Regulation of PDE5 expression in normal prostate, benign prostatic hyperplasia, and adenocarcinoma

BACKGROUND

Type 5 phosphodiesterase (PDE5) expression in the normal and pathological prostate is controversial.

OBJECTIVES

This study aimed at identifying the cell type/s, if any, expressing PDE5 in human healthy or pathological prostate sections in order to further validate the rationale of PDE5 inhibitor (PDE5i) treatment of benign prostatic hyperplasia (BPH) and their safety in the treatment of erectile dysfunction following prostate cancer (PCa) surgery.

MATERIALS AND METHODS

By immunohistochemical analysis, we studied PDE5 expression in tissue microarrays containing sections obtained from healthy, BPH, and PCa samples.

RESULTS

Our results showed that PDE5 is barely expressed in the epithelial or stromal compartment of normal human prostates, but it is highly expressed in the stromal compartment of BPH sections. We also found that a low but significant number of PCa samples (22%) expressed PDE5 in the epithelial cancer cells but not in stromal cells and that such expression was not correlated with the tumor aggressiveness, according to their Gleason score.

DISCUSSION AND CONCLUSION

PDE5 overexpression in the stromal compartment of BPH samples supports the rationale of PDE5 as a target in lower urinary tract symptoms of BPH. PDE5 expression in a significant percentage of PCa samples but the lack of correlation with the Gleason score suggests that this enzyme is not correlated with tumor aggressiveness; however, a role of PDE5 in the minimal residual disease of PCa cannot be excluded.

Constitutive expression of suppressor of cytokine signalling-3 in skeletal muscle leads to reduced mobility and overweight in mice

AIMS/HYPOTHESIS

Due to their ability to regulate various signalling pathways (cytokines, hormones, growth factors), the suppressor of cytokine signalling (SOCS) proteins are thought to be promising therapeutic targets for metabolic and inflammatory disorders. Hence, their role in vivo has to be precisely determined.

METHODS

We generated transgenic mice constitutively producing SOCS-3 in skeletal muscle to define whether the sole abundance of SOCS-3 is sufficient to induce metabolic disorders and whether SOCS-3 is implicated in physiological roles distinct from metabolism.

RESULTS

We demonstrate here that chronic expression of SOCS-3 in skeletal muscle leads to overweight in mice and worsening of high-fat diet-induced systemic insulin resistance. Counter-intuitively, insulin sensitivity in muscle of transgenic mice appears to be unaltered. However, following constitutive SOCS-3 production, several genes had deregulated expression, among them other members of the SOCS family. This could maintain the insulin signal into skeletal muscle. Interestingly, we found that SOCS-3 interacts with calcineurin, which has been implicated in muscle contractility. In Socs-3 transgenic muscle, this leads to delocalisation of calcineurin to the fibre periphery. Relevant to this finding, Socs-3 transgenic animals had dilatation of the sarcoplasmic reticulum associated with swollen mitochondria and decreased voluntary activity.

CONCLUSIONS/INTERPRETATION

Our results show that constitutive SOCS-3 production in skeletal muscle is not in itself sufficient to induce the establishment of metabolic disorders such as diabetes. In contrast, we reveal a novel role of SOCS-3, which appears to be important for muscle integrity and locomotor activity.

Structural changes induced in proteins by therapeutic ultrasounds

The structural effect induced by therapeutic ultrasound on proteins in aqueous solution has been investigated with FTIR spectroscopy, UV-VIS spectroscopy, circular dichroism and light scattering. Six proteins (cytochrome, lysozyme, myoglobin, bovine serum albumin, trypsinogen, and alpha-chymotrypsinogen A) with different molecular weight and secondary structure have been studied. The experiment has been performed using an ultrasound source at resonant frequency of 1 MHz and sonication times of 10, 20, 30, 40, 50, and 60 min. A different behaviour of proteins under sonication depends on the dominant secondary structure type (alpha-helix or beta-sheets) and on the grade of the ordered structure. The results suggest that the free radicals, produced by water sonolysis, have an important role in the changes of structural order.

An uncommon large deletion in the androgen-receptor gene in a XY female with complete androgen insensitivity syndrome

Androgen insensitivity is a disorder characterized by an abnormal male sexual development, in which the androgen action is impaired due to structural defects in the androgen receptor gene. We report a case of a 46,XY subject with female phenotype (normal breast and external genitalia) lacking sexual hair, affected with primary amenorrhea. In this patient, we found a deletion of a large region of the androgen receptor gene encoding the steroid-binding domain of the protein, causing a complete inability to bind the androgens. This uncommon molecular defect impaired the expression of androgen-dependent genes inducing the female phenotype.

Molecular biology tools for dissecting sexual behavior

The tools of molecular biology have just begun to demonstrate the role of genes in controlling sexual behavior and how hormones can influence sexual and reproductive motivation by controlling gene expression. In this review article the use of the new term "molecular sexology" is proposed to indicate the growing evidence that molecular biology techniques can be a useful tool not only to understand the genetic bases of the animal (and soon human) sexual behavior, but also in order to provide the rationale of the use of advanced therapeutic approaches, such as gene transfer, to the symptoms and diseases of sexuality.

Novel point mutation in the splice donor site of exon-intron junction 6 of the androgen receptor gene in a patient with partial androgen insensitivity syndrome

Androgen receptor (AR) gene mutations have been shown to cause androgen insensitivity syndrome with altered sexual differentiation in XY individuals, ranging from a partial insensitivity with male phenotype and azoospermia to a complete insensitivity with female phenotype and the absence of pubic and axillary sexual hair after puberty. In this study we present an 11-yr-old XY girl, with clinical manifestations peculiar for impaired androgen biological action, including female phenotype, blind-ending vagina, small degree of posterior labial fusion, and absence of uterus, fallopian tubes, and ovaries. At the time of the diagnosis the patient had a FSH/LH ratio according to the puberal stage, undetectable 17beta-estradiol, and high levels of testosterone (80.1 ng/mL). After bilateral gonadectomy, performed at the age of 11 yr, histological examination showed small embryonic seminiferous tubules containing prevalently Sertoli cells and occasional spermatogonia together with abundant fibrous tissue. Molecular study of the patient showed a guanine to thymine transversion in position +5 of the donor splice site in the junction between exon 6 and intron 6 of the AR gene. The result of RT-PCR amplification of the AR messenger ribonucleic acid from cultured genital skin fibroblasts of the patient suggests that splicing is defective, and intron 6 is retained in most of the receptor messenger ribonucleic acid molecules. We show by immunoblotting that most of the expressed protein lacks part of the C-terminal hormone-binding domain, and a small amount of normal receptor is observed. This is probably responsible for the reduced binding capacity in genital skin fibroblasts of the patient. The molecular basis of the alteration in this case is a novel, uncommon mutation, leading to a phenotype indicative of a partial androgen insensitivity syndrome, Quigley's grade 5.

An SRY-negative XX male with Huriez syndrome

This report studies a 42-year-old 46,XX patient affected by palmoplantar keratoderma. clinically classified as Huriez syndrome. The patient showed a male phenotype with apparently normal male features including testicular development. Cytogenetic and chromosomal painting analysis excluded the presence of translocation of the Y chromosome. PCR analysis of genomic DNA failed to detect the presence of the testis-determining gene, SRY. The presence of other Y-chromosome genes, known to be involved in testicular maturation and spermatogenesis, has also been analyzed. The data suggest that the sex reversal in this 46,XX male patient is due to a defect on a yet unidentified autosomal or X-linked sex-determining gene. The relationship between the sex reversion and the presence of sclerotylosis is discussed.

CD36 antisense expression in 3T3-F442A preadipocytes

An adipocyte membrane glycoprotein, FAT, homologous to CD36, has been implicated in the binding/transport of long-chain fatty acids. FAT/CD36 was identified by reaction with reactive long chain fatty acids derivatives under conditions where they inhibited FA uptake. Expression of CD36 in fibroblasts lacking the protein led to induction of a saturable high affinity, phloretin-sensitive component of oleate uptake. In this report, we have examined the effects of FAT/CD36 antisense expression in 3T3-F442A preadipocyte cells, on FA uptake and cell differentiation. Cells were transfected with pSG5-TAF vector obtained by insertion of antisense coding sequence of FAT/CD36 into the BamH 1 site of pSG5. Four clones were selected based on expression of antisense CD36 mRNA. Levels of CD36 protein were determined by flow cytometry and correlated with rates of oleate uptake. Three clones, TAF13, TAF25, and TAF38 exhibited low CD36 expression and one clone TAF 18 had expression comparable to that of F442A control cells. FA uptake rates in clones TAF13, TAF25 and TAF38 were lower than those observed in TAF18. At confluence, adipocyte differentiation could be promoted by addition of insulin and triiodothyronine only in TAF18 cells but not in TAF13, TAF25 or TAF38. Addition of fatty acids to clones TAF13, TAF25 and TAF38 lead to an induction of CD36 expression, an enhancement of FA uptake and better cell differentiation. The data support a role of CD36 in the membrane uptake of long chain FA. CD36 expression and FA uptake appear to be closely linked to preadipocyte differentiation.

Analysis of Yq microdeletions in infertile males by PCR and DNA hybridization techniques

Defects in spermatogenesis have been found associated with deletions of different portions of Y chromosome long arm (Yq), suggesting the presence of the azoospermia factor in the control of spermatogenesis. We studied 67 men with idiopathic azoospermia and severe oligozoospermia, cytogenetically normal, for the presence of microdeletions on Yq chromosome. By using polymerase chain reaction (PCR) and Southern blotting techniques we analysed the AZFa, AZFb and AZFc loci on Yq, where deletions have been associated with defects in spermatogenesis. Deletions of a portion of the Y chromosome were detected in five patients. Four of these patients shared deletions in distal Yq11 interval 6, including the DAZ gene, while one patient lacked loci in the proximal Yq11. Testicular histology of two patients bearing distal Yq11 deletions showed two different spermatogenic defects including Sertoli cell-only (SCO) syndrome and maturation arrest, while the patient with microdeletions in the proximal Yq11 showed a SCO phenotype.

Medicare's new capitation method

The method used to determine capitation rates for Medicare risk-bearing health plans changed on January 1, 1998. The new approach establishes a minimum rate that is substantially higher than the amounts Medicare previously paid in most of the nation's counties, reduces the volatility in the rates, and guarantees all participating health plans at least a 2 percent annual rate increase for the next several years. It is hoped that the methodological improvements will motivate more health plans to become Medicare contractors.

Identification of a promoter region generating Sry circular transcripts both in germ cells from male adult mice and in male mouse embryonal gonads

The mouse testis determining gene Sry is expressed in somatic cells of the differentiating male gonad as a linear transcript, encoding a transcription factor containing an HMG box. In the adult mouse testis, Sry expression occurs in meiotic and postmeiotic germ cells. The mouse genomic Sry locus is characterized by two arms of a large inverted repeat, flanking a unique region that, between an acceptor and a donor splice site, contains a single exon encoding the Sry protein. In germ cells from the adult mouse testis, Sry RNA is a circular molecule, which is generated by an inverted splicing event that utilizes the above-mentioned splice sites. Thus, a circular exon is spliced out starting from a large linear RNA precursor containing both arms of the inverted repeat, which pair and generate a large stem-loop structure. Using reverse transcription-polymerase chain reaction and an RNase protection assay, we have now mapped the 5' end of this precursor RNA in the 5' arm of the inverted repeat. Gel mobility shift assay and in vitro transcription with nuclear extracts from adult germ cells further confirm that a region immediately 5' upstream of two transcriptional initiation sites of the precursor RNA contains a promoter sequence in which two consensus Sry binding sequences are specifically recognized by nuclear factors present in adult germ cells but not in Sertoli cells. We also show that the linear precursor of the Sry circular transcript and its splicing product are specifically expressed not only in adult germ cells but also in male embryonal gonads between 11.5 and 13.5 days postcoitum, immediately after the expression of the linear transcript starting from the unique region.

Regulation of FAT/CD36 gene expression: further evidence in support of a role of the protein in fatty acid binding/transport

Much biochemical evidence has implicated rat adipocyte CD36 (FAT) in membrane binding and transport of long-chain fatty acids (FA). Expression of the mRNA favored tissues with active FA metabolism and was upregulated in vivo with diabetes and with high fat feeding. In culture, CD36 mRNA was a strong marker of preadipocyte differentiation and was modulated by the same factors effective on mRNAs coding for other proteins involved in FA metabolism. In preadipocytes, long-chain FA or 2-bromopalmitate but not short-chain FA strongly induced CD36 mRNA within 8 h to an optimum within 24 h. Removal of the FA resulted in a decay of CD36 mRNA with a half life of about 12 h. In differentiated adipocytes, levels of CD36 mRNA were downregulated by the 3': 5'-cyclic adenosine monophosphate, cAMP, analog, 8-(4-chlorophenylthio) adenosine, 8-CPT, at concentrations of 1-100 microM. The effect, observed within 6 h, was optimal after 18 h and independent of the action of 8-CPT to mobilize FA. Regulation of CD36 expression by factors effective on expression of other proteins implicated in FA metabolism is consistent with its role in membrane FA transport.

Expression of the CD36 homolog (FAT) in fibroblast cells: effects on fatty acid transport

An adipocyte membrane glycoprotein, (FAT), homologous to human CD36, has been previously implicated in the binding/transport of long-chain fatty acids. It bound reactive derivatives of long-chain fatty acids and binding was specific and associated with significant inhibition of fatty acid uptake. Tissue distribution of the protein and regulation of its expression were also consistent with its postulated role. In this report, we have examined the effects of FAT expression on rates and properties of fatty acid uptake by Ob17PY fibroblasts lacking the protein. Three clones (P21, P22, and P25) were selected based on FAT mRNA and protein levels. Cell surface labeling could be demonstrated with the anti-CD36 antibody FITC-OKM5. In line with this, the major fraction of immunoreactive FAT was associated with the plasma membrane fraction. Assays of oleate and/or palmitate uptake demonstrated higher rates in the three FAT-expressing clones, compared to cells transfected with the empty vector. Clone P21, which had the highest protein levels on Western blots, exhibited the largest increase in transport rates. Fatty acid uptake in FAT-expressing P21 cells reflected two components, a phloretin-sensitive high-affinity saturable component with a Km of 0.004 microM and a basal phloretin-insensitive component that was a linear function of unbound fatty acid. P21 cells incorporated more exogenous fatty acid into phospholipids, indicating that binding of fatty acids was followed by their transfer into the cell and that both processes were increased by FAT expression. The data support the interpretation that FAT/CD36 functions as a high-affinity membrane receptor/transporter for long-chain fatty acids.

[Invasive aspergillosis in the hematologic patient: the usefulness of computed tomographic and high-resolution computed tomographic studies]

Invasive aspergillosis is an emerging cause of death in hematologic patients. Several patterns of lung involvement are described: acute tracheobronchitis, bronchopneumonia, pleural aspergillosis and angioinvasive aspergillosis. The latter pattern is the most common one; it is characterized by different signs, some of which, supported by clinical data, are quite suggestive for fungal etiology. Particularly, nodules and/or wedge-shaped lesions with a ground-glass halo are a useful early feature, best detected by HRCT. Early therapy with amphotericin B may improve survival chances. Therefore, in neutropenia patients we decided, when possible, to perform high-resolution computed tomography (HRCT) as soon as fever appears. This was feasible in 8 of 32 patients with invasive aspergillosis examined with HRCT. Immediate treatment with amphotericin B in one such patient showing a nodule with the halo sign allowed the lesion to completely disappear. The authors describe the frequency of different radiologic signs in 32 patients, as observed in 54 HRCT exams; the results are compared with those obtained with conventional CT and chest X-ray. Compared to chest X-ray, CT detects more lesions and is more sensitive to small pneumothorax and minimal pleural effusion or thickening. HRCT is more suitable to detect initial cavitation and thin ground-glass haloes.

The same sequence mediates activation of the human urokinase promoter by cAMP in mouse Sertoli cells and by SV40 large T antigen in COS cells

Cell-specific activation by follicle-stimulating hormone and its intracellular mediator, cAMP, of the human urokinase promoter in mouse Sertoli cells requires overlapping purine-rich and GC-rich sequences between -54 and -42 from the transcriptional start site. We have previously shown that binding of unidentified nuclear factors to these sequences is induced by cAMP stimulation, and that sequences from the enhancerless SV40 replication origin can interfere with the binding, whereas consensus Sp1 binding sites are ineffective. We now show that sequences within the SV40 origin able to compete for the formation of cAMP-induced DNA-protein complexes in Sertoli cell nuclear extracts are binding sites for the SV40 large T antigen. Large T antigen expressed in COS cells binds the cAMP-responsive sequences of the human urokinase gene and transactivates the proximal promoter, thus mimicking the effect of nuclear factors induced by cAMP in Sertoli cells. We show that Egr-1 is one of the factors present in cAMP-induced DNA-protein complexes formed between the human urokinase promoter and Sertoli cell nuclear extracts. However, Egr-1 levels are similar in unstimulated and cAMP-treated Sertoli cells, suggesting that this factor interacts with a different GC-box binding factor, that we have previously shown to be strongly induced by cAMP treatment of Sertoli cells. We propose that SV40 large T antigen in COS cells can mimick the action of heterodimers formed in cAMP stimulated Sertoli cells between Egr-1 and a cell specific cAMP-induced GC-box binding factor.

Induction of the acyl-coenzyme A synthetase gene by fibrates and fatty acids is mediated by a peroxisome proliferator response element in the C promoter

The long-chain acyl-coenzyme A synthetase (ACS) gene gives rise to three transcripts containing different first exons preceded by specific regulatory regions A, B, and C. Exon-specific oligonucleotide hybridization indicated that only A-ACS mRNA is expressed in rat liver. Fibrate administration induced liver C-ACS strongly and A-ACS mRNA to a lesser extent. B-ACS mRNA remained undetectable. In primary rat hepatocytes and Fa-32 hepatoma cells C-ACS mRNA increased after treatment with fenofibric acid, alpha-bromopalmitate, tetradecylthioacetic acid, or alpha-linolenic acid. Nuclear run-on experiments indicated that fenofibric acid and alpha-bromopalmitate act at the transcriptional level. Transient transfections showed a 3.4-, 2.3-, and 2.2-fold induction of C-ACS promoter activity after fenofibric acid, alpha-bromopalmitate, and tetradecylthioacetic acid, respectively. Unilateral deletion and site-directed mutagenesis identified a peroxisome proliferator activator receptor (PPAR)-responsive element (PPRE) mediating the responsiveness to fibrates and fatty acids. This ACS PPRE contains three imperfect half sites spaced by 1 and 3 oligonucleotides and binds PPAR.retinoid X receptor heterodimers in gel retardation assays. In conclusion, the regulation of C-ACS mRNA expression by fibrates and fatty acids is mediated by PPAR.retinoid X receptor heterodimers interacting through a PPRE in the C-ACS promoters. PPAR therefore occupies a key position in the transcriptional control of a pivotal enzyme controlling the channeling of fatty acids into various metabolic pathways.

Fatty acids and retinoids act synergistically on adipose cell differentiation

Fatty acids and retinoids have been recently reported to act as positive effectors of adipose cell differentiation. Treatment of Ob1771 preadipose cells with selective agonists of retinoic acid receptors (RARs) in the presence of alpha-bromopalmitate, a non-metabolized fatty acid, led to a potent synergy in regard to the differentiation process, as assayed by the activity of glycerol-3-phosphate dehydrogenase. The most potent synergy was observed with compound CD 367, a potent agonist of RARs as well as with compound Am 580, a specific agonist of RAR alpha. Northern blot analysis of poly(A)+ mRNA from cells treated with compound CD 367, alpha-bromopalmitate, or a combination of both agonists, did not show a dramatic effect, if any, on the expression of RAR alpha, RAR gamma, RXR alpha and RXR beta genes. The results are discussed in light of the formation of heterodimers between RARs, RXRs and members of the family of peroxisome proliferator-activated receptors (PPARs).

Expression cloning in K+ transport defective yeast and distribution of HBP1, a new putative HMG transcriptional regulator

The rat HBP1 cDNA was cloned by its capacity to suppress the potassium transport-defective phenotype of mutant Saccharomyces cerevisiae cells. HBP1 cDNA encodes a 513 amino acids protein which, unexpectedly, does not share any homology with K+ transporters or K+ channels. However, a search in protein databases reveals that HBP1 contains a putative DNA-binding domain called HMG-box. Northern blot analysis shows that HBP1 is expressed in a variety of tissues and that in adipocyte and myogenic cell lines, its expression is directly related to differentiation. Taken together, the results suggest that the rat HBP1 is a new member of the HMG class of transcriptional regulators involved in cell differentiation pathways.

Retinoids are positive effectors of adipose cell differentiation

Retinoids, especially all-trans retinoic acid (t-RA), have been reported in the last decade to inhibit the differentiation of preadipose cells. In those studies, however, the concentrations of t-RA were supraphysiological (0.1-10 microM range). In contrast we show that, when present at concentrations below or close to the Kd values of retinoic acid receptors, retinoids behave as potent adipogenic hormones (1 pM to 10 nM range). As shown by the use of specific ligands for each RAR subtype, these positive effects on adipose differentiation involve in particular the RAR alpha subtype, and have been observed in Ob17 cells exposed to serum-supplemented or serum-free medium, and in rat preadipocytes exposed to serum-free medium. Among the two classes of retinoid acid receptors (RARs) and retinoid X receptors (RXRs), RAR alpha, RAR gamma, RXR alpha and RXR beta mRNAs could be detected in growing adipoblasts and were found to be increased in committed preadipocytes and differentiated cells upon retinoid treatment. Like other adipogenic hormones, retinoids were only effective in the terminal differentiation process leading from preadipocytes to adipocytes.

Hormonal regulation of adipose differentiation

Adipose differentiation is a multistep process with the following sequence: adipoblasts --> preadipocytes --> adipocytes. Adipogenic agents are only involved in the terminal differentiation of preadipocytes to adipocytes by means of circulating hormones (growth hormone, glucocorticoids, or triiodothyronine) and locally produced hormones (prostacyclin). Fatty acids also behave as hormones and act as transcriptional regulators of lipid-related genes. Once differentiated, adipocytes become secretory cells able to synthetize and release an impressive number of peptide and nonpeptide compounds, suggesting a potential link between excess of adipose tissue mass and various physiopathphysiologic consequences.

Acyl-CoA synthetase mRNA expression is controlled by fibric-acid derivatives, feeding and liver proliferation

Several enzymes of the beta-oxidation pathway have been shown to be induced after stimulation with peroxisomal proliferators, including several hypolipidemic drugs. We investigated the regulation of the long-chain-acyl-CoA synthetase (ACS) gene in the liver. Fenofibrate, a hypolipidemic drug and potent peroxisomal proliferator, induced ACS gene expression in several tissues. In liver, large increases in ACS mRNA levels and ACS activity were observed after fenofibrate administration. Adipose tissue ACS mRNA levels and ACS activity were also stimulated upon fibrate treatment but to a lesser extent in comparison with liver ACS mRNA. Kidney ACS mRNA was only weakly induced, except for the highest dose and the longest treatment period, where a strong induction was observed. In contrast to these tissues, heart ACS mRNA and ACS activity remained almost unchanged after fenofibrate treatment. These effects of fenofibrate could be reproduced by other fibrates such as clofibrate. In addition, it is demonstrated that both nutritional composition and liver proliferation trigger ACS gene expression in liver. Consequently, these data suggest that ACS is a highly regulated enzyme with a potentially important control function in lipid metabolism.

Identification of 3',5'-cyclic adenosine monophosphate-inducible nuclear factors binding to the human urokinase promoter in mouse Sertoli cells

Transcription factors which recognize both the SV40 promoter and the proximal promoter region of the human urokinase-type plasminogen activator (h-uPA) gene are present in nuclear extracts from primary cultures of mouse Sertoli cells; prolonged (more than 12 h) (Bu)2cAMP stimulation of Sertoli cells induces the formation of different specific DNA-protein complexes. A discrete region in the h-uPA promoter, between -54 and -42, is essential for the formation of the cAMP-induced DNA-protein complexes. Mutation of the sequence between -54 and -42 abolishes the response to cAMP of the proximal h-uPA promoter in Sertoli cells. A protein, recognizing a sequence centered around the GC-box present between -48 and -43, is detected by Southwestern analysis, and it is clearly induced by (Bu)2cAMP stimulation. Interaction between this protein and a second factor, recognizing a purine-rich sequence between -53 and -46, partially overlapping the GC-box, is needed for the formation of the cAMP-induced DNA-protein complexes. A preformed complex between the cAMP-induced GC-box-binding factor and the second factor can be detected using nondenaturing conditions during Southwestern analysis.

Direct evidence that the mouse sex-determining gene Sry is expressed in the somatic cells of male fetal gonads and in the germ cell line in the adult testis

Reverse transcriptase polymerase chain reaction (RT-PCR) analysis shows that Sry mRNA is expressed in male fetal urogenital ridges from 12.5 day p.c. embryos, but not in enriched populations of primordial germ cells from the same embryos, indicating that Sry is expressed in the somatic cells of the embryonal gonad at the time of testis determination. We also show that, in the adult male mouse testis, Sry mRNA is expressed at high levels in meiotic and postmeiotic germ cells and, at much lower levels, also in Sertoli cells. Treatment with cyclic adenosine monophosphate (cAMP) analogs of cultured Sertoli cells from postnatal testis completely abolishes Sry mRNA expression.

Cloning of alpha 2 chain of type VI collagen and expression during mouse development

We have previously described the molecular cloning of a cDNA probe which detects a 6 kb mRNA termed pOb24. pOb24 mRNA appeared to be a marker of the preadipose state both in vitro and in vivo. A pOb24 genomic fragment was isolated and used to screen cDNA libraries in order to isolate the full-length pOb24 cDNA and to identify the corresponding protein. The screening yielded a new cDNA clone which detected a 3.7 kb mRNA species in addition to the 6 kb mRNA species. Sequences at the 3' end of the 6 kb and 3.7 kb mRNAs indicate that both mRNAs are generated from the same gene through the use of two different polyadenylation sites. The protein encoded by the 3.7 kb mRNA appeared to be homologous to the human alpha 2 chain of type VI collagen (A2COL6). The expression of the A2COL6 gene was not confined to adipose tissue; mRNA species can be detected in ovaries, adrenal glands and lungs but not in liver and skeletal muscle. The expression appeared specific for initial phase(s) of cell differentiation since it is parallel to that of the MyoD1 gene during muscle embryogenesis in vivo. In the myogenic C2C12 cell line, the A2COL6 gene exhibited the same regulation as MyoD1 and myogenin genes. These results indicate that A2COL6 gene expression is a marker of the preadipose state, but may also be a marker of other differentiation programmes such as that of muscle.

Latest Medicare benefit: FQHC (Federally Qualified Health Center) services

The Federally Qualified Health Center (FQHC) service benefit has been effective since Oct. 1, 1991, but the governing "interim final" regulations were not issued until June 12, 1992. Paul Grimaldi, PhD, details the requirements that must be met in order for a clinic or center to qualify for FQHC reimbursement.

Follicle-stimulating hormone induction of steel factor (SLF) mRNA in mouse Sertoli cells and stimulation of DNA synthesis in spermatogonia by soluble SLF

Follicle-stimulating hormone (FSH) and its intracellular mediator, cAMP, increase the mRNA levels for the Steel factor (SLF, the c-kit ligand) in cultured primary mouse Sertoli cells. The inductive effect of cAMP is more evident in cultures from 13-day-old animals than in cultures from 18-day-old animals. Analysis through the polymerase chain reaction (PCR) indicates that (Bu)2cAMP or FSH treatment increases the levels of the mRNAs for both the potentially soluble form and the transmembrane form of SLF in cultured Sertoli cells. The ratio between mRNAs encoding the potentially soluble form and the transmembrane form of SLF increases during postnatal testis development, and it is higher in cultured Sertoli cells with respect to total testis, suggesting that, under the in vitro conditions, SLF could be produced by Sertoli cells mainly as a soluble factor. Soluble recombinant SLF stimulates, in a dose-dependent fashion, thymidine incorporation in cultures of isolated germ cell populations enriched in the mitotic stages (spermatogonia), independently of the presence of serum, whereas cAMP analogs have no effect. Autoradiographic analysis shows that SLF selectively stimulates DNA synthesis in type A spermatogonia.

Changes in Medicare capital PPS rates and rules

Author Grimaldi discusses recent changes in Medicare's capital prospective payment system (PPS) regulations, published in the Federal Register, September 1992, as well as major changes in operating cost guidelines that affect capital payments. Policy interpretations that the Health Care Financing Administration (HCFA) has issued in the past year are reviewed, and changes made to the Medicare cost report in order to accommodate capital PPS are summarized schedule by schedule.

Cellular and molecular aspects of adipose tissue development

Both in animals and humans, before or after birth, angiogenesis appears to be closely coordinated in time and space with the formation of fat cell clusters. Monobutyrin, a novel fat-specific angiogenesis factor, may play a role in this process. The potential to acquire new fat cells appears to be permanent throughout life in both animals and humans, as revealed by in vitro experiments. Considerable evidence now supports the view that BAT and WAT are distinct organs; in addition, the existence of distinct BAT precursor cells is demonstrated by their unique ability to express the UCP gene. In bovine and ovine, the transformation of BAT into WAT is strongly suggested by the rapid disappearance after birth of UCP from the various BAT depots. Despite the initial cell heterogeneity of the stromal-vascular fraction, cultured stromal-vascular cells of adipose tissue are adipose precursor cells that show varying capacities for replication and differentiation, according to age and fat depot. Studies of adipose cell differentiation in vitro correspond to the sequence: adipoblast (unipotential cells)----commitment preadipose cell (preadipocyte)----terminal differentiation immature adipose cell----terminal differentiation mature adipose cell (adipocyte). Cell commitment is triggered by growth arrest and characterized by the expression of early markers (A2COL6/pOb24; clone 5; LPL), whereas only terminal differentiation of preadipocytes requires the presence of various hormones. Multiple signaling pathways have been characterized and shown to cooperate in the process of terminal differentiation. The concept that adipose cells behave as secretory cells is now emerging from in vitro data, since secretion of various proteins (LPL, adipsin, CETP) and important metabolites (fatty acids, monobutyrin, androgens, estrogens, prostaglandins) takes place both constitutively and upon hormonal stimulation. This suggests that adipose tissue participates more directly than previously thought in metabolic activities and energy balance.

Molecular dynamics study of the conformational behavior of a representative elastin building block: Boc-Gly-Val-Gly-Gly-Leu-OMe

The conformational behavior of the synthetic peptide, Boc-Gly-Val-Gly-Gly-Leu-OMe, containing the X-Gly-Gly and Gly-Gly-X (X = Val or Leu) repeating sequences and constituting a fragment of elastin was investigated by molecular mechanics and molecular dynamics (MD) simulation. The results suggest that, irrespective of the approximations used, the molecule shows a manifold of low energy conformations characterized by gamma-turns and type II beta-turns. Furthermore, MD simulations point out a conformational floppiness due to very low barriers between different conformations. Experimental CD measurements in a virtually apolar medium (dioxane--epsilon = 2.209), which better mimics the vacuum conditions of the simulation, support the theoretical results. The general emerging picture, indicating the molecule as characterized by a combination of flexibility with conformational preferences, is in agreement with previous experimental findings and enriches of new aspects the description of the microscopic behavior of this molecule suggesting more detailed interpretation of previous data.