Activation of protein phosphatase 5 by limited proteolysis or the binding of polyunsaturated fatty acids to the TPR domain

In the urine of patients with bladder cancer, levels of the angiogenio peptide basic fibroblast growth factor (bFGF) may be elevated 100-fold. To date, levels of expression of bFGF in bladder tumor tissue have not been determined, nor has the cellular source of the urinary bFGF been identified. bFGF mRNA expression was quantified using RNase protection analysis in 32 primary bladder tumors and 8 normal bladder specimens. In addition, bFGF protein expression in the tumor cytosol was determined using a Quantikine ELISA, and bFGF protein expression was localized with immunohistochemistry. bFGF mRNA expression was absent in 28 of 32 (87%) bladder cancers despite detectable expression in 7 of 8 (87%) normal bladder specimens (P = 0.0001). In only one tumor was bFGF mRNA expression higher than in normal bladder tissue. Median bFGF protein expression was also higher in the normal bladder specimens than in the superficial tumors (3800 pg/g protein versus 1140 pg/g protein; P < 0.02), but there was no statistically significant difference between protein expression in normal bladder and invasive cancers (3800 pg/g versus 3600 pg/g). Median bFGF protein expression was higher in invasive cancers than in superficial tumors (P < 0.05). Intense bFGF immunoreactivity was seen in the basal lamina of normal transitional epithelium, in normal human detrusor muscle, and in vessels within tumors. Tumor cell immunoreactivity was rare and was usually weak. Only in the tumor which strongly overexpressed bFGF mRNA and protein was cytoplasmic staining detectable in the neoplastic cells. There are two mechanisms of bFGF-induced angiogenesis in bladder cancer. Rarely, neoplastic cells synthesize bFGF but more commonly bFGF is released by degradation of epithelial basement membranes and detrusor muscle, from where it can diffuse into the tumor microenvironment and bind to blood vessels. Mechanisms of extracellular matrix degradation may be important in bladder cancer angiogenesis and progression and as such are potential therapeutic targets.     

Self monitoring of blood glucose in blind diabetic patients

Blind diabetic patients face particular difficulties in blood glucose self monitoring (BGSM). We investigated the quality of BGSM in blind and severely visually impaired diabetic patients and assessed the effects of training in BGSM using a blood glucose meter with voice edition of values and a modified test strip holder for easier placement of blood samples on the strip (One Touch II talk (OT II)). Twenty-six insulin-treated diabetic patients (23 IDDM and 3 NIDDM) participated. At baseline the quality of BGSM was checked in 14 patients who already regularly performed BGSM without external help. Thereafter all 26 patients received an extensive instruction in BGSM for blind patients. At re-examination, after a mean period of 41 days, the quality of BGSM performed by the patients without assistance was checked in three different blood samples. Blood glucose was measured in the same sample by a routine laboratory method. At baseline the mean absolute difference between BGSM and the reference method was -0.3 mmol l(-1) (range; +/- SD) (-7.7-4.8; +/- 2.6 mmol l(-1)); 74% of BGSM measurements deviated by more than 10% from the reference values and 43% by more than 20%. At follow-up all 26 patients reported daily BGSM without external help. The mean absolute difference between BGSM and the reference method was -0.1 (-2.7-2.8; +/- 0.9 mmol l(-1)); 25% of BGSM measurements deviated by more than 10 % from the laboratory reference values and 5% by more than 20%. The results of this study suggest that a substantial number of blind diabetic patients do not perform BGSM on their own at all and in those who do the reliability of the results is poor. However, after extensive instruction, the majority of blind diabetic patients should be able to perform BGSM and to obtain reliable results.     

Initiation and propagation of blood coagulation at artificial surfaces studied in a capillary flow reactor

BACKGROUND: There is a potential for interaction between malaria and human immunodeficiency virus (HIV) infection. HIV infection might reduce immunity to malaria resulting in more frequent and severe infections; conversely malaria might enhance the progression of HIV infection to AIDS. In this paper we have reviewed some of the studies that have addressed this topic. METHODS: Studies identified by a MEDLINE search were systematically reviewed and the measures of association between the two infections were either abstracted or recalculated from the reported data. Inferences drawn from these studies and the biological plausibility of an interaction are discussed. RESULTS: The prevalence ratio (PR) of peripheral parasitaemia among HIV seropositive (HIVSP) individuals compared to HIV seronegative (HIVSN) individuals ranged from 0.72 to 0.94 in children and from 3.3 to 0.69 in adults. However, only one study showed a statistically significant difference between HIVSP and HIVSN groups (PR 3.3, 95% CI: 2.7-4.2). The rate ratio of non-severe malaria among HIVSP children compared to HIVSN children was 1.4 (95% CI: 0.99-2.0). Data from a trial of chemoprophylaxis during pregnancy suggested that placental malaria may predispose to perinatal transmission of HIV. Studies that have investigated the immune response to P. falciparum among HIVSP subjects have given variable results. CONCLUSION: There is no convincing evidence for an interaction between malaria and HIV with the possible exception of an interaction between placental malaria and HIV infection. Several studies, however, had potentials for bias and/or an inadequate sample size. There is a need for carefully designed studies to resolve whether mortality from severe malaria, in particular cerebral malaria, is increased in HIVSP subjects, whether malaria infection of the placenta increases the risk of vertical transmission of HIV, and whether malaria infection increases the progression of HIV infection to AIDS.     

Laser-Doppler scanning of local cerebral blood flow and reserve capacity and testing of motor and memory functions in a chronic 2-vessel occlusion model in rats

BACKGROUND AND PURPOSE: An animal model of incomplete forebrain ischemia resembling human hemodynamic insufficiency was established. The model allows examination of acute and chronic changes of local cerebral blood flow (lCBF) and reserve capacity in correlation with behavioral parameters. METHODS: Anesthetized male Wistar-Kyoto rats underwent bilateral carotid occlusion (BCO). Laser-Doppler scanning of lCBF at baseline conditions and after acetazolamide was done 30 minutes after BCO, motor and memory function tests were administered after 1 and 2 days, and both investigations were repeated after 1, 2, 4, and 6 weeks. A sham-operated and a control group without any vessel manipulation served as controls. RESULTS: lCBF dropped within 60 minutes after surgery by 62% (P<0.001) in 10 animals surviving BCO (BCOsurvival) and by 69% in 5 rats that died within 9 days (BCOlethal). Acetazolamide increased lCBF to 142.33% in controls, to 136.66% in sham-operated rats (both significant), and to 104.80% in BCOsurvival (not significant), and it decreased flow by 23.1% in BCOlethal rats (P<0.001). Baseline lCBF normalized within 4 weeks. Total motor function scores were significantly reduced from 9 points preoperatively to 5.80+/-0.65 in BCOlethal and 6.68+/-0.54 points in BCOsurvival rats 1 day after occlusion. Memory retention function remained impaired after BCO, as did the acetazolamide response, which correlated with motor score and was inversely related to maze exploration time. CONCLUSIONS: This model allows long-term follow-up of cerebral function, lCBF, and reserve capacity in a pathophysiological setting similar to hemodynamic insufficiency in humans.     

2H( gamma,p)n cross section between 20 and 440 MeV

Rate control in acetylcholinesterase (AChE) involves a single anionic site whose anionic center controls rate-related biochemical and conformational changes in the E (free enzyme) and EA (acylated enzyme) conformers. Change in conformer structure and biochemistry affect binding, acylation, and hydrolysis. It is significant that the anionic-esteratic intersite distance is not altered during conformer change as E is converted to EA. In this enzyme system, cationic acetylcholine and anionic AChE are true structural, functional, and biochemical counterparts. The anionic center in the E conformer lies at the bottom of a sterically restricted, hydrophobic cleft < 8 A wide at the top and > 3 A wide at the bottom, while the anionic center in the EA conformer is relatively open. It is characterized by a decrease in the relative binding of hydrophobic cations and by an ability to bind large organic cations. Binding of acetylcholine, H+, or organic cations at the anionic site controls k2(acylation) in the E conformer and k3(hydrolysis) in the EA conformer. Acetylcholine binding forms the ES complex in which the cation maximizes k2. In the EAS complex, the cation reduces k3 and provides allosteric control. Anionic site structure and biochemistry and the effect of pH on k2 and k3 differentiates AChE from butyrylcholinesterase. This comprehensive study of kinetic and thermodynamic processes in AChE was made possible by the synthesis and/or use of families of over 30 cationic and acylation probes of known stereochemistry. They act as rulers of the E and EA conformers of AChE and provide comparative data on kinetic-based and thermodynamic-based constants. Cationic inhibitors affect decarbamylation rates in AChE and provide an additional set of comparative data related to the mechanism of substrate hydrolysis by AChE. Acridine araphanes are unique neural receptor and cholinergic enzyme probes. Their parallel plane and coplanar conformations are related to bridge length. Two parallel plane acridine araphanes are pure uncompetitive inhibitors of AChE. Scatchard plots of the binding of methylacridinium and 9-aminoacridine with the E conformer and 9-aminoacridine with the EA conformer indicate binding at a single anionic site. No ternary complex (EII or EAII) from two-site binding was detected. In AChE, nonspecific, low-level binding at surface ionic and hydrophobic areas is ubiquitous. Binding affinity differences greater than two orders of magnitude distinguish binding at the anionic site from low level binding at surface moieties. Surface binding provides environmental and stability changes in the enzyme but does not modify the fundamental biochemistry of the E and EA conformers.     

Tissue reactions to bacteria-challenged implantable leads with enhanced infection resistance

Tissue reactions to implantable pacemaker leads were investigated in an early infection model in rabbits. Both standard leads and surface-modified leads were used. The surface modification technique was applied to achieve controlled release of the antibiotic gentamicin. The insulating polyurethane tubing material of the leads was provided with an acrylic acid/acrylamide copolymer surface graft and then loaded with gentamicin. Implantation periods varied from day 4, to week 3 1/2, to week 10. We investigated tissue reactions in the absence of an infectious challenge and also the efficacy of surface-modified leads in preventing infection after challenge with Staphylococcus aureus was evaluated. It was demonstrated that the applied surface modification did not induce adverse effects although during early postimplantation an increase in infiltration of granulocytes and macrophages and wound fluid and fibrin deposition were observed. After bacterial challenge, standard leads were heavily infected at each explantation period, denoted by abscesses, cellular debris, and bacterial colonies. In contrast, little or no infection was observed, either macroscopically or by bacterial cultures, with the surface-modified leads. Microscopy showed little evidence of the bacterial challenge, and that primarily at day 4. It was concluded that the applied surface modification demonstrated enhanced infection resistance and thus represents a sound approach to the battle against infectious complications with biomaterials.     

Nasopharyngeal Castleman's disease

A 19-year-old male was admitted to our clinic because of nasal obstruction and intermittent postnasal drip of 3 to 4 years' duration. Physical examination revealed a wide-based, smooth-surfaced nasopharyngeal tumor which was suspected to be a nasopharyngeal angiofibroma after examination of computed tomographic scans and an angiogram. However, after the tumor was removed by surgical excision via a transpalatal approach, the pathologic examination revealed Castleman's disease of the hyaline-vascular type. There was neither evidence of recurrence nor nasal problems at 4 years' follow-up. To our knowledge, Castleman's disease, or angiofollicular lymph node hyperplasia, may present as a local or generalized tumor-like condition, usually in the chest or abdomen, and may involve both the lymph nodes and non-nodal tissues. A review of previous articles reveals that there has not been any report of Castleman's disease found in the nasopharynx. This rare disorder is presented and discussed.     

Purification and characterization of a tumor lipid-mobilizing factor

Cancer patients with weight loss showed urinary excretion of a lipid-mobilizing factor (LMF), determined by the ability to stimulate lipolysis in isolated murine epididymal adipocytes. Such bioactivity was not detectable in the urine of cancer patients without weight loss or in normal subjects. The LMF was purified using a combination of ion exchange, exclusion, and hydrophobic interaction chromatographies to give a single component of apparent Mr 43,000, which showed homology in amino acid sequence with human plasma Zn-alpha2-glycoprotein. Both substances showed the same mobility on denaturing and nondenaturing gels and the same chymotrypsin digestion pattern, both stained heavily for carbohydrate, and they showed similar immunoreactivity. Polyclonal antisera to human plasma Zn-alpha2-glycoprotein was also capable of neutralization of the bioactivity of human LMF in vitro. Using competitive PCR to quantify expression of Zn-alpha2-glycoprotein, we found that only those tumors that were capable of producing a decrease in carcass lipid expressed mRNA for Zn-alpha2-glycoprotein. These results provide strong evidence to suggest that tumor production of Zn-alpha2-glycoprotein is responsible for the lipid catabolism seen in cancer patients.     

Electrostatic effects of smooth muscle calponin on actin assembly

The contribution of electrostatic interactions to the effects of chicken gizzard calponin on the kinetics of actin polymerization and the bundling of F-actin were characterized by a combination of fluorescence, light-scattering, co-sedimentation, and electron-microscopic methods. Stoichiometric amounts of calponin accelerate actin polymerization in low-ionic-strength solutions, but this effect is diminished at [KCI] = 150 mM. At low ionic strengths, micromolar concentrations of calponin induce the formation of large bundles of actin filaments, and lower concentrations of calponin quench the fluorescence of pyrene-labeled F-actin. The latter effect is related to binding of calponin to F-actin rather than to bundling of the filaments. The concentration of calponin required to bundle a fixed concentration of actin filaments increases with increasing ionic strength, as the average diameter of the bundles decreases. Millimolar concentrations of ATP, GTP or ITP are equally efficient at dispersing actin bundles to single filaments or smaller aggregates, even though a significant fraction of calponin remains bound to F-actin. Our findings show that the binding of calponin to actin is determined at least in part by electrostatic interactions, and that the polycationic nature of calponin is primarily responsible for the formation of F-actin bundles via its ability to reduce the electrostatic repulsion between the negatively charged actin filaments.