Mechanism of Ψ-Pro/C-degron recognition by the CRL2FEM1B ubiquitin ligase

The E3 ligase-degron interaction determines the specificity of the ubiquitin‒proteasome system. We recently discovered that FEM1B, a substrate receptor of Cullin 2-RING ligase (CRL2), recognizes C-degrons containing a C-terminal proline. By solving several cryo-EM structures of CRL2FEM1B bound to different C-degrons, we elucidate the dimeric assembly of the complex. Furthermore, we reveal distinct dimerization states of unmodified and neddylated CRL2FEM1B to uncover the NEDD8-mediated activation mechanism of CRL2FEM1B. Our research also indicates that, FEM1B utilizes a bipartite mechanism to recognize both the C-terminal proline and an upstream aromatic residue within the substrate. These structural findings, complemented by in vitro ubiquitination and in vivo cell-based assays, demonstrate that CRL2FEM1B-mediated polyubiquitination and subsequent protein turnover depend on both FEM1B-degron interactions and the dimerization state of the E3 ligase complex. Overall, this study deepens our molecular understanding of how Cullin-RING E3 ligase substrate selection mediates protein turnover.

Molecular basis for C-degron recognition by CRL2APPBP2 ubiquitin ligase

E3 ubiquitin ligases determine the specificity of eukaryotic protein degradation by selective binding to destabilizing protein motifs, termed degrons, in substrates for ubiquitin-mediated proteolysis. The exposed C-terminal residues of proteins can act as C-degrons that are recognized by distinct substrate receptors (SRs) as part of dedicated cullin-RING E3 ubiquitin ligase (CRL) complexes. APPBP2, an SR of Cullin 2-RING ligase (CRL2), has been shown to recognize R-x-x-G/C-degron; however, the molecular mechanism of recognition remains elusive. By solving several cryogenic electron microscopy structures of active CRL2APPBP2 bound with different R-x-x-G/C-degrons, we unveiled the molecular mechanisms underlying the assembly of the CRL2APPBP2 dimer and tetramer, as well as C-degron recognition. The structural study, complemented by binding experiments and cell-based assays, demonstrates that APPBP2 specifically recognizes the R-x-x-G/C-degron via a bipartite mechanism; arginine and glycine, which play critical roles in C-degron recognition, accommodate distinct pockets that are spaced by two residues. In addition, the binding pocket is deep enough to enable the interaction of APPBP2 with the motif placed at or up to three residues upstream of the C-end. Overall, our study not only provides structural insight into CRL2APPBP2-mediated protein turnover but also serves as the basis for future structure-based chemical probe design.

Defining E3 ligase-substrate relationships through multiplex CRISPR screening

Specificity within the ubiquitin-proteasome system is primarily achieved through E3 ubiquitin ligases, but for many E3s their substrates-and in particular the molecular features (degrons) that they recognize-remain largely unknown. Current approaches for assigning E3s to their cognate substrates are tedious and low throughput. Here we developed a multiplex CRISPR screening platform to assign E3 ligases to their cognate substrates at scale. A proof-of-principle multiplex screen successfully performed ~100 CRISPR screens in a single experiment, refining known C-degron pathways and identifying an additional pathway through which Cul2FEM1B targets C-terminal proline. Further, by identifying substrates for Cul1FBXO38, Cul2APPBP2, Cul3GAN, Cul3KLHL8, Cul3KLHL9/13 and Cul3KLHL15, we demonstrate that the approach is compatible with pools of full-length protein substrates of varying stabilities and, when combined with site-saturation mutagenesis, can assign E3 ligases to their cognate degron motifs. Thus, multiplex CRISPR screening will accelerate our understanding of how specificity is achieved within the ubiquitin-proteasome system.

Ubiquitin-independent proteasomal degradation driven by C-degron pathways

Although most eukaryotic proteins are targeted for proteasomal degradation by ubiquitination, a subset have been demonstrated to undergo ubiquitin-independent proteasomal degradation (UbInPD). However, little is known about the molecular mechanisms driving UbInPD and the degrons involved. Utilizing the GPS-peptidome approach, a systematic method for degron discovery, we found thousands of sequences that promote UbInPD; thus, UbInPD is more prevalent than currently appreciated. Furthermore, mutagenesis experiments revealed specific C-terminal degrons required for UbInPD. Stability profiling of a genome-wide collection of human open reading frames identified 69 full-length proteins subject to UbInPD. These included REC8 and CDCA4, proteins which control proliferation and survival, as well as mislocalized secretory proteins, suggesting that UbInPD performs both regulatory and protein quality control functions. In the context of full-length proteins, C termini also play a role in promoting UbInPD. Finally, we found that Ubiquilin family proteins mediate the proteasomal targeting of a subset of UbInPD substrates.

Meet the author: Itay Koren

Itay Koren, lead contact of the Resource "Ubiquitin-independent proteasomal degradation driven by C-degron pathways," discusses his unexpected career path to becoming a scientist, the people who inspired him along the way, and his mentorship style.

The hidden (degron) truth behind the degradation of DHFR disease-associated variants

In this issue of Structure, Kampmeyer et al. provide detailed mechanistic insights into how structural changes in disease-associated dihydrofolate reductase (DHFR) missense variants affect their cellular protein abundance and discuss implications for hereditary megaloblastic anemia disease.

Molecular basis for arginine C-terminal degron recognition by Cul2FEM1 E3 ligase

Degrons are elements within protein substrates that mediate the interaction with specific degradation machineries to control proteolysis. Recently, a few classes of C-terminal degrons (C-degrons) that are recognized by dedicated cullin-RING ligases (CRLs) have been identified. Specifically, CRL2 using the related substrate adapters FEM1A/B/C was found to recognize C degrons ending with arginine (Arg/C-degron). Here, we uncover the molecular mechanism of Arg/C-degron recognition by solving a subset of structures of FEM1 proteins in complex with Arg/C-degron-bearing substrates. Our structural research, complemented by binding assays and global protein stability (GPS) analyses, demonstrates that FEM1A/C and FEM1B selectively target distinct classes of Arg/C-degrons. Overall, our study not only sheds light on the molecular mechanism underlying Arg/C-degron recognition for precise control of substrate turnover, but also provides valuable information for development of chemical probes for selectively regulating proteostasis.

A glycine-specific N-degron pathway mediates the quality control of protein N-myristoylation

The N-terminal residue influences protein stability through N-degron pathways. We used stability profiling of the human N-terminome to uncover multiple additional features of N-degron pathways. In addition to uncovering extended specificities of UBR E3 ligases, we characterized two related Cullin-RING E3 ligase complexes, Cul2^ZYG11B and Cul2^ZER1, that act redundantly to target N-terminal glycine. N-terminal glycine degrons are depleted at native N-termini but strongly enriched at caspase cleavage sites, suggesting roles for the substrate adaptors ZYG11B and ZER1 in protein degradation during apoptosis. Furthermore, ZYG11B and ZER1 were found to participate in the quality control of N-myristoylated proteins, in which N-terminal glycine degrons are conditionally exposed after a failure of N-myristoylation. Thus, an additional N-degron pathway specific for glycine regulates the stability of metazoan proteomes.

The Eukaryotic Proteome Is Shaped by E3 Ubiquitin Ligases Targeting C-Terminal Degrons

Degrons are minimal elements that mediate the interaction of proteins with degradation machineries to promote proteolysis. Despite their central role in proteostasis, the number of known degrons remains small, and a facile technology to characterize them is lacking. Using a strategy combining global protein stability (GPS) profiling with a synthetic human peptidome, we identify thousands of peptides containing degron activity. Employing CRISPR screening, we establish that the stability of many proteins is regulated through degrons located at their C terminus. We characterize eight Cullin-RING E3 ubiquitin ligase (CRL) complex adaptors that regulate C-terminal degrons, including six CRL2 and two CRL4 complexes, and computationally implicate multiple non-CRLs in end recognition. Proteome analysis revealed that the C termini of eukaryotic proteins are depleted for C-terminal degrons, suggesting an E3-ligase-dependent modulation of proteome composition. Thus, we propose that a series of "C-end rules" operate to govern protein stability and shape the eukaryotic proteome.

A model-driven methodology for exploring complex disease comorbidities applied to autism spectrum disorder and inflammatory bowel disease

We propose a model-driven methodology aimed to shed light on complex disorders. Our approach enables exploring shared etiologies of comorbid diseases at the molecular pathway level. The method, Comparative Comorbidities Simulation (CCS), uses stochastic Petri net simulation for examining the phenotypic effects of perturbation of a network known to be involved in comorbidities to predict new roles for mutations in comorbid conditions. To demonstrate the utility of our novel methodology, we investigated the molecular convergence of autism spectrum disorder (ASD) and inflammatory bowel disease (IBD) on the autophagy pathway. In addition to validation by domain experts, we used formal analyses to demonstrate the model's self-consistency. We then used CCS to compare the effects of loss of function (LoF) mutations previously implicated in either ASD or IBD on the autophagy pathway. CCS identified similar dynamic consequences of these mutations in the autophagy pathway. Our method suggests that two LoF mutations previously implicated in IBD may contribute to ASD, and one ASD-implicated LoF mutation may play a role in IBD. Future targeted genomic or functional studies could be designed to directly test these predictions.

[One stage combined endoscopic and per-oral buccal fat pad approach for large oro-antral-fistula closure with secondary chronic maxillary sinusitis]

There are numerous surgical approaches for oro-antral-fistula (OAF) closure. Secondary sinus disease is still considered by many experts a relative contra indication for primary closure. To describe a single-stage combined endoscopic sinus surgery and per-oral buccal fat pad (BFP) flap approach for large OAF causing chronic maxillary sinusitis. The records of all the patients with OAF and chronic manifestations of secondary rhinosinusitis that were treated between 2010 and 2013 in our tertiary care medical center were reviewed. The exclusion criteria were: OAF 5 mm, resolved sino-nasal disease, OAF secondary to malignancy, recurrent fistula, medical history that included radiotherapy to the maxillary bone and age <18 years. Each procedure was performed by a team consisting of a rhinologist and a maxillofacial surgeon. The surgical approach included an endoscopic middle antrostomy with maxillary sinus drainage, and a per-oral BFP regional flap for OAF closure. Total OAF closure, complications and need for revision surgeries. Forty-five patients that underwent OAF closure together with sinus surgery using a combined endoscopic sinus surgery (ESS) and BFP flap approach met the inclusion criteria. There were 28 males and 17 females with a mean ± SD age of 53.5 ± 14.9 years (range 22-80 years). The presenting signs and symptoms included purulent rhinorrhea (n = 22, 48.9%), foreign body in sinus (n = 10, 22.2%) nasal congestion (n = 7, 15.5%), halitosis (n = 6, 13.3%) and pain (n = 5, 12.2%). Surgical complications included local pain (n = 2, 4.4%), persistent rhinitis (n = 2, 4.4%) and synechia (n = 1, 2.2%). One patient required revision surgery due, to an unresolved OAF. The OAF of all the other 44 patients (97.8%) was closed after the first procedure and the paranasal sinuses on the treated side were completely recovered. The mean follow-up time for the group was 7.6 ± 4.3 months (7-21 months), and no untoward sequelae or recurrence were reported. Combined, one step, endoscopic Maxillary sinus drainage together with per-oral BFP flap approach is an efficacious surgical approach for safe closure of OAFs that are complicated with secondary chronic maxillary sinusitis.

Quantitative Proteomic Atlas of Ubiquitination and Acetylation in the DNA Damage Response

Execution of the DNA damage response (DDR) relies upon a dynamic array of protein modifications. Using quantitative proteomics, we have globally profiled ubiquitination, acetylation, and phosphorylation in response to UV and ionizing radiation. To improve acetylation site profiling, we developed the strategy FACET-IP. Our datasets of 33,500 ubiquitination and 16,740 acetylation sites provide valuable insight into DDR remodeling of the proteome. We find that K6- and K33-linked polyubiquitination undergo bulk increases in response to DNA damage, raising the possibility that these linkages are largely dedicated to DDR function. We also show that Cullin-RING ligases mediate 10% of DNA damage-induced ubiquitination events and that EXO1 is an SCF-Cyclin F substrate in the response to UV radiation. Our extensive datasets uncover additional regulated sites on known DDR players such as PCNA and identify previously unknown DDR targets such as CENPs, underscoring the broad impact of the DDR on cellular physiology.

Androgen Receptor CAG Repeat Length in Relation to Phenotype Among Females with Nonclassical 21-Hydroxylase Deficiency

Nonclassical 21-hydroxylase deficiency (NC21OHD) manifests with various degrees of post natal virilization. The length of CAG repeats of the androgen receptor gene (AR) is inversely correlated to activity of the human androgen receptor (AR) and affects phenotype of several androgen-dependent disorders. The aim of the study was to investigate the associations between CAG repeat length and the phenotype of females with NC21OHD. CAG repeat length and AR inactivation were assessed in females with NC21OHD, and related to their clinical presentation. CAG repeat length and AR inactivation were assessed in 119 females with NC21OHD. Biallelic mean (BAM) of the CAG repeat length and the weighted BAM (WBAM) were related to various clinical parameters. Age at diagnosis and age of menarche positively correlated with BAM (r=0.22, p=0.02, and r=0.23, p=0.01, respectively). A shorter (<25) BAM was associated with younger age at diagnosis (14.8 vs. 21.4 years, p<0.01), at adrenarche (8.1 vs. 10.2 years, p<0.01) and gonadarche (9.9 vs. 11.2 years, p<0.01), and higher corrected height standard deviation score at diagnosis (0.77 vs. 0.15, p=0.01). Precocious pubarche and precocious puberty were more frequent in these with the shorter BAM. Results of WBAM were similar. The CAG repeat length of the AR gene contributes to the clinical diversity of the phenotype in females with NC21OHD.

An examination of retention factors among registered practical nurses in north-eastern Ontario, Canada

INTRODUCTION

Literature from the past two decades has presented an insufficient amount of research conducted on the nursing practice environments of registered practical nurses (RPNs). The objective of this article was to investigate the barriers and facilitators to sustaining the nursing workforce in north-eastern Ontario (NEO), Canada. In particular, retention factors for RPNs were examined.

METHODS

This cross-sectional research used a self-administered questionnaire. Home addresses of RPNs working in NEO were obtained from the College of Nurses of Ontario (CNO). Following a modified Dillman approach with two mail-outs, survey packages were sent to a random sample of RPNs (N=1337) within the NEO region. Logistic regression analyses were used to determine intent to stay (ITS) in relation to the following factor categories: demographic, and job and career satisfaction.

RESULTS

Completed questionnaires were received from 506 respondents (37.8% response rate). The likeliness of ITS in the RPNs' current position for the next 5 years among nurses aged 46-56 years were greater than RPNs in the other age groups. Furthermore, the lifestyle of NEO, internal staff development, working in nursing for 14-22.5 years, and working less than 1 hour of overtime per week were factors associated with the intention to stay.

CONCLUSIONS

Having an understanding of the work environment may contribute to recruitment and retention strategy development. The results of this study may assist with addressing the nursing shortage in rural and northern areas through improved retention strategies of RPNs.

Patterns of Health Services Utilization in Rural Canada

Canadians value ease of access to their health services. Although many studies have focused on accessibility to health services in Canada, few have examined rural-urban differences in this aspect, particularly from a national perspective. Yet disparities in access to health services exist between rural and urban populations, as do the challenges of delivering health care to more remote areas or to those with small populations.

“Canada’s Rural Communities: Understanding Rural Health and Its Determinants” is a three-year research project co-funded by the Canadian Population Health Initiative (CPHI) of the Canadian Institute for Health Information (CIHI) and the Public Health Agency of Canada (PHAC). It involves investigators from the Public Health Agency of Canada, the Centre for Rural and Northern Health Research (CRaNHR) at Laurentian University, and other researchers. The first publication of the research project was How Healthy Are Rural Canadians? An Assessment of Their Health Status and Health Determinants;Footnote 1a1a this, the second publication, is a descriptive analysis of the utilization patterns of a broad range of health services by rural residents compared to their urban counterparts.

Autophagy gets a brake: DAP1, a novel mTOR substrate, is activated to suppress the autophagic process

Autophagy, a highly regulated catabolic process, is controlled by the action of positive and negative regulators. While many of the positive mediators of autophagy have been identified, very little is known about negative regulators that might counterbalance the process. We recently identified deathassociated protein 1 (DAP1) as a suppressor of autophagy and as a novel direct substrate of mammalian target of rapamycin (mTOR). We found that DAP1 is functionally silent in cells growing under rich nutrient supplies through mTOR-dependent inhibitory phosphorylation on two sites, which were mapped to Ser3 and Ser51. During amino acid starvation, mTOR activity is turned off resulting in a rapid reduction in the phosphorylation of DAP1. This caused the conversion of the protein into a suppressor of autophagy, thus providing a buffering mechanism that counterbalances the autophagic flux and prevents its overactivation under conditions of nutrient deprivation. Based on these studies we propose the “gas and brake” concept in which mTOR, the main sensor that regulates autophagy in response to amino acid deprivation, also controls the activity of a specific balancing brake to prevent the overactivation of autophagy.

Patterns of health services utilization in rural Canada

CONTEXT OF THIS STUDY: Canadians value ease of access to their health services. Although many studies have focused on accessibility to health services in Canada, few have examined rural-urban differences in this aspect, particularly from a national perspective. Yet disparities in access to health services exist between rural and urban populations, as do the challenges of delivering health care to more remote areas or to those with small populations. "Canada's Rural Communities: Understanding Rural Health and Its Determinants" is a three-year research project co-funded by the Canadian Population Health Initiative (CPHI) of the Canadian Institute for Health Information (CIHI) and the Public Health Agency of Canada (PHAC). It involves investigators from the Public Health Agency of Canada, the Centre for Rural and Northern Health Research (CRaNHR) at Laurentian University, and other researchers. The first publication of the research project was How Healthy Are Rural Canadians? An Assessment of Their Health Status and Health Determinants; this, the second publication, is a descriptive analysis of the utilization patterns of a broad range of health services by rural residents compared to their urban counterparts.

Bioinspired peptide nanotubes: deposition technology, basic physics and nanotechnology applications

Synthetic peptide monomers can self-assemble into PNM such as nanotubes, nanospheres, hydrogels, etc. which represent a novel class of nanomaterials. Molecular recognition processes lead to the formation of supramolecular PNM ensembles containing crystalline building blocks. Such low-dimensional highly ordered regions create a new physical situation and provide unique physical properties based on electron-hole QC phenomena. In the case of asymmetrical crystalline structure, basic physical phenomena such as linear electro-optic, piezoelectric, and nonlinear optical effects, described by tensors of the odd rank, should be explored. Some of the PNM crystalline structures permit the existence of spontaneous electrical polarization and observation of ferroelectricity. The PNM crystalline arrangement creates highly porous nanotubes when various residues are packed into structural network with specific wettability and electrochemical properties. We report in this review on a wide research of PNM intrinsic physical properties, their electronic and optical properties related to QC effect, unique SHG, piezoelectricity and ferroelectric spontaneous polarization observed in PNT due to their asymmetric structure. We also describe PNM wettability phenomenon based on their nanoporous structure and its influence on electrochemical properties in PNM. The new bottom-up large scale technology of PNT physical vapor deposition and patterning combined with found physical effects at nanoscale, developed by us, opens the avenue for emerging nanotechnology applications of PNM in novel fields of nanophotonics, nanopiezotronics and energy storage devices.

DAP1, a novel substrate of mTOR, negatively regulates autophagy

Autophagy, a catabolic process responsible for the degradation of cytosolic components, is upregulated when nutrient supplies are limited. A critical step in autophagy induction comprises the inactivation of a key negative regulator of the process, the Ser/Thr kinase mammalian target of rapamycin (mTOR). Thus far, only a few substrates of mTOR that control autophagy have been identified, including ULK1 and Atg13, both of which function as positive mediators. Here we identify death-associated protein 1 (DAP1) as a novel substrate of mTOR that negatively regulates autophagy. The link of DAP1 to autophagy was first apparent in that its knockdown enhanced autophagic flux and in that it displayed a rapid decline in its phosphorylation in response to amino acid starvation. Mapping of the phosphorylation sites and analysis of phosphorylation mutants indicated that DAP1 is functionally silenced in growing cells through mTOR-dependent phosphorylations on Ser3 and Ser51. Inactivation of mTOR during starvation caused a rapid reduction in these phosphorylation sites and converted the protein into an active suppressor of autophagy. These results are consistent with a "Gas and Brake" model in which mTOR inhibition also controls a buffering mechanism that counterbalances the autophagic flux and prevents its overactivation under nutrient deprivation.

Type 1 diabetes in Jewish Ethiopian immigrants in Israel: HLA class II immunogenetics and contribution of new environment

The interrelationship between human leukocyte antigen immunogenetics and environmental factors and their contribution to the emergence of type 1 diabetes (T1D) were studied in Jewish immigrants from Ethiopia in Israel. This community displays high incidence of T1D, and is unique both by its ethnic segregation and its rapid exposure to a new environment after the immigration. The study population consisted of 152 Ethiopian Jews living in Israel, 33 with T1D and 119 unrelated controls. Human leukocyte antigen class II susceptible and protective alleles in the Jewish Ethiopian patients were similar to those in patients of other ethnic groups in Israel and in non-Jewish Ethiopian patients, with a few exceptions. Three haplotypes were markedly associated with diabetes in Jewish Ethiopian patients: DRB1*0301 DQA1*05 DQB1*02 (OR 4.4, p < 0.001); DRB1*0404 DQA1 03 DQB1*0302 (OR 19.2, p = 0.006), and DRB1*0405 DQA1*03 DQB1*0302 (OR 87.8, p < 0.001). The highly susceptible allele DRB1*0301 was more common in the general Ethiopian population (25.2%) than in all other ethnic groups in Israel, which may render this community prone to the disease. The age at onset of disease in patients with two susceptible haplotypes was negatively correlated with the duration of living in Israel (r = -0.621, p = 0.04). We concluded that ongoing exposure of genetically predisposed immigrants from Ethiopia to diabetogenic environmental factors eventually leads to a high incidence of overt diabetes in this ethnic group.

Greater prevalence of iron deficiency in overweight and obese children and adolescents

OBJECTIVE

To assess whether overweight children and adolescents, who often have poor dietary habits, are at increased risk of iron deficiency (ID).

METHODS

The study sample included 321 children and adolescents followed in two endocrine centers in Israel between 1999 and 2001. The subjects were divided into three groups on the basis of body mass index (BMI) for age and gender as follows: group 1-BMI below 85th percentile (normal weight); group 2-BMI above 85th, but below 97th percentile (overweight); and group 3-BMI above 97th percentile (obese). ID was defined as iron levels <8 micromol/l (45 mcg/dl), and iron-deficiency anemia (IDA) was defined as ID and hemoglobin level below 2 standard deviation score (SDS) for the mean for age and gender.

RESULTS

Iron levels below 8 micromol/l (45 mcg/dl) were noted in 38.8% of the obese children and 12.1% of the overweight children, compared with 4.4% of the normal-weight group (P<0.001). There was a significant negative correlation of low iron levels with BMI SDS (r=-0.44, P<0.001), but not with age or gender. Among the children with ID, 26.6% also had IDA. Groups 1, 2, and 3 accounted for 6.7%, 35%, and 58.3% of the children with IDA, respectively.

CONCLUSIONS

ID is common in overweight and obese children. A significantly greater proportion of obese than normal-weight children have IDA. Insufficient dietary intake of iron, whether absolute or relative to body mass, and increased iron needs may be a result of unbalanced nutrition or repeated short-term restrictive diets. Because of potentially harmful effects of ID, obese children should be routinely screened and treated as necessary.

Family-centered care in Ontario general hospitals: the views of pediatric nurses

Registered nurses and registered practical nurses working on pediatric units in 35 Ontario general hospitals participated in a study that examined their perceptions and practices of family-centered care (FCC). The Family-Centered Care Questionnaire-Revised (FCCQ-R) was used to collect the data. The participants were asked to rate their level of agreement regarding necessary elements (perceptions) of family-centered care and whether these elements are part of their current work (practice). The participants had a reasonable knowledge of the necessary elements of family-centered care, but were not consistently including these in their every day work. A number of barriers to the implementation of family-centered care were also identified. Perception and practice scores were higher among those who had participated in continuing education on family-centered care than those who had not. The findings suggest that some nurses may be having difficulties shifting from a medical helping model of care to an enabling helping model of care, which is considered the foundation of family-centered care. Difficulties in implementing family-centered care appear to be systemic, both at the unit and organizational level. Based on the findings, implications for practice, education and research are suggested.

Severe pulmonary disease in association with Crohn's disease in a 13-year-old girl

Pulmonary manifestations of Crohn's disease are infrequent in adults and even less common in children. Our literature search found only a few cases of Crohn's disease causing pulmonary manifestations in children. We report on the case of a 13-year-old girl in whom severe pulmonary disease was found four years after the onset of Crohn's disease. Open lung biopsy uncovered bronchiolitis obliterans and granulomatous lung disease. Aggressive treatment has yielded gradual improvement. This case emphasizes the importance of recognizing the association, the differential diagnosis, and treatment implications.

[Type 2 diabetes among adolescents in Israel]

Type 2 diabetes has been considered rare in children and adolescents. Recently, increase in the incidence of type 2 diabetes has been reported among adolescents in various parts of the world. We report the occurrence of type 2 diabetes among adolescents in Israel. A boy of 14 and girls of 16.5 and 17 were pubertal and extremely obese, with a body mass index (BMI) between 39-47 kg/m2. Acanthosis nigricans, elevated diastolic blood pressure, and hirsutism with menstrual disorders, were associated with insulin resistance, and should raise suspicion of type 2 diabetes. Significant obesity and strong family histories of type 2 diabetes appeared to be important risk factors. Since type 2 leads to long-term morbidity and mortality, its early identification and appropriate treatment are crucial.

Severe pulmonary disease in association with Crohn's disease in a 13-year-old girl

Pulmonary manifestations of Crohn's disease are infrequent in adults and even less common in children. Our literature search found only a few cases of Crohn's disease causing pulmonary manifestations in children. We report on the case of a 13-year-old girl in whom severe pulmonary disease was found four years after the onset of Crohn's disease. Open lung biopsy uncovered bronchiolitis obliterans and granulomatous lung disease. Aggressive treatment has yielded gradual improvement. This case emphasizes the importance of recognizing the association, the differential diagnosis, and treatment implications.

Endoscopic transnasal transsphenoidal microsurgery versus the sublabial approach for the treatment of pituitary tumors: endonasal complications

OBJECTIVE

To evaluate the nasal complications after transnasal transsphenoidal operations for pituitary tumors, comparing two surgical techniques: traditional sublabial transseptal and endoscopic transseptal techniques.

STUDY DESIGN

We retrospectively evaluated by self-reported questionnaire and endoscopic examination the nasal condition of 40 consecutive patients with pituitary tumors: 20 patients had endoscopic surgery and 20 had surgery with the traditional sublabial technique.

RESULTS

Compared with the traditional technique, the endoscopic approach was associated with a shorter operative time (about 40 min), shorter hospitalization time (about half), absence of recurrent epistaxis snoring and denture problems, and lower incidence of septal perforation, synechia, and crust formation. Furthermore, loss of nasal tip projection was found only in the group that had surgery with the sublabial technique.

CONCLUSIONS

Endoscopically guided transseptal transsphenoidal surgery is simple to perform and time-saving, and it results in fewer nasal and denture complications than the sublabial technique. At the same time, it allows the surgeon all the benefits of the binocular microscopic surgical field that are associated with the traditional approach.

[Preservation of the great posterior auricular nerve during superficial parotidectomy]

Sensory loss in the operative area after superficial parotidectomy is one of the complications which disturbs the patient. The greater auricular nerve, which stems from the cervical plexus, supplies sensation to the area. Sacrifice of the nerve during superficial parotidectomy causes sensory loss in the area. We investigated the degree of sensory loss in the operative area after superficial parotidectomy in 10 patients in whom the posterior branch of the greater auricular nerve was preserved and compared the results with those in whom it was not, a year after operation. There was more sensory loss when the greater auricular nerve was sacrificed. We therefore suggest preserving the posterior branch of the greater auricular nerve during superficial parotidectomy if at all possible.

Assessment and management of children's pain in community hospitals

Registered nurses (n = 72) working in 10 paediatric units in community hospitals in north-eastern Ontario, Canada, participated in a descriptive study investigating how nurses assess and manage pain in children. A four-part questionnaire was used to collect the self-reported data. Twenty-five (36%) of the respondents defined pain as an individual and personal experience and another 25 (36%) respondents defined pain as a more or less localized sensation or discomfort resulting from the stimulation of specialized nerve endings. In response to three different clinical situations, the subjects' mean pain ratings were: 5.72 for an infant; 7.34 for a 3-year-old; and 7.29 for a 12-year-old child. The criterion 'nurses' judgment' was cited as being used frequently in both the assessment and decision making process; however, there was indication that some of the current knowledge in the assessment and management of pain in children was not known or being used.

Giant adrenal cyst in the newborn: perinatal diagnosis and management

Routine ultrasound examination in a pregnant 20-year-old woman at 32 weeks demonstrated a cystic structure in the fetal abdomen. Follow-up till term showed no substantial change in size. After birth the cyst could easily be palpated as an epigastric mass. Ultrasonography followed by a barium meal suggested, among other things, the diagnosis of gastric duplication. At exploratory laparotomy the cyst proved to be of adrenal origin. The diagnosis and therapeutic options are discussed.

Coping with the Gulf war: subculture differences among ischemic heart disease patients in Israel

The purpose of this study was to assess short term effects of the Gulf war on ischemic heart disease patients of different ethnic origin. Three dimensions of patients' reactions to the war situation were studied: psychological, physical and behavioral. The study first focused on changes in patients' responses on these dimensions over three stages of the war, differentiated according to degree of threat. Second, differences stemming from ethnic origin were examined among patients who live in the same geographical region, use the same health services and were exposed to the same threatening life event. One hundred ischemic heart disease patients were interviewed while waiting in outpatient hospital clinics for a regular examination at the end of the war. The results of intrapersonal comparisons showed that the intensity of responses, as expected, increased significantly on the three dimensions from the week before the war started to the first week of the war, which was the most stressful period for Israelis. During the last week of the war, however, when stress was significantly reduced, the expected change was found primarily with regard to psychologic responses. That is, worries were significantly reduced, but no significant reduction in frequency of anginal pain and in drug consumption followed, indicating differences in the adjustment process on the psychologic and physical levels. Subcultural differences were found in the studied responses: Patients of Asian or North African countries of origin reported having more frequent anginal pains, and consuming more drugs than patients from Western countries.(ABSTRACT TRUNCATED AT 250 WORDS)

Construction of Minimal n-2-n Encoders for Any n

The encoding problem (Rumelhart and McClelland 1986) is an important canonical problem. It has been widely used as a benchmark. Here, we have analytically derived minimal-sized nets necessary and sufficient to solve encoding problems of arbitrary size. The proofs are constructive: we construct n-2-n encoders and show that two hidden units are also necessary for n > 2. Moreover, the geometric approach employed is general and has much wider applications. For example, this method has also helped us derive lower bounds on the redundancy necessary for achieving complete fault tolerance (Phatak and Koren 1992a,b).

Perceived mood and exercise behaviors of cardiac rehabilitation program referrals

The objective of this study was to examine how 65 clients referred to a cardiac rehabilitation program perceived their current mood, severity of illness, exercise behaviors, and hence, quality of life. The theoretical perspective for this study was derived from King's (1981) theory of goal attainment. The individual's perceptions are a fundamental element of goal attainment. A telephone survey was developed to gather data on demographics, exercise intensity and participation, severity of illness at time of hospital discharge and time of interview as well as responses to a mood adjective check list (Lubin, 1981). Analysis indicated that exercise was a valued behavior for the majority of subjects. All subjects perceived that the severity of their heart condition had changed from more to less severe. Furthermore, those who exercised felt healthy and merry, while those who did not exercise felt miserable.