Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Heritability estimates of atrial fibrillation in Thoroughbred racehorses in Hong Kong and Australia

INTRODUCTION

Atrial fibrillation (AF) is the most common performance-limiting arrhythmia of racehorses. A genetic contribution has been suggested in Standardbred racehorses but has not been investigated in Thoroughbreds. The objective of this study was to determine the heritability of AF in Thoroughbred racehorses.

ANIMALS, MATERIALS AND METHODS

Horses racing between 2007 and 2019 in Hong Kong and Australia that had AF detected postrace via auscultation (n = 463 cases) were compared with five randomly selected racing contemporaries (n = 2,315 controls). The ASReml-R programme was used to fit an animal model to the AF data to estimate heritability using the entire data set and a subset of horses (n = 106 cases) that had electrocardiographic confirmation of AF. Variance components were estimated assuming AF was normally distributed and on the logit-transformed scale. The risk of producing AF-affected offspring was calculated using Fisher's exact test for stallions that sired ≥10 individuals in the case-control population.

RESULTS

Heritability on the underlying scale was 0.064 ± 0.04 (logit animal) and 0.071 ± 0.04 (normal animal) for the entire population and 0.065 ± 0.097 (logit animal) and 0.058 ± 0.11 (normal animal) for electrocardiographic-confirmed AF cases. Of 71 stallions that sired ≥10 individuals, three were more likely to produce affected offspring (odds ratio: 4.05-7.57; p < 0.01). Age (p = 0.991), sex (p = 0.830), and year of birth (p = 0.547) did not contribute to expression.

CONCLUSIONS

Although some stallions were overrepresented amongst affected horses, the heritability of AF in this population of Thoroughbreds was low. Environmental and individual factors contributing to AF development require further investigation.

When infection isn't infection

Following open reduction and internal fixation for a proximal humerus fracture a 71-year-old man re-presented with wound changes consistent with infection and elevated inflammatory markers. No significant improvement was seen with concomitant intravenous antibiotics and multiple debridement procedures. This case was further complicated by soft tissue breakdown at the site of a left thigh haematoma also requiring debridement. Surgical site infections represent the most common cause of morbidity postoperatively. This case highlights the importance of considering a number of differential diagnoses. A diagnosis of pyoderma gangrenosum prompted systemic corticosteroid therapy giving rapid clinical improvement.

Complete upper airway collapse and apnoea during tethered swimming in horses

BACKGROUND

There is limited knowledge of the breathing strategy and impact on the patency of the upper respiratory tract (URT) in swimming horses.

OBJECTIVES

To describe the respiratory responses and endoscopic appearance of the URT during tethered swimming in horses.

STUDY DESIGN

Prospective descriptive study.

METHODS

Ten race-fit horses, with no history of URT obstruction, were examined during tethered swimming. Endoscopic examination, heart rate, sound recordings and above and below water video recordings were obtained. Plasma lactate concentration was measured before and 5 min after swimming and tracheal endoscopy was performed 30 min after exercise to assess for presence of blood or mucus. Four horses also underwent endoscopy during exercise on the track.

RESULTS

Mean (±s.d.) breathing frequency was 28 ± 5 breaths/min during swimming, with a brief inspiration (mean ± s.d. T_I  = 0.51 ± 0.08 s), followed by a period of apnoea (1.59 ± 0.53 s) and then a short, forced expiration (T_E  = 0.42 ± 0.5 s). During apnoea all horses exhibited complete collapse of the URT including closure of the external nares, nasopharynx and rima glottidis (with bilateral adduction of the arytenoid cartilages and vocal folds) and, in two horses, epiglottic retroversion. No horses had URT collapse during overground exercise. Locomotor-respiratory coupling was not observed during swimming. Median (IQR) plasma lactate post swim was 4.71 mmol/L (2.08-8.09 mmol/L) vs 0.68 mmol/L (0.65-0.71 mmol/L) preswim. Post swim endoscopy revealed grade 1 exercise-induced pulmonary haemorrhage (EIPH) in 2 horses. Median mucus grade was 1 (range 0-3).

MAIN LIMITATIONS

Overground endoscopy was not performed in all horses.

CONCLUSIONS

Horses experienced complete URT collapse associated with post inspiratory apnoea when swimming. The reason for this is unknown but may be to aid buoyancy or associated with the mammalian dive response - a survival reflex to preserve oxygen stores and prevent water entering the lungs.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

13-week dietary study and in vitro and in vivo genotoxicity studies of a structuring fat produced through a microalgal fermentation process

Microalgae are increasingly being utilized as food ingredients for a variety of applications, including as sources of protein, egg and dairy substitutes, and cooking oils. The dietary safety of a new structuring fat produced using a heterotrophic fermentation process by a strain of Prototheca moriformis was evaluated in a 13-week dietary toxicity study and compared with kokum fat, a structuring fat of similar composition used in the food industry and derived from Garcinia indica seeds. The algal structuring fat was evaluated for its genotoxic potential using both in vitro and in vivo assays. No treatment-related adverse events occurred in rats consuming algal structuring fat or kokum fat in the 13-week study; no treatment-related effects were reported for body weight, food consumption, urinalysis, hematology, clinical chemistry, gross pathology, organ weights, or histopathology. While statistically significant effects occurred in some parameters, none were dose-related or considered adverse. Overall, the NOAELs for the algal structuring fat and the kokum fat were 100 000 ppm, the highest concentrations tested. The algal structuring fat was not mutagenic in the bacterial reverse mutation assay in the Salmonella typhimurium or Escherichia coli strains tested and was not clastogenic in the in vivo mouse bone marrow chromosome aberration assay.

An in-vitro assessment of erosive potential of a calcium-fortified fruit juice

AIM

To evaluate and compare the in vitro pH, buffer capacity and calcium loss from tooth enamel before and after calcium fortification of a packaged fruit juice.

METHODS

An approved brand of packaged mixed fruit juice was selected as a test drink on the basis of a pilot questionnaire. The test drink was fortified with 1,000 mg/l (0.1% w/v) of calcium citrate malate to obtain two test groups: Group 1: original beverage (serving as control) and Group 2: calcium-fortified drink. The pH and buffering capacity for the test drinks were measured before and after calcium fortification; 90 prepared enamel samples were divided and immersed into three test subgroups: (1) buffer solution pH 7 (positive control), (2) original fruit juice (negative control) and (3) calcium-fortified fruit juice for 3 min. Calcium loss from the enamel of immersed teeth was measured as a quantitative estimate of tooth mineral loss.

RESULTS

After calcium fortification of the fruit juice the mean pH raised from 3.4 to 4.0 (p = 0.029), the mean buffer capacity decreased from 9.73 to 9.16 (p < 0.001) and the mean calcium loss from enamel specimens decreased from 3.5 to 0.26 mg/dl (p < 0.001).

STATISTICS

To compare the change in mean pH and buffering capacity between the subject groups, t test was used, and to compare the calcium loss from enamel specimens, among the three subgroups, ANOVA was used.

CONCLUSION

Calcium fortification of packaged fruit juice in vitro, improves its pH and buffering capacity. Consequently, the fortified juice causes significantly less mineral loss from human enamel. Fortifying juice with calcium may exert a significant protective potential against dental erosion particularly due to frequent exposure of acidic drinks.

Predictive markers for mammoplasty and a comparison of side effect profiles in transwomen taking various hormonal regimens

CONTEXT

Breast development in transwomen is an important issue, affecting general psychological functioning. Current hormonal therapies are imperfect, with 60% of patients requesting mammoplasty.

INTERVENTIONS

Interventions included the following: 1) comparing the effects on transwomen's requests for mammoplasty of estrogen valerate, ethinylestradiol, and conjugated equine estrogen (CEE) hormone treatments; and 2) comparing the effects of GnRH analogs and androgen antagonists.

OBJECTIVE

The objective of the study was to identify which hormone regimen is associated with the greatest subsequent request for augmentation mammoplasty.

DESIGN

The study was a controlled, retrospective case audit.

SETTING

The study was conducted at a single-center National Health Service tertiary care unit.

PATIENTS

Patients were eligible for breast augmentation after 2 yr of estrogen treatment, were Tanner IV or higher breast development, and reported psychological distress due to small breasts. One hundred sixty-five subjects and 165 age-matched controls were identified.

OUTCOME MEASURE

The outcome measure was a mammoplasty request.

RESULTS

There were significantly more self-medicating individuals than controls in the mammoplasty group (11.5 vs. 6%, P < 0.05). The type of estrogen use did not affect the outcome. Compared with other antiandrogens, spironolactone use was significantly higher in those requesting mammoplasty (4.8 vs. 1.8%, P = 0.002). Thromboembolism occurred in 1.2% of individuals, more frequently in those treated with CEE than in those treated with either estrogen valerate or ethinylestradiol (4.4 vs. 0.6 vs. 0.7%, P = 0.026). Depression was noted in approximately 30% of individuals.

CONCLUSIONS

Self-medication with estrogen is significantly more likely to result in a later request for mammoplasty than is treatment prescribed by licensed practitioners. Previous spironolactone use is more common in those requesting mammoplasty. CEE treatment is associated with a higher incidence of thromboembolism than treatment with other estrogen types.

1,5-Dimethyl-2-phenyl-4-[phenyl(pyri-din-2-ylamino)methyl]-1H-pyrazol-3(2H)-one

In the title compound, C(23)H(22)N(4)O, the pyrazole ring makes dihedral angles of 45.57 (11)° with the attached phenyl ring, and 83.98 (10) and 67.85 (10) °, respectively, with the other phenyl ring and the pyridyl ring. The pyridyl ring makes a dihedral angle of 80.15 (10)° with the adjacent phenyl ring. In the crystal, N-H⋯O hydrogen bonds supplemented by weak C-H⋯O hydrogen bonds link the mol-ecules into chains which run parallel to the a-axis direction.

The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes

The prevalence of germline mutations in MEN1, AIP, PRKAR1A, CDKN1B and CDKN2CI is unknown among pediatric patients with pituitary adenomas (PA). In this study, we screened children with PA for mutations in these genes; somatic GNAS mutations were also studied in a limited number of growth hormone (GH) or prolactin (PRL)-secreting PA. We studied 74 and 6 patients with either isolated Cushing disease (CD) or GH- or PRL-secreting PA, respectively. We also screened four pediatric patients with CD, and four with GH/PRL-secreting tumors who had some syndromic features. There was one AIP mutation (p.Lys103Arg) among 74 CD patients. Two MEN1 mutations that occurred in patients with recurrent or difficult-to-treat disease were found among patients with CD. There was one MEN1 and three AIP mutations (p.Gln307ProfsX104, p.Pro114fsX, p.Lys241X) among pediatric patients with isolated GH- or PRL-secreting PA and one additional MEN1 mutation in a patient with positive family history. There were no mutations in the PRKAR1A, CDKN1B, CDKN2C or GNAS genes. Thus, germline AIP or MEN1 gene mutations are frequent among pediatric patients with GH- or PRL-secreting PA but are significantly rarer in pediatric CD; PRKAR1A mutations are not present in PA outside of Carney complex.

Bis[2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidin-1-ium] DL-malate

Racemic malic acid and trimethoprim [5-(3,4,5-trimethoxybenzyl)pyrimidine-2,4-diamine] form a 1:2 salt (monoclinic, P2(1)/c), 2C(14)H(19)N(4)O(3)(+).C(4)H(4)O(5)(2-), in which the malate component is disordered across a centre of inversion. The crystal structure of the salt consists of protonated trimethoprim residues and a malate dianion. The carboxylate group of the malate ion interacts with the trimethoprim cation in a linear fashion through pairs of N-H...O hydrogen bonds to form a cyclic hydrogen-bonded motif. This is similar to the carboxylate-trimethoprim cation interaction observed earlier in the complex of dihydrofolate reductase with trimethoprim. The structure of the salt of trimethoprim with racemic DL-malic acid reported here is the first of its kind. The present study investigates the conformations and the hydrogen-bonding interactions, which are very important for biological functions. The pyrimidine plane makes a dihedral angle of 78.08 (7) degrees with the benzene ring of the trimethoprim cation. The cyclic hydrogen-bonded motif observed in this structure is self-organized, leading to novel types of hydrogen-bonding motifs in supramolecular patterns.

4,4'-Dimethoxy-benzophenone: a triclinic polymorph

The title compound, C(15)H(14)O(3), has been found to crystallize as a new triclinic polymorph. The asymmetric unit of the present structure, as in the previously reported monoclinic structure [Norment & Karle (1962 ▶). Acta Cryst. 15, 873-878], contains two independent mol-ecules, which differ slightly in the orientations of the two benzene rings. The crystal packing of the triclinic polymorph is stabilized by inter-molecular C-H⋯O hydrogen bonds and C-H⋯π inter-actions.

2-Amino-pyridinium (2-amino-pyridine)trichloridonickelate(II)

In the title compound, (C(5)H(7)N(2))[NiCl(3)(C(5)H(6)N(2))], the Ni(II) atom is four-coordinated by three chloride anions and one N atom of a 2-amino-pyridine ligand, forming a distorted tetra-hedral coordination. In the crystal structure, cations and complex anions are linked into chains along the a, b and c axes by N-H⋯Cl hydrogen bonds, leading to the formation of a three-dimensional framework.

Preparative electrophoresis: a general method for the purification of polyclonal antibodies

Antibodies were purified from normal rabbit, sheep, goat, rat, human and bovine serum using preparative electrophoresis on a Gradiflow in a single-step process using an asymmetrical cartridge with three different pore size polyacrylamide membranes. Recoveries in each case were over 80% and were higher than those obtained using affinity chromatography on protein A, protein G or protein L. Degree of purity was at least comparable with these methods. These results suggest that preparative electrophoresis can be considered a general method for the purification of research quantities of antibodies from multiple serum sources and may be particularly useful where the reactivity with protein A, G or L is unknown.

An investigation of the interaction between thematic and phrasal structure in nonfluent agrammatic subjects

Garrett (1982) developed a model of normal sentence production which has been used in the description of aphasic language (Schwartz, 1987). This study investigated the effects of the thematic representation specified at the functional level on the complexity of the phrases produced at the positional level. A group of 14 nonfluent, agrammatic subjects were compared to 20 normal controls in their production of the story of Cinderella. The agrammatic subjects produced fewer argument structures than the normal control subjects. Their phrasal realization of the arguments, however, was not qualitatively different from that of the normal subjects. In both cases, with an increase in the number of arguments, there was a concurrent increase in the mean complexity of the phrases used to realize those arguments and in the total phrasal complexity of the utterances. The complexity of noun phrases differed according to the thematic roles expressed; this seemed to be a consequence of their different locations in the sentence. Preverbal noun phrases were much less complex than postverbal noun phrases. There was no evidence to suggest that there was a trade-off between the production of thematic structure and subsequent phrasal production. Neither was there evidence to suggest that production differed according to whether the phrase was an argument of the verb or a nonargument. The complexity of a phrase was determined by the type of information it conveyed.

Noun-verb differences? a question of semantics: a response to shapiro and caramazza

We presented a new model using the sensory/functional theory of semantic category deficits to explain noun/verb deficits in aphasia. The predictions arising from this model were tested on a small number of patients exhibiting grammatical and/or semantic category specific deficits in picture naming. The results lent support for the theory presented. Shapiro and Caramazza (this issue) raised several objections to this theory (which they call the "extended sensory functional theory," or ESFT). In this article we address their concerns about the validity of the ESFT and conclude that it is indeed a useful model that provides a parsimonious explanation for many diverse patterns of deficits.

Age of acquisition and imageability ratings for a large set of words, including verbs and function words

Age of acquisition and imageability ratings were collected for 2,645 words, including 892 verbs and 213 function words. Words that were ambiguous as to grammatical category were disambiguated: Verbs were shown in their infinitival form, and nouns (where appropriate) were preceded by the indefinite article (such as to crack and a crack). Subjects were speakers of British English selected from a wide age range, so that differences in the responses across age groups could be compared. Within the subset of early acquired noun/verb homonyms, the verb forms were rated as later acquired than the nouns, and the verb homonyms of high-imageability nouns were rated as significantly less imageable than their noun counterparts. A small number of words received significantly earlier or later age of acquisition ratings when the 20-40 years and 50-80 years age groups were compared. These tend to comprise words that have come to be used more frequently in recent years (either through technological advances or social change), or those that have fallen out of common usage. Regression analyses showed that although word length, familiarity, and concreteness make independent contributions to the age of acquisition measure, frequency and imageability are the most important predictors of rated age of acquisition.

Determination of erythromycin and related substances in enteric-coated tablet formulations by reversed-phase liquid chromatography

An isocratic method for the identification and quantitation of erythromycin and related substances in enteric-coated tablet formulations using high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection at 205 nm is described. A novel method for sample preparation using a molecular weight centrifuge filter to reduce the interferences observed from polymeric tablet coating material is also presented. Erythromycin HPLC assays are best run at high pH; therefore, various polymer columns were evaluated. The resulting HPLC method that was developed has several advantages over current pharmacopeial assay methods for enteric-coated erythromycin tablets. Comparative data from both methods for the same batch of EryTab tablets are presented. The method can also be applied to various other erythromycin formulations, including particle-coated tablets, erythromycin stearate tablets, and erythromycin ethylsuccinate suspensions and fermentation broths. A C18 Polymeric column is used with a mobile phase composition of 0.02 M potassium phosphate dibasic buffer (pH 9): acetonitrile (60:40) and flow rate of 1 mL/min. This method is more sensitive, specific, and rugged than the pharmacopeial method.

Why is a verb like an inanimate object? Grammatical category and semantic category deficits

Semantic category effects, such as difficulties in naming animate things relative to inanimate objects, have been explained in terms of the relative weightings of perceptual and functional features within the semantic representations of these concepts. We argue that grammatical category deficits, such as difficulties in naming nouns relative to verbs, can be explained within the same framework. We hypothesize that verb concepts are richer in functional than sensory features and present a model of the semantic representations of animate nouns, inanimate nouns, and verbs. The model demonstrates that sensory feature damage results in a deficit for naming living things but spares verb naming, and functional feature damage results in a deficit for naming inanimate objects and verbs. We then report the assessment results of two patient groups. In accordance with the model's predictions, the "verb spared" patients were consistently worse at naming living things than inanimate objects, and their definitions of both living and nonliving items were lacking in sensory information. We conclude that damage to sensory features in semantic representations causes difficulties in naming concrete nouns relative to action verbs, and within the grammatical category of nouns, animate items will be more severely affected. Imageability was shown to be a strong predictor of naming performance in the "verb deficit" patients, and when this variable was controlled no class effect remained. Production of definitions revealed no differential damage to sensory or functional features, and no consistent effect of animacy in naming was shown. While the model suggests that verb deficits might occur in patients for whom functional features are damaged relative to sensory features, we conclude that the "verb deficit" shown in our patients (and potentially in many previously reported cases) was an artifact of the lower imageability of verbs in confrontation naming tasks.

Reboxetine: a pharmacologically potent, selective, and specific norepinephrine reuptake inhibitor

BACKGROUND

Reboxetine is a potent antidepressant, with efficacy comparable to that of imipramine, desipramine, and fluoxetine, and has improved side-effect profile. The basis of its efficacy and improved tolerability is sought through studies of reboxetine in a number of pharmacological models of depression.

METHODS

Pharmacological selectivity for uptake systems was defined by uptake and binding assays for the three monoamine uptake sites. Specificity was determined in 39 different receptor and 6 enzyme assays. In vivo selectivity was defined by measurement of neuronal firing rates in the locus coeruleus, dorsal raphe, and substantia nigra. Reserpine-induced blepharospasm and hypothermia, clonidine-induced hypothermia, defined reboxetine's in vivo pharmacology. Reboxetine's antidepressant potential was evaluated behaviorally by the tail-suspension test, forced swimming, and the DRL72 operant responding test.

RESULTS

Reboxetine is a potent, selective, and specific norepinephrine reuptake inhibitor (selective NRI) as determined by both in vitro and in vivo measurements. Unlike desipramine or imipramine, reboxetine has weak affinity (Ki > 1,000 nmol/L)for muscarinic, histaminergic H1, adrenergic alpha1, and dopaminergic D2 receptors. In vivo action of reboxetine is entirely consistent with the pharmacological action of an antidepressant with preferential action at the norepinephrine reuptake site. Reboxetine showed an antidepressant profile in all tests of antidepressant activity used. Significant decreases in immobility were observed in the tail suspension test and behavioral despair test. Increased efficiency in responding was observed in the DRL72 test.

CONCLUSIONS

Reboxetine is a potent, selective, and specific noradrenergic reuptake inhibitor. It has a superior pharmacological selectivity to existing tricyclic antidepressants and selective serotonin reuptake inhibitors when tested in a large number of in vitro and in vivo systems. Given the pharmacological profile, reboxetine is expected to be a selective and potent tool for psychopharmacological research. The use of reboxetine in the clinic will also help clarify the role norepinephrine plays in depression.

A software agent model of consciousness

Baars (1988, 1997) has proposed a psychological theory of consciousness, called global workspace theory. The present study describes a software agent implementation of that theory, called "Conscious" Mattie (CMattie). CMattie operates in a clerical domain from within a UNIX operating system, sending messages and interpreting messages in natural language that organize seminars at a university. CMattie fleshes out global workspace theory with a detailed computational model that integrates contemporary architectures in cognitive science and artificial intelligence. Baars (1997) lists the psychological "facts that any complete theory of consciousness must explain" in his appendix to In the Theater of Consciousness; global workspace theory was designed to explain these "facts." The present article discusses how the design of CMattie accounts for these facts and thereby the extent to which it implements global workspace theory.

Analysis of surgical margins with the molecular marker eIF4E: a prognostic factor in patients with head and neck cancer

PURPOSE

Complete excision of cancer is guided by histologic assessment of surgical margins. Molecular markers may be more sensitive in identifying malignant cells. eIF4E, a eukaryotic protein synthesis initiation factor, is found elevated in all head and neck squamous cell cancers (HNSCC). In a preliminary study using Western blots and a retrospective study using immunohistochemistry, eIF4E elevation in histologically tumor-free surgical margins correlated with a higher local-regional recurrence. We wanted to confirm this hypothesis in a prospective study.

PATIENTS AND METHODS

Immunohistochemical analysis of surgical margins and tumors with an antibody to eIF4E was performed on all newly diagnosed HNSCC patients who underwent surgical resection for their disease between January 1996 and December 1997.

RESULTS

All 65 patients had elevated levels of eIF4E in the tumors. Thirty-six patients (55%) had elevated eIF4E in histologically tumor-free margins, and 20 of these patients (56%) have had local-regional recu rrences. Twenty-nine patients (45%) had no elevation of eIF4E in the margins, and only two of these patients (6.9%) have had recurrences. Cox regression analysis showed that elevated eIF4E in the margins was an independent prognostic factor (P =.009) for recurrence. The Kaplan-Meier curves for the probability of nonrecurrence were significantly different for positive and negative eIF4E margins (P =. 0001, log-rank test).

CONCLUSION

In histologically tumor-free surgical margins, elevated levels of eIF4E predict a significantly increased risk of recurrence. Elevated levels of eIF4E in tumor margins may identify patients who could benefit from additional therapy.

Expression of eIF4E during head and neck tumorigenesis: possible role in angiogenesis

OBJECTIVE

The translation initiation factor eIF4E (4E) when overexpressed in mammalian cells results in their oncogenic transformation. 4E facilitates the synthesis of two powerful tumor angiogenic factors (VEGF and FGF-2) by selectively enhancing their translation. 4E is overexpressed not only in all head and neck squamous cell cancers but also in some dysplastic margins. Tumorigenesis in the head and neck is proposed to be a multistep process preceded by clinically evident precancerous lesions. Molecular events underlie the histological changes that herald transformation. We wanted to study the role of 4E in tumorigenesis and further elucidate its causal role in angiogenesis.

METHODS

An immunohistochemical analysis with antibodies to 4E, VEGF, and basic (b)-FGF was performed on 115 specimens of the head and neck representing various stages of histological progression of malignancy. This was correlated with mean vessel density (MVD) using factor VIII.

RESULTS

There were 41 cases of hyperplasia and low-grade dysplasia, 40 cases of high-grade dysplasia and 34 cases of cancer. There was a significant increase in the percent of cases expressing 4E from low-grade dysplasia through tumor. However, for VEGF and b-FGF the significant increase was only seen between the tumor group and dysplastic groups and no significant increase was noted between low-grade and high-grade dysplasia There was a significant increase in MVD from low- (10.7+/-1) to high-grade grade dysplasia (18.0+/-2.3). This increase was even more striking for the 4E positive cases.

CONCLUSION

4E elevation is correlated with progressive cell transformation in the head and neck. Its correlation with VEGF, b-FGF, and MVD potentiates its possible role in angiogenesis.