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Biomedical subjects

B Clarke

Publications and source records attributed to B Clarke.

At least 55 records · Page 3Linked to original sources
PubMed2000

Autologous graft-versus-host disease induction in advanced breast cancer: role of peripheral blood progenitor cells.

The purpose of the present study was to investigate the impact of the use of peripheral blood progenitor cells (PBPCs) on the induction of autologous graft-versus-host disease (GVHD) in patients with advanced breast cancer. 14 women with stage IIIB and 36 women with stage IV breast cancer received cyclosporine (CsA) 2.5 mg kg-1 i.v. daily, d 0-28, and interferon-gamma (IFNg) 0.025 mg/m2 s.c. qod, d7-28, following PBPC-T +/- bone marrow transplantation (BMT). Preceding high-dose chemotherapy consisted of cyclophosphamide 6 g/m2 and thiotepa 800 mg/m2. Histologically proven > or = grade II cutaneous GVHD was induced in18/50 (36%) of patients and was independent of the source of haematopoietic support. In vitro studies showed that post-transplant, 76% of patients had developed auto-cytotoxicity against their own pre-transplant PHA-lymphoblasts. A significant correlation between the occurrence of GVHD > or = grade II and cytolysis was observed in the NK cell-line K562 and the T47D breast cancer cell-line. With a median follow-up of 2(1/2) years, the overall survival (OS) is 58%, the disease-free survival (DFS) 26%, both independent of the development of GVHD and similar to what has been observed in other studies on high-dose chemotherapy in advanced breast cancer. It therefore remains unclear whether the induction of autologous GVHD with the occurrence of auto-cytotoxic lymphocytes can result in an anti-tumour effect in this group of patients.

Adult↗
PubMed2000

The structure and expression of the wheat starch synthase III gene. Motifs in the expressed gene define the lineage of the starch synthase III gene family.

The endosperm of hexaploid wheat (Triticum aestivum [L.]) was shown to contain a high molecular weight starch synthase (SS) analogous to the product of the maize du1 gene, starch synthase III (SSIII; DU1). cDNA and genomic DNA sequences encoding wheat SSIII were isolated and characterized. The wheat SSIII cDNA is 5,346 bp long and contains an open reading frame that encodes a 1,628-amino acid polypeptide. A putative N-terminal transit peptide, a 436-amino acid C-terminal catalytic domain, and a central 470-amino acid SSIII-specific domain containing three regions of repeated amino acid similarity were identified in the wheat gene. A fourth region between the transit peptide and the SSIII-specific domain contains repeat motifs that are variable with respect to motif sequence and repeat number between wheat and maize. In dicots, this N-terminal region does not contain repeat motifs and is truncated. The gene encoding wheat SSIII, designated ss3, consists of 16 exons extending over 10 kb, and is located on wheat chromosome I. Expression of ss3 mRNA in wheat was detected in leaves, pre-anthesis florets, and from very early to middle stage of endosperm development. The entire N-terminal variable repeat region and the majority of the SSIII-specific domain are encoded on a single 2,703-bp exon. A gene encoding a class III SS from the Arabidopsis genome sequencing project shows a strongly conserved exon structure to the wheat ss3 gene, with the exception of the N-terminal region. The evolutionary relationships of the genes encoding monocot and dicot class III SSs are discussed.

Amino Acid Sequence↗
PubMed1999

Activation and adoptive transfer of Epstein-Barr virus-specific cytotoxic T cells in solid organ transplant patients with posttransplant lymphoproliferative disease.

The treatment of Epstein-Barr virus (EBV)-associated lymphoproliferative disease (PTLD) in EBV seronegative solid organ transplant recipients who acquire their EBV infection after engraftment poses a considerable challenge because of underlying immunosuppression that inhibits the virus-specific cytotoxic T cell (CTL) response in vivo. We have developed a protocol for activating autologous EBV-specific CTL lines from these patients and show their potential use for immunotherapy against PTLD in solid organ transplant patients. Peripheral blood mononuclear cells from a panel of solid organ transplant recipients with and without active PTLD were used to assess EBV-specific memory CTL responses. The activation protocol involved cocultivation of peripheral blood mononuclear cells with an autologous lymphoblastoid cell line under conditions that favored expansion of virus-specific CTL and hindered the proliferation of allospecific T cells. These CTL consistently showed (i) strong EBV-specificity, including reactivity through defined epitopes in spite of concurrent immunosuppressive therapy, and (ii) no alloreactivity toward donor alloantigens. More importantly, adoptive transfer of these autologous CTLs into a single patient with active PTLD was coincident with a very significant regression of the PTLD. These results demonstrate that a potent EBV-specific memory response can be expanded from solid organ recipients who have acquired their primary EBV infection under high levels of immunosuppressive therapy and that these T cells may have therapeutic potential against PTLD.

Adoptive Transfer↗
PubMed1999

An infectious molecular clone of a Japanese genotype 1b hepatitis C virus.

We describe an infectious molecular clone of a Japanese genotype 1b strain of hepatitis C virus (HCV-N). The molecularly cloned sequence of HCV-N was compared with alignments of other HCV sequences, leading to the identification of 15 unique, nonconservative amino acid substitutions within the HCV-N open reading frame (ORF). These were repaired to the consensus genotype 1b residue, and the infectivity of RNA transcribed from the repaired clone was assessed by intrahepatic inoculation of a chimpanzee. Viral RNA was first detected in the serum of this chimpanzee 3 weeks following inoculation, and was intermittently present over the next 14 weeks. A strong and persistent anti-HCV serological response developed 13 weeks following inoculation, with seroconversion in the recombinant immunoblot assay (RIBA). A weaker, transient serological response, characterized by seroconversion in a third-generation enzyme-linked immunosorbent assay (ELISA) but not RIBA, occurred between weeks 1 and 5. This may have represented an anamnestic response to HCV antigens translated directly from the intrahepatically inoculated RNA, because the animal previously had undergone 2 unsuccessful attempts at rescue of HCV by intrahepatic RNA inoculation. There was neither biochemical nor histological evidence of liver disease. Although this is within the range of expected outcomes in an HCV-naive chimpanzee, prior immunologic priming may have modified the infection in this animal. The HCV-N clone is the first infectious molecular clone of HCV that is comprised entirely of genotype 1b sequence, and it contains an ORF sequence that is significantly divergent from that of a previously described genotype 1a/1b chimera.

3' Untranslated Regions↗
PubMed1999

Translabial color Doppler for imaging in urogynecology: a preliminary report.

OBJECTIVE: A prospective study was conducted to evaluate the use of color Doppler ultrasound in the investigation of female urinary incontinence. METHODS: Thirty-seven patients underwent a full urodynamic assessment and translabial ultrasound examination using color Doppler-capable equipment with 5-7-MHz curved array transducers, both in the supine and in the erect positions. RESULTS: More than minimal leakage was seen in 13 patients by Doppler and in 16 by fluoroscopic imaging. Results were in agreement in 28/37 cases (kappa 0.49). The observed discrepancies may have been due to initial technical difficulties, differences in bladder filling and the presence of a catheter on fluoroscopic imaging. In five incontinent patients, urethral flow velocities ranged from 0.064 to 0.34 m/s, which is equivalent to physiological venous and slow arterial blood flow and one to two orders of magnitude above the detection threshold of standard Doppler ultrasound equipment. CONCLUSIONS: Translabial color Doppler imaging of the lower urinary tract allows the documentation of fluid leakage from the bladder. It has the potential to become the new imaging standard for urogynecology.

Adult↗
PubMed1999

The localization and expression of the class II starch synthases of wheat.

The starch granules of hexaploid wheat (Triticum aestivum) contain a group of three proteins known as SGP-1 (starch granule protein-1) proteins, which have apparent molecular masses of 100, 108, and 115 kD. The nature and role of these proteins has not been defined previously. We demonstrate that these polypeptides are starch synthases that are present in both the starch granule and the soluble fraction at the early stages of wheat endosperm development, but that are exclusively granule bound at mid and late endosperm development. A partial cDNA clone encoding a fragment of the 100-kD protein was obtained by screening a wheat endosperm cDNA expression library using monoclonal antibodies. Three classes of cDNA were subsequently isolated from a wheat endosperm cDNA library by nucleic acid hybridization and were shown to encode the 100-, 108-, and 115-kD proteins. The cDNA sequences are highly homologous to class II starch synthases and have the highest homology with the maize SSIIa (starch synthase IIa) gene. mRNA for the SGP-1 proteins was detected in the leaf, pre-anthesis florets, and endosperm of wheat and is highly expressed in the leaf and in the grain during the early to mid stages of development. We discuss the roles of the SGP-1 proteins in starch biosynthesis in wheat.

Amino Acid Sequence↗
PubMed1999

Patients with morbid obesity don't get life-saving bone marrow transplants.

When the patient, a registered nurse, was surgically treated for morbid obesity she initially lost 54.5 kg. Approximately 2 years after gastric bypass, she received a diagnosis of chronic myelogenous leukemia and subsequently underwent a successful allogenic bone marrow transplant (BMT). When her surgical history was taken at the transplant facility, the significant weight loss and gastric bypass were discussed. She was informed that at 140 kg, she would not have been eligible nor considered a candidate for transplant. A search of the literature and a survey of other facilities confirmed this view as typical. The reasons cited were that the chemotherapy dosage required for the morbidly obese weight level would cause fatal organ damage as opposed to organ-sparing dosages, which would not eradicate all leukemic cancer cells. An additional general view was that the morbidly obese could not survive the rigors of the transplant preoperative regimen. This patient had an uneventful recovery and remains disease-free today, 3 years after BMT and 5 years after gastric bypass, with a sustained total weight loss of 73 kg.

Body Weight↗
PubMed1999

Clinical efficacy and safety of tolterodine compared to placebo in detrusor overactivity.

PURPOSE: We evaluated the efficacy, patient acceptability and side effect profile of tolterodine, a new antimuscarinic agent for treating bladder overactivity. MATERIALS AND METHODS: In our randomized, placebo controlled, parallel group study 123, 129 and 64 patients 18 years old or older with proved detrusor overactivity (idiopathic detrusor instability or detrusor hyperreflexia) were randomized to receive 1 or 2 mg. tolterodine, or placebo, respectively, twice daily for 12 weeks. Main outcome measures were number of voids per 24 hours, urine volume per void and episodes of urge incontinence per 24 hours on a frequency-volume chart with detailed recording of side effects. RESULTS: After 12 weeks of treatment mean number of voids per 24 hours plus or minus standard deviation decreased from 11.2 +/- 3.1 to 9.0 +/- 2.6 with the 2 mg. dosage (p = 0.0045 versus placebo). At this dose mean urine volume per void increased from 155 +/- 52 to 190 +/- 70 ml. (p <0.0001 versus placebo), while mean number of incontinence episodes per 24 hours decreased from 3.6 +/- 4.0 to 1.8 +/- 3.1 (p = 0.19 versus placebo). Similar efficacy was observed in patients receiving the 1 mg. dose. Severe dry mouth was reported by only 2, 1 and 2% of patients given the 1 and 2 mg. dose, and placebo, respectively. There was no clinical or electrocardiographic evidence of significant cardiac adverse events. CONCLUSIONS: Tolterodine administration resulted in a significant decrease in the frequency of voiding and improved voided volume but it was seldom associated with troublesome or severe side effects.

Adult↗
PubMed1998

Histological parameters as predictors of prognosis in childhood brain tumors.

Using histological parameters with high recognition reliability, we retrospectively analyzed all newly diagnosed patients under the age of 16 years (n = 100) with brain and spinal cord tumors presenting to the National Neuroscience Centres of the Richmond and Beaumont Hospitals, Dublin, Ireland, between 1985 and 1990, allowing analysis of 5-year survival in all cases. Tumor histology was reviewed by two neuropathologists blinded to previous histological diagnosis and to the site of lesion. We found that certain histological features such as very low cell density and microcyst formation had a positive effect on prognosis. Mitoses and pleomorphism had a negative effect on prognosis, whereas necrosis and meningeal involvement had no effect on prognosis. It is suggested that identification of reliably recognized histological features rather than assignation of tumors to particular diagnostic categories may be a more reliable predictor of tumor behavior in the pediatric age-group.

Adolescent↗
PubMed1998

Anti-glomerular basement membrane (GBM)-antibody-mediated disease with normal renal function.

BACKGROUND: This study compared the clinical and laboratory characteristics of patients with anti-glomerular basement membrane (GBM) disease and normal renal function, with those of patients with anti-GBM disease where there was renal impairment. METHODS: The medical records of the 14 patients who had presented with anti-GBM disease to our hospital in the past 20 years were reviewed. RESULTS: Five (36%) had a normal serum creatinine or creatinine clearance at presentation. Other features were haemoptysis (2/5, 40%), macroscopic haematuria (2/5, 40%) or systemic symptoms (1/5, 20%). All five (100%) had some degree of haematuria, four (80%) had proteinuria of at least 1 g/day, and none was hypertensive. Anaemia, a raised WCC, or elevated ESR (> 35 mm/h) occurred less often than in patients with impaired renal function (P<0.05). Two of the five (40%) with normal renal function had circulating anti-GBM antibodies, which were present at low or moderate levels; but seven of the nine with renal impairment (77%) had circulating antibodies, with high levels in five. Renal biopsies from patients with normal renal function were normal (1/5, 20%), showed mesangial proliferation (4/5, 80%) or had more than 20% glomeruli sclerosed (1/5, 20%). Complement deposition was present in 2/4 biopsies (50%). The kidneys from patients with renal impairment had crescents in more than 50% glomeruli (9/9, 100%), and four had more than 20% glomeruli sclerosed (44%). All four kidneys from patients with renal impairment that were examined had complement deposits (100%). Treatment was identical in both groups; patients with normal renal function were followed for a median of 48 months, and those with renal impairment for 180 months. There were no further episodes of haemoptysis, haematuria, or other symptoms of relapse in either group. All five patients with normal renal function are alive, and the serum creatinine is less than 0.2 mmol/l in all (100%), but haematuria persists in one (20%), and proteinuria >1 g/day in two (40%). Eight of the nine (89%) patients with impaired renal function survive, but all are currently being dialysed or have had a renal transplant. CONCLUSION: Patients with anti-GBM disease with normal renal function are not uncommon, and often have a good prognosis. There is less renal damage, possibly because of lower levels of circulating anti-GBM antibodies and less glomerular complement deposition.

Adolescent↗
PubMed1997

Induction of cytotoxic T-cell response against hepatitis C virus structural antigens using a defective recombinant adenovirus.

A replication-defective recombinant adenovirus (RAd), RAdCMV-CE1, containing core and E1 genes of hepatitis C virus (HCV) was constructed. RAdCMV-CE1 was able to express core and E1 proteins both in mice and human cells. Immunization of BALB/c mice with RAdCMV-CE1 induced a specific cytotoxic T-cell response against the two HCV proteins. This response was characterized using a panel of 60 synthetic 14- or 15-mer overlapping peptides (10 amino-acid overlap) spanning the entire sequence of these proteins. Five main epitopes were found in the core protein, four of which had been previously described either in mice or humans. One single novel epitope was found in E1. Fine mapping of this E1 determinant, showed that octamer GHRMAWDM is the minimal epitope recognized by cytotoxic T lymphocytes (CTL). The cytotoxic T-cell response was H-2d restricted, lasted for at least 100 days, and was mediated by T cells with the classic CD4-CD8+ phenotype. This work demonstrates that replication-defective recombinant adenoviruses can efficiently express HCV proteins and are able to induce an in vivo cytotoxic T-cell response against a diversity of epitopes from HCV antigens. These vectors should be taken into consideration in the design of vaccines and also as a means to stimulate specific T-cell responses in chronic HCV carriers.

Amino Acid Sequence↗