Sins of omission: A meta-research study evaluating the omission of operability in published retrospective comparisons of surgery with stereotactic body radiotherapy in patients with early-stage non-small cell lung cancer.

INTRODUCTION: Patients receiving stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC) are typically inoperable, in concordance with guidelines that advocate surgical resection as preferred treatment for operable patients. This differential treatment allocation complicates retrospective comparisons of surgery with SBRT by introducing the potential for confounding by operability. METHODS: PubMed was queried for manuscripts reporting primary data from retrospective comparisons of overall survival (OS) between patients undergoing surgery versus SBRT for early-stage NSCLC. Each manuscript was categorized for two outcomes: (1) whether treatment allocation was based on a determination of patient operability, and (2) whether a direct OS comparison between operable SBRT patients and surgically treated patients was included. Associations with variables of interest were measured with statistical significance prespecified at p < 0.10. RESULTS: From 3,072 manuscripts identified in our query, sixty-one analyses met screening criteria. Twenty-one (34 %) reported operability status influencing treatment allocation. These were more likely to be published in journals with a surgical focus (52 vs 20 %) and impact factor < 5 (81 vs 58 %), and to contain cohorts from institutional datasets (81 vs 55 %), and to have a radiation oncologist as first (43 vs 25 %) or senior (43 vs 28 %) author. Seven (11 %) manuscripts featured a direct OS comparison between SBRT and surgery. CONCLUSION: Nearly-two-thirds of peer-reviewed retrospective studies that have compared OS between surgery and SBRT for early-stage NSCLC lack information on patient operability status, and nearly 90% lack a direct comparison between operable SBRT patients and those receiving surgery.

Role of the trochlear nerve in eye abduction and frontal vision of the red-eared slider turtle (Trachemys scripta elegans).

Horizontal head rotation evokes significant responses from trochlear motoneurons of turtle that suggests they have a functional role in abduction of the eyes like that in frontal-eyed mammals. The finding is unexpected given that the turtle is generally considered lateral-eyed and assumed to have eye movements instead like that of lateral-eyed mammals, in which innervation of the superior oblique muscle by the trochlear nerve (nIV) produces intorsion, elevation, and adduction (not abduction). Using an isolated turtle head preparation with the brain removed, glass suction electrodes were used to stimulate nIV with trains of current pulses. Eyes were monitored via an infrared camera with the head placed in a gimble to quantify eye rotations and their directions. Stimulations of nIV evoked intorsion, elevation, and abduction. Dissection of the superior oblique muscle identified lines of action and a location of insertion on the eye, which supported kinematics evoked by nIV stimulation. Eye positions in alert behaving turtles with their head extended were compared with that when their heads were retracted in the carapace. When the head was retracted, there was a reduction in interpupillary distance and an increase in binocular overlap. Occlusion of peripheral fields by the carapace forces the turtle to a more frontal-eyed state, perhaps the reason for the action of abduction by the superior oblique muscle. These findings support why trochlear motoneurons in turtle respond in the same way as abducens motoneurons to horizontal rotations, an unusual characteristic of vestibulo-ocular physiology in comparison with other mammalian lateral-eyed species.

Comparison of the solution conformations of a human immunodeficiency virus peptidomimetic and its retro-inverso isomer using 1H NMR spectroscopy.

The solution conformations of the all L-alpha-peptide 1 and the corresponding retro-all D-alpha-peptide 2, two 20-metric peptides which generate antibodies that cross-react with the gp 120 envelop protein of human immunodeficiency virus-1 (HIV-1), have been investigated by high-field 1H NMR spectroscopy. Complete sequential and inter-residue interaction assignments were made from the 2D NMR spectra acquired at 500 MHz and 600 MHz in 40% deuterotrifluoroethanol (d3-TFE)/H2O at pH 2.3, and in 300 mM sodium dodecyl sulphate (SDS) in 100% D2O or 90% H2O/10% D2O at pH 2.6. Based on analysis of the nuclear Overhauser effect (NOE) and amide exchange data, peptide 1 and its retro-inverso isomer 2 in the polar solvent environment of 40% d3-TFE/H2O at pH 2.3 show very similar topological features. However, in the relatively non-polar 300 mM SDS micellar environment, peptides 1 and 2 exhibit differences in their solution structures in terms of the amide backbone and side-chain orientations. In particular, under the SDS micellar condition, peptide 1 maintains much of the secondary structure observed for this 20-mer peptide in 40% d3-TFE/H2O, pH 2.3, whereas peptide 2 adopts a more extended structure. These NMR results provide the first confirmation that the secondary structure of the all L-a-peptide 1 is maintained in both polar and non-polar environments, whereas the secondary structure and topology of the notionally equivalent retro-inverso isomer depends more on the solvent conditions. These results with the all L-a-peptide 1 and its retro-inverso isomer 2 provide important insight into the conformational influences of the C- and N-end group with L-alpha- and retro-D-alpha-isomer pairs in non-polar environments, and thus have general relevance to the design of bioactive retro-inverso peptidomimetic analogues related to immunogenic or hormonal peptides.

Conformational analysis of human growth hormone [6-13] peptide analogues.

The conformational analysis of a series of ten hGH[6-13] peptide analogues is reported. As part of our earlier studies, the alpha-aminosuccinimide modified fragment Asu11-hGH[6-13] has previously been identified as a potentiator of insulin activity in intravenous insulin tolerance tests, and various analogues have been subsequently designed, synthesised and employed to acquire structure-activity data. These studies have lead to the conclusion that the conformational characteristics at the C-terminus of each of the active peptide analogues is important to the biological activity. In the present investigation, molecular dynamics and simulated annealing techniques have been used to examine the accessible conformational states of the C-terminal region of ten different hGH[6-13] peptide analogues. Of these six are active peptide analogues while the other four show no biological activity. Examination of the conformer groups identified using this molecular dynamics approach showed a common conformational motif for each of the active peptides.

Antisense inhibition of the p65 subunit of NF-kappa B blocks tumorigenicity and causes tumor regression.

The NF-kappa B transcription factor, composed of two proteins, p50 and p65, is a pleiotropic activator that participates in the induction of a wide variety of cellular genes. Various cell adhesion molecules have NF-kappa B binding sites and may play an important role in inflammatory response, tumorigenicity, and metastasis. In an earlier study, we demonstrated that adhesion of diverse transformed cells was blocked by antisense inhibition of the p65 subunit of NF-kappa B. Since cell-substratum interactions play an important role in tumorigenicity, we reasoned that antisense p65 could inhibit tumorigenicity. In diverse transformed cell lines, phosphorothioate antisense oligonucleotides to p65 inhibited in vitro growth, reduced soft-agar colony formation, and eliminated the ability of cells to adhere to an extracellular matrix. Stable transfectants of a fibrosarcoma cell line expressing dexamethasone-inducible antisense RNA to p65 showed inhibition of in vitro growth and in vivo tumor development. In response to inducible expression of antisense RNA, a pronounced tumor regression was seen in nude mice. The administration of antisense but not sense p65 oligonucleotides caused a pronounced inhibition of tumorigenicity in nude mice injected with diverse tumor-derived cell lines. Inhibitors of NF-kappa B function may thus be useful in the treatment of cancer.

Evidence for differential functions of the p50 and p65 subunits of NF-kappa B with a cell adhesion model.

The p50 and p65 subunits of NF-kappa B represent two members of a gene family that shares considerable homology to the rel oncogene. Proteins encoded by these genes form homo- and heterodimers which recognize a common DNA sequence motif. Recent data have suggested that homodimers of individual subunits of NF-kappa B can selectively activate gene expression in vitro. To explore this possibility in a more physiological manner, murine embryonic stem (ES) cells were treated with phosphorothio antisense oligonucleotides to either p50 or p65. Within 5 h after exposure to phosphorothio antisense p65 oligonucleotides, cells exhibited dramatic alterations in adhesion properties. Similar findings were obtained in a stable cell line that expressed a dexamethasone-inducible antisense mRNA to p65. Although antisense oligonucleotides raised against both p50 and p65 elicited a significant reduction in their respective mRNAs, only the cells treated with antisense p50 maintained a normal morphology. However, 6 days following removal of leukemia-inhibiting factor, a growth factor which suppresses embryonic stem cell differentiation, adhesion properties of cells treated with the antisense p50 oligonucleotides were markedly affected. The ability of the individual antisense oligonucleotides to elicit differential effects on cell adhesion, a property dependent upon the stage of differentiation, suggests that the p50 and p65 subunits of NF-kappa B regulate gene expression either as homodimers or as heterodimers with other rel family members. Furthermore, the finding that reduction in p65 expression alone had profound effects on cell adhesion properties indicates that p65 plays an important role in nonstimulated cells and cannot exist solely complexed with the cytosolic inhibitory protein I kappa B.

Identification of a naturally occurring transforming variant of the p65 subunit of NF-kappa B.

Transcription factor NF-kappa B comprises two proteins, p50 and p65, that have sequence similarity to the v-rel oncogene. In primary hematopoietic cell populations an alternatively spliced form of NF-kappa B p65 mRNA was observed that encoded a protein designated p65 delta. Expression of the p65 delta cDNA in Rat-1 fibroblasts resulted in focus formation, anchorage-independent growth in soft agar, and tumor formation in athymic nude mice, effects not obtained with expression of p65 or a p65 delta mutant that contains a disruption within the transcriptional activation domain. Thus, p65 delta, which associated weakly and interfered with DNA binding by p65, may sequester an essential limiting regulatory factor or factors required for NF-kappa B function.

Comparison of 1H NMR chemical shifts of bovine and human insulins.

Two-dimensional NMR spectra have been recorded for bovine insulin at low pH in acetonitrile/water mixtures. In this solvent, insulin exists predominantly as the monomeric form. The spectra have been assigned and the 1H NMR chemical shifts compared with those for human insulin recorded in the same solvent system, with bovine insulin measured in trifluoroethanol/water, and with two human despentapeptide insulins. These comparisons were made to determine whether sequence or solvent differences have a significant effect on the solution structure of the monomer. It was found that the chemical shifts of the backbone protons for the bovine and human insulins were very similar in acetonitrile/water, suggesting that in this solvent mixture there is little difference in the solution structures of the two sequence variants. Similarly, for bovine insulin the chemical shifts in a trifluoroethanol/water solvent mixture are comparable to those observed in acetonitrile/water. This suggests that solvent induces only minor changes in the local conformation in solution. Most of the differences in chemical shifts in the various samples occurred away from the three helical regions seen in the x-ray crystallographic studies of the insulin structure. The observation of slowly exchanging amide resonances in both trifluoroethanol/water and acetonitrile/water solvent mixtures confirmed the existence of helical regions in solution. Exchange of amide resonances was slower in trifluoroethanol/water, suggesting greater stability for the B chain helix in this solvent.

Individual variability in tail tendon fiber break time in three age cohorts of different strains of mice.

Individual variability in mouse tail tendon fiber denaturation in urea was investigated. Differences in break time between fibers within tendons and between tendon groups were examined. Mean break times for each strain increased with age with the shorter-lived DBA/2 mice exhibiting higher break times within age cohorts than the C57BL/6 animals. Fibers from the two ventral tendon groups had consistently higher break times than those from the two dorsal groups, implying differential rates of collagen maturation between these two areas within the tail. Histological examination revealed conspicuous morphological dorsal/ventral differences in tendon number, proximity to a major blood vessel, and the amount of surrounding muscle tissue. These findings have methodological and experimental design implications for the use of tail tendon break time (TTBT) as a biomarker of aging. Furthermore, they suggest possible physiological mechanisms for differential rates of collagen aging.

2D 1H NMR studies of monomeric insulin.

In order to establish the conditions required for the observation of monomeric insulin in solution, a series of proton nuclear magnetic resonance studies of insulin in a variety of solvents was undertaken. Optimal spectra were recorded in trifluoroethanol- water mixtures in a 1:2 ratio. Using the sequential assignment approach the proton nuclear magnetic resonance spectrum of insulin was then assigned. Aspects of the structure of monomeric insulin in solution have been determined using the observed NOE cross peaks and slow exchange protons.

Cis-trans isomerization of the proline residue in insulin studied by 13C NMR spectroscopy.

The natural abundance 13C NMR spectrum of bovine insulin contains two resonances at 49.6 and 48.9 ppm which have a 7:3 intensity ratio at 298 K. Use of the DEPT spectral editing technique shows them to be of CH2 multiplicity. On the basis of their chemical shifts, which are well-resolved from other peaks, they are assigned as the C delta carbon of proline in trans and cis forms respectively. Since insulin contains only a single proline residue, the site of the isomerization can be localized at the peptide bond linking Thr-27 and Pro-28. On heating, the two peaks broaden, coalesce at 308 K, and then sharpen to yield a single peak at higher temperatures. The barrier for this process was calculated to be 64 kJ mol-1 (at the coalesce temperature), which is at the lower end of the range observed for proline isomerization in small peptides. Computer-graphic studies based on the X-ray crystal structure of insulin were used to deduce the structural implications of the cis-trans isomerism in this globular protein.

Injury to the ureter during gynecologic surgical procedures.

This retrospective study examined ureteral injuries during gynecologic operations from January 1980 to August 1985. The study was conducted at two private hospitals that are involved in resident teaching programs. Each patient was reviewed for predisposing factors, location and type of injury and time and method of recognition. Sixteen injuries were documented in 1,093 extensive procedures. Twelve injuries occurred at the pelvic brim and four others occurred elsewhere in the pelvis. Risk factors included previous surgical procedures in the pelvis, endometriosis, ovarian neoplasm, pelvic adhesions, distorted anatomic features of the pelvis and repair of the bladder. The anatomic structure of the ureter is reviewed, and recommendations are made to help prevent ureteral injury during surgical procedures in the pelvis.

C-13 NMR spectral studies of the thyroid hormone transport protein, transthyretin and the pancreatic insulin storage moiety, the zinc-insulin hexamer.

The DEPT spectral editing technique was used to separate the CH, CH2 and CH3 resonances in the C-13 NMR spectra of transthyretin and the porcine zinc insulin hexamer. The advantages of this technique in terms of spectral simplification and sensitivity enhancement for 13C NMR of proteins is discussed. Spin-lattice relaxation time and nuclear Overhauser effect measurements of the backbone C-alpha and aliphatic sidechain carbons provided information about the dynamics of the proteins in solution and the relative mobility of some sidechain groups.

Treatment of persistent trophoblastic tissue after salpingostomy with methotrexate.

Salpingostomy has become a common treatment of unruptured ectopic pregnancies. A complication of salpingostomy is persistent trophoblastic tissue. All reported cases to date of salpingostomy with persistent trophoblastic tissue have required salpingectomy. We reported a case of persistent trophoblastic tissue after salpingostomy treated successfully with methotrexate.