Epidemiology of erythema exsudativum multiforme majus, Stevens-Johnson syndrome, and toxic epidermal necrolysis in Germany (1990-1992): structure and results of a population-based registry

The severe skin reactions erythema exsudativum multiforme majus (EEM with mucosal involvement, EEMM), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN) are difficult to study as they are very rare diseases with an incidence of about two cases per 1 million inhabitants per year. We report on the structure of a registry with the aim of ascertaining all hospitalized cases of EEMM, SJS, and TEN in western Germany and Berlin. The registry is structured as an intensive reporting system, regularly contacting more than 1500 departments including 100% of the burn units (n = 34), departments of pediatrics (n = 241), departments of dermatology (n = 106), and 100% of all internal medicine departments in hospitals with intensive care facilities or with more than 200 beds (n = 1161). With a coverage rate up to 95% based on the number of responding departments between April 1, 1990 and December 31, 1992, from a total of 767 reported cases 353 patients with EEMM, SJS, and TEN were finally included in the registry. Most of these patients were directly reported to the registry; only 2.54% (9 of 353) were primarily registered by the German spontaneous reporting systems. Assuming an average population of 64.5 million for western Germany and Berlin an incidence up to 1.89 per 1 million inhabitants per year could be calculated for SJS and TEN.

Astrocytes in the hippocampus of patients with temporal lobe epilepsy display changes in potassium conductances

Functional properties of astrocytes were investigated with the patch-clamp technique in acute hippocampal brain slices obtained from surgical specimens of patients suffering from pharmaco-resistant temporal lobe epilepsy (TLE). In patients with significant neuronal cell loss, i.e. Ammon's horn sclerosis, the glial current patterns resembled properties characteristic of immature astrocytes in the murine or rat hippocampus. Depolarizing voltage steps activated delayed rectifier and transient K+ currents as well as tetrodotoxin-sensitive Na+ currents in all astrocytes analysed in the sclerotic human tissue. Hyperpolarizing voltages elicited inward rectifier currents that inactivated at membrane potentials negative to -130 mV. Comparative recordings were performed in astrocytes from patients with lesion-associated TLE that lacked significant histopathological hippocampal alterations. These cells displayed stronger inward rectification. To obtain a quantitative measure, current densities were calculated and the ratio of inward to outward K+ conductances was determined. Both values were significantly smaller in astrocytes from the sclerotic group compared with lesion-associated TLE. During normal development of rodent brain, astroglial inward rectification gradually increases. It thus appears reasonable to suggest that astrocytes in human sclerotic tissue return to an immature current pattern. Reduced astroglial inward rectification in conjunction with seizure-induced shrinkage of the extracellular space may lead to impaired spatial K+ buffering. This will result in stronger and prolonged depolarization of glial cells and neurons in response to activity-dependent K+ release, and may thus contribute to seizure generation in this particular condition of human TLE.

High rate of lymph-node metastasis in submucosal esophageal squamous-cell carcinomas and adenocarcinomas

BACKGROUND AND STUDY AIMS

The application of endoscopic mucosectomy in early esophageal cancer is limited by the presence of lymph-node metastasis. The aim of this prospective study was to analyze the rate of lymph-node involvement relative to the depth of mucosal or submucosal tumor penetration, comparing squamous-cell carcinomas and adenocarcinomas.

PATIENTS AND METHODS

A total of 60 patients with pT1 esophageal cancer--24 with squamous-cell carcinomas (SCCs) and 36 with adenocarcinomas--were treated with transthoracic en-bloc esophagectomy with two-field lymphadenectomy (n = 50) or transhiatal esophageal resection (n = 10). An average of 30 lymph nodes were examined, and the following characteristics were evaluated: histology, mucosal infiltration, depth of submucosal wall infiltration in three thirds (sm1, sm2, sm3), grading, resection category, ratio of metastatic to resected lymph nodes, and locations of metastatic nodes.

RESULTS

The rates of lymph-node metastasis were 0% for the 16 mucosal carcinomas and 45% for the 44 submucosal carcinomas (P < 0.01). There were no significant differences in the extent of lymph-node involvement between submucosal adenocarcinomas (41%) and submucosal SCCs (50%). Sm1 carcinomas were associated with a lower rate of lymph-node metastasis (SCCs 33%, adenocarcinomas 22%) than sm3 carcinomas (SCCs 69%, adenocarcinomas 78%). Two patients (9%) with submucosal SCCs and five patients (23%) with submucosal adenocarcinomas were classified as having stage pM1 lymph. The average lymph-node ratio in patients with pN1 was 0.13 for adenocarcinomas and 0.1 for SCCs (difference not significant). In the multivariate analysis, the parameters mucosal vs. submucosal (P < 0.01) and G1/G2 vs. G3 (P < 0.05) showed a significant impact in relation to metastatic lymph nodes.

CONCLUSIONS

The most important factor for predicting lymph-node metastasis in early esophageal cancer is the presence of submucosal infiltration. Early adenocarcinomas and SCCs do not differ with regard to their rate of lymphatic involvement. The rate of lymph-node metastasis increases with the depth of submucosal infiltration, but metastases can already occur in sm1 lesions. Submucosal infiltration is a contraindication for endoscopic mucosectomy. Limited surgical procedures without adequate lymphadenectomy do not appear to be appropriate in the treatment of patients with submucosal esophageal carcinomas.

A family of major royal jelly proteins of the honeybee Apis mellifera L

The characterization of major proteins of honeybee larval jelly (49-87 kDa) was performed by the sequencing of new complementary DNAs (cDNAs) obtained from a honeybee head cDNA library, by the determination of N-terminal sequences of the proteins, and by analyses of the newly obtained and known sequence data concerning the proteins. It was found that royal jelly (RJ) and worker jelly (WJ) contain identical major proteins and that all the proteins belong to one protein family designated MRJP (from Major Royal Jelly Proteins). The family consists of five main members (MRJP1, MRJP2, MRJP3, MRJP4, MRJP5). The proteins MRJP3 and MRJP5 are polymorphic. MRJPs account for 82 to 90% of total larval jelly protein, and they contain a relatively high amount of essential amino acids. These findings support the idea that MRJPs play an important role in honeybee nutrition.

Conservation genetics of the European brown bear--a study using excremental PCR of nuclear and mitochondrial sequences

In the Brenta area of northern Italy, a brown bear Ursus arctos population is rapidly going extinct. Restocking of the population is planned. In order to study the genetics of this highly vulnerable population with a minimum of stress to the animals we have developed a PCR-based method that allows the study of mitochondrial and nuclear gene sequences from droppings collected in the field. This method is generally applicable to animals in the wild. Using excremental as well as hair samples, we show that the Brenta population is monomorphic for one mitochondrial lineage and that female as well as male bears exist in the area. In addition, 70 samples from other parts of Europe were studied. As others have previously reported, the mitochondrial gene pool of European bears is divided into two major clades, one with a western and the other with an eastern distribution. Whereas populations generally belong to either one or the other mitochondrial clade, the Romanian population contains both clades. The bears in the Brenta belong to the western clade. The implications for the management of brown bears in the Brenta and elsewhere in Europe are discussed.

Analysis of plasma protein adsorption on polymeric nanoparticles with different surface characteristics

Plasma protein adsorption patterns on colloidal drug carriers acquired after i.v. administration depend on their surface characteristics and are regarded as key factors for their in vivo organ distribution. Polymeric latex particles with strongly differing surface properties were synthesized as models for colloidal drug carriers for tissue-specific drug targeting via the intravenous route. Physicochemical characterization was performed for size, surface charge density, zeta potential, and surface hydrophobicity. The interactions with human plasma proteins were studied by way of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Considerable differences in protein adsorption on the latex particles were detected with regard to the total amount of surface-bound protein on the various particle types as well as specific proteins adsorbed, for example, fibrinogen, albumin, and a recently identified plasma glycoprotein. Possible correlations between protein adsorption patterns and the physicochemical characteristics and topography of the polymeric surfaces are shown and discussed. Knowledge about protein-nanoparticle interactions can be utilized for the rational design of colloidal drug carriers and also may be useful for optimizing implants and medical devices.

Mosses as biomonitors of atmospheric heavy metal deposition: spatial patterns and temporal trends in Europe

In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found.

Late onset and increasing expression of the gap junction protein connexin30 in adult murine brain and long-term cultured astrocytes

In rat brain, expression of the gap junction protein connexin30 increased during the first 3 weeks after birth and reached its maximum after 4 weeks, as shown by analysis with specific connexin30 antibodies. This contrasts with the prenatal onset of connexin43 expression. On cryosections of rat brain, connexin30 immunoreactivity was found near blood vessels and in ependymal as well as in leptomeningeal cells. Expression in the neuropil was first noticed 3 weeks after birth, showing the same spatial pattern of immunoreactivity as connexin43. This late onset of connexin30 expression in astrocytes was also seen in long-term glial cell cultures, where connexin30 was coexpressed with the astrocytic marker proteins S-100beta and glial fibrillary acid protein. In acute brain slices, connexin30 immunofluorescent signals were detected on processes of functionally identified astrocytes. Thus, our results show that connexin30 is expressed in three different cell types of the rodent brain. The late onset of connexin30 expression in astrocytes suggests that this gap junctional protein fulfills a role in intercellular communication among mature astrocytes.

2-[Fluorine-18]-fluoro-2-deoxy-d-glucose positron emission tomography in the diagnosis of recurrent ovarian cancer

OBJECTIVE

The aim of the study was to investigate the role of 2-[fluorine-18]-fluoro-2-deoxy-d-glucose positron emission tomography (FDG PET) in the diagnosis of recurrent ovarian cancer.

METHODS

One hundred six FDG PET scans performed in 54 patients in the follow-up after cytoreductive surgery and chemotherapy of ovarian cancer were reevaluated. Fifty-eight scans were performed in patients with suspected recurrence and 48 scans in patients who were clinically disease free. Thirty-seven PET scans were validated by histology and 66 studies by a median follow-up of 22 months in disease-free patients or 12 months in patients with recurrent disease. Three scans were validated by concordant positive findings of tumor marker CA125, computed tomography, and FDG PET.

RESULTS

FDG PET correctly identified recurrent disease in 73/88 cases. PET ruled out recurrent disease in 15/18 cases. The sensitivity and specificity for PET were 83 and 83%, respectively. In patients with suspected disease, sensitivity was 94% compared to 65% in patients judged clinically disease free. The sensitivity of PET was 96% if suspicion of recurrence was based on a rise of CA125 alone. PET preceded the conventional diagnosis by a median of 6 months in patients judged clinically free of disease. The median relapse-free interval after a negative PET scan was 20 months.

CONCLUSION

FDG PET provides the chance to detect recurrent ovarian cancer at an earlier stage during follow-up. Patients with a negative PET scan have a longer relapse-free interval than patients with a positive PET scan.

Functional and molecular properties of human astrocytes in acute hippocampal slices obtained from patients with temporal lobe epilepsy

PURPOSE

The specific role of glial cells in epilepsy is still elusive. In this study, functional properties of astrocytes were investigated in acute hippocampal brain slices obtained from surgical specimens of patients with drug-resistant temporal lobe epilepsy (TLE).

METHODS

The patch-clamp technique together with a single-cell reverse transcription-polymerase chain reaction approach were used to combine functional and molecular analysis in the same individual cell in situ.

RESULTS

In patients with Ammon's horn sclerosis, the glial current patterns resembled properties of immature astrocytes in rodent hippocampus. Depolarizing voltage steps activated delayed rectifier and transient K+ currents as well as tetrodotoxin-sensitive Na+ currents. Hyperpolarizing voltages elicited inward rectifier K+ currents. Comparative recordings were made in astrocytes from patients with lesion-associated TLE that lacked significant histopathological hippocampal alterations. The inward rectifier K+ current density was significantly smaller in astrocytes from the sclerotic group compared with lesion-associated TLE patients.

CONCLUSIONS

During normal development of rodent brain, astroglial inward rectification gradually increases. It thus appears that astrocytes in human sclerotic tissue reexpress an immature current pattern. Reduced astroglial inward rectification in conjunction with seizure-induced shrinkage of the extracellular space may lead to impaired spatial K+ buffering. This will result in stronger and prolonged depolarization of glial cells and neurons in response to activity-dependent K+ release and may thus contribute to seizure generation and spread in this particular condition of human TLE.

The primary structure of bovine brain myelin lipophilin (proteolipid apoprotein)

The amino-acid sequence of bovine myelin lipophilin (proteolipid apoprotein, Folch-protein) has been completed. Lipophilin is a 276 amino acid residues containing, extremely hydrophobic membrane protein with molecular mass 30,000 Da. The sequence determination was based on automated Edman degradation of four tryptophan and four cyanogen bromide fragments and of proteolytic peptides of complete lipophilin as well as the fragments obtained by chemical cleavage. Four additional sequences were determined which led to the completion of the primary structure. Lipophilin is esterified at threonine-198 by long chain fatty acids (palmitic, stearic and oleic acid). The attachment site has been established at the same threonine residue in three different peptides isolated from thermolysinolytic, papainolytic and chymotrypsinolytic hydrolysates. This threonine residue is part of a hydrophilic segment of lipophilin. The covalent fatty acyl bond is being discussed together with important structural and functional properties of this membrane protein which can be derived from sequence information. New separation and purification methods of hydrophobic and hydrophilic polypeptides for this sequence determination (fractional solubilization, silica gel exclusion, high-performance liquid chromatography) had to be elaborated as indispensable tools. They are generally applicable to the structural analysis of hydrophobic membrane proteins. Four long (26, 29, 40 and 36 residues) and one medium long (12 residues) hydrophobic segments are separated by four predominantly positively and one negatively charged hydrophilic segments. On the basis of structural data a model for the membrane integration of lipophilin is proposed.

SseBCD proteins are secreted by the type III secretion system of Salmonella pathogenicity island 2 and function as a translocon

The type III secretion system encoded by Salmonella pathogenicity island 2 (SPI2) is required for systemic infections and intracellular accumulation of Salmonella enterica. This system is induced by intracellular Salmonella and subsequently transfers effector proteins into the host cell. Growth conditions either inducing expression of the type III secretion system or the secretion of substrate proteins were defined. Here we report the identification of a set of substrate proteins consisting of SseB, SseC, and SseD that are secreted by the SPI2 system in vitro. Secretion was observed if bacterial cells were exposed to acidic pH after growth in minimal medium with limitation of Mg(2+) or phosphate. SseB, -C, and -D were isolated in a fraction detached from the bacterial cell surface by mechanical shearing, indicating that these proteins are predominantly assembled into complexes on the bacterial cell surface. The three proteins were required for the translocation of SPI2 effector proteins SspH1 and SspH2 into infected host cells. Thus, SseB, SseC, and SseD function as the translocon for effector proteins by intracellular Salmonella.

Lymph node size and metastatic infiltration in colon cancer

BACKGROUND

Detection of metastatic lymph nodes in colon cancer is essential for determining stage and adjuvant treatment modalities. Lymph node size has been used as one possible criterion for nodal metastasis. Although enlarged regional lymph nodes are generally interpreted as metastases, few data are available that correlate lymph node size with metastatic infiltration in colon cancer.

METHODS

In a prospective morphometric study, the regional lymph nodes from 30 colon specimens from consecutive patients with primary colon cancer were analyzed. The lymph nodes were counted and the largest diameter of each lymph node was measured and analyzed for metastatic involvement by histological examination.

RESULTS

A total of 698 lymph nodes were present in the 30 specimens examined for this study. A mean number of 23 (range, 19-39) lymph nodes was found in each specimen. Of these nodes, 566 (81%) were tumor-free and 132 (19%) contained metastases. The mean diameter of the lymph nodes free of metastases was 3.9 mm, whereas those infiltrated by metastases averaged 5.9 mm in diameter (P < 0.0001). Of the tumor-free lymph nodes, 528 (93%) measured < 5 mm in diameter, whereas 70 (53%) lymph nodes containing metastases measured < 5 mm in diameter.

CONCLUSIONS

Lymph node size is not a reliable indicator for lymph node metastasis in colon cancer. A careful histological search for small lymph node metastasis in the specimen should be undertaken to avoid false-negative node staging.

The distribution of macrophages in spiral arteries of the placental bed in pre-eclampsia differs from that in healthy patients

Placental bed biopsies taken during caesarean section from 10 patients with pre-eclampsia and six healthy pregnancies were studied. We applied antibodies against cytokeratin and different macrophage markers to analyse the distribution of invasive extravillous trophoblast cells as compared to that of macrophages in myometrial segments of uteroplacental arteries. The data were evaluated quantitatively. We found a clear inverse relationship between local infiltration with macrophages and trophoblast invasion. In pre-eclampsia, vessel cross-sections prevailed which were characterized by large numbers of macrophages but a low degree of trophoblast invasion. In contrast, in normal third trimester pregnancies the respective arterial segments had a high degree of trophoblast invasion but were largely void of macrophages. These data suggest causal links between macrophages and inhibition of intra-arterial trophoblast invasion in pre-eclampsia.

Options in the management of esophageal perforation: analysis over a 12-year period

Controversies exist about the management of esophageal perforation in order to eliminate the septic focus. The aim of this study was to assess the etiology, management, and outcome of esophageal perforation over a 12-year period, in order to characterize optimal treatment options in this severe disease. Between May 1996 and May 2008, 44 patients (30 men, 14 women; median age 67 years) with esophageal perforation were treated in our department. Etiology, diagnostic procedures, time interval between clinical presentation and treatment, therapeutic management, and outcome were analyzed retro- or prospectively for each patient. Iatrogenic injury was the most frequent cause of esophageal perforation (n= 28), followed by spontaneous (n= 9) and traumatic (n= 4) esophageal rupture (in three patients, the reasons were not determinable). Eight patients (18%) underwent conservative treatment with cessation of oral intake, antibiotics, and parenteral nutrition. Twelve (27%) patients received an endoscopic stent implantation. Surgical therapy was performed in 24 (55%) patients with suturing of the lesion in nine patients, esophagectomy with delayed reconstruction in 14 patients, and resection of the distal esophagus and gastrectomy in one patient. In case of iatrogenic perforation, conservative or interventional therapy was performed each in 50% of the patients; 89% of the patients with a Boerhaave syndrome underwent surgery. The hospital mortality rate was 6.8% (3 of 44 patients): one patient with an iatrogenic perforation after conservative treatment, and two patients after surgery (one with Boerhaave syndrome, one with iatrogenic rupture). No death occurred in the 25 patients with a diagnostic interval less than 24 hours, whereas the mortality rate in the group (n= 16 patients) with a diagnostic interval of more than 24 hours was 19% (P= 0.053). In three patients, the diagnostic interval was not determinable retrospectively. An individualized therapy depending on etiology, diagnostic delay, and septic status leads to a low mortality of esophageal perforation.

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.

Functional plasticity of the N/OFQ-NOP receptor system determines analgesic properties of NOP receptor agonists

Despite high sequence similarity between NOP (nociceptin/orphanin FQ opioid peptide) and opioid receptors, marked differences in endogenous ligand selectivity, signal transduction, phosphorylation, desensitization, internalization and trafficking have been identified; underscoring the evolutionary difference between NOP and opioid receptors. Activation of NOP receptors affects nociceptive transmission in a site-specific manner, with antinociceptive effects prevailing after peripheral and spinal activation, and pronociceptive effects after supraspinal activation in rodents. The net effect of systemically administered NOP receptor agonists on nociception is proposed to depend on the relative contribution of peripheral, spinal and supraspinal activation, and this may depend on experimental conditions. Functional expression and regulation of NOP receptors at peripheral and central sites of the nociceptive pathway exhibits a high degree of plasticity under conditions of neuropathic and inflammatory pain. In rodents, systemically administered NOP receptor agonists exerted antihypersensitive effects in models of neuropathic and inflammatory pain. However, they were largely ineffective in acute pain while concomitantly evoking severe motor side effects. In contrast, systemic administration of NOP receptor agonists to non-human primates (NHPs) exerted potent and efficacious antinociception in the absence of motor and sedative side effects. The reason for this species difference with respect to antinociceptive efficacy and tolerability is not clear. Moreover, co-activation of NOP and μ-opioid peptide (MOP) receptors synergistically produced antinociception in NHPs. Hence, both selective NOP receptor as well as NOP/MOP receptor agonists may hold potential for clinical use as analgesics effective in conditions of acute and chronic pain.

Influence of sequence-dependent cytosine protonation and methylation on DNA triplex stability

To investigate cytosine protonation and its influence on the sequence-dependent thermal stability of DNA triplexes in detail, we have employed homo- and heteronuclear NMR experiments on specifically (15)N-labeled oligodeoxynucleotides that were designed to fold into intramolecular triple helices of the pyrimidine motif under appropriate conditions. These experiments reveal that cytosines in central positions of the triplex are significantly protonated even at neutral pH. However, semiprotonation points for individual cytosine bases as determined from pH-dependent measurements show considerable differences depending on their position. Thus, protonation is disfavored for adjacent cytosines or for cytosines at the triplex termini, resulting in a smaller contribution to the overall free energy of the triple helical system. In contrast, protonation of the base upon substitution of 5-methylcytosine for cytosine in the triplex third strand is only affected to a minor extent, and triplex stabilization by the methyl substituent is shown to primarily arise from stacking energies and/or hydrophobic effects.

Relaxase (TraI) of IncP alpha plasmid RP4 catalyzes a site-specific cleaving-joining reaction of single-stranded DNA

Conjugative DNA transfer of the self-transmissible broad-host-range plasmid RP4 is initiated by strand- and site-specific cleavage at the nick site (nic) of the transfer origin (oriT). Cleavage results in covalent attachment of the plasmid-encoded relaxase (TraI) to the 5'-terminal 2'-deoxycytidine residue at nic. We demonstrate that Tyr22 is the center of the catalytic site of TraI, mediating cleavage via formation of a phosphodiester between the DNA 5' phosphoryl and the aromatic hydroxyl group. The specificity of cleavage seen with form I oriT DNA was verified with short oligodeoxy-ribonucleotides embracing the nick region. The reaction requires TraI and Mg2+ but is independent of the relaxosome component TraJ. Cleavage produces one oligonucleotide fragment with a free 3' hydroxyl, the other part forms a covalent TraI-oligonucleotide adduct. Like nicking of form I oriT DNA, TraI-catalyzed oligonucleotide cleavage reaches an equilibrium when about 30% of the input TraI exists as a covalent protein-DNA complex. In the presence of two differently sized oligonucleotides, defined hybrid oligonucleotides are produced, demonstrating that TraI catalyzes recombination of two single strands at nic. This finding shows that TraI possesses cleaving-joining activity resembling that of a type I topoisomerase. Reactions are dependent on the sequence of the 3'-terminal 6 nucleotides adjacent to nic. Only certain base changes in a few positions are tolerated, whereas the sequence of the 5' terminal nucleotides apparently is irrelevant for recognition by TraI. The reactions described here further support the hypothesis that DNA transfer via conjugation involves a rolling circle-like mechanism which generates the immigrant single strand while DNA-bound TraI protein scans for the occurrence of a second cleavage site at the donor-recipient interface.

Splenectomy in proximal gastric cancer: frequency of lymph node metastasis to the splenic hilus

BACKGROUND AND OBJECTIVES

The indication for splenectomy in proximal gastric cancer remains controversial. Splenectomy is performed because of possible lymph node metastasis of the splenic hilus or infiltration/metastasis of the spleen. The purpose of this study was to investigate the frequency of lymph node metastasis to the splenic hilus and metastasis to the spleen in proximal gastric carcinomas.

METHODS

In a morphologic study, the frequency of lymph node metastasis to the splenic hilus in 112 patients with proximal gastric cancer was investigated with particular emphasis on its correlation with established clinicopathological characteristics and classifications. Seventy-seven gastrectomy specimens were obtained from men and 35 from women. Patients ranged in age from 20 to 89 years (median 60 years). All patients underwent a potential curative resection (RO resection) with total gastrectomy and pancreas-preserving splenectomy. None of the patients had been treated preoperatively with cytotoxic drugs or radiation.

RESULTS

A mean number of three lymph nodes (range 0-8) in the splenic hilus was found in each specimen. The incidence of lymph node metastasis of the splenic hilus was 9.8% (n=11). Lymph node metastasis was only observed in advanced proximal gastric cancer (UICC IIIb/IV) located at the greater curvature and in Borrmann type III/IV cancer with advanced lymph node metastasis. An infiltration of the spleen was seen only in two cases with advanced stages of gastric carcinoma (stage IV).

CONCLUSIONS

Based on our data lymph node metastasis to the splenic hilus is rarely observed in proximal gastric cancer and only found in advanced cancer (UICC IIIb/IV) especially in tumors of the greater curvature and of Borrmann type IV cancer.

Synergistic interaction between the two mechanisms of action of tapentadol in analgesia

The novel centrally acting analgesic tapentadol [(-)-(1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol hydrochloride] combines two mechanisms of action, μ-opioid receptor (MOR) agonism and noradrenaline reuptake inhibition (NRI), in a single molecule. Pharmacological antagonism studies have demonstrated that both mechanisms of action contribute to the analgesic effects of tapentadol. This study was designed to investigate the nature of the interaction of the two mechanisms. Dose-response curves were generated in rats for tapentadol alone or in combination with the opioid antagonist naloxone or the α(2)-adrenoceptor antagonist yohimbine. Two different pain models were used: 1) low-intensity tail-flick and 2) spinal nerve ligation. In each model, we obtained dose-effect relations to reveal the effect of tapentadol based on MOR agonism, NRI, and unblocked tapentadol. Receptor fractional occupation was determined from tapentadol's brain concentration and its dissociation constant for each binding site. Tapentadol produced dose-dependent analgesic effects in both pain models, and its dose-effect curves were shifted to the right by both antagonists, thereby providing data to distinguish between MOR agonism and NRI. Both isobolographic analysis of occupation-effect data and a theoretically equivalent methodology determining interactions from the effect scale demonstrated very pronounced synergistic interaction between the two mechanisms of action of tapentadol. This may explain why tapentadol is only 2- to 3-fold less potent than morphine across a variety of preclinical pain models despite its 50-fold lower affinity for the MOR. This is probably the first demonstration of a synergistic interaction between the occupied receptors for a single compound with two mechanisms of action.

The role of plasma proteins in brain targeting: species dependent protein adsorption patterns on brain-specific lipid drug conjugate (LDC) nanoparticles

The in vivo organ distribution of particulate drug carriers is decisively influenced by the interaction with plasma proteins after i.v. administration. Serum protein adsorption on lipid drug conjugate nanoparticles, a new carrier system for i.v. application, was investigated by 2-dimensional electrophoresis (2-DE). The particles were surface-modified to target them to the brain. To assess the protein adsorption pattern after i.v. injection in mice prior to in vivo studies, the particles were incubated in mouse serum. Incubation in human serum was carried out in parallel to investigate similarities or differences in the protein patterns obtained from men and mice. Distinct differences were found. Particles incubated in human serum showed preferential adsorption of apolipoproteins A-I, A-IV and E. Previously, preferential adsorption of ApoE was reported as one important factor for targeting of Tween(R)80 modified polybutylcyanoacrylate nanoparticles to the brain. Preferential adsorption of ApoA-I and A-IV took place after incubation in mouse serum, adsorption of ApoE could not be clearly confirmed. In vivo localization of the LDC nanoparticles at the blood-brain barrier and diffusion of the marker Nile Red into the brain could be shown by confocal laser-scanning microscopy. Differences of the obtained adsorption patterns are discussed with regard to their relevance for correlations of in vitro and in vivo data obtained from different species.

Staging of gastric cancer: correlation of lymph node size and metastatic infiltration

OBJECTIVE

The assessment of lymphatic metastases is an important factor in the staging of gastric cancer. Lymph node size has been used as one criterion for possible nodal metastasis. Although enlarged regional lymph nodes are generally interpreted as metastases, few data are available that correlate lymph node size with metastatic infiltration.

MATERIALS AND METHODS

In a prospective morphometric study, the regional lymph nodes from 31 gastrectomy specimens of consecutive patients with primary gastric adenocarcinoma were analyzed. The lymph nodes were counted, the largest diameter of each node was measured, and each node was analyzed for metastatic involvement by histologic examination. The frequency of metastatic involvement was calculated and correlated to lymph node size.

RESULTS

A total of 1253 lymph nodes were present in the 31 specimens examined for this study. A mean number of 40 lymph nodes (range, 20-53) were found in each specimen. Of these 1253 nodes, 922 (74%) were tumor-free and 331 (26%) contained metastases. The mean diameter of the lymph nodes free of metastases was 4.1 mm, whereas that of nodes infiltrated by metastases was 6.0 mm (p < .0001). Of the tumor-free lymph nodes, 735 (80%) were less than 5 mm in diameter, whereas 182 (55%) nodes containing metastases were less than 5 mm in diameter. Of the 10 patients without lymph node metastases, seven had at least one node that was 10 mm or greater in diameter; similarly, 15 (71%) of the 21 patients with node metastases had at least one node that was 10 mm or greater in diameter.

CONCLUSION

Lymph node size is not a reliable indicator for lymph node metastasis in patients with gastric cancer.