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Biomedical subjects

J J Wood

Publications and source records attributed to J J Wood.

At least 19 recordsLinked to original sources
PubMed2005

A prospective study of cutaneous nerve injury following long saphenous vein surgery.

OBJECTIVES: The aim of this study was to identify the incidence and distribution of nerve damage in patients undergoing primary venous surgery. METHODS: Patients undergoing primary great saphenous vein surgery between February and November 2003 were enrolled. In all cases the great saphenous vein was 'flush' ligated at the sapheno-femoral junction and stripped to the knee by inversion without using a stripper head; multiple phlebectomies were performed using an Oesch hook. A vascular nurse followed up patients 6 weeks post-operatively. Those reporting altered sensation and/or pain were examined by a doctor to provide an objective assessment of any neurological damage. These patients were again followed up by telephone at 6 and 12 months. RESULTS: Sixty-three limbs from 54 patients were enrolled. Numbness or paraesthesia was identified in 17 (27%) limbs at 6 week follow-up. 11 (17%) limbs were affected below the knee and 7 (11%) limbs were affected at the thigh or groin. One of the limbs was affected above and below the knee. Of these 17 limbs there was resolution in six limbs at 6 months and nine limbs at 12 months. Two patients with persistent nerve lesions regretted undergoing surgery. Patients undergoing bilateral surgery were more likely to report abnormal sensation (chi(2) test, p=0.006). There was no significant difference between the incidence of nerve injury for consultant, SpR or SHO as first operator (chi(2) test, p=0.9). CONCLUSION: This study demonstrates the frequency of nerve injury during primary great saphenous vein surgery. It will be useful for clinicians providing informed consent and may provide a benchmark for comparison with newer techniques.

Adult↗
PubMed2002

Diaphragm disease of the small bowel--a case report and literature review.

A 75-year-old man who had an emergency laparotomy for small bowel obstruction was found at operation to have multiple mid-ileal strictures. Histology of the resected specimen confirmed diaphragm disease of the bowel. The pathogenesis of this disease remains unclear but it is associated with long-term use of NSAID. Diagnosis is often difficult as many clinicians are unaware of this condition. The relevant literature has been reviewed.

Abdomen, Acute↗
PubMed1999

Synthetic pentasaccharides do not cause platelet activation by antiheparin-platelet factor 4 antibodies.

A synthetic selective inhibitor of factor Xa, the pentasaccharide SR90107A/Org31540 is in clinical development for the prophylaxis of postsurgical deep vein thrombosis. Another synthetic pentasaccharide with even more sustained inhibition of factor Xa, SanOrg34006, has also been developed. Both of these agents were tested in comparison to unfractionated heparin and a low molecular weight heparin (enoxaparin) for their relative platelet activation potential in heparin-induced thrombocytopenia assays. Sera from patients (n = 30) with heparin-induced thrombocytopenia were pooled and validated for heparin-dependent aggregation responses. Using heparin-platelet factor 4 Sepharose columns, antibodies to heparin-platelet factor 4 were purified from the same pool. The effects of heparin, enoxaparin, SR90107A/Org31540, and San-Org34006 were evaluated in a platelet aggregation assay using platelet donors (n = 10). At comparable concentrations, heparin and enoxaparin consistently produced platelet activation, whereas both pentasaccharides failed to produce a response at a concentration up to 100 micrograms/mL (approximately 50 microM). Similarly, in the 14C-serotonin release and flow cytometric assays, heparin and enoxaparin produced positive responses (n = 30), whereas the two pentasaccharides consistently failed to produce any effect. These observations suggest that the two pentasaccharides with highly selective anti-Xa activity are devoid of generating antiheparin-platelet factor 4 antibody, do not produce heparin-induced thrombocytopenic responses and may inhibit active heparin-induced thrombocytopenia antibody platelet activation.

Antibodies↗
PubMed1999

Laboratory diagnosis of heparin-induced thrombocytopenia.

The characteristics of the currently available platelet function assays (platelet aggregation, serotonin release, and flow cytometry) and enzyme-linked immunosorbent assays that quantitate antiheparin-platelet factor 4 antibody titers were studied using sera collected from clinically diagnosed heparin-induced thrombocytopenia patients, patients without heparin-induced thrombocytopenia, patients with platelet immune disorders other than heparin-induced thrombocytopenia, and normal individuals. The platelet aggregation assay was less sensitive than the serotonin release assay, which was less sensitive than the enzyme-linked immunosorbent assay (p < 0.001). Yet heparin-induced thrombocytopenia was identified by platelet aggregation assay in cases where the serotonin release assay and/or the enzyme-linked immunosorbent assay were negative. Patients with heparin-induced thrombocytopenia and thrombosis were more often positive than heparin-induced thrombocytopenia patients without thrombosis (p < 0.05). Positive platelet aggregation assay and serotonin release assay results were generally associated with a higher antibody titer; however, a minimum critical titer could not be identified. Over a 30-day period the percentage of positive responses did not change significantly even though clinical symptoms corrected in most heparin-induced thrombocytopenia patients. Multiple testing over several days enhanced the chance of detecting a positive, and combined results of the three assays further enhanced the positive response (p < 0.005). In patients without heparin-induced thrombocytopenia, false-positive results were obtained with the enzyme-linked immunosorbent assay. These data demonstrate that there is no direct correlation between the positive responses of these assays, that clinically positive patients can be missed by all assays, and the presence of antibody alone does not determine clinical heparin-induced thrombocytopenia. With these limitations, the combination of aggregation, serotonin release, and enzyme-linked immunosorbent assay testing with multiple samples offers the best chance of identifying a positive heparin-induced thrombocytopenia patient. Caution is advised for all assays as none is optimal.

Anticoagulants↗
PubMed1999

Laboratory tests for the diagnosis of heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is associated with high morbidity and mortality. Because the pathophysiology of this complex disorder has remained unclear, so has the development of supportive diagnostic laboratory assays. The currently available laboratory methods for HIT diagnosis include several platelet function assays: the platelet aggregation assay, platelet aggregation with simultaneous measurement of ATP release (lumi-aggregometry), the serotonin release assay, and flow cytometric assays. ELISA assays, which quantitate anti-heparin/platelet factor 4 antibody titers, have recently become available. Assay characteristics for these assays were studied using sera collected from clinically diagnosed HIT patients with and without thrombosis, normal individuals, various types of hospitalized patients without HIT, heparin or low molecular weight heparin-treated patients without HIT, and patients with platelet-immune disorders other than HIT. The results of our studies suggest that none of the assays can be considered a "gold standard" for the laboratory diagnosis of HIT as many false-negative and false-positive results were obtained. Furthermore, antibodies against the heparin/platelet factor 4 complex, as identified by the current ELISA tests, are not the sole cause of HIT since many patients lacking clinical symptoms associated with HIT exhibited high antibody titers following heparin treatment. An assay using flow cytometry, being developed for HIT testing, will be described. At this time, clinical impression remains important for the diagnosis of HIT.

Adult↗
PubMed1999

Vascular damage correlates between heparin-induced thrombocytopenia and the antiphospholipid syndrome.

Antibody-mediated disorders of heparin-induced thrombocytopenia and antiphospholipid antibody syndrome have remarkably similar clinical presentations, both of which can progressively result in severe vascular and thrombotic disorders. We hypothesized that the mechanism of platelet activation as occurs in heparin-induced thrombocytopenia may also occur in antiphospholipid antibody syndrome particularly at the vascular wall, that endothelial injury may be similar in heparin-induced thrombocytopenia and antiphospholipid antibody syndrome, and that these alterations may be caused by related antibodies. Antibody titers and vascular endothelial damage in patients with heparin-induced thrombocytopenia and antiphospholipid antibody syndrome were studied in plasma samples collected from normals (n = 17), heparin-induced thrombocytopenia patients (n = 15), antiphospholipid antibody syndrome patients (n = 30), and patients clinically diagnosed with antiphospholipid antibody syndrome and heparin-induced thrombocytopenia (n = 8). Diagnosis of heparin-induced thrombocytopenia was confirmed by 14C-serotonin release assay or positive antiheparin-platelet factor 4 antibody titer, and antiphospholipid antibody syndrome was confirmed by positive anti-beta 2-glycoprotein (GP) 1/cardiolipin (IgG or IgM) antibody titer. The antiheparin-platelet factor 4 antibody was not detected in any patient with antiphospholipid antibody syndrome. Patients with heparin-induced thrombocytopenia did not have elevated IgG anti-beta 2-GP1 titers, but three (20%) patients had low-positive IgM anti-beta 2-GP1 titers. The endothelial damage markers of soluble thrombomodulin, soluble P-selectin (p < 0.05 vs. normal), plasminogen activator inhibitor-1 and tissue factor were elevated in heparin-induced thrombocytopenia and antiphospholipid antibody syndrome patients. The soluble E-selectin was elevated only in the patients with both heparin-induced thrombocytopenia and antiphospholipid antibody syndrome (p < 0.05 vs. normal). Levels of soluble L-selectin and von Willebrand factor were not different from normals. The pathogenesis of heparin-induced thrombocytopenia and antiphospholipid antibody syndrome appears to be due to two distinct antibodies but associated with similar damage to the vascular endothelium in both diseases.

Antiphospholipid Syndrome↗
PubMed1999

Laboratory tests for heparin-induced thrombocytopenia: a multicenter study.

A multicenter clinical trial of the thrombin inhibitor argatroban (Novastan; Texas Biotechnology, Houston, TX; Smith-Kline Beecham Pharmaceuticals, Philadelphia, PA) was recently conducted in patients with heparin-induced thrombocytopenia (HIT) and HIT that had progressed to thrombosis (HITTS). In patients defined by the inclusion/exclusion criteria, the utility of three diagnostic HIT assays was investigated: the platelet aggregation assay, the serotonin release assay (SRA), and the enzyme-linked immunosorbent assay (ELISA) for the antibody to the heparin-platelet factor 4 (H-PF4) complex. Confirmation was made in 26%, 55%, and 64% of the patients, respectively (n = 199 patients; 512 to 606 samples; P < .001 platelet aggregation assay v SRA v ELISA). Patients who progressed to HITTS (n = 98) were more often confirmed than were HIT patients without associated thrombosis (n = 101) (P < .05). Confirmation by platelet aggregation assay and SRA results generally was associated with a higher antibody titer. However, a minimum critical titer could not be identified, because all patterns of positive and negative results by the platelet aggregation assay, SRA, and ELISA were observed, and clinically ill patients had a wide range of antibody titers. Over a 30-day period, the percentage of positive responses did not change. Although multiple testing over several days enhanced the chance of confirmation, this difference was not significant. Combined results of the three assays enhanced the positive response to 83% of the total population (P < .005). These data demonstrate that there is no direct correlation between the positive response of these assays, and that clinically positive HIT patients can be missed by all three assays. With these limitations, the combination of platelet aggregation assay, SRA, and ELISA testing with multiple samples offers the best chance of confirming a positive HIT patient. Caution is advised, however, in interpreting all assay results, as no assay is optimal.

Acute Disease↗
PubMed1995

Factors affecting the precision of TLD dose measurements using an automatic TLD reader.

An increase in the variability of TLD dose measurements prompted a study of the precision of dose measurements with a Rialto automatic TLD reader. It was found that readings with the same chip measured using two different trays could differ by as much as 7%. In order to overcome this problem it was necessary to ensure that individual chips were correctly identified. Marking the chips with a hard graphite pencil was found to be a satisfactory method of identifying them, which, although it reduced the light output by approximately 3%, had no effect on the reproducibility of readings. Using marked chips and an individual tray for each chip, the reproducibility of a reading was reduced to a typical value of 1%. A system of quality assurance based on these findings is described.

Automation↗
PubMed1991

Brachial plexopathy in breast carcinoma--an unsolved problem.

Brachial plexus involvement from carcinoma of the breast produces a severe disability which presents difficulties in diagnosis and treatment. Five patients who suffered this complication are described and the problems they present are discussed.

Adult↗
PubMed1988

Temporal correlation of impaired immune response after thermal injury with susceptibility to infection in a murine model.

Suppression of cellular immunity and increased susceptibility to sepsis frequently accompany thermal injury. However, a convincing association between the two has been difficult to establish in human beings. Therefore we chose to investigate the relationship of impaired cell-mediated immunity with susceptibility to sepsis in an animal model. We studied the response to phytohemagglutinin (PHA) and interleukin-2 (IL-2) production by splenocytes from mice subjected to a standard 25% scald burn and killed at intervals of 3, 5, 7, 10, 14, and 25 days after thermal injury. Burned mice were compared in all instances to sham-burn animals (i.e., animals that had been anesthetized and shaved but not burned). We also studied mortality after cecal ligation and puncture (CLP), as a septic challenge, in burned and control animals at the same postburn intervals. We found maximal suppression (50% to 55%) of the PHA response at 10 to 14 days after injury and maximum suppression (68%) of IL-2 production at 7 days. Both of these parameters returned to normal by postinjury day 28. Mortality after CLP increased gradually from control levels after thermal injury up to a maximum of 88% on postburn day 10 and also returned to control levels after 28 days after burn. Significant correlations were found between mortality after CLP in the postburn period and suppression of the PHA response, on the one hand, and the suppression of IL-2 production, on the other (r = 0.89 and 0.91, respectively; p less than 0.05). This result implies a causal relationship between impaired cell-mediated immunity and susceptibility to sepsis after burn injury.

Animals↗
PubMed1987

Suppression of interleukin 2 production in an animal model of thermal injury is related to prostaglandin synthesis.

We performed studies using an animal model of thermal injury to confirm the observed decrease in interleukin 2 (IL-2) production in burned patients and to explore the underlying mechanisms. Ten mice subjected to a 25% scald were compared with ten anesthetized littermates (controls) and six untreated mice (normal mice) 1, 3, 5, 7, 10, 14, and 21 days after burn. Production of IL-2 by splenocytes was stimulated by concanavalin A alone, or in the presence of the cyclooxygenase inhibitor indomethacin or flurbiprofen. The IL-2 content of the resulting supernatant was determined by the response of the IL-2-dependent cell line CTLL-2. The IL-2 production was significantly suppressed in the burned mice at three days (mean +/- SEM, 30.9% +/- 5.2%), five days (19% +/- 5.5%), seven days (41.6% +/- 6.4%), and 21 days (20% +/- 4.5%). Significant enhancement of IL-2 production by indomethacin was seen in the burned group (mean, 95%), but not in controls (mean, 23.8%) or normal mice (mean, 17.2%), and similar effects were seen with flurbiprofen. In separate experiments the effects of exogenous prostaglandin E2 on lymphocyte blastogenesis and IL-2 production were studied, and an increased susceptibility to the inhibitory effects of prostaglandin E2 was observed following thermal injury.

Animals↗
PubMed1987

Immature T lymphocytes after injury characterized by morphology and phenotypic markers.

Changes in the peripheral blood mononuclear cell (PBMC) population in patients following both thermal and nonthermal injury were defined by both morphological characteristics and surface phenotype with the monoclonal antibodies T6, OKT9, OKT10, and OKIa1, using a fluorescence activated flow cytometer with gating to separate small cells of the lymphocyte series from larger forms. Lymphocytes with surface antigens that bind T6, OKT9, and OKT10 are rarely found in the peripheral blood of adult patients, except in those with malignancies of the lymphoid system. In both burn and trauma patients the percentage of lymphocytes in the PBMC population after Ficoll-Hypaque separation was significantly reduced as compared with normal controls due to increases in the number of granulocytes, large granular lymphocytes (LGL), and monocytes, often present in immature forms. T6 cells were found in significantly greater numbers in both burn and nonthermal injury patients than in a control group using both small and wide gate settings on the fluorescence-activated flow cytometer. Significant increases in the number of T9+ cells also were observed in both groups for a prolonged period following injury. Significantly increased numbers of the T10+ and Ia1+ cells were detected in burn patients. The response to injury, therefore, involves the appearance in the peripheral blood of immature cells that may express T6, T9, T10, and Ia1 surface antigens. These cells may be present in quantities otherwise seen only in malignant disease.

Adolescent↗
PubMed1986

Abnormalities of antibody production after thermal injury. An association with reduced interleukin 2 production.

Antibody (Ab) production was studied in 25 burned patients who were immunized with 0.5 mg of tetanus toxoid adsorbed. Anti-tetanus toxoid (TT) Ab was measured by hemagglutination, radial immunodiffusion, and an enzyme-linked immunosorbent assay, and the results for the patients were compared with those for five similarly immunized healthy controls. As measured by hemagglutination, 12 (63%) of 19 patients had lower Ab responses than all five controls (P less than .05 by chi 2), and the median Ab response during the period of maximum response was significantly less than that in controls (8 vs 15.5 log2 maximum dilution; P = .014). After the initial response, serum Ab levels were not maintained in patients, in contrast to controls. This pattern was demonstrated by all three assays; enzyme-linked immunosorbent assay demonstrated that IgG anti-TT Ab was the major class of Ab produced. In nine patients interleukin 2 production by T lymphocytes was measured simultaneously; it was significantly depressed throughout the study except during the period from 36 to 45 days. The Ab response was also impaired in this patient group. Since maintained antibody production in response to TT is known to be T-cell dependent, these results suggest that inadequate interleukin 2 production leading to reduced T-cell help may be responsible for the lack of a persistent Ab response in these burned patients.

Adolescent↗
PubMed1986

Surgical management of 'lymphangioma circumscriptum'.

The results of surgery in 29 patients with 'lymphangioma circumscriptum' have been reviewed 2-8 years after operation. They show that in regard to management there are two varieties: small lesions, less than 7 cm diameter, in favourable sites of the body, which are potentially curable; and large lesions, greater than 7 cm diameter on the skin with an even larger area of subcutaneous cysts, in which complete excision of all the skin and subcutaneous vesicles would require skin grafting. Nine patients had small lesions excised. Seven have had no recurrence. Twenty patients had large lesions treated by a radical excision of all or as much of the cyst bearing subcutaneous tissues and skin as possible, but leaving enough skin to permit a primary suture, even though it meant leaving skin vesicles. The lesion was controlled and the cosmetic appearance improved in 16 patients. Subsequent regression of many of the vesicles not excised supports the aetiological hypothesis of the skin lesions proposed by Whimster.

Adolescent↗
PubMed1986

Suppression of natural killer-cell function in humans following thermal and traumatic injury.

Depressed cell-mediated and humoral immune functions have been reported to occur following severe thermal and traumatic injury. In this study we have questioned whether another immune function, natural killing (NK), is also disturbed in these injured patients. Twenty-two thermally injured patients with burns ranging from 5 to 75% of the total body surface area and 15 traumatically injured patients with injury severity scores ranging from 9 to 56 were followed postinjury and compared to 29 age-matched controls. NK activity was measured as the percentage cytotoxicity in chromium-51 release assays with K562 target cells. The more severely burned patients had significantly depressed NK activity for the 40-day period following injury that remained reduced for the duration of the study. Patients with lesser burns had reduced NK-cell function for the initial 10-day period postburn that returned slowly to the normal range. Traumatically injured patients had depressed NK-cell function during the 3- to 6-day period postinjury. The percentage of cells bearing phenotypic markers for the groups in which NK cells are found was either normal or elevated in these patients. A correlation was found between NK activity and interleukin 2 generation by mononuclear cells from these patients. In order to investigate the mechanism of NK suppression in these patients, NK-cell function was studied following the infusion of cortisol, epinephrine, and glucagon into volunteer subjects in amounts known to reproduce serum levels seen following injury of moderate severity. NK-cell function was reduced an average of 66% following infusion, suggesting that the inhibition of NK-cell function seen in patients may be mediated by the stress response to injury.

Adolescent↗