Wearing face masks as a potential source for inhalation and oral uptake of inanimate toxins - A scoping review

BACKGROUND

From 2020 to 2023 many people around the world were forced to wear masks for large proportions of the day based on mandates and laws. We aimed to study the potential of face masks for the content and release of inanimate toxins.

METHODS

A scoping review of 1003 studies was performed (database search in PubMed/MEDLINE, qualitative and quantitative evaluation).

RESULTS

24 studies were included (experimental time 17 min to 15 days) evaluating content and/or release in 631 masks (273 surgical, 228 textile and 130 N95 masks). Most studies (63%) showed alarming results with high micro- and nanoplastics (MPs and NPs) release and exceedances could also be evidenced for volatile organic compounds (VOCs), xylene, acrolein, per-/polyfluoroalkyl substances (PFAS), phthalates (including di(2-ethylhexyl)-phthalate, DEHP) and for Pb, Cd, Co, Cu, Sb and TiO2.

DISCUSSION

Of course, masks filter larger dirt and plastic particles and fibers from the air we breathe and have specific indications, but according to our data they also carry risks. Depending on the application, a risk-benefit analysis is necessary.

CONCLUSION

Undoubtedly, mask mandates during the SARS-CoV-2 pandemic have been generating an additional source of potentially harmful exposition to toxins with health threatening and carcinogenic properties at population level with almost zero distance to the airways.

Mechanical ileus of the small bowel due to an inflamed Meckel's diverticulum with an enterolith - a case report with literature review

BACKGROUND

Meckel's diverticula result from incomplete obliteration and regression of the omphaloenteric duct and are the most common congenital intestinal malformations. Many Meckel's diverticula remain asymptomatic and are discovered as incidental findings. They present a diagnostic challenge.

METHODS

We report the case of a 35-year-old man who presented with an acute abdomen and ileus. Computed tomography of the abdomen showed a mechanical small bowel ileus. There was a calibre jump in the terminal ileum with a round endoluminal definable hyperdense structure of almost 2 cm in diameter.

RESULTS

An exploratory laparoscopy was performed revealing an inflamed Meckel's diverticulum with impacted enterolith as the cause of the intestinal obstruction.

CONCLUSION

In symptomatic Meckel's diverticula, haemorrhage and obstruction are the most common complications. The development of ileus due to a Meckel's diverticulum with an enterolith is considered extremely rare but should be taken into account.

Characterization in respect to degradation of titanium-coated polypropylene surgical mesh explanted from humans

Titanium-coated polypropylene (Ti-PP) mesh was introduced in 2002 as a surgical mesh for the treatment of hernias and shortly after for pelvic floor surgery, with the aim of improving biocompatibility when compared to non-titanised/regular PP mesh implants. The application of a titanium coating could also be beneficial to address concerns regarding the exposure of PP in an in vivo environment. Many studies have shown that PP, although it is widely accepted as a stable polymer, is subject to oxidation and degradation, such degradation affects the mechanical behavior, that is, the stiffness and tensile strength of PP mesh. Despite the wide clinical use of Ti-PP surgical meshes, no study has yet investigated the residual material properties post clinical deployment and subsequent explantation. In this study, two explanted Ti-PP mesh samples each having different incorporation durations from two patients were examined. Material analysis conducted within this study includes the following techniques: attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, low voltage - scanning electron microscopy (LV-SEM), backscattered electron (BSE) imaging, energy dispersive X-ray spectroscopy (EDS) and secondary election hyperspectral imaging (SEHI). The hypothesis of this study is that the Ti coating successfully shields the PP mesh from oxidative stress in vivo and thus protects it from degradation. The results of this analysis show for the first time evidence of bulk oxidation, surface degradation, and environmental stress cracking on explanted Ti-PP meshes.

Physio-metabolic and clinical consequences of wearing face masks—Systematic review with meta-analysis and comprehensive evaluation

Background

As face masks became mandatory in most countries during the COVID-19 pandemic, adverse effects require substantiated investigation.

Methods

A systematic review of 2,168 studies on adverse medical mask effects yielded 54 publications for synthesis and 37 studies for meta-analysis (on n = 8,641, m = 2,482, f = 6,159, age = 34.8 ± 12.5). The median trial duration was only 18 min (IQR = 50) for our comprehensive evaluation of mask induced physio-metabolic and clinical outcomes.

Results

We found significant effects in both medical surgical and N95 masks, with a greater impact of the second. These effects included decreased SpO2 (overall Standard Mean Difference, SMD = −0.24, 95% CI = −0.38 to −0.11, p < 0.001) and minute ventilation (SMD = −0.72, 95% CI = −0.99 to −0.46, p < 0.001), simultaneous increased in blood-CO2 (SMD = +0.64, 95% CI = 0.31–0.96, p < 0.001), heart rate (N95: SMD = +0.22, 95% CI = 0.03–0.41, p = 0.02), systolic blood pressure (surgical: SMD = +0.21, 95% CI = 0.03–0.39, p = 0.02), skin temperature (overall SMD = +0.80 95% CI = 0.23–1.38, p = 0.006) and humidity (SMD +2.24, 95% CI = 1.32–3.17, p < 0.001). Effects on exertion (overall SMD = +0.9, surgical = +0.63, N95 = +1.19), discomfort (SMD = +1.16), dyspnoea (SMD = +1.46), heat (SMD = +0.70), and humidity (SMD = +0.9) were significant in n = 373 with a robust relationship to mask wearing (p < 0.006 to p < 0.001). Pooled symptom prevalence (n = 8,128) was significant for: headache (62%, p < 0.001), acne (38%, p < 0.001), skin irritation (36%, p < 0.001), dyspnoea (33%, p < 0.001), heat (26%, p < 0.001), itching (26%, p < 0.001), voice disorder (23%, p < 0.03), and dizziness (5%, p = 0.01).

Discussion

Masks interfered with O2-uptake and CO2-release and compromised respiratory compensation. Though evaluated wearing durations are shorter than daily/prolonged use, outcomes independently validate mask-induced exhaustion-syndrome (MIES) and down-stream physio-metabolic disfunctions. MIES can have long-term clinical consequences, especially for vulnerable groups. So far, several mask related symptoms may have been misinterpreted as long COVID-19 symptoms. In any case, the possible MIES contrasts with the WHO definition of health.

Conclusion

Face mask side-effects must be assessed (risk-benefit) against the available evidence of their effectiveness against viral transmissions. In the absence of strong empirical evidence of effectiveness, mask wearing should not be mandated let alone enforced by law.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021256694, identifier: PROSPERO 2021 CRD42021256694.

Possible toxicity of chronic carbon dioxide exposure associated with face mask use, particularly in pregnant women, children and adolescents - A scoping review

Introduction

During the SARS-CoV-2-pandemic, face masks have become one of the most important ubiquitous factors affecting human breathing. It increases the resistance and dead space volume leading to a re-breathing of CO2. So far, this phenomenon and possible implications on early life has not been evaluated in depth.

Method

As part of a scoping review, literature was systematically reviewed regarding CO2 exposure and facemask use.

Results

Fresh air has around 0.04% CO2, while wearing masks more than 5 min bears a possible chronic exposure to carbon dioxide of 1.41% to 3.2% of the inhaled air. Although the buildup is usually within the short-term exposure limits, long-term exceedances and consequences must be considered due to experimental data. US Navy toxicity experts set the exposure limits for submarines carrying a female crew to 0.8% CO2 based on animal studies which indicated an increased risk for stillbirths. Additionally, mammals who were chronically exposed to 0.3% CO2 the experimental data demonstrate a teratogenicity with irreversible neuron damage in the offspring, reduced spatial learning caused by brainstem neuron apoptosis and reduced circulating levels of the insulin-like growth factor-1. With significant impact on three readout parameters (morphological, functional, marker) this chronic 0.3% CO2 exposure has to be defined as being toxic. Additional data exists on the exposure of chronic 0.3% CO2 in adolescent mammals causing neuron destruction, which includes less activity, increased anxiety and impaired learning and memory. There is also data indicating testicular toxicity in adolescents at CO2 inhalation concentrations above 0.5%.

Discussion

There is a possible negative impact risk by imposing extended mask mandates especially for vulnerable subgroups. Circumstantial evidence exists that extended mask use may be related to current observations of stillbirths and to reduced verbal motor and overall cognitive performance in children born during the pandemic. A need exists to reconsider mask mandates.

Influence of polypropylene mesh degradation on tissue inflammatory reaction

Polypropylene degradation in vivo appears as mesh surface cracking and peeling. This aging process of the mesh, resulting in the lack of bio-stability, contradicts the requirement of biocompatibility. However, to date, it is still not clearly established how much this mesh degradation influences the local tissue response with subsequent clinical consequences. This study aims to find out whether mesh degradation is correlated with elevated inflammatory tissue reaction through analyzing 100 human PP meshes explanted from the pelvic floor. A degradation classification method, based on standard pathological H&E stained slides of the explanted mesh via light microscope, was developed to classify the mesh degradation into four classes (no, mild, moderate and severe degradation). The peri-filamentary tissue inflammatory reaction was analyzed by scoring the expression of the most common cell markers for the innate immune reaction: CD68 as marker for macrophage, CD86 for M1 subtype, CD163 for M2 subtype, CD3 for T-lymphocyte and CD15 for neutrophil granulocytes. The correlation between immune cell expression, degradation classification and time of implantation of the meshes are evaluated with Spearman-Rho-Test. Mesh degradation worsens significantly (p < .001) with longer time of implantation. The increasing tendency of CD68 expression by mesh with higher degradation class indicates that the number of macrophages increases with worsening mesh degradation. The significantly increased expression of CD163 and CD3 cell by severely degraded mesh demonstrate the increased number of M2 and T-Lymphocyte when mesh degradation becomes severe. None of the inflammatory cells show the usual declining expression with longer time of implantation. The result of this study suggests that the degradation of PP mesh results in an elevated local inflammatory reaction in female pelvic floor. A material with better bio-stability for mesh implant in pelvic floor is required.

Are late hernia mesh complications linked to Staphylococci biofilms?

Purpose

The purpose of this study was to investigate the link between bacterial biofilms and negative outcomes of hernia repair surgery. As biofilms are known to play a role in mesh-related infections, we investigated the presence of biofilms on hernia meshes, which had to be explanted due to mesh failure without showing signs of bacterial infection.

Methods

In this retrospective observational study, 20 paraffin-embedded tissue sections from explanted groin hernia meshes were analysed. Meshes have been removed due to chronic pain, hernia recurrence or mesh shrinkage. The presence and bacterial composition of biofilms were determined. First, specimens were stained with fluorescence in situ hybridisation (FISH) probes, specific for Staphylococcus aureus and coagulase-negative staphylococci, and visualised by confocal laser scanning microscopy. Second, DNA was extracted from tissue and identified by S. aureus and S. epidermidis specific PCR.

Results

Confocal microscopy showed evidence of bacterial biofilms on meshes in 15/20 (75.0%) samples, of which 3 were positive for S. aureus, 3 for coagulase-negative staphylococci and 9 for both species. PCR analysis identified biofilms in 17/20 (85.0%) samples, of which 4 were positive for S. aureus, 4 for S. epidermidis and 9 for both species. Combined results from FISH/microscopy and PCR identified staphylococci biofilms in 19/20 (95.0%) mesh samples. Only 1 (5.0%) mesh sample was negative for bacterial biofilm by both techniques.

Conclusion

Results suggest that staphylococci biofilms may be associated with hernia repair failure. A silent, undetected biofilm infection could contribute to mesh complications, chronic pain and exacerbation of disease.

P137 DEGRADATION RESISTANCE OF PVDF MESH IN VIVO IN COMPARISON TO PP MESH

Aim

To researched the degradation resistance of PVDF mesh by comparing its morphological and chemical condition with PP mesh.

Material and Methods

PVDF and PP meshes analysed in this study were received from a previous animal experiment. To expose the surface of explanted meshes, a tissue removing method with protease was used and the result of this cleaning process was tested by X-ray Photoelectron Spectroscopy (XPS). The morphological condition of the mesh surface was compared using Scanning Electron Microscopy (SEM) and the chemical condition concerning degradation was analysed through Fourier Transform Infrared Spectroscopy (FTIR). The surface condition of PVDF mesh after 3-, 6-, 12- and 24-month implantation was illustrated and compared with two types of PP meshes.

Results

XPS revealed an absence of nitrogen, confirming the successful removal of tissue residues using protease. SEM results presented no notable morphological surface change of the PVDF mesh and progressive surface cracking processes over time of both types of PP meshes. FTIR spectra of the implanted PVDF meshes had no considerable difference from the spectrum of the pristine mesh, while FTIR spectra of both types of PP meshes had extra chemical functional groups increasing with implantation time, indicating progressive degradation.

Conclusions

PVDF mesh does not show signs of degradation up to 24 months after implantation while PP meshes progressively degrade with increasing time under the same conditions, which appears as worsening Environmental Stress Cracks. This study highlights the morphological and chemical stability of the PVDF mesh and demonstrates that the PVDF mesh is more resistant to degradation in comparison to the PP meshes.

Degradation resistance of PVDF mesh in vivo in comparison to PP mesh

Mesh implant has been applied in hernia repair and urogynecological reconstruction. Polypropylene (PP) is now the most widely used material for non-resorbable mesh implants. A degradation phenomenon of PP mesh, which is apparent on the mesh surface as cracking, flaking and peeling, was discovered in the 1990's. This phenomenon of mesh implant has drawn attention because of mesh-related litigations. Polyvinylidene fluoride (PVDF), due to its high biocompatible performance, has been used since 2003 as an alternative material for non-resorbable mesh implants. Till now, no such degradation phenomenon of PVDF mesh has been reported, although limited study on PVDF mesh is available. In this paper, we researched the degradation of PVDF meshes taking the degradation of PP mesh as a reference. The meshes analysed in this study were received from a previous animal experiment. To expose the surface of explanted meshes, a tissue removing method with protease was used and the result of this cleaning process was tested by X-ray Photoelectron Spectroscopy (XPS). The morphological condition of the mesh surface was compared using Scanning Electron Microscopy (SEM) and the chemical condition concerning degradation was analysed through Fourier Transform Infrared Spectroscopy (FTIR). The surface condition of PVDF mesh after 3-, 6-, 12- and 24-month implantation was illustrated and compared with two types of PP meshes. XPS revealed an absence of nitrogen, confirming the successful removal of tissue residues using protease. SEM results presented no notable morphological surface change of the PVDF mesh and progressive surface cracking processes over time of both types of PP meshes. FTIR spectra of the implanted PVDF meshes had no considerable difference from the spectrum of the pristine mesh, while FTIR spectra of both types of PP meshes had extra chemical functional groups (carbonyl (CO) and hydroxyl (-OH) groups) increasing with implantation time, indicating progressive degradation. This study highlights the morphological and chemical stability of the PVDF mesh and demonstrates that the PVDF mesh is more resistant to degradation in comparison to the other two types of PP meshes.

Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards?

Many countries introduced the requirement to wear masks in public spaces for containing SARS-CoV-2 making it commonplace in 2020. Up until now, there has been no comprehensive investigation as to the adverse health effects masks can cause. The aim was to find, test, evaluate and compile scientifically proven related side effects of wearing masks. For a quantitative evaluation, 44 mostly experimental studies were referenced, and for a substantive evaluation, 65 publications were found. The literature revealed relevant adverse effects of masks in numerous disciplines. In this paper, we refer to the psychological and physical deterioration as well as multiple symptoms described because of their consistent, recurrent and uniform presentation from different disciplines as a Mask-Induced Exhaustion Syndrome (MIES). We objectified evaluation evidenced changes in respiratory physiology of mask wearers with significant correlation of O2 drop and fatigue (p < 0.05), a clustered co-occurrence of respiratory impairment and O2 drop (67%), N95 mask and CO2 rise (82%), N95 mask and O2 drop (72%), N95 mask and headache (60%), respiratory impairment and temperature rise (88%), but also temperature rise and moisture (100%) under the masks. Extended mask-wearing by the general population could lead to relevant effects and consequences in many medical fields.

Histological and SEM Assessment of Blood Stasis in Kidney Blood Vessels after Repeated Intra-Arterial Application of Radiographic Contrast Media

BACKGROUND

After application of iodinated contrast media (CM), a pronounced deterioration of the microcirculation in skin and myocardium was reported. Clinically, the repeated application of CM, especially, led to an increase of the renal resistance index (RRI). With respect to the transiency of the RRI increase, it is reasonable to assume that the deterioration of blood flow could be due to transient blood stasis caused by reversible morphologic cell alterations due to osmotic discrepancies between CM and human blood. Therefore, the hypothesis was investigated whether CM are able to induce in vivo such blood stasis and cell deformations in the renal vasculature of well-hydrated pigs.

METHODS

The in vivo study was performed as a prospective randomized examination to compare the effects of two different CM in 16 pigs (German Landrace). Pigs were randomized to receive either Iodixanol (n = 8), or Iopromide (n = 8). Each animal received 10 injections separated by 5-min intervals via the suprarenal aorta at a rate of 10 mL/s according to the usual procedure during a cardiac catheter examination. Finally, the kidneys were explanted and processed for histology (H & E staining and fibrin staining according to Weigert) as well as for scanning electron microscopy (SEM) with regards to morphologic correlates explaining the changes in the microcirculation.

RESULTS

In each of the predefined four categories of vascular diameters, blood stasis were found, but clearly more often after application of Iopromide than after application of Iodixanol (p < 0.001). In addition, Iopromide induced more blood stasis in all of the examined kidney regions compared to Iodixanol (p = 0.0001). There were no obstructive events in the middle cortex following the application of Iodixanol. Except for the region around a puncture channel of a placed-in catheter probe, no fibrin was detected in Weigert's fibrin-stained samples, neither around the histologically assessed thrombi nor in vessels with blood stasis. Complementary SEM analyses revealed in a few cases only a slight generation of fibrin and thrombi and deformations, such as echinocyte and "box-like" deformations.

CONCLUSIONS

According to previous in vitro studies, pathological erythrocyte deformations, such as echinocyte and box-like formation of erythrocytes, were observed also in vivo. In addition, blood stasis and/or thrombi could be detected in histological samples from explanted kidneys from young pigs after repeated in vivo administration of CM. In only a few cases, mural platelet aggregates within minimal fibrin meshes occurred only after the application of Iopromide.

CD68+ macrophages as crucial components of the foreign body reaction demonstrate an unconventional pattern of functional markers quantified by analysis with double fluorescence staining

Implants like meshes for the reinforcement of tissues implement the formation of a persistent inflammation with an ambient fibrotic reaction. In the inflammatory infiltrate several distinct cell types have been identified, but CD68+ macrophages are supposed to be most important. To investigate the collaboration among the various cell types within the infiltrate we performed at explanted meshes from humans double fluorescence staining with CD68 as a constant marker and a variety of other antibodies as the second marker. The list of second markers includes lymphocytes (CD3, CD4, CD8, CD16, CD56, FoxP3, and CD11b) stem cells (CD34), leucocytes (CD45, CD15), macrophages (CD86, CD105, CD163, and CD206); deposition of EC matrix (collagen-I, collagen-III, MMP2, and MMP8); Ki67 as a marker for proliferation; and the tyrosine-protein kinase receptor AXL. The present study demonstrates within the inflammatory infiltrate the abundant capability of CD68+ cells to co-express a huge variety of other markers, including those of lymphocytes, varying between 5 and 83% of investigated cells. The observation of co-staining was not restricted to a specific polymer but was seen with polypropylene fibers as well as with fibers made of polyvinylidene fluoride, although with differences in co-expression rates. The persisting variability of these cells without the functional reduction toward differentiated mature cell types may favor the lack of healing at the interface of meshes.

Mesh implants for hernia repair: an update

INTRODUCTION

Today the use of textile meshes has become a standard for the treatment of abdominal wall hernias and for the reinforcement of any tissue repair as the strength of the implant decreases the recurrence rates. With increasing use, side effects of the textile implants became apparent, as well.

AREAS COVERED

Based on publications in Medline over the past decade, general and specific benefits, as well as risks, are discussed with the challenge to define individual risk-benefit ratios. For meshes, certain high-risk or low-risk conditions can be defined. In an attempt to eliminate mesh-related risks, quality control for medical devices has meanwhile been revised. In both the USA and the EU post-market surveillance studies are required to keep medical devices approved.

EXPERT COMMENTARY

The impact of material on the complication rate will vary depending on the patient's co-morbidity or the risks of the procedure. Even the best material can end up with disappointing results in case of poor healing or poor surgery. On the other hand, when using high-risk devices, most of the complications after excellent surgery with excellent indication can be supposed to be mesh-related. Thus, the use of low-risk devices is recommended even though its advantage may not be demonstrable in clinical studies.

Enhancing Filtration Rates by the use of Blood Flow around the Capillaries of Plasmafilters: An in Vitro Study

As the low clearance rate of plasmaseparation limits its use in the treatment of patients suffering from liver failure, sepsis or MOF, we intend to develop strategies for a plasmaseparation unit which increases plasmafiltration rates. Our first question focused on whether commercially available plasmaseparation filters, and in particular their membranes, are suitable for the inversion of blood and plasma compartments. This experimental study was performed using in vitro systems. Commercially available plasmafilters PF2000N (Gambro) and Plasmaflo (Asahi) were compared in both their normal operating mode with blood flow through the capillary lumen, and in the inverse mode. Inverse mode means that blood flows through the outer space of the capillaries while plasma was obtained from the lumen. Heparinised porcine blood (5 I.U./ml) was used in a heated, recirculating in vitro circuit. Our main results were that the normal use of both filter types Plasmaflo and PF2000N enabled maximal blood flows (Qb) of 200 ml/min and filtration rates (Qf) of 25–40 ml/min. Operating the filters in the inverse mode enabled Qb up to 500 ml/min and Qf up to 100 ml/min. Hemolysis, platelet counts and coagulation parameters did not differ significantly regardless of whether the normal or inverse mode was used. The tested plasmafiltration membranes appear to be suitable for use in inverse mode. Although in our experiments, hemocompatibility tests did not indicate severe problems induced by the module geometry, the development of a module specially constructed for blood flow outside of the hollow fibers appears to be necessary in order to minimise shunts and low perfusion areas.

Concomitant Non-Small Cell Lung Cancer and Hairy Cell Leukemia in a Patient Harboring BRAF-V600E Mutation in Both Tissues: A Case Report

The BRAF-V600E mutation has been established as a signature alteration occurring almost universally in hairy cell leukemia. Moreover, it can be detected in a small percentage of patients with non-small cell lung cancer. We report the case of a patient with a metastatic BRAF-V600E-mutated lung adenocarcinoma suffering from concomitant hairy cell leukemia. The identification of an identical BRAF mutation in both malignancies raises physiopathological considerations and might offer unique therapeutic strategies for this group of patients.

Modulation of Pro- and Antifibrinolytic Properties of Human Peritoneal Mesothelial Cells by Transforming Growth Factor β1 (TGF- β1), Tumor Necrosis Factor α (TNF-α) and Interleukin β1 (IL-1β)

A decreased fibrinolytic activity of serosal surfaces appears to be a major factor in the development of peritoneal fibrous adhesions. Serosal fibrinolysis is regulated by mesothelial release of tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor types 1 and 2 (PAI-1 and PAI-2). We investigated the influence of tumor necrosis factor alpha (TNF-α), transforming growth factor β (TGF- β1) and interleukin 1β (IL-1β) on pro- and antifibrinolytic properties of mesothelial cells (HOMC) using a cell/fibrin clot assay. TGF-β1, TNF-α and IL-1β induced a dose dependent 2.9, 2.3 and 1.9-fold increase of PAI-1 antigen, respectively, whereas t-PA concentrations decreased to one third of the control values. This modified PAI-1/t-PA secretion pattern leads to a significant delay of fibrinolysis. Analysis of m-RNA levels revealed increased PAI-1 m-RNA concentrations after 12 h and decreased m-RNA concentrations for t-PA after 6 h. Serosal hypofibrinolysis during peritonitis may be explained at least in part by cytokine effects which thus may favor adhesion formation.

Sclerosing angiomatoid nodular transformation of the spleen mimicking metastasis of melanoma: a case report and review of the literature

BACKGROUND

Sclerosing angiomatoid nodular transformation is a benign disorder of splenic tissue and is often mistaken as a potentially malignant entity in the diagnostic process. To the best of our knowledge, this is the first report of sclerosing angiomatoid nodular transformation mimicking metastasis of melanoma in the literature.

CASE PRESENTATION

A 43-year-old white man presented with a newly found splenic mass 4 years ago to our Department of Gastroenterology. He was diagnosed as having a superficial spreading malignant melanoma localized at his left instep 7 years ago and was successfully treated with radical local resection. Several diagnostic procedures were conducted. Ultrasound showed a hypoechoic lesion in the inferior pole of his spleen with a diameter of 2 cm, blurred boundaries, and inhomogeneous interior pattern. Contrast-enhanced ultrasound was inconclusive and showed only discrete contrast enhancement of the lesion with accentuated nodule-like enrichment of the boundaries in the arterial phase. Computed tomography and magnetic resonance imaging scans showed two splenic lesions which were highly suspicious of metastasis. Magnetic resonance imaging of his head was inconspicuous. Bone scintigraphy showed no abnormal results. Fine-needle aspiration indicated metastasis of the above-mentioned malignant melanoma. We conducted a laparoscopic splenectomy. His intraoperative and postoperative course were uneventful. In contrast to the result of the fine-needle aspiration, the presence of metastasis of melanoma could not be confirmed. Histological analysis revealed nodule-like arrangement of fibroblasts with low cell density and a predominance of dilated capillaries, indicating sclerosing angiomatoid nodular transformation of the spleen.

CONCLUSIONS

There are no preoperative diagnostic imaging procedures which can definitely differentiate sclerosing angiomatoid nodular transformation from malignancies in cases of morphological and immunophenotypic variations of the specimen. Morphological and immunophenotypic variations of the specimen represent a diagnostic challenge and can mimic malignoma. As reported in our case, the specimen obtained by ultrasound-guided fine-needle aspiration led to the diagnosis of metastasis of melanoma. Splenectomy is often conducted due to a splenic mass suspicious of malignoma as described in our case or with unknown valency in different diagnostic imaging procedures.

Isolated Splenic Metastasis from Non-Small-Cell Lung Cancer: A Case Report and Review of the Literature

Metastases to the spleen are rare but have been reported for different tumor entities, including breast cancer, lung cancer, colorectal cancer, ovarian cancer, and melanoma. As an isolated event, splenic metastasis from non-small-cell lung cancer (NSCLC) is exceedingly rare. Until now, only 28 cases have been reported in the medical literature. We report the case of a 66-year-old woman with NSCLC (adenocarcinoma) who presented with a synchronous, isolated splenic metastasis. Operative removal of both primary tumor and metastasis was not possible due to multiple comorbidities. Therefore, treatment was limited to combined systemic chemotherapy and simultaneous radiation of the primary tumor, which led to partial remission of the disease. Isolated metastasis to the spleen in NSCLC has been reported only 28 times in the medical literature, most often in male patients with right-sided lung tumors, most of which were adenocarcinomas. The majority of patients were asymptomatic with respect to splenic metastasis. About half of the reported cases were isolated metachronous splenic metastases. Splenectomy seems to confer a survival advantage. We review the pertinent medical literature.

Cardioprotection by Carvedilol: Antiapoptosis is Independent of β-Adrenoceptor Blockage in the Rat Heart

Background: Carvedilol, a β-blocking agent with α-blocking properties is now widely used for the treatment of congestive heart failure. In addition to its β-adrenergic receptor blockage, antiapoptotic effects have been demonstrated in experimental animals.

Objective: The cardioprotective effects of carvedilol and its hydroxylated analogue BM-91.0228 were tested with regard to their infarct-limiting and antiapoptotic properties in an experimental infarct model in the rat heart.

Methods: Anesthetized rats were subjected to either 30 (groups I to 3) or 60 minutes (groups. 4 to 6) of coronary artery occlusion followed by 30 minutes of reperfusion. Groups 1 and 4 served as the control; groups 2 and 5 received intravenous Carvedilol (1 mg/kg) and groups 3 and 6 received intravenous administration of BM-91.0228 (1 mg/kg), respectively, 5 minutes prior to coronary occlusion. Infarct sizes were measured by triphenyltetrazolium chloride staining. In situ visualization of apoptosis was measured by nick end labeling.

Results: Carvedilol reduced infarct size after 30 minutes of coronary occlusion compared to controls (8.7% ± 2.7% versus 27.3% ± 3.4%, P < .001), while BM-91.0228 showed no significant infarct size reduction (23.7% ± 5.9%, NS). Neither Carvedilol (36.9% ± 3.9%) nor BM-91.0228 (42.4% ± 3.6%) reduced infarct size after 60 minutes of coronary occlusion compared to controls (47.7% ± 3.9%, NS). Carvedilol reduced apoptosis after 30 minutes (4.9% ± 1.3% versus 16.7% ± 3.2%, P < .01) and after 60 minutes (11.7% ± 1.8% versus 25.5% ± 0.5%, P < .001) of coronary occlusion compared to controls. BM-91.0228 reduced apoptosis after 30 minutes (7.3% ± 1.4% versus 16.7% ± 3.2%, P < .01) and after 60 minutes (13.4% ± 1.8% versus 25.5% ± 0.5%, P < .001) of coronary occlusion compared to controls.

Conclusion: Carvedilol is cardioprotective by preventing ischemia-perfusion-induced necrosis and apoptosis of cardiomyocytes. The antiapoptotic effects of Carvedilol are independent of its β-adrenoceptor blocking effects, but its effects might be caused by antioxidant properties and by modulation of the signalling pathway.

Host reaction to vaginally inserted collagen containing polypropylene implants in sheep

OBJECTIVE

We aimed to characterize the effect of vaginal or abdominal mesh insertion and of different collagen augmentation of polypropylene mesh in a sheep model. Outcome measures were passive and active biomechanical properties and semiquantitative morphometry.

STUDY DESIGN

Forty-two Texel sheep were used: 6 were nonimplanted controls (n = 6), the rest were implanted with polypropylene mesh (n = 12; Avaulta Solo; Bard Medical, Covington, GA) or collagen-coated meshes: Avaulta Plus (n = 12; Bard Medical) and Ugytex (n = 12; Sofradim International, Trevoux, France). Through a single incision, the rectovaginal septum was dissected and a 35 × 35-mm mesh was sutured to the underlying tissues. Abdominally, a 50 × 50-mm mesh was laid over a primarily sutured full thickness 40-mm longitudinal incisional defect. Animals were explanted after 60 or 180 days (n = 6 per group). Outcome measures were passive biomechanics by biaxial tensiometry, active contractility of vaginal explants, and histologic evidence.

RESULTS

Vaginal explants were 2.4 times stiffer compared with native vaginal tissue (P < .001), but without differences in comfort zone stiffness or slope of the load-elongation in the physiologic range between the products that were tested. Collagen coating was associated with a 16-fold reduction in contractile force at 180 days, compared with native vaginal tissue, both for Avaulta Plus (P = .032) and Ugytex (P = .015). Abdominal explants were 1.3-times stiffer compared with native abdominal wall tissue (P < .001) and were 1.9-times stiffer compared with vaginal explants.

CONCLUSION

Vaginal mesh implantation yields less stiff explants compared with abdominal explants. Vaginal mesh implantation also alters the passive and active biomechanical properties compared with native vaginal tissues. Collagen matrices did not reduce the number of graft-related complications.

Cross-linked xenogenic collagen implantation in the sheep model for vaginal surgery

The properties of meshes used in reconstructive surgery affect the host response and biomechanical characteristics of the grafted tissue. Whereas durable synthetics induce a chronic inflammation, biological grafts are usually considered as more biocompatible. The location of implantation is another determinant of the host response: the vagina is a different environment with specific function and anatomy. Herein, we evaluated a cross-linked acellular collagen matrix (ACM), pretreated by the anti-calcification procedure ADAPT® in a sheep model for vaginal surgery. Ten sheep were implanted with a cross-linked ACM, and six controls were implanted with a polypropylene (PP; 56 g/m²) control. One implant was inserted in the lower rectovaginal septum, and one was used for abdominal wall defect reconstruction. Grafts were removed after 180 days; all graft-related complications were recorded, and explants underwent bi-axial tensiometry and contractility testing. Half of ACM-implanted animals had palpable induration in the vaginal implantation area, two of these also on the abdominal implant. One animal had a vaginal exposure. Vaginal ACMs were 63 % less stiff compared to abdominal ACM explants (p = 0.01) but comparable to vaginal PP explants. Seven anterior vaginal ACM explants showed areas of graft degradation on histology. There was no overall difference in vaginal contractility. Considering histologic degradation in the anterior vaginal implant as representative for the host, posterior ACM explants of animals with degradation had a 60 % reduced contractility as compared to PP (p = 0.048). Three abdominal implants showed histologic degradation; those were more compliant than non-degraded implants. Vaginal implantation with ACM was associated with graft-related complications (GRCs) and biomechanical properties comparable to PP. Partially degraded ACM had a decreased vaginal contractility.

Localized retroperitoneal Castleman's disease: a case report and review of the literature

Introduction

Castleman’s disease, also known as angiofollicular lymph node hyperplasia, is a rare disease with two known expansion types, unicentric and multicentric, which play a major role in determining therapy. We focus here on the unicentric type, which can be treated and cured by surgery. To date, approximately 1000 cases of Castleman’s disease have been reported in the literature.

Case presentation

A 50-year-old Caucasian woman presented to our Department of Hematology and Internal Oncology with increasing fatigue as her sole symptom. Diagnostic investigations including laboratory studies, ultrasound, computed tomography and magnetic resonance imaging were performed. These revealed an interaortocaval, retroperitoneal tumor mass in her upper abdomen as the only manifestation of the disease. No enlarged lymph nodes were detected. We conducted a laparotomy with radical extirpation of the tumor mass (10×9×5.7cm). Complete tumor resection with clear margins was achieved. A pathological analysis of the resected sample showed atypical lymphoid tissue of small to medium cells with some clearly visible nucleoli, enlarged sinusoidal vessels, pleomorphic calcifications and focally preserved germinal-center-like structures. Histological and immunohistochemical analysis confirmed the diagnosis of Castleman’s disease: staining for CD3, CD5, CD10, CD20, CD23, CD79 and Ki-67 was strongly positive in the germinal-center-like structures. Histological findings clearly showed the disease to be the hyaline vascular subtype. Staining for cyclin D1 and CD30 was negative. Expression of CD15 was positive in the enlarged sinusoidal vessels. A supplementary clonality analysis was without pathological findings. Tests for human immunodeficiency virus and human herpes virus 8 were negative and results from a bone marrow biopsy were normal. Our patient recovered well from surgery and was discharged from our hospital. To date, no recurrence of the disease has been detected.

Conclusion

Castleman’s disease is a rare disorder that remains a diagnostic challenge. Radical surgical resection is considered to be the gold standard for treating the unicentric variant of this disease.

Retrieval study at 623 human mesh explants made of polypropylene - impact of mesh class and indication for mesh removal on tissue reaction

Textile meshes frequently are implanted in the abdominal wall to reinforce a hernia repair. However, revisions for mesh associated complications confirm that these devices are not completely free of risk. Explanted devices offer an opportunity to define the impact of mesh structure on tissue response. This retrieval study analyses the tissue reaction to 623 polypropylene mesh samples (170 class 1 with large pores, and 453 class 2 with small pores) explanted for pain, infection, or recurrence. Histopathological assessment included morphometry of inflammatory infiltrate (IF) and connective tissue (CT), and of collagen 1/3 ratio. Half of the meshes were removed after more than 23 month. Despite large inter-individual differences removal for infection showed more IF than for pain or recurrence with significant correlation of IF with CT. Class 1 meshes with large pores showed less IF, CT, fistula formation, calcification, and bridging than class 2 meshes with small pores. Meshes removed for recurrence showed a lowered collagen 1/3 ratio in 70%. Large pore class 1 meshes showed an improved tissue response and may be considered as favorable to prevent inflammatory side effects. The presence of lowered collagen 1/3 ratio in most of the samples with recurrences stresses the relevance of an intact healing process. Late manifestation of complications demands long-lasting follow-up. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.

'The ideal mesh?'

Currently, more than 200 different textile constructions, so-called 'meshes', are available for use world-wide in the more than 20 million operations performed annually for the reinforcement of tissues. As any reintervention at the mesh-tissue compound is a surgical challenge, sometimes resulting in almost untreatable defects, huge efforts are being made to improve the biological and functional performance of the meshes. Based on numerous experimental and clinical studies in the past 20 years, our understanding of them has improved markedly. This includes the biomechanical aspects and the histopathological evaluation of the recipient tissue. Sufficiently large pores as well as structural stability in case of mechanical strain have been identified to be crucial to reduce excessive inflammation and fibrosis. Furthermore, large pores prevent bridging of the foreign body reaction through the pore and thereby help to reduce clinical adverse events as erosion, shrinkage or pain. However, with regard to the many different indications for meshes, there will never be one single ideal mesh for all purposes. To achieve an optimal performance, every construction should be designed according to the specific functional requirements, charging the surgeon to identify the best mesh for his purpose.

IDEAL in meshes for prolapse, urinary incontinence, and hernia repair

PURPOSE

Mesh surgeries are counted among the most frequently applied surgical procedures. Despite global spread of mesh applying surgeries, there is no current systematic analysis of incidence and possible prevention of adverse events after mesh implantation.

MATERIALS AND METHODS

Based on the recommendations of IDEAL an in vitro test system for biocompatibility of surgical meshes has been generated (Innovation). Coating strategies for biocompatibility optimization have been developed (Development). The native and modified alloplastic materials have been tested in an animal model over 2 years (Exploration and Assessment and Long-term study).

RESULTS

In 3 meshes, implanted in sheep and explanted at 4 different time points (a, 3 months; b, 6 months; c, 12 months; and d, 24 months) over 24 months, thickness of inflammatory tissue (TVT a, 35 µm; b, 32 µm; c, 33 µm; d, 28 µm; UltraPro, a, 25 µm; b, 24 µm; c, 21 µm; d, 22 µm; PVDF a, 20 µm; b, 21 µm; c, 14 µm; d, 15µm), connective tissue (TVT a, 37 µm; b, 36 µm; c, 43 µm; d, 41 µm; UltraPro a, 33 µm; b, 32 µm; c, 40 µm; d, 38 µm; PVDF a, 25 µm; b, 22 µm; c, 22 µm; d, 24 µm), and macrophage infiltration (TVT a, 36%; b, 33%; c, 23%; d, 20%; UltraPro a, 34%; b, 28%; c, 25%; d, 22%; PVDF a, 24%; b, 18%; c, 18%; d, 16%) revealed comparable ranking characteristics at every time point after explantation. The in vivo performance of these meshes in a sheep model was predictable with a previously developed in vitro test system. Coating of meshes with autologous plasma prior to implantation seems to have a positive effect on the meshes biocompatibility.

CONCLUSION

We have applied IDEAL criteria on a new innovation for surgical meshes. The results permit the generation of a ranking of currently available meshes with potential to optimize future meshes.

Modified classification of surgical meshes for hernia repair based on the analyses of 1,000 explanted meshes

Background

It is an undisputable fact that meshes have become standard for repair of abdominal wall hernias. Whereas in the late eighties there were only a couple of different devices available, today we have to choose among some hundreds, with lots of minor and major variations in polymer and structure. As most of the minor variations may not lead to significant change in clinical outcome and may be regarded as less relevant, we should focus on major differences. Eventually, this is used to structure the world of mesh by forming groups of textile devices with distinct biological response. Many experimental and some clinical studies have underlined the outstanding importance of porosity, which fortunately, in contrast to other biomechanical quanlities, is widely unaffected by the anisotropy of meshes.

Methods

In accordance with the major manufacturers of meshes, a classification of meshes was derived from a huge pool of textile data based briefly on the following: (1) large pores, (2) small pores, (3) additional features, (4) no pores, (5) 3D structure and (6) biological origin. At 1,000 explanted meshes the value of this classification was evaluated by group-specific assessment of inflammatory and connective tissue reaction.

Results

Application of this classification to common products has proved feasable, and each of the six different classes includes devices that in clinical trials failed to show relevant differences in patients’ outcome when comparing products within the same group. Furthermore, histological analysis confirmed significant differences in tissue reactions between but not within the different classes.

Conclusions

Classifying implants according to a similar response enables grouping patients into comparable cohorts despite implantation of different devices. Furthermore, it enables the examination of the impact of mesh classes for the various indications even from heterogenous data of registries. Finally and not the least, any grouping supports the surgeon to select the best device to meet the individual need and to tailor patients therapy.

Electronic supplementary material

The online version of this article (doi:10.1007/s10029-012-0913-6) contains supplementary material, which is available to authorized users.

Ultrasonic scalpel causes greater depth of soft tissue necrosis compared to monopolar electrocautery at standard power level settings in a pig model

Background

Ultrasonic scalpel (UC) and monopolar electrocautery (ME) are common tools for soft tissue dissection. However, morphological data on the related tissue alteration are discordant. We developed an automatic device for standardized sample excision and compared quality and depth of morphological changes caused by UC and ME in a pig model.

Methods

100 tissue samples (5 × 3 cm) of the abdominal wall were excised in 16 pigs. Excisions were randomly performed manually or by using the self-constructed automatic device at standard power levels (60 W cutting in ME, level 5 in UC) for abdominal surgery. Quality of tissue alteration and depth of coagulation necrosis were examined histopathologically. Device (UC vs. ME) and mode (manually vs. automatic) effects were studied by two-way analysis of variance at a significance level of 5%.

Results

At the investigated power level settings UC and ME induced qualitatively similar coagulation necroses. Mean depth of necrosis was 450.4 ± 457.8 μm for manual UC and 553.5 ± 326.9 μm for automatic UC versus 149.0 ± 74.3 μm for manual ME and 257.6 ± 119.4 μm for automatic ME. Coagulation necrosis was significantly deeper (p < 0.01) when UC was used compared to ME. The mode of excision (manual versus automatic) did not influence the depth of necrosis (p = 0.85). There was no significant interaction between dissection tool and mode of excision (p = 0.93).

Conclusions

Thermal injury caused by UC and ME results in qualitatively similar coagulation necrosis. The depth of necrosis is significantly greater in UC compared to ME at investigated standard power levels.

Overdiagnosis of a typical carcinoid tumor as an adenocarcinoma of the lung: a case report and review of the literature

Background

Overdiagnosis of bronchopulmonary carcinoid tumors together with overtreatment can cause serious postoperative consequences for the patient. We report of a patient with a typical bronchopulmonary carcinoid tumor, which was initially misdiagnosed and treated as an adenocarcinoma of the lung. GnrH receptors and the associated Raf-1/MEK/ERK-1/2-pathway are potential targets for analogs in cancer treatment. We suspected a correlation between the lack of tumor growth, application of leuprolide and the Raf-1/MEK/ERK-1/2-pathway. Therefore, we examined GnrH receptor status in the examined specimen.

Case presentation

In 2010 a 77 year-old male patient was shown to have a tumor mass of about 1.7 cm diameter in the inferior lobe of the left lung. Since 2005, this tumor had hitherto been known and showed no progression in size. The patient suffered from prostate cancer 4 years ago and was treated with TUR-P, radiation therapy and the application of leuprolide. We conducted an explorative thoracotomy with atypical segment resection. The first histological diagnosis was a metastasis of prostate cancer with lymphangiosis carcinomatosa. After several immunohistochemical stainings, the diagnosis was changed to adenocarcinoma of the lung. We conducted a re-thoracotomy with lobectomy and systematic lymphadenectomy 12 days later. The tumor stage was pT1 N0 MX G2 L1 V0 R0. Further immunohistochemical studies were performed. We received the results 15 days after the last operation. The diagnosis was ultimately changed to typical carcinoid tumor without any signs of lymphatic vessel invasion. The patient recovered well from surgery, but still suffers from dyspnea and lack of physical performance. Lung function testing revealed no evidence of impairment.

Conclusion

The use of several immunohistochemical markers, careful evaluation of hematoxylin-eosin sections and the Ki-67 labelling index are important tools in discriminating between carcinoids and other bronchopulmonary carcinomas. Although we could not detect GnrH-receptors in the examined specimen, there may be individual differences in expression. GnrH receptor profiles in typical and atypical carcinoids should be scrutinized. This could lead to new therapeutical options, since the GnrH receptor has already been described on atypical carcinoids. Clinically tested drugs such as leuprolide could come to use.

Evaluation of Biocompatibility of Alloplastic Materials: Development of a Tissue Culture In Vitro Test System

Optimized biocompatibility is a major requirement for alloplastic materials currently applied in surgical approaches for hernia, incontinence, and prolapse situations. Tissue ingrowth/adherence and formation of connective tissue seem to have important influence in mesh incorporation at the implant site. In an in vitro approach we randomly investigated 7 different mesh types currently used in surgeries with various indications with regard to their adherence performance. Using a tissue culture approach, meshes were incubated with tissue representative of fibroblasts, muscle cells, and endothelial cells originating from 10 different patients. After 6 weeks, the meshes were assessed microscopically and a ranking of their adherence performance was established. Tissue culture was successful in 100% of the probes. We did not remark on interindividual differences concerning the growth and adherence performance after incubation with the different meshes in the investigated 10 patients. The ranking was consistent in all patients. In this test system, PVDF Dynamesh® (FEG Textiltechnik, Aachen, Germany) was the mesh with the best growth-in score. The test system was feasible and reproducible. Pore size seems to be a predictor of adherence performance. The test system may be a helpful tool for further investigations, and the predictive value should be assessed in further in vitro and in vivo experiments.

Formation of translational risk score based on correlation coefficients as an alternative to Cox regression models for predicting outcome in patients with NSCLC

Background

Personalised cancer therapy, such as that used for bronchial carcinoma (BC), requires treatment to be adjusted to the patient's status. Individual risk for progression is estimated from clinical and molecular-biological data using translational score systems. Additional molecular information can improve outcome prediction depending on the marker used and the applied algorithm. Two models, one based on regressions and the other on correlations, were used to investigate the effect of combining various items of prognostic information to produce a comprehensive score. This was carried out using correlation coefficients, with options concerning a more plausible selection of variables for modelling, and this is considered better than classical regression analysis.

Methods

Clinical data concerning 63 BC patients were used to investigate the expression pattern of five tumour-associated proteins. Significant impact on survival was determined using log-rank tests. Significant variables were integrated into a Cox regression model and a new variable called integrative score of individual risk (ISIR), based on Spearman's correlations, was obtained.

Results

High tumour stage (TNM) was predictive for poor survival, while CD68 and Gas6 protein expression correlated with a favourable outcome. Cox regression model analysis predicted outcome more accurately than using each variable in isolation, and correctly classified 84% of patients as having a clear risk status. Calculation of the integrated score for an individual risk (ISIR), considering tumour size (T), lymph node status (N), metastasis (M), Gas6 and CD68 identified 82% of patients as having a clear risk status.

Conclusion

Combining protein expression analysis of CD68 and GAS6 with T, N and M, using Cox regression or ISIR, improves prediction. Considering the increasing number of molecular markers, subsequent studies will be required to validate translational algorithms for the prognostic potential to select variables with a high prognostic power; the use of correlations offers improved prediction.

Clinicopathological study of patients requiring reintervention after sacrocolpopexy with xenogenic acellular collagen grafts

PURPOSE

We describe the operative and histopathological findings of patients requiring reintervention because of symptomatic vault prolapse or graft related complications following sacrocolpopexy using xenografts.

MATERIALS AND METHODS

A total of 13 patients underwent secondary sacrocolpopexy because of failure (8) or vaginal revision (5) because of a graft related complication after the initial sacrocolpopexy with porcine dermal collagen (9) or small intestinal submucosa (4). Outcome measures were operative findings and histology of specimens obtained at reintervention. Sections were semiquantitatively scored for the presence of infection, foreign body reaction and fibrosis by a pathologist blinded to the outcome and graft type.

RESULTS

Reinterventions for failure and graft related complications were performed a median of 33 and 15 months, respectively, after the initial operation. Pathology of porcine dermal collagen failures (6) revealed local degradation associated with a minimal foreign body reaction. Porcine dermal collagen remnants were surrounded by minimal fibrosis and neovascularization. Small intestinal submucosa implants of failures (2) were entirely replaced by collagen rich and moderately vascularized connective tissue. Pathology of 3 erosions (all 3 porcine dermal collagen) revealed a locally degraded implant that was surrounded by histiocytes and a polymorphonuclear infiltrate. Pathology of 2 early infections, both small intestinal submucosa, revealed a massive polymorphonuclear infiltration with the implant material remodeled and replaced by loose connective tissue.

CONCLUSIONS

In these clinical recurrences porcine dermal collagen implants were usually locally degraded but still recognizable several years after implantation. Small intestinal submucosa implants were fully replaced by connective tissue. Therefore, the cause of recurrence remains unclear. Porcine dermal collagen erosions displayed features of infection and degradation.

[The "ideal" mesh--more than a mosquito net]

Modern meshes permit a radical treatment of hernias, an expectation that Billroth articulated already more than 100 years ago. Because clinical trials are insufficient to evaluate the distinct effects of modified mesh materials in regard to tissue biocompatibility and functionality, a basic understanding of the physico-chemical properties is essential for a rational selection of the most appropriate device. Experimental data indicate that particularly the mesh's porosity is of outstanding importance, resulting from the demanded tensile strength as well as the employed fibre material. Considering that different operation techniques require different mesh materials, specific requirements are discussed using the example of intraabdominal meshes, of parastomal meshes, of meshes in areas with bacterial contamination and of meshes in the hiatus region. Considering the late manifestation of some complications even after many years, any thorough quality control should include an assessment of explanted implant failures in addition to clinical experience.

Application of zinc-bis-(DL-hydrogensaspartate) does not reduce apoptotic cell death in myocardial infarction in the rat heart

BACKGROUND

Early studies in different stress models have shown potential beneficial effects of exogenous zinc application with reduction in the rate of apoptotic cell death. This has not been shown in models of myocardial infarction.

METHODS

Rats were exposed to either brief episodes of acute ischemia followed by reperfusion (phase 1) or chronic coronary occlusion (phase 2). Animals were either treated with zinc or vehicle. Groups 1 and 3 received zinc-bis-(DL-hydrogenaspartate) 10 mg/kg body weight as a single 5-mL bolus administered intraperitoneally 24 hours prior to coronary occlusion, groups 2 and 4 received saline. The infarct sizes were determined by triphenyltetrazolium chloride staining and expressed at relative areas to areas of ischemia. Histological slices of the rat's myocardium at the border zones of the infarcts were stained with the TUNEL method to assess for apoptosis. Animals in groups 5, 7, and 9 received zinc, given once before and then repeated every 4 days after coronary occlusion, whereas groups 6, 8, and 10 received saline. Animals were observed for observation periods of 13 (groups 9 and 10), 16 (groups 7 and 8), or 19 weeks (groups 5 and 6), respectively. Two-dimensional echocardiography was performed to measure ejection fraction (EF) at baseline and at the end of the observation periods. TUNEL staining was used to detect and quantify apoptosis rate in the border zones of infarcts after the hearts were excised.

RESULTS

Infarct sizes were 49% + 22% in group 1 (zinc + 30 minutes ischemia + 30 minutes reperfusion); 48% + 10% in group 2 (vehicle + 30 minutes ischemia + 30 minutes reperfusion); 42% + 11% in group 3 (zinc + 60 minutes ischemia + 30 minutes reperfusion); and 41% + 23% in group 4 (vehicle + 60 minutes ischemia + 60 minutes reperfusion). In group 1, 11% + 6% of cells were apoptotic compared to 12% + 4% in group 2, 16% + 9% in group 3, and 17% + 7% in group 4 (P > .05). In phase 2, echocardiography revealed a significant reduction in EF in all groups after coronary occlusion. There were no significant differences in EF between the 5 groups at baseline and at follow-up. TUNEL staining did not reveal any significant apoptosis after 13 to 19 weeks.

CONCLUSION

Application of zinc failed to result in reduction of infarct size after temporary coronary occlusion followed by reperfusion and did not demonstrate any reduction in apoptotic cell death. In chronic coronary occlusion, zinc also did not improve EF compared to controls in the presented model in rats. The mechanisms involved in antiapoptotic effects seem to be more complex and might not be inducible by simple zinc injections.

High-frequency oscillatory ventilation reduces lung inflammation: a large-animal 24-h model of respiratory distress

OBJECTIVE

High-frequency oscillatory ventilation (HFOV) may reduce ventilator-induced lung injury in experimental neonatal respiratory distress. However, these data permit no conclusions for large animals or adult patients with acute respiratory distress syndrome (ARDS), because in neonates higher frequencies and lower amplitudes can be used, resulting in lower tidal volumes (VT) and airway pressures. The aim of this study was to compare gas exchange, lung histopathology and inflammatory cytokine expression during lung-protective pressure-controlled ventilation (PCV) and HFOV in a long-term large-animal model of ARDS.

DESIGN

Prospective, randomized, controlled pilot study.

SETTING

University animal laboratory.

SUBJECTS

Sixteen female pigs (55.3 +/- 3.9 kg).

INTERVENTIONS

After induction of ARDS by repeated lavage, the animals were randomly assigned to PCV (VT = 6 ml/kg) and HFOV (6 Hz). After lung injury, a standardised lung recruitment was performed in both groups, and ventilation was continued for 24 h.

MEASUREMENTS AND RESULTS

After lung recruitment sustained improvements in the oxygenation index were observed in both groups. The mean airway pressure (mPaw) was significantly lower in the HFOV group during the experiment (p < 0.01). Histologically, lung inflammation was significantly ameliorated in the HFOV group (p < 0.05). The messenger RNA expression of IL-1-beta in lung tissue was significantly lower in the HFOV-treated animals (p < 0.01).

CONCLUSIONS

These data suggest that HFOV compared with conventional lung-protective ventilation can reduce lung inflammation in a large-animal 24-h model of ARDS. Furthermore, it was shown that lung recruitment leads to sustained improvements in gas exchange with a significantly lower mPaw when HFOV is used.

[Metastasis of medullary plasmocytoma as the cause of acute cholecystitis]

HISTORY AND ADMISSION FINDINGS

A 66-year-old man was found to have a medullary plasmocytoma the year before admission, after sustaining a pathological fracture of the femur. During treatment for sciatica his general condition deteriorated and he developed abdominal pain. Laboratory tests suggested a septic process.

INVESTIGATIONS

The clinical and sonographic findings and computed tomography suggested an acute cholecystitis.

TREATMENT AND COURSE

A cholecystectomy was performed. Microscopic examination revealed metastatic infiltration of the gall bladder by a medullary plasmocytoma.

CONCLUSION

Secondary tumours of the gallbladder considered are thought to be rare. Since 1863 only 95 cases have been reported. The case discussed here is only the second one in which the metastatic tumor was a medullary plasmocytoma. But a search for published and confirmed cases indicates that secondary tumors of the gall bladder are not so rare. Metastatic tumors of the gall bladder should be kept in mind in the differential diagnosis of acute cholecystitis, especially in patients with an advanced primary tumor.

Biomaterial-dependent MMP-2 expression in fibroblasts from patients with recurrent incisional hernias

With regard to the pathogenesis of recurrent incisional hernia, an impaired connective tissue quality leading to an aberrant scarring process has been proposed. For the matrix metalloproteinase (MMP-2) a pathogenetic involvement in direct inguinal hernia development is reported. With mesh implantation as the gold standard treatment for incisional hernias, the aim of the present study was to investigate the MMP-2 expression in patients with recurrent incisional hernias with and without mesh-materials. In primary fibroblast cultures obtained from skin scars in patients with and without recurrent incisional hernias, MMP-2 synthesis and gene expression were investigated. Furthermore, MMP-2 synthesis and gene expression of fibroblasts were compared after incubation with two different mesh materials: polypropylene and absorbable polyglactin filaments. MMP-2 enzyme activity was determined by semiquantitative zymography and mRNA synthesis by quantitative RT-PCR. Both MMP-2 enzyme activity and mRNA expression were similar in hernia and control fibroblasts in vitro. In control fibroblasts mesh incubation did not significantly affect MMP-2 expression, whereas polypropylene mesh contact of fibroblasts from patients with recurrent incisional hernias led to a major decrease of MMP-2 activity and of mRNA expression. In the absence of biomaterials fibroblasts from recurrent incisional hernia, patients have no alterations of their MMP-2 synthesis compared to control fibroblasts, whereas a specific response was found after biomaterial contact hereby indicating differences in fibroblast phenotype.

The lightweight and large porous mesh concept for hernia repair

In modern hernia surgery, there are two competing mesh concepts which often lead to controversial discussions, on the one hand the heavyweight small porous model and on the other, the lightweight large porous hypothesis. The present review illustrates the rationale of both mesh concepts and compares experimental data with the first clinical data available. In summary, the lightweight large porous mesh philosophy takes into consideration all of the recent data regarding physiology and mechanics of the abdominal wall and inguinal region. Furthermore, the new mesh concept reveals an optimized foreign body reaction based on reduced amounts of mesh material and, in particular, a significantly decreased surface area in contact with the recipient host tissues by the large porous model. Finally, recent data demonstrate that alterations in the extracellular matrix of hernia patients play a crucial role in the development of hernia recurrence. In particular, long-term recurrences months or years after surgery and implantation of mesh can be explained by the extracellular matrix hypothesis. However, if the altered extracellular matrix proves to be the weak area, the decisive question is whether the amount of material as well as mechanical and tensile strength of the surgical mesh are really of significant importance for the development of recurrent hernia. All experimental evidence and first clinical data indicate the superiority of the lightweight large porous mesh concept with regard to a reduced number of long-term complications and particularly, increased comfort and quality of life after hernia repair.

Influence of polyglecaprone 25 (Monocryl) supplementation on the biocompatibility of a polypropylene mesh for hernia repair

BACKGROUND

Supplementary polyglecaprone 25 (Monocryl) monofilaments were added to a lightweight pure monofilament polypropylene mesh (PP mesh) to improve intraoperative handling (PP+M mesh). This study was designed to evaluate the influence of this additional supplementation on the biocompatibility in a rodent animal model.

METHODS

Two mesh materials, a composite mesh (PP+M) and the pure polypropylene variant (PP), were compared after subcutaneous implantation in a standardized rat model. Histological analysis of the inflammatory response was performed after 28, 56 and 84 days of implantation. Material absorption, inflammatory tissue reaction, fibrosis and granuloma formation were investigated, as well as the percentage of proliferating and apoptotic cells at the interface.

RESULTS

Both mesh materials showed a slight foreign body reaction involving mainly macrophages and foreign body giant cells. Total absorption of the Monocryl filaments of the PP+M mesh occurred between 56 and 84 days of implantation. Both the inflammatory and the fibrotic reaction were decreased (n.s.) in the PP+M mesh group compared to the pure PP mesh. Whereas the percentage of proliferating cells showed no significant difference, the rate of apoptotic cells was significantly decreased in the PP+M mesh group over the whole implantation period.

CONCLUSION

Compared to the pure polypropylene mesh, our data confirm that the use of a polypropylene mesh supplemented with absorbable Monocryl filaments is feasible without additional short-term mesh-related complications in the experimental model or negative side effects on biocompatibility.

Missing effects of zinc in a porcine model of recurrent endotoxemia

Background

Chronic human sepsis often is characterised by the compensatory anti-inflammatory response syndrome (CARS). During CARS, anti-inflammatory cytokines depress the inflammatory response leading to secondary and opportunistic infections. Proved in vitro as well as in vivo, zinc's pro-inflammatory effect might overcome this depression.

Methods

We used the model of porcine LPS-induced endotoxemia established by Klosterhalfen et al. 10 pigs were divided into two groups (n = 5). Endotoxemia was induced by recurrent intravenous LPS-application (1.0 μg/kg E. coli WO 111:B4) at hours 0, 5, and 12. At hour 10, each group received an intravenous treatment (group I = saline, group II = 5.0 mg/kg elementary zinc). Monitoring included hemodynamics, blood gas analysis, and the thermal dilution technique for the measurement of extravascular lung water and intrapulmonary shunt. Plasma concentrations of IL-6 and TNF-alpha were measured by ELISA. Morphology included weight of the lungs, width of the alveolar septae, and rate of paracentral liver necrosis.

Results

Zinc's application only trended to partly improve the pulmonary function. Compared to saline, significant differences were very rare. IL-6 and TNF-alpha were predominately measured higher in the zinc group. Again, significance was only reached sporadically. Hemodynamics and morphology revealed no significant differences at all.

Conclusion

The application of zinc in this model of recurrent endotoxemia is feasible and without harmful effects. However, a protection or restoration of clinical relevance is not evident in our setting. The pulmonary function just trends to improve, cytokine liberation is only partly activated, hemodynamics and morphology were not influenced. Further pre-clinical studies have to define zinc's role as a therapeutic tool during CARS.