Search PubMed⌕ Search

Biomedical subjects

H Schultz

Publications and source records attributed to H Schultz.

At least 37 records · Page 2Linked to original sources
PubMed1997

Use of native and recombinant bactericidal/permeability-increasing proteins (BPI) as antigens for detection of BPI-ANCA.

Anti-neutrophil cytoplasmic antibodies (ANCA) against native bactericidal/permeability-increasing protein (nBPI) have gained increasing diagnostic significance in inflammatory bowel disease and cystic fibrosis. However, routine detection of BPI-ANCA requires pure antigen in large quantities. As nBPI is difficult to isolate and is very susceptible to proteolytic cleavage with subsequent epitope loss, it was the aim of this study to determine whether recombinant BPI (rBPI) can be used as an alternative to nBPI as target antigen for ANCA in diagnostic procedures. Therefore, 93 BPI-ELISA-positive sera and controls were compared in different ELISAs using nBPI, rBPI, unglycosylated rBPI and a 21-kDa amino-terminal fragment of rBPI. ELISA results were confirmed by immunoblotting and all sera were tested in indirect immunofluorescence (IFT). There was an 88% (82/93) agreement in recognition of nBPI and rBPI by ANCA in both ELISA systems, yet the quantitation of BPI-ANCA in relative units showed a less optimal result and correlated only by 45% (p < 0.01). Most sera recognized nBPI, rBPI and unglycosylated rBPI equally suggesting that glycosylation has no influence on antigen recognition. Only two sera were positive for the 21-kDa nBPI indicating that the binding sites for ANCA are either conformational epitopes and/or are located mainly on the carboxy-terminal part of the BPI molecule. Most BPI-ELISA-positive sera were negative in IFT (43%), but a perinuclear (pANCA, 30%), a cytoplasmic (cANCA,10%) or an atypical ANCA (aANCA, 2%) staining pattern, as well as a cytoplasmic pattern only on formaldehyde-fixed granulocytes (13%) were also observed. Overall, no characteristic pattern was seen for BPI-ELISA-positive sera in IFT. Taken together, these data suggest that rBPI offers an excellent alternative to nBPI for broad-based BPI-ANCA ELISA and will be of great value in further investigations of BPI-ANCA interactions.

Animals↗
PubMed1997

PMA-induced activation of the p42/44ERK- and p38RK-MAP kinase cascades in HL-60 cells is PKC dependent but not essential for differentiation to the macrophage-like phenotype.

The signaling mechanisms leading to phorbol ester myristate (PMA)-induced differentiation of HL-60 cells to the macrophagelike phenotype were investigated by using different protein kinase inhibitors. The protein kinase C inhibitor Ro 31-8220 specifically blocks PMA-induced differentiation, activation of the p42/44ERK- and p38RK-MAP kinase cascades and Hsp27-phosphorylation in HL-60 cells. Because Ro 31-8220 does not inhibit activation of the MAP kinase cascades by protein kinase C (PKC)-independent signals such as epidermal growth factor (EGF), heat shock, or anisomycin in these cells, only PMA-induced activation of the MAP kinases can be downstream of PKC. The MEK1 inhibitor PD 098059 and the p38RK inhibitor SB 203580 also were used to analyze whether the PMA-induced PKC-dependent activation of MAP kinases is involved in the differentiation process. Under certain conditions, PD 098059 can completely block the PMA-induced activation of the p42ERK as monitored by immunoprecipitation kinase assay by using the substrate myelin basic protein. SB 203580 specifically inhibits activation of p38RK as judged by MAPKAP kinase 2 activity against the substrate Hsp27 and also blocks Hsp27 phosphorylation in the cells. In contrast, neither PD 098059 nor SB 203580 nor both inhibitors together prevent PMA-induced differentiation of the HL-60 cells to the macrophagelike phenotype. The results suggest the existence of a diversification of PMA-induced signaling in HL-60 cells downstream of PKC, leading to activation of MAP kinases that are not essential for differentiation and to phosphorylation of other, so far unidentified, targets responsible for differentiation.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Conditional repression of the E2 transcription unit in E1-E3-deleted adenovirus vectors is correlated with a strong reduction in viral DNA replication and late gene expression in vitro.

An E1-E3-deleted recombinant adenovirus vector expressing the hybrid protein TetR-KRAB has been produced. In this virus, AdTG9562, the E2 transcription is regulated by TetR-KRAB and tetO sequences inserted in cis. In the absence of tetracycline, a strong reduction in E2A gene expression, viral DNA replication, and late gene expression was observed in noncomplementing A549 cells, and a reduction in viral growth was seen in the E1-expressing 293 cells. In contrast, there was no repression in the presence of the regulator tetracycline. We propose that regulation by TetR-KRAB is a valuable tool with which to study the effects of viral gene expression in vitro.

Adenoviridae↗
PubMed1997

The protein kinase inhibitor SB203580 uncouples PMA-induced differentiation of HL-60 cells from phosphorylation of Hsp27.

HL-60 cells are an attractive model for studies of human myeloid cell differentiation. Among the well-examined parameters correlated to differentiation of HL-60 cells are the expression and phosphorylation of the small heat shock protein Hsp27. Here we demonstrate that PMA treatment of HL-60 cells stimulates different MAP kinase cascades, leading to significant activation of ERK2 and p38 reactivating kinase (p38RK). Using the protein kinase inhibitor SB 203580, we specifically inhibited p38RK and, thereby, activation of its target MAP kinase-activated protein kinase 2 (MAPKAP kinase 2), which is the major enzyme responsible for small Hsp phosphorylation. As a result, PMA-induced Hsp27 phosphorylation is inhibited in SB 203580-treated HL-60 cells indicating that p38RK and MAPKAP kinase 2 are components of the PMA-induced signal transduction pathway leading to Hsp27 phosphorylation. We further demonstrate that, although PMA-induced phosphorylation is inhibited, SB 203580-treated HL-60 cells are still able to differentiate to the macrophage-like phenotype as judged by decrease in cell proliferation, induction of expression of the cell surface antigen CD11b and changes in cell morphology. These results indicate that, although correlated, Hsp27 phosphorylation is not required for HL-60 cell differentiation. However, the results do not exclude that increased Hsp27 expression is involved in HL-60 cell differentiation.

Antigens, Surface↗
PubMed1996

The Saudi experience with neutron therapy in locally advanced head and neck cancers.

The neutron therapy program at King Faisal Specialist Hospital and Research Center conducted a phase II study to evaluate the toxicity and efficacy of neutrons against conventional external megavoltage irradiation in patients with locally advanced head and neck malignancy. One hundred and nineteen patients were allocated to receive either photons (46/119) or neutrons (73/119). Radiation effects were scored according to the EORTC/RTOG criteria; data was collected weekly during treatment, once a month for the first year and at 6-month intervals subsequently. While acute effects were scored in all patients, only 59 were evaluable for late effects and locoregional control. A composite of the average reaction results were obtained using this information, to compare them in time, for acute and late effects in both arms of the study. The maximum acute reactions in the two groups were similar. In the majority of the patients (80%) acute skin and mucosal reactions occurred during the last week of treatment. The changes in the subcutaneous tissues and salivary glands became clinically apparent at 3 months or later. Salivary gland toxicity was more severe in the photon arm and the difference was statistically significant at 3 months (P = 0.04) but this was lost at 12 months. Late effects for skin and subcutaneous tissues were significantly more severe in the neutron arm with P values of 0.04 and 0.01 respectively. Three patients in the neutron arm died of grade 4 radiation complications. The local control and survival were similar in both groups.

Carcinoma, Squamous Cell↗
PubMed1996

The superantigen Staphylococcus enterotoxin B induces a strong and accelerated secondary T-cell response rather than anergy.

The primary and secondary immune response of V beta 8+ T cells to the bacterial superantigen Staphylococcus enterotoxin B was compared in BALB/c mice. Secondary responder T cells were found to up-regulate the expression of the adhesion molecule LFA-1 faster, and to enter the cell cycle earlier than primary responder T cells. Both, primary and secondary responder T cells upregulate the expression of CD2 and CD25 and turn into blast cells with superimposable time kinetics. Secondary responder T cells terminate DNA synthesis, blast formation and the upregulation of CD25 and CD2 expression earlier than primary responder T cells and become more rapidly deleted. Two days after superantigen challenge, when primary responder T cells reach peak activity in terms of DNA synthesis and blast formation, secondary responder T cells have returned to the size of microblasts and ceased to replicate their DNA. Whereas our results are consistent with the observations leading to the concept of superantigen-induced T-cell anergy, they demonstrate, by revealing the accelerated vigorous secondary T-cell response to the superantigen, that this concept requires reconsideration.

Animals↗
PubMed1996

Targeting cell-specific gene expression with an adenovirus vector containing the lacZ gene under the control of the CFTR promoter.

In vivo gene therapy requires the development of vectors able to deliver and express therapeutic genes preferentially into specific cell populations. This can be achieved by the manipulation of viral proteins mediating target-cell recognition, as well as by the introduction of tissue-specific promoters into viral vectors. As a first approach towards this goal, we describe here the construction and testing of a recombinant adenovirus expressing the lacZ gene encoding beta-galactosidase under the control of 2 kilobase pairs (kbp) of 5' untranslated DNA sequences of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. We show that such a recombinant virus directs beta-galactosidase expression in cell lines expressing CFTR, and in human and murine respiratory tract cells in vitro and in vivo. However, we were unable to demonstrate a cell-type specificity of expression strictly paralleling that of the endogenous CFTR gene. This data indicates that only part of the natural CFTR gene regulation is reconstituted in such a vector.

3T3 Cells↗
PubMed1995

Constitutive activation of mitogen-activated protein kinase-activated protein kinase 2 by mutation of phosphorylation sites and an A-helix motif.

A recently described downstream target of mitogen-activated protein kinases (MAPKs) is the MAPK-activated protein (MAPKAP) kinase 2 which has been shown to be responsible for small heat shock protein phosphorylation. We have analyzed the mechanism of MAPKAP kinase 2 activation by MAPK phosphorylation using a recombinant MAPKAP kinase 2-fusion protein, p44MAPK and p38/40MAPK in vitro and using an epitope-tagged MAPKAP kinase 2 in heat-shocked NIH 3T3 cells. It is demonstrated that, in addition to the known phosphorylation of the threonine residue carboxyl-terminal to the catalytic domain, Thr-317, activation of MAPKAP kinase 2 in vitro and in vivo is dependent on phosphorylation of a second threonine residue, Thr-205, which is located within the catalytic domain and which is highly conserved in several protein kinases. Constitutive activation of MAPKAP kinase 2 is obtained by replacement of both of these threonine residues by glutamic acid. A constitutively active form of MAPKAP kinase 2 is also obtained by deletion of a carboxyl-terminal region containing Thr-317 and the A-helix motif or by replacing the conserved residues of the A-helix. These data suggest a dual mechanism of MAPKAP kinase 2 activation by phosphorylation of Thr-205 inside the catalytic domain and by phosphorylation of Thr-317 outside the catalytic domain involving an autoinhibitory A-helix motif.

3T3 Cells↗
PubMed1995

Aerosol-mediated delivery of recombinant adenovirus to the airways of nonhuman primates.

At present, it is conceivable that gene therapy of the cystic fibrosis airway epithelium is possible using the direct transfer of a functional human cystic fibrosis transmembrane conductance regulator (CFTR) gene to a wide variety of patients' tracheo-bronchial cells. Here we describe a novel approach (aerosolization) to deliver a replication-deficient adenovirus carrying the CFTR gene (Ad.CFTR) to the airways. Results obtained in vitro and in Rhesus monkeys suggest that the delivery of recombinant adenovirus as an aerosol is feasible and is not associated with severe toxicity after single or double administration depending on the Ad.CFTR dose. This study supports the concept of aerosolization as a delivery method for adenovirus-mediated lung gene therapy.

Adenoviridae↗
PubMed1995

Trans-complementation of E1-deleted adenovirus: a new vector to reduce the possibility of codissemination of wild-type and recombinant adenoviruses.

Treatment of cystic fibrosis by gene therapy will require the development of vectors capable of efficient and safe transfer of a functional cystic fibrosis transmembrane conductance regulator (CFTR) cDNA to airway epithelia. To achieve this goal, replication-deficient (E1-) adenoviruses (Ad) are promising vectors. We have previously demonstrated efficient CFTR gene delivery to the airways of cotton rats and rhesus monkeys using a replication-deficient adenovirus, Ad-CFTR. Here, we have investigated an important safety issue, the interaction between the vector and wild-type virus which can provide the missing E1 function in trans. We show that Ad5 can mobilize the defective Ad-CFTR genome in vitro and in cotton rats. However, the extent of the complementation in vivo by wild-type virus is limited because no additional spreading or shedding of Ad-CFTR to trachea, lungs, and stools is elicited. To attenuate Ad-CFTR further, a mutation was introduced in the cis-acting regulatory sequences that control the encapsidation of the viral genome. We demonstrate that when cells are coinfected with wild-type virus and the new attenuated vector, the viral DNA containing the natural encapsidation sequences is preferentially packaged, leading to a rapid dilution of the recombinant virus.

Adenoviridae↗
PubMed1994

Activation of human T cells by the superantigen Staphylococcus enterotoxin B: analysis on a cellular level.

Superantigens interact with and activate a sizeable fraction of T cells characterized by expression of specific V beta gene segments of their antigen receptor. The massive activation of T cells in an organism is considered responsible for clinical symptoms associated with superantigen-producing bacteria. Here we studied the in vitro activation of human T cells by the superantigen Staphylococcus Enterotoxin B on a cell by cell basis. Superantigen-reactive T cells were stained with a V beta 12-specific monoclonal antibody and analyzed in a cytofluorograph. Blast formation of SEB-reactive T cells occurs within 12 h and reaches a plateau after 24 h. Double-staining of V beta 12+ T cells with antibodies against different T cell activation or adhesion surface molecules revealed a time-dependent differential upregulation for CD2, CD11 = LFA-1, CD25, CD28, CD69, and HLA-DR. The expression of CD3, CD4 and CD5 was not influenced by the superantigen. The rapid phenotypic changes of superantigen reactive T cells in terms of marker expression and cell size could provide early tools in diagnosing diseases caused by superantigens.

Antigens, CD↗
PubMed1994

In vivo adenovirus-mediated transfer of human CFTR cDNA to rhesus monkey airway epithelium: efficacy, toxicity and safety.

We have administered replication defective recombinant adenovirus harboring the human CFTR cDNA (Ad.CFTR) to lungs of Rhesus monkeys and assessed toxicity, efficiency of gene transfer and containment of recombinant adenovirus in the lungs. Gene transfer efficiencies, as measured by PCR analysis, were dose-dependent. Administration of low dose Ad.CFTR [1.5 x 10(7) plaque forming units (p.f.u.)] was not accompanied by any clinical chemical or histopathological changes. Mild to moderate multifocal perivascular and peribronchial lymphocytic infiltrates were found upon histopathological analysis only after administration of a high dose of recombinant adenovirus, although not accompanied by changes in clinical chemical parameters. Long-term expression (up to 128 days) was found after administration of recombinant adenovirus. Re-challenging of the monkeys treated with high-dose recombinant adenovirus resulted again in gene transfer at all levels of lungs and airways, without being accompanied by additional histopathological changes. Circulating anti-adenovirus antibodies were elicited. Animals treated with high-dose adenovirus secreted virus in pharynx and faeces for maximally 2 and 4 days after administration, respectively. These results show that recombinant adenovirus can be used for efficient delivery of genes into primate airway epithelium without signs of severe toxicity.

Adenoviridae↗
PubMed1993

Surveillance following orchidectomy for stage I seminoma of the testis.

From 1985 to 1988, 261 unselected patients entered a nationwide Danish study of surveillance only for testicular seminoma stage I. The median follow-up time after orchidectomy was 48 months, range 6-67 months. 49 patients relapsed (19%). Sites of relapse were paraaortic lymph nodes in 41 patients, pelvic lymph nodes in 5, inguinal lymph nodes in 2 and lung metastases in 1 patient. The median time to relapse was 14 months, range 2-37 months. The 4-year relapse-free survival was 80%. 37 of the relapsing patients (76%) had radiotherapy as relapse treatment. Of these patients, 4 (11%) had a second relapse and received chemotherapy. 1 died of disseminated seminoma. Of the relapsing patients, 12 (24%) had chemotherapy as relapse treatment because of bulky (11 patients) or disseminated disease (1 patient). None of these patients have had a second relapse. However, 2 patients died of infection due to chemotherapy-induced neutropenia. Thus, there have been three seminoma-related deaths (1.1%). The testicular tumour size had an independent prognostic significance. The 4-year relapse-free survivals were 94, 82 and 64% for tumours < 3, 3 to < 6 and > or = 6 cm, respectively. Patients with tumours > or = 6 cm will now be given prophylactic radiation treatment, whereas we will continue to use surveillance only after orchidectomy for patients with tumours < 6 cm.

Adult↗
PubMed1993

Characterization of anergy to the superantigen Staphylococcus enterotoxin B.

In vivo administration of superantigens leads to activation and subsequent depletion or anergy of T cells expressing defined V beta-T cell receptors (TCR). Superantigens have therefore become intensively studied tools for examining parameters of immunoregulation and they may represent model antigens for pathogenic agents. An HIV-encoded superantigen has for example been implicated in the dramatic loss of helper T cells in AIDS. We investigated the response of V beta 8+ T cells in mice after primary and secondary exposure to the superantigen Staphylococcus Enterotoxin B (SEB).

Animals↗
PubMed1993

[Effect of cholelithiasis and cholecystectomy on duodenogastric biliary reflux].

The aim of this work was to study the influence of cholelithiasis and cholecystectomy on duodenogastric biliary reflux. Total bile acid concentration (TBAC) in fasting gastric juice was measured in 23 consecutive patients with cholelithiasis and functioning gallbladder before and at least 3 months after cholecystectomy (group 1) and in 14 healthy volunteers (group II). In group two, TBAC was 8.5 +/- 2.8 uMol/l (mean +/- sem), the preoperative value in group I was 32.8 +/- 8.9 uMol/l and the postoperative value 69.9 +/- 14 uMol/l (p < 0.002 compared with group II and < 0.035 compared with preoperative values). These results suggest that cholelithiasis, even with a functioning gallbladder is associated with a significant increase in bile reflux to the stomach, with raises further after cholecystectomy.

Adult↗
PubMed1993

Thermal artifacts and inter-gynecologist variation of laser cone biopsies of the cervix.

OBJECTIVE: To evaluate the extent of thermal artifacts and the inter-gynecologist variation in CO2 laser cone biopsies for cervical intraepithelial neoplasia (CIN) using high power density. METHODS: All 1180 histologic sections from 93 CO2 laser cone biopsies performed by nine gynecologists were evaluated by morphometry. Power density of 19,700 W/cm2 and spot size of 0.43 mm were used. The lengths of different epithelia, the distance from CIN to the excision margins, the thermal artifacts, and the extension of denudation were analyzed. Mean values and standard deviations were analyzed for all indices. The inter-gynecologist variation was analyzed using one-way analysis of variance, Tukey-Kramer Honestly Significant Difference test, and chi 2 contingency table analysis regarding cones classified as "good" or "not good". RESULTS: The mean length of analyzed surface per cone was 134 mm. In 3% of the sections, the sum of artifacts at the external excision margin exceeded the average "minimum free distance" from CIN to the margin (2.88 mm). At the endocervical excision margin, the free distance was exceeded in 17% of the sections. Eighteen percent of the cones had CIN at the excision margins, with no significant differences between gynecologists (P = .83). Differences existed between gynecologists regarding free minimum distance and minor thermal artifacts at the external margin, but when clinically relevant groups were applied, no significant differences were found (P > .05). CONCLUSION: We found that a high power density at CO2 laser cone biopsy resulted in specimens with minimal thermal artifacts compared to other authors who used low power density. No clinically relevant differences were found between the gynecologists regarding free margins or artifacts.

Adult↗
PubMed1993

[Perinatal herpes infection. Clinical aspects--therapy--follow-up].

Herpes simplex virus may cause serious infections in neonates. In case of foetal infection in the first trimenon, abortions, stillbirth, prematurity, intrauterine growth retardation (not obligatory) and various malformations may result. Neonatal HSV infection is mostly the consequence of intrapartum virus acquisition during passage through the birth canal. The infection is mostly localised on the skin, at the eyes or the mouth or disseminated with or without HSV meningoencephalitis. It is difficult to establish the diagnosis, because neonatal herpes disease in the early stage is not easy to distinguish from other diseases in the newborn such as RDS, NEC or ICH. Antiviral therapy with aciclovir is the treatment of choice and seems to improve the outcome of neonatal herpes. Prognosis depends on early therapy. Treatment should be initiated in relation to clinical findings, because available diagnostic techniques do not always permit an early detection of the disease.

Acyclovir↗