The dichotomy of the systemic and local cytokine responses of mucosal leishmaniasis patients in Sudan: A pilot study

Sudanese mucosal leishmaniasis (ML) is a rare clinical form of leishmaniasis and characterized by persistent ulcer of the oral and/or the nasal mucous membranes caused by Leishmania donovani. No data is available about the systemic and local immune responses in mucosal leishmaniasis. This study aimed to measure the systemic and the local cytokines responses of Sudanese ML patients compared to cured cutaneous leishmaniasis patients (Leishmanin skin test positive, LST+ve) and unexposed healthy controls (Leishmanin skin test negative, LST-ve). Six parasitological confirmed ML patients, 7 LST+ve, and 6 LST-ve were enrolled. Systemic Th-1 (IFN-γ and TNF-α), Th-2 (IL-10 and IL-13), Treg (TGF-β1), and inflammatory cytokines IL-6 and IL-8 concentration were measured in the supernatant of whole blood samples following stimulation with live L. donovani promastigotes using ELISA. Local intralesion IL-10, IFN-γ, and IL-13 expression was measured using Real Time PCR. A significant high concentrations of IFN-γ, TNFα, IL-10, TGFβ, IL-6, and IL-8 were detected in the supernatant of stimulated whole blood samples of ML patients compared with the LST+ve and LST-ve controls. Using Real Time-PCR and primers for various cytokines, a significant high expression of TH2 cytokines IL-10 and IL-13 mRNA was detected in contrast to a low TH1 cytokine IFN-γ mRNA in the mucosal lesion. There is a clear dichotomy in the cytokine response during Mucosal leishmaniasis. A significantly high TH1, inflammatory and Treg cytokines response is produced systemically, in contrast to a significant high TH2 cytokines response in the mucosal lesion.

Expression profiling of Sudanese visceral leishmaniasis patients pre- and post-treatment with sodium stibogluconate

Visceral leishmaniasis (VL) in Sudan caused by Leishmania donovani is fatal in susceptible individuals if untreated. Treatment with sodium stibogluconate (SSG) leads to post-kala-azar dermal leishmaniasis (PKDL) in 58% of patients. Here, Affymetrix microarrays were used to identify genes differentially expressed in lymph nodes (N=9 paired samples) pre- and post-treatment with SSG. Using the Bioconductor package limma, 438 genes from 28 869 post-quality-control probe sets were differentially expressed (P_nominal ≤.02) post- vs pretreatment. Canonical pathway analysis using Ingenuity Pathway Analysis™ identified "role of nuclear factor of activated T-cell in regulation of immune response" (P_nominal =1.35×10^-5 ; P_BH-adjusted =4.79×10^-3 ), "B-cell development" (P_nominal =2.04×10^-4 ; P_BH-adjusted =.024), "Fcγ receptor-mediated phagocytosis in macrophages and monocytes" (P_nominal =2.04×10^-4 ; P_BH-adjusted =.024) and "OX40 signalling" (P_nominal =2.82×10^-4 ; P_BH-adjusted =.025) as pathways differentially regulated post- vs pretreatment. Major network hub genes included TP53, FN1, MYC, BCL2, JUN, SYK, RUNX2, MMP1 and ACTA2. Top endogenous upstream regulators included IL-7 (P=2.28×10^-6 ), TNF (P=4.26×10^-6 ), Amyloid Precursor Protein (P=4.23×10^-5 ) and SPI1/PI.1 (P=1.17×10^-7 ). Top predicted chemical drug regulators included the flavonoid genistein (P=4.56×10^-7 ) and the quinoline alkaloid camptothecin (P=5.14×10^-5 ). These results contribute to our understanding of immunopathology associated with VL and response to SSG treatment. Further replication could identify novel therapeutic strategies that improve on SSG treatment and reduce the likelihood of progression to PKDL.

The 5q31 region in two African populations as a facet of natural selection by infectious diseases

Cases of extreme natural selection could lead either to rapid fixation or extinction of alleles depending on the population structure and size. It may also manifest in excess of heterozygosity and the locus concerned will be displaying such drastic features of allele change. We suspect the 5q31 in chromosome 5 to mirror situation of such extreme natural selection particularly that the region encompasses genes of type 2 cytokine known to associate with a number of infectious and non-infectious diseases. We typed two sets of single nucleotide polymorphisms (SNPS) in two populations: an initial limited set of only 4 SNP within the genes of IL-4, IL-13, IL-5 and IL-9 in 108 unrelated individuals and a replicating set of 14 SN P in 924 individuals from the same populations with disregard to relatedness. The results suggest the 5q31 area to be under intense selective pressure as indicated by marked heterozygosity independent of Linkage Disequilibrium (LD); difference in heterozygosity, allele, and haplotype frequencies between generations and departure from Hardy-Weinberg expectations (DHWE). The study area is endemic for several infectious diseases including malaria and visceral leishmaniasis (VL). Malaria caused by Plasmodiumfalciparum, however, occurs mostly with mild clinical symptoms in all ages, which makes it unlikely to account for these indices. The strong selection signals seems to emanate from recent outbreaks of VL which affected both populations to varying extent.

Blindness following visceral leishmaniasis: a neglected post-kala-azar complication

Visceral leishmaniasis (VL) is an important cause of morbidity and mortality that affects multiple organs. Post-kala-azar ocular involvement is a serious complication that can manifest as blepharo-conjuctivitis or pan-uveitis. Failure of prompt diagnosis and treatment can result in blindness. We report five cases with pan-uveitis that followed the successful treatment of VL and consequent post-kala-azar dermal leishmaniasis were presented. Two patients lost their sight permanently but the rest were successfully treated. A high index of suspicion and prompt treatment are of paramount importance in order to avoid blindness following post-kala-azar ocular uveitis.

Interleukin 10 gene polymorphisms and development of post kala-azar dermal leishmaniasis in a selected sudanese population

Background

Post kala-azar dermal leishmaniasis (PKDL) is a cutaneous form of disease that develops at variable times after individuals have received treatment for clinical visceral leishmaniasis (VL). The study aimed to investigate the possible role of interleukin 10 (IL−10) and development of PKDL.

Methods

77 families composed of 41 complete case-parent trios and 36 case-parent pairs from the Masalit ethnic group were genotyped for 3 IL10 promoter polymorphisms: −1082A/G, −819C/T and −592C/A.

Results

Single point analysis using the transmission disequilibrium test showed no evidence of association between any of these IL10 promoter single nucleotide polymorphisms (SNPs) and development of PKDL. Haplotype analysis performed using TRANSMIT showed borderline significance between PKDL and the haplotype AA across −592C/A and −1082A/G (p = 0.053). Haplotypes GCC (0.33) and ATA (0.30) were the common haplotypes in this Sudanese population. Allele frequencies for the 3 SNPs differed significantly in Sudan compared to other African (Gambian, Malawian, YRI) populations.

Conclusion

There is no evidence for an association between 3 SNPs in the IL10 gene promoter and susceptibility to PKDL in the Masalit ethnic group in Sudan, although some evidence for haplotype association was observed.

Changes in tissue levels of growth hormone, insulin-like growth factor-I, and somatostatin in the femurs of hind-limb immobilized rats

Immobilization of an extremity causes skeletal muscle atrophy and a dramatic increase in bone resorption. Growth hormone (GH) is known to play an important role in bone remodeling mediated in part by local insulin-like growth factor-I (IGF-I). In this study, we investigated changes in the levels of GH and IGF-I peptide in bone extracts from the femur after hind-limb immobilization for 5 days, 2, 4, and 8 weeks. The levels of somatostatin, which interacts with GH, were also measured in the bone extracts. GH levels increased after 8 weeks of hind-limb immobilization whereas the IGF-I concentrations increased after 2 weeks, but returned to control levels at 4 weeks, and decreased after 8 weeks of immobilization. The somatostatin levels in the bone extracts increased only after 8 weeks of hind-limb immobilization. Our findings suggest that, after hind-limb immobilization, changes in the concentrations of GH, IGF-I, and somatostatin in bone may mediate bone resorption either directly or through interaction with other factors.

Dichotomy of protective cellular immune responses to human visceral leishmaniasis

Healing/protective responses in human visceral leishmaniasis (VL) are associated with stimulation/production of Th1 cytokines, such as interferon IFN-gamma, and conversion in the leishmanin skin test (LST). Such responses were studied for 90 days in 44 adult healthy volunteers from VL non-endemic areas, with no past history of VL/cutaneous leishmaniasis (CL) and LST non-reactivity following injection with one of four doses of Alum-precipitated autoclaved Leishmania major (Alum/ALM) +/- bacille Calmette-Guerin (BCG), a VL candidate vaccine. The vaccine was well tolerated with minimal localized side-effects and without an increase in antileishmanial antibodies or interleukin (IL)-5. Five volunteers (5/44; 11.4%) had significant IFN-gamma production by peripheral blood mononuclear cells (PBMCs) in response to Leishmania antigens in their prevaccination samples (P = 0.001) but were LST non-reactive. On day 45, more than half the volunteers (26/44; 59.0%) had significantly high LST indurations (mean 9.2 +/- 2.7 mm) and high IFN-gamma levels (mean 1008 +/- 395; median 1247 pg/ml). Five volunteers had significant L. donovani antigen-induced IFN-gamma production (mean 873 +/- 290; median 902; P = 0.001), but were non-reactive in LST. An additional five volunteers (5/44; 11.4%) had low IFN-gamma levels (mean 110 +/- 124 pg/ml; median 80) and were non-reactive in LST (induration = 00 mm). The remaining eight volunteers had low IFN-gamma levels, but significant LST induration (mean 10 +/- 2.9 mm; median 11). By day 90 the majority of volunteers (27/44; 61.4%) had significant LST induration (mean 10.8 +/- 9.9 mm; P < 0.001), but low levels of L. donovani antigen-induced IFN-gamma (mean 66.0 +/- 62 pg/ml; P > 0.05). Eleven volunteers (11/44; 25%) had significantly high levels of IFN-gamma and LST induration, while five volunteers had low levels of IFN-gamma (<100 pg/ml) and no LST reactivity (00 mm). One volunteer was lost to follow-up. In conclusion, it is hypothesized that cellular immune responses to human VL are dichotomatous, and that IFN-gamma production and the LST response are not in a causal relationship. Following vaccination and probably cure of VL infection, the IFN-gamma response declines with time while the LST response persists. LST is a simple test that can be used to assess candidate vaccine efficacy.

Diagnosis of tuberculous lymphadenitis by FNAC, microbiological methods and PCR: a comparative study

Despite its usefulness in the diagnosis of tuberculous lymphadenitis, fine needle aspiration cytology (FNAC) faces several limitations, and its sensitivity and specificity are not well established. The diagnostic accuracy and limitations of FNAC were studied in comparison with conventional microbiological methods and polymerase chain reaction (PCR). Sixty patients with lymphadenopathy and a clinical diagnosis of tuberculous lymphadenitis were subjected to FNA. The aspirate was used for cytological examination, Ziehl-Neelsen staining, mycobacterial culture and PCR. PCR was performed using two sets of oligonucleotide primers for Mycobacterium tuberculosis and a single primer for M. bovis species. The results of FNAC, microbiological methods and PCR correlated with the clinical outcome after follow-up for an average period of 24 months. Twenty-five cases (41.6%) were treated and responded well to anti-tuberculosis therapy, among them 17 were correctly diagnosed by FNAC (68%), eight by microbiological methods (32%) and 24 by PCR (96%). When PCR is considered the gold standard, FNAC predicted the correct diagnosis in 62% of cases with a high false negative rate (38%) due to the absence of granuloma/necrosis in smears from cases of early tuberculosis. In the latter group PCR proved to be the most valuable and a diagnostic success of 100% was achieved when FNAC and PCR were combined. In addition, PCR allowed immediate characterization of M. tuberculosis in the vast majority (96.2%) of cases in the study population.

Adjuvant-induced arthritis: IL-1 beta, IL-6 and TNF-alpha are up-regulated in the spinal cord

Adjuvant-induced arthritis (AIA) is a widely used animal model of human rheumatoid arthritis (RA). We have previously shown that increased neuropeptide expression is observed in the spinal cord of AIA rats. To study the potential role of cytokines in the spinal cord of AIA, we wanted to determine whether there are changes of glial and cytokine expression (IL-1 beta, IL-6, TNF-alpha and IFN-gamma) in the spinal cord of AIA rats. Our data indicated that macroglia and MHC class II immunostaining were enhanced, astrocytes expressing GFAP were increased in number and immunostaining intensity. Using in situ hybridization and immunohistochemical methods, both mRNA and protein levels of IL-1 beta, IL-6 and TNF-alpha were significantly increased in the spinal cord of arthritic rats. Increased cytokine expression was presented in the reactive astrocytes and microglia.

Effects of short- and long-term rat hind limb immobilization on spinal cord insulin-like growth factor-I and its receptor

In this study we investigated changes in the spinal cord insulin-like growth factor-I peptide (IGF-I) and its receptors (IGF-IR) after hind limb immobilization for 5 days, 2, 4, and 8 weeks. Moreover, effects on IGF-I and nicotinic cholinergic receptors (nAChRs) in two types of skeletal muscle were also investigated. IGF-I levels were measured by radioimmunoassay (RIA) whereas IGF-IR and nAChRs were measured by quantitative receptor autoradiography. Spinal cord IGF-I levels decreased significantly after 5 days, 2 and 4 weeks of immobilization, whereas IGF-IR increased significantly after 4 and 8 weeks compared to controls. In skeletal muscles, nAChRs increased significantly after 5 days and 2 weeks in the soleus (SOL) and tibialis anterior (TIB) muscles, respectively, and continued up to 8 weeks in both muscles. IGF-I concentration decrease significantly after 4 and 8 weeks in the SOL and TIB muscles, respectively. Despite the normal levels of IGF-I in both muscles at the early time points (5 days and 2 weeks), low levels of IGF-I were observed concurrently in the spinal cord ipsilateral to the immobilized limb. Our findings suggest that the early decrease in the IGF-I level and the late upregulation in the IGF-IR in the spinal cord might represent a nervous system response to disuse.

Increased levels of somatostatin in rat ankles with adjuvant arthritis

Levels of somatostatin were investigated in the ankles and spinal cords of rats suffering from acute and chronic adjuvant arthritis. As measured by radioimmunoassay, somatostatin showed significantly higher concentrations only in chronic arthritic ankles. No significant difference was observed in somatostatin levels between the spinal cords of normal and arthritic groups. Using immunohistochemical labeling and electron microscopy, we observed increased somatostatin labeling in the mature bone matrix, monocytes, and polymorphonuclear cells of bone marrow and macrophage-like synovial cells of chronically arthritic rats. Understanding the mechanism(s) which lead to increased somatostatin in chronic arthritic joints may result in more effective treatment methods.

Suppression of autoimmune neuritis in IFN-gamma receptor-deficient mice

Experimental autoimmune neuritis (EAN) is an animal model of the human disease Guillain-Barré syndrome. In this autoimmune inflammatory disease, CD4(+) T cells mediate demyelination in the peripheral nervous system (PNS). Infiltrating macrophages and T cells as well as cytokines like interferon (IFN)-gamma are intimately involved in causing pathogenic effects. To investigate the role of IFN-gamma in cell-mediated EAN, IFN-gamma receptor-deficient mutant (IFN-gammaR(-/-)) C57BL/6 mice and corresponding wild-type mice were immunized with P0 peptide 180-199, a purified component of peripheral nerve myelin, and Freund's complete adjuvant. IFN-gammaR(-/-) mice exhibited later onset of clinical disease. The disease was also less severe than in wild-type mice. Fewer IL-12-producing but more IL-4-producing cells were found in sciatic nerve sections from IFN-gammaR(-/-) mice than from wild-type mice on day 24 postimmunization, i.e., at the peak of clinical EAN. At the same time, IFN-gammaR(-/-) mice had less infiltration of inflammatory cells, including macrophages, CD4(+) T cells, and monocytes, into sciatic nerve tissue and less demyelination. However, numbers of IFN-gamma-secreting cells from the spleen were significantly augmented in the IFN-gammaR(-/-) mice, reflecting a failure of negative feedback circuits. The IFN-gammaR deficiency did not affect the production of anti-P0 peptide 180-199-specific antibodies. These results indicate that IFN-gamma contributes to a susceptibility for EAN in C57BL/6 mice by promoting a Th1 cell-mediated immune response and suppressing a Th2 response.

Intracerebroventricular administration of somatostatin prevents and attenuates adjuvant arthritis

The effects of somatostatin on the development of adjuvant arthritis induced by Mycobacterium butyricum were studied. Somatostatin was injected into the lateral cerebral ventricle every day for 14 days beginning on the first day of mycobacteria inoculation in the preventive group. In the treatment group, somatostatin was injected from day 17 until day 30 post-mycobacteria inoculation. Arthritis was evaluated by measuring ankle joint circumference and diameter as well as microscopic examination of ankle joint sections. Somatostatin profoundly inhibited the development of adjuvant arthritis and an anti-inflammatory action was observed in the treatment group. These results suggest that somatostatin has a central action that can prevent or attenuate symptoms associated with arthritis.

CD28-B7 costimulation: a critical role for initiation and development of experimental autoimmune neuritis in C57BL/6 mice

CD28 provides a critical costimulatory signal for antigen-specific T cell activation. Because CD28 is an important factor in the development of autoimmune diseases, we investigated its role in T cell-mediated experimental autoimmune neuritis (EAN), an animal model of Guillain-Barré syndrome in humans. CD28-deficient mutant (CD28-/-) C57BL/6 mice and corresponding wild-type mice were immunized with P0 peptide 180-199, a purified component of peripheral nerve myelin, and Freund's complete adjuvant. As a result, all wild-type mice developed severe EAN, in contrast, none of the CD28-/- mice manifested clinical signs of disease. Additionally, CD28-/- mice had fewer IL-12 producing cells in sciatic nerve sections and fewer IFN-gamma secreting splenic cells than wild-type mice on day 24 post immunization, i.e., at the peak of clinical EAN. At that time point, CD28-/- mice had milder infiltration of such inflammatory cells as macrophages, CD4+ T cells and monocytes into sciatic nerve tissues and less demyelination than wild-type mice. Moreover, the CD28-deficiency led to reduced production of specific anti-P0 peptide 180-199 antibodies compared with wild-type mice. Evidently, CD28 is required for interaction with B7 to regulate the activation of T and B cells that initiates development of EAN.

Intracerebroventricular met-enkephalin administration modulates adjuvant arthritis

The purpose of this study was to investigate the anti-inflammatory properties of intracerebroventricular met-enkephalin (met-enk) administration in an animal model of arthritis. Adjuvant arthritis was induced in rats by intradermal inoculation of mycobacterium butyricum and the effects of intraventricular met-enk+thiorphan (enkephalinase inhibitor) were studied. Treatment was initiated either simultaneously with the bacterial inoculation (preventive group) or on post-inoculation day 17 after the appearance of inflammation (treatment group). The degree of inflammation was evaluated by measuring the diameter and the circumference of the ankle joint immediately before the sacrifice (day 31) and by histologic examination of ankle joint sections. The results of this study revealed that combined intraventricular injections of met-enk+thiorphan reduced the arthritic-like inflammation in the preventive group as well as in the treatment group. These findings suggest that centrally applied met-enk+thiorphan may suppress the development adjuvant arthritis as well as the symptoms of manifest arthritis. Thus central met-enk may be involved in both hypothalamic pituitary adrenal axis and immune forms of stress-induced modulation.

Safety and immunogenicity of an autoclaved Leishmania major vaccine

OBJECTIVE

To test the safety and immunogenicity of two doses of autoclaved L. major (ALM) vaccine mixed with BCG.

SETTING

Kala-azar endemic area of eastern Sudan.

DESIGN

This was a randomised, double blind and BCG controlled phase I/II study.

SUBJECTS

Eighty healthy volunteers (forty children and forty adults) with no past history of kala-azar, no reactivity to leishmanin antigen and with a reciprocal direct agglutination test (DAT) titre of <200 were recruited. Informed consents were obtained from volunteers or their guardians in case of children.

MAIN OUTCOME MEASURES

Conversion in the leishmanin skin and the DAT tests.

INTERVENTION

Two intra-dermal injections of either ALM+BCG or BCG alone. The injections were three weeks apart.

RESULTS

Side effects were minimal and confined to the injection site, with no significant difference between the ALM+BCG and the BCG alone groups. The leishmanin skin conversion was significantly higher in the ALM+BCG group compared to the BCG alone group (p<0.0005). Furthermore, the Leishmanin skin test conversion was significantly higher in children than adults (p<0.0005). One adult volunteer in the ALM+BCG group converted in both the Leishmanin skin and the DAT tests.

CONCLUSION

We conclude that two doses of ALM+BCG are safe and immunogenic, especially in children.

Neuromuscular effects of two types of fracture treatment

Immobilisation causes denervation-like changes in the motor endplates, decreases the content of IGF-I, and increases the number of IGF-I receptors in the spinal cord. In the rat we investigated whether similar changes occur after a fracture of the midshaft of the femur which had been treated by intramedullary fixation with adequate or undersized pins. A more pronounced reduction in muscle wet weight was seen after fixation by undersized pins as well as decreased ash density of the ipsilateral tibia which did not completely return to normal within the 12-week experimental period. The nicotinic cholinergic receptors in the motor endplates of tibialis anterior were increased (p < 0.01) and there was a significant increase (p < 0.02) in IGF-I receptors in the lumbar spinal cord ipsilateral to the fracture after treatment by undersized nails. These changes may be associated with the impaired proprioception, co-ordination and motor activity which are sometimes seen after fractures.

The development of post-kala-azar dermal leishmaniasis (PKDL) is associated with acquisition of Leishmania reactivity by peripheral blood mononuclear cells (PBMC)

PKDL develops in about 50% of Sudanese patients treated for visceral leishmaniasis (kala-azar). Patients with kala-azar were entered into this study and followed for a period of up to 2 years. During follow up 12 patients developed PKDL and eight did not. Proliferative responses and cytokine production to Leishmania donovani and control antigens were measured in vitro using PBMC isolated at the time of diagnosis of kala-azar, after treatment of visceral leishmaniasis, during follow up, and at the time of diagnosis of PKDL. Proliferative responses and interferon-gamma (IFN-gamma) production were low at diagnosis and increased after treatment of kala-azar in both patients who developed (group 1) and those who did not develop PKDL later (group 2). In group 1, development of PKDL was always associated by an increased PBMC response to Leishmania antigen in proliferation and IFN-gamma production assays. There were no differences in Leishmania antigen-induced production of IL-4, IL-5 and IL-10 between or within the two groups. We have previously shown that Leishmania parasites spread to the skin during visceral leishmaniasis and proposed that PKDL was the result of an immunological attack on parasites, which have survived in the skin despite the drug treatment. The finding that PKDL develops after treatment of kala-azar as Leishmania-reactive T cells start to circulate in peripheral blood in sufficient numbers to be detected in in vitro assays supports this hypothesis.

Prolactin, growth hormone, and IGF-1 in ankles and plasma of adjuvant arthritic rats

In this study we have investigated the levels of prolactin, growth hormone, and insulin-like growth factor-1 in plasma and in tissue extracts of ankle joints of rats with acute or chronic adjuvant arthritis using enzyme immunoassay (EIA) and radioimmunoassay (RIA). We found a stable content of prolactin in plasma of the different groups but a significantly increased concentration of growth hormone was observed in the plasma of the group with chronic arthritis. Moreover, an increased concentration of insulin-like growth factor-1 was noted in the plasma of the acute group. This evidently had returned to normal levels in the chronic group. In contrast, decreased concentrations of prolactin, growth hormone, and insulin-like growth factor-1 were found in tissue extracts of ankle joints of the group with chronic arthritis. The changes in the levels of these hormones in adjuvant arthritis might suggest that they play a role in the pathogenesis of the disease. Understanding the mechanism(s) of hormonal participation in adjuvant arthritis may open new treatment strategies for rheumatoid arthritis and other inflammatory disorders.

Development of a species-specific PCR-restriction fragment length polymorphism analysis procedure for identification of Madurella mycetomatis

Madurella mycetomatis is the commonest cause of eumycetoma in Sudan and other countries in tropical Africa. Currently, the early diagnosis of mycetoma is difficult. In attempting to improve the identification of M. mycetomatis and, consequently, the diagnosis of mycetoma, we have developed specific oligonucleotide primers based on the sequence of the internal transcribed spacer (ITS) regions spacing the genes encoding the fungal ribosomal RNAs. The ITS regions were amplified with universal primers and sequenced, and then two sets of species-specific primers were designed which specifically amplify parts of the ITS and the 5.8S ribosomal DNA gene. The new primers were tested for specificity with DNA isolated from human mycetoma lesions and DNA extracted from cultures of M. mycetomatis reference strains and related fungi as well as human DNA. To study the genetic variability of the ITS regions of M. mycetomatis, ITS amplicons were obtained from 25 different clinical isolates and subjected to restriction fragment length polymorphism (RFLP) analysis with CfoI, HaeIII, MspI, Sau3AI, RsaI, and SpeI restriction enzymes. RFLP analysis of the ITS region did not reveal even a single difference, indicating the homogeneity of the isolates analyzed during the current study.

Alteration of spinal cord IGF-I receptors and skeletal muscle IGF-I after hind-limb immobilization in the rat

The effects of 4 weeks' hind-limb immobilization on the spinal cord insulin-like growth factor-I (IGF-I) receptors and skeletal muscle IGF-I level was investigated in rats. Quantitative receptor autoradiography using [125I]IGF-I as a ligand was performed to measure IGF-I receptors in cryosections from the lumbar region of the spinal cord. IGF-I receptor levels were significantly higher in all spinal cord laminae on the side ipsilateral to the immobilized limb than in the same spinal level of the controls. Using radioimmunoassay (RIA), IGF-I levels were significantly low in the soleus (SOL), but not the tibialis anterior (TIB) muscles, compared to the controls. The enhancement of the spinal cord IGF-I receptors after hind-limb immobilization may constitute part of the nervous system response to disuse.

Neurokinin-A in bone and joint tissues: changes in adjuvant arthritis

The localization of neurokinin A (NK-A) in the normal ankle joint of rats was investigated by an immunoelectron microscopic technique with specific antisera to NK-A. Immunoreactivity was detected in bone matrix, myelinated nerve fiber in the periosteum, and bone marrow and synovial cells. No immunoreactivity was observed in osteoblasts, osteocytes, and osteoclasts. Using radioimmunoassay (RIA), a detectable concentration of NK-A was observed in the bone marrow, periosteum, cortical bone, and ankle of normal rats. In rats with chronic adjuvant arthritis, induced by intradermal injection of mycobacterium butyricum in paraffin oil into the base of the tail, the concentrations of NK-A using RIA in ankles and spinal cords were found to be significantly increased compared with acute or control rats. There were no significant differences between the latter two. Similarly, increased NK-A labeling was observed using immunoelectron microscopy in bone matrix and bone marrow monocyte cells of the chronic arthritic rats. These findings indicate the existence of as well as a biological role of NK-A in bone and joint tissues.

met-Enkephalin decreases in adjuvant arthritic ankles

OBJECTIVE

To study whether met-enkephalin (met-enk) concentration changes in adjuvant arthritic ankles and spinal cords.

METHODS

Adjuvant arthritis was induced by intradermal injection of Mycobacterium butyricum in paraffin oil, into the base of rat tail. The levels of met-enk were measured using radioimmunoassay and high performance liquid chromatography electrochemical detection in arthritic ankle and spinal cord of arthritic and control rats. Protein concentration was measured according to Lowry method.

RESULTS

We observed a significant decrease of concentration of met-enk in ankle joints of chronic arthritic rats. However, increased concentration of met-enk was obtained in the spinal cord of chronic arthritic rats.

CONCLUSION

The significant reduction of met-enk concentration in the arthritic ankle joints indicates a possible role for the endogenous opioid peptide in arthritis.

Somatostatin immunoreactivity in bone and joint tissues

Using immunoelectron microscopy we have investigated the presence of somatostatin in normal bone and joint tissues. We observed somatostatin labeling in the myelinated nerve fibers of the periosteum, the bone marrow cells and in the mature bone matrix but only slightly in the synovial cells. Quantification of somatostatin in bone tissue by radioimmunoassay showed highest levels in bone marrow followed by periosteum and cortical bone. These findings suggest a role for somatostatin in bone and joint physiology.

Serum erythropoietin concentration in anaemia of visceral leishmaniasis (kala-azar) before and during antimonial therapy

Serum erythropoietin (Epo) concentrations and variables of red cell and iron status were studied in 27 Sudanese patients who were treated with sodium stibogluconate for visceral leishmaniasis (kala-azar). Blood haemoglobin increased from 6.4 (+/- 1.7 SD) to 9.5 (+/- 1.4) g/dl during treatment. Serum ferritin decreased concomitantly. Serum iron levels were unchanged whereas the total iron binding capacity increased slightly. The pre-treatment serum Epo concentration in relation to the blood haemoglobin concentration was not as high as expected from the one in primary haematological diseases, indicating that there is a relative lack of Epo in anaemic kala-azar patients. Serum Epo further decreased during stibogluconate therapy. The normal dependence of the serum Epo level on the blood haemoglobin concentration was lost during mid-term antimonial treatment, but it recovered thereafter. Cell culture studies with the human hepatoma cells HepG2 showed that stibogluconate (> or = 30 microg/ml) inhibited Epo gene expression. Thus, effective treatment of kala-azar with stibogluconate results in improvement of anaemia, although the drug itself may impair Epo production.

Antibody reactivity to conserved linear epitopes of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1)

The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family of protein antigens are involved in adhesion of P. falciparum infected erythrocytes to the capillary endothelium of the host. Antibodies to variable regions of these proteins, measured by agglutination, correlates with clinical protection against falciparum malaria. In this study we investigated the occurrence of antibodies to conserved sequences of these very variable proteins in a population living in an area endemic for falciparum malaria. Using the ELISA method, we were able to measure an antibody response to three synthetic peptides derived from conserved regions of PfEMP1. The antibody responses to these peptides increased with age and were higher in individuals with asymptomatic P. falciparum infection compared to individuals presenting with fever attributable to falciparum malaria. This indicates that antibodies recognising the conserved regions of PfEMP1 arise upon exposure to the parasite, and that these may be involved in the development of protection against malaria. Antibodies to the Pfalhesin peptide of the human aniontransporter, band3, were measured by the same method. The magnitude of this antibody response did not correlate with neither age nor clinical protection.

High levels of plasma IL-10 and expression of IL-10 by keratinocytes during visceral leishmaniasis predict subsequent development of post-kala-azar dermal leishmaniasis

Some patients develop post-kala-azar dermal leishmaniasis (PKDL) after they have been treated for the systemic infection kala-azar (visceral leishmaniasis). It has been an enigma why the parasites cause skin symptoms after the patients have been successfully treated for the systemic disease. We report here that PKDL development can be predicted before treatment of visceral leishmaniasis, and that IL-10 is involved in the pathogenesis. Before treatment of visceral leishmaniasis, Leishmania parasites were present in skin which appeared normal on all patients. However, IL-10 was detected in the keratinocytes and/or sweat glands of all patients who later developed PKDL (group 1) and not in any of the patients who did not develop PKDL (group 2). Furthermore, the levels of IL-10 in plasma as well as in peripheral blood mononuclear cell culture supernatants were higher in group 1 than in group 2.

Methionine-enkephalin in bone and joint tissues

Methionine-enkephalin (met-enk), an endogenous opiate, mimics many of the effects of morphine by binding to opiate receptors, thereby eliciting similar cellular and behavioral effects. Using biochemical and immunohistochemical techniques, several peptides have been identified in bone and joint tissues. Here we report, for the first time, the presence as well as concentration of met-enk in bone and joint tissues. Immunohistochemistry using electron and immunofluorescence microscopy showed cellular and neuronal distribution of met-enk in bone and joint tissues. The concentration of met-enk analyzed by high performance liquid chromatography electrochemical detection or radioimmunoassay was high in bone marrow, periosteum, ankle joint tissue, and cortical bone. Analysis by fast atom bombardment mass spectrometry suggested that the recovered fragment was met-enk Administration of met-enk inhibits osteoblast cell growth in culture, which is reversible by naltrexone. In arthritic rats, the concentration of met-enk was significantly decreased in ankle joints compared with controls, suggesting a role for met-enk in the pathophysiology of adjuvant arthritis.

Diagnosis of visceral leishmaniasis by the polymerase chain reaction using blood, bone marrow and lymph node samples from patients from the Sudan

We have evaluated the sensitivity of the polymerase chain reaction (PCR) as a diagnostic tool for Leishmania donovani using blood, bone marrow and lymph node samples from Sudanese patients with a confirmed infection. Forty patients were diagnosed by microscopic examination of bone marrow or lymph node samples. The PCR was able to detect parasite DNA in 37 out of 40 blood samples. In bone marrow and lymph node samples, the PCR was able to detect parasite DNA in all 7 and 6 samples, respectively. We suggest that the PCR should be considered as a valuable and sensitive tool for the diagnosis of L. donovani infection. However, if PCR diagnosis is to supplement or even replace microscopic diagnosis in developing countries, a large number of patients with no apparent signs of infection and patients with other diseases have to be tested in order to evaluate its true potential.

Tinea versicolor and visceral leishmaniasis

BACKGROUND

Visceral leishmaniasis (VL) is endemic in several areas in the Sudan. The disease is associated with depressed cellular immunity. Tinea versicolor is a normal commensal of the skin which can become pathogenic particularly in patients with depressed cell-mediated immunity. Patients with VL have a high prevalence of tinea versicolor.

METHODS

One hundred and thirty patients with parasitologic confirmation of VL were screened for tinea versicolor infection. In the suspected cases the diagnosis was made by demonstrating the fungal hyphae and spores in skin scrapings. All patients were treated with sodium stibogluconate.

RESULTS

Of the 130 patients with VL, 10.8% were found to have severe tinea versicolor. The fungal infection developed or became worse with the start of VL. After successful treatment of VL, the tinea lesions disappeared completely or decreased in severity.

CONCLUSIONS

Depressed cell-mediated immunity that is a feature of VL is the probable underlying cause for fungal infection. Tinea infection during the course of VL is to be distinguished from lesions of post-kala-azar dermal leishmaniasis.

Post-kala-azar dermal leishmaniasis in the Sudan: peripheral neural involvement

Four patients developed post-kala-azar dermal leishmaniasis and neuritis (PKDL) 1 to 6 months following apparently successful treatment of kala-azar. The duration of the lesion varied between 1 month and nearly 5 years. The lesions were macules, papules, or nodules affecting the face, extremities, and trunk. The diagnosis was made by demonstration of the parasite in slit smear and biopsies and by a positive direct agglutination test (DAT). Histologically, the patients were found to have neuritis affecting the cutaneous nerves in the lesion only. The nerves showed a lymphohistiocytic infiltration and occasionally parasites. There was no impairment of sensation. Response to sodium stibogluconate was good. PKDL may simulate leprosy both clinically and pathologically.