PubMed Health⌕ Search

Biomedical subjects

G Hunt

Publications and source records attributed to G Hunt.

At least 37 records · Page 2Linked to original sources
PubMed1998

Validation of a capillary isoelectric focusing method for the recombinant monoclonal antibody C2B8.

A capillary isoelectric focusing (cIEF) method has been developed for the purpose of determining the identity and charge distribution of mouse/human chimeric antibody to human CD20 antigen (C2B8). The assay was validated in accordance with ICH guidelines in order to demonstrate that it is suitable for its intended purpose and so that it may be performed as a lot release test for bulk and final product. As a result of the validation process the assay was found to be linear over the concentration range of 2-356 micrograms ml-1 with recovery of 125I-labeled C2B8 at the target sample concentration of 125 micrograms ml-1 equal to 99%. The repeatability and intermediate precision relative standard deviations of the four major peaks for migration time, peak area, and peak area percent ranged from 0.9-4.4%. The specificity of the assay was demonstrated by baseline resolution of the C2B8 main peak from product excipients, and other Genentech monoclonal antibodies. The results of this validation demonstrate that the cIEF assay for the determination of identity and charge distribution of C2B8 is accurate, precise, linear, and highly specific. The assay is rapid and suitably rugged.

Animals↗
PubMed1998

Six-month outcome following a relapse of schizophrenia.

OBJECTIVE: To analyse clinical data on patients with schizophrenia on admission to acute care and 6 months later in order to identify factors associated with frequent hospitalisations and poor outcome. METHOD: Information was collected from the medical records of 99 patients with schizophrenia consecutively admitted to acute care in hospital or by community based 24 h Crisis Teams and prospectively studied for 6 months. RESULTS: One-quarter of patients were being admitted to acute care within 3 months of their last hospital discharge and only 34 patients were compliant with their neuroleptic medication 3 months prior to the index admission. Twenty-one patients were managed entirely by the Crisis Teams, 27 patients received inpatient care only and the remainder (n = 51) had both types of acute care. Six months after admission, 42 patients had been discharged and did not require further acute care, 29 patients had been re-admitted at least once and three patients had been transferred to an inpatient rehabilitation unit and, therefore, remained in hospital over the entire period. Of the remaining 25 patients, one committed suicide 2 months after discharge and the other patients were not contactable by Community Mental Health Teams at the 2 and/or 6 month follow up. CONCLUSIONS: Some of the factors associated with relapse identified in the present study were non-compliance with medication, stress, inadequate social support and substance abuse. The poor outcome in patients with frequent relapses emphasises the need to reduce the occurrences of schizophrenic symptoms to provide a better quality of life. The 25% of patients dropping out of care soon after a relapse indicates that more should be done to engage these people in long-term treatment programs.

Adolescent↗
PubMed1997

Agouti protein inhibits the production of eumelanin and phaeomelanin in the presence and absence of alpha-melanocyte stimulating hormone.

Melanocytes synthesise two types of melanin: the brown-black eumelanin and the red-yellow phaeomelanin. In mice, the relative proportions of these two melanins are regulated by alpha-MSH, which preferentially increases the synthesis of eumelanin and by the Agouti protein (AP), the expression of which correlates with the growth of yellow phaeomelanin-containing hair. It has been proposed that AP acts by antagonizing the action of alpha-MSH at the MC1 receptor, although it has been suggested that it may also act independently of alpha-MSH. In the present study we show that AP inhibits melanogenesis in B16F1 melanoma cells in the presence and absence of alpha-MSH and also causes dose-related decreases in the synthesis of both eumelanin and phaeomelanin. In the presence of alpha-MSH AP had a greater effect on eumelanin production and this is consistent with an antagonistic action at the MC1 receptor. In the absence of alpha-MSH however, AP produced similar reductions in the synthesis of both melanins. These changes were not seen in B16G4F cells which lack the MC1 receptor, suggesting that even in the absence of alpha-MSH AP acts at the MC1 receptor. How this action is mediated at the intracellular level is not yet clear, although it appears to be associated with a decrease in tyrosinase activity.

Adenylyl Cyclases↗
PubMed1997

Moral crisis, professionals and ethical education.

Western civilization has probably reached an impasse, expressed as a crisis on all fronts: economic, technological, environmental and political. This is experienced on the cultural level as a moral crisis or an ethical deficit. Somehow, the means we have always assumed as being adequate to the task of achieving human welfare, health and peace, are failing us. Have we lost sight of the primacy of human ends? Governments still push for economic growth and technological advances, but many are now asking: economic growth for what, technology for what? Health care and nursing are caught up in the same inversion of human priorities. Professionals, such as nurses and midwives, need to take on social responsibilities and a collective civic voice, and play their part in a moral regeneration of society. This involves carrying civic rights and duties into the workplace.

Disclosure↗
PubMed1997

The human condition of the professional: discretion and accountability.

This article takes issue with procedural reductionism, which is the inclination to reduce all matters of judgement and responsibility to the following of some procedure or rule. Two scenarios provide content for a discussion of professional discretion in the context of accountability. The author shows that in professional life there will always be situations that stand beyond the rules of procedures and require the unique judgement of the professional at the time. While this judgement may be determined by the facts available in a situation of uncertainty, it cannot be reduced to the facts (including facts about rules and procedures). The moral judgement will still have an essential indeterminancy about it.

Ethics, Nursing↗
PubMed1996

Comparison of ampholytes used for slab gel and capillary isoelectric focusing of recombinant tissue-type plasminogen activator glycoforms.

Four commercial ampholytes: Ampholine and Pharmalyte (Pharmacia Biotech), Bio-Lyte (Bio-Rad) and Servalyt (Serva) were evaluated for their ability to resolve recombinant tissue-type plasminogen activator (rt-PA) glycoforms by isoelectric focusing (IEF) and capillary IEF (cIEF). Each brand of ampholytes focused rt-PA into 3-4 major and 5-6 minor bands on slab gel electrophoresis. Visually, focused bands stained with Coomassie Blue appeared to be similarly resolved by all the ampholytes except for Ampholines, where the bands were closely grouped and more intensely stained. When cIEF was performed, Pharmalytes and Ampholines resolved rt-PA glycoforms consistent with the slab gels. No discernible peaks were detected during cIEF of rt-PA using Servalyts or Bio-Lytes. UV spectrophotometric scans of the components used for cIEF showed that Servalyts absorbed intensely over a range which overlapped the detector bandpass. Bio-Lytes showed absorption over a narrower UV range but still overlapped the detector bandpass, thus preventing the discernment of protein peaks. For this cIEF system the best ampholytes were Ampholines and Pharmalytes.

Amino Acids↗
PubMed1996

Capillary isoelectric focusing and sodium dodecyl sulfate-capillary gel electrophoresis of recombinant humanized monoclonal antibody HER2.

Capillary isoelectric focusing (cIEF) and IEF of recombinant humanized monoclonal antibody HER2 (rhuMAbHER2) show five charged isoforms with estimated pI values ranging from 8.6-9.1. The cIEF assay demonstrated good precision with relative standard deviations (R.S.D.) 0.7-3.7% and 0.4-4.2% for intra and interassay analysis, respectively. The method was linear for the area of the main peak over the concentration range 2-250 micrograms/ml with a Pearson correlation coefficient > 0.99. The limit of detection for the main peak was determined to be 2 ppm. With both sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE) and SDS-polyacrylamide gel electrophoresis, the nonreduced rhuMAbHER2 migrated as a single major peak with minor peaks in the aggregate and clip regions. After reduction, the electropherogram and the slab gel showed the expected heavy chain and light chain fragments with minor peaks in the aggregate and clip regions. The SDS-CGE assay showed good precision with R.S.D. values of 0.1-7.8% and 0.1-8.1% for intra and interassay analysis, respectively. The Pearson correlation coefficient for the area of the main peak was > 0.99 demonstrating linearity for the concentration range 0.5-500 micrograms/ml. The limit of detection for intact rhuMAbHER2 was determined to be 0.5 ppm. The data presented demonstrates the feasibility of replacing the slab gel techniques with capillary electrophoresis in a quality control environment.

Antibodies, Monoclonal↗
PubMed1996

Unresponsiveness of human epidermal melanocytes to melanocyte-stimulating hormone and its association with red hair.

There is increasing evidence that pro-opiomelanocortin-derived peptides have a role in controlling human skin pigmentation. In vitro, human epidermal melanocytes respond to melanocyte-stimulating hormone (MSH) with increases in melanogenesis and cell dendricity. However, in the present study, not all melanocyte cultures exhibited these changes and 24% were totally unresponsive to MSH. This unresponsiveness was limited to melanocytes from white Europeans but was particularly prevalent in cultures from individuals with red hair. Cyclic AMP, the second messenger of the melanocyte-associated MSH (MC-1) receptor, induced melanocyte dendricity, even in those cultures which were morphologically unresponsive to MSH. The cyclic nucleotide also increased melanogenesis in the cultures that responded melanogenically to MSH but its effect was reduced in those cultures that were unresponsive to MSH. Thus, while the morphological data support the hypothesis that unresponsiveness is mediated at the MSH receptor, intracellular events may also be important in determining melanogenic unresponsiveness to MSH.

Adult↗
PubMed1996

Insulin response in bulimia nervosa as a marker of nutritional depletion.

OBJECTIVE: The aim of this provocation study was to examine insulin, glucose, and cortisol levels in response to a glucose load in bulimia nervosa patients and to relate this to behavior, treatment status, and depressive symptomatology. METHOD: A 3-hr glucose tolerance test was performed in 15 female patients and in 4 controls. Tests were performed at different stages of treatment and following documented engagement in the patient's usual or previous repertoire of bulimic behaviors in the 24 hr prior to testing. Insulin, glucose, and cortisol levels were assayed at baseline and at 30-min intervals following the glucose load. Presence or absence of significant depressive symptomatology was ascertained. RESULTS: Three patterns of insulin response were identified: (1) an exaggerated response, (2) a normative response which resembled that of healthy controls, and (3) a blunted pattern. A reciprocal relationship between peak insulin and mean cortisol levels was seen with higher depression scores associated with blunted insulin response. Patients whose response was exaggerated binged and vomited relatively infrequently and were of stable weight. The insulin response of successfully treated patients, abstinent from binging and vomiting for 4 weeks, was similar to that of normal controls. A blunted response occurred in patients who binged and vomited more frequently, whose weight was unstable, and whose baseline eating was chaotic or nonexistent. DISCUSSION: The exaggerated insulin response was seen as a physiological adaptation to intermittent starvation reversible with treatment, while the blunted insulin response associated with higher cortisol levels was seen to result from more constant nutritional deprivation secondary to greater disturbance of behavior.

Adult↗
PubMed1995

Rapid one-step capillary isoelectric focusing method to monitor charged glycoforms of recombinant human tissue-type plasminogen activator.

A rapid (< 10 min) one-step capillary isoelectric focusing (cIEF) method was developed to monitor charged glycoforms of recombinant human tissue-type plasminogen activator (rt-PA). Focusing takes place between the detector and the anode and the electro-osmotic flow (EOF) sweeps the separated glycoforms past the detector, towards the cathode. The separation uses a neutral coated capillary and hydroxypropylmethylcellulose (HPMC) to reduce the EOF to a constant and reproducible value. The method uses an ampholyte mix with a 50:50 ratio of pH 5-8 and pH 3-10 ampholytes in 4 M urea and 0.1% HPMC to produce maximal resolution whilst maintaining protein solubility during focusing. The electropherograms were compared to isoelectric focusing (IEF) slab gels of samples of intact rt-PA. In both cases approximately ten charged species could be detected. Data analysis indicated that the intra-assay precision was < 5% for peak migration times and < 10% for normalized peak areas. The number of charged species detected by each of the two methods was consistent for samples of intact rt-PA, rt-PA types I and II and for neuraminidase-digested rt-PA. Overall the data indicate that the automated cIEF method can be an adjunct to slab-gel IEF in the characterization and routine analysis of recombinant glycoproteins.

Animals↗
PubMed1995

Respiratory depression in a patient receiving oral methadone for cancer pain.

Methadone is a synthetic opioid with excellent oral bioavailability, variable, but long duration of action and extremely low cost. Our group has found that methadone is well tolerated in patients with difficult pain syndromes who are receiving high dose opioids. However, because of high interpersonal variation in bioavailability and the long duration of action of this drug, treatments should be highly personalized. We report on a 61 year old cancer patient who was switched from 84 mg/day of subcutaneous hydromorphone to 90 mg/day of oral methadone. On this dose, she developed respiratory depression and non-cardiogenic pulmonary edema that responded to subcutaneous naloxone and methadone discontinuation. Our findings suggest that standard equalanalgesic tables are unreliable for methadone titration. Switchovers should take place slowly and in a personalized fashion.

Administration, Oral↗
PubMed1995

Field evaluation of four repellents against Leptoconops americanus (Diptera: Ceratopogonidae) biting midges.

Four repellents, deet, AI3-37220, AI3-35765, and CIC-4, prepared as 12.5% ethanol solutions, were evaluated against biting midges on Stansbury Islands, UT. Leptoconops americanus Carter was the only species that was biting human volunteers during the study. This species bit primarily on the ears at rates up to 840 bites per hour. All four repellents significantly reduced the number of bites on treated volunteers. AI3-37220 consistently provided the longest period of protection, giving 97 and 74% protection at 4 and 8 h, respectively. In a direct statistical comparison, AI3-37220 significantly outperformed deet. CIC-4 and AI3-35765 were the least effective repellents, providing 45-47% protection 8 h after application.

Animals↗
PubMed1995

Nle4DPhe7 alpha-melanocyte-stimulating hormone increases the eumelanin:phaeomelanin ratio in cultured human melanocytes.

In mammals, melanin exists in two chemically distinct forms: the red-yellow phaeomelanin and the brown-black eumelanin. Although administration of the pigmentary hormone alpha-melanocyte-stimulating hormone (alpha MSH) and its synthetic analogue Nle4DPhe7 alpha MSH induces skin darkening in man, the increases in melanogenesis in cultured human melanocytes in response to these peptides are relatively small. However, it is possible that MSH affects the eumelanin:phaeomelanin ratio rather than total cellular melanin. Thus, this study examined the specific effects of Nle4DPhe7 alpha MSH on the two melanins in cultured human melanocytes, quantifying eumelanin and phaeomelanin by high performance liquid chromatography. Nle4DPhe7 alpha MSH induced significant increases in the eumelanin content of these cells while having lesser and varied effects on the levels of phaeomelanin. As a consequence, the eumelanin:phaoemelanin ratio was increased in every culture. These results demonstrate that Nle4DPhe7 alpha MSH affects melanin type in human melanocytes and suggest a possible mechanism by which this peptide induces skin darkening in man.

Adolescent↗