Anti-Inflammatory Klotho Protein Serum Concentration Correlates with Interferon Gamma Expression Related to the Cellular Activity of Both NKT-like and T Cells in the Process of Human Aging

Klotho is a beta-glucuronidase that reveals both anti-inflammatory and anti-oxidative properties that have been associated with mechanisms of aging. The study aimed to analyze the relationships between the serum concentration of soluble α-Klotho and cellular activity of two populations of lymphocytes; T and NKT-like cells corresponding to the level of cytokine secretion; i.e., IFN-γ, TNF-α, and IL-6. The studied population comprised three age groups: young individuals ('young'), seniors aged under 85 ('old'), and seniors aged over 85 ('oldest'). Both NKT-like and T cells were either non-cultured or cultured for 48 h and stimulated appropriately with IL-2, LPS or PMA with ionomycin to compare with unstimulated control cells. In all studied age groups non-cultured or cultured NKT-like cells revealed higher expressions of TNF-α, IL-6, and IFN-γ than T cells. α-Klotho concentration in serum decreased significantly in the process of aging. Intriguingly, only IFN-γ expression revealed a positive correlation with α-Klotho protein serum concentration in both non-cultured and cultured T and NKT-like cells. Since IFN-γ is engaged in the maintenance of immune homeostasis, the observed relationships may indicate the involvement of α-Klotho and cellular IFN-γ expression in the network of adaptive mechanisms developed during the process of human aging.

NKT-like (CD3 + CD56+) cells differ from T cells in expression level of cellular protective proteins and sensitivity to stimulation in the process of ageing

BACKGROUND

NKT-like cells are T lymphocytes coexpressing several NK cell-associated receptors. They are effector lymphocytes of innate and adaptive immunity, and their number increases with age. The study aimed to analyze the expression of cellular protective proteins, i.e. sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in NKT-like and T cells of the young ('young', 31 subjects, age range 19-24 years), seniors aged under 85 ('old'; 30 subjects, age range 65-84 years) and seniors aged over 85 ('oldest', 24 subjects, age range 85-94 years). Both NKT-like and T cells were cultured for 48 h and stimulated with IL-2, LPS and PMA with ionomycin and compared with unstimulated control cells.

RESULTS

The oldest seniors varied from the other age groups by significantly increased expression of SIRT1 and HSP70 in both NKT-like and T cells observed in both stimulated and nonstimulated cells. The analyzed lymphocyte populations of the oldest revealed not only the highest expression of these proteins but also insensitivity to all types of applied stimulation. When NKT-like cells were compared to T cells, higher expression of the studied protective proteins was observed in both stimulated and unstimulated NKT-like cells. Neither CD3 + CD56+ nor CD3+ cells revealed elevated expression of SOD2, and these cells responded to stimulation until very advanced age. T cells revealed higher sensitivity to stimulation with IL-2 regarding SIRT1 and HSP70 expression. NKT-like cells were more sensitive to stimulation with PMA and ionomycin concerning the expression of these proteins. IL-2 did not induce a significant increase in SOD2 expression in the studied age groups.

CONCLUSIONS

The oldest seniors developed an adaptive stress response in both T and NKT-like cells regarding the expression of SIRT1 and HSP70, which was increased and insensitive to further stimulation in contrast to SOD2, which showed a more inducible pattern of expression. CD3 + CD56+ cells exhibited higher expression of cellular protective proteins than CD3+ cells in both stimulated and control, nonstimulated cells. NKT-like and T cells showed a distinct sensitivity to the applied stimulatory factors in the respective age groups.

Muscle pain and muscle weakness in COVID19 patients: Cross-talk with statins - Preliminary results

Background

Muscle pain and muscle weakness, common symptoms among statin-treated patients, may worsen with COVID-19 infection.

Aims

The aim of the paper was to find out if concomitant COVID-19 infections increase the frequency of specific side effects of statins such as muscle pain and muscle weakness.

Method

A total of 66 patients diagnosed with COVID-19 without comorbidities participated in the study. The patients were divided into two groups: statin-users who had not experienced adverse effects of statins in the past (statin group (SG)) and patients who had not used any drugs in the past six months (control group (CG)). The severity of muscle pain and creatinine kinase (CK) activity was evaluated in each patient, and muscle weakness was confirmed by a dynamometer test (grip strength on both hands).

Results

In SG, muscle pain was more common and it was characterized by a high level of intensity. Muscle weakness occurred more frequently in the SG and it was more frequent compared to CG. The CK parameter was observed to be higher in the SG compared to the CG and was often associated with the severity of muscle pain in the range of moderate to severe.

Conclusions

Our study indicates that COVID-19 is associated with the higher risk of occurrence of typical statin-related side effects, especially with more advanced age, which should be considered in future trials and treatments.

Narrowband ultraviolet B phototherapy is associated with a reduction in topical corticosteroid and clinical improvement in atopic dermatitis: a historical inception cohort study

BACKGROUND

Despite decades of use, the magnitude of efficacy of narrowband ultraviolet B (NB-UVB) phototherapy for atopic dermatitis (AD) beyond industry-sponsored trials remains unclear.

AIM

To evaluate the clinical efficacy of NB-UVB in AD under real-world conditions.

METHODS

We conducted a historical inception cohort study using automated recording of dispensed drugs to provide an objective treatment outcome in a large population catchment of 420 000 people over 15 years. We analysed clinical treatment outcomes, recorded multicentre and prospectively over 15 years, of a large AD treatment cohort (n = 844), along with the drugs dispensed to this cohort.

RESULTS

The majority (70%) of patients with AD received significantly fewer topical corticosteroids (TCS) during the 12-month window after finishing NB-UVB compared with the 12-month window before starting the treatment (median reduction from 37.5 to 19.7 g/month). The number of patients dispensed with oral corticosteroids and antihistamines also dropped significantly (from 20% to 10% and from 69% to 31%, respectively), while all AD-unrelated drugs dispensed remained unchanged. Clinically, NB-UVB treatment achieved a 'clear' or 'almost clear' status in 48.7% of patients, while 20.4% achieved 'moderate clearance'. Treatment outcomes scores were validated by a strong correlation with reduction in AD-specific drug treatment.

CONCLUSION

Our data confirm the significant efficacy of NB-UVB for AD under conditions of routine care.

Quantitative analysis of topical treatments in atopic dermatitis: unexpectedly low use of emollients and strong correlation of topical corticosteroid use both with depression and concurrent asthma

BACKGROUND

Despite decades of use, the actual amounts of topical corticosteroids (TCS) and emollients used in moderate-to-severe atopic dermatitis (AD) under real-world conditions are unknown. Thus, it remains unclear whether inadequate use is widespread.

OBJECTIVES

To quantify the use of TCS and emollients in moderate-to-severe AD.

METHODS

Double-blinded drug prescribing was recorded prospectively at the point of drug dispensing within a catchment area of approximately 450 000 people over a 31-year period in a population-based cohort marked by failure of disease control in primary care (n = 844). For each patient, prescribing was recorded over a 12-month period in order to minimize fluctuations.

RESULTS

This approach resulted in a near-complete dataset, which was essentially free of reporting bias and recording bias. Atopic comorbidities matched expected frequencies. Median use of TCS was statistically significantly higher in juvenile patients (age < 16 years) compared with adult patients (49·2 vs. 38·1 g per month), in male vs. female patients (46·8 vs. 29·7 g per month) and in patients receiving concurrent asthma treatment (40·4 vs. 26·7 g per month). TCS use was strongly associated with antidepressant treatment. Emollient use was unexpectedly low with a median of 9·6 g per day (range 1·4-30·1). Results were replicated in an independent validation cohort.

CONCLUSIONS

Deficient use of emollients may be a factor contributing to AD severity. Our analysis showed that the use of TCS does not exceed current guidelines. Accurate quantification of topical treatments provides a widely accessible strategy to measure the real-world impact of novel AD treatments. What's already known about this topic? Both emollient and topical corticosteroid (TCS) use have been a mainstay of atopic dermatitis (AD) treatment for over 60 years. The actual quantities used by patients under real-world conditions are unknown. What does this study add? The real-world use of emollients is fourfold lower than the amount recommended in current guidelines. Underuse of emollients may be a significant factor in disease exacerbation. The use of TCS is significantly higher in male patients and is higher in patients with AD who also have asthma. The use of TCS is strongly associated with concurrent antidepressant treatment.

NKT-like cells reveal higher than T lymphocytes expression of cellular protective proteins HSP70 and SOD2 and comparably increased expression of SIRT1 in the oldest seniors

INTRODUCTION

NKT-like cells are "non-classical", "CD1d-independent" NKT cells which represent highly differentiated, conventional T lymphocytes coexpressing several NK (natural killer) associated receptors. They are effector lymphocytes of both innate and adaptive immunity and simultaneously regulatory cells of the adaptive immune system. They reveal large granular lymphocyte morphology and can mediate both MHC-restricted and MHC-unrestricted cytotoxicity, secrete many cytokines and modulate Th1 immune responses. The aim of our study was to analyze the expression of proteins involved in cellular stress response: sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in NKT-like cells compared to T lymphocytes during ageing.

MATERIAL AND METHODS

The study involved three groups of participants: the oldest seniors (n = 25; aged over 85; mean age 88 ± 0.5 ys), the old (n = 30; aged under 85; mean age 76 ± 0.9 ys) and the young (n = 32; mean age 21 ± 0.3 ys). Whole blood samples were analyzed by flow cytometry to assess the NKT-like (CD3+CD56+) and T (CD3+) cell populations.

RESULTS

The group of the oldest seniors differed from the other age groups by much higher percentage of both NKT-like cells and T lymphocytes expressing SIRT1, HSP70 and SOD2. The expression of these proteins correlated positively with the age of the participants. Interestingly, the significantly higher expression of the studied protective proteins; i.e. HSP70 and SOD2 was found in CD3+CD56+ cells compared to CD3+ lymphocytes and this phenomenon concerned all the studied age groups. These differences were not significant regarding the expression of SIRT1; however, the same tendency was noticeable.

CONCLUSIONS

The analysis of CD3+ and CD3+CD56+ lymphocytes showed the increase in the number of NKT-like cells and decreased number of T cells in the process of ageing. The increased expression of cellular protective proteins SIRT1, HSP70 and SOD2 in NKT-like and T-lymphocytes of the oldest seniors seems to correspond to longevity and the observed correlations may suggest the involvement of these proteins in establishing cellular homeostasis specific for healthy ageing. Furthermore, the higher expression of the protective proteins in NKT-like cells compared to T lymphocytes may indicate their particular role in the interplay between innate and adaptive immunity responses during the process of ageing.

CD56bright cells respond to stimulation until very advanced age revealing increased expression of cellular protective proteins SIRT1, HSP70 and SOD2

BACKGROUND

NK cells are cytotoxic lymphocytes of innate immunity composed of: cytotoxic CD56dim and immunoregulatory CD56bright cells. The study aimed to analyze the expression of cellular protective proteins: sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in CD56dim and CD56bright NK cells of the young, seniors aged under 85 ('the old') and seniors aged over 85 ('the oldest'). We studied both non-stimulated NK cells and cells stimulated by IL-2, LPS or PMA with ionomycin. The expression level of proinflammatory cytokines TNF and IFN-γ was also assessed in NK cell subsets and some relationships between the studied parameters were analyzed.

RESULTS

CD56bright cells showed sensitivity to most of the applied stimulatory agents until very advanced age in regards to the expression of SIRT1 and intracellular HSP70. On the contrary, CD56dim cells, sensitive to stimulation by most of the stimulatory agents in the young and the old, in the oldest lost this sensitivity and presented rather high, constant expression of SIRT1 and HSP70, resistant to further stimulation. With reference to SOD2 expression, CD56dim cells were insensitive to stimulation in the young, but their sensitivity increased with ageing. CD56bright cells were sensitive to most of the applied agents in the young and the old but in the oldest they responded to all of the stimulatory agents used in the study. Similarly, both NK cell subsets were sensitive to stimulation until very advanced age in regards to the expression of TNF and IFN-γ.

CONCLUSIONS

CD56bright cells maintained sensitivity to stimulation until very advanced age presenting also an increased expression of SIRT1 and HSP70. CD56dim cells showed a constantly increased expression of these cellular protective proteins in the oldest, insensitive for further stimulation. The oldest, however, did not reveal an increased level of SOD2 expression, but it was significantly elevated in both NK cell subsets after stimulation.The pattern of expression of the studied cellular protective proteins in ageing process revealed the adaptation of NK cells to stress response in the oldest seniors which might accompany the immunosenescence and contribute to the long lifespan of this group of the elderly.

Narrowband ultraviolet B treatment for psoriasis is highly economical and causes significant savings in cost for topical treatments

BACKGROUND

Narrowband ultraviolet B (NB-UVB) treatment for psoriasis is considered expensive. However, existing data are based on estimates and do not consider indirect cost savings.

OBJECTIVES

To define the actual costs of NB-UVB incurred by the service provider, as well as treatment-associated cost savings.

METHODS

We performed data linkage of (i) comprehensive treatment records and (ii) prescribing data for all NB-UVB treatment episodes spanning 6 years in a population of 420 000. We minimized data fluctuation by compiling data from four independent treatment sites, and using drug prescriptions unrelated to psoriasis as a negative control.

RESULTS

National Health Service Tayside spent an average of £257 per NB-UVB treatment course (mean 257 ± 63, range 150-286, across four independent treatment sites), contrasting sharply with the estimate of £1882 used by the U.K. National Institute for Health and Care Excellence. The cost of topical treatments averaged £128 per patient in the 12 months prior to NB-UVB, accounting for 42% of the overall drug costs incurred by these patients. This was reduced by 40% to £53 per patient over the 12-month period following NB-UVB treatment, while psoriasis-unrelated drug prescription remained unchanged, suggesting disease-specific effects of NB-UVB. The data were not due to site-specific factors, as confirmed by highly similar results observed between treatment sites operated by distinct staff. Finally, we detail all staff hours directly and indirectly involved in treatment, allowing direct translation of cost into other healthcare systems.

CONCLUSIONS

NB-UVB is a low-cost treatment; cost figures currently used in health technology appraisals are an overestimate based on the data presented here. Creating or extending access to NB-UVB is likely to offer additional savings by delaying or avoiding costly third-line treatments for many patients.

The Coagulation Defect in Hypervitaminosis A in Rats

Rats fed vitamin A, 70 000 u daily for a period of 28 days developed a hemorrhagic state characterized by a prolonged prothrombin time and stypven time, a marked reduction in prothrombin and the factor VII-complex, and an inconstant decrease in factor V activity. A serum defect in thromboplastin generation was also noted. The defects in the extrinsic system were prevented by the simultaneous daily feeding of 60 μg to 120 μg of vitamin K1 but this did not uniformly prevent the serum defect in thromboplastin generation which is thought to represent a depletion in factor IX.

NK cells of the oldest seniors represent constant and resistant to stimulation high expression of cellular protective proteins SIRT1 and HSP70

Background

Natural killer cells (NK cells) are cytotoxic lymphocytes of innate immunity that reveal some immunoregulatory properties, however, their role in the process of ageing is not completely understood. The study aimed to analyze the expression of proteins involved in cellular stress response: sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in human NK cells with reference to the process of ageing. Non-stimulated and stimulated with IL-2, LPS or PMA with ionomycin cells originated from peripheral blood samples of: seniors aged over 85 (‘the oldest’; n = 25; 88.5 ± 0.5 years, mean ± SEM), seniors aged under 85 (‘the old’; n = 30; 75.6 ± 0.9 years) and the young (n = 31; 20.9 ± 0.3 years). The relationships between the levels of expression of cellular protective proteins in the studied population were also analyzed. The concentrations of carbonyl groups and 8-isoprostanes, markers of oxidative stress, in both stimulated and non-stimulated cultured NK cells were measured to assess the level of the oxidative stress in the cells.

Results

The oldest seniors varied from the other age groups by significantly higher expression of SIRT1 and HSP70 both in non-stimulated and stimulated NK cells. These cells also appeared to be resistant to further stimulations with IL-2, LPS or PMA with ionomycin. Highly positive correlations between SIRT1 and intracellular HSP70 in both stimulated and non-stimulated NK cells were observed. SOD2 presented low expression in non-stimulated cells, whereas its sensitivity to stimulation increased with age of donors. High positive correlations between SOD2 and surface HSP70 were observed. We found that the markers of oxidative stress in NK cells did not change with ageing.

Conclusions

The oldest seniors revealed well developed adaptive stress response in NK cells with increased, constant levels of SIRT1 and intracellular HSP70. They presented also very high positive correlations between expression of these cellular protective proteins both in stimulated and non-stimulated cells. These phenomena may contribute to the long lifespan of this group of elderly. Interestingly, in NK cells SOD2 revealed a distinct role in cellular stress response since it showed sensitivity to stimulation increasing with age of participants. These observations provide novel data concerning the role of NK cells in the process of ageing.

Roles of calpain-calpastatin system (CCS) in human T cell activation

The immune response is determined by the speed of the T cell reaction to antigens assured by a state of readiness for proliferation and cytokine secretion. Proliferation, apoptosis and motion of many cell types are controlled by cytoplasmic proteases - μ- and m-calpain - and their inhibitor calpastatin, together forming the “calpain-calpastatin system” (CCS), assumed to modify their targets only upon activation-dependent cytoplasmic Ca²⁺ increase. Contrastingly to this notion, using quantitative real time PCR and semiquantitative flow cytometry respectively, we show here that the CCS genes are constitutively expressed, and that both calpains are constitutively active in resting, circulating human CD4⁺ and CD8⁺ lymphocytes. Furthermore, we demonstrate that calpain inhibition in the resting T cells prevents them from proliferation in vitro and greatly reduces secretion of multiple cytokines. The mechanistic reason for these effects of calpain inhibition on T cell functions might be the demonstrated significant reduction of the expression of active (phosphorylated) upstream signalling molecules, including the phospholipase C gamma, p56Lck and NFκB, in the inhibitor-treated cells. Thus, we propose that the constitutive, self-regulatory calpain-calpastatin system activity in resting human T cells is a necessary, controlling element of their readiness for complex and effective response to antigenic challenge.

Expression of cellular protective proteins SIRT1, HSP70 and SOD2 correlates with age and is significantly higher in NK cells of the oldest seniors

Background

NK cells are key effector lymphocytes of innate immunity provided with constitutive cytolytic activity, however, their role in human ageing is not entirely understood. The study aimed to analyze the expression of proteins involved in cellular stress response sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in non-stimulated NK cells of the oldest seniors (n = 25; aged over 85; mean age 88 years) and compare with NK cells of the old (n = 30; aged under 85; mean age 76 years) and the young (n = 32; mean age 21 years) to find potential relationships between the level of expression of these proteins in NK cells and longevity. The concentration of carbonyl groups and 8-isoprostanes in NK cell lysates reflecting the level of oxidative stress was also measured.

Results

The group of the oldest seniors differed from the other age groups by significantly higher percentage of NK cells expressing SIRT1, HSP70 and SOD2. The concentration of both carbonyl groups and 8-isoprostanes in NK cell extracts remained within the normal range in all age groups. The percentage of NK cells with the expression of, respectively, SIRT1, HSP70 and SOD2 correlated positively with age. Some correlations between expression levels of particular protective proteins SIRT1, HSP70 and SOD2 were observed in the study population.

Conclusions

The increased expression of cellular protective proteins SIRT1, HSP70 and SOD2 in NK cells of the oldest seniors seems to correspond to longevity and the observed correlations may suggest the involvement of these proteins in establishing NK cell homeostasis specific for healthy ageing process.

Optimal reference genes for qPCR in resting and activated human NK cells--Flow cytometric data correspond to qPCR gene expression analysis

Natural killer cells (NK cells) are cytotoxic lymphocytes critical to the innate immune system engaged in rapid response against tumor or virus infected cells. After activation NK cells acquire enhanced cytotoxicity and are capable of producing cytokines to stimulate other immune cells. Quantitative PCR (qPCR) is a method of choice for gene expression analysis but the usage of reliable reference genes for the normalization process is critical. Commonly used reference genes may vary in expression level between different experimental conditions providing wrong quantitative results of the studied genes' expression levels. Fourteen potential endogenous control genes were analyzed by qPCR method in NK-92 cell line that shows characteristics of human natural killer cells and is often used in studies on biology of NK lymphocytes. NK-92 cells were stimulated with IL-2 or TNF for 2, 24 or 72 h. Results were analyzed with RefFinder, a program which enables evaluation and screening of reference genes and integrates the currently available major computational programs (Genorm, Normfinder, BestKeeper and Delta Ct). The most stable gene in activated and non-activated NK cells was B2M, followed by IPO-8 and GAPDH and the least stable were HPRT1, PPIA and RPL32. The normalization process was performed on SOD2 gene and the results of qPCR experiments were confirmed by flow cytometry. The flow cytometric data corresponded to the results of qPCR gene expression analysis performed for the reference genes qualified by RefFinder as the most stable.

[Drug interaction in 63-year-old male sportsman--a case report]

We present a case of 63-year-old male with hypertension and hyperlipidaemia, who was an athlete in the "masters category". Because of interaction between amlodipine and simvastatin, in combination with physical activity, the patient reported: muscle pain, weakness of the muscles, dizziness, and confusion. After amlodipine and simvastatin discontinuation, all symptoms resolved rapidly.

CONCLUSIONS

(1) Concomitant use of several drugs by elderly individual patients, the risk of drug--physical activity interactions may occur.

Expression of calpain-calpastatin system (CCS) member proteins in human lymphocytes of young and elderly individuals; pilot baseline data for the CALPACENT project

BACKGROUND

Ubiquitous system of regulatory, calcium-dependent, cytoplasmic proteases - calpains - and their endogenous inhibitor - calpastatin - is implicated in the proteolytic regulation of activation, proliferation, and apoptosis of many cell types. However, it has not been thoroughly studied in resting and activated human lymphocytes yet, especially in relation to the subjects' ageing process. The CALPACENT project is an international (Polish-Italian) project aiming at verifying the hypothesis of the role of calpains in the function of peripheral blood immune cells of Polish (Pomeranian) and Italian (Sicilian) centenarians, apparently relatively preserved in comparison to the general elderly population. In this preliminary report we aimed at establishing and comparing the baseline levels of expression of μ- and m-calpain and calpastatin in various, phenotypically defined, populations of human peripheral blood lymphocytes for healthy elderly Sicilians and Poles, as compared to these values observed in young cohort.

RESULTS

We have found significant differences in the expression of both μ- and m-calpain as well as calpastatin between various populations of peripheral blood lymphocytes (CD4+, CD8+ and CD19+), both between the age groups compared and within them. Interestingly, significantly higher amounts of μ- and m-calpains but not of calpastatin could be demonstrated in the CD4+CD28- and CD8+CD28- lymphocytes of old subjects (but not in the cells of young individuals), as compared to their CD28+ counterparts. Finally, decreased expression of both calpains in the elderly T cells is not related to the accumulation of effector/memory (CD45RO+) cells in the latter, as the expression of both calpains does not differ significantly between the naïve and memory T cells, while is significantly lower for elderly lymphocytes if both populations are taken separately.

CONCLUSIONS

Observed differences in the amounts of CCS member proteins between various populations of lymphocytes of young and elderly subjects may participate in the impaired proliferative activity of these cells in the elderly.

Wnt5a inhibits the CpG oligodeoxynucleotide-triggered activation of human plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) fulfil multiple roles in immunity, and can secrete large amounts of interferon (IFN)-α. However, the available evidence suggests that they may actually counteract efficient antitumour immunity. Thus in melanoma, pDCs are abundant, but they are anergic and deficient in IFN-α secretion. pDC anergy is thought to be caused by immunosuppressive factors secreted by melanoma cells. One factor strongly expressed by melanoma is Wnt5a, which is implicated in cancer tissue invasion. In this paper, we show that Wnt5a is able to block the upregulation of the activation markers CD80 and CD86 on naive human pDCs stimulated by CpG oligodeoxynucleotide, and CpG-triggered secretion of IFN-α by pDCs. Our results suggest that Wnt5a may not only initiate cancer invasion, but could also regulate activation of pDC. These data provide a clear rationale to investigate a role for Wnt5a in immune regulation.

Integrative mRNA profiling comparing cultured primary cells with clinical samples reveals PLK1 and C20orf20 as therapeutic targets in cutaneous squamous cell carcinoma

Identifying therapeutic targets for cancer treatment relies on consistent changes within particular types or sub-types of malignancy. The ability to define either consistent changes or sub-types of malignancy is often masked by tumor heterogeneity. To elucidate therapeutic targets in cutaneous squamous cell carcinoma (cSCC), the most frequent skin neoplasm with malignant potential, we have developed an integrated approach to gene expression profiling beginning with primary keratinocytes in culture. Candidate drivers of cSCC development were derived by first defining a set of in vitro cancer genes and then comparing their expression in a range of clinical data sets containing normal skin, cSCC and the benign hyper-proliferative condition psoriasis. A small interfering RNA (siRNA) screen of the resulting 21 upregulated genes has yielded targets capable of reducing xenograft tumor volume in vivo. Small-molecule inhibitors for one target, Polo-like kinase-1 (PLK1), are already in clinical trials for other malignancies, and our data show efficacy in cSCC. Another target, C20orf20, is identified as being overexpressed in cSCC, and siRNA-mediated knockdown induces apoptosis in vitro and reduces tumor growth in vivo. Thus, our approach has shown established and uncharacterized drivers of tumorigenesis with potent efficacy as therapeutic targets for the treatment of cSCC.

Proteinuria with fumaric acid ester treatment for psoriasis

Fumaric acid esters (FAE) have been used in the treatment of psoriasis for many years. In general, they are regarded as relatively safe compared with other antipsoriatic systemic treatments, with the most notable adverse effects being gastrointestinal upset, lymphopenia and transient flushing. Renal toxicity has only rarely been reported, and was not found in two independent prospective trials nor in a large retrospective evaluation of almost 1000 patients treated for a median of 44 months. We report three patients developing reversible proteinuria during FAE treatment. One of these displayed the same pattern upon repeated drug administration, thereby clearly indicating FAE treatment to be the causal trigger. The presented cases highlight proteinuria as a clinical concern in FAE treatment. Furthermore, as the novel FAE agent dimethylfumaric (DMF) ester (contained in BG00012/Panaclar) has previously been shown to be effective in psoriasis in a phase III trial and not shown renal toxicity in a large trial for multiple sclerosis, the current report suggests that market introduction of DMF for psoriasis should be pursued.

[Chloroquine/hydroxychloroquine: variability of retinotoxic cumulative doses]

OBJECTIVE

The critical dose of chloroquine/hydroxychloroquine leading to a maculopathy or generalised retinopathy remains undetermined. In the literature, 100 g is considered the dose at which regular vision checks should be performed. Generally, chloroquine is said to be more toxic than hydroxychloroquine. A young patient presenting with toxic maculopathy after 57 g of hydroxychloroquine and a daily dosage of 2 mg/kg body weight prompted us to retrospectively look at our patients examined in this respect over about 1 year.

METHODS

The data of patients who were examined because of chloroquine/hydroxychloroquine intake or a respective maculopathy/retinopathy were retrospectively analysed. The time period was January 2005 until March 2006. Retinal damage was defined by fundus changes and alteration of the multifocal electroretinogram (ERG).

RESULTS

Twenty-one patients--18 women and three men--were examined. The mean age was 51 years (range 6-71). Five of the nine chloroquine-treated patients developed a maculopathy, and one of them developed an additional generalised retinopathy. Of the patients treated by hydroxychloroquine, three of 12 suffered from a maculopathy and one from an additional generalised retinopathy. The cumulative doses leading to retinal damage ranged from 170 g to 1650 g for chloroquine and from 57 g to 1190 g for hydroxychloroquine. The highest cumulative doses without leading to signs of retinopathy were 790 g for chloroquine and 1200 g for hydroxychloroquine.

CONCLUSIONS

There is a high variability of cumulative doses of chloroquine/hydroxychloroquine that lead to a toxic retinopathy. Therefore, early and regular ophthalmologic examinations are recommended. Electrophysiological testing should be performed once a year, corresponding to about 60 g of base with one tablet a day. For electrophysiology, the multifocal ERG has turned out to be the most important test in this regard. However, visual acuity and funduscopy should be performed more frequently.

Neutrophil respiratory burst is decreased in scleroderma and normalized by near-infrared mediated hyperthermia

BACKGROUND

The production of reactive oxygen species (ROS) by fibroblasts has been suggested to contribute to scleroderma pathogenesis. Infrared-mediated hyperthermia has recently been shown to be of benefit in scleroderma.

AIM

As the contribution of neutrophils and monocytes to ROS formation in scleroderma is unknown, we studied respiratory burst in these cell types. We also aimed to test the hypothesis that near-infrared (IRA) treatment may effect burst activity.

METHODS

We determined respiratory burst in patients with scleroderma (n = 22) and age- and sex-matched controls (n = 20) at baseline, and after high-level stimulation by phorbolmyristyl acetate (PMA) and low-level stimulation by non-opsonized zymosan. Respiratory burst was also assessed before and after a series of infrared-mediated hyperthermia treatments.

RESULTS

Unexpectedly, we observed no increase but instead a slight but statistically significant reduction in baseline and zymosan-stimulated respiratory burst in scleroderma neutrophils (P < 0.001) and monocytes (P < 0.005). This decrease in burst activity was nonspecific, as it was also observed in patients with another active inflammatory disease, psoriasis. IRA treatment induced a cell-type-specific normalization of respiratory burst only in neutrophils, but not in monocytes. Intriguingly, neutrophil-specific normalization of ROS formation persisted for 6 weeks after the end of IRA treatment, in concordance with the previously reported clinical responses to this therapy.

CONCLUSION

Neutrophils and monocytes do not exhibit cell-autonomous overproduction of ROS in scleroderma, thereby implicating fibroblasts as main source for clinically relevant ROS accumulation. Furthermore, repeated mild infrared-mediated hyperthermia exerts a lasting cell-type-specific effect on neutrophils.

Infrared-monitored cold response in the assessment of Raynaud's phenomenon

BACKGROUND

Evaluation of treatments for Raynaud's phenomenon (RP) requires objective response parameters in addition to clinical activity scores. Thermographic monitoring of fingertip re-warming after cold challenge has been widely used but usually requires sophisticated equipment. We have previously shown that fingertip re-warming after cold challenge follows a first-order transient response curve that can be described by a single variable, designated tau.

OBJECTIVES

Here, we describe a novel device termed a duosensor, which records the tau value upon cold challenge in an automated manner.

METHODS

We determined tau values in healthy probands, patients with primary or secondary RP associated with autoimmune disease and patients with scleroderma-associated RP following cold challenge, to determine assay variability, sensitivity and specificity.

RESULTS

Duosensor-based thermography exhibited low intraindividual variability in healthy probands. As expected, tau values in RP patients were significantly increased compared with controls (8.08 +/- 3.65 min vs. 3.23 +/- 1.65 min). The duosensor-determined tau value yielded a specificity of 94.6% and predictive value of 95.3% for the presence of RP in a retrospective analysis of 139 patients. Furthermore, in a cohort of scleroderma patients with RP, patient self-assessment of RP severity correlated with tau values.

CONCLUSIONS

Taken together, the present data suggest that tau value determination provides a suitable outcome measure for clinical studies of novel RP treatments. As the duosensor is a simple stand-alone device requiring no supporting equipment and minimal personnel attention, it should allow RP activity monitoring even in clinical settings with minimal technical infrastructure.

Level of NK cytotoxic activity in the elderly aged more than 80 years

A group of healthy volunteers aged 60-93 years, was evaluated with respect to their NK activity. These people have been under careful medical observation for 3 years and were selected according to Senieur Protocol criteria. NK activity of each person was checked at least three times at regular 12-month intervals with the chromium release test and twice at the same interval of time with a single cell cytotoxicity assay. NK activity of 60-79-year-old females was in a similar range of values as that of young females (20-35 years) and was lower than that of the males of the corresponding age groups. The females aged 80-88 years revealed the highest NK activity. The chronically ill 80-88-year-old females, on the other hand, were characterized by a marked decrease of NK activity in relation to their age counterparts. NK activity of both the females and males significantly declined at the age of 89-93 years. The significance of NK activity for survival is discussed.

Ex vivo apoptotic potential of peripheral blood mononuclear cells of the elderly human subject

Studies of immunosenescence have led to a detailed knowledge of immune system dysfunctions in the ageing human being. Apoptosis seems to be one of the process regulating an immune response after the antigenic stimulation. We examined whether commonly used methods of assessing apoptosis in the elderly human subject produce comparable results to young subjects. PBMC of young and elderly volunteers were isolated from the venous blood and cultured for 6 or 24 h with antigens of anti-influenza vaccine or PMA. The intensity of apoptosis was measured using the annexinV test, flow cytometric evaluation of DNA content (sub-G1 peak in DNA histograms), 'ladder' by DNA gel electrophoresis, and fluorescence microscope. Apoptosis in 6 h-lasting cultures of the elderly was more intense in annexinV test, while it was decreased assessing subG1 peak. Additionally, in the aged group, those changes were associated with cell cycle arrest. Our results suggest that the apoptosis after the stimulation with the vaccine antigens seems to be some kind of activation-induced cell death (AICD). Different patterns of apoptosis after stimulation may be associated with the cell cycle arrest of the PBMC in the elderly.

Lower percentage of CD8(high+)CD152(+) but not CD8(high+)CD28(+) T lymphocytes in the elderly may be reverted by interleukin 2 in vitro

An expression of the surface co-stimulatory molecules-the CD152 and the CD28 has been compared between young and old individuals on the CD8(high+) lymphocytes. Sixty five elderly healthy (65-96 years old) and 31 young (19-40 years old) volunteers were examined. An expression of CD152 and CD28 surface antigens was analyzed by flow cytometry ex vivo and on whole blood cell cultures lymphocytes stimulated with interleukin 2 (IL2). The elderly population was characterized by a lower percentage of the CD8(high+) lymphocytes than the young population. The percentages of CD28(+) lymphocytes as well as those of CD8(high+)CD28(+) subpopulation were lower in the old group compared to the young group. The surface expression of CD152 antigen was similar to that of CD28 with a lower percentage of the CD152(+) lymphocytes and CD8(high+)CD152(+) cells in the old group. Stimulation of lymphocytes in vitro with IL2 resulted in an increase of the CD8(high+)CD152(+) cells in the elderly, while it had no effect on lymphocytes of the young group. Our results indicate that lymphocytes of the elderly population are characterized by a lower expression of the surface CD28 and CD152 molecules. An age-related decrease of an expression of the co-stimulatory molecules CD28 and CD152 on the surface of lymphocytes, found in our study, may be compatible with a hypothesis of a 'remodelling' of immune response in the healthy elderly.

MID1, mutated in Opitz syndrome, encodes an ubiquitin ligase that targets phosphatase 2A for degradation

The gene MID1, the mutation of which causes X-linked Opitz G/BBB syndrome (OS, MIM 300000), encodes a microtubule-associated protein (MAP). We show that mutation of MID1 leads to a marked accumulation of the catalytic subunit of protein phosphatase 2A (PP2Ac), a central cellular regulator. PP2Ac accumulation is caused by an impairment of a newly identified E3 ubiquitin ligase activity of the MID1 protein that normally targets PP2Ac for degradation through binding to its alpha4 regulatory subunit in an embryonic fibroblast line derived from a fetus with OS. Elevated PP2Ac causes hypophosphorylation of MAPs, a pathological mechanism that is consistent with the OS phenotype.

Age-related increase of frequency of a new, phenotypically distinct subpopulation of human peripheral blood T cells expressing lowered levels of CD4

Aging is associated with modifications of T-cell phenotype and function, leading to impaired activation in response to both new and recall antigens. It is not known if T-cell activation results in elimination of a number of the CD4 molecules from the cell surface, as is the case with CD3/T-cell receptor complexes, or how aging influences the process. The T cells of young and elderly donors with reduced expression of CD4 were examined to see whether these cells exhibit other phenotypic features suggesting their active state. It was found that T lymphocytes expressing CD4 can be divided into 2 semidiscrete subpopulations: the major (CD4(+)) population, in which the level of expression of CD4 is constant and high, and a minor population (CD4(lo)), in which the expression of CD4 can be up to an order of magnitude lower than on the CD4(+) cells. The proportion of CD4(lo) cells is age dependent and highly variable in the apparently healthy human population, with the expression of CD4 ranging from around 10% of all peripheral blood lymphocytes in the young to more than 30% in the elderly. Lowered expression of CD4 is correlated with a reduced expression of CD3, as well as with a decreased amount of CD28 and CD95Fas. Activation of CD4(lo) cells is suggested by their expression of CD25 and increased amounts of HLA-DR. Phenotypic characteristics of the CD4(lo) T-cell subpopulation suggest that it might be formed by (perhaps chronically) activated, temporarily apoptosis-resistant cells, possibly accumulating in the elderly. (Blood. 2001;98:1100-1107)

Interferon consensus sequence binding protein and interferon regulatory factor-4/Pip form a complex that represses the expression of the interferon-stimulated gene-15 in macrophages

Interferon consensus sequence binding protein (ICSBP), a transcription factor of the interferon (IFN) regulatory factor (IRF) family, binds to the IFN-stimulated response element (ISRE) in the regulatory region of IFNs and IFN-stimulated genes (ISG). To identify target genes, which are deregulated by an ICSBP null-mutation in mice (ICSBP-/-), we have analyzed transcription of an ISRE-bearing gene, ISG15. We have found that although ISG15 expression is unchanged in B cells, it is upregulated in macrophages from ICSBP-/- mice. Three factors, ICSBP, IRF-2, and IRF-4/Pip interact with the ISRE in B cells, however only ICSBP and IRF-4/Pip were found to bind this sequence in macrophages of wild-type mice. Although IRF-4 was considered to be a lymphoid-specific factor, we provide evidence for its role in macrophage gene regulation. Our results suggest that the formation of cell-type-specific heteromeric complexes between individual IRFs plays a crucial role in regulating IFN responses.

Altered development and cytokine responses of myeloid progenitors in the absence of transcription factor, interferon consensus sequence binding protein

Mice deficient for the transcription factor, interferon consensus sequence binding protein (ICSBP), are immunodeficient and develop disease symptoms similar to human chronic myeloid leukemia (CML). To elucidate the hematopoietic disorder of ICSBP(-/-) mice, we investigated the growth, differentiation, and leukemogenic potential of ICSBP(-/-) myeloid progenitor cells in vitro, as well as by cell-transfers in vivo. We report that adult bone marrow, as well as fetal liver of ICSBP-deficient mice harbor increased numbers of progenitor cells, which are hyperresponsive to both granulocyte macrophage colony-stimulating factor (GM-CSF) and G-CSF in vitro. In contrast, their response to M-CSF is strongly reduced and, surprisingly, ICSBP(-/-) colonies formed in the presence of M-CSF are mostly of granulocytic morphology. This disproportional differentiation toward cells of the granulocytic lineage in vitro parallels the expansion of granulocytes in ICSBP(-/-) mice and correlates with a 4-fold reduction of M-CSF receptor expressing cells in bone marrow. Cell transfer studies showed an intrinsic leukemogenic potential and long-term reconstitution capability of ICSBP(-/-) progenitors. Further experiments demonstrated strongly reduced adhesion of colony-forming cells from ICSBP(-/-) bone marrow to fibronectin. In summary, ICSBP(-/-) myeloid progenitor cells share several abnormal features with CML progenitors, suggesting that the distal parts of signaling pathways of these two disorders are overlapping.

The Opitz syndrome gene product, MID1, associates with microtubules

Opitz syndrome (OS) is a genetically heterogeneous disorder characterized by defects of the ventral midline, including hypertelorism, cleft lip and palate, heart defects, and mental retardation. We recently identified the gene responsible for X-linked OS. The ubiquitously expressed gene product, MID1, is a member of the RING finger family. These proteins are characterized by an N-terminal tripartite protein-protein interaction domain and a conserved C terminus of unknown function. Unlike other RING finger proteins for which diverse cellular functions have been proposed, the function of MID1 is as yet undefined. By using the green fluorescent protein as a tag, we show here that MID1 is a microtubule-associated protein that influences microtubule dynamics in MID1-overexpressing cells. We confirm this observation by demonstrating a colocalization of MID1 and tubulin in subcellular fractions and the association of endogenous MID1 with microtubules after in vitro assembly. Furthermore, overexpressed MID1 proteins harboring mutations described in OS patients lack the capability to associate with microtubules, forming cytoplasmic clumps instead. These data give an idea of the possible molecular pathomechanism underlying the OS phenotype.

The upregulation of TNF alpha production is not a generalised phenomenon in the elderly between their sixth and seventh decades of life

The aim of this paper was to analyse the link between the intensity of tumor necrosis factor alpha (TNF alpha) production and the health status of the elderly and to find out whether the age between sixty and seventy is a 'turning point' for the changes in the production of this cytokine. Fifty elderly volunteers (age range: 60-70), twenty-five middle-aged (age range: 36-59) and fifty young (age range: 20-35) were enrolled into the study. Their health status was graded as 'healthy' and 'almost-healthy'. The level of TNF alpha was determined by bioassay, the activity of the TNF alpha gene was analysed in non-stimulated PBMC by the RT-PCR method. The results showed that the production of TNF alpha in the 'healthy' elderly people is not upregulated until the age of sixty-seventy. The 'almost-healthy' elderly are characterised by a higher release of TNF alpha from the cultures of non- and stimulated PBMC and an activation of the TNF alpha gene in the non-stimulated PBMC. Summarising, our results indicate that the deterioration of health status is a prerequisite for an exaggerated TNF alpha production by peripheral blood mononuclear cells of people between the sixth and seventh decades of life.

Increase of interleukin 6 and decrease of interleukin 2 production during the ageing process are influenced by the health status

The ageing process is accompanied by the disregulation of interleukin 2 (IL2) and interleukin 6 (IL6) production. In our paper, we asked whether the age between 60 and 70 years is a turning point for the disregulation of both IL2 and IL6 production. Fifty volunteers 60-70 years old, 25 aged 36-59, and 50 of 20-35 years old were enrolled into the study. Their health status was graded according to the criteria of the Senieur Protocol (SP) as 'healthy' and 'almost-healthy'. The cytokines level was determined in the sera of the volunteers. Moreover, the spontaneous release of IL6 by peripheral blood mononuclear cells (PBMC) and the activity of the IL6 gene in non-stimulated PBMC were also analysed. Cytokine levels were measured by biological assays, mRNA for IL6 was detected by RT-PCR method. The results showed that the production of IL2 is not disregulated in the 'healthy' people until the age of 60-70. People not fulfilling all SP criteria are characterised by a lower level of IL2 in the sera. The overproduction of IL6 into the sera and supernatants from non-stimulated PBMC and PBL as well as the activation of IL6 gene start between the ages 36 and 59 and is more pronounced in the 'almost-healthy'.

Functions of conserved cysteines of soluble guanylyl cyclase

Soluble guanylyl cyclase (sGC), a heme-containing heterodimeric enzyme, is stimulated by NO and catalyzes the formation of the intracellular signaling molecule cGMP. Cysteine residues of sGC have been considered to be important as they were thought to play a significant role in the regulation of the enzyme. The aim of this study was to investigate the possible function of conserved cysteine residues of sGC. Fifteen conserved cysteine residues on sGC were point-mutated to serine, using site-directed mutagenesis. All of the resulting recombinant enzymes were able to synthesize cGMP. Mutation of two cysteines located in the N-terminal, putative heme-binding region of the beta1 subunit yielded proteins that were insensitive to NO. Spectrophotometric analysis of the NO-insensitive mutants purified from Sf9 cells revealed a loss of the prosthetic heme group. Both mutants could be reconstituted with heme and, as a consequence, NO sensitivity of the mutants was restored. Our data show that mutation of two cysteines of the beta1 subunit (Cys-78 and Cys-214) reduces the affinity of sGC for heme. Mutation of the corresponding cysteines on the alpha1 subunit did not alter NO responsiveness, indicating that heme-binding is mainly a feature of the N-terminal domain of the beta1 subunit.

Overactivity of tumor necrosis factor-alpha but not interleukin 6 is associated with low natural killer cytotoxic activity in the elderly

In this paper we asked whether the increased production of two proinflammatory cytokines-tumor necrosis factor-alpha (TNF alpha) and interleukin-6 (IL6) in the absence of the inflammatory stimulus, a phenomenon frequently occurring in the elderly, may contribute to the decrease of natural killer (NK) cytotoxic activity. NK cell activity is a part of a nonspecific immunity directed against infected and transformed cells. We measured the levels of bioactive TNF alpha and IL6 during cytotoxic NK reactions and analyzed the effect of neutralizing monoclonal antibodies anti-TNF alpha and anti-IL6 on the outcome of cytotoxic reaction. Bioactive TNF alpha was produced in higher amounts during cytotoxic reactions of the elderly with low NK activity in comparison with its production by the elderly with high NK activity. Anti-TNF alpha decreased already low cytotoxic responses of the elderly while not having an effect on the cytotoxic potential of high responders. More of the bioactive IL6 was released during cytotoxic reactions of the elderly as compared with young people. There was, however, no relation between the height of NK cytotoxic activity and the amount of IL6. Our results suggest that the increased level of TNF alpha seen in the elderly low NK responders may pose a compensatory mechanism, necessary to keep the highest possible level of NK responses. The increased bioactivity of IL6 during NK reaction of the elderly does not seem to participate in the regulation of the level of NK cytotoxic activity.

A functional heme-binding site of soluble guanylyl cyclase requires intact N-termini of alpha 1 and beta 1 subunits

Soluble guanylyl cyclase, a heterodimeric enzyme, is the most important intracellular target for the signalling molecule nitric oxide (NO). NO stimulates the enzyme by binding to a prosthetic heme group. The identity of the axial heme ligand, however, is still unknown. Here we show that guanylyl cyclase mutated at the residue His 105 on the beta 1 subunit, a mutant that we have shown before to contain no heme after purification [Wedel, B., Humbert, P., Harteneck, C., Foerster, J., Malkewitz, J., Böhme, E., Schultz, G. & Koesling, D. (1994) Proc. Natl Acad. Sci. USA 91, 2592-2596] can be reconstituted with heme. The reconstituted mutant remains NO-insensitive and displays an ultraviolet absorption spectrum consistent with an altered axial coordination. Thus, this residue is a strong candidate for the axial heme-ligating residue and appears to be necessary for NO stimulation. Apart from the axial heme ligand, the role of the enzyme's two subunits, alpha 1 and beta 1, in heme binding has not been clarified to date. To address this question, we purified mutant heterodimers in which the non-conserved amino termini of either alpha 1 (131 residues deleted), or beta 1 (64 residues) have been deleted. These deletion mutants had previously been found to be marginally (alpha 1 truncated) or not at all NO sensitive (beta 1 truncated) in cytosolic fractions [Wedel, B., Harteneck, C., Foerster, J., Friebe, A., Schultz, G. & Koesling, D. (1995) J. Biol. Chem. 270, 24871-24875]. Here, we show that the purified enzyme truncated on alpha 1 has a significantly reduced capacity to bind heme which explains the reduced NO sensitivity. By contrast, the beta 1-truncated enzyme binds an amount of heme comparable to the wild type but is only marginally NO-responsive and displays a shift in the heme ultraviolet absorption maximum indicative of altered heme coordination. In conclusion, the heme binding site of soluble guanylyl cyclase requires the presence of both subunits in full length to be able to bind wild-type quantities of heme and to be capable of mediating the NO-heme-induced stimulation. Despite some structural similarity, both subunits appear to participate differently in NO-heme-mediated enzyme regulation.

Functional domains of soluble guanylyl cyclase

Soluble guanylyl cyclase is a heterodimer consisting of an alpha and beta subunit and stimulation occurs upon binding of NO to a prosthetic group. Little is known about the localization of catalytic and regulatory domains within the subunits of soluble guanylyl cyclase. We used deletion mutagenesis to identify the regions of alpha 1 and beta 1 subunits that are responsible for cGMP production or NO-heme-mediated activation. The amino terminus of the beta 1 subunit was necessary for NO stimulation since deletion of the 64 NH2-terminal amino acids resulted in a mutant with intact basal activity but complete loss of NO activation. The amino terminus of the alpha 1 subunit also appeared to be essential for NO sensitivity since deletion of 131 NH2-terminal amino acids of alpha 1 led to markedly reduced NO activation. These results suggest that NH2-terminal regions of alpha 1 and beta 1 are involved in NO-heme-mediated signal transduction. The NH2 terminally truncated beta 1 subunit exerted a dominant negative effect exclusively on the NO-stimulated activity of the wild type enzyme, further underlining that the regulatory domain is located within the NH2 terminus of the enzyme. Aside for the structural implications, the mutant represents a powerful tool to investigate nitric oxide-sensitive signaling pathways. Coexpression of the COOH-terminal halves of alpha 1 and beta 1 were sufficient for basal cGMP production while either of the halves expressed alone was inactive. Therefore the COOH-terminal regions appear to contain sufficient information for dimerization and basal enzymatic activity. Thus, we provide the first evidence that the regulatory and catalytic properties of soluble guanylyl cyclase can be attributed to different regions of the subunits and that the catalytic domain can be functionally expressed separately from the NH2-terminal regulatory domain. Taken together with findings on the membrane bound enzyme form, guanylyl cyclases, appear to resemble fusion proteins where different regulatory domains have been joined with a common cGMP-forming segment.

Application of AGNPS to model nutrient generation rates under different farming management practices at the Gunnedah Research Centre catchment

Data collected at a conservation tillage trial site operational between 1971 and 1986 were used to assess the performance of the Agricultural Non-Point Source model (AGNPS). Eight trial plots, each of about 1 ha (average slope of 3.8%), were established on the black earths of paddock 2 at the Gunnedah Research Centre, New South Wales. The plots were subjected in pairs to stubble-burning, stubble incorporation, stubble-mulching, and no-tillage treatments. Runoff and peak flow rate from the plots, resulting from 5 rainfall events between 1982 and 1986, were used to calibrate the hydrology module of AGNPS. Hydrologic simulations for each plot and associated tillage treatment performed after calibration showed that conservation farming practices could effectively reduce runoff and peak flow rate. AGNPS was also used to simulate nutrient generation rates, defined as the transport of soluble and sediment-adsorbed nitrogen and phosphorus in runoff and sediment discharge, for the whole catchment for a number of rainfall events. The model predicted that nutrient movement could be reduced using best management practices, including the implementation of contour banks, contour cultivation, and no tillage. Additional information related to soil chemical properties and pore/surface water nutrient content could improve model performance.