The effect of particle size and electrical charge on macrophage-osteoclast differentiation and bone resorption

In aseptic loosening, there is commonly periprosthetic bone loss and a heavy macrophage infiltrate in response to biomaterial wear particles generated from the implant materials. Macrophages which have phagocytosed wear particles are known to be capable of differentiation into bone resorbing osteoclasts. In this investigation we determine the role of particle size and particle charge on this process. Mouse monocytes and macrophages were co-cultured with osteoblast-like UMR106 cells and 1,25 dihydroxyvitamin D3 in the presence or the absence of (i) various sizes of latex beads (0.1, 1, 10 and 100 microm) and (ii) uncharged, positively- or negatively-charged sephadex beads of uniform shape and composition. The extent of osteoclast differentiation by monocytes or foreign body macrophages was determined by the expression of the osteoclast-associated enzyme tartrate-resistant acid phosphatase and lacunar bone resorption. No significant difference in the extent of osteoclast formation and bone resorption was noted in response to particle size. Osteoclast formation was also not significantly different in the presence of positively/negatively charged and uncharged particles. These findings indicate that osteoclast formation is not significantly influenced by particle characteristics, such as particle size. They also add support to the hypothesis that macrophage involvement in periprosthetic osteolysis is not dependent on particle phagocytosis and that it may be induced by particle contact.

Occult hepatitis B virus infection as a cause of cirrhosis of liver in a region with intermediate endemicity

BACKGROUND

Serological tests may fail to identify hepatitis B virus (HBV) infection as a cause of liver cirrhosis in a proportion of patients. The frequency of such occult infection in regions with intermediate HBV endemicity is not known. Such cases may be diagnosed by incremental testing for IgG anti-HBc, serum HBV DNA, and HBV DNA in liver tissue.

METHODS

We tested sera of 111 patients with cirrhosis, including 39 with history of significant alcohol ingestion, for HBsAg, anti-HBc and serum HBV DNA. In addition, in a subset of 14 patients, HBV DNA was looked for in liver tissue.

RESULTS

On HBsAg and anti-HBc testing, 66 patients had HBV infection. Serum HBV DNA testing identified HBV infection in 13 additional cases. Of 18 patients labeled as 'cryptogenic' on serological testing, HBV DNA was detected in the serum in 7 patients. Of 14 patients in whom paired liver tissue and serum specimens were tested, 4 additional patients with HBV infection were detected after liver biopsy analysis.

CONCLUSIONS

Serological tests for HBsAg and anti-HBc antibody are insensitive in identifying HBV infection in patients with liver cirrhosis. HBV DNA testing in serum and liver can help in establishing HBV infection as etiology, either alone or in addition to another cause.

Inhibition of anti-CD3 and interleukin-2 stimulated T lymphocyte proliferation by peptidomimetic opioid compound

In continuation to our earlier studies with peptidomimetic opioid compounds, we have further investigated immunosuppressive properties of one of our peptidomimetic compound (Tyr-NH-CH2-CH2-O-Phe-NH2) using peripheral blood mononuclear cells (PBMCs) of healthy volunteers. Peptidomimetic compound was evaluated for its effect on anti-CD3 and recombinant human interleukin-2 (rhIL-2) stimulated lymphocyte proliferation in vitro and lipopolysaccharide (LPS) induced activation of mitogen activated protein kinase (MAPK, pp42/44) in mouse macrophage cells (RAW 264.7). Our results show the immunosuppressive potential of synthetic peptidomimetic compound. This compound significantly inhibited anti-CD3 and rhIL-2 stimulated lymphocyte proliferation in vitro. However, this peptidomimetic compound did not show any effect on LPS induced MAPK activation. These observations suggest that above peptidomimetic compound has potential to inhibit immune responses mediated by lymphocytes.

Anticellular and immunosuppressive properties of ethanolic extract of Acorus calamus rhizome

Modulation of immune response to alleviate disease has been of interest since long. Plant extracts have been widely investigated for possible immunomodulatory properties. We have evaluated the anticellular and immunomodulatory properties of ethanolic extract of Acorus calamus rhizome. This extract inhibited proliferation of mitogen (phytohaemagglutinin; PHA) and antigen (purified protein derivative; PPD)-stimulated human peripheral blood mononuclear cells (PBMCs). In addition, A. calamus extract inhibited growth of several cell lines of mouse and human origin. It also inhibited production of nitric oxide (NO), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha). Intracytoplasmic interferon-gamma (IFN-gamma) and expression of cell surface markers, CD16 and HLA-DR, on human PBMC, were not affected on treatment with A. calamus extract but CD25 expression was down regulated. Our study demonstrates the antiproliferative and immunosuppressive potential of ethanolic extract of A. calamus rhizome in vitro.

Purification and characterization of a lectin from wild sunflower (Helianthus tuberosus L.) tubers

A lectin (HTTL) was isolated from Helianthus tuberosus L. (wild sunflower) tubers using ion-exchange chromatography, gel filtration, and affinity chromatography. The lectin agglutinated both untreated and trypsin-treated rabbit erythrocytes and did not agglutinate human blood cells of groups A, B, and O. The gel filtration showed the native molecular mass of 72 kDa and subunit molecular masses of 17 and 18.5 kDa on 12% SDS-PAGE. The lectin activity was inhibited by D-mannose. The tetrameric protein revealed a unique characteristic by forming a broad zone of protein in native PAGE at pH 8.3, which dissociated into seven subunits of varying e/m ratios on acid gel at pH 4.3. These seven bands revealed two polypeptide species of molecular masses 17 and 18.5 kDa on 12% SDS-PAGE, as in the case of the native protein. The result indicated that of the seven subunits, three were homotetramers of 17 kDa, one was a homotetramer of 18.5 kDa, and three were heterotetramers of 17 and 18.5 kDa. The lectin was thermostable with broad pH optima (pH 4-8) and had no requirement for divalent metal cations for its activity. The amino acid composition showed that the lectin contained higher amounts of glycine, alanine, and lysine, but no methionine. The sugar content was estimated to be 5.3% mannose equivalent. The HTTL was mitogenic to mouse spleen (total) cells at 25 microg/ml concentration. The lectin showed characteristics different from those of the earlier reported H. tuberosus tuber lectins and hence opens up a new avenue to investigate the structure-function relationship of lectin in Helianthus species.

Evaluation of UV-radiation induced singlet oxygen generation potential of selected drugs

Photosensitization reaction of drugs leading to the formation of reactive oxygen species under ultraviolet radiation (UVR) can cause tissue injury, resulting in damage to various cellular macromolecules. The aim of this study was to determine the singlet oxygen generation potential of some commonly used antibiotics so that due precautions can be exercised to minimize their photosensitizing action and oxidative stress potential. The selected antibiotics were examined for their ability to produce singlet oxygen (1O2) under artificial UVA (320-400 nm). Singlet oxygen generation of various screened antibiotics under UVA is of the following order: Nalidixic acid > Amphotericin-B > Cephradine > Cefazolin > Nafcillin > Cephalothin > Ampicillin > Cephalexin > Puromycin > Kanamycin > Lincomycin > Tetracycline > Nystatin > Gentamicin sulphate. Nalidixic acid, the most potent generator of 1O2 among the screened antibiotics, was selected to carry out further studies. Certain specific quenchers of 1O2 such as beta-carotene, 1,4-diazabicyclo[2.2.2] octane (DABCO), and sodium azide (NaN3) accorded significant inhibition in the production of 1O2. The results suggest that precautions are necessary to avoid ultraviolet radiation after the intake of photoreactive drugs, especially in tropical countries such as India. These findings are significant because UVB radiation is reportedly increasing on earth surface in part due to depletion of stratospheric ozone layer. The selected drugs are commonly used for the treatment of various diseases. Thus, the synergistic action of both can lead to undesirable phototoxic responses.

Sickle cell morbidity profile in Omani children

In order to define the morbidity profile of sickle cell disease in Omani children, we analysed data on 97 children (53 boys, 44 girls) aged < or = 12 years admitted under our care in a regional referral hospital between July 1999 and June 2000. Ninety of them had sickle cell anaemia (HbSS disease) and seven had sickle cell thalassaemia (beta zero). Their mean (SD) steady-state Hb was 7.9 (1.2), range 6-10 g/dl. They were admitted on 316 occasions during the 12-month period. The number of admissions per child ranged from one to 12 (mean 3.3). Vaso-occlusive crises were the main reason for admission (83%), followed by severe anaemia (12%) and infections (4%). During the study period, 31% received blood transfusions. Weight faltering was very common, 68% falling below the 5th percentile of the National Center for Health Statistics reference curves compared with 28% of age- and sex-matched non-sicklers (p < 0.001). Other complications included hypersplenism (four), ischaemic necrosis of the femoral head (two), and one case each of acute chest syndrome, acute splenic sequestration, cholelithiasis and pathological fracture of a lumbar vertebra. Overall, 71% of the children had moderately severe or severe disease. This pattern seems to be attributable, at least in part, to meteorological and genetic factors. The severe morbidity profile reported in this study underscores the need to continue the search for optimal management modalities, including the often emotion-laden issue of prevention.

Hydroxyapatite particles are capable of inducing osteoclast formation

Hydroxyapatite (HA) coatings have been used to improve implant fixation by promoting bone formation around the prosthesis. A macrophage response to HA particulates has been noted around loosened HA-coated prostheses. As biomaterial wear particle-associated macrophages are known to be capable of differentiating into osteoclasts that are capable of bone resorption, we examined whether particulate HA could similarly induce macrophage-osteoclast differentiation. HA-associated macrophages were isolated from granulomas, formed by subcutaneous implantation of HA, and co-cultured with UMR 106 osteoblast-like cells in the presence of 1,25-dihydroxyvitamin D(3) for up to 14 days on glass coverslips and bone slices. HA-associated macrophage-osteoclast differentiation was evidenced by the formation of numerous multinucleated tartrate resistant acid phosphatase (TRAP)-positive cells which formed lacunar resorption pits on bone slices. Polymethylmethacrylate (PMMA) particle-associated macrophages, isolated from subcutaneous PMMA-containing granulomas, caused significantly more osteoclast formation and bone resorption than HA-associated macrophages. These results indicate that macrophages responding to HA particles are capable of osteoclast differentiation. They also suggest that particles derived from uncemented (HA-coated) implants are likely to induce less osteoclast formation and osteolysis than cemented implants.

Histological and microbiological findings in non-infected and infected revision arthroplasty tissues. The OSIRIS Collaborative Study Group. Oxford Skeletal Infection Research and Intervention Service

An assessment of clinical and laboratory findings is generally required to distinguish between septic and aseptic loosening of a hip implant. In order to evaluate the diagnostic utility of histological and microbiological investigative techniques to differentiate between these two conditions, we analysed their results in 617 patients with hip implant loosening. Histology and microbiology study confirmed the clinical diagnosis of septic loosening in approximately 98% and 89%. respectively. The clinical diagnosis of aseptic loosening was confirmed by histology in 99% of cases. In all but 2 of 81 cases of septic loosening, in which an organism was isolated on microbiological culture, the histological diagnosis of septic loosening was made on the basis of the degree of the acute inflammatory infiltrate (i.e. the presence of 1 or more neutrophil polymorphs per high power field (x 400) on average after examination of at least 10 high power fields) in periprosthetic tissues. In 10 patients for whom there was a strong clinical suspicion of septic loosening but no organisms were isolated on microbiological culture, the histological findings, using the above criteria, were in keeping with the clinical diagnosis of septic loosening. As almost 11% of cases of septic loosening would not have been diagnosed by microbiological investigation alone, our findings indicate that histological examination of periprosthetic tissues should form part of the investigative protocol to distinguish between aseptic and septic loosening.

Electronic structure and properties of transition metal-benzene complexes

A comprehensive theoretical study of the geometries, energetics, and electronic structure of neutral and charged 3d transition metal atoms (M) interacting with benzene molecules (Bz) is carried out using density functional theory and generalized gradient approximation for the exchange-correlation potential. The variation of the metal-benzene distances, dissociation energies, ionization potentials, electron affinities, and spin multiplicities across the 3d series in MBz complexes differs qualitatively from those in M(Bz)(2). For example, the stability of Cr(Bz)(2) is enhanced over that of CrBz by almost a factor of 30. On the other hand, the magnetic moment of Cr(Bz)(2) is completely quenched although CrBz has the highest magnetic moment, namely 6 mu(B), in the 3d metal-benzene series. In multidecker complexes involving V(2)(Bz)(3) and Fe(2)(Bz)(3), the metal atoms are found to couple antiferromagnetically. In addition, their dissociation energies and ionization potentials are reduced from those in corresponding M(Bz)(2) complexes. All of these results agree well with available experimental data and demonstrate the important role the organic support can play on the properties of metal atoms/clusters.

Clinical profile and prognosis of Addison's disease in India

BACKGROUND

The clinical presentation of primary adrenocortical insufficiency (Addison's disease) in India may differ from that in developed countries. We therefore studied the clinical profile and prognosis of Addison's disease, with special reference to patients with tuberculous infection. We also evaluated the utility of various clinical parameters in differentiating tuberculous from idiopathic Addison's disease.

METHODS

In a retrospective and prospective study, 45 consecutive patients of Addison's disease (20 patients with tuberculous aetiology) were studied for their clinical features, autoantibody profile (adrenal cytoplasmic, thyroid microsomal and gastric parietal cell antibodies) and prognosis.

RESULTS

A tuberculous aetiology was present in 47% of the patients and of these, 85% had enlargement of one or both adrenal glands. While patients with tuberculous Addison's disease had a higher prevalence of extra-adrenal tuberculosis (55% v. 9%, p = 0.001), a lower frequency of adrenal cytoplasmic antibodies (17% v. 50%, p = 0.03) and parietal cell or thyroid microsomal antibodies (11% v. 55%, p = 0.004), a considerable overlap was observed. Despite adverse circumstances, during a mean follow up of 3.3 years, only 2 (5%) patients died, neither of whom had tuberculous involvement. Five (13%) patients suffered from one or more episodes of Addisonian crises, though none of these resulted in mortality.

CONCLUSION

Tuberculosis remains an important cause of Addison's disease in India. The presence of extra-adrenal tuberculosis, or lack of adrenal cytoplasmic antibodies, does not, with certainty, differentiate between a tuberculous and idiopathic aetiology. The prognosis of Addison's disease was good despite unfavourable circumstances.

Seminal toxicity of nickel sulfate in mice

Young male albino mice of Swiss strain were exposed to nickel by oral route of 20 mg nickel sulfate/kg body weight for 5 d/wk for 6 mo. A decrease in normal (testosterone-dependent) proteinuria was shown, and morphological examination of the seminal vesicles revealed a lower weight and smaller size as well as a histological indication of lower secretory activity of the epithelium compared to controls. The findings are consistent with a theory implying a decreased testosterone activity in nickel-treated animals.

Pharmacokinetics of ICG and HPPH-car for the detection of normal and tumor tissue using fluorescence, near-infrared reflectance imaging: a case study

We present in vivo fluorescent, near-infrared (NIR), reflectance images of indocyanine green (ICG) and carotene-conjugated 2-devinyl-2-(1-hexyloxyethyl) pyropheophorbide (HPPH-car) to discriminate spontaneous canine adenocarcinoma from normal mammary tissue. Following intravenous administration of 1.0 mg kg-1 ICG or 0.3 mg kg-1 HPPH-car into the canine, a 25 mW, 778 nm or 70 mW, 660 nm laser diode beam, expanded by a diverging lens to approximately 4 cm in diameter, illuminated the surface of the mammary tissue. Successfully propagating to the tissue surface, ICG or HPPH-car fluorescence generated from within the tissue was collected by an image-intensified, charge-coupled device camera fitted with an 830 or 710 nm bandpass interference filter. Upon collecting time-dependent fluorescence images at the tissue surface overlying both normal and diseased tissue volumes, and fitting these images to a pharmacokinetic model describing the uptake (wash-in) and release (wash-out) of fluorescent dye, the pharmacokinetics of fluorescent dye was spatially determined. Mapping the fluorescence intensity owing to ICG indicates that the dye acts as a blood pool or blood persistent agent, for the model parameters show no difference in the ICG uptake rates between normal and diseased tissue regions. The wash-out of ICG was delayed for up to 72 h after intravenous injection in tissue volumes associated with disease, because ICG fluorescence was still detected in the diseased tissue 72 h after injection. In contrast, HPPH-car pharmacokinetics illustrated active uptake into diseased tissues, perhaps owing to the overexpression of LDL receptors associated with the malignant cells. HPPH-car fluorescence was not discernable after 24 h. This work illustrates the ability to monitor the pharmacokinetic delivery of NIR fluorescent dyes within tissue volumes as great as 0.5-1 cm from the tissue surface in order to differentiate normal from diseased tissue volumes on the basis of parameters obtained from the pharmacokinetic models.

Sweet's syndrome and Pneumocystis carinii pneumonia: two sequelae of low-dose cytosine arabinoside therapy in a patient with acute myeloid leukemia

Cytosine arabinoside in low dose is sometimes employed for treating acute myeloid leukaemia. We report here a case of acute myeloid leukemia, treated with low-dose cytosine arabinoside, who developed acute febrile neutrophilic dermatosis and Pneumocystis carinii pneumonia after attainment of remission. A direct effect of cytosine arabinoside on neutrophil function and an immunosuppressive potential in lower doses could be speculated.

Fine needle aspiration cytology in xanthogranulomatous cholecystitis, gallbladder adenocarcinoma and coexistent lesions

OBJECTIVE

To evaluate the diagnostic efficacy of fine needle aspiration cytology (FNAC) in gallbladder mass lesions and to explore the possibility of overlooking malignancy in coexistent adenocarcinoma with xanthogranulomatous cholecystitis (XGC) on fine needle aspiration smears.

STUDY DESIGN

In a retrospective, seven-year study, ultrasound-guided needle aspirates from 25 histologically proven cases of gallbladder adenocarcinoma, 11 cases of gallbladder adenocarcinoma associated with XGC and 20 cases of XGC were evaluated for the presence of mesotheliumlike, foam, inflammatory and multinucleate giant cells; pink, granular background; bile; and degenerated cells, along with atypical or frankly malignant cells. Detailed clinical findings were retrieved from the records.

RESULTS

The overall sensitivity of detecting carcinoma was 90.63% and specificity 94.74%. The sensitivity of detecting malignancy was 80% when adenocarcinoma was associated with XGC.

CONCLUSION

FNAC plays an important role in making the preoperative diagnosis of adenocarcinoma, XGC and coexistent lesions. The probability of detecting malignancy is greater than with XGC in coexistent lesions. Thus, a preoperative FNAC diagnosis would help in determining the urgency of treatment and in planning for the surgical procedure in gallbladder lesions.

Pharmacokinetics of ICG and HPPH-car for the detection of normal and tumor tissue using fluorescence, near-infrared reflectance imaging: a case study

We present in vivo fluorescent, near-infrared (NIR), reflectance images of indocyanine green (ICG) and carotene-conjugated 2-devinyl-2-(1-hexyloxyethyl) pyropheophorbide (HPPH-car) to discriminate spontaneous canine adenocarcinoma from normal mammary tissue. Following intravenous administration of 1.0 mg kg-1 ICG or 0.3 mg kg-1 HPPH-car into the canine, a 25 mW, 778 nm or 70 mW, 660 nm laser diode beam, expanded by a diverging lens to approximately 4 cm in diameter, illuminated the surface of the mammary tissue. Successfully propagating to the tissue surface, ICG or HPPH-car fluorescence generated from within the tissue was collected by an image-intensified, charge-coupled device camera fitted with an 830 or 710 nm bandpass interference filter. Upon collecting time-dependent fluorescence images at the tissue surface overlying both normal and diseased tissue volumes, and fitting these images to a pharmacokinetic model describing the uptake (wash-in) and release (wash-out) of fluorescent dye, the pharmacokinetics of fluorescent dye was spatially determined. Mapping the fluorescence intensity owing to ICG indicates that the dye acts as a blood pool or blood persistent agent, for the model parameters show no difference in the ICG uptake rates between normal and diseased tissue regions. The wash-out of ICG was delayed for up to 72 h after intravenous injection in tissue volumes associated with disease, because ICG fluorescence was still detected in the diseased tissue 72 h after injection. In contrast, HPPH-car pharmacokinetics illustrated active uptake into diseased tissues, perhaps owing to the overexpression of LDL receptors associated with the malignant cells. HPPH-car fluorescence was not discernable after 24 h. This work illustrates the ability to monitor the pharmacokinetic delivery of NIR fluorescent dyes within tissue volumes as great as 0.5-1 cm from the tissue surface in order to differentiate normal from diseased tissue volumes on the basis of parameters obtained from the pharmacokinetic models.

Extradural meningioma en-plaque of the cervical cord

A rare case of cervical extradural en-plaque meningothelial meningioma is reported. The magnetic resonance imaging revealed an extradural sheet of tumor encasing the cervical cord from anterior, posterior and right lateral aspects and emerging from the right C3-4 intervertebral foramina. Though a differential diagnosis of lymphoma and tubercular granulation tissue were considered, its isointense intensity patterns on T1 and T2 weighted images and the intratumoral calcification on intrathecal contrast computed tomographic scan suggested a meningioma. At surgery, the lesion was fibrous, avascular and densely adherent to the dura. The radiological features and management options of the lesion are discussed.

Spectral light quality affects protein profile of Synechococcus sp. PCC 7942: a comparative 2-dimensional gel electrophoresis (2-DGE) analysis

We report here a comparative analysis of the effect of blue (450 nm), red (660 nm), and white light (400-700 nm) on the protein profile of cyanobacteria Synechococcus sp. PCC 7942. In vivo labeling of cells with [(35)S] methionine and their subsequent analysis by two-dimensional gel electrophoresis (2-DGE) showed that eight polypeptides were unique to dark adapted cells, ten were blue light specific, and four were specifically induced in red light. The results show that Synechococcus sp. respond to various light treatments rapidly and synthesize new polypeptides in dark and blue/red light.