From maternal glucose to fetal glycogen: expression of key regulators in the human placenta

The present study investigated the expression of glycogenin, the protein primer for glycogen synthesis, and the high affinity glucose transporter isoform GLUT3 as a further potential regulator of cellular glycogen metabolism, in first trimester and term human placenta using immunohistochemistry and Western blotting. At term, glycogenin was most abundant in the endothelium of fetal vessels. Trophoblast as well as basal decidual cells were moderately stained. The glycogenin distribution pattern in first trimester placentae resembled that at term, but reactivity was generally less intense. Extravillous trophoblast and villous cytotrophoblast were the major sites of GLUT3 expression. Endothelial cells were also strongly labelled with the GLUT3 antiserum. Western blotting identified both free and glucosylated glycogenin, as well as a 48 kDa band reacting with GLUT3 antiserum in placental villous tissue. Glycogenin immunoreactivity remained unaffected by amylolytic glycogen digestion, although preceding electron microscopical examination demonstrated the presence of glycogen. These data may indicate that placental glycogenin can be recycled from the immature glycogen or that it is located on the surface of the glycogen molecule. In conclusion, the co-expression of glycogenin with GLUT3 might enable glycogen-storing cells to exchange glucose quite effectively according to prevailing metabolic demands of glycogen synthesis or degradation.

Impairment of the plasmin activation system in primary pulmonary hypertension: evidence for gender differences

Primary pulmonary hypertension (PPH) is a rare disorder, with marked in-situ thrombosis of small pulmonary vessels occurring primarily in adult women. We investigated whether differences in the plasmin- and thrombin activation system are associated with the predominate affection of females. Plasma levels of plasminogen activator inhibitor type 1 (PAI-1), tissue-type plasminogen activator (t-PA), fibrinogen, thrombin-antithrombin (TAT) complexes, and prothrombin fragments (F1.2) were measured at baseline and after standardized venous occlusion (VO) in patients with PPH (24 female, 9 male). At baseline, females showed significant higher TAT levels (p = 0.05), higher t-PA antigen levels (p = 0.01) and higher fibrinogen levels (p = 0.03) with positive correlation to mean pulmonary artery pressure (mPAP), as well as nonsignificant lower t-PA activity, higher PAI-1 antigen and activity and F1.2 levels. After VO, females showed a significantly blunted increase in t-PA antigen (p = 0.01) and t-PA activity (p = 0.001), correlating with mPAP, as well as increased PAI-1 activity (p = 0.05). We hypothesize, that the observed presence of gender differences in the plasmin- and thrombin activation system in PPH leading to an antifibrinolytic/prothrombotic state might, in part, explain the female predominant incidence of this disease.

Self-expanding metal esophageal stent with anti-reflux mechanism

BACKGROUND

When deployed across the gastroesophageal junction, self-expanding metal esophageal stents can predispose to gastroesophageal reflux. Our aim was to evaluate the efficacy of a self-expanding metal esophageal stent that was modified to prevent gastroesophageal reflux.

METHODS

The polyurethane coating of a metal Z-stent was extended beyond its lower end to form windsock-type valve. The anti-reflux property of this stent was studied in vitro by submerging the stent under water and measuring the pressure required to invert the valve. Esophageal acid exposure time was measured in 5 dogs with a standard and the modified stent placed across the gastroesophageal junction. The modified stent was also placed in 11 patients with cancer of the gastroesophageal junction who were prospectively followed.

RESULTS

The pressure required to invert the valve was directly proportional to the thickness of the valve membrane (48 +/- 0.4 cm water for a 0.0067-inch thick membrane). Esophageal acid exposure time was significantly less with the modified stent as compared with a standard stent (1% +/- 0.3%, 49% +/- 11%, respectively, p = 0.03). Dysphagia score in patients improved from 3.4 +/- 0.1 to 1.1 +/- 0.2 (p < 0.001). Daytime heartburn and regurgitation scores were less than 1 (score 10 = severe). No patient complained of nocturnal reflux symptoms. Karnofsky performance status scale did not improve significantly.

CONCLUSIONS

The efficacy of the modified stent in relieving dysphagia is comparable with a standard stent. It also effectively prevents gastroesophageal reflux.

Identification of a novel exon in apolipoprotein E receptor 2 leading to alternatively spliced mRNAs found in cells of the vascular wall but not in neuronal tissue

Novel members of the low density lipoprotein receptor family were identified in human endothelial and vascular smooth muscle cells utilizing a homology-cloning strategy. Four novel mRNA transcripts could be identified as isoforms of the apolipoprotein E receptor 2 (apoEr2): one form lacking three ligand binding repeats (nucleotides 497-883) but containing a novel ligand binding repeat adjacent to a unique cysteine-rich domain preceding the epidermal growth factor precursor domain of apoEr2, forms lacking the O-linked sugar domain, and forms containing a 59-amino acid deletion within the cytoplasmic tail. By fluorescence in situ hybridization for chromosome mapping, we could confirm that the novel alternative forms of apoEr2 are splice variants of transcripts from a single copy gene on chromosome 1p34. To analyze whether the different splice variants of apoEr2 mRNA are expressed in a splice variant-specific pattern, we concentrated on the central nervous system, where high expression of apoEr2 has been described originally. By means of splice variant-specific in situ hybridization, we could confirm that apoEr2 mRNA is abundantly expressed in brain tissue and, with exception of the newly identified ligand binding domain, all mRNA splice variants exhibited a similar expression pattern. The mRNA of the newly identified ligand binding domain, however, was expressed in brain only in cells of the vascular wall, confirming data from Northern blotting, where the mRNA of the newly identified ligand binding domain was found in several tissues but was absent in brain tissue.

[Identification of high risk patients with severe, but asymptomatic aortic stenosis]

Whether asymptomatic patients with severe aortic stenosis benefit from surgery remains unclear. We report our data recently published in the New England Journal of Medicine on the natural history of this disease and predictors of outcome.

Dopamine-induced epithelial K(+) and Na(+) movements in the salivary ducts of Periplaneta americana

K(+)- and Na(+)-selective double-barrelled microelectrodes were used for intracellular and luminal measurements in salivary ducts of Periplaneta americana. The salivary ducts were stimulated with dopamine (10(-6) mol l(-1)). Dopamine decreased intracellular [K(+)] from 112+/-17 mmol l(-1) to 40+/-13 mmol l(-1) (n=6) and increased intracellular [Na(+)] from 22+/-19 mmol l(-1) to 92+/-4 mmol l(-1) (n=6). Luminal [K(+)] was 15+/-3 mmol l(-1) in the unstimulated salivary ducts and increased to 26+/-11 mmol l(-1) upon stimulation with dopamine (n=10). Luminal [Na(+)] was insignificantly increased from 105+/-25 mmol l(-1) to 116+/-22 mmol l(-1) (n=12) by stimulation with dopamine. The potential difference across the basolateral membrane (PD(b)) was depolarized from -65+/-6 mV to -31+/-13 mV (n=12) and the transepithelial potential difference (PD(t)) was hyperpolarized from -13+/-6 mV to -22+/-7 mV (n=22, lumen negative) upon stimulation with dopamine. The re-establishment of prestimulus values of intracellular [K(+)] and [Na(+)] and PD(b) was inhibited by basolateral addition of ouabain (10(-4) mol l(-1)). Furosemide (10(-4) mol l(-1)) in the bath inhibited the dopamine-induced increase in intracellular [Na(+)], the decrease in intracellular [K(+)] and the depolarization of PD(b). We propose a model for dopamine-stimulated ion transport in the salivary ducts involving basolateral Na(+)-K(+)-2Cl(-) cotransport and active extrusion of K(+) via the apical membrane.

[Experiences with the German Endoprosthesis Register]

The German Endoprostheses Register started its documentation of primary and revision surgery on major joints in 1997. About 7000 primary arthroplasties and 1100 revisions on hip joints as well as 3000 primary arthroplasties and 250 revisions on knee joints are registered annually by 41 hospitals, which amounts to 60% in primary or 80% in revision surgery of the Swedish arthroplasty register. 95% of the revisions are performed on implants which have not been primarily operated on by the hospitals enrolled to the register, normally recruiting the classical "lost-to-follow-up-cases". Especially the removed implants show a conspicuous diversity of models. More than 10 specimens were removed in only 24 of 173 different types of hip-stems and 21 of 133 different types of hip-sockets. Thus, in order to cover not only a small number of types of implants by statistical analysis, large numbers of surgery have to be registered to yield case-numbers which can not be achieved by registers of small countries like the Scandinavian. Germany with approximately 1900 relevant clinical departments owns a slumbering potential that could easily be recruited.

Aerosolized iloprost therapy could not replace long-term IV epoprostenol (prostacyclin) administration in severe pulmonary hypertension

OBJECTIVES

To switch patients with severe pulmonary hypertension and previous life-threatening catheter-related complications from long-term IV epoprostenol therapy to aerosolized iloprost therapy.

DESIGN

Open, uncontrolled trial.

SETTING

Medical ICU of a university hospital.

PATIENTS

Two patients with primary pulmonary hypertension and one patient with pulmonary hypertension after surgical closure of atrial septal defect (mean pulmonary artery pressure > or =50 mm Hg). All were classified as New York Heart Association class II under treatment with continuous IV epoprostenol for 4 years.

INTERVENTIONS

Stepwise reduction of IV epoprostenol (1 ng/kg/min steps every 3 to 10 h) during repeated inhalations of aerosolized iloprost (150 to 300 microg/d with 6 to 18 inhalations/d). Continuous pulmonary and systemic arterial monitoring were performed.

RESULTS

Aerosolized iloprost reduced pulmonary artery pressure by 49%, 49%, and 45%, respectively, and increased cardiac output by 70%, 75%, and 41% in the three patients. The effect lasted for 20 min and was similar at different doses of IV epoprostenol. Persistent treatment change to inhaled iloprost could not be achieved because all patients developed signs of right heart failure. After termination of iloprost inhalations, return to standard epoprostenol therapy led to clinical and hemodynamic restoration.

CONCLUSIONS

Although aerosolized iloprost demonstrated short-term hemodynamic effects, it could not be utilized as alternative chronic vasodilator in patients with severe pulmonary hypertension.

Predictors of outcome in severe, asymptomatic aortic stenosis

BACKGROUND

Whether to perform valve replacement in patients with asymptomatic but severe aortic stenosis is controversial. Therefore, we studied the natural history of this condition to identify predictors of outcome.

METHODS

During 1994, we identified 128 consecutive patients with asymptomatic, severe aortic stenosis (59 women and 69 men; mean [+/-SD] age, 60+/-18 years; aortic-jet velocity, 5.0+/-0.6 m per second). The patients were prospectively followed until 1998.

RESULTS

Follow-up information was available for 126 patients (98 percent) for a mean of 22+/-18 months. Event-free survival, with the end point defined as death (8 patients) or valve replacement necessitated by the development of symptoms (59 patients), was 67+/-5 percent at one year, 56+/-5 percent at two years, and 33+/-5 percent at four years. Five of the six deaths from cardiac disease were preceded by symptoms. According to multivariate analysis, only the extent of aortic-valve calcification was an independent predictor of outcome, whereas age, sex, and the presence or absence of coronary artery disease, hypertension, diabetes, and hypercholesterolemia were not. Event-free survival for patients with no or mild valvular calcification was 92+/-5 percent at one year, 84+/-8 percent at two years, and 75+/-9 percent at four years, as compared with 60+/-6 percent, 47+/-6 percent, and 20+/-5 percent, respectively, for those with moderate or severe calcification. The rate of progression of stenosis, as reflected by the aortic-jet velocity, was significantly higher in patients who had cardiac events (0.45+/-0.38 m per second per year) than those who did not have cardiac events (0.14+/-0.18 m per second per year, P<0.001), and the rate of progression of stenosis provided useful prognostic information. Of the patients with moderately or severely calcified aortic valves whose aortic-jet velocity increased by 0.3 m per second or more within one year, 79 percent underwent surgery or died within two years of the observed increase.

CONCLUSIONS

In asymptomatic patients with aortic stenosis, it appears to be relatively safe to delay surgery until symptoms develop. However, outcomes vary widely. The presence of moderate or severe valvular calcification, together with a rapid increase in aortic-jet velocity, identifies patients with a very poor prognosis. These patients should be considered for early valve replacement rather than have surgery delayed until symptoms develop.

Wood dust exposure and cancer incidence: a retrospective cohort study of furniture workers in Estonia

BACKGROUND

Occupational wood dust exposure is associated with increased risk of sinonasal cancer in men. However, little is known whether it is associated with sinonasal cancer in women or with malignancies of other sites.

METHODS

In a retrospective cohort study of furniture workers, cancer incidence in 3723 men and 3063 women between 1968 and 1995 was compared to the incidence in the general population of Estonia. Cancer risks were analyzed by employment duration and occupation.

RESULTS

The standardized incidence ratio (SIR) for all cancers did not differ significantly from one. Two men and one woman had sinonasal cancer (expected 1.07 and 0.53, respectively). Significantly increased risk of colon cancer was seen in the cohort (SIR 1.65, 95% confidence interval (CI) 1.22-2.17). Subjects employed for 10 years and over had significant excess of colon cancer (SIR 2.29, 95% CI 1.28-3.77) and rectal cancer (SIR 2.10, 95% CI 1.05-3.76) in the analysis by employment duration using exposure with a latency of 20 years. The nonsignificant excess of pharyngeal cancer in men (SIR 1.82) and lung cancer in women (SIR 1.43) was restricted to short-term workers.

CONCLUSIONS

This study found an excess of colon and rectal cancer in furniture workers. There was no increase in total cancer risk.

Pulmonary artery thromboendarterectomy: a comparison of two different postoperative treatment strategies

Pulmonary artery thromboendarterectomy (PTE) is a potentially curative surgical procedure for chronic thromboembolic pulmonary hypertension. It is, nevertheless, associated with considerable mortality caused by postoperative complications, such as reperfusion pulmonary edema (RPE) (i.e., pulmonary infiltrates in regions distal to vessels subjected to endarterectomy) and right heart failure (RHF). However, there are no reports about the influence of different postoperative treatment strategies on complications and mortality. Therefore, we compared two different treatment strategies. In Group I (n = 33), positive inotropic catecholamines and vasodilators were avoided during termination of cardiopulmonary bypass (CPB) and thereafter, and mechanical ventilation was performed with low tidal volumes < 8 mL/kg, duration of inspiration:duration of expiration = 3:1, and peak inspiratory pressures < 18 cm H(2)O. In Group II (n = 14), positive inotropic catecholamines and vasodilators were regularly used for termination of CPB and thereafter, and ventilation was performed with high tidal volumes (10-15 mL/kg) and peak inspiratory pressures up to 50 cm H(2)O. Hemodynamics, the incidence of RPE and RHF, duration of ventilation, morbidity, and mortality were recorded. Cardiac index was comparable before surgery (2.11 +/- 0.09 vs 2.08 +/- 0.09 L. min(-1). m(-2)) and 20 min after CPB (2.26 +/- 0.09 vs 2.60 +/- 0.20 L. min(-1). m(-2)). RPE occurred in 6.1% (Group I) versus 14.3% (Group II), and RHF was observed in 9.1% (Group I) versus 21.4% (Group II). Mortality was 9.1% (Group I) versus 21.4% (Group II). Thus, the avoidance of positive inotropic catecholamines and vasodilators in combination with nonaggressive mechanical ventilation after PTE was associated with a low incidence of RPE, RHF, duration of ventilation, and mortality after PTE.

IMPLICATIONS

The avoidance of positive inotropic catecholamines and vasodilators in combination with nonaggressive mechanical ventilation was associated with a low incidence of reperfusion pulmonary edema and/or right heart failure after pulmonary artery thromboendarterectomy.

Dye-coupling between cells of the salivary glands in the cockroach Periplaneta americana

Cockroaches have acinar salivary glands. The acini consist of peripheral cells specialized for electrolyte and water transport and central cells contributing proteinaceous components to the saliva. Salivary duct cells probably modify the primary saliva. The acinar cells in Nauphoeta cinerea had been shown to be electrically coupled and dye-coupled. Since intercellular communication via gap junctions between acinar cells is difficult to reconcile with previous findings that dopamine and serotonin selectively stimulate the secretion of either protein-free or protein-rich saliva in Periplaneta americana, we investigated whether dye-coupling occurs between both acinar cell types and between duct cells. We iontophoretically loaded Lucifer yellow into impaled cells and tested for dye-coupling by confocal laser scanning microscopy. We found that: (1) peripheral and central cells within an acinar lobulus of the gland in P. americana are dye-coupled; and (2) salivary duct cells are dye-coupled.

Mg(2+) transport in sheep rumen epithelium: evidence for an electrodiffusive uptake mechanism

The potential difference (PD)-dependent component of transcellular Mg(2+) uptake in sheep rumen epithelium was studied. Unidirectional (28)Mg(2+) fluxes were measured at various transepithelial PD values, and the unidirectional mucosal-to-serosal (28)Mg(2+) flux (J(Mg)(ms)) was correlated with the PD across the apical membrane (PD(a)) determined by mucosal impalement with microelectrodes. PD(a) was found to be -54 +/- 5 mV, and J(Mg)(ms) was 65.9 +/- 13.8 nmol. cm(-2). h(-1) under short-circuit conditions. Hyperpolarization of the ruminal epithelium (blood-side positive) depolarized PD(a) and, most noticeably, decreased J(Mg)(ms). Further experiments were performed with cultured ruminal epithelial cells (REC). With the aid of the fluorescence probe mag-fura 2, we measured the intracellular free Mg(2+) concentration ([Mg(2+)](i)) of isolated REC under basal conditions at various extracellular Mg(2+) concentrations ([Mg(2+)](e)) and after alterations of the transmembrane voltage. Basal [Mg(2+)](i) was 0.54 +/- 0.08 mM. REC suspended in media with [Mg(2+)](e) between 0.5 and 7.5 mM showed an increase in [Mg(2+)](i) that was dependent on [Mg(2+)](e) and that exhibited a saturable component (Michaelis-Menten constant = 1.2 mM; maximum [Mg(2+)](i) = 1.26 mM). Membrane depolarization with high extracellular K(+) (40, 80, or 140 mM K(+)) and the K(+) channel blocker quinidine (50 and 100 microM ) resulted in a decrease in [Mg(2+)](i). On the other hand, hyperpolarization created by K(+) diffusion (intracellular K(+) concentration > extracellular K(+) concentration) in the presence of valinomycin induced a 15% increase in [Mg(2+)](i). None of the manipulations had any effect on intracellular Ca(2+) concentration and intracellular pH. The results support the assumption that the membrane potential acts as a principal driving force for Mg(2+) entry in REC and suggest that the pathway for this electrodiffusive Mg(2+) uptake across the luminal membrane is a channel or a carrier.

Na transport in sheep rumen is modulated by voltage-dependent cation conductance in apical membrane

The effects of clamping the transepithelial potential difference (PDt; mucosa reference) have been studied in sheep rumen epithelium. Pieces of ruminal epithelium were examined in Ussing chambers, in a part of the experiments combined with conventional intracellular recordings. After equilibration, the tissue conductance (Gt) was 2.50 +/- 0.09 mS/cm(2), the potential difference of the apical membrane (PD(a)) was -47 +/- 2 mV, and the fractional resistance of the apical membrane (fRa) was 68 +/- 2% under short-circuit conditions. Hyperpolarization of the tissue (bloodside positive) depolarized PDa, decreased fRa, and increased Gt significantly. Clamping PDt at negative values caused converse effects on PDa and fRa. All changes were completely reversible. The determination of individual conductances revealed that the conductance of the apical membrane increased almost linearly with depolarization of PDa. The PD-dependent changes were significantly reduced by total replacement of Na. These observations support the assumption of a PD-dependent conductance in the apical membrane that permits enhanced apical uptake of Na even at depolarized PDa. This mechanism appears to be important for the regulation of osmotic pressure in forestomach fluid.

Predictive value of PAI-1 plasma activity and thallium perfusion imaging for restenosis after percutaneous transluminal angioplasty in clinically asymptomatic patients

BACKGROUND

The main long-term complication of percutaneous transluminal coronary angioplasty (PTCA) is restenosis that occurs in 30-50 percent of all primary successful cases. The purpose of this study was to evaluate the predictive value of changes in plasminogen activator inhibitor-1 (PAI-1) activity and of thallium dipyridamole perfusion imaging performed 3 months after successful angioplasty. All patients were asymptomatic at evaluation. The results of these two noninvasive tests were compared with the angiographic outcome after 6 months.

METHOD AND PATIENTS

Twenty-five patients were included in this prospective study. All patients had single vessel disease, successful angioplasty and were free of clinical symptoms 3 months after angioplasty that would suggest late restenosis. In 12/25 patients (48%) angiographic restenosis (percent diameter stenosis >50%) was determined by follow-up angiography 6 months after angioplasty. PAI-1 plasma activity was determined by a functional titration assay and increase or decrease of PAI-1 plasma activity was evaluated between values obtained before and 3 months after angioplasty. In 7/25 (28%) patients PAI-1 plasma activity increased to more than 90% of pre-angioplasty values. This increase correlated with angiographic restenosis evaluated 6 months after angioplasty (sensitivity 42%, specificity 85%, positive predictive value 71%, and negative predictive value 61%). T1-201-perfusion imaging was performed 3 months after angioplasty. This test was indicative for subsequent restenosis in 5/25 patients (sensitivity 33%, specificity 100%, positive predictive value 62%, and negative predictive value 100%). In 10/25 (40%) patients at least one of the two non-invasive tests performed 3 months after angioplasty predicted angiographic restenosis at 6 months: the combined use of PAI-1 and T1-201-perfusion imaging resulted in increased sensitivity (67%) and high specificity (85%).

CONCLUSION

The results of this study indicate that an increase of PAI-1 plasma activity may improve the predictive value for restenosis of T1-201-scintigraphy performed 3 months after angioplasty even in asymptomatic patients.

Dopamine stimulates salivary duct cells in the cockroach Periplaneta americana

This study examines whether the salivary duct cells of the cockroach Periplaneta americana can be stimulated by the neurotransmitters dopamine and serotonin. We have carried out digital Ca2+-imaging experiments using the Ca2+-sensitive dye fura-2 and conventional intracellular recordings from isolated salivary glands. Dopamine evokes a slow, almost tonic, and reversible dose-dependent elevation in [Ca2+]i in the duct cells. Upon stimulation with 10(−)6 mol l-1 dopamine, [Ca2+]i rises from 48+/−4 nmol l-1 to 311+/−43 nmol l-1 (mean +/− s.e.m., N=18) within 200–300 s. The dopamine-induced elevation in [Ca2+]i is absent in Ca2+-free saline and is blocked by 10(−)4 mol l-1 La3+, indicating that dopamine induces an influx of Ca2+ across the basolateral membrane of the duct cells. Stimulation with 10(−)6 mol l-1 dopamine causes the basolateral membrane to depolarize from −67+/−1 to −41+/−2 mV (N=10). This depolarization is also blocked by La3+ and is abolished when Na+ in the bath solution is reduced to 10 mmol l-1. Serotonin affects neither [Ca2+]i nor the basolateral membrane potential of the duct cells. These data indicate that the neurotransmitter dopamine, which has previously been shown to stimulate fluid secretion from the glands, also stimulates the salivary duct cells, suggesting that dopamine controls their most probable function, the modification of primary saliva.

Hyperglycemia regulates the glucose-transport system of clonal choriocarcinoma cells in vitro. A potential molecular mechanism contributing to the adjunct effect of glucose in tumor therapy

Glucose is taken up by tumor cells via sodium-independent facilitated diffusion along a concentration gradient. To examine the regulation of this process by substrate concentration, we investigated the effect of hyperglycemia on the glucose-transport system of choriocarcinoma-derived JAR and JEG-3 cells by culturing them for 24, 48 and 96 hr in medium containing either 5.5 (normoglycemia) or 25 (hyperglycemia) mM D-glucose, respectively. Immunocytochemically, choriocarcinoma cells expressed the high-affinity glucose transporter isoforms GLUT1 and GLUT3. Based on initial uptake measurements using 3-O-[14C]methyl-D-glucose, kinetic parameters were calculated as Km = 15 mM and Vmax = 95 fmol/sec per cell for JAR and Km = 9 mM and Vmax = 64 fmol/sec per cell for JEG-3 cells. In JAR cells cultured under hyperglycemic conditions, uptake rates were significantly increased at 15, 20 and 25 mM exogenous D-glucose concentrations as compared with normoglycemic conditions. This effect was due to an increase in Vmax, whereas Km remained unchanged. Using Northern blotting, GLUT1 mRNA levels were higher but GLUT3 transcripts were reduced upon hyperglycemia. Western blotting revealed elevated GLUT1 and GLUT3 expression under hyperglycemic conditions. Hyperglycemia did not significantly influence the glucose-transport system of JEG-3 cells. We conclude that sustained hyperglycemia stimulates the glucose-transport system of JAR, but not of JEG-3, choriocarcinoma cells in vitro due to changes in GLUT1 and GLUT3 expression levels. We speculate that this mechanism may contribute to the beneficial effects of induced hyperglycemia as an adjuvant in tumor therapy.

Chemoselectively addressable HCan building blocks in peptide synthesis: L-homocanaline derivatives

(S-2-amino-5-(aminooxy)pentanoic acid (L-homocanaline, HCan), a structural analogue of lysine, contains a reactive alkyloxyamine side chain and is therefore considered to react chemoselectively with carbonyl compounds by forming a kinetically stable oxime bond. The chemical synthesis of L-homocanaline starting from protected glutamic acid derivatives is described. Two orthogonally protected homocanaline derivatives were synthesized and their use in standard SPPS procedures was exemplified for the synthesis of a chemoselectively addressable cyclic peptide for use in TASP design. Moreover, the wide range of applications of this unique building block was demonstrated for the chemoselective ligation of an unprotected disaccharide to a HCan containing model peptide resulting in a chimeric glycopeptide structure.

Abdominal calcification in cystic fibrosis with meconium ileus: radiologic-pathologic correlation

BACKGROUND

There is confusion in the radiological literature as to the site of abdominal calcification in cystic fibrosis (CF) with meconium ileus (MI) in neonates.

PURPOSE

To correlate the site of radiographic abdominal calcification with histologic and operative findings.

MATERIALS AND METHODS

A review of clinical, radiographic, surgical and histologic data in 58 neonates with CF and MI.

RESULTS

Abdominal calcification was identified in 15 (26 %) neonates: on an abdominal radiograph in 8 (13 %), at laparotomy in 3 and histologically in 10 (37 %) of the 27 resected specimens. The radiographic pattern of calcification varied from small specks in three cases to small, better-defined areas in two. In the other three patients, the calcification was more extensive and curvilinear. Histologically, calcification was found to be intramural in ten resected specimens, of which two also had intraluminal and one serosal calcification. The more extensive, curvilinear calcification identified radiographically correlated with histologically proven dystrophic intramural calcification. The less marked flecks or discrete areas of radiographic calcification may represent intramural, serosal or intraluminal calcification.

CONCLUSION

Intramural calcification is common microscopically in CF with MI. Extensive radiographic calcification in these patients is more likely to represent intramural rather than serosal or intraluminal calcification.