Hymenoptera-venom-induced upregulation of the basophil activation marker ecto-nucleotide pyrophosphatase/phosphodiesterase 3 in sensitized individuals

BACKGROUND

Bee and wasp venoms are potent allergens capable of inducing severe clinical reactions. To detect immediate-type hypersensitivity to these allergens, a rapid in vitro test was developed that relies on the upregulation of ecto-nucleotide pyrophosphatase/phosphodiesterase 3 (E-NPP3) on activated basophils.

METHODS

Blood basophils of 13 healthy donors and 22 patients allergic to bee or wasp venom were analyzed for E-NPP3 (CD203c) expression using monoclonal antibody 97A6. Basophils were analyzed by flow cytometry after activation with anti-IgE antibody or allergen. Venom-induced E-NPP3 upregulation on basophils was compared with diagnostic parameters, including skin tests and assessment of specific IgE. In selected samples, the increase in E-NPP3 expression on activated basophils was compared with histamine release and CD63 upregulation.

RESULTS

In 20/22 patients sensitized to wasp or bee venom, E-NPP3 expression on basophils was upregulated in response to activation by allergen or anti-IgE. The maximum increase in E-NPP3 expression (above ten times of baseline) was achieved after 15 min of stimulation with 1 microg/ml of allergen or anti-IgE antibody. Sensitized individuals who failed to upregulate E-NPP3 in response to IgE receptor cross-linking also failed to induce histamine release and CD63 upregulation.

CONCLUSIONS

Flow cytometric determination of hymenoptera-venom-induced upregulation of E-NPP3 is a novel in vitro test to identify sensitized individuals.

Molecular and immunological characterization of arginine kinase from the Indianmeal moth, Plodia interpunctella, a novel cross-reactive invertebrate pan-allergen

IgE recognition of indoor allergens represents a major cause of allergic asthma in atopic individuals. We found that 52 of 102 patients suffering from allergic symptoms indoors contained IgE Abs against allergens from the Indianmeal moth (Plodia interpunctella), a ubiquitous food pest. Using serum IgE from a moth-sensitized patient we screened an expression cDNA library constructed from P. interpunctella larvae. cDNAs coding for arginine kinase (EC 2.7.3.3), a 40-kDa enzyme commonly occurring in invertebrates that is involved in the storage of such high-energy phosphate bonds as phosphoarginine, were isolated. Recombinant moth arginine kinase, designated Plo i 1, was expressed in Escherichia coli as a histidine-tagged protein with enzymatic activity, and purified to homogeneity by nickel chelate affinity chromatography. Purified recombinant arginine kinase induced specific basophil histamine release and immediate as well as late-phase skin reactions. It reacted with serum IgE from 13 of the 52 (25%) moth-allergic patients and inhibited the binding of allergic patients' IgE to an immunologically related 40-kDa allergen present in house dust mite, cockroach, king prawn, lobster, and mussel. Our results indicate that arginine kinases represent a new class of cross-reactive invertebrate pan-allergens. Recombinant arginine kinase may be used to identify a group of polysensitized indoor allergic patients and for immunotherapy of these individuals.

[Distant healing and clinical research]

Distant healing is one of the most controversially discussed methods of complementary medicine. In the first section this paper outlines the history of spiritual healing and describes some possible definitions and different methods of spiritual healing. Based on a literature search in Medline, EMBASE, Current Contents, Allied and Complementary Medicine Database (AMED) as well as a manual tracking, current distant healing studies (excluding therapeutic touch studies) (n = 16) and some review articles (n = 6) are outlined in the second section. In addition, the randomized clinical double-blind studies (n = 12) are judged as to their formal quality by means of the Jadad Scale and the Internal Validity Scale (IV). Based on the controversially discussed study by Harris et al., some discussion points in the research field of spiritual healing are presented in the third section of this paper. From the evidence contained in the studies of this review article, no firm conclusions about the efficacy or inefficacy of healing can yet be made.

Treatment of focal hyperhidrosis with botulinum toxin type A: long-term follow-up in 61 patients

BACKGROUND

The blocking action of botulinum toxin type A (BTX-A) on cholinergically innervated sweat glands has been used successfully to treat patients with focal hyperhidrosis.

OBJECTIVES

To investigate the long-term efficacy and safety of intradermal injections of BTX-A.

METHODS

We performed an open-label study in 61 patients treated over a period of 3 years for axillary or palmar hyperhidrosis. A total dose of 400 mU BTX-A (Dysport) was injected into both axillae or 460 mU BTX-A (Dysport) into both palms. The injections were repeated after relapse. Objective quantification of sweat production was performed using digitized ninhydrin-stained sheets.

RESULTS

Four weeks after BTX-A treatment the median reduction in sweat production was 71% compared with baseline (P < 0.001) in the axillary group and 42% (P = 0.005) in the palmar group. Subjective assessment of sweat production by the patients using a visual analogue scale (0, no sweating; 100, the most severe sweating) showed a significant reduction in both the axillary (P < 0.001) and palmar groups (P < 0.001). Secondary disturbances due to focal hyperhidrosis interfering with daily activities were markedly improved in both groups. The median time interval between the sets of injections was 34 weeks for axillary hyperhidrosis and 25 weeks for palmar hyperhidrosis. The treatment of palmar hyperhidrosis was complicated by transient but not disabling weakness of the small hand muscles in nine of 21 patients.

CONCLUSIONS

Repeated intradermal injections of BTX-A in patients with axillary and palmar hyperhidrosis are as effective as first treatments.

Compliance with follow-up and prognosis among patients with thin melanomas

The aim of this study was to report on the compliance with follow-up among patients with thin melanomas. We also examined the prognosis of patients with recurrent disease and whether there were any differences in prognosis associated with the time between the last follow-up examination and the onset of recurrence. A retrospective analysis of the records of 513 consecutive patients (50.3% males, mean age: 52.8+/-16.9 years) with thin melanomas (<1.5 mm Breslow thickness) was carried out. The estimated cumulative proportion of patients who still continued their follow-up examinations 5 years after diagnosis of the primary tumour was 55.3% (95% Confidence Interval (CI): 50.4--60.2%). The mean annual drop-out rate was 11.2%. The drop-out rate was similar for males and females and was not influenced by the patients' age or the tumour thickness. Among 263 patients who continued follow-up, 50.2% (n=132) were not compliant with the time schedule. 20 patients presented with recurrent disease after a median of 35.9 months (25--75% percentiles: 16.7--46.5 months). Six patients who did not have a follow-up examination within 1 year before the onset of recurrence presented with more advanced disease and had a worse prognosis (median survival: 12.5 months, hazard ratio: 3.5, 95% CI: 1.1--17.1, P=0.04), than those patients, who had a recent follow-up examination before the onset of recurrence (n=14, median survival: 22.3+ months). In the majority of recurrent cases with good prognosis, metastatic disease was confined to the regional lymph nodes and the presumptive diagnosis of metastatic disease was either made by palpation or by sonography of the regional lymph nodes. The observed drop-out rate of patients during the first 5 years of follow-up is substantial and does not depend on the patients' age, sex or on the tumour thickness. Although the frequency of recurrences among patients with thin melanomas is low, regular follow-up examinations including physical examination, as well as palpation and sonography of the regional lymph nodes, are essential.

A comparison of machine learning methods for the diagnosis of pigmented skin lesions

We analyze the discriminatory power of k-nearest neighbors, logistic regression, artificial neural networks (ANNs), decision tress, and support vector machines (SVMs) on the task of classifying pigmented skin lesions as common nevi, dysplastic nevi, or melanoma. Three different classification tasks were used as benchmarks: the dichotomous problem of distinguishing common nevi from dysplastic nevi and melanoma, the dichotomous problem of distinguishing melanoma from common and dysplastic nevi, and the trichotomous problem of correctly distinguishing all three classes. Using ROC analysis to measure the discriminatory power of the methods shows that excellent results for specific classification problems in the domain of pigmented skin lesions can be achieved with machine-learning methods. On both dichotomous and trichotomous tasks, logistic regression, ANNs, and SVMs performed on about the same level, with k-nearest neighbors and decision trees performing worse.

A ten-year analysis of demographic trends for cutaneous melanoma: analysis of 2501 cases treated at the University Department of Dermatology in Vienna (1990-1999)

BACKGROUND

The aim of the study is to provide recent demographic data on cutaneous melanoma in Austria.

PATIENTS AND METHODS

Patients with primary cutaneous melanoma diagnosed between January 1, 1990 and December 31, 1999 were included in the analysis. Data were retrieved from the melanoma registry of the University Department of Dermatology in Vienna.

RESULTS

In the observation period, 2501 cutaneous melanomas were diagnosed in 2427 patients (mean age: 55.4 yrs; 51.2% females). A total of 267 (10.7%) cutaneous melanomas were in situ, and 2234 (89.3%) were invasive. The median invasion thickness according to Breslow for invasive melanomas was 0.98 mm (25%-75% percentiles: 0.55-2.00 mm). We observed a significant trend towards thicker tumors with increasing age (p < 0.001). In patients less than fifty years of age, a significantly higher Breslow thickness was observed in men than in women (0.90 mm versus 0.80 mm, p = 0.03). The median Breslow thickness of invasive melanoma decreased from 1.20 mm in 1990 to 0.92 mm in 1999 (p for trend, < 0.001). Compared to women, men had melanomas more frequently on the back (43.8% versus 24.4%, p < 0.001). In women, melanomas were more frequently found on the lower legs than in males (21.5% versus 6.7%, p < 0.001). In a multivariate model, invasion thickness according to Breslow was the single most important predictor of survival.

CONCLUSION

Our data confirm recent reports from other European countries with regard to the decline in tumor thickness of cutaneous melanoma. Our data also demonstrate a need for improving early diagnosis, particularly in certain subgroups of patients.

The dermatoscope: a potential source of nosocomial infection?

Dermatoscopes are directly placed on the skin of patients and therefore may harbour potentially pathogenic bacteria. In this study we assessed bacterial contamination of dermatoscopes during routine use and examined the effectiveness of isopropyl alcohol and disposable lens covers. Aerobic bacterial cultures were performed on randomly selected dermatoscopes after examination of 39 patients. In addition, bacterial contamination of dermatoscopes after cleaning with 70% isopropyl alcohol and after using a disposable transparent lens cover was tested. Bacteria such as Staphylococcus epidermidis, Micrococcus species and Corynebacterium species, which are usually present on the skin, were repeatedly identified. In addition, rare bacteria such as Moraxella species were found. Known nosocomial micro-organisms such as Staphylococcus aureus were recovered from hospitalized patients. Disinfection with 70% isopropyl alcohol and the use of a disposable lens cover significantly reduced the number of bacteria. Image quality was identical with and without the use of a transparent lens cover. Dermatoscopes harbour potential pathogens and may be a source of bacterial transmission. Isopropyl alcohol is an effective cleaning agent for dermatoscopes. Disposable lens covers completely prevented bacterial transmission and are therefore recommended for routine dermatoscopy, especially in hospitalized patients.

Automated melanoma recognition

A system for the computerized analysis of images obtained from ELM has been developed to enhance the early recognition of malignant melanoma. As an initial step, the binary mask of the skin lesion is determined by several basic segmentation algorithms together with a fusion strategy. A set of features containing shape and radiometric features as well as local and global parameters is calculated to describe the malignancy of a lesion. Significant features are then selected from this set by application of statistical feature subset selection methods. The final kNN classification delivers a sensitivity of 87% with a specificity of 92%.

Metabolism of amiodarone (part I): identification of a new hydroxylated metabolite of amiodarone

Amiodarone (AMI) is a potent antiarrhythmic drug, but its metabolism has not yet been fully documented. Mono-N-desethylamiodarone (MDEA) is its only known metabolite. Our preliminary investigations using rabbit liver microsomes had shown that in vitro AMI was biotransformed to MDEA, and the latter was rapidly further biodegraded to other unknown products. The aim of the present study was to investigate the chemical structure of the biotransformed compound of MDEA. Upon incubation of MDEA with rabbit liver microsomes and NADPH as cofactor, MDEA was biotransformed into three unknown products: X1, X2, and X3. The products were purified using chromatography. The chemical structure of the major product, X1, was investigated in detail. HPLC-ESI-MS revealed that MDEA had been oxygenated. Hydrogen-deuterium exchange experiments showed that the X1 molecule contained one exchangeable hydrogen atom more than its precursor MDEA, indicating that MDEA had been hydroxylated. Further results from ESI-MS/MS analysis indicated that the site of hydroxylation was the n-butyl side chain. NMR analysis (1H NMR, one-dimensional-total correlation spectroscopy, and heteronuclear multiple-bond correlation spectroscopy) established the 3-position (omega-1) of the butyl moiety as the specific carbon atom that is hydroxylated. Rat liver microsomes were also able to catalyze MDEA hydroxylation. Compound X1, as analyzed by HPLC-ESI-MS and ESI-MS/MS, was detected in the liver, heart, lung, and kidney tissue of four rats receiving AMI, suggesting that the hydroxylated MDEA was a secondary metabolite of AMI.

CONCLUSION

in mammals, MDEA is hydroxylated to the secondary metabolite of AMI [2-(3-hydroxybutyl)-3-[4-(3-ethylamino-1-oxapropyl)-3,5-diiodobenzoyl]-benzofuran].

Computer-aided epiluminescence microscopy of pigmented skin lesions: the value of clinical data for the classification process

Early melanoma is often difficult to differentiate from benign pigmented skin lesions (PSLs). Digital epiluminescence microscopy (DELM) and automated image analysis could represent possible aids for inexperienced clinicians. We designed an automated computerized image analysis system that has the potential for use as an additional tool for the differentiation of melanoma from dysplastic naevi and common naevi. The PC-based pilot system was attached to a common DELM system as the image source. Digital images of PSLs were automatically segmented and a panel of 107 morphological parameters were measured. Additionally, seven clinical parameters were evaluated and used as an additional source of information. Neural networks were then trained to distinguish melanoma from benign PSLs. One class of networks was trained solely based on the morphometric features, whereas the second class of networks was trained on the combination of morphometric and clinical features. The automatic segmentation algorithm was correct in 96% of cases. Using three-way receiver operating characteristic (ROC) analysis, for networks trained solely on morphometric features the volume under surface (VUS) was 0.617 (SD 0.036). The performance was significantly better for networks trained on the combination of both morphometric and clinical features (VUS = 0.682, SD 0.035). In a dichotomous model, distinguishing benign lesion (common naevi + dysplastic naevi) from melanoma, the area under the curve (AUC) from two-way ROC analysis was 0.942 (SD 0.018) for networks trained solely on morphometric features and 0.968 (SD 0.012) for those trained on the combination of clinical and morphometric data (P= NS). Automated feature extraction from PSLs and the training of neural networks as classifiers has thus shown satisfactory performance in a large scale experiment. The addition of clinical data significantly increases the diagnostic performance for distinguishing three classes of lesions (i.e. common naevi, dysplastic naevi and melanoma). Such integrated systems hold promise as a decision aid for the diagnosis of PSLs.

Follow-up of melanocytic skin lesions with digital epiluminescence microscopy: patterns of modifications observed in early melanoma, atypical nevi, and common nevi

BACKGROUND

Digital epiluminescence microscopy (DELM) has been reported to be a useful technique for the follow-up of melanocytic nevi. One of the promises of this technique is to identify modifications over time that indicate impending or incipient malignancy and to facilitate surveillance of melanocytic skin lesions, particularly in patients with multiple clinically atypical nevi.

OBJECTIVE

Our purpose was to report on patterns of modifications over time observed in benign melanocytic skin lesions and melanoma.

METHODS

A total of 1862 sequentially recorded DELM images of melanocytic lesions from 202 patients (mean age, 36.1 years; 54.0% female patients) with multiple clinically atypical nevi were included in the analysis. The median follow-up interval was 12. 6 months. Melanocytic lesions with substantial modifications over time (enlargement, changes in shape, regression, color changes or appearance of ELM structures known to be associated with melanoma) were excised and referred to histopathologic examination.

RESULTS

A total of 75 melanocytic skin lesions (4.0%) from 52 patients (mean age, 33.3 years; 63.5% female patients) showed substantial modifications over time and were excised and referred to histopathologic examination. Eight changing lesions were histologically diagnosed as early melanomas. These lesions frequently showed focal enlargement associated with a change in shape as well as appearance of ELM structures that are known to be associated with melanoma. In contrast, the majority of benign changing lesions (common and atypical nevi) showed symmetric enlargement without substantial structural ELM changes. Six of the 8 patients in whom melanoma developed were unaware of the fact that the lesion had changed over time.

CONCLUSION

We demonstrate that follow-up of melanocytic lesions with DELM helps to identify patterns of morphologic modifications typical for early melanoma. DELM may therefore serve as a useful tool to improve the surveillance of patients with multiple atypical nevi.

Comparing three-class diagnostic tests by three-way ROC analysis

Three-way ROC surfaces are based on a generalization of dichotomous ROC analysis to three-class diagnostic tests. The discriminatory power of three-class diagnostic tests is measured by the volume under the ROC surface. This measure can be given a probabilistic interpretation similar to the equivalence of the c-index to the area under the ROC curve. This article presents a method to calculate nonparametric estimates of the variance of the volume under the surface using Mann-Whitney U statistics. As a simple extension of this result, it is possible to calculate covariance estimates for the volume under the surface. This allows the statistical comparison of two tests used for diagnostic tasks with three possible outcomes. The formulas derived are validated on synthetic data and applied to a three-class data set of pigmented skin lesions. It is shown that a neural network algorithm trained on clinical data and lesion features performs better than one trained on only the lesion features.

Isolation and expression of a novel member of the CITED family

Chicken CITED3 (cCITED3) is a novel gene, which is expressed in the pre-somitic mesoderm, the mesonephric tubules, the Wolffian ducts and collecting tubules of the developing urogenital system and in the cranial sensory ganglia. Sequence analysis revealed that cCITED3 encodes a protein which contains two conserved domains that have been described for members of the CITED family.

ASW: a gene with conserved avian W-linkage and female specific expression in chick embryonic gonad

Vertebrates exhibit a variety of sex determining mechanisms which fall broadly into two classes: environmental or genetic. In birds and mammals sex is determined by a genetic mechanism. In mammals males are the heterogametic sex (XY) with the Y chromosome acting as a dominant determiner of sex due to the action of the testis-determining factor, SRY. In birds females are the heterogametic sex (ZW); however, it is not known whether the W chromosome carries a dominant ovary-determining gene, or whether Z chromosome dosage determines sex. Using an experimental approach, which assumes only that the sex-determining event in birds is accompanied by sex-specific changes in gene expression, we have identified a novel gene, ASW (Avian Sex-specific W-linked). The putative protein for ASW is related to the HIT (histidine triad) family of proteins. ASW shows female-specific expression in genital ridges and maps to the chicken W chromosome. In addition, we show that, with the exception of ratites, ASW is linked to the W chromosome in each of 17 bird species from nine different families of the class Aves.

Increased blood pressure response to the cold pressor test in pregnant women developing pre-eclampsia

OBJECTIVES

Recent data indicate an increased vascular reactivity due to an overactivity of the sympathetic nervous system in women with pre-eclampsia. We therefore evaluated whether this increased vascular reactivity can be detected prior to the clinical manifestation of preeclampsia by the use of a physiological stimulus.

DESIGN

Prospective data collection.

SETTING

Clinic of Obstetrics and Gynecology in a 2000 bed tertiary care hospital.

PARTICIPANTS

One hundred and twenty-three pregnant women between the 16th to 20th week of gestation.

INTERVENTIONS

A cold pressor test was performed by positioning an ice-bag on the forehead of the woman for 3 min. Blood pressure and heart rate were monitored by a continuous, noninvasive blood pressure measurement device during the stimulus and after removal of the icebag. A clinical follow-up was carried out by review of the charts after delivery to identify those women who have developed pre-eclampsia.

RESULTS

Ten (8%) out of 123 pregnant women developed pre-eclampsia. During the cold pressor test systolic as well as diastolic blood pressure increased significantly and was more pronounced in women developing pre-eclampsia compared with healthy pregnant women (systolic blood pressure: 14.2 +/- 5.5 versus 8.5 +/- 7.2 mmHg, P= 0.02; diastolic blood pressure: 7.3 +/- 4.9 versus 3.9 +/- 4.7 mmHg, P=0.03). The change in heart rate was similar between both groups (8 +/- 2.6 versus 10.4 +/- 6.4 beats/min, not significant).

CONCLUSIONS

An increased vasoconstrictive response to a physiological stimulus is present in women with pre-eclampsia as a sign of an increased vascular reactivity prior to clinical manifestation of the disease. The cold pressor test may be a suitable diagnostic tool to identify women, who will develop pre-eclampsia. However, future studies in larger cohorts are required to establish the final value of this test.

Realization of a CPR using HL7 queries from communication server to information server

A communication server is often used in Germany to interface legacy systems. It handles the translation, duplication, and transmission of messages to all systems that might need this information. Based on the principles of "for every data there is only one master" and "information on demand" we have built an information server that reduces the messages required and simplifies the handling of messages, the update of data already sent compared to a communication server. It also allows to implement a security policy as required by the German data privacy legislature.

Frequency and characteristics of enlarging common melanocytic nevi

OBJECTIVE

To analyze the frequency and characteristics of enlarging common melanocytic nevi.

DESIGN

Cohort study using digital epiluminescence microscopy (ELM) for documentation and follow-up, with a median follow-up interval of 11.4 months.

SETTING

A dermatology department at a university hospital in Vienna, Austria.

PATIENTS

One thousand six hundred twelve melanocytic nevi appearing clinically as common nevi, obtained from 385 patients (mean [+/-SD] age, 34.2 +/- 14.8 y; 55.6% female).

INTERVENTIONS

Follow-up examination and documentation by digital ELM.

MAIN OUTCOME MEASURES

Frequency of enlarging nevi according to age and comparison of ELM features observed in enlarging and nonenlarging nevi.

RESULTS

Enlargement was found in 5.3% (n = 86) of nevi. The frequency of enlarging nevi was inversely related to age (P<.001), in that enlarging nevi were common in patients younger than 20 years and relatively rare in older age groups. Epiluminescence microscopy revealed a peripheral rim of brown globules in 48.8% (n = 42) of enlarging nevi. In contrast, a peripheral rim of brown globules was found in only 0.7% (n = 11) of nevi without enlargement (P<.001). Enlarging nevi that were excised in children and adolescents showed no histological signs of atypia. In older age groups, 48.1% of excised enlarging nevi that were clinically diagnosed as common nevi showed some histological signs of atypia. None of the excised enlarging lesions was histologically diagnosed as melanoma.

CONCLUSIONS

The frequency of enlarging common nevi is inversely related to age. In the absence of clinical signs of atypia, enlargement alone does not indicate malignancy. A peripheral rim of brown globules is a characteristic ELM feature of symmetrically enlarging melanocytic nevi.

The interpretation of test results

BACKGROUND

Dermatologists need to interpret an increasing number of research studies and diagnostic tests. Understanding the techniques for interpreting test results and making decisions based upon those tests represent important tools for decision making for both clinicians and researchers.

OBJECTIVE

This article focuses briefly on the key parameters of diagnostic tests: sensitivity, specificity, prevalence, predictive values, likelihood ratios, and the concept of receiver-operating-characteristic (ROC) curves. A simple example is presented in a step-by-step manner.

CONCLUSION

The principles of interpreting test results are easy to learn and applicable in daily clinical routine. Therefore, dermatologists should be familiar with the concepts outlined in this paper.

Function of human mitochondrial 2,4-dienoyl-CoA reductase and rat monofunctional Delta3-Delta2-enoyl-CoA isomerase in beta-oxidation of unsaturated fatty acids

Human 2,4-dienoyl-CoA reductase (2,4-reductase; DECR) and rat monofunctional Delta(3)-Delta(2)-enoyl-CoA isomerase (rat 3, 2-isomerase; ECI) are thought to be mitochondrial auxiliary enzymes involved in the beta-oxidation of unsaturated fatty acids. However, their function during this process has not been demonstrated. Although they lack obvious peroxisomal targeting signals (PTSs), both proteins have been suggested previously to also occur in the mammalian peroxisomal compartment. The putative function and peroxisomal location of the two mammalian proteins can be examined in yeast, since beta-oxidation of unsaturated fatty acids is a compartmentalized process in Saccharomyces cerevisiae requiring peroxisomal 2,4-dienoyl-CoA reductase (Sps19p) and peroxisomal 3, 2-isomerase (Eci1p). A yeast sps19Delta mutant expressing human 2, 4-reductase ending with the native C-terminus could not grow on petroselinic acid [cis-C(18:1(6))] medium but could grow when the protein was extended with a PTS tripeptide, SKL (Ser-Lys-Leu). We therefore reason that the human protein is a physiological 2, 4-reductase but that it is probably not peroxisomal. Rat 3, 2-isomerase expressed in a yeast eci1Delta strain was able to re-establish growth on oleic acid [cis-C(18:1(9))] medium irrespective of an SKL extension. Since we had shown that Delta(2,4) double bonds could not be metabolized extra-peroxisomally to restore growth of the sps19Delta strain, we postulate that rat 3,2-isomerase acted on the Delta(3) unsaturated metabolite of oleic acid by replacing the mutant's missing activity from within the peroxisomes. Immunoblotting of fractionated yeast cells expressing rat 3, 2-isomerase in combination with electron microscopy supported our proposal that the protein functioned in peroxisomes. The results presented here shed new light on the function and location of human mitochondrial 2,4-reductase and rat monofunctional 3,2-isomerase.