[Ulcerative stomatitis as clinical clue to inadvertent methotrexate overdose]

Gastrointestinal side effects and the development of toxic liver fibrosis are well-known side effects of low dose methotrexate therapy. A female patient receiving a long term low dose methotrexate therapy for a seronegative chronic polyarthritis developed an ulcerative stomatitis, as clinical clue to an inadvertently given methotrexate overdose. A summary of other side effects of methotrexate and of oral side effects of other cytostatic agents and immunosuppressive drugs is given.

The non-steroidal anti-inflammatory drug tepoxalin inhibits interleukin-6 and alpha1-anti-chymotrypsin synthesis in astrocytes by preventing degradation of IkappaB-alpha

Tepoxalin is a structurally and functionally novel non-steroidal anti-inflammatory drug (NSAID) with potent anti-inflammatory and analgesic properties. Apart from its inhibitory effect on cyclooxygenase activity, tepoxalin is able to inhibit production of cytokines in peripheral cells outside the CNS. No data, however, are available concerning the effects of this drug in the CNS. Since cytokines such as interleukin-1 (IL-1) or interleukin-6 (IL-6) as well as acute-phase proteins such as alpha1-anti-chymotrypsin (ACT) participate in the etiopathology of Alzheimer's disease (AD), we were interested whether tepoxalin is able to inhibit the synthesis of these immunomodulators in primary rat microglia and astrocytes as well as in the human astrocytoma cell line U373 MG. We found that tepoxalin markedly inhibits IL-1beta-induced IL-6 and ACT synthesis in astrocytes and the synthesis of IL-1beta and IL-6 in lipopolysaccharide (LPS)-stimulated microglial cells. Electrophoretic mobility shift and reporter gene assays revealed that tepoxalin exerts its inhibitory effect through the inhibition of nuclear factor kappaB (NF-kappaB), a transcription factor involved in the induction of IL-1, IL-6 and ACT gene expression. We show that inhibition of NF-kappaB activation by tepoxalin is mediated by preventing IkappaB-alpha degradation. Based on this inhibitory effect of tepoxalin on cytokine and ACT synthesis and the documented therapeutic efficacy of NSAIDs in AD, we conclude that tepoxalin may be of therapeutic benefit for the treatment of AD patients and should therefore be tested in clinical trials.

[Goal-oriented outcome measurement in inpatient or day care orthopedic-rheumatologic rehabilitation of patients with back pain]

The comparison of patient characteristics and effectiveness of inpatient rehabilitation (IPR) and outpatient rehabilitation (OPR) is of growing importance in terms of flexible and cost-effective structures in rehabilitation. The effectiveness of the treatment is measured applying a goaloriented approach based on the individual rehabilitation goals and the attainment of these goals at the end of the programme. The frequencies of rehabilitation goals chosen by patients in IPR and OPR are similar. Decrease of pain, improvement of muscular strength and improvement of the range of motion are the main goals of patients in IPR and OPR (92-56%). No relevant differences can be seen considering the effectiveness of IPR and OPR, except for the markedly higher improvement of vitality in IPR. Patients in need of rehabilitation whose primary rehabilitation goal is improvement of vitality should therefore preferentially be referred to an inpatient rehabilitation programme.

Quantification of conversion and degradation of circulating angiotensin in rats

The aim of the present study was to quantify with a uniform technique the rates of conversion of ANG I to ANG II in the lung and kidney and the degradation of both peptides to biologically inactive products in the pulmonary, renal, and systemic circulation. We infused the peptides intravenously, into the left ventricle, and into the left renal artery of rats and compared their effects on renal blood flow. The measured change in renal blood flow was used as a bioassay parameter to estimate the concentration of circulating ANG II. Mathematical analysis of our data allowed us to calculate conversion and degradation rates. Furthermore, the role of aminopeptidases A (EC 3.4.11.7) and N (EC 3.4.11.2) in the degradation of the peptides in the kidney was investigated by intrarenal infusion of the inhibitor amastatin. Our results show that the conversion rate of ANG I is 75% in the pulmonary and 21% in the renal circulation. Both peptides are degraded by 5% in the pulmonary, by 67% in the systemic, and by 93% in the renal circulation. Amastatin prevented 60% of the renal degradation of the peptides to inactive products, and this effect could be attributed to inhibition of aminopeptidase N. The results indicate that the converting capacity of the kidney is of minor importance for endocrine generation of ANG II but could be useful for the paracrine production.

Usefulness of spoligotyping To discriminate IS6110 low-copy-number Mycobacterium tuberculosis complex strains cultured in Denmark

Mycobacterium tuberculosis complex strains cultured in Denmark have been analyzed by IS6110 restriction fragment length polymorphism (RFLP) on a routine basis from 1992 and onwards. Due to the influx of immigrants with tuberculosis, the number of strains harboring only one to five copies of IS6110 has increased steadily. Since the discriminatory power of IS6110 fingerprinting for such strains is poor, we have performed additional genotyping of all low-copy-number strains by the recently described PCR-based method known as spoligotyping. A total of 311 clinical strains were typed: 14 Mycobacterium bovis BCG, 48 M. bovis, and 249 M. tuberculosis strains. Spoligotyping correctly differentiated M. bovis and M. bovis BCG from M. tuberculosis strains, but it did not differentiate M. bovis from M. bovis BCG. All M. bovis BCG strains exhibited identical spoligotype patterns. The discriminatory power of spoligotyping of low-copy-number M. tuberculosis strains was higher than that of IS6110 fingerprinting. Based on RFLP typing solely, 83% of the low-copy-number M. tuberculosis strains were found to form part of a cluster, and 75% were found to form a cluster on the basis of spoligotyping. When the two techniques were combined, the amount of clustering decreased to 55%. The combination of these two techniques might be valuable in studying the epidemiology of M. tuberculosis strains harboring few copies of the IS6110 element.

Validation of a malnutrition screening tool for patients receiving radiotherapy

Nutrition screening identifies individuals who are malnourished or at risk of becoming malnourished and who may benefit from nutrition support. The aim of this study was to validate a new malnutrition screening tool (MST) in cancer patients undergoing radiotherapy. The MST was compared with the subjective global assessment (SGA) of nutritional status. One hundred and six patients attending two cancer care centres in Australia were independently rated as well nourished or malnourished using SGA and at risk or not at risk of malnutrition using the MST. Convergent validity of the MST was established by determining the ability of the MST to predict SGA. According to SGA, 89% of the patients were well nourished and 11% were moderately malnourished. According to the MST, 28% of patients were at risk of malnutrition. The MST had a sensitivity of 100% and a specificity of 81%. The positive predictive value was 0.4 and the negative predictive value was 1.0. The MST is easy to use and is a strong predictor of nutritional status. The malnutrition screening tool is a simple, quick, valid tool that can be used to identify radiation oncology outpatients who are at risk of malnutrition.

ANG II- and TxA(2)-induced mesenteric vasoconstriction in rats is mediated by separate cell signaling pathways

Studies in vitro have demonstrated that vasoconstrictor agents increase intracellular Ca(2+) and activate protein kinase C (PKC) to elevate vascular tone. The aim of the present study was to determine the importance of these signaling pathways for angiotensin II (ANG II) and thromboxane A(2) (TxA(2)) in regulating mesenteric blood flow (MBF) in vivo. In anesthetized rats increasing doses of ANG II or the TxA(2) agonist U-46619 were administered into the superior mesenteric artery to reduce MBF. Intra-arterial infusion of inhibitors served to examine the contribution of different pathways: 8-(diethylamino)octyl 3,4,5-trimethoxybenoate hydrochloride (TMB-8) to inhibit intracellular Ca(2+) release, nifedipine to block transmembrane Ca(2+) influx through the L-type Ca(2+) channel, and staurosporine to inhibit PKC. Each of the inhibitors attenuated ANG II-induced reductions in MBF, and all dose-response curves were shifted to the right to an approximately threefold higher ANG II dose. Combinations of the inhibitors revealed that their effects were additive; together they abolished the vasoconstrictor action of ANG II completely. In contrast, the dose-response curve for U-46619 was not affected by any of the inhibitors infused either separately or together. The results demonstrate that a rise in intracellular Ca(2+) and activation of PKC are major mediators of the vasoconstrictor effect of ANG II in mesenteric circulation, but they play a subordinate role, if any, for the effects of TxA(2). Because TxA(2) plays a major role only under pathological conditions, the uncontrolled vasoconstriction appears to be associated with the recruitment of novel signal transduction pathways.

An international dermatological image atlas on the WWW: practical use for undergraduate and continuing medical education, patient education and epidemiological research

We describe the development of an image database DOIA (Dermatological OnlIne Atlas) and present several spin-off projects using images of the atlas, e.g. student education using the atlas including results of an questionnaire evaluating computer-literacy, prerequisites and interests of students for using computers and the World-Wide-Web (WWW), a patient information system and an experiment to collect epidemiological data from patients with dermatological diseases via WWW. The database, available on the WWW at http:@www.derma.med.uni-erlangen.de, contains about 3,000 clinical images covering more than 540 dermatological diagnoses. It is designed for worldwide use; international submissions are encouraged. One aim of the project is to compile an international reference for dermatological images, containing images of high educational quality and also covering conditions on different skin types and rare diagnoses which are not commonly illustrated in ordinary textbooks. All images were originally mapped to the Erlanger Diagnosis Code, which is a proprietary modified ICD-9 key, later also to the UMLS (Unified Medical Language System). In addition, images are described with keys for the location, physical attributes of the location and clinical and histopathological features of the lesion. In order to facilitate the integration of the atlas into other web-based medical resources and to allow easy access to additional information, the Erlanger Diagnosis Code was mapped to the CUIs (unique concept identifiers) of the UMLS Metathesaurus. One purpose of the UMLS is to allow conversion of terms from one controlled medical vocabulary to another, thus, mapping of our diagnosis code to the UMLS CUIs allows simultaneous search for a given diagnosis in a number of other databases and also access to our image database from other databases. Mapping was successful for 619 out of 1383 dermatological diagnosis terms. For images with these diagnoses we are able to provide a hyperlink to other databases available on the Internet, such as MEDLINE, PDQ and OMIM, with automatic retrieval using the preferred vocabulary of the respective database. By grouping all diagnoses into sets with similar morphologies we further integrated a differential diagnosis mode. In order to educate patients via the Internet, a separate patient information system has been developed, using images of the electronic atlas. As an experiment to explore the feasibility of the Internet to gather epidemiological data from patients, users are asked to complete an electronic questionnaire covering signs for atopy. We conclude that an online image atlas has multiple educational, clinical and research applications.

Epidemiology of tuberculosis in HIV-infected patients in Denmark

Denmark is an area of low incidence of HIV and tuberculosis (TB). The number of newly reported cases of HIV has been stable during the 1990s, whereas the number of TB cases has doubled in Denmark in the past decade, mainly due to immigration. However, among native Danes the incidence of TB has increased in the younger age groups, indicating more newly infected persons. This study was performed in order to assess the impact of the HIV epidemic and immigration on TB incidence among native Danes. The study was also designed to reveal transmission patterns of TB among HIV-positive patients. Data from HIV-TB co-infected patients identified in the national registers of TB and AIDS from 1992-95 were collected retrospectively from medical records. Restriction fragment length polymorphism (RFLP) analyses of TB isolates from co-infected patients were compared with all patterns registered in the nationwide Danish RFLP database (approximately 1,700 patients). Sixty-seven co-infected patients were identified, 26 Danes and 41 immigrants, representing only 4% of all TB cases during the study period. Danish co-infected patients were part of a cluster, i.e. they had a RFLP-pattern identical to a pattern in the national RFLP database, more often than immigrants (83% vs. 45%, p < 0.005). In only 2 cases were co-infected Danes and immigrants part of the same cluster. Danish HIV-TB co-infected patients were more often intravenous drug users than were co-infected immigrants (p < 0.0005). In conclusion, we found no evidence to suggest that the increase in TB incidence among young Danes was caused by the HIV-epidemic or transmission from immigrants. TB among HIV-positive Danes is most often due to recent infection. The patients often belong to a subpopulation living in Copenhagen characterized by intravenous drug use.

Transgenic Lewis rats overexpressing the proteolipid protein gene: myelin degeneration and its effect on T cell-mediated experimental autoimmune encephalomyelitis

Transgenic Lewis rats overexpressing proteolipid protein (PLP) genes in peripheral and central nervous myelin were produced by microinjecting murine genomic PLP sequences into fertilized eggs. The mouse PLP gene shares 98.7% homology in the nucleotide sequence with its rat counterpart, but both are fully identical on protein level. Homozygous rats show tremors early in postnatal life, eventually develop seizures, and die before they reach weaning age, while hemizygous animals are phenotypically normal and have a normal life expectancy. Transgene expression in the central nervous system (CNS) has profound consequences for myelin formation and maintenance: approximately twofold overexpression of PLP/DM-20, as seen in homozygotes, results in apoptosis of mature, and a developmental arrest of the remaining immature oligodendrocytes. Severe dysmyelination ensues, associated with reactive astrogliosis and microglia activation/proliferation. Activation of microglia is also prominent in hemizygous rats with low levels of transgene overexpression. In these animals, myelin sheaths remain intact, but there is low-grade myelin degeneration throughout life witnessed by myelin uptake and activation of microglia and astrocytes, in the absence of the expression of major histocompatibility complex class II gene products. There were no spontaneous lymphocytic infiltrates in areas of myelin degeneration. However, hemizygous LEW.PLP rats were more sensitive to experimental autoimmune encephalomyelitis mediated by T cells specific for PLP, but not another encephalitogenic myelin protein, MBP.

Apoptosis of T lymphocytes in acute disseminated encephalomyelitis

Apoptosis has been shown to be an efficient mechanism involved in clearance of T lymphocytes from the brains of animals with acute experimental autoimmune encephalomyelitis (EAE), an animal model for human multiple sclerosis. In this report we describe a case of acute disseminated encephalomyelitis following general measles infection. In this disease, which closely mimics the pathology of acute EAE we found a high percentage (30%) of apoptotic T cells. This indicates that in both rodent and human brain clearance of T cell-mediated inflammation follows similar mechanisms.

Development of a valid and reliable malnutrition screening tool for adult acute hospital patients

Nutrition screening identifies individuals who are malnourished or at risk of becoming malnourished and who may benefit from nutrition support. The aim of this study was to develop a simple, reliable and valid malnutrition screening tool that could be used at hospital admission to identify adult acute patients at risk of malnutrition. The sample population included 408 patients admitted to an Australian hospital, excluding pediatric, maternity, and psychiatric patients. The ability of various nutrition screening questions to predict subjective global assessment (SGA) were examined in contingency tables. The combination of nutrition screening questions with the highest sensitivity and specificity at predicting SGA was termed the malnutrition screening tool (MST), and consisted of two questions regarding appetite and recent unintentional weight loss. Subjects who were at risk of malnutrition according to the MST had significantly lower mean values for the objective nutrition parameters (except immunologic parameters) and longer length of stays than subjects who were not at risk of malnutrition. Therefore convergent and predictive validity of the MST was established. The interrater reliability of the malnutrition screening tool was high (93-97%). The MST is a simple, quick, valid, and reliable tool which can be used to identify patients at risk of malnutrition.

Dose-finding study of epidoxorubicin and docetaxel as first-line chemotherapy in patients with advanced breast cancer

BACKGROUND

Anthracyclines and taxanes are the most active drugs against breast cancer and the search after their optimal combination is under intensive investigation in both the advanced and early disease settings. A dose-finding study of epidoxorubicin (E) and docetaxel (D) was conducted in advanced breast cancer (ABC) to define the maximum tolerated dose (MTD) of the combination with and without granulocyte colony-stimulating factor (G-CSF) support and to characterise its toxicity and activity profile.

PATIENTS AND METHODS

Forty-two patients who received neither palliative chemotherapy nor adjuvant anthracyclines (55% with dominant visceral disease and 66% with > or = 2 sites involved) with measurable/evaluable lesions, were treated at four dose levels starting from E 75 mg/m2 and D 75 mg/m2 to E 120 mg/m2 and D 85 mg/m2. A maximum of four cycles of the combination was given every three weeks and four additional cycles of single agent D were allowed in responding patients. Cardiac function was monitored at baseline and at every second course by echocardiography.

RESULTS

Febrile neutropenia (two patients) and prolonged, severe neutropenia (absolute neutrophil count (ANC) < 0.1 x 10(9)/l for more than three days; one patient) defined the MTD of the combination without G-CSF support at E 90 mg/m2 and D 75 mg/m2. G-CSF was then routinely administered from the subsequent dose level of E 120 mg/m2 and D 75 mg/m2. The MTD with G-CSF support was established at E 120 mg/m2 and D 85 mg/m2 (one patient with neutropenic fever together with failure of ANC recovery at day 21, three patients with ANC less than 0.1 x 10(9)/l for more than three days, one patient with both and one patient with grade 4 thrombocytopenia and toxic death from typhlitis while neutropenic). No severe neurotoxicity, mucositis, or fluid retention were observed and there were no clinical signs of cardiotoxicity. Antitumor activity was not a primary endpoint of the study: the overall response rate (ORR) in 40 evaluable patients was 60% (95% confidence interval: 43%-75%, 58% in liver disease, 84% in soft tissue) with no apparent dose-related effect. After a median follow-up of 19 months (range 2-30+), the overall time to progression (TTP) in nine patients without maintenance hormonal therapy was five months.

CONCLUSIONS

The combination of E and D proved to be an effective and safe regimen in poor- prognosis patients with ABC. G-CSF support allowed higher doses to be delivered safely but dose escalation did not translate into improved response rates (RR). The MTD without growth factors support was used, in a phase II trial, which also included patients with previous anthracycline-containing adjuvant regimens.

Advances in cell separation: recent developments in counterflow centrifugal elutriation and continuous flow cell separation

Cell separation by counterflow centrifugal elutriation (CCE) or free flow electrophoresis (FFE) is performed at lower frequency than cell cloning and antibody-dependent, magnetic or fluorescence-activated cell sorting. Nevertheless, numerous recent publications confirmed that these physical cell separation methods that do not include cell labeling or cell transformation steps, may be most useful for some applications. CCE and FFE have proved to be valuable tools, if homogeneous populations of normal healthy untransformed cells are required for answering scientific questions or for clinical transplantation and cells cannot be labeled by antibodies, because suitable antibodies are not available or because antibody binding to a cell surface would induce the cell reaction which should be investigated on purified cells or because antibodies bound to the surface hamper the use of the isolated cells. In addition, the methods are helpful for studying the biological reasons for, or effects of, changes in cell size and cellular negative surface charge density. Although the value of the methods was confirmed in recent years by a considerable number of important scientific results, activities to further develop and improve the instruments have, unfortunately, declined.

Increased high-density lipoprotein cholesterol in patients with epilepsy treated with carbamazepine: a gender-related study

PURPOSE

Long-term treatment with carbamazepine (CBZ) may alter serum lipoprotein concentrations. Gender-related examinations, however, are rare and inconsistent in their results.

METHODS

To examine possible sex differences, serum lipoproteins were analyzed in 127 clinic outpatients (56 women and 71 men) with epilepsies with focal or secondarily generalized tonic-clonic seizures (or both) treated with a CBZ monotherapy. Results were compared with a control group of 177 blood donors (67 women and 110 men) matched for age and weight.

RESULTS

Total cholesterol, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol were higher in both male and female patients treated with CBZ compared with controls. The known sex difference in serum lipoprotein concentrations (i.e., higher LDL cholesterol and triglycerides but lower HDL cholesterol in men) was confirmed in controls and patients treated with CBZ, with the exception of LDL cholesterol. The HDL as well as the LDL differences were significantly more pronounced in women treated with CBZ than in men when compared with their controls. These results were independent of the dose of CBZ and plasma concentrations. Lathosterol, a cholesterol precursor, and its ratio to cholesterol, an indicator of cholesterol synthesis, were not different, when compared between gender and different HDL groups.

CONCLUSIONS

The observed increase in HDL cholesterol in patients with CBZ, especially in women, might correlate with the previously reported diminished rate of death from coronary heart disease in patients with epilepsy as HDL exerts an antiatherogenic effect.

Antibodies against Helicobacter felis in sera of cats and dogs

Serum samples from 61 dogs and 49 cats were screened for circulating antibodies against Helicobacter felis by an enzyme-linked immunosorbent assay (ELISA) using sonicated bacteria as an antigen. To improve the specificity of the ELISA, sera were absorbed with Campylobacter jejuni subsp. jejuni H. pylori as well as H. felis. Sera from 26 dogs (43%) and 19 cats (39%) revealed clear positive absorbance readings determined as an optical density (OD) that was statistically significant above the OD mean value [P < 0.025 (one-tailed); log10]. The absorbance pattern of ELISA-positive sera corresponded to results obtained with bovine and human reference sera. Furthermore, a correlation between the immune response and results from histopathological examination of gastric specimens from 22 dogs was demonstrated. It could be shown that antibodies against H. felis in sera of cats and dogs can easily be detected using an ELISA. The diagnostic value of this test must be evaluated in further investigations.

A tumor necrosis factor-induced model of human primary demyelinating diseases develops in immunodeficient mice

We have reported previously that in the central nervous system (CNS) local expression of tumor necrosis factor (TNF) transgenes can trigger the development of oligodendrocyte apoptosis, primary inflammatory demyelination and neurological dysfunction, accompanied by lymphocyte and macrophage infiltration into the CNS. To distinguish between the local effects of transgene-encoded TNF and the potential encephalitogenic effects of immune infiltrates upon CNS disease pathogenesis, we have backcrossed Tg6074 TNF-transgenic mice to mice deficient in CD4, beta2-microglobulin (beta2m), immunoglobulin mu chain (Igmu) or recombination activation gene-1 (Rag-1). TNF was capable of triggering undiminished primary demyelination in all of the immunodeficient mice, in the presence of activated cells of the macrophage/microglial lineage. We conclude that TNF is sufficient to induce primary inflammatory demyelination and neurological deficits even in the absence of adaptive immunity.

Typing of clinical Mycobacterium avium complex strains cultured during a 2-year period in Denmark by using IS1245

In the present study restriction fragment length polymorphism analyses with the recently described insertion sequence IS1245 as a probe was performed with clinical Mycobacterium avium complex strains cultured in Denmark during a 2-year period. The overall aim of the study was to disclose potential routes of transmission of these microorganisms. As a first step, the genetic diversity among isolates from AIDS patients and non-human immunodeficiency virus (HIV)-infected patients was described. In addition, a number of isolates from nonhuman sources cultured during the same period were analyzed and compared to the human isolates. A total of 203 isolates from AIDS patients (n = 90), non-HIV-infected patients (n = 91), and nonhuman sources (n = 22) were analyzed. The presence of IS1245 was restricted to Mycobacterium avium subsp. avium isolates. The majority of human isolates had large numbers of IS1245 copies, while nonhuman isolates could be divided into a high-copy-number group and a low-copy-number group. Groups of identical strains were found to be geographically widespread, comprising strains from AIDS patients as well as strains from non-HIV-infected patients. Samples of peat (to be used as potting soil) and veterinary samples were found to contain viable M. avium isolates belonging to genotypes also found in humans.

Glutamate but not interleukin-6 influences the phosphorylation of tau in primary rat hippocampal neurons

Alzheimer's disease (AD) is characterized by amyloid plaques, neuritic degenerations, disturbed glutamatergic neurotransmission and a peculiar inflammatory response. Diffuse plaques develop into neuritic plaques when neurites undergo degeneration in the plaque area. Hyperphosphorylation of tau proteins is a major step in neuritic pathology. Interleukin-6 (IL-6) has been found in diffuse and neuritic amyloid plaques in AD. Therefore the question arises whether IL-6 is involved in the transformation of diffuse into neuritic plaques by affecting tau phosphorylation. We investigated the influence of glutamate and IL-6 on tau phosphorylation in cultured primary rat hippocampal neurons. Glutamate but not IL-6 induced a dephosphorylation of tau. Furthermore IL-6 did not influence the glutamate-induced dephoshorylation of tau. We conclude that the role of IL-6 in AD is not related to the phosphorylation of tau.

Advances in cell separation: recent developments in counterflow centrifugal elutriation and continuous flow cell separation

Cell separation by counterflow centrifugal elutriation (CCE) or free flow electrophoresis (FFE) is performed at lower frequency than cell cloning and antibody-dependent, magnetic or fluorescence-activated cell sorting. Nevertheless, numerous recent publications confirmed that these physical cell separation methods that do not include cell labeling or cell transformation steps, may be most useful for some applications. CCE and FFE have proved to be valuable tools, if homogeneous populations of normal healthy untransformed cells are required for answering scientific questions or for clinical transplantation and cells cannot be labeled by antibodies, because suitable antibodies are not available or because antibody binding to a cell surface would induce the cell reaction which should be investigated on purified cells or because antibodies bound to the surface hamper the use of the isolated cells. In addition, the methods are helpful for studying the biological reasons for, or effects of, changes in cell size and cellular negative surface charge density. Although the value of the methods was confirmed in recent years by a considerable number of important scientific results, activities to further develop and improve the instruments have, unfortunately, declined.

Separation of plant membranes by electromigration techniques

The review focuses on the multiple separating regimes that offers the free flow electrophoresis technique: free flow zone electrophoresis, isoelectric focusing, isotachophoresis, free flow step electrophoresis. Also, the feasibility to apply either interval or continuous flow electrophoresis is evaluated. The free flow zone electrophoresis regime is generally selected for the separation of cells, organelles and membranes while the other regimes find their largest fields of applications in the purification of proteins and peptides. The latter regimes present the highest resolution efficiency. Therefore, a large part of this review is devoted to the applicabilities of these different regimes to the purification of organelles and membrane vesicles at the preparative scale. Recent developments, both in instrumentation and procedures, are described. The major achievements in plant membrane fractionation obtained with free flow electrophoresis are outlined. The related procedures are both analytical and preparative: they separate tonoplast and plasma membrane simultaneously from the same homogenate, they discriminate for one type of membrane vesicles of opposite orientation, and process large quantities of membrane material by reason of the continuous flow mode. Recent advances using electromigration techniques that permit confirmation of the dynamic state of membranes, characterisation of complex membrane-dependent functions and discovery of new membrane-localised activities are presented.