Absence of cocaine- and amphetamine-regulated transcript results in obesity in mice fed a high caloric diet

Cart (cocaine- and amphetamine-regulated transcript) was first identified to be a major brain mRNA up-regulated by cocaine and amphetamine. The CART protein has been established as a satiety factor closely associated with the action of leptin. To assess CART's role as an anorexigenic signal, we have generated CART-deficient mice by gene targeting. On a high fat diet, CART-deficient and female heterozygous mice, but not male heterozygous mice, showed statistically significant increases in weekly food consumption, body weight, and fat mass compared with their wild-type littermates. Furthermore, CART-deficient and female heterozygous mice were significantly heavier when fed a high fat diet than on a regular chow diet at 17 wk of age and at the 14th wk of the feeding studies. However, wild-type or male heterozygous mice showed no weight variations attributable to caloric contents of the diet at that age. Contrary to the obese phenotypes shown in MC4R-, proopiomelanocortin-, or leptin-deficient mice, our results showed that CART deficiency predisposed mice to become obese on a calorically dense diet. The results also show that CART may not be a major anorectic signal compared with proopiomelanocortin or leptin in the regulation of energy homeostasis.

Change management in primary care: design and evaluation of an internet-delivered course

OBJECTIVES

To deliver and evaluate an internet course in change management for primary care professionals.

DESIGN

A 12-week course delivered over the internet. Respondents were allocated into two groups: one had access to the course tutor individually, while the other could also communicate with the rest of the learner group. Learning outcomes were assessed by means of pre- and post-intervention questionnaires and by interviews with some participants.

SUBJECTS

111 primary care professionals.

RESULTS

Subjects showed significant improvements on all learning outcomes. The group with access to the course tutor alone completed more units and had greater improvements in their learning outcomes. More of this group completed the course and completed a portfolio. Respondents who could communicate with other members of the group did not find this a positive experience.

CONCLUSION

The internet can be used to deliver learning in change management to primary care professionals. Access to a discussion forum did not improve, and possibly impaired learning. More work is needed on the mentoring of internet learning.

Enhanced CD4+ T cell proliferation and Th2 cytokine production in DR6-deficient mice

We have found that DR6, a member of the TNF receptor family, is highly expressed in resting T cells and downregulated in activated T cells. DR6-targeted mutant mice were generated and showed normal development. However, DR6(-/-) CD4(+) T cells hyperproliferated in response to TCR-mediated stimulation and protein antigen challenge. Activated DR6(-/-) CD4(+) T cells exhibited upregulated CD25 expression and enhanced proliferation in response to exogenous IL-2 stimulation. In addition, increased CD28 and reduced CTLA-4 expression were observed in these cells. Enhanced Th2 cytokine production by activated DR6(-/-) CD4(+) T cells was associated with the increased transcription factor NF-ATc in nuclei. DR6, therefore, functions as a regulatory receptor for mediating CD4(+) T cell activation and maintaining proper immune responses.

Multi-Institutional Phase I/II Trial of Oral Bexarotene in Combination With Cisplatin and Vinorelbine in Previously Untreated Patients With Advanced Non–Small-Cell Lung Cancer

PURPOSE: Bexarotene (Targretin; Ligand Pharmaceuticals, Inc, San Diego, CA) is a retinoid-X-receptor (RXR)-selective retinoid with preclinical antitumor activity in squamous cell cancers. In this phase I/II trial, we combined bexarotene with cisplatin and vinorelbine in the treatment of patients with non–small-cell lung cancer (NSCLC).

PATIENTS AND METHODS: Forty-three patients who had stage IIIB NSCLC with pleural effusion or stage IV NSCLC and had received no prior therapy received bexarotene in combination with cisplatin (100 mg/m2) and vinorelbine (alternating doses of 30 mg/m2 and 15 mg/m2). In the phase I portion, the daily dose of bexarotene was escalated in cohorts of three patients from 150 mg/m2 to 600 mg/m2, beginning 1 week before the start of the cisplatin-vinorelbine regimen. Once the maximum-tolerated dose (MTD) of bexarotene was determined, the study entered the phase II portion. Response rate was the primary end point; median survival time and 1-year survival rate were secondary end points.

RESULTS: In the phase I portion, the daily MTD of bexarotene was determined to be 400 mg/m2. Eight of 43 patients exhibited major responses. Seven (25%) of the 28 patients in the phase II portion responded to treatment. The median survival time in the phase II portion was 14 months; nine (32%) of the 28 patients were still alive at a minimum follow-up of 2 years. One-year and projected 3-year survival rates were 61% and 30%, respectively. The most common grade 3 and 4 adverse events were hyperlipemia, leukopenia, nausea, vomiting, pneumonia, dyspnea, anemia, and asthenia. Grade 3 and 4 laboratory abnormalities with incidences greater than 5% were decreased hemoglobin levels and WBC, absolute neutrophil, and absolute lymphocyte counts and increased prothrombin time and creatinine and amylase levels. Of the two cases of pancreatitis, one required hospitalization and both were associated with increased triglyceride levels. There was one death secondary to renal insufficiency unrelated to bexarotene treatment.

CONCLUSION: In patients with advanced NSCLC, bexarotene with cisplatin and vinorelbine yielded acceptable phase II response rates (25%) and was associated with better-than-expected survival (14-month median survival time; 61% 1-year, 32% 2-year, and 30% projected 3-year survival rates). The regimen should be studied in larger clinical trials.

Long-term retrograde amnesia...the crucial role of the hippocampus

For patients with hippocampal pathology, disagreement exists in the literature over whether retrograde amnesia is temporally limited or very extensive depending on whether the anatomical damage is restricted to this structure or also involves additional temporal cortex. We report a comprehensive assessment of retrograde and anterograde memory functions of a severely global amnesic patient (VC). We found that he presented with a remarkably extensive and basically ungraded retrograde amnesia. This impairment profoundly affected four decades preceding the onset of his amnesia and encompassed both non personal and personal facts and events. VC also presented with a severe anterograde amnesia and a deficit in the acquisition of new semantic knowledge in the post-morbid period. Detailed MRI volumetric measurements revealed gross abnormalities in both hippocampi which were markedly shrunken. Of relevance to the debate on retrograde amnesia were the observations that the volumes of both entorhinal cortices and the remainder of both temporal lobes were normal. These data suggest that the hippocampus is critical not only for the efficient encoding and hence normal recall of new information but also for the recall of episodic information acquired before the onset of amnesia. Our results are compatible with the view that retrograde amnesia is both extensive and ungraded when the damage is limited to the hippocampus.

An inter-university community child health clinical placement programme for medical students

BACKGROUND

Inpatient teaching no longer reflects the full spectrum of paediatric practice and community-based programmes with clearly defined aims and evaluation of learning are becoming increasingly important. Competition for community resources poses threats to the delivery of effective community child health learning programmes by individual medical schools.

OBJECTIVES

To develop and evaluate a combined inter-university, child-focused, active learning programme in community child health.

METHODS

A total of 55 postgraduate-entry medical students from the Flinders University of South Australia and 97 undergraduate-entry University of Adelaide students were placed with 25 community child health agencies and instructed to assess services from a client perspective by tracking one child and family through multiple agency contacts. Following each placement, achievement of specific programme aims was evaluated by students and agency staff using a 7-point Likert scale.

RESULTS

Students and agency staff indicated substantial achievement of programme aims. Mean agency ratings were significantly higher than student ratings for three aims: students' experiencing a wider spectrum of health care problems than in teaching hospitals (5.7 +/- 1.5 versus 4.9 +/- 1.6, P < 0.001); the importance of social and environmental factors (5.9 +/- 1.0 versus 5.2 +/- 1.4, P < 0.001), and the importance of coordinating care (6.0 +/- 1.0 versus 5.2 +/- 1.2, P < 0.001). Ratings from undergraduate-entry students differed from those of postgraduate-entry students only with respect to the importance of social and environmental factors (4.8 +/- 1.4 versus 5.7 +/- 1.1, P < 0.001).

CONCLUSIONS

The new collaborative Community Child Health Programme substantially achieved learning aims and demonstrated effective integration of postgraduate- and undergraduate-entry medical students from two universities.

Use of the Internet by medical voluntary groups in the UK

Voluntary organisations and charities established as self-help groups are contributing to the democratisation of health-related information. As part of the Internet revolution in communication, such organisations are developing web sites. This short report surveyed all UK voluntary groups in the field of neurology. Of these, 71% had a web site, while the Internet was also used for research, advertising, fund raising and to host a discussion forum. These findings are discussed in terms of the quality of information available to people using the Internet.

Description of a simple test for CADASIL disease and determination of mutation frequencies in sporadic ischaemic stroke and dementia patients

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare inherited adult onset disease characterised most commonly by cerebral ischaemic events and dementia. It is caused by mutations in the Notch3 gene with most clustering in exons 3 and 4. Whether these mutations have any influence on common sporadic ischaemic stroke or dementia cases has not been investigated, partly hampered by the lack of a readily usable genetic test. An easy to use diagnostic array for CADASIL was designed using various restriction endonucleases for the known mutations in exons 3 and 4 and novel mismatch primers were designed where no such enzymes existed. This array was used to identify the allele frequencies of CADASIL mutations and polymorphisms in selected disease cohorts. Seventy patients with radiologically established sporadic ischaemic stroke and 77 patients from a specialist young dementia clinic were recruited. One hundred and seventeen age and sex matched asymptomatic controls were also identified. The diagnostic array was found to work well. None of the 14 known mutations and three previously identified polymorphisms (C474A, A587G, and C594A) in exons 3 and 4 were present in 140 stroke, 110 dementia, or 234 control chromosomes. Molecular variant C381T occurred with a higher frequency of 0.13, whereas G684A occurred with a lower frequency (0.09) than previously reported, although there were no statistical differences between selected cohorts. In conclusion, a readily usable genetic test for CADASIL has been devised that was used to determine allele frequencies in well characterised cohorts of sporadic stroke and dementia patients. The data suggest that despite the clinical resemblance, CADASIL is not a common masquerading cause of stroke or dementia. The test will enable units locally to rapidly screen patients with suspected CADASIL.

Interferon-alpha directly represses megakaryopoiesis by inhibiting thrombopoietin-induced signaling through induction of SOCS-1

Interferon (IFN)-alpha has proven useful for treating several clinical conditions, including chronic viral hepatitis and chronic myeloproliferative and lymphoproliferative disorders. In addition to its well-known antiviral effects, the cytokine exerts antiproliferative effects on many cell types, helping to explain its therapeutic usefulness in these latter conditions. However, this same property accounts for several undesirable effects, including thrombocytopenia, which can interfere with the successful clinical application of IFN-alpha. Unfortunately, the mechanisms responsible for the myelosuppressive effects of the cytokine are incompletely understood. The effects of IFN-alpha on megakaryocyte (MK) development were studied. Using several marrow cell purification techniques and quantitative culture methods, it was found that IFN-alpha directly inhibits thrombopoietin (TPO)-induced MK growth. Previous studies indicated that Janus kinase (JAK) and its substrates mediate the effects of TPO on cellular proliferation and survival. It was found that IFN-alpha directly suppresses TPO-induced phosphorylation of the JAK2 substrates c-Mpl and STAT 5 in a TPO-dependent hematopoietic cell line and of Mpl and STAT3 in primary murine MK. Moreover, IFN-alpha induces SOCS-1 production in these cells, which has been shown to inhibit TPO-induced cell growth. Because SOCS protein expression is induced by many cytokines and has been reported to extinguish signaling from several hematopoietic cytokine receptors, these results identify a molecular mechanism responsible for cytokine receptor cross-talk.

EEG correlates of the development of infant joint attention skills

The development of the capacity for social attention coordination, or "joint attention," is a major milestone of infancy. Data from a recent study of handicapped infants have raised the hypothesis that the tendency to initiate bids for joint attention may reflect processes associated with the frontal cortex to a greater extent than other forms of infant attention coordination (R. Caplan et al., 1993). This hypothesis was examined in a longitudinal study of 32 normally developing infants. The results indicated that EEG data at 14 months indicative of left frontal, as well as left and right central cortical activity, was associated with the tendency to initiate joint attention bids (IJA) at 14 and 18 months. In contrast, a pattern of left parietal activation and right parietal deactivation at 14 months was associated with the development of the capacity to respond to the joint attention bids (RJA) of others at 14 and 18 months. These results were interpreted to be consistent with a general anterior-posterior model of attention development (M. Posner & S. Petersen, 1990). The implications of these results for current conceptualizations of joint attention development, as well as for understanding the disturbance of joint attention skill development in autism are discussed.

A novel procedure for efficient genotyping of single nucleotide polymorphisms

Due to the surge in interest in using single nucleotide polymorphisms (SNPs) for genotyping a facile and affordable method for this is an absolute necessity. Here we introduce a procedure that combines an easily automatable single tube sample preparation with an efficient high throughput mass spectrometric analysis technique. Known point mutations or single nucleotide polymorphisms are easily analysed by this procedure. It starts with PCR amplification of a short stretch of genomic DNA, for example an exon of a gene containing a SNP. By shrimp alkaline phosphatase digest residual dNTPs are destroyed. Allele-specific products are generated using a special primer, a conditioned set of alpha-S-dNTPs and alpha-S-ddNTPs and a fresh DNA polymerase in a primer extension reaction. Unmodified DNA is removed by 5'-phospho-diesterase digestion and the modified products are alkylated to increase the detection sensitivity in the mass spectrometric analysis. All steps of the preparation are simple additions of solutions and incubations. The procedure operates at the lowest practical sample volumes and in contrast to other genotyping protocols with mass spectrometric detection requires no purification. This reduces the cost and makes it easy to implement. Here it is demonstrated in a version using positive ion detection on described mutations in exon 17 of the amyloid precursor protein gene and in a version using negative ion detection on three SNPs of the granulocyte-macrophage colony stimulating factor gene. Preparation and analysis of SNPs is shown separately and simultaneously, thus demonstrating the multiplexibility of this genotyping procedure. The preparation protocol for genotyping is adapted to the conditions used for the SNP discovery method by denaturing HPLC, thus demonstrating a facile link between protocols for SNP discovery and SNP genotyping. Results corresponded unanimously with the control sequencing. The procedure is useful for high throughput genotyping as it is required for gene identification and pharmacogenomics where large numbers of DNA samples have to be analysed. We have named this procedure the 'GOOD Assay' for SNP analysis.

Targeting adolescent mothers with depressive symptoms for early intervention

Infants of mothers with depressive symptoms show developmental delays if symptoms persist over the first 6 months of the infant's life, thus highlighting the importance of identifying those mothers for early intervention. In Study 1, mothers with depressive symptoms (n = 160) and mothers without depressive symptoms (n = 100) and their infants were monitored to identify variables from the first 3 months that predict which mothers would still be symptomatic at 6 months. A "dysregulation" profile was noted for the infants of depressed mothers, including lower Brazelton scores, more indeterminate sleep, and elevated norepinephrine, epinephrine, and dopamine levels at the neonatal period, and greater right frontal EEG activation, lower vagal tone, and negative interactions at the 3- and 6-month periods. A group of maternal variables from the neonatal and 3-month assessments accounted for 51% of the variance in the mothers' continuing depressive symptoms. These variables included greater right frontal EEG activation, lower vagal tone, and less positive interactions at 3 months, and elevated norepinephrine, serotonin, and cortisol levels at the neonatal stage. In Study 2, a similar sample of mothers with depressive symptoms (n = 160) and without depressive symptoms (n = 100) was recruited and followed to 3 months. Those symptomatic mothers who had values above (or below) the median (depending on the negative direction) on the predictor variables identified in Study 1 (taken from the first 3 months) were then randomly assigned to an intervention or a control group at 3 months. These groups were then compared with each other, as well as with the group without depressive symptoms, at 6 and 12 months. The intervention, conducted from 3 to 6 months, consisted of free day care for the infants and a rehab program (social, educational, and vocational) plus several mood induction interventions for the mothers, including relaxation therapy, music mood induction, massage therapy, and mother-infant interaction coaching. Although the mothers who received the intervention continued to have more depressive symptoms than did the nondepressed mothers, their interactions significantly improved and their biochemical values and vagal tone normalized. Their infants also showed more positive interations, better growth, fewer pediatric complications, and normalized biochemical values, and by 12 months their mental and motor scores were better than those of the infants in the control group.

Spatial working memory in Asperger's syndrome and in patients with focal frontal and temporal lobe lesions

Spatial working memory (SWM) was investigated in 15 patients with Asperger's syndrome (AS) comparing their performance to 18 age- and IQ-matched control subjects. An additional comparison was made with 20 unilateral frontal excision patients [9 right (RFL); 11 left (LFL)] and with 38 unilateral temporal lobectomy patients [18 right (RTL); 18 left (LTL)], the frontal and temporal lobe patients having separate matched control groups. SWM was tested using the Executive Golf Task, a test that also measures spatial strategy formation. The AS group showed a substantial deficit on SWM, but no impairment in strategy formation. The LFL showed the same pattern of impairment, but with a less substantial deficit. The RFL group showed a large deficit, but some of this was accounted for by a strategy formation impairment. Of the temporal lobe lesions groups, only the RTL group was impaired on SWM, but this group showed normal strategy formation. It was concluded that the SWM deficit in AS may reflect a more general difficulty in accessing different types of representations in order to guide voluntary behavior, providing at least a partial explanation for the executive deficits found in AS.

The Wisdom Project: virtual education in primary care

This article examines the development of the Wisdom Project, a pilot for the teaching of informatics to primary health care professionals, using an original educational model based on e-mail and Web pages. The article begins by placing the development of the Wisdom Project in the context of changes in medical education and training. The aims and objectives of Wisdom are outlined, and the methodologies for setting up and evaluating the project are described. The article then presents the results of the evaluation, including the identification of significant improvements in knowledge of CD ROMs (P = 0.01), e-mail (P = 0.03), Medline (P = 0.02), operating systems (P = 0.02), Web browsers (P = 0.003) and word processing (P = 0.03). Improvements in evidence-based practice (EBP) did not reach significance. Finally, a number of conclusions are presented, considering the lessons learnt for the future development of such projects.

Differences in amyloid deposition in islets of transgenic mice expressing human islet amyloid polypeptide versus human islets implanted into nude mice

Islet amyloid polypeptide (IAPP)-derived amyloid is frequently deposited in the islets of Langerhans in patients with chronic non-insulin-dependent diabetes mellitus (NIDDM). When human islets were implanted under the renal capsule in nude mice, amyloid occurred in 73% of the grafts within 2 weeks. In this study, we compare the deposition of amyloid in islets from a transgenic mouse strain expressing human IAPP (hIAPP) and in normal human islets after implantation in nude mice. The implantations were performed as follows: (1) nondiabetic recipients were given islets from transgenic mice alone, (2) human islets were implanted in the upper pole of the kidney and islets from transgenic mice were implanted in the lower pole of the kidney, (3) grafts containing a mixture of human and transgenic islets were implanted, and (4) transgenic islets and islets from nontransgenic littermates were implanted in therapeutic numbers into recipients made diabetic by a single injection of alloxan prior to implantation. The implants were removed after various periods from 4 days to 8 weeks. The implants were either fixed in Formalin, stained for amyloid, and viewed in polarized light, or processed for immunoelectron microscopy and studied after immunolabeling with specific antibodies against IAPP. We found that the course of amyloid deposition differed significantly between human islets and hIAPP-expressing mouse islets. In human islets, amyloid was mainly deposited intracellularly and only small amounts of amyloid were found extracellularly. In contrast, in islets from transgenic mice, amyloid was exclusively deposited extracellularly and deposition in this site was preceded by an aggregation of immunoreactive material along the basement membrane. These findings point to separate mechanisms for amyloid formation in these two models.

Pharmacology of LY315920/S-5920, [[3-(aminooxoacetyl)-2-ethyl-1- (phenylmethyl)-1H-indol-4-yl]oxy] acetate, a potent and selective secretory phospholipase A2 inhibitor: A new class of anti-inflammatory drugs, SPI

LY315920 is a potent, selective inhibitor of recombinant human, group IIA, nonpancreatic secretory PLA2 (sPLA2). In a chromogenic isolated enzyme assay, LY315920 inhibited sPLA2 activity with an IC50 of 9 +/- 1 nM or 7.3 x 10(-6) mole fraction, which approached the stiochiometric limit of this assay. The true potency of LY315920 was defined using a deoxycholate/phosphatidylcholine assay with a mole fraction of 1.5 x 10(-6). LY315920 was 40-fold less active against human, group IB, pancreatic sPLA2 and was inactive against cytosolic PLA2 and the constitutive and inducible forms of cyclooxygenase. Human sPLA2-induced release of thromboxane A2 (TXA2) from isolated guinea pig lung bronchoalveolar lavage cells was inhibited by LY315920 with an IC50 of 0.79 microM. The release of TXA2 from these cells by N-formyl-methionyl-leucyl-phenylalanine or arachidonic acid was not inhibited. The i.v. administration of LY315920, 5 min before harvesting the bronchoalveolar lavage cells, resulted in the inhibition of sPLA2-induced production of TXA2 with an ED50 of 16.1 mg/kg. Challenge of guinea pig lung pleural strips with sPLA2 produced contractile responses that were suppressed in a concentration-dependent manner by LY315920 with an apparent KB of 83 +/- 14 nM. Contractile responses induced by arachidonic acid were not altered. Intravenous or oral administration of LY315920 to transgenic mice expressing the human sPLA2 protein inhibited serum sPLA2 activity in a dose-related manner over a 4-h time course. LY315920 is a potent and selective sPLA2 inhibitor and represents a new class of anti-inflammatory agent designated SPI. This agent is currently undergoing clinical evaluation and should help to define the role of sPLA2 in various inflammatory disease states.

General practitioners and the Internet: modelling a 'virtual community'

BACKGROUND

Electronic discussion lists are used by many groups, including GPs, for communication and information sharing. The technology offers potential for formal learning and professional development. Various models have been proposed to describe the dynamics of such 'virtual' forums, and research is required to explore how such a discussion list might support professional development.

OBJECTIVE

We aimed to explore the use of the Internet-based discussion group gp-uk by GPs and their colleagues.

METHODS

We carried out a qualitative study of the electronic text generated by GPs and colleagues on an academic medical discussion group.

RESULTS

The list gp-uk has features of a collaborative medium, in which the audience are also contributors. There is support for a 'critical mass' model, in which a relatively small number of members contribute on a regular basis. There is little support for a 'discretionary database' model of more formal sharing of specific factual information.

CONCLUSIONS

The findings indicate a model for a 'virtual classroom' for computer-mediated learning and professional development. A critical mass of participants is a requisite, the list should be facilitated to guide discussions and supporting resources such as an Internet web-site should be provided.