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Biomedical subjects

J Gerdes

Publications and source records attributed to J Gerdes.

At least 73 records · Page 4Linked to original sources
PubMed1995

Severe retinopathy of prematurity in infants with birth weights less than 1250 grams: incidence and outcome of treatment with pharmacologic serum levels of vitamin E in addition to cryotherapy from 1985 to 1991.

OBJECTIVE: To determine the effect of vitamin E prophylaxis and treatment on the sequelae of severe (threshold) retinopathy of prematurity (ROP) in infants treated with cryotherapy at Pennsylvania Hospital from 1985 to 1991. STUDY DESIGN: Beginning on day 0, all infants with birth weights < or = 1250 gm received supplements of vitamin E using standard preparations. Serum E levels of 23 to 58 mumol/L (1 to 2.5 mg/dl) were targeted for infants with immature retinal vasculature or ROP of stage 2 or less in severity, and levels of 58 to 81 mumol/L (2.5 to 3.5 mg/dl) for infants with prethreshold ROP. At diagnosis of threshold ROP, treatment with a parenteral investigational new drug preparation of alpha-tocopherol was begun to raise serum levels to the pharmacologic range (93 to 116 mumol/L or 4 to 5 mg/dl). Within 3 days of diagnosis, and at the discretion of the retinal specialist, one or both eyes were treated with cryotherapy. Visual outcome at 4 years was compared with the 42-month outcome reported for eyes in the infants randomly assigned to treatment in the 1986-1987 Multicenter Trial of Cryotherapy for ROP (CRYO-ROP). RESULTS: Threshold ROP developed in 22 of 450 surviving infants (age 3 months). All were treated with pharmacologic serum levels of vitamin E; 17 infants were also treated with cryotherapy (10 in one eye and 7 in both eyes). These 17 infants, in comparison with infants in the CRYO-ROP trial (n = 187), were at least at equal risk for poor visual outcome on the basis of birth weight, gestational age, the percentage of zone 1 ROP, and mean interval from appearance of ROP to diagnosis of prethreshold ROP, which was shorter at Pennsylvania Hospital (4.1 days for the Pennsylvania Hospital group, 10.3 days for the CRYO-ROP group). However, on the basis of the mean number of days from diagnosis of prethreshold to threshold ROP (12.5 days for Pennsylvania Hospital, 10.5 days for CRYO-ROP) and the extent of extraretinal neovascularization at threshold (mean 7.9 sectors for Pennsylvania Hospital, 9.7 for CRYO-ROP), progression of retinopathy beyond the prethreshold stage had slowed and visual outcome in the eyes of infants at Pennsylvania Hospital treated with both cryotherapy and vitamin E (worse eye used for those treated with bilateral cryotherapy) was better than that reported for the treated eye of infants in the CRYO-ROP group (percentage of favorable visual acuity, 76% vs 48%, p = 0.04; percentage of normal structure posterior retinal pole, 71% vs 38%, p < or = 0.02). CONCLUSIONS: In this small case series, the combination of cryotherapy with anti-oxidant prophylaxis and treatment appeared to decrease the severity and sequelae of threshold ROP. This hypothesis deserves testing in a large, randomized clinical trial.

Combined Modality Therapy↗
PubMed1995

Double-blind, randomized trial of one versus three prophylactic doses of synthetic surfactant in 826 neonates weighing 700 to 1100 grams: effects on mortality rate. American Exosurf Neonatal Study Groups I and IIa.

At 33 hospitals in the United States, a double-blind, randomized clinical trial was performed to compare one versus three prophylactic doses of synthetic surfactant in 700 to 1100 gm inborn infants. All 826 infants received an initial prophylactic dose of surfactant within 30 minutes of birth. Subsequently 410 infants received two doses of placebo (air) 12 and 24 hours later, and 416 infants received two additional doses of surfactant. By the age of 28 days, 70 infants who received one dose of surfactant and 40 infants who received three doses were dead, a 43% relative reduction in the mortality rate (30 fewer deaths; p = 0.002). By the age of 1 year after term, 87 infants who received one dose and 62 infants who received three doses were dead: a 29% relative reduction in the mortality rate (25 fewer deaths; p = 0.027). Infants who received three doses of surfactant required significantly less oxygen and less mean airway pressure for the first week of life. Necrotizing enterocolitis (9 vs 25 infants; p = 0.005), and use of high-frequency ventilation (13 vs 26 infants; p = 0.037); pancuronium (43 vs 62 infants; p = 0.045); and leukocyte transfusions (0 vs 4 infants; p = 0.042) were less frequent in the three-dose group, but air leak, bronchopulmonary dysplasia, intraventricular hemorrhage, patent ductus arteriosus, pulmonary hemorrhage, and infections were not different. These results indicate that physiologic findings, mortality rates, and probably morbidity rates are improved by two additional prophylactic doses of synthetic surfactant.

Bronchopulmonary Dysplasia↗
PubMed1995

Presence of mRNA for interferon-gamma (IFN-gamma) in blood mononuclear cells is associated with an active stage I sarcoidosis.

Peripheral blood mononuclear cells (PBMC) and bronchoalveolar lavage (BAL) cells obtained from sarcoidosis patients were investigated for the presence of mRNA for IFN-gamma. RNA was extracted from freshly obtained cells. In 12 cases PBMC were studied and in seven cases BAL cells were also available for concomitant investigation. In eight patients mRNA for IFN-gamma was present in blood and was significantly associated with stage I disease (P = 0.030). By comparison, BAL cells were less frequently positive for IFN-gamma transcripts (P = 0.039). Only one patient had simultaneous expression of IFN-gamma gene in blood and BAL cells. All other patients including four positive in blood were negative in BAL. The presence of IFN-gamma transcripts in PBMC was significantly associated with the capacity of these cells to generate IFN-gamma in unstimulated cultures. PBMC from patients showing IFN-gamma mRNA in blood were frequently high IFN-gamma producers in anti-CD3 MoAb-stimulated cultures.

Adult↗
PubMed1995

CD26 expression in leprosy and other granulomatous diseases correlates with the production of interferon-gamma.

BACKGROUND: Leprosy represents a spectrum of clinical manifestations that reflect the immune response to antigens of Mycobacterium leprae. The tuberculoid form of leprosy, which is characterized by an organized development of granulomas, has recently been correlated with a Th1-like immune response. The lepromatous form of leprosy, with a characteristic lack of cellular immunity, has been correlated with a Th2-like immune response to mycobacterial antigens. Dipeptidylpeptidase IV (CD26) is an ectopeptidase that is expressed in various tissues; in the hemopoietic system, it is predominantly expressed by T cells. EXPERIMENTAL DESIGN: We stained frozen sections of skin biopsies obtained from patients with different forms of leprosy, sarcoidosis, and Piringer's lymphadenitis. Sections were stained for interferon-gamma (IFN-gamma) and CD26 with the alkaline phosphatase anti-alkaline phosphatase technique and in two-color stainings by immunofluorescence. RESULTS: We found strong signals for IFN-gamma and for CD26 in all investigated cases of tuberculoid leprosy. In contrast, in all biopsies taken from patients with lepromatous leprosy, we found no or very weak signals for these antigens. By immunofluorescence double-labeling, we could show that IFN-gamma and CD26 were expressed by the identical cell population. We confirmed this correlation of CD26 expression and IFN-gamma production in other granulomatous inflammatory reactions such as sarcoidosis and Piringer's lymphadenitis. CONCLUSIONS: From our results, we conclude that a high expression of CD26 may be suggestive of Th1-like immune reactions.

Dipeptidyl Peptidase 4↗
PubMed1995

Development of renal podocytes cultured under medium perifusion.

BACKGROUND: In the past, podocytes have been described as highly susceptible to dedifferentiation under cell culture. Whether this process resulted from insufficient culture conditions or whether it was a consequence of missing cellular interactions remained unclear. A further reason could be that podocytes within the maturing kidney are irreversibly growth-arrested at a very early point of development because proliferating cells have been detected at the S-shaped body stage but not at the capillary loop stage or in the maturing glomeruli. These were important reasons that hindered the establishment of podocyte cell culture systems. EXPERIMENTAL DESIGN: The aim of our present study was to culture podocytes under the most organotypic conditions possible to maintain typical cellular characteristics. Cortex explants of neonatal rabbit kidneys consisting of nephrogenic tissue were used as a source for podocytes. No serum additives were given for the whole culture period of 13 days. An organ-specific environment was obtained by keeping the podocytes within the surrounding renal tissue and by ensuring a permanent exchange of medium. RESULTS: mAb were used to characterize podocytes and the other glomerular cell types. Cultured podocytes and parietal cells of Bowman's capsule were identified by EnPo 1. Ks 19.2.105, a marker for cytokeratin 19, was used to discriminate among these epithelial cells because cytokeratin 19 is expressed by the parietal cells of Bowman's capsule but not by podocytes. The Ab EC1 specifically detected endothelial cells. Glomerular endothelium cultured under medium perifusion expressed these typical Ag and thus could be unequivocally discriminated. Furthermore, by means of the proliferation marker Ki-67, it could be demonstrated that glomerulus-like structures developed under culture by proliferation of visceral and parietal cells of Bowman's capsule. CONCLUSIONS: A culture model is presented that allows the maintenance of developing podocytes within the organ-specific tissue environment and under permanent medium perifusion.

Animals↗
PubMed1995

Cell proliferation-associated nuclear antigen defined by antibody Ki-67: a new kind of cell cycle-maintaining proteins.

A decade of studies on the human nuclear antigen defined by monoclonal antibody Ki-67 (the "Ki-67 protein") has made it abundantly clear that this structure is strictly associated with human cell proliferation and that the expression of this protein can be used to assess the growth fraction of a given cell population. Until recently the Ki-67 protein was described as a nonhistone protein that is highly susceptible to protease treatment. We have isolated and sequenced cDNAs encoding for this antigen and found two isoforms of the full length cDNA of 11.5 and 12.5 kb, respectively, sequence and structure of which are thus far unique. The gene encoding the Ki-67 protein is organized in 15 exons and is localized on chromosome 10. The center of this gene is formed by an extraordinary 6845 bp exon containing 16 successively repeated homologous segments of 366 bp ("Ki-67 repeats"), each containing a highly conserved new motif of 66 bp ("Ki-67 motif"). The deduced peptide sequence of this central exon possess 10 ProGluSerThr (PEST) motifs which are associated with high turnover proteins such as other cell cycle-related proteins, oncogenes and transcription factors, etc. Like the latter proteins the Ki-67 antigen plays a pivotal role in maintaining cell proliferation because Ki-67 protein antisense oligonucleotides significantly inhibit 3H-thymidine incorporation in permanent human tumor cell lines in a dose-dependent manner.

Amino Acid Sequence↗
PubMed1994

Assessment of cell proliferation by means of an enzyme-linked immunosorbent assay based on the detection of the Ki-67 protein.

A new ELISA system for the estimation of cell proliferation based on the detection of the Ki-67 protein is described. This protein has turned out to be strictly correlated to all active parts of the cell cycle, i.e., G1, S, G2, and mitosis, but is absent in G0. In addition, it is not detectable during DNA repair. In cultures of cell line cells as well as stimulated peripheral blood cells the values obtained with this ELISA system paralleled the [3H]thymidine uptake in different cell cultures. Thus, this assay provides a simple, non-radioactive assessment of proliferation of cultured cells.

Animals↗
PubMed1994

Detection of Mycobacterium leprae by three-primer PCR.

Recently, polymerase chain reaction has been introduced for the species-specific assessment of Mycobacterium leprae (1). To avoid Southern blotting techniques using radioactively labelled oligonucleotide probes, the aim of this study was to establish a three primer-based single-step PCR technique. Using primers designed for this purpose we amplified a part of the gene encoding for the 16S ribosomal RNA of slowly growing mycobacteria. Due to the species-specific antisense primer a second, smaller fragment specific for M. leprae was amplified. Our results show that the employment of a second antisense primer in the PCR may be a substitution for Southern blot hybridization.

Base Sequence↗
PubMed1994

Mycobacterium leprae DNA content, cellular and cytokine patterns in skin lesions of leprosy patients undergoing multidrug therapy (MDT).

Skin biopsies from untreated and MDT-treated patients were examined for infiltrating cells and cells producing the cytokines TNF-alpha, IFN-gamma, and IL-1 beta using immunohistochemistry. Biopsy specimens from untreated tuberculoid leprosy patients were characterized by the presence of cells producing TNF-alpha, IFN-gamma, and IL-1 beta and of subepidermal Langerhans cells. These cells were rarely found or completely absent in biopsies of untreated lepromatous leprosy patients, but tended to increase under MDT. In a short-term therapy trial for three months with brodimoprim, dapsone, and rifampicin, 12 patients were monitored by follow-up biopsies. Semiquantitative PCR for mycobacterial DNA revealed two groups of patients: one group in which mycobacterial DNA in follow-up biopsies remained constant and a second group in which a decrease of mycobacterial DNA during therapy was noted. Immunophenotyping in these follow-up biopsies revealed that in the latter group IFN-gamma-positive cells and Langerhans cells were present and gamma delta T cell receptor-positive cells tended to decrease during therapy. In contrast, in patients whose mycobacterial DNA did not change during therapy, these phenotypical manifestations were not observed. We therefore, conclude that assessment of mycobacterial DNA in combination with phenotyping of infiltrating cells and determination of cytokine patterns may be useful tools in establishing criteria for the effectiveness and duration of MDT in patients with leprosy.

Anti-Bacterial Agents↗
PubMed1994

IL-10 secretion of allergen-specific skin-derived T cells correlates positively with that of the Th2 cytokines IL-4 and IL-5.

In atopic individuals, allergen-specific CD4+ T lymphocytes often belong to the T-helper 2 (Th2) subset as they secrete the marker cytokines interleukin-4 (IL-4) and IL-5 but not interferon-gamma (INF-gamma). IL-10 is a cytokine the production of which, in the mouse system has been described to be restricted to the Th2 subset, but in the human was found to be produced by both Th1 and Th2 T cell clones (TCC). We have recently shown that house dust mite antigen (Dermatophagoides pteronyssinus)-specific TCC isolated from skin of patients with atopic dermatitis have a more polarized Th2 cytokine production profile than TCC obtained from the peripheral blood of these patients. In this study, we report that skin-derived TCC secrete more IL-10, IL-4 and IL-5, than TCC isolated from the blood of the same individual (p < 0.05). The difference was more significant with specific TCC than with non-specific TCC. Furthermore, there was a positive correlation between the production of IL-10 and that of IL-4 and IL-5, respectively. In addition, the amount of IL-4 and IL-5 secreted by specific TCC from the skin correlated positively. These results were confirmed by the detection of mRNA by PCR. Finally, our data confirm that in human blood-derived TCC IL-10 secretion is not related to a particular cytokine production profile. We suggest that the skin of AD provides an unique environment for the development of aTh2-like secretion pattern not only with respect to IL-4 and IL-5 but also regarding IL-10.

Allergens↗
PubMed1994

Epitope analysis of antibodies recognising the cell proliferation associated nuclear antigen previously defined by the antibody Ki-67 (Ki-67 protein).

AIMS--To elucidate the fine specificities of the antibodies MIB 1 and MIB 3 and of additional monoclonal antibodies which also recognise the Ki-67 protein (MIB 5, IND.64, JG-67-2a). METHODS--Different parts of the Ki-67 protein cDNA were expressed in Escherichia coli. Bacterial lysates were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and blotted on to nitrocellulose. Additionally different peptides were synthesised on a membrane support (SPOT-Blot). The immunoreactivity of the antibodies with the recombinant proteins and the immobilised synthetic peptides, respectively, was analysed. A competition enzyme linked immunosorbent assay (ELISA) using a soluble synthetic peptide was also performed. RESULTS--The epitopes of all antibodies tested were contained within the same region of seven amino acids. The antibodies MIB 1 and MIB 3 required the five amino acid sequence FKELF for binding, whereas Ki-67, JG-67-2a, MIB 5 and IND.64 detected the sequence FKEL. CONCLUSIONS--It is concluded that the amino acid sequence FKELF represents an immunodominant area of the Ki-67 protein and that there is no correlation between the ability to detect the Ki-67 protein in paraffin wax sections irradiated with microwaves and the epitopes recognised by the antibodies.

Amino Acid Sequence↗
PubMed1993

Comparison between the monoclonal antibodies Ki-67 and PC10 in 125 malignant lymphomas.

The monoclonal antibody (MAb) Ki-67 detects a nuclear proliferation-associated antigen which corresponds to a non-histone protein with a molecular weight of 395 and 345 kD. Its prognostic relevance has been assessed in both lymphoid and non-lymphoid tumours. The MAb PC10 picks up the proliferating cell nuclear antigen (PCNA), which is a 36 kD nuclear protein associated with the cell cycle. Whereas Ki-67 works only in fresh material, PC10 detects a fixation-resistant epitope of PCNA. Preliminary data have revealed a linear relationship between Ki-67 and PC10 reactivity in normal lymphoid tissue and in non-Hodgkin's lymphomas (NHLs). We applied Ki-67 and PC10 to frozen and routine sections, respectively, from 25 examples of Hodgkin's disease (HD) (14 nodular sclerosis, 6 lymphocyte predominance, 5 mixed cellularity) and 100 NHLs (corresponding to the main varieties of the updated Kiel classification). The results obtained can be summarized as follows: (1) both MAbs gave rise to extremely variable results within the same category of NHLs; (2) most Hodgkin and Reed-Sternberg cells (50-98 per cent) were labelled by the reagents; (3) Ki-67 and PC10 stained a similar ratio of neoplastic cells in 65 and 76 per cent of NHL and HD cases, respectively; in the remaining instances, no correspondence was observed, the PC10-positive elements usually outnumbering the Ki-67-positive ones significantly. These discrepancies, which might be due to low PCNA catabolism and/or PCNA expression by quiescent cells, underline the need for further kinetic and clinico-pathologic studies in order to define the specific relevance of PC10.

Antibodies, Monoclonal↗
PubMed1993

A majority of proliferating T cells in cutaneous malignant T cell lymphomas may lack the high affinity IL-2 receptor (CD25).

IL-2 is a major growth factor for all T-cell subsets acting via a specific membrane receptor. To investigate its role in the pathogenesis of cutaneous T-cell lymphomas (CTCLs), we analysed the expression of high-affinity IL-2 receptors (IL-2Rs) on proliferating cells in these disorders. We showed by immunohistochemical double staining that most cycling cells do not express high-affinity IL-2Rs. Four T-cell lines were established from patients with CTCLs. Two lines required both IL-2 and IL-4 for growth, one line required IL-2 and one line IL-4 alone. The last of these lacked expression of the IL-2R alpha-chain. Thus, IL-2 may not be the only, or the most important, growth stimulus in CTCLs and reactive skin infiltrates. T helper cells, which dominated the infiltrate, might represent TH2 cells.

Biomarkers↗
PubMed1993

Enzootic Mycobacterium avium infection in captive Parma wallabies (Macropus parma) with unusual spinal cord manifestations.

Pathological, microbiological and clinical findings in Parma wallabies (Macropus parma) with an enzootic infection caused by Mycobacterium avium are described. Disorders of locomotion resulted from granulomatous myelitis, meningitis and radiculitis in the lumbosacral spinal cord. Lesions found in a number of internal organs suggested protracted systemic infection due to an alimentary or airborne infection with Mycobacterium avium. This organism was isolated and identified by methods that included microbiological examinations, based on microscopy, culture, in-vitro tests, animal inoculation, polymerase chain reaction and cycle sequencing.

Animals↗
PubMed1993

The cell proliferation-associated antigen of antibody Ki-67: a very large, ubiquitous nuclear protein with numerous repeated elements, representing a new kind of cell cycle-maintaining proteins.

The antigen defined by mAb Ki-67 is a human nuclear protein the expression of which is strictly associated with cell proliferation and which is widely used in routine pathology as a "proliferation marker" to measure the growth fraction of cells in human tumors. Ki-67 detects a double band with apparent molecular weights of 395 and 345 kD in immunoblots of proteins from proliferating cells. We cloned and sequenced the full length cDNA, identified two differentially spliced isoforms of mRNA with open reading frames of 9,768 and 8,688 bp encoding for this cell proliferation-associated protein with calculated molecular weights of 358,761 D and 319,508 D, respectively. New mAbs against a bacterially expressed part and a synthetic polypeptide deduced from the isolated cDNA react with the native Ki-67 antigen, thus providing a circle of evidence that we have cloned the authentic Ki-67 antigen cDNA. The central part of the Ki-67 antigen cDNA contains a large 6,845-bp exon with 16 tandemly repeated 366-bp elements, the "Ki-67 repeats", each including a highly conserved new motif of 66 bp, the "Ki-67 motif", which encodes for the epitope detected by Ki-67. Computer analysis of the nucleic acid and the deduced amino acid sequence of the Ki-67 antigen confirmed that the cDNA encodes for a nuclear and short-lived protein without any significant homology to known sequences. Ki-67 antigen-specific antisense oligonucleotides inhibit the proliferation of IM-9 cell line cells, indicating that the Ki-67 antigen may be an absolute requirement for maintaining cell proliferation. We conclude that the Ki-67 antigen defines a new category of cell cycle-associated nuclear nonhistone proteins.

Amino Acid Sequence↗