Serenoa repens extract for benign prostate hyperplasia: a randomized controlled trial.

OBJECTIVE: To compare the effect of a Serenoa repens extract with placebo for symptoms of benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: In a double-blind placebo-controlled randomized trial between January 1999 and March 2000, 100 men with symptoms of BPH, aged < 80 years, with a maximum urinary flow rate of 5-15 mL/s for a voiding volume of 150 mL, were randomly and equally allocated to 320 mg S. repens extract or placebo (paraffin oil). The main outcome measures were the International Prostate Symptom Score (IPSS), peak urinary flow rate, and the Rosen International Index of Erectile Function (IIEF) questionnaire. RESULTS: There was no significant difference between the treatments over the 12 weeks of the study in the IPSS, peak urinary flow rate or for the IIEF questionnaire. CONCLUSIONS: During the trial all participants had some improvement in their symptoms of BPH but there was no significant beneficial effect of this S. repens extract over placebo in this 12-week trial.

The HIV-1 Vpr co-activator induces a conformational change in TFIIB.

Vpr is a HIV-1 virion-associated protein which plays a role in viral replication and in transcription and cell proliferation. We have previously reported that Vpr stimulates transcription of genes lacking a common DNA target sequence likely through its ability to interact with TFIIB. However, the molecular mechanism of the Vpr-mediated transcription remains to be precisely defined. In this in vitro study, we show that the binding site of Vpr in TFIIB overlaps the domain of TFIIB which is engaged in the intramolecular bridge between the N- and C-terminus of TFIIB, highly suggesting that binding of Vpr may induce a change in the conformation of TFIIB. Indeed, with a partial proteolysis assay using V8 protease, we demonstrate that Vpr has the ability to change the conformation of TFIIB. We investigated in this partial proteolysis assay a series of Vpr-mutated proteins previously defined for their transactivation properties. Our data show a correlation between the ability of Vpr-mutated proteins to stimulate transcription and their ability to induce a conformational change in TFIIB, indicating a functional relevance of the Vpr-TFIIB interaction.

Defective oligodendrocyte development and severe hypomyelination in PDGF-A knockout mice.

There is a class of oligodendrocyte progenitors, called O-2A progenitors, that is characterized by expression of platelet-derived growth factor &agr;-receptors (PDGFR(&agr;)). It is not known whether all oligodendrocytes are derived from these PDGFRalpha-progenitors or whether a subset(s) of oligodendrocytes develops from a different, PDGFR alpha-negative lineage(s). We investigated the relationship between PDGF and oligodendrogenesis by examining mice that lack either PDGF-A or PDGF-B. PDGF-A null mice had many fewer PDGFR alpha-progenitors than either wild-type or PDGF-B null mice, demonstrating that proliferation of these cells relies heavily (though not exclusively) on PDGF-AA homodimers. PDGF-A-deficient mice also had reduced numbers of oligodendrocytes and a dysmyelinating phenotype (tremor). Not all parts of the central nervous system (CNS) were equally affected in the knockout. For example, there were profound reductions in the numbers of PDGFR alpha-progenitors and oligodendrocytes in the spinal cord and cerebellum, but less severe reductions of both cell types in the medulla. This correlation suggests a close link between PDGFRalpha-progenitors and oligodendrogenesis in most or all parts of the CNS. We also provide evidence that myelin proteolipid protein (PLP/DM-20)-positive cells in the late embryonic brainstem are non-dividing cells, presumably immature oligodendrocytes, and not proliferating precursors.

DNA repair enzyme uracil DNA glycosylase is specifically incorporated into human immunodeficiency virus type 1 viral particles through a Vpr-independent mechanism.

The Vpr protein, encoded by the human immunodeficiency virus type 1 (HIV-1) genome, is one of the nonstructural proteins packaged in large amounts into viral particles. We have previously reported that Vpr associates with the DNA repair enzyme uracil DNA glycosylase (UDG). In this study, we extended these observations by investigating whether UDG is incorporated into virions and whether this incorporation requires the presence of Vpr. Our results, with highly purified viruses, show that UDG is efficiently incorporated either into wild-type virions or into Vpr-deficient HIV-1 virions, indicating that Vpr is not involved in UDG packaging. Using an in vitro protein-protein binding assay, we reveal a direct interaction between the precursor form of UDG and the viral integrase (IN). Finally, we demonstrate that IN-defective viruses fail to incorporate UDG, indicating that IN is required for packaging of UDG into virions.

A role for human immunodeficiency virus type 1 Vpr during infection of peripheral blood mononuclear cells.

Studies analysing human immunodeficiency virus type 1 replication in primary cells have demonstrated that Vpr, although dispensable, plays a role along with the matrix (MA) protein in allowing nuclear localization of viral preintegration complexes in non-dividing monocyte-derived macrophages (MDMs). In the current study, experimental infection conditions to analyse the role of Vpr, independently of MA, during infection of PHA/IL-2-stimulated peripheral blood mononuclear cells (PBMC) were designed. It was shown that the absence of Vpr results in a subtle effect on virus production in long-term infection. PCR analysis of the steps of virus retrotranscription during a single cycle of replication in stimulated PBMC revealed that the absence of Vpr alone correlates with an impairment in the nuclear localization of viral DNA. Our data indicate that Vpr is involved in the virus life-cycle during infection of dividing PBMC, presumably as it is during infection of MDMs.

Alveogenesis failure in PDGF-A-deficient mice is coupled to lack of distal spreading of alveolar smooth muscle cell progenitors during lung development.

PDGF-A(-/-) mice lack lung alveolar smooth muscle cells (SMC), exhibit reduced deposition of elastin fibres in the lung parenchyma, and develop lung emphysema due to complete failure of alveogenesis. We have mapped the expression of PDGF-A, PDGF receptor-alpha, tropoelastin, smooth muscle alpha-actin and desmin in developing lungs from wild type and PDGF-A(-/-) mice of pre- and postnatal ages in order to get insight into the mechanisms of PDGF-A-induced alveolar SMC formation and elastin deposition. PDGF-A was expressed by developing lung epithelium. Clusters of PDGF-Ralpha-positive (PDGF-Ralpha+) mesenchymal cells occurred at the distal epithelial branches until embryonic day (E) 15.5. Between E16.5 and E17.5, PDGF-Ralpha+ cells multiplied and spread to acquire positions as solitary cells in the terminal sac walls, where they remained until the onset of alveogenesis. In PDGF-A(-/-) lungs PDGF-Ralpha+ cells failed to multiply and spread and instead remained in prospective bronchiolar walls. Three phases of tropoelastin expression were seen in the developing lung, each phase characterized by a distinct pattern of expression. The third phase, tropoelastin expression by developing alveolar SMC in conjunction with alveogenesis, was specifically and completely absent in PDGF-A(-/-) lungs. We propose that lung PDGF-Ralpha+ cells are progenitors of the tropoelastin-positive alveolar SMC. We also propose that postnatal alveogenesis failure in PDGF-A(-/-) mice is due to a prenatal block in the distal spreading of PDGF-Ralpha+ cells along the tubular lung epithelium during the canalicular stage of lung development.

PDGF-A signaling is a critical event in lung alveolar myofibroblast development and alveogenesis.

A mouse platelet-derived growth factor A chain (PDGF-A) null allele is shown to be homozygous lethal, with two distinct restriction points, one prenatally before E10 and one postnatally. Postnatally surviving PDGF-A-deficient mice develop lung emphysema secondary to the failure of alveolar septation. This is apparently caused by the loss of alveolar myofibroblasts and associated elastin fiber deposits. PDGF alpha receptor-positive cells in the lung having the location of putative alveolar myofibroblast progenitors were specifically absent in PDGF-A null mutants. We conclude that PDGF-A is crucial for alveolar myofibroblast ontogeny. We have previously shown that PDGF-B is required in the ontogeny of kidney mesangial cells. The PDGFs therefore appear to regulate the generation of specific populations of myofibroblasts during mammalian development. The two PDGF null phenotypes also reveal analogous morphogenetic functions for myofibroblast-type cells in lung and kidney organogenesis.

Effects of exogenous wild-type p53 on a human lung carcinoma cell line with endogenous wild-type p53.

Several studies have shown that expression of exogenous wild-type p53 is detrimental to the growth of cell lines with absent or mutant p53. In this study, wild-type p53 cDNA expression plasmids were transfected into A549 lung carcinoma cells which had previously been shown by sequencing to contain wild-type p53. When a constitutively expressed wild-type p53 plasmid containing the neomycin resistance gene was transfected into these cells, no G418-resistant colonies contained the exogenous p53 cDNA even though the neomycin resistance gene was integrated. When cells were transfected with a dexamethasone-inducible wild-type p53 cDNA expression plasmid, induction of p53 expression resulted in a decreased growth rate and a decreased proportion of S-phase cells. Continuous treatment with dexamethasone resulted in continued p53 expression for 16 days, but beyond that time expression ceased and could not be reinduced. These data indicated that although the A549 cell line could proliferate in the presence of endogenous wild-type p53 there was a strong selection pressure against continued expression of additional exogenous wild-type p53.

Purification and properties of a novel insulin-like growth factor-II binding protein from transformed human fibroblasts.

We have purified an insulin-like growth factor (IGF) binding protein from culture medium conditioned by the SV40-transformed human fibroblast line AG 2804. This protein (TFBP), of apparent Mr = 34,000 on gel electrophoresis, binds IGF-II with an affinity constant of 3 x 10(11) liters/mol, 100-fold higher than its affinity for IGF-I. Amino-terminal sequencing indicated no structural relationship to any previously characterized IGF binding protein or receptor. Like a protein in cerebrospinal fluid with selective affinity for IGF-II, TFBP does not bind IGF-I lacking the amino-terminal tripeptide. In contrast with binding proteins produced by normal human fibroblasts, TFBP does not cross-react in radioimmunoassays for the plasma protein IGFBP-3 or the amniotic fluid protein IGFBP-1; however, after affinity labeling with IGF-II, it is immunoprecipitable by an anti-IGFBP-3 antiserum. The cerebrospinal fluid binding protein is not precipitable by this antiserum and appears smaller than TFBP. TFBP reacts with wheat germ agglutinin, but not with concanavalin A, or with the acid-labile subunit of the high molecular weight serum IGF binding protein complex. Furthermore, since RNA from transformed fibroblasts does not hybridize with an IGFBP-3 cDNA probe, TFBP is not derived from the IGFBP-3 gene. We conclude that, although TFBP appears to share an epitope with IGFBP-3, it is distinctly different from any previously described IGF binding protein.