[The alar vertical section or résection technique in rhinoplasty]. / Section et/ou résection verticale des alaires en rhinoplastie.

Nasal tip plasty is a real functional and aesthetical challenge in rhinoplasty. Many techniques have been described with different degrees of variability. The classic technique is the vertical division of the domes with section of the intermediate domes and directed healing without suture or cartilaginous grafting. The technique is based on an alar section or resection combined with a transdomal suture (STD) which allows control of the projection and rotation of the nasal tip.

Use of chemotherapy near the end of life: what factors matter?

Background: Use of chemotherapy near the end of life in patients with metastatic cancer is often ineffective and toxic. Data about the factors associated with its use remain scarce, especially in Europe. Methods: Nationwide, register-based study including all hospitalized patients aged ≥20 years who died from metastatic solid tumors in France between 2010 and 2013. Results: A total of 279 846 hospitalized patients who died from metastatic cancer were included. During the last month before death, 19.5% received chemotherapy (including 11.3% during the last 2 weeks). Female sex (OR= 0.96, 95% CI= 0.93-0.98), older age (OR= 0.70, 95% CI= 0.69-0.71 for each 10-year increase) and higher number of chronic comorbidities (OR= 0.83, 95% CI= 0.82-0.84) were independently associated with lower rates of chemotherapy. Although patients with chemosensitive tumors were statistically more likely to receive chemotherapy during the last month before death (OR= 1.21, 1.18-1.25), this association was mostly fueled by testis and ovary tumors and we found no obvious pattern between the expected chemosensitivity of different cancers and the rates of chemotherapy use close to death. Compared with university hospitals, patients who died in for-profit clinics/hospital (OR= 1.40, 95% CI= 1.34-1.45), or comprehensive cancer centers (OR= 1.43, 95% CI= 1.36-1.50) were more likely to receive chemotherapy. Finally, high-volume centers and hospitals without palliative care units reported greater-than-average rates of chemotherapy near the end of life. Conclusion: among hospitalized patients with cancer, young individuals, treated in comprehensive cancer centers or in high-volume centers without palliative care units were the most likely to receive chemotherapy near the end of life. We found no evident pattern between the expected chemosensitivity of different cancers and the probability for patients to receive chemotherapy close to death.

Urinary mRNA for the Diagnosis of Renal Allograft Rejection: The Issue of Normalization.

Urinary messenger RNA (mRNA) quantification is a promising method for noninvasive diagnosis of renal allograft rejection (AR), but the quantification of mRNAs in urine remains challenging due to degradation. RNA normalization may be warranted to overcome these issues, but the strategies of gene normalization have been poorly evaluated. Herein, we address this issue in a case-control study of 108 urine samples collected at time of allograft biopsy in kidney recipients with (n = 52) or without (n = 56) AR by comparing the diagnostic value of IP-10 and CD3ε mRNAs-two biomarkers of AR-after normalization by the total amount of RNA, normalization by one of the three widely used reference RNAs-18S, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Hypoxanthine-guanine phosphoribosyltransferase (HPRT)-or normalization using uroplakin 1A (UPK) mRNA as a possible urine-specific reference mRNA. Our results show that normalization based on the total quantity of RNA is not substantially improved by additional normalization and may even be worsened with some classical reference genes that are overexpressed during rejection. However, considering that normalization by a reference gene is necessary to ensure polymerase chain reaction (PCR) quality and reproducibility and to suppress the effect of RNA degradation, we suggest that GAPDH and UPK1A are preferable to 18S or HPRT RNA.

Early Low Urinary CXCL9 and CXCL10 Might Predict Immunological Quiescence in Clinically and Histologically Stable Kidney Recipients.

We monitored the urinary C-X-C motif chemokine (CXCL)9 and CXCL10 levels in 1722 urine samples from 300 consecutive kidney recipients collected during the first posttransplantation year and assessed their predictive value for subsequent acute rejection (AR). The trajectories of urinary CXCL10 showed an early increase at 1 month (p = 0.0005) and 3 months (p = 0.0009) in patients who subsequently developed AR. At 1 year, the AR-free allograft survival rates were 90% and 54% in patients with CXCL10:creatinine (CXCL10:Cr) levels <2.79 ng/mmoL and >2.79 ng/mmoL at 1 month, respectively (p < 0.0001), and 88% and 56% in patients with CXCL10:Cr levels <5.32 ng/mmoL and >5.32 ng/mmoL at 3 months (p < 0.0001), respectively. CXCL9:Cr levels also associate, albeit less robustly, with AR-free allograft survival. Early CXCL10:Cr levels predicted clinical and subclinical rejection and both T cell- and antibody-mediated rejection. In 222 stable patients, CXCL10:Cr at 3 months predicted AR independent of concomitant protocol biopsy results (p = 0.009). Although its positive predictive value was low, a high negative predictive value suggests that early CXCL10:Cr might predict immunological quiescence on a triple-drug calcineurin inhibitor-based immunosuppressive regimen in the first posttransplantation year, even in clinically and histologically stable patients. The clinical utility of this test will need to be addressed by dedicated prospective clinical trials.

End-of-life care for hospitalized patients with metastatic melanoma in France: a nationwide, register-based study.

BACKGROUND: Although the aggressiveness of end-of-life cancer care has come under great scrutiny over the past two decades, little is known about the intensity of care and treatments in the last months of life of patients with metastatic melanoma. OBJECTIVES: To measure the prevalence of aggressive cancer care use, and to assess the frequency of palliative care referral over the course of the last 3 months of life of hospitalized patients who died from metastatic melanoma. METHODS: A nationwide register-based study in France was carried out, including all hospitalized adults aged ≥ 20 years who died from metastatic melanoma in metropolitan France between 2010 and 2013. RESULTS: Of 3889 patients who died from metastatic melanoma, 51·9% received chemotherapy in the last 3 months before death, 25·9% in the last month, 12·9% in the last 2 weeks and 7·6% in the last week. On average, patients were hospitalized for 31·7 days over the course of their last 3 months of life. During the final month before death, 12·0% of patients received radiation therapy, 14·0% received blood transfusion, 12·1% were transferred into an intensive care unit and 19·7% remained hospitalized continuously. Palliative care needs were identified in 78·4% of patients, with variations according to the type of facility. In total 17% of all patients died in palliative care inpatient units. CONCLUSIONS: Treatment intensity near the end of life of patients with metastatic melanoma raises concerns for the quality of care. There is a need for clinical guidelines and adequate support to facilitate patient-physician communication and to improve access to palliative care services.

Green and brown bridges between weeds and crops reveal novel Diaporthe species in Australia.

Diaporthe (syn. Phomopsis) species are well-known saprobes, endophytes or pathogens on a range of plants. Several species have wide host ranges and multiple species may sometimes colonise the same host species. This study describes eight novel Diaporthe species isolated from live and/or dead tissue from the broad acre crops lupin, maize, mungbean, soybean and sunflower, and associated weed species in Queensland and New South Wales, as well as the environmental weed bitou bush (Chrysanthemoides monilifera subsp. rotundata) in eastern Australia. The new taxa are differentiated on the basis of morphology and DNA sequence analyses based on the nuclear ribosomal internal transcribed spacer region, and part of the translation elongation factor-1α and ß-tubulin genes. The possible agricultural significance of live weeds and crop residues ('green bridges') as well as dead weeds and crop residues ('brown bridges') in aiding survival of the newly described Diaporthe species is discussed.

Multiple health care visits related to a pediatric emergency visit for young children with common illnesses.

UNLABELLED: We aim to describe the number of health care visits before and after pediatric emergency department (PED) visits for common illnesses in a French tertiary pediatric hospital. This was a prospective cohort study with 501 children under 6 years of age who were evaluated and discharged from a tertiary care PED. Enrollment occurred on eight randomly selected study days between November 2010 and June 2011. The caregivers were then contacted via telephone 8 days later to obtain follow-up data, including information about return visits to health care facilities. Multiple visits were made by 206 (41 %) children, previous visits had occurred for 139 (28 %) children, and return visits had occurred for 94 (19 %) children. Previous and return visits were made at the PED as well as in general practitioners' offices and private pediatric offices. The median age of the subjects was 18 months. Fever was the most common complaint and was associated with more frequent multiple heath care visits. CONCLUSION: Multiple heath care visits for the same illness are frequent, especially for febrile children. Interestingly, this phenomenon concerns every type of health care facility, including the PED, general practitioners' offices, and private pediatric offices. Further studies should be performed to achieve a better understanding of this phenomenon and to test specific interventions, such as parental education and improvement of the information system.

French national diagnostic and care protocol for Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis with a particular tropism for the coronary arteries. KD mainly affects male children between 6 months and 5 years of age. The diagnosis is clinical, based on the international American Heart Association criteria. It should be systematically considered in children with a fever, either of 5 days or more, or of 3 days if all other criteria are present. It is important to note that most children present with marked irritability and may have digestive signs. Although the biological inflammatory response is not specific, it is of great value for the diagnosis. Because of the difficulty of recognising incomplete or atypical forms of KD, and the need for urgent treatment, the child should be referred to a paediatric hospital as soon as the diagnosis is suspected. In the event of signs of heart failure (pallor, tachycardia, polypnea, sweating, hepatomegaly, unstable blood pressure), medical transfer to an intensive care unit (ICU) is essential. The standard treatment is an infusion of IVIG combined with aspirin (before 10 days of fever, and for a minimum of 6 weeks), which reduces the risk of coronary aneurysms. In case of coronary involvement, antiplatelet therapy can be maintained for life. In case of a giant aneurysm, anticoagulant treatment is added to the antiplatelet agent. The prognosis of KD is generally good and most children recover without sequelae. The prognosis in children with initial coronary involvement depends on the progression of the cardiac anomalies, which are monitored during careful specialised cardiological follow-up.

Impact of implementing French antibiotic guidelines for acute respiratory-tract infections in a paediatric emergency department, 2005-2009.

Acute respiratory tract infections (ARTIs) are the main reason for antibiotic prescription in children. In 2005, the French Drug Agency published guidelines to minimise inappropriate use of antibiotics for ARTI. The purpose of this study was to assess the impact of implementing these guidelines in a paediatric emergency department. We retrospectively analysed data collected prospectively in a French paediatric emergency department from November 2005 (date of guideline implementation) to October 2009. For each child diagnosed with ARTI, we collected age, diagnosis, and prescribed antibiotics. We computed antibiotic prescription rates in the study population. During the study period, 53,055 children were diagnosed with ARTI and 59% of the 22,198 antibiotic prescriptions given at discharge were related to ARTI. The proportion of ARTI patients given antibiotic prescriptions fell from 32.1% during the first year to 21% in year 4 (p<10(-4), Cochran-Armitage test). Amoxicillin-clavulanic acid and amoxicillin accounted for 50% and 34% of antibiotic prescriptions for ARTI, respectively. French antibiotic guidelines led to significant decreases in antibiotic prescription for ARTI in our paediatric emergency department.

Randomized trial of the effect of video training on residents' surgical skills in facial skin reconstructive surgery: A SQUIRE study.

OBJECTIVES: The purpose of this study was to evaluate the impact of facial skin reconstruction training videos for head and neck and maxillofacial surgery residents. MATERIAL AND METHODS: This randomized trial, conducted in France, involved residents in head and neck and maxillofacial surgery. A website was created containing facial skin reconstruction training videos. Selected residents performed facial skin flap dissections in the Paris School of Surgery. They were randomized into two groups, one receiving a standard course before the dissection, and the other a standard course plus a video of the flap ("no-video" and "video" groups). Each resident performed 4 facial flaps and was graded (blindly) during dissection. The main study endpoint was intergroup difference in grading score (out of 15). The article was written up following the SQUIRE-EDU (Standards for QUality Improvement Reporting Excellence in EDUcation) criteria. RESULTS: Eighteen residents were included. For the main endpoint, scores were significantly higher in the "video" than the "no-video" group (6 [IQR, 4: 9] vs. 10 [9: 12]; P<0.001). In addition, as secondary endpoint, "no-video" group residents requested more assistance (3 [2: 4] vs. 1 [1: 2] P<0.001). Power was lacking for any subgroup analysis according to year of residency or to the 4 flaps. CONCLUSION: Videos improved surgical residents' performance during dissections. However, these results would be difficult to transpose to real clinical conditions. They need validating in a larger study evaluating performance in real-life procedures.

Sensitivity and specificity of a rapid influenza diagnostic test in children and clinical utility during influenza A (H1N1) 2009 outbreak.

INTRODUCTION: The influenza A (H1N1) 2009 outbreak caused death and a disruption of public health services. Rapid influenza diagnostic tests (RIDT) could be helpful to ease the triage of patients and prevent an overload of emergency and laboratory facilities. OBJECTIVES: To compare the sensitivity and specificity of the Clearview Exact Influenza A&B test and real-time reverse transcription(RT)-PCR to detect influenza A (H1N1) 2009 in a paediatric emergency department of a paediatric teaching hospital in Paris, France. METHODS: 76 children with an influenza-like illness and either severe symptoms or an underlying medical condition were prospectively recruited between July 2009 and October 2009. RIDT and RT-PCR were simultaneously performed and compared. RESULTS: Among 39 influenza A (H1N1) 2009 RT-PCR-positive children (median age 5 years), 23 Clearview Exact Influenza A&B tests were positive. Sensitivity was 59% (95% CI 42.2 to 74) and specificity was 94.6% (95% CI 80.5 to 99.1). CONCLUSIONS: This study shows a sensitivity of RIDT of 59%, in agreement with other prospective studies, which could be useful in clinical practice for diagnosis influenza A (H1N1) 2009 in children. In outbreaks of a high prevalence, such as the 2009 outbreak, this test can help to prevent an overload of public health services.

Hepatic hydrothorax in a child and its management.

Hepatic hydrothorax is a rare complication of portal hypertension. The optimal treatment for this condition is liver transplantation. Liver transplantation is significantly more manageable in children who weigh more than 8 kg. Here, an implantable pleural access device was used in a 5-month-old infant for painless iterative punctures to relieve respiratory symptoms, while waiting for liver transplantation and the patient's growth. The patient underwent successful transplantation 3 months later with a more optimal weight.

Gestational diabetes mellitus screening and diagnosis: a prospective randomised controlled trial comparing costs of one-step and two-step methods.

OBJECTIVE: To conduct a cost minimisation analysis of three methods of gestational diabetes mellitus (GDM) screening and diagnosis. DESIGN: Prospective randomised controlled trial. SETTING: University teaching hospital. POPULATION: Pregnant women (n = 1594) presenting for GDM screening. METHODS: Women presenting for GDM screening, who consented to participate, were randomised to GR1 [1-hour, 50-g glucose screen (GS) +/- 3-hour, 100-g oral glucose tolerance test (OGTT)], GR2 (50-g GS +/- 2-hour, 75-g OGTT) or GR3 (2-hour, 75-g OGTT). Demographics, health and time/travel cost information were assessed for each glucose testing visit. MAIN OUTCOME MEASURES: Costs (direct and indirect) and prevalence of GDM diagnosis. RESULTS: The direct sampling costs of the glucose tests per woman were as follows: GS, CAN$12.57; 75-g OGTT, $36.10; 100-g OGTT, CAN$48.13. Among women in the two-step method groups diagnosed with GDM, 39% of the GR1 and 61% of the GR2 groups were diagnosed at the first step by GS > or = 10.3 mmol/l, according to the Canadian Diabetes Association recommendations, contributing to a lower total cost in these groups. The total costs per woman screened were as follows: GR1, CAN$91.61; GR2, CAN$89.03; GR3, CAN$108.38. The GDM prevalence was similar (3.7%, 3.7% and 3.6%, respectively). The higher costs of GR3 were related to more blood draws and the time required for all women to undergo the 2-hour OGTT. CONCLUSIONS: Careful consideration should be given to an internationally recommended method of universal screening for GDM which minimises the burden and cost for individual women and the healthcare system, yet provides diagnostic efficacy. The two-step method (GS +/- OGTT) accomplished this better than the one-step method (75-g OGTT).

Obstructive sleep apnoea and its association with gestational hypertension.

Hypertension develops in 10% of pregnancies. Snoring, a marker of obstructive sleep apnoea, is a newly identified risk factor for gestational hypertension. Moreover, obstructive sleep apnoea is an independent risk factor for incident hypertension in the non-pregnant population. The aim of the present study was to test the hypothesis that obstructive sleep apnoea is associated with new onset of hypertension among pregnant females. A case-control study was performed involving 17 pregnant females with gestational hypertension and 33 pregnant females without hypertension. Subjects were frequency-matched for gestational age and recruited in a tertiary obstetrical centre. Obstructive sleep apnoea was ascertained by polysomnography and defined by an apnoea/hypopnoea index (AHI) of >or=15 events x h(-1), without requirement for desaturation. The mean+/-sd AHI for normotensive pregnant females was 18.2+/-12.2 events x h(-1) compared with 38.6+/-36.7 events x h(-1) for females with hypertensive pregnancies. The crude odds ratio for the presence of obstructive sleep apnoea given the presence of gestational hypertension was 5.6. The odds ratio was 7.5 (95% confidence interval 3.5-16.2), based on a logistic regression model with adjustment for maternal age, gestational age, pre-pregnancy body mass index, prior pregnancies, and previous live births. In conclusion, gestational hypertension appears to be strongly associated with the presence of obstructive sleep apnoea.

Estradiol shortens the period of hamster circadian rhythms.

Continuous administration of estradiol benzoate by means of subcutaneously implanted capsules shortened the free-running circadian period of locomotor activity of blind hamsters (Mesocricetus auratus) that had had their ovaries removed. Estradiol also advanced the phase of the wheel running of sighted female hamsters without ovaries that were entrained to a photoperiod with 12 hours of light and 12 of darkness. These results, and findings from hamsters undergoing natural estrous cycles, indicate that endogenous estradiol is involved in the regulation of circadian periodicity.

Feasibility and reliability of Doppler flow recordings in the fetal aortic isthmus: a multicenter evaluation.

OBJECTIVES: To evaluate the performance of three different centers with respect to their ability to identify the fetal aortic isthmus (AoI) adequately and place a Doppler sample volume in the AoI correctly, and to address the reproducibility of the isthmic flow index (IFI) calculated from Doppler waveforms recorded in the three centers. METHODS: The three collaborating centers sent several ultrasonographic recordings taken at random over a 6-week period to the Saint-Justine Fetal Cardiology Unit (StJ-FCU). A performance quotient ((number of total readings - number of unsatisfactory results)/number of total readings) was calculated for each center by each of three judges, who were experienced fetal cardiologists, to assess the ability of each center to identify the isthmus and to place the Doppler sample volume (DSV) adequately. Intraclass correlation coefficients (ICC) were computed to quantify the variability of IFI measurements ((systolic + diastolic)/systolic flow velocity integrals). RESULTS: Fifty-five recordings were available for this study. Concerning isthmus identification, there was 100% agreement between the three judges from StJ-FCU and the performance quotients of Centers A, B and C were: 0.90, 0.95 and 1.00, respectively. For DSV positioning, agreement between the judges varied; for Judge 1 vs. Judge 2, kappa = 0.836 (95% CI, 0.651-1.000); for Judge 1 vs. Judge 3, kappa = 0.773 (95% CI, 0.557-1.000); for Judge 2 vs. Judge 3, kappa = 0.941 (95% CI, 0.805-1.000). The performance quotients of the three centers for DSV positioning were consistently lower than were those for identification of the isthmus, being 0.85, 0.76 and 0.92, respectively. The ICC between the first and second measurements of the IFI by Rater 1 was 0.96 (95% CI, 0.93-0.98, P < 0.001) and that between Raters 1 and 2 was 0.97 (95% CI, 0.95-0.99, P < 0.001). CONCLUSION: Adequate imaging of the fetal AoI can be achieved easily by a trained sonographer, while DSV positioning is challenging. The intra- and interrater variability of the IFI are low.

A combination of HLA-DQ beta Asp57-negative and HLA DQ alpha Arg52 confers susceptibility to insulin-dependent diabetes mellitus.

Family and population studies indicate that predisposition to insulin-dependent (type I) diabetes mellitus (IDDM) is polygenic. It has been shown that the absence of the aspartic acid in position 57 (Asp57) of the DQ beta chain is positively correlated to IDDM. However, Asp57-negative haplotypes do not always confer susceptibility and conversely, some Asp57-positive haplotypes seem to be disease associated. It has been suggested that other HLA class II sequences, probably belonging to the HLA DQA1 gene, confer susceptibility to IDDM. This report, based on extensive oligonucleotide dot blot hybridization of PCR-amplified DQA1 and DQB1 genes, reinforces the importance of the Asp57-negative DQ beta chain, but also introduces the possibility that a DQ alpha chain bearing an arginine in position 52 (Arg52) confers susceptibility to IDDM. A molecular model of susceptibility to IDDM is proposed. This model strongly suggests that the disease susceptibility correlates quantitatively with the expression at the cell surface of a heterodimer, composed of a DQ alpha-chain bearing an Arg52 and a DQ beta chain lacking an Asp57. In view of the respective positions of the two residues and their charge, we might anticipate that both residues DQ beta Asp57 and DQ alpha Arg52 are critical for modulation of susceptibility, presumably via viral-antigenic peptide and/or autoantigen presentation.

The circadian visual system, 2005.

The primary mammalian circadian clock resides in the suprachiasmatic nucleus (SCN), a recipient of dense retinohypothalamic innervation. In its most basic form, the circadian rhythm system is part of the greater visual system. A secondary component of the circadian visual system is the retinorecipient intergeniculate leaflet (IGL) which has connections to many parts of the brain, including efferents converging on targets of the SCN. The IGL also provides a major input to the SCN, with a third major SCN afferent projection arriving from the median raphe nucleus. The last decade has seen a blossoming of research into the anatomy and function of the visual, geniculohypothalamic and midbrain serotonergic systems modulating circadian rhythmicity in a variety of species. There has also been a substantial and simultaneous elaboration of knowledge about the intrinsic structure of the SCN. Many of the developments have been driven by molecular biological investigation of the circadian clock and the molecular tools are enabling novel understanding of regional function within the SCN. The present discussion is an extension of the material covered by the 1994 review, "The Circadian Visual System."

Intergeniculate leaflet: contributions to photic and non-photic responsiveness of the hamster circadian system.

The circadian visual system is able to integrate light energy over time, enabling phase response and Fos induction in the suprachiasmatic nucleus to increase in proportion to the total energy of the photic stimulus. In the present studies, the contribution of the intergeniculate leaflet to light energy integration by the hamster circadian rhythm system was evaluated. Fos protein is induced in intergeniculate leaflet neurons at much lower irradiance levels than seen in suprachiasmatic nucleus neurons. Bilateral N-methyl-d-aspartate lesions of the intergeniculate leaflet decreased phase response of the circadian locomotor rhythm to high irradiance and, in animals exposed to long duration light stimuli, reduced Fos induction in the suprachiasmatic nucleus. Normal photon integration, as indicated by attenuated rhythm phase shifts and Fos induction in suprachiasmatic nucleus cells in response to the energy in light stimuli, does not occur in the absence of the intergeniculate leaflet and is likely to be a property of the circadian rhythm system, rather than solely of the suprachiasmatic nucleus. Anatomical analysis showed that virtually no intergeniculate leaflet neurons projecting to the suprachiasmatic nucleus contain Fos induced by either light or locomotion in a novel wheel. However, cells projecting to the pretectum were found to contain novel-wheel induced Fos. The intergeniculate leaflet is implicated in the normal assessment of light by the circadian rhythm system, but the circuitry by which either photic or non-photic information gains access to the suprachiasmatic nucleus may be more complex than previously thought.

Complex organization of mouse and rat suprachiasmatic nucleus.

The suprachiasmatic nucleus, site of the dominant mammalian circadian clock, contains a variety of different neurons that tend to form groups within the nucleus. The present investigation used single and multiple label tract tracing and immunofluorescence methods to evaluate the relative locations of the neuron groups and to compare them with the distributions of the three major afferent projections, the retinohypothalamic tract, geniculohypothalamic tract and the serotonergic pathway from the median raphe nucleus. The suprachiasmatic nucleus has a complex order characterized by peptidergic cell groups (vasopressin, gastrin releasing peptide, vasoactive intestinal polypeptide, calbindin, calretinin, corticotrophin releasing factor and enkephalin) that, in most cases, substantially overlap. The retinohypothalamic tract projects bilaterally to virtually all the suprachiasmatic nucleus in both rat (predominantly contralateral) and mouse (symmetric) and its terminal field overlaps that for the geniculohypothalamic tract, but with distinctions visible according to density criteria; neither provides more than sparse innervation of the dorsomedial suprachiasmatic nucleus. In the mouse, the serotonergic terminal field is densest medially and ventrally, but is also distributed elsewhere with varying density. The serotonergic terminal plexus in the rat is densest centromedially and largely, but not completely, overlaps the complete distribution of retinal terminals with density much reduced in the lateral suprachiasmatic nucleus. The locations of vasopressin neurons, retinohypothalamic tract terminals and serotonergic (mouse, rat) or geniculohypothalamic tract (rat) provide evidence for three clear, but not exclusionary, sectors of the suprachiasmatic nucleus. The data, in conjunction with emerging knowledge concerning rhythmically dynamic changes in the size of regions of neuropeptide gene expression in suprachiasmatic nucleus cells, support the view that suprachiasmatic nucleus organization is more complex than a simple "core" and "shell" arrangement. While generalizations about suprachiasmatic nucleus organization can be made with respect to location of cell phenotypes or terminal fields, oversimplification may hinder, rather than facilitate, understanding of suprachiasmatic nucleus structure-function relationships.