The hairless mouse ear: an in vivo model for studying wound neovascularization

Microvascular ingrowth into damaged tissue is an essential component of the normal healing process. In fact, wound therapy is often aimed at promoting neovascularization. However, little is known about the mechanisms that regulate microvascular ingrowth into a healing wound. This limited knowledge is largely due to the lack of adequate models in which microvascular ingrowth can be quantitatively analyzed throughout the healing process. To address this deficiency, we developed a model in which a wound was created on the ear of the hairless mouse-a well established model for directly viewing and measuring skin microcirculation. While the animals were under ketamine and xylazine anesthesia, 2.25 mm diameter full-thickness wounds were created on the dorsum of hairless mouse ears down to but not including the cartilage (0.125 mm depth). With the use of video microscopy and computer-assisted digitized planimetry, the precise epithelial and neovascular wound edge was viewed and measured regularly throughout healing. Therefore, this model can provide objective data on wound epithelialization and neovascularization throughout healing. This model was used to examine the effect of topical wound agents on epithelialization and neovascularization. Differential effects by these anti-microbial agents on these two processes were observed, which suggests clinical implications for their use.

HOTAIR is a negative prognostic factor and exhibits pro-oncogenic activity in pancreatic cancer

HOTAIR is a long intervening non-coding RNA (lincRNA) that associates with the Polycomb Repressive Complex 2 (PRC2) and overexpression is correlated with poor survival for breast, colon and liver cancer patients. In this study, we show that HOTAIR expression is increased in pancreatic tumors compared to non-tumor tissue and is associated with more aggressive tumors. Knockdown of HOTAIR (siHOTAIR) by RNA interference shows that HOTAIR plays an important role in pancreatic cancer cell invasion and as reported in other cancer cell lines. In contrast, HOTAIR knockdown in Panc1 and L3.6pL pancreatic cancer cells that overexpress this lincRNA decreased cell proliferation, altered cell cycle progression, and induced apoptosis, demonstrating an expanded function for HOTAIR in pancreatic cancer cells compared to other cancer cell lines. Results of gene array studies showed that there was minimal overlap between HOTAIR-regulated genes in pancreatic vs. breast cancer cells and HOTAIR uniquely suppressed several interferon-related genes and gene sets related to cell cycle progression in pancreatic cancer cells and tumors. Analysis of selected genes suppressed by HOTAIR in Panc1 and L3.6 pL cells showed by knockdown of EZH2 and chromatin immunoprecipitation assays that HOTAIR-mediated gene repression was both PRC2-dependent and -independent. HOTAIR knockdown in L3.6pL cells inhibited tumor growth in mouse xenograft model, further demonstrating the pro-oncogenic function of HOTAIR in pancreatic cancer.

[Hereditary cutaneous leiomyomatosis]

The occurrence of multiple cutaneous leiomyomas can be indicative of hereditary cutaneous leiomyomatosis. This autosomal dominant disorder is due to germline mutations in the fumarate hydratase (FH) gene. Associations with uterine myomas and renal cell carcinomas have been described and are referred to as Multiple Cutaneous and Uterine Leiomyomas (MCUL) or Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC), respectively. A 34-year-old man presented with multiple red-brown papules and nodules. After histopathologic confirmation of piloleiomyomas, we made the diagnosis of hereditary cutaneous leiomyomatosis. Taking into consideration the aforementioned complications, close interdisciplinary management of these patients and regular screening examinations within affected families are mandatory.

Extended haplotype studies in South African and Dutch variegate porphyria families carrying the recurrent p.R59W mutation confirm a common ancestry

BACKGROUND

Variegate porphyria (VP) is due to a partial deficiency of protoporphyrinogen oxidase (PPOX), the seventh enzyme in the haem biosynthetic pathway. Clinically, VP is characterized by photosensitivity and acute neurovisceral attacks that can manifest separately or together in affected individuals. The disease is inherited in an autosomal dominant fashion with incomplete penetrance and PPOX gene mutations associated with VP are usually unique to patients and their families. In South Africa, however, VP is highly prevalent as the result of a founder mutation, designated p.R59W. Previous genealogical and haplotype studies showed a link between South African and Dutch carriers of p.R59W and it was suggested that this mutation was introduced to South Africa by Dutch settlers at the end of the 17th century.

OBJECTIVES

To perform extended haplotype analysis in six South African and Dutch VP families with the p.R59W mutation.

METHODS

Haplotyping of 13 microsatellite markers flanking the PPOX gene on chromosome 1q22-23 and five informative single nucleotide polymorphisms within and around the gene.

RESULTS

A core haplotype cosegregated in all families studied.

CONCLUSIONS

Our data deliver further confirmation that the South African and Dutch VP families carrying mutation p.R59W shared a common ancestor.

Using cohort studies in lifecourse epidemiology

The UK Medical Research Council (MRC) Population Health Sciences Research Network is a network of MRC research units and centres that aims to bring together and add value to existing MRC investment in public health, health services and epidemiological research. This symposium held in August 2011 at the World Congress of Epidemiology, Edinburgh, discussed a range of topics including methodology and analytical issues based on a number of examples of cohort studies within the context of lifecourse epidemiology.

Under-three minute PCR: probing the limits of fast amplification

Nucleic acid amplification is enormously useful to the biotechnology and clinical diagnostic communities; however, to date point-of-use PCR has been hindered by thermal cycling architectures and protocols that do not allow for near-instantaneous results. In this work we demonstrate PCR amplification of synthetic SARS respiratory pathogenic targets and bacterial genomic DNA in less than three minutes in a hardware configuration utilizing convenient sample loading and disposal. Instead of sample miniaturization techniques, near-instantaneous heating and cooling of 5 μL reaction volumes is enabled by convective heat transfer of a thermal fluid through porous media combined with an integrated electrical heater. This method of rapid heat transfer has enabled 30 cycles of PCR amplification to be completed in as little as two minutes and eighteen seconds. Surprisingly, multiple enzymes have been shown to work at these breakthrough speeds on our system. A tool for measuring enzyme kinetics now exists and can allow polymerase optimization through directed evolution studies. Pairing this instrument technology with modified polymerases should result in a new paradigm for high-throughput, ultra-fast PCR and will hopefully improve our ability to quickly respond to the next viral pandemic.

Hereditary tumour syndromes featuring basal cell carcinomas

Basal cell carcinoma (BCC) is the most frequent cutaneous malignancy worldwide. This skin tumour is characterized by a broad phenotypic variability and distinct histopathological subtypes. It shows slow, locally invasive growth and only rarely metastasizes. BCCs can occur either sporadically or in the context of genetic syndromes, including Gorlin syndrome, Bazex-Dupré-Christol syndrome, Rombo syndrome, Oley syndrome and xeroderma pigmentosum. Different genes and signalling routes have been shown to play an important role in the development and growth of these tumours, including the hedgehog and Wnt/β-catenin pathway. In some of the aforementioned hereditary disorders the underlying genetic defect is still unknown whereas in others several genes have been demonstrated to be involved. Currently, most therapeutic approaches are based on surgical measures. In the case of superficial BCCs, photodynamic therapy, 5-fluorouracil cream, imiquimod or radiotherapy also may be an option. Elucidation of the molecular mechanisms governing the manifestation of BCCs in monogenetically inherited tumour syndromes will not only contribute to a better understanding of the complex pathogenesis of these tumours but might pave the way to the development of noninvasive, specific and molecule-based therapeutic strategies in the near future.

Hereditary leiomyomatosis and renal cell cancer in families referred for fumarate hydratase germline mutation analysis

Heterozygous fumarate hydratase (FH) germline mutations cause hereditary leiomyomatosis and renal cell cancer (HLRCC), an autosomal dominant syndrome characterized by multiple cutaneous piloleiomyomas, uterine leiomyomas and papillary type 2 renal cancer. The main objective of our study was to evaluate clinical and genetic data from families suspected of HLRCC on a nationwide level. All families referred for FH mutation analysis in the Netherlands were assessed. We performed FH sequence analysis and multiplex ligation-dependent probe amplification. Families with similar FH mutations were examined for haplotype sharing. In 14 out of 33 families, we identified 11 different pathogenic FH germline mutations, including 4 novel mutations and 1 whole-gene deletion. Clinical data were available for 35 FH mutation carriers. Cutaneous leiomyomas were present in all FH mutation carriers older than 40 years of age. Eleven out of 21 female FH mutation carriers underwent surgical treatment for symptomatic uterine leiomyomas at an average of 35 years. Two FH mutation carriers had papillary type 2 renal cancer and Wilms' tumour, respectively. We evaluated the relevance of our findings for clinical practice and have proposed clinical diagnostic criteria, indications for FH mutation analysis and recommendations for management.

[Treatment of complex elbow injuries with the hinged fixation device DJD II. Technique and results]

Fractures and luxations with persistent instability of the elbow are severe injuries often followed by arthrofibrosis. The need for prolonged immobilization results in shortage of the ligaments and shrinking of the capsule. Treatment with dynamic hinged external fixation offers an option of protected early mobilization providing better results and avoiding stiffness and instability. In a retrospective study 22 patients with complex injuries of the elbow were evaluated with respect to the range of motion and subjective parameters (DASH score, DASH disabilities of the arm, shoulder and hand).

Impact of antiretroviral treatment on (13) C-methionine metabolism as a marker of hepatic mitochondrial function: a longitudinal study

OBJECTIVES

Uncontrolled viral replication and antiretroviral treatment (ART) may independently contribute to hepatic mitochondrial toxicity. The present study was designed to explore the longitudinal effects of treatment modifications on hepatic mitochondrial function by means of noninvasive (13) C-methionine breath test (MeBT) diagnostics.

METHODS

A total of 113 HIV-infected patients underwent two consecutive MeBTs over an interval of 11.8±3.5 months. Forty-nine patients remained on stable ART or no therapy; 28 participants switched ART; 27 patients (re)initiated ART, and nine individuals underwent a structured treatment interruption (STI) of ART between MeBTs 1 and 2. Breath test results were expressed as cumulative percentage dose of (13) CO(2) recovered after 1.5 h test time (cPDR(1.5h) ).

RESULTS

Initiation of ART in treatment-naïve individuals and patients on STI was associated with a significant improvement of hepatic mitochondrial function (P<0.05). Cessation of ART or a prolonged delay in initiating therapy in treatment-naïve patients in turn led to a significant decline of (13) C-exhalation compared with baseline (P<0.05). A marked increase in (13) C-exhalation was observed in individuals who switched from stavudine or ddI to tenofovir or abacavir (+170%; P<0.001), while no differences between MeBTs 1 and 2 were found in individuals on ART who had remained on stable regimens or in those who changed a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI) component.

CONCLUSION

The present data suggest that hepatic mitochondrial function in HIV disease is a dynamic process with a high regenerative capacity and highlight the pathogenic relevance of HIV replication. Our findings suggest that modern ART per se does not negatively impact hepatic mitochondrial function.

Endothelial progenitor cells correlate with lesion volume and growth in acute stroke

OBJECTIVES

Circulating endothelial progenitor cells (EPC) are markers of vascular injury and their numbers decrease in acute stroke. However, the relation of EPC levels to stroke severity has not been quantified. MRI measurements of lesion volume provide an objective method for stroke severity assessment and outcome prediction. This cross-sectional study aims to determine whether EPC are correlated with lesion volume at baseline, lesion growth, and final lesion volume.

METHODS

Seventeen patients (median age 63 years, NIH Stroke Scale score 7) were selected from 175 patients with imaging-confirmed acute ischemic stroke. EPC were quantified by flow cytometry using CD34, CD133, and VEGFR2 surface markers. Brain MRI was performed at baseline and at days 1 and 5 after the stroke onset. Stroke lesion volumes were quantified.

RESULTS

Larger lesion volumes measured on diffusion-weighted images (DWI) at baseline were associated with low EPC levels, while smaller lesion volumes and less lesion growth were linked with high levels of EPC subsets (CD34+CD133+, CD133+VEGFR2+, and CD34+ CD133+VEGFR2+). Similar results were observed with DWI lesion volumes and EPC (CD34+CD133+) on day 1. Lesion growth volume, represented as a difference between final lesion volume and baseline DWI, was larger in patients with lower day 1 EPC (CD133+VEGFR2+). After adjustments for age and admission glucose (model 1), mean arterial pressure and white blood cells (model 2), INR and hematocrit (model 3), the CD34+CD133+ subset remained predictive of baseline and day 1 lesion volumes, while CD133+VEGFR2+ predicted baseline lesion volume and growth of lesion volume.

CONCLUSIONS

Higher EPC levels were indicative of smaller volumes of acute lesion, final lesion, and lesion growth, and may serve as markers of acute phase stroke severity. However, a larger prospective study is needed to confirm our findings.

[A transparent, internal complication management concept: results and consequences]

INTRODUCTION

The acquisition of data and public discussion of complications after therapeutic procedures and surgeries is a sensitive subject, which is mostly avoided even in department meetings. However, it is evident that the broad discussion and the expression of different opinions and aspects provide useful information for continuous improvements. Therefore, we established a system for the transparent acquisition of complications in our department.

METHOD

Since January 2005, we systematically register operative and non-operative complications at our department, evaluate them and therefore gain a great benefit. All the complications are presented, discussed and evaluated within the weekly morbidity and mortality conferences.

RESULTS

In 2005 and 2006, among a total number of 2730 and, respectively, 3124 operations, 102 (3.7 %) and 71 (2.3 %) complications have been registered and analysed according to different criteria. We have distinguished between complications which required surgery and complications which only required conservative treatment. There was a higher number of complications which needed surgery. In this group, the most common complications have been found in vertebral spine surgery. The groups of complications with conservative treatment were mostly related to nerve lesions and deep venous thrombosis. With the aid of the internal department evaluation of the registered data, especially the number of complications in vertebral spine surgery could be clearly reduced in 2006.

CONCLUSION

The described method has created a transparency of occurring complications because each colleague is informed as well as involved in the solution process. Furthermore, it is planned to evaluate the impact of risk factors on the various performed surgeries.