Sufficient Volume Ablation with Photoselective Vaporization of the Prostate Delivers 5-Year Durability and Improves Symptom Relief for Larger Prostates.

OBJECTIVES: To assess the long-term durability of photoselective vaporization of the prostate (PVP) for symptomatic benign prostatic enlargement (BPE) or benign prostatic obstruction (BPO) and treatment efficacy for large BPE. METHODS: Four hundred fifty-seven patients with symptomatic BPE underwent PVP between January 2006 and April 2009. Efficacy was evaluated with the International Prostate Symptoms Score (IPSS), Quality of Life (QOL) score, urinary peak flow (Qmax), postvoid residual volume (PVR), and prostate volume. Parameters were checked preoperatively, and at 1, 3, and 5 years postoperatively. One hundred fifty-three patients completed 5-year follow-up. To assess treatment effects, patients were divided into two groups according to the preoperative prostate volume: group A (<60 mL, n=104) and group B (>60 mL, n=49). RESULTS: Mean IPSS, QOL score, Qmax, and PVR improved significantly and were maintained for 5 years with no significant differences; at year 1, prostate volume had decreased significantly from 54.0 mL to 30.6 mL (43% of volume ablation) and remained at that level until year 5. Investigations according to prostate size demonstrate that IPSS and QOL scores in group B remained at significantly lower levels, and Qmax in group B improved more than in group A. 1.1% of patients needed transurethral resection of the prostate due to BPO recurrence. CONCLUSIONS: PVP is effective and provides durable results for 5 years, with sustained symptom relief and improved urinary flow rate, as well as a 43% volume reduction of prostate volume. Our data indicate PVP is more efficacious for larger prostates under sufficient volume ablation.

The Arabidopsis FLAKY POLLEN1 gene encodes a 3-hydroxy-3-methylglutaryl-coenzyme A synthase required for development of tapetum-specific organelles and fertility of pollen grains.

The pollen coat is a surface component of pollen grains required for fertilization. To study how the pollen coat is produced, we identified and characterized a recessive and conditional male-sterile Arabidopsis mutant, flaky pollen1-1 (fkp1-1), whose pollen grains lack functional pollen coats. FKP1 is a single-copy gene in the Arabidopsis genome and encodes 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMG-CoA synthase), an enzyme of the mevalonate (MVA) pathway involved in biosynthesis of isoprenoids such as sterols. We found that fkp1-1 possesses a T-DNA insertion 550 bp upstream of the initiation codon. RT-PCR and promoter analyses revealed that fkp1-1 results in knockdown of FKP1 predominantly in tapetum. Electron microscopy showed that the mutation affected the development of tapetum-specific lipid-containing organelles (elaioplast and tapetosome), causing the deficient formation of fkp1-1 pollen coats. These results suggest that both elaioplasts, which accumulate vast amount of sterol esters, and tapetosomes, which are unique oil-accumulating structures, require the MVA pathway for development. Null alleles of fkp1 were male-gametophyte lethal upon pollen tube elongation, whereas female gametophytes were normal. These results show that the MVA pathway is essential, at least in tapetal cells and pollen grains, for the development of tapetum-specific organelles and the fertility of pollen grains.

Identification of kaonashi mutants showing abnormal pollen exine structure in Arabidopsis thaliana.

Exine, the outermost architecture of pollen walls, protects male gametes from the environment by virtue of its chemical and physical stability. Although much effort has been devoted to revealing the mechanism of exine construction, still little is known about it. To identify the genes involved in exine formation, we screened for Arabidopsis mutants with pollen grains exhibiting abnormal exine structure using scanning electron microscopy. We isolated 12 mutants, kaonashi1 (kns1) to kns12, and classified them into four types. The type 1 mutants showed a collapsed exine structure resembling a mutant of the callose synthase gene, suggesting that the type 1 genes are involved in callose wall synthesis. The type 2 mutant showed remarkably thin exine structure, presumably due to defective primexine thickening. The type 3 mutants showed defective tectum formation, and thus type 3 genes are required for primordial tectum formation or biosynthesis and deposition of sporopollenin. The type 4 mutants showed densely distributed baculae, suggesting type 4 genes determine the position of probacula formation. All identified kns mutants were recessive, suggesting that these KNS genes are expressed in sporophytic cells. Unlike previously known exine-defective mutants, most of the kns mutants showed normal fertility. Map-based cloning revealed that KNS2, one of the type 4 genes, encodes sucrose phosphate synthase. This enzyme might be required for synthesis of primexine or callose wall, which are both important for probacula positioning. Analysis of kns mutants will provide new knowledge to help understand the mechanism of biosynthesis of exine components and the construction of exine architecture.

RNA interference of the Arabidopsis putative transcription factor TCP16 gene results in abortion of early pollen development.

Pollen development is a fundamental and essential biological process in seed plants. Pollen mother cells generated in anthers undergo meiosis, which gives rise to haploid microspores. The haploid cells then develop into mature pollen grains through two mitotic cell divisions. Although several sporophytic and gametophytic mutations affecting male gametogenesis have been identified and analyzed, little is known about the underlying molecular mechanism. In this study, we investigated the function of the TCP16 gene, which encodes a putative transcription factor. Expression analysis of the promoter::GUS fusion gene revealed that TCP16 transcription occurred predominantly in developing microspores. GUS expression began at the tetrad stage and markedly increased in an early unicellular stage. Transgenic plants harboring a TCP16 RNA interference (RNAi) construct generated equal amounts of normal and abnormal pollen grains. The abnormal pollen grains exhibited morphological abnormality and degeneration of genomic DNA. The defective phenotype of the RNAi plants was first detectable at the middle of the unicellular stage. Our results therefore suggest that TCP16, a putative transcription factor, plays a crucial role in early processes in pollen development.