Biomedical subjects

K James

Publications and source records attributed to K James.

At least 109 records · Page 6Linked to original sources

PubMed1994

A simple method for isolating alpha 2 macroglobulin-cytokine complexes.

There is the need for a simple, effective procedure for separating alpha 2 macroglobulin-cytokine complexes from free cytokine in order that the nature and possible immunological significance of cytokine-binding by alpha 2 macroglobulin (alpha 2-M) might be further investigated. This presentation describes a method which exploits the presence of zinc-binding sites on alpha 2-M which permit the isolation of complexes from other proteins by zinc-affinity chromatography. Furthermore the method may be used in either a column or batch format.

Chromatography, Affinity↗

PubMed1994

The effect of alpha 2 macroglobulin in commercial cytokine assays.

alpha 2 macroglobulin (alpha 2M), a 725 kDa plasma protein, has been reported to bind a range of cytokines. We have therefore investigated its effect on a number of commercial cytokine assays. The methylamine converted fast form of the molecule was found to reproducibly depress, by 26% or more, the standard curves obtained with certain commercial assays for IL-2 and for tumor necrosis factor alpha, and had a small inhibitory effect on some IL-4 assays. In contrast it slightly enhanced or had no effect on ELISAs for IL-1 beta and IL-6. The inhibition observed was directly proportional to the concentration of alpha 2 M used in the range 0.5-5 mg/ml. Studies in the IL-2 system also revealed that it was largely attributable to the fast form of alpha 2M. Preliminary evidence suggests that the effects observed may be dependent on the assay source. These findings may be relevant to the assay of biological fluids in which alpha 2 M is present.

Artifacts↗

PubMed1994

Inhibition of thermolysin and neutral endopeptidase 24.11 by a novel glutaramide derivative: X-ray structure determination of the thermolysin-inhibitor complex.

Determination of the X-ray structure of thermolysin-inhibitor complexes has proven useful in aiding our understanding of the mode of binding of inhibitors of related, physiologically important, mammalian zinc peptidases including neutral endopeptidase EC 3.4.24.11 and angiotensin-converting enzyme. Here we describe the mode of binding to crystalline thermolysin of N-[1-(2(R,S)-carboxy-4-phenylbutyl)-cyclopentylcarbonyl]-(S) -tryptophan (CCT). CCT is an analogue of both candoxatrilat, a potent inhibitor of neutral endopeptidase 24.11, and of the 5-indanyl ester prodrug candoxatril, which is under clinical evaluation as a potential therapy for congestive heart failure. CCT differs from the previously studied N-carboxyalkyl dipeptide CLT [N-(S)-(1-carboxy-3-phenylpropyl)-(S)-leucyl-(S)-tryptophan] in several important respects. It has a highly constrained gem-cyclopentyl P1' substituent and lacks the characteristic imino nitrogen substituent of CLT. The structure determination shows that, notwithstanding the conformational influence of the gem-cyclopentyl substituent, CCT binds within the active site of thermolysin in a similar manner to CLT. Although the characteristic hydrogen bond between the imino nitrogen of CLT and thermolysin is absent in CCT, the affinities of the two inhibitors for the enzyme are virtually identical. These results illustrate the importance of considering not only those hydrogen bonds that are formed in an enzyme-ligand complex but also the other hydrogen bonds that may be lost due to desolvation of the enzyme and ligand on formation of the complex. In addition, the overall conformational demands placed upon a ligand in order to achieve receptor interaction may be critically important.

Amino Acid Sequence↗

PubMed1994

Ileal pouch-anal anastomosis: is preoperative anal manometry predictive of postoperative functional outcome?

PURPOSE: The aim of this study was to determine the value of preoperative anal manometry in predicting post-operative continence. METHODS: Anal manometry was performed in 73 consecutive patients before ileal pouch-anal anastomosis (IPAA) surgery (m1), before loop ileostomy closure (m2), and at a follow-up of one (m3) and two (m4) years. Mean and maximum resting and squeezing pressures were documented at each occasion. One year after surgery, pressures were correlated (r) with an incontinence score. RESULTS: A significant (P < 0.05) decrease in mean resting pressures was observed after IPAA (m1 = 66 mmHg; m2 = 42.8 mmHg), followed by a significant (P < 0.05) improvement of mean resting pressure after loop ileostomy closure (m3 = 53.8 mmHg; m4 = 54.7 mmHg). Mean squeezing pressures did not change (P > 0.05) at any time during the study (m1 = 114 mmHg; m2 = 102.9 mmHg; m3 = 103.4 mmHg; m4 = 95.8 mmHg). There was no correlation between preoperative mean resting pressure and postoperative (mI) incontinence score. CONCLUSION: Anal manometry showed a characteristic trend in internal anal sphincter injury after IPAA followed by recovery after ileostomy closure. However, it failed to prove helpful in the prediction of clinical outcome. Thus, although this study supports the continued use of manometry in a research setting, it challenges the value of routine manometry in a clinical context.

Anal Canal↗

PubMed1994

Recovery of anal sphincter function after the ileoanal reservoir procedure in patients over the age of fifty.

PURPOSE: This study was undertaken to postoperatively assess the progression of anal sphincter function and clinical outcome in patients > or = 50 years old (Group I) compared with those < 50 years old (Group II). METHODS: Clinical data were assessed after ileostomy closure by a questionnaire. These data were compiled to obtain an incontinence score, which ranged from 0 (perfect continence) to 20 (total incontinence). Anorectal manometry was performed preoperatively (MN1) and postoperatively, before (MN2) and after (MN3) ileostomy closure. Wilcoxon and paired t-test were used to compare the clinical and functional results, respectively. RESULTS: Group I consisted of 22 patients (mean age, 56 years) and Group II, 50 patients (mean age, 32 years). No differences were found relative to either preoperative pressures or clinical outcome. However, both the mean and high resting pressures were significantly lower in Group I at the MN2 examination. CONCLUSION: The effect on anal sphincters of ileoanal reservoir in patients over the age of 50 years is similar to that noted in younger patients. Transient impairment of internal anal sphincter function observed after ileoanal reservoir is more severe in older patients (P = 0.01). However, as in younger patients, it does completely recover after ileostomy closure.

Adenomatous Polyposis Coli↗

PubMed1994

Optimization of sphincter function after the ileoanal reservoir procedure. A prospective, randomized trial.

PURPOSE: Impairment of sphincter function in patients who undergo ileoanal reservoir is usually most severe immediately after ileostomy closure. Therefore, a prospective, randomized trial was undertaken to assess the potential value of preileostomy closure sphincter-strengthening exercises to improve early functional outcome. METHODS: Patients were randomized either to a control group (Group 1) or to undergo a five-week pelvic floor exercise program (Group 2). An incontinence score from 0 to 20 was used to clinically assess the functional results. Anorectal manometric assessment included: high-pressure zone length, mean resting pressure, highest resting pressure, mean squeezing pressure, and highest squeezing pressure. The paired t-test was used to compare the functional results preoperatively and at the time of ileostomy closure. This time corresponded to the conclusion of the exercise program or the equivalent time period for the control group. RESULTS: Twenty-six patients who underwent double-stapled ileoanal reservoir between July 1991 and June 1992 were studied. They included 16 males and 10 females with a mean age of 38 (range, 17-69) years. When both evaluations were compared, the mean incontinence score decreased from 0.2 to 2.8 (delta = 2.6) in Group 1 and from 0.2 to 2.0 (delta = 1.8) in Group 2 (P = 0.07). None of the changes between the preoperative and postoperative clinical and physiologic evaluations were statistically significant (P > 0.05). CONCLUSION: Sphincter-strengthening exercises before ileostomy closure did not minimize the transient impairment of functional results.

Adolescent↗

PubMed1994

The immunosuppressive contribution of prostaglandin components of human semen and their ability to elevate cyclic adenosine monophosphate levels in peripheral blood mononuclear cells.

We have compared the ability of fractions from seminal plasma to suppress lymphocyte proliferation and examined the effects of these fractions in raising intracellular cyclic adenosine monophosphate (cAMP) in the same preparations of peripheral blood mononuclear cells. Human seminal plasma is very effective at raising cAMP but seminal plasma stripped by C-18 reverse phase columns is inactive. Both prostaglandin E (PGE) and 19-hydroxy PGE contribute to the elevation of cAMP and a combination of these two prostaglandins is as effective as whole seminal plasma in raising cAMP but not as effective in inhibiting lymphoproliferation. These results suggest that human seminal plasma prostaglandins act through the EP2 receptor to inhibit T cell and NK cell function and thus attenuate both the cellular and humoral actions of the female's immune system.

Cyclic AMP↗

PubMed1994

Autocrine regulation of ICAM-1 expression on bladder cancer cell lines: evidence for the role of IL-1 alpha.

We have studied the autocrine regulation of essential expression of the intercellular adhesion molecule-1 (ICAM-1) on 8 transitional cell carcinoma (TCC) cell lines (histopathological grades 1-3). The constitutive expression of ICAM-1 was regulated by soluble factors in an autocrine fashion. These factors were produced by all cell lines, with the exception of the MGH-U1 cell line. The effects observed could be largely attributed to IL-1 alpha. However, the residual ICAM-1 inducing activity (up to 30% of ICAM-1 induction) could not be associated with any known ICAM-1 inducers (IFN gamma, TNF alpha, TNF beta, IL-1 alpha, IL-1 beta, IL-4, retinoic acid, LPS). In contrast to recombinant derived cytokines, the IL-1 alpha present in tissue culture supernatant was only able to induce ICAM-1 on high-grade tumours and not low-grade cells. This discriminative effect is similar to that noted following in vitro culture of tumour cells with bacillus Calmette-Guerin organisms. Whether the production of soluble factors (e.g., IL-1 alpha) by TCC cell lines plays an essential autocrine role for bladder tumours and/or affects the interaction with cells of the immune system needs to be investigated further.

Antigens, CD↗

PubMed1994

Expression of a common secretory granule specific protein as a marker for the extracellular organelles (prostasomes) in human semen.

OBJECTIVE: To further characterize prostasomes, trilamellar to multilamellar vesicles that are thought to originate from acinar cells of the human prostate and present in appreciable amounts in normal human semen. Purified prostasomes were shown to have immunosuppressive activity in vitro as measured by inhibition of mitogen-induced lymphocyte proliferation and inhibition of superoxide generation by neutrophils. A granule membrane protein, called granulophysin, has recently been identified in the membranes of platelet dense granules. Antibodies that recognize granulophysin also stain granules in different cell types including leukocytes, melanocytes, neurones, endothelial cells, and epithelial cells. DESIGN: The presence of epitopes recognized by antigranulophysin monoclonal antibody in prostasomes was investigated using indirect immunofluorescence and subsequent cytofluorimetric analysis. The protein was also analyzed by Western blotting. Reactivity of antigranulophysin antibody with the prostate tissue was studied by immunoperoxidase staining. RESULTS: A majority of prostasome particles specifically reacted with antigranulophysin antibody. In lysates prepared from prostasomes, a broad band of 32 to 37 kd was detected by Western blotting. CONCLUSION: This report defines granulophysin as a constituent membrane molecule of prostasomes that may serve as a useful marker in elucidation of prostasome function.

Antigens, CD↗

PubMed1994

A dosing scheme for carboplatin in adult cancer patients based upon pre-infusion renal function and platelet count.

The most important risk factors for the development of carboplatin-induced thrombocytopenia are total dose, glomerular filtration rate (GFR) and pre-infusion platelet count (P0). Pharmacokinetic and toxicity data from 23 patients with ovarian or testicular cancer were combined with published values from four other centers and the relationships between plasma clearance of ultrafilterable platinum and GFR, and between percentage reduction in platelet count and area under the plasma platinum curve were determined. The scatter in the data was estimated and used in a Monte-Carlo computer simulation to derive the following five-level dosing scheme. [table: see text] The scheme is based on 5% of patients incurring grade IV thrombocytopenia. Using this scheme, the majority of patients with ovarian or testicular cancer receiving carboplatin will be given an initial dose of 900 mg.

Adenocarcinoma↗

PubMed1994

Dexterity testing as a predictor of oral care ability.

OBJECTIVE: To examine a spectrum of elderly people to determine if hand function/dexterity measures can predict oral care ability. DESIGN: A series of dental, hand function, and dexterity measures were assessed by blinded examiners. Plaque scores were used as the criterion standard to assess plaque removal ability. PATIENTS: A convenience sample of 52, predominately male, elderly patients were recruited from the patient population of the Portland Veteran Affairs Medical Center and a community nursing home. Entry into the study required that the patient be able to give consent, be age 65 or older, have a minimum of six contiguous teeth or a minimum of 12 teeth total, be medically stable, have grossly adequate vision, and be able to hear and understand spoken instructions. OUTCOME MEASURES: The primary outcome measure was plaque score, as defined by the Turesky modification of the Quigley-Hein index. This was related to four dexterity tests (Jebsen-Taylor Hand Function test, Nine-hole Peg test, Box and Block test, Toothbrushing Ability test), a grip strength measure, and a cognitive measure (Allen Cognitive Level Test). RESULTS: Oral hygiene was significantly impaired among institutionalized elderly compared with outpatient elderly (P < 0.001), as was dexterity (P < 0.001). All dexterity tests correlated significantly with plaque score (Spearman rho: 0.49-0.77; P < 0.000). Forward stepwise regression analysis identified the Toothbrushing Ability Test (P < 0.0001) and the time spent brushing (P = 0.007) as the most significant predictors of plaque score. CONCLUSIONS: Results suggest oral hygiene ability is decreased among long term care residents, that dexterity tests can help identify patients unable to perform adequate oral self-care, and that these tests could be used to estimate brushing ability among elderly compromised patients.

Aged↗

PubMed1994

Induction of ICAM 1 expression on bladder tumours by BCG immunotherapy.

AIMS: To determine the expression of intercellular adhesion molecule 1 and 2 (ICAM 1 and 2) in transitional cell carcinoma cells before and after immunotherapy with Calmette-Guérin bacillus (BCG). METHODS: Frozen sections from 22 untreated bladder carcinomas were immunohistochemically examined with monoclonal antibodies to ICAM 1 and 2. Urinary cytospin slides were made for six patients for each of the six clinical instillations which constitute a therapeutic course. These slides were also stained for ICAM 1 and for leucocyte function associated antigen 1 (LFA 1). RESULTS: Bladder cancer cells did not essentially express either ICAM 1 or 2, but cells in the stromal areas surrounding tumour expressed both these antigens. After repeated instillations of BCG organisms ICAM 1 positive normal and neoplastic epithelial cells were observed in the urine. Cells obtained from the first three instillations expressed lower densities of ICAM 1 than those from the later instillations. Many neutrophils expressing LFA-1 and some lymphocytes were also noted in the cytospin slides and some of these were conjugated to tumour cells expressing ICAM 1. Six months after treatment a single maintenance dose of BCG induced ICAM 1 expression. CONCLUSION: Untreated superficial bladder carcinoma cells do not express ICAM 1 or 2, but these important immunological molecules were expressed in the stromal areas of tissue. Importantly, neoplastic cells in the urine expressed ICAM 1 after immunotherapy. This molecule can render bladder tumour cells vulnerable to non-antigen specific cytotoxicity mediated by activated lymphocytes.

Antigens, CD↗

PubMed1994

A follow-up of remanded mentally ill offenders given court hospital orders.

A follow up study of 101 men who were remanded to Brixton prison and who were given hospital orders by courts is reported. In 93% of cases the hospitals who responded to our enquiries reported that the admission had been appropriate. Only 5 (11%) of the 46 men who had been discharged from hospital had absconded or discharged themselves without medical approval. The process of referral and admission to hospital resulted in these men having to spend, on average, between two and three times longer in custody when compared to men charged with similar offences. It is generally recognized that the acutely ill should not be imprisoned, and encouragement has been given to the diversion of such people from the Criminal Justice System. However, London presents particular problems in this respect and it is argued that, since such problems will always be present, there is a need for special psychiatric facilities to be opened in order to serve the needs of the Capital.

Adult↗

PubMed1994

Psychotic men remanded in custody to Brixton Prison.

All referrals to medical officers in Brixton Prison over a five-month period in 1989 were examined. This paper reports the progress through this remand prison of those men who were considered to be suffering from a major psychiatric disorder. Many men had been charged with relatively minor offences. The net effect of medical intervention was to delay release from custody. Because of the administrative delays inherent in the system of medical referral and hospital admission under section 37 of the Mental Health Act 1983, it was those prisoners who were most ill who tended to remain in prison for the longest periods. Judged in terms of its efficiency to ensure speedy treatment for mentally ill remanded offenders, the present system is regarded as cumbersome and extremely inefficient. It is suggested that greater use should be made of section 48 of the 1993 Act to divert mentally ill, remanded offenders from prison.

Adolescent↗

PubMed1994

Control of leucocyte function-associated antigen-1-dependent cellular conjugation by divalent cations.

The control of integrin activation is fundamental to an understanding of the integrin-dependent cellular adhesion thought to be important for a plethora of basic cellular functions. Using a cell-cell conjugation assay the role of divalent cations in leucocyte function-associated antigen-1 (LFA-1)-dependent cellular adhesion was further investigated. The conjugation of interleukin-2 (IL-2)-activated lymphocytes to tumour cells was found to be energy dependent and required the presence of various divalent cations, removal of which decreased the level of conjugation. Increased concentrations of calcium, magnesium and manganese ions resulted in a corresponding increase in levels of conjugation. This increase in conjugation was LFA-1 dependent. Interestingly, when calcium ions were first removed from LFA-1, treatment of lymphocytes with magnesium and manganese ions gave significantly higher levels of conjugation than in the presence of calcium. Using a simple displacement study, calcium ions were shown to displace magnesium ions resulting in decreased conjugation. However, calcium ions were unable to displace manganese ions for binding to LFA-1. That manganese was exerting its effect via an LFA-1-dependent mechanism was confirmed using monoclonal antibodies to CD11a which negated the increased conjugation frequency due to manganese.

Antibodies↗

PubMed1993

Expression and shedding of ICAM-1 in bladder cancer and its immunotherapy.

Intercellular adhesion molecule-1 (ICAM-1) is one of 3 major ligands for the beta 2 integrin leucocyte function-associated antigen-1 (LFA-1). Several reports have emerged describing soluble forms of ICAM-1 in association with normal and pathological states (e.g., malignancy). In this study we have identified the secretion of soluble ICAM-1 in tissue culture supernatants from bladder tumour monolayers and in the urine of patients receiving intravesical BCG immunotherapy for superficial bladder cancer. In vitro, small amounts of sICAM-1 were detected in the tissue culture supernatants of bladder cancer cells, known to constitutively express ICAM-1. Following stimulation with interferon gamma, the levels of sICAM-1 increased inversely to the levels of cell surface ICAM-1, suggesting sheeding. Induction and augmentation of cell surface ICAM-1 required de novo mRNA and protein synthesis. However, treatment with cycloheximide, after stimulation with IFN-gamma, resulted in increased levels of membrane associated ICAM-1. Correspondingly, the level of sICAM-1 in the supernatant was low in comparison with controls, suggesting that cycloheximide acted via stabilization of membrane ICAM-1 or via prevention of some enzymatic cleavage event. In vivo, sICAM-1 can be detected at high levels in patients' urine following immunotherapy of bladder cancer with intravesically administered BCG organisms. Production of sICAM-1 is transient and occurs only in the first 12 hr following installation. Furthermore, production of sICAM-1 is heterogeneous as some patients fail to produce any at all. If the source of sICAM-1 is the bladder tumour per se, then its detection in urine could indicate a response of the tumour to immunotherapy and indeed may prove a useful indicator of clinical response.

BCG Vaccine↗

PubMed1993

Pitfalls in the use of ELISA to screen for monoclonal antibodies raised against small peptides.

Small peptides are often conjugated to large carrier proteins such as thyroglobulin to increase their immunogenicity. Antibodies are raised against peptide, thyroglobulin and contaminants, such as immunoglobulins or BSA in the thyroglobulin preparation, but anti-contaminant antibodies will not be revealed if immune serum is diluted in buffer containing immunoglobulin-contaminated BSA. This may lead to the development of an inappropriate hybridoma-screening assay which detects more anti-contaminant than anti-peptide antibodies if ELISA plates are coated with a capture antibody or blocked with BSA. Dilution of culture supernatants in buffer containing BSA and Tween 20 minimises the risk of false positive results and makes plate-blocking unnecessary. The high affinity peptide-specific antibodies in immune serum, which are more readily detected than lower affinity monoclonal antibodies, may result in an inadequately sensitive hybridoma-screening ELISA.

Animals↗

PubMed1993

Characterization of symptomatic and asymptomatic carotid plaques using high-resolution real-time ultrasonography.

High-resolution ultrasonography was used to classify carotid plaques into five different types in 72 patients with symptoms and in 49 without, and with stenosis of the origin of the internal carotid artery > 70 per cent. There were 72 plaques in the symptomatic group and 75 in the asymptomatic group. Type 1 plaques were uniformly echolucent, type 2 predominantly echolucent, type 3 predominantly echogenic, type 4 uniformly echogenic and type 5 consisted of plaques that could not be classified owing to heavy calcification and acoustic shadows. Type 1 plaque was found in 90 per cent of patients with symptoms and in 10 per cent of those without, type 2 plaque was found in 53 and 47 per cent, type 3 in 34 and 66 per cent, and type 4 in 5 and 95 per cent, respectively. The preponderance of echolucent plaques in symptomatic patients with stenosis > 70 per cent supports the hypothesis that this type of plaque is unstable and tends to embolize. In contrast, in patients without symptoms there is preponderance of echogenic plaques.

Arteriosclerosis↗