Complications and pitfalls of endovenous laser therapy for varicose veins of lower extremities.

Varicose veins of lower extremities are a common disorder affecting a significant proportion of adult population. Endovenous techniques have been used in clinical practice for more than 20 years for their radical treatment; of these, laser therapy is one of the most widely utilized options. However, this treatment modality, too, has its specific side effects and complications which can be divided into perioperative (difficult venous access, fiber or sheath damage, vasovagal reaction with a drop in blood pressure and bradycardia, cutaneous thermal injury), and postoperative (bruising and hematomas, exceptionally pain, superficial venous thrombosis (phlebitis) and fibrous cord formation or pigmentations). Paresthesias, infections, arteriovenous fistulas, deep venous thrombosis and pulmonary embolism are very rare. The introduction of new generators with higher wavelengths and fibers with radial emission of laser energy has substantially reduced the side effects and complications. Performing the surgery in the outpatient setting using tumescent local anesthesia and under perioperative ultrasound control is an essential condition of the procedure.

Mobile App for Simplifying Life With Diabetes: Technical Description and Usability Study of GlucoMan.

BACKGROUND: Patients with diabetes can be affected by several comorbidities that require immediate action when occurring as they may otherwise cause fatal or consequential damage. For this reason, patients must closely monitor their metabolism and inject insulin when necessary. The documentation of glucose values and other relevant measurements is often still on paper in a diabetes diary. OBJECTIVE: The goal of this work is to develop and implement a novel mobile health system for the secure collection of relevant data referring to a person's metabolis and to digitize the diabetes diary to enable continuous monitoring for both patients and treating physicians. One specific subgoal is to enable data transmission of health parameters to secure data storage. METHODS: The process of implementing the system consists of (1) requirements analysis with patients and physicians to identify patient needs and specify relevant functionalities, (2) design and development of the app and the data transmission, and (3) usability study. RESULTS: We developed and implemented the mobile app GlucoMan to support data collection pertaining to a person's metabolism. An automated transfer of measured values from a glucometer was implemented. Medication and nutrition data could be entered using product barcodes. Relevant background knowledge such as information on carbohydrates was collected from existing databases. The recorded data was transmitted using international interoperability standards to the MIDATA.coop storage platform. The usability study revealed some design issues that needs to be solved, but in principle, the study results show that the app is easy to use and provides useful features. CONCLUSIONS: Data collection on a patient's metabolism can be supported with a multifunctional app such as GlucoMan. Besides monitoring, continuous data can be documented and made available to the treating physician. GlucoMan allows patients to monitor disease-relevant parameters and decide who accesses their health data. In this way, patients are empowered not only to manage diabetes but also manage their health data.

Economically Efficient Hepatitis C Virus Treatment Prioritization Improves Health Outcomes.

BACKGROUND: The total cost of treating the 3 million Americans chronically infected with hepatitis C virus (HCV) represents a substantial affordability challenge requiring treatment prioritization. This study compares the health and economic outcomes of alternative treatment prioritization schedules. METHODS: We developed a multiyear HCV treatment budget allocation model to evaluate the tradeoffs of 7 prioritization strategies. We used optimization to identify the priority schedule that maximizes population net monetary benefit (NMB). We compared prioritization schedules in terms of the number of individuals treated, the number of individuals who progress to end-stage liver disease (ESLD), and population total quality-adjusted life years (QALYs). We applied the model to the population of treatment-naive patients with a total annual HCV treatment budget of US$8.6 billion. RESULTS: First-come, first-served (FCFS) treats the fewest people with advanced fibrosis, prevents the fewest cases of ESLD, and gains the fewest QALYs. A schedule developed from optimizing population NMB prioritizes treatment in the first year to patients with moderate to severe fibrosis who are younger than 65 years, followed by older individuals with moderate to severe fibrosis. While this strategy yields the greatest population QALYs, prioritization by disease severity alone prevents more cases of ESLD. Sensitivity analysis indicated that the differences between prioritization schedules are greater when the budget is smaller. A 10% annual treatment price reduction enabled treatment 1 year sooner to several patient subgroups, specifically older patients and those with less severe liver fibrosis. CONCLUSION: In the absence of a sufficient budget to treat all patients, explicit prioritization targeting younger people with more severe disease first provides the greatest health benefits. We provide our spreadsheet model so that decision makers can compare health tradeoffs of different budget levels and various prioritization strategies with inputs tailored to their population.

The cytoskeletal protein LASP-1 differentially regulates migratory activities of choriocarcinoma cells.

PURPOSE: During healthy pregnancy, a distinct but limited invasion of trophoblast cells into the uterus occurs. In contrast, excessive trophoblast invasion is associated with placental choriocarcinoma (CC). Overexpression of the cytoskeletal protein LASP-1 was shown to contribute to cancer aggressiveness. Here, the yet unknown role of LASP-1 in CC cells is analysed. METHODS: Expression of LASP-1 in human primary carcinoma was assessed by immunohistochemistry and confirmed in CC-derived cell lines by immunocytochemistry, RT-PCR and Western blot. After down-regulation of LASP-1 expression with specific si-RNA in CC-derived cell lines, migratory and proliferative activities were analysed by matrigel migration assay and WST-8 test. RESULTS: LASP-1 expression was detected in human primary choriocarcinoma and in JEG-3, JAR and BeWo cells. Knock down of LASP-1 resulted in a decreased expression of LASP-1 protein in JEG-3 and JAR cells accompanied by a diminished migration and a decreased proliferative activity of these two cell lines. Knockdown of LASP-1 in BeWo cells failed. In consequence, migratory function and proliferation was unaffected. CONCLUSION: This is the first study describing LASP-1 expression in CC cells. Detecting an affection of migratory processes after LASP-1 silencing, we propose that LASP-1 could impact on metastasis of CC cells.

Quantitative mapping of glycoprotein micro-heterogeneity and macro-heterogeneity: an evaluation of mass spectrometry signal strengths using synthetic peptides and glycopeptides.

Mass spectrometry has made possible the field of proteomics and become an invaluable tool for identifying and quantifying post-translational modifications of proteins from complex mixtures. Because PTMs are recognized as key factors of biological activity, reliable PTM characterization is essential to understanding the relationship between protein isoform and activity. Protein glycosylations, in particular, can be especially difficult to characterize due to the range of different oligosaccharide entities that may be attached at any particular site. In this month' Special Feature Dr Daniel Kolarich of the Dept. of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces and his collaborators point out that quantitative label-free glycoproteomics can yield information about glycoprotein microand macroheterogeniety if the tools are sufficiently accurate. To understand and characterize the performance capability of MS tools they synthesized a panel of peptides and their glycopeptide derivatives as references and used these to investigate the qualitative and quantitative results from various ionization techniques and mass analyzers.

Multi-site voxel-based morphometry--not quite there yet.

Voxel-based morphometry (VBM) is a widely applied method in computational neurosciences but it is currently recommended to compare only data collected at a single MRI scanner. Multi-site VBM would be a desirable approach to increase group size and, thus, statistical power. We aimed to assess if multi-site VBM is feasible on similar hardware and compare the magnitude of inter- and intra-scanner differences. 18 healthy subjects were scanned in two identical 3T MRI scanners using different head coil designs, twice in scanner A and once in scanner B. 3D T1-weighted images were processed with SPM8 and FSL4.1 and compared as paired t-test (scan versus re-scan) on a voxel basis by means of a general linear model (GLM). Additionally, coefficient-of-difference (coeffD) maps were calculated for respective pairs of gray matter segmentations. We found considerable inter-scanner differences clearly exceeding a commonly used GLM significance threshold of p<0.05 (FWE corrected). The spatial pattern of detected differences was dependent on whether SPM8 or FSL4.1 was used. The inclusion of global correcting factors either aggravated (SPM8) or reduced the GLM detected differences (FSL4.1). The coeffD analysis revealed markedly higher variability within the FSL4.1 stream both for the inter- and the intra-scanner comparison. A lowered bias cutoff (30 mm FWHM) in SPM8 improved the comparability for cortical areas. Intra-scanner scan/re-scan differences were generally weaker and did not exceed a p<0.05 (FWE corrected) threshold in the GLM analysis. At 3T profound inter-scanner differences are to be expected that could severely confound an unbalanced VBM analysis. These are like related to the receive bias of the radio-frequency hardware.

Recent progress in liquid chromatography-based separation and label-free quantitative plant proteomics.

Recent innovations in liquid chromatography-mass spectrometry (LC-MS)-based methods have facilitated quantitative and functional proteomic analyses of large numbers of proteins derived from complex samples without any need for protein or peptide labelling. Regardless of its great potential, the application of these proteomics techniques to plant science started only recently. Here we present an overview of label-free quantitative proteomics features and their employment for analysing plants. Recent methods used for quantitative protein analyses by MS techniques are summarized and major challenges associated with label-free LC-MS-based approaches, including sample preparation, peptide separation, quantification and kinetic studies, are discussed. Database search algorithms and specific aspects regarding protein identification of non-sequenced organisms are also addressed. So far, label-free LC-MS in plant science has been used to establish cellular or subcellular proteome maps, characterize plant-pathogen interactions or stress defence reactions, and for profiling protein patterns during developmental processes. Improvements in both, analytical platforms (separation technology and bioinformatics/statistical analysis) and high throughput nucleotide sequencing technologies will enhance the power of this method.

[Veins and diabetes]. / Flebologické problémy a diabetes.

Patients with trophic ulcers of lower extremities are relatively frequently diagnosed with diabetes mellitus with venous aetiology being the cause of these defects in up to 70% of patients. Chronic venous insufficiency most frequently results from primary venous insufficiency (mostly lower limb varices) or occurs secondarily as a result of deep vein thrombosis. Lower limb varices are common in human population; they affect 20-25% of women and 10-15% of men, and the incidence increases with age. With respect to radicality of treatment approaches, surgical management is unequivocally considered as the most effective. Apart from the traditional open surgery, clinical practice of the recent years has seen the advance of mini-invasive endovascular methods to treat varices of the main (stem) veins--radiofrequency and laser thermocoagulation. The main principle behind radiofrequency ablation is thermocoagulation of insufficient saphenous vein by bipolar radiofrequency current; endovenous laser uses, for the same purpose, energy of a beam of light. Both methods inactivate the insufficient veins while leaving them in the patient body. Thermal damage of the pathological venous wall leads to contraction and obliteration of the vein and, gradually, to its full resorption. Apart from minimizing recurrence, the technique is also valuable with respect to its cosmetic effect and gentleness of the procedure, allowing fast return to full activity. Studies comparing endovascular interventions with the traditional surgeries confirmed that radiofrequency or laser techniques are safe and well tolerated with the outcomes fully comparable to open surgery in its modern form.

[The complication of a periproctal abscess--Fournièr's gangrene or necrotizing fasciitis? A case report]. / Komplikace periproktálního abscesu--Fournièrova gangréna nebo nekrotizující fasciitida? Kazuistika.

INTRODUCTION: Periproctal abscess is a routine diagnosis of everyday surgical practice. Fournièr's gangrene with progress to the sepsis is one of the most serious complication of this disease. CASE REPORT: The authors present a case review of fulminant surgical infection run as a Fournièr's gangrene and a necrotizig fasciitis of a right lower limb and body with the progress of severe septic status, which started on the strength of a contusion with formation of a periproctal absceding haematoma. A patienthood led to the long-term intensive care with a necessity of multiple surgeries and with subsequent rehabilitative care. This case is rare by the origin of thus extensive infection of soft tissue and its illustration of the heftiness of the patient's treatment with such a disease. CONCLUSION: Fournièr's gangrene and necrotizing fasciitis are loaded by a high-grade of mortality. It is one of the most serious surgical infection, which ends by death frequently. The therapy is primarily surgical, but it cannot be sufficient without aggressive intensive care of a patient.

[A six-year experience with endovenous laser in the treatment of lower extremity varices]. / Sest let zkuseností s endovenózním laserem v terapii varixu dolních kon etin.

AIMS: Endovascular techniques of saphenous ablation are the miniinvasive alternatives of the radical surgical treatment. This study summarizes our own clinical experience with endovenous laser. MATERIAL AND METHODS: During 6 year period we performed in total 723 endovenous laser procedures of trunk varicose veins of lower extremities in 630 patients. Every patient was preoperatively examined clinically and with color duplex machine. Primary varicose veins were operated on in 664 cases, in 59 cases the procedure was performed in recurrent varicose veins with reflux in the residual saphenous trunk. Post-operative follow-up (clinical and duplex ultrasound) was performed after 5 days and 1 month, 6 months and yearly thereafter. The results were evaluated by comparison of CEAP clinical class and quality of life (QoL) pre- and post-operatively, by the percentage of recanalizations and also using Kaplan-Meier life-table method. RESULTS: No thrombosis, nor pulmonary embolism were diagnosed in the post-operative period; from the whole cohort of 723 laser procedures, the postoperative data were available during different time periods in 718 cases (99.3%). Saphenous occlusion was verified in 97.3% after 1 month, non-occlusion or early reopening was seen in 2.7%. In total, 44 non-occluded trunk veins were found during the whole follow-up period (1-72 months, mean 15 months) which represents the final occlusion result of 93.9%. With stronger Kaplan-Meier analysis, we reached 88.9% occlusion rate during the follow-up period of 6 years. Cox regression analysis of factors influencing non-occlusion and early or late recanalisation of saphenous vein found 2 factors with statistical importance: energy per centimeter of vein length (p = 0.04) and laser power (p = 0.04). Cumulative rate of occlusions in 72 months horizon is significantly higher (94%) in patients treated with more than 50 J/cm compared to less than 50 J/cm (87%), log-rank test 0.039. When comparing the influence of laser power on the quality of saphenous occlusion, the treshold of 13W was set arbitrary based on median values in occluded and non-occluded cohorts and using the Kaplan-Meier survival method, the results of the treatment with power less than 13W and more than 13W were analysed. Using the power values less than 13W, the results were significantly better (p = 0.031) compared to power values of 13 W or more. Mean clinical CEAP classification improved from 2.22 (before operation) to 0.24 (1 month after) and 0.48 (last visit) and also QoL was significantly better in laser group compared to traditional surgery group (p < 0.001). The sick leave was also significantly shorter in the laser group ( median 0 days) compared to traditional group (median 40 days), p < 0.01. CONCLUSIONS: The results of endovenous laser ablation of varicose veins depend mainly on meticulous pre-operative ultrasound examination and sufficient technical parameters of the therapy. The present study supports the concept of "slow heating" during the endovenous laser treatment of varicose veins to achieve sufficient energy per centimetre of the vein and the optimal clinical outcome.

[Crossectomy doesn't improve outcome of endovenous laser ablation of varicose veins]. / Krossektomie nezlepsuje výsledky endovenózní laserové lécby varixu.

AIMS: Crossectomy (extended saphenofemoral or saphenopopliteal junction ligation) and stripping of refluxing saphenous trunk represent the basis of the traditional surgical therapy of varicose veins. Endovascular techniques of saphenous ablation are the mini-invasive alternatives of the radical surgical treatment. The objective of this study is the comparison of the endovenous laser ablation with and without crossectomy through open groin access. MATERIAL AND METHODS: Retroprospective study compares the results of the group of patients treated with simple endovenous laser ablation (HVL - 329 limbs) and HVL completed with crossectomy (35 limbs). Both groups were comparable in terms of basic demographic and preoperative clinical data (p > 0.05). In both cohorts, subgroups with identical laser parameters were selected (p > 0.05). All procedures were performed according the same standard protocol, EVL patients received LMWH in the postoperative period. The results were evaluated by the comparison of CEAP clinical class pre and postoperatively, the percentage of recanalizations and also using the Kaplan-Meier life-table method. RESULTS: No thrombosis, nor pulmonary embolism were diagnosed in the post-operative period. During the follow-up (98% treated limbs), venous occlusion was observed in 88% of them (91.05 % in the endovenous group and 65.71% in the combined group). These differences are not statistically significant (p = 0.24). Same results were found using the Kaplan-Meier method (p = 0.086). Treatment significantly reduced CEAP clinical class in both groups but the results are better (C = 0.41 vs. 0.8) in the endovenous group (p = 0.004). CONCLUSIONS: Endovenous ablation of the refluxing saphenous vein represents good alternative of crossectomy and stripping. Combination of both procedures is not effective and, on the contrary, can cause short and long-term complications.

Standardisation of parameters during endovenous laser therapy of truncal varicose veins--experimental ex-vivo study.

BACKGROUND: Vein shrinkage is a surrogate marker for successful laser treatment of varicose veins. However, many controversies still remain concerning the best laser parameters to use. The aim of this study was standardisation of intraoperative energy dosages and pull-back rates to achieve optimal clinical results. DESIGN: Ex-vivo study in surgically removed saphenous trunks. MATERIAL AND METHODS: Great saphenous veins were removed by Babcock stripping and irradiated with laser energy delivered by a laser diode emitting at 980 nm. In total, 279 vein segments (5 cm long) were treated using powers from 5-15 W. Vein segments were opened longitudinally and the circumference measured in the treated and untreated regions to assess thermal shrinkage. RESULTS: The greatest shrinkage and minimum number of perforations was achieved using lower or medium power (8 to 12 W) with longer exposure to administer laser energy. The median percentage vein shrinkage was 50% (power 5 W), 45% (8 W), 40% (10 W), 45% (12 W) and 59% (15 W). When a higher power was used (15 W), the perforations were more frequent and carbonisation was marked. CONCLUSIONS: Our data suggests that similar efficacy with fewer vein perforations may be obtained with low or medium power settings and increased exposure when undertaking laser obliteration of saphenous trunks. This may result in fewer adverse events such as ecchymosis following treatment in patients.

[Endovenous laser photocoagulation of the insufficient saphenous vein in experiment]. / Endovenózní laserová fotokoagulace insuficientní safény v experimentu.

AIMS: The endovenous laser treatment of varicose veins has been using for several years throughout the world with clinical results comparable to traditional surgery. Nevertheless, many controversies still exist in the world literature in terms of parameters of laser generator and procedure itself. The aim of this laboratory study was the standardisation of the procedure and set-up of the optimal technical parameters to achieve maximal vein shrinkage as basic marker of successful long-term result. MATERIAL AND METHODS: The insufficient trunks of the long saphenous veins which were stripped during the traditional Babcock's stripping procedure, were irradiated with the laser energy delivered by the diode generator emitting 980 nm laser beam in the laboratory settings. In total, 279 vein segments were treated. We used the power of 5W, 8W, 10W, 12W and 15W during the maximal time possible to achieve the maximal shrinkage of the saphenous vein with minimal number of perforations. The study cohort consisted of two groups -in the first group the veins were filled with the blood (n = 139), in the other one the veins were empty (n = 140) to simulate the patient's position on the operating table. After the procedure, every vein segment was cut longitudinally, unfolded and its inner circumference was measured and compared to inner circumference of untreated part of the same venous segment. RESULTS: Maximal shrinkage and minimal number of perforations were achieved using lower or medium power (8 to 12 W). Circumference of shrunken vein compared to normal venous circumference (100%) was as follows: 50% (power 5W), 45% (power 8W), 40% (power O1W), 45% (power 12W) and 58.6% (power 15W). These differences are statistically significant (p < 0.001). When higher power was used (15W), the perforations and carbonisations were more frequent and total energy was lower but the difference in amount of energy delivered was not significant (p = 0.379). CONCLUSIONS: Shrinkage of the vein depends on laser power. Based on our experiments, we recommend photocoagulation with lower or medium power (8 to 12 W) and slower pull-back (0.2 to 2 mm/s) to achieve the sufficient energy per centimeter of the vein and the optimal long-term outcome.

[Neovascularisation as a cause of recurrence after varicose veins operation]. / Neovaskularizace jako prícina recidivy po operaci varixu dolních koncetin.

AIMS: Following surgical therapy, new varicose veins may develop, in particular at the site of the previous saphenofemoral junction. The objective of this study is the appreciation of the causes of the bad results of surgical procedures in the treatment of varicose veins and the proposal of the possibilities of their prevention. MATERIAL AND METHODS: Retrospective study of the group of 404 patients (573 procedures) with the diagnosis of the recurrence after previous radical surgery was performed. After exclusion of perforator refluxes, the most frequently, the great saphenous vein territory was affected (86%), followed by the small saphenous vein territory (14%). The group of 30 consecutive patients (35 limbs) with saphenofemoral or saphenopopliteal recurrence was selected for this study. Based on preoperative ultrasound and per-operative morphological findings, in 12 patients (14 limbs) - 8 women and 4 men, meticulous histopathological examination of the venous tissue block from the saphenofemoral or saphenopopliteal region, VEGF (Vascular endothelial growth factor) and protein S-100 investigation were performed. RESULTS: In 14 limbs with sonographic and clinical suspition for neovascularisation, this entity was confirmed in 11 of them (79%) which represents 31.42% of the whole group. CONCLUSIONS: The varicose veins recurrences can be observed not only after technically or tactically imperfect primary procedure (which is surely the most common cause of the varicose veins recurrence), but also after the operations performed by the experienced venous surgeon in the perfect way. Neovascularisation explains a certain number of postoperative recurrences despite correctly conducted disconnection of the saphenous termination. The endovascular procedures (endovenous laser or radiofrequency saphenous obliteration) without open groin access can minimise the possibility of this complication.

Infection in hip arthroplasty after previous injection of steroid.

Immunosuppression following intra-articular injections of steroid into the hip may interfere with asepsis in a subsequent total hip arthroplasty (THA). We have undertaken a retrospective, matched, cohort study of infective complications after THA, in 40 patients who had received such an injection and 40 who had not. In the injection group there were five revisions, four of which were for deep infection. There were none in the matched group. The overall rate of revision in our database of 979 primary THAs was 1.02%. Six additional patients who had received injections underwent investigation for infection because of persistent problems in the hip as compared with one in the control group.

[Endovascular therapy of truncal varicose veins of the lower extremities with a diode laser]. / Endovaskulární lécba kmenových varixu dolních koncetin diodovým laserem.

The authors present their experiences with new miniinvasive treatment of varicose veins--endovenous diode laser system. The results of 60 procedures treating truncal varices are reported with special concern to percutaneous access technique under ultrasound guidance. This new concept based on haemodynamic ultrasound findings is compared to the traditional surgical technique of cross-sectomy and stripping.

[Surgery of the saphenous-popliteal junction: a delicate procedures with potential risks]. / Operace saféno-popliteální junkce: delikátní výkon s mozným rizikem.

UNLABELLED: The authors evaluate the results achieved in two groups of patients operated on for varicose veins in small saphenous vein (SSV) territory in 3 year interval. In the first group gathered from January to December 1998 (114 patients--36 men and 78 women, 123 procedures--118 primary and 5 re-do) the operative indication was based on the clinical examination and continual doppler evaluation. These patients were operated on in general, spinal or local and flash general anaesthesia. In the second group gathered in the same period of the year 2001 (72 patients--21 men and 51 women) 75 procedures were performed (3 patients with bilateral operation). In this group, 49 patients with 50 procedures were selected. The diagnosis was based not only on clinical and continuous doppler examination, but mainly on colour flow duplex mapping. The operation was performed on strictly ambulatory basis using pure local anaesthesia completed with small dose of sedation. Any patient needed complementary sclerotherapy one month after procedure. In mid-term follow-up complementary conservative treatment was necessary in 51 p.c. of the whole series. CONCLUSION: Use of colour coded duplex ultrasound in preoperative evaluation of varicose veins patients enabled us to precise preoperative diagnosis, to diminish the number of aggressive surgical procedures in favour of less traumatic operations and to perform this surgery on ambulatory basis. Nevertheless, small sahenous vein surgery still remains delicate and sometimes also hazardous.

Modified iliofemoral approach for major isolated acetabular revision arthroplasty.

Multiple specialized exposures have been described for revision total hip arthroplasty. In this article, we report on a series of 7 patients who underwent major isolated acetabular revision surgery through a modified iliofemoral approach. The use of this approach was deemed desirable because of the individual pathology present in each case, particularly major acetabular bone loss (Paprosky 2C/3B). However, successful reconstruction was achieved in all cases with the most frequent complication being meralgia paresthetica.

The phosphinomethylmalate isomerase gene pmi, encoding an aconitase-like enzyme, is involved in the synthesis of phosphinothricin tripeptide in Streptomyces viridochromogenes.

Streptomyces viridochromogenes Tü494 produces the antibiotic phosphinothricin tripeptide (PTT). In the postulated biosynthetic pathway, one reaction, the isomerization of phosphinomethylmalate, resembles the aconitase reaction of the tricarboxylic acid (TCA) cycle. It was speculated that this reaction is carried out by the corresponding enzyme of the primary metabolism (C. J. Thompson and H. Seto, p. 197-222, in L. C. Vining and C. Stuttard, ed., Genetics and Biochemistry of Antibiotic Production, 1995). However, in addition to the TCA cycle aconitase gene, a gene encoding an aconitase-like protein (the phosphinomethylmalate isomerase gene, pmi) was identified in the PTT biosynthetic gene cluster by Southern hybridization experiments, using oligonucleotides which were derived from conserved amino acid sequences of aconitases. The deduced protein revealed high similarity to aconitases from plants, bacteria, and fungi and to iron regulatory proteins from eucaryotes. Pmi and the S. viridochromogenes TCA cycle aconitase, AcnA, have 52% identity. By gene insertion mutagenesis, a pmi mutant (Mapra1) was generated. The mutant failed to produce PTT, indicating the inability of AcnA to carry out the secondary-metabolism reaction. A His-tagged protein (Hispmi*) was heterologously produced in Streptomyces lividans. The purified protein showed no standard aconitase activity with citrate as a substrate, and the corresponding gene was not able to complement an acnA mutant. This indicates that Pmi and AcnA are highly specific for their respective enzymatic reactions.