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Biomedical subjects

M J Phillips

Publications and source records attributed to M J Phillips.

At least 55 records · Page 3Linked to original sources
PubMed1997

Behavioral and neuroendocrine responses to m-chlorophenylpiperazine in subtypes of alcoholics and in healthy comparison subjects.

OBJECTIVE: The purpose of this study was to explore central serotonergic functions in subgroups of alcoholics and in healthy comparison subjects. METHOD: The mixed serotonin (5-HT) agonist/antagonist m-chlorophenylpiperazine (m-CPP) was administered to male alcoholic patients who were classified according to the criteria of von Knorring et al. as type I alcoholics (late onset) (N = 16) or type II alcoholics (early onset with antisocial traits) (N = 24) and to 22 healthy comparison subjects. Psychological, physiological, and neuroendocrine measures were obtained before and after the m-CPP infusion. RESULTS: m-CPP elicited subtype-related differential effects among the alcoholics; the type I alcoholics reported more anger and anxiety, and the type II alcoholics reported increased euphoria and a greater likelihood of drinking. The healthy comparison subjects exhibited a greater increase in plasma ACTH response to the m-CPP infusion than the alcoholics regardless of subtype. CONCLUSIONS: Differences in certain 5-HT receptor functions may explain some of the clinical characteristics that differentiate the type II and type I subgroups of alcoholic patients. Furthermore, alcoholics may have reduced sensitivity of 5-HT2C receptors in comparison with healthy subjects.

Adrenocorticotropic Hormone↗
PubMed1997

Evaluation of liver transplantation for high-risk indications.

BACKGROUND: Appropriate use of orthotopic liver transplantation (OLT) requires continued assessment of the indications for transplantation as a number of diseases are associated with a poor prognosis. High-risk patients are those who have a poor survival or high incidence of recurrent disease (patients with tumours, hepatitis B- or hepatitis C-induced cirrhosis, fulminant hepatic failure or primary graft non-function). In addition, retransplantation may be associated with a poor outcome. METHODS: A retrospective review was made of the records of all adult patients undergoing OLT at this hospital between October 1985 and July 1994. RESULTS: A total of 396 liver transplants were performed in 364 patients. The 1- and 3-year actuarial survival rates were 81 and 69 per cent respectively. The overall survival rate of high-risk patients was significantly lower than that for all OLT recipients (P < 0.05). While no patients transplanted for hepatitis C have developed graft failure, recurrent hepatitis occurred in 15 of 35 patients. CONCLUSION: Strict selection criteria and appropriate perioperative investigations and interventions are required to improve the results of OLT in these high-risk patients.

Adolescent↗
PubMed1997

Intermittent claudication should not be treated by surgery.

This debate examines the proposition that surgery is unnecessary or obsolete in the management of intermittent claudication. The case for this argument is that many patients have stable disease or respond well to conservative measures, that claudication is an expression of a systemic cardiovascular illness and that surgery can be replaced by endovascular techniques with equal success, and less disadvantage in the event of treatment failure. The case against the motion is that claudication is associated with repeated cycles of ischaemia and reperfusion, and that these contribute to excess cardiovascular mortality states and, furthermore, that surgery is the only option to relieve symptoms for many patients, especially those with distal disease.

Angioplasty, Balloon↗
PubMed1997

[Immunologic significance of lymphatic drainage of the brain].

Despite the evidence for immunological reactions in the human CNS, in viral encephalitis and in multiple sclerosis, connections between the brain and the immune system are poorly understood. In rodents, tracers injected into the interstitial fluid of the brain drain to the cervical lymph nodes by perivascular pathways in the brain and nasal lymphatics. Similar pathways could serve as lymphatics in the human brain. In the present study, we test the hypothesis that lymphatic drainage of the brain and cervical lymph nodes play a key role in T-cell mediated immunity of the brain. Experimental allergic encephalomyelitis (EAE) was induced in Lewis rats by the injection of guinea pig spinal cord homogenate in complete Freund's adjuvant into the foot pads. This resulted in paralysis of the hind limbs and infiltration of lymphocytes and microglial activation centred mainly on the spinal cord; little inflammation was seen in the cerebrum. When a brain wound, in the form of cryolesion, was inflicted on one cerebral hemisphere, 8 days after the induction of EAE, there was a 6-fold enhancement of EAE lesions in the brain. This enhancement was reduced by 40% cervical lymphadenectomy at the time of the cryolesion. These results suggest that cervical lymph nodes play a pivotal role in cerebral EAE and may be a major source of brain-directed lymphocytes. If similar mechanisms apply in man, study of cervical lymphocytes and their manipulation could open new therapeutic avenues for the treatment of multiple sclerosis.

Animals↗
PubMed1996

Excess zinc associated with severe progressive cholestasis in Cree and Ojibwa-Cree children.

BACKGROUND: High hepatic copper concentrations have been reported in several liver disorders. We report six Native Canadian children with severe chronic cholestatic liver disease, who had excess hepatic copper and zinc. METHODS: The children, aged 22 months to 8 years, came from northern Ontario, Canada. All were referred for possible liver transplantation because of end-stage liver disease. We examined explanted liver samples (or liver biopsy material in one case) by scanning transmission electronmicroscopic (STEM) X-ray elemental microanalysis and atomic absorption spectrophotometry. Samples from four controls (two with no liver pathology, one with biliary atresia, and one with Wilson's disease) were also analysed by atomic absorption spectrophotometry. FINDINGS: The explanted livers showed similar distinctive signs of advanced biliary cirrhosis, and on electronmicroscopy there were dense deposits in enlarged lysosomes and in cytoplasm. Hepatic copper concentrations were many times higher in the five patients with measurements (47.6-56.9 microgram/g dry weight) than in two samples of normal control liver tissue (2.3 and 2.9 microgram/g). Similarly, hepatic zinc concentrations were many times higher in the patients than in controls (104-128 vs 1.9-3.2 microgram/g dry weight). INTERPRETATION: The excess copper may be due to chronic cholestasis but the excess zinc is unexplained. Since three of the patients are related (shared grandparents), a genetic disorder of metal metabolism is possible, but we cannot exclude environmental factors.

Child↗
PubMed1996

Kupffer cell erythrophagocytosis and graft-versus-host hemolysis in liver transplantation.

BACKGROUND & AIMS: Graft-versus-host hemolysis (GVHH) syndrome develops in approximately half of patients undergoing ABO-unmatched liver transplantation. The clinical and laboratory presentations of GVHH syndrome often mimic acute rejection, leading to liver biopsy for definitive diagnosis. The purpose of this study was to investigate if there are specific histological findings that permit diagnosis of GVHH syndrome and to assess the relationship between GVHH syndrome and rejection. METHODS: Clinical and laboratory evidence of GVHH syndrome, results of liver biopsy, and clinical outcome were assessed in 30 ABO-unmatched liver transplant recipients. Biopsy results were compared with those of two control groups consisting of patients who had normal liver test findings (protocol biopsy) and rejection. RESULTS: Sixteen of the 30 patients (53%) had evidence of GVHH syndrome. Erythrophagocytosis was noted in each biopsy specimen, and the degree of phagocytosis correlated significantly with the amount of blood given after postoperative day 5 (r = 0.9; P < 0.02). Electron-microscopic studies performed randomly in 5 patients showed that the red cells were located in Kupffer cells. In contrast, erythrophagocytosis was minimal in the two control groups. Despite an incidence and severity of rejection similar to those in other liver transplant patients, serum transaminase levels were significantly higher in patients with GVHH syndrome. CONCLUSIONS: Erythrophagocytosis is a sensitive histological marker of GVHH syndrome. The severity of rejection and response to antirejection therapy should be monitored by markers other than transaminases in patients with GVHH syndrome.

Adult↗
PubMed1996

Lymphocyte targeting of the central nervous system: a review of afferent and efferent CNS-immune pathways.

The central nervous system (CNS) in considered to be an immunological privileged site. However, inflammatory reactions in response to virus infections, in multiple sclerosis (MS) and in experimental autoimmune encephalomyelitis (EAE) suggest that there are definite connections between the CNS and the immune system. In this review, we examine evidence for afferent and efferent pathways of communication between the CNS and the immune system, the pivotal role of regional lymph nodes in T-cell mediated autoimmune disease of the CNS, and the factors involved in lymphocyte targeting of the CNS. Afferent pathways of lymphatic drainage of the brain are well established in a variety of species, especially rodents. Fluid and antigens appear to drain along perivascular spaces populated by immunocompetent perivascular cells. Drainage pathways connect directly via the cribriform plate to nasal lymphatics and cervical lymph nodes. Soluble antigens draining from the brain induce antibody production in the cervical lymph nodes. Using a model of cryolesion-enhanced EAE, we review the role of lymphatic drainage and cervical lymph nodes in the enhancement of cerebral EAE. If a brain wound in the form of a cryolesion is produced 8 days post inoculation (dpi) of antigen in the induction of acute EAE, there is a 6-fold increase in severity of cerebral EAE by 15 dpi. Removal of the cervical lymph nodes significantly reduces such enhancement of EAE. These findings suggest that drainage of antigens from the brain to the cervical lymph nodes, in the presence of activated lymphocytes in the meninges or CNS, results in an enhanced second wave of lymphocytes targeting the brain. In examining the efferent immune pathway by which lymphocytes home to the CNS, several studies have characterized the phenotype of infiltrating T lymphocytes by the use of immunocytochemistry or FACS analysis. T-cells infiltrating the CNS are recently activated/memory lymphocytes typified by their high expression of CD44, LFA-1 and ICAM-1 and low expression of CD45RB in the mouse. Following the induction of EAE in susceptible mice, ICAM-1 and VCAM-1 are dramatically upregulated on CNS vessels; lymphocytes bind to such vessels via the interaction of their known ligands, LFA-1/Mac-1 and alpha 4-integrins, at least in vitro. It appears that alpha 4-integrin plays a key role in lymphocyte recruitment across the blood-brain barrier and may be a major factor in lymphocyte targeting of the CNS. Definition of factors involved in the afferent and efferent connections between the CNS and the immune system may clarify mechanisms involved in immune privilege of the CNS and may open significant therapeutic opportunities for multiple sclerosis.

Afferent Pathways↗
PubMed1996

Loss of resistance to murine hepatitis virus strain 3 infection after treatment with corticosteroids is associated with induction of macrophage procoagulant activity.

Activation of the immune coagulation system has been implicated in the pathogenesis of liver injury following infection of inbred mice with murine hepatitis virus strain 3 (MHV-3). Following MHV-3 infection, macrophages isolated from MHV-3-susceptible and -semisusceptible inbred strains of mice express increased procoagulant activity (PCA), whereas macrophages from resistant strains express no increase in PCA over basal levels. The PCA induced by MHV-3 is a prothrombinase, encoded by the gene Fgl-2, which encodes a fibrinogen-like protein (musfiblp). In this study, MHV-3-resistant A/J mice treated with methylprednisolone prior to infection with MHV-3 developed elevated levels of alanine aminotransferase in serum and died within 10 days of infection, with histological findings of fulminant hepatitis. In vitro, macrophages isolated from A/J mice and pretreated with methylprednisolone produced a marked increase in functional PCA following infection with MHV-3. The PCA was shown to be a prothrombinase by its ability to cleave 125I-prothrombin. Northern blot analysis of RNA transcripts from these macrophages demonstrated increased transcription of the Fgl-2 gene relative to that in macrophages which had not been pretreated with methylprednisolone prior to MHV-3 infection. Methylprednisolone pretreatment of MHV-3-infected macrophages stabilized the Fgl-2 mRNA. Thus, loss of resistance to MHV-3 secondary to methylprednisolone therapy is associated with increased transcription and stability of Fgl-2 mRNA resulting in expression of the Fgl-2 gene product, musfiblp. These results provide further insight into mechanisms of PCA regulation in response to MHV-3 infection in inbred strains of mice.

Animals↗
PubMed1996

Morphometric analysis of gastrocnemius muscle fiber size and fiber proportions in the hypophysectomized rat after prolonged administration of growth hormone or thyroxine.

This study investigated the effects of either growth hormone or thyroxine on muscle fiber atrophy caused by hypophysectomy in male Wistar rats. Muscle fiber size is reported as equivalent circle diameter (ECD) in transverse section of fresh-frozen gastrocnemius muscle. Three months post-hypophysectomy type 1 (slow twitch) and type 2 (fast twitch) muscle fibers were smaller (p < 0.01) than those in intact controls as shown previously in this laboratory. The administration of human growth hormone (GH) (50mIU/100g body weight/day) to hypophysectomized (hypox) rats for 42 days, stimulated body growth, restored 42% of the lost gastrocnemius muscle weight (p < 0.05) and 36% of the lost type 1 fiber size, (p < 0.01), but had no effect on type 2 fiber size. Treatment of hypox rats with physiological doses of thyroxine (5 micrograms T4/100g body weight/alternate day) for 42 days did not affect body growth, gastrocnemius muscle weight or type 1 fiber size, but reduced the size of type 2 fibers (p < 0.01). Thyroxine prevented the decline in the percentage of type 2 fibers which occurs after hypophysectomy. This unique observation suggests that thyroid hormone regulates the proportion of different fiber types in the gastrocnemius muscle. Thus, in hypox rats, GH promoted growth of type 1 or slow twitch muscle fibers needed to support the increasing weight of the growing body. Physiological doses of T4 did not stimulate growth, but caused further atrophy of of type 2 fibers possibly while providing fuel for rapid movement.

Animals↗
PubMed1995

Adaptation of the TdT assay for semi-quantitative flow cytometric detection of DNA strand breaks.

The enzyme Terminal Deoxynucleotidyl Transferase (TdT) is a DNA polymerase which can be used to label DNA strand breaks by the incorporation of a labelled nucleotide followed by a fluorescent detection step. The amount of label incorporated can then be assessed by flow cytometry. The mechanism of action of TdT, however, will allow the addition of varying numbers of nucleotides to the free 3' termini produced by DNA strand breaks. The substitution of Digoxigenin (DIG) labelled dideoxy-nucleotides for labelled deoxy-nucleotides in the TdT assay will limit the addition of label to a DNA break to a single nucleotide, thus ensuring a direct relationship between an increase in DNA strand breaks and an increase in fluorescence. We have used this adaptation of the TdT Assay to evaluate DNA damage incurred in lymphocytes, from patients with Chronic Lymphocytic Leukaemia (CLL), on exposure to UV irradiation and apoptosis-inducing drugs, fludarabine and 2-Chloro-2'-deoxyadenosine (2-CdA). This technique may give a good indication of the susceptibility of CLL patients to apoptosis inducing drugs, and hence an indication of the likely response to these therapies.

Antineoplastic Agents↗
PubMed1995

Behavioral and endocrine responses to clomipramine in panic disorder patients with or without alcoholism.

Central nervous system serotonin functions may differ between certain subgroups of alcoholics, patients with panic disorder, and healthy volunteers. To investigate these possibilities we administered the serotonin uptake inhibitor, clomipramine (12.5 mg, i.v.), to patients with alcohol dependence, patients with panic disorder with or without alcohol dependence, and healthy volunteers. Alcoholics did not differ from healthy volunteers in their neuroendocrine or behavioral responses. In contrast, patients with panic disorder exhibited marked dysphoric reactions and/or panic attacks following low-dose i.v. clomipramine, whereas their neuroendocrine responses were similar to the other two groups. Patients with panic disorder may have super-sensitive postsynaptic serotonin receptors in areas of their central nervous system, which are important for mood regulation.

Adrenocorticotropic Hormone↗
PubMed1995

Role of neutrophils in mediating human epithelial cell detachment from native basement membrane.

Epithelial cell detachment from underlying basement membrane is a feature of diseases of many organs. In the lungs it is seen in disorders as diverse as bronchiectasis, allograft rejection, and asthma. The potential for different leukocytes to induce this change is not clear. In asthma both eosinophils and neutrophils are found in affected tissues, but the capacity of each of these types of cells to induce detachment of native epithelial cells from basement membrane requires clarification. Although eosinophils damage rather than detach human epithelial cells, the effects of neutrophils on epithelial cells naturally attached to basement membrane have not previously been described. Using the human amnion in vitro model, we tested the hypothesis that neutrophils have the capacity to detach intact human epithelial cells from basement membrane. The data indicate that increasing concentrations of neutrophils are able to detach epithelial cells from their underlying basement membrane. Detachment was increased when the neutrophils were activated in situ with tetradecanoyl phorbol acetate and after longer incubation periods. Platelet activating factor and opsonized zymosan showed similar boosting effects, whereas activated complement and formyl-methyl-leucyl-phenylalanine did not. Physical contact of the neutrophils with the epithelial cells was required to induce detachment. Detachment could be inhibited by glutathione and by soybean trypsin inhibitor, an inhibition pattern similar to cathepsin G and trypsin, but not collagenase, in this system. We conclude that neutrophils are capable of detaching human epithelial cells from basement membrane, which in part involves the release of chymotrypsin-like serine proteases, probably in conjunction with oxidants, and that this detachment can be inhibited.

Amnion↗
PubMed1995

Focal brain damage enhances experimental allergic encephalomyelitis in brain and spinal cord.

The immunological basis of multiple sclerosis (MS) is well recognized but the factors inducing MS lesions are unclear. In this study, we test the hypothesis that focal brain injury, inflicted during the pre-clinical stages of experimental allergic encephalomyelitis (EAE), will enhance the severity of immunological damage in the cerebral hemispheres and spinal cord. Acute EAE was induced in 30 Lewis rats by the injection of guinea pig spinal cord homogenate in complete Freund's adjuvant. A cryolesion to the surface of the left cerebral hemisphere was induced at 3 days (n = 6) or 8 days (n = 10) postinoculation (p.i.) and animals were killed at 15 days p.i. Control animals were EAE only (n = 9), cryolesion only (n = 4), EAE and sham cryolesion (n = 5) and normal animals (n = 3). Brain and spinal cord were stained by immunocytochemistry using W3/13 (T-lymphocytes) OX6 (MHC Class II) and GFAP (astrocytes) antibodies. The results showed a 2-fold increase in the number of EAE lesions in the brain with significant and widespread increase of MHC Class II antigen expression by microglia, in the cryolesion EAE 8 days p.i. when compared with EAE only animals. The pattern of enhancement suggests that it is due to (i) local spread of tissue or serum factors from the cryolesion; (ii) neural factors affecting remote regions of the CNS; (iii) stimulation of the immune system which may occur due to products of brain injury draining to regional cervical lymph nodes. Investigation of the mechanisms involved may prove fruitful in establishing factors which initiate, aggravate or ameliorate brain damage in multiple sclerosis.

Animals↗
PubMed1995

A rapid and reliable PCR method for detecting clonal T cell populations.

Aims-To establish a reverse transcription polymerase chain reaction (RT-PCR) for the detection of clonal T cell populations, and to evaluate the sensitivity and reliability of the technique.Methods-After reverse transcription of the target RNA with a consensus T cell receptor (TCR) beta constant (C) region primer, consensus C, variable (V), diversity (D) and joining (J) region primers were used to amplify across various portions of the TCRbeta V-D-J-C junction.Results-In normal T cells the polyclonal rearrangements produce a ladder of PCR bands representing the different sized junction fragments. The presence of a T cell clone leads to over-representation of one junction fragment, hence a disproportionately brighter band in the PCR ladder. In a series of 16 patients the RT-PCR detected nine of nine shown to have a clonal TCRbeta rearrangement by Southern blotting and for six of seven patients, it confirmed the presence of a clone indicated by histology or immunophenotyping with FACS analysis, but which was undetectable (five patients) or not investigated (two patients) by Southern blotting. Investigations mixing RNA from normal lymphocytes and the Jurkat TCR-Vbeta8 T cell line suggested that the method was more sensitive than Southern blotting.Conclusions-All PCR methods are faster and easier than Southern blotting, but RT-PCR also improves detection of clonal T cell populations, is reliable and produces results that are easy to interpret.

Journal Article↗