Hemopatch to Prevent Lymphatic Leak after Robotic Prostatectomy and Pelvic Lymph Node Dissection: A Randomized Controlled Trial.

This study investigates whether the application of Hemopatch, a novel hemostatic patch, could prevent lymphatic leak after robotic-assisted radical prostatectomy (RARP) and bilateral pelvic lymph node dissection (BPLND). This is a prospective, single-center, phase III randomized controlled trial investigating the efficacy of Hemopatch in preventing lymphatic leak after RARP and BPLND. Participants were randomized to receive RARP and BPLND, with or without the use of Hemopatch, with an allocation ratio of 1:1. The primary outcome is the total drain output volume. The secondary outcomes include blood loss, operative time, lymph node yield, duration of drainage, drain output per day, hospital stay, transfusion and 30-day complications. A total of 32 patients were recruited in the study. The Hemopatch group had a significantly lower median total drain output than the control group (35 mL vs. 180 mL, p = 0.022) and a significantly lower drain output volume per day compared to the control group (35 mL/day vs. 89 mL/day, p = 0.038). There was no significant difference in the other secondary outcomes. In conclusion, the application of Hemopatch in RARP and BPLND could reduce the total drain output volume and the drain output volume per day. The use of Hemopatch should be considered to prevent lymphatic leakage after RARP and BPLND.

Management outcome of NPC-related and non-NPC-related brain abscess in Hong Kong.

OBJECTIVES: (1) To review the patient profile, management outcome and prognostic factors of brain abscess; (2) To compare the neurological outcome of nasopharyngeal carcinoma (NPC)-related brain abscess with non-NPC related brain abscess. METHOD: Retrospective review of consecutive patients diagnosed (radiologically and/or microbiologically) with brain abscess in a regional neurosurgical center in Hong Kong over a nine year period. RESULTS: Fifty-four patients were recruited into this study. There were 37 male and 17 female patients. Eighteen (33%) patients had previous radiotherapy for nasopharyngeal carcinoma. Only 31 (57%) patients had fever on presentation. White cell count and/or C-reactive protein, was raised in 41 (76%) patients on admission. Surgical drainage was carried out in 49 (91%) patients, either by aspiration through a craniotomy, by drainage with corticotomy, or excision of the abscess. Abscess culture was positive in 45 (83%) patients. Common organisms isolated included Streptococcus species (35%) and Peptostreptococcus species (18%). Anaerobes were isolated in 50% of the NPC-related abscesses. The mean follow-up time was 34 months. At the 6 months interval, 24 (44%) patients had good recovery. Favorable outcome was achieved in 30 (55%) patients. NPC-related brain abscess was associated with unfavorable neurological outcome (33%, p = 0.04). There was also a trend towards higher in-patient mortality in patients with NPC-related brain abscess (22%, p = 0.08). CONCLUSION: Brain abscess carried a substantial morbidity and mortality despite aggressive surgical and medical treatment. Patients with NPC-related brain abscess had a higher mortality and unfavorable neurological outcome.

Determinants of R-loop formation at convergent bidirectionally transcribed trinucleotide repeats.

R-loops have been described at immunoglobulin class switch sequences, prokaryotic and mitochondrial replication origins, and disease-associated (CAG)n and (GAA)n trinucleotide repeats. The determinants of trinucleotide R-loop formation are unclear. Trinucleotide repeat expansions cause diseases including DM1 (CTG)n, SCA1 (CAG)n, FRAXA (CGG)n, FRAXE (CCG)n and FRDA (GAA)n. Bidirectional convergent transcription across these disease repeats can occur. We find R-loops formed when CTG or CGG and their complementary strands CAG or CCG were transcribed; GAA transcription, but not TTC, yielded R-loops. R-loop formation was sensitive to DNA supercoiling, repeat length, insensitive to repeat interruptions, and formed by extension of RNA:DNA hybrids in the RNA polymerase. R-loops arose by transcription in one direction followed by transcription in the opposite direction, and during simultaneous convergent bidirectional transcription of the same repeat forming double R-loop structures. Since each transcribed disease repeat formed R-loops suggests they may have biological functions.

Diversity of hopanoids and squalene-hopene cyclases across a tropical land-sea gradient.

Bacterial hopanoids are ubiquitous in Earth surface environments. They hold promise as environmental and ecological biomarkers, if the phylogeny and physiological drivers of hopanoid biosynthesis can be linked with the distribution of hopanoids observed across a breadth of samples. Here we survey the diversity of hopanoid cyclases from a land-sea gradient across the island of San Salvador, in the easternmost part of the Bahamas. The distribution of lipids was determined for the same sites, for the first time overlaying quantification of bacteriohopanepolyols with sqhC phylogeny. The results are similar to previous reports: environmental sqhCs average < 65% translated amino acid identity to their closest named relatives, and sequences from putative Proteobacteria dominate. Additionally, a new and apparently ubiquitous group of marine hopanoid producers is identified; it has no identifiable close relatives. The greatest diversity of hopanoid lipids occurs in soil, but hopanoids represent a minor fraction of total soil-derived lipids. Marine samples contain fewer identifiable hopanoids, but they are more abundant as a fraction of the total extractable lipids. In soil, the dominant compounds are 35-aminobacteriohopane-32,33,34-triol and adenosylhopane. In an upper estuarine sample, bacteriohopanetetrol and 32,35-anhydrobacteriohopanetetrol dominate; while in lower estuarine and open marine samples, the most abundant are bacteriohopanetetrol and bacteriohopaneribonolactone. Cyclitol ethers are trace components in the soil, absent in the estuary, and of moderate abundance in the open marine setting, suggesting a dominant marine source. Conversely, aminotriol and aminotetrol decrease in abundance or disappear completely from land to ocean, while 2-methyldiplopterol shows the opposite trend. Small quantities of 2-methylbacteriohopanepolyols are detectable in all samples. The overall hopanoid distributions may correlate to the major phylogenetic families of hopanoid producers or to the environments in which they are found.

Murine bilateral retinoblastoma exhibiting rapid-onset, metastatic progression and N-myc gene amplification.

Human retinoblastoma is a pediatric cancer initiated by RB gene mutations in the developing retina. We have examined the origins and progression of retinoblastoma in mouse models of the disease. Retina-specific inactivation of Rb on a p130-/- genetic background led to bilateral retinoblastoma with rapid kinetics, whereas on a p107-/- background Rb mutation caused predominantly unilateral tumors that arose with delayed kinetics and incomplete penetrance. In both models, retinoblastomas arose from cells at the extreme periphery of the murine retina. Furthermore, late retinoblastomas progressed to invade the brain and metastasized to the cervical lymph nodes. Metastatic tumors lacking Rb and p130 exhibited chromosomal changes revealed by representational oligonucleotide microarray analysis including high-level amplification of the N-myc oncogene. N-myc was found amplified in three of 16 metastatic retinoblastomas lacking Rb and p130 as well as in retinoblastomas lacking Rb and p107. N-myc amplification ranged from 6- to 400-fold and correlated with high N-myc-expression levels. These murine models closely resemble human retinoblastoma in their progression and secondary genetic changes, making them ideal tools for further dissection of steps to tumorigenesis and for testing novel therapies.

Slipped (CTG).(CAG) repeats of the myotonic dystrophy locus: surface probing with anti-DNA antibodies.

At least 15 human diseases have been associated with the length-dependent expansion of gene-specific (CTG).(CAG) repeats, including myotonic dystrophy (DM1) and spinocerebellar ataxia type 1 (SCA1). Repeat expansion is likely to involve unusual DNA structures. We have structurally characterized such DNA, with (CTG)(n).(CAG)(n) repeats of varying length (n=17-79), by high-resolution gel electrophoresis, and have probed their surfaces with anti-DNA antibodies of known specificities. We prepared homoduplex S-DNAs, which are (CTG)x.(CAG)y where x=y, and heteroduplex SI-DNAs, which are hybrids where x>y or x

Slipped-strand DNAs formed by long (CAG)*(CTG) repeats: slipped-out repeats and slip-out junctions.

The disease-associated expansion of (CTG)*(CAG) repeats is likely to involve slipped-strand DNAs. There are two types of slipped DNAs (S-DNAs): slipped homoduplex S-DNAs are formed between two strands having the same number of repeats; and heteroduplex slipped intermediates (SI-DNAs) are formed between two strands having different numbers of repeats. We present the first characterization of S-DNAs formed by disease-relevant lengths of (CTG)*(CAG) repeats which contained all predicted components including slipped-out repeats and slip-out junctions, where two arms of the three-way junction were composed of complementary paired repeats. In S-DNAs multiple short slip-outs of CTG or CAG repeats occurred throughout the repeat tract. Strikingly, in SI-DNAs most of the excess repeats slipped-out at preferred locations along the fully base-paired Watson-Crick duplex, forming defined three-way slip-out junctions. Unexpectedly, slipped-out CAG and slipped-out CTG repeats were predominantly in the random-coil and hairpin conformations, respectively. Both the junctions and the slip-outs could be recognized by DNA metabolizing proteins: only the strand with the excess repeats was hypersensitive to cleavage by the junction-specific T7 endonuclease I, while slipped-out CAG was preferentially bound by single-strand binding protein. An excellent correlation was observed for the size of the slip-outs in S-DNAs and SI-DNAs with the size of the tract length changes observed in quiescent and proliferating tissues of affected patients-suggesting that S-DNAs and SI-DNAs are mutagenic intermediates in those tissues, occurring during error-prone DNA metabolism and replication fork errors.