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M Griffiths

Publications and source records attributed to M Griffiths.

At least 109 records · Page 6Linked to original sources
PubMed1993

The role of glutamine and glucose analogues in metabolic inhibition of human myeloid leukaemia in vitro.

1. Glutamine analogues L-[alpha S,5S]-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (acivicin) and 6-diazo-5-oxo-L-norleucine (DON) have been shown to possess cytotoxic activity against a wide variety of animal and human xenografted solid tumours, however their potential in man has been limited by toxicity. 2. We have analysed the effects of acivicin and DON on glutamine utilization to determine whether the reason for the disappointing therapeutic profile is solely due to the inefficient inhibition of glutamine metabolism. 3. Human myeloid leukaemic cells treated with acivicin inhibited ribonucleotide biosynthesis but not energy production via glutaminolysis and had little effect on viability, whereas treatment with DON inhibited both ribonucleotide biosynthesis and glutamine oxidation and resulted in reduced viability. 4. Treatment of the myeloid leukaemic cells with the glucose analogue 2-deoxy-D-glucose in addition to DON potentiated the inhibition of de novo nucleotide biosynthesis, glutaminolysis and glycolysis, and caused a further reduction in cell viability. 5. These results provide further support for the essential role of glutamine in cellular metabolism, and indicate that use of the glutamine analogue DON in the treatment of acute myeloid leukaemia may be more clinically effective if used in combination with 2-deoxy-D-glucose.

Acute Disease↗
PubMed1993

Wide variation in patient response to midazolam sedation for outpatient oral surgery.

Intravenous midazolam in doses of between 0.07 mg/kg and 0.1 mg/kg has been recommended for sedation in dentistry and some medical procedures and investigations. This study examined the variable sensitivity of patients to midazolam. One hundred and thirty-four fit but anxious patients between the ages of 16 and 63 years received midazolam intravenously for sedation for minor oral surgery. Doses required ranged from 0.04 to 0.40 mg/kg. Nineteen patients required doses less than 0.07 mg/kg; 59 patients required doses greater than 0.1 mg/kg. The mean dose per kilogram required for males was significantly less than for females. The wide variation in sensitivity to midazolam is confirmed.

Adolescent↗
PubMed1993

Prevention of collagen induced arthritis in mice by deletion of T cell receptor V beta 8 bearing T cells with monoclonal antibodies.

Collagen induced arthritis (CIA) is an animal model of inflammatory polyarthritis. Immunotherapy with the monoclonal antibody F23.1, which deletes V beta 8 bearing T cells, significantly decreased the incidence of CIA in mice. Treatment with the monoclonal antibody 466B5, to delete V beta 6 bearing T cells in combination with F23.1 was no more effective than F23.1 alone and the CIA incidence in 466B5 treated animals was not significantly different from controls. Thus, the V beta 8 family of T cell receptor is expressed on self-reactive T cells in the CIA model of B10.RIII mice injected with porcine type II collagen.

Animals↗
PubMed1993

Identification of the 9G4 idiotope in systemic lupus erythematosus.

An idiotope designated 9G4 (9G4Id) is known to be a marker for immunoglobulins which utilize a particular VH gene, VH4-21. The idiotope has been found to be present on anti-DNA antibodies, and have been identified in 45% of sera from patients with SLE. This idiotope is strongly associated with lupus being very uncommon amongst the other autoimmune rheumatic diseases tested. This distinction is unlike virtually any of the other DNA antibody idiotypes described which are much more widely distributed. 9G4Id levels were found to fluctuate with disease activity in some lupus patients and this idiotope was detected in 3/11 SLE renal biopsies tested. Its presence is associated with the HLA markers A1 and B8 and raised 9G4Id levels are not simply a reflection of hypergammaglobulinaemia. Thus a new DNA antibody associated idiotope has been identified. Expression of the idiotope indicates that a notable proportion of anti-DNA antibodies have VH segments encoded by the same, or closely related genes, and that these restricted immunoglobulins are involved in the renal pathology found in SLE.

Humans↗
PubMed1993

Blood glutathione status during exercise: effect of carbohydrate supplementation.

Blood glutathione status and activities of antioxidant enzymes have been investigated during prolonged exercise with or without carbohydrate (CHO) supplementation. Eight subjects cycled at approximately 70% of maximal oxygen uptake to fatigue [134 +/- 19 (SE) min] on the first occasion (control, CON) and at the same work load and duration on the second occasion but with CHO ingestion during exercise. Blood reduced glutathione (GSH) concentration increased from 0.55 +/- 0.05 mM at rest to 0.77 +/- 0.09 mM after 120 min of exercise during CON (P < 0.01) but remained constant during CHO exercise. Blood glutathione disulfide (GSSG) levels were unchanged during CON and CHO exercise. Blood GSH + GSSG content and GSH/GSSG ratio were also significantly (P < 0.05) elevated during CON but not during CHO exercise. The increases in GSH and GSH + GSSG in CON were associated with decreases in plasma glucose and insulin levels. Activities of blood GSH peroxidase, GSSG reductase, and glucose-6-phosphate dehydrogenase were significantly increased during the CHO exercise, whereas only GSSG reductase activity was elevated during the CON ride. It is concluded that blood GSH increases during prolonged exercise and that CHO supplementation may prevent blood GSH increase possibly because of its inhibitory effects on hepatic hormonal releases, which stimulate GSH output.

Adult↗
PubMed1992

Perineal tears.

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Episiotomy↗
PubMed1992

Familial mesothelioma. Details of 17 cases with histopathologic findings and mineral analysis.

Nine new cases of mesothelioma clustering in four families are described, and additional information is provided on four previously reported families. All of the members of these families had some exposure to asbestos. Diagnoses were confirmed histologically, and the relevance of the histologic pattern is discussed after the literature review. The lung mineral fiber burden was quantified in patients by transmission electron microscopic examination and energy-dispersive x-ray analysis, and this confirmed significant exposure to amphibole asbestos in all patients. Evidence supporting an increased incidence of mesothelioma in family members is discussed.

Aged↗
PubMed1992

Immunohistochemical and functional studies of glycoprotein 60 (gp60) in platelets.

We showed by immunofluorescence, immunoelectron microscopy and Western blot analysis that the plasma glycoprotein (gp60), an Fc gamma binding protein which inhibits complement-mediated prevention of immune precipitation, is present in platelets. The gp60 content of platelets in normal individuals and patients with rheumatoid arthritis was similar (mean 0.028 and 0.024 fg/platelet respectively). Immunoelectron microscopic studies showed that gp60 was present in the cytoplasm and the surface connecting structures but not in the alpha granules, dense granules or lysosomes. Using this technique gp60 was also found on platelet membranes, an observation which was confirmed by immunofluorescence. Activation of platelets with thrombin, calcium ionophore, and immune complexes (IC) resulted in the release of the contents of the alpha granules (beta-thromboglobulin), dense granules (5-hydroxytryptamine) and lysosomes (beta-glucuronidase) but did not induce gp60 secretion. The inability of Fab anti-gp60 to inhibit IC-mediated platelet aggregation and of F(ab')2 anti-gp60 to produce platelet aggregation suggested that IC-mediated platelet aggregation did not occur as a result of the interaction of IC with platelet gp60. However, as the preincubation of IC with purified gp60 produced dose-dependent inhibition of the ability of IC to aggregate platelets it is possible that fluid-phase plasma gp60 modulates the interaction of IC with platelets.

Blood Platelets↗
PubMed1992

Exocrine pancreatic function in mediastinal teratomata: an aid to preoperative diagnosis?

The diagnosis of teratoma may be made by demonstration of high amylase content in fluid aspirated from anterior mediastinal lesions. In 2 cases of mediastinal teratoma proteolytic enzyme activity was evident at the time of operation. A diagnosis of mediastinal teratoma was aided in 2 subsequent cases by demonstration of elevated amylase activity in the aspirated fluid before definitive operation.

Adolescent↗
PubMed1992

Assessing the outcomes of nursing care.

There are many dimensions to outcome measurement for patient care and this study focuses on one aspect of outcome, namely that which is most concerned with the immediate effects of nursing care. Traditionally, outcome studies have been almost exclusively concerned with measuring the clinical outcomes of care with very little attempt being made to assess the effect of the nurses' contributions to that care. One of this study's purposes has been to redress this imbalance. As part of a research project on skill mix and the effectiveness of nursing care, a number of patient-focused standards related to the outcome of nursing care were designed. These were tested, in a case study situation, on 15 wards at seven acute hospitals. Initial testing indicates that these outcome measures show promise as a valid and reliable evaluation instrument with the utility for easy application in the clinical setting. They are being presented as a possible way forward to assessing the outcomes of nursing care.

Humans↗
PubMed1992

Evidence for B-lymphocyte mitogen activity in Borrelia burgdorferi-infected mice.

Borrelia burgdorferi produces a mitogen for murine B lymphocytes which can be measured in vitro by polyclonal stimulation of proliferation and immunoglobulin production (R. Schoenfeld, B. Araneo, Y. Ma, L. Yang, and J. J. Weis, Infect. Immun. 60:455-464, 1992). Sonicated B. burgdorferi cells also stimulated IL-6 production by splenocyte cultures. We have used the murine model for Lyme disease described by Barthold et al. (S. W. Barthold, D. S. Beck, G. M. Hansen, G. A. Terwilliger, and K. D. Moody, J. Infect. Dis. 162:133-138, 1990) to determine whether the B. burgdorferi B-cell mitogen is expressed during active infection. To correlate arthritic changes with immune events, we have studied two strains of mice injected with B. burgdorferi; one of them, C3H/HeJ, developed severe disease, and the other, BALB/c, developed only mild disease. C3H/HeJ mice displayed a persistent 10-fold increase in circulating immunoglobulin G (IgG) levels, a 2-fold increase in IgM levels, and a 15-fold increase in peripheral lymph node B-cell numbers, providing evidence of mitogenic activity. Infected BALB/c mice also had evidence for mitogen activity, since the IgG level in serum increased three- to fourfold. The bulk of the increase in circulating IgG levels was not directed against B. burgdorferi antigens, supporting the occurrence of polyclonal B-cell activation. Analysis of IgG isotypes pointed out a contrast between C3H/HeJ and BALB/c mice in that levels of all isotypes were elevated somewhat in both strains of infected mice but IgG2a levels were much more dramatically increased in the C3H/HeJ mice (28-fold) than in the BALB/c mice (4-fold). In this study, interleukin-6 levels were found to be persistently elevated in the serum of infected C3H/HeJ mice. Interestingly, interleukin-6 levels in serum were much lower in the infected BALB/c mice. These findings indicate that the B. burgdorferi mitogen is active in infected animals and may contribute to the inflammatory and immune response to infection.

Animals↗
PubMed1992

Prevention of collagen induced arthritis in mice by treatment with an antibody directed against the T cell receptor alpha beta framework.

Collagen induced arthritis (CIA) is an animal model of inflammatory polyarthritis. Type II collagen is the major matrix protein of hyaline cartilage. Susceptibility to CIA is linked to the Major Histocompatibility Complex Class II genes but the presence of T cells expressing specific variable beta (V beta) chain of their T cell receptor (TCR) is also required. Pretreatment with the monoclonal antibody H57-597 directed against the TCR alpha beta framework prevented the onset of arthritis in the majority of animals. The depletion of the T cell population did not lead to any apparent health problems. These experiments demonstrate the important role of the alpha/beta T cell and its receptors in the CIA model. Further, anti-TCR alpha beta antibodies may be of value in the therapy of autoreactive disorders.

Animals↗