Interventions to promote the implementation of pressure injury prevention measures in nursing homes: A scoping review

AIMS

To identify studies and the content of the interventions that have facilitated the implementation of pressure injury (PI) prevention measures in nursing home settings.

DESIGN AND METHOD

A scoping review methodology was employed. The author has carried out the following steps successively: Identified this scoping review's questions, retrieved potentially relevant studies, selected relevant studies, charted the data, summarised the results, and consulted with stakeholders from nursing homes in China.

DATA SOURCES

Six electronic databases and three resources of grey literature-PubMed, CINAHL, Web of Science Core Collection, Embase, Cochrane Central Register of Controlled Trials, Psych INFO, Open Grey, MedNar, ProQuest Dissertations, and Theses Full Texts were searched from January 2002 through May 2022.

RESULTS

Forty articles were included, among which the primary interventions were quality improvement, training and education, evidence-based practice, device-assisted PI prophylaxis, nursing protocols, and clinical decision support systems. Twenty-three outcome indicators were summarised in 40 articles, which included 10 outcome indicators, seven process indicators, and six structural indicators. Furthermore, only five articles reported barriers in the process of implementing interventions.

CONCLUSION

The common interventions to promote the implementation of PI prevention measures in nursing homes are quality improvement, training, and education. Relatively limited research has been conducted on evidence-based practice, clinical decision support systems, device-assisted PI prophylaxis, and nursing protocols. In addition, there is a paucity of studies examining the impediments to implementing these measures and devising targeted solutions. Therefore, it is recommended that future studies include analysis and reporting of barriers and facilitators as part of the article to improve the sustainability of the intervention.

IMPACT

This article reminds nursing home managers that they should realise the importance of implementation strategies between the best evidence of PI prevention and clinical practice. Also, this review provides the types, contents, and outcome indicators of these strategies for managers of nursing homes to consider what types of interventions to implement in their organisations.

TRIAL AND PROTOCOL REGISTRATION

The protocol of this scoping review was published as an open-access article in June 2022 (Yang et al., 2022).

Midterm Outcome of Valve Repair for Rheumatic Mitral Stenosis: 6-year Experience in a Single Mid-Volume Cardiac Center

OBJECTIVES

Previous studies have reported satisfactory long-term results of mitral valve (MV) repair for rheumatic mitral disease. However, the effects of this procedure in isolated rheumatic mitral stenosis remain unclear. In addition, protective effects of MV repair on cardiac function have not been verified in rheumatic MV disease. This study retrospectively evaluated early mortality and mid-term results of MV repair for isolated rheumatic mitral stenosis in a mid-volume cardiac centre, and explored the effects of this procedure on cardiac function.

METHODS

Between January 2015 and May 2021, 360 patients with isolated rheumatic mitral stenosis and combined (concomitant) atrial fibrillation (AF) underwent MV repair (100 patients) or MV replacement (260 patients). Perioperative characteristics were compared between the two groups and a regression analysis for early mortality and mid-term left ventricular ejection fraction was conducted. In addition, mid-term survival was compared between the two groups.

RESULTS

Baseline characteristics of the two groups were balanced after matching. Compared with patients in the replacement group, patients with MV repair had a lower occurrence of postoperative hypotension and AF. There was no difference in early mortality or mid-term survival between the two groups. However, MV repair was associated with a higher mid-term left ventricular ejection fraction. During follow-up, four thromboembolic events and four haemorrhagic events occurred in the replacement group. No blood coagulation-related complications occurred in the repair group.

CONCLUSION

Mitral valve repair for isolated rheumatic mitral stenosis and concomitant AF was feasible in a mid-volume cardiac centre, with satisfactory perioperative results and mid-term outcomes. Furthermore, this procedure preserved mid-term left ventricular systolic function.

Global, Regional, and National Burdens of Ischemic Heart Disease Attributable to Smoking From 1990 to 2019

Background This study was conducted to estimate the distribution of and changes in the global disease burden of ischemic heart disease attributable to smoking between 1990 and 2019. Methods and Results Data used in this study come from the GBD 2019 (Global Burden of Disease Study 2019). Age-standardized rates and estimated annual percentage change of age-standardized rates were used to describe this burden and its changing trend. Pearson's correlation coefficient was used to evaluate the correlation between the sociodemographic index and changing trend. From 1990 to 2019, the burden of ischemic heart disease attributable to smoking has shown a downward trend globally; estimated annual percentage changes of age-standardized mortality rates and age-standardized disability-adjusted life-years rates were -2.012 (95% CI, -2.068 to -1.956) and -1.907 (95% CI, -1.975 to -1.838). Nineteen countries experienced an increase in disease burden, and the changes in 17 countries were not statistically significant. In addition, this burden was higher in men and older age groups. Estimated annual percentage change of the age-standardized rates of this burden were negatively correlated with the sociodemographic index. Conclusions Although the burden of ischemic heart disease attributable to smoking has decreased in >80% of countries or regions in the past 30 years, it has remained a significant issue in low- and middle-income countries, particularly among men and elderly populations. Therefore, active tobacco control measures, focusing on key populations, are required to reduce the associated burden of ischemic heart disease, especially in those countries or regions with increasing prevalence and disease burden.

Impact of induction therapy on cytomegalovirus infection and post-transplant outcomes in pediatric heart transplant recipients receiving routine antiviral prophylaxis

OBJECTIVES

Induction therapy has been increasingly used in pediatric heart transplantation. This study evaluated the impact of anti-thymocyte globulin (ATG) versus basiliximab as induction therapy on post-transplant cytomegalovirus (CMV) infection, rejection at 1 year, coronary allograft vasculopathy (CAV), and mortality in pediatric heart transplant recipients receiving antiviral prophylaxis.

RESULTS

Of the 96 patients (age < 18 years) analyzed, 46 (47.9%) patients received basiliximab, and 50 (52.1%) received ATG. Median follow-up was 3.0 (IQR, 1.7-4.9) years with 32.3% reporting CMV infection. The ATG group, as compared with the basiliximab group, had similar incidences of CMV infection (36% vs. 28.3%, p = .418), CMV viremia (22% vs. 19.6%, p = .769), and CMV-positive tissue biopsy (30% vs. 22%, p = .486). The ATG group had lower incidences of rejection at 1 year (16% vs. 36.9%, p = .022) and CAV (4% vs. 23.9%, p = .006) with no difference in mortality (8% vs. 15.2%, p = .343), compared with the basiliximab group. Multivariate analysis showed that induction with ATG was associated with a lower risk of rejection at 1 year (OR, .31; 95% CI, .09-.94; p = .039) with no impact on the incidences of CMV infection (HR, 2.06; 95% CI, .54-7.89; p = .292), CAV (HR, .30; 95% CI, .04-2.58; p = .275), and mortality (HR, .39; 95% CI, .09-1.82; p = .233) compared to basiliximab induction.

DISCUSSION AND CONCLUSIONS

In conclusion, induction with ATG was associated with reduction in risk of rejection at 1 year with no effects on CMV infection, CAV, and mortality in pediatric heart transplant recipients with universal antiviral prophylaxis compared with basiliximab induction therapy.

The diagnostic significance of integrating m6A modification and immune microenvironment features based on bioinformatic investigation in aortic dissection

Purpose

The aim of this study was to investigate the role of m6A modification and the immune microenvironment (IME) features in aortic dissection (AD) and establish a clinical diagnostic model for AD based on m6A and IME factors.

Methods

GSE52093, GSE98770, GSE147026, GSE153434, and GSE107844 datasets were downloaded from the GEO database. The expression of 21 m6A genes including m6A writers, erasers, readers, and immune cell infiltrates was analyzed in AD and healthy samples by differential analysis and ssGSEA method, respectively. Both correlation analyses between m6A genes and immune cells were conducted by Pearson and Spearman analysis. XGboost was used to dissect the major m6A genes with significant influences on AD. AD samples were classified into two subgroups via consensus cluster and principal component analysis (PCA) analysis, respectively. Among each subgroup, paramount IME features were evaluated. Random forest (RF) was used to figure out key genes from AD and healthy shared differentially expressed genes (DEGs) and two AD subgroups after gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Finally, we constructed an AD diagnostic model combining important m6A regulatory genes and assessed its efficacy.

Results

Among 21 m6A genes, WTAP, HNRNPC, and FTO were upregulated in AD samples, while IGF2BP1 was downregulated compared with healthy samples. Immune cell infiltrating analysis revealed that YTHDF1 was positively correlated with γδT cell level, while FTO was negatively correlated with activated CD4+ T cell abundance. FTO and IGF2BP1 were identified to be crucial genes that facilitate AD development according to the XGboost algorithm. Notably, patients with AD could be classified into two subgroups among which 21 m6A gene expression profiles and IME features differ from each other via consensus cluster analysis. The RF identified SYNC and MAPK1IP1L as the crucial genes from common 657 shared common genes in 1,141 DEGs between high and low m6A scores of AD groups. Interestingly, the AD diagnostic model coordinating SYNC and MAPK1IP1L with FTO and IGF2BP1 performed well in distinguishing AD samples.

Conclusion

This study indicated that FTO and IGF2BP1 were involved in the IME of AD. Integrating FTO and IGF2BP1 and MAPK1IP1L key genes in AD with a high m6A level context would provide clues for forthcoming AD diagnosis and therapy.

[68Ga-PSMA-I&T PET/CT for assessment of tumor burden in primary lesions of treatmentnaïve prostate cancer]

OBJECTIVE

To investigate the value of ⁶⁸Ga-labeled prostate specific membrane antigen (PSMA) PET/CT for assessing tumor load in primary lesions for risk stratification and predicting metastasis of newly diagnosed prostate cancer (PCa).

METHODS

We retrospectively analyzed the data of 36 patients (mean age 71.3 ± 8.6 years, range 56 to 89 years) with newly diagnosed PCa undergoing ⁶⁸Ga-PSMA-I&T PET/CT from June 2018 to July 2019. SUVmax and SUVmean of the primary lesions were measured, and the primary PSMA tumor volume (PSMA-TV) and total lesion PSMA (TL-PSMA) were automatically measured and calculated in all the patients. The correlations of primary SUVmax, PSMA-TV, and TL-PSMA with PSA and Gleason score (GS) were analyzed, and SUVmax, PSMA-TV and TL-PSMA of the primary lesions were compared among different PCa subgroups.

RESULTS

SUVmax, PSMA-TV and TL-PSMA of the primary lesions were all correlated with PSA and GS (P < 0.05). PCa subgroup analysis showed that SUVmax, PSMA-TV and TL-PSMA were all significantly higher in patients with PSA >20 ng/mL than in those with PSA ≤20 ng/mL (P < 0.001), and were higher in patients with a GS ≥8 than in those with a GS ≤7 (P < 0.001). PSMA-TV and TL-PSMA were significantly higher in patients with tumor metastasis than in those without metastasis (P < 0.001), while SUVmax did not differ significantly with tumor metastasis. SUVmax (P=0.002), PSMA-TV (P < 0.001), and TL-PSMA (P < 0.001) were all significantly higher in high-risk group than in low-to moderate-risk group.

CONCLUSION

PSMA-TV and TL-PSMA of ⁶⁸Ga-PSMA-I&T PET/CT have potential value in predicting risk stratification and metastasis of newly diagnosed PCa.

Intrinsic left ventricular impairment in Marfan syndrome: A systematic review and meta-analysis

BACKGROUND

Intrinsic cardiac impairment in Marfan syndrome (MFS) has been explored in many clinical studies; however, their results have been inconsistent. This meta-analysis aimed to assess the difference in cardiac structure and function between Marfan patients and healthy individuals, and to verify the hypothesis of intrinsic cardiac impairment in MFS.

METHODS

Electronic searches for studies were performed in the PubMed, Embase, and Cochrane Library databases. Nine studies with 490 patients with MFS and 478 controls were included in the analysis. Age and sex were strictly matched between Marfan patients and healthy controls in every study.

RESULTS

There was no difference in the left ventricular end systolic diameter index (mean difference [MD]: 0.33; 95% confidence interval [CI]: (-0.24, 0.89); p = 0.26) and left ventricular end diastolic diameter index (MD: 0.18; 95% CI: [-0.47, 0.83]; p = 0.58) between Marfan patients and controls. Marfan patients showed larger left ventricular end systolic volume index (MD: 2.62; 95% CI: [0.27, 4.97]; p = 0.03) and left ventricular end diastolic volume index (MD: 4.16; 95% CI: [2.70, 5.63]; p < 0.01) than the control group. Furthermore, Marfan patients showed a lower left ventricular ejection fraction than healthy people (MD: -2.59%; 95% CI: [-4.64%, -0.54%]; p = 0.01).

CONCLUSIONS

Intrinsic cardiac impairment was observed in MFS. MFS patients showed the larger left ventricular volume and poorer left ventricular function than matched controls. Considering the potentially adverse impact on cardiac function, intrinsic cardiac impairment in MFS should be considered during the cardiac surgery.

Effect of bradykinin on rats with thromboangiitis obliterans through PI3K/Akt signaling pathway

OBJECTIVE

To explore the effect of bradykinin on rats with thromboangiitis obliterans (TAO) through the phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/Akt) signaling pathway.

MATERIALS AND METHODS

The female Wistar rats were injected with lauric acid via the femoral artery to establish the TAO model, and they were randomly divided into control group (healthy rats), model group (TAO rats) and bradykinin group (TAO rats injected with bradykinin B2 receptor-specific inhibitor). The control was set in each group before the operation. The level of serum bradykinin in each group was detected via enzyme-linked immunosorbent assay (ELISA), and the reactive oxygen species (ROS) level, Caspase-3 activity and PI3K/Akt protein concentration in vascular tissues were measured via ELISA, Western blotting, ROS assay, and Caspase-3 activity assay, respectively. Moreover, the specific therapeutic mechanism of bradykinin was analyzed.

RESULTS

In control group, the intima of the lower extremity venous tissues was smooth, the extima had no evident changes, and there was no inflammatory cell invasion around the arteries and veins. In model group, there was massive inflammatory cell invasion into the lower extremity venous tissues. In bradykinin group, fibrosis and atrophy occurred in venous tissues, the extima was thickened without fibrosis, and there was phagocytosis of neutrophils and mononuclear macrophages around the arteries and veins, as well as massive inflammatory infiltration. The PI3K/Akt protein concentration in lower extremity venous tissues was the highest in control group and the lowest in bradykinin group, and there were statistically significant differences (p<0.01). At 24 h after administration of doxorubicin (DOX), the level of ROS in lower extremity venous tissues was higher in bradykinin group than that in model group (p<0.05), and it was also higher in model group than that in control group (p<0.05). Besides, the activity of Caspase-3 in lower extremity venous tissues was significantly increased in bradykinin group compared with that in model group and control group, while it was slightly higher in model group than that in control group (p<0.05).

CONCLUSIONS

The low expression of bradykinin can promote TAO in rats by the mechanism that it inhibits the PI3K/Akt signaling pathway to raise the oxidative stress level, thereby aggravating TAO.

Original Research: Adipose-derived stem cells from younger donors, but not aging donors, inspire the host self-healing capability through its secreta

Adipose-derived stem cells demonstrate promising effects in promoting cutaneous wound healing, but the mechanisms are still not well defined and contradictory views are still debatable. In the present research, we established a mouse cutaneous wound model and investigated the effects of adipose-derived stem cells in wound healing. Adipocyte, adipose-derived stem cells, and epidermal keratinocyte stem cells were isolated from younger and aged donors according to the standard protocol. The conditioned medium either from adipose-derived stem cells or from adipocytes was used to treat epidermal keratinocyte cells. The results showed that adipocytes or adipose-derived stem cells isolated from younger donors demonstrated mild advantage over those cells isolated from aging donors. Adipose-derived stem cells showed stronger stimuli than adipocytes, and the adipose-derived stem cells or adipocytes from younger donors enabled to support higher growth rate of keratinocyte stem cells. The invasion of vasculature was observed at day 10 after posttransplantation in the mice bearing the keratinocyte stem cells or combination of keratinocyte stem cells with adipose-derived stem cells; however, simply inoculating keratinocyte stem cells from aging donors did not result in vasculature formation. Adipose-derived stem cells isolated from younger donors were able to inspire the host's self-healing capabilities, and age-associated factors should be taken into consideration when designing a feasible therapeutic treatment for skin regeneration.

The Tumor Suppressive Role of MiRNA-509-5p by Targeting FOXM1 in Non-Small Cell Lung Cancer

BACKGROUND/AIMS

Deregulation of microRNAs (miRNAs) expression is a frequent event in cancer development and progression. Recent studies have implied that abnormal expression of miRNAs is frequently observed in non-small cell lung cancer (NSCLC). Here, we examined the levels and biological functions of miR-509-5p in NSCLC.

METHODS

The levels of miR-509-5p were measured by real-time quantitative PCR (RT-PCR) in NSCLC cell lines and NSCLC tissues along with adjacent normal tissues. Cell viability was analyzed by MTT and colony formation assay. Cell migration and invasion were evaluated by transwell and wound healing assay. In addition, we predicted the putative targets of miR-509-5p by bioinformatics analyses. Moreover, by luciferase-reporter assay, we analyzed the relationship between miR-509-5p and the target in NSCLC cells.

RESULTS

miR-509-5p expression was significantly reduced in NSCLC tissues compared with adjacent normal tissues. In addition, miR-509-5p decreased cell proliferation, migration and invasive capability of NSCLC cells. Moreover, we found that FOXM1 was a putative target of miR-509-5p. Enforced miR-509-5p expression in NSCLC cells reduced both mRNA and protein levels of FOXM1. Furthermore, dual-luciferase reporter assay showed miR-509-5p could bind to the 3' untranslational regions of FOXM1 mRNA. Furthermore, overexpression of FOXM1 reversed cell viability, migration, invasion and vimentin levels suppressed by miR-509-5p mimics in H1299 cells.

CONCLUSIONS

miR-509-5p exerts tumor-suppressive effects by attenuating FOXM1 in NSCLC. Collectively, these findings provide further evidence that miR-509-5p may be considered as a novel and potential target for the diagnosis, prognosis and treatment of NSCLC.

Dose of intravenous steroids and therapy outcome in Graves' orbitopathy

BACKGROUND AND AIM

Several trials have proved the efficacy of intravenous (IV) steroids in Graves' orbitopathy (GO). However, the impact of administered dose and therapy schedule has not been assessed yet.

SUBJECTS AND METHODS

Nine randomized and 14 non-randomized controlled trials of IV steroids in GO were evaluated according to the applied single and cumulative doses with respect to outcome, efficacy on clinically relevant issues and adverse events.

RESULTS

High single (1 g per day) and cumulative (>6 g) doses of IV steroids are superior to lower single (0.5 g/d) and cumulative (<5 g) doses with respect to therapy response (84 vs 75%; p=0.034 and 83 vs 77%; ns, respectively), improvement of eye symptoms (87 vs 75%, p=0.052 and 85 vs 71%; ns, respectively) and disappearance of diplopia (32 vs 27%; ns and 48 vs 27%; p=0.08, respectively). Decrease of both clinical activity score (3 vs 2.5 points and 2.5 vs 3, ns) as well as proptosis (-1.4 vs -1.2 mm, ns and 1.5 vs 1.2, ns) are similar in both groups. However, high single and/or cumulative doses are accompanied with a 2-fold higher rate of adverse events (56 vs 28%; p<0.001 and 52 vs 33%; p=0.034, respectively).

CONCLUSIONS

Tailoring the IV steroid dose to severity of GO can be concluded and implies that a prospective randomized trial comparing different doses of IV steroids in active/severe GO is keenly warranted.

Clinical review: Intravenous glucocorticoids for Graves' orbitopathy: efficacy and morbidity

CONTEXT

The administration of iv glucocorticoid pulses has been advocated as a treatment approach for patients with inflammatory and moderate to severe Graves' orbitopathy (GO). This review offers an update on this controversial regimen.

EVIDENCE ACQUISITION

PubMed and the MeSH-Database were searched (with no temporal limit) for the following topics: management of active and severe GO; glucocorticoid therapy of GO; iv glucocorticoid administration; mechanism and pharmacokinetics of iv glucocorticoids; and adverse events, morbidity, and mortality of iv glucocorticoids. The articles were evaluated according to their setting and study design.

EVIDENCE SYNTHESIS

All randomized and uncontrolled trials, consensus statement, systematic reviews, and meta-analyses dealing with the efficacy and morbidity of iv glucocorticoids in GO were identified.

CONCLUSIONS

The current first-line treatment for active, moderate-to-severe GO is a 12-wk course of high-dose iv glucocorticoid pulses. The response rate of this regimen is approximately 80%. Intravenous glucocorticoids have a statistically significant advantage over oral treatment and cause significantly fewer adverse events. However, major side effects related to preexisting diseases, administered dose, and treatment schedule have been reported. The morbidity and mortality of iv glucocorticoid therapy are 6.5 and 0.6%, respectively. Thus, careful patient selection is warranted. Before iv glucocorticoid administration, patients should be screened for recent hepatitis, liver dysfunction, cardiovascular morbidity, severe hypertension, inadequately managed diabetes, and glaucoma. The cumulative dose should not exceed 8 g, and with the exception of sight-threatening GO the single doses preferably should not be administered on consecutive days. Monthly monitoring during subsequent treatment is warranted.

A study on Notch signaling in human breast cancer

Breast cancer is one of the leading causes of cancer death in women. The Notch family of proteins plays crucial roles in determining cell fates such as proliferation, differentiation and apoptosis. A role for Notch signaling in human breast cancer has been suggested by the development of adenocarcinomas in the murine mammary gland. However, it is not clear currently whether Notch signaling is frequently expressed and activated in breast cancers. Here we show that Notch signaling is overexpressed and highly activated in breast cancers. More significantly, the attenuation of Notch signaling by gamma-secretase inhibitor can inhibit the proliferation of breast cancer cells by both causing cell cycle arrest and apoptosis. Thus, targeting Notch signaling may be of therapeutic value in breast cancers.

In vivo staphylococcal superantigen-driven polyclonal Ig responses in mice: dependence upon CD4(+) cells and human MHC class II

Staphylococcal enterotoxin (SE) B and seven other staphylococcal superantigens (SAg), despite promoting vigorous Ig production in human peripheral blood mononuclear cell cultures, are exceedingly poor at eliciting Ig responses in cultures of spleen cells from C57BL/10J (B10) or C3H/HeJ mice. In contrast, SEB elicits Ig responses in cultures of spleen cells from human MHC class II-transgenic mice. Whereas i.p. administration of SEB (0.2-20 microg) to non-transgenic B10 mice elicits very weak in vivo Ig responses, identical treatment of CD4(+) cell-intact (but not CD4(+) cell-depleted) human MHC class II-transgenic mice elicits dramatic increases in both splenic Ig-secreting cells and serum Ig levels. Over a 2-week period, the SEB-induced in vivo Ig responses peak and then plateau or fall in association with a preferential increase in splenic CD8(+) cells. Nevertheless, in vivo depletion of CD8(+) cells has no sustained effect on SEB-driven Ig responses. Taken together, these observations demonstrate that the effects of SAg on in vivo humoral immune responses are highly CD4(+) cell dependent, are substantially CD8(+) cell independent and can be successfully investigated using human MHC class II-transgenic mice. This model system may be useful in investigating the polyclonally activating effects of microbial products (prototypic environmental insults) on the development of systemic autoimmunity.

Comparative effects of etomidate, ketamine, propofol, and fentanyl on myocardial contractility in dogs

PURPOSE

The present study was carried out to determine the direct effects of etomidate, ketamine, propofol, and fentanyl on myocardial contractility, and whether fentanyl would enhance the myocardial depression caused by propofol.

METHOD

The anesthetics were injected directly into the circuit that supplied blood to the left circumflex coronary artery (LCX) in anesthetized open-chest dogs. Myocardial contractility was evaluated from measurements of percent segmental shortening (%SS).

RESULTS

Etomidate, ketamine, and propofol significantly reduced %SS in a dose-dependent manner. The %SS values with 1.6 and 3.2 mg of etomidate were similar to those with 3.2 and 6.4 mg of ketamine, respectively, and the %SS value with 6.4 mg of propofol was similar to those with 3.2 and 6.4 mg of ketamine. Fentanyl alone had no effects on myocardial performance and did not influence the effect of propofol on %SS.

CONCLUSION

On the basis of clinical doses, the direct myocardial depressant effect of ketamine is more than twice as potent as that of etomidate and slightly more than that of propofol. Fentanyl has no inotropic effect and does not enhance the direct myocardial depressant effect of propofol.

Influence of micro-organisms on the dissolution of metallic platinum emitted by automobile catalytic converters

Platinum emitted by automotive catalyst converters mainly exists in the metallic form, which is not bioavailable. Several investigations showed that finely dispersed metallic platinum is dissolved in organic matrices to a significantly high degree. In an exclusion experiment, observations were made as to whether the transformation of Pt(0) and other platinum compounds is mainly of a chemical nature or is influenced by micro-organisms. A previous experiment, concerning the interaction of several platinum compounds with a clay-like humic soil was repeated under sterile conditions to rule out the influence of micro-organisms. During the time of interaction (3-60 d), no significant differences were observed between the sterile and non-sterile modes. Thus, the dissolution of metallic platinum into soluble species, observed previously within this time period, seems to be mainly of a chemical nature.