Transgenic mice overexpressing both amyloid beta-protein and perlecan in pancreatic acinar cells

Heparan sulfate proteoglycans such as perlecan are thought to facilitate amyloid fibril formation. Tg3695 mice overexpress perlecan core protein in many tissues including the brain and pancreas. Tg13592 mice overexpress the signal plus 99-amino acid carboxyl terminal sequences (C99) of amyloid beta-protein precursor in multiple tissues and develop amyloid deposits in the pancreas. To investigate a role of perlecan in beta-amyloidosis, we established doubly transgenic mice by crossing the two lines of transgenic mice. The expression levels of the two transgenes remained unchanged in the brain and pancreas and the doubly transgenic mice did not develop amyloid deposits in the brain up to 19-months of age. Amyloid load detected by thioflavine S in the pancreas of the doubly transgenic mice was not significantly different from that in the transgenic littermates expressing only C99. Amyloid load in the pancreas increased during aging. We found a positive correlation between the Abeta-immunoreactive (non-fibrillar and fibrillar) and thioflavine S-positive (fibrillar) Abeta deposits in the single (C99) but not doubly transgenic mice. Our results suggest that perlecan does not independently influence amyloid formation in the pancreas of the transgenic mice and that there may be other factors that may modulate amyloid formation together with perlecan.

Utility of azapeptides as major histocompatibility complex class II protein ligands for T-cell activation

Major histocompatibility complex class II (MHC II) protein binding and antigen specific activation of CD4+ "helper" T cells are demonstrated with peptides composed of the antigenic hen egg ovalbumin 325-339 peptide (OVA) substituted with azaamino acids. AzaAla and azaGly substitutions were made at 10 sequential peptide positions (326Ala-335Asn) that lie in the binding groove. The peptide positions substituted with azaamino acids encompass almost the entire binding groove, including positions where the identity of the amino acid side chain is known to have the most significant effect on MHC binding and the least effect on T-cell recognition. In addition, the T-cell contact 333Glu was substituted with azaGlu to generate a partial agonist ligand for the 3DO-54.8 T-cell hybridoma. Binding to MHC II protein was assayed by measuring the kinetic stability of complexes formed between detergent-solubilized MHC II I-A(d) protein and fluorescein-labeled OVA peptides using a fluorescence-HPLC assay. T-cell activation was also evaluated for aza-substituted peptides with azaamino acid substitutions at the peptide positions known to interact with the MHC II protein. All aza-substituted peptides showed detectable MHC binding, and some were found to show T-cell activation potency equal to the native peptide. Several of these were also found to be weak or partial agonists. Our results demonstrate that azaamino acids substituted into an antigenic peptide cause a subtle, global effect on peptide conformation that can be used to design altered peptide ligands (APL) as T-cell partial agonists. These may have potential as T-cell epitopes for synthetic vaccines and therapeutic agents for autoimmune diseases.

Overproduction of perlecan core protein in cultured cells and transgenic mice

Heparan sulphate proteoglycan (HSPG) and amyloid P component are the only macromolecules consistently associated with all varieties of amyloid, irrespective of the type of amyloid protein, suggesting that HSPG may play a pathogenetic role in amyloid formation through a common mechanism. In the case of Alzheimer's disease (AD), HSPG, such as perlecan, co-accumulates with amyloid-beta protein (Abeta), a main constituent of amyloid plaques, and paired helical filaments (PHFs). Additionally, in vitro, HSPG accelerates both Abeta fibril and PHF formation and protects Abeta from degradation. Therefore, this study first established lines of P19 mouse embryonic carcinoma cells stably carrying an expression vector encoding the complete perlecan core protein (approximately 400 kD). In the cell lysates, overexpressed perlecan was identified as an approximately 400 kD protein without glycosaminoglycan side-chains, while in the media, secreted perlecan was mostly glycosylated, suggesting that the secretion and glycosylation of perlecan are coupled. Next, transgenic mice were produced using the same expression vector. Marked perlecan overexpression occurred in the cytoplasm of multiple tissues including the brain, heart, kidney, and pancreas, without a discernible increase of perlecan in extracellular matrices. The transgenic mice up to 18 months of age did not develop amyloid or AD-like pathology in the brain or elsewhere, based on histochemical and immunohistochemical analyses. Thus, overproduction of perlecan core protein is insufficient to lead to amyloidosis and AD-like pathology.

Ureteral obstruction in a transplant kidney caused by an ovarian tumor

Ureteral obstruction in the transplant recipient can provide a diagnostic challenge. We report a case of ureteral obstruction 5 years after cadaveric renal transplantation due to an ovarian tumor. Magnetic resonance imaging provided essential anatomic information that eventually led to the diagnosis. To our knowledge, this is the first reported case of ureteral obstruction in a transplant kidney caused by an ovarian tumor.

Generalized strategies in the minority game

We show analytically how the fluctuations (i.e., standard deviation sigma) in the minority game can decrease below the random coin-toss limit if the agents use more general, stochastic strategies. This suppression of sigma results from a cancellation between the actions of a crowd, in which agents act collectively and make the same decision, and those of an anticrowd, in which agents act collectively by making the opposite decision to the crowd.

Phylogenetic analyses of mode of larval development

Phylogenies based on morphological or molecular characters have been used to provide an evolutionary context for analysis of larval evolution. Studies of gastropods, bivalves, tunicates, sea stars, sea urchins, and polychaetes have revealed massive parallel evolution of similar larval forms. Some of these studies were designed to test, and have rejected, the species selection hypothesis for evolutionary trends in the frequency of derived larvae or life history traits. However, the lack of well supported models of larval character evolution leave some doubt about the quality of inferences of larval evolution from phylogenies of living taxa. Better models based on maximum likelihood methods and known prior probabilities of larval character state changes will improve our understanding of the history of larval evolution.

Accumulation of amyloid-beta protein in exocrine glands of transgenic mice overexpressing a carboxyl terminal portion of amyloid protein precursor

Amyloid-beta protein (Abeta) and its precursor (betaPP) play important roles in the pathogenesis of Alzheimer disease and inclusion-body myositis. In humans, Abeta deposits are found in brain, skeletal muscle, and skin. Therefore, we have investigated possible Abeta deposits in multiple tissues of two transgenic mouse lines overexpressing the signal plus Abeta-bearing 99-amino acid carboxyl terminal sequences of betaPP under the control of a cytomegalovirus enhancer/beta-actin promoter. One of the lines developed Abeta-immunoreactive intracellular deposits consistently in the pancreas and lacrimal gland, and occasionally in gastric, DeSteno's, and lingual glands. Although the Abeta deposits increased during ageing and degenerative changes of the tissues were observed, little or no extracellular Abeta deposits were observed up to the age of 25 months. These lines of transgenic mice are useful for studying the molecular mechanisms of development and clearance of intracellular Abeta deposits.

Case management model for a community-based multiple sclerosis clinic

This article describes the process from inception to successful operation of a case management model of a community-based multiple sclerosis clinic. The article includes information regarding the pathophysiology, diagnosis, and clinical manifestations of multiple sclerosis. The assessment, planning, and intervention stages of the process are explained, and a case study of one clinic patient is provided.

Epstein-Barr virus-dependent lymphoproliferative disease: critical role of IL-6

Epstein-Barr virus (EBV)-induced lymphoproliferative disease (lpd) is a B cell neoplasm that affects patients who are immunosuppressed in the context of organ transplantation or HIV infection. A model for the aggressive form of this entity was generated by xenotransplantation of SCID mice with human peripheral blood leukocytes from individuals with prior contact with EBV. This model, where large B cell lymphoma occurs, was used to test the hypothesis that IL-6 has a major role in EBV-induced B cell tumorigenesis. IL-6 is known to differentiate B cells into immunoglobulin-secreting plasma cells and induce EBV replication, and xenochimeric animals have detectable serum levels of human IL-6. Human IL-6 inhibition with a neutralizing monoclonal antibody decreased tumor incidence from 62 % to 27 %. In addition, anti-IL-6 treatment significantly improved xenotransplanted animal survival, with median survival at > 245 days when compared to that of controls at 132 days. In conclusion, IL-6 plays a critical role in the pathogenesis of EBV-induced human lpd, and IL-6 inhibition may represent a new and promising preventive or therapeutic approach against this malignancy.

A t(2;19)(p13;p13.2) in a giant invasive cardiac lipoma from a patient with multiple lipomatosis

Cardiac lipomas occur infrequently but account for a significant portion of rare cardiac tumors. Common cutaneous lipomas have previously been associated with rearrangements of chromosome band 12q15, which often disrupt the high-mobility-group protein gene HMGIC. In this report, we describe the cytogenetic analysis of an unusual giant cardiac lipoma that exhibited myocardial invasion in a patient with a history of multiple lipomatosis (cutaneous lipoma, lipomatous gynecomastia, lipomatous hypertrophy of the interatrial septum, and dyslipidemia). Cytogenetic studies of cells derived from the cardiac lipoma demonstrated no abnormalities of chromosome 12, but did reveal a t(2;19)(p13;p13.2). A liposarcoma-derived oncogene (p115-RhoGEF) previously mapped to chromosome 19 and the low-density lipoprotein receptor gene (LDLR) previously mapped to chromosome band 19p13 were evaluated to determine whether they were disrupted by this translocation. Fluorescence in situ hybridization analyses assigned p115-RhoGEF to chromosome 19 in bands q13.2-q13.3 and mapped the LDLR to chromosome arm 19p in segment 13.2, but centromeric to the t(2;19) breakpoint. Thus, these genes are unlikely to be involved in the t(2;19)(p13;p13.2). Further studies of the regions of chromosomes 2 and 19 perturbed by the translocation in this unusual infiltrating cardiac lipoma will identify gene(s) that participate in adipocyte growth and differentiation and may provide insight into syndromes of multiple lipomatosis.

Defects in the regulation of beta-catenin in colorectal cancer

The molecular events that contribute to the progression of colon cancer are beginning to unravel. An initiating and probably obligatory event is the oncogenic activation of beta-catenin. This can come about by the loss of its negative regulator the adenomatous polyposis coli (APC) protein, or by mutations in the beta-catenin gene that result in a more stable protein product. The interaction between APC and beta-catenin, and additional proteins that affect assembly and signaling along this pathway, are discussed.

Utilization and outcome in an overnight psychiatric observation program at a Veterans Affairs Medical Center

OBJECTIVE

The effectiveness of an overnight psychiatric observation program was evaluated. The program was designed to avoid unnecessary hospitalization of patients experiencing acute psychiatric crises.

METHODS

Of 110 patients admitted to the observation unit at a Veterans Affairs medical center over a six-month period in 1996, the charts of 92 patients were retrospectively reviewed. Characteristics of patients referred to the program were documented, inpatient hospitalization rates and suicide rates in the six-month periods before and after admission to the observation unit were examined, and variables related to the need for hospitalization immediately after observation were explored.

RESULTS

Most of the 92 patients (98 percent) were referred from the medical center's emergency room. At the time of observation, 80 percent of the patients were unemployed, 55 percent expressed suicidal or homicidal ideation, 49 percent were intoxicated or at risk for alcohol withdrawal, and 41 percent were homeless. The most frequent psychiatric diagnosis was substance abuse or dependence (77 percent). The large majority of patients (88 percent) were referred the next day to other outpatient programs for follow-up and treatment, which avoided costly inpatient treatment. In the six months before admission to the observation program, the mean number of inpatient psychiatric bed days was 9.8, compared with 2.7 days in the six-month period after discharge from the observation program. No increase in suicide gestures or attempts was noted among the patients. No variables significantly predicted admission to inpatient care after the observation period.

CONCLUSIONS

Overnight observation programs may provide a cost-effective alternative to traditional inpatient treatment for some individuals with psychiatric disorders.

A tyrosine-phosphorylated protein that binds to an important regulatory region on the cool family of p21-activated kinase-binding proteins

The p21-activated kinases (Pak) are major targets of the small GTPases Cdc42 and Rac. We, and others, recently identified a family of proteins termed Cool/Pix, which interact with Pak3. In cells, p50(Cool-1) suppresses Pak activation by upstream activators; p85(Cool-1) has a permissive effect on Pak activation, and we now show that the closely related Cool-2 stimulates Pak kinase activity. To understand the differential regulation of Pak by Cool proteins, we screened for Cool-interacting proteins by affinity purification and microsequencing. This has led to the identification of two closely related proteins called Cat (Cool-associated, tyrosine phosphorylated), which contain a zinc finger followed by three ankyrin repeats. Cat-1 is identical to the recently identified binding partner for the beta-adrenergic receptor kinase (betaARK or GRK-2), which was shown to have Arf-GAP activity. Cat-1 and Cat-2 both bind to the COOH-terminal region of p85(Cool-1) and p85(Cool-2) but do not bind to p50(Cool-1). Cat-1 is tyrosine-phosphorylated in growing NIH 3T3 fibroblasts, and its tyrosine phosphorylation is increased following cell spreading on fibronectin, decreased in cells arrested in mitosis, and increased in the ensuing G(1) phase. Cat proteins are tyrosine-phosphorylated when co-expressed in cells with the focal adhesion kinase Fak and Src. These findings suggest that in addition to playing a role in Cool/Pak interactions, Cat proteins may serve as points of convergence between G protein-coupled receptors, integrins, Arf GTPases, cell cycle regulators, and Cdc42/Rac/Pak signaling pathways.

The F-box protein beta-TrCP associates with phosphorylated beta-catenin and regulates its activity in the cell

Defects in beta-catenin regulation contribute to the neoplastic transformation of mammalian cells. Dysregulation of beta-catenin can result from missense mutations that affect critical sites of phosphorylation by glycogen synthase kinase 3beta (GSK3beta). Given that phosphorylation can regulate targeted degradation of beta-catenin by the proteasome, beta-catenin might interact with an E3 ubiquitin ligase complex containing an F-box protein, as is the case for certain cell cycle regulators. Accordingly, disruption of the Drosophila F-box protein Slimb upregulates the beta-catenin homolog Armadillo. We reasoned that the human homologs of Slimb - beta-TrCP and its isoform beta-TrCP2 (KIAA0696) - might interact with beta-catenin. We found that the binding of beta-TrCP to beta-catenin was direct and dependent upon the WD40 repeat sequences in beta-TrCP and on phosphorylation of the GSK3beta sites in beta-catenin. Endogenous beta-catenin and beta-TrCP could be coimmunoprecipitated from mammalian cells. Overexpression of wild-type beta-TrCP in mammalian cells promoted the downregulation of beta-catenin, whereas overexpression of a dominant-negative deletion mutant upregulated beta-catenin protein levels and activated signaling dependent on the transcription factor Tcf. In contrast, beta-TrCP2 did not associate with beta-catenin. We conclude that beta-TrCP is a component of an E3 ubiquitin ligase that is responsible for the targeted degradation of phosphorylated beta-catenin.

Patients with systemic lupus erythematosus with high plasma levels of sFas risk relapse

OBJECTIVE

We related soluble Fas (sFas) levels to the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) in a longitudinal series of plasma samples of patients with SLE to evaluate the relation between excessive production of sFas and disease activity.

METHODS

We generated 21 monoclonal antibodies against Fas. Two of these were used to develop and validate a sensitive sandwich ELISA for the longitudinal analysis of sFas levels in plasma of 30 patients and 25 controls.

RESULTS

At the start of followup, a significant elevation (p<0.0001) was found in sFas levels in SLE (1167+/-347 pg/ml sFas) compared to controls (618+/-98 pg/ml sFas). Also, at the start of the followup a significant difference (p = 0.0028) existed between patients who were going to have a relapse (1236+/-402 pg/ml sFas) during followup and patients who were not (809+/-276 pg/ml sFas). While sFas did not fluctuate with disease activity in individual patients, we found a strong correlation (r = 0.75, p<0.0001) between sFas and SLEDAI, but only at the time of relapse, when we analyzed the patients as a group.

CONCLUSION

In individual patients with SLE, sFas does not fluctuate with disease activity. However, patients with high plasma levels of sFas are at risk of relapse.

Normal haematological and serum biochemical values of Eurasian otters (Lutra lutra) from a Scottish rehabilitation centre

Blood samples were taken from 47 clinically normal, wild-born Eurasian otters (Lutra lutra) before they were released from a rehabilitation centre in Scotland between August 1990 and March 1996. Serum biochemistry profiles were determined for 47 animals and haematological profiles for 41, and the results from males, females, and animals under or over one year of age were analysed as separate groups and as pooled populations. The normal ranges for a wide variety of haematological and serum biochemical parameters of the Eurasian otter are presented, and significant differences with age and sex are detailed.

Amyloid-beta deposition in skeletal muscle of transgenic mice: possible model of inclusion body myopathy

Inclusion body myopathy is a progressive muscle disorder characterized by nuclear and cytoplasmic inclusions and vacuolation of muscle fibers. Affected muscle fibers contain deposits of congophilic amyloid, amyloid-beta immunoreactive filaments, and paired helical filaments, all of which are pathological hallmarks of Alzheimer's disease in brain. Accumulations of amyloid-beta and its precursor are thought to play important roles in the pathogenesis of both inclusion body myopathy and Alzheimer's disease. Overexpression of mutant forms of beta protein precursor in transgenic mice by neuron-specific promoters has been reported to cause amyloid deposits in the brain. Here we report that overexpression in transgenic mice of the signal plus 99-amino acid carboxyl-terminal sequences of beta protein precursor, under the control of a cytomegalovirus enhancer/beta-actin promoter, resulted in vacuolation and increasing accumulation of the 4-kd amyloid-beta and the carboxyl-terminus in skeletal muscle fibers during aging. These deposits in transgenic muscle only rarely showed Congo red birefringence. Thus, overexpression of part of beta protein precursor in transgenic mice led to development of some of the characteristic features of inclusion body myopathy. These mice may be a useful model of inclusion body myopathy, which shares a number of pathological markers with Alzheimer's disease.

Plasma thyroid hormones in premature infants: effect of gestational age and antenatal thyrotropin-releasing hormone treatment. TRH Collaborative Trial Participants

Thyroid hormones are important for both perinatal adaptation and long-term psychomotor development; however, there is limited information on the effects of extreme prematurity and antenatal TSH-releasing hormone (TRH) treatment on pituitary-thyroid function. In this study we assayed plasma triiodothyronine (T3) and TSH in infants who were part of a collaborative trial of antenatal maternal TRH therapy. Within the control population (n = 166), infants of 24-28-wk and 28-32-wk gestational age had comparable levels of T3 (0.94 and 1.06 nmol/L, respectively) and TSH (5.7 and 7.2 mU/L) at birth, but the increases at 2 h and subsequent T3 levels were less in the 24-28 wk versus 28-32-wk gestation infants. In the TRH-treated group (n = 131), T3 was lower in the first day for infants delivered 7-72 h after antenatal TRH compared with control infants. TSH at birth was approximately 3.5-fold greater for infants delivered at 0-6 h after the last TRH dose compared with the control group and was suppressed in infants delivering at 7-36 h. T3 and TSH levels were not different between control and TRH-treated groups at 3-28 d of age. In TRH stimulation tests on d 28, control and TRH-treated groups had similar peak levels of TSH and incidence of exaggerated response (TSH > or = 35 mU/L). We conclude that extremely premature infants have a reduced postnatal surge in TSH and T3 and maintain lower T3 concentrations, probably reflecting tertiary hypothyroidism. The stimulatory and suppressive effects of antenatal TRH treatment observed at birth are transient and do not affect pituitary-thyroid responsiveness at 28 d of age.

Expansion and division of conjoined twins

Omphalopagus conjoined twins were born by cesarean section after their 24-year-old gravida 2, para 1 mother went into labor at 35 weeks' gestation. Initial studies included roentenograms, an upper gastrointestinal study, small bowel follow-through, and computerized tomography with intravenous contrast from neck through pelvis. Results of these studies showed that the twins had very little shared vasculature, but did share a pericardium and liver parenchyma. The infants were allowed to gain weight and grow. After 3 weeks, tissue expanders were placed subcutaneously and were rapidly expanded in 2 weeks. The infants were then separated. An Argon Beam Coagulator was used to aid the separation of the liver. The abdominal fascia was closed primarily on each infant, and the skin easily closed without tension. During the first 36 hours of the postoperative course, both infants required significant ventilatory support including inhaled nitric oxide. After this period, the ventilatory support decreased dramatically and rapidly. The infants were discharged 9 days after their surgical separation. Conjoined omphalopagus twins, the use of tissue expanders and the Argon Beam Coagulator, and the postoperative course are discussed.

Fast surface profiling by spectral analysis of white-light interferograms with fourier transform spectroscopy

We present a fast white-light interference method for measuring surface depth profiles at nanometer scales. Previously reported white-light profilers have relied either on path difference scanning or on spectral analysis of the reflection from a fixed interferometer. We show that by performing this spectral analysis with an imaging Fourier transform spectrometer, the high speed of spectral techniques may be combined with the simple data interpretation characteristic of the scanning method. Giving experimental results from a profiler based on this principle, we show that real-time visualization of surface profiles is possible and we report measurements with a repeatability of approximately 5 nm rms. We also demonstrate good agreement with stylus profiler measurements.

Alzheimer's disease and heparan sulfate proteoglycan

Alzheimer's disease (AD) is a debilitating neurodegenerative disorder. Cardinal histopathologic changes of AD are neurofibrillary tangles (NFTs) and deposits of beta-amyloid protein (A-beta) in the form of neuritic plaques (NPs). Several different mutations found in patients with familial AD have been demonstrated to increase A-beta production, resulting in a common pathological cascade of beta-amyloidosis in the brain. Heparan sulfate proteoglycan (HSPG) has been co-localized with both A-beta in the NPs and NFTs. The proteoglycans are a family of complex macromolecules consisting of a protein core to which glycosaminoglycan (GAG) chains are covalently attached. HSPG has been shown to bind to A-beta, accelerate its fibril formation, and maintain its fibril stability. In AD and other neurodegenerative disorders, tau becomes hyperphosphorylated hence it is unable to bind to microtubules which results in the production of paired helical filaments, a building unit of NFTs. It has been shown in vitro that sulfated GAGs induce the formation of paired helical-like filaments under physiological conditions from tau. Furthermore, an interaction between HSPG and apolipoprotein E (a potent risk factor of AD) has been shown to be involved in neurodegeneration. Thus, substantial evidence exists to underscore important roles of HSPG in the etiology of AD.

Total enteral nutrition versus total parenteral nutrition during pediatric extracorporeal membrane oxygenation

OBJECTIVE

To evaluate the adequacy, tolerance, and complications of enteral nutrition, compared with parenteral nutrition, in pediatric patients requiring extracorporeal membrane oxygenation (ECMO).

DESIGN

A retrospective chart review of all patients placed on extracorporeal life support from January 1991 through December 1995.

SETTING

Medical/surgical pediatric intensive care unit at Egleston Children's Hospital, a tertiary care pediatric center.

PATIENTS

Twenty-nine consecutive pediatric patients who required ECMO and were provided nutritional support, either enterally or parenterally. Group A consisted of 14 patients who were provided nutritional support using total parenteral nutrition. Group B consisted of 15 patients. Two patients were excluded from group B because their ECMO run was <36 hrs, leaving insufficient data for analysis. The remaining 13 patients were provided total enteral nutrition during ECMO.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Both groups were similar in age, weight, pre-ECMO oxygenation index, alveolar-arterial oxygen difference, type, and duration of ECMO (p = NS). Comparison of percent ideal body weight on admission did not show a statistical difference between groups A and B (p = .883). There was no difference between the two groups in the time needed to achieve caloric goal (p = .536) from the initiation of ECMO. No complications were associated with the utilization of enteral feedings. Savings for the nutritional supplement was estimated to be $170 per day for the enterally fed group. The percentage of patients surviving was higher in the enterally fed patients compared with the parenterally fed group (79% vs. 100%), although this difference was not statistically significant (p = .47).

CONCLUSIONS

Enteral nutrition in patients receiving either venoarterial or venovenous ECMO is well tolerated, provides adequate nutrition, is cost effective, and is without complications, as compared with parenteral nutrition. These data suggest that total enteral nutrition can be safely administered for nutritional support in pediatric patients undergoing either venoarterial or venovenous ECMO.

Mechanisms of insulin resistance in experimental hyperinsulinemic dogs

This study was undertaken to characterize the insulin resistance and the mechanism thereof caused by chronic hyperinsulinemia produced in dogs by surgically diverting the veins of the pancreas from the portal vein to the vena cava. Pancreatic venous diversion (PVD, n = 8) caused a sustained increase in arterial insulin and decrease in portal insulin concentration compared with the control group (n = 6). Hyperinsulinemic euglycemic clamps were conducted 4 wk after surgery. The increase in the glucose disposal rate (GDR) was significantly less in the PVD group (39.0+/-5.0 vs. 27.9+/-3.2 micromol/kg/min, P < 0.01) compared with the control group, but the suppression of hepatic glucose production by insulin was similar for both groups. Muscle insulin receptor tyrosine kinase activity (IR-TKA) increased from 6.2+/-0.4 to 20.3+/-2.7 in the control group, but from 5.8+/-0.5 to only 12.7+/-1.7 fmol P/fmol IR in the PVD group (P < 0.01). With respect to the periphery, the time to half-maximum response (t1/2a) for arterial insulin was the same for both groups, whereas the t1/2a for lymph insulin (30+/-3 vs. 40+/-4 min, P < 0.05) and GDR (29+/-3 vs. 66+/-10 min, P < 0.01) were greater for the PVD group. Chronic hyperinsulinemia led to marked peripheral insulin resistance characterized by decreased insulin-stimulated GDR, and impaired activation of GDR kinetics due, in part, to reduced IR-TKA. Transendothelial insulin transport was impeded and was responsible for one third of the kinetic defect in insulin-resistant animals, while slower intracellular mechanisms of GDR were responsible for the remaining two thirds.

The nomadic engram: overtraining eliminates the impairment of discriminative avoidance behavior produced by limbic thalamic lesions

Combined lesions of the medial dorsal and anterior thalamic nuclei severely impair the acquisition of discriminative avoidance behavior, wherein rabbits learn to prevent foot-shock by stepping after a tone conditional stimulus (CS+), and they learn to ignore a different tone (CS-) that does not signal foot-shock. Neurons in these thalamic nuclei exhibit training-induced firing pattern changes during behavioral acquisition to asymptotic performance levels. However, the changes decline in magnitude during the course of post-asymptotic training (overtraining), suggesting a declining participation of the thalamic neurons in task mediation. In order to test this hypothesis, electrolytic or sham limbic thalamic lesions were induced either immediately after asymptotic performance was reached, or after the administration of training to asymptote and ten additional overtraining sessions. Retention after the lesions was assessed using an extinction procedure (CS presentation without foot-shock) followed by re-acquisition. Rabbits given lesions after criterion attainment exhibited a significant retention deficit during both the extinction and re-acquisition tests. However, no significant retention deficit was found in rabbits given 10 days of overtraining prior to the lesions. These results support the prediction derived from the neuronal data, of a time-limited involvement of limbic thalamic neurons in mediation of discriminative avoidance behavior.

Monitoring quality in the British health service--a case study and a theoretical critique

Details the results of a monitoring exercise introduced in one local hospital to address the amount of time that patients spent waiting when attending outpatient departments in hospitals. Discusses whether a purely quantitative approach to quality can deliver the desired improvements. Argues that quality measures should incorporate more qualitative dimensions, including the tapping of patient perceptions of their experiences, before a claim can be made that reducing waiting times has improved overall quality. Also argues that the frequent use of the term customer in the quality literature receives critical attention when it is applied in the NHS. The fact that the term conflates the roles of consumer and purchaser makes analysis potentially difficult. Suggests that regarding patients as customers (in the manner of some traditional approaches to quality) is not a useful aid to analysis.

Incorporating outpatient perceptions into definitions of quality

This paper reviews the ways in which quality measures have been defined by reference to objective measures and applied by the producers of health care to patients. Patient satisfaction surveys may be thought to redress this imbalance and will be addressed as a precursor to the discussion of the SERVQUAL methodology, developed to measure the gap between expectations and performance in service industries. An argument will be advanced that quality measurement is still producer-led and should incorporate the views of patients more directly into the quality measurement process. It is suggested that calibration or baseline surveys of patients be conducted which then identify the issues that may be subject to more sustained quantitative analysis. Quality monitoring should be conducted in such a way that particular sub-groups can be subject to routine analysis. Models of quality measurement need to incorporate the perspectives of many 'key players' in which the views of patients are complemented by relevant professional, clinical and managerial groups. The extent to which there is a disjunction between quality as objectively measured (e.g. by waiting times) and as experienced by patients will receive attention. Suggestions will be made that monitoring and clinic operations need to be more mutually reinforcing.

Activation of phospholipase D and phosphatidylinositol 4-phosphate 5-kinase in HL60 membranes is mediated by endogenous Arf but not Rho

Membrane-associated phospholipase D (PLD) in HL60 cells can be activated by the small GTP-binding proteins Arf and RhoA, but polyphosphorylated inositol lipids were required for maximum activity. The intact lipid was required because neither inositol 1,4, 5-trisphosphate nor stearoyl-arachidonyl glycerol could substitute for phosphatidylinositol 4,5-bisphosphate (PIP2). Arf-stimulated but not Rho-stimulated PLD activity was increased by the inclusion of Mg2+ and ATP. ATP-dependent PLD activation occurred when phosphatidylinositol 4-phosphate (PIP), PIP2, or phosphatidylinositol 3,4,5-trisphosphate (PIP3) were included, but PIP2 formation was only detected with PIP; no PIP3 production was detected under any conditions. Therefore, the ATP-dependent increase in PLD activity cannot be explained by PIP2 or PIP3 formation. Association of endogenous Arf and RhoA with membranes was increased by incubation with GTPgammaS. This treatment increased membrane PLD and PIP kinase activities in the absence of exogenous p21 proteins. Reduction of Arf translocation suppressed the increase in PLD and PIP kinase activities, whereas complete removal of Rho but not Arf from membranes with RhoGDI was without effect on PLD activity but increased PIP kinase activity. Therefore, although recombinant Arf and Rho can activate PLD and PIP kinase in HL60 cells, it is the endogenous Arf but not Rho that regulates PLD, and thus a role for Rho in the physiological regulation of PLD in HL60 cells is unlikely.

Release of leukemia inhibitory factor in primate sepsis. Analysis of the role of TNF-alpha

Leukemia inhibitory factor (LIF), a pleiotropic cytokine with many biologic effects overlapping with those of IL-6, has been implicated in the pathogenesis of sepsis. We here analyzed the kinetics of LIF in 13 baboons challenged with a lethal (n=6) or sublethal (n=7) dose of Escherichia coli. In addition, to assess the role of TNF-alpha in the induction of LIF in vivo, seven baboons were studied that had either received a bolus injection of recombinant human TNF-alpha (100 micrograms/kg, n=3), or to whom 15 mg/kg of an anti-TNF mAB before lethal E. coli challenge was administered (n=4). LIF levels increased 2 h after E coli challenge, and reached maximum values at 4 and 8 h after a sublethal (4.4 +/- 1.6 ng/ml) or lethal (40.9 +/- 3.8 ng/ml) dose, respectively. TNF-alpha injection induced a modest rise in LIF concentrations, peaking after 6 h (228 +/- 46 pg/ml). Circulating LIF correlated with plasma levels of IL-6, both after E. coli challenge (Spearman Rank coefficient of correlation (r) = 0.849, p&lt;0.001), as well as upon TNF-alpha injection (r=0.863, p&lt;0.001). Moreover, the E. coli-induced release of either cytokine was reduced 6- to 10-fold after pretreatment with anti-TNF mAb, except in one nonsurviving animal, which exhibited a progressive increase of LIF and IL-6 levels despite the absence of TNF immunoreactivity. These results show that TNF-alpha is an intermediate factor in concerted release of LIF and IL-6 in vivo, and indicate that the enhanced elaboration of these cytokines may predict disease outcome in severe sepsis.

Release of leukemia inhibitory factor in primate sepsis. Analysis of the role of TNF-alpha

Leukemia inhibitory factor (LIF), a pleiotropic cytokine with many biologic effects overlapping with those of IL-6, has been implicated in the pathogenesis of sepsis. We here analyzed the kinetics of LIF in 13 baboons challenged with a lethal (n=6) or sublethal (n=7) dose of Escherichia coli. In addition, to assess the role of TNF-alpha in the induction of LIF in vivo, seven baboons were studied that had either received a bolus injection of recombinant human TNF-alpha (100 micrograms/kg, n=3), or to whom 15 mg/kg of an anti-TNF mAB before lethal E. coli challenge was administered (n=4). LIF levels increased 2 h after E coli challenge, and reached maximum values at 4 and 8 h after a sublethal (4.4 +/- 1.6 ng/ml) or lethal (40.9 +/- 3.8 ng/ml) dose, respectively. TNF-alpha injection induced a modest rise in LIF concentrations, peaking after 6 h (228 +/- 46 pg/ml). Circulating LIF correlated with plasma levels of IL-6, both after E. coli challenge (Spearman Rank coefficient of correlation (r) = 0.849, p<0.001), as well as upon TNF-alpha injection (r=0.863, p<0.001). Moreover, the E. coli-induced release of either cytokine was reduced 6- to 10-fold after pretreatment with anti-TNF mAb, except in one nonsurviving animal, which exhibited a progressive increase of LIF and IL-6 levels despite the absence of TNF immunoreactivity. These results show that TNF-alpha is an intermediate factor in concerted release of LIF and IL-6 in vivo, and indicate that the enhanced elaboration of these cytokines may predict disease outcome in severe sepsis.