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William Smith

Publications and source records attributed to William Smith.

6 recordsLinked to original sources
PubMed2026

Peptide ligands targeting GP64 for the purification of Baculovirus from insect cell lysates.

Autographa californica multiple nucleopolyhedrovirus, known as Baculovirus, is a widely used platform for producing therapeutic proteins and viral vectors. The purity and infectious activity of Baculovirus stocks determine the quality and productivity of recombinant products produced through this system. Current purification strategies suffer from major limitations: centrifugation lacks productivity and scalability; ion-exchange chromatography affords limited selectivity and purity; and the only commercial affinity resin requires harsh elution conditions that significantly reduce functional product recovery. To overcome these limitations, this study introduces the first peptide affinity ligands targeting the baculoviral envelope glycoprotein GP64 for the purification of active Baculovirus particles. We implemented a combinatorial selection workflow based on dual-fluorescence screening of solid-phase peptide libraries to identify 12-mer sequences that bind GP64 and elute Baculovirus under mild conditions (pH 8.5). As the selected ligands are enriched in histidine and tyrosine residues, product release is effected by the combined modulation of pH and ionic strength. Eight candidate peptides (SB1-SB8) were evaluated on Toyopearl and POROS chromatographic resins, demonstrating that matrix chemistry, pore size, and ligand density govern purification performance. The lead peptide SB4 conjugated to POROS resin at ∼10 µmol/mL achieved 81% recovery of infectious virions (transducing units), robust host cell protein reduction (LRV 1.65), and a dynamic binding capacity (DBC10%) of 1.9 × 1010 vg/mL resin. Transmission electron microscopy and multi-angle light scattering confirmed the integrity of purified particles (200 × 50 nm rods with intact nucleocapsids), compared to BacuClear eluates that showed collapsed morphology. The SB4-POROS resin demonstrated storage stability and ∼80% retention of binding capacity over ten purification-regeneration cycles with caustic cleaning. Integration into a three-step downstream process (clarification, affinity capture, and polishing) raised product purity 1,528-fold, from 6.22 × 106 to 9.50 × 109 viral genomes per µg of HCP, while reducing the total HCP burden 1,698-fold, at a cumulative transducing-unit yield of ∼69% relative to the feedstock, establishing SB4-POROS as a promising technology with a favorable projected cost structure for Baculovirus purification.

Affinity chromatography↗
PubMed2002

The effect of vardenafil, a potent and highly selective phosphodiesterase-5 inhibitor for the treatment of erectile dysfunction, on the cardiovascular response to exercise in patients with coronary artery disease.

OBJECTIVES: The effect of vardenafil, a potent and highly selective phosphodiesterase-5 (PDE5) inhibitor, on symptom-limited exercise time, time to first awareness of angina, and time to ischemic threshold (ST-segment depression > or =1 mm from baseline) during exercise tolerance testing (ETT) was examined in patients with stable coronary artery disease (CAD). BACKGROUND: Erectile dysfunction (ED) is common among men with CAD. PDE5 inhibition is increasingly the preferred treatment option for ED. However, the effect of PDE5 inhibition on exercise-induced ischemia in CAD patients has received limited prospective evaluation. METHODS: In this double-blind, crossover, single-dose multicenter study, 41 men with reproducible stable exertional angina due to ischemic CAD received vardenafil 10 mg or placebo, followed by ETT (5 to 10 metabolic equivalents [METS], Bruce protocol) 1 h postdose. Sublingual nitrate use was prohibited for > or =24 h pre- and postexercise study days. End points included symptom-limited treadmill exercise time, time to first awareness of angina, time to ischemic threshold, and safety. RESULTS: Relative to placebo, vardenafil 10 mg did not alter exercise treadmill time (427 +/- 105 s vs. 433 +/- 109 s, p = 0.39), or time to first awareness of angina (292 +/- 110 s vs. 291 +/- 123 s, p = 0.59), but significantly prolonged time to ischemic threshold (334 +/- 108 s vs. 381 +/- 108, p = 0.0004). At peak exercise, vardenafil 10 mg did not alter blood pressure, heart rate, or rate-pressure product relative to placebo. The most common adverse events (facial flushing and headache) were of mild or moderate intensity, and short-lived. CONCLUSIONS: Vardenafil 10 mg did not impair the ability of patients with stable CAD to exercise at levels equivalent or greater than that attained during sexual intercourse (average of 2.5 to 3.3 METS).

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2002

Community-based interventions.

This paper explores the potential of community-based, public health-oriented interventions as a tool for reducing the burden of affective disorders on individuals, their families, and communities. The paper reviews the use of community-based interventions with other health-related problems and describes potential applicability for affective disorders such as changing public attitudes, reducing social stigma, facilitating access, or supporting treatment adherence for populations in their community settings. An agenda for developing this field of intervention research is proposed.

Community Mental Health Services↗
PubMed2002

Safety and tolerability of tegaserod in patients with irritable bowel syndrome and diarrhea symptoms.

OBJECTIVES: Tegaserod is a selective serotonin (5-HT4) receptor partial agonist effective in providing relief from abdominal pain, bloating, and constipation in patients with irritable bowel syndrome. Tegaserod therapy may be associated with early transient diarrhea, which is related to its mechanism of action. This study was performed in patients with irritable bowel syndrome and symptoms of diarrhea to further assess the safety of tegaserod. METHODS: After a 2-wk baseline, patients were randomized (2:2:1) in a double-blind manner to receive 4 mg of tegaserod a day (n = 35), 12 mg of tegaserod a day (n = 34), or placebos (n = 17) for 8 wk. Patients had to fulfill > or =2 Rome diarrhea criteria > or =25% of the time. Adverse events were recorded. RESULTS: Diarrhea, abdominal pain, headache, flatulence, and fatigue were the most frequently reported adverse events. The frequency rates of diarrhea were 49%, 18%, and 35% for the 4 mg/day, 12 mg/day, and placebo groups, respectively; when the tegaserod data were pooled, the frequency of diarrhea was similar to that of the placebo group (33% and 35%, respectively). No complications of diarrhea (e.g., dehydration and electrolyte abnormalities) were reported. Five patients (6%), all from the tegaserod groups, discontinued study participation because of diarrhea and/or abdominal pain. No serious adverse events were reported. CONCLUSIONS: In this study, tegaserod at doses of 4 and 12 mg/day was safe and not associated with complications of diarrhea or serious adverse events.

Adult↗
PubMedDate not supplied

Differences in metabolic parameters and gene expression related to osteochondrosis/osteoarthrosis in pigs fed 25-hydroxyvitamin D3.

Osteochondrosis/osteoarthrosis (OC/OA) are common terms for various joint pathologies that occur in pigs. Pathologies that may contribute to these disorders have been described, but the primary cause(s) remain unknown. We hypothesised that as OC has some similarities to dyschondroplasia, which involves a failure of growth plate chondrocytes to fully differentiate and hypertrophy, treatment with 25-hydroxyvitamin D3 (25-D) might reduce the incidence and/or severity of lesions in pigs, as it does in chickens with dyschondroplasia. Control pigs were fed a commercial diet ad libitum. In the treated group this diet was supplemented with 25-D at 0.1 mg/kg. Ten pigs from each of the control and treated groups were sampled at 7, 12, 16 and 21 weeks. Treatment with 25-D had no effect on the incidence or severity of OC/OA lesions. Cartilage dry weight, total collagen content and proteoglycan content, and plasma levels oftotal calcium, inorganic phosphorous, vitamin C, insuline-like growth factor-I, parathyroid hormone and tumour necrosis factor alpha were unaffected by treatment. In addition, none of these parameters were correlated with the incidence or severity of OC/OA lesions. The mRNA expression levels of 21 out of 23 genes assayed by RT-PCR were unaltered in articular cartilage from OA lesion samples as compared to normal articular cartilage. However, collagen type II was reduced and collagen type X increased in OA lesion and near lesion samples. These results suggest that OA in pigs may share some features of osteoarthritis in other mammalian species.

Animals↗