The adhesive properties of recombinant soluble L-selectin are modulated by its glycosylation

The leukocyte adhesion molecule L-selectin, which mediates the initial steps of leukocyte attachment to vascular endothelium, is intensely glycosylated. Different glycoforms of L-selectin are expressed on different leukocyte subsets and differences in L-selectin glycosylation appear to be correlated with the leukocyte's ability to attach to different endothelial targets. In the present study we addressed the question whether glycosylation of L-selectin influences L-selectin-ligand interactions. To obtain different glycoforms of L-selectin, recombinant proteins were expressed both in the baby hamster kidney (BHK) cell line and in the human myelogenous cell line K562, resulting in sL-sel[BHK] or sL-sel[K562], respectively. The glycosylation characteristics of the purified proteins were determined. The most striking differences in glycosylation were seen in the terminal sialylation. Each of the two proteins carried sialic acids in the alpha 2-3 position, while alpha 2-6-bound sialic acids were found exclusively on sL-sel[K562]. To investigate their adhesive properties, both recombinant sL-selectins were used in cell adhesion assays and interactions with the ligands present on various hematopoietic cell lines or activated human cardiac microvascular endothelial cells were examined. The binding capacity of sL-sel[K562] was about 1.6 fold higher compared to sL-sel[BHK] under static as well as under flow conditions. These findings indicate that the terminal sialylation pattern of L-selectin modulates its binding characteristics.

The fate of desmosomal proteins in apoptotic cells

Activation of caspases results in the disruption of structural and signaling networks in apoptotic cells. Recent biochemical and cell biological studies have shown that components of the cadherin-catenin adhesion complex in epithelial adherens junctions are targeted by caspases during apoptosis. In epithelial cells, desmosomes represent a second type of anchoring junctions mediating strong cell-cell contacts. Using antibodies directed against a set of desmosomal proteins, we show that desmosomes are proteolytically targeted during apoptosis. Desmogleins and desmocollins, representing desmosome-specific members of the cadherin superfamily of cell adhesion molecules, are specifically cleaved after onset of apoptosis. Similar to E-cadherin, the desmoglein-3 cytoplasmic tail is cleaved by caspases. In addition the extracellular domains of desmoglein-3 and desmocollin-3 are released from the cell surface by a metalloproteinase activity. In the presence of caspase and/or metalloproteinase inhibitors, both cleavage reactions are almost completely inhibited. As reported previously, the desmosomal plaque protein plakoglobin is cleaved by caspase-3 during apoptosis. Our studies now show that plakophilin-1 and two other major plaque proteins, desmoplakin-1 and -2, are also cleaved by caspases. Immunofluorescence analysis confirmed that this cleavage results in the disruption of the desmosome structure and thus contributes to cell rounding and disintegration of the intermediate filament system.

Determination of optimal non-denaturing elution conditions from affinity columns by a solid-phase screen

The purification of biological macromolecules by affinity chromatography is a widespread technique used to separate a protein from other biological components. However, this method may destroy the protein's physiological activity because elution conditions aimed to dissociate the protein of interest from the high-affinity matrix often irreversibly denature it. In the present work, we have developed a solid-phase assay to determine the optimal elution conditions for any buffer (in two steps) by determining (i) the lowest buffer concentration yielding maximum dissociation from the immobilized component and (ii) the highest buffer concentration that can be used without the loss of the protein's binding activity. Any buffer that can be reasonably used between these defined concentrations is suitable for elution within this interval. The screen is easily performed within a few hours and only requires nanograms to a few micrograms of protein. As an example, we demonstrate that more than 95% of the human transferrin receptor bound to a transferrin-sepharose ligand affinity column can be eluted with full binding activity at KSCN concentrations between 232 and 414 nM, whereas elution with urea is not suitable to purify fully functional protein.

[Repetitive transcranial magnetic stimulation (rTMS) in the acute and long-term therapy of refractory depression--a case report]

We report on a patient with therapy-resistant major depression according to DSM-IV criteria who has been hospitalized for 60 months during the last 7 years. Not even five electroconvulsive therapy (ECT) series (61 single applications) brought lasting remission of symptoms. As cognitive deficits developed and prolonged postnarcotic recovery times were observed, further ECT was contraindicated. The left frontal cortex was chosen as the target site for repetitive transcranial magnetic stimulation (rTMS) treatment. For identification, a neuronavigational system was used that allows online monitoring of the position of the magnetic coil in relation to the individual cortex. The therapeutic progress was monitored by standardized psychiatric ratings (HAMD, BDI). In addition, cognitive performance was tested during the course of treatment. Only a few rTMS applications already caused an obvious brightening in mood, remission of depressive delusional symptoms, and an increase in personal interests and activities. After 4 weeks of daily treatment, the patient was discharged from the ward. The rTMS treatments and psychotherapeutic counseling have been continued on an outpatient basis. Thus, pharmaco- and psychotherapeutic interventions combined with rTMS led to persistent symptom remission and social reintegration.

Shed L-selectin (sCD62L) load in trauma patients

BACKGROUND

Low circulating plasma concentrations of the leukocyte adhesion molecule L-selectin (sCD62L) were found to be associated with an increased risk for subsequent lung failure and case fatality after severe trauma. The objective of this study was to determine the robustness of soluble L-selectin, correcting for a broad spectrum of physiological variables.

METHODS

Patients with suspected multiple and/or trunk injuries were enrolled into this study over a 1-year period. Plasma samples were obtained on hospital presentation, and circulating soluble L-selectin was measured with a commercially available ELISA kit. Study records comprised all relevant clinical and laboratory data. Thirty-day survival rate, subsequent acute lung failure, and nosocomial pneumonia were defined as study endpoints. Statistical analysis was performed using multivariate logistic regression models.

RESULTS

Seventy patients with a mean age of 35.51 years (range, 10-87 years) and a mean ISS score of 36.61 (95% CI, 31.08-42.14) entered the study. Eleven patients died, leading to an attributable mortality of 15.70%. L-Selectin levels did not differ between survivors and nonsurvivors. Five patients progressed to acute lung injury, whereas 11 patients developed hospital-acquired pneumonia. Lower L-selectin levels indicated patients at risk for lung injury with a relative odds estimated at 4.43 (P = 0.017). Statistical significance diminished in the multivariate model. In contrast, plasma concentrations of circulating sCD62L were significantly decreased in patients developing nosocomial pneumonia (P = 0.023), with a twofold increased relative odds (OR, 1.96; 95% CI, 0.51-7.50). No effect modification was observed by the included covariables.

CONCLUSIONS

The results of this study highlight the independent predictive value of initially decreased soluble L-selectin levels for the identification of patients susceptible to subsequent respiratory complications after severe trauma.

LI-cadherin gene expression during mouse intestinal development

LI-cadherin (Liver-Intestine cadherin) is a member of a subclass (7-D cadherins) within the cadherin superfamily. Although its cellular function as a cell-cell adhesion molecule has been demonstrated in cell culture studies, its physiological function still needs to be explored in the intact organism. After isolating the cDNA for mouse LI-cadherin, we generated specific antibodies against the overexpressed protein and studied its expression pattern in adult mouse tissues and mouse embryos. The mouse LI-cadherin sequence is 91% identical to the sequence of rat LI-cadherin and exhibits the same structural features described for rat LI-cadherin. In mouse adult tissue, LI-cadherin is expressed in the intestine and in small amounts in the spleen. In contrast to rat, Mouse LI-cadherin was not expressed in liver. During mouse embryogenesis, LI-cadherin expression begins at embryonic day 12.5. With the exception of transient expression in the urogenital sinus and the common bile duct on day 13.5, LI-cadherin was found exclusively in the intestinal epithelium. Its expression coincides with the formation of intestinal villi, a developmental stage that includes major tissue remodeling, growth, and differentiation. LI-cadherin is expressed along the entire anterior-posterior axis of the developing intestine as well as along the entire villus axis once villi begin to form. LI-cadherin occupies all cell surfaces of the deeper layers of the epithelium, distributing to basolateral surfaces only in the cells of the outer epithelial layer. LI-cadherin was found to be always co-expressed with E-cadherin.

Development of a novel molecular adapter for the optimization of immunotoxins

Immunotoxins consisting of catalytic domains of natural toxins and tumor-specific ligands were modified by introducing a molecular adapter that is able to transport the toxic domain more efficiently into cells. The adapter is a three-component structure: its core is a membrane transfer sequence (MTS) flanked by two different cleavable sequences. The directed and irreversible cellular uptake of the construct is driven by either enzymatic or chemical cleavage of the two flanking sequences. In our studies, the purified A-chain of diphtheria toxin (DT) was coupled to two different MTSs via disulfide bonds. A cytotoxicity assay revealed that the constructs containing the MTSs were more potent than DT A-chain alone and that the disulfide bond was cleaved.

LI-cadherin: a marker of gastric metaplasia and neoplasia

BACKGROUND

Intestinal metaplasia is considered a risk factor for the development of gastric adenocarcinomas of the intestinal type and is found in approximately 20% of gastric biopsies. Conventional histology only detects advanced stages of intestinal metaplasia.

AIMS

To study expression of the enterocyte specific adhesion molecule liver-intestinal (LI)-cadherin in intestinal metaplasia as well as in gastric cancer, and to evaluate its use as a diagnostic marker molecule.

PATIENTS

Gastric biopsies (n=77) from 30 consecutive patients (n=30; aged 28-90 years) as well as surgically resected tissue samples (n=24) of all types of gastric carcinomas were analysed.

METHODS

Single and double label immunofluorescence detection on cryosections of gastric biopsies; alkaline phosphatase antialkaline phosphatase method on paraffin embedded carcinoma tissue sections.

RESULTS

Of 77 biopsies (from 30 patients), 12 (from 10 patients) stained positive for LI-cadherin. LI-cadherin staining correlated with the presence of intestinal metaplasia. Conventional histological diagnosis however failed to detect subtle gastric intestinal metaplasia (three of 10 patients). In contrast, only LI-cadherin and villin were positive in these cases whereas sucrase-isomaltase also failed to detect intestinal metaplasia in four of 10 patients. Well differentiated gastric carcinomas showed intense staining for LI-cadherin while undifferentiated carcinomas showed only weak diffuse cytoplasmic staining.

CONCLUSIONS

To detect early metaplastic changes in the gastric mucosa, LI-cadherin has a sensitivity superior to sucrase-isomaltase and conventional histology and comparable with that of villin. Its specificity exceeds that of villin. Thus LI-cadherin represents a new, reliable, and powerful marker molecule for early detection of gastric intestinal metaplasia and well differentiated adenocarcinomas.

LI-cadherin: a marker of gastric metaplasia and neoplasia

BACKGROUND

Intestinal metaplasia is considered a risk factor for the development of gastric adenocarcinomas of the intestinal type and is found in approximately 20% of gastric biopsies. Conventional histology only detects advanced stages of intestinal metaplasia.

AIMS

To study expression of the enterocyte specific adhesion molecule liver-intestinal (LI)-cadherin in intestinal metaplasia as well as in gastric cancer, and to evaluate its use as a diagnostic marker molecule.

PATIENTS

Gastric biopsies (n=77) from 30 consecutive patients (n=30; aged 28-90 years) as well as surgically resected tissue samples (n=24) of all types of gastric carcinomas were analysed.

METHODS

Single and double label immunofluorescence detection on cryosections of gastric biopsies; alkaline phosphatase antialkaline phosphatase method on paraffin embedded carcinoma tissue sections.

RESULTS

Of 77 biopsies (from 30 patients), 12 (from 10 patients) stained positive for LI-cadherin. LI-cadherin staining correlated with the presence of intestinal metaplasia. Conventional histological diagnosis however failed to detect subtle gastric intestinal metaplasia (three of 10 patients). In contrast, only LI-cadherin and villin were positive in these cases whereas sucrase-isomaltase also failed to detect intestinal metaplasia in four of 10 patients. Well differentiated gastric carcinomas showed intense staining for LI-cadherin while undifferentiated carcinomas showed only weak diffuse cytoplasmic staining.

CONCLUSIONS

To detect early metaplastic changes in the gastric mucosa, LI-cadherin has a sensitivity superior to sucrase-isomaltase and conventional histology and comparable with that of villin. Its specificity exceeds that of villin. Thus LI-cadherin represents a new, reliable, and powerful marker molecule for early detection of gastric intestinal metaplasia and well differentiated adenocarcinomas.

The independent living skills survey: a comprehensive measure of the community functioning of severely and persistently mentally ill individuals

The research reported in this article investigated the psychometric characteristics of the Independent Living Skills Survey (ILSS), a comprehensive, objective, performance-focused, easy-to-administer measure of the basic functional living skills of individuals with severe and persistent mental illness (SPMI). Two versions were developed, one for informants and one for self-report. Data from three research projects were analyzed to determine the versions' internal consistency, stability, interrater reliability, sensitivity to the effects of skills training, and concurrent and predictive validity. The results indicated that the two versions have acceptable psychometric characteristics, and suggestions are offered for their use in planning individualized treatment, evaluating programmatic services, and determining eligibility for benefits.

Intestinal cell adhesion molecules. Liver-intestine cadherin

The cadherin superfamily comprises a large number of cell adhesion molecules, several of which are expressed in the gastrointestinal tract. LI-cadherin represents a novel type of cadherin within the cadherin superfamily distinguished from other cadherins by structural and functional features described in this review. In the mouse and human, LI-cadherin is selectively expressed on the basolateral surface of enterocytes and goblet cells in the small and large intestine, whereas in the rat this cadherin is additionally detectable in hepatocytes. LI-cadherin is capable of mediating Ca(2+)-dependent homophilic cell-cell adhesion independent of interactions with the cytoskeleton, indicating that the adhesive function of this novel cadherin is complementary to that of E-cadherin and desmosomal cadherins co expressed in the intestinal mucosa.

Cleavage and shedding of E-cadherin after induction of apoptosis

Apoptotic cell death induces dramatic molecular changes in cells, becoming apparent on the structural level as membrane blebbing, condensation of the cytoplasm and nucleus, and loss of cell-cell contacts. The activation of caspases is one of the fundamental steps during programmed cell death. Here we report a detailed analysis of the fate of the Ca(2+)-dependent cell adhesion molecule E-cadherin in apoptotic epithelial cells and show that during apoptosis fragments of E-cadherin with apparent molecular masses of 24, 29, and 84 kDa are generated by two distinct proteolytic activities. In addition to a caspase-3-mediated cleavage releasing the cytoplasmic domain of E-cadherin, a metalloproteinase sheds the extracellular domain from the cell surface during apoptosis. Immunofluorescence analysis confirmed that concomitant with the disappearance of E-cadherin staining at the cell surface, the E-cadherin cytoplasmic domain accumulates in the cytosol. In the presence of inhibitors of caspase-3 and/or metalloproteinases, cleavage of E-cadherin was almost completely blocked. The simultaneous cleavage of the intracellular and extracellular domains of E-cadherin may provide a highly efficient mechanism to disrupt cadherin-mediated cell-cell contacts in apoptotic cells, a prerequisite for cell rounding and exit from the epithelium.

Structural and Functional Stability of the Mature Transferrin Receptor from Human Placenta

The transferrin receptor (TfR) is a N- and O-glycosylated transmembrane protein mediating the cellular iron uptake by binding and internalization of diferric transferrin. In this study, rate constants and dissociation constants of 125I-ferri-transferrin binding to the human TfR were examined dependent on receptor glycan composition, pH, bivalent cations, and temperature. To do so, purified human placental TfR was noncovalently immobilized to polystyrene surfaces and subjected to alterations in various parameters. We found that transferrin binding was clearly dependent on a receptor pretreatment with buffers of various pH in that most of the TfR molecules irreversibly lost transferrin binding activity below pH 6.5. However, the dissociation constant of the remaining active binding sites was not affected. Similarly, we were able to define the thermal stability of the receptor as a function of transferrin binding ability. Binding of transferrin was completely lost provided that the receptor was pretreated at temperatures of at least 65 degrees C. Treatment with EDTA also caused an irreversible loss of transferrin binding activity, indicating that the functionally active conformation of the mature TfR depends on bivalent cations. In order to examine the role of the receptor glycans, we enzymatically removed the sialic acid residues, the hybrid and oligomannosidic N-glycans, or all types of N-glycans. In contrast to the parameters described above, all desialylated and N-deglycosylated TfR variants had exactly the same transferrin binding properties as the native TfR. To assess changes in the secondary structure of the receptor, circular dichroic spectra were recorded from TfR at pH 5.0, from heat pretreated receptor and from deglycosylated TfR. Since the receptor did not exhibit detectable changes in the CD spectrum of the deglycosylated receptor, it can be concluded that the N-linked carbohydrates of the mature, fully processed TfR are not essential for transferrin binding and conformational stability.

Intestinal cell adhesion molecules. Liver-intestine cadherin

The cadherin superfamily comprises a large number of cell adhesion molecules, several of which are expressed in the gastrointestinal tract. LI-cadherin represents a novel type of cadherin within the cadherin superfamily distinguished from other cadherins by structural and functional features described in this review. In the mouse and human, LI-cadherin is selectively expressed on the basolateral surface of enterocytes and goblet cells in the small and large intestine, whereas in the rat this cadherin is additionally detectable in hepatocytes. LI-cadherin is capable of mediating Ca(2+)-dependent homophilic cell-cell adhesion independent of interactions with the cytoskeleton, indicating that the adhesive function of this novel cadherin is complementary to that of E-cadherin and desmosomal cadherins co expressed in the intestinal mucosa.

Enlisting indigenous community supporters in skills training programs for persons with severe mental illness

OBJECTIVE

This study evaluated the generalization of skills training for severely and persistently mentally ill individuals who were paired with indigenous supporters. The supporters monitored the individuals' environments and prompted them to use their skills.

METHODS

A total of 85 individuals with severe and persistent mental illness received six months of skills training. Forty-five of the participants received support from an individual of their choosing. The other 40 participants did not have supporters. At the end of the six-month skills training period, the supporters' participation was officially terminated, although they were encouraged to remain in their role for as long as both parties felt comfortable. The effects of the support were measured in terms of interpersonal functioning, acquisition and retention of the skills, psychopathology, global functioning, and satisfaction. Several process measures were also collected.

RESULTS

The support procedures were evaluated favorably by both patients and supporters. The interpersonal functioning of the group with supporters was found to be significantly better than that of the nonsupported group at six- and 12-month follow-ups. No differences were found between the groups in symptoms-which were minimal during the entire training period-or skills learning and retention.

CONCLUSIONS

The effects of support are likely applicable for a variety of individuals, supporters, and facilities. Indirect evidence suggested the importance of providing support for the supporters.

[Continent cutaneous urinary diversion of ileal neobladders by transverse tubularized ileum segments (Yang- or Monti-principle)]

The method using transvers retubularized segment of ileum as an efferent conduit in Hautmann's neobladder is easy to perform and it can be repeated in revision procedures. We performed the procedure in nine patients who underwent radical cystectomy. At 8-16 months after operation, the resulting stomas were easy to catheterize. Of the nine patients, eight were continent. We find the procedure to be a good alternative when the appendix is absent and a cutaneous stoma is needed. It could be the preferred method in ileal neobladders with cutaneous outlet.

Carbohydrate structures of soluble human L-selectin recombinantly expressed in baby-hamster kidney cells

A soluble form of L-selectin was recombinantly produced, which might be an effective therapeutic agent in inflammatory disorders, acting as an inhibitor for leucocyte endothelium adhesion. In the present study the oligosaccharide structures of soluble human L-selectin, recombinantly expressed in baby-hamster kidney cells, were determined. The N-linked glycans were enzymically released and fluorescently labelled with 2-aminobenzamide. Sialylation of the N-glycans was analysed by anion-exchange chromatography followed by rechromatography of the resulting fractions on amino-phase HPLC after release of the sialic acid residues. Desialylated oligosaccharides were separated using two-dimensional HPLC and characterized by digestion with exoglycosidases and MS. More than 30 oligosaccharide structures representing at least 95% of the overall glycosylation of this protein were determined. The results revealed that recombinant soluble human L-selectin carries bi-, tri- and tetra-antennary sugar chains, which are fucosylated on the innermost residue of N-acetylglucosamine. The number of sialic acid residues linked to these glycans ranges from 0 (neutral glycans) to 4 (tetrasialylated oligosaccharides). The sialic acid is found exclusively in the alpha 2-3 linkage to galactose. In addition to the main glycans, different minor structures containing terminal N-acetylgalactosamine, or the H (O) blood-group determinant were also identified. O-Glycosylation of mucin-type sugar chains was not detected in recombinant soluble human L-selectin.

Sialoforms of dipeptidylpeptidase IV from rat kidney and liver

Dipeptidylpeptidase IV (DPP IV, CD26), a serine-type exo- and endopeptidase found in the cell surface membrane of many tissues, was employed as a model membrane glycoprotein to study the expression of sialoforms on cell surface glycoproteins. Native, enzymatically active DPP IV was purified from plasma membranes of kidney and liver by lectin affinity chromatography in conjunction with crown ether anion exchange chromatography. The enzyme was gradient-eluted in continuous fractions, all showing a single polypeptide band of about 100 kDa when separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing, denaturing conditions. Analysis of the purified DPP IV by isoelectric focusing (IEF) showed that it consists of several polypeptides of different isoelectric points (IP) ranging from 5.5 to 7.0. In vitro- desialylation of the enzyme and subsequent isoelectric focusing revealed that the differences in isoelectric points were due to differences in the degree of sialylation. Differences in the degree of sialylation between the fractions were also demonstrated by SDS-PAGE under nonreducing and nondenaturing conditions. Increased sialylation of the enzyme as demonstrated by isoelectric focusing resulted in increased migration velocity in nonreducing and nondenaturing SDS-polyacrylamide gels. In vitro -desialylation of the enzyme and its resialylation confirmed that sialylation was responsible for this extraordinary migration behavior. The native enzyme was predominantly sialylated via alpha 2, 6-linkage, as shown by lectin affinity blotting employing Sambucus nigra agglutinin (SNA) and Maackia amurensis agglutinin (MAA). These findings demonstrate that a distinct membrane glycoprotein may exist in various sialoforms, distinguished from each other by a different number of sialic acid residues. Moreover, these sialoforms can be individually purified by crown ether anion exchange chromatography.

Nephrotoxic and peroxidative potential of meropenem and imipenem/cilastatin in rat and human renal cortical slices and microsomes

BACKGROUND

Carbapenems are a relatively new class of beta-lactam antibiotics characterized by a broad spectrum of antibacterial activity. Meropenem (MER), a new carbapenem has shown a lower nephrotoxic potential compared to imipenem (IMI). IMI is used in a fixed one-to-one combination with the nephroprotective agent cilastatin (CIL). The present studies examined whether MER and IMI/CIL produce peroxidative and nephrotoxic alterations including oxidative changes in rat and human renal cortical slices and microsomes.

MATERIALS AND METHODS

Untreated slices and microsomes were incubated in vitro for various periods of time in phosphate-buffered media containing various concentrations of MER, IMI/CIL or for comparison cephaloridine (CPH). Lipid peroxidation was monitored by the determination of malondialdehyde (MDA) in incubation media and slices in the presence or absence of antioxidants. Total glutathione, oxidized glutathione (GSSG), pyruvate-stimulated gluconeogenesis and paraaminohippurate (PAH) accumulation were measured in slices.

RESULTS

In rat renal cortical slices, MER, IMI/CIL and CPH induced a time- and concentration-dependent MDA production (content in incubation media plus slices). 5 mM MER, 5 mM IMI/CIL and 3 mM CPH were the lowest concentrations which caused a significant MDA production after 3 hs compared to control (control 61.5+/-15.3 nmol MDA/g tissue, MER 75.4+/-10.9, p<0.001; control 48.0+/-8.7, IMI/CIL 65.1+/-11.7, p<0.001; control 61.5+/-15.3, CPH 113.0+/-28.2, p<0.001). 20 mM MER, 20 mM IMI/CIL and 12 mM CPH revealed marked MDA production after 3 hs in human renal cortical slices (control 29.8+/-4.2 nmol MDA/g tissue, MER 49.4+/-8.7, p<0.01; control 27.6+/-7.0, IMI/CIL 68.3+/-9.9, p<0.001; control 32.5+/-7.7, CPH 93.8+/-31.6, p<0.001) and in human renal microsomes (control 1.0+/-0.9 nmol MDA/mg protein, MER 2.9+/-1.0, p<0.05; IMI/CIL 6.8+/-2.2, p<0.001; CPH 8.4+/-2.2, p<0.001), respectively. The corresponding MDA production was about 2-fold higher in rat renal cortical slices and almost the same in rat renal microsomes. Antioxidants reduced the MER-induced increase in MDA content in rat renal cortical slices by 48% (alpha-tocopherol, 10(-4) M), 72% ((+)-cyanidanol-3, 10(-5) M) and 100% (DPPD, N, N'-diphenyl-p-phenylendiamine, 10(-6) M). In rat renal cortical slices, MER and IMI/CIL induced an increase up to 50% in the content of GSSG and a corresponding %-decrease in reduced glutathione (GSH). In rat renal cortical slices, MER and IMI/CIL induced a time- and concentration-dependent decrease in PAH accumulation and gluconeogenesis. PAH accumulation was already reduced by 5 mM MER after 1 h (control slice to medium ratio 18.3+/-6.8, MER 10.7+/-1.9, p<0.05) and by 10 mM IMI/CIL after 3 h (control 16.9+/-5.6, IMI/CIL 5.5+/-1.3, p<0.001). Pyruvate-stimulated gluconeogenesis after 3 hs was already reduced by 2.5 mM MER (control 5.7+/-2.1 micromol glucose/g tissue/h, MER 3.9+/-1.1, p<0.05) and by 10 mM IMI/CIL (control 5.7+/-2.1, IMI/CIL 2.8+/-1.0, p<0.001).

CONCLUSION

Thus, MER and IMI/CIL (at concentrations more than 10-fold higher as peak plasma concentrations achieved in humans) revealed an oxidative change (depletion of GSH, production of GSSG), a peroxidative potential (production of MDA) and a nephrotoxic potential (reduction in pyruvate-stimulated gluconeogenesis and PAH accumulation). Human kidney seems to be less susceptible to beta-lactam antibiotic-induced lipid peroxidation than rat kidney.

H (0) blood group determinant is present on soluble human L-selectin expressed in BHK-cells

In the present study we show that the H (0) blood group determinant Fuc alpha1-2Gal beta1-4GlcNAc beta1-R is present on N-linked glycans of soluble human L-selectin recombinantly expressed in baby hamster kidney (BHK) cells. The glycans were isolated using complementary HPLC techniques and characterized by a combination of exoglycosidase digestion and mass spectrometry. The linkage of the fucose residues was determined by incubation of the glycans with specific fucosidases. The H blood determinant Fuc alpha1-2Gal beta1-4GlcNAc beta1 was detected for bi-, 2,4 branched tri- and tetraantennary structures. To our knowledge, the proposed oligosaccharide structures represent a new glycosylation motif for recombinant glycoproteins expressed on BHK cells.

Characterization of a soluble class I alpha-mannosidase in human serum

Class I alpha-mannosidases are thought to exist exclusively as integral membrane proteins that play intracellulary an essential role in the N-glycan biosynthesis. Using [3H]Man9GlcNAc2 as a substrate, we were able to identify a soluble alpha-mannosidase in human serum that trims the substrate Man9GlcNAc2 to Man(5-8)GlcNAc2 with Man6GlcNAc2 being the major product. This serum mannosidase is Ca2+-dependent, sensitive to 1-deoxymannojirimycin but insensitive to the class II inhibitor swainsonine and, hence, belongs to class I mannosidases. The enzymatic properties of the serum class I mannosidase are similar to that of the membrane bound class I mannosidases Golgi-mannosidase IA and IB and Man9-mannosidase.

Structural model of phospholipid-reconstituted human transferrin receptor derived by electron microscopy

BACKGROUND

The transferrin receptor (TfR) regulates the cellular uptake of serum iron. Although the TfR serves as a model system for endocytosis receptors, neither crystal structure analysis nor electron microscopy has yet revealed the molecular dimensions of the TfR. To derive the first molecular model, we analyzed purified, lipid-reconstituted human TfR by high-resolution electron microscopy.

RESULTS

A structural model of phospholipid-reconstituted TfR was derived from 72 cryo-electron microscopic images. The TfR dimer consists of a large extracellular globular domain (6.4 x 7.5 x 10.5 nm) separated from the membrane by a thin molecular stalk (2.9 nm). A comparative protein sequence analysis suggests that the stalk corresponds to amino acid residues 89-126. Under phospholipid-reconstitution conditions, the human TfR not only integrates into vesicles, but also forms rosette-like structures called proteoparticles. Scanning transmission electron microscopy revealed an overall diameter of 31.5 nm and a molecular mass of 1669 +/- 26 kDa for the proteoparticles, corresponding to nine TfR dimers. The average mass of a single receptor dimer was determined as being 186 +/- 4 kDa.

CONCLUSIONS

Proteoparticles resemble TfR exosomes that are expelled by sheep reticulocytes upon maturation. The structure of proteoparticles in vitro is thus interpreted as being the result of the TfR's strong self-association potential, which might facilitate the endosomal sequestration of the TfR away from other membrane proteins and its subsequent return to the cell surface within tubular structures. The stalk is assumed to facilitate the tight packing of receptor molecules in coated pits and recycling tubuli.

p53 mutagenesis in Klatskin tumors

Mutagenesis of the p53 tumor-suppressor gene represents the most common genetic alteration in human malignancies but has not yet been investigated in Klatskin tumors. Cancerous and normal liver tissues were obtained from 12 patients after surgical resection of Klatsin tumors. Genomic DNA was extracted and served as a template for PCR amplification and sequencing of a 1,574-bp fragment of the p53 gene comprising the exons 5 through 8. Immunohistochemical expression analysis was performed using five different antibodies. Missense mutations were detected in 2 of 12 patients--one transversion on codon 273 (Arg --> Leu) and a transition on codon 168 (His --> Arg). In all specimens, immunohistochemistry was negative regarding a nuclear overexpression. An apparent clinicopathologic impact of p53 mutations was not observed. This report on mutagenesis of the p53 gene in Klatskin tumors shows that the most commonly mutated tumor suppressor gene in human cancers is also mutated in a subset of patients with Klatskin tumors. Assessment of a clinical or pathological impact of p53 mutagenesis on Klatskin tumors requires evaluation in larger studies.

[The physician as manager--medical department coordination as a reaction to changed responsibilities]

As a reaction to the changing situation in the public health service, we have changed a senior house officer post into a job for medical management out off our own motivation. In the sense of job sharing, the department has now got an expert with medical competence for the new business. He is the connecting link between the department and the administration of the hospital.

Cell surface glycoproteins undergo postbiosynthetic modification of their N-glycans by stepwise demannosylation

Primary rat hepatocytes and two hepatoma cell lines have been used to study whether high mannose-type N-glycans of plasma membrane glycoproteins may be modified by the removal of mannose residues even after transport to the cell surface. To examine glycan remodeling of cell surface glycoproteins, high mannose-type glycoforms were generated by adding the reversible mannosidase I inhibitor deoxymannojirimycin during metabolic labeling with [3H]mannose, thereby preventing further processing of high mannose-type N-glycans to complex structures. Upon transport to the cell surface, glycoproteins were additionally labeled with sulfosuccinimidyl-2-(biotinamido)ethyl-1,3-dithiopropionate. This strategy allowed us to follow selectively the fate of cell surface glycoproteins. Postbiosynthetic demannosylation was monitored by determining the conversion of Man8-9GlcNAc2 to smaller structures during reculture of cells in the absence of deoxymannojirimycin. The results show that high mannose-type N-glycans of selected cell surface glycoproteins are trimmed from Man8-9GlcNAc2 to Man5GlcNAc2 with Man7GlcNAc2 and Man6GlcNAc2 formed as intermediates. It could be clearly shown in MH 7777 as well as in HepG2 cells that demannosylation affects plasma membrane glycoproteins after they are routed to the cell surface. As was determined for total cell surface glycoproteins in HepG2 cells, this process occurs with a half-time of 6.7 h. By analyzing the size of high mannose-type glycans of glycoproteins isolated from the cell surface at the end of the reculture period, i.e. after trimming had occurred, we were able to demonstrate that glycoproteins carrying trimmed high mannose glycans become exposed at the cell surface. From these data we conclude that cell surface glycoproteins can be trimmed by mannosidases at sites peripheral to N-acetylglucosaminyltransferase I without further processing of their glycans to the complex form. This glycan remodeling may occur at the cell surface or during endocytosis and recycling back to the cell surface.

p53 hot-spot mutational analysis in advanced Western gallbladder carcinoma

In gallbladder carcinoma, studies on the prime target of genetic alterations and gene therapy in human gallbladder malignancies, the p53 tumor suppressor gene, have been focusing on this gene's immunohistochemical detection. From November 1991 to October 1993, seven patients suffering from gallbladder carcinoma underwent surgical resection. Cancerous and normal liver tissues were obtained immediately after surgery, snap-frozen in liquid nitrogen, and stored at -80 degrees C for immunohistochemistry and DNA isolation. Exons 5, 6, 7, and 8 of the p53 gene were completely sequenced following polymerase chain reaction (PCR) amplification of a 1574-bp fragment. Missense mutations were detected in the cancerous tissues of two patients: one transition each on codons 134 (Phe-->Leu) and 146 (Trp-->Arg). Immunohistochemical p53 staining was positive in the latter patient only. This is the first report on sequence analysis and mutagenesis of the p53 gene in Caucasian patients with gallbladder cancer. Both mutations were transitions and seem to represent a rather rare event. The possible impact of p53 mutagenesis on gallbladder tumorigenesis requires evaluation in larger studies.

Angioarchitecture of the human spermatic cord

Human spermatic cords were investigated by means of cast preparations, light-microscopic examination and computer-aided 3-dimensional reconstructions from serial sections of paraffin-embedded material. After leaving the testis, the testicular veins formed two principal groups co-existing side by side. Numerous veno-venous anastomoses could be observed within each individual group, whereas only a few mutual intergroup anastomoses were found. The testicular artery ran within one group but showed no close topographical relationship to the other group. Light microscopy of the serial sections revealed that the group of veins with no close topographical relationship to the testicular artery ran at a distance of several centimeters embedded within fatty tissue. With the help of computer-aided 3-dimensional reconstructions, a spatial picture of the vascular organization was obtained. These results allowed the following classification of the veins of the pampiniform plexus. Group-I veins formed a tight plexus around the testicular artery by means of veno-venous anastomoses. Group-II veins formed veno-venous anastomoses between each other and ran over at a sizeable distance embedded in fatty tissue but showed no close topographical relationship to the testicular artery. Group-III vessels formed veno-venous anastomoses between group-I and group-II. Group IV veins formed arterio-venous anastomoses with the testicular artery. Based on the differences in wall structure and diameter, a subclassification in group-I and group-II was undertaken. This organization of the veins of the human pampiniform plexus should further the understanding of physiological processes, such as the transfer of hormones and other substances from the veins to the testicular artery and vice versa. It should also facilitate the tracing of the veins during antegrade sclerosing.

LI-cadherin-mediated cell-cell adhesion does not require cytoplasmic interactions

The adhesive function of classical cadherins depends on the association with cytoplasmic proteins, termed catenins, which serve as a link between cadherins and the actin cytoskeleton. LI-cadherin, a structurally different member of the cadherin family, mediates Ca2+-dependent cell-cell adhesion, although its markedly short cytoplasmic domain exhibits no homology to this highly conserved region of classical cadherins. We now examined whether the adhesive function of LI-cadherin depends on the interaction with catenins, the actin cytoskeleton or other cytoplasmic components. In contrast to classical cadherins, LI-cadherin, when expressed in mouse L cells, was neither associated with catenins nor did it induce an upregulation of beta-catenin. Consistent with these findings, LI-cadherin was not resistant to detergent extraction and did not induce a reorganization of the actin cytoskeleton. However, LI-cadherin was still able to mediate Ca2+-dependent cell-cell adhesion. To analyze whether this function requires any interaction with proteins other than catenins, a glycosyl phosphatidylinositol-anchored form of LI-cadherin (LI-cadherin(GPI)) was constructed and expressed in Drosophila S2 cells. The mutant protein was able to induce Ca2+-dependent, homophilic cell-cell adhesion, and its adhesive properties were indistinguishable from those of wild type LI-cadherin. These findings indicate that the adhesive function of LI-cadherin is independent of any interaction with cytoplasmic components, and consequently should not be sensitive to regulatory mechanisms affecting the binding of classical cadherins to catenins and to the cytoskeleton. Thus, we postulate that the adhesive function of LI-cadherin is complementary to that of coexpressed classical cadherins ensuring cell-cell contacts even under conditions that downregulate the function of classical cadherins.

[Antegrade scrotal phlebography of the v. spermatica in left-sided testicular varicocele--are retrograde phlebographic classifications suitable for typing?]

PURPOSE

The study was conducted to clarify whether the use of classifications in base of retrograde phlebography would be sufficiently suitable for typifying the findings of antegrade phlebography examinations of the internal spermatic vein with regard to antegrade sclerotherapy.

SUBJECTS AND METHODS

In course of antegrade sclerotherapy in 236 patients with previously untreated idiopathic left-sided varicocele, phlebography via scrotal approach was performed. The results were compared with the relevant findings of the pre-existing classifications of the retrograde exams.

RESULTS

Comparison with the classifications of Bähren and Braedel showed distinct discrepancies. In 28.8% (Bähren) respectively 36.4% (Braedel) of our findings, typification was unsuccessful. Correspondence was found with the Riedl-classification. Collateral vessels however, are not sufficiently differentiated.

CONCLUSION

Retrograde classifications proved insufficient in typifying the findings of antegrade phlebography of the internal spermatic vein. A more subtle classification is required. This has been worked out and presented.

[Spermiogram findings following antegrade sclerosing of a varicocele]

Antegrade scrotal sclerotherapy is an established method for treatment of varicocele. Semen analysis of 103 patients at least 6 months postoperatively showed an significant increase of progressive motility from 36.5 +/- 20.7% to 51.7 +/- 20%. Evaluation of sperm density and morphology showed a significant increase too. In 79% we found an improvement of sperm density, in 63% of normal morphology and in 71% of progressive motility. There was no correlation between preoperative size of varicocele to postoperative findings in semen analysis. In 42% (n = 38) of inability to conceive the partners became pregnant. These results show that antegrade scrotal sclerotherapy is equivalent to other kinds of operative treatment for varicocele with regard to improvement of fertility parameters.

Transverse movement of spin-labeled phospholipids in the plasma membrane of a hepatocytic cell line (HepG2): implications for biliary lipid secretion

The redistribution of spin-labeled phospholipid analogs across the plasma membrane of HepG2 cells, either in suspension or grown as monolayers, was investigated. After incorporation into the outer membrane leaflet spin-labeled aminophospholipids phosphatidylserine (PS) and phosphatidylethanolamine (PE) moved rapidly to the inner monolayer, whereas the analog of phosphatidylcholine (PC) disappeared more slowly from the outer leaflet. The fast, inward movement of the aminophospholipids was abolished after adenosine triphosphate (ATP)-depletion of cells, suggesting the presence of an aminophospholipid translocase in the plasma membrane of these cells. Compared with human red blood cells, the activity of the aminophospholipid translocase is two orders of magnitude higher in HepG2 cells. From these data, a transverse phospholipid asymmetry can be inferred with the aminophospholipids mainly concentrated on the inner monolayer and the choline-containing phospholipids on the outer leaflet. The relevance of the enrichment of PC in the outer membrane leaflet for the formation and composition of the bile is discussed.

[Vascular organization of the pampiniformis plexus in the man and its significance for antegrade sclerosing of testicular varicocele]

The vascular organization of human spermatic cord was analyzed by means of injection and by casting preparation of the testicular artery and veins of the pampiniform plexus after orchiectomy. After leaving the human testis, the testicular veins are organized in two main groups and form two vein plexus. One of these vein groups forms a tight plexus around the testicular artery. Computer-aided 3-D reconstructions based on the paraffin serial sections of the human spermatic cord allowed us to demonstrate the relation between the blood vessels and the other tissue structures of the spermatic cord. The results obtained allowed us to subdivide the human spermatic cord into three compartments. The dorsomedial compartment contains the vas deferens and its blood vessels. The middle compartment contains the testicular artery and the vein group which forms a tight plexus around this artery. The ventrolateral compartment contains a vein group which shows no topographic relation to the testicular artery. This vein group is embedded in a large, macroscopically visible volume of fatty tissue. To be sure of sparing the testicular artery during antegrade sclerotherapy this vein group should be prepared.

ATP-dependent redistribution of phosphatidylethanolamine in the plasma membrane of an epithelial and a hepatocytic cell line

The redistribution of spin-labeled phospholipid analogues of sphingomyelin (SM) and phosphatidylethanolamine (PE) from the outer to the inner leaflet of the plasma membrane of an epithelial (CaCo-2) and a hepatocytic cell line (HepG2) was investigated. The amount of analogues in the outer leaflet was determined by their back-exchange to bovine serum albumin (BSA). For both cell lines a fast ATP-dependent inward movement of spinlabeled PE (SL-PE) was found while SL-SM redistributed only slowly by a passive mechanism. After depletion of intracellular ATP transverse diffusion of SL-PE was similar to that of SL-SM. The data are compatible with the presence of an aminophospholipid translocase in both cell lines.

["Contra laparoscopy" position in treatment of testicular varicocele]

Laparoscopic varicocelectomy does not offer any significant advantage in comparison to sclerotherapy or open surgical procedures. Invasiveness (transperitoneal approach, intraoperative complications, general anesthesia, duration of operation, possible ligation of the spermatic artery) is not less, but the technical expenditure and costs are higher than those in competing procedures. Laparoscopic treatment is not the procedure of first choice and even in recurrent varicocele it should only be performed if prior treatment by-repeated antegrade sclerotherapy is not successful and distal reflux has been ruled out. Therefore, the laparoscopic approach is of only minor value in the treatment of varicocele testis.

Financial analysis of antegrade scrotal sclerotherapy for men with varicoceles

OBJECTIVE

To calculate and compare the costs of the treatment of varicocele by antegrade scrotal sclerotherapy with other modalities.

PATIENTS AND METHODS

A total of 2305 operations using antegrade scrotal sclerotherapy to treat varicocele in childhood and adolescence were analysed for cost factors and compared with different surgical treatment methods for varicocele.

RESULTS

Calculation of the pre-, intra- and post-operative costs showed that antegrade scrotal sclerotherapy was the most economically effective of all forms of surgical management for varicocele.

CONCLUSIONS

Because antegrade scrotal sclerotherapy is a cost-effective treatment for varicocele, the indications for treatment may be widened to include more men with potential infertility, and thus avoid the need for expensive methods of artificial fertilization.

[Leiomyosarcoma of the spermatic cord. A case report with review of the literature]

The case of a 68-year-old man with leiomyosarcoma of the spermatic cord is reported. Radical orchiectomy with high ligature of the cord was performed. Pathological examination including immunohistochemistry demonstrated a leiomyosarcoma which seemed to arise from a spermatic cord vessel.

Direct calibration ELISA: a rapid method for the simplified determination of association constants of unlabeled biological molecules

We present a novel method for the rapid determination of association constants. The method is based on the direct calibration of an enzyme-linked immunosorbent assay (dcELISA) and does not require any external calibration. It combines kinetic and equilibrium binding experiments and can be performed on a single microtiter plate. The absorbance data are evaluated by several linearized plots without the need for sophisticated computations. The dcELISA has been used to analyze the binding of a monoclonal antibody, OKT9, to its cognate antigen, the human transferrin receptor, and yielded an association constant of Ka = 2.2 x 10(9) l/mol and a complex formation rate constant of kc = 2.7 x 10(-4) s-1. A 26% larger association constant was obtained with a radioimmunoassay (RIA)-based Scatchard analysis using 125I-labeled OKT9. By quantifying the binding of the same iodinated antibody with the dcELISA we were able to verify that the iodination modifies the binding properties of the antibody. The dcELISA thus appears to be superior to all methods requiring covalent modifications. In principle, the direct calibration method can also be combined with all other solid phase assays. It should thus expand their scope in quantifying the binding properties of biologically important molecules.

Transferrin-binding protein complex is the receptor for transferrin uptake in Trypanosoma brucei

In Trypanosoma brucei, the products of two genes, ESAG 6 and ESAG 7, located upstream of the variant surface glycoprotein gene in a polycistronic expression site form a glycosylphosphatidylinositol-anchored transferrin-binding protein (TFBP) complex. It is shown by gel filtration and membrane-binding experiments that the TFBP complex is heterodimeric and binds one molecule of transferrin with high affinity (2,300 binding sites per cell; KD = 2.1 nM for the dominant expression site from T. brucei strain 427 and KD = 131 nM for ES1.3A of the EATRO 1125 stock). The ternary transferrin-TFBP complexes with iron-loaded or iron-free ligand are stable between pH 5 and 8. Cellular transferrin uptake can be inhibited by 90% with Fab fragments from anti-TFBP antibodies. After uptake, the TFBP complex and its ligand are routed to lysosomes where transferrin is proteolytically degraded. While the degradation products are released from the cells, iron remains cell associated and the TFBP complex is probably recycled to the membrane of the flagellar pocket, the only site for exo- and endocytosis in this organism. It is concluded that the TFBP complex serves as the receptor for the uptake of transferrin in T. brucei by a mechanism distinct from that in mammalian cells.

Selective reentry of recycling cell surface glycoproteins to the biosynthetic pathway in human hepatocarcinoma HepG2 cells

Return of cell surface glycoproteins to compartments of the secretory pathway has been examined in HepG2 cells comparing return to the trans-Golgi network (TGN), the trans/medial- and cis-Golgi. Transport to these sites was studied by example of the transferrin receptor (TfR) and the serine peptidase dipeptidylpeptidase IV (DPPIV) after labeling these proteins with the N-hydroxysulfosuccinimide ester of biotin on the cell surface. This experimental design allowed to distinguish between glycoproteins that return to these biosynthetic compartments from the cell surface and newly synthesized glycoproteins that pass these compartments during biosynthesis en route to the surface. Reentry to the TGN was measured in that surface glycoproteins were desialylated with neuraminidase and were monitored for resialylation during recycling. Return to the trans-Golgi was traced measuring the transfer of [3H]fucose residues to recycling surface proteins by fucosyltransferases. To study return to the cis-Golgi, surface proteins were metabolically labeled in the presence of the mannosidase I inhibitor deoxymannojirimycin (dMM). As a result surface proteins retained N-glycans of the oligomannosidic type. Return to the site of mannosidase I in the medial/cis-Golgi was measured monitoring conversion of these glycans to those of the complex type after washout of dMM. Our data demonstrate that DPPIV does return from the cell surface not only to the TGN, but also to the trans-Golgi thus linking the endocytic to the secretory pathway. In contrast, no reentry to sites of mannosidase I could be detected indicating that the early secretory pathway is not or is only at insignificant rates accessible to recycling DPPIV. In contrast to DPPIV, TfR was very efficiently sorted from endosomes to the cell surface and did not return to the TGN or to other biosynthetic compartments in detectable amounts, indicating that individual surface proteins are subject to different sorting mechanisms or sorting efficiencies during recycling.

Functional reconstitution of the human placental transferrin receptor into phospholipid bilayers leads to long tubular structures proceeding from the vesicle surface

We have reconstituted the human placental transferrin receptor (hTfR) into phospholipid vesicles using either dialysis, dilution, or gel filtration. Several different detergents and phospholipids and a variety of lipid-to-protein weight ratios were tested. Preformed vesicles as well as detergent-solubilized phospholipids were used. Reconstituted mixtures were fractionated by sucrose density gradient centrifugation and screened for ferritransferrin binding activity, and peak fractions were analyzed by electron microscopy. The efficiency of reconstitution was strongly influenced by the choice of the phospholipids used and the reconstitution method. Best results were obtained when hTfR was dissolved with octylpolyoxyethylene, mixed with detergent-solubilized soy bean lecithin, and reconstituted by slow dialysis. The data show that hTfR capable of binding ferritransferrin was reconstituted into vesicles with an irregular surface and many protrusions. In addition the reconstitution of hTfR resulted in the formation of tubular structures proceeding from the vesicle surface, which may serve as an in vitro model for future studies on the relevance of self-assembly processes for cellular endocytosis.

Extracorporeal piezoelectric shock wave lithotripsy as mono and multiple therapy of large renal calculi including staghorn stones in unanaesthetized patients under semi-ambulant conditions

OBJECTIVE

To examine the effectiveness and complication rate of extracorporeal piezoelectric shock wave lithotripsy (EPL) as monotherapy for the treatment of large renal calculi.

PATIENTS AND METHODS

Treatment consisted of semiambulant EPL as monotherapy combined with protective ureteric stenting in 84 patients. Three groups were established according to stone volume (borderline-stone, partial and complete staghorn). An average of 18,230 shock waves was applied in 3.76 sessions to each patient.

RESULTS

No major complications were observed but there were minor complications in 33% of patients. Invasive auxiliary methods were necessary in only 12%. After a mean follow-up of 9 months (n = 72), 54% of patients were stone-free and in 22% the fragments passed spontaneously. Thus the success rate was 76%. Analysis of the three groups showed no difference in stone status during follow-up. There was no relation between the outcome of treatment and stone volume. Analysis of the patients who failed to respond to treatment showed that they were treated for longer than the stone-free group, with significantly fewer sessions per week (0.71 vs 1.28 sessions/week). It appears that higher rates of stone removal can be achieved with more frequent treatment sessions at shorter intervals.

CONCLUSION

We consider semi-ambulant EPL monotherapy to be a minimally invasive alternative treatment in patients with large renal calculi, including staghorn stones.