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J Pollock

Publications and source records attributed to J Pollock.

At least 19 recordsLinked to original sources
PubMed1999

Identification and functional characterization of the murine Rac2 gene promoter.

Rac2, a member of the Rho family of GTPases, is highly expressed in myeloid cells and is a regulator of the NADPH-oxidase complex. A murine genomic clone was isolated that contains the 5' end and putative promoter region of the Rac2 gene. Ribonuclease protection experiments detected 13 transcription initiation sites scattered 50 to 130 bp upstream of the translation initiation site. Transient transfection studies revealed that -7 kb to +31 bp (relative to the strongest transcription initiation site) of the Rac2 gene 5'-flanking region exhibited strong promoter activity in both RAW 264.7 macrophage cells that express the endogenous Rac2 gene and NIH-3T3 fibroblast cells that do not express the endogenous gene. Truncated Rac2 promoter fragments containing as little as the -74 to +31 bp sequence produced full transcriptional activity. However, a -57 to +31 promoter fragment directed significantly less transcription, and a -39 to +31 promoter fragment was transcriptionally inactive. In vitro binding assays revealed sequence-specific and widely expressed DNA-binding activities that interacted within the -74 to -58 Rac2 promoter cis element. Oligonucleotide competition and antibody disruption studies indicated that these complexes contained the transcription factors Spl and Sp3. Specific ablation of the Sp1/Sp3 binding site significantly decreased Rac2 promoter activity in both RAW 264.7 and NIH-3T3 cells. Additional cis elements may be required to restrict Rac2 promoter activity to hematopoietic cells expressing the endogenous gene.

3T3 Cells↗
PubMed1998

Transgenically produced human antithrombin: structural and functional comparison to human plasma-derived antithrombin.

Recombinant human antithrombin (rhAT) produced in transgenic goat milk was purified to greater than 99%. The specific activity of the rhAT was identical to human plasma-derived AT (phAT) in an in vitro thrombin inhibition assay. However, rhAT had a fourfold higher affinity for heparin than phAT. The rhAT was analyzed and compared with phAT by reverse phase high-performance liquid chromatography, circular dichroism, fluorophore-assisted carbohydrate electrophoresis (FACE), amino acid sequence, and liquid chromatography/mass spectrography peptide mapping. Based on these analyses, rhAT was determined to be structurally identical to phAT except for differences in glycosylation. Oligomannose structures were found on the Asn 155 site of the transgenic protein, whereas only complex structures were observed on the plasma protein. RhAT contained a GalNAc for galactose substitution on some N-linked oligosaccharides, as well as a high degree of fucosylation. RhAT was less sialylated than phAT and contained both N-acetylneuraminic and N-glycolylneuraminic acid. We postulate that the increase in affinity for heparin found with rhAT resulted from the presence of oligomannose-type structures on the Asn 155 glycosylation site and differences in sialylation.

Animals↗
PubMed1998

High expression of endothelial nitric oxide synthase in plexiform lesions of pulmonary hypertension.

The pathogenesis of pulmonary hypertension (PH) remains poorly understood. Vasoconstriction, although likely to be a major factor in the disease, varies between patients and studies of a variety of vasoactive substances have sometimes yielded conflicting results. Amongst these substances, alteration of the nitric oxide (NO) system has been cited as a possible pathogenic factor but both reduction and elevation of the expression of endothelial NO-synthase (eNOS) have been reported in pulmonary vessels. The present study has used immunocytochemistry with well-characterized antibodies to eNOS to investigate its expression in lung tissue taken at transplantation from 44 patients with PH (22 primary, 22 secondary) and 12 non-hypertensive controls. Semi-quantitative assessment showed that although the levels of eNOS expression in pulmonary vessels were variable within both hypertensives and controls, a statistically significant (P < 0.01) reduction of immunoreactivity was found in small arterioles from hypertensives compared with controls. In contrast, consistently strong expression of eNOS was seen in the endothelium of plexiform lesions in both the primary and the secondary PH patients. Although a decrease in the NO system of patients with PH has been reported, these findings show a distinct regional distribution of the enzyme with particularly high levels in plexiform lesions, a previously unreported observation, and offer a new perspective on the disease and on the evaluation of possible novel therapeutic approaches.

Adolescent↗
PubMed1998

Extracellular or intracellular application of argiotoxin-636 has inhibitory actions on membrane excitability and voltage-activated currents in cultured rat sensory neurones.

The whole cell variant of the patch clamp technique was used to investigate the actions of the polyamine amide spider toxin, argiotoxin-636, on the excitability of cultured dorsal root ganglion neurones. Synthesized argiotoxin-636 (0.1-100 microM) reduced neuronal excitability when applied to the extracellular environment by low pressure ejection or to the intracellular environment via the patch pipette solution. The toxin prolonged the duration of evoked action potentials and reduced the peak amplitude of action potentials. Intracellular and extracellular application of argiotoxin-636 also decreased the number of action potentials evoked in response to 800-ms depolarizing current commands. This action of the toxin was mimicked by 100 microM tetraethylammonium. Extracellular application of argiotoxin-636 inhibited voltage-activated K currents in a dose-dependent manner over the complete voltage range. This inhibition occurred without any significant changes in the voltage dependence of activation or inactivation. Intracellular application of argiotoxin-636, during 5-10 min of whole cell recording, also inhibited voltage-activated K+ currents without changing the voltage dependence of activation or steady-state inactivation. Extracellular or intracellular spermidine (250 microM) reversibly attenuated the inhibitory actions of extracellular argiotoxin-636. Argiotoxin-636 also inhibited voltage-activated Na + currents; this effect was dependent on repeated activation of the currents and the period during which the neurones were in culture. We conclude that application of argiotoxin-636 to either the extracellular or intracellular environment reduced excitability of cultured sensory neurones from neonatal rats and that this involved inhibition of both voltage-activated K+ and Na+ currents. The data suggest that the toxin was more effective at attenuating action potentials when neurones were repeatedly excited, and that access to inhibitory sites of action on the voltage-activated ion channels can be achieved from the inside of the neurone.

Action Potentials↗
PubMed1998

Sudden death 10 years after patch aortoplasty for coarctation.

A 25-year-old man died 10 years after a Dacron patch was used to repair a coarctation of the aorta. Death was due to rupture of an unrecognized aneurysm at the site of the patch. After the initial operation at the age of 15 years, there had been no signs of residual or recurrent obstruction. He had no evidence of hypertension and was discharged some years later from regular hospital follow-up to the care of his general practitioner. We strongly recommend that patients who have undergone repair of aortic coarctation by patch aortoplasty should have lifelong follow-up in cardiac units with imaging facilities for monitoring aortic dilation. We would now recommend surgical intervention in the presence of progressive aortic dilation.

Adult↗
PubMed1998

Intracranial osteosarcomas: report of four cases and review of the literature.

Four cases of intracranial osteosarcoma are reported. In three cases the tumors were primary neoplasms arising from the sellar region, base of the occiput and the parieto-occipital area. One case represented osteosarcoma metastatic to the cerebellum, a site not previously described, from a primary tumor at the femur. In addition, the current literature on intracranial osteosarcoma is reviewed.

Adult↗
PubMed1998

Outcomes of transposition of the great arteries in the ear of atrial inflow correction.

OBJECTIVE: To examine long term morbidity and mortality following atrial inflow corrective procedures for transposition of the great arteries (TGA) and to investigate factors that influence morbidity and mortality. DESIGN: Retrospective cohort study from a single centre. SETTING: Cardiology and cardiothoracic surgical unit in a large tertiary referral centre. PATIENTS: All 130 patients who had TGA diagnosed between August 1972 and May 1988 and were considered suitable for atrial inflow correction; 109 of these underwent surgery (operative cohort: 84 Mustard operations and 25 Senning operations); 95 survived to hospital discharge (hospital surviving cohort). MAIN OUTCOME MEASURES: Death and cardiac events. RESULTS: There were relatively good long term results from atrial inflow correction for TGA with 5, 10, and 15 year survivals of 77.3%, 75.9%, and 71.3%. However, there was an appreciable incidence of late cardiac death and events, with 5, 10, and 15 year cardiac event-free survivals of 74.5%, 67.1%, and 39.6%. Supraventricular tachycardia was the only significant risk factor for late cardiac death (relative risk 8.72, 95% confidence interval, 2.86 to 26.64). Senning patients had better event-free survival (p = 0.04). CONCLUSIONS: Atrial inflow correction for TGA has a reasonably good 15 year survival (71.3%), but there is an appreciable incidence of late cardiac deaths and events (15 year event-free survival 39.6%). The Senning procedure is preferable to the Mustard procedure for cases unsuitable for arterial switching.

Adolescent↗
PubMed1998

The role of pharmacists in HIV/STD prevention: evaluation of an STD syndromic management intervention in Nepal.

OBJECTIVE: To evaluate the effects of a pilot sexually transmitted disease (STD) syndromic case management training for pharmacists in Nepal on STD drug dispensing behavior, HIV/STD prevention communication, and condom promotion and sales. METHODS: Pre- and post-intervention interviews with samples of 160 pharmacists were conducted utilizing the simulated client method to collect data on pharmacists' response to men reporting urethral discharge. In order to assess the long-term effects, a sub-sample of 38 pharmacists trained 7-9 months before the follow-up survey was analysed separately. RESULTS: There were no significant differences in the percentages of pharmacists who suggested taking medications, dispensed medications, or referred clients to a physician. The proportion of pharmacists who recommended an injection declined from 27% to 14%. Prior to the intervention, only one pharmacist (0.8%) dispensed the correct drugs and regimen for the syndromic treatment of urethritis. This increased to 45% immediately following the training. In a sub-sample of pharmacists who were interviewed 7-9 months after the training, the correct drugs and regimen were dispensed by 26%. The proportion of pharmacists who recommended to clients to have their sex partners treated increased from 5% to 21%. Although the proportion of pharmacists who suggested condom use increased from 14% to 24%, the proportion of pharmacists actually selling a condom or giving advice on HIV testing remained low and unchanged pre- and post-intervention. Over one-third of pharmacists mentioned HIV or AIDS in their interactions with clients, compared to 9% prior to the intervention. CONCLUSIONS: The findings suggest that STD services provided by pharmacists can be significantly improved through a short-term training intervention, although the improvements are modest and probably time-limited. Interventions must be more intensive and combined with regular follow-ups if they are to meet their desired goals of improving STD treatment in a pharmacy setting.

Anti-Infective Agents↗
PubMed1997

Farm worker injuries associated with bulls. New York State 1991-1996.

1. Although cows greatly outnumber bulls on dairy farms, bulls account for 25% of animal related injuries in a surveillance study of agricultural injury. In addition, bull injuries are more severe. 2. Because of their size and unpredictable behavior, bulls, especially those over 18 months of age, must be handled with extreme caution. 3. Important risk factors for the observed incidents were working alone and not having an escape route. 4. Bulls should be dehorned and confined in specially designed facilities to avoid human contact during feeding, watering, exercising, or breeding.

Accidents, Occupational↗
PubMed1997

Farm worker injuries associated with cows. New York State 1991-1996.

1. The size of cows and their unpredictable behavior constitute a hazard for workers who handle them. 2. When cows are startled by sudden movements and unfamiliar situations, they may kick, push, knock down, fall, or step on workers. 3. Cows in heat or those with calves are particularly excitable. Working in confining situations, such as milking stalls, exacerbates the danger of injury to handlers. 4. Knowledge of effective animal handling techniques and well designed handling facilities can reduce the incidence of injury.

Adolescent↗
PubMed1996

Reexpression of morphine-induced oral stereotypy six months after last morphine sensitizing dose.

We describe three experiments, two of which were designed to determine the duration of the sensitization to morphine-induced oral stereotypy caused by three high doses of morphine (MS) administered 12 h apart (10, 20, and 20 mg/kg). In one of these experiments, we also administered an additional 40 mg/kg. The third experiment was designed to determine the role of mode of drug administration in the development of MS-induced sensitization; drug was delivered by an implanted minipump. By the third high dose, all rats manifested marked repetitive gnawing and biting behavior. The stereotypy was reexpressed up to over 300 days in repeatedly challenged animals and up to at least 180 days in animals receiving only one MS challenge. The development of sensitization was not altered by the mode of drug administration.

Animals↗
PubMed1996

Effect of porcine circovirus infection on porcine alveolar macrophage function.

The effect of porcine circovirus (PCV) infection of porcine alveolar macrophage cultures on some of the functional properties of these cells are reported. PCV infection of alveolar macrophages did not effect their ability to phagocytose and kill complement-coated yeast cells or the expression of Fc or complement receptors. A transient increase in major histocompatibility complex (MHC) class I expression in PCV-infected cells were observed 4 days after infection and a decrease in the number of cells expressing MHC class II antigens was observed 8 days after infection. Infection of alveolar macrophages with PCV also resulted in a transient decrease in their ability to act as accessory cells in mitogen-induced lymphocyte proliferation of monocyte-depleted porcine peripheral blood mononuclear cells.

Animals↗
PubMed1994

Expression of nitric oxide synthase immunoreactivity by interstitial cells of the canine proximal colon.

A subpopulation of interstitial cells (ICs) are interposed between nerve terminals and smooth muscle cells in the gastrointestinal tract and may participate in neuromuscular transmission. These cells appear to be targets for NO released from enteric inhibitory nerves and respond to exogenous NO with: (i) an elevation in cGMP levels; (ii) an increase in intracellular Ca2+; (iii) and release of a diffusible substance that has tentatively been identified as NO. For the latter to be possible, ICs must express a constitutive isoform of NOS. This study characterized the expression of NOS-like immunoreactivity (NOS-LI) in ICs of the canine colon using 3 antibodies raised against the 2 known constitutive forms of NOS (i.e., neural (nNOS) and endothelial (eNOS) isoforms). Antibodies raised against cNOS and an antibody raised against rat cerebellar nNOS labeled ICs along the submucosal surface of the circular muscle layer (IC-SM), along the surface of septa that separate the circular muscle into fiber bundles (IC-SM), and in the myenteric region between the circular and longitudinal muscle layers (IC-MY). Another antibody raised against rat cerebellar nNOS failed to label ICs. Cultured IC-SM also expressed NOS-LI, suggesting that this feature of the IC phenotype survives culture conditions. Arteriolar endothelial cells in the canine colon were labeled with the same 2 antibodies that labeled ICs, suggesting there are significant structural similarities between NO synthases in ICs and endothelial cells. The data suggest that IC-SM and IC-MY express a constitutive form of NOS. Synthesis of NO by ICs may influence electrical rhythmicity and may serve to amplify and even propagate enteric inhibitory neurotransmission.

Amino Acid Oxidoreductases↗
PubMed1993

Sequence of the proteinase-inhibitor cystatin homologue from the pollen of Ambrosia artemisiifolia (short ragweed).

The nucleotide sequence of a cDNA (designated IPC1/5) encoding a cystatin (Cyt) proteinase-inhibitor homologue from short ragweed (Ambrosia artemisiifolia) pollen was determined and compared to other plant and animal Cyt. The absence of disulfide bonds in the predicted translation product of the IPC1/5 sequence suggests that it most resembles family-I members of the Cyt superfamily. Significant amino acid (aa) sequence identity was found when comparing the translated sequence of IPC1/5 to rice seed Cyt, human keratocyte Cyt A and human liver Cyt B.

Allergens↗
PubMed1993

Comparison of midazolam with propofol for sedation in outpatient bronchoscopy.

We have compared sedation for fibreoptic bronchoscopy provided by incremental doses of midazolam with that provided by a computer-controlled infusion of propofol. These two methods were compared in terms of operator and patient acceptability, anxiolysis, effects on systolic arterial pressure and oxygen saturation. Tests were made also of memory and motor reactions, before and 60 min after the end of the procedure. Acceptability to operators and patients was high in both groups. There were no significant differences between the groups in systemic arterial pressure or anxiolysis. Oxygen saturation decreased in both groups (propofol group median 83% (range 69-95%); midazolam group median 86% (range 77-95%)) (ns). The median recovery time was 5 min (range 5-10 min) in the propofol group and 10 min (range 5-40 min) in the midazolam group (P < 0.01). Memory and motor reaction times 60 min after the end of the procedure did not differ from baseline in the propofol group, but were significantly impaired in the midazolam group.

Adult↗