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Biomedical subjects

J Proctor

Publications and source records attributed to J Proctor.

At least 19 recordsLinked to original sources
PubMed2006

Effects of alveolar macrophage depletion on liposomal vaccine protection against respiratory syncytial virus (RSV).

Little is known about the identities and roles of antigen-presenting cells upon exposure to antigens of respiratory syncytial virus (RSV). Here, we focused on elucidating the importance of alveolar macrophages in conferring protective immunity in mice administered a liposome-encapsulated recombinant fragment of the RSV G protein. Mice were depleted of alveolar macrophages by intranasal inoculation of liposome-encapsulated dichloromethylenediphosphonic acid (DMDP). Mice depleted of alveolar macrophages prior to immunization developed reduced levels of serum RSV-neutralizing antibody and showed dramatically impaired protection against RSV challenge. The severity of interstitial inflammation was also markedly reduced in macrophage-depleted mice. In conclusion, this study demonstrates a pivotal role for alveolar macrophages during exposure to liposome-encapsulated RSV antigen in initiating both protective and histopathological responses against RSV.

Animals↗
PubMed2002

Tumour necrosis factor-alpha polymorphism and the HLA-Cw*0602 allele in psoriatic arthritis.

OBJECTIVES: To investigate polymorphisms in the genes for tumour necrosis factor alpha (TNFA), interleukin 10 (IL10) and tumour necrosis factor receptor II (TNFRII) in patients with psoriatic arthritis (PsA) and their relationship to the HLA-Cw*0602 allele and to the ages at onset of psoriasis and arthritis and the pattern of joint involvement. METHODS: One hundred and twenty-four well-characterized patients with PsA were studied. Controls were 101 cadaveric organ donors. All were genotyped for single-nucleotide polymorphisms in TNFA (positions -308, -238, +488), IL10 (-1082, -819, -592) and in the 3'-untranslated region of TNFRII (+1663, +1668, +1690). The HLA-Cw*0602 allele was detected by polymerase chain reaction-based techniques. The frequencies of the respective variants were compared between patients and controls and in relation to the ages at onset of psoriasis and arthritis, to clinical subsets of the disease and to the presence of erosions. RESULTS: HLA-Cw*0602 was significantly increased in frequency in PsA (40 vs 26%; P<0.05) and was associated with younger age of onset of psoriasis (P<0.05). There was no significant increase in any of the polymorphisms studied within TNFA, IL10 or TNFRII in the total PsA group. Although the frequency of TNFA allele -238A was not increased in the total PsA group or in patients with a younger age of onset of psoriasis, TNFA allele -238A was absent in the spondyloarthritis group and increased in frequency in patients with peripheral polyarthritis. However, these latter findings could be explained by linkage disequilibrium as all TNFA -238A alleles (23/23) in patients with PsA were HLA-Cw*0602-positive (P<0.0001). CONCLUSIONS: An association between young age of onset of psoriasis and HLA-Cw*0602 is confirmed in patients with PsA. The uncommon TNFA -238A allele is strongly linked to HLA-Cw*0602 and as such is associated with the development of peripheral polyarthritis rather than spondylitis. Further investigation of possible HLA-Cw*0602 linked genes in PsA is warranted.

Adult↗
PubMed2001

Why plants grow poorly on very acid soils: are ecologists missing the obvious?

Factors associated with soil acidity are considered to be limiting for plants in many parts of the world. This work was undertaken to investigate the role of the toxicity of hydrogen (H(+)) which seems to have been underconsidered by ecologists as an explanation of the reduced plant growth observed in very acid soils. Racial differences are reported in plant growth response to increasing acidity in the grass Holcus lanatus L. (Yorkshire-fog) and the tree Betula pendula Roth (Silver Birch). Soils and seeds were collected from four Scottish sites which covered a range of soils from acid (organic and mineral) to more base-rich. The sites and their pH (1:2.5 fresh soil:0.01 M CaCl(2)) were: Flanders Moss (FM), pH 3.2+/-0.03; Kippenrait Glen (KP), pH 4.8+/- 0.05; Kinloch Rannoch (KR), pH 6.1+/-0.16; and Sheriffmuir (SMM), pH 4.3+/-0.11. The growth rates of two races of H. lanatus, FM and KP, and three races of B. pendula (SMM, KP and KR) were measured in nutrient solution cultures at pH 2.0 (H. lanatus only), 3.0, 4.0, 5.0, and 5.6. Results showed races from acid organic soils (FM) were H(+)-tolerant while those from acid mineral soils (SMM) were Al(3+)-tolerant but not necessarily H(+)-tolerant. These results confirmed that populations were separately adapted to H(+) or Al(3+) toxicity and this was dependent upon the soil characteristics at their site of collection. The fact of plant adaptation to H(+) toxicity supports the view that this is an important factor in very acid soils.

Acids↗
PubMed2000

Dirigent-mediated podophyllotoxin biosynthesis in Linum flavum and Podophyllum peltatum.

Given the importance of the antitumor/antiviral lignans, podophyllotoxin and 5-methoxypodophyllotoxin, as biotechnological targets, their biosynthetic pathways were investigated in Podophyllum peltatum and Linum flavum. Entry into their pathways was established to occur via dirigent mediated coupling of E-coniferyl alcohol to afford (+)-pinoresinol; the encoding gene was cloned and the recombinant protein subsequently obtained. Radiolabeled substrate studies using partially purified enzyme preparations next revealed (+)-pinoresinol was enantiospecifically converted sequentially into (+)-lariciresinol and (-)-secoisolariciresinol via the action of an NADPH-dependent bifunctional pinoresinol/lariciresinol reductase. The resulting (-)-secoisolariciresinol was enantiospecifically dehydrogenated into (-)-matairesinol, as evidenced through the conversion of both radio- and stable isotopically labeled secoisolariciresinol into matairesinol, this being catalyzed by the NAD-dependent secoisolariciresinol dehydrogenase. (-)-Matairesinol was further hydroxylated to afford 7'-hydroxymatairesinol, this being efficiently metabolized into 5-methoxypodophyllotoxin. Thus much of the overall biosynthetic pathway to podophyllotoxin has been established, that is, from the dirigent mediated coupling of E-coniferyl alcohol to the subsequent conversions leading to 7'-hydroxymatairesinol.

Amino Acid Sequence↗
PubMed2000

Effects of aluminium on the growth and mineral composition of Betula pendula Roth.

Aluminium (Al) is rhizotoxic and is often present in acidic soils at activities high enough to inhibit root elongation. The objectives of the present study were to assess the level of Al tolerance in different races of Betula pendula Roth (Silver Birch) and to investigate how growth and nutrient acquisition were affected by Al. A solution culture technique was employed which simulated natural soil solutions. Aluminium at low concentrations (2 and 5 mg l(-1)), enhanced the growth of two races of B. pendula originating from soils poor in Al (FM and KP). In contrast, Al, at all concentrations tested, inhibited growth in an Al-sensitive race (KR) whose provenance was a calcareous soil. At concentrations >/=10 mg l(-1), Al reduced growth in FM and KP races, while growth increased with increasing Al (up to 25 mg l(-1)) in the Al-tolerant, SMM, race. Aluminium altered both root and leaf architecture. Low Al concentrations (<5 mg l(-1)) significantly increased leaf expansion, and high concentrations (>25 mg l(-1)) reduced leaf expansion. In the Al-sensitive race, KR, there was a loss of apical dominance, and both lateral and primary roots were stunted and swollen, with increasing Al concentrations. These results demonstrated pronounced racial differences in tolerance to Al by B. pendula that could be predicted from the soil environment of each race.

Aluminum↗
PubMed1999

Effects of nitrogen and phosphorus fertilization in a lowland evergreen rainforest.

A nutrient addition experiment was set up in August 1993 in a species-rich primary lowland dipterocarp forest in Barito Ulu, Central Kalimantan, Indonesia. The following treatments were applied: control, +N, +P and +NP. There were five blocks of four 50 m x 50 m plots with a separate treatment for each plot. Fine litterfall was measured on all the plots from 1 May 1994 for 12 months. Litterfall mass and phosphorus concentrations were significantly higher in all the fertilizer treatments compared with the controls. All trees (> or = 10 cm dbh) were measured in August 1993 and in August 1998, and there was no significant girth increment response to fertilization in dipterocarps or non-dipterocarps. Dipterocarps of the red meranti group showed a doubling of girth increment in the +NP treatment, however, the difference from the control fell short of significance.

Ecosystem↗
PubMed1997

Anti-cell surface endothelial antibodies in sera from cardiac and kidney transplant recipients: association with chronic rejection.

The aetiologies of accelerated or transplant-associated coronary artery disease (TxCAD) following cardiac transplantation and chronic rejection following renal transplantation remain ill-defined. Previous studies have used Western blotting to demonstrate an association between the formation of anti-endothelial (anti-EC) antibodies and TxCAD after heart transplantation. However, Western blotting favours detection of cytosolic proteins. The objectives of this study were to determine whether flow cytometry, a method which detects antigens on the cell surface, could be used to detect anti-EC antibodies and also whether the observations would extend to renal transplant patients with chronic rejection. Flow cytometry was used to look for antibodies reactive with the surface antigens of macrovascular and microvascular endothelial cell lines in sera from 44 cardiac and 35 renal transplant recipients before and after transplantation. In addition, sera from normals (n = 20), patients with nontransplant CAD (n = 50) and patients with unrelated diseases (n = 40) were investigated. Of 23 cardiac recipients who had developed TxCAD at one or two years post-transplant, 61% had IgM and 13% had IgG anti-EC antibodies post-transplantation. In contrast, in 21 cardiac recipients who had not developed TxCAD 14% had IgM and 14% IgG anti-EC antibodies. There was little evidence for the presence of anti-EC antibodies in cardiac recipients before transplantation. Of 26 renal transplant recipients whose transplants failed due to chronic rejection, 42% had IgG and 19% IgM anti-EC antibodies post-transplantation. Of nine renal recipients whose grafts were either functioning normally or who had acutely rejected, none had IgG or IgM anti-EC antibodies either pre- or post-transplantation. The anti-EC antibodies were not found in normals and were rare (less than 4%) in the other disease groups; they do not appear to be autoantibodies. In conclusion, these results suggest the FACS assay could be an informative and rapid test to provide more information on chronic rejection following cardiac and renal transplantation.

Adolescent↗
PubMed1994

A team approach to OR environmental issues.

At Munroe Regional Medical Center in Ocala, FL, an effective partnership between Materials Management and the Operating Room was begun by building consensus around a shared concern--minimizing the Operating Room's impact on the environment. To accurately evaluate cost-in-use issues, Materials Management and the OR needed a better understanding of each other's processes, procedures and decision-making criteria. Materials Management observed surgical procedures to understand product requirements, and OR personnel were given financial information on such matters as group purchasing and disposal costs. After considering all the data, the MM/OR team decided to continue using single-use polypropylene gowns rather than switch to reusable gowns. Success in this endeavor led the team to institute a disposable wrap recycling program. Lasting benefits of the collaboration include higher cost consciousness among clinicians, open communications, greater supplier accountability for cradle-to-grave cost estimates and team building.

Clothing↗
PubMed1990

Bowel perforation associated with intraperitoneal chromic phosphate instillation.

Intraperitoneal chromic phosphate is widely used as adjuvant therapy in the treatment of early-stage ovarian epithelial carcinoma. Delayed bowel injury is an infrequently observed complication of chromic phosphate administration. This report presents a case of colon perforation which occurred 4 months after treatment with intraperitoneal chromic phosphate for stage IB ovarian papillary serous cystadenocarcinoma.

Chromium↗
PubMed1988

Epidermal growth factor stimulates phosphatidylinositol turnover for ten hours in A431 cells without activation of protein kinase C.

Epidermal Growth Factor stimulated phosphatidylinositol turnover in A431 cells for up to ten hours. There was an increase in phosphatidylinositol, phosphatidylinositol-4-phosphate, phosphatidylinositol-4,5-bisphosphate and phosphatidic acid at all time points. The effects on the inositol phosphates were variable. Despite the activation of the phosphatidylinositol cycle, we were unable to demonstrate activation of protein kinase C.

Animals↗
PubMed1988

The reason for cardiac output reduction after aortic cross-clamping.

The hypothesis that a decrease in cardiac output during infrarenal aortic cross-clamping is related to a decrease in oxygen consumption in the perfused tissues (cross-clamp-adapted oxygen consumption) rather than to deterioration of myocardial performance has been tested. Twenty-two patients undergoing excision of an aortic abdominal aneurysm were randomly divided into two groups of equal number. During aortic cross-clamping, Group 1 patients received nitroglycerin infusion, 1 to 2 micrograms.kg-1.min-1, whereas Group 2 patients did not receive a nitroglycerin infusion. During aortic cross-clamping, cross-clamp-adapted body oxygen consumption decreased equally in both groups by 40 to 42 percent of baseline values, whereas cardiac output decreased by 17 percent in Group 2 but did not change significantly in Group 1. Mixed venous oxygen content increased significantly after induction of anesthesia and prior to aortic cross-clamping in both groups. During cross-clamping, the values of mixed venous oxygen content remained increased in Group 2 and increased further in Group 1. The data support our hypothesis since a decrease in cardiac output was not associated with an increase in filling pressures during aortic cross-clamping, but was instead associated with an increase in mixed venous oxygen content and a decrease in the arteriovenous oxygen content difference. Nitroglycerin infusion was associated with a further increase in mixed venous oxygen content during aortic cross-clamping and a decrease in the arteriovenous oxygen content difference, without a concomitant increase in oxygen utilization.

Aorta, Abdominal↗
PubMed1987

Total body oxygen supply-demand balance in burned patients under enflurane anesthesia.

The effects of enflurane anesthesia on the oxygen supply-demand balance have been studied in nine hypermetabolic-hyperdynamic burned patients undergoing debridement and skin-grafting procedures. Mean burn size was 55% of total body surface area. The patients were without cardiac, lung, hepatic, and kidney dysfunction and were not septic. Anesthesia was induced with sodium pentothal and maintained with enflurane and nitrous oxide in oxygen. Ventilation was controlled to maintain PaCO2 within normal limits. Crystalloid solutions and blood were administered to maintain adequate heart filling pressures. Serial measurements of cardiac output, arterial and mixed venous blood gases, and oxygen content were made before, during, and after anesthesia. Following induction of anesthesia and enflurane administration, cardiac output, oxygen delivery, and oxygen consumption decreased in a parallel fashion to approximately 60% of control. These variables did not change significantly throughout the procedure and returned to control values when enflurane was discontinued. Arteriovenous oxygen content difference did not increase and metabolic acidosis did not develop, suggesting that tissue perfusion remained adequate. Under anesthesia, oxygen consumption in burned patients was similar to that observed in normal subjects, indicating that enflurane blunts the hypermetabolic effects of thermal injury. It is concluded that in burned patients enflurane decreases metabolic rate and cardiac output, and maintains an adequate oxygen supply-demand balance.

Adolescent↗
PubMed1984

Hormonal and haemodynamic responses to upper abdominal surgery during isoflurane and balanced anaesthesia.

The purpose of the study was to compare the protective role of different anaesthetic techniques against surgical stress. Sixty patients undergoing elective laparotomy were randomly divided into six groups of ten patients each: Group I was given 0.65 MAC nitrous oxide (66 per cent inspired) and 0.65 MAC isoflurane (0.75 per cent end-expired); Group II was given 0.65 MAC nitrous oxide and 1-1.2 MAC isoflurane (1.2-1.4 per cent end-expired); Group III was given the same anaesthetic management as patients in Group I but with the addition of fentanyl (2 micrograms X kg-1) before the skin incision and 1/8 of the initial dose every 15 minutes during surgery; Group IV was treated as patients in Group I with an additional infusion of lidocaine (30 micrograms X kg-1 X min-1); Groups V and VI were given 0.65 MAC of nitrous oxide and fentanyl, 7.5 and 15 micrograms X kg-1, respectively, before skin incision with 1/8 of the initial dose every 15 minutes during the operation; diazepam, 5 mg IV each hour of surgery, was given to prevent intraoperative awareness. Cortisol concentration was determined by radioimmunoassay method and catecholamines were measured by high performance liquid gas chromatography in blood samples taken at different stages perioperatively. All patients had satisfactory haemodynamic courses of anaesthesia. Statistically significant increases in both epinephrine and norepinephrine concentrations were observed during the immediate postoperative period in Group I patients only. Haemodynamic stability was maintained despite a two- to three-fold increase in cortisol which occurred during the operation and immediate postoperative period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Blue fleck corneal iridescence: an occasional feature of Cogan's microcystic corneal dystrophy.

Flecks consisting of brilliant reflective blue dots and streaks were a prominent biomicroscopical feature in three patients with Cogan's microcystic corneal dystrophy. Two patients required epithelial debridement. We used the material obtained to investigate their histology and ultrastructure. A subepithelial accumulation of basement membrane-like material composed of ultrastructurally fine granules was deposited in alternating layers of compaction and rarefaction. The layers lie mostly parallel to the anterior corneal surface, but in some places they are folded. Such foldings are possibly the sites of multilaminar reflection and constructive interference, giving rise to the blue iridescence.

Adult↗