Immuno-modulating properties of Tulathromycin in porcine monocyte-derived macrophages infected with porcine reproductive and respiratory syndrome virus.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-stranded RNA virus that grows in macrophages and causes acute pneumonia in pigs. PRRSV causes devastating losses to the porcine industry. However, due to its high antigenic variability and poorly understood immunopathogenesis, there is currently no effective vaccine or treatment to control PRRSV infection. The common occurrence of PRRSV infection with bacterial infections as well as its inflammatory-driven pathobiology raises the question of the value of antibiotics with immunomodulating properties for the treatment of the disease it causes. The macrolide antibiotic Tulathromycin (TUL) has been found to exhibit potent anti-inflammatory and immunomodulating properties in cattle and pigs. The aim of this study was to characterize the anti-viral and immunomodulating properties of TUL in PRRSV-infected porcine macrophages. Our findings indicate that blood monocyte-derived macrophages are readily infected by PRRSV and can be used as an effective cellular model to study PRRSV pathogenesis. TUL did not change intracellular or extracellular viral titers, not did it alter viral receptors (CD163 and CD169) expression on porcine macrophages. In contrast, TUL exhibited potent immunomodulating properties, which therefore occurred in the absence of any direct antiviral effects against PRRSV. TUL had an additive effect with PRRSV on the induction of macrophage apoptosis, and inhibited virus-induced necrosis. TUL significantly attenuated PRRSV-induced macrophage pro-inflammatory signaling (CXCL-8 and mitochondrial ROS production) and prevented PRRSV inhibition of non-opsonized and opsonized phagocytic function. Together, these data demonstrate that TUL inhibits PRRSV-induced inflammatory responses in porcine macrophages and protects against the phagocytic impairment caused by the virus. Research in live pigs is warranted to assess the potential clinical benefits of this antibiotic in the context of virally induced inflammation and tissue injury.

Markers to differentiate between Kaposi's sarcoma and tuberculous pleural effusions in HIV-positive patients.

BACKGROUND: Kaposi's sarcoma (KS) and tuberculosis (TB) commonly cause pleural effusions in high human immunodeficiency virus (HIV) burden resource-limited countries. Differentiating between them is challenging, as pleural biopsy and TB culture are rarely available. OBJECTIVES: To identify markers to differentiate between TB effusions and KS effusions in HIV-positive patients, and to compare liquid culture and Xpert MTB/RIF in pleural fluid. METHODS: Fifty HIV-positive patients with pleural effusions recruited in Malawi underwent pleural ultrasound and aspiration. Fluid visual inspection, cell count, bacterial culture, glucose/protein, solid and liquid TB culture and Xpert were performed. RESULTS: The mean age of the patients was 32 years; 30/50 (60%) were male and 29 (58%) had cutaneous/oral KS. Thirteen (26%) pleural fluid samples were liquid culture-positive for TB, while 9/13 (69%) were Xpert-positive. Three (10.3%) KS patients had culture-positive TB effusions; 17 (58.6%) had KS effusions. The relative risk of TB in KS patients increased with limited KS, loculated fluid and low glucose. Eleven (52.3%) non-KS patients had culture-positive TB effusions associated with male sex, straw-coloured fluid and fibrin stranding on ultrasound. CONCLUSIONS: KS patients were most likely to have KS effusion, but TB should be considered. Most non-KS patients had TB, supporting the use of World Health Organization guidelines. Xpert identified two thirds of liquid culture-positive results.

Validation of the haemoglobin colour scale for screening blood donors in Malawi.

BACKGROUND: In 2009 Malawi introduced a new protocol to screen potential blood donors for anaemia, using the WHO Haemoglobin Colour Scale (HCS) for initial screening. Published studies of the accuracy of the HCS to screen potential blood donors show varying levels of accuracy and opinion varies whether this is an appropriate screening test. The aim of the study was to assess the validity of the HCS, as a screening test, by comparison to HemoCue in potential blood donors in Malawi. STUDY DESIGN AND METHODS: This was a blinded prospective study in potential blood donors aged over 18 years, at Malawi Blood Transfusion Service in Blantyre, Malawi. Capillary blood samples were analysed using the HCS and HemoCue, independent of each other. The sensitivity and specificity of correctly identifying ineligible blood donors (Hb ≤ 12 g/dL) were calculated. RESULTS: From 242 participants 234 (96.7%) were correctly allocated and 8 (3.3%), were wrongly allocated on the basis of the Haemoglobin Colour Scale (HCS) compared to HemoCue, all were subjects that were wrongly accepted as donors when their haemoglobin results were ≤ 12.0 g/dL. This gave a sensitivity of 100% and specificity of 96.7% to detect donor eligibilty. The negative predictive value of the HCS was 100% but the positive predictive value to identify ineligible donors on the basis of anaemia was only 20%. CONCLUSIONS: Initial screening with the HCS correctly predicts eligibility for blood donation in the majority of potential blood donors at considerable cost saving compared with use of HemoCue as the first line anaemia screening test, however, by this method a small number of anaemic patients were allowed to donate blood.

The prevalence of renal impairment among adults with early HIV disease in Blantyre, Malawi.

We determined the prevalence of renal impairment and possible HIV-associated nephropathy (HIVAN) in adults with World Health Organization (WHO) stages I or II HIV, presenting to the antiretroviral therapy (ART) clinic in a central hospital in Malawi. We enrolled 526 ART-naïve subjects, 67% women, median age 34 (17-73) years and mean CD4 count 305 (3-993) cells/µL. Blood pressure, weight, urine dipstick and microscopy, CD4 cell count and serum creatinine were measured. Creatinine clearance (CrCL) was estimated using the Cockcroft-Gault equation. Possible HIVAN was diagnosed based on levels of proteinuria and CrCl. In all, 23.3% had proteinuria (≥ 1+). 57.4% had reduced CrCl (< 90 mL/minute): 18.8% had moderate (CrCl 30-59 mL/minute) and 2.2% severe (CrCl <30 mL/minute) renal dysfunction. Extrapolating from renal biopsy studies that confirmed HIVAN, the proportion of patients with HIVAN in our clinic ranges from 1.8-21.2%. We conclude that renal impairment was common, though rarely severe, among HIV-infected adults with clinically non-advanced HIV disease. Renal dysfunction has been demonstrated to be a risk factor for (early) mortality. These results are relevant for ART programmes, such as those in Malawi, where renal function is not routinely assessed.

Amelanotic malignant melanoma disguised as a diabetic foot ulcer.

UNLABELLED: BACKGROUND/CASE REPORT A female patient with diet-controlled Type 2 diabetes mellitus, presented with disseminated malignancy. She had a 15-year history of a diabetic foot ulcer, which was subsequently found to be an amelanotic malignant melanoma. She had recently received immunosuppressive treatment for an episode of nephrotic syndrome secondary to focal segmental glomerulosclerosis. CONCLUSIONS: This case raises two important points. Firstly, whether non-healing diabetic foot ulcers should be biopsied, and secondly, whether the spread of the malignant melanoma was precipitated by immunosuppressive treatment.

Changes in growth hormone, insulin, insulinlike growth factors (IGFs), and IGF-binding protein-1 in chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is characterized by severe physical and mental fatigue of central origin. Similar clinical features may occur in disorders of the hypothalamopituitary axis. The aim of the study was to determine whether patients with CFS have abnormalities of the growth hormone/insulinlike growth factor (GH-IGF) axis basally or following hypothalamic stimulation with insulin-induced hypoglycemia. We compared levels of GH, IGF-I, IGF-II, IGF-binding protein-1 (IGFBP-1), insulin, and C-peptide in nondepressed CFS patients and normal controls. We found attenuated basal levels of IGF-I (214 +/- 17 vs. 263.4 +/- 13.4 micrograms/L, p = .036) and IGF-II (420 +/- 19.8 vs. 536 +/- 24.3 micrograms/L, p = .02) in CFS patients and a reduced GH response to hypoglycemia (peak GH; 41.9 +/- 11.5 vs. 106.0 +/- 25.6 mU/L, p = .017). Insulin levels were higher (7.6 +/- 1.0 vs. 4.3 +/- 0.8 mU/L, p = .02) and IGFBP-1 levels were lower (19.7 +/- 4.6 vs. 43.2 +/- 2.7 mg/L, p = .004) in CFS patients compared with controls. This study provides preliminary data abnormalities of the GH-IGF axis in CFS. It is not apparent whether these changes are components of a primary pathological process or are acquired secondary to behavioral aspects of CFS such as reduced physical activity.

Morbidity and disability in elderly Zimbabweans.

BACKGROUND: the population aged over 60 years in Zimbabwe is expanding. Despite the likely increased demand on medical services that this will bring, little is known about the health needs of this elderly population. OBJECTIVE: to record the prevalence of disability (impairment of activities of daily living), subjective morbidity (symptoms), the social circumstances and the utilization of health services in a group of elderly Zimbabweans. DESIGN: cross-sectional community survey. SETTING: a remote rural area in North Eastern Zimbabwe and two urban townships located approximately 80 km from Harare. SUBJECTS: 278 subjects (154 women, 174 rural), aged > 60 years (range 60-92) living at home. METHOD: subjects were selected by random cluster sampling. They were assessed in a structured interview and underwent physical examination including visual acuity, inspection for cataracts and assessment of mobility. RESULTS: less than 4% experienced difficulty with self-maintenance activities of daily living, but 30% had difficulty with instrumental activities. The former were all visually impaired and both visual and mobility problems contributed to the latter. Elderly people experienced many symptoms but had inadequate access to health services and used medication infrequently. Subjects were mainly self-sufficient for financial income and 60% still worked. They had declining resources with age and received little help from the social welfare department. Their health and functional abilities deteriorated with age but it was older subjects who had most difficulty getting to the clinic. Simple measures such as cataract surgery and analgesics were available only to the minority or not at all. CONCLUSIONS: this study highlights problem areas where simple, low-cost measures could make a difference to the morbidity and disability of elderly Zimbabweans.

The isoform-specific expression of the tri-iodothyronine receptor in osteoblasts and osteoclasts.

Hyperthyroidism is associated with an increase in both osteoblast and osteoclast activity. We have previously shown that, in vitro, osteoclasts do not respond directly to tri-iodothyronine to increase bone resorption but that the effect is mediated by another bone cell, probably the osteoblast. To investigate this issue further we have studied the isoform-specific expression of thyroid receptor (TR) protein in human osteoclasts derived from an osteoclastoma (giant cell tumour of bone) and the expression of TR mRNA and protein in the osteoblastic cell lines MG 63 and UMR 106. Three major TR receptor variants have been described; TR alpha 1 and TR beta are functional receptors whereas c-erbA alpha 2 is a non-functional variant. Northern blot analysis using [32P]-cDNA probes against human TR alpha 1, c-erbA alpha 2 and TR beta demonstrated specific binding of these probes to mRNA from MG 63 and UMR 106. mRNA for all three receptor variants was observed in both cell lines, in UMR 106 multiple mRNA transcripts were present for TR alpha 1 and TR beta. Immunohistochemical staining with antibodies recognizing a common TR alpha epitope and specific c-erbA alpha 2 and TR beta epitopes extended these observations by demonstrating receptor protein in both osteoblasts and osteoclasts. These findings are consistent with previous observations of TR expression in osteoblast-like-cells and are the first direct demonstration of TR in osteoclasts.

Contrasting neuroendocrine responses in depression and chronic fatigue syndrome.

Hypothalamic-pituitary-adrenal (HPA) axis and central 5-HT function were compared in chronic fatigue syndrome (CFS), depression and healthy states. 10 patients with CFS and 15 patients with major depression were matched for age, weight, sex and menstrual cycle with 25 healthy controls. Baseline-circulating cortisol levels were highest in the depressed, lowest in the CFS and intermediate between the two in the control group (P = 0.01). Prolactin responses to the selective 5-HT-releasing agent d-fenfluramine were lowest in the depressed, highest in the CFS and intermediate between both in the healthy group (P = 0.01). Matched pair analysis confirmed higher prolactin responses in CFS patients than controls (P = 0.05) and lower responses in depressed patients than controls (P = 0.003). There were strong inverse correlations between prolactin and cortisol responses and baseline cortisol values. These data confirm that depression is associated with hypercotisolaemia and reduced central 5-HT neurotransmission and suggest that CFS may be associated with hypocortisolaemia and increased 5-HT function. The opposing responses in CFS and depression may be related to reversed patterns of behavioural dysfunction seen in these conditions. These findings attest to biological distinctions between these disorders.

A histomorphometric study of bone changes in thyroid dysfunction in rats.

Clinical studies in thyrotoxicosis reveal a state of high bone turnover leading, eventually, to osteoporosis. Recently there has been concern that thyroxine (T4) treatment may have a similar effect on bone. Rat models have been used to study the effects of T4 on bone, but the majority of studies have looked at the effects of T4 after only 3 weeks of treatment. The aim of this study was to evaluate histomorphometric changes in rats after 12 weeks of thyroxine overtreatment or 12 weeks of hypothyroidism compared with untreated control animals. Animals received either T4 200 micrograms/kg per day, 0.1% propylthiouracil, or vehicle for 12 weeks. Tetracycline was administered 1 week and 3 weeks prior to killing. Iliac crest bone was used for histomorphometry. Serum T4 measurements (taken at killing) confirmed hyper- and hypothyroidism in the appropriate animal groups (between group difference p < 0.001 by ANOVA). In hyperthyroid animals there was an increase in mineral apposition rate (MAR; 0.94 vs. 0.59 microns/day, p < 0.001) and mineral formation rate (MFR/BS; 0.24 vs. 0.12 x 10(-2) micron3/micron2 per day, p < 0.001) and a slight increase in eroded surfaces (ES/BS%; 1.54 vs. 1.36, p < 0.05) compared with controls, consistent with previous in vitro and in vivo observations. In hypothyroid rats there was a marked reduction in osteoid surfaces (OS/BS%; 1.7 vs. 24.8, p < 0.001) and MAR (0.3 vs. 0.59 micrograms/day, p < 0.001), a reduction in ES/BS% (0.51 vs. 1.36, p < 0.05), and an increase in cancellous bone volume (BV/TV%; 30.29 vs. 19.6, p < 0.05), suggesting that thyroid hormones are a requirement for normal bone turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuroendocrine responses to d-fenfluramine and insulin-induced hypoglycemia in chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is a disorder characterized by severe physical and mental fatigue and fatiguability of central rather than peripheral origin. We hypothesized that CFS is mediated by changes in hypothalamopituitary function and so measured the adrenocorticotrophic hormone (ACTH), cortisol, growth hormone, and prolactin responses to insulin-induced hypoglycemia, and the ACTH, cortisol, and prolactin responses to serotoninergic stimulation with dexfenfluramine in nondepressed CFS patients and normal controls. We have shown attenuated prolactin responses to hypoglycemia in CFS. There was also a greater ACTH response and higher peak ACTH concentrations (36.44 +/- 4.45 versus 25.60 +/- 2.78 pg ml), whereas cortisol responses did not differ, findings that are compatible with impaired adrenal cortical function. This study provided evidence for both pituitary and adrenal cortical impairment in CFS and further studies are merited to both confirm and determine more precisely their neurobiological basis so that rational treatments can be evolved.

Tri-iodothyronine stimulates rat osteoclastic bone resorption by an indirect effect.

Tri-iodothyronine (T3) increases bone resorption in vivo and in vitro. In order to understand further the mechanisms by which this occurs we studied the effects of T3 at concentrations in the range of 1 pmol/l-1 mumol/l on bone resorption by osteoclasts isolated from neonatal rat long bones. Osteoclasts were disaggregated and incubated either with or without UMR 106 cells or with mixed bone cells. We found that there was no effect of T3 on bone resorption by osteoclasts incubated alone or co-cultured with UMR 106 cells. However, in culture with mixed bone cells there was a significant relationship between the concentration of T3 and bone resorption (r = 0.54, P = 0.01). The greatest effect was observed at a T3 concentration of 1 mumol/l at which a 1.8-fold increase in resorption was seen compared with control (P less than 0.005; paired t-test). We conclude that the ability of T3 to increase osteoclastic bone resorption is not due to a direct action of T3 on osteoclasts but is mediated by another cell present in bone. The observation that UMR 106 cells are unable to mediate this effect suggests that either the mediating cell is not osteoblastic or the phenotype of UMR 106 does not conform to the phenotype of osteoblastic cells that mediate the T3 responsiveness of bone.