Esophageal self-expandable stent material and mesh grid density are the major determining factors of external beam radiation dose perturbation: results from a phantom model.

BACKGROUND: Self-expandable esophageal stents are increasingly used for palliation or as an adjunct to chemoradiation for esophageal neoplasia. The optimal esophageal stent design and material to minimize dose perturbation with external beam radiation are unknown. We sought to quantify the deviation from intended radiation dose as a function of stent material and mesh density design. METHODS: A laboratory dosimetric film model was used to quantify perturbation of intended radiation dose among 16 different esophageal stents with varying material and stent mesh density design. RESULTS: Radiation dose enhancement due to stent backscatter ranged from 0 % to 7.3 %, collectively representing a standard difference from the intended mean radiation dose of 1.9 (95 % confidence interval [CI] 1.5 - 2.2). This enhancement was negligible for polymer-based stents and approached 0 % for the biodegradable stents. In contrast, all metal alloy stents had significant radiation backscatter; this was largely determined by the density of mesh design and not by the type of alloy used. CONCLUSIONS: Stent characteristics should be considered when selecting the optimal stent for treatment and palliation of malignant esophageal strictures, especially when adjuvant or neo-adjuvant radiotherapy is planned.

Enhanced host-guest electrochemical recognition of herbicide MCPA using a ß-cyclodextrin carbon nanotube sensor.

An electrochemical sensor for the determination of the chlorophenoxy herbicide MCPA has been developed, based on a combination of multi-walled carbon nanotubes with incorporated ß-cyclodextrin and a polyaniline film modified glassy carbon electrode. The proposed molecular host-guest recognition based sensor has a high electrochemical sensitivity for the determination of MCPA. The electrochemical behaviour of MCPA at the chemically modified electrode was investigated in detail by cyclic voltammetry. The results indicate that the ß-CD/MWCNT modified glassy carbon electrode exhibits efficient electrocatalytic oxidation of MCPA with high sensitivity, stability and lifetime. The analytical characteristics of this film were used for the quantitative determination of MCPA in natural waters. Cyclic voltammetry in phosphate buffer solution at pH 6.0, allowed the development of a method to determine MCPA, without any previous steps of extraction, clean-up, or derivatization, in the range of 10-100 µmol L(-1), with a detection limit of 0.99 µmol L(-1) in water. The results were statistically compared with those obtained through an established high-performance liquid chromatography technique, no significant differences having been found between the two methods.

Air-kerma strength determination of a 169Yb high dose rate brachytherapy source.

The increased demand for high dose rate (HDR) brachytherapy as an alternative to external beam radiotherapy has led to the introduction of a HDR brachytherapy isotope 169Yb. This source offers a dose rate similar to 192Ir HDR sources, at about one fourth the effective photon energy. This work presents the calibration of this source in terms of air-kerma strength, based on an adaptation of the current, National Institute of Standards and Technology traceable, in air measurement technique currently used for 192Ir HDR sources. Several additional measurement correction factors were required, including corrections for air scatter, air attenuation, and ion recombination. A new method 169Yb is introduced for determining the ion chamber calibration coefficient Nk(169Yb). An uncertainty analysis was also performed, indicating an overall measurement expanded uncertainty in the air-kerma strength (k=2) of 2.2%.

Differential expression and imprinting status of Ins1 and Ins2 genes in extraembryonic tissues of laboratory mice.

There are two functional insulin genes in the mouse genome. The Ins2 gene is imprinted and expressed monoallelically from the paternal allele in the yolk sac. In the present study we have re-examined the imprinting status of Ins1. We found that Ins1 is not expressed in the yolk sac of several laboratory mouse strains. The asynchrony of replication at the wild type locus was significantly lower than at imprinted loci and was more similar to non-imprinted loci. Finally, we have taken the advantage of the Ins1(neo) allele created by homologous recombination to examine the allelic usage at this locus. We observed that the neo gene inserted at the Ins1 locus was expressed from both the paternally and the maternally transmitted allele. Therefore, the Ins1 gene does not share any of the basic properties of imprinted genes. On the basis of these data, we concluded that Ins1 locus is unlikely to be imprinted in common laboratory mice.

Behavioral anatomy of the abdominal arteries.

For surgical practice, behavioral anatomy is more important than variational anatomy. It has been possible, indeed, to define rules and behavioral explanations that allow us to understand and thus memorize easily the overwhelming number of variations in the abdominal blood supply. Variational anatomy is like the wiring diagram of a television set, whereas behavioral anatomy is its remote controller.

Primary structure of and studies on Acanthamoeba actophorin.

We determined the amino acid sequence of the actin monomer binding/actin filament severing protein actophorin from Acanthamoeba castellanii by automated Edman degradation of peptide fragments and by sequencing of full-length cDNA. Actophorin consists of 138 amino acids (calculated molecular weight of 15,543) and shares a high degree of sequence similarity to other low molecular weight actin monomer sequestering proteins, especially vertebrate cofilin, vertebrate actin depolymerizing factor/destrin, and echinoderm depactin. Actophorin is smaller and does not contain a nuclear localization sequence like the related vertebrate proteins. Southern blot analysis indicates that actophorin is a single-copy gene; however, Northern blots show two distinct mRNA species of 1 and 0.9 kb in size. Homogeneous recombinant actophorin purified from Escherichia coli is indistinguishable from the native protein in its physical properties and in biochemical assays of its interaction with actin, but is less reactive with three monoclonal antibodies raised against the native protein. The NH2 terminus of native actophrin is blocked, while the initiating methionine residue is removed from recombinant actophorin. This difference has no measurable effect on activity. By fluorescent antibody staining of Acanthamoeba, actophorin colocalizes with actin filaments in the cortical cytoplasm, especially at the leading edge of the cell. Additionally, actophorin binds phosphatidylinositol 4',5'-bisphosphate. The recombinant actophorin forms X-ray diffraction quality crystals of superior quality in poly(ethylene glycol)/2-propanol and, like the native crystal form, belongs to space group P2(1)2(1)2(1).

Amphibian intestinal villin: isolation and expression during embryonic and larval development.

An actin-binding protein of M(r) 105,000 has been isolated from anuran amphibian intestinal mucosa. Polyclonal antibodies directed against chicken and pig intestinal villins and anti-porcine villin headpiece monoclonal antibody crossreact with the amphibian M(r) 105,000 protein. Furthermore, the latter possesses an NH2-terminal sequence that is very homologous to those of avian and mammalian villins. In addition, polyclonal antibodies directed against amphibian intestinal M(r) 105,000 protein crossreact with chicken and mouse intestinal epithelial cell villins. These data indicate that the amphibian intestinal M(r) 105,000 protein is immunologically and structurally related to villin, an actin-binding protein expressed in specific epithelial tissues in vertebrates. Morphological, immunocytochemical and immunoblotting techniques were then used to investigate the expression of villin during embryonic and larval intestinal development of Xenopus laevis. Villin is not found in the egg or the endoderm of the early embryo. It is first detected just before hatching in the apical domain of endodermal cells at a time when few surface microvilli are visible by transmission electron microscopy. In the newly hatched larva, villin accumulates as these cells differentiate. These results provide a detailed developmental profile of Xenopus intestinal villin expression and demonstrate that this protein is a useful marker for the presumptive intestinal endoderm.

The two forms of bovine heart 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase result from alternative splicing.

Purified bovine heart 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) showed two bands with subunit M(r) of 58,000 and 54,000 when analysed by SDS/PAGE. Both the 58,000- and 54,000-M(r) forms were phosphorylated by cyclic AMP-dependent protein kinase (PKA) and by protein kinase C (PKC) in vitro. Phosphorylation by PKA decreased the apparent Km of PFK-2 for one of its substrates, fructose 6-phosphate, while phosphorylation by PKC did not correlate with any change in PFK-2 activity. The differences between the 58,000- and 54,000-M(r) forms were studied by electroblotting, peptide mapping and microsequencing. Residues 451-510, which correspond to exon 15 in the rat and contain phosphorylation sites for PKA (Ser-466) and PKC (Thr-475), were absent from the 54,000-M(r) form. Peptide mapping after phosphorylation by [gamma-32P]MgATP and PKC showed a phosphorylated peptide containing Thr-475, which was present in the 58,000-M(r) form but not in the 54,000-M(r) form. The fact that the latter form was phosphorylated by PKC and PKA suggests that other phosphorylation sites for PKA and PKC are located outside the region encoded by exon 15. Finally, analysis of RNA from bovine heart showed that the tissue contains two PFK-2/FBPase-2 mRNAs, only one of which was recognized by a probe specific to the region coding for Ser-466 and Thr-475. Taken together, these findings demonstrate that the 58,000- and 54,000-M(r) forms of bovine heart PFK-2/FBPase-2 result from alternative splicing of the same primary transcript.

One-stage endometrial ablation: results in 200 cases.

Until now, endometrial ablation (EA) included at least three steps: (1) D & C or hysteroscopic endometrial sampling; (2) Danazol treatment; and (3) the ablation. We have found that step (2) can be omitted if EA is performed between days 2-7 of the menses. This permits to combine steps (1) and (3) into a single stage EA which is a very simple, feasible, efficient and safe treatment for dysfunctional bleeding. Simple: because one stage without hormonal pretreatment, causing almost no pain and only a minimal time off work. It is not more of a burden than D & C with hysteroscopy. General anaesthesia is used in 94% of our patients. Feasible: in one case only (GOPO) the cervix could not be dilated wide enough. Efficient: good results in 97.5%: 67% complete amenorrhea, 24% slight menstrual spotting for a maximum of 2 days, 6% reduced flow and 0.5% normal flow. There are 2.5% failures. When menorrhagia is accompanied by otherwise unexplained dysmenorrhea, the pain is completely cured in 73%, unchanged in 7% and greatly improved in 20%. Safe: mild complications in 2.5% only. We have also combined the two main methods of endometrial destruction: electrocoagulation and Nd/Yag laser. Our 97.5% good results, however, is not a definite proof that a combination of these two techniques is better than either technique alone.

The blood supply of the stomach.

156 abdominal preparations were explored by arteriography, corrosion and dissection. The stomach is vascularized by four well-anastomosed main arteries: the arteria gastrica dextra and sinistra and the arteria gastroepiploica dextra and sinistra. Other important vessels include: the arteria gastroduodenalis, the arteriae gastricae breves for the upper half of the greater curvature, a posterior gastric artery (36%), an accessory left gastric artery (12%) and an arteria supraduodenalis. The main vessels give rise to some very specific collaterals, e.g. the omental arteries that may form an omental arcade (44%), supra- and infra-pyloric branches, retroduodenal branches, rami cardiaci, esophagei and tuberales and an accessory left hepatic artery. The gastroduodenal artery always arises at a fixed point.

One hundred elective resections of the left colon and rectum with unprotected manual anastomosis.

One hundred consecutive elective resections with hand suture of the left colon and rectum without a protective colostomy are reported. The absence of clinical fistulas, wound infections and abcesses indicates the safety and the feasability of this approach. There was a two per cent mortality rate. The article stresses the importance of a good suturing technique, good preparation, the judicious use of anti-anaerobic drugs, the use of plastic ring drapes and the changing of gloves, drapes and instruments before wound closure. The absence of leakage and of septic complications lowers dramatically the overall complication rate.

Systematisation of the arteries in the splenic hilus.

156 abdominal preparations were explored by arteriography, corrosion and dissection. Within the meanders of the splenic artery a basic pattern can be traced. The division of the artery can easily be summarized by introducing the term of a truncus lienogastroepiploicus. The short gastric arteries are always present, and usually they are longer and more important than may appear from their name. In nearly half of the preparations (52%) an artery for the extremitas lienalis posterior is found; an artery for the extremitas lienalis anterior is very exceptional. A posterior gastric artery can be identified (36%) but it must be distinguished from several other vessels. The arteria colli pancreatis (for the neck of the pancreas) is a constant vessel that may have a superior (usually arteria lienalis) or an inferior origin (arteria mesenterica superior). It commonly supplies the transverse pancreatic artery and often the prepancreatic arcade. The arteria corporis pancreatis, too, is a constant artery. The pancreatic tail is thoroughly irrigated by usually more than one arteria caudae pancreatis. An important part of the greater curvature is not accompanied by the left gastroepiploic artery, but is supplied by the arteriae gastricae breves.

Single-stage subcutaneous breast-prosthesis implantation and modified radical mastectomy for invasive carcinoma.

In eighteen patients modified radical mastectomy for invasive carcinoma was immediately followed by breast reconstruction. The prosthesis was placed subcutaneously. There were no infections and no definitively lost prostheses. One prosthesis had to be replaced subpectorally after 55 days due to a small skin necrosis occurring after radiotherapy. One hematoma had to be evacuated and one small skin necrosis was excised and sutured per primam. There were no local recurrences but the follow-up is short (3 years and 4 months). Postoperative radio- and chemotherapy were not affected by the reconstruction.

The branches of the celiac trunk.

156 abdominal preparations were explored by arteriography, corrosion and dissection. Classification of the celiac trunk becomes easy if one considers the trunk to be composed of three main stems: the splenic, the hepatic and the left gastric artery, other vessels being less important collaterals. Usually, the celiac trunk bifurcates into the splenic and the hepatic artery; the left gastric artery is a mobile vessel whose origin may slide between the aorta, all over the celiac trunk up to a trifurcation. The direction of the celiac trunk is influenced by the topography of the pancreatic neck and by the origin of the hepatic artery: if the celiac trunk is not the origin of the hepatic artery it is not directed to the right but to the left. It is the hepatic artery that pulls the celiac trunk to the right. Variations in the origin of the splenic artery are exceptional. In contrast to adults, the diameter of the hepatic artery in young children is larger than that of the splenic artery.

Arcus paracolicus.

The paracolic arcade is the most important vessel for the blood supply of the colon. It can be compared with the felly of a wheel, whose spokes are the colic arteries. It is the immediate source of the colic supply and the most important way for collateral circulation between the colic arteries and even between the superior and inferior mesenteric arteries.

Re-evaluation of the colic irrigation from the inferior mesenteric artery.

156 abdominal preparations were explored by arteriography, corrosion and dissection. The arteria mesenterica inferior (AMI) ends by bifurcating into the two arteriae rectales superiores. The key to the interpretation of the AMI is the recognition of an arteria colosigmoidea that gives off one or more rami sigmoidei. In the presence of an arteria or ramus colic. sin. access, usually from the superior mesenteric artery, the left colic artery is absent, atrophic or displaced. The sigmoid branches (usually three) arise from the colosigmoid, the left colic or the distal portion of the AMI. Usually, the last sigmoid artery gives branch to the rectosigmoid colon. The rectosigmoid artery arises from the AMI between arteria sigmoidea ima and the terminal bifurcation of the former. It may be replaced by the descending branch of the a. sigmoidea ima. They irrigate an extensive part of the anterior wall of the bowel.

A new look at the blood supply of the ileocolic angle.

87 ileocolic preparations are studied by means of postmortem arteriography combined with dissection and corrosion. The ileocolic stem is to be continued beyond the colic and ileal branches up to its division into the caecal branches. This allows to distinguish a long ileocolic trunk which is the direct origin of the different tributaries and which ends into one or both caecal arteries. An arteria colica dextra from the ileocolic artery cannot be supported. Many rules are established that govern the relations between the various collaterals, and several conclusions of theoretical and practical importance are made.

A simple, new system for maintaining measured quantities of saline cold and sterile for thermodilution cardiac output measurement.

A new, simple system for cooling and maintaining prefilled syringes of injectate in a dry, sterile environment for thermodilution cardiac output using a thermoelectric cold plate is described. Rates and uniformity of cooling were studied. Uniform cooling is achieved in about 60 minutes if refrigerated injectate is used.