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Biomedical subjects

H Parry

Publications and source records attributed to H Parry.

At least 19 recordsLinked to original sources

Endoplasmic reticulum generates calcium signalling microdomains around the nucleus and spindle in syncytial Drosophila embryos.

Cell cycle calcium signals are generated by inositol trisphosphate-mediated release of calcium from internal stores [Ciapa, Pesando, Wilding and Whitaker (1994) Nature (London) 368, 875-878; Groigno and Whitaker (1998) Cell 92, 193-204]. The major internal calcium store is the ER (endoplasmic reticulum): the spatial organization of the ER during mitosis is important in defining a microdomain around the nucleus and mitotic spindle in early Drosophila embryos [Parry, McDougall and Whitaker (2005) J. Cell Biol. 171, 47-59]. Nuclear divisions in syncytial Drosophila embryos are accompanied by both cortical and nuclear localized calcium transients. Mitosis is prevented by the InsP(3) antagonists Xestospongin C and heparin. Nuclear-localized transients and cortical transients rely on extraembryonic calcium, suggesting that ER calcium levels are maintained by calcium influx.

Animals↗

Identification of a fibrinolytic enzyme in Schistosoma mansoni eggs and modulated blood fibrinogen metabolism in S. mansoni-infected mice.

Aqueous extracts of Schistosoma mansoni eggs have been shown to have fibrinolytic activity inhibitable by a serine protease inhibitor. Fibrinolytic activity was not present in extracts of either adult worms or cercariae. A 27 kDa enzyme that was proteolytically active on fibrinogen in zymography and that degraded fibrinogen in a pattern similar to that of plasmin, is presumed to be responsible for the schistosome egg fibrinolytic activity. Anti-human fibrinogen antisera were shown to have antibodies that cross-reacted with mouse fibrinogen in Western immunoblots. Electroblotted sera from S. mansoni-infected and control uninfected mice displayed different antigenic profiles when probed with the cross-reactive anti-human fibrinogen antibodies, suggesting an alteration in mouse host fibrinogen metabolism as a result of the parasitic infection. We discuss the possibility that modulation of fibrinogen metabolism is a factor in a recently discovered anti-atherogenic effect exerted by schistosomes.

Animals↗

Immune-dependent thrombocytopaenia in mice infected with Schistosoma mansoni.

As has been shown previously, immunologically intact mice with patent Schistosoma mansoni infections had a significantly lower mean platelet number than intact uninfected mice (P<0.0001). However, platelet numbers in T-cell deprived mice with patent infections were not significantly different from those in uninfected T-cell deprived mice. Also, platelet counts in both the infected and uninfected T-cell deprived groups were not significantly different from those in intact uninfected mice. The S. mansoni-induced thrombocytopaenia in mice is thus seemingly immune dependent. Immunologically intact mice with chronic 12-week-old S. mansoni infections had IgG antibodies that were reactive in an ELISA-type assay with whole fixed platelets of both mouse and human origin. In Western immunoblots the IgG antibodies from chronically-infected mice reacted in particular against mouse and human platelet antigens of 90, 37 and 30 kDa. Antisera raised from 2 rabbits, immunized respectively with mouse and human platelet antigens, cross-reacted with antigens of the larval, adult worm and egg stages of S. mansoni. These results support the hypothesis that an anti-platelet antibody response may be the cause of the thrombocytopaenia observed in mice with patent schistosome infections.

Animals↗

Spinal cord damage.

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Analgesia, Epidural↗

Effect of cigarette smoking on levels of bioavailable testosterone in healthy men.

The effect of smoking on androgen levels is important given the recent interest in the link between low levels of androgens and the development of cardiovascular disease. Numerous studies examining the effects of cigarette smoking on the levels of total and free testosterone have reported conflicting findings, but there has been no accurate assessment of the effects of cigarette smoking on the levels of bioavailable testosterone [not bound to sex hormone-binding globulin (SHBG)]. We attempted to determine whether smoking affects the level of bioavailable testosterone. We undertook a case-control study of 25 healthy male smokers and 25 healthy never-smokers, matched by age and body mass index. Early morning levels of total, free and bioavailable testosterone, 17beta-oestradiol, SHBG and cotinine were determined and compared between the two groups. Levels of total (18.5+/-4.6 nM versus 15.1+/-4.9 nM, P=0.01) and free testosterone (462+/-91 pM versus 402+/-93 pM, P=0.03) were found to be higher in smokers compared with non-smokers respectively, as was SHBG (34.1+/-12.8 versus 28.1+/-9.0 nM, P=0.06). There were no significant differences in the levels of bioavailable testosterone (3.78+/-1.59 versus 3.51+/-1.26 nM, P=0.49) or 17beta-oestradiol (44.5+/-11.4 versus 42.3+/-11.5 pM, P=0.50) between smokers and non-smokers respectively. These data suggest that cigarette smoking has no significant effect on the biologically active fraction of testosterone, but may influence the levels of total and free testosterone through changes in the levels of SHBG.

Adolescent↗

Smoking, alcohol consumption, and leukocyte counts.

Blood was collected from 684 healthy volunteers and examined for total and differential white blood cell (WBC) counts. A subgroup also was tested for numbers of T cells, B cells, and CD4 and CD8 subsets. Smoking status and alcohol consumption were determined by means of questionnaire, and smoking status was verified with serum cotinine concentration. High smoking rate was associated with increases in all counts. Former smokers abstinent less than 5 years still demonstrated elevated counts, whereas those abstinent more than 5 years had WBC counts comparable to those in persons who were never smokers. Compared with levels in those who had never smoked, total WBC counts were 27% higher in current smokers and 14% higher in former smokers who were abstinent for less than 5 years. Lymphocyte counts were 9% higher in those consuming more than one alcoholic drink per day than in those consuming less alcohol, but drinking was not associated with other cell populations.

Adult↗

Regulation of nitric oxide synthesis by dimethylarginine dimethylaminohydrolase.

1. Dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that metabolizes the endogenous nitric oxide synthase inhibitors NG-monomethyl-arginine and NG,NG-dimethy-L-arginine to citrulline, was identified by Western blotting in rat and human tissue homogenates. 2. S-2-amino-4(3-methylguanidino)butanoic acid (4124W) inhibited the metabolism of [14C]-NG-monomethyl-L-arginine to [14C]-citrulline by rat liver homogenates (IC50 416 +/- 66 microM; n = 9), human cultured endothelial cells (IC50 250 +/- 34 microM; n = 9) and isolated purified dimethylarginine dimethylaminohydrolase. 3. Addition of 4124W to culture medium increased the accumulation of endogenously-generated NG,NG-dimethy-L-arginine in the supernatant of human cultured endothelial cells from 3.1 +/- 0.3 to 5 +/- 0.7 microM (n = 15; P < 0.005). 4. 4124W (1 microM - 1 mM) had no direct effect on endothelial nitric oxide synthase activity but caused endothelium-dependent contraction of rat aortic rings (1 mM 4124W increased tone by 81.5 +/- 9.6% of that caused by phenylephrine 100 nM). This effect was reversed by L-arginine (100 microM). 4124W reversed endothelium-dependent relaxation of human saphenous vein (19.2 +/- 6.7% reversal of bradykinin-induced relaxation at 1 mM 4124W). 5. These data suggest that inhibition of dimethylarginine dimethylaminohydrolase increases the intracellular contraction of NG,NG-dimethyl-L-arginine sufficiently to inhibit nitric oxide synthesis. Inhibiting the activity of DDAH may provide an alternative mechanism for inhibition of nitric oxide synthases and changes in the activity of DDAH could contribute to pathophysiological alterations in NO generation.

Amidohydrolases↗

Mutations in aurora prevent centrosome separation leading to the formation of monopolar spindles.

We show that female sterile mutations of aurora (aur) are allelic to mutations in the lethal complementation group ck10. This lies in a cytogenetic interval, 87A7-A9, that contains eight transcription units. A 250 bp region upstream of both aur and a divergent transcription unit corresponds to the site of a specific chromatin structure (scs') previously proposed to be a barrier to insulate enhancers of the major hsp70 gene at 87A7. Syncytial embryos derived from aur mothers display closely paired centrosomes at inappropriate mitotic stages and develop interconnected spindles in which the poles are shared. Amorphic alleles result in pupal lethality and in mitotic arrest in which condensed chromosomes are arranged on circular monopolar spindles. The size of the single centrosomal body in these circular figures suggests that loss of function of the serine-threonine protein kinase encoded by aur leads to a failure of the centrosomes to separate and form a bipolar spindle.

Alleles↗

The 190 kDa centrosome-associated protein of Drosophila melanogaster contains four zinc finger motifs and binds to specific sites on polytene chromosomes.

Microinjection of a bacterially expressed, TRITC labelled fragment of the centrosome-associated protein CP190 of Drosophila melanogaster, into syncytial Drosophila embryos, shows it to associate with the centrosomes during mitosis, and to relocate to chromatin during interphase. Indirect immunofluorescence staining of salivary gland chromosomes of third instar Drosophila larvae, with antibodies specific to CP190, indicate that the protein is associated with a large number of loci on these interphase polytene chromosomes. The 190 kDa CP190 protein is encoded by a 4.1 kb transcript with a single, long open reading frame specifying a polypeptide of 1,096 amino acids, with a molecular mass of 120 kDa, and an isoelectric point of 4.5. The central region of the predicted amino acid sequence of the CP190 protein contains four CysX2CysX12HisX4His zinc-finger motifs which are similar to those described for several well characterised DNA binding proteins. The data suggest that the function of CP190 involves cell cycle dependent associations with both the centrosome, and with specific chromosomal loci.

Amino Acid Sequence↗

P-COMM-B induction chemotherapy in intermediate and high grade non-Hodgkin's lymphoma.

57 patients with newly diagnosed intermediate or high grade non-Hodgkin's lymphoma with stage II to IV disease were treated with P-COMM-B (prednisolone, cyclophosphamide, vincristine, mitozantrone, methotrexate and bleomycin). 46% patients achieved a complete remission and 26% achieved a partial remission. Projected disease-free survival in complete remission at 5 years is 56% and projected overall survival at 5 years is 37%. Neutropenia and proximal myopathy were the commonest severe toxicities encountered and two deaths were clearly related to treatment (3.5%). P-COMM-B is effective first-line chemotherapy in intermediate and high grade non-Hodgkin's lymphoma. The efficacy and toxicity of P-COMM-B appear to be comparable to those of the best contemporary regimen, CHOP.

Adolescent↗

Evidence that interleukin-4 suppression of lymphokine-activated killer cell induction is mediated through monocytes.

Recombinant human interleukin-4 (IL-4) and transforming growth factor-beta (TGF-beta) reduce recombinant interleukin-2 (IL-2) induction of lymphokine-activated killer (LAK) cell activity from human peripheral blood mononuclear cells (PBMC). Monocytes can be removed from PBMC by adherence, leaving a peripheral blood lymphocyte population (PBL) which also responds to IL-2 to generate LAK activity. PBL generation of LAK cytotoxicity is susceptible to inhibition by TGF-beta, but not by IL-4. Readdition of purified monocytes to PBL is accompanied by return of the suppressive action of IL-4 on the generation of LAK activity. Induction of LAK cytolysis from Percoll-isolated T cells (greater than 90% CD3+) is also refractory to the inhibitory effect of IL-4. When PBMC were cultured in IL-2, with and without IL-4, subsequent sorting of CD3+ and CD3- lymphocytes by flow cytometry demonstrated that IL-4 had suppressed LAK induction in both effector populations. This suggests that, although isolated CD3+ cells are not susceptible to IL-4 suppression of IL-2 activation, they are sensitive to inhibition when part of a mixed PBMC population. Evidence is presented for the first time that this suppression is mediated via the action of IL-4 on monocytes.

Cell Adhesion↗

Single-dose i.v. dexamethasone--an effective anti-emetic in cancer chemotherapy.

We conducted a randomised, single-blind, placebo-controlled crossover study to assess the efficacy of a single i.v. dose of 20 mg dexamethasone as an anti-emetic in 31 patients receiving cancer chemotherapy. Patients receiving dexamethasone experienced significantly less nausea and vomiting (P less than 0.001 and P less than 0.01, respectively), and appetite and activity were normal in a majority of the treated group. Side effects were insignificant. We conclude that single-dose dexamethasone given i.v. at a dose of 20 mg is a safe and effective anti-emetic for patients receiving cancer chemotherapy excluding cisplatin.

Adult↗

Bacterial meningitis following spinal anaesthesia for caesarean section.

We report a case of meningitis caused by inadvertent introduction of bacteria following spinal anaesthesia for Caesarean section. The technique of performing the spinal anaesthesia is reviewed. Meningitis may occur, although very rarely, despite meticulous aseptic techniques. It is vital that meningitis should be considered in the differential diagnoses of post-spinal headache when patients present with headaches, pyrexia and meningism in the postoperative or postpartum period.

Adult↗

VIM-D salvage chemotherapy in Hodgkin's disease.

A total of 15 patients with relapsed or resistant Hodgkin's disease were treated with a combination of etoposide (VP16), ifosfamide, mitozantrone and dexamethasone (VIM-D). The regime was well tolerated, the only major toxicity being myelosuppression. Complete remissions (CRs) were obtained in 4 patients and were maintained for 2, 4, 10 and 14 months. 10 subjects subsequently received an autologous bone marrow transplant with high-dose chemotherapy (ABMT). Previous exposure to VIM-D did not appear to predict for or prejudice the response to subsequent ABMT.

Adult↗

Early mobilisation of patients with cervical cord injury using the halo brace device.

The halo brace device for cervical spine stabilisation has been in use predominantly in North America since 1959. It has not yet found widespread use for the management of the spinal cord injured in the UK. At the Yorkshire Regional Spinal Injuries Unit we have used the device over 2 years on 20 patients with complete and incomplete traumatic cervical spinal cord injuries, and compared our results with those for the previous 20 patients with similar injuries treated with skull calipers and bed rest. Patients using a halo brace device begin more active rehabilitation earlier as they are mobilised on average 5 weeks earlier than those whose traction is administered via skull calipers. Halo brace patients begin weekend leave usually within 7 weeks of their injury compared to 14 weeks post-injury for caliper treated patients and were discharged on average 2 months earlier than the comparison group. We believe that earlier mobilisation, weekend leave and discharge for halo brace patients in the absence of any neurological deterioration afford significant physical, psychological and management benefits.

Bed Rest↗

Quadriplegic care: an assessment of the impact of the carer.

Thirty-three voluntary carers living with dependent quadriplegics completed a questionnaire survey which recorded their views on the assistance they received. Disruption to sex life, wheelchair restrictions, personality change in the quadriplegic person, and problems with bladder care were the features they most disliked. We have introduced a self-help group. Respite care would assist them with the valuable service they provide at considerable personal cost.

Activities of Daily Living↗