Incorporating Bereaved Parents as Faculty Facilitators and Educators in Teaching Principles of Palliative and End-of-Life Care

BACKGROUND:

Education and training for interdisciplinary pediatric providers requires training in principles of palliative and end-of-life (EOL) care. The experiences of bereaved parents can inform and enhance palliative care educational curricula in uniquely powerful and valuable ways. The objective of this study is to present an innovative palliative care educational program facilitated by trained bereaved parents who serve as volunteer educators in local and national palliative care educational forums and to describe how incorporation of bereaved parents in these educational forums affects participant comfort with communication and management of children at the EOL.

METHODS:

Parent educators underwent both general and session-specific training and participated in debriefings following each session. Survey tools were developed or adapted to determine how bereaved parent educators affected participant experiences in 3 different educational forums. Pre- and postsession surveys with incorporation of retrospective preprogram assessment items to control for response shift were used in the evaluation of institutional seminars on pediatric palliative and EOL care and role-play-based communication training sessions. Results from feedback surveys sent to attendees were used to appraise the participants' experience at the international oncology symposium.

RESULTS:

Involvement of trained parent educators across diverse, interdisciplinary educational forums improved attendee comfort in communicating with, and caring for, patients and families with serious illness. Importantly, parent educators also derive benefit from involvement in educational sessions with interdisciplinary clinicians.

CONCLUSIONS:

Integration of bereaved parents into palliative and EOL care education is an innovative and effective model that benefits both interdisciplinary clinicians and bereaved parents.

Going straight to the source: A pilot study of bereaved parent-facilitated communication training for pediatric subspecialty fellows

BACKGROUND

Medical trainees consistently report suboptimal instruction and poor self-confidence in communication skills. Despite this deficit, few established training programs provide comprehensive, pediatric-specific communication education, particularly in the provision of "bad news." To our knowledge, no programs currently use bereaved parent educators to facilitate communication training for pediatric subspecialty trainees.

PROCEDURE

The authors designed and implemented a pilot communication training seminar in which bereaved parent educators and faculty facilitators led small groups in interactive, role-play scenarios. Surveys incorporating a retrospective preprogram assessment item to account for response-shift bias were used to assess short- and long-term changes in trainee comfort with delivering "bad news."

RESULTS

Fifteen pediatric fellowship trainees participated in the communication seminar; complete data were available for 12 participants. After accounting for response-shift bias, participants reported significant improvement in overall preparedness, breaking bad news to a patient and family, and including the adolescent or young adult patient in conversations. Additionally, participants reported a significant improvement in their ability to address a patient and family's need for information, emotional suffering at the end of life (EOL), if and when a patient should be included in the conversation, and EOL care decisions. The participant's self-perceived improvement in comfort and preparedness persisted over time.

CONCLUSIONS

Communication training for pediatric subspecialty trainees using bereaved parent educators is feasible and effective. Both medical trainee and bereaved parent participants benefited from involvement in this pilot study. Further iterations of this training will be modified to assess objective measures of improvement in trainees' communication skills.

Research Priorities in Pediatric Palliative Care

OBJECTIVE

To synthesize the perspectives of a broad range of pediatric palliative care (PPC) clinicians and parents, to formulate a consensus on prioritization of the PPC research agenda.

STUDY DESIGN

A 4-round modified Delphi online survey was administered to PPC experts and to parents of children who had received PPC. In round 1, research priorities were generated spontaneously. Rounds 2 and 3 then served as convergence rounds to synthesize priorities. In round 4, participants were asked to rank the research priorities that had reached at least 80% consensus.

RESULTS

A total of 3093 concepts were spontaneously generated by 170 experts and 72 parents in round 1 (65.8% response rate [RR]). These concepts were thematically organized into 78 priorities and recirculated for round 2 ratings (n = 130; 53.7% RR). Round 3 achieved response stability, with 31 consensus priorities oscillating within 10% of the mode (n = 98; 75.4% RR). Round 4 resulted in consensus recognition of 20 research priorities, which were thematically grouped as decision making, care coordination, symptom management, quality improvement, and education.

CONCLUSIONS

This modified Delphi survey used professional and parental consensus to identify preeminent PPC research priorities. Attentiveness to these priorities may help direct resources and efforts toward building a formative evidence base. Investigating PPC implementation approaches and outcomes can help improve the quality of care services for children and families.

Best practices for pediatric palliative cancer care: a primer for clinical providers

Cancer is the leading cause of disease-related death in children and adolescents. Pediatric patients with cancer suffer greatly at the end of life. However, palliative care interventions can reduce suffering and significantly improve the care of these patients and their families. A large percentage of pediatric deaths occur outside of the hospital setting where pediatric palliative resources may not be readily available. Patients in the home setting may be cared for by community hospice programs, which are typically staffed for adult populations. Increasingly, nonpediatric providers are asked to provide palliative care for children and adolescents at the end of life, yet they receive little formal training in this area. This review focuses on the principles of best practice in the provision of palliative care for children and adolescents with cancer. Our intent is to aid clinical providers in delivering optimal care to this patient population. Topics unique to pediatric palliative care that are addressed include: providing pain and symptom management in the broad pediatric range from neonate to adolescent; caring for and interacting with developmentally distinct groups; engaging in shared decision making with parents and adolescents; providing accommodations for prognoses that are often more uncertain than in adult patients; and delivering concurrent disease-directed therapy with palliative care.

The ontology of craniofacial development and malformation for translational craniofacial research

We introduce the Ontology of Craniofacial Development and Malformation (OCDM) as a mechanism for representing knowledge about craniofacial development and malformation, and for using that knowledge to facilitate integrating craniofacial data obtained via multiple techniques from multiple labs and at multiple levels of granularity. The OCDM is a project of the NIDCR-sponsored FaceBase Consortium, whose goal is to promote and enable research into the genetic and epigenetic causes of specific craniofacial abnormalities through the provision of publicly accessible, integrated craniofacial data. However, the OCDM should be usable for integrating any web-accessible craniofacial data, not just those data available through FaceBase. The OCDM is based on the Foundational Model of Anatomy (FMA), our comprehensive ontology of canonical human adult anatomy, and includes modules to represent adult and developmental craniofacial anatomy in both human and mouse, mappings between homologous structures in human and mouse, and associated malformations. We describe these modules, as well as prototype uses of the OCDM for integrating craniofacial data. By using the terms from the OCDM to annotate data, and by combining queries over the ontology with those over annotated data, it becomes possible to create "intelligent" queries that can, for example, find gene expression data obtained from mouse structures that are precursors to homologous human structures involved in malformations such as cleft lip. We suggest that the OCDM can be useful not only for integrating craniofacial data, but also for expressing new knowledge gained from analyzing the integrated data.

Red cell alloimmunization in a diverse population of transfused patients with thalassaemia

Red blood cell (RBC) transfusion is the primary treatment for severe forms of thalassaemia. Pre-storage screening has resulted in decreased transfusion-transmitted infections, but anti-RBC antibodies remain a major problem. We report on 697 participants who had ever received transfusions. Allo- and autoantibody rates were compared with respect to splenectomy status, ethnicity, diagnosis, duration of transfusions, treatment centre, and age at transfusion initiation, together with rates before and after 1990, when leucoreduction methods were routine at thalassaemia treatment centres. Allo- and autoantibodies were reported in 115 (16·5%) and 34 (4·9%) subjects, respectively. Splenectomized patients were more likely to have alloantibodies [odds ratio (OR) = 2·528, P ≤ 0·0001], or autoantibodies (OR = 2·590, P = 0·0133). Alloantibodies occurred in 19 of 91 (21%) splenectomized subjects who started transfusion after 1990, and only 18 of 233 (7·7%) nonsplenectomized subjects (P < 0·001). Data from this study demonstrate that RBC antibodies continue to develop in chronically transfused thalassaemia patients at a high rate. Splenectomy preceded the development of antibodies in most cases. Increased rates of RBC sensitization among splenectomized patients is concerning and deserves further study.

Education and employment status of children and adults with thalassemia in North America

BACKGROUND

Advances in the management of thalassemia have resulted in increased life expectancy and new challenges. We conducted the first survey of education and employment status of people with thalassemia in North America.

PROCEDURES

A total of 633 patients (349 adults and 284 school age children) enrolled in the Thalassemia Clinical Research Network (TCRN) registry in Canada and the U.S. were included in the data analysis. Predictors considered for analysis were age, gender, race/ethnicity, site of treatment (Canada vs. United States), transfusion and chelation status, serum ferritin, and clinical complications.

RESULTS

Seventy percent of adults were employed of which 67% reported working full-time. Sixty percent had a college degree and 14% had achieved some post-college education. Eighty-two percent of school age children were at expected grade level. In a multivariate analysis for adults, Whites (OR = 2.76, 95% CI: 1.50-5.06) were more likely to be employed compared to Asians. Higher education in adults was associated with older age (OR = 1.67, 95% CI: 1.29-2.15), female gender (OR = 2.08, 95% CI: 1.32-3.23) and absence of lung disease (OR = 14.3, 95% CI: 2.04-100). Younger children (OR = 5.7 for 10-year increments, 95% CI: 2.0-16.7) and Canadian patients (OR = 5.6, 95% CI: 1.5-20) were more likely to be at the expected education level. Neither transfusion nor chelation was associated with lower employment or educational achievement.

CONCLUSIONS

Individuals with thalassemia in North America can achieve higher education; however, full-time employment remains a problem. Transfusion and chelation do not affect employment or education status of this patient population.

Transition matrix population model for dust mite Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

A transition matrix model of the population dynamics of the European house dust mite, Dermatophagoides pteronyssinus (Trouessart) (Acari: Pyroglyphidae), is described. It can model continuously varying conditions by forming transition matrices by interpolation between known transition matrices constructed from experimental data. Finite carrying capacity is modeled by modifying the population distribution vector at each time-step by using a form of the Skellam model, which is derived from the assumption that in competition each successful animal gets all it requires, and the unsuccessful animals get insufficient resources for survival or reproduction. The transition matrix model does not require all mites to have the same survivorship, life-stage durations, fecundity, and so on. Life table data to drive the model is taken from two sources, one source of which requires using the mean and standard deviation of the duration of each stage to synthesize a range of duration times and a range of transition probabilities to the next stage, thus ensuring variability between mites. Where synthesized data are used, significant long-lasting oscillations in dust mite levels are modeled, which does not happen when modeling with unsynthesized data, and is unlikely to occur in the field. Under conditions normally met with in the microenvironment (bedding, base of carpet, soft furnishing) of D. pteronyssinus, finite carrying capacity is essential to prevent unbounded population growth. The model is compared with other workers' field data with fair agreement. It is argued that shortcomings in the available data rather than the model are the principal reasons for differences between field and modeled results.

Update on thalassemia: clinical care and complications

beta-Thalassemia, originally named Cooley anemia, is an inherited blood disease. Various types of thalassemia are inherited anemias caused by mutations at the globin gene loci on chromosomes 16 and 11, affecting the production of alpha- or beta-globin protein, respectively. The combination of early diagnosis, improvements in monitoring for organ complications, and advances in supportive care have enabled many patients who have severe thalassemia syndromes to live productive, active lives well into adulthood.

Relative response of patients with myelodysplastic syndromes and other transfusion-dependent anaemias to deferasirox (ICL670): a 1-yr prospective study

OBJECTIVES/METHODS

This 1-yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3-81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond-Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or beta-thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC).

RESULTS

In patients with baseline LIC > or = 7 mg Fe/g dry weight, deferasirox initiated at 20 or 30 mg/kg/d produced statistically significant decreases in LIC (P < 0.001); these decreases were greatest in MDS and least in DBA. As chelation efficiency and iron excretion did not differ significantly between disease groups, the differences in LIC changes are consistent with mean transfusional iron intake (least in MDS: 0.28 +/- 0.14 mg/kg/d; greatest in DBA: 0.4 +/- 0.11 mg/kg/d). Overall, LIC changes were dependent on dose (P < 0.001) and transfusional iron intake (P < 0.01), but not statistically different between disease groups. Changes in serum ferritin and LIC were correlated irrespective of disease group (r = 0.59), supporting the potential use of serum ferritin for monitoring deferasirox therapy. Deferasirox had a safety profile compatible with long-term use. There were no disease-specific safety/tolerability effects: the most common adverse events were gastrointestinal disturbances, skin rash and non-progressive serum creatinine increases.

CONCLUSIONS

Deferasirox is effective for reducing iron burden with a defined, clinically manageable safety profile in patients with various transfusion-dependent anaemias. There were no disease-specific adverse events. Once differences in transfusional iron intake are accounted for, dose-dependent changes in LIC or serum ferritin are similar in MDS and other disease groups.

Urinary hepcidin in congenital chronic anemias

BACKGROUND

Hepcidin, a regulator for iron homeostasis, is induced by inflammation and iron burden and suppressed by anemia and hypoxia. This study was conducted to determine the hepcidin levels in patients with congenital chronic anemias.

PROCEDURE

Forty-nine subjects with anemia, varying degrees of erythropoiesis and iron burden were recruited. Eight children with immune thrombocytopenia were included as approximate age-matched controls. Routine hematologic labs and urinary hepcidin (uhepcidin) levels were assessed. For thalassemia major (TM) patients, uhepcidin was obtained pre- and post-transfusion.

RESULTS

In TM, uhepcidin levels increased significantly after transfusion, demonstrated wide variance, and the median did not significantly differ from controls or thalassemia intermedia (TI). In both thalassemia syndromes, the hepcidin to ferritin ratio, a marker of the appropriateness of hepcidin expression relative to the degree of iron burden, was low compared to controls. In TI and sickle cell anemia (SCA), median uhepcidin was low compared to controls, P = 0.013 and <0.001, respectively. In thalassemia subjects, uhepcidin levels were positively associated with ferritin. In subjects with SCA, uhepcidin demonstrated a negative correlation with reticulocyte count.

CONCLUSIONS

This study examines hepcidin levels in congenital anemias. In SCA, hepcidin was suppressed and inversely associated with erythropoietic drive. In thalassemic syndromes, hepcidin was suppressed relative to the degree of iron burden. Transfusion led to increased uhepcidin. In thalassemia, the relative influence of known hepcidin modifiers was more difficult to assess. In thalassemic syndromes where iron overload and anemia have opposing effects, the increased erythropoietic drive may positively influence hepcidin production.

Development of Dermatophagoides pteronyssinus (Acari: Pyroglyphidae) at constant and simultaneously fluctuating temperature and humidity conditions

House dust mites are found in almost all dwellings in New Zealand and are a major risk factor in the development of asthma and perennial allergic rhinitis. We studied the longevity, life stage length, and fecundity of a New Zealand strain of European house dust mite, Dermatophagoides pteronyssinus (Trouessart), at constant (23 degrees C, 75% RH) and the fluctuating conditions typically found in dry (18-25 degrees C, 60-38% RH) and damp (18-23 degrees C, 70-55% RH) New Zealand dust mite microhabitats in carpets. All the adult mites placed in the "dry" conditions died within 18 d. Mites in the "da conditions had developmental times, oviposition, and death rates that were not significantly different from constant conditions. These mites are tolerant of fluctuating temperatures, but they are more susceptible to environments that strongly fluctuate in humidity.

New developments in iron chelators

PURPOSE OF REVIEW

For three decades, deferoxamine has been the only approved iron chelator. This drug has an extremely short-half life and is not orally absorbed; thus, a search has been ongoing for alternative chelators with less onerous delivery. Recently, several oral iron chelators and variations of deferoxamine to prolong the half-life have been developed. These and the methods of monitoring iron overload are the subjects of this review.

RECENT FINDINGS

New chelators, combinations of chelators and regimens for known chelators and their safety and efficacy are being studied in important preclinical and clinical trials.

SUMMARY

The care and clinical outcomes of patients with thalassemia and other iron-overload disorders may be markedly improved by recent discoveries and novel approaches to chelation therapy.

A role for kisspeptins in the regulation of gonadotropin secretion in the mouse

Kisspeptins are products of the KiSS-1 gene, which bind to a G protein-coupled receptor known as GPR54. Mutations or targeted disruptions in the GPR54 gene cause hypogonadotropic hypogonadism in humans and mice, suggesting that kisspeptin signaling may be important for the regulation of gonadotropin secretion. To examine the effects of kisspeptin-54 (metastin) and kisspeptin-10 (the biologically active C-terminal decapeptide) on gonadotropin secretion in the mouse, we administered the kisspeptins directly into the lateral cerebral ventricle of the brain and demonstrated that both peptides stimulate LH secretion. Further characterization of kisspeptin-54 demonstrated that it stimulated both LH and FSH secretion, at doses as low as 1 fmol; moreover, this effect was shown to be blocked by pretreatment with acyline, a potent GnRH antagonist. To learn more about the functional anatomy of kisspeptins, we mapped the distribution of KiSS-1 mRNA in the hypothalamus. We observed that KiSS-1 mRNA is expressed in areas of the hypothalamus implicated in the neuroendocrine regulation of gonadotropin secretion, including the anteroventral periventricular nucleus, the periventricular nucleus, and the arcuate nucleus. We conclude that kisspeptin-GPR54 signaling may be part of the hypothalamic circuitry that governs the hypothalamic secretion of GnRH.

Galanin-like peptide as a link between metabolism and reproduction

Galanin-like peptide (GALP) is a hypothalamic neuropeptide that binds and activates galanin receptors in vitro. Following the discovery of GALP, researchers have attempted to properly place it in the context of galanin receptor physiology. Central injections of GALP have revealed some common actions with galanin, such as acutely increased food intake and suppression of the thyroid axis. Other actions are unique to GALP, such as long-term inhibition of food intake and stimulation of luteinizing hormone (LH) secretion in male rats. GALP and galanin also produce differential effects on expression of the immediate early gene product Fos in the brain. Determining which of these actions are dependent on galanin receptors (versus a putative GALP-specific receptor), as well as which actions represent the authentic physiology of endogenous GALP will require continued experimentation. GALP gene expression is positively regulated by several hormones involved in the control of energy balance and metabolism, namely leptin, insulin and thyroid hormone. Based on current evidence, GALP neurones may serve as a hypothalamic relay, transmitting information from the periphery to circuits within the brain involved in the physiological control of metabolism and reproduction.

Predicting psychrometric conditions in biocontaminant microenvironments with a microclimate heat and moisture transfer model -- description and field comparison

A numerical model is described that is designed to model psychrometric conditions in biocontaminant microenvironments, such as in bedding and the base of carpets for dust-mites, and on the surface of linings for molds. The model is very general and can include room air, other room components, other zones including the outdoors, other rooms and any subfloor space. Mechanical plant can be modeled. Good agreement between modeled and field results are reported for the complex case of an occupied bed and for the microclimate in the base of a carpet, before and after its timber floor above a crawl space was retrofitted with insulation.

PRACTICAL IMPLICATIONS

Biocontaminants such as dust-mites and molds can pose serious health problems. Understanding microclimates in biocontaminant microhabitats, when coupled with biologic models, will make it possible to predict how the life cycles of these biocontaminants are affected as these conditions change. In turn, this will suggest which interventions that modify indoor climate and microclimate are likely to control these biocontaminants. Furthermore such interventions might include indoor humidity control, changing building insulation and ventilation levels, covering mattresses, use of electric blankets, use of carpet heating, etc. Such models will provide a fast way for screening for interventions that are likely to be effective in the control of biocontaminants.

Complications of beta-thalassemia major in North America

Treatment of patients with beta-thalassemia major has improved dramatically during the past 40 years; however, the current clinical status of these patients remains poorly characterized. We performed a cross-sectional study of 342 patients in the Registry of the National Institutes of Health-sponsored Thalassemia Clinical Research Network. Evidence of hepatitis C exposure was present in 35% of tested patients, was associated with age, and had a rate of spontaneous viral clearance of 33%. Ferritin levels ranged from 147 to 11 010 ng/mL (median, 1696 ng/mL). Median hepatic iron content was 7.8 mg/g dry weight and 23% of patients had values of 15 mg/g dry weight or higher. No patients 15 years or younger and 5% of patients aged 16 to 24 years had heart disease requiring medication. Ten percent had cirrhosis on biopsy. Endocrinologic complications were common among adults. Seventy-four (22%) patients had recent implantable central venous access devices (CVADs) placed. Among 80 episodes of bacteremia in 38 patients, 90% were attributable to the CVAD. Among 330 patients who had received deferoxamine chelation therapy, 224 (68%) reported no complications. We conclude that hepatitis C, iron-related organ dysfunction, and complications of iron chelation therapy are strongly age-dependent in North American patients with beta-thalassemia.

Thalassemia

New developments in the epidemiology, treatment and prognosis of thalassemia have dramatically altered the approach to the care of affected patients, and these developments are likely to have an even greater impact in the next few years. Demographic changes have required an awareness and understanding of the unique features of thalassemia disorders that were previously uncommon in North America but are now seen more frequently in children and recognized more consistently in adults. New methods for measuring tissue iron accumulation and new drugs to remove excessive iron are advancing two of the most challenging areas in the management of thalassemia as well as other transfusion-dependent disorders. Improved survival of patients with thalassemia has given new importance to adult complications such as endocrinopathies and hepatitis that have a major impact on the quality of life. This chapter describes how these changes are redefining the clinical management of thalassemia.

In Section I, Dr. Renzo Galanello describes recent advances in iron chelation therapy. Several new chelators are either licensed in some countries, are in clinical trials or are in the late stages of preclinical development. Some of these iron chelators, such as deferiprone (DFP) and ICL670, are orally active. Others, such as hydroxybenzyl-ethylenediamine-diacetic acid (HBED) and starch deferoxamine, require parenteral administration but may be effective with less frequent administration than is currently required for deferoxamine. Chelation therapy employing two chelators offers the possibility of more effective removal of iron without compromising safety or compliance. Other strategies for chelation therapy may take advantage of the ability of particular chelators to remove iron from specific target organs such as the heart and the liver.

In Section II, Dr. Dudley Pennell addresses cardiac iron overload, the most frequent cause of death from chronic transfusion therapy. The cardiac complications related to excessive iron may result from long-term iron deposition in vulnerable areas or may be due to the more immediate effects of nontransferrin-bound iron. Cardiac disease is reversible in some patients with intensive iron chelation therapy, but identification of cardiac problems prior to the onset of serious arrhythmias or congestive heart failure has proven difficult. New methods using magnetic resonance imaging (MRI) have recently been developed to assess cardiac iron loading, and studies suggest a clinically useful relationship between the results using these techniques and critical measures of cardiac function. Measurements such as T2* may help guide chelation therapy in individual patients and may also enhance the assessment of new chelators in clinical trials. The use of MRI-based technology also holds promise for wider application of non-invasive assessment of cardiac iron in the management of patients with thalassemia.

In Section III, Dr. Melody Cunningham describes some of the important complications of thalassemia that are emerging as patients survive into adulthood. Hepatitis C infection is present in the majority of patients older than 25 years. However, antiviral therapy in patients with thalassemia has been held back by the absence of large clinical trials and concern about ribavirin-induced hemolysis. More aggressive approaches to the treatment of hepatitis C may be particularly valuable because of the additive risks for cirrhosis and hepatocellular carcinoma that are posed by infection and iron overload. Thrombosis is recognized with increasing frequency as a significant complication of thalassemia major and thalassemia intermedia, and pulmonary hypertension is now the focus of intense study. Risk factors for thrombosis such as splenectomy are being identified and new approaches to anticoagulation are being initiated. Pregnancies in women with thalassemia are increasingly common with and without hormonal therapy, and require a better understanding of the risks of iron overload and cardiac disease in the mother and exposure of the fetus to iron chelators.

In Section IV, Dr. Elliott Vichinsky describes the dramatic changes in the epidemiology of thalassemia in North America. Hemoglobin E-β thalassemia is seen with increasing frequency and poses a particular challenge because of the wide variability in clinical severity. Some affected patients may require little or no intervention, while others need chronic transfusion therapy and may be appropriate candidates for hematopoietic stem cell transplantation. Enhancers of fetal hemoglobin production may have a unique role in Hb E-β thalassemia since a modest increase in hemoglobin level may confer substantial clinical benefits. Alpha thalassemia is also being recognized with increasing frequency in North America, and newborn screening for Hemoglobin Barts in some states is leading to early detection of Hb H disease and Hb H Constant Spring. New data clarify the importance of distinguishing these two disorders because of the increased severity associated with Hb H Constant Spring. The use of intrauterine transfusions to sustain the viability of fetuses with homozygous alpha thalassemia has created a new population of patients with severe thalassemia and has raised new and complex issues in genetic counseling for parents with alpha thalassemia trait.

Regulation of galanin-like peptide gene expression by pituitary hormones and their downstream targets

Galanin-like peptide (GALP) mRNA is expressed in neurones of the hypothalamic arcuate nucleus and within pituicytes in the neurohypophysis. Several neuropeptides that are expressed in the arcuate nucleus participate in the neuroendocrine regulation of pituitary hormone secretion. Our objective was to determine the extent to which GALP might be a target for regulation by pituitary hormones or their downstream targets in the rat. The expression of GALP mRNA in the arcuate nucleus was reduced by hypophysectomy as determined by in situ hybridization. However, this did not appear to be attributable to the loss of either gonadal or adrenal steroids because castrated, ovariectomized and adrenalectomized rats had GALP mRNA expression that was indistinguishable from their respective controls. Next, we investigated the effects of growth hormone deficiency on GALP mRNA expression by studying dwarf rats and found that GALP gene expression was not different between dwarf rats and controls. We found that thyroidectomy led to a significant reduction in GALP mRNA expression compared to intact controls, and thyroidectomized rats implanted with thyroxine pellets had GALP mRNA expression that was similar to intact controls. Thus, the reduction of GALP mRNA expression seen in hypophysectomized animals may reflect, in part, a selective loss of thyroid hormone. We also found that the expression of GALP mRNA was increased in the neurohypophysis of lactating rats compared to nonlactating rats, whereas GALP mRNA expression in the arcuate nucleus was unaffected by lactation. This suggests that the induction of GALP gene expression in pituicytes is physiologically associated with activation of oxytocin and vasopressin secretion during lactation.

Distribution and regulation of galanin-like peptide (GALP) in the hypothalamus of the mouse

Galanin-like peptide (GALP) is a newly discovered molecule whose expression in the brain is confined to the arcuate nucleus and median eminence. In the rat, cellular levels of GALP mRNA are reduced by fasting and reversed by peripheral administration of leptin. The purpose of this investigation was 1) to clone and map the distribution of GALP mRNA in the brain of the mouse; 2) to compare the pattern and magnitude of GALP mRNA expression in the leptin-deficient obese (ob/ob) mouse with that of wild-type controls; and 3) to examine the effects of leptin delivered into the brain on the expression of GALP mRNA in the ob/ob mouse. We report the sequence of a mouse GALP cDNA and show that GALP mRNA is expressed in the arcuate nucleus, median eminence, infundibular stalk, and the neurohypophysis of this species. The expression of GALP mRNA in the brain was markedly reduced in the ob/ob mice, compared with wild-type animals. Intracerebroventricular infusion of leptin to ob/ob mice increased both the number of GALP mRNA-expressing neurons and their content of GALP mRNA, compared with vehicle-treated controls. These observations demonstrate that GALP mRNA is induced by leptin through a direct action on the brain.

Gene expression microarray data analysis for toxicology profiling

When dealing with thousands of genes, all potentially interesting, it is desirable to rank the genes according to their degree of participation in a physiological process. Therefore, genes with the highest Shannon entropy and ERL can be selected as the best toxicity target candidates, permitting preclinical scientists to focus their research and resources on those genes.

Serotonergic neurons are targets for leptin in the monkey

Leptin is a secretory product of adipocytes that has been shown to affect food intake, metabolism, and reproduction. One site of leptin's action is the central nervous system, where the leptin receptor (Ob-R) messenger ribonucleic acid (mRNA) and protein are expressed in discrete areas. In both the rat and monkey, Ob-R mRNA has been localized in the Raphe nuclei of the brainstem. Neurons in the Raphe nuclei are the primary source of serotonin in the brain. Serotonergic pathways influence both feeding and reproduction, and these cells are plausible direct targets for leptin's action. We used double label in situ hybridization and computerized image analysis to determine whether serotonergic neurons in the brainstem of the female pigtailed macaque (Macaca nemestrina) express Ob-R mRNA. We observed that many cells in the Raphe nuclei express serotonin transporter mRNA, a marker of serotonergic cells, and Ob-R mRNA. Based on quantitative analysis, the highest number of cells that express both serotonin transporter and Ob-R mRNAs were found in the caudal dorsal Raphe and median Raphe nuclei; fewer double labeled cells were situated in the caudal linear nucleus and rostral median Raphe, whereas double labeled cells occurred infrequently in the rostral dorsal Raphe. These observations suggest that leptin may act on serotonergic cells to mediate some of its effects on ingestive behavior, metabolism, and reproduction.

The health impact of chronic recurrent rhinosinusitis in children

OBJECTIVES

To report and quantify the health-related quality of life of children who require surgical intervention for chronic recurrent rhinosinusitis and to assess the perspective of the child vs that of the parent.

DESIGN

Prospective, observational.

PATIENTS AND INTERVENTION

Twenty-one of a consecutive sample of 35 children undergoing endoscopic sinus surgery for infectious indications completed, along with their parents, the Child Health Questionnaire. The Child Health Questionnaire measures in parallel both child and parent perceptions of health by means of separate parent proxy report (Child Health Questionnaire-Parent Form 50) and child self-report (Child Health Questionnaire-Child Form 87) questionnaires concerning physical and psychosocial functioning.

MAIN OUTCOME MEASURES

Tabulated scores from both the Child Health Questionnaire-Parent Form 50 and Child Health Questionnaire-Child Form 87 were compared with published data from age-matched normative populations and several pediatric chronic disease groups.

RESULTS

Significant decrements in the general health of children with chronic recurrent rhinosinusitis compared with a normative sample were observed for both child- and parent-reported data, particularly in the physical domains. Children with rhinosinusitis were perceived by their parents to have significantly more bodily pain (P<.001)and to be more limited in their physical activities (P<.05)than children with asthma, juvenile rheumatoid arthritis, and other chronic disorders. Parent-child perceptions did vary, with parents reporting more pain and general behavioral effects relative to their children's reports in these areas.

CONCLUSION

The health impact of chronic recurrent rhinosinusitis as reported by the subjective evaluations of pediatric patients and their parents is severe.

An unusual pterygopalatine meningocele associated with neurofibromatosis type 1. Case report

The authors describe an unusual meningocele of the lateral wall of the cavernous sinus and the anterior skull base in a young patient with typical stigmata of neurofibromatosis Type 1 (NF1). This lesion was discovered during evaluation for recurrent meningitis. It represented an anterior continuation of Meckel's cave into a large cerebrospinal fluid space within the lateral wall of the cavernous sinus, extending extracranially through an enlarged superior orbital fissure into the pterygopalatine fossa adjacent to the nasal cavity. It was successfully obliterated, via an intradural middle fossa approach, with fat packing and fenestration into the subarachnoid space. This meningocele most likely represents a variant of cranial nerve dural ectasia occasionally seen in individuals with NF1. It has as its basis the same mesodermal defect responsible for the more common sphenoid wing dysplasia and spinal dural ectasias identified with this condition. Involvement of the trigeminal nerve with expansion of the lateral wall of cavernous sinus has not been reported previously. The authors surmise, however, that it may be present in some cases of orbital meningocele associated with sphenoid wing dysplasia.

Cytokeratin expression in the odontogenic keratocyst

PURPOSE

This study attempted to identify differential cytokeratin expression in cystic jaw lesions using immunohistochemical staining.

PATIENTS AND METHODS

The charts from selected patients treated between 1983 and 1994 for jaw cysts were evaluated. Twenty-four paraffinized specimens were selected randomly for investigation with 5 immunohistochemical stains. The 4 diagnostic categories included ameloblastoma, dentigerous cyst, odontogenic keratocyst (OKC), and recurrent odontogenic keratocyst in patients with nevoid basal cell carcinoma (NBCC) syndrome. The 5 immunohistochemical stains included antibodies to cytokeratins 13, 17, and 18; CAM 5.2; AE 1/3; and carcinoembryonic antigen (CEA).

RESULTS

Differential staining of OKCs from patients with and without NBCC syndrome was found only with the antibody to cytokeratin 17. Furthermore, staining of OKCs in syndromic patients appeared to be stronger and more uniform than in nonsyndromic patients.

CONCLUSIONS

These findings suggest that immunohistochemical staining for cytokeratin 17 may aid in the diagnosis of OKCs and may be used to further subdivide these lesions based on the presence or absence of NBCC syndrome.

Genomics and proteomics: the new millennium of drug discovery and development

One of the most pressing issues facing the pharmaceutical and biotechnology industry is the tremendous dropout rate of lead drug candidates. Over the last two decades, several new genomic technologies have been developed in hopes of addressing the issues of target identification and lead candidate optimization. Gene expression microarray is one of these technologies and this review describes the four main formats, which are currently available: (a) cDNA; (b) oligonucleotide; (c) electrokinetic; and (d) fiberoptic. Many of these formats have been developed with the goal of screening large numbers of genes. Recently, a high-throughput array format has been developed where a large number of samples can be assayed using arrays in parallel. In addition, focusing on gene expression may be only one avenue in preventing lead candidate failure. Proteomics or the study of protein expression may also play a role. Two-dimensional polyacrylamide gel electrophoresis (2-DE) coupled with mass spectroscopy has been the most widely accepted format to study protein expression. However, protein microarrays are now being developed and modified to a high-throughput screening format. Examples of several gene and protein expression studies as they apply to drug discovery and development are reviewed. These studies often result in large data sets. Examples of how several statistical methods (principal components analysis [PCA], clustering methods, Shannon entropy, etc.) have been applied to these data sets are also described. These newer genomic and proteomic technologies and their analysis and visualization methods have the potential to make the drug discovery and development process less costly and more efficient by aiding to select better target and lead candidates.

Galanin-like peptide (GALP) is a target for regulation by leptin in the hypothalamus of the rat

Galanin-like peptide (GALP), which was recently isolated from the porcine hypothalamus, shares sequence homology with galanin and binds with high affinity to galanin receptors. To study the distribution and regulation of GALP-expressing cells in the brain, we cloned a 120 base-pair cDNA fragment of rat GALP and produced an antisense riboprobe. In situ hybridization for GALP mRNA was then performed on tissue sections throughout the forebrain of adult ovariectomized female rats. We found GALP mRNA-containing cells in the arcuate nucleus (Arc), caudal dorsomedial nucleus, median eminence and the pituitary. Because GALP mRNA in the Arc appeared to overlap with the known distribution of leptin receptor mRNA, we tested the hypothesis that GALP expression is regulated by leptin. Using in situ hybridization, we compared the number of GALP mRNA-containing cells among groups of rats that were fed ad lib or fasted for 48 h and treated with either leptin or vehicle. Fasting reduced the number of identifiable cells containing GALP mRNA in the Arc, whereas the treatment of fasted animals with leptin produced a 4-fold increase in the number of cells expressing GALP message. The presence of GALP mRNA in the hypothalamus and pituitary and its regulation by leptin suggests that GALP may have important neuroendocrine functions, including the physiological regulation of feeding, metabolism, and reproduction.

Physician experience with an optical image guidance system for sinus surgery

OBJECTIVES/HYPOTHESIS

Intraoperative guidance systems have been developed which use infrared tracking technology to assist with anatomical localization during sinus surgery. Although the introduction of this technology is intended to increase the safety and efficacy of sinus surgery, little is known about its actual impact in the clinical setting. The objective of this report was to study the application and utilization of an image guidance system shared by multiple sinus surgeons in a specialty hospital.

STUDY DESIGN

Combined prospective case study and retrospective analysis of physician surveys.

METHODS

An optical-based image guidance system (LandmarX, Xomed, Inc., Jacksonville, FL) was used by 34 physicians to perform 754 sinonasal surgeries over a 2.5-year period at Massachusetts Eye and Ear Infirmary. In 19 cases, system registration was repeated during surgery to measure the effect of fiducial placement on system accuracy.

RESULTS

The measured accuracy of anatomical localization at the start of surgery (mean value, 1.69 +/- 0.38 mm) was comparable to the perceived accuracy of 1 to 3 mm that was reported by 79% of surgeons surveyed. Operating room time (mean period, 130.6 +/- 41.1 min) correlated with the surgical procedure performed (P < .05), but not with the disease stage or revision rate. According to a majority of surgeons, use of the image guidance equipment increased operating room time by 15 to 30 minutes during initial cases and by 5 to 15 minutes once experience with the equipment had been acquired. More than 90% of surgeons anticipated their continued use of the image guidance equipment for sinus surgery at a similar or greater level in the future.

CONCLUSION

An optical-based image guidance system can be successfully integrated into a multisurgeon operating room environment. Use of the system provides accurate anatomical localization during sinus surgery and results in a relatively high level of physician satisfaction.

Impact of tympanostomy tubes on child quality of life

BACKGROUND

The objective benefits of tympanostomy tubes for otitis media are well established, but the subjective impact of surgery on child quality of life (QOL) has not been systematically studied.

OBJECTIVES

To determine the subjective impact of tympanostomy tubes on child QOL, and to compare the variability in QOL before surgery with that observed after surgery.

DESIGN

Prospective, observational, before-and-after trial.

SETTING

Fourteen referral-based pediatric otolaryngology practices in the United States.

PATIENTS

Consecutive (64%) and convenience (36%) sample of 248 children (median age, 1.4 years) with otitis media scheduled for bilateral tympanostomy tube placement as an isolated surgical procedure.

INTERVENTION

Tympanostomy tubes were inserted as part of routine clinical care. Validated measures of QOL (OM-6 survey), satisfaction with health care decision (Satisfaction With Decision Scale), and satisfaction with office visit; surveys were completed at baseline (visit 1), at surgery (visit 2), and after surgery (visit 3).

MAIN OUTCOME MEASURES

Short-term changes in QOL before surgery (visit 1 to visit 2) and after surgery (visit 2 to visit 3).

RESULTS

Changes in QOL before surgery were mostly trivial, and were smaller than changes observed after surgery (P<.001). Large, moderate, and small improvements in QOL occurred after surgery in 56%, 15%, and 8% of children, respectively. Physical symptoms, caregiver concerns, emotional distress, and hearing loss were most improved, but significant changes were also seen for activity limitations and speech impairment. Trivial changes occurred in 17% of children, and 4% had poorer QOL. Predictors of poorer QOL were otorrhea 3 or more days (10% of variance) and decreased satisfaction with surgical decision (3% of variance). Hearing status, child age, type of otitis media (recurrent vs chronic), and office visit satisfaction were unrelated to outcome.

CONCLUSIONS

Tympanostomy tubes produce large short-term improvements in QOL for most children. The best outcomes occur when postoperative otorrhea is absent or minimal, and when parents are satisfied with their initial decision to have surgery. Further research is needed to document the long-term impact of tubes on child QOL.

The application of shannon entropy in the identification of putative drug targets

A major challenge in the field of functional genomics is the development of computational techniques for organizing and interpreting large amounts of gene expression data. These methods will be critical for the discovery of new therapeutic drug targets. Here, we present a simple method for determining the most likely drug target candidates from temporal gene expression patterns assayed with reverse-transcription polymerase chain reaction (RT-PCR) and DNA microarrays.

Galanin's functional significance in the regulation of the neuroendocrine reproductive axis of the monkey

Galanin stimulates the neuroendocrine reproductive axis in the rat, but whether galanin acts similarly in primate species is unknown. To test the hypothesis that galanin acts within the hypothalamo-hypophyseal axis to stimulate luteinizing hormone (LH) and gonadotropin-releasing hormone (GnRH) secretion in the primate, galanin was administered either systemically or directly into the arcuate nucleus-median eminence of ovariectomized macaques (pigtailed or rhesus, respectively) that were maintained on estradiol. The mean plasma levels of LH were significantly elevated in pigtailed macaques after peripheral injection of galanin (2 mg) as compared with vehicle treatment. In rhesus monkeys, galanin (80 microM) administered by push-pull perfusion into the arcuate nucleus-median eminence did not significantly alter either GnRH or LH release. To determine whether in the monkey, as in the rat, subpopulations of medial forebrain GnRH neurons coexpress galanin mRNA, we used single- and double-label in situ hybridization and computerized imaging techniques. GnRH mRNA-containing cells were identified in both the medial and lateral forebrain of the female pigtailed macaque. No galanin mRNA expression was detectable in GnRH neurons located in either the medial preoptic area or mediobasal hypothalamus; however, within the substantia innominata a subset of GnRH mRNA-expressing neurons did coexpress galanin mRNA. Taken together, these results suggest that galanin induces LH release in primates, but galanin may not act directly on hypothalamic GnRH neurons. Presently, we have confirmed in another primate species the existence of GnRH gene expression in the lateral forebrain and discovered that a small subset of these neurons coexpress galanin. These particular cells may have a unique and as of yet undefined physiological function that is distinct from those GnRH neurons serving a hypophysiotropic function.

The effect of a modified physical training program in reducing injury and medical discharge rates in Australian Army recruits

This uncontrolled observational study examined the injury and medical discharge outcomes in 318 female and 1,634 male recruits as a result of changes to the Australian Army recruit physical training program. Changes included cessation of road runs, introduction of 400- to 800-m interval training, reduction in test run distance from 5 to 2.4 km, standardization of route marches, and the introduction of deep-water running. There was a 46.6% reduction in the rate of total injury presentation (chi 2 = 14.31, p = 0.0002) after the change. The annual rate of male medical discharges decreased 40.8% from 81.1/1,000 recruits in 1994/1995 to 47.0/1,000 recruits in 1995/1996 (chi 2 = 26.33, p = 0.0001). Female rates increased 58.3% from 104/1,000 recruits to 164.2/1,000 recruits (chi 2 = 6.09, p = 0.014). The decrease in the male medical discharge rate resulted in an estimated saving of $1,267,805 Australian. Bone scans were reduced by 50%, resulting in an estimated annual saving of $61,539 Australian. The disparity between male and female injury rates is a concern. The merits of mixed-gender physical training should be reviewed in the light of these observations, and the establishment of initial entry fitness standards for recruit training may need to be considered.

Rigid tracheobronchoscopy-induced bacteremia in the pediatric population

OBJECTIVE

To assess the incidence of bacteremia following rigid tracheobronchoscopy in children to determine whether use of prophylactic antibiotics is warranted in pediatric patients at risk for perioperative endocarditis.

DESIGN

Prospective nonrandomized clinical study.

SETTING

Specialty care referral center.

PATIENTS

Patients younger than 18 years undergoing diagnostic rigid tracheobronchoscopy for airway assessment. Twenty-five patients (14 boys and 11 girls) were enrolled. The mean age was 5.2 years (range, 10 months to 13 years).

INTERVENTIONS

Blood samples for culture were obtained intraoperatively at 2 time intervals. The first culture was obtained after the induction of mask anesthesia prior to airway instrumentation; the second, within 5 minutes following the completion of tracheobronchoscopy. Blood cultures were performed under sterile technique and were placed into 20 mL of brain heart infusion broth. All cultures were incubated at 35 degrees C and observed for growth over a 14-day period.

RESULTS

There were no documented cases of bacterial growth in blood cultures. All blood cultures, obtained before and after tracheobronchoscopy, were negative for bacterial growth after incubation for 14 days. Two culture bottles yielded contaminant organisms.

CONCLUSIONS

Rigid tracheobronchoscopy in the pediatric population is a low-risk procedure for the development of bacteremia. This may bear on present guidelines regarding perioperative antibiotic prophylaxis for endocarditis in the high-risk population.

Immune response to pneumococcal conjugate and polysaccharide vaccines in otitis-prone and otitis-free children

We compared responses to pneumococcal conjugate and polysaccharide vaccines in 48 otitis-free and 64 otitis-prone children. Pre- and postimmunization concentrations of antibodies to pneumococcal serotypes 6B, 14, 19F, and 23F were measured by enzyme-linked immunosorbent assay. Postimmunization mean concentrations of antibodies to all four serotypes were significantly higher for children receiving conjugate vaccine than for those receiving polysaccharide vaccine; the difference in responses was primarily due to a better response to conjugate vaccine in the otitis-prone group. Significantly higher postimmunization concentrations of antibodies to all four serotypes and to one of the four serotypes were found in otitis-prone children and otitis-free children who received conjugate vaccine, respectively. Pneumococcal conjugate vaccine has the potential to reduce the incidence of disease due to vaccine serotypes, even among children with recurrent otitis media.

A multidisciplinary approach to atypical lacrimal obstruction in childhood

PURPOSE

This study explores the diagnosis and management of unusual anomalies involving the canaliculi, nasolacrimal duct, nasal cavity, and sinuses in childhood.

METHODS

A case series of eight children with lacrimal outflow anomalies ranging from distal nasolacrimal duct cyst formation to persistent dacryocystitis following failed probing or silicone intubation were reviewed retrospectively. Diagnostic studies including intranasal endoscopy and preoperative or intraoperative dacryocystography (DCG) were of value.

RESULTS

Treatment modalities included endoscopically guided resection of lacrimal cyst mucosa, endoscopic dacryocystorhinostomy (DCR), and monocanalicular or bicanalicular intubation of the lacrimal outflow system. In our series, endoscopic surgery was well tolerated by all patients with improvement in symptoms.

CONCLUSIONS

This initial experience suggests that endoscopic techniques may be useful in the management of atypical lacrimal outflow obstruction in childhood.

Leptin's actions on the reproductive axis: perspectives and mechanisms

Energy availability influences reproductive fitness. The activity of the reproductive axis is sensitive to the adequacy of nutrition and the stores of metabolic reserves. The adipocyte-derived hormone leptin is postulated to reflect the state of nutrition and energy reserves and serve as a metabolic gate to the reproductive system. Genetically obese ob/ob mice (lacking endogenous leptin) are infertile, and treatment of these animals with exogenous leptin stimulates the activity of the reproductive endocrine system and induces fertility in both sexes. Severely food-restricted animals have reduced circulating levels of leptin, which are associated with markedly reduced secretion of the gonadotropins, LH, and FSH. Treatment of food-restricted mice, rats, sheep, and monkeys with exogenous leptin reverses the diet-induced inhibition of gonadotropin secretion. Leptin has also been suggested to have a role in timing the onset of puberty in several species, although evidence that leptin is the primary metabolic signal for initiating the onset of puberty in any species is controversial. Notwithstanding this debate, it is undisputed for all species studied to date that adequate levels of leptin in the circulation are essential (but not sufficient) for pubertal progression and that leptin treatment can reverse the delay in sexual maturation caused by food restriction. Double-label in situ hybridization studies in the brain of the mouse, rat, and monkey have revealed that hypothalamic neurons expressing proopiomelanocortin and neuropeptide Y coexpress the leptin receptor, whereas no evidence has been adduced that GnRH neurons express this receptor. Together, these observations suggest that leptin is a metabolic signal to the neuroendocrine reproductive system and that under conditions of inadequate energy reserves, low leptin levels act as a metabolic "gate" to inhibit the activity of the neuroendocrine reproductive axis in both sexes.

Mutations in the gene encoding B1 subunit of H+-ATPase cause renal tubular acidosis with sensorineural deafness

H+-ATPases are ubiquitous in nature; V-ATPases pump protons against an electrochemical gradient, whereas F-ATPases reverse the process, synthesizing ATP. We demonstrate here that mutations in ATP6B1, encoding the B-subunit of the apical proton pump mediating distal nephron acid secretion, cause distal renal tubular acidosis, a condition characterized by impaired renal acid secretion resulting in metabolic acidosis. Patients with ATP6B1 mutations also have sensorineural hearing loss; consistent with this finding, we demonstrate expression of ATP6B1 in cochlea and endolymphatic sac. Our data, together with the known requirement for active proton secretion to maintain proper endolymph pH, implicate ATP6B1 in endolymph pH homeostasis and in normal auditory function. ATP6B1 is the first member of the H+-ATPase gene family in which mutations are shown to cause human disease.

The treatment of gastric mucosal prolapse syndrome with laparoscopic nissen fundoplication

Gastric mucosal prolapse occurs when a portion of the mucosa of the stomach herniates into the esophagus, resulting in massive hemorrhage. A 19-year-old man presented on two occasions with an upper gastrointestinal hemorrhage as a result of this syndrome. He was definitively treated with a laparoscopic Nissen fundoplication. This case report outlines his presentation, defines and details gastric mucosal prolapse, and discusses the treatment of this syndrome with laparoscopic Nissen fundoplication.

The stimulatory effect of leptin on the neuroendocrine reproductive axis of the monkey

Leptin acts as a metabolic activator of the neuroendocrine reproductive axis in several rodent species, but whether leptin plays a similar role in primates is unknown. To explore this question, we examined the effects of leptin on gonadotropin and testosterone secretion in male rhesus monkeys that were fasted for 2 days. Mean plasma levels of LH and FSH, LH pulse frequency, and LH pulse amplitude were significantly higher in leptin-treated animals compared with saline-treated controls during the second day of the fast. To identify targets for leptin's action, we used in situ hybridization and computerized imaging to map leptin receptor (Ob-R) messenger RNA (mRNA) distribution. Ob-R mRNA was observed in the anterior pituitary and several areas of the brain, including the arcuate and ventromedial nuclei of the hypothalamus. Ob-R mRNA was coexpressed in both POMC and neuropeptide Y neurons in the arcuate nucleus, whereas little or no coexpression of Ob-R mRNA was evident in GnRH neurons. These results suggest that leptin is a metabolic signal to the reproductive axis in primates and imply that both POMC and neuropeptide Y neurons are involved in mediating leptin's effects in the brain.

Direct measurements of temperature and humidity in dust mite microhabitats

BACKGROUND

Up to 70% of atopic asthmatics have a positive skin test to the dust mite allergen Der p 1. Reduction of dust mite numbers by lowering room humidity control is one suggested technique for reducing dust mite allergen levels to clinically acceptable levels. Trials of this technique in temperate climates have reported mixed results. It has been speculated that one reason for this is that humidity changes in room ambient air are not tightly linked to humidity changes in the dust mite microenvironment (in the base of carpets, bedding, furniture etc.).

OBJECTIVE

To directly measure humidities and temperatures in dust mite microenvironments and compare these to ambient conditions, and so gather data on how the microclimates are influenced by room conditions and moisture and heat sources, such as an occupant in a bed.

METHODS

A special small humidity device has been developed which can discriminate humidity changes over distances of millimetres. With these devices microclimates have been measured in the base of carpets, in layers through bedding, and in furniture.

RESULTS

Measured base-of-carpet humidities were significantly higher than room humidities. Bedding relative humidities show complex behaviour according to the distance separation between the measuring point and the occupant. Immediately below the occupant, bed relative humidities fall when the person enters the bed. Similar behaviour is observed in a sofa.

CONCLUSION

Some dust mite microclimates have been shown to be very different from room conditions. Consequently, reduction of dust mite numbers and allergen levels cannot be guaranteed by the controlling of room humidities.

Mutations in the chloride-bicarbonate exchanger gene AE1 cause autosomal dominant but not autosomal recessive distal renal tubular acidosis

Primary distal renal tubular acidosis (dRTA) is characterized by reduced ability to acidify urine, variable hyperchloremic hypokalemic metabolic acidosis, nephrocalcinosis, and nephrolithiasis. Kindreds showing either autosomal dominant or recessive transmission are described. Mutations in the chloride-bicarbonate exchanger AE1 have recently been reported in four autosomal dominant dRTA kindreds, three of these altering codon Arg589. We have screened 26 kindreds with primary dRTA for mutations in AE1. Inheritance was autosomal recessive in seventeen kindreds, autosomal dominant in one, and uncertain due to unknown parental phenotype or sporadic disease in eight kindreds. No mutations in AE1 were detected in any of the autosomal recessive kindreds, and analysis of linkage showed no evidence of linkage of recessive dRTA to AE1. In contrast, heterozygous mutations in AE1 were identified in the one known dominant dRTA kindred, in one sporadic case, and one kindred with two affected brothers. In the dominant kindred, the mutation Arg-589/Ser cosegregated with dRTA in the extended pedigree. An Arg-589/His mutation in the sporadic case proved to be a de novo mutation. In the third kindred, affected brothers both have an intragenic 13-bp duplication resulting in deletion of the last 11 amino acids of AE1. These mutations were not detected in 80 alleles from unrelated normal individuals. These findings underscore the key role of Arg-589 and the C terminus in normal AE1 function, and indicate that while mutations in AE1 cause autosomal dominant dRTA, defects in this gene are not responsible for recessive disease.