Optical detection of macromolecular heparin via selective coextraction into thin polymeric films

Thin plasticized polymer films, poly(vinyl chloride) doped with a specific ion pairing quaternary ammonium compound, tridodecylmethylammonium chloride, and a lipophilic pH indicator, 3-hydroxy-4-(4-nitrophenylazo)phenyl octadeconate, are shown to exhibit significant and analytically useful optical response toward macromolecular heparin. The response mechanism is based on favorable extraction of heparin into the bulk organic film, owing to the specific ion-pairing complexation reaction between the quaternary ammonium species and the polyanion. A simultaneous coextraction of hydrogen ions results in protonation of the pH chromophore and hence a change in the optical absorbance of the polymeric film. When used in a limited volume/fixed exposure (10 min) detection mode, film absorbances change as a function of the initial heparin concentration in the range of 0.2-3.0 units/mL (1.2-18 micrograms/mL). The practical measurement response time is controlled by heparin diffusion through the stagnant diffusion layer adjacent to the surface of the film as well as within the bulk of the polymer film and is shown to increase with the molecular weight of the heparin species tested. No optical response to heparin is observed when a strong heparin complexing agent (e.g., protamine) is present in the test solution, suggesting that the polymer film can be used to conveniently monitor heparin-protamine (or other antagonist) titrations. The theory relating to the operation of the sensing film in either the equilibrium or the kinetic mode and the selectivity of the optimized film to heparin relative to small anions are presented.     

Nonreducing end structures of chondroitin sulfate chains on aggrecan isolated from Swarm rat chondrosarcoma cultures

Chondrocyte cultures derived from the Swarm rat chondrosarcoma were metabolically labeled with [35S]sulfate or [6-3H]GlcN. Radiolabeled aggrecan was purified from the cell layer and exhaustively digested with chondroitin ABC lyase. Digestion products were resolved into disaccharide and monosaccharide residues using Toyopearl HW40S chromatography. The separated saccharide pools were reduced with NaBH4 and applied onto a CarboPac PA1 column to resolve all of the internal disaccharide alditols (unsaturated) from the nonreducing end disaccharide (saturated) and monosaccharide alditols. Mercuric acetate treatment was used prior to carbohydrate analysis to identify unambiguously the saturated from the unsaturated disaccharides. The chondroitin sulfate (CS) chains from these aggrecan preparations contained: (a) an internal disaccharide composition of unsulfated (3-4 per chain), 4-sulfated (approximately 32 per chain), 6-sulfated (approximately 1 per 14 chains), and 4,6-sulfated disaccharides (approximately 1 per 6 chains) and (b) a nonreducing terminal composition of 4-sulfated GalNAc (approximately 4 out of every 7 chains), 4,6-disulfated GalNAc (approximately 2 out of every 7 chains), and GlcUA adjacent to a 4-sulfated GalNAc residue (approximately 1 out of every 7 chains). Thus, the vast majority of these CS chains terminated with a sulfated GalNAc residue. The presence of 4,6-disulfated GalNAc at nonreducing termini is 60-fold more abundant than 4,6-disulfated GalNAc in interior disaccharides. This observation is consistent with the suggestion that disulfation of terminal GalNAc residues is involved in chain termination.     

Contact areas in the thumb carpometacarpal joint

The thumb carpometacarpal joint is a common site of osteoarthritis. It has been hypothesized that peaks of localized stress on the dorsoradial or volar-ulnar regions, or both, of the articular surfaces of the trapezium and metacarpal lead to erosion of cartilage and may be responsible for the progression of the disease. The objective of this study was to determine the contact areas in this joint under the functional position of lateral (key) pinch and in the extremes of range of motion of the joint. These contact areas were assessed relative to the observed sites of cartilage thinning. Eight hands from cadavers of women and five from cadavers of men were tested in vitro with the thumb under a 25 N load in the lateral pinch position, and under small muscle loads (0-5 N) with the thumb in flexion, extension, abduction, adduction, and neutral positions. Contact areas of articular surfaces of the thumb carpometacarpal joint were determined for these positions using a stereophotogrammetric technique. The lateral pinch position produced contact areas predominantly on the central, volar, and volar-ulnar regions of the trapezium and the metacarpal. In three specimens, contact areas were distinctly separated between the dorsoradial and volar-ulnar regions, and in one specimen, from a man, contact occurred exclusively on the dorsoradial region of the trapezium. Using stereophotogrammetry, maps of cartilage thickness also were determined for a subset of nine specimens. The volar-ulnar, ulnar, and dorsoradial regions of the trapezium were the most common sites of thin cartilage, and these may be sites of cartilage wear.(ABSTRACT TRUNCATED AT 250 WORDS)     

Compulsory notification of cysticercosis in Ribeir?o Preto-SP, Brazil

Cysticercosis is a severe public health problem in several regions of Asia, Africa and Latin America. Epidemiologic studies based on the frequency of cases observed in specialized neurology, neurosurgery and computed tomography services, at autopsy and in seroepidemiologic studies do not permit the determination of the true prevalence of the disease in the population. The objective of the present study was to investigate the prevalence of cysticercosis by compulsory notification. The coefficient of prevalence was 54 cases/100,000 inhabitants in the municipality of Ribeir?o Preto. The results also indicated that cysticercosis is not under control in our region since 21% of cases presented the active form of the disease. Compulsory notification proved to be a valuable resource for the epidemiologic study of cysticercosis, also permitting the mapping of more affected areas for a better direction of prevention strategies.     

Plasma osmolality and brain water content in a rat glioma model

Little is known about how intravenous fluids influence peritumoral edema formation. This experiment was designed to determine, in a rat glioma model, whether changes in plasma osmolality alter water content, as assessed by specific gravity (SpGr), in normal and neoplastic cerebral tissue. Cells cultured from an ethylnitrosourea-induced rat glioma were stereotactically implanted into the right striatum of Fischer 344 rats. A tumor growth interval of 21 days was allowed. In a second experiment, rats underwent a 60-second cortical freeze injury followed by 24 hours' recovery. In both experiments, rats were assigned to one of three groups: hypotonic (100 ml/kg of 0.2 mol/L NaCl in H2O, intraperitoneally; resultant plasma osmolality approximately 268 mOsm/kg); isotonic (no treatment; plasma osmolality approximately 298 mOsm/kg); or hypertonic (10 ml/kg of 1.0 mol/L NaCl in H2O, intraperitoneally; plasma osmolality approximately 342 mOsm/kg). Thirty minutes after fluid injection, regional SpGr was determined using a kerosene-bromobenzene gradient. In subsets of rats, the tissue morphology and blood-brain barrier permeability of Evans blue dye were assessed. Tissue within the freeze lesion was stained by Evans blue dye with sharp demarcation. Evans blue dye did not stain gliomatous tissue, and central necrosis was not histologically evident. In isotonic rats, glioma SpGr was reduced (1.0411 +/- 0.0012 g/ml) relative to the contralateral striatum (1.0437 +/- 0.0008 g/ml; P < 0.001). Despite this, a strong linear relation was observed for SpGr and plasma osmolality in both neoplastic and normal tissue. Within the freeze lesion in isotonic rats, SpGr was severely reduced (1.0335 +/- 0.0008 g/ml; P < 0.0001) compared with contralateral frontal cortex.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adolescent sexuality: Part 4. The practitioner''s role

As no systematic study has been done to get an accurate estimate of the incidence of return to oestrus after first insemination in sows in the Netherlands, the objectives of this investigation were: 1) to obtain an estimate of the incidence of return to oestrus after insemination at the herd level; 2) to investigate the association between incidence of return to oestrus after first insemination and reproduction characteristics in order to get an impression of the economic importance of reproductive failure. These objectives were investigated by using the reproduction results of 240 swine breeding herds in the Southern Netherlands in 1987. This information was obtained from CBK plus computerized herd management records. The average incidence rate of return to oestrus after first insemination at a herd level was 16.9 per 100 first inseminations. The occurrence of return to oestrus after first insemination was distinctly higher in the insemination months July and August compared to the rest of the year. An increased incidence, with 10 returns per 100 first inseminations corrected for confounders in a multiple linear regression model, was associated with a decrease of approximately 0.3 live born piglets/sow/year. A prospective longitudinal study was started in 1988 and 1989 in 37 sow herds. Individual sows were monitored from weaning to first insemination, to the occurrence of return to oestrus, or not, after first insemination, and to farrowing. The investigation focused in particular on the relationship between return to oestrus after first insemination and seroconversion against porcine parvovirus (PPV) and Leptospira interrogans serovar bratislava (L. bratislava).(ABSTRACT TRUNCATED AT 250 WORDS)     

Antiestrogen stimulated human endometrial cancer growth: laboratory and clinical considerations

The new antiestrogen toremifene (TOR) is currently on the market for the treatment of advanced breast cancer in postmenopausal women. TOR is known to exhibit a similar efficacy profile as tamoxifen (TAM) in the treatment of advanced breast cancer and there are studies to suggest that the beneficial side effects of TAM on bone and blood lipids are also achieved with TOR. However, the data concerning the action of TOR on the endometrium is sorely lacking. In light of the estrogenic effect of TAM on the uterus and the 2-3-fold increased incidence in endometrial carcinoma detected in patients receiving TAM therapy, it is imperative to investigate the effect of TOR on endometrial carcinoma. We compared the actions of TAM and TOR on the EnCa101 human endometrial tumor model and find that both antiestrogens have similar growth stimulatory effects. To investigate a potential mechanism of antiestrogen-stimulated endometrial tumor growth, we have examined known activators of the AP-1 signal transduction pathway, the protein kinase C (PKC) family of isozymes, in the EnCa101 human endometrial tumor model. We find that increased PKC isozyme expression correlates with hormone-independent breast cancer as well as antiestrogen-stimulated endometrial cancer.     

Visual evoked potential assessment of the effects of glaucoma on visual subsystems

The purpose of this study is to test the hypothesis that glaucoma leads to selective deficits in parallel pathways or channels. Sweep VEPs were obtained to isolated-check stimuli that were modulated sinusoidally in either isoluminant chromatic contrast or in positive and negative luminance contrast. Response functions were obtained from 14 control subjects, 15 patients with open-angle glaucoma, and seven glaucoma suspects. For all three groups of subjects we found characteristic differences between the VEP response functions to isoluminant chromatic contrast stimuli and to luminance contrast stimuli. The isoluminant chromatic stimulus conditions appeared to favor activity of the P-pathway, whereas the luminance contrast stimuli at low depths of modulation favored M-pathway activity. VEP responses for patients with OAG were significantly reduced for chromatic contrast and luminance contrast conditions, whereas VEP responses for glaucoma suspects were significantly reduced only for the 15-Hz positive luminance contrast condition. Our results suggest that both M- and P-pathways are affected by glaucoma.     

Effects of subchronic administration of metrifonate on cholinergic neurotransmission in rats

The effects of subchronic oral administration of metrifonate, a long-acting cholinesterase (ChE) inhibitor, on cholinergic neurotransmission were assessed in young adult male Wistar rats. Animals were treated twice daily with metrifonate. In a pilot study testing a 100 mg/kg dose of metrifonate for up to 14 days, ChE activity was found to steadily decrease to reach maximum inhibition levels of about 55%, 80% and 35% in brain, erythrocytes and plasma. Steady-state inhibition levels were attained by the 10th day of treatment. When metrifonate-treatment was discontinued, ChE activity in plasma returned to control levels within another day, while erythrocyte and brain ChE activity took more than 2 weeks to recover. In subsequent dose-response studies, metrifonate treatment was given for 3 and 4.5 weeks at doses of 0, 12.5, 25, 50, and 100 mg/kg, to different groups of animals, respectively. Correlation analysis indicted that brain ChE inhibition was more accurately reflected by erythrocyte than by plasma ChE inhibition, although all effects were highly correlated. The changes in ChE activity were not paralleled by changes in other parameters of the cholinergic neurotransmission, such as acetylcholine synthesis rate or acetylcholine receptor binding. It is therefore concluded that repeated administration of metrifonate to rats induces a long-lasting inhibition of ChE activity in a dose-related and predictable manner, which is neither subject to desensitization nor paralleled by counterregulatory downregulation of muscarinic or nicotinic receptor binding sites in brain.