Suppression of food intake by Glp1r/Lepr-coexpressing neurons prevents obesity in mouse models

The adipose-derived hormone leptin acts via its receptor (LepRb) in the brain to control energy balance. A potentially unidentified population of GABAergic hypothalamic LepRb neurons plays key roles in the restraint of food intake and body weight by leptin. To identify markers for candidate populations of LepRb neurons in an unbiased manner, we performed single-nucleus RNA-Seq of enriched mouse hypothalamic LepRb cells, identifying several previously unrecognized populations of hypothalamic LepRb neurons. Many of these populations displayed strong conservation across species, including GABAergic Glp1r-expressing LepRb (LepRbGlp1r) neurons, which expressed more Lepr than other LepRb cell populations. Ablating Lepr from LepRbGlp1r cells provoked hyperphagic obesity without impairing energy expenditure. Similarly, improvements in energy balance caused by Lepr reactivation in GABA neurons of otherwise Lepr-null mice required Lepr expression in GABAergic Glp1r-expressing neurons. Furthermore, restoration of Glp1r expression in LepRbGlp1r neurons in otherwise Glp1r-null mice enabled food intake suppression by the GLP1R agonist, liraglutide. Thus, the conserved GABAergic LepRbGlp1r neuron population plays crucial roles in the suppression of food intake by leptin and GLP1R agonists.

"It was my obligation as mother": 18-Month completion of Early Infant Diagnosis as identity control for mothers living with HIV in Kenya

RATIONALE

Early Infant Diagnosis (EID) is critical to timely identification of HIV and rapid treatment initiation for infants found to be infected. Completing the EID cascade involves a series of age-specific tests between birth and 18 months and can be challenging for mother- infant pairs in low-resource settings. Even prior to recent increases in Kenya's testing recommendations, approximately 22% of mother-infant pairs enrolled in EID were lost to follow-up. As EID cascades become increasingly complex, identifying strategies to maximize retention becomes even more essential. Despite ongoing health system improvements, we still lack a framework for understanding the individual-level, psychosocial processes underlying EID completion-insight that could be essential for shaping strategies to support patients and close gaps in retention.

OBJECTIVE

Our objective was to explain individual-level processes that lead to EID completion among mothers who successfully completed the EID cascade.

METHODS

Using qualitative methods informed by grounded theory, we conducted 65 interviews with Kenyan mothers who completed EID.

RESULTS

We identified three themes related to completion: (1) Negative motivation, from the consequences of infant infection, fear of postnatal transmission, and burden of maternal failure; (2) Positive motivation, from achieving a final goal, responding to provider support, and maximizing infant health; and (3) Overcoming challenges, through resolve/resiliency, planning/privatizing and rejecting stigma/leveraging support.

CONCLUSION

Overall, the EID cascade served as a framing process for women to secure an identity as a good mother. Successful EID completion was the product of a strong motivational foundation channeled into strategies to surmount persistent challenges. Participant accounts of overcoming challenges highlight their resiliency as well as the outstanding need to address financial, logistical, and social barriers to care. Future EID programs may capitalize on these findings by affirming patients' quest for identity control, leveraging positive motivators, and expanding peer support structures to help mothers feel connected throughout the cascade.

Defining the Transcriptional Targets of Leptin Reveals a Role for Atf3 in Leptin Action

Leptin acts via its receptor (LepRb) to modulate gene expression in hypothalamic LepRb-expressing neurons, thereby controlling energy balance and glucose homeostasis. Despite the importance of the control of gene expression in hypothalamic LepRb neurons for leptin action, the transcriptional targets of LepRb signaling have remained undefined because LepRb cells contribute a small fraction to the aggregate transcriptome of the brain regions in which they reside. We thus employed translating ribosome affinity purification followed by RNA sequencing to isolate and analyze mRNA from the hypothalamic LepRb neurons of wild-type or leptin-deficient (Lepob/ob) mice treated with vehicle or exogenous leptin. Although the expression of most of the genes encoding the neuropeptides commonly considered to represent the main targets of leptin action were altered only following chronic leptin deprivation, our analysis revealed other transcripts that were coordinately regulated by leptin under multiple treatment conditions. Among these, acute leptin treatment increased expression of the transcription factor Atf3 in LepRb neurons. Furthermore, ablation of Atf3 from LepRb neurons (Atf3LepRbKO mice) decreased leptin efficacy and promoted positive energy balance in mice. Thus, this analysis revealed the gene targets of leptin action, including Atf3, which represents a cellular mediator of leptin action.

Primary meningococcal arthritis as a presentation of nodal marginal zone lymphoma

A 68-year-old man presented with a 4-day history of worsening knee and arm pain. On examination, there was erythema and swelling of the left knee and both wrists. Joint aspiration grew Neisseria meningitidis Blood tests showed an unusually high total protein level (100 g/L) and an IgM kappa paraprotein band of 45 g/L on protein electrophoresis. CT showed widespread lymphadenopathy, hepatosplenomegaly and multilevel thoracic vertebral collapse. A bone marrow biopsy revealed a lymphoplasmacytic infiltrate and a lymph node biopsy showed features of nodal marginal zone lymphoma with plasmacytic differentiation.

ERα in Tac2 Neurons Regulates Puberty Onset in Female Mice

A variety of data suggest that estrogen action on kisspeptin (Kiss1)-containing arcuate nucleus neurons (which coexpress Kiss1, neurokinin B (the product of Tac2) and dynorphin (KNDy) neurons restrains reproductive onset and function, but roles for estrogen action in these Kiss1 neurons relative to a distinct population of rostral hypothalamic Kiss1 neurons (which does not express Tac2 or dynorphin) have not been directly tested. To test the role for estrogen receptor (ER)α in KNDy cells, we thus generated Tac2(Cre) and Kiss1(Cre) knock-in mice and bred them onto the Esr1(flox) background to ablate ERα specifically in Tac2-expressing cells (ERα(Tac2)KO mice) or all Kiss1 cells (ERα(Kiss1)KO mice), respectively. Most ERα-expressing Tac2 neurons represent KNDy cells. Arcuate nucleus Kiss1 expression was elevated in ERα(Tac2)KO and ERα(Kiss1)KO females independent of gonadal hormones, whereas rostral hypothalamic Kiss1 expression was normal in ERα(Tac2)KO but decreased in ERα(Kiss1)KO females; this suggests that ERα in rostral Kiss1 cells is crucial for control of Kiss1 expression in these cells. Both ERα(Kiss1)KO and ERα(Tac2)KO females displayed early vaginal opening, early and persistent vaginal cornification, increased gonadotropins, uterine hypertrophy, and other evidence of estrogen excess. Thus, deletion of ERα in Tac2 neurons suffices to drive precocious gonadal hyperstimulation, demonstrating that ERα in Tac2 neurons typically restrains pubertal onset and hypothalamic reproductive drive.

Lactobacillus plantarum 299v Prevents Caspase-Dependent Apoptosis In Vitro

Selective microbes used as probiotics can enhance epithelial cell protection. We have previously shown that a Lactobacillus plantarum strain 299v (Lp299v) has the ability to induce mucin genes. In the current study, we utilized a cytokine model of inflammation in cell culture to study the modulation of apoptosis by this probiotic. HT-29 cells were pre-incubated with the Lp299v or L. plantarum strain adh- (Lpadh-), a non-adherent derivative of Lp299v. Cells were challenged with a mixture of cytokines (TNF-α, IFN-γ, and IL-1a) to imitate conditions of inflammation. To assess for cell death, we evaluated TUNEL, multi-caspase, and caspase-3 and caspase-7 activity assays. There was a marked decrease in apoptosis as measured by TUNEL(+) cells in samples pre-treated with Lp299v (18.7 ± 4.1%, p < 0.01) and Lpadh- (16.6 ± 3.2%, p < 0.05) prior to cytokine exposure when compared to cells (43.6 ± 6.2%) exposed to the cytokine mixture. Lp299v pre-incubation with HT-29 cells reduced caspase(+) cells in the multi-caspase activity assay (3.6 ± 0.6%, p < 0.05) compared to cells exposed to cytokines (68.9 ± 5.1%) whereas Lpadh- did not (46.8 ± 17.5%, p > 0.05). Similarly, caspase-3, caspase-7 activity was also reduced by Lp299v. Selected probiotics may confer an exogenous protective effect at the mucosal-luminal interface for intestinal epithelial cells via alteration of caspase-dependent apoptotic pathways.

Generation of a transgenic model to address regulation and function of the human neurokinin 1 receptor (NK1R)

We have generated mouse transgenic lines using yeast artificial chromosome (YAC) technology which demonstrate expression from the human NK1 receptor (NK1R) locus. We introduced a 380 kb fragment encompassing the human NK1R gene and flanking regions which we hoped would recapitulate the expected endogenous expression of the human gene. To visualise this expression the NK1 locus co-expresses the green fluorescence protein gene (GFP) under the control of an internal ribosome entry site (IRES) sequence. We have generated five mouse lines that express the human NK1 receptor gene with and without the marker gene. All the lines incorporating the marker gene appear to exhibit the same expression pattern in analysis of selected anatomical regions throughout the mouse. The lack of a human specific NK1R antibody determined that we could not distinguish between expression of the transgene and endogenous NK1R. Our analysis has shown transgene expression in brain areas known to express NK1R in human such as the hippocampus and caudate putamen. The majority of these cells were also positive for GFP fluorescence. These transgenic lines may prove a good pre-clinical model as drugs can be addressed against both the human receptor and modulators of its expression in vivo.

Graded Doses of Recombinant Interleukin-1β Induce Generalized Osteopenia in Rats without Altering Skeletal Growth and Joint Integrity

BACKGROUND

Whereas a primary role of interleukin-1beta (IL-1beta) in local bone remodelling and articular inflammation has been well established, the effect of prolonged systemic administration of this cytokine on total skeletal Ca, somatic growth and joint tissue has not yet been investigated.

METHODS

Five groups of 14 rats each, aged 7-8 weeks, had miniosmotic pumps (Alzet 200 microl) implanted and primed to release 100, 200, 500, 1,000 and 2,000 ng/kg/24 h of human recombinant IL-1beta (rIL-1beta) daily for 14 days. On days 0 and 14 total skeletal mineral content (BMC) was assessed by means of X-ray absorptiometry and vertebral and tibial growth was measured by computer-assisted radiometry. On the same days, blood was drawn and analyzed for rat growth hormone (rGH), insulin-like growth factor (IGF-1), and osteocalcin. Also 24-hour urine was collected for d-pyridinoline (dpd) determinations. Hind- and forepaw diameter as a parameter of joint inflammation was assessed using a micrometric calliper. Subsequently the animals were sacrificed and one tibia dissected for measurement of trabecular volume by computerized histomorphometry.

RESULTS

BMC decreased in a dose-dependent manner reaching significance at 1,000 and 2,000 ng/kg (p < 0.03 and 0.04) in close correlation with tibial trabecular volumes (r = 0.84; p < 0.02). Normal vertebral and tibial growth was recorded at all dosages. There was no evidence of joint involvement. Blood rGH and IGF-1 remained normal as did osteocalcin, the latter reflecting lack of osteoblast activation. In contrast dpd increased in a dose-dependent manner indicating enhanced bone matrix turnover.

CONCLUSION

It is concluded that graded infusions of supraphysiological doses of rIL-1beta capable of inducing osteopenia did not affect skeletal growth in the absence of articular reaction. This is in contrast with the experience recorded in experimental arthritis in which growth retardation, in addition to osteopenia, may be caused by factors other than circulating IL-1beta.

Glutathione peroxidase levels throughout normal pregnancy and in pre-eclampsia

OBJECTIVE

Evidence suggests that hemoglobin, in addition to its function as a carrier of oxygen, also serves to transport nitric oxide, as S-nitroso cysteine, from the lungs to the peripheral circulation, where it can be released. Glutathione peroxidase, besides being an important antioxidant, is known to catalyze the release of nitric oxide from smaller carrier molecules, and may play a role in the distribution of nitric oxide throughout the body. In light of these findings, we sought to determine whether glutathione peroxidase levels differed throughout gestation, and specifically between pre-eclamptic and normal women.

METHODS

A nested case-control study of women receiving routine prenatal care was conducted. Pre-eclampsia was defined by a blood pressure of at least 140 mmHg systolic and/or 90 mmHg diastolic as well as proteinuria > 300 mg/24 h or > 2+ by dipstick, both occurring on two occasions at least 6 h apart. Blood was collected in heparinized tubes and was then centrifuged in a clinical centrifuge for 10 min. Plasma was frozen promptly at -80 degrees C for later enzyme-linked immunosorbent assay (ELISA), with which plasma glutathione peroxidase was determined.

RESULTS

The maternal demographics of the pre-eclamptic and non-pre-eclamptic study groups did not significantly vary with respect to mean maternal age, gravidity, parity and gestational age at the time of delivery. The median maternal ages were 33 and 34 years, and the median gestational ages at the time of birth were 37.5 and 38.1 weeks, respectively. In evaluating the glutathione peroxidase levels of all patients across the three trimesters, we found that there was essentially no difference in mean levels (83.7, 81.0 and 89.5 ng/ml, respectively). There was no difference between the pre-eclamptic and non-pre-eclamptic patients, again stratified by trimester. A linear regression analysis indicated that the plasma glutathione peroxidase concentration did not correlate with gestational age or the presence of pre-eclampsia.

CONCLUSIONS

Plasma glutathione peroxidase expression is similar across all trimesters. There is no change in the glutathione peroxidase levels in pre-eclamptic patients.

Human vascular endothelial growth factor B: characterization of recombinant isoforms and generation of neutralizing monoclonal antibodies

1. The vascular endothelial growth factor (VEGF) family is a focus of interest with respect to novel therapies for cardiovascular disease. Members of this family bind differentially to three receptor tyrosine kinases, namely VEGF-R1, -R2 and -R3, and to the semaphorin receptors neuropilin 1 and 2. The role of VEGF-R1 and the factors that interact exclusively with this receptor (VEGF-B and placenta growth factor) has remained controversial. 2. To further elucidate the role of VEGF-B in blood vessel formation and function, we have expressed, purified and refolded both naturally occurring VEGF-B isoforms and a truncated amino acid 10-108 form. All refolded proteins have been demonstrated to bind to VEGF-R1 with appropriate kinetics in biosensor-based analysis. 3. Robust cell assays for VEGF-R1 ligands, such as VEGF-B, have been problematic. We have developed an assay based on a chimeric receptor consisting of extracellular domains 1-4 of VEGF-R1 and the transmembrane and intracellular domains of gp130. The cell line expresses luciferase to high levels 24 h after exposure to VEGF-A and both refolded VEGF-B167 and the short 10-108 isoform have been demonstrated to be active in this assay. 4. The novel cell-based assay, in combination with a variety of immunochemical approaches, has been used to identify and characterize monoclonal antibodies that neutralize VEGF-B activity.

Rapid secretion of interleukin-1beta by microvesicle shedding

The proinflammatory cytokine interleukin-1beta (IL-1beta) is a secreted protein that lacks a signal peptide and does not follow currently known pathways of secretion. Its efficient release from activated immune cells requires a secondary stimulus such as extracellular ATP acting on P2X(7) receptors. We show that human THP-1 monocytes shed microvesicles from their plasma membrane within 2-5 s of activation of P2X(7) receptors. Two minutes after such stimulation, the released microvesicles contained bioactive IL-1beta, which only later appeared in the vesicle-free supernatant. We conclude that microvesicle shedding is a major secretory pathway for rapid IL-1beta release from activated monocytes and may represent a more general mechanism for secretion of similar leaderless secretory proteins.

Cytologic and biochemical changes associated with inoculation of amniotic fluid and meconium into lungs of neonatal rats

OBJECTIVE

To evaluate the effect of homologous amniotic fluid and meconium inoculated intratracheally into the lungs of neonatal rats.

ANIMALS

153 male 7-day-old Fischer-344 rats.

PROCEDURE

Amniotic fluid was obtained by cesarean section from the uterus of pregnant rats and meconium was collected at the time of birth from the gastrointestinal tract of neonatal rats. Neonatal rats were randomly allocated into 5 treatment groups. Two groups received 0.05 ml of saline (0.9% NaCl) solution; the third and fourth groups received 0.05 ml of 50% or 100% amniotic fluid, respectively; the fifth group was inoculated with 0.05 ml of a 20% suspension of meconium. Six or 7 rat pups/group were euthanatized by exsanguination under halothane anesthesia at postinoculation days 1, 3, 7, and 14. The magnitude of injury and inflammatory response was determined by biochemical and cytologic analyses of bronchoalveolar lavage fluid.

RESULTS

Inoculation with saline solution and amniotic fluid did not induce pulmonary injury or inflammatory response. Inoculation with meconium induced significant (P < 0.01) injury and inflammatory response, characterized by the release of cytosolic enzymes and recruitment of neutrophils in the lung.

CONCLUSIONS

Saline solution is an innocuous vehicle that can be safely used in intratracheal inoculations in neonatal rats. Homologous amniotic fluid, despite containing keratin and epidermal cells, does not cause acute injury or inflammation in the lung. In contrast, meconium acts as a toxic substance injuring respiratory cells and causing a vigorous but transient leukocytic inflammatory reaction in the lungs.

NAIP protects the nigrostriatal dopamine pathway in an intrastriatal 6-OHDA rat model of Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder of the basal ganglia, associated with the inappropriate death of dopaminergic neurons of the substantia nigra pars compacta (SNc). Here, we show that adenovirally mediated expression of neuronal apoptosis inhibitor protein (NAIP) ameliorates the loss of nigrostriatal function following intrastriatal 6-OHDA administration by attenuating the death of dopamine neurons and dopaminergic fibres in the striatum. In addition, we also addressed the role of the cysteine protease caspase-3 activity in this adult 6-OHDA model, because a role for caspases has been implicated in the loss of dopamine neurons in PD, and because NAIP is also a reputed inhibitor of caspase-3. Although caspase-3-like proteolysis was induced in the SNc dopamine neurons of juvenile rats lesioned with 6-OHDA and in adult rats following axotomy of the medial forebrain bundle, caspase-3 is not induced in the dopamine neurons of adult 6-OHDA-lesioned animals. Taken together, these results suggest that therapeutic strategies based on NAIP may have potential value for the treatment of PD.

Characterization of murine monoclonal antibody to tumor necrosis factor (TNF-MAb) formulation for freeze-drying cycle development

PURPOSE

This study was designed to characterize the formulation of protein pharmaceuticals for freeze-drying cycle development. Thermal properties of a protein formulation in a freezing temperature range are important in the development of freezing and primary drying phases. Moisture sorption properties and the relationship between moisture and stability are the bases for the design of the secondary drying phase.

METHODS

We have characterized the formulation of TNF-MAb for the purpose of freeze-drying cycle development. The methods include: DTA with ER probes, freeze-drying microscopy, isothermal water adsorption, and moisture optimization.

RESULTS

The DTA/ER work demonstrated the tendency to "noneutectic" freezing for the TNF-MAb formulation at cooling rates of -1 to -3 degrees C/min. The probability of glycine crystallization during freezing was quite low. A special treatment, either a high subzero temperature holding or annealing could promote the maximum crystallization of glycine, which could dramatically increase the Tg' of the remaining solution. The freeze-drying microscopy further indicated that, after the product was annealed, the cake structure was fully maintained at a Tp below -25 degrees C during primary drying. The moisture optimization study demonstrated that a drier TNF-MAb product had better stability.

CONCLUSIONS

An annealing treatment should be implemented in the freezing phase in order for TNF-MAb to be dried at a higher product temperature during primary drying. A secondary drying phase at an elevated temperature was necessary in order to achieve optimum moisture content in the final product.

The human preprotachykinin-A gene promoter has been highly conserved and can drive human-like marker gene expression in the adult mouse CNS

Toward an understanding of the mechanisms controlling Preprotachykinin-A (PPTA) transcription, we introduced a 380-kb human yeast artificial chromosome containing the PPTA gene tagged with the beta-galactosidase gene into transgenic mice. This resulted in a pattern of LacZ expression in the central nervous system (CNS) remarkably similar to that reported for PPTA mRNA in the rat. However, the human gene drove expression in areas of the mouse CNS not associated with strong PPTA expression in rodents but which have been shown to express PPTA in the human. This study clearly demonstrates the high degree of conservation of the mechanisms involved in PPTA transcription that has occurred throughout 100 million of divergent human and rodent evolution. This study also defines the maximum linear extent of the human PPT-A promoter. We believe these findings constitute the removal of a significant obstacle in studying the transcriptional regulation of the human PPTA gene in vivo.

Molecular models to analyse preprotachykinin-A expression and function

Towards an understanding of the mechanisms controlling Preprotachykinin A (PPT) expression we have generated a variety of molecular models to determine the mechanisms regulating both the tissue-specific and stimulus-inducible expression of the PPT gene. The approaches used include transgenic and virus vector models complementing biochemical analysis of promoter interactions with transcription factors. We have identified and characterised a yeast artificial chromosome (YAC) containing the human PPT gene and generated transgenic mouse lines containing multiple copies of this chromosome on a normal mouse genetic background. This resulted in a pattern of expression in the nervous system remarkably similar to that reported for PPT mRNA in rodents. In addition, this transgenic model has been constructed in such a manner to allow for over expression of tachykinins based on the number of extra alleles in the transgenic mouse. These animals allow us to further examine the function of the tachykinins and acts as a useful complement to existing PPT ablated mice. In vitro we have introduced the proximal PPT promoter in reporter gene constructs into adult neurones in both DRG and the CNS by an adenoassociated virus (AAV) vector or by biolistic transfection respectively. Using the AAV vector we have demonstrated that the proximal promoter can mediate the effects of NGF in adult rat DRG. These models allow us to delineate transcriptional domains involved in the physiological and pathological expression of the PPT gene.

Use of injectable potassium chloride for euthanasia of American lobsters (Homarus americanus)

Potassium chloride (KCl: 330 mg/ml) was assessed as an euthanasia agent in American lobsters (Homarus americanus). Two groups of 10 lobsters (408.2 to 849.9 g) were maintained at 11.9 to 12.1 degrees C ('warm') and 1.5 to 2.5 degrees C ('cold') to evaluate the possible effect of ambient temperature on response to KCl. Death was defined as time of cardiac arrest, as viewed and measured by use of ultrasound. The KCl solution was injected (100 mg of KCl/100 g of body weight) at the base of the second walking leg to flood the hemolymph sinus containing the ventral nerve cord with potassium. Disruption of this 'central nervous system' was immediate, followed by cardiac arrest within 60 to 90 seconds. Group median ( +/- SD) baseline heart rate was 42 +/- 14 'warm' and 36 +/- 5 'cold' beats per minute. Time until cardiac arrest ranged from 35 to 90 (57 +/- 18) seconds in the 'warm' group and from 40 to 132 (53 +/- 34) seconds in the 'cold' group. There was no significant difference between group medians for either parameter. Histologic lesions were limited to mild to moderate acute degeneration, characterized by cell swelling, loss of contraction bands, and occasional mild cytoplasmic vacuolation of skeletal muscle at the injection site. Injectable KCl solution was an effective, reliable method for euthanasia of H. americanus.

Case management in the Community Psychiatric Nursing Service in Hong Kong: describing the process

PURPOSE

To explore the roles, functions, and work practices of case managers and their perceptions on the implementation of case management in the Community Psychiatric Nursing Services.

METHODS

A qualitative descriptive approach was used. Data were collected from daily reports, field observations, reflective diaries, and small group interviews.

FINDINGS

The study showed the work practices of case managers were more intensive compared to the conventional community psychiatric nursing practice, and there was more involvement of clients and their family in the treatment process. Case managers identified liaison, coordination, supportive and family counseling, and teaching practical living skills as their important roles.

CONCLUSIONS

This study provides valuable information in understanding the process of case management and contributed to the development of case management as a care delivery model in Hong Kong.

One year's clinical experience with unenhanced spiral computed tomography for the assessment of acute loin pain suggestive of renal colic

OBJECTIVE

To assess the use of unenhanced spiral computed tomography (CT) as the primary investigation of choice for suspected acute renal colic in clinical urological practice. Patients and Methods Between 1 August 1997 and 31 July 1998, all patients attending a hospital accident and emergency department with acute loin pain suggestive of renal colic underwent a physical examination, urine analysis, plain abdominal radiography (if clinically indicated) and unenhanced spiral CT. The effective radiation dose and financial cost of unenhanced spiral CT and standard three-film emergency intravenous urography (IVU) were calculated.

RESULTS

In all, 116 patients were assessed, 63 of whom had calculi and related secondary phenomena of obstruction identified on unenhanced spiral CT. There were two false-positive and one false-negative result. An alternative urinary tract diagnosis was made in four patients, including two with renal cell carcinoma and one ureteric transitional cell carcinoma. Causes other than in the urinary tract were diagnosed in three patients, i.e. two with ovarian cyst and one with sigmoid diverticulitis. The effective radiation dose of unenhanced spiral CT was 4.7 mSv and that for three-film IVU was 1.5 mSv. The costs of both IVU and unenhanced spiral CT were identical.

CONCLUSIONS

Unenhanced spiral CT allows a rapid, contrast-medium-free, anatomically accurate diagnosis of urinary tract calculi and in the present series had a sensitivity of 98% and a specificity of 97%. CT provided an alternative diagnosis in 6% of patients. These advantages must be weighed against the threefold greater radiation dose of unenhanced spiral CT than with three-film IVU, and in practice the requirement for a radiologist to interpret routine axial scans.

The neuronal apoptosis inhibitory protein (Naip) is expressed in macrophages and is modulated after phagocytosis and during intracellular infection with Legionella pneumophila

Legionella pneumophila is an intracellular pathogen that causes Legionnaires' disease in humans. Inbred mouse strains are uniformly resistant to L. pneumophila infection with the notable exception of A/J, where the chromosome 13 locus Lgn1 renders A/J macrophages permissive to L. pneumophila replication. The mouse Lgn1 region is syntenic with the spinal muscular atrophy (SMA) locus on human chromosome 5 and includes several copies of the neuronal apoptosis inhibitory protein (Naip) gene. We have analyzed a possible link among Lgn1, Naip, and macrophage function. RNA expression studies show that Naip (mostly copy 2) mRNA transcripts are expressed in macrophage-rich tissues, such as spleen, lung, and liver and are abundant in primary macrophages. Immunoblotting and immunoprecipitation analyses identify Naip protein expression in mouse macrophages and in macrophage cell lines RAW 264.7 and J774A. Interestingly, macrophages from permissive A/J mice express significantly less Naip protein than their nonpermissive C57BL/6J counterpart. Naip protein expression is increased after phagocytic events. Naip protein levels during infection with either virulent or avirulent strains of L. pneumophila increase during the first 6 h postinfection and remain elevated during the 48-h observation period. This enhanced expression is also observed in macrophages infected with Salmonella typhimurium. Likewise, an increase in Naip protein levels in macrophages is observed 24 h after phagocytosis of Latex beads. The cosegregation of Lgn1 and Naip together with the detected Naip protein expression in host macrophages as well as its modulation after phagocytic events and during intracellular infection make it an attractive candidate for the Lgn1 locus.

An evaluation of the implementation of case management in the community psychiatric nursing service

This paper reports the preliminary results of a study on the implementation of case management in the community psychiatric nursing service (CPNS). The purpose of the study is to compare the outcome of case management service with the conventional practice of CPNS in the care of chronic schizophrenic clients. The impact of case management service on clients' clinical status, functional level and satisfaction was measured. A matched, pre-post, case-control group design was used to compare case management and conventional care groups. A specific case management model based on the practice at Carondelet Saint Mary's Hospital and Health Centre in Tucson has been developed to care for the schizophrenic clients in the community. Subjects in the experimental group were cared for by CPNs using this case management model. Subjects in the control group were cared for by CPNs based on current practices in the CPNS. Pre- and post-measures were taken upon recruitment and at 5 months later. Findings showed that the experimental group had better outcome in terms of their mental status and functional level when compared with the control group. They were generally more satisfied with the service. When comparing case managers' role with that of conventional CPNs, case managers performed more in areas such as assessment, liaison, case discussion and life skills training. This study demonstrates that this particular model of case management can be effective in caring for clients with long-term mental health problems in Hong Kong.

A serotonin transporter gene intron 2 polymorphic region, correlated with affective disorders, has allele-dependent differential enhancer-like properties in the mouse embryo

Polymorphic regions consisting of a variable number of tandem repeats within intron 2 of the gene coding for the serotonin transporter protein 5-HTT have been associated with susceptibility to affective disorders. We have cloned two of these intronic polymorphisms, Stin2.10 and Stin2.12, into an expression vector containing a heterologous minimal promoter and the bacterial LacZ reporter gene. These constructs were then used to produce transgenic mice. In embryonic day 10.5 embryos, both Stin2.10 and Stin2.12 produced consistent beta-galactosidase expression in the embryonic midbrain, hindbrain, and spinal cord floor plate. However, we observed that the levels of beta-galactosidase expression produced by both the Stin2.10 and Stin2.12 within the rostral hindbrain differed significantly at embryonic day 10.5. Our data suggest that these polymorphic variable number of tandem repeats regions act as transcriptional regulators and have allele-dependent differential enhancer-like properties within an area of the hindbrain where the 5-HTT gene is known to be transcribed at this stage of development.

Molecular analysis of cystinosis: probable Irish origin of the most common French Canadian mutation

Infantile nephropathic cystinosis, an autosomal recessive disease characterized by a lysosomal accumulation of cystine, presents as failure to thrive, rickets and proximal renal tubular acidosis. The cystinosis gene, CTNS, which maps to chromosome 17p13, encodes a predicted 55 kDa protein with characteristics of a lysosomal membrane protein. We have conducted extensive linkage analysis in a French Canadian cystinosis cohort identifying a founding haplotype present in approximately half (21/40) of the chromosomes studied. Subsequent mutational analysis, in addition to identifying two novel mutations, has unexpectedly revealed a mutation which has been previously found in Irish (but not French) cystinotic families on these 21 French Canadian chromosomes. Haplotype analysis of two Irish families with this mutation supports the hypothesis that Celtic chromosomes represent an extensive portion of cystinosis chromosomes in French Canada. Our analysis underlines the genetic heterogeneity of the French Canadian population, reflecting a frequently unrecognized contribution from non-Gallic sources including the Irish.

Kinetics of cell lysis, dye uptake and permeability changes in cells expressing the rat P2X7 receptor

1. Extracellular ATP acting on P2X7 receptors opens a channel permeable to small cations, creates an access pathway for the entry of larger molecular weight dyes, and causes cell death. We used whole-cell recording and fluorescence microscopy to measure the time courses of ionic currents, uptake of the propidium dye YO-PRO-1, and membrane disruption, in human embryonic kidney (HEK293) cells expressing the rat P2X7 receptor. 2. The ATP analogue 2', 3'-O-(benzoyl-4-benzoyl)-ATP (30 microM) induced membrane blebbing within 30-40 s of sustained application; this was 5-10 times slower when extracellular sodium was replaced by larger cations. 3. Fluorescence of YO-PRO-1 was detectable within 3 s, and the uptake reached a steady rate within 10-20 s; YO-PRO-1 uptake was greatly enhanced by removing extracellular sodium. 4. Electrophysiological measurements of current reversal potentials with intracellular sodium and extracellular cations of different sizes showed that the ionic channel progressively t'2+LE0i%-i"dilated during 10-20 s to a diameter greater than 1 nm (10 A). With short agonist applications (3-5 s) the pore dilatation and YO-PRO-1 uptake were reversible and repeatable. 5. Polyethylene glycols having molecular weights >= 5000 blocked the increase in cation permeability, YO-PRO-1 uptake and membrane blebbing. 6. We conclude that maximum P2X7 receptor activation causes an exponential dilatation of the ion channel with a time constant of 25 s to a final diameter of 3-5 nm from an initial minimum pore diameter of 0.8 nm.

Long-term systemic administration of human recombinant interleukin-1beta induces a dose-dependent fall in circulating parathyroid hormone in rats

The synergism/antagonism between interleukin (IL)-1beta and parathyroid hormone (PTH) has been the subject of in vitro and in vivo work, but a possible direct action of the cytokine on PTH release has not been reported. We have investigated the effect of a continuous infusion of human recombinant IL-1beta (rIL-1beta) on circulating PTH during a 14-day period in 7-week-old female rats. This time interval was chosen in order to exclude initial hypercalcemia and to enable data collection under steady-state conditions. Five groups of 20 animals each had miniosmotic pumps (Alzet 2002, 200 microl) implanted subcutaneously and primed to release either distilled water (controls) or 100, 500, 1,000 and 2, 000 ng/24 h of rIL-1beta. Blood was drawn on days 1 and 14 for PTH, corticosterone and Ca2+ determinations. Adequate biological activity of the infused rIL-1beta was supported by elevated rectal temperature records and significant elevations of plasma corticosterone on day 14. The 100-ng dose had no effect but 500-2, 000 ng rIL-1beta/24 h significantly reduced plasma PTH in a dose-dependent manner down to 54% of basal value (20.4 +/- 1.1 vs. 15.3 +/- 1.4 pg/ml for 500 ng, p < 0.005; 20.5 +/- 1.3 vs 12.3 +/- 1.1 for 1,000 ng, p < 0.001, and 19.5 +/- 2.0 vs. 10.6 +/- 1.1 pg/ml for 2,000 ng, p < 0.0008). Despite these findings, no differences in blood Ca2+ could be detected between treated animals and controls. The following conclusions can be inferred from the foregoing: Systemic administration of rIL-1beta to rats induced a dose-dependent fall in circulating PTH without altering calcemia, calling into question the biological relevance of the former finding. Although the recorded PTH depression may indeed not have been severe enough to cause hypocalcemia, it can be hypothesized that osteoclast activation by rIL-1beta would enhance bone mineral release into the pool compensating for depressed PTH activity.

Effects of soluble interleukin-1 type II receptor on rabbit antigen-induced arthritis: clinical, biochemical and histological assessment

OBJECTIVES

To investigate the effects of soluble interleukin-1 (IL-1) type II receptor (sIL-1RII) on a number of clinical, biochemical and histological parameters in rabbit antigen-induced arthritis.

METHODS

Arthritis was induced by intra-articular injection of methylated bovine serum albumin (mBSA) into rabbits pre-sensitized to the same antigen. An initial i.v. bolus of sIL-1RII was administered, followed by s.c. mini-pump dosing for 14 days, starting at the time of the arthritis induction. Animals received vehicle (saline 500 microl + 5 microl/h), low-dose sIL-1RII (13.4 microg + 1.34 microg/h) or high-dose sIL-1RII (40.2 microg + 4.02 microg/h).

RESULTS

Marked, dose-related inhibition of joint diameter, plasma prostaglandin E2 (PGE2), and synovial fluid IL-1alpha and IL-1beta concentrations were seen after administration of sIL-1RII. However, synovial fluid PGE2 concentrations and synovial fluid cell counts were not affected. A significant inhibitory effect was also seen histologically on soft-tissue swelling and joint damage with high-dose sIL-1RII.

CONCLUSIONS

These results demonstrate that IL-1 plays an important role in the pathogenesis of rabbit antigen-induced arthritis, thus confirming it as an excellent animal model with respect to evaluating anti-cytokine therapies for rheumatoid arthritis.

Avian species differences in susceptibility to noise exposure

Previous studies of hair cell regeneration and hearing recovery in birds after acoustic overstimulation have involved relatively few species. Studies of the effects of acoustic overexposure typically report high variability. Though it is impossible to tell, the data so far also suggest there may be considerable species differences in the degree of damage and the time course and extent of recovery. To examine this issue, we exposed four species of birds (quail, budgerigars, canaries, and zebra finches) to identical conditions of acoustic overstimulation and systematically analyzed changes in hearing sensitivity, basilar papilla morphology, and hair cell number. Quail and budgerigars showed the greatest susceptibility to threshold shift and hair cell loss after overstimulation with either pure tone or bandpass noise, while identical types of overstimulation in canaries and zebra finches resulted in much less of a threshold shift and a smaller, more diffuse hair cell loss. All four species showed some recovery of threshold sensitivity and hair cell number over time. Canary and zebra finch hearing and hair cell number recovered to within normal limits while quail and budgerigars continued to have an approximately 20 dB threshold shift and incomplete recovery of hair cell number. In a final experiment, birds were exposed to identical wide-band noise overstimulation under conditions of artificial middle ear ventilation. Hair cell loss was substantially increased in both budgerigars and canaries suggesting that middle ear air pressure regulation and correlated changes in middle ear transfer function are one factor influencing susceptibility to acoustic overstimulation in small birds.

Pore dilation of neuronal P2X receptor channels

P2X receptors are ligand-gated ion channels activated by the binding of extracellular adenosine 5'-triphosphate (ATP). Brief (< 1 s) applications of ATP to nodose ganglion neurons or to cells transfected with P2X2 or P2X4 receptor cDNAs induce the opening of a channel selectively permeable to small cations within milliseconds. We now show that, during longer ATP application (10-60 s), the channel also becomes permeable to much larger cations such as N-methyl-D-glucamine and the propidium analog YO-PRO-1. This effect is enhanced in P2X2 receptors carrying point mutations in the second transmembrane segment. Progressive dilation of the ion-conducting pathway during prolonged activation reveals a mechanism by which ionotropic receptors may alter neuronal function.

Recovery by ascorbate of impaired nitric oxide-dependent relaxation resulting from oxidant stress in rat aorta

1. In this study we investigated the ability of ascorbate to protect nitric oxide from destruction by superoxide anion. 2. Ascorbate produced concentration-dependent relaxation of rings of rat aorta, comprising two components: the first, seen at 1-300 microM, reached a maximum of 45.3+/-2.8%, and was abolished by endothelial removal or treatment with L-NAME (100 microM), demonstrating involvement of nitric oxide. The second occurred at concentrations of 1 mM and above and was associated with falls in the pH of the bathing fluid. 3. Pretreatment with ascorbate at concentrations up to 3 mM had no effect on the relaxation to acetylcholine (10 nM-10 microM) on endothelium-containing rings or adenosine (0.1 microM-3 mM) on endothelium-denuded rings. 4. An oxidant stress was applied to aortic rings, comprising inhibition of endogenous Cu/Zn superoxide dismutase by diethyldithiocarbamate (0.1 mM) followed by generation of superoxide anion by hypoxanthine (0.1 mM/xanthine oxidase (16 u ml(-1)). This reduced maximal acetylcholine-induced relaxation from 96.7+/-1.3% to 42.4+/-3.5% (P<0.001). Treatment with ascorbate (30 microM-3 mM) reversed this blockade in a concentration-dependent manner. 5. Our findings show that ascorbate has the ability to protect nitric oxide from destruction by superoxide anion. This action is seen with ascorbate at levels normally present in plasma, suggesting that this antioxidant may exert a tonic protective effect on nitric oxide within the vasculature.

The processes of case management: a review of the evaluation of a pilot study for elderly people in Hong Kong

AIM

This paper is based on research into case management that aimed to evaluate the processes of the introduction of case management for elderly people into the community nursing services in Hong Kong.

BACKGROUND

The Hospital Authority in Hong Kong introduced a pilot Case Management scheme into the Community Nursing Services. A research project was therefore developed to evaluate this case management model.

METHOD

The processes were measured through information gained from group interviews, daily diaries and weekly activity sheets.

FINDINGS

The roles and work practices of the Care Coordinators and Case Managers are described and the benefits of case management to patients, carers and nurses are highlighted. Difficulties are also discussed and good practices are identified.

CONCLUSION

Staff in the hospital and community need time to get used to the model of case management and to the accompanying documentation. The role of the case manager needs to be clearly dilineated.

Increased mature interleukin-1beta (IL-1beta) secretion from THP-1 cells induced by nigericin is a result of activation of p45 IL-1beta-converting enzyme processing

Perregaux and Gabel (Perregaux, D., and Gabel, C. A. (1994) J. Biol. Chem. 269, 15195-15203) reported that potassium depletion of lipopolysaccharide-stimulated mouse macrophages induced by the potassium ionophore, nigericin, leads to the rapid release of mature interleukin-1beta (IL-1beta). We have now shown a similar phenomenon in lipopolysaccharide-stimulated human monocytic leukemia THP-1 cells. Rapid secretion of mature, 17-kDa IL-1beta occurred, in the presence of nigericin (4-16 microM). No effects on the release of tumor necrosis factor-alpha, IL-6, or proIL-1beta were seen. Addition of the irreversible interleukin-1beta-converting enzyme (ICE) inhibitor, Z-Val-Ala-Asp-dichlorobenzoate, or a radicicol analog, inhibited nigericin-induced mature IL-1beta release and activation of p45 ICE precursor. The radicicol analog itself did not inhibit ICE, but markedly, and very rapidly depleted intracellular levels of 31-kDa proIL-1beta. By contrast, dexamethasone, cycloheximide, and the Na+/H+ antiporter inhibitor, 5-(N-ethyl-N-isopropyl)amiloride, had no effect on nigericin-induced release of IL-1beta. We have therefore shown conclusively, for the first time, that nigericin-induced release of IL-1beta is dependent upon activation of p45 ICE processing. So far, the mechanism by which reduced intracellular potassium ion concentration triggers p45 ICE processing is not known, but further investigation in this area could lead to the discovery of novel molecular targets whereby control of IL-1beta production might be effected.

Cloning and characterization of the multiple murine homologues of NAIP (neuronal apoptosis inhibitory protein)

The spinal muscular atrophies (SMAs), characterized by degeneration of spinal cord motor neurons, are among the most common autosomal recessive disorders. We have previously reported the characterization of an SMA-associated gene designated NAIP (neuronal apoptosis inhibitory protein). This gene, which encodes a protein homologous to the baculoviral inhibitor of apoptosis proteins, is deleted in a significant proportion of individuals with type I SMA, is expressed in motor neurons, and inhibits apoptosis both in vitro and in vivo. Here we present the cloning and characterization of multiple copies of the mouse homologue of NAIP, Naip1-Naip6. Our analysis of the genomic organization of Naip indicated the existence of a minimum of six distinct Naip loci in the 129/SvJ mouse strain. However, Southern blot analysis revealed that only three of these loci contained the 5'UTR element essential for translation in the CNS. The coding region of one of these three potentially functional loci (Naip1) demonstrates 77% homology to NAIP at the nucleotide level and 68% identity at the amino acid level.

Loss of endothelium-derived nitric oxide in rabbit aorta by oxidant stress: restoration by superoxide dismutase mimetics

1. Structurally distinct superoxide dismutase (SOD) mimetics were examined for their ability to protect nitric oxide (NO) from destruction by oxidant stress in rabbit aorta. 2. These were the spin traps, PTIYO (4-phenyl-2,2,5,5-tetramethyl imidazolin-1-yloxy-5-oxide), tempol (4-hydroxy 2,2,6,6,-tetramethylpiperidine-1-oxyl) and tiron (4,5-dihydroxy-1,3-benzene-disulphonic acid), the metal salts, CuSO4 and MnCl2, and the metal-based agents CuDIPS (Cu (II)-[diisopropylsalicylate]2) and MnTMPyP (Mn (III) tetrakis [1-methyl-4-pyridyl]porphyrin). 3. Oxidant stress was generated in isolated aortic rings by inactivating endogenous Cu/Zn SOD with diethyldithiocarbamate (DETCA; 60 min) either alone at 3 mM or at 0.3 mM in combination with superoxide generation using xanthine oxidase (XO; 4.8 mu ml(-1)) and hypoxanthine (HX; 0.1 mM). 4. Acetylcholine (ACh)-induced relaxation was inhibited by DETCA (3 mM, 60 min) and was not restored by exogenous SOD (250 u ml(-1)), suggesting the oxidant stress was intracellular. MnTMPyP (600 microM and 1 mM) and MnCl2 (100 microM) were the only agents to reverse the blockade of ACh-induced relaxation. 5. Addition of XO/HX to DETCA (0.3 mM)-treated tissues powerfully impaired ACh-induced relaxation and exogenous SOD (250 u ml(-1)) fully reversed the blockade, suggesting the oxidant stress was extracellular. CuDIPS (0.1-3 microM), CuSO4 (0.3-3 microM), MnCl2 (1-100 microM) and MnTMPyP (100-600 microM) also reversed blockade powerfully, tempol (30 microM-1 mM) and tiron (0.3-10 mM) reversed blockade weakly and PTIYO (10-300 microM) enhanced the blockade. 6. Thus, MnTMPyP was the only SOD mimetic to restore NO-dependent relaxation in conditions of both extracellular and intracellular oxidant stress. This agent may, therefore, provide a lead in the development of SOD mimetics for the treatment of pathologies associated with oxidant stress.

Elevation of neuronal expression of NAIP reduces ischemic damage in the rat hippocampus

We show here that transient forebrain ischemia selectively elevates levels of neuronal apoptosis inhibitory protein (NAIP) in rat neurons that are resistant to the injurious effects of this treatment. This observation suggests that increasing NAIP levels may confer protection against ischemic cell death. Consistent with this proposal, we demonstrate that two other treatments that increase neuronal NAIP levels, systemic administration of the bacterial alkaloid K252a and intracerebral injection of an adenovirus vector capable of overexpressing NAIP in vivo, reduce ischemic damage in the rat hippocampus. Taken together, these findings suggest that NAIP may play a key role in conferring resistance to ischemic damage and that treatments that elevate neuronal levels of this antiapoptotic protein may have utility in the treatment of stroke.

Two enhancer domains control early aspects of the complex expression pattern of Msx1

To understand how the complex embryonic expression pattern of the Msx1 gene is produced a transgenic analysis of 13 kb of DNA around the Msx1 locus was carried out. Most of the extensive expression pattern of the Msx1 gene was reproduced in transgenics using the LacZ gene fused to 5 kb of Msx1 5' flanking DNA. Two enhancer domains were identified which produced this pattern. The distal element produced expression in the first arch and the nasal epithelium and was restricted to 240 bp. However, the proximal element which produced expression in superficial nasal epithelium, dorsal and ventral myotome, limb mesenchyme, eye, ear, roof plate, second arch, genital ridge and epiphysis, was contained in only 78 bp.

Myogenic contraction by modulation of voltage-dependent calcium currents in isolated rat cerebral arteries

1. Tissue blood flow and blood pressure are regulated by the spontaneous, myogenic, contraction developed by resistance arteries. However, the cellular mechanisms underlying myogenic contraction are not understood. In this study, the mechanisms of myogenic contraction in cerebral resistance arteries were investigated. 2. The vasoconstriction observed in response to increased pressure in cerebral resistance arteries (myogenic reactivity) was dependent on Ca2+ entry through voltage-dependent Ca2+ channels, since it was abolished by Ca2+ removal and by dihydropyridine antagonists of voltage-dependent Ca2+ channels. 3. Myogenic reactivity persisted in a high-K+ saline, with reduced Ca2+, where membrane potential is presumed to be clamped. Therefore, membrane depolarization alone does not fully account for the increased voltage-dependent Ca2+ channel opening. 4. Voltage-dependent Ca2+ currents in single smooth muscle cells isolated from the resistance artery were substantially increased by applying positive pressure to the patch electrode evoking membrane stretch. 5. Myogenic reactivity remained unaffected by ryanodine and therefore was independent of internal ryanodine-sensitive Ca2+ stores. 6. The myofilament Ca2+ sensitivity was not increased by elevated pressure in alpha-toxin-permeabilized arteries. However, pharmacological activation of protein kinase C or G proteins did increase the myofilament Ca2+ sensitivity. 7. Myogenic contraction over the pressure range 30-70 mmHg could be accounted for by an increase in [Ca2+]i from 100 to 200 nM. 8. It is concluded that modest increases in [Ca2+]i within the range 100-200 nM can account for that myogenic contraction, and that stretch-evoked modulation of Ca2+ currents may contribute to the myogenic response.