large subunit, and its assembling with other hydrogenase subunits. The hydrogenase maturating enzyme HYBD from Escherichia coli, a protease of molecular mass 17.5 kDa, specifically cleaves off a 15 amino acid peptide from the C terminus of the precursor of the large subunit of hydrogenase 2 in a nickel-dependent manner. Here we report the crystal structure of HYBD at 2.2 A resolution. It consists of a twisted five-stranded beta-sheet surrounded by four and three helices, respectively, on each side. A cadmium ion from the crystallization buffer binds to the proposed nickel-binding site and is penta-coordinated by Glu16, Asp62, His93, and a water molecule in a pseudo-tetragonal arrangement. HYBD is topologically related to members of the metzincins superfamily of zinc endoproteinases, sharing the central beta-sheet and three helices. In contrast to the metzincins, the metal-binding site of HYBD is localized at the C-terminal end of the beta-sheet. Three helical insertions unique to HYBD pack against one side of the sheet, build up the active site cleft, and provide His93 as ligand to the metal. From this structure, we derive molecular clues into how the protease HYBD is involved in the hydrogenase maturation process.

The ligand-induced structural changes of human L-Arginine:Glycine amidinotransferase. A mutational and crystallographic study

Human L-arginine:glycine amidinotransferase (AT) shows large structural changes of the 300-flap and of helix H9 upon binding of L-arginine and L-ornithine, described as a closed and an open conformation (Humm, A., Fritsche, E., Steinbacher, S., and Huber, R. (1997) EMBO J. 16, 3373-3385). To elucidate the structural basis of these induced-fit movements, the x-ray structures of AT in complex with the amidino acceptor glycine and its analogs gamma-aminobutyric acid and delta-aminovaleric acid, as well as in complex with the amidino donor analogs L-alanine, L-alpha-aminobutyric acid, and L-norvaline, have been solved at 2.6-, 2.5-, 2.37-, 2.3-, 2.5-, and 2.4-A resolutions, respectively. The latter three compounds were found to stabilize the open conformer. The glycine analogs bind in a distinct manner and do not induce the transition to the open state. The complex with glycine revealed a third binding mode, reflecting the rather broad substrate specificity of AT. These findings identified a role for the alpha-amino group of the ligand in stabilizing the open conformer. The kinetic, structural, and thermodynamic properties of the mutants ATDeltaM302 and ATDelta11 (lacks 11 residues of H9) confirmed the key role of Asn300 and suggest that in mammalian amidinotransferases, the role of helix H9 is in accelerating amidino transfer by an induced-fit mechanism. Helix H9 does not add to the stability of the protein.

[Soft tissue reconstruction of the finger with free, posterior ramus of the anterior interosseous artery-based septo-cutaneous flap. Anatomy--technique--case examples]

In cases of larger soft-tissue defects of the fingers which cannot be covered with local or regional flaps, pedicled or even free flaps can be used. Pedicled flaps and most free flaps are too bulky and need several trimmings before a cosmetically and functionally satisfactory result is achieved. Free flaps used for soft-tissue reconstruction in digits should be thin and should have a low donor-site morbidity. The free flaps based on the anterior interosseous artery, especially the one based on the dorsal branch, are ideal for soft-tissue reconstruction of single digits. They are very thin and can be harvested in the same operative field. Donor-site morbidity is usually low. The clinical usefullness of this flap is shown in the reconstruction of three consecutive cases of severely damaged fingers.

Crystal structure of L-arginine:inosamine-phosphate amidinotransferase StrB1 from Streptomyces griseus: an enzyme involved in streptomycin biosynthesis

Inosamine-phosphate amidinotransferases catalyze two nonconsecutive transamidination reactions in the biosynthesis of the streptomycin family of antibiotics. L-Arginine:inosamine-phosphate amidinotransferase StrB1 from Streptomyces griseus (StrB1) was cloned as an N-terminal hexa-histidine fusion protein, purified by affinity chromatography, and crystallized, and its crystal structure was solved by Patterson search methods at 3.1 A resolution. The structure is composed of five betabeta alphabeta-modules which are arranged circularly into a pseudo-5-fold symmetric particle. The three-dimensional structure is closely related to the structure of human L-arginine:glycine amidinotransferase (AT), but five loops (the 40-, 170-, 220-, 250-, and 270-loop) are organized very differently. The major changes are found in loops around the active site which open the narrow active site channel of AT to form an open and solvent-exposed cavity. In particular, module II of StrB1 is AT-like but lacks a 10-residue alpha-helix in the 170-loop. The concomitant reorganization of neighboring surface loops that surround the active site, i.e., the 40-loop and the 270-loop, results in an arrangement of loops which allows an unrestricted access of substrates to the cavity. However, the residues which are involved in substrate binding and catalysis are conserved in AT and StrB1 and are at equivalent topological positions, suggesting a similar reaction mechanism among amidinotransferases. The binding site for L-arginine had been deduced from its complex with AT. Molecular modeling revealed a possible binding mode for the second substrate scyllo-inosamine 4-phosphate.

Increased frequencies of cytochrome P4501A1 polymorphisms in infertile men

Genetic factors that could mediate the pathogenesis of male reproductive disorders are largely unclear. Polymorphisms of cytochrome P4501A1 (CYP1A1), a key enzyme in the extrahepatic metabolism of lipophilic xenobiotics, have been shown to influence susceptibility to xenobiotics. Here, CYP1A1 polymorphisms were investigated in 134 infertile Caucasian men. The frequencies of the Mspl polymorphism in the 3'-flanking region of the CYP1A1 gene and a mutation in exon 7 causing an isoleucine-valine exchange (IVE) in the heme-binding region of the enzyme were increased among infertile men when compared with those of unselected, healthy male controls (odds ratio (OR)) 1.4, Cl95 0.68-2.89 for Mspl polymorphism; OR 2.4, Cl95 0.83-6.95 for IVE). Patients with normozoospermia revealed the highest frequencies for both polymorphisms (n = 8; OR 4.5, Cl95 0.97-20.91 for Mspl polymorphism; OR 13.7, Cl95 2.53-74.13 for IVE). ORs for the IVE exceeded the values calculated for the Mspl polymorphism. These preliminary results suggest that genetic variation in the metabolism of xenobiotics may codetermine individual susceptibility to infertility.