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Objective. Biomimetic protein-based artificial retinas offer a new paradigm for restoring vision for patients blinded by retinal degeneration. Artificial retinas, comprised of an ion-permeable membrane and alternating layers of bacteriorhodopsin (BR) and a polycation binder, are assembled using layer-by-layer electrostatic adsorption. Upon light absorption, the oriented BR layers generate a unidirectional proton gradient. The main objective of this investigation is to demonstrate the ability of the ion-mediated subretinal artificial retina to activate retinal ganglion cells (RGCs) of degenerated retinal tissue. Approach. Ex vivo extracellular recording experiments with P23H line 1 rats are used to measure the response of RGCs following selective stimulation of our artificial retina using a pulsed light source. Single-unit recording is used to evaluate the efficiency and latency of activation, while a multielectrode array (MEA) is used to assess the spatial sensitivity of the artificial retina films. Main results. The activation efficiency of the artificial retina increases with increased incident light intensity and demonstrates an activation latency of ∼150 ms. The results suggest that the implant is most efficient with 200 BR layers and can stimulate the retina using light intensities comparable to indoor ambient light. Results from using an MEA show that activation is limited to the targeted receptive field. Significance. The results of this study establish potential effectiveness of using an ion-mediated artificial retina to restore vision for those with degenerative retinal diseases, including retinitis pigmentosa.

Aromatase inhibitors (AIs) such as anastrozole, letrozole, and exemestane have shown to prevent metastasis and angiogenesis in estrogen receptor (ER)-positive breast and ovarian tumors. They function primarily by reducing estrogen production in ER-positive post-menopausal breast and ovarian cancer patients. Unfortunately, current AI-based therapies often have detrimental side-effects, along with acquired resistance, with increased cancer recurrence. Thus, there is an urgent need to identify novel AIs with fewer side effects and improved therapeutic efficacies. In this regard, we and others have recently suggested noncoding RNAs (ncRNAs), specifically microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), as potential molecular targets for utilization in modulating cancer hallmarks and overcoming drug resistance in several cancers, including ER-positive breast and ovarian cancer. Herein, we describe the disruptive functions of several miRNAs and lncRNAs seen in dysregulated cancer metabolism, with a focus on the gene encoding for aromatase (CYP19A1 gene) and estrogen synthesis as a novel therapeutic approach for treating ER-positive breast and ovarian cancers. Furthermore, we discuss the oncogenic and tumor-suppressive roles of several miRNAs (oncogenic miRNAs: MIR125b, MIR155, MIR221/222, MIR128, MIR2052HG, and MIR224; tumor-suppressive miRNAs: Lethal-7f, MIR27B, MIR378, and MIR98) and an oncogenic lncRNA (MIR2052HG) in aromatase-dependent cancers via transcriptional regulation of the CYP19A1 gene. Additionally, we discuss the potential effects of dysregulated miRNAs and lncRNAs on the regulation of critical oncogenic molecules, such as signal transducer, and activator of transcription 3, β-catenin, and integrins. The overall goal of this review is to stimulate further research in this area and to facilitate the development of ncRNA-based approaches for more efficacious treatments of ER-positive breast and ovarian cancer patients, with a slight emphasis on associated treatment–delivery mechanisms.

Buildings contribute 40% of global greenhouse gas emissions; therefore, strategies that can substantially reduce emissions from the building stock are key components of broader efforts to mitigate climate change and achieve sustainable development goals. Models that represent the energy use of the building stock at scale under various scenarios of technology deployment have become essential tools for the development and assessment of such strategies. Within the past decade, the capabilities of building stock energy models have improved considerably, while model transferability and sharing has increased. Given these advancements, a new scheme for classifying building stock energy models is needed to facilitate communication of modeling approaches and the handling of important model dimensions. In this article, we present a new building stock energy model classification framework that leverages international modeling expertise from the participants of the International Energy Agency's Annex 70 on Building Energy Epidemiology. Drawing from existing classification studies, we propose a multi-layer quadrant scheme that classifies modeling techniques by their design (top-down or bottom-up) and degree of transparency (black-box or white-box); hybrid techniques are also addressed. The quadrant scheme is unique from previous classification approaches in its non-hierarchical organization, coverage of and ability to incorporate emerging modeling techniques, and treatment of additional modeling dimensions. The new classification framework will be complemented by a reporting protocol and online registry of existing models as part of ongoing work in Annex 70 to increase the interpretability and utility of building stock energy models for energy policy making.

Vegetables of the Allium genus, such as garlic (Allium sativum L.), onions, shallots, leaks, and chives, have been used for many years for food consumption and for medicinal purposes. Historical medical texts have indicated the therapeutic applications of garlic as an antitumor, laxative, diuretic, antibacterial and antifungal agent. Specifically, garlic's antitumor abilities have been traced back 3500 years as a chemotherapeutic agent used in Egypt. Other beneficial effects of garlic consumption include lowering blood pressure, blood cholesterol, sugar and lipids. The processing and aging of garlic result in the production of non-toxic organosulfur by-products. These sulfur-containing compounds, such as allicin, diallyl sulfide, diallyl disulfide, diallyl trisulfide, alliin, S-allylcysteine, and S-allylmercaptocysteine, impact various stages of carcinogenesis. The anticancer mechanisms of action of these garlic-derived phytochemicals include altering mitochondrial permeability, inhibiting angiogenesis, enhancing antioxidative and proapoptotic properties, and regulating cell proliferation. All these effects of garlic's sulfur-compounds have been demonstrated in various human cancers. The intent of this literature research is to explore the potential of garlic-derived products and bioactive organosulfur compounds as cancer chemopreventive and chemotherapeutic agents. This investigation employs criteria for systematic review and critically analyzes published in vitro, in vivo and clinical studies. Concerns and limitations that have arisen in past studies regarding standards of measurement, bioavailability, and method of delivery are addressed. Overall, it is hoped that through this systematic and comprehensive review, future researchers can be acquainted with the updated data assembled on anticancer properties of garlic and its phytoconstituents.

The Working Group on the Analysis and Management of Accidents (WGAMA) was created on December 31st, 1999 to assess and strengthen the technical basis needed for the prevention, mitigation and management of potential accidents in NPP and to facilitate international convergence on safety issues and accident management analyses and strategies. WGAMA addresses reactor coolant system thermal-hydraulics, in-vessel behaviour of degraded cores and in-vessel protection, containment behaviour and containment protection, and fission product (FP) release, transport, deposition and retention, for both current and advanced reactors. As a result, WGAMA contributions in thermal-hydraulics, computational fluid-dynamics (CFD) and severe accidents along the first two decades of the 21st century have been outstanding and are summarized in this paper. Beyond any doubt, the Fukushima-Daiichi accident heavily impacted WGAMA activities and the substantial outcomes produced in the accident aftermath are neatly identified in the paper. Beyond specific events, most importantly, around 50 technical reports have become reference material in the different fields covered by the group and they are gathered altogether in the reference section of the paper; a common outstanding feature in most of these reports is the recommendations included for further research, some of which have eventually given rise to some of the projects conducted or underway within the OECD framework. Far from declining, ongoing WGAMA activities are numerous and a number of them is already planned to be launched in the near future; a short mention to them is also included in this paper.

Assignment of the protonation state of the residue Glu-181 is important to our understanding of the primary event, activation processes and wavelength selection in rhodopsin. Despite extensive study, there is no general agreement on the protonation state of this residue in the literature. Electronic assignment is complicated by the location of Glu-181 near the nodal point in the electrostatic charge shift that accompanies excitation of the chromophore into the low-lying, strongly allowed ππ* state. Thus, the charge on this residue is effectively hidden from electronic spectroscopy. This situation is resolved in bathorhodopsin, because photoisomerization of the chromophore places Glu-181 well within the region of negative charge shift following excitation. We demonstrate that Glu-181 is negatively charged in bathorhodopsin on the basis of the shift in the batho absorption maxima at 10 K [λ(max) band (native) = 544 ± 2 nm, λ(max) band (E181Q) = 556 ± 3 nm] and the decrease in the λ(max) band oscillator strength (0.069 ± 0.004) of E181Q relative to that of the native protein. Because the primary event in rhodopsin does not include a proton translocation or disruption of the hydrogen-bonding network within the binding pocket, we may conclude that the Glu-181 residue in rhodopsin is also charged.

The structures of a number of stereoisomers of carotenoids have been revealed in three-dimensional X-ray crystallographic investigations of pigment–protein complexes from photosynthetic organisms. Despite these structural elucidations, the reason for the presence of stereoisomers in these systems is not well understood. An important unresolved issue is whether the natural selection of geometric isomers of carotenoids in photosynthetic pigment–protein complexes is determined by the structure of the protein binding site or by the need for the organism to accomplish a specific physiological task. The association of cis isomers of a carotenoid with reaction centers and trans isomers of the same carotenoid with light-harvesting pigment–protein complexes has led to the hypothesis that the stereoisomers play distinctly different physiological roles. A systematic investigation of the photophysics and photochemistry of purified, stable geometric isomers of carotenoids is needed to understand if a relationship between stereochemistry and biological function exists. In this work we present a comparative study of the spectroscopy and excited state dynamics of cis and trans isomers of three different open-chain carotenoids in solution. The molecules are neurosporene (n = 9), spheroidene (n = 10), and spirilloxanthin (n = 13), where n is the number of conjugated π-electron double bonds. The spectroscopic experiments were carried out on geometric isomers of the carotenoids purified by high performance liquid chromatography (HPLC) and then frozen to 77 K to inhibit isomerization. The spectral data taken at 77 K provide a high resolution view of the spectroscopic differences between geometric isomers. The kinetic data reveal that the lifetime of the lowest excited singlet state of a cis-isomer is consistently shorter than that of its corresponding all-trans counterpart despite the fact that the excited state energy of the cis molecule is typically higher than that of the trans molecule. Quantum theoretical calculations on an n = 9 linear polyene were carried out to examine this process. The calculations indicate that the electronic coupling terms are significantly higher for the cis isomer, and when combined with the Franck–Condon factors, predict internal conversion rates roughly double those of the all-trans species. The electronic effects more than offset the decrease in coupling efficiencies associated with the higher system origin energies and explain the observed shorter cis isomer lifetimes.

Three active-site components in rhodopsin play a key role in the stability and function of the protein: 1) the counter-ion residues which stabilize the protonated Schiff base, 2) water molecules, and 3) the hydrogen-bonding network. The ionizable residue Glu-181, which is involved in an extended hydrogen-bonding network with Ser-186, Tyr-268, Tyr-192, and key water molecules within the active site of rhodopsin, has been shown to be involved in a complex counter-ion switch mechanism with Glu-113 during the photobleaching sequence of the protein. Herein, we examine the photobleaching sequence of the E181Q rhodopsin mutant by using cryogenic UV-visible spectroscopy to further elucidate the role of Glu-181 during photoactivation of the protein. We find that lower temperatures are required to trap the early photostationary states of the E181Q mutant compared to native rhodopsin. Additionally, a Blue Shifted Intermediate (BSI, λmax = 498 nm, 100 K) is observed after the formation of E181Q Bathorhodopsin (Batho, λmax = 556 nm, 10 K) but prior to formation of E181Q Lumirhodopsin (Lumi, λmax = 506 nm, 220 K). A potential energy diagram of the observed photointermediates suggests the E181Q Batho intermediate has an enthalpy value 7.99 KJ/mol higher than E181Q BSI, whereas in rhodopsin, the BSI is 10.02 KJ/mol higher in enthalpy than Batho. Thus, the Batho to BSI transition is enthalpically driven in E181Q and entropically driven in native rhodopsin. We conclude that the substitution of Glu-181 with Gln-181 results in a significant perturbation of the hydrogen-bonding network within the active site of rhodopsin. In addition, the removal of a key electrostatic interaction between the chromophore and the protein destabilizes the protein in both the dark state and Batho intermediate conformations while having a stabilizing effect on the BSI conformation. The observed destabilization upon this substitution further supports that Glu-181 is negatively charged in the early intermediates of the photobleaching sequence of rhodopsin.

Visual pigments have a conserved phenylalanine in transmembrane helix 5 located near the β-ionone ring of the retinal chromophore. Site-directed mutants of this residue (F207) in a short-wavelength sensitive visual pigment (VCOP) were studied using UV-visible spectroscopy to investigate its role in photosensitivity and formation of the light-activated state. The side chain is important for pigment formation: VCOP(F207A), VCOP(F207L), VCOP(F207M), and VCOP(F207W) substitutions all bound 11-cis-retinal and formed a stable visual pigment, while VCOP(F207V), VCOP(F207S), VCOP(F207T), and VCOP(F207Y) substitutions do not. The extinction coefficients of all pigments are close, ranging between 35800 and 45600 M⁻¹ cm⁻¹. Remarkably, the mutants exhibit an up to 5-fold reduction in photosensitivity and also abnormal photobleaching behavior. One mutant, VCOP(F207A), forms an isomeric composition of the retinal chromophore after illumination comparable to that of wild-type VCOP yet does not release the all-trans-retinal chromophore. These findings suggest that the conserved F207 residue is important for a normal photoactivation pathway, formation of the active conformation and the exit of all-trans-retinal from the chromophore-binding pocket.

The rational syntheses of meso-tetraaryl-3-oxo-2-oxaporphyrins 5, known as porpholactones, via MnO(4)(-)-mediated oxidations of the corresponding meso-tetraaryl-2,3-dihydroxychlorins (7) is detailed. Since chlorin 7 is prepared from the parent porphyrin 1, this amounts to a 2-step replacement of a pyrrole moiety in 1 by an oxazolone moiety. The stepwise reduction of the porpholactone 5 results in the formation of chlorin analogues, meso-tetraaryl-3-hydroxy-2-oxachlorin (11) and meso-tetraaryl-2-oxachlorins (12). The reactivity of 11 with respect to nucleophilic substitution by O-, N-, and S-nucleophiles is described. The profound photophysical consequences of the formal replacement of a pyrrole with an oxazolone (porphyrin-like chromophore) or (substituted) oxazole moiety (chlorin-like chromophore with, for the parent oxazolochlorin 12, red-shifted Q(x) band with enhanced oscillator strengths) are detailed and rationalized on the basis of SAC-CI and MNDO-PSDCI molecular orbital theory calculations. The single crystal X-ray structures of the porpholactones point at a minor steric interaction between the carbonyl oxygen and the flanking phenyl group. The essentially planar structures of all chromophores in all oxidation states prove that the observed optical properties originate from the intrinsic electronic properties of the chromophores and are not subject to conformational modulation.

From kinematics to molecular machines, biologically inspired technologies harness and enhance the intrinsic properties of naturally occurring materials and systems for applied technologies. Bacteriorhodopsin (BR) represents the most studied protein for photonic applications, and has found use in artificial retinas, associative and volumetric memories, optical limiters, photovoltaic cells and other devices. The native BR protein is rarely optimal for device applications, and genetic engineering plays an important role in the optimization process. In addition, new retinal proteins such as proteorhodopsin and channelrhodopsin-2 have been discovered which provide new options and opportunities.

Vision in vertebrates is a complex and involved process. Small organic molecules, known as chromophores, become electronically excited upon the absorption of a photon of light. In the excited state exists a barrier-less potential energy surface for some torsional movement about a double bond. The conformational change in the chromophore moiety induces a corresponding conformational change in the covalently bound polypeptide, thereby triggering a messenger cascade within the photoreceptor cell that results in the transmission of signals to the appropriate neurons. These signals are transmitted along the optic nerve to the visual centers of the brain, which allows the brain to process the visual input and perceive a visual image. The study of chromophores and photoreceptors in vitro is dominantly focused on theoretical computational calculations and spectroscopy. The focus of this chapter is to elucidate these methods, with emphasis on their application to the study of biological systems.

The role of the extracellular loop region of a short-wavelength sensitive pigment, Xenopus violet cone opsin, is investigated via computational modeling, mutagenesis, and spectroscopy. The computational models predict a complex H-bonding network that stabilizes and connects the EC2-EC3 loop and the N-terminus. Mutations that are predicted to disrupt the H-bonding network are shown to produce visual pigments that do not stably bind chromophore and exhibit properties of a misfolded protein. The potential role of a disulfide bond between two conserved Cys residues, Cys(105) in TM3 and Cys(182) in EC2, is necessary for proper folding and trafficking in VCOP. Lastly, certain residues in the EC2 loop are predicted to stabilize the formation of two antiparallel β-strands joined by a hairpin turn, which interact with the chromophore via H-bonding or van der Waals interactions. Mutations of conserved residues result in a decrease in the level of chromophore binding. These results demonstrate that the extracellular loops are crucial for the formation of this cone visual pigment. Moreover, there are significant differences in the structure and function of this region in VCOP compared to that in rhodopsin.

The structures of a number of stereoisomers of carotenoids have been revealed in three-dimensional X-ray crystallographic investigations of pigment-protein complexes from photosynthetic organisms. Despite these structural elucidations, the reason for the presence of stereoisomers in these systems is not well understood. An important unresolved issue is whether the natural selection of geometric isomers of carotenoids in photosynthetic pigment-protein complexes is determined by the structure of the protein binding site or by the need for the organism to accomplish a specific physiological task. The association of cis isomers of a carotenoid with reaction centers and trans isomers of the same carotenoid with light-harvesting pigment-protein complexes has led to the hypothesis that the stereoisomers play distinctly different physiological roles. A systematic investigation of the photophysics and photochemistry of purified, stable geometric isomers of carotenoids is needed to understand if a relationship between stereochemistry and biological function exists. In this work we present a comparative study of the spectroscopy and excited state dynamics of cis and trans isomers of three different open-chain carotenoids in solution. The molecules are neurosporene (n = 9), spheroidene (n = 10), and spirilloxanthin (n = 13), where n is the number of conjugated pi-electron double bonds. The spectroscopic experiments were carried out on geometric isomers of the carotenoids purified by high performance liquid chromatography (HPLC) and then frozen to 77 K to inhibit isomerization. The spectral data taken at 77 K provide a high resolution view of the spectroscopic differences between geometric isomers. The kinetic data reveal that the lifetime of the lowest excited singlet state of a cis-isomer is consistently shorter than that of its corresponding all-trans counterpart despite the fact that the excited state energy of the cis molecule is typically higher than that of the trans molecule. Quantum theoretical calculations on an n = 9 linear polyene were carried out to examine this process. The calculations indicate that the electronic coupling terms are significantly higher for the cis isomer, and when combined with the Franck-Condon factors, predict internal conversion rates roughly double those of the all-trans species. The electronic effects more than offset the decrease in coupling efficiencies associated with the higher system origin energies and explain the observed shorter cis isomer lifetimes.

The results of the therapy of 46 patients with glottic squamous cell cancer with a fixed vocal cord and without regional lymph nodes (glottic T3N0) are reported. Primary surgery (total laryngectomy) in combination with preoperative irradiation gave significantly higher loco-regional control rate and survival rate than surgery alone. Primary radiotherapy with doses of 70 Gy or more and adequate follow-up was found to be an alternative to preoperative radiation and laryngectomy. The result of different treatment modalities speaks in favour of primary irradiation allowing preservation of the larynx and a good voice function. In case of recurrence salvage surgery with total laryngectomy is preferred.

Fifty consecutive massively obese patients referred for gastroplasty operations were prospectively studied to determine the existence of gastroesophageal reflux disease by means of a standardized questionnaire, 24-hr ambulatory pH-metry, and endoscopy (27 females, mean age 48 years, range 38-57 years). These patients had a body mass index (BMI) of 42.5 +/- 5.2 kg/m2 and an actual weight of 125.5 +/- 17 kg. Heartburn and acid regurgitation was reported by 37% and 28%, respectively, mostly of a mild degree (22% and 20%). Dysphagia was reported by 2%, but none had odynophagia. No patient had any macroscopic esophagitis. The pH data were compared with those obtained in 29 age- and sex-matched, symptom-free, healthy controls (15 females, mean age 47.6 years, range 30-63 years). During ambulatory pH-metry, we recorded a predominance of daytime reflux (7.2 +/- 8.2% and total acid exposure of 5.3 +/- 6.4%) in the obese patients, but neither the weight, BMI, nor the waist-hip ratio were significantly correlated with any of the reflux variables. The pH data obtained from these patients did not, however, differ significantly from those recorded in the control population, although a somewhat lower daytime acid reflux was found in the latter group. These results suggest that massive overweight is not associated with an increased prevalence of gastroesophageal reflux disease.

Summary. The scintigraphic detection of small nocturnal aspirations of radio-labelled gastric contents is difficult in the presence of high remaining activity in the abdomen, causing a non-uniform background activity. This problem was examined in phantom experiments and a technique for interpolative background correction was further developed. The accuracy of this technique was found to be influenced by the distance between the lung and the abdominal source of activity, and the minimum detectable ‘aspirated’ activity was determined as 0.1 MBq at a distance of 15 cm and 1 MBq at 5 cm. The interpolative technique for background correction was evaluated on healthy volunteers and laryngectomized patients, examined 10 h after intragastric instillation of 200 MBq of 99Tcm-pertechnetate. After background subtraction, their calculated pulmonary mean net count value was comparable to that registered before the radioactive tracer was administered. No localized accumulation of activity was found in any of these controls. The technique was then applied clinically to 55 patients with chronic respiratory disorders and symptoms of gastroesophageal reflux. Aspiration was detected in 11 patients (20%). Five aspirators had asthma, two a chronic cough of unknown origin, two recurrent pulmonary infections, and one chronic bronchitis and chronic laryngitis respectively. Aspiration was detected among patients with and without demonstrated pathological gastroesophageal reflux.

A retrospective study has been made of 302 patients with vocal cord carcinoma stage I and II treated between 1963 and 1983, emphasizing treatment failure patterns. The primary treatment modalities were radiotherapy for 266 patients and surgery for 36 patients. The minimum follow-up was 4 years. After primary radiotherapy there were 63 local recurrences and 7 neck lymph node recurrences, all appearing outside the target volume. The actuarial loco-regional recurrence-free rates at 5 years were 78% for T1, 76% for T2a (normal cord mobility) and 60% for T2b (impaired cord mobility) tumors. The actuarial regional lymph node recurrence-free rates at 5 years were 99, 100 and 93% for T1, T2a and T2b tumors respectively. The actuarial corrected survivals at 5 years were 95, 96 and 79% for T1, T2a and T2b tumors with primary radiotherapy and salvage surgery for recurrence. Salvage surgery was less successful in T2b compared to T1 and T2a tumors. In conclusion, after primary radiotherapy with salvage surgery the loco-regional control rate was high and very similar for glottic cancer T1 and T2a but less satisfactory for T2b tumors. Regional lymph node metastases were not a large problem in any of the subgroups. More effective radiotherapy with higher dose levels or an altered fractionation might increase the local control rate for T2 tumors with impaired cord mobility.

A questionnaire study was conducted to assess the prevalence and severity of symptoms suggestive of esophageal disorders in a general population. The study included 407 randomly selected subjects, evenly distributed in terms of sex and age, within the age span of 20-79 years. A total of 337 subjects replied (85%). Symptoms suggestive of gastroesophageal reflux were found among 25% of the participants. Cough on swallowing was common (27%), as was globus (16%) and chest pain (13%). In addition, dysphagia was reported by 10% and vomiting by 9%. The symptoms were usually mild, and moderate to severe symptoms were reported only occasionally (1-4%). No statistical correlation was found between esophageal symptoms and age, sex, or the reported consumption of tobacco, alcohol, or non-steroidal anti-inflammatory drugs. The frequency of heartburn and/or acid regurgitation was twice as common among those with symptoms of respiratory disease as among those with no respiratory complaints. A stepwise logistic regression analysis showed that a chronic cough and/or breathing difficulties were significantly related to the presence of symptoms suggestive of gastroesophageal reflux.

High-Cr ferritic/martensitic steels are being considered as structural materials for a large number of future nuclear applications, from fusion to accelerator-driven systems and GenIV reactors. Fe-Cr alloys can be used as model materials to investigate some of the mechanisms governing their microstructure evolution under irradiation and its correlation to changes in their macroscopic properties. Focusing on these alloys, we show an example of how the integration of computer simulation and theoretical models can provide keys for the interpretation of a host of relevant experimental observations. In particular we show that proper accounting for two basic features of these alloys, namely, the existence of a fairly strong attractive interaction between self-interstitials and Cr atoms and of a mixing enthalpy that changes sign from negative to positive around 8 to 10 % Cr, is a necessary and, to a certain extent, sufficient condition to rationalize and understand their behavior under irradiation. These features have been revealed by ab initio calculations, are supported by experimental evidence, and have been adequately transferred into advanced empirical interatomic potentials, which have been and are being used for the simulation of damage production, defect behavior, and phase transformation in these alloys. The results of the simulations have been and are being used to parameterize models capable of extending the description of radiation effects to scales beyond the reach of molecular dynamics. The present paper intends to highlight the most important achievements and results of this research activity.

The effect of ara-A on cellular growth, DNA synthesis, and RNA synthesis, and RNA synthesis was measured in an established cell line (B-mix K-44/6) devoid of adenosine deaminase activity. Cells adapted to growth in a medium supplemented with horse serum provided an environment totally lacking adenosine deaminase activity whereas cultivation of cells in a medium supplemented with calf serum provided a system capable of deaminating ara-A to ara-H (half-life = 14 hours). Under deaminase-free conditions early log phase cells underwent 1.5 population doublings during 28 hours compared with 0.25 doublings in the presence of 37 micronM ara-A. When cells were grown in medium supplemented with calf serum the additionof 37 to 225 micronM ara-A resulted in a cessation of mitosis for periods of 5 to 30 hours respectively. Following this quiescent period growth resumed at the original rate. With 600 micronM ara-A mitosis was reversibly inhibited up to 35 hours after drug addition. The effects of ara-A on RNA and DNA synthesis were monitored by continuously or pulse labeling B-mix K-44/6 cells with [3H]-uridine or [3H]thymidine. Ara-A did not influence RNA synthesis as judged by labeled uridine incorporation. Under deaminase-free conditions, 5.4 micronM ara-A inhibited labeled thymidine incorporation by 50%. In the presence of the enzyme, approximately twice the ara-A concentration was required for the same inhibition; furthermore the initial inhibition was followed by a partial recovery in the rate of thymidine incorporation. Examination of thymidine incorporation. Examination of thymidine nucleotide pools during ara-A treatment revealed to changes in the labeling of dTMP, dTDP, and dTTP. Thus inhibition of [3H]thymidine incorporation by ara-A accurately reflected inhibition of DNA synthesis. We conclude that, in spite of an initial inhibition of DNA synthesis and mitosis by ara-A, B-mix K-44/6 cells recover from the inhibitory effects if the drug is removed either by a change in the culture medium or by metabolism to ara-H.

Studies were performed to test whether 9-/l-D-arabinofuranosyladenine (ara-A) would accumulate in erythrocytes as a result of phosphorylation to the nucleotide level. When C3H)ara-A was incubated with whole blood from rat, monkey or man for 2 hr at 37", the drug rapidly equilibrated between erythrocytes and plasma but did not concentrate in the cells. Incubation of C3H)ara-A with rat and human erythrocyte lysates for 2 hr followed by chromato~aphic analysis showed that 2-5 per cent of ara-A was converted to nucleo- tides. In contrast, 10-35 per cent of ('YY)adenosine was converted to adenine nucteotides under the same conditions. Incubation of C3H)ara-A with human erythrocyte lysates for 18 hr resulted in a conversion of approx. 40 per cent of the labeled drug to nucleotides. Ad- ditional chromatography revealed, however, that the nucleotide fraction contained almost no arabinosyl nucleotides. Rather, 90 per cent of the label in the nucleotide fraction was identified as IMP. These results indicate that only a minor amount, if any, of ara-A was phosphorylated by erythrocyte enzymes to yield arabinosyl nucleotides. An alternative pathway converted much of the labeled drug to ribosyl nucleotides via the deamination of ara-A to ara-hypoxanthine, cleavage to hypoxanthine and conversion of the free hypoxan- thine to IMP.

Ankylosis of the cricoarytenoid joints due to rheumatoid arthritis can cause severe laryngeal obstruction. With a mobilization and laterofixation procedure, five of six patients were successfully operated upon. Documented improvement of breathing was achieved and the voice function was acceptable after decannulation.

The indications for surgical procedures reducing gastric acid secretion in patients with hiatal hernia and symptomatic gastroesophageal reflux remain unclear. In a study of the postoperative results in 40 patients operated upon with modified Husfeldt hernia repair only, the results were assessed in relation to BAO and PAO. No correlation was found between the clinical results and BAO or PAO in patients in whom the reflux was successfully corrected by the procedure. It is concluded that gastric acid-reducing procedures are not indicated in patients in whom correction of reflux is anticipated.

Ankylosis of the cricoarytenoid joints due to rheumatoid arthritis (RA) may cause upper airway obstruction by fixation of the vocal cords in the midline. In early stages, this condition usually results in minor symptoms which are easily overlooked. It may, however, very rapidly, e.g., in association with an upper respiratory tract infection, become life-threatening. It is essential to diagnose this condition early to avoid emergency situations. In 5 patients with classic RA and in one patient with juvenile RA severe laryngeal obstruction was operated on using a new simple technique consisting of a mobilization of the arytenoid cartilages and laterofixation of one of the vocal cords.