Low copy numbers of complement C4 and C4A deficiency are risk factors for myositis, its subgroups and autoantibodies

BACKGROUND

Idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases characterised by myositis-related autoantibodies plus infiltration of leucocytes into muscles and/or the skin, leading to the destruction of blood vessels and muscle fibres, chronic weakness and fatigue. While complement-mediated destruction of capillary endothelia is implicated in paediatric and adult dermatomyositis, the complex diversity of complement C4 in IIM pathology was unknown.

METHODS

We elucidated the gene copy number (GCN) variations of total C4, C4A and C4B, long and short genes in 1644 Caucasian patients with IIM, plus 3526 matched healthy controls using real-time PCR or Southern blot analyses. Plasma complement levels were determined by single radial immunodiffusion.

RESULTS

The large study populations helped establish the distribution patterns of various C4 GCN groups. Low GCNs of C4T (C4T=2+3) and C4A deficiency (C4A=0+1) were strongly correlated with increased risk of IIM with OR equalled to 2.58 (2.28-2.91), p=5.0×10^-53 for C4T, and 2.82 (2.48-3.21), p=7.0×10^-57 for C4A deficiency. Contingency and regression analyses showed that among patients with C4A deficiency, the presence of HLA-DR3 became insignificant as a risk factor in IIM except for inclusion body myositis (IBM), by which 98.2% had HLA-DR3 with an OR of 11.02 (1.44-84.4). Intragroup analyses of patients with IIM for C4 protein levels and IIM-related autoantibodies showed that those with anti-Jo-1 or with anti-PM/Scl had significantly lower C4 plasma concentrations than those without these autoantibodies.

CONCLUSIONS

C4A deficiency is relevant in dermatomyositis, HLA-DRB1*03 is important in IBM and both C4A deficiency and HLA-DRB1*03 contribute interactively to risk of polymyositis.

How to assess severity in males with eating disorders? The DSM-5 severity index versus severity based on drive for thinness

Introduction

The Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) introduced severity indices for Eating Disorders (ED).

Objectives

This study assessed in a male ED sample the DSM-5 severity indices for Anorexia Nervosa (AN), Bulimia Nervosa (BN) and Binge Eating Disorder (BED) and compared them to an alternative transdiagnostic drive for thinness (DT) severity category and a combined DSM-5/DT severity categorization

Methods

178 males with EDs were classified using: a.) a DT categorisation based on the EDI-2 DT subscale; b.) the DSM-5 severity categories for AN, BN and BED and c.) a combination of the DT and the DSM-5 severity categorisation. These severity classifications were then compared based on psychopathology and personality.

Results

For the DSM-5 severity indices, the “mild” category was most prevalent for AN and BN, and the “moderate to extreme” group for BED. For the EDI-2 DT severity classification, the “mild” category was overrepresented in all subtypes. For the combined DSM-5/DT categorization, the “mild combined” severity group was the most prevalent for AN, while for BN and BED the “severe/extreme” combined group was most prevalent. Clinically significant findings were strongest for the DT categorization followed by the combined DSM-5/DT approach. Almost non-significant findings were revealed for the DSM-5 severity categories for all ED subtypes. These findings were most pronounced for AN and BN and almost non-existent for BED.

Conclusions

Our findings provide support for DT as an alternative transdiagnostic severity category for EDs in males that may be more meaningful than the DSM-5 severity indices for AN and BN, but not BED.

Disclosure

No significant relationships.

A systematic review and meta-analysis on the DSM-5 severity specifiers for eating disorders

Introduction

The DSM-5 introduced severity indicies for the first time.

Objectives

We conducted a systematic review and synthesis the frequency of each DSM-5 severity categories (i.e., mild, moderate, severe and extreme severe) for Anorexia Nervosa (AN), Bulimia Nervosa (BN) and Binge Eating Disorders (BED), and to evaluate studies that assess the clinical utility of these severity specifiers for all eating disorders (ED) subtypes.

Methods

Five databases (EMBASE, MEDLINE, PsycARTICLES, PsycINFO, and ProQuest) were used to identify for both academic and grey literature published from 2013 until July 8, 2020. Twenty-five studies were retrieved for the systematic review based on the inclusion and exclusion criteria, and up to six studies were qualified for meta-analysis

Results

We found limited support for the current DSM-5 severity ratings for all ED indices, as the majority of ED severity groups were not significantly distinguishable in overall ED psychopathology (mean effect size ranged from .02 to .5). The value of the DSM-5 severity ratings was further devalued as 56.91% to 80.52% of individuals with AN, BN, and BED were categorized into mild and moderate groups. However, there was significant heterogeneity between the studies (p< .001), and some of these heterogeneities were explained by differences in study settings and measurement of eating disorder psychopathology.

Conclusions

Overall, the current study provided little support for the DSM-5 severity ratings for EDs, thus it is suggested that further exploration in alternative severity classification approach is needed.

Disclosure

No significant relationships.

Do women with differing levels of trait eating pathology experience daily stress and body dissatisfaction differently?

Introduction

Studies have suggested that stress predicts both body dissatisfaction (BD) and disordered eating (DE) patterns. However, the mechanisms of this process are not entirely clear and could be elucidated through further exploration in daily life.

Objectives

The purpose of this study was to 1) explore the concurrent and lagged relationship between stress and BD in the daily life of individuals with differing levels of trait eating pathology (EP) and 2) to investigate whether maladaptive coping moderated these relationships.

Methods

107 female participants (mean age = 26.92) completed an online survey about stress, coping strategies and trait EP. Participants used a smartphone app to report on state stress, BD and DE six times a day for seven days

Results

Individuals with elevated trait EP experienced a significantly higher frequency of stress events (b = 0.04). Participants’ use of maladaptive coping significantly increased state stress (b = 0.41), but was not moderated by EP. Participants’ state stress and BD measured at the same time point (concurrent assessment) were significantly related (b = 0.13). Either stress or BD at the previous time point did not significantly predict changes in the other (lagged assessment, b = 0.02, b = -0.09, respectively). The aforementioned state-based associations were not moderated by trait EP

Conclusions

Women with more severe EP were found to experience stress more frequently. Maladaptive coping strategies were related to stress, but not moderated by EP. The association between stress and BD from concurrent but not lagged assessment highlights the importance of assessing and targeting momentary stress levels.

Disclosure

No significant relationships.

Factors affecting radiotherapy prescribing patterns in the post-mastectomy setting

Background

Radiation therapy (rt) after mastectomy for breast cancer can improve survival outcomes, but has been associated with inferior cosmesis after breast reconstruction. In the literature, rt dose and fractionation schedules are inconsistently reported. We sought to determine the pattern of rt prescribing practices in a provincial rt program for patients treated with mastectomy and reconstruction.

Methods

Women diagnosed with stages 0-iii breast cancer between January 2012 and December 2013 and treated with curative-intent rt were identified from a clinicopathology database. Patient demographic, tumour, and treatment information were extracted. Of the identified patients, those undergoing mastectomy were the focus of the present analysis.

Results

Of 4016 patients identified, 1143 (28%) underwent mastectomy. The patients treated with mastectomy had a median age of 57 years, and 37% of them underwent reconstruction. Treatment with more than 16 fractions of rt was associated with autologous reconstruction [odds ratio (or): 37.2; 95% confidence interval (ci): 11.2 to 123.7; p < 0.001], implant reconstruction (or: 93.3; 95% ci: 45.3 to 192.2; p < 0.001), and treating centre. Hypofractionated treatment was associated with older age (or: 0.94; 95% ci: 0.92 to 0.96; p < 0.001), and living more than 400 km from a treatment centre (or: 0.37; 95% ci: 0.16 to 0.86; p = 0.02).

Conclusions

Prescribing practices in breast cancer patients undergoing mastectomy are influenced by reconstruction intent, age, nodal status, and distance from the treatment centre. Those factors should be considered when making treatment decisions.

Assessing post-radiotherapy handover notes from a family physician perspective

Background

Across our province, post-radiotherapy (rt) handover notes are sent to family physicians (fps) after rt. Based on previous fp feedback, we created a revised post-radiotherapy handover note with more information requested by fps. The purpose of this study was to determine whether the revised handover note improved the note as a communication aid.

Methods

Potential common and rare treatment side effects, oncologist contact information, and treatment intent were added to the revised handover note. Both versions were sent alongside a questionnaire to fps. Paired t-tests were carried out to compare satisfaction differences.

Results

There was a response rate of 37% for the questionnaires. Significantly greater clarity in the following categories was observed: responsibility for patient follow-up (mean score improvement of 1.2 on a 7-point Likert scale, p < 0.001), follow-up schedule (1.1, p < 0.001) as well as how and when to contact the oncologist (1.4, p = 0.001). Family physicians were also more content with how the institute transitioned care back to them (1.5, p = 0.012). Overall, fps were generally satisfied with the content of the revised post-rt handover note and noted improvement over the previous version. The frequency of investigations and institute supports initiated such as counselling services were suggested further additions.

Conclusions

The inclusion of potential treatment side effects, oncologist contact information, treatment intent and a well-laid out follow-up schedule were essential information needed by fps for an effective post-rt completion note. With these additions, the revised post-rt handover note showed significant improvement.

Intraoperative serum lactate is not a predictor of survival after glioblastoma surgery

BACKGROUND

Cancer cells can produce lactate in high concentrations. Two previous studies examined the clinical relevance of serum lactate as a biomarker in patients with brain tumors. Patients with high-grade tumors have higher serum concentrations of lactate than those with low-grade tumors. We hypothesized that serum lactic could be used of biomarker to predictor of survival in patients with glioblastoma (GB).

METHODS

This was a retrospective study. Demographic, lactate concentrations and imaging data from 275 adult patients with primary GB was included in the analysis. The progression free survival (PFS) and overall survival (OS) rates were compared in patients who had above and below the median concentrations of lactate. We also investigated the correlation between lactate concentrations and tumor volume. Multivariate analyses were conducted to test the association lactate, tumor volume and demographic variables with PFS and OS.

RESULTS

The median serum concentration of lactate was 2.3mmol/L. A weak correlation was found between lactate concentrations and tumor volume. Kaplan-Meier curves demonstrated similar survival in patients with higher or lower than 2.3mmol/L of lactate. The multivariate analysis indicated that the intraoperative levels of lactate were not independently associated with changes in survival. On another hand, a preoperative T1 volume was an independent predictor PFS (HR 95%CI: 1.41, 1.02-1.82, p=0.006) and OS (HR 95%CI: 1.47, 1.11-1.96, p=0.006).

CONCLUSION

This retrospective study suggests that the serum concentrations of lactate cannot be used as a biomarker to predict survival after GB surgery. To date, there are no clinically available serum biomarkers to determine prognosis in patients with high-grade gliomas. These tumors may produce high levels of lactic acid. We hypothesized that serum lactic could be used of biomarker to predictor of survival in patients with glioblastoma (GB). In this study, we collected perioperative and survival data from 275 adult patients with primary high-grade gliomas to determine whether intraoperative serum acid lactic concentrations can serve as a marker of prognosis. The median serum concentration of lactate was 2.3mmol/L. Our analysis indicated the intraoperative levels of lactate were not independently associated with changes in survival. This retrospective study suggests that the serum concentrations of lactate cannot be used as a biomarker to predict survival after GB surgery.

High-sensitivity C-reactive protein predicts adverse cardiovascular events in patients with Takayasu arteritis with coronary artery involvement

The study aimed to assess the association of high-sensitivity C-reactive protein (hsCRP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) to major adverse cardiovascular events (MACE) in Takayasu arteritis (TA) patients with coronary artery disease (CAD). Data on 60 TA patients with CAD and 60 age- and severity-matched patients with CAD hospitalized in Fuwai Hospital from 2005 to August 2014 were assessed. The clinical features, laboratory data, coronary angiographic findings, treatment, and follow-up outcomes were summarized retrospectively. MACE were defined as death from cardiac causes, myocardial infarction, nonfatal target vessel revascularization, or rehospitalization due to unstable or progressive angina. CAD patients had more atherogenic lipid and lipoprotein profiles such as lower levels of high-density lipoprotein cholesterol (HDL-C) (1.0 ± 0.2 vs. 1.3 ± 0.3 mmol/L, p = 0.01) and higher levels of low-density lipoprotein cholesterol (LDL-C) (2.5 ± 0.9 vs. 2.2 ± 1.1 mmol/L, p = 0.04) in contrast with TA-CAD patients. During a mean follow-up period of 3.2 years, 31 patients with Takayasu coronary arteritis reached the endpoint. Multivariate Cox proportional hazards model demonstrated that log(hsCRP) (HR = 5.3, 95 % CI = 1.1-27.8, p = 0.04) was a significant and independent predictor of MACE in patients with Takayasu coronary arteritis. Elevated baseline levels of hsCRP predict cardiovascular events, independent of other prognostic markers in TA-related CAD patients.

Characterisation of osteoarthritis in a small animal model of type 2 diabetes mellitus

Objectives

Our objective in this article is to test the hypothesis that type 2 diabetes mellitus (T2DM) is a factor in the onset and progression of osteoarthritis, and to characterise the quality of the articular cartilage in an appropriate rat model.

Methods

T2DM rats were obtained from the UC Davis group and compared with control Lewis rats. The diabetic rats were sacrificed at ages from six to 12 months, while control rats were sacrificed at six months only. Osteoarthritis severity was determined via histology in four knee quadrants using the OARSI scoring guide. Immunohistochemical staining was also performed as a secondary form of osteoarthritic analysis.

Results

T2DM rats had higher mean osteoarthritis scores than the control rats in each of the four areas that were analysed. However, only the results at the medial and lateral femur and medial tibia were significant. Cysts were also found in T2DM rats at the junction of the articular cartilage and subchondral bone. Immunohistochemical analysis does not show an increase in collagen II between control and T2DM rats. Mass comparisons also showed a significant relationship between mass and osteoarthritis score.

Conclusions

T2DM was found to cause global degeneration in the UCD rat knee joints, suggesting that diabetes itself is a factor in the onset and progression of osteoarthritis. The immunohistochemistry stains showed little to no change in collagen II degeneration between T2DM and control rats. Overall, it seems that the animal model used is pertinent to future studies of T2DM in the development and progression of osteoarthritis.

Cite this article: Bone Joint Res 2014;3:203–11

Co-administration of hyaluronic acid with local anaesthetics shows lower cytotoxicity than local anaesthetic treatment alone in bovine articular chondrocytes

OBJECTIVE

To study the effect of hyaluronic acid (HA) on local anaesthetic chondrotoxicity in vitro.

METHODS

Chondrocytes were harvested from bovine femoral condyle cartilage and isolated using collagenase-containing media. At 24 hours after seeding 15 000 cells per well onto a 96-well plate, chondrocytes were treated with media (DMEM/F12 + ITS), PBS, 1:1 lidocaine (2%):PBS, 1:1 bupivacaine (0.5%):PBS, 1:1 lidocaine (2%):HA, 1:1 bupivacaine (0. 5%):HA, or 1:1 HA:PBS for one hour. Following treatment, groups had conditions removed and 24-hour incubation. Cell viability was assessed using PrestoBlue and confirmed visually using fluorescence microscopy.

RESULTS

Media-treated groups had a mean of 1.55×10(4) cells/well (sem 783). All treated cells showed statistically significant reduced viability when compared with media alone (all p < 0.003). Cells treated with bupivacaine + HA (6.70×10(3) cells/well (sem 1.10×10(3))) survived significantly more than bupivacaine (2.44×10(3) cells/well (sem 830)) (p < 0.001). Lidocaine + HA (1.45×10(3) cells/well (sem 596)) was not significantly more cytotoxic than lidocaine (2.24×10(3) cells/well (sem 341)) (p = 0.999). There was no statistical difference between the chondrotoxicities of PBS (8.49×10(3) cells/well (sem 730) cells/well) and HA (4.75×10(3) cells/well (sem 886)) (p = 0.294).

CONCLUSIONS

HA co-administration reduced anaesthetic cytotoxicity with bupivacaine but not lidocaine, suggesting different mechanisms of injury between the two. Co-administered intra-articular injections of HA with bupivacaine, but not lidocaine, may protect articular chondrocytes from local anaesthetic-associated death. Cite this article: Bone Joint Res 2013;2:270-5.

18-FDG-PET in assessing disease activity in Takayasu arteritis: a meta-analysis

OBJECTIVES

To assess the diagnosis value of 18-FDG-PET in estimating disease activity in Takayasu arteritis.

METHODS

A complete search of PubMed, EMBASE and The Cochrane Library was finished to July 25, 2012. Sensitivity and specificity as well as pooled estimates of positive and negative likelihood ratios (PLR and NLR) were calculated by Meta-Disc. We also calculated the area under the sROC curve (AUC) and the Q* index.

RESULTS

The meta-analysis was finished with 6 study retrieved from the database search. The pooled sensitivity, and specificity with 95% confidence interval were 70.1% (95% CI, 58.6-80.0) and 77.2% (95% CI, 64.2-87.3). The PLR and NLR were 2.313 (95% CI 1.108-4.829) and 0.341 (95% CI 0.142-0.824). The AUC was 0.805(±0.084) and Q* index was 0.7402 (±0.0739).

CONCLUSIONS

18-FDG-PET had moderate diagnosis value in assessing TA activity. It may add additional value to the current diagnosis methods.

A phylogenetic analysis of the genus Pleurothallis, with emphasis on Pleurothallis subsection Macrophyllae-Fasciculatae, using nuclear ITS and chloroplast DNA sequencing

Several revisions of the genus Pleurothallis have been proposed. Luer has proposed that Pleurothallis species in subgenus Scopula be segregated into the genera Colombiana and Ancipitia. Szlachetko and Margonska (2001) proposed the genus Zosterophyllanthos for Pleurothallis subsection Macrophyllae-Fasciculatae. As an alternative, Luer (2005) proposed the genus Acronia by uniting Pleurothallis subsection Macrophyllae-Fasciculatae with subsections Acroniae and Amphygiae. The molecular phylogenetic studies by Pridgeon and Chase (2001), however, suggested that these taxonomic revisions might not be justified. We report here a more detailed phylogenetic analysis of the genus Pleurothallis, with emphasis on subsection Macrophyllae-Fasciculatae, with data primarily from nuclear ITS sequencing, supplemented with preliminary data from plastid DNA (rpoB2, rpoC1, and ycf1) sequencing. Some initial, tentative conclusions can be drawn. In the strict consensus maximum-parsimony tree of ITS data, many of the clades collapse, leaving a polytomy with a single, highly supported node that tentatively could be used to delimit the genus Pleurothallis. Such a tree would argue for an expanded concept of the genus Pleurothallis, in which the groups Ancipitia, Colombiana, and Acronia/Zosterophyllanthos, if shown to be monophyletic, are relegated to subgenera. 

Staphylococcal toxic shock syndrome

A 28 year old male presented with fever, tachycardia, generalized lymphadenopathy and diffuse rash over the body. He failed to respond to intravenous antibiotics and developed cardiogenic shock, multiple organ failure and died within six hours after hospitalization. Staphylococcus aureus colonies were revealed on blood culture.

Antimicrobial price variation: conundrum of medical profession!

Pharmacoeconomics plays a pivotal role in clinical practice. High medicine prices can adversely affect a patient's finances and compliance. The Indian pharmaceutical industry has become a cornucopia of medicines with wide variation in prices for the same medicine marketed under different brand names. Price list of available antimicrobial brands was procured from a commercial drug directory. Average price of widely prescribed oral antimicrobials was found and price variation between different brands was calculated. The variation in medicine prices was found to be from 95% lower to more than 350% higher than the average price. Implications of price variation in clinical practice are discussed and remedial measures suggested.

Rosai Dorfman syndrome with sinonasal mucosa and intraocular involvement

A 15 year-old-male presented with concurrent sinonasal polyposis and anterior uveitis with cervical lymph node enlargement. Cervical lymph node biopsy confirmed Rosai-Dorfman disease. Though patient's eye symptoms did not respond well to topical corticosteroid treatment but he showed a remarkable regression in the size of nasal polyps and cervical lymph nodes after systemic corticosteroids. Intraocular involvement in such a case is rare.

Effects of losartan and irbesartan on serum uric acid in hypertensive patients with hyperuricaemia in Chinese population

Therapy with losartan compared to irbesartan was performed in a Chinese sample of hypertensive patients with elevated serum uric acid (SUA) levels. After 1 week of screening and a 2 week single-blinded placebo baseline period, patients were treated for 4 weeks with losartan 50 mg or irbesartan 150 mg. After 4 weeks, patients with SiDBP <90 mmHg and SiSBP <140 mmHg continued the same dose regimen for another 4 weeks. If blood pressure was not controlled after 4 weeks of treatment, the dose of either regimen was doubled to losartan 100 mg and irbesartan 300 mg. There were 351 patients randomized (176 to losartan and 175 to irbesartan), and of these, 325 patients completed the study (162 in the losartan group and 163 in the irbesartan group). At baseline, the median SUA level in the losartan group was 422 and 420 micromol/l in the irbesartan group. At 8 weeks of therapy, SUA decreased by 63 mumol/l in the losartan group compared to 12 mumol/l in the irbesartan group (P < 0.0001). Blood pressure declined comparably in both groups from 151/92 mmHg at baseline to 137/83 and 135/83 (losartan and irbesartan, respectively, NS). No severe AEs were found for either treatment group. Therapy with losartan decreased SUA levels significantly more than irbesartan in Chinese patients with hypertension and elevated SUA levels, demonstrating the unique uricosuric effect of this ARB in this ethnic group.

Negative feedback on the effects of stem cell factor on hematopoiesis is partly mediated through neutral endopeptidase activity on substance P: a combined functional and proteomic study

Hematopoietic regulation is a complex but dynamic process regulated by intercellular and intracellular interactions within the bone marrow (BM) microenvironment. Through neurokinin-1 (NK-1) and NK-2 receptors, peptides (eg, substance P [SP]) encoded by the preprotachykinin-I gene mediate distinct hematopoietic effects. Cytokines, associated with hematopoietic stimulation, and SP regulate the expression of each other in BM mesenchymal and immune cells. Neutral endopeptidase (NEP) uses SP as a substrate to produce SP(1-4), which inhibits the proliferation of matured myeloid progenitor. This study determines whether the degradation of SP to SP(1-4) by endogenous NEP in BM stroma could be a feedback on hematopoietic stimulation by stem cell factor (SCF). SP(1-4) induced the production of transforming growth factor (TGF)-beta and tumor necrosis factor-alpha in BM stroma. TGF-beta production accounted for part of the inhibitory effects by SP(1-4) on the proliferation of early (granulocyte-macrophage colony-forming units) and late (long-term culture-initiating cells) hematopoietic progenitors. Enzyme-linked immunosorbent assays and/or protein-chip arrays indicated a timeline change of SP to SP(1-4) in BM stroma stimulated with SCF, which correlated with increase in NEP messenger RNA. Since SP and its fragment, SP(1-4), interact with the same receptor to mediate opposing hematopoietic effects, 2 interactive studies were done to understand the dual responses of NK-1: (1) a 3-dimensional molecular model of NK-1 and SP and (2) screening of a random dodecapeptide library for SP(1-4) interacting sites. The effects of SP(1-4) on hematopoietic progenitors and the timeline change of SP to SP(1-4), together with the 3-dimensional model, provide a partial explanation for the feedback on the stimulatory effects of SCF and SP on hematopoiesis.

Pannier is a transcriptional target and partner of Tinman during Drosophila cardiogenesis

During Drosophila embryogenesis, the homeobox gene tinman is expressed in the dorsal mesoderm where it functions in the specification of precursor cells of the heart, visceral, and dorsal body wall muscles. The GATA factor gene pannier is similarly expressed in the dorsal-most part of the mesoderm where it is required for the formation of the cardial cell lineage. Despite these overlapping expression and functional properties, potential genetic and molecular interactions between the two genes remain largely unexplored. Here, we show that pannier is a direct transcriptional target of Tinman in the heart-forming region. The resulting coexpression of the two factors allows them to function combinatorially in the regulation of cardiac gene expression, and a physical interaction of the proteins has been demonstrated in cultured cells. We also define functional domains of Tinman and Pannier that are required for their synergistic activation of the D-mef2 differentiation gene in vivo. Together, these results provide important insights into the genetic mechanisms controlling heart formation in the Drosophila model system.

Genetic variation in the promoter region of the beta2 bradykinin receptor gene is associated with essential hypertension in a Chinese Han population

The present study examined whether a genetic variant (-58T/C) in the promoter region of the human beta2 bradykinin receptor gene was genetically involved in essential hypertension. Chinese hypertensive subjects (n = 120) and normotensive controls (n = 98; sex- and age-matched with hypertensives) were recruited from the outpatients of Fu Wai hospital. Distribution of the -58T/C polymorphism was determined in patients and controls by means of PCR, SSCP, cloning and sequencing. The allelic frequencies were 0.56 for the C allele and 0.44 for the T allele in hypertensive subjects, and 0.46 for the C allele and 0.54 for the T allele in normotensive subjects. The allelic frequencies were in Hardy-Weinberg equilibrium. Significant differences between hypertensive and normotensive subjects were seen in the genotypes distribution (p = 0.045) and allelic frequencies (p = 0.033). These results suggested that -58C allele of the human beta2 bradykinin receptor gene may be an independent risk factor for essential hypertension in the Chinese Han population.

Plasma endothelin-1 levels and circulating endothelial cells in patients with aortoarteritis

To investigate the correlation between plasma endothelin-1 (ET-1), circulating endothelial cells (CECs), and the disease activity in patients with aortoarteritis. In this study, radioimmunoassay was used to measure plasma levels of ET-1 in 56 patients with aortoarteritis. Circulating endothelial cell counts were also carried out as an indicator of vessel wall lesions. The plasma levels of ET-1 and CECs in the active disease patient group were significantly higher than those in inactive patient group (p<0.001). A significant positive correlation was found between plasma ET-1 levels and erythrocyte sedimentation rates (ESRs) in patients with aortoarteritis (r=0.645, p<0.001), as well as CECs (r=0.876, p<0.001). These results suggested that the ET-1 secreted during the active stages of aortoarteritis may cause constriction and proliferation of vascular smooth muscle cells, thus contributing to the pathogenesis of luminal narrowing. The increased CECs might serve as a marker of disease activity.

HPK1 is activated by lymphocyte antigen receptors and negatively regulates AP-1

The serine/threonine kinase HPK1 is a member of the germinal center kinase (GCK) family that has been implicated in the regulation of MAP kinase pathways. Here, we demonstrate the involvement of HPK1 in antigen receptor signaling. Engagement of the TCR or the BCR resulted in a marked induction of HPK1 catalytic activity. Subsequent analysis revealed that Src and Syk/ZAP-70 tyrosine kinases and the adaptor proteins LAT, SLP-76, BLNK, Grb2, and Grap are involved in HPK1 activation. Overexpression of HPK1 inhibited TCR activation of AP-1 and ERK2, whereas the kinase-inactive mutant of HPK1 potentiated these responses. Neither form of HPK1 affected PMA or v-Ras activation of AP-1 and ERK2. Thus, HPK1 is a negative regulator of the TCR-induced AP-1 response pathway.

The role of the renin-angiotensin and cardiac sympathetic nervous systems in the development of hypertension and left ventricular hypertrophy in spontaneously hypertensive rats

To elucidate the relationship between the development of left ventricular hypertrophy (LVH) in hypertension and the development of both the cardiac sympathetic nervous and renin-angiotensin systems, as measured by norepinephrine and angiotensin II levels, respectively. In this longitudinal study, we compared blood pressure (BP), left ventricular weight, and norepinephrine (NE) and angiotensin II (Ang II) concentrations, in Spontaneously Hypertensive Rats (SHR) and age-matched Wistar-Kyoto (WKY) rats at 5, 10, 15, 20, and 28 wk of age. Blood pressure, plasma and ventricular Ang II and tissue NE were measured by the tail-cuff method, radioimmunoassay, and high-performance liquid chromatography (HPLC), respectively. At 5 wk, systolic blood pressure was the same in both strains. But the left ventricular plus septum weight to body weight (LVSW/BW) ratio was higher in SHR than in WKY rats (p < 0.01), which finding may have been related to the increased cardiac tissue NE concentration, and this increase tended to parallel the rise in blood pressure. Both left ventricle and forelimb muscle NE concentrations were significantly higher in SHR than in WKY rats at 5, 10, and 15 wk of age (p < 0.01, respectively), and were similar at 20 and 28 wk of age. The heart and plasma Ang II levels decreased with age, which results were in keeping with the known developmental tendencies of the biological aging progress. There was no significant difference in plasma Ang II levels between the two strains from 5 to 20 wk, whereas these levels were remarkably higher in WKY than in SHR rats at 28 wk (p< 0.01). Otherwise, the left ventricular tissue Ang II concentrations were significantly higher in SHR than in WKY rats at the late stage (from 15 to 28 wk), which may have contributed to the late-stage cardiac hypertrophy. These results suggested that the sympathetic nervous system (SNS) and the renin-angiotensin-system (RAS) in SHR may contribute to the pathogenesis of hypertension and LVH at the early and late stages, respectively.

Characterization of antihuman IFNAR-1 monoclonal antibodies: epitope localization and functional analysis

The type I interferon receptor (IFNAR) is composed of two subunits, IFNAR-1 and IFNAR-2, encoding transmembrane polypeptides. IFNAR-2 has a dominant role in ligand binding, but IFNAR-1 contributes to binding affinity and to differential ligand recognition. A panel of five monoclonal antibodies (mAb) to human IFNAR-1 (HuIFNAR-1) was produced and characterized. The reactivity of each mAb toward HuIFNAR-1 on native and transfected cells and in Western blot and ELISA formats was determined. In functional assays, one mAb, EA12, blocked IFN-a2 binding to human cells and interfered with Stat activation and antiviral activity. Epitopes for the mAb were localized to subdomains of the HuIFNAR-1 extracellular domain by differential reactivity of the mAb to a series of human/bovine IFNAR-1 chimeras. The antibody EA12 seems to require native HuIFNAR-1 for reactivity and does not map to a single subdomain, perhaps recognizing an epitope containing noncontiguous sequences in at least two subdomains. In contrast, the epitopes of the non-neutralizing mAb FB2, AA3, and GB8 mapped, respectively, to the first, second, and third subdomains of HuIFNAR-1. The mAb DB2 primarily maps to the fourth subdomain, although its reactivity may be affected by other determinants.

Mapping human interferon-alpha (IFN-alpha 2) binding determinants of the type I interferon receptor subunit IFNAR-1 with human/bovine IFNAR-1 chimeras

Type I interferons bind to a common receptor (IFNAR), composed of two transmembrane polypeptides, IFNAR-1 and IFNAR-2. Although human IFNAR-1 has a weak intrinsic affinity for human Type I interferons (IFNs), bovine IFNAR-1 binds human Type I IFNs with moderate (nM) affinity, and can be conveniently used to investigate the regions of IFNAR-1 involved in ligand binding. We have constructed 14 bovine/human IFNAR-1 chimeras by exchanging homologous subdomains in the extracellular portion of the receptor. These chimeras were expressed at very high levels on COS cells, and their ability to bind HuIFN-alpha2 was measured. No single bovine subdomain substituted into human IFNAR-1 could confer moderate-affinity ligand binding on the resulting chimera. Simultaneous substitution of bovine IFNAR-1 subdomains 2 and 3 for the homologous human subdomains resulted in a dramatic increase in the binding of IFN-alpha2, suggesting that critical determinants for moderate-affinity ligand binding by BoIFNAR-1 reside in these two subdomains. Bovine subdomains 1 and/or 4 each further enhanced IFN-alpha2 binding in the presence of bovine subdomains 2 and 3. Thus, the binding interactions of BoIFNAR-1 with IFNs appears to be more complex than that of other class II cytokine receptors with their ligands.

The MEK1 proline-rich insert is required for efficient activation of the mitogen-activated protein kinases ERK1 and ERK2 in mammalian cells

MEK1 and MEK2 contain a proline-rich insert not present in any other known MEK (MAP (mitogen-activated protein)/ERK (extracellular signal-regulated kinase) kinase) family members. We examined the effect of removing the MEK1 polyproline insert on MEK activity, its binding to Raf, and its ability to activate ERKs in cells. Deletion of the insert had no effect on either the activity of MEK1 or on its ability to bind to Raf-1. Both wild type and constitutively active MEK1 coimmunoprecipitated with Raf-1 whether or not the insert was present. Deletion of the insert did not reduce activation of MEK1 by EGF or activated Raf in cells. The proline-rich insert enhanced the ability of an otherwise equally active MEK1 protein to regulate endogenous ERKs in mammalian cells. Overexpression of either constitutively active MEK1 lacking the insert or ERK2 compensates for the weaker in vivo activity of the MEK1 deletion mutant. Expression of the insert in cells reduced activation of ERKs by EGF. We conclude that the proline-rich insert is not the site of the MEK-Raf interaction and that the polyproline insert is required for its efficient activation of downstream ERKs in cells.

Differential regulation of mitogen-activated protein/ERK kinase (MEK)1 and MEK2 and activation by a Ras-independent mechanism

Mitogen-activated protein (MAP)/ERK kinase (MEK)1 and MEK2 are the upstream activators of the MAP kinases, ERK1 and ERK2. MEK1 and MEK2 are approximately 85% identical in sequence but have unique inserts in their C-terminal domains. MEK isoform-specific antibodies were used to examine expression and regulation of each enzyme. MEK1 and MEK2 were expressed in approximately equal amounts in several cell lines; in some, MEK1 was present in slight excess. Activation of tyrosine kinase-containing receptors, heterotrimeric G proteins, and protein kinase C enhanced the activities of both MEK isoforms in 293 and PC12 cells. AIF4-stimulated both MEK1 and MEK2 in PC12 cells expressing a dominant interfering Ras mutant that prevents nerve growth factor-dependent activation of the cascade. Carbachol also stimulated the pathway in these cells. Thus, in addition to their ability to activate Ras/Raf and the downstream ERK pathway, heterotrimeric G proteins also appear to trigger a Ras-independent mechanism to regulate this kinase cascade. In U373, Chinese hamster ovary (CHO), and INS-1 cells, MEK1 was activated by regulators of ERKs, while MEK2 was not. These data suggest that, like the MAP kinases ERK1 and ERK2, in some cell settings the two similar MEK isoforms are differentially regulated.

Glutamine suppresses PGE2 synthesis and breast cancer growth

Reduced natural killer (NK) activity found in tumor-bearing hosts has been associated with high levels of prostaglandin E2 (PGE2) produced by monocytes in vitro. We have previously demonstrated a dependence of NK cell activity on glutamine (GLN) levels in vitro and in vivo. Further, glutathione (GSH) is antagonistic to PGE2 synthesis. We hypothesized that GLN, through increased GSH production, leads to decreased PGE2 synthesis and upregulation of NK cytotoxic activity. To test this, we examined the effects of oral GLN on GSH and PGE2 concentrations, NK activity and tumor growth in a rat breast cancer model. Starting on the day of MTF-7 tumor implantation 18 Fisher 344 rats were pair-fed chow and gavaged with 1 g/kg/day GLN (n = 9) or an isonitrogenous amount of Freamine (FA) (n = 9). Seven weeks after tumor implantation rats were sacrificed. Tumors were measured, weighed, and processed for tumor morphometrics. Spleens were removed, lymphocytes isolated and assayed for NK activity. Blood GLN, GSH, and PGE2 concentrations were measured. Over the 7-week study period tumor growth was decreased by approximately 40% in the GLN-supplemented group. This decrease in growth was associated with a 2.5 fold greater NK activity in the GLN-fed rats vs FA-fed rats. This correlated with a 25% rise in GSH concentration and a proportional decrease in PGE2 synthesis. Decreased tumor volume in rats fed GLN was not associated with changes in morphometrics. Oral GLN supplementation enhances NK activity resulting in decreased tumor growth. The enhanced NK activity seen with oral GLN supplementation in the tumor-bearing host is associated with GSH mediated suppression of PGE2 synthesis.

MEKK1 phosphorylates MEK1 and MEK2 but does not cause activation of mitogen-activated protein kinase

A constitutively active fragment of rat MEK kinase 1 (MEKK1) consisting of only its catalytic domain (MEKK-C) expressed in bacteria quantitatively activates recombinant mitogen-activated protein (MAP) kinase/extracellular signal-regulated protein kinase (ERK) kinases 1 and 2 (MEK1 and MEK2) in vitro. Activation of MEK1 by MEKK-C is accompanied by phosphorylation of S218 and S222, which are also phosphorylated by the protein kinases c-Mos and Raf-1. MEKK1 has been implicated in regulation of a parallel but distinct cascade that leads to phosphorylation of N-terminal sites on c-Jun; thus, its role in the MAP kinase pathway has been questioned. However, in addition to its capacity to phosphorylate MEK1 in vitro, MEKK-C interacts with MEK1 in the two-hybrid system, and expression of mouse MEKK1 or MEKK-C in mammalian cells causes constitutive activation of both MEK1 and MEK2. Neither cotransfected nor endogenous ERK2 is highly activated by MEKK1 compared to its stimulation by epidermal growth factor in spite of significant activation of endogenous MEK. Thus, other as yet undefined mechanisms may be involved in determining information flow through the MAP kinase and related pathways.

Regulation and properties of extracellular signal-regulated protein kinases 1, 2, and 3

The extracellular signal-regulated kinases ERK1 and ERK2 are 43- and 41-kd enzymes activated by many extracellular cues. They lie within a protein kinase cascade that is used to achieve many cellular responses. In addition to the wide variety of regulatory contexts in which they are activated, they phosphorylate important regulatory proteins, including receptors, transcription factors, cytoskeletal proteins, and other protein kinases. Thus, the stimulation of this kinase cascade is thought to have a pleiotropic action. ERK1 and ERK2 are controlled by phosphorylation on threonine and tyrosine. To understand the regulatory mechanisms, wild-type and mutant ERKs were expressed in bacteria and phosphorylated with MEK, the enzyme that is upstream of ERKs. Wild-type proteins could be activated 500- to 1,000-fold in vitro by MEK. ERK3, an enzyme of 62 kd and only 50% identical to ERK1 and ERK2 in the catalytic core, was also phosphorylated by MEK in vitro. This suggests that all three of these enzymes are targets of common signaling pathways.

Regulatory aspects of clonally expanded B-1 (CD5+ B) cells

B-1 (CD5+ B) cells appear early in ontogeny, produce mainly unmutated polyreactive antibodies, and are capable of self-renewal. B-1 cells clonally expand with age and are the malignant cell in chronic lymphocytic leukemia. In this report immunological analysis of B-1 malignancies in NZB mice, a murine model of chronic lymphocytic leukemia, is related to current information on B-1 cells. B-1 clones from NZB mice produce high levels of interleukin-10, detected at the RNA level by semi-quantitative polymerase chain reaction. In addition, the B-1 malignant clones in NZB mice and their hybrids, are negative for B220/6B2 expression, the B-specific antigenic form of CD45 which is a membrane-associated phosphatase involved in lymphocyte activation. Both the autocrine production by B-1 cells of interleukin-10 and altered CD45 expression may be responsible for the clonal expansion of these cells, as well as the accompanying T cell expansion. We report the establishment of an in vitro cytotoxic CD8+ T cell line derived from an NZB with a B-1 malignancy. The effect of B-1 cell-derived interleukin-10 on subsets of T lymphocytes may account for the immunoregulatory properties of B-1 cells. In addition, the NZB malignancies were also characterized for immunoglobulin variable region sequence and antigen specificity. The B-1 malignancies produced immunoglobulin derived from unmutated germline sequences with no N base substitutions. It appears that both the immunoglobulin and interleukin-10 produced by the B-1 malignant cell in NZB mice may have immunoregulatory properties. A study of B-1 malignancies may shed light on the immunoregulatory properties of non-clonally expanded normal B-1 cells.

Induction of a protective immune response in rats by injection of live or killed S. mansoni worms

Resistance to S. mansoni cercarial challenge, induced by prior infection of rats with cercariae, is analysed by substitution of alternatives to the primary cercarial exposure. Intravenous injections of either live or killed 4-week stage worms have been examined, utilizing two different routes of injection, one or two injected doses, and two different methods to kill worms. In addition to assessing peripheral blood eosinophil levels, anti-schistosome antibody titres, and challenge worm burdens in the injected and control recipients, sera from these rat groups collected 3 weeks after challenge were used for passive immunization studies in rats. Recipients of intravenous live worm injections were resistant to a cercarial challenge and yielded sera capable of passively immunizing rats. Recipients of intravenous killed worm injections were not significantly resistant to a challenge infection, yet paradoxically, yielded sera capable of passively immunizing rats. Serum from challenge control rats was not significantly protective in the passive immunization assay. There were no correlations between peripheral blood eosinophil levels or anti-schistosome antibody titres and resistance (either active or passive). We conclude that killed worms induce an immune response which, although insufficient to provide protection by itself, can be recalled or augmented by a challenge infection to result in significant levels of serum protective activity.

Inhibiton of prostaglandin synthesis by human amniotic fluid: acute reduction in inhibitory activity of amniotic fluid obtained during labor

Human amniotic fluid contains an inhibitor of prostaglandin synthesis. The activity of the inhibitor was measured in amniotic fluid obtained in early pregnancy, and at term both before and after the onset of labor. The inhibitory activity was greater in amniotic fluid taken in early pregnancy than in fluid taken at term before the onset of labor (P less than 0.05). There was a further significant reduction in inhibitory activity (P less than 0.01) in amniotic fluid collected during labor. These results are suggestive that the onset of labor is associated with a local withdrawal of inhibition of prostaglandin biosynthesis.