Biomedical subjects

C M Schmidt

Publications and source records attributed to C M Schmidt.

At least 19 recordsLinked to original sources

PubMed2001

Measuring the local burden of disease. A study of years of life lost in sub-Saharan Africa.

BACKGROUND: An effective health policy necessitates a reliable characterization of the burden of disease (BOD) by cause. The Global Burden of Disease Study (GBDS) aims to deliver this information. For sub-Saharan Africa (SSA) in particular, the GBDS relies on extrapolations and expert guesses. Its results lack validation by locally measured epidemiological data. METHODS: This study presents locally measured BOD data for a health district in Burkina Faso and compares them to the results of the GBDS for SSA. As BOD indicator, standard years of life lost (age-weighted YLL, discounted with a discount rate of 3%) are used as proposed by the GBDS. To investigate the influence of different age and time preference weights on our results, the BOD pattern is again estimated using, first, YLL with no discounting and no age-weighting, and, second, mortality figures. RESULTS: Our data exhibit the same qualitative BOD pattern as the GBDS results regarding age and gender. We estimated that 53.9% of the BOD is carried by men, whereas the GBDS reported this share to be 53.2%. The ranking of diseases by BOD share, though, differs substantially. Malaria, diarrhoeal diseases and lower respiratory infections occupy the first three ranks in our study and in the GBDS, only differing in their respective order. Protein-energy malnutrition, bacterial meningitis and intestinal nematode infections occupy ranks 5, 6 and 7 in Nouna but ranks 15, 27 and 38 in the GBDS. The results are not sensitive to the different age and time preference weights used. Specifically, the choice of parameters matters less than the choice of indicator. CONCLUSIONS: Local health policy should rather be based on local BOD measurement instead of relying on extrapolations that might not represent the true BOD structure by cause.

Africa South of the Sahara↗

PubMed2001

Laparoscopic surgery for Crohn's disease: reasons for conversion.

OBJECTIVE: To examine factors influencing conversion from a laparoscopic to an open procedure in patients requiring surgery for Crohn's disease. SUMMARY BACKGROUND DATA: Laparoscopic management of patients with complications of Crohn's produces better outcomes than traditional open approaches, but it is difficult to determine before surgery who will be amenable to laparoscopic management. In this series, a laparoscopic approach was offered to virtually all patients to determine reasons for laparoscopic failure. METHODS: Data regarding patients who underwent attempted laparoscopic procedures for Crohn's (January 1993 to June 2000) were collected prospectively. The bowel was mobilized laparoscopically and extracorporeal anastomoses were performed. Conversion to open surgery was defined as creation of an incision of more than 5 cm. RESULTS: One hundred ten patients (age 37 +/- 1.1 years, 58% female) underwent 113 attempted laparoscopic interventions. Indications for surgery included obstruction (77%), failure of medical management (35%), fistula (27%), and perineal sepsis (4%). Sixty-eight procedures (60%) were completed laparoscopically. Procedures completed laparoscopically included ileocecectomy (n = 46), small bowel resection (n = 22), fecal diversion (n = 7), intestinal stricturoplasty (n = 7), resection of prior ileocolonic anastomosis (n = 5), segmental colectomy (n = 1), and lysis of adhesions (n = 1). Forty-five procedures (40%) were converted as a result of adhesions (n = 21), extent of inflammation or disease (n = 9), size of the inflammatory mass (n = 7), inability to dissect a fistula (n = 5), or inability to assess anatomy (n = 3). Factors associated with conversion were internal fistula as an indication for surgery, smoking, steroid administration, extracecal colonic disease, and preoperative malnutrition. In laparoscopic patients, mean times to passage of flatus and first bowel movement were 3.6 +/- 0.2 days and 4.4 +/- 0.2 days, respectively. Mean time to discharge was 6 +/- 0.2 days. CONCLUSIONS: Attempted laparoscopic management is safe and effective if there is an appropriate threshold for conversion to an open procedure. Conversion factors identified in this study largely reflect technical challenge and severity of disease. Patients taking steroids and those with known fistulas or colonic involvement threaten laparoscopic failure, but many of these patients can be managed laparoscopically and have better outcomes. By understanding the reasons for conversion, it is hoped that the chances of laparoscopic success can be improved by modifying standard preoperative medical management or using additional technological capabilities (e.g., robotics).

Adult↗

PubMed2001

A randomized trial of the long-term effects of digital ocular compression in the late postoperative period.

PURPOSE: To determine whether digital ocular compression is a viable technique to lower intraocular pressure in patients at least 3 months after trabeculectomy. PATIENTS AND METHODS: A 6-month prospective, randomized, controlled, single-masked trial of 29 patients who underwent a trabeculectomy at the Glaucoma Service of Wills Eye Hospital. Patients were assigned to two groups: ocular compression or cheekbone compression (control group). The ocular compression group performed compression to the operated eye three times a day in the pattern of 10 seconds of pressure, 5 seconds of rest, and 10 seconds of pressure. Pressure was applied with the index finger through the closed lid to the center of the cornea. Pressure was steady and firm, but not painful. No massaging was performed. The cheekbone compression group applied pressure to the zygomatic arch with an identical style and frequency. RESULTS: At 6 months, the change in mean intraocular pressure for the ocular compression group was 0.25 mm Hg compared with -0.44 mm Hg for the control group (P = 0.7). A few patients in both groups experienced large swings in intraocular pressure and mild to moderate discomfort. CONCLUSION: Ocular compression had little to no success in the long-term management of increased intraocular pressure in the late postoperative period in this study.

Aged↗

PubMed2001

Circulation of core collection monographs in an academic medical library.

Academic medical librarians responsible for monograph acquisition face a challenging task. From the plethora of medical monographs published each year, academic medical librarians must select those most useful to their patrons. Unfortunately, none of the selection tools available to medical librarians are specifically intended to assist academic librarians with medical monograph selection. The few short core collection lists that are available are intended for use in the small hospital or internal medicine department library. As these are the only selection tools available, however, many academic medical librarians spend considerable time reviewing these collection lists and place heavy emphasis on the acquisition of listed books. The study reported here was initiated to determine whether the circulation of listed books in an academic library justified the emphasis placed on the acquisition of these books. Circulation statistics for "listed" and "nonlisted" books in the hematology (WH) section of Indiana University School of Medicine's Ruth Lilly Medical Library were studied. The average circulation figures for listed books were nearly two times as high as the corresponding figures for the WH books in general. These data support the policies of those academic medical libraries that place a high priority on collection of listed books.

Book Selection↗

PubMed1999

Altered Gq/G11 guanine nucleotide regulatory protein expression in a rat model of hepatocellular carcinoma: role in mitogenesis.

Guanine nucleotide regulatory proteins (G-proteins) represent an important transmembrane pathway whereby extra-cellular signals are transduced to intracellular signaling pathways. The mitogen-activated protein kinase (MAPK) cascade has been identified as a key factor in transducing numerous mitogenic stimuli. MAPK activity is regulated via numerous receptor types, including those linked to Gq/G11-proteins, which regulate phospholipase-C activity. We hypothesized that alterations in a Gq/G11-PLC pathway may contribute to the enhanced cellular mitogenesis characteristic of hepatocellular carcinoma (HCC), possibly via a MAPK-dependent pathway. By using an in vivo model of HCC we investigated changes in Gq/G11-protein expression in tumorigenic tissue versus adjacent, non-neoplastic liver. In addition we addressed the role of Gq/G11-proteins in the regulation of MAPK-linked mitogenesis by using rat hepatic tumorigenic cells (H4IIE) and isolated hepatocytes in culture. Western blot analysis showed significant increases in Gqalpha and G11alpha expression in tumorigenic liver versus normal liver specimens, an effect that was augmented in cultured H4IIE cells versus isolated cultured hepatocytes. Furthermore, phosphoinositol specific phospholipase-C (PLC) activity was significantly increased in HCC versus normal liver. A specific PLC inhibitor (Et-18-OCH3) caused a dose-dependent decrease in serum stimulated DNA synthesis in both cultured H4IIE cells and isolated rat hepatocytes, the H4IIE cell line showing greater sensitivity to Et-18-OCH3. In addition, serum-stimulated MAPK activity was significantly enhanced in H4IIE versus cultured hepatocytes. Moreover, treatment with Et-18-OCH3 significantly attenuated serum stimulated MAPK activity in both cultured hepatocytes and H4IIE cells. Furthermore, U73122 (Gqalpha-PLC specific uncoupler) and GP2A (Gqalpha specific inhibitor) mirrored the effects of those observed for Et-18-OCH3 whereas PD98059 (specific MEK inhibitor) completely abolished serum-stimulated DNA synthesis in tumorigenic H4IIE cells. We conclude that HCC is associated with enhanced Gq/G11-PLC expression/activity as compared with normal liver. Furthermore, a PLC-linked MAPK cascade plays a significant role in the progression of the enhanced mitogenesis characteristic of HCC.

Animals↗

PubMed1999

Enhanced Gi-protein-mediated mitogenesis following chronic ethanol exposure in a rat model of experimental hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is associated with increased expression and function of inhibitory guanine nucleotide regulatory proteins (Gi-proteins). This study addresses the effects of chronic ethanol exposure on the expression and function of adenylyl cyclase (AC)-linked G-proteins (Gs and Gi) and growth in experimental HCC. G-protein expression and function was determined by immunoblot in the hepatic tumorigenic H4IIE cell line and isolated cultured hepatocytes in the absence or presence of ethanol (5-100 mmol/L). Chronic exposure (24 hours) to ethanol dose-dependently increased Gialpha1/2 expression in the H4IIE cell line, but not in cultured hepatocytes. Gsalpha-protein expression remained unchanged in both H4IIE cells and cultured hepatocytes following ethanol treatment. In addition, ethanol directly activated a Gi-protein, because pertussis toxin (PTx)-catalyzed, adenosine diphosphate (ADP)-dependent ribosylation of Gialpha substrates decreased following ethanol treatment. The increased functional activity of Gialpha1/2-protein expression was confirmed by demonstrating that ethanol dose-dependently inhibited basal and stimulated AC activity in H4IIE cells, while not significantly altering basal AC activity in isolated cultured hepatocytes. Furthermore, while ethanol had no significant effect on basal mitogenesis in H4IIE cells or hepatocytes, increased mitogenesis caused by direct Gialpha-protein stimulation (mastoparan M7; 10-5,000 nmol/L) was further enhanced in the presence of ethanol, an effect that was completely blocked following Gi-protein inhibition (PTx; 100 ng/mL). In contrast, activation of Gi-proteins using M7 failed to alter cellular mitogenesis in isolated cultured hepatocytes, whether in the absence or presence of ethanol. Finally, analysis of mitogen-activated protein kinase (MAPK) activity demonstrated that chronic ethanol treatment further enhanced Gi-protein-stimulated MAPK activity in hepatic tumorigenic cells. In conclusion, these data demonstrate that ethanol enhances cellular mitogenesis in experimental HCC as a result of, at least in part, a Gi-MAPK-dependent pathway. Furthermore, this effect may be caused by ethanol's direct up-regulation of the expression and activity of Gi-proteins in HCC.

Adenosine Diphosphate Ribose↗

PubMed1999

Reversal of optic disc cupping after glaucoma surgery analyzed with a scanning laser tomograph.

OBJECTIVE: To detect and quantitate changes in optic nerve morphology after glaucoma surgery using the Heidelberg Retina Tomograph (HRT, Heidelberg Instruments, Heidelberg, Germany). DESIGN: Nonconsecutive observational case series. PARTICIPANTS AND INTERVENTION: The authors prospectively enrolled 21 adult patients undergoing incisional glaucoma surgery for progressive glaucoma damage. Quantitative analysis of the optic nerve head by scanning laser tomography and automated perimetry were performed before and after glaucoma surgery. MAIN OUTCOME MEASURES: Changes in optic nerve parameters were subjected to linear regression analysis with respect to percent of postoperative reduction of intraocular pressure (IOP), as well as with respect to age, refraction, preoperative cup:disc ratio, and change in visual field parameters. RESULTS: Seventeen patients had pre- and postoperative images suitable for analysis. Mean IOP at the time of image acquisition before surgery was 30.5+/-12 mm Hg, and after surgery 11.8+/-5.2 mm Hg (mean follow-up, 26+/-7 weeks). Eleven of 13 (85%) patients having IOP reduction of greater than 40% showed improvement in optic disc parameters. All four patients with less than 25% reduction in IOP showed worsening of most parameters. Changes in optic disc parameters were highly correlated with percent IOP reduction and with age. The parameters in which change most strongly correlated with percent change of IOP were cup area, rim area, cup:disc ratio, and mean cup depth (each, P<0.005). The age of the patient correlated highly with change in maximum cup depth (P<0.005). Refraction and clinically determined cup:disc ratio correlated poorly with changes in measured optic disc parameters. Clinical improvement in visual fields was correlated with the degree of improvement of cup:disc ratio (P = 0.025). CONCLUSION: Most patients showing a 40% lowering of IOP after glaucoma surgery show improved optic nerve morphology as measured by the HRT. The amount of improvement correlated highly with the percent reduction of IOP.

Adult↗

PubMed1999

Long-term outcome of aqueous shunt surgery in ten patients with iridocorneal endothelial syndrome.

PURPOSE: To report the long-term outcome of ten patients with iridocorneal endothelial (ICE) syndrome who underwent aqueous shunt surgery for uncontrolled glaucoma. DESIGN: Noncomparative, retrospective case series. PARTICIPANTS: The authors reviewed charts of ten patients with ICE syndrome-related glaucoma who underwent aqueous shunt surgery at one institution between 1987 and 1996. MAIN OUTCOME MEASURES: Intraocular pressure (IOP), number of glaucoma medications, and further surgical interventions were measured. RESULTS: With a median follow-up of 55 months, four eyes had adequate IOP control (IOP <21 mm Hg) with one or two medications after the initial aqueous shunt surgery. An additional three eyes achieved adequate IOP control after one or more tube repositionings or revisions of the initial aqueous shunt. In this series, the aqueous shunt surgery most often failed because of blocking of the tube ostium by iris, ICE membrane, or membrane-induced tube migration. CONCLUSION: Aqueous shunt surgery appears to be an effective method for IOP lowering in some eyes with ICE syndrome-related glaucoma when medical treatment or conventional filtration surgeries fail, but additional glaucoma procedures and/or aqueous shunt revisions and tube repositionings are not uncommon.

Adult↗

PubMed1999

Characterization of spontaneous metastasis in an aggressive breast carcinoma model using flow cytometry.

Studies of metastasis can be accelerated and provide more mechanistic information using cell lines which reproducibly and aggressively metastasize, and which are accurately and easily detected in tissues at all stages of the metastatic process. Although reporter proteins such as green fluorescent protein (GFP) and beta-galactosidase have improved the tracking of tumor cells in vivo, their measurement has often been limited to visual observation and manual counting. In this study, we exploited the highly sensitive and objective quantitation provided by flow cytometry to characterize, in detail, the sequence of events associated with orthotopic metastasis in a highly aggressive mouse model. Following stable transfection of the MDA-MB-435 breast carcinoma cell line with GFP, we utilized an in vivo selection process to isolate a variant exhibiting increased primary tumor growth and metastasis. As few as one fluorescent tumor cell per 200,000 host cells could be accurately detected in dissociated tissues by flow cytometry, allowing us to demonstrate that metastatic cells migrate to the lungs of SCID mice very early after orthotopic implantation. Tumor burden in lungs increased in a smooth continuous manner, until death approximately eight weeks later. Levels of circulating tumor cells in blood were also detectable at an early timepoint, but remained relatively low throughout the course of secondary tumor development in the lungs. Surgical removal of the primary tumor at various times after inoculation significantly affected lung tumor burden, supporting the concept that circulating tumor cells in blood inefficiently initiate distal metastases. Furthermore, the continuing contribution to metastasis by the primary tumor was independent of tumor mass. The combined characteristics of enhanced orthotopic metastasis and quantitative detection in blood and tissues will make this a useful new model for the characterization of the multi-stage progression of cancer, and the preclinical evaluation of anti-neoplastic therapies.

Breast Neoplasms↗

PubMed1999

Inhibitory guanine nucleotide regulatory protein activation of mitogen-activated protein kinase in experimental hepatocellular carcinoma in vitro.

OBJECTIVE: Hepatocellular carcinoma (HCC) is associated with altered expression and function of inhibitory guanine nucleotide regulatory proteins (Gi-proteins). This study addresses the interaction between Gi-proteins and the extracellular regulated kinase (ERK) component of the mitogen activated protein kinase (MAPK) cascade in regulating mitogenesis in an experimental model of HCC. DESIGN: Pharmacological agents which selectively interact with specific target proteins involved in signal transduction through a Gi-MAPK pathway have recently become available. These agents in combination with scientific assays allow us to address the role of individual components of this cascade in the regulation of mitogenesis in HCC. METHODS: These studies were performed using rat hepatic tumorigenic cells (H4IIE) and isolated cultured hepatocytes in vitro in conjunction with pharmacological agents which interact with Gi-protein or MAPK components of intracellular signalling. RESULTS: Direct activation of Gi-proteins with mastoparan M7 (M7) significantly increased nuclear thymidine incorporation in hepatic tumorigenic H4IIE cells in a dose-dependent manner (10-1000 nM, n = 4, P < 0.05), an effect that was abolished by treatment with either pertussis toxin (PTx) or the selective mitogen-activated ERK-regulated kinase (MEK) inhibitor PD098059. In contrast, M7 inhibited nuclear thymidine incorporation in serum-stimulated isolated hepatocytes. ERK2 activity was then determined as the ability of immunoprecipitated ERK2 proteins to phosphorylate the ERK substrate myelin basic protein. These studies demonstrated a time- and dose-dependent increase in ERK2 activity in H4IIE cells following Gi-protein activation with M7, a maximal response being attained at 20 min. In contrast, M7 failed to significantly alter ERK2 activity in isolated cultured hepatocytes at any of the doses or time points assayed (10-5000 nM, 10-120 min). Gi-stimulated ERK activation was completely blocked in tumorigenic cells following treatment with PTx. CONCLUSIONS: These data demonstrate for the first time a Gi-linked MAPK cascade in experimental HCC, activation of which stimulates cellular mitogenesis.

Animals↗

PubMed1999

The role of cAMP-MAPK signalling in the regulation of human hepatocellular carcinoma growth in vitro.

OBJECTIVE: We have previously identified that primary human hepatocellular carcinoma (HCC) is associated with altered guanine nucleotide regulatory protein (G-protein) expression concomitant with decreased adenylyl cyclase (AC) and increased mitogen activated protein kinase (MAPK) activity in vivo. This study aims to address the potential link between Gs protein regulation of AC activity/ cyclic adenosine monophosphate (cAMP) production and the subsequent downstream regulation of MAPK activity and mitogenesis. DESIGN: Pharmacological agents which selectively interact with specific target proteins involved in signal transduction via the Gs-AC-cAMP-MAPK signalling pathway were employed in cultured human HCC cell lines in these studies. These agents allow us to address the role of individual components of these pathways in the regulation of mitogenesis in HCC. METHODS: These studies utilized three distinct human HCC cell lines (HepG2, Hep3B and SKHep) in the absence and presence of agents that alter AC-cAMP dependent signalling. De novo DNA synthesis was determined as a marker of altered cellular proliferation, and MAPK activity was determined as the ability to catalyse myelin basic protein (MBP) phosphorylation. RESULTS: 8-Bromo-cAMP (8-Br-cAMP; a cell-permeable cAMP analogue) and forskolin (AC activator) dose-dependently decreased thymidine incorporation in all three cell lines. In addition, serum-stimulated [3H] thymidine incorporation was significantly decreased in HepG2, Hep3B and SKHep cell lines following treatment with either 8-Br-cAMP or forskolin. By contrast, MDL12330A (MDL; irreversible AC inhibitor) enhanced thymidine incorporation in all three cell lines. Treatment with either 8-Br-cAMP or forskolin significantly decreased serum-stimulated MAPK activity. CONCLUSIONS: These data suggest that cAMP acts as an anti-mitogenic agent in these hepatic tumorigenic cell lines in vitro such that inhibition of AC activity promotes MAPK activity and cellular mitogenesis in HCC.

Carcinoma, Hepatocellular↗

PubMed1999

Filtration procedures supplemented with mitomycin C in the management of childhood glaucoma.

AIMS: To evaluate the outcome of filtering procedures supplemented with mitomycin C in children with glaucoma. METHODS: All patients aged 17 or younger with glaucoma who underwent filtering surgery supplemented with mitomycin C at a tertiary care centre (n = 21) during a 5 year interval (1992 and 1996) were included. One eye for each patient was entered into the analysis. The postoperative intraocular pressure (IOP), use of antiglaucoma medications, clinical stability of glaucoma, complications, and visual acuity were retrospectively evaluated. Kaplan-Meier survival curves were used to estimate the probability of success. RESULTS: At the time of surgery mean age was 5.7 (SD 5.0) years. The most common diagnoses were trabeculodysgenesis (n = 6) and aphakic glaucoma (n = 8). Mean IOP before surgery was 35.7 (10.5) mm Hg. Average length of follow up was 18.6 (14.7) months. The probability of having IOP less than 21 mm Hg with no antiglaucoma medications and with clinically stable glaucoma 1 year after surgery was 76.9% in phakic eyes (n = 13) and 0% in aphakic eyes (n = 8). A phakic patient with Sturge-Weber's syndrome had choroidal effusion after surgery that resolved spontaneously. In the aphakic group one patient had retinal detachment and another developed an encapsulated bleb. Visual acuity deteriorated in one patient. CONCLUSION: A guarded filtration procedure with mitomycin C is relatively successful in phakic children with glaucoma, but unsuccessful in aphakic ones.

Adolescent↗

PubMed1999

Pre-beta-HDL stimulates placental lactogen release from human trophoblast cells.

To examine whether pre-beta-high-density lipoprotein (HDL) may be involved in regulation of human placental lactogen (hPL) release, pre-beta-HDL was isolated from term pregnancy serum, and the effect of purified pre-beta-HDL on hPL release from trophoblast cells was examined after 1 h of exposure. Pre-beta-HDL stimulated a dose-dependent increase in hPL release with half-maximal stimulation at a dose of 300-400 microgram/ml, which is within the normal physiological range during pregnancy. Analysis of pre-beta-HDL and alpha-HDL in serum from pregnant women at different stages of gestation (determined by Western blot analysis) indicated that the pre-beta-HDL-to-alpha-HDL ratio increased linearly after the 10th week of gestation (r = 0.88, P < 0.001), reaching a maximum sixfold greater than that of nonpregnant women. The increase in serum pre-beta-HDL during pregnancy paralleled that of plasma hPL concentrations (r = 0.93, P < 0.001). Two-dimensional electrophoresis indicated that the increase in pre-beta-HDL was due primarily to an increase in pre-beta1-HDL and pre-beta2-HDL, two of the three forms of pre-beta-HDL present in blood. These results suggest a role for pre-beta-HDL in the regulation of hPL expression during pregnancy.

Cells, Cultured↗

PubMed1999

Autologous patch graft in tube shunt surgery.

PURPOSE: To evaluate an alternate method of covering the subconjunctival portion of the tube in aqueous shunt surgery. Evidence of tube erosion, graft-related infection, graft melting, or other associated intraocular complications were evaluated. METHODS: A retrospective study of 16 patients (17 eyes) who underwent tube shunt surgery at Wills Eye Hospital between July 1991 and October 1996 was conducted. An autologous either "free" or "rotating" scleral lamellar graft was created to cover the subconjunctival portion of the tube shunt. RESULTS: All patients were evaluated for at least 6 months, with a mean follow-up of 14.8 months (range 6-62 months). All eyes tolerated the autologous graft well, with no clinical evidence of tube erosion, or graft-related or intraocular complications. CONCLUSION: Autologous patch graft in tube shunt surgery appears--in selected cases--to be an effective, safe and inexpensive surgical alternative to allogenic graft materials. It also offers ease of availability, and eliminates the risk of transmitting infectious disease.

Adult↗

PubMed1998

Characteristics of cation binding to the I domains of LFA-1 and MAC-1. The LFA-1 I domain contains a Ca2+-binding site.

The crystal structures of the I domains of integrins MAC-1 (alphaM beta2; CD11b/CD18) and LFA-1 (alphaL beta2; CD11a/CD18) show that a single conserved cation-binding site is present in each protein. Purified recombinant I domains have intrinsic ligand binding activity, and in several systems this interaction has been demonstrated to be cation-dependent. It has been proposed that the I domain cation-binding site represents a general metal ion-dependent adhesion motif utilized for binding protein ligands. Here we show that the purified recombinant I domain of LFA-1 (alphaLI) binds cations, but with significantly different characteristics compared with the I domain of MAC-1 (alphaMI). Both alphaLI and alphaMI bind 54Mn2+ in a conformation-dependent manner, and in general, cations with charge and size characteristics similar to Mn2+ most effectively inhibit 54Mn2+ binding. Surprisingly, however, physiological levels of Ca2+ (1-2 mM) inhibited 54Mn2+ binding to purified alphaLI, but not to alphaMI. Using 45Ca2+ and 54Mn2+ in direct binding studies, the dissociation constants (KD) for the interactions between these cations and alphaLI were estimated to be 5-6 x 10(-5) and 1-2 x 10(-5) M, respectively. Together with the available structural information, the data suggest differential affinities for Mn2+ and Ca2+ binding to the single conserved site within alphaLI. Antagonism of LFA-1, but not MAC-1, -mediated cell adhesion by Ca2+ may be related to the Ca2+ binding activity of the LFA-1 I domain.

Binding Sites↗

PubMed1998

Preoperative terminal ileal and colonic resection histopathology predicts risk of pouchitis in patients after ileoanal pull-through procedure.

OBJECTIVE: This study seeks to compare the histopathology of preoperative terminal ileal and colonic resection specimens with pouch biopsies after the ileoanal pull-through (IAPT) procedure. SUMMARY BACKGROUND DATA: Pouchitis is the most frequent complication of transanal continent reservoirs in patients after IAPT. METHODS: The authors conducted 751 consecutive pouch biopsies on 73 patients with inflammatory bowel disease or familial adenomatous polyposis who underwent IAPT by a single surgeon over a 10-year period. In this preliminary report, a pathologist, in blinded fashion, has graded 468 of the IAPT pouch biopsies and 67 of the patients' preoperative terminal ileal and colonic resection histopathology to date. Colonic histopathology was graded by the extent and severity of disease, terminal ileal and pouch histopathology by active inflammation, chronic inflammation, lymphocyte aggregates, intraepithelial lymphocytes, eosinophils, and villous blunting. RESULTS: Extent of colonic disease (gross and microscopic) was a significant predictor of active inflammation in subsequent IAPT pouch biopsy specimens. Also, the gross extent of colonic disease exhibited a significant linear association with pouch inflammation. However, the severity of colonic disease was not significantly predictive of active inflammation in subsequent IAPT pouch biopsies. Terminal ileal active and chronic inflammation were significant predictors of subsequent IAPT pouch inflammation. Although lymphocyte aggregates and intraepithelial lymphocytes were not predictive, terminal ileum eosinophils and villous blunting were significant predictors of active inflammation in subsequent IAPT pouch biopsy specimens. CONCLUSIONS: Preoperative terminal ileal and colonic histopathology predicts active inflammation of pouches after IAPT. Patients who are preoperatively assessed to have extensive disease of the colon, ileal disease ("backwash ileitis"), or both appear to be at greater risk for the development of pouchitis after IAPT.

Adenomatous Polyposis Coli↗

PubMed1998

A study of antibody and T cell recognition of rhoptry-associated protein-1 (RAP-1) and RAP-2 recombinant proteins and peptides of Plasmodium falciparum in migrants and residents of the state of Rondonia, Brazil.

Humoral and cellular responses were examined among natives and migrants in an area of the Amazon region of Brazil. Rhoptry-associated protein-1 (RAP-1) and RAP-2 expressed in Escherichia coli expression systems, a peptide corresponding to the epitope bound by inhibitory anti-RAP-1 antibodies, and four other RAP-1 and RAP-2 synthetic peptides were used in these studies. Plasma from the native population had greater IgG reactivity to the N-terminal third of RAP-1 than the migrant population; both populations had low levels of IgM to this region of RAP-1. The IgG reactivity to RAP-2 and to the C-terminal third of RAP-1, as well as for all the peptides, including the peptide from the inhibitory domain, were low or absent in both populations. In contrast, there were a high number of subjects with an IgM response to the peptides. Cellular responses were measured by proliferation of peripheral blood mononuclear cells (PBMC) and, in some subjects, by reverse transcription-polymerase chain reaction for interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4, and IL-10. Proliferation of PBMC was low when stimulated by recombinant proteins, peptides, or parasite lysate. Both RAP-1 and RAP-2 stimulated cytokine production by donor T cells; IL-2, IL-4, and IFN-gamma RNA transcripts were observed in response to recombinant proteins and parasite lysate, but with no uniform trends. From the observed antibody responses, RAP-1 appears to be more immunogenic than RAP-2.

Adolescent↗

PubMed1997

Increased MAPK expression and activity in primary human hepatocellular carcinoma.

We investigated the expression and activity of mitogen-activated protein kinase (MAPK) in human hepatocellular carcinoma (HCC). MAPK expression was determined in five human tumors and five normal tissues (adjacent non-neoplastic liver) by Western blotting using specific antisera raised against four MAPK pathway intermediates: Erk-1, Erk-2 (extracellular-signal regulated kinases), Mek-1 and Mek-2 (mitogen activated protein kinase kinases). There was a significant increase in Erk-1, Erk-2, Mek-1 and Mek-2 expression in particulate and cytosolic fractions prepared from tumor specimens as compared with the adjacent normal control tissues. The functional activity of both membrane and cytosolic Erk-2, determined by phosphorylation of myelin basic protein (MBP), was significantly increased in tumor specimens as compared to normal (membrane: 321%+/-50%, p<0.05; and cytosol: 597%+/-233%, p<0.05 percent of normal tissue). These data demonstrate for the first time a significant increase in MAPK expression and functional activity in human HCC. Because of the important role that the MAPK pathway plays in cellular growth and differentiation, overexpression of MAPK may be of critical importance to the formation and maintenance of human hepatocellular carcinoma.

Blotting, Western↗