Chloride distribution in Aplysia neurones

1. The intracellular Cl(-) concentration (Cl(i)) and the membrane potential (E(m)) were measured in the medial pleural neurones of Aplysia under various experimental conditions designed to determine the Cl(-) conductance of the neurones and investigate the possibility of an active Cl(-) transport.2. The magnitude of the Cl(-) conductance of the cell depends on the experimental conditions.3. In normal sea water, large changes of E(m) produced by passing current across the cell membrane caused no change of Cl(i), suggesting that the Cl(-) conductance was low. Similarly, moderate changes of E(Cl) produced by decreasing Cl(o) or increasing Cl(i) had little or no effect on E(m).4. A high Cl(-) conductance was observed in high K(o) or very low Cl(o). It was greatly reduced if the external Ca(2+) was replaced by Co(2+), or in the presence of tubocurarine, or if the experiment was performed on an isolated cell soma. The high Cl(-) conductance is therefore attributed to the release of ACh and perhaps other transmitters from synaptic terminals.5. High concentrations of tetraethylammonium ions or procaine induced a depolarization of the cell, but a decrease of Cl(i). The rate of fall of Cl(i) was increased by lowering external K(+) or raising external Ca(2+), and was decreased by replacing external Ca(2+) by Co(2+).6. NH(4) (+) ions applied externally had effects similar to those of K(+) ions. In situations in which intracellular NH(4) (+) might be increased a fall in Cl(i) was observed.7. The changes of Cl(i) caused by TEA, procaine, or internal NH(4) (+) occur against the driving force for passive Cl(-) movements. They are still observed in isolated cell bodies, and cannot be attributed to the activation of synaptic channels.8. Some interpretations of these anomalous Cl(-) movements are discussed which could also account for the difference between E(Cl) and E(m) observed under normal conditions.

Carbon nanofibers and carbon nanotubes sensitize prostate and bladder cancer cells to platinum-based chemotherapeutics

Recent data suggest that carbon nanomaterials can act as antitumor agents themselves by increasing the efficiency of cytotoxic agents when applied in combination. Here, carbon nanofibers (CNFs) and multi-walled carbon nanotubes (CNTs) were investigated regarding their impact on cellular function, cellular uptake and ability to sensitize cancer cells of urological origin to the conventional chemotherapeutics cisplatin and carboplatin. CNFs and CNTs (1-200 microg/ml) showed a low to moderate impairment of cellular function with CNFs being more deleterious than CNTs. Inhibition of cellular viability by the nanomaterials was about 20% at most. In combinatory treatments, CNFs and CNTs markedly enhanced the effects of cisplatin and carboplatin on cellular viability by 1.2- to 2.8-fold in prostate, bladder and cisplatin-resistant prostate cancer cells in comparison to the individual effects of the chemotherapeutics. Particularly the cell viability-diminishing effect of CNFs alone and in combination with the chemotherapeutics was more pronounced with dispersions prepared with human serum albumin than with phospholipid-polyethylene glycol. Albumin might mediate the cellular uptake of carbon nanomaterials which was underlined by the co-localization of albumin and carbon nanomaterials along the cellular surface as evidenced by fluorescence microscopy. Transmission electron microscopy revealed that both carbon nanomaterials were internalized by cancer cells, thereby possibly leading to an enhanced accumulation of the chemotherapeutic drugs. In fact, CNFs enhanced the cellular accumulation of carboplatin by 28% as compared to the single treatment with carboplatin. In conclusion, carbon nanomaterial-based applications could present a new strategy to overcome chemoresistance by sensitizing cancer cells to conventional chemotherapeutics.

Enhanced inhibition of bladder cancer cell growth by simultaneous knockdown of antiapoptotic Bcl-xL and survivin in combination with chemotherapy

The overexpression of antiapoptotic genes, such as Bcl-xL and survivin, contributes to the increased survival of tumor cells and to the development of treatment resistances. In the bladder cancer cell lines EJ28 and J82, the siRNA-mediated knockdown of survivin reduces cell proliferation and the inhibition of Bcl-xL sensitizes these cells towards subsequent chemotherapy with mitomycin C and cisplatin. Therefore, the aim of this study was to analyze if the simultaneous knockdown of Bcl-xL and survivin might represent a more powerful treatment option for bladder cancer than the single inhibition of one of these target genes. At 96 h after transfection, reduction in cell viability was stronger after simultaneous inhibition of Bcl-xL and survivin (decrease of 40%-48%) in comparison to the single target treatments (decrease of 29% at best). Furthermore, simultaneous knockdown of Bcl-xL and survivin considerably increased the efficacy of subsequent chemotherapy. For example, cellular viability of EJ28 cells decreased to 6% in consequence of Bcl-xL and survivin inhibition plus cisplatin treatment whereas single target siRNA plus chemotherapy treatments mediated reductions down to 15%-36% only. In conclusion, the combination of simultaneous siRNA-mediated knockdown of antiapoptotic Bcl-xL and survivin-a multitarget molecular-based therapy-and conventional chemotherapy shows great potential for improving bladder cancer treatment.

siRNA-mediated inhibition of antiapoptotic genes enhances chemotherapy efficacy in bladder cancer cells

BACKGROUND

The up-regulation of antiapoptotic B-cell CLL/lymphoma 2 (BCL2), BCL2-like 1 (BCLXL), X-linked inhibitor of apoptosis (XIAP) and survivin is one mechanism by which cancer cells develop resistance towards chemotherapeutics. Therefore, the knockdown of these four genes could sensitise bladder cancer (BCa) cells towards chemotherapy.

MATERIALS AND METHODS

BCL2, BCLXL, XIAP and survivin were inhibited using siRNAs--either one target-alone or all four targets simultaneously--in EJ28 and J82 BCa cells. After 24 h, cells were treated with mitomycin C or cisplatin. Treatment effects were analysed regarding cell viability, cell count and apoptosis induction.

RESULTS

Knockdown of BCLXL and survivin, as well as the simultaneous inhibition of all four antiapoptotic genes, sensitised EJ28 and J82 cells towards mitomycin C and cisplatin.

CONCLUSION

Since the contribution of one antiapoptotic gene to chemotherapy response can vary between BCa cell lines, the simultaneous knockdown of multiple inhibitors of apoptosis might represent a more promising option for enhancing chemotherapy efficacy in BCa treatment.

Simultaneous siRNA-mediated knockdown of antiapoptotic BCL2, Bcl-xL, XIAP and survivin in bladder cancer cells

Bladder cancer (BCa) represents the ninth most common malignancy worldwide. Despite intensive treatment with surgery and chemotherapy the prognosis for BCa patients particularly at advanced stages is poor. The ability to evade apoptosis is a hallmark of cancer cells. Since the antiapoptotic genes BCL2, Bcl-xL, XIAP and survivin are frequently upregulated in BCa tissues, their combined siRNA-mediated knockdown might be more potent in decreasing BCa growth than the single inhibition of one target. Against each target two siRNAs were selected that specifically reduced the mRNA and protein levels of their appropriate target in EJ28 and J82 BCa cells. Inhibition of survivin provoked the strongest antiproliferative effect of all single target treatments, for example cell counts decreased by 50%. Simultaneous targeting of all four antiapoptotic genes downregulated expression levels of all targets and mediated significant reductions in cell viability and cell counts as well as induction of apoptosis. In EJ28 cells, combined knockdown of BCL2, Bcl-xL, XIAP and survivin caused a 2.5-fold enhancement in apoptosis rate and reduced cellular viability by 40%. Therefore, simultaneous knockdown of antiapoptotic BCL2, Bcl-xL, XIAP and survivin may represent a promising treatment option for bladder cancer.

Multitarget siRNA inhibition of antiapoptotic genes (XIAP, BCL2, BCL-X(L)) in bladder cancer cells

BACKGROUND

The knockdown of XIAP, BCL2 and BCL-X(L) by siRNAs represents a promising treatment option for bladder cancer (BCa) since the overexpression of antiapoptotic genes is often associated with tumor progression and treatment resistance.

MATERIALS AND METHODS

EJ28 BCa cells were transfected with siRNAs--separately and combined--followed by analysis of target expression, viability, clonogenic survival, apoptosis and cell cycle. Furthermore, a possible chemosensitization by siRNA pretreatment was investigated.

RESULTS

The siRNA-mediated inhibition of these targets--either separately or combined--reduced the targets' expression, reduced cell growth and sensitized cells to a subsequent chemotherapy.

CONCLUSION

Since tumor cells may bypass the inhibition of a single gene by changing their expression profile, e.g. switch from BCL2 to BCL-X(L), the combined knockdown of multiple genes of the same pathway might be more effective in killing cancer cells. The siRNAs used represent appropriate tools for this aim since they reduced their targets' expression significantly and long-lastingly.

Antisense-mediated inhibition of survivin, hTERT and VEGF in bladder cancer cells in vitro and in vivo

Since cancer cells are characterised by multiple genetic alterations the single inhibition of one tumour- associated gene might not be sufficient as a therapeutic strategy. We examined the effects of a combined inhibition of survivin, human telomerase reverse transcriptase (hTERT) and vascular endothelial growth factor (VEGF) with antisense oligodeoxynucleotides (AS-ODNs) and small interfering RNAs (siRNAs) in EJ28 and 5637 bladder cancer (BCa) cells. Following verification of the uptake of intraperitoneally applied fluorescence-labelled AS-ODNs and siRNAs in subcutaneous BCa xenografts, the target-directed constructs were tested as single agents in SCID mice bearing subcutaneous EJ28. Simultaneous inhibition of two of the selected transcripts significantly enhanced cell viability reduction compared to the controls consisting of a target directed construct and an appropriate control construct without any homology to the human genome. The uptake of both antisense inhibitor types in the subcutaneous BCa was achieved even without a carrier. In vivo studies with 9 consecutive intraperitoneal injections with 20 mg/kg AS-ODNs or 4.6 mg/kg siRNAs revealed the biocompatibility of both antisense inhibitor types and showed anti-tumoural activity of the AS-ODNs used.

Carbon nanotubes filled with a chemotherapeutic agent: a nanocarrier mediates inhibition of tumor cell growth

Aim: In this paper, carbon nanotubes (CNTs) are presented as feasible carriers for carboplatin, a therapeutic agent for cancer treatment. The drug was introduced into CNTs to demonstrate that they are suited as nanocontainers and nanocarriers and can release the drug to initialize its medical virtue. Method: The filling was accomplished by a wet-chemical approach after the CNTs were opened. The effect on cell proliferation and cytotoxicity of the carboplatin-filled CNT was investigated by using a viability assays. Results: Using different analysis methods such as electron energy loss spectroscopy and x-ray photoelectron spectroscopy the structure of carboplatin incorporated into the CNTs was found to be retained. In vitro studies showed that carboplatin-filled CNTs inhibited growth of bladder cancer cells whereas unfilled, opened CNTs barely affected cancer cell growth. Conclusion: A reversible filling–emptying process could be performed successfully within this work. This highlights the potential of CNTs for applications in the field of drug delivery.

Are overexpressed alternative survivin transcripts in human bladder cancer suitable targets for siRNA-mediated in vitro inhibition?

In order to reduce side effects of survivin-inhibiting anticancer therapies, we determined the expression of the survivin transcripts survivin-wild-type (survivin-wt), survivin-DeltaEx3 (DeltaEx3) and survivin-2B (2B) in cryo-preserved tumor and non-malignant bladder tissues (18 tumor and 22 non-malignant samples, including 17 autologous tissue pairs) by quantitative PCR. Furthermore, we investigated the biological effects following specific inhibition of the alternative transcripts DeltaEx3 and 2B in bladder cancer (BCa) cells. In BCa and non-malignant bladder tissues survivin-wt was the quantitatively dominant transcript followed by DeltaEx3 and 2B. The mean mRNA expression of DeltaEx3 (0.37 vs. 0.06 zmol/amol GAPDH, respectively) and 2B (0.13 vs. 0.01 zmol/amol GAPDH, respectively) was significantly higher in BCa compared to non-malignant bladder tissues, indicating their accessibility for an expression inhibition in BCa cells. Effective and long-lasting small interfering RNA-mediated inhibition of one alternative survivin transcript caused lower cell growth reduction effects (apoptosis induction, cell cycle arrest, colony formation) compared to simultaneous inhibition of multiple survivin transcripts including survivin-wt. Inhibition of one alternative survivin transcript increased the apoptosis rate by 11% vs. 33-46% when reducing several survivin transcripts. We observed no G2/M arrest or reduction of cell colony formation after inhibiting one alternative survivin transcript. Reduction of cell viability by the chemotherapeutics cisplatin, mitomycin C or gemcitabine was stronger in combination with inhibition of several survivin transcripts than in combination with the reduction of one alternative survivin splice variant. Furthermore, reducing one alternative transcript caused chemosensitization to only one chemotherapeutic agent in contrast to inhibition of several survivin transcripts. Therefore, the alternative survivin transcripts DeltaEx3 and 2B do not represent reasonable targets for anticancer, at least BCa, treatment.

[Working hours and job satisfaction among physicians in hospitals and general practice in Munich. Results of an anonymous questionnaire]

PURPOSE

In autumn 2004 the local association of physicians (Arztlicher Kreis- und Bezirksverband München) performed a survey among employed physicians in Munich on working hours and working conditions. The aim of the study was to assess the extent to which the German law on working hours is actually implemented in employed physicians, and to obtain information about their work satisfaction.

METHODS

A questionnaire was sent to all employed physicians in hospitals and medical practices. Participants were asked to give anonymous information and send it back per mail.

RESULTS

In total, 2450 out of 5461 physicians took part in the survey. 45% reported that their working hours do not meet the German law on working hours of 1994. 44.4% stated that overtime is not fully recognized by their employers. 43.5% think the job would become more attractive if the law was implemented. 63.3% expect an income loss with the implementation. 53.7% are thinking about quitting their job. For 59.9% the burden of long working hours is an important reason for this. Women are more likely to be given a limited employment contract than men, and their overtime is more rarely recognized in full.

CONCLUSION

Many employed physicians in Munich are dissatisfied with their job. The high burden of long working hours is a main reason for this.

Functional analyses of C13orf19/P38IP in prostate cell lines

Human C13orf19 was previously identified to be downregulated in prostate cancer (PCa) but its function is unknown to date. In the present study, C13orf19 mRNA expression was inhibited by siRNA transfection. Furthermore, a possible regulation by androgens and the previously postulated interaction with p38 MAP kinase (p38MAPK) was investigated. The siRNA-mediated downregulation of the C13orf19 mRNA expression in the prostate cell lines PC-3 and BPH-1 was examined by quantitative PCR. Cellular viability, apoptosis, cell cycle distribution and clonogenic survival were investigated. In addition, the effects of C13orf19 downregulation in combination with chemotherapy on overall cell survival were studied. The inhibition of C13orf19 mRNA expression to 12% (after 12 h) and 55% (after 96 h) in PC-3 cells attested to a strong and persistent molecular effect provoked by the siRNA-D5 construct. However, no obvious effects on doubling time and cellular morphology were observed. Cell cycle distribution, clonogenic survival, apoptosis and cell viability showed no alterations, even after combining siRNA transfection with chemotherapy. Therefore, it can be concluded that the reduced expression of C13orf19 in PCa is not involved in the malignant transformation of the cells. A possible androgen dependence of C13orf19 mRNA expression was investigated by treating LNCaP cells with the androgen R1881 and in combination with the antiandrogen, bicalutamide. C13orf19 is expressed independently of the androgen. To analyze the putative interaction between C13orf19 and p38MAPK, PC-3 and BPH-1 cells were treated with the p38MAPK inhibitor, SB203580, and C13orf19 mRNA expression was examined. Additionally, the expression and phosphorylation status of p38MAPK after the inhibition of C13orf19 was investigated by Western blotting. No interaction between C13orf19 and p38MAPK was identified. Therefore, the gene should forthwith be named C13orf19 or Fam48A and not P38IP.

CandidaDB: a genome database for Candida albicans pathogenomics

CandidaDB is a database dedicated to the genome of the most prevalent systemic fungal pathogen of humans, Candida albicans. CandidaDB is based on an annotation of the Stanford Genome Technology Center C.albicans genome sequence data by the European Galar Fungail Consortium. CandidaDB Release 2.0 (June 2004) contains information pertaining to Assembly 19 of the genome of C.albicans strain SC5314. The current release contains 6244 annotated entries corresponding to 130 tRNA genes and 5917 protein-coding genes. For these, it provides tentative functional assignments along with numerous pre-run analyses that can assist the researcher in the evaluation of gene function for the purpose of specific or large-scale analysis. CandidaDB is based on GenoList, a generic relational data schema and a World Wide Web interface that has been adapted to the handling of eukaryotic genomes. The interface allows users to browse easily through genome data and retrieve information. CandidaDB also provides more elaborate tools, such as pattern searching, that are tightly connected to the overall browsing system. As the C.albicans genome is diploid and still incompletely assembled, CandidaDB provides tools to browse the genome by individual supercontigs and to examine information about allelic sequences obtained from complementary contigs. CandidaDB is accessible at http://genolist.pasteur.fr/CandidaDB.

[Obesity in children and adolescents in Germany. Significant and persistent increase of prevalence. Appeal to treatment]

In Germany, the number of overweight children and adolescents is increasing. The increase in the prevalence of obesity shows considerable regional differences. Related to recent German reference data with an expected prevalence of 3%, we find today in some regions a prevalence of 7% in 5- to 6-year-olds and 8% in 13- to 15-year-olds. While the reasons for this development are not fully clear, it may be assumed that the increase in physical inactivity, together with the ready availability of an abundance of high-energy foods are significant contributing factors. A large percentage of children and adolescents suffering from obesity also have considerable co-morbidity. It is to be expected that this will in the future considerably increase the financial burden on public health care and society as a whole. Effective prevention and therapeutic countermeasures are necessary to deal with this problem.

[Ever more children and adolescents are overweight. How can the obesity epidemic be stopped?]

In Germany, the number of overweight children and adolescents is increasing. The increase in the prevalence of obesity shows considerable regional differences. Related to recent German reference data with an expected prevalence of 3%, we find today in some regions a prevalence of 7% in 5- to 6-year-olds and 8% in 13- to 15-year-olds. While the reasons for this development are not fully clear, it may be assumed that the increase in physical inactivity, together with the ready availability of an abundance of high-energy foods are significant contributing factors. A large percentage of children and adolescents suffering from obesity also have considerable co-morbidity. It is to be expected that this will in the future considerably increase the financial burden on public health care and society as a whole. Effective prevention and therapeutic countermeasures are necessary to deal with this problem.

Thomsen-Friedenreich antigen presents as a prognostic factor in colorectal carcinoma: A clinicopathologic study of 264 patients

BACKGROUND

Up to now, the expression of the tumor-associated Thomsen-Friedenreich (TF) antigen in colorectal carcinoma has not been thoroughly investigated with particular emphasis on its correlation with established clinicopathologic characteristics and classifications as well as its prognostic relevance.

METHODS

Formalin fixed, paraffin embedded specimens from 264 patients with colorectal carcinoma were stained using an avidin-biotin complex-peroxidase assay. As primary monoclonal antibodies (MAbs), A78-G/A7, which binds to TFalpha and TFbeta antigen irrespective of its carrier, and BW835, which detects TFalpha on MUC1 repeat peptide, were applied.

RESULTS

MAbs A78-G/A7 and BW835 labeled 64.8% and 58. 0%, respectively, of carcinomas. None of the binding patterns correlated with gender, tumor localization, or growth type. Only BW835 reactivity exhibited a significant correlation with increasing pTNM staging and histologic grading. Staining of the MAb A78-G/A7 was significantly stronger in carcinomas that contained a mucinous component. In univariate survival analysis, in addition to pTNM staging and histologic grading, reactivity with A78-G/A7 as well as BW835 were significantly correlated with lower survival probability. Multivariate analysis according to the Cox proportional hazards model revealed only pTNM staging, histologic grading, and A78-G/A7 staining to be independent prognostic factors.

CONCLUSIONS

According to these results, TF disaccharide represents a cancer-associated antigen in colorectal carcinoma that exhibits qualities of a prognostic marker. As demonstrated by BW835 staining, it is obviously coexpressed with MUC1 peptide core in a great number of cases. These results suggest that TF, in addition to MUC1, might also serve as a useful target antigen in the treatment of patients with colorectal carcinoma.

Prognostic impact of p21/waf1/cip1 in colorectal cancer

In addition to the tumor suppressor gene p53, Cyclin Dependent Kinases (CDK) are well known to influence the cell cycle in normal human tissues and various neoplasias as well. The purpose of our present study was to evaluate the expression of the CDK-inhibitor p21/waf1/cip1 in colorectal cancer with special emphasis on the prognostic impact. Between 1985 and 1991, 294 patients (median age, 65 years) underwent surgical operative therapy for colorectal cancer. Formalin-fixed and paraffin-embedded tumor specimens were investigated. For immunohistochemistry the Catalysed Reporter Deposition (CARD) technique was performed. The survival probability was calculated and possible prognostic risk factors were tested using multivariate analysis. The p21/ waf1/cip1 staining pattern was positive in 197 (67%) specimens and negative in 97 (33%) samples. No significant correlation could been calculated between p21/waf1/cip1 expression and other variables such as age, sex, WHO-Classification, localisation, grading, TNM-classification or UICC-stage. Patients with a positive staining reaction had a significantly better survival (p < 0.0052). Moreover, p21/waf1/cip1 was shown to be an independent prognostic parameter by multivariate analysis (p < 0.022). In contrast with these findings, the p53 tumor status had no impact on survival. P21/ waf1/cip1 appears to be an independent prognostic parameter in colorectal cancer and is associated with a favorable survival. This feature may be related to a cell cycle arrest in the G1 phase induced by p21/waf1/cip1, resulting in lower tumor cell proliferative activity.

Synthesis and secretion of plasmalogens by type-II pneumocytes

Alveolar surfactant (exposed to air and therefore a prime target of air oxidants) is supplied with antioxidants during its intracellular formation on type-II pneumocytes [Rüstow, Haupt, Stevens and Kunze (1993) Am. J. Physiol. 265, L133-L139]. Plasmalogens can protect animal cells against lipid peroxidation caused by u.v. radiation. It has been suggested that plasmalogens play a direct role in protecting animal cell membranes against oxidative stress [Zoeller, Morand and Raetz (1988) J. Biol. Chem. 263, 11590-11596]. We investigated biosynthesis and secretion of plasmalogens and phospholipids by type-II cells of adult rat lungs. The plasmalogens of type-II cells consist of 93% ethanolamine plasmalogens (EthPlas) and 7% choline plasmalogens (ChoPlas). Plasmalogens isolated from alveolar surfactant, however, consist of 36.5% ChoPlas and 63.5% EthPlas. The different incorporation rates of [14C]hexadecanol into both types of plasmalogen by type-II pneumocytes are reflected in the relative proportions of their total cellular plasmalogen content. Type-II cells cultured in the presence of labelled hexadecanol or labelled hexadecylglycerol and of labelled palmitate secrete labelled ChoPlas and labelled phospholipids, both spontaneously and in response to isoprenaline. The spontaneous and stimulated secretion rates of labelled ChoPlas are 3-6 times higher than those of labelled EthPlas. This higher relative secretion rate of ChoPlas corresponds to its higher proportion in the total plasmalogen content of alveolar surfactant compared with type-II cells. Added extracellular surfactant-specific protein A inhibits the secretion of plasmalogens as well as that of phospholipids by type-II cells. The molecular species of EthPlas and ChoPlas isolated from type-II cells or lung lavage do not differ significantly and consist mainly of molecular species containing poly-unsaturated fatty acids. We conclude that ChoPlas are secreted partly as integral constituents of the alveolar surfactant. Type-II cells select between both types of plasmalogens for secretion as a constituent of surfactant. The intramolecular sorting signal presumably is the choline moiety.

Turner syndrome: final height, glucose tolerance, bone density and psychosocial status in 25 adult patients

The information available on the medical and psychosocial status of patients with Turner syndrome beyond the paediatric age group is scarce. We therefore studied 25 unselected women with cytogenetically proven Turner syndrome (age 20-50 years), who never received any growth-promoting therapy, and ten control women (25-48 years). In addition to anthropometric measurements, an oral glucose tolerance test was performed, auto-antibodies to endocrine tissues were studied, bone mineral density of the forearm was measured by single photon densitometry, and information about the psychosocial distress of the patients was obtained. Adult height averaged 148.7 +/- 1.1 cm (mean +/- SE), which was 16 cm below the mean of adult women from a similar background. In Turner patients, final height correlated significantly with mid-parental height (final height = 0.67 x MPH + 32.1; r = 0.69). Body mass index was increased in Turner patients (25.6 +/- 1.3 kg/m2) compared to controls (21.4 +/- 0.6; P < 0.006). Six patients (25%) had impaired glucose tolerance or overt diabetes mellitus (one patient). Insulin release was augmented but delayed in the Turner group, and the area under the insulin stimulation curve was correlated to body mass index (r = +0.54, P < 0.01). Thyroid antibodies were detected in nine patients (37.5%). On average, bone density of the forearm was only marginally reduced compared to the age-dependent normal range. All women were employed, while only one of the Turner women was married. As a group, the subjects expressed greater distress due to infertility compared to short stature.(ABSTRACT TRUNCATED AT 250 WORDS)

Type II pneumocytes secrete vitamin E together with surfactant lipids

Lung surfactant is exposed to strongly oxidizing conditions. We examined the hypothesis that in lung, lipophilic antioxidants are secreted together with surfactant to counteract the peroxidation of surfactant constituents. Lung lavage and the subfractions of the alveolar surfactant contain the lipophilic antioxidants vitamin E, vitamin A, and plasmalogens. The specific radioactivity of vitamin E isolated from serum, lung homogenate, lamellar bodies, and lung lavage increased linearly up to 3 h after intraperitoneal application of [3H]tocopherol. [3H]tocopherol was secreted in situ together with [14C]palmitic acid-labeled phospholipid in response to isoproterenol. Type II cells cultured in presence of [3H]tocopherol or of [3H]cholecalciferol and [14C]palmitic acid responded to isoproterenol by a time-dependent increase in secretion of [3H]tocopherol and of 14C-labeled phospholipids but not of [3H]cholecalciferol. The isoproterenol-stimulated secretion of [3H]tocopherol and of 14C-labeled phospholipids by type II cells is inhibited by surfactant protein A. We conclude that the alveolar surfactant contains lipophilic antioxidants as integral constituents. [3H]tocopherol seems to be secreted together with surfactant.

Pathobiochemical aspects of cytoskeleton components

This review summarizes pathobiochemical aspects of diseases, in which cytoskeletal components play a crucial role in pathogenesis. An attempt to classify the disorders on the basis of phenotypic changes that occur in microfilaments, intermediate filaments and microtubuli was unsuccessful. Three groups of disorders are presented: 1. cytoplasmic inclusions in specific diseases (merely descriptive); 2. diseases with genetic defects in cytoskeletal proteins (a chain of causality from defect to phenotype, in some cases with large gaps); 3. diseases with suspected involvement of cytoskeleton (hypothetical causal chain). Microfilaments are involved in certain pathogenetic processes on account of defects in their associated proteins; in Duchenne muscular dystrophy, dystrophin is defective, while the defective protein in Rett syndrome is synapsin. Defects in spectrin and membrane anchor proteins lead to disorders of the red cell membrane skeleton (congenital haemolytic anaemias). Intermediate filaments accumulate in some types of cytoplasmic inclusions, together with ubiquitin (Mallory bodies, desmin accumulation in some myopathies and others). A pathogenetic interpretation of this phenomenon is lacking. A genetic defect in certain types of keratin is the cause of epidermolysis bullosa. Interesting preliminary results are reviewed that reveal the crucial role of cytoskeletal components in a further group of diseases (intrahepatic cholestasis, Alzheimer disease, pemphigus). These disorders are currently under investigation, or are of theoretical interest with respect to the cytoskeleton. Specific reactions of cytoskeletal components in serum, which might be used diagnostically, have not been found.

The somatotropin-somatomedin axis in adult patients with Turner syndrome: measurement of stimulated GH, GH-BP, IGF-I, IGF-II and IGFBP-3 in 25 patients

So far, few studies have addressed the regulation of GH and GH-dependent growth factors in adult patients with Turner syndrome. We therefore studied a group of 25 genetically proven patients with Turner syndrome (age 20-50 years) and 10 control women (25-48 years). Turner patients were significantly shorter (148.7 +/- 1.1 cm vs. 169.1 +/- 2.3 cm; mean +/- SE; p < 0.0001) and more overweight [body mass index (BMI)] 25.6 +/- 1.3 vs. 21.4 +/- 0.6 in controls; p < 0.01). No significant differences were present when the integrated GH response to stimulation with arginine and the serum levels of GH-binding protein (GH-BP), IGF-I, IGF-II and binding protein 3 for IGFs (IGFBP-3) were compared between the two groups. However, more detailed analysis revealed significant abnormalities of the somatotropic axis in Turner patients. Pituitary GH secretion was negatively and serum GH-BP positively related to the degree of overweight in normal patients. In Turner patients, no such relationship was present, while IGF-II significantly increased with BMI. IGFBP-3 was positively related to adult height in normal women but not in Turner patients. While serum testosterone values did not affect any of the somatotropic parameters measured, there was a previously unreported, inverse relation between serum estradiol and GH-BP in controls but not in Turner patients. While adult patients with Turner syndrome do not display endocrine features of GH insufficiency, a detailed analysis reveals several abnormalities of the interrelation between anthropometric parameters, sex steroids and the pituitary-somatomedin axis.

Cholesterol blood levels in children: comparison of a Munich screening to worldwide studies from 1980 to 1990

Total cholesterol results of a screening of 134 Munich school children aged 6-11 years are described. In reviewing worldwide studies on blood lipids in children, in the last 10 years, I note a large variance in the so-called "normal" values, with mean levels of total cholesterol ranging from 148 to 214 mg%. Age-, sex-, and race-specific reference data for a population are needed. Only with these special data can one determine the point for intervention. With school health education programs, including medical screening examinations, the aim of primary prevention of coronary heart disease can be reached.

Studies on the formation of dipalmitoyl species of phosphatidylcholine and phosphatidylethanolamine in pulmonary type II cells

Endogenous content of and incorporation of labelled glycerol into alkenylacyl-, alkylacyl- and diacyl-glycerol, -glycerol-3-phosphocholine and -glycero-3-phosphoethanolamine of pulmonary type II cells were measured. On prolonged incubation of type II cells with labelled glycerol, the proportion of label incorporated into the diacyl subclass of these glycerolipids increased and the proportion of label incorporated into the ether lipids declined. Endogenous phosphatidylcholine (PtdCho) of type II cells contained 38.4% of the dipalmitoyl species, but endogenous phosphatidylethanolamine (PtdEtn) only 2.5%. In contrast, similar proportions of labelled glycerol were incorporated into dipalmitoyl-PtdCho and -PtdEtn after short-time incubation but, with prolonged incubation time the proportion of labelled dipalmitoyl-PtdCho increased from 11.3 to 18.8%, whereas that of dipalmitoyl-PtdEtn did not change significantly. Type II cell membranes were found to exhibit cofactor-independent and CoA-mediated transacylations of [1-14C]palmitoyl-lyso-PtdCho and -lyso-PtdEtn. The distribution of label among the palmitic acid-containing species of PtdCho and PtdEtn formed by both transacylation activities was determined. Cofactor-independent and CoA-mediated transacylation showed a strong selectivity for palmitate and arachidonate and a strong discrimination against oleate. The amount (nmol) of dipalmitoyl-PtdEtn formed by both transacylation activities after short-time incubation (2 min) decreased with prolonged incubation time (60 min). In contrast, the nmol of dipalmitoyl-PtdCho formed by cofactor-independent transacylation remains nearly the same after short-time and longer incubation. The nmol of dipalmitoyl-PtdCho formed by CoA-mediated transacylation increased strongly in the same time interval. Beside synthesis de novo via the CDP-choline pathway and reacylation of lyso-PtdCho with palmitoyl-CoA, the CoA-mediated transacylation of lyso-PtdCho may be an effective pathway for the formation of dipalmitoyl-PtdCho in pulmonary type II cells.

Species pattern of phosphatidic acid, diacylglycerol, CDP-diacylglycerol and phosphatidylglycerol synthesized de novo in rat liver mitochondria

Rat liver mitochondria were incubated with [3H]glycerol 3-phosphate, ATP, CTP and coenzyme A allowing acylatin of glycerophosphate with endogenous fatty acids and the further conversion of labelled phosphatidic acid (PA) to diacylglycerol (DG), CDP-diacylglycerol (CDP-DG) and phosphatidylglycerol (PG). In these glycerolipids, the distribution of label among the individual molecular species was found to be similar, with 16:0-18:1, 16:0-18:2 and 18:0-18:2/16:0-16:0 being the main species. It was concluded that mitochondrial enzymes involved in the de novo synthesis of these glycerolipids exhibited no acyl selectivity for their substrates. The pattern of molecular species of mitochondrial PA, DG and CDP-DG closely approached that of the same glycerolipids synthesized de novo in isolated rat liver microsomes.

Synthesis of phosphatidylcholine and phosphatidylglycerol in rat lung mitochondria

The mitochondrial fraction of adult rat lung contains choline phosphotransferase (EC 2.7.8.2) activity which can not be explained by microsomal contamination estimated on the basis of marker enzyme distribution. Mitochondrial (14C)glycerol-3-phosphate incorporation into PC (phosphatidylcholine) can be distinguished from the microsomal incorporation by different sensitivity to N-ethylmaleimide inhibition. The data indicate that rat lung mitochondria have the intrinsic capability to synthesize PC. Both synthesis of PC and PG (phosphatidylglycerol) are susceptible to isotonic tryptic attack against the cytoplasmic face of isolated rat lung mitochondria, suggesting the outer membrane location of crucial activities involved in the formation of these phospholipids. Rat liver mitochondria are different from rat lung mitochondria with respect to their capability to synthesize PC, their rate of (14C)glycerol-3-phosphate incorporation into PG as well as the submitochondrial site of PG formation.

The de novo synthesis of molecular species of phosphatidylinositol from endogenously labeled CDP diacylglycerol in alveolar macrophage microsomes

The de novo synthesis of molecular species of phosphatidylinositol (PI) from endogenously labeled CDP diacylglycerol (CDP-DG) and phosphatidic acid (PA), with [14C]-glycerol 3-phosphate, in microsomes of macrophages was studied using a recently developed HPLC technique. Endogenously labeled PA, CDP-DG, and PI were sequentially formed from labeled glycerol 3-phosphate through the addition of CoA, CTP, and then inositol into microsomes. The rate of formation of CDP-DG from endogenously labeled PA was low as compared with those of PA and PI. The low rate of CDP-DG synthesis suggests that it may be the rate-limiting step in the de novo synthesis of PI. Analysis of newly synthesized molecular species of PI by HPLC revealed that large proportions of radioactivity were associated with the 16:0-18:1, 16:0-18:2, 18:1-18:2, and 18:2-18:2 species, and a small amount, 2-3%, of radioactivity was associated with the 18:0-20:4 species. The profiles of newly synthesized PA and CDP-DG species were quite similar to those of PI species. This suggests that the enzymes involved in the formation of PI species from glycerol 3-phosphate show little specificity toward different molecular species of substrates. The results of the present study also suggest that free fatty acid composition in microsomes greatly affect the composition of the molecular species of PI synthesized through the de novo pathway, since the proportion of fatty acids utilized for the de novo synthesis of PI species was similar to that of free fatty acids in the microsomal membrane.

Species pattern of phosphatidylinositol from lung surfactant and a comparison of the species pattern of phosphatidylinositol and phosphatidylglycerol synthesized de novo in lung microsomal fractions

1. Phosphatidylinositol (PI) is a minor component of lung surfactant which may be able to replace the functionally important phosphatidylglycerol (PG) [Beppu, Clements & Goerke (1983) J. Appl. Physiol. 55, 496-502] without disturbing lung function. The dipalmitoyl species is one of the main species for both PI (14.4%) and PG (16.9%). Besides the C16:0--C16:0 species, the C16:0--C18:0, C16:0--C18:1, C16:0--C18:2 and C18:0--C18:1 species showed comparable proportions in the PG and PI fractions. These similarities of the species patterns and the acidic character of both phospholipids could explain why surfactant PG may be replaced by PI. 2. PI and PG were radiolabelled by incubation of microsomal fractions with [14C]glycerol 3-phosphate (Gro3P). For 11 out of 14 molecular species of PI and PG we measured comparable proportions of radioactivity. The radioactivity of these 11 species accounted together for more than 80% of the total. The addition of inositol to the incubation system decreased the incorporation in vitro of Gro3P into PG and CDP-DG (diacylglycerol) of lung microsomes (microsomal fractions), but did not change the distribution of radioactivity among the molecular species of PG. These results supported the idea that both acidic surfactant phospholipids may be synthesized de novo from a common CDP-DG pool in lung microsomes.

Phosphatidylethanolamine of lung surfactant: proportion and fatty acid patterns of the alkylacyl, alkenylacyl and diacyl subclasses

The phosphatidylethanolamine fraction isolated from lung surfactant consisted of 33% of the alkylacyl, 39% of the alkenylacyl and 25% of the diacyl subclass. Palmitic acid was the major fatty acid of the alkyl acyl and alkenylacyl subclasses. In diacylphosphatidylethanolamine, saturated and unsaturated fatty acids revealed a ratio of nearly 1.

Comparison of the HPLC-separated species patterns of phosphatidic acid, CDP-diacylglycerol and diacylglycerol synthesized de novo in rat liver microsomes (a new method)

The species pattern of phosphatidic acid was compared with that of CDP-diacylglycerol and diacylglycerol synthesized de novo by glycerol 3-phosphate acylation in a CoA ester-generating system in liver microsomes. The similarity of the species patterns of phosphatidic acid and CDP-diacylglycerol indicated that the CTP-phosphatidyl cytidylyltransferase showed no selectivity for individual species of its phosphatidic acid substrate. Since the species pattern of diacylglycerol deviated from that of phosphatidic acid, a slight acyl selectivity of the phosphatidic acid phosphohydrolase or a slight inhomogeneity of its substrate pool might be assumed. For the determination of the molecular species of CDP-diacylglycerol, a new method was developed. By incubation of CDP-diacylglycerol with oligonucleate 5'-nucleotidohydrolase (phosphodiesterase), phosphatidic acid was produced. The CDP-diacylglycerol-derived phosphatidic acid was methylated with diazomethane and then separated by reverse-phase HPLC in 15 molecular species.