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Biomedical subjects

J D Kelly

Publications and source records attributed to J D Kelly.

At least 19 recordsLinked to original sources
PubMed2001

Platelet-derived growth factor C (PDGF-C), a novel growth factor that binds to PDGF alpha and beta receptor.

We have characterized platelet-derived growth factor (PDGF) C, a novel growth factor belonging to the PDGF family. PDGF-C is a multidomain protein with the N-terminal region homologous to the extracellular CUB domain of neuropilin-1, and the C-terminal region consists of a growth factor domain (GFD) with homology to vascular endothelial growth factor (25%) and PDGF A-chain (23%). A serum-sensitive cleavage site between the two domains allows release of the GFD from the CUB domain. Competition binding and immunoprecipitation studies on cells bearing both PDGF alpha and beta receptors reveal a high affinity binding of recombinant GFD (PDGF-CC) to PDGF receptor-alpha homodimers and PDGF receptor-alpha/beta heterodimers. PDGF-CC exhibits greater mitogenic potency than PDGF-AA and comparable or greater mitogenic activity than PDGF-AB and PDGF-BB on several mesenchymal cell types. Analysis of PDGF-CC in vivo in a diabetic mouse model of delayed wound healing showed that PDGF-CC significantly enhanced repair of a full-thickness skin excision. Together, these studies describe a third member of the PDGF family (PDGF-C) as a potent mitogen for cells of mesenchymal origin in in vitro and in vivo systems with a binding pattern similar to PDGF-AB.

Amino Acid Sequence↗
PubMed2001

Interleukin 20: discovery, receptor identification, and role in epidermal function.

A structural, profile-based algorithm was used to identify interleukin 20 (IL-20), a novel IL-10 homolog. Chromosomal localization of IL-20 led to the discovery of an IL-10 family cytokine cluster. Overexpression of IL-20 in transgenic (TG) mice causes neonatal lethality with skin abnormalities including aberrant epidermal differentiation. Recombinant IL-20 protein stimulates a signal transduction pathway through STAT3 in a keratinocyte cell line, demonstrating a direct action of this ligand. An IL-20 receptor was identified as a heterodimer of two orphan class II cytokine receptor subunits. Both receptor subunits are expressed in skin and are dramatically upregulated in psoriatic skin. Taken together, these results demonstrate a role in epidermal function and psoriasis for IL-20, a novel cytokine identified solely by bioinformatics analysis.

Animals↗
PubMed2001

Assessment of the endoscopic semitendinosus/gracilis autograft procedure with interference screw fixation for reconstruction of the anterior cruciate ligament.

The semitendinosus/gracilis autograft procedure with interference screw fixation was evaluated for clinical effectiveness of anterior cruciate ligament (ACL) reconstruction. Thirty patients underwent the procedure and were evaluated an average of 15 months postoperatively. Results revealed 22 (73%) patients had a standard knee evaluation form score of normal or nearly normal, and 24 (80%) patients returned to strenuous or moderate activity levels. Average Lysholm outcome score was 89, and bilateral KT-2000 differences were <3 mm at follow-up. Functional knee test symmetry index percentage outcome for the one-legged hop test was 92.6% for distance and 98% for time. Length of time (i.e., < or =90 days or > or =91 days) between injury and surgery was independent of outcome. These findings indicate the semitendinosus/gracilis autograft is a viable procedure for reconstruction of the ACL-deficient knee.

Adult↗
PubMed2001

The effect of antisense Bcl-2 oligonucleotides on Bcl-2 protein expression and apoptosis in human bladder transitional cell carcinoma.

PURPOSE: Bcl-2 is an important determinant of transitional cell carcinoma of the bladder recurrence and progression as well as a factor in patient response to chemotherapy or radiotherapy. We determined Bcl-2 down-regulation after antisense oligonucleotide therapy and synergism with mitomycin C in transitional cell carcinoma of the bladder. MATERIALS AND METHODS: Bcl-2 protein was quantified using flow cytometry and immunohistochemistry in 4 bladder cancer cell lines, in bladder washings from 6 patients with carcinoma in situ and in 16 patient tumor samples. The synergistic effects of antisense oligonucleotides G3139 and 2009, and mitomycin C were investigated in 4 cell lines, while 2009 down-regulation was examined in 20 tumor explants in an ex vivo model. RESULTS: Bcl-2 protein expression was found in all 4 cell lines and in 5 of the 6 cell populations derived from patients with carcinoma in situ. Of the 16 tumors 7 were classified positive by frozen section immunohistochemistry and quantitative flow cytometry. G3139 and 2009 down-regulated Bcl-2 protein expression in all 4 cell lines and 2009 down-regulated Bcl-2 protein expression in half of the Bcl-2 positive tumor specimens. There was only evidence in 1 cell line, T24/83, that Bcl-2 protein expression down-regulation enhanced mitomycin C induced apoptotic cell death. CONCLUSIONS: Bcl-2 was expressed in a significant proportion of bladder tumors and in carcinoma in situ. Therefore, antisense oligonucleotides represent a viable strategy for Bcl-2 protein down-regulation. However, it may not always translate into an increased level of mitomycin C induced apoptosis in transitional cell carcinoma of the bladder.

Apoptosis↗
PubMed2000

Testicular sperm extraction by Trucut needle and milking of seminiferous tubules: a technique with high yield and patient acceptability.

OBJECTIVE: To assess the sperm yield and patient acceptability of Trucut needle testicular biopsy followed by seminiferous tubule milking. DESIGN: Prospective case analysis. SETTING: The Regional Fertility Center, Royal Maternity Hospital, Belfast, Northern Ireland, United Kingdom. PATIENT(S): Forty-one males with obstructive azoospermia (normal testicular volume and FSH and LH levels). INTERVENTION(S): Trucut needle testicular biopsies under local anesthetic with milking of the seminiferous tubules. MAIN OUTCOME MEASURE(S): Quantitation of sperm retrieved per biopsy core and patient follow-up by questionnaire. RESULT(S): A mean of 105,634 sperm (range, 5,000-427,800) were retrieved, and the mean biopsy weight was 9.17 mg. Twenty-six subjects found the biopsy painless and 15 were pain-free after biopsy. CONCLUSION(S): The Trucut needle can be used in combination with seminiferous tubule milking to obtain large numbers of sperm in men with obstructive azoospermia.

Anesthesia, Local↗
PubMed2000

2S methionine-rich protein (SSA) from sunflower seed is an IgE-binding protein.

BACKGROUND: Sunflower seed contains 2S albumins that in other crops have been associated with allergenicity. The sunflower seed methionine-rich 2S albumin (SSA) may be an IgE-binding protein responsible for anaphylactic reactions in some sunflower seed-sensitive subjects. The objective was to demonstrate that SSA is an IgE-binding protein. METHODS: SSA was purified and the amino-acid sequence determined. The degree of purity of SSA was evaluated by silver staining, and its IgE-binding capacity by immunoblotting with serum from a subject with a convincing clinical history of anaphylaxis to sunflower seed. RESULTS: The amino-acid sequence confirmed that the purified protein was the mature form of the methionine-rich storage protein SSA from sunflower seed (Helianthus annuus). The SSA was specifically recognized by IgE from the serum of the sunflower seed-allergic subject. CONCLUSIONS: SSA is an IgE-binding protein, and subjects allergic to sunflower seed whose IgE binds to SSA are at risk of developing allergic reactions if they consume SSA.

2S Albumins, Plant↗
PubMed2000

Induction of apoptosis by mitomycin-C in an ex vivo model of bladder cancer.

OBJECTIVE: To examine mitomycin-C (MMC)-induced apoptosis in an ex vivo model of superficial TCC, and relate it to the in vivo response to chemotherapy. Materials and methods Dose- and time-response curves were constructed to determine the optimal conditions for the induction of apoptosis by MMC in an ex vivo model of superficial bladder cancer. Subsequently, 41 individual tumours were exposed to MMC in the model and the effects assessed by measuring of apoptosis before and after chemotherapy. The relationships between tumour grade and stage and the intrinsic and induced apoptotic counts were determined. In tandem, in a clinical study, the relationship between in vivo response of a marker tumour to MMC and the ex vivo induction of apoptosis was determined. RESULTS: In the ex vivo model, apoptosis was induced at a MMC concentration of 0.5 mg/mL after an incubation time of 8 h. In 41 tumours the intrinsic apoptotic index (AI) was higher with increased grade and stage of tumour (P = 0.048). There was no correlation between the intrinsic AI and the AI after treatment with MMC (induced AI). In 21 tumours (51%) the induced AI did not increase above a predetermined response threshold and these tumours were considered resistant to MMC. Resistance to MMC was related to tumour grade (P = 0.037) with a trend for G3 pT1 tumours to be resistant to the therapy. There was a significant association between ex vivo sensitivity and in vivo marker tumour response (P = 0.02). CONCLUSIONS: Apoptosis is differentially induced in an ex vivo incubation model of superficial TCC by MMC and evidence suggests that this response matches that seen in vivo. The measurement of apoptosis before therapy does not predict the apoptotic response of a tumour to chemotherapy. The ability to undergo apoptosis correlates with clinical outcome.

Antibiotics, Antineoplastic↗
PubMed2000

Identification of sunflower seed IgE-binding proteins.

BACKGROUND: Sunflower seed can cause severe anaphylactic reactions in some susceptible individuals. It is conceivable that the 2S sunflower seed protein is an allergen based on its high degree of homology (34%) with the allergenic mature 2S albumin protein of the Brazil nut. The first step in determining the allergenicity of sunflower seed proteins is to identify IgE-binding proteins. METHODS: Sera from sunflower seed-sensitive individuals were evaluated by radioallergosorbent test (RAST), isoelectric focusing (IEF) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting with sunflower seed proteins. RESULTS: Positive RAST scores (>2) were observed in 3 individuals and immunoblotting demonstrated IgE-binding to 2-7 distinct proteins ranging in size from 10 to 50 kD. Two out of 3 sera recognized two proteins between 16 and 17 kD. The lower molecular weight protein (16 kD) approximates to the prepo region of the precursor methionine-rich 2S albumin protein found in sunflower seed (SFA-8/SSA). IEF followed by immunoblotting demonstrated several IgE-binding proteins, including two proteins with isoelectric points of 5.97 and 5.3, respectively, which are consistent with the mature and immature forms of the SFA-8/SSA region. CONCLUSIONS: Sunflower seed contains several IgE-binding proteins, including regions of the high-methionine 2S albumin SFA-8/SSA.

2S Albumins, Plant↗
PubMed1999

Relationship between DNA methylation and mutational patterns induced by a sequence selective minor groove methylating agent.

Me-lex, a methyl sulfonate ester appended to a neutral N-methylpyrrolecarboxamide-based dipeptide, was synthesized to preferentially generate N3-methyladenine (3-MeA) adducts which are expected to be cytotoxic rather than mutagenic DNA lesions. In the present study, the sequence specificity for DNA alkylation by Me-lex was determined in the p53 cDNA through the conversion of the adducted sites into single strand breaks and sequencing gel analysis. In order to establish the mutagenic and lethal properties of Me-lex lesions, a yeast expression vector harboring the human wild-type p53 cDNA was treated in vitro with Me-lex, and transfected into a yeast strain containing the ADE2 gene regulated by a p53-responsive promoter. The results showed that: 1) more than 99% of the lesions induced by Me-lex are 3-MeA; 2) the co-addition of distamycin quantitatively inhibited methylation at all minor groove sites; 3) Me-lex selectively methylated A's that are in, or immediately adjacent to, the lex equilibrium binding sites; 4) all but 6 of the 33 independent mutations were base pair substitutions, the majority of which (17/33; 52%) were AT-targeted; 5) AT --> TA transversions were the predominant mutations observed (13/33; 39%); 6) 13 out of 33 (39%) independent mutations involved a single lex-binding site encompassing positions A600-602 and 9 occurred at position 602 which is a real Me-lex mutation hotspot (n = 9, p < 10(-6), Poisson's normal distribution). A hypothetical model for the interpretation of mutational events at this site is proposed. The present work is the first report on mutational properties of Me-lex. Our results suggest that 3-MeA is not only a cytotoxic but also a premutagenic lesion which exerts this unexpected property in a strict sequence-dependent manner.

Adenine↗
PubMed1998

99mTc-HL91: "hot spot" detection of ischemic myocardium in vivo by gamma camera imaging.

BACKGROUND: 99mTc-HL91 is a new hypoxia imaging agent that demonstrates increased uptake and retention in globally hypoxic myocardium in vitro. The purpose of this study was to determine whether 99mTc-HL91 could detect regional ischemia in vivo by gamma camera imaging. METHODS AND RESULTS: Eight open-chest dogs with left circumflex (LCx) stenoses were studied. Injection of 5 mCi of 99mTc-HL91 and microspheres was followed by imaging over 4 hours. Heart slices were imaged, then stained with triphenyltetrazolium chloride (TTC), and tissues were well-counted. TTC staining demonstrated no injury. Mean LCx blood flow was 0.32+/-0.04 mL x min(-1) x g(-1), and mean left anterior descending coronary artery (LAD) flow was 0.96+/-0.02 mL x min(-1) x g(-1) (ratio, 0.33). "Hot spots" were detected in 8 of 8 experiments in vivo within 60 minutes and improved over 4 hours. Region of interest analysis of LCx/LAD activity ratios demonstrated significant increases within 30 minutes (final ratio, 3.0; P<0.05). LCx and LAD washout curves demonstrated significant differences within 15 minutes. Washout curves were biexponential over 1 hour, followed by linear retention from 1 to 4 hours. Four-hour fractional retention was 0.12 for LAD and 0.44 for LCx (P<0.01). Myocardial flow versus tracer uptake demonstrated 2 phases: phase 1 (flow, 0.05 to 0.7 mL x min(-1) x g(-1)) had an inverse linear correlation (r= -0.80); phase 2, (flow, >0.7 mL x min(-1) x g(-1)) had no correlation. Ischemic heart/liver ratios remained near 1.0 for 4 hours. CONCLUSIONS: 99mTc-HL91 positively identifies regional myocardial ischemia in a canine model using 99mTc imaging. Quantitative techniques allowed identification of ischemic myocardium within 15 minutes of tracer administration.

Animals↗
PubMed1998

Signal transduction via the mitogen-activated protein kinase pathway induced by binding of coagulation factor VIIa to tissue factor.

The putative role of tissue factor (TF) as a receptor involved in signal transduction is indicated by its sequence homology to cytokine receptors (Bazan, J. F. (1990) Proc. Natl. Acad. Sci. U. S. A. 87, 6934-6938). Signal transduction induced by binding of FVIIa to cells expressing TF was studied with baby hamster kidney (BHK) cells stably transfected with TF and with a reporter gene construct encoding a luciferase gene under transcriptional control of tandem cassettes of signal transducer and activator of transcription (STAT) elements and one serum response element (SRE). FVIIa induced a significant luciferase response in cells expressing TF, BHK(+TF), but not in cells without TF. The BHK(+TF) cells responded to the addition of FVIIa in a dose-dependent manner, whereas no response was observed with active site-inhibited FVIIa, which also worked as an antagonist to FVIIa-induced signaling. Activation of the p44/42 MAPK pathway upon binding of FVIIa to TF was demonstrated by suppression of signaling with the specific kinase inhibitor PD98059 and demonstration of a transient p44/42 MAPK phosphorylation. No stimulation of p44/42 MAPK phosphorylation was observed with catalytically inactive FVIIa derivatives suggesting that the catalytic activity of FVIIa was obligatory for activation of the MAPK pathway. Signal transduction caused by a putative generation of FXa activity was excluded by experiments showing that FVIIa/TF-induced signaling was not quenched by tick anticoagulant protein, just as addition of FXa could not induce phosphorylation of p44/42 MAPK in BHK(+TF) cells. These results suggest a specific mechanism by which binding of FVIIa to cell surface TF independent of coagulation can modulate cellular functions and possibly play a role in angiogenesis and tumor metastasis as indicated by several recent observations.

Animals↗
PubMed1998

A chemical and genetic approach together define the biological consequences of 3-methyladenine lesions in the mammalian genome.

DNA-damaging agents produce a plethora of cellular responses that include p53 induction, cell cycle arrest, and apoptosis. It is generally assumed that it is the DNA damage produced by these agents that triggers such responses, but there is limited direct evidence to support this assumption. Here, we used DNA alkylation repair proficient and deficient isogenic mouse cell lines to demonstrate that the signal to trigger p53 induction, cell cycle arrest, and apoptosis in response to alkylating agents does emanate from DNA damage. Moreover, we established that 3-methyladenine, a relatively minor DNA lesion produced by most methylating agents (which form mainly 7-methylguanine), can specifically induce sister chromatid exchange, chromatid and chromosome gaps and breaks, S phase arrest, the accumulation of p53, and apoptosis. This study was made possible by the generation of 3-methyladenine DNA glycosylase null mutant cells by targeted homologous recombination and by the chemical synthesis of a methylating agent that almost exclusively produces 3-methyladenine DNA lesions. The combined use of these two experimental tools has defined the biological consequences of 3-methyladenine, a DNA lesion produced by endogenous cellular metabolites, environmental carcinogens, and chemotherapeutic alkylating agents.

Adenine↗
PubMed1998

Quantitative and qualitative analysis of DNA methylation at N3-adenine by N-methyl-N-nitrosourea.

The sequence-specific alkylation of DNA by N-methyl-N-nitrosourea (MNU) has been demonstrated for the minor groove N3-methyladenine (N3-MeAde) adduct using neutral thermal hydrolysis and polyacrylamide sequencing gels. The ratio of relative yields of N7- and N3-MeAde and N7-methylguanine (N7-MeGua) is approximately 0.03:0. 15:1.00, respectively, on the basis of the gel data, and these values are comparable to relative yields determined by bulk digestion of MNU-methylated DNA when HPLC was used to analyze the individual adducts. In contrast to the methylation at N7-guanine (N7-Gua) by MNU, alkylation at Ade shows minimal sequence selectivity. Similar to the methylation at N7-Gua, formation of N3-MeAde by MNU is inhibited by 50-200 mM concentrations of NaCl and DNA binding cations, including distamycin and spermine. However, N3-MeAde formation at Ade residues within methidiumpropyl-EDTA-Fe(II) footprinted distamycin DNA affinity binding regions is selectively inhibited at low concentrations of distamycin relative to Ade sites outside of ligand binding regions, and N7-Gua within or outside the distamycin binding regions. HPLC analysis shows that distamycin also quantitatively inhibits the production of N3-methylguanine when calf thymus DNA is treated with MNU or methyl methanesulfonate. The specific inhibitory effect of distamycin, which binds in the minor groove at Ade/Thy-rich sequences, provides additional evidence that the predominant DNA lesion detected at Ade by sequencing gel analysis involves minor groove N3-MeAde modifications.

Adenine↗