Biomedical subjects

K Herrmann

Publications and source records attributed to K Herrmann.

At least 19 recordsLinked to original sources

PubMed2007

[18F-FDG-PET in therapy response of esophageal cancer].

PET imaging with the glucose analog fluorodeoxyglucose (FDG-PET) has been evaluated in several studies to monitor tumor response in patients undergoing chemo- and radiotherapy. The clinical value of FDG-PET for differentiation of residual tumor and therapy induced fibrosis has been documented for esophageal cancer. Furthermore, there are now several reports suggesting that quantitative assessment of therapy induced changes in tumor FDG-uptake may allow prediction of tumor response and patient outcome very early in the course of therapy. This suggests that FDG-PET may be used to identify non-responders early during neoadjuvant chemoradiotherapy allowing for early modifications of the treatment protocol.

Esophageal Neoplasms↗

PubMed2006

After shrinkage apoptotic cells expose internal membrane-derived epitopes on their plasma membranes.

Apoptosis and phagocytosis of apoptotic cells are crucial processes. At best the phagocytic machinery detects and swallows all apoptotic cells in a way that progression to secondary necrosis is avoided. Otherwise, inflammation and autoimmune diseases may occur. Most apoptotic cells are phagocytosed instantaneously in a silent fashion; however, some dying cells escape their clearance. If the cells are not cleared early, they lose membranes due to extensive shedding of membrane surrounded vesicles (blebbing) and shrink. It is unclear how apoptotic cells compensate their massive loss of plasma membrane. Here, we demonstrate that endoplasmic reticulum- (ER) resident proteins (calnexin, the KDEL receptor and a dysfunctional immunoglobulin heavy chain) were exposed at the surfaces of shrunken late apoptotic cells. Additionally, these cells showed an increased binding of lectins, which recognize sugar structures predominantly found as moieties of incompletely processed proteins in ER and Golgi. In addition the ER resident lipophilic ER-Tracker Blue-White DPX, and internal GM1 were observed to translocate to the cell surfaces during late apoptosis. We conclude that during blebbing of apoptotic cells the surface membrane loss is substituted by immature membranes from internal stores. This mechanism explains the simultaneous appearance of preformed recognition structures for several adaptor proteins known to be involved in clearance of dead cells.

Animals↗

PubMed2004

Crohn disease of the small bowel proximal to the terminal ileum: detection by MR-enteroclysis.

BACKGROUND: Although Crohn disease (CD) can affect the entire alimentary tract, the proportion of patients with small-bowel inflammation proximal to the terminal ileum is still unclear. Magnetic resonance imaging (MRI) combined with small-bowel enteroclysis can detect inflammatory lesions of the small bowel. Hence, we applied MR-enteroclysis to assess the percentage of patients with small-bowel inflammation proximal to the terminal ileum among patients with CD and abdominal pain. METHODS: Twenty-five consecutive patients with low, active CD of the colon and/or terminal ileum and episodes of abdominal pain were examined by both MR-enteroclysis and conventional enteroclysis. The findings of MR-enteroclysis were compared with endoscopic and histological results in the terminal ileum and conventional enteroclysis in the small bowel proximal to the terminal ileum. RESULTS: In 13 of the 25 patients, inflammation of the small bowel proximal to the terminal ileum was shown by MR-enteroclysis, whereas in only 4 of the 25 patients, signs of inflammation of the small bowel proximal to the terminal ileum were shown by conventional enteroclysis, all of which were demonstrated by MR-enteroclysis. MR-enteroclysis confirmed the findings in 22 of 25 patients in whom endoscopy and histology had shown inflammation (16 of 18) or no inflammation (6 of 7) of the terminal ileum. CONCLUSION: In symptomatic patients with CD even of low activity, inflammation of the small bowel proximal to the terminal ileum is frequent.

Adult↗

PubMed2003

Epstein-Barr virus infection in colorectal neoplasms associated with inflammatory bowel disease: detection of the virus in lymphomas but not in adenocarcinomas.

Epstein-Barr virus (EBV) is associated with several lymphoid and epithelial human malignancies. The latter include gastric adenocarcinomas, while sporadic colorectal adenocarcinomas (CRCs) have been reported to be EBV-negative. Recently, increased numbers of EBV-infected B lymphocytes have been detected in intestinal mucosal samples affected by ulcerative colitis (UC) and, to a lesser extent, Crohn's disease (CD). Both CRC and colorectal non-Hodgkin's lymphoma (NHL) are recognized complications of inflammatory bowel disease (IBD), but it is unclear to what extent EBV contributes to the development of these neoplasms. Seventeen cases of IBD-associated CRC and nine cases of IBD-associated colorectal NHL were therefore studied for the presence of EBV by in situ hybridization. EBV-positive cases were further studied for the expression of the EBV-encoded nuclear antigen (EBNA) 2 and the latent membrane protein (LMP) 1 of EBV by immunohistochemistry. Four out of seven cases of colorectal NHL associated with UC were shown to be EBV-positive. In addition, two of two colorectal NHLs developing in patients with CD were EBV-positive. Of the EBV-positive lymphomas, three displayed a pattern of EBV latent gene expression consistent with type I latency (EBNA2(-)/LMP1(-)), two a type II pattern (EBNA2(-)/LMP1(+)), and one a type III pattern (EBNA2(+)/LMP1(+)). These findings suggest that EBV infection is involved in the pathogenesis of a proportion of colorectal NHLs developing in IBD. Iatrogenic immunosuppression may contribute to the development of these lymphomas. By contrast, all 17 IBD-associated CRCs were EBV-negative, including a case of CRC occurring synchronously with an EBV-positive NHL. In conjunction with previous reports on sporadic CRCs, this suggests that EBV is not involved in the pathogenesis of CRC.

Adenocarcinoma↗

PubMed2003

[MRI in Crohn's disease after transduodenal contrast administration using negative oral MRI contrast media].

PURPOSE: To compare the efficacy and quality of conventional and MR enteroclysis with different filling methods regarding the assessment of extension and extraluminal manifestations in Crohn's disease. MATERIAL AND METHODS: 190 patients with known Crohn's disease were studied following small bowel enteroclysis, after oral administration or direct transduodenal filling in the MRI-department.T1- and T2-weighted breathhold MRI-scans w/o spectral fat suppression w/o i.v. Gd-DTPA were applied using negative oral superparamagnetic contrast media. RESULTS: Typical findings were marked bowel wall thickening with laminated wall contrast enhancement. In 135 patients 98,2% of affected bowel segments, 97,5% of stenoses and all 16 fistulas were detected, when conventional enteroclysis was employed as standard of reference. Additional important extraluminal findings such as ileoileal (n = 18), ileosigmoidal adhesions (n = 12), extraluminal abscesses (n = 35) and pseudotumors (n = 8) were visualized in 73/135 patients. Concerning the distension of jejunum and ileum, oral filling was rated significantly inferior to transduodenal filling in all small bowel segments,whereas filling in the MRI-unit was rated superior to fluoroscopic, mostly due to a mean transport time of 20 min to the MRI-unit. CONCLUSION: No clinically important findings of enteroclysis were missed when using MRI. Therefore, in patients with Crohn's disease, conventional enteroclysis can be replaced by MRI. For optimal bowel distension oral contrast administration is inferior to transduodenal filling, if a larger time delay between filling and the MRI-scan can be avoided.

Administration, Oral↗

PubMed2001

[Diagnostic value of different rectal contrast media in the detection of colorectal diseases by multi-slice CT].

PURPOSE: Assessment of 3 different rectal contrast agents (water, methylcellulose, ultrasound gel) for their suitability for colorectal imaging in multislice CT (MS-CT). METHODS: 115 patients with colorectal diseases underwent MS-CT with varying, rectal contrast agents in a prospective study. Images were assessed by 2 independent CT-experienced radiologists. 6 criterias were evaluated, using a 5-point scale. RESULTS: Methylcellulose (MC) proved to be significantly superior to ultrasound gel (US). Especially, differentiation of healthy and diseased bowel and bowel wall and lumen were aided, which was proven by quantitative analysis of attenuation values. Rectal distension is greater using MC or US than for water. More proximal parts of the colon could be better distended with water. The interobserver correlation was good (kappa 0.76). CONCLUSIONS: Rectal filling with MC significantly improves diagnostic confidence in colorectal examinations. Ease of administration and lack of problems suggest its use as a clinical routine tool.

Adult↗

PubMed2001

[Multidetector-row CT of the lungs: Multiplanar reconstructions and maximum intensity projections for the detection of pulmonary nodules].

PURPOSE: The present study was performed to evaluate the utility of axial, coronal and sagittal multiplanar reformations (MPR) and maximum intensity projections (MIP) in the detection of pulmonary nodules as compared to axial standard reconstructions (SR). MATERIALS AND METHODS: 103 patients with suspicion or evidence of pulmonary nodules underwent multidetector-row computed tomography (MDCT; Somatom plus 4 Volume Zoom, Siemens, Germany) of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 1 mm and a pitch of 6 and underwent reconstruction with 0.6 mm increment. MPR and MIP in three planes [5 mm slice thickness (SL), 4 mm increment] were calculated from the raw data and compared to axial SR (5 mm SL). Three blinded observers evaluated the number, size and the quality of depiction of pulmonary nodules according to a 3-point confidence scale (1 = certain, 2 = probable, 3 = uncertain). Four patient groups were formed using the axial SR. Group 1 presenting no nodules, group 2 presenting probable nodules and group 3 presenting definitively lung nodules. Patients with more than 7 pulmonary nodules (group 4) were not included in the study. The 1 mm slice was used as the gold standard. RESULTS: Inter-observer correlation was good at r = 0.77. MIP were superior in the depiction of pulmonary nodules at a statistically significant level of p < 0.05 (mean values in group 3 = 2.58 to 1.97 and group 2 = 0.99 to 0.79 with MIP and SR, respectively). In four patients 6 additional lesions were identified with MIP that were missed with axial SR. Overall, with SR 72 nodules, with MPRs 78, and with MIPs 99 nodules were delineated. Pulmonary nodules larger than 5 mm in size were equally well depicted with both modalities, whereas lesions smaller than 5 mm in size were significantly better depicted with MIP (p < 0.05). Diagnostic confidence for all lesions was highest with MIP and least with SR. CONCLUSION: MIP reformations on the basis of MDCT data sets are superior in the depiction and diagnosis of pulmonary nodules as compared to axial standard reconstructions and MPR.

Adolescent↗

PubMed2001

Shaping of colony elements in Laomedea flexuosa Hinks (Hydrozoa, Thecaphora) includes a temporal and spatial control of skeleton hardening.

The colonies of thecate hydroids are covered with a chitinous tubelike outer skeleton, the perisarc. The perisarc shows a species-specific pattern of annuli, curvatures, and smooth parts. This pattern is exclusively formed at the growing tips at which the soft perisarc material is expelled by the underlying epithelium. Just behind the apex of the tip, this material hardens. We treated growing cultures of Laomedea flexuosa with substances we suspected would interfere with the hardening of the perisarc (L-cysteine, phenylthiourea) and those we expected would stimulate it (dopamine, N-acetyldopamine). We found that the former caused a widening of and the latter a reduction in the diameter of the perisarc tube. At the same time, the length of the structure elements changed so that the volume remained almost constant. We propose that normal development involves a spatial and temporal regulation of the hardening process. When the hardening occurs close to the apex, the diameter of the tube decreases. When it takes place farther from the apex, the innate tendency of the tip tissue to expand causes a widening of the skeleton tube. An oscillation of the position at which hardening takes place causes the formation of annuli.

Animals↗

PubMed2000

[Reconstructive endovascular treatment procedures in the area of the a. subclavia and its branches].

PURPOSE: Principles, methods and results of percutaneous therapy in acute and chronic vascular alterations of the subclavian artery and its branches. MATERIAL AND METHODS: 17 arteries in 15 patients have been treated. The patients suffered from stenoses (n = 6), occlusions (n = 7), aneurysms, (n = 2) or acute hemorrhage (n = 2). The lesions were located in the subclavian artery (n = 8), the axillary artery (n = 4) or the vertebral artery (n = 5). In all cases the procedures were performed via via a transfemoral approach. Balloon angioplasty was employed in 13 cases, in 6 cases bare stents and in 4 cases grafted stents were implanted. In one case additionally local lysis was performed. RESULTS: Primary technical success was achieved in all cases. No catheter complications did occur. In 13 Patients complete follow-up examinations could be performed. The life-threatening acute hemorrhages were stopped without recurrent bleeding. The aneurysms could be completely excluded without endoleaks. In 4 Patients of the stenosis-group re-stenosis occurred and following stent-implantation one occlusion after 6 months was observed. 8 patients are without clinical symptoms since the intervention. CONCLUSION: Stenotic and occlusive vascular alterations as well as aneurysms and the acute hemorrhage in supraaortic arteries can be effectively and safely treated by endovascular techniques using percutaneous groin access.

Adult↗

PubMed2000

Expression of nuclear beta-catenin and c-myc is correlated with tumor size but not with proliferative activity of colorectal adenomas.

Most colorectal cancers have loss-of-function mutations in the adenomatosis polyposis coli (APC) tumor suppressor gene. This leads to the accumulation of nuclear beta-catenin, which, together with the DNA-binding protein TCF-4, functions as a transcriptional activator. The recently defined target genes c-myc, cyclin D1, and matrilysin are responsible for tumor proliferation or malignant progression and explain the oncogenic potential of nuclear beta-catenin. To investigate its role in early colon carcinogenesis, we analyzed the expression of beta-catenin, its target gene c-myc, and the proliferative activity in 88 colorectal adenomas of varying size and grade of dysplasia. The results revealed i) the most significant correlation of nuclear beta-catenin and c-myc expression was not with the grade of dysplasia but with the size of the colon adenoma; ii) perfect correlation of nuclear beta-catenin and c-myc expression; iii) no significant correlation of adenoma size with the proliferative activity; and iv) no significant correlation of proliferative activity and the nuclear expression of beta-catenin and c-myc. These results imply that APC mutations have additional beta-catenin-independent functions; APC mutations alone are not sufficient for nuclear overexpression of beta-catenin; and nuclear beta-catenin has additional important functions for exceeding a threshold tumor size.

Adenoma↗

PubMed2000

Formaldehyde neurotoxicity in animal experiments.

The aim of this study was to determine whether the inhalation of formaldehyde has a neurotoxicological impact. Forty Wistar rats (Lew.1/K) were trained to find food in a maze within a particular time. When all animals were at an equal level, 13 rats inhaled 2.6 ppm and 13 others inhaled 4.6 ppm formaldehyde 10 min/d, 7 d/week for 90 d. The control group comprised 14 animals inhaling water steam according to the same exposure pattern. During the exposure period and the post-trial observation stage (30 d), the time required to find the food and the number of mistakes made on the way were recorded. Between the animals exposed to formaldehyde and the control group a statistically significant difference for both parameters was observed (p < 0.05). The animals exposed to formaldehyde needed more time and made more mistakes than the animals of the control group while going through the maze. The results underline the necessity for a systematic observance of precautions in case of occupational or dwelling-related formaldehyde exposure, and allow us to classify formaldehyde as "probably neurotoxic". Further investigations are required to assess the neurotoxicologic impact of subchronic formaldehyde exposure.

Administration, Inhalation↗

PubMed2000

Long-term follow-up study on SIV intestinal proviral load in rhesus macaques.

After experimental infection with simian immunodeficiency virus (SIV), intestinal endoscopy proved to be an easily tolerated, minimal invasive procedure to obtain biopsies from the gastrointestinal tract of rhesus macaques during all stages of disease. As the GI tract is affected by many opportunistic infections and immunological impairment after SIV/human immunodeficiency virus (HIV) infection, knowledge on the proviral load is an important parameter for a better understanding of disease pathogenesis. In this paper, we describe the set-up and evaluation of a quantitative competitive polymerase chain reaction (PCR) and the quantification of SIV intestinal proviral load in a long-term follow-up study of eight rhesus monkeys (Macaca mulatta) after two different routes of virus inoculation. A SIV-specific signal could be detected as early as day 3 after infection. Of 143 biopsies from the follow-up study, 85.3% showed a positive PCR. DNA copy numbers ranged from 300 to 15,000 molecules per 100,000 cells. No significant influence of the inoculation route could be shown on either proviral load or survival time, but higher SIV proviral load was associated with a more rapid progression to disease. Therefore, the amount of proviral load in intestinal biopsies may be an important prognostic value for the further course of the disease.

Animals↗

PubMed2000

Lack of association of nonautoimmune hyperfunctioning thyroid disorders and a germline polymorphism of codon 727 of the human thyrotropin receptor in a European Caucasian population.

Constitutively activating mutations of the human TSH receptor (hTSHR) gene have been implicated as a major cause of hyperfunctioning nonautoimmune thyroid disease. However, significant geographic differences in the prevalence of these mutations have been observed. Recently, a high frequency of a germline polymorphism at codon 727 of the cytoplasmic tail of the hTSHR has been demonstrated in patients with toxic multinodular goiter. In the present study we assessed whether the codon 727 polymorphism is associated with hyperfunctioning thyroid adenomas. PCR followed by restriction enzyme digestion were used to genotype a total of 128 European Caucasian patients with toxic nonautoimmune thyroid disease (83 with toxic adenoma, 31 with toxic multinodular goiter, and 14 with disseminated autonomy) and to compare their codon 727 polymorphism frequencies with those of 99 healthy controls and 108 patients with Graves' disease. All individuals were drawn from an identical ethnic background. Sequencing of PCR products was used to confirm the mutation analysis. We found no significant differences in codon 727 polymorphism frequencies between patients with autonomously functioning thyroid disorders (13.3%) and the healthy control group (16.2%; P = 0.57). Moreover, the subtypes of toxic nonautoimmune thyroid disease (toxic adenoma, 13.2%; multinodular goiter, 9.6%; disseminated autonomy, 21.4%) were not related to significant differences in codon 727 polymorphism frequencies compared with the healthy control group (P = 0.67, P = 0.40, and P = 0.70, respectively). Additionally, there were no significant differences between patients with Graves' disease (21.3%) and healthy controls (P = 0.38). In conclusion, our data do not support an association between the codon 727 polymorphism of the hTSHR and toxic thyroid adenomas or toxic multinodular goiter in our study population. Thus, the codon 727 polymorphism of the hTSHR does not appear to be involved in the evolution of autoimmune or nonautoimmune hyperthyroidism in the European Caucasian population.

Adenoma↗

PubMed1999

The small proteoglycan fibromodulin is expressed in mitotic, but not in postmitotic fibroblasts.

The small proteoglycan fibromodulin is involved in a variety of adhesion processes of connective tissue, binds to collagen and seems to influence fibrillogenesis by regulating collagen fibril spacing and thickness. Using subtractive hybridisation and Northern blotting, we found expression of the fibromodulin gene only in mitotic but not in mitomycinC-induced postmitotic fibroblasts. Furthermore, we could show that in skin only fibroblasts but not endothelial cells and keratinocytes express fibromodulin. With age the thickness of collagen fibrils increases as well as the occurrence of postmitotic fibroblasts. We could show with different chemotaxis and similar collagen gel contraction experiments further physiological differences between mitotic and postmitotic fibroblasts. This is the first report showing the switch of mitotic to postmitotic fibroblasts at the molecular level. Therefore, fibromodulin provides a specific marker for mitotic versus postmitotic fibroblasts and could indicate cell ageing. Mitomycin C is therapeutically used in bladder carcinoma and could thus induce premature ageing of fibroblasts.

Base Sequence↗

PubMed1999

[Percutaneous implantation of port-catheter systems for intraarterial chemotherapy of the liver].

PURPOSE: The objective of this study was to determine the usefulness, safety and acceptance of a new technique of percutaneous implantation of port-catheter-systems (PIPS) for locoregional intraarterial chemotherapy of the liver. MATERIAL AND METHODS: In 50 patients with malignant hepatic disease, 52 percutaneously implantable port-catheter systems were implanted for intraarterial chemotherapy of the liver as an interventional radiological technique. A commercially available angiographic catheter was placed in the hepatic artery under fluoroscopic control via a transfemoral approach and connected to a Port-A-Cath situated in the groin. This procedure was done on an outpatient basis; no medical treatment was administered. RESULTS: Percutaneous placement of the port-catheter system was successful in all cases, also in those with a hepatomesenteric trunk. No peri- and post-interventional complications occurred. The median patency was 312 days (13-547 days). The catheter-related complication rate was 12%. The function could be restored by replacement or an interventional procedure in all but one case (2%). Infection and leakage did not occur. The system had been withdrawn without complications in 7/52 cases for a variety of reasons (e.g. hemihepatectomy, desire of the patient or clinician, dissection after intervention, replacement). CONCLUSION: Percutaneous placement of a port-catheter system is a safe and easy alternative to the surgical placement of port systems for hepatic intraarterial chemotherapy. Long-term complication rates are comparable. The option of easy withdrawal and interventional correction of dysfunction as well as lower costs are additional advantages.

Adult↗

PubMed1999

TRFK-5 reverses established airway eosinophilia but not established hyperresponsiveness in a murine model of chronic asthma.

We studied the effects of an anti-interleukin (IL)-5 monoclonal antibody (TRFK-5) or dexamethasone (DEX) to reverse already established airway hyperresponsiveness (AHR) and tissue eosinophilia in a Schistosoma mansoni antigen-sensitized and airway-challenged mouse model of chronic asthma. In this model at 4 d after antigen challenge there is dramatic bronchoalveolar lavage fluid (BAL) eosinophilia, AHR to intravenous methacholine (MCh), and histologic evidence of peribronchial eosinophilic infiltration and mucoid cell hyperplasia. These changes persist for up to 2 wk after antigen challenge. Treatment with DEX from Days 4 through 10 significantly reduced established airway eosinophilia compared with animals sham-treated with saline from Days 4 -10 (120 +/- 29 eosinophils/microl BAL for DEX-treated mice versus 382 +/- 60 eosinophils/microl BAL for sham-treated animals, p < 0.01). DEX-treated mice also had dramatically reduced mucoid cell hyperplasia, and airway responsiveness returned to normal. In contrast, TRFK-5 given during the same time period reduced airway eosinophilia (86 +/- 32 eosinophils/microl BAL versus 382 +/- 60 eosinophils/microl BAL, p < 0.01) but did not reduce goblet cell hyperplasia or reverse already established AHR. Treatment with DEX but not TRFK-5 also inhibited interferon gamma (IFN-gamma) content of BAL fluid (0.49 +/- 0.09 ng/ml BAL fluid for DEX versus 1.50 +/- 0.24 ng/ml BAL fluid and 1.36 +/- 0.13 ng/ml BAL fluid for TRFK-5 and sham-treated mice, respectively, both p < 0.001 versus DEX). Thus, treatment with DEX reduces established eosinophilic airway inflammation and AHR in S. mansoni-sensitized and airway-challenged mice but treatment with TRFK-5 reversed established eosinophilia without ameliorating established AHR. Together, these data suggest that once airway inflammation develops, neutralizing the effects of IL-5 or reducing eosinophilia alone may not result in inhibiting established AHR in atopic asthma.

Allergens↗

PubMed1999

CD28 interactions with either CD80 or CD86 are sufficient to induce allergic airway inflammation in mice.

Previous studies have shown that the pan CD28/cytotoxic T lymphocyte antigen (CTL)A-4 antagonist CTLA4 immunoglobulin (Ig) inhibits eosinophilic airway inflammation in Schistosoma mansoni-sensitized and airway-challenged mice. In the present study, the importance of CD28 as well as the individual roles of CD80 and CD86 were examined in this system using wild-type and CD28 knockout (KO) mice. Unlike wild-type controls, CD28KO mice did not produce systemic IgE or eosinophilic airway inflammation after antigen challenge. However, a lymphocytic infiltrate and continued production of interferon-gamma was observed in these animals. Thus, CD28 is not essential for the initial recruitment of lymphocytes into antigen-challenged airways but critically regulates the allergic T-helper 2 phenotype. We next determined by polymerase chain reaction and flow cytometry that CD80 and CD86 molecules are constitutively expressed in the naive murine lung and on eosinophils in the allergic lung, suggesting a potential important role for both ligands in the development of asthma. Combined anti-CD80/anti-CD86 treatment throughout the antigen challenge period fully blocked the development of allergic airways, whereas a partial reduction was observed in mice treated with either anti-CD80 or anti-CD86 antibody alone. However, only anti-CD86 blocked systemic IgE production. Therefore, signaling through either CD80 or CD86 is sufficient to generate a partial local allergic response, whereas CD86 costimulation is essential to induce systemic allergic (IgE) reactions. Finally, combined anti-B7 monoclonal antibody treatment after sensitization reduced airway eosinophilia and interleukin (IL)-4/IL-5 cytokine secretion consistent with an ongoing role for CD28/B7 interactions in the effector phase of the disease. These results emphasize the importance of differential B7 expression on different cells and in different organs on subsequent CD28/B7-mediated immune events, including the potential for CD28/B7 blockade in the treatment of atopic airway disease in people.

Animals↗

PubMed1999

The protein phosphatase inhibitor cantharidin induces head and foot formation in buds of Cassiopea andromeda (Rhizostomae, Scyphozoa).

The polyps of Cassiopea andromeda produce spindle shaped, freely swimming buds which do not develop a head (a mouth opening surrounded by tentacles) and a foot (a sticky plate at the opposite end) until settlement to a suited substrate. The buds, therewith, look very similar to the planula larvae produced in sexual reproduction. With respect to both, buds and planulae, several peptides and the phorbolester TPA have been found to induce the transformation into a polyp. Here it is shown that cantharidin, a serine/threonine protein phosphatase inhibitor, induces head and foot formation in buds very efficiently in a 30 min treatment, the shortest yet known efficient treatment. Some resultant polyps show malformations which indicate that a bud is ordinary polyp tissue in which preparatory steps of head and foot formation mutually block each other from proceeding. Various compounds related to the transfer of methyl groups have been shown to affect head and foot formation in larvae of the hydrozoon Hydractinia echinata. These compounds including methionine, homocysteine, trigonelline, nicotinic acid and cycloleucine are shown to also interfere with the initiation of the processes which finally lead to head and foot formation in buds of Cassiopea andromeda.

Alkaloids↗