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Biomedical subjects

G Butcher

Publications and source records attributed to G Butcher.

14 recordsLinked to original sources
PubMed1992

Buspirone induced prolactin responses in obsessive-compulsive disorder (OCD): is OCD a 5-HT2 receptor disorder?

Buspirone (BUSP) is a serotonergic (5-HT) agonist with activity at the 5-HT1A receptor. The BUSP induced prolactin (PRL) response was examined in 10 patients with a DSM IIIR diagnosis of obsessive-compulsive disorder (OCD). The results were compared with PRL responses to BUSP found in 10 age and sex matched healthy controls. The results suggest that the 5-HT1A receptor dysfunction may not be involved in the pathophysiology of OCD. The authors review the literature and consider the hypothesis that in OCD a complex interaction of other 5-HT receptor sub-types may be occurring, possibly with dysfunction primarily of the 5-HT2 receptors.

Adult↗
PubMed1992

Light and electron microscopic studies of cellular localization of oPL with monoclonal and polyclonal antibodies.

Accurate knowledge of placental lactogen localization is fundamental to any hypothesis of its synthesis and secretion. We used locally generated monoclonal and polyclonal antibodies from three separate sources to localize ovine placental lactogen immunoreactivity on light and electron microscope Lowicryl K4M sections of ovine placentomes of 97-145 days of gestation, using immunogold techniques. All antibodies demonstrated that immunoreactivity was exclusively localized in the trophoectoderm binucleate cell Golgi body and granules and in granules in the syncytium derived from binucleate cell migration. No evidence was found to support a recent claim that monoclonal antibodies to oPL that were produced in Canada indicated a predominant localization of ovine placental lactogen to uninucleate trophectodermal cells.

Animals↗
PubMed1992

Cortisol and prolactin responses to d-fenfluramine in non-depressed patients with obsessive-compulsive disorder: a comparison with depressed and healthy controls.

Cortisol and prolactin responses to d-fenfluramine were measured in 10 drug-free normothymic patients with obsessive-compulsive disorder (OCD). The results were compared with these responses in 10 healthy controls and in 10 major depressives. The endocrine responses in OCD were significantly attenuated when compared to the healthy controls; however, the results were not specific to OCD as the depressives' responses were similarly blunted.

Adult↗
PubMed1991

Probing of the expression of the low-density lipoprotein receptor in vivo using an anti-receptor monoclonal antibody.

MAC188 is a rat anti-[low-density lipoprotein (LDL) receptor] monoclonal antibody (McAb) which binds to the cell surface receptor with high affinity at physiological temperatures, even in the presence of high concentrations of the natural ligand, LDL. Binding of McAb MAC188 at 37 degrees C is followed by internalization and intracellular sequestering of the receptor, which results in the transient disappearance of the receptor from the cell surface. The high binding affinity and epitope specificity of McAb MAC188 suggested that this antibody could be used to quantify receptor expression in vivo. Mixtures of radiolabelled anti-receptor antibody and a control McAb (MAC221) were injected intravenously into rabbits, and the clearance from serum and uptake into tissues was determined. A fraction of the anti-receptor McAb was cleared rapidly from the circulation by a high-affinity and saturable (receptor-dependent) process. Receptor-dependent uptake of the anti-receptor McAb was measurable in liver, adrenal glands, kidneys, spleen, kidney, thoracic aorta and heart. It was highest in liver and adrenal glands and correlated well with the level of receptor protein and the rate of LDL transport in individual tissues. Anti-receptor McAbs such as MAC188, with suitable domain specificity and binding affinity at physiological temperatures, have important advantages over the natural ligand as tracers for the receptor in vivo, and may find widespread applications in studies of the receptor status (activity) in animals and man.

Animals↗
PubMed1990

Identification and localization of high molecular weight proteins in insect flight and leg muscle.

Thick and thin filaments in asynchronous flight muscle overlap nearly completely and thick filaments are attached to the Z-disc by connecting filaments. We have raised antibodies against a fraction of Lethocerus flight muscle myofibrils containing Z-discs and associated filaments and also against a low ionic strength extract of myofibrils. Monoclonal antibodies were obtained to proteins of 800 kd (p800), 700 kd (p700), 400 kd (p400) and alpha-actinin. The positions of the proteins in Lethocerus flight and leg myofibrils were determined by immunofluorescence and electron microscopy. p800 is in connecting filaments of flight myofibrils and in A-bands of leg myofibrils. p700 is in Z-discs of flight myofibrils and an immunologically related protein, p500, is in leg muscle Z-discs. p400 is in M-lines of both flight and leg myofibrils. Preliminary DNA sequencing shows that p800 is related to vertebrate titin and nematode twitchin. Molecules of p800 could extend from the Z-disc a short way along thick filaments, forming a mechanical link between the two structures. All three high molecular weight proteins probably stabilize the structure of the myofibril.

Amino Acid Sequence↗
PubMed1988

Troponin of asynchronous flight muscle.

Troponin has been prepared from the asynchronous flight muscle of Lethocerus (water bug) taking special care to prevent proteolysis. The regulatory complex contained tropomyosin and troponin components. The troponin components were Tn-C (18,000 Mr), Tn-T (apparent Mr 53,000) and a heavy component, Tn-H (apparent Mr 80,000). The troponin was tightly bound to tropomyosin and could not be dissociated from it in non-denaturing conditions. A complex of Tn-T, Tn-H and tropomyosin inhibited actomyosin ATPase activity and the inhibition was relieved by Tn-C from vertebrate striated muscle in the presence of Ca2+. However, unlike vertebrate Tn-I, Tn-H by itself was not inhibitory. Monoclonal antibodies were obtained to Tn-T and Tn-H. Antibody to Tn-T was used to screen an expression library of Drosophila cDNA cloned in lambda phage. The sequence of cDNA coding for the protein was determined and hence the amino acid sequence. The Drosophila protein has a sequence similar to that of vertebrate skeletal and cardiac Tn-T. The sequence extends beyond the carboxyl end of the vertebrate sequences, and the last 40 residues are acidic. Part of the sequence of Drosophila Tn-T is homologous to the carboxyl end of the Drosophila myosin light chain MLC-2 and one anti-Tn-T antibody cross-reacted with the light chain. Lethocerus Tn-H is related to the large tropomyosins of Drosophila flight muscle, for which the amino acid sequence is known, since antibodies that recognize this component also recognize the large tropomyosins. Tn-H is easily digested by calpain, suggesting that part of the molecule has an extended configuration. Electron micrographs of negatively stained specimens showed that Lethocerus thin filaments have projections at about 39 nm intervals, which are not seen on thin filaments from vertebrate striated muscle and are probably due to the relatively large troponin complex. Decoration of the thin filaments with myosin subfragment-1 in rigor conditions appeared not to be affected by the troponin. The troponin of asynchronous flight muscle lacks the Tn-I component of vertebrate striated muscle. Tn-H occurs only in the flight muscle and may be involved in the activation of this muscle by stretch.

Amino Acid Sequence↗
PubMed1987

Class-II and IL2 receptor positive cells in the pancreas of NOD mice.

The aberrant expression of Class-II molecules on pancreatic B cells in Type 1 (insulin-dependent) diabetes is still a matter of debate. In order to verify if Class-II molecules are expressed on islet cells in the NOD mouse we have studied 21 female mice of different ages (5 to 22 weeks). Serial cryostat pancreas sections were stained with monoclonal rat antibodies against Class-II antigens (P7/7) and the IL2 receptor (AMT-13). Our results show no Class-II expression by endocrine cells at any age, whereas about 25-32% of mononuclear cells infiltrating the islets were Class-II positive, and only 6-9% were IL2 receptor positive. No staining, except of occasional tissue macrophages, was observed in the pancreas of BALB/c, CBA or B10.SCSN mice. Our data are in contrast with those recently published and therefore the reality of expression of Class-II molecules by islet cells of NOD mice should be viewed with caution.

Animals↗
PubMed1985

Graft rejection in a congenic panel of rats with defined immune response genes for MHC class I antigens. I. Rejection of and priming to the RT1Aa antigen.

Allograft rejection in the rat has been shown to be under stringent immune response (Ir) gene control using major histocompatibility complex recombinant animals as donors. Presentation of an isolated class I antigenic difference to high responder recipients results in rapid graft rejection, but low responders fail to reject. This striking qualitative difference is also seen in some liver grafting experiments in which the donor presents a full MHC haplotype and minor antigen mismatch to the responders. Grafts of other organs, however, do not discriminate qualitatively between high and low responders when a full haplotype mismatch exists. We have used the canonical high and low-responder animals, (PVG X PVG-RT1u)F1 and PVG to examine whether any qualitative difference in responsiveness can be detected against the a haplotype using a variety of organ grafts. We have confirmed a qualitative difference between high and low responders using PVG.R1 donors presenting an isolated class I (Aa) difference. Rapid rejection by high responders contrasted with complete failure to reject by the low responders. No difference in rejection tempo was found when a full a haplotype mismatch was introduced. This could have reflected vigorous responses to I and C region differences, because rapid rejection through these regions was demonstrated using the PVG.r1 (AaIcCc) and PVG.r8 (AaIuCu) recombinants. The feeble immunogenicity of the Aa antigen for PVG animals was revealed by priming and cross-priming experiments showing not only that r1 failed to prime for subsequent r1 graft rejection, but that the Aa antigen presented in concert with Ia and Ca also failed to prime. An unexpected result was that the Aa antigen of r1 actually suppressed responsiveness, especially when delivered by a heart graft. This suppression not only extended to subsequent r1 grafts (for example, skin rafts) but also to subsequent grafts of a tissue. The mechanism of this suppression remains unclear but preliminary experiments argue in favor of enhancement rather than active suppression.

Animals↗
PubMed1985

Graft rejection in a congenic panel of rats with defined immune response genes for class I antigens. II. Quantitative aspects of Ir gene function in a full-haplotype mismatch.

Previous studies have shown that the Ir-gene-controlled rejection of rl tissues by c/u responder and non-rejection by c low responders does not extend to tissues expressing a full a haplotype mismatch. However, antibody responses and liver graft rejection are both defective in low responders, even across a full haplotype barrier. We have therefore used a titrated adoptive transfer assay to search for quantitative differences in the responsiveness of c and c/u animals to a organ grafts. We first established that a heart graft rejection could be ablated in both recipient strains with whole-body irradiation and could be restored with syngeneic cells. Titration of restorative cells revealed that 5 times as many c cells were required to restore graft rejection in c recipients as c/u cells were required in c/u recipients. Use of cells from primed donors showed that in both c/u and c animals these cells had undergone about a 5-fold increase in potency, showing that there was no failure of proliferation and differentiation in the low responder after contact with antigens. Cross-transfer experiments were done to attempt to localize the defect in low-responder animals either to a failure of low-responder antigen-presenting cells (APC) to trigger a response or a defect in the responsiveness of alloreactive cells toward the a antigens. In these experiments c cells were obtained from radiation chimeras of the c----c/u type. These cells were used to restore graft rejection in c/u irradiated recipients. Similar experiments employing c/u cells obtained from c/u----c chimeras and given to irradiated c recipients were also done. These showed that c cells from chimeras were marginally less potent than c/u cells from chimeras. In contrast when cross-transfer of c/u cells to c animals bearing a nonrejected rl heart was done, no rejection was seen even when antigen presenting cells were cotransferred. The conclusions from this series of experiments were that quantitatively small defects were present in both repertoire and antigen presentation, and that these quantitative defects in aggregate were probably sufficient to explain the documented low responsiveness of c animals to the a haplotype. The failure of high-responder c/u cells to secure rejection of rl tissues in the low-responder c environment suggests that presentation of isolated class I differences in host APCs is mandatory for rejection to occur and is highly defective in the c animal.

Animals↗
PubMedDate not supplied

An outbreak of erysipelas in chukars.

A peracute severe outbreak of erysipelas in chukars (Alectoris chukar) caused 55% mortality. Pheasants and quails on the same premises were not affected. Possible sources of infection and pathogenesis are discussed.

Animals↗