Short-term outcome of acute inferior wall myocardial infarction with emphasis on conduction blocks: a prospective observational study in Indian population

OBJECTIVE

The primary aim of the present study was to evaluate the complications, particularly conduction blocks, subsequent morbidity and mortality, and effect of thrombolytic therapy in Indian patients with inferior wall myocardial infarction (IWMI).

METHODS

This was a prospective, observational, single-center study conducted at LPS Institute of Cardiology, Kanpur, from December 2011 to May 2014. Patients who presented with typical chest pain and were subsequently diagnosed by standardized diagnostic criteria as having IWMI were enrolled. Patients were grouped on basis of conduction abnormalities, right ventricular (RV) infarction and thrombolytic treatment. Each group was analyzed for comparison of complication profile and mortality.

RESULTS

Of 573 patients with IWMI enrolled in the study (mean age: 58.90±12.3 years), 81.2% were male, 225 (39.3%) had conduction blocks, and 189 (32.9%) had RV infarction. In patients with conduction blocks, mortality occurred in 27 patients (12.0%) in contrast to 3.4% of patients without conduction block (p<0.03). Also, there were 27 cases of in-hospital mortality in patients with RV infarction compared with 9 cases in patients without RV infarction (p<0.01). Thrombolytic therapy significantly reduced mortality in patients with IWMI (p<0.001). A significant reduction was observed in cardiogenic shock (p=0.002), severe mitral regurgitation (p=0.007), and left ventricular failure (p<0.001) in patients undergoing thrombolytic therapy.

CONCLUSION

In Indian patients with IWMI, incidence of conduction blocks was higher than previously reported studies. Major complications such as atrioventricular block and RV infarction are associated with increased mortality and poor clinical outcomes. Thrombolytic therapy has a beneficial role in reduction of mortality rate and other complications.

Effect of Oral Vitamin E on Oxy-Free Radical Status in Acute Myocardial Infarction

The present work was conducted to study the status of oxidative stress (oxy-free radicals) in 24 patients with acute myocardial infarction and 12 matched healthy control patients and furthermore evaluate the effect of oral vitamin E on altered oxyfree radicals in these patients. The parameters assessed for oxy-free radical status were superoxide anion and malonyldialdehyde. These were found to be increased during acute myocardial infarction and this increment had a normalizing trend with the passage of time. It was found that the administration of vitamin E accelerated the normalizing trend of both superoxide anion and malonyldialdehyde. Thus, vitamin E has an antioxidant effect in acute myocardial infarction.

[Pathology of implants]

Progress in the surgery of implants and biomaterials can be accomplished by: 1. Painstakingly analysing and registering of defaulting implants after explantation within a "National Registry of Implant Pathology". 2. Development of a DNA-microarray named "Implantat/Chronic Wound" in order to discover the differential transcriptional activities of cells brought into contact with different foreign surfaces. 3. Predictive cell-engineering combined with custom-made implant surfaces with the aim of optimal patient care.

Individual inflammatory response of human blood monocytes to mesh biomaterials

BACKGROUND

Alloplastic implants such as those employed in hernia repair induce distinct local inflammation and seroma production. As monocytes take a key position in the inflammatory foreign body reaction, their specific release of cytokines was investigated in vitro after incubation with alloplastic materials.

METHODS

Human blood monocytes were isolated from buffy coats of 42 healthy blood donors. Cells were cultivated in polystyrene culture wells (4 x 10(6) cells/well) on polypropylene-polyglactin mesh, on polytetrafluoroethylene, in control wells with the addition of 1 micro g lipopolysaccharide (LPS) and on pure polystyrene. Supernatant was taken after 1 h and 5 days, and concentrations of tumour necrosis factor (TNF) alpha, interleukin (IL) 6 and IL-10 were determined. Donors were defined as 'high' or 'low' responders when concentrations of TNF-alpha were above the 75th or below the 25th percentiles, respectively.

RESULTS

In contact with biomaterials, the monocytes liberated TNF-alpha, IL-6 and IL-10, similar to levels observed after stimulation with LPS. Median cytokine concentrations were not normally distributed and were influenced by donor, timepoint and applied stimulus. One donor matched the criteria for low responder and three for high responder.

CONCLUSION

The individual was identified as an independent factor for the inflammatory response of monocytes to biomaterials. Moreover, high and low responders could be identified. The variability of cytokine release and the lack of a normal distribution suggest that a larger sample size should be used in future studies of cellular response.

Monitoring of presterile disposable syringes and needles marketed in Pune

Out of hundred syringes and hundred needles (both presterile, disposable) tested, 41 syringes (41%) and 6 needles (6%) showed aerobic growth. Forty of the above syringes were tested simultaneously for fungi and anaerobes. Fungi isolated were 5.7% and no anaerobe was grown. Fifty glass syringes and fifty needles autoclaved in the departmental laboratory served as controls and did not show any growth. As a preventive measure, proper disposal of used disposable material should be made mandatory so that it does not find its way into the market. Or has the time come to switch back to the former conventional practice of using in house autoclaved articles?

Role of HSP70i in regulation of biomaterial-induced activation of human monocytes-derived macrophages in culture

The functioning of an implant depends on the material properties and the wound-healing process. The latter is led by an inflammatory reaction guided mainly by monocyte/macrophage activity. This in vitro study investigated human monocytes/macrophages in culture from 2 h to 10 days on silicone, polyurethane, teflon and TCPS. Analysis of cytokine release by ELISA showed that maturing macrophages have different capacities to produce cytokines TNFalpha, IL10, IL8 and GM-CSF. The long culture-mature macrophages on all polymers produced comparable low levels of TNFalpha, IL10 and IL8. Monocytes/macrophages on polyurethane and teflon, and those on silicone only in long culture-time produced high GM-CSF amounts, where as those on TCPS exhibited low levels of GM-CSF. FACS analysis revealed that HSP70i was highly inducible after short time culture yet this high level was maintained in long culture-mature macrophages on TCPS only, whereas on other polymers the mature macrophages showed a high reduction in HSP70i level, which demonstrated a high stress-response by cells on TCPS. Accordingly, CLSM-analysis revealed low nuclear NF-kappaB in cells on TCPS and high nuclear NF-kappaB in mature macrophages on silicone and polyurethane, showing a high cellular activation on the latter two polymers. This corresponded also to the high mitochondrial activity by XTT metabolism displayed by the mature macrophages on polyurethane >/= silicone > teflon > TCPS. These data show a correlation of (1) cytokines (TNFalpha, GM-CSF) and HSP70i, (2) NF-kappaB and HSP70i by monocytes/macrophages after contact with polymers. Thus, HSP70i might be a useful molecular candidate for exploring biomaterial-induced inflammatory reaction.

Collagen I/III and matrix metalloproteinases (MMP) 1 and 13 in the fascia of patients with incisional hernias

The late appearance ofincisional hernias several years after laparotomy and the high recurrence rates after operation strongly imply the presence of a disorder of the connective tissue, although a specific defect in patients with incisional hernias has not yet been identified. In the present study we used both immunohistochemistry and Western blot analysis to evaluate the ratio of collagen I and III and the expression of the metalloproteinases (MMP) 1 and 13 in the fascia of patients with incisional or recurrent incisional hernias. Samples of healthy skin or stable skin scar in patients without hernias served as controls. Altogether, our data indicated a significantly decreased ratio of collagen I/III in the fascia of patients with incisional hernias and recurrent incisional hernias. Furthermore, in these patients the expression of MMP-1 was decreased compared to the controls, whereas MMP-13 could not be detected in any fascia sample, with or without hernias present. For the first time, our results give evidence of the existence of a possible collagen disorder in these patients. The decreased ratio ofcollagen I/III is explainable due to a relative increase of collagen type III, which is known to be characterized by thin fibril diameters and lowered mechanical strength. The altered collagen ratio might be the result of the decreased activity of MMP-1, whereas the absent MMP-13 expression did not seem to modify the scar formation. Thus, our data indicate the presence of collagen metabolic disorders in patients with incisional hernias and recurrent incisional hernias. Furthermore, these results might explain the poor results of a mesh-free hernia repair, which again builds up scar tissue of inadequate collagen composition and strength.

Expression of the extracellular matrix proteins collagen I, collagen III and fibronectin and matrix metalloproteinase-1 and -13 in the skin of patients with inguinal hernia

Although abnormal collagen metabolism has been ascribed an important role in the high recurrence rates after surgical hernia repair, knowledge on tissue sampled in the region affected by inguinal hernias is poor. In the present study, we determined collagen type I and type III in the skin of adult patients with indirect and direct inguinal hernias by both immunohistochemistry and Western blot analysis. In addition, we quantified the immunohistochemical expression of fibronectin and matrix metalloproteinase (MMP)-1 and -13. The results indicated that the ratio of collagen type I/III was significantly decreased in the skin of patients with either indirect (n = 9) or direct hernia (n = 7), with a concomitant increase in collagen type III (p < 0.001 vs. controls, n = 7, without affection of the inguinal region). There was no significant difference between patients with indirect and direct hernia (p > 0.05). MMP-13 was not expressed in any of the skin samples investigated, whereas MMP-1 was found in the epidermis. Fibronectin was predominantly detected at the epidermal-dermal junction. MMP-1, MMP-13 and fibronectin levels were significantly different between patients and controls (p > 0. 05). We conclude that in contrast to the unchanged expression of fibronectin and MMP-1 and MMP-13, the decreased ratios of collagen tpye I/III with the basically increased amount of collagen type III could be of significant importance for the pathophysiology of hernias. The specific ratio collagen I/III probably reflects the altered structural integrity and mechanical stability of the connective tissue in both indirect and direct hernias. Moreover, our findings stress that hernias should be regarded as the manifestation of a systemic disease in the inguinal region with a genetic background, explaining the high recurrence rates after repeated suture repair, as well as the usefulness of surgical meshes in this clinical setting.

Abnormal collagen I to III distribution in the skin of patients with incisional hernia

The surgical mesh-free repair of incisional hernias has to face recurrence rates of up to 50%. Apart from technical faults this is probably due to collagen metabolic disorders, known to play an important role in the development of inguinal hernia. In particular an altered ratio of collagen types I and III with an increase in collagen type III has been claimed to reduce the mechanical strength of connective tissues. Therefore, we investigated the content of collagen types I and III in the skin of patients with incisional hernia (n = 7) and recurrent incisional hernia (n = 5) in comparison to controls with healthy skin (n = 7) and normal skin scar (n = 7) both by immunohistochemistry and Western blot analysis. Both immunohistochemistry and Western blot analysis revealed a decrease in the ratio of collagen I/III due to a concomitant increase in collagen III. The patients with incisional hernias and with recurrent incisional hernias showed a ratio of 1.0 +/- 0.1 and 0.8 +/- 0.1, respectively, whereas the controls exhibit a ratio of 2.1 +/- 0.2 in healthy skin and of 1.2 +/- 0.2 in normal skin scar, respectively. The decrease was highly significant (p < 0.01) between the patients with either primary or recurrent hernia and the controls or the normal scar, as well as between controls and normal scar, whereas there was not any significant difference between primary and recurrent hernia (p > 0.05). Our data for the first time confirmed that the presence of incisional hernia is accompanied by impaired collagen synthesis in the skin. The decreased tensile strength of collagen type III may play a key role in the development of incisional hernias. Furthermore, it might explain the high recurrence rates of hernia repair by simple closure, as a repetition of the primarily failing technique, and the improvement by the additional use of alloplastic material.

Expression of heat shock protein 70 (HSP70) at the interface of polymer-implants in vivo

Synthetic polymer meshes are widely applied in the modern surgical approach for repairing abdominal wall defects. The implanted material is often observed leading to post-operative complications such as deficient abdominal wall mobility and adhesion formation with the abdominal cavity and/or abdominal organs. However, the functioning of the implant is primarily affected by the wound healing process guided by inflammatory events occurring at the tissue-material interface. This could presumably be influenced by the physicochemical properties of the polymer. With regard to it, the cellular and molecular processes involved in the successful restoration of the abdominal wall function are poorly understood. The present in vivo study, therefore, exemplary investigated in a rat model, the commercially available polymer-meshes Prolene (polypropylene, PP), Mersilene (polyester, PE) and Vicryl (polyglactin 910), as well as new mesh variants consisting either of PP (EB) or a combination of PP and polyglactin 910 (A plus or Vypro). The implanted material was evaluated by light and electron microscopy, immunohistochemistry as well as morphometry over an implantation period of 90 days. The data show that polymers induce heat shock protein (HSP)70, and its expression at the interface correlates inversely with the activity of the inflammatory reaction in vivo. Further, an ascent in HSP70 expression parallels the increasing implantation period and evolving foreign-body granulomas. Accordingly, a major role for HSP70 in modulating the local acceptance of polymers and as an additional marker for in vivo testing of polymers is suggestive.

Diagnostic relevance of chromosomal in-situ hybridization in Merkel cell carcinoma: targeted interphase cytogenetic tumour analyses

AIMS

To resolve the conflicting diagnoses of five pathologists (which included well-differentiated neuroendocrine carcinoma, malignant carcinoid, undifferentiated small-cell carcinoma, primitive neuroectodermal tumour, metastases of small-cell lung carcinoma (SCLC) and Merkel cell carcinoma (MCC)), and tumour-free lungs after necropsy, we investigated an alarmingly metastasizing MCC in a 32-year-old Caucasian man using chromosomal in-situ hybridization (CISH). Differences in incidence and course in males and females also prompted targeted analyses for chromosomes X and Y. The lesion was also analysed for p53 gene mutations.

METHODS AND RESULTS

Paraffin sections of the thorax, buccal lymph nodes and scalp tumours were stained with haematoxylin and eosin. Immunohistochemistry was performed with antibodies against pancytokeratin, keratin 20, neuron-specific enolase (NSE), chromogranin, neurofilaments and vimentin, among others. Sections (5-6 microm) of the tumours were analysed with alpha-satellite probes for chromosomes 1, 6, 7, 11, 12, 17, 18, X and Y using CrSH; and exons 5-9 of the p53 gene were examined by polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) methods. Although positive for pancytokeratin, keratin 20, chromogranin, NSE, synaptophysin and vimentin, the similarity in antigen profiles expressed by SCLC and MCC prevented a definitive tumour diagnosis. Chromosomal in-situ hybridization, however, revealed trisomies 1 and 11, two frequent aberrations in MCC, and trisomy 18. Moreover, 71% of the tumour cells had two to three copies of X, whereas 98% of the cell nuclei in the hair follicles and normal epidermis (purported Merkel cell origins) displayed one X chromosome. No mutations were detected in the five exons of the p53 gene examined.

CONCLUSIONS

Had CISH been performed earlier, treatment may have been tailored specifically to suit MCC, since MCC and SCLC have different therapeutic strategies. Finally, chromosome X may be of prognostic relevance in MCC, which apparently predominates in females and yet shows poorer prognosis in males, and hence be worthy of further investigation.

Septic shock

1. Septic shock is still a major complication of patients in intensive care units (ICUs) and, therefore, a main goal of ICU-related research. 2. After the unsatisfying results of multicenter clinical trials in blocking proinflammatory mediators such as tumor necrosis factor and interleukin-1 or endotoxin itself, research has focused on other important members of the cytokine pathways--in particular, anti-inflammatory cytokines such as interleukin 10. Moreover, there is an increasing knowledge of intracellular activation and deactivation pathways, inaugurating the theoretical advantage to block, attenuate or manipulate the inflammatory response at an early stage of disease or in a more specific fashion. 3. This review points out new developments in our understanding of the pathophysiology of septic shock and gives an example of a more recent approach in septic shock research--the heat shock response.

Monocyte-biomaterial interaction inducing phenotypic dynamics of monocytes: a possible role of monocyte subsets in biocompatibility

For the in vitro study of cell-biomaterial surface interactions, the choice of cell type is crucial. In vivo data indicate that during the healing of the implant in the tissues, the pivotal cell types are the macrophages. These cells, upon interaction with any foreign material, might initiate a spectrum of responses, which could lead to acute and chronic inflammatory changes affecting the biocompatibility of the implant. Whether the mechanisms governing the type of evolving inflammatory reaction could be attributed to the macrophages functional differentiation mirrored by monocyte subsets during the polymer interaction, is poorly described. This in vitro study, therefore, attempted to investigate whether different biomaterials influence monocyte cellular activity, determined by the myeloperoxidase level and mitochondrial XTT cleavage, and phenotype dynamics characterized by the presence of CD14, RM 3/1 and 27E10 antigens. It is shown that different polymers exert differential potential to influence monocytes, both in their cellular activity and their phenotypic pattern. Thus, these findings demonstrating material-induced monocyte activation and monocyte phenotype modulation, are suggestive of the monocyte role as reporter cells in evaluating the biocompatibility of a synthetic medical device.

Human dermal microvascular endothelial cells express the melanocortin receptor type 1 and produce increased levels of IL-8 upon stimulation with alpha-melanocyte-stimulating hormone

Pro-opiomelanocortin (POMC)-derived peptides such as alpha-melanocyte-stimulating hormone (alpha-MSH) recently have been recognized as mediators with potent immunomodulating and anti-inflammatory properties. Their effects are mediated via different protein G-coupled melanocortin (MC) receptors that are capable to bind one or more POMC-derived peptides. Among these receptors, MC-1 is specific for alpha-MSH and adrenocorticotropin. The purpose of the present study was to investigate whether MC receptors are expressed on normal human dermal microvascular endothelial cells (HDMEC) as well as transformed human dermal microvascular endothelial cells (HMEC-1). Using semiquantitative reverse transcriptase-PCR and MC receptor-specific primers, both HDMEC and HMEC-1 were found to express MC-1 constitutively. In addition, MC-1 expression was increased upon stimulation with IL-1beta or alpha-MSH itself. Other known MC receptors were neither detectable in unstimulated nor in IL-1beta- or alpha-MSH-stimulated cells. The binding of alpha-MSH by HMEC-1 was specific and saturable as demonstrated by competitive and saturation-binding studies with 125I-labeled alpha-MSH (Kd: 1.1 nM). To evaluate the physiologic relevance of MC-1 expression, HMEC-1 were treated with various concentrations of alpha-MSH (10(-15)-10(-6) M) and were investigated for their cytokine-producing capacity. Alpha-MSH (10(-10)-10(-8) M) significantly up-regulated IL-8 release and mRNA expression by HMEC-1. In contrast, the production of IL-1 or IL-6 by HMEC-1 was not affected upon treatment with alpha-MSH. These data provide first evidence that HDMEC express functional MC receptors. Therefore, alpha-MSH, which is released in the skin during cutaneous inflammation via inducing chemokines may represent an important signal required for leukocyte-endothelial cell interaction.

Human dermal microvascular endothelial cells express the melanocortin receptor type 1 and produce increased levels of IL-8 upon stimulation with alpha-melanocyte-stimulating hormone

Pro-opiomelanocortin (POMC)-derived peptides such as alpha-melanocyte-stimulating hormone (alpha-MSH) recently have been recognized as mediators with potent immunomodulating and anti-inflammatory properties. Their effects are mediated via different protein G-coupled melanocortin (MC) receptors that are capable to bind one or more POMC-derived peptides. Among these receptors, MC-1 is specific for alpha-MSH and adrenocorticotropin. The purpose of the present study was to investigate whether MC receptors are expressed on normal human dermal microvascular endothelial cells (HDMEC) as well as transformed human dermal microvascular endothelial cells (HMEC-1). Using semiquantitative reverse transcriptase-PCR and MC receptor-specific primers, both HDMEC and HMEC-1 were found to express MC-1 constitutively. In addition, MC-1 expression was increased upon stimulation with IL-1beta or alpha-MSH itself. Other known MC receptors were neither detectable in unstimulated nor in IL-1beta- or alpha-MSH-stimulated cells. The binding of alpha-MSH by HMEC-1 was specific and saturable as demonstrated by competitive and saturation-binding studies with 125I-labeled alpha-MSH (Kd: 1.1 nM). To evaluate the physiologic relevance of MC-1 expression, HMEC-1 were treated with various concentrations of alpha-MSH (10(-15)-10(-6) M) and were investigated for their cytokine-producing capacity. Alpha-MSH (10(-10)-10(-8) M) significantly up-regulated IL-8 release and mRNA expression by HMEC-1. In contrast, the production of IL-1 or IL-6 by HMEC-1 was not affected upon treatment with alpha-MSH. These data provide first evidence that HDMEC express functional MC receptors. Therefore, alpha-MSH, which is released in the skin during cutaneous inflammation via inducing chemokines may represent an important signal required for leukocyte-endothelial cell interaction.

Interaction of murine dendritic cells with collagen up-regulates allostimulatory capacity, surface expression of heat stable antigen, and release of cytokines

In vivo, dendritic cells (DC) reside in direct proximity to extracellular matrix (ECM) proteins. Because ECM proteins affect morphology and function of a number of cell types, this study investigated potential effects of ECM proteins on functional properties of DC. DC were generated from murine bone marrow cultures, supplemented with granulocyte-macrophage colony-stimulating factor, and subsequently cultured on tissue culture plates coated with various ECM proteins. Among the ECM proteins tested, collagen (COL) up-regulated the T cell stimulatory capacity of DC. This effect was accompanied by sustained surface expression of the co-stimulatory molecule heat stable antigen on DC and by enhanced release of interleukin-1 and interleukin-6, respectively. Because fibronectin or solubilized COL were unable to cause similar changes in DC phenotype or function, we conclude that adherence to COL interferes specifically with DC function. These data suggest that ECM proteins may be involved in regulation of DC phenotype as well as in their functional activation.

Regulation of the immune response by epidermal cytokines and neurohormones

The ability of the cellular components of the skin immune system to mount various types of immune responses is largely dependent upon their ability to release and to respond to different signals provided by immunoregulatory mediators such as cytokines and neuropeptides. In principle, almost every cytokine known so far, including interleukins (IL), interferons (IFN), tumor necrosis factors (TNF), colony stimulating factors (CSF) and several growth factors can be detected in the skin under certain physiological or pathological conditions. There is recent evidence that neuropeptides such as substance P, calcitonin-related gene product (CGRP) a.o. as well as neurohormones such as proopiomelanocortin (POMC), which is the precursor of several peptidehormones including melanocyte stimulating hormones (MSH), are present in epidermal cells, cutaneous tumors and inflammatory cells infiltrating the skin. In addition to their well known functions as neurotransmitters or hormones, these peptides have recently been recognized as potent immunomodulating agents which inhibit the production and activity of immunoregulatory and proinflammatory cytokines (IL-1, IL-2, IFN gamma) but induce the release of factors, e.g., IL-10, which downregulate immune responses. Accordingly, in animals, alpha MSH and CGRP have been shown to inhibit the induction of contact hypersensitivity reactions. Therefore, a complex network of interacting mediators including cytokines and neuropeptides within the cutaneous microenvironment are crucial elements of the induction, elicitation and regulation of cutaneous immune responses.

Pro-opiomelanocortin-derived peptides induce IL-10 production in human monocytes

There is strong evidence for the existence of a neuroimmune axis which is regulated by a network of interacting cytokines and neuropeptides. Accordingly, pro-opiomelanocortin-derived peptide hormones such as melanocyte-stimulating hormones (MSH), adrenocorticotropin, and beta-endorphin not only could be detected in many immunocompetent cells but also turned out to be potent immunomodulating and anti-inflammatory mediators, mainly through regulating cytokine production. Thus, it was investigated whether alpha-MSH, which is known to inhibit immune and inflammatory responses, would influence the production of the cytokine synthesis inhibitor IL-10 by human PBMC. Stimulation of PBMC with alpha-MSH resulted in a significantly enhanced release of, IL-10 protein. These data were confirmed by Northern blot analysis, which demonstrated increased IL-10 mRNA expression induced by alpha-MSH. This effect of alpha-MSH was dose-dependent; maximum IL-10 release and mRNA expression were obtained at a concentration of 10(-13) M. There is also clear evidence that only the C-terminal tripeptide of alpha-MSH was required to enhance IL-10 production. In addition, alpha-MSH and its tripeptide strongly induced IL-10 in purified monocytes. In contrast, neither unstimulated nor activated T lymphocytes produced increased amounts of IL-10 in response to alpha-MSH. These findings indicate that pro-opiomelanocortin peptides such as alpha-MSH are able to up-regulate the production of suppressor factors such as IL-10 in monocytes and thereby may contribute to immunosuppression.

Pro-opiomelanocortin-derived peptides induce IL-10 production in human monocytes

There is strong evidence for the existence of a neuroimmune axis which is regulated by a network of interacting cytokines and neuropeptides. Accordingly, pro-opiomelanocortin-derived peptide hormones such as melanocyte-stimulating hormones (MSH), adrenocorticotropin, and beta-endorphin not only could be detected in many immunocompetent cells but also turned out to be potent immunomodulating and anti-inflammatory mediators, mainly through regulating cytokine production. Thus, it was investigated whether alpha-MSH, which is known to inhibit immune and inflammatory responses, would influence the production of the cytokine synthesis inhibitor IL-10 by human PBMC. Stimulation of PBMC with alpha-MSH resulted in a significantly enhanced release of, IL-10 protein. These data were confirmed by Northern blot analysis, which demonstrated increased IL-10 mRNA expression induced by alpha-MSH. This effect of alpha-MSH was dose-dependent; maximum IL-10 release and mRNA expression were obtained at a concentration of 10(-13) M. There is also clear evidence that only the C-terminal tripeptide of alpha-MSH was required to enhance IL-10 production. In addition, alpha-MSH and its tripeptide strongly induced IL-10 in purified monocytes. In contrast, neither unstimulated nor activated T lymphocytes produced increased amounts of IL-10 in response to alpha-MSH. These findings indicate that pro-opiomelanocortin peptides such as alpha-MSH are able to up-regulate the production of suppressor factors such as IL-10 in monocytes and thereby may contribute to immunosuppression.

alpha-Melanocyte-stimulating hormone induces hapten-specific tolerance in mice

alpha-Melanocyte-stimulating hormone (alpha-MSH) is a proopiomelanocortin-derived peptide with known immunoregulatory effects, acting mainly via modulation of cytokine secretion by lymphocytes and monocytes. When applied epicutaneously, alpha-MSH inhibits both induction as well as elicitation of contact hypersensitivity (CHS) responses in mice. We questioned whether systemically administered alpha-MSH leads to the induction of hapten-specific tolerance. For this purpose, mice were injected i.v. with 75 microgram/kg synthetic bioactive alpha-MSH 2 h before sensitization (day 0) or challenge (day 6) with the hapten, trinitrochlorobenzene (TNCB). Intravenous administration of alpha-MSH 2 h before sensitization or 2 h before challenge resulted in a markedly reduced CHS response. To distinguish between unresponsiveness and tolerance, these mice were sensitized and challenged a second time, but in the absence of alpha-MSH. Mice that had been injected with alpha-MSH before the first sensitization (day 0), but not before challenge (day 6), were also unable to develop a significant CHS response after an additional sensitization and challenge with the same Ag 10 to 14 days later. In contrast, sensitization to the unrelated hapten, dinitrofluorobenzene, was unaffected in these mice, indicating the induction of hapten-specific tolerance by alpha-MSH. Moreover, regional lymph node cells obtained from alpha-MSH-treated mice 5 days after resensitization failed to produce IL-2 in response to trinitrobenzosulfonic acid, the water-soluble analogue of TNCB, whereas lymph node cells from TNCB-sensitized, not alpha-MSH-treated, mice as well as from mice treated with alpha-MSH before challenge readily exhibited trinitrobenzosulfonic acid-specific IL-2 production in this assay. Finally, in vivo tolerance induction by alpha-MSH could be abrogated by the administration of anti-IL-10 Ab at the site of sensitization. These data indicate that alpha-MSH, in addition to its suppressive effect on induction and elicitation of CHS, is able to induce hapten-specific tolerance in mice. Thus, alpha-MSH may be a significant regulatory mediator of cutaneous immune responses in vivo.

alpha-Melanocyte-stimulating hormone induces hapten-specific tolerance in mice

alpha-Melanocyte-stimulating hormone (alpha-MSH) is a proopiomelanocortin-derived peptide with known immunoregulatory effects, acting mainly via modulation of cytokine secretion by lymphocytes and monocytes. When applied epicutaneously, alpha-MSH inhibits both induction as well as elicitation of contact hypersensitivity (CHS) responses in mice. We questioned whether systemically administered alpha-MSH leads to the induction of hapten-specific tolerance. For this purpose, mice were injected i.v. with 75 microgram/kg synthetic bioactive alpha-MSH 2 h before sensitization (day 0) or challenge (day 6) with the hapten, trinitrochlorobenzene (TNCB). Intravenous administration of alpha-MSH 2 h before sensitization or 2 h before challenge resulted in a markedly reduced CHS response. To distinguish between unresponsiveness and tolerance, these mice were sensitized and challenged a second time, but in the absence of alpha-MSH. Mice that had been injected with alpha-MSH before the first sensitization (day 0), but not before challenge (day 6), were also unable to develop a significant CHS response after an additional sensitization and challenge with the same Ag 10 to 14 days later. In contrast, sensitization to the unrelated hapten, dinitrofluorobenzene, was unaffected in these mice, indicating the induction of hapten-specific tolerance by alpha-MSH. Moreover, regional lymph node cells obtained from alpha-MSH-treated mice 5 days after resensitization failed to produce IL-2 in response to trinitrobenzosulfonic acid, the water-soluble analogue of TNCB, whereas lymph node cells from TNCB-sensitized, not alpha-MSH-treated, mice as well as from mice treated with alpha-MSH before challenge readily exhibited trinitrobenzosulfonic acid-specific IL-2 production in this assay. Finally, in vivo tolerance induction by alpha-MSH could be abrogated by the administration of anti-IL-10 Ab at the site of sensitization. These data indicate that alpha-MSH, in addition to its suppressive effect on induction and elicitation of CHS, is able to induce hapten-specific tolerance in mice. Thus, alpha-MSH may be a significant regulatory mediator of cutaneous immune responses in vivo.

IL-12 is expressed and released by human keratinocytes and epidermoid carcinoma cell lines

IL-12 is a 70-kDa heterodimeric cytokine composed of two covalently linked chains, p40 and p35. IL-12 has multiple effects on T and NK cells and recently was found to be required for optimal Th1 cell development. In a variety of inflammatory skin disorders including delayed type hypersensitivity and contact hypersensitivity, Th1 cells appear to be critically involved. Because keratinocytes are well known to exhibit the capacity to release a variety of proinflammatory and immunologic cytokines, and thereby to be able to modulate inflammatory and immune reactions within the skin, it was investigated whether human keratinocytes and keratinocyte cell lines can release IL-12. Supernatants of phorbol-12,13-dibutyrate (PDBu) stimulated human epidermoid carcinoma cell lines (KB, A431) induced IFN-gamma production by PBL. This activity could be completely blocked by the addition of an anti-IL-12 Ab directed against the p40 subunit of IL-12 (C8.6). Release of IL-12 by keratinocyte cell lines was further confirmed by an RIA specific for p40. Immunoprecipitation under reducing conditions using the C8.6 Ab yielded specific bands at 40 kDa in supernatants of both KB cells and normal human keratinocytes. Northern blot analysis revealed IL-12-specific mRNA transcripts in PDBu-treated KB cells using cDNA probes encoding for p35 and p40. Moreover, by reverse transcription PCR specific transcripts for p35 and p40 were found in keratinocytes. These data indicate that keratinocyte cell lines and, although to a much lesser degree, normal human keratinocytes, exhibit the capacity to make IL-12; thus demonstrating for the first time IL-12 production by nonhemopoietic cells. Thus, one may speculate that keratinocytes via this capacity may influence the fate of Th-mediated immune responses, favoring Th1 responses by enhanced production of IL-12 or Th2 responses by reduced IL-12 release.

IL-12 is expressed and released by human keratinocytes and epidermoid carcinoma cell lines

IL-12 is a 70-kDa heterodimeric cytokine composed of two covalently linked chains, p40 and p35. IL-12 has multiple effects on T and NK cells and recently was found to be required for optimal Th1 cell development. In a variety of inflammatory skin disorders including delayed type hypersensitivity and contact hypersensitivity, Th1 cells appear to be critically involved. Because keratinocytes are well known to exhibit the capacity to release a variety of proinflammatory and immunologic cytokines, and thereby to be able to modulate inflammatory and immune reactions within the skin, it was investigated whether human keratinocytes and keratinocyte cell lines can release IL-12. Supernatants of phorbol-12,13-dibutyrate (PDBu) stimulated human epidermoid carcinoma cell lines (KB, A431) induced IFN-gamma production by PBL. This activity could be completely blocked by the addition of an anti-IL-12 Ab directed against the p40 subunit of IL-12 (C8.6). Release of IL-12 by keratinocyte cell lines was further confirmed by an RIA specific for p40. Immunoprecipitation under reducing conditions using the C8.6 Ab yielded specific bands at 40 kDa in supernatants of both KB cells and normal human keratinocytes. Northern blot analysis revealed IL-12-specific mRNA transcripts in PDBu-treated KB cells using cDNA probes encoding for p35 and p40. Moreover, by reverse transcription PCR specific transcripts for p35 and p40 were found in keratinocytes. These data indicate that keratinocyte cell lines and, although to a much lesser degree, normal human keratinocytes, exhibit the capacity to make IL-12; thus demonstrating for the first time IL-12 production by nonhemopoietic cells. Thus, one may speculate that keratinocytes via this capacity may influence the fate of Th-mediated immune responses, favoring Th1 responses by enhanced production of IL-12 or Th2 responses by reduced IL-12 release.

Proopiomelanocortin production by epidermal cells: evidence for an immune neuroendocrine network in the epidermis

Proopiomelanocortin (POMC) is known to be synthesized in the pituitary gland and is subsequently cleaved by specific prohormone convertases into biologically active peptide hormones such as melanocyte stimulating hormones (MSH), adrenocorticotropin (ACTH) and endorphins (EP). Guanine nucleotide-binding protein (G-protein)-coupled receptors, which have only recently been discovered, are involved in the transmission of their message. There is also evidence indicating that POMC is not only produced by pituitary cells but is an ubiquitous molecule, that is cleaved cell- and tissue-specific. It has also been shown that the epidermis keratinocytes as well as melanocytes express POMC upon stimulation and release alpha MSH and ACTH. In addition to their function as hormones, POMC peptides have been shown to exert a variety of immunoregulatory effects by modulating the function of immunocompetent cells as well as cytokines. These findings provide further evidence for the immunoneuroendocrine network playing a crucial role during the pathogenesis of immune and inflammatory skin disease.

The calcium-binding proteins MRP8 and MRP14 form a membrane-associated heterodimer in a subset of monocytes/macrophages present in acute but absent in chronic inflammatory lesions

Monocytes/macrophages expressing an epitope recognized by a monoclonal antibody 27E10 are present in acute but are absent in chronic inflammatory disorders. This report shows that the 27E10 antigen is formed by noncovalent association of the two Ca(2+)-binding proteins MRP8 and MRP14 which belong to the S100 protein family. Identification has been confirmed immunochemically, by matrix-assisted UV-laser desorption/ionization spectrometry and by partial amino acid sequencing. Surface expression of the MRP8/MRP14 complex on a subset of monocytes is reported for the first time and shown to be up-regulated in a Ca(2+)-dependent manner. The 27E10 surface-positive monocytes isolated by cell separation techniques release high amounts of tumor necrosis factor-alpha and interleukin-1 beta in contrast to their 27E10 surface-negative counterparts thus emphasizing their role in inflammation.

Differential identification of Mycobacterium tuberculosis from various clinical specimens from Sassoon General Hospital, Pune

A total of 619 clinical specimens from cases of pulmonary and extrapulmonary tuberculosis were processed by smear, culture and biochemical tests. Acid fast bacilli could be demonstrated in 93 samples (15.02%) by Z.N. staining method. Culture yielded positive growth in 95 samples (15.35%) M. tuberculosis human type was the most predominient pathogen obtained from 82 cultures (13.40%) M tuberculosis bovine type was isolated from 2 cases of ascitic fluids (0.32%). Atypical Mycobacteria were isolated from 11 samples (1.73%). 5 turned out to be M. scrofulacium, 4 were M. Kansasii, 1 was M. phlei and 1 was M. smegmatis.

Calcium-dependent complex assembly of the myeloic differentiation proteins MRP-8 and MRP-14

MRP-8 and MRP-14 are calcium-binding proteins belonging to the S-100 protein family which have been shown to be associated with specific stages of myeloic/monocytic cell differentiation. Members of this protein family are shown to form homo- and heterodimers. Complex formation has also been observed in preliminary experiments for MRP-8 and MRP-14. To evaluate the in vivo relevance of the MRP complex formation and the stoichiometric ratio of individual components complexes were isolated from granulocytes and monocytes by immunoaffinity chromatography using monospecific antibodies. The purified fraction of the MRPs was found to contain monomers and dimers as shown on sodium dodecyl sulfate-polyacrylamide gel electrophoresis by silver staining and immunoblotting. Similar results were obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of crude cell extracts. The existence of the MRP complexes in vivo was demonstrated by chemical cross-linking and subsequent isolation of complexes by immunoaffinity chromatography. Two new, highly abundant complexes were found in addition to the heterodimer, but neither monomers nor homodimers were detected. The two larger protein complexes (35.0 and 48.5 kDa) were identified as [MRP-8)2.(MRP-14] trimer and [MRP-8)2.(MRP-14)2) tetramer, respectively. All complexes could be shown to be noncovalently associated in vivo. Furthermore, the association of MRPs was shown to be Ca2+ dependent.