Retinoic acid modulates prolactin receptor expression and prolactin-induced STAT-5 activation in breast cancer cells in vitro

Two recent papers demonstrate that prolactin plays an important role in the induction and progression of mammary tumours. Retinoids have been shown to be potent inhibitors of breast carcinogenesis. We studied expression of prolactin receptor mRNA in human breast cancer cell lines MCF-7, SKBR-3, T47D and BT-20 treated with and without retinoids using Northern blot and a quantitative polymerase chain reaction (PCR) method. In all cell lines, all-trans- and 9-cis-retinoic acid, as well as the retinoic acid receptor gamma (RAR-gamma) selective agonists CD2325 and CD437 (1 microM), were able to down-regulate prolactin receptor. After 1 h, a significant reduction was detectable and maximal effect was achieved after 24 h of treatment. Pretreatment with retinoic acid also reduced the prolactin-/prolactin receptor-dependent signal transduction and activation of transcription 5 (STAT-5) activation in T47D cells. Cycloheximide failed to abrogate the retinoic acid-induced decline in prolactin receptor mRNA levels, indicating that this effect was not dependent upon continuing protein synthesis. Similarly, no change in the stability of prolactin receptor mRNA was observed during 12 h of retinoic acid treatment. In conclusion, our results demonstrate that retinoids are able to inhibit the expression of prolactin receptor message, which encodes an important growth factor receptor in breast cancer cells. This action could be responsible for the anti-tumour effects of retinoids.

The difference in recognition of terminal tripeptides as peroxisomal targeting signal 1 between yeast and human is due to different affinities of their receptor Pex5p to the cognate signal and to residues adjacent to it

Pex5p is the receptor for the peroxisomal targeting signal 1 (PTS1) that consists of a C-terminal tripeptide (consensus (S/A/C)(K/R/H)(L/M)). Hexadecapeptides recognized by Pex5p from Homo sapiens and Saccharomyces cerevisiae were identified by screening a two-hybrid peptide library, and the targeting ability of the peptides was demonstrated using the green fluorescent protein as reporter. The PTS1 receptors recognized in a species-specific manner a broad range of C-terminal tripeptides, and these are reported herein. In addition, residues upstream of the tripeptide influenced the strength of the interaction in the two-hybrid system as well as in an in vitro competition assay. In peptides interacting with the human protein, hydrophobic residues were found with high frequency especially at positions -2 and -5, whereas peptides interacting with S. cerevisiae Pex5p were more hydrophilic and frequently contained arginine at position -2. In instances where the terminal tripeptide deviated from the consensus, upstream residues exerted a greater influence on the ability of the hexadecapeptides to bind Pex5p.

Role of skeletal muscle in thiazolidinedione insulin sensitizer (PPARgamma agonist) action

Thiazolidinedione (TZD) insulin sensitizers are specific agonists of peroxisome proliferator activated receptor (PPAR)gamma. However, their mechanism of action and the in vivo target tissue(s) that mediate insulin sensitization remain poorly defined. Although PPARgamma messenger RNA expression has been reported in skeletal muscle, the expression of PPARgamma within myocytes in intact muscle tissue has not been examined. An antipeptide PPARgamma antibody was generated; immunohistochemistry was then used to demonstrate that PPARgamma is present within nuclei of myocytes [in both skeletal (white and red fibers) and cardiac tissue (rodent and human)]. The effect of insulin sensitizer treatment on muscle insulin action was studied using ob/ob mice after 4 days dosing with a potent (6 nM PPARgamma Kd) TZD (10 mg/kg x day). 2-deoxyglucose (2-DOG) uptake was then assessed in freshly isolated soleus muscles from lean vs. ob/ob vs. TZD-treated ob/ob mice. In lean mouse muscles, 2-DOG uptake was stimulated by 82%, 95%, 165% (with 25, 100, 2000 microU/ml insulin); muscles from ob/ob were severely insulin resistant (<80% stimulation with 2000 microU/ml insulin). Muscles from TZD-treated ob/ob displayed a normal insulin response with 100 (71%) or 2000 (158%) microU/ml insulin. Additional studies were performed using ZDF rats treated with/without TZD for 7 days. In vivo 2-DOG glucose uptake into soleus, gastrocnemius, and diaphragm muscles was measured during euglycemic-hyperinsulinemic clamp. Compared with lean rats, muscle 2-DOG uptake in ZDF was reduced by 52% (soleus) or 71% (diaphragm). Partial (40-60%) normalization of the reduced 2-DOG uptake was evident in TZD-treated ZDF rats. In contrast to the effect of in vivo treatment on muscle insulin action, preincubation of isolated soleus muscles from naive lean or ob/ob mice for 5 h with 100 nM TZD did not affect insulin-stimulated 2-DOG uptake. We conclude: 1) PPARgamma is expressed in myocytes within skeletal and cardiac muscle. 2) In vivo activation of PPARgamma by treatment of insulin-resistant mice/rats with a potent TZD corrects impaired muscle insulin action. 3) The lack of a direct effect on muscle after 5 h in vitro TZD incubation suggests that changes in insulin action may require a longer duration of PPARgamma activation or that improved muscle insulin sensitivity may result from an indirect in vivo effect of PPARgamma activation (e.g. changes in systemic lipid metabolism).

Development of HIV encephalitis in AIDS and TNF-alpha regulatory elements

Tumor necrosis factor-alpha (TNF-alpha) appears to play an important role in HIV encephalitis (HIVE). TNF2, a polymorphism of TNF-alpha, associates with higher levels of TNF-alpha and severe manifestations of some infections. We studied 44 acquired immunodeficiency syndrome (AIDS) patients with autopsy-proven HIVE and/or HIV leukoencephalopathy (HIVLE) (HIVE/LE) and 30 AIDS patients without HIVE/LE. TNF2 did not associate with presence of HIVE/LE (p > 0.5). Moreover, the TNF-alpha regulatory element TTATTTAT within the 3'-untranslated region was intact in HIVE/LE brains, and HLA-DR3 did not associate with HIVE/LE. Other host factors or, more likely, viral factors may be responsible for the development of HIVE/LE.

Effects of protraction mechanics on the midface

Forty patients with Class III maxillary deficiencies were each treated with a bonded maxillary palatal expansion appliance followed by protraction. Nineteen of the 40 patients were retained with a Frankel III appliance. This group was compared with 24 Class I patients treated solely with bonded expansion appliance mechanotherapy. To determine at which level protraction mechanics affects the maxilla, the Walker's analysis and other cephalometric measurements were used. The protraction group showed significant increases (p <.05) in the following measurements: ANB angle, Wits, A perpendicular to nasion and in sella to A point. Anterior molar movement, without changes in posterior nasal spine or upper incisor to SN, was evident (p <.05). Favorable change in the facial profile was noted. There were no changes in the angles between sella-nasion and its relationship with the Frankfurt, occlusal, palatal, and mandibular planes. Walker's analysis showed no change in the position of orbitale. The control group did not demonstrate any significant changes in the position of the maxillary complex as a result of expansion mechanics. The retention group maintained the position of the maxilla postprotraction. Facial contour was maintained and other profile related variables improved.

The enhancer of polycomb gene of Drosophila encodes a chromatin protein conserved in yeast and mammals

The Polycomb group of genes in Drosophila are homeotic switch gene regulators that maintain homeotic gene repression through a possible chromatin regulatory mechanism. The Enhancer of Polycomb (E(Pc)) gene of Drosophila is an unusual member of the Polycomb group. Most PcG genes have homeotic phenotypes and are required for repression of homeotic loci, but mutations in E(Pc) exhibit no homeotic transformations and have only a very weak effect on expression of Abd-B. However, mutations in E(Pc) are strong enhancers of mutations in many Polycomb group genes and are also strong suppressors of position-effect variegation, suggesting that E(Pc) may have a wider role in chromatin formation or gene regulation than other Polycomb group genes. E(Pc) was cloned by transposon tagging, and encodes a novel 2023 amino acid protein with regions enriched in glutamine, alanine and asparagine. E(Pc) is expressed ubiquitously in Drosophila embryogenesis. E(Pc) is a chromatin protein, binding to polytene chromosomes at about 100 sites, including the Antennapedia but not the Bithorax complex, 29% of which are shared with Polycomb-binding sites. Surprisingly, E(Pc) was not detected in the heterochromatic chromocenter. This result suggests that E(Pc) has a functional rather than structural role in heterochromatin formation and argues against the heterochromatin model for PcG function. Using homology cloning techniques, we identified a mouse homologue of E(Pc), termed Epc1, a yeast protein that we name EPL1, and as well as additional ESTs from Caenorhabditis elegans, mice and humans. Epc1 shares a long, highly conserved domain in its amino terminus with E(Pc) that is also conserved in yeast, C. elegans and humans. The occurrence of E(Pc) across such divergent species is unusual for both PcG proteins and for suppressors of position-effect variegation, and suggests that E(Pc) has an important role in the regulation of chromatin structure in eukaryotes.

Enteropathy-associated T-cell lymphoma and its immunocarcinogenic correlates: case report and review of the literature

We report a case of enteropathy-associated T-cell lymphoma (EATL), diagnosed by small intestine and gastric biopsies, who presented with manifestations of hypocalcemia and malabsorption. Immunological assessment revealed increased expression levels of tumor necrosis factor system components and eotaxin, an observation that is consistent with the cytotoxic T-cell phenotype characteristic of EATL, and decreased numbers of circulating activated (CD8+CD38+ and CD4+CD25+) and suppressor (CD11b+) T cells, a feature which can contribute to lymphomagenesis in patients with celiac disease. The acute clinical presentation of the patient resolved with mineral and vitamin supplementation and a gluten-free diet. The novel immunological findings described are discussed in the context of a review of our current knowledge of the immunopathogenesis of celiac disease and associated intestinal neoplasia.

Interphase cytogenetic study of preoperative core biopsies for the prediction of early serum prostate specific antigen recurrence after radical prostatectomy of clinically localized prostate carcinoma

BACKGROUND

Current clinical and pathologic methods are imprecise in predicting the extent of prostate carcinoma progression. This study was conducted to evaluate the role of interphase cytogenetics (ICG) with chromosome enumeration probes relative to the role of conventional pathologic characteristics in the preoperative prediction of postoperative tumor classification and recurrence of elevated serum concentrations of prostate specific antigen (PSA).

METHODS

The authors performed ICG with enumeration probes for chromosomes 7, 17, and X on 6-microm sections of core biopsies from 75 patients with clinically localized adenocarcinoma of the prostate. Results were compared with pathologic findings (tumor classification, volume, and status of surgical margins) of the corresponding radical prostatectomy specimens and data on serum PSA measurements taken for 72 patients during a follow-up period of up to 42 months (mean, 19.8 months). In addition to ICG, biopsies were reviewed for primary, secondary, highest, and combined Gleason grades, number and bilaterality of positive biopsies, amount of carcinoma (percentage and core length of infiltration), amount of high grade carcinoma, and perineural invasion.

RESULTS

Chromosome categories were unevenly distributed among pathologic tumor classification groups (P = 0.0008) and between groups with positive and negative surgical margins (P = 0.0116). Tumors with aneusomic chromosome numbers had larger volumes than those with eusomy and tetrasomy (P = 0.0022). Kaplan-Meier analysis demonstrated that PSA recurrences (> or = 0.4 ng/mL) were more frequent and observed earlier in patients with detected chromosomal aneusomies than in those with eusomic and tetrasomic chromosome numbers (P < 0.0001). Cox regression analysis indicated that ICG was the most valuable independent factor in predicting PSA recurrences.

CONCLUSIONS

The detection of numeric chromosomal aberrations in preoperative core biopsies is an adverse prognostic sign. Grading based on the quantification of genetic changes might prove useful in the prognostic stratification of patients with clinically localized prostate carcinoma.

A high-capacity assay for activators of glucose incorporation into glycogen in L6 muscle cells

Skeletal muscle is the major tissue responsible for insulin-stimulated glucose uptake and incorporation into glycogen. Skeletal muscle insulin resistance and the resulting postprandial hyperglycemia are hallmarks of non-insulin-dependent diabetes. Therefore, compounds that serve as insulin mimetics or insulin sensitizers in skeletal muscle may be effective in the treatment of diabetes. In order to identify such hypoglycemic agents, a novel assay for activators of glucose incorporation into glycogen has been developed utilizing differentiated L6 muscle cells in 96-well plates. We found that glucose incorporation occurs in a time- and concentration-dependent manner. It is inhibitable by phloretin, an inhibitor of glucose transport. Both insulin and the insulin-mimetic compound pervanadate activate L6 cell glucose incorporation in dose-responsive manners. We conclude that this assay should serve as a high-capacity screen to identify novel compounds that upregulate glucose anabolic metabolism in skeletal muscle. Such chemical entities may prove useful as antidiabetic agents.

DA1-receptor stimulation by fenoldopam in the treatment of postcardiac surgical hypertension

BACKGROUND

Besides adequate analgesia, sedation and ventilation, postcardiac surgical hypertension has to be treated frequently with vasoactive drugs to avoid possible complications. In this study the hemodynamic effects of the DA1-receptor agonist fenoldopam (F) are compared to those of the Ca-channel antagonist nifedipine (N).

METHODS

Postoperatively, 64 CABG-patients with a mean arterial pressure (MAP) of more than 105 mmHg over 10 min were investigated. Patients with compromised ventricular function, insufficient surgical repair, arrhythmia or an ECG unable to detect myocardial ischemia were excluded. The study drugs (initial dosage: F: 0.8; N: 0.3 micrograms.kg-1.min-1) were given continuously via a central venous catheter to reduce and to maintain the MAP between 80 and 95 mmHg. Hemodynamic parameters were determined using thermodilution technique.

RESULTS

A significant reduction of the MAP (F: from 121 +/- 11 to 83 +/- 4, N: from 119 +/- 8 to 82 +/- 9 mmHg) and of the calculated systemic vascular resistance (SVR) (F: 2110 +/- 500 to 970 +/- 200, N:1980 +/- 660 to 1020 +/- 300 dyn.s.cm-5) were noted in both groups, whereby in the F group the therapeutic goal could be achieved more quickly with the dosage regimen chosen. As a result, a marked increase of heart rate, cardiac index and stroke volume index could be observed, which was more pronounced due to the initially stronger decrease of SVR with F. There was also a stronger decrease of pulmonary vascular resistance in the F group, but the indices of right ventricular function did not differ between the groups.

CONCLUSION

Fenoldopam seems to be an efficient alternative to nifedipine, especially because of its more rapid onset of action.

alpha-1-Microglobulin: epidemiological indicator for tubular dysfunction induced by cadmium?

OBJECTIVES

To evaluate the suitability of alpha-1-microglobulin as a marker for cadmium induced renal dysfunction.

METHODS

alpha-1-Microglobulin was studied in a cross sectional survey in relation to the body burden of cadmium. Concentrations of alpha-1-microglobulin in 24 h urine of 831 people aged 2-87 years were analysed in association with urinary cadmium excretion, cadmium blood concentration, age, sex, occupational and smoking history, and estimated creatinine clearance. Participants came from a population residentially exposed to cadmium and from two control populations matched for socioeconomic status.

RESULTS

The excretion of alpha-1-microglobulin/24 h ranged from 0.1 mg to 176.3 mg and 44.4% of samples showed concentrations near the detection limit. Ordinal logistic regression analysis of people of all ages identified a high risk only for males compared with females (odds ratio (OR) 2.14; 95% confidence interval (95% CI) 1.56 to 2.94), age group, and duration of living on contaminated soil (OR 1.03/year; 95% CI 1.02 to 1.04), but not urinary cadmium excretion (OR 1.30; 95% CI 0.96 to 1.77) as significant predictors. For people < or = 50 years of age a weaker effect of sex (OR 1.76; 95% CI 1.13 to 2.73) and age group and an effect of similar magnitude for the duration of soil exposure (OR 1.03; 95% CI 1.01 to 1.04) were found. Also, the urinary cadmium excretion (OR 2.26; 95% CI 1.38 to 3.70) and occupational exposure (OR 1.71; 95% CI 1.03 to 2.83) were found to be significant in this younger age group. The estimated creatinine clearance had no significant impact on the alpha-1-microglobulin excretion.

CONCLUSION

alpha-1-Microglobulin is a suitable marker for early tubular changes only for people < or = 50 years. It may not be sufficiently specific for cadmium, and therefore not a suitable surrogate for cadmium exposure in epidemiological studies.

Localization of Staphylococcus aureus in infected airways of patients with cystic fibrosis and in a cell culture model of S. aureus adherence

Staphylococcus aureus causes chronic respiratory tract infections in patients with cystic fibrosis (CF). Using immunofluorescence and scanning and transmission electron microscopy we located S. aureus in lung specimens of three infected CF patients, in a nasal polyp of one CF patient, and in a suspension cell culture system of primary nasal epithelial cells in vitro. Very little of S. aureus was attached to the lung epithelium, whereas abundant S. aureus was detectable in the mucus of obstructed airways. Similarly, S. aureus adhered to components of secreted mucus on primary nasal epithelial cells of CF patients and healthy control subjects, grown as cell balls in vitro (bacteria/cell +/- SD: CF: 21.9 +/- 1.5; controls: 22. 0 +/- 5.8). Mucus depletion of cell balls prior to incubation with S. aureus resulted in a significantly reduced binding (bacteria/cell +/- SD: CF: 4.2 +/- 0.3; P < 0.001; controls: 5.0 +/- 1.3; P < 0. 007). Binding of S. aureus to cell balls from CF patients or control subjects did not differ significantly. When cell balls were treated with human neutrophil elastase, hypersecretion caused removal of S. aureus from cell-associated mucus. The results suggest that S. aureus adheres primarily to mucus components of the respiratory epithelium and that significant differences do not exist in binding of S. aureus to CF or non-CF cells.

Changing bacterial ecology during a five-year period of selective intestinal decontamination

The development of bacterial resistance during selective decontamination of the digestive tract (SDD) is controversial. We studied effects on bacterial resistance one year before and during a randomized, placebo-controlled trial of SDD in a surgical intensive care unit. We randomized patients within two different topical regimens (PTA, PCA) or placebo, administered four-times daily to both the oropharynx and gastrointestinal tract. All patients received intravenous ciprofloxacin (200 mg b.d.) for four days. Both SDD regimens successfully reduced aerobic Gram-negative intestinal colonization. There was no increase in resistance of Enterobacteriaceae or Pseudomonas aeruginosa. Acinetobacter calcoaceticus developed multi-resistance over one year, but differences between groups were not significant. We detected a shift towards Gram-positive organisms. Oxacillin-resistant Staphylococcus aureus increased in concert with ciprofloxacin resistance, from 17 to 80.7%, and frequencies of resistance were significantly higher in SDD patients (P < 0.001). Resistance of coagulase-negative staphylococci (CNS) to oxacillin increased initially (25 to 66.9%), but values returned to baseline in controls. Ciprofloxacin resistance in CNS remained higher (P < 0.001) in SDD-treated patients (52.5 vs. 23.3%). The incidence of late respiratory tract infections was unaltered by the prophylactic regimen (SDD 35.2%; Placebo 41.2%; n.s.). We cannot recommend SDD as a prophylactic tool in critically ill patients.

A novel relative of the very-long-chain acyl-CoA synthetase and fatty acid transporter protein genes with a distinct expression pattern

Based on its relationship to very-long-chain acyl-CoA synthetase (VLACS), we have cloned and identified a novel, VLACS-related (VLACSR) cDNA from mouse liver. The 2067-bp open reading frame encodes a 689-amino-acid protein with a predicted molecular mass of 76.2 kDa. The carboxy-terminal 500 amino acids of VLACSR show 48% identity and 70% similarity to mouse VLACS and 43% identity and 60% similarity to mouse fatty acid transporter (FATP), respectively. In addition, a partial cDNA of the human VLACSR ortholog was identified. By Northern blot analysis, a 2.6-kb VLACS mRNA was highly abundant only in mouse liver. Low levels of shorter mRNAs were present in brain, lung, testes, and spleen (2.5 kb) and in skeletal muscle (2.2 kb). In heart, but not in kidney, transcripts undetectable by Northern blot analysis could be demonstrated by RT PCR. Southern blot analysis indicated single-copy VLACSR genes in the mouse and human genomes.

Learning disabilities with and without attention-deficit hyperactivity disorder: parents' and teachers' perspectives

Our objective was to delineate the educational and behavioral differences between learning disabled children with and without attention-deficit hyperactivity disorder (ADHD). A restrospective (TROHOC) multimeasure comparative design was employed. Parents' and teachers' questionnaires (ANSER system) pertaining to attention-activity, associated behaviors, and scholastic achievements were compared. Parents' questionnaires failed to distinguish between the two groups. Teachers' questionnaires were significantly more sensitive. Significant correlations between educational achievements and attention-activity and associated behaviors scores among children with learning disabilities were evident, no such correlations were found in the group with learning disability with ADHD. The factor analysis identified different educational and behavioral aggregates with language related difficulties and externalizing behaviors more typically aggregated in the learning disabled group with ADHD and recall deficit and internalizing/neurotic behaviors in the group with learning disability only. ADHD appears to be an associated comorbidity and not necessarily a specific learning deficit. However, children with learning disability with ADHD possibly have a different underlying neurocognitive pattern than their peers with learning disabilities only.

Activation-dependent expression of the insulin-like growth factor binding protein-2 in human lymphocytes

The expression of the insulin-like growth factor binding protein-2 (IGFBP-2) was assayed in mononuclear cells originating from different organs of the immune system. All mononuclear cells studied did express IGFBP-2, but the expression level was found to be dependent on the cell type and origin of the cell. T cells showed a higher expression of IGFBP-2 mRNA than did B cells, and CD34+ stem cells expressed IGFBP-2 mRNA at a high level. Expression was highest in bone marrow and thymus. Stimulation of peripheral mononuclear cells resulted in a marked increase of IGFBP-2 mRNA and also intracellular IGFBP-2, as analysed by fluorescence staining. This increase parallels the increase of other known T-cell activation markers. Furthermore, the increase of intracellular IGFBP-2 seems to precede T-cell blast formation and all T cells in active phases of the cell cycle have high levels of IGFBP-2. Our results provide a basis for further investigations on the contribution of the IGF-system to the regulation of T-cell proliferation and differentiation. IGFBP-2, in particular, may have an important influence in the regulation of T-cell activation and proliferation.

cDNA cloning and mRNA distribution of a mouse very long-chain acyl-CoA synthetase

The interaction of the adrenoleukodystrophy protein (ALDP), mutated in the peroxisomal disorder X-linked adrenoleukodystrophy, and the very long-chain acyl-CoA synthetase (VLACS), the enzyme whose function is missing in this disease, remains obscure. As a first step to studying this interaction in wild type versus ALDP-deficient mice, we have cloned a VLACS cDNA from mouse liver. The 1860 bp open reading frame encodes a 620 amino acid protein with a predicted molecular mass of 70.3 kDa. By Northern blot analysis, a 2.6 kbp VLACS mRNA was highly abundant in liver and kidney and present at low levels in brain and testes. By RT-PCR VLACS mRNA was also detected in heart and lung but remained undetectable in skeletal muscle and spleen. In contrast to the peroxisomal beta-oxidation marker acyl-CoA oxidase, whose mRNA level steadily increases during brain development, the VLACS transcript was found at a constant low level from embryo through adulthood, suggesting that additional isoforms may exist in brain.

Solid materials with high dielectric constants for hyperthermia applications

The manufacture of solid components with high permittivities epsilon r of 1-100 and differing conductivities sigma of 0-1.0 S/m has practical significance for fabricating applicators and phantoms in radiofrequency hyperthermia. For this purpose, various plastics (resins, polyurethane and silicone) were combined with additives (graphite and metal powder) and tested to assess their radiofrequency and mechanical characteristics and to identify manufacturing problems. Most of the plastics could be made highly dielectric and conductive by adding graphite in the range of muscle tissue (i.e. epsilon r approximately 80, sigma approximately 0.8 S/m). However, there are major differences between the materials with respect to mechanical behaviour, durability, feasibility of manufacture, and reproducibility. Manufacturing water-equivalent plastics (low conductivity sigma < 0.05 S/m and epsilon r value of 70-80) is particularly difficult. A less filled polyester resin in which concentration of brass powder can achieve an epsilon r value of up to 100 at low conductivity proved to be the only suitable medium. Such a plastic can be used for future applicator designs. Other materials of interest include plastics equivalent to lossy media (e.g. sigma = 0.45-0.55 S/m, epsilon r = 70-80), fat-equivalent plastics (polyurethane with graphite) and higher dielectric flexible plastics (silicone with brass powder).