IL-12-deficient mice are defective in IFN gamma production and type 1 cytokine responses

IL-12 is a cytokine that can exert regulatory effects on T and NK cells and promote Th1 responses. To delineate further the physiologic role of IL-12 in immunity, mice deficient for this cytokine were generated. IL-12-deficient mice were impaired but not completely lacking in the ability to produce IFN gamma following endotoxin administration and to mount a Th1 response in vivo, as measured by antigen-induced IFN gamma secretion by immune lymph node cells in vitro. In contrast, secretion of IL-4 was enhanced, while proliferation and secretion of IL-2 and IL-10 were normal following antigen stimulation. DTH responses were significantly reduced in IL-12-deficient mice, but no defect in allogeneic CTL responses was observed. These results indicate that IL-12 plays an essential role in regulating IFN gamma production and in facilitating normal DTH responses. However, other phenomena associated with Th1 responses and cell-mediated immunity, i.e., IL-2 secretion and CTL generation, were not compromised in the absence of IL-12.

Structure and function of enzymes involved in the biosynthesis of phenylpropanoids

As a major component of plant specialized metabolism, phenylpropanoid biosynthetic pathways provide anthocyanins for pigmentation, flavonoids such as flavones for protection against UV photodamage, various flavonoid and isoflavonoid inducers of Rhizobium nodulation genes, polymeric lignin for structural support and assorted antimicrobial phytoalexins. As constituents of plant-rich diets and an assortment of herbal medicinal agents, the phenylpropanoids exhibit measurable cancer chemopreventive, antimitotic, estrogenic, antimalarial, antioxidant and antiasthmatic activities. The health benefits of consuming red wine, which contains significant amounts of 3,4',5-trihydroxystilbene (resveratrol) and other phenylpropanoids, highlight the increasing awareness in the medical community and the public at large as to the potential dietary importance of these plant derived compounds. As recently as a decade ago, little was known about the three-dimensional structure of the enzymes involved in these highly branched biosynthetic pathways. Ten years ago, we initiated X-ray crystallographic analyses of key enzymes of this pathway, complemented by biochemical and enzyme engineering studies. We first investigated chalcone synthase (CHS), the entry point of the flavonoid pathway, and its close relative stilbene synthase (STS). Work soon followed on the O-methyl transferases (OMTs) involved in modifications of chalcone, isoflavonoids and metabolic precursors of lignin. More recently, our groups and others have extended the range of phenylpropanoid pathway structural investigations to include the upstream enzymes responsible for the initial recruitment of phenylalanine and tyrosine, as well as a number of reductases, acyltransferases and ancillary tailoring enzymes of phenylpropanoid-derived metabolites. These structure-function studies collectively provide a comprehensive view of an important aspect of phenylpropanoid metabolism. More specifically, these atomic resolution insights into the architecture and mechanistic underpinnings of phenylpropanoid metabolizing enzymes contribute to our understanding of the emergence and on-going evolution of specialized phenylpropanoid products, and underscore the molecular basis of metabolic biodiversity at the chemical level. Finally, the detailed knowledge of the structure, function and evolution of these enzymes of specialized metabolism provide a set of experimental templates for the enzyme and metabolic engineering of production platforms for diverse novel compounds with desirable dietary and medicinal properties.

Targeted disruption of the MHC class II Aa gene in C57BL/6 mice

The MHC class II gene Aa was disrupted by targeted mutation in embryonic stem (ES) cells derived from C57BL/6 mice to prevent expression of MHC class II molecules. Contrary to previous reports, the effect of the null-mutation on T cell development was investigated in C57BL/6 mice, which provide a defined genetic background. The complete lack of cell surface expression of MHC class II molecules in B6-Aa0/Aa0 homozygous mutant mice was directly demonstrated by cytofluorometric analysis using anti-Ab and anti-Ia specific mAbs. Development of CD4+CD8- T cells in the thymus was largely absent except for a small population of thymocytes expressing high levels of CD4 together with low amounts of CD8. The majority of these cells express the TCR at high density. Although mature CD4+CD8- T cells were undetectable in the thymus, some T cells with a CD4+CD8-TCRhigh phenotype were found in lymph nodes and spleen. Peripheral T cells from the mutant mice can be polyclonally activated in vitro with the mitogen concanavalin A. However, they could not be stimulated with staphylococcal enterotoxin B in autologous lymphocyte reactions, thereby demonstrating the absence of MHC class II expression in these mice. Peripheral B cells in B6-Aa0/Aa0 mutants were functional and responded to the T cell independent antigen levan by the production of antigen-specific IgM antibodies similar to wild-type cells. The B6-Aa0/Aa0 mutant mice described in this study represent an important tool to investigate the involvement of MHC class II molecules in lymphocyte maturation and the immune response.

Alternate cardiovascular baseline assessment techniques: vanilla or resting baseline

The accurate evaluation of cardiovascular reactions to psychological challenge requires stable baselines against which change can be evaluated. When more than one challenge is employed, the recovery of this baseline becomes important in order to avoid carryover effects. Resting periods, even those of 20 min or more, do not guarantee baseline stability. We compared a 20-min resting condition and a new form of baseline condition in 48 college men using video tasks as the psychological challenges. The new form was a minimally demanding color detection task, termed the "vanilla" baseline condition. A 10-min version and a 20-min version of this condition were tested. Comparisons to 10-min resting baselines were made using our prior work and values from the literature. Vanilla baseline conditions were shown to be equal to or better than resting baseline conditions using criteria of between- and within-baseline stability, amplitude and significance of responsivity, and generalizability between sessions on separate days. Ten-minute resting baselines also showed acceptable stability, questioning the value of lengthy baselines. The good performance of the 10-min vanilla baseline in initial and replication samples supported its utility for estimating baselines for many purposes.

Teratocarcinoma stem cells and early mouse embryos contain only a single major lamin polypeptide closely resembling lamin B

The nuclear lamina in adult mammalian somatic cells is composed of three major proteins, lamins A, B, and C. The expression of these proteins during the differentiation of teratocarcinomas and mouse embryogenesis is described. Embryos up to day 8 of gestation and embryonal carcinoma (EC) cells express only a single lamin species closely resembling, if not identical to, lamin B. Lamins A and/or C were detected in fertilized eggs, but disappear during the first 2-4 cleavage divisions, only reappearing in 8 day post-implantation embryos. These two lamins are absent from EC cells, but are strongly expressed in some of their derivatives. These results show that cells of the early mouse embryo do not have a functional requirement for lamins A and C and imply that the structural organization of the nucleus may change fundamentally during embryogenesis.

Multiple mutations in highly conserved residues are found in mildly affected cystic fibrosis patients

We have identified three different point mutations in the coding region of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Each mutation segregates with the disease in two- or three-generation pedigrees and is not found on the normal chromosome of any documented cystic fibrosis carrier. One of the mutations is found in two independent families that contain at least one individual with a mild course of disease. All of these alterations replace charged amino acids with less polar residues and are found in the putative transmembrane sections of the molecule. The mutated amino acids are found to be conserved in both rodents and amphibians and lie in a region of CFTR that is believed to form a channel in the membrane. Although these alterations are rare, they provide important clues to functionally important regions of the molecule.

Structure of the rat osteocalcin gene and regulation of vitamin D-dependent expression

The osteocalcin gene encodes a 6-kDa polypeptide, which represents one of the most abundant noncollagenous bone proteins, and the present studies establish that osteocalcin mRNA is detected only in bone tissue. An osteocalcin gene was isolated from a rat genomic DNA library, and sequence analysis indicated that the mRNA is represented in a 953-nucleotide segment of DNA consisting of four exons and three introns. A modular organization of the 5' flanking sequences of the gene is reflected by the presence of at least three classes of regulatory elements, which include the following: (i) RNA polymerase II canonical sequences; (ii) a series of consensus sequences for hormone receptor binding sites and cyclic nucleotide responsive elements consistent with physiologic expression of the osteocalcin gene; and (iii) a 24-nucleotide sequence in the proximal promoter region with a CAAT motif as a central element. We have designated this highly conserved sequence as an "osteocalcin box" since only 2 nucleotide substitutions are found in the rat and human osteocalcin genes. We have demonstrated two factors regulating osteocalcin gene expression. First, a 200-fold increase occurs in normal fetal calvaria osteoblasts producing a mineralizing matrix, compared to confluent osteoblasts in a nonmineralizing matrix. Second, contained within the 600 nucleotides immediately upstream from the transcription start site are sequences that support a 10-fold stimulated transcription of the gene by 1,25-dihydroxyvitamin D.

Activation of MHC class I, II, and CD40 gene expression by histone deacetylase inhibitors

Epigenetic mechanisms are involved in regulating chromatin structure and gene expression through repression. In this study, we show that histone deacetylase inhibitors (DAIs) that alter the acetylation of histones in chromatin enhance the expression of several genes on tumor cells including: MHC class I, II, and the costimulatory molecule CD40. Enhanced transcription results in a significant increase in protein expression on the tumor cell surface, and expression can be elicited on some tumors that are unresponsive to IFN-gamma. The magnitude of induction of these genes cannot be explained by the effect of DAIs on the cell cycle or enhanced apoptosis. Induction of class II genes by DAIs was accompanied by activation of a repressed class II transactivator gene in a plasma cell tumor but, in several other tumor cell lines, class II was induced in the apparent absence of class II transactivator transcripts. These findings also suggest that the abnormalities observed in some tumors in the expression of genes critical to tumor immunity may result from epigenetic alterations in chromatin and gene regulation in addition to well-established mutational mechanisms.

Mechanical Ventilation Management during Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome. An International Multicenter Prospective Cohort

Rationale: Current practices regarding mechanical ventilation in patients treated with extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome are unknown.Objectives: To report current practices regarding mechanical ventilation in patients treated with ECMO for severe acute respiratory distress syndrome (ARDS) and their association with 6-month outcomes.Methods: This was an international, multicenter, prospective cohort study of patients undergoing ECMO for ARDS during a 1-year period in 23 international ICUs.Measurements and Main Results: We collected demographics, daily pre- and per-ECMO mechanical ventilation settings and use of adjunctive therapies, ICU, and 6-month outcome data for 350 patients (mean ± SD pre-ECMO Pa_O2/Fi_O2 71 ± 34 mm Hg). Pre-ECMO use of prone positioning and neuromuscular blockers were 26% and 62%, respectively. Vt (6.4 ± 2.0 vs. 3.7 ± 2.0 ml/kg), plateau pressure (32 ± 7 vs. 24 ± 7 cm H₂O), driving pressure (20 ± 7 vs. 14 ± 4 cm H₂O), respiratory rate (26 ± 8 vs. 14 ± 6 breaths/min), and mechanical power (26.1 ± 12.7 vs. 6.6 ± 4.8 J/min) were markedly reduced after ECMO initiation. Six-month survival was 61%. No association was found between ventilator settings during the first 2 days of ECMO and survival in multivariable analysis. A time-varying Cox model retained older age, higher fluid balance, higher lactate, and more need for renal-replacement therapy along the ECMO course as being independently associated with 6-month mortality. A higher Vt and lower driving pressure (likely markers of static compliance improvement) across the ECMO course were also associated with better outcomes.Conclusions: Ultraprotective lung ventilation on ECMO was largely adopted across medium- to high-case volume ECMO centers. In contrast with previous observations, mechanical ventilation settings during ECMO did not impact patients' prognosis in this context.

The challenge of patients' unmet palliative care needs in the final stages of chronic illness

BACKGROUND

There is consensus in the literature that the end of life care for patients with chronic illness is suboptimal, but research on the specific needs of this population is limited.

AIM

This study aimed to use a mixed methodology and case study approach to explore the palliative care needs of patients with a non-cancer diagnosis from the perspectives of the patient, their significant other and the clinical team responsible for their care. Patients (n = 18) had a diagnosis of either end-stage heart failure, renal failure or respiratory disease.

METHODS

The Short Form 36 and Hospital and Anxiety and Depression Questionnaire were completed by all patients. Unstructured interviews were (n = 35) were conducted separately with each patient and then their significant other. These were followed by a focus group discussion (n = 18) with the multiprofessional clinical team. Quantitative data were analysed using simple descriptive statistics and simple descriptive statistics. All qualitative data were taped, transcribed and analysed using Colaizzi's approach to qualitative analysis.

FINDINGS

Deteriorating health status was the central theme derived from this analysis. It led to decreased independence, social isolation and family burden. These problems were mitigated by the limited resources at the individual's disposal and the availability of support from hospital and community services. Generally resources and support were perceived as lacking. All participants in this study expressed concerns regarding the patients' future and some patients described feelings of depression or acceptance of the inevitability of imminent death.

CONCLUSION

Patients dying from chronic illness in this study had many concerns and unmet clinical needs. Care teams were frustrated by the lack of resources available to them and admitted they were ill-equipped to provide for the individual's holistic needs. Some clinicians described difficulty in talking openly with the patient and family regarding the palliative nature of their treatment. An earlier and more effective implementation of the palliative care approach is necessary if the needs of patients in the final stages of chronic illness are to be adequately addressed.

Sarcopenia during COVID-19 lockdown restrictions: long-term health effects of short-term muscle loss

The COVID-19 pandemic is an extraordinary global emergency that has led to the implementation of unprecedented measures in order to stem the spread of the infection. Internationally, governments are enforcing measures such as travel bans, quarantine, isolation, and social distancing leading to an extended period of time at home. This has resulted in reductions in physical activity and changes in dietary intakes that have the potential to accelerate sarcopenia, a deterioration of muscle mass and function (more likely in older populations), as well as increases in body fat. These changes in body composition are associated with a number of chronic, lifestyle diseases including cardiovascular disease (CVD), diabetes, osteoporosis, frailty, cognitive decline, and depression. Furthermore, CVD, diabetes, and elevated body fat are associated with greater risk of COVID-19 infection and more severe symptomology, underscoring the importance of avoiding the development of such morbidities. Here we review mechanisms of sarcopenia and their relation to the current data on the effects of COVID-19 confinement on physical activity, dietary habits, sleep, and stress as well as extended bed rest due to COVID-19 hospitalization. The potential of these factors to lead to an increased likelihood of muscle loss and chronic disease will be discussed. By offering a number of home-based strategies including resistance exercise, higher protein intakes and supplementation, we can potentially guide public health authorities to avoid a lifestyle disease and rehabilitation crisis post-COVID-19. Such strategies may also serve as useful preventative measures for reducing the likelihood of sarcopenia in general and in the event of future periods of isolation.

Mesenchymal stromal cell-derived extracellular vesicles rescue radiation damage to murine marrow hematopoietic cells

Mesenchymal stromal cells (MSCs) have been shown to reverse radiation damage to marrow stem cells. We have evaluated the capacity of MSC-derived extracellular vesicles (MSC-EVs) to mitigate radiation injury to marrow stem cells at 4 h to 7 days after irradiation. Significant restoration of marrow stem cell engraftment at 4, 24 and 168 h post irradiation by exposure to MSC-EVs was observed at 3 weeks to 9 months after transplant and further confirmed by secondary engraftment. Intravenous injection of MSC-EVs to 500cGy exposed mice led to partial recovery of peripheral blood counts and restoration of the engraftment of marrow. The murine hematopoietic cell line, FDC-P1 exposed to 500cGy, showed reversal of growth inhibition, DNA damage and apoptosis on exposure to murine or human MSC-EVs. Both murine and human MSC-EVs reverse radiation damage to murine marrow cells and stimulate normal murine marrow stem cell/progenitors to proliferate. A preparation with both exosomes and microvesicles was found to be superior to either microvesicles or exosomes alone. Biologic activity was seen in freshly isolated vesicles and in vesicles stored for up to 6 months in 10% dimethyl sulfoxide at -80 °C. These studies indicate that MSC-EVs can reverse radiation damage to bone marrow stem cells.

Platelet size in stroke patients

BACKGROUND AND PURPOSE

Large platelets are more reactive, produce more prothrombotic factors, and aggregate more easily. Platelet size can be readily estimated using automated analyzers, although accurate estimation depends on precise methodology. The disparate results from previous studies of mean platelet volume in cerebral ischemia may be explained by varying methodology. We have studied these variables using a precise methodology in an unselected group of stroke patients and compared them with data from age- and sex-matched control subjects.

METHODS

We studied 58 stroke patients consecutively admitted to a geriatric medical unit. Platelet variables were measured in the acute (< 48 hours after stroke) and chronic (> 6 months) phases of cerebral ischemia and compared with control variables. Control patients, admitted to the same unit, were of similar age and sex and without evidence of acute vascular events.

RESULTS

Mean platelet volume was higher in acute stroke (11.3 compared with 10.1 fL in control subjects; P < .001, Student's t test). In addition, platelet count was reduced in stroke patients (255 x 10(9)/L) compared with control subjects (299 x 10(9)/L; P < .01). Repeated measurements of mean platelet volume and platelet count in available survivors showed no significant change from the acute phase. Platelet changes did not relate to outcome measured at 6 months.

CONCLUSIONS

With the use of more precise methodology, these findings show that an increase in mean platelet volume and a reduction in platelet count are features of both the acute and nonacute phases of cerebral ischemia. It is possible that these changes precede the vascular event, and further studies are warranted.

Early discharge for patients with exacerbations of chronic obstructive pulmonary disease: a randomized controlled trial

BACKGROUND

We have previously reported the use of a hospital based respiratory nurse service (Acute Respiratory Assessment Service, ARAS) to support home treatment of patients with exacerbations of chronic obstructive pulmonary disease (COPD). A controlled trial was undertaken to compare early discharge with home treatment supported by respiratory nurses with conventional hospital management of patients admitted with exacerbations of COPD.

METHODS

Patients with COPD admitted as emergencies were identified the next working day. They were eligible for inclusion in the study if the differential diagnosis included an exacerbation of COPD, but were excluded if other medical conditions or acidotic respiratory failure required inpatient investigation or management. Of 360 patients reviewed, 209 were being assessed for other active medical problems and were excluded, 33 potential participants were already involved in research studies and so were ineligible, and 37 did not wish to participate in the study. Eighty one patients were randomised to receive conventional inpatient care (n=40) or to planned early discharge the next working day (n=41). Those discharged early continued treatment at home under the supervision of specialist respiratory nurses. Outcome measures were readmission, additional hospital days, and deaths within 60 days of initial admission. Process measures included number of visits, duration of follow up by the respiratory nurse, and additional treatment provided to support early discharge.

RESULTS

On an intention to treat basis, a policy of early discharge reduced inpatient stay from a mean of 6.1 (range 1-13) days with conventional management to 3.2 (1-16) days with an early discharge policy. Twelve patients (30% conventional management, 29.3% early discharge) were readmitted in each group giving a mean difference in readmission of 0.7% (95% CI of the difference -19.2 to 20.6). In the conventional management group readmitted patients spent a mean of 8.75 additional days in hospital compared with 7.83 days in the early discharge group, giving a mean difference of 0.92 days (95% CI of the difference -6.5 to 8.3). There were two deaths (5%) in the conventional management group and one (2.4%) in the early discharge group, a mean difference of 2.6% (95% CI of the difference -5.7 to 10.8).

CONCLUSIONS

Patients with acute exacerbations of COPD uncomplicated by acidotic respiratory failure or other medical problems can be discharged home earlier than is current practice with support by visiting respiratory nurses. No difference was found in the subsequent need for readmission.

Spectral and other physicochemical properties of submicron powders of hematite (alpha-Fe2O3), maghemite (gamma-Fe2O3), magnetite (Fe3O4), goethite (alpha-FeOOH), and lepidocrocite (gamma-FeOOH)

Spectral and other physicochemical properties were determined for a suite of submicron powders of hematite (alpha-Fe2O3), maghemite (gamma-Fe2O3), magnetite (Fe3O4), goethite (alpha-FeOOH), and lepidocrocite (gamma-FeOOH). The spectral reflectivity measurements were made between 0.35 and 2.20 micrograms over the temperature interval between about -110 degrees and 20 degrees C. Other physicochemical properties determined were mean particle diameter, particle shape, chemical composition, crystallographic phase, magnetic properties, and Mossbauer properties. Only the magnetite powders have significant departures from the stoichiometric phase; they are actually cation-deficient magnetites having down to about 18.0 wt % FeO as compared with 31.0 wt % FeO for stoichiometric magnetite. A structured absorption edge due to crystal field transitions and extending from weak absorption in the near-IR to intense absorption in the near-UV is characteristic of the ferric oxides and oxyhydroxides and is responsible for their intense color. Particularly for hematite, the number and position of the spectral features are consistent with significant splitting of the degenerate cubic levels by noncubic components of the crystal field. The position of the crystal-field band at lowest energy, assigned to the envelope of the components of the split cubic 4T1 level, is near 0.86, 0.91, 0.92, and 0.98 microgram at room temperature for hematite, goethite, maghemite, and lepidocrocite, respectively. Comparison with Mossbauer data suggests covalent character increases sequentially through the aforementioned series. The positions of the spectra features are relatively independent of temperature down to about -110 degrees C. The maximum shifts observed were on the order of about 0.02 microgram shortward for the ferric oxyhydroxides. Variations in the magnitude of the reflectivity of the hematite powders as a function of mean particle diameter are consistent with scattering theory. The absorption strength of the crystal-field bands increases with increasing mean particle diameter over the range 0.1-0.8 micrometer; visually this corresponds to a change in color from orange to deep purple. The position of the split cubic 4T1 band shifts longward by about 0.02 micrometer with decreasing mean particle diameter over the same range; this trend is consistent with wavelength-dependent scattering. The cation-deficient magnetite powders are very strong absorbers throughout the near-UV, visible and near-IR; their spectral properties are independent of temperature between about -110 and 20 degrees C.

Rituximab in Combination With Fludarabine Chemotherapy in Low-Grade or Follicular Lymphoma

Purpose

To evaluate the safety and efficacy of fludarabine plus rituximab in treatment-naïve or relapsed patients with low-grade and/or follicular non-Hodgkin's lymphoma.

Patients and Methods

This was an open-label, single-arm, single-center phase II study enrolling 40 patients. During the first week of the study, patients received two infusions of rituximab 375 mg/m2 administered 4 days apart. Seventy-two hours after the second infusion of rituximab, patients received the first of six cycles of fludarabine chemotherapy (25 mg/m2/d for 5 days on a 28-day cycle). Single infusions of rituximab were administered 72 hours before the second, fourth, and sixth cycles of fludarabine, and two infusions of rituximab were given 4 weeks after the last cycle of fludarabine. Treatment duration was 26 weeks.

Results

An overall response rate of 90% (80% complete response rate) was achieved in the intent-to-treat population. Similar response rates were seen in treatment-naïve and previously treated patients. The median duration of response has not been reached at 40+ months. The median follow-up time in this study is 44 months (range, 15 to 66 months). In patients positive for the 14;18 translocation in blood and/or marrow at enrollment, molecular remission was achieved in 88% of cases, with patients remaining negative for up to 4 years to date. Hematologic toxicity was manageable, and except for a 15% incidence of herpes simplex/zoster infections, infectious complications were rare. Nonhematologic toxicities were minimal.

Conclusion

Rituximab plus fludarabine was well tolerated and associated with an excellent complete response rate, including molecular remissions, in patients with low-grade or follicular lymphoma.

Comparison of laser speckle and laser Doppler perfusion imaging: measurement in human skin and rabbit articular tissue

Laser Doppler perfusion imaging (LDI) is currently used in a variety of clinical applications, however, LDI instruments produce images of low resolution and have long scan times. A new optical perfusion imager using a laser speckle measurement technique and its use for in vivo blood flow measurements are described. Measurements of human skin and surgically exposed rabbit tissue made using this instrument were compared with a commercial laser Doppler perfusion imaging instrument. Results from blood flow measurements showed that the laser speckle imager measured an 11-67% decrease in blood flow under arterial occlusion. Under similar conditions, the laser Doppler imager measured blood flow decreases of 21-63%. In comparison with LDI, it was observed that the higher temporal resolution of the laser speckle imager was more sensitive to measuring the hyperaemic response immediately following occlusion. This in vivo study demonstrated some of the several advantages laser speckle imaging has over conventional LDI, making the new instrument more versatile in a clinical environment.

Phase I study of topotecan for pediatric patients with malignant solid tumors

PURPOSE

To determine the dose-limiting toxicity and potential efficacy of topotecan in pediatric patients with refractory malignant solid tumors.

PATIENTS AND METHODS

In this phase I clinical trial, 27 patients received topotecan 0.75-1.9 mg/m2 by continuous intravenous infusion daily for 3 days. Fifty-three treatment courses were given to these patients.

RESULTS

Myelosuppression was the dose-limiting toxicity at levels of 1.3 to 1.9 mg/m2 for 3 days, requiring significant support with transfused packed RBCs and platelets. Myelosuppression was variable in severity at the 1.0-mg/m2 dosage level; thus, additional patients were treated with this dosage, followed by human recombinant granulocyte-colony stimulating factor (G-CSF). Other toxicities were not significant. One patient with neuroblastoma had a complete response that lasted for 8 months. Stable disease activity was recorded for other patients with neuroblastoma, rhabdomyosarcoma, and islet cell carcinoma. Pharmacokinetic studies showed that topotecan plasma concentrations ranged from 1.6 to 7.5 ng/mL during infusions of 1.0 mg/m2/d, and that there was a biphasic plasma distribution with a mean terminal half-life of 2.9 +2- 1.0 hours.

CONCLUSION

Topotecan is a promising anticancer agent that deserves phase II testing in pediatric solid tumors. We recommend that pediatric phase II topotecan trials use 1.0 mg/m2/d for 3 days as a constant intravenous infusion, followed by G-CSF for 14 days, and that these treatment courses be repeated every 21 days.

A systems-based investigation into vitamin D and skeletal muscle repair, regeneration, and hypertrophy

Skeletal muscle is a direct target for vitamin D. Observational studies suggest that low 25[OH]D correlates with functional recovery of skeletal muscle following eccentric contractions in humans and crush injury in rats. However, a definitive association is yet to be established. To address this gap in knowledge in relation to damage repair, a randomised, placebo-controlled trial was performed in 20 males with insufficient concentrations of serum 25(OH)D (45 ± 25 nmol/l). Prior to and following 6 wk of supplemental vitamin D3 (4,000 IU/day) or placebo (50 mg of cellulose), participants performed 20 × 10 damaging eccentric contractions of the knee extensors, with peak torque measured over the following 7 days of recovery. Parallel experimentation using isolated human skeletal muscle-derived myoblast cells from biopsies of 14 males with low serum 25(OH)D (37 ± 11 nmol/l) were subjected to mechanical wound injury, which enabled corresponding in vitro studies of muscle repair, regeneration, and hypertrophy in the presence and absence of 10 or 100 nmol 1α,25(OH)2D3. Supplemental vitamin D3 increased serum 25(OH)D and improved recovery of peak torque at 48 h and 7 days postexercise. In vitro, 10 nmol 1α,25(OH)2D3 improved muscle cell migration dynamics and resulted in improved myotube fusion/differentiation at the biochemical, morphological, and molecular level together with increased myotube hypertrophy at 7 and 10 days postdamage. Together, these preliminary data are the first to characterize a role for vitamin D in human skeletal muscle regeneration and suggest that maintaining serum 25(OH)D may be beneficial for enhancing reparative processes and potentially for facilitating subsequent hypertrophy.

Characterization of the mouse Men1 gene and its expression during development

The gene responsible for multiple endocrine neoplasia type 1 (MEN1), a heritable predisposition to endocrine tumours in man, has recently been identified. Here we have characterized the murine homologue with regard to cDNA sequence, genomic structure, expression pattern and chromosomal localisation. The murine Men1 gene spans approximately 6.7 kb of genomic DNA and is comprised of 10 exons with similar genomic structure to the human locus. It was mapped to the pericentromeric region of mouse chromosome 19, which is conserved with the human 11q13 band where MEN1 is located. The predicted protein is 611 amino acids in length and overall is 97% homologous to the human orthologue. The 45 reported MEN1 mutations which alter or delete a single amino acid in human all occur at conserved residues, thereby supporting their functional significance. Two transcripts of approximately 3.2 and 2.8 kb were detected in both embryonal and adult murine tissues, resulting from alternative splicing of intron 1. By RNA in situ hybridization and Northern analysis the spatiotemporal expression pattern of Men1 was determined during mouse development. Men1 gene activity was detected already at gestational day 7. At embryonic day 14 expression was generally high throughout the embryo, while at day 17 the thymus, skeletal muscle, and CNS showed the strongest signal. In selected tissues from postnatal mouse Men1 was detected in all tissues analysed and was expressed at high levels in cerebral cortex, hippocampus, testis, and thymus. In brain the menin protein was detected mainly in nerve cell nuclei, whereas in testis it appeared perinuclear in spermatogonia. These results show that Men1 expression is not confined to organs affected in MEN1, suggesting that Men1 has a significant function in many different cell types including the CNS and testis.

Preclinical trials in autosomal dominant AD: implementation of the DIAN-TU trial

The Dominantly Inherited Alzheimer's Network Trials Unit (DIAN-TU) was formed to direct the design and management of interventional therapeutic trials of international DIAN and autosomal dominant Alzheimer's disease (ADAD) participants. The goal of the DIAN-TU is to implement safe trials that have the highest likelihood of success while advancing scientific understanding of these diseases and clinical effects of proposed therapies. The DIAN-TU has launched a trial design that leverages the existing infrastructure of the ongoing DIAN observational study, takes advantage of a variety of drug targets, incorporates the latest results of biomarker and cognitive data collected during the observational study, and implements biomarkers measuring Alzheimer's disease (AD) biological processes to improve the efficiency of trial design. The DIAN-TU trial design is unique due to the sophisticated design of multiple drugs, multiple pharmaceutical partners, academics servings as sponsor, geographic distribution of a rare population and intensive safety and biomarker assessments. The implementation of the operational aspects such as home health research delivery, safety magnetic resonance imagings (MRIs) at remote locations, monitoring clinical and cognitive measures, and regulatory management involving multiple pharmaceutical sponsors of the complex DIAN-TU trial are described.

Thymocytes in Thy-1-/- mice show augmented TCR signaling and impaired differentiation

Thy-1, a single variable-like immunoglobulin superfamily domain anchored in the plasma membrane by a glycosyl phosphaditylinositol tail [1], is a major surface glycoprotein in adult mammalian neurons and rodent thymocytes [2]; the function of Thy-1 has remained enigmatic since its discovery [3]. Studies in vitro have implicated Thy-1 in homotypic and heterotypic cell-cell interactions [2,4]. Ligation of Thy-1 initiates transmembrane signaling pathways that lead to diverse physiological outcomes in different cells [2,5-7]. In rodents, Thy-1 is highly expressed on the surface of CD4+CD8+ double-positive immature thymocytes and downregulated in mature T cells. Here, we report that thymocytes from Thy-1-/- mice [8] had altered cell-cell contacts, and hyperresponsiveness to T-cell receptor (TCR) triggering as demonstrated by the heightened activation of p56lck, phosphorylation of TCR subunits, Ca2+ fluxes and cell proliferation. Thy-1-/- thymocytes exhibited impaired maturation from the double positive to single positive stage of thymocyte development, possibly due to inappropriate negative selection, and were prone to T lymphomas in aged mice. These observations indicate that Thy-1 negatively regulates TCR-mediated signaling and controls activation thresholds during thymocyte differentiation.

IL-12-deficient mice are defective but not devoid of type 1 cytokine responses

Interleukin-12 (IL-12) has been described as a pivotal molecule in the immune response based in part on its ability to influence the differentiation of T helper (Th) cells into a type 1 (Th1) phenotype. This event is crucial in that appropriate differentiation of naive T cells can determine susceptibility or resistance to given pathogens by influencing the balance between cellular and humoral immunity. In order to further delineate the role of IL-12 in the immune response, we generated mice deficient for this cytokine. IL-12 knockout mice were viable, fully fertile, and displayed no obvious developmental abnormalities. Upon immunological analysis, these mice demonstrated an impaired ability to effect a Th1 response as well as an impaired ability to produce interferon-gamma in response to endotoxin in vivo. These data establish an essential role for IL-12 in the generation of optimal Th1 responses in vivo, but weak responses can occur independently of IL-12.

The risk of depression, suicidal ideation and suicide attempt in patients with psoriasis, psoriatic arthritis or ankylosing spondylitis

BACKGROUND

Sparse information is available concerning mental health issues in psoriasis, psoriatic arthritis (PsA) and ankylosing spondylitis (AS) patients.

OBJECTIVE

To estimate risk of depression, suicidal ideation and suicide attempt in patients with psoriasis, PsA and AS, respectively, compared with the general population.

METHODS

This population-based cohort study analysed 36 214 psoriasis patients, 5138 PsA patients and 1878 AS patients who were frequency-matched with a general population cohort. Annual incidence rate of depression, suicidal ideation and suicide attempt was calculated separately for psoriasis, PsA and AS.

RESULTS

There was an increased risk of depression in the three cohorts; adjusted IRR: psoriasis, 1.14 (95% CI, 1.11, 1.17); PsA, 1.22 (95% CI, 1.16, 1.29); AS, 1.34 (95% CI, 1.23, 1.47). There was no significantly increased risk for suicidal ideations or suicide attempt among psoriasis, PsA or AS patients.

LIMITATIONS

Patients were not excluded if previously diagnosed with depression, suicidal ideation or suicide attempt. Suicide attempt and completed suicide analyses were not adjusted for presence of depression. Use of systemic psoriasis treatment to measure severe psoriasis could lead to psoriasis severity misclassification.

CONCLUSION

The risk of depression, but not suicidal ideation or suicide attempt, was significantly increased in patients with psoriasis, PsA and AS.