Oncological results of extended resection for locally advanced rectal cancer: the value of postirradiation MRI in predicting local recurrence

AIM

The primary purpose of this study was to analyse the overall survival and local recurrence rate after extended resection of locally advanced rectal cancer. The second aim was to determine the ability of the response to radiological irradiation to predict R0 resection.

METHOD

A retrospective study was performed of 94 consecutive patients with locally advanced rectal cancer operated on at the Helsinki University Hospital, Helsinki, Finland between 2005 and 2013. Data were collected from patient records. All patients were treated with an en bloc resection. Sixty-two patients received preoperative long-term chemoradiotherapy.

RESULTS

The 30-day mortality was 3.2%. Local recurrence occurred in 10 (10.6%) patients. The cumulative 1-, 3- and 5-year overall survival to each year was 89.4%, 68.3% and 51.8%. The most important prognostic factor for both local recurrence (P = 0.006) and survival (P = 0.003) was an R0 resection. A poor or no response seen on posttreatment MRI predicted local recurrence (P = 0.045) and decreased disease-free survival in patients treated curatively (P = 0.052). The histological tumour regression grade was not associated with local recurrence or survival.

CONCLUSION

Multivisceral resection offers a 5-year survival of over 50% and local control of advanced rectal cancer in nearly 90% of carefully selected patients.

Facultative and obligate slave making in Formica ants

Here we show for the first time that the presumed facultative slave-making ant Formica subintegra does not activate outside its nest until July and August, when it raids slaves. A comparative behavioral study of seasonal and daily activities, retrieval of prey, and nest maintenance of F. subintegra, the obligate slavemaker Polyergus breviceps, and the facultative Formica subnuda, shows that the behavioral repertory of F. subintegra closely resembles that of P. breviceps and clearly differs from the repertory of F. subnuda. Unlike P. breviceps, F. subintegra has retained some nest-building activity which, owing to lack of competence, does not contribute to nest maintenance. We suggested earlier that F. subintegra is probably an obligate slavemaker, because it always has in its colonies a large proportion of slaves of the total workforce, whereas F. subnuda fares well even without slaves. This, coupled with no foraging in early summer and a raiding period later on, strongly suggests that F. subintegra is an obligate slave-making ant.

Control of red fox (Vulpes vulpes) fertility with cabergoline: dose response and timing of intervention

Cabergoline, a potent dopamine agonist and inhibitor of prolactin secretion, was investigated as a potential fertility control agent in the red fox ( Vulpes vulpes). Sixty silver fox vixens were selected randomly and artificially inseminated. Cabergoline was fed to groups of 12 vixens in a minced beef ration either as a single dose of 25, 50 or 100 microg kg(-1), or a dose of 50 microg kg(-1) that was repeated 2 days later (2 x 50 microg kg(-1)). Four foxes from each group of 12 were given cabergoline at day 28, day 35 or day 48 after artificial insemination, and a control group of four foxes was used as a comparison for each dose day. In a separate trial, two groups of five foxes were selected randomly from the farm population and fed 100 microg kg(-1) of either cabergoline or a placebo each day from day 42 to day 46 of pregnancy. Foxes that received single doses of cabergoline of 100 microg kg(-1) or 2 x 50 microg kg(-1) aborted at day 28, but the same doses did not result in abortions when administered on days 35 and 48. Although lactation was not terminated in groups that received a single or double dose of cabergoline, increased post-natal cub mortality was associated with cabergoline administration. Growth of cubs between 4 and 8 weeks of age was not inhibited in vixens that received cabergoline. Doses of 100 microg cabergoline kg(-1) administered each day from day 42 to day 46 resulted in abortions and terminated lactation. The capacity of single doses of cabergoline to cause abortions in the red fox during mid- rather than late pregnancy is contrary to reported observations for the domestic dog. This finding indicates that luteotrophic support of the corpus luteum by prolactin may be more important at mid-pregnancy in the red fox. The results of this study support previous field observations that cabergoline delivered in bait affects the reproductive success of vixens and may be a practical adjunct to the lethal control of wild red foxes in Australia.

Control of red fox (Vulpes vulpes) fertility with cabergoline: dose response and timing of intervention

Cabergoline, a potent dopamine agonist and inhibitor of prolactin secretion, was investigated as a potential fertility control agent in the red fox ( Vulpes vulpes). Sixty silver fox vixens were selected randomly and artificially inseminated. Cabergoline was fed to groups of 12 vixens in a minced beef ration either as a single dose of 25, 50 or 100 microg kg(-1), or a dose of 50 microg kg(-1) that was repeated 2 days later (2 x 50 microg kg(-1)). Four foxes from each group of 12 were given cabergoline at day 28, day 35 or day 48 after artificial insemination, and a control group of four foxes was used as a comparison for each dose day. In a separate trial, two groups of five foxes were selected randomly from the farm population and fed 100 microg kg(-1) of either cabergoline or a placebo each day from day 42 to day 46 of pregnancy. Foxes that received single doses of cabergoline of 100 microg kg(-1) or 2 x 50 microg kg(-1) aborted at day 28, but the same doses did not result in abortions when administered on days 35 and 48. Although lactation was not terminated in groups that received a single or double dose of cabergoline, increased post-natal cub mortality was associated with cabergoline administration. Growth of cubs between 4 and 8 weeks of age was not inhibited in vixens that received cabergoline. Doses of 100 microg cabergoline kg(-1) administered each day from day 42 to day 46 resulted in abortions and terminated lactation. The capacity of single doses of cabergoline to cause abortions in the red fox during mid- rather than late pregnancy is contrary to reported observations for the domestic dog. This finding indicates that luteotrophic support of the corpus luteum by prolactin may be more important at mid-pregnancy in the red fox. The results of this study support previous field observations that cabergoline delivered in bait affects the reproductive success of vixens and may be a practical adjunct to the lethal control of wild red foxes in Australia.

Genomic organization of the human catechol O-methyltransferase gene and its expression from two distinct promoters

Human genomic DNA fragments containing catechol O-methyltransferase (COMT) sequences were isolated and the exon-intron structure analysed by sequencing, PCR and comparing to the human COMT cDNA sequences. The gene contains six exons, of which exons 1 and 2 are noncoding. MB-ATG and S-ATG codons, responsible for the initiation of translation of the membrane-bound (MB) and soluble (S) forms of the enzyme, are located in exon 3. Two distinct COMT-specific transcripts, 1.3 kb and 1.5 kb, were detected in various human tissues and cell lines. Different quantities of the shorter COMT-specific mRNA in the tissues studied suggest a tissue-specific regulation of the COMT gene at transcriptional level. Mapping of the 5' ends of the COMT mRNAs showed that transcription initiates at multiple sites in two separate DNA regions, which are preceded by functional promoter sequences. The proximal promoter (P1), located between the two translation initiation codons and extending approximately 200 bp upstream of the MB-ATG initiation codon, apparently gives rise to the 1.3-kb S-COMT mRNA (S-mRNA). The distal promoter (P2) is located in a DNA fragment in front of and partly overlapping the transcription-start region of the 1.5-kb transcript, suggesting that it controls the expression of this MB-mRNA. Similarities between the rat and human COMT gene promoters are analyzed.

In vitro culture of silver fox embryos

This experiment was designed to establish in vitro culture methods for silver fox embryos in order to develop the methods for evaluation of the post-thaw viability of frozen embryos in future studies. Artificially inseminated silver fox females were killed humanely on predetermined days after insemination and oviducts and uteri were flushed for embryos. The embryos were cultured in modified TCM 199 or in the same medium supplemented with silver fox oviductal tissue suspension for varying periods, from 6 days to 3 weeks. A total of 60 embryos was recovered. Only embryos beyond the 8-cell stage up to expanded blastocysts developed in vitro (28 % of all embryos). Early stage blastocysts developed most reliably and were of the best quality.

Cloning and characterization of human placental catechol-O-methyltransferase cDNA

Catechol-O-methyltransferase (COMT) cDNA clones were isolated from a human placental cDNA library using synthetic oligonucleotides as probes. All four positive clones isolated contained an open reading frame, which potentially coded for a 24.4-kD polypeptide, presumably corresponding to the cytoplasmic form of the COMT (S-COMT). In addition to the S-COMT sequences, two of the clones carried extensions in the 5' end, which potentially coded for a 50-amino-acid peptide extending the S-COMT reading frame. This sequence contained a stretch of signal sequence-like hydrophobic amino acids in its amino terminus. The deduced human COMT polypeptide had 80% similarity with the previously characterized rat COMT. Expression of one of the cDNA clones in human K-562 cells resulted in cell clones with 3- to 10-fold increased COMT activity. Cell-free translation of transcripts synthesized in vitro from one of the short cDNAs yielded a 26-kD product, similar in size to human S-COMT. Translation of transcripts from one of the long cDNAs gave 30-kD and 26-kD polypeptides, suggesting translation initiation from two different AUG initiation codons. The 30-kD protein, but not the 25-kD protein, associated with microsomal membranes in translation lysates. A potential polyadenylation signal AATTAA was detected in the 3' ends of two of the clones 265 nucleotides downstream from the COMT translation termination codon. RNA blotting on human placental RNA revealed a 1.5-kb-long COMT-specific transcript. DNA analysis suggested that human, as well as rat, canine and monkey cells have one gene for COMT.

Molecular cloning and characterization of rat liver catechol-O-methyltransferase

The coding sequence of rat liver catechol-O-methyl-transferase (COMT; EC 2.1.1.6) was determined from rat cDNA and genomic libraries were screened with DNA probes and specific antiserum. The open reading frame consisted of 663 nucleotides coding for a 221-amino acid (aa) polypeptide with a deduced Mr of 24,747. No obvious hydrophobic signal sequence, membrane-spanning domains, or potential N-glycosylation sites were found in this sequence. The identity of the clone and the accuracy of the sequence was verified by direct aa sequencing of the tryptic peptides derived from the purified rat liver enzyme. Primer extension analysis showed that the transcription start point of the rat liver COMT mRNA was 450 bp upstream from the translation start codon. A putative polyadenylation signal (ATTAAA) was found in the 3'-noncoding region. The predicted size of the COMT transcript was 1.8-2.0 kb, which could be confirmed from Northern hybridization analyses of the isolated rat liver mRNA. One polypeptide of 25 kDa, could be immunoprecipitated with anti-COMT antibody from in vitro translation of rat liver mRNA. Employing the DNA blot analysis only one COMT-encoding gene was found in the rat genome.