Growth control of prostatic carcinoma cells in serum-free media: interrelationship of hormone response, cell density, and nutrient media.

Two established prostatic carcinoma cell lines have been grown in long-term culture in a defined medium (PFMR-4) free of serum, hormones, or growth factors. Growth of both lines in serum-free medium was population dependent. This cell-density requirement could be replaced by mitomycin C-inactivated feeder cells, homologous conditioned medium, or fetal bovine serum, but not by hormones or growth factors. The cells responded to these factors only at high density. The nature of this hormonal response was dependent on the kind of basal nutrient medium used. Growth in PFMR-4 with added insulin was more rapid than that in DME/F12 medium with any combination of hormones or growth factors and was substantially greater than growth in DME/F12 medium with insulin alone. The results demonstrate that whereas these two prostatic carcinoma lines (PC-3 and DU 145) do not require hormones for survival or growth, they do respond to certain hormones under appropriate conditions. These conditions include both the type of basal nutrient medium used and the population density.     

Determination of bone mineral density by quantitative computed tomography and single photon absorptiometry in subclinical hyperthyroidism: a risk of early osteopaenia in post-menopausal women

OBJECTIVE There is evidence that treatment with L-thyroxine Increases the risk of early osteopaenia. The aim of our study was to Investigate the effect of subclinical hyperthyroidism in patients on TSH-suppressive L-thyroxine in view of the increased risk of decalcification. DESIGN Measurements of bone mineral density were performed in patients with subclinical hyperthyroidism at different scanning sites of varying trabecular portion. Bone mineral values as well as biochemical data were compared to those of normal controls. PATIENTS Fifty patients (nine men, 25 premenopausal and 16 post-menopausal women) on TSH-suppressive doses of L-thyroxine were investigated after removal of thyroid cancer. MEASUREMENTS Dual energy quantitative computed tomography was used for osteodensitometry in the lumbar spine. Single photon absorptiometry from a ¹²⁶I source was applied to the calcaneus, midshaft radius and distal as well as proximal scanning sites of the distal radius. Normal bone mineral values for each measurement site were taken from healthy reference populations. RESULTS A significant decrease of bone mineral density in the calcaneus was found in 26 of 50 patients. Bone mass assessment yielded a 9.1% decrease of mean bone mineral content in all patients compared to controls (P < 0.01). The decrease in post-menopausal women was 22% (P < 0.001). In premenopausal women bone mineral density changes in the calcaneus were not statistically significant. Cortical measurement sites like the midshaft radlus and the proximal scanning site of the distal forearm showed a 14.8% (P < 0.05) and 10.8% (P= NS) decalcification in post-menopausal women but normal values at the distal scanning site. The lumbar spine was not affected by subclinical hyperthyroidism in either pre or post-menopausal women. In hypoparathyroid patients, bone density did not essentially differ from normals. There was no significant correlation between bone mineral values and duration of treatment or osteocalcin values. CONCLUSIONS Our data suggest that TSH suppressive L-thyroxine treatment has a detrimental effect on the appendicular skeleton in post-menopausal women. Additional effects of oestrogen deficiency and subclinical hyperthyroidism might lead to accelerated bone loss requiring close supervision to determine the smallest dose needed for suppression of the pituitary-thyroid axis.     

Effect of climatic factors and population density on varicella zoster virus epidemiology within a tropical country.

Blood samples were collected from healthy subjects, aged 9 months-29 years in urban and rural communities from 4 distinct regions in Thailand, to determine the seroprevalence rate of varicella-zoster virus (VZV) antibody and its relationship with demographic, climatic, and socioeconomic factors. The overall seroprevalence rate was 52.8% and increased from 15.5% in the 9-month to 4-year-old group to 75.9% in the 20-29 year-olds. The age-adjusted seroprevalence was significantly higher in the cooler than in the warmer regions. In the warmer regions only, the age-specific seroprevalence was significantly higher in the urban population than in the rural population. In Thailand, climate is the main determinant of VZV seroprevalence. The delayed onset of natural immunity is more marked in warmer climate areas. Population density is a secondary determinant; in the warmer areas, the pattern of adolescent and adult susceptibility was greater in rural than in urban areas.     

Azathioprine and diffuse alveolar haemorrhage: the pharmacogenetics of thiopurine methyltransferase.

Current guidelines support the use of corticosteroids and azathioprine as one possible treatment strategy for idiopathic pulmonary fibrosis (IPF). However, some patients with genetic polymorphisms of thiopurine methyltransferase (TPMT) are at risk of severe azathioprine myelotoxicity. The current authors present the case of an 85-yr-old Caucasian male with IPF who developed diffuse alveolar haemorrhage as a complication of azathioprine-induced myelosuppression. Leukocyte genetic TPMT testing revealed that the patient had homozygous polymorphisms associated with the absence of TPMT activity and severe azathioprine-induced myelotoxicity. Thiopurine methyltransferase deficiency should be considered in patients who develop leukopenia early in treatment with azathiopurine, or who present with severe marrow suppression at usual doses. For centres with equipped laboratories, a dosing suggestion is provided based on thiopurine methyltransferase testing. Even with screening strategies, frequent monitoring of complete blood count and liver biochemistry should remain the mainstay of surveillance for azathioprine toxicity.     

Military and government applications of human-machine communication by voice.

This paper describes a range of opportunities for military and government applications of human-machine communication by voice, based on visits and contacts with numerous user organizations in the United States. The applications include some that appear to be feasible by careful integration of current state-of-the-art technology and others that will require a varying mix of advances in speech technology and in integration of the technology into applications environments. Applications that are described include (1) speech recognition and synthesis for mobile command and control; (2) speech processing for a portable multifunction soldier's computer; (3) speech- and language-based technology for naval combat team tactical training; (4) speech technology for command and control on a carrier flight deck; (5) control of auxiliary systems, and alert and warning generation, in fighter aircraft and helicopters; and (6) voice check-in, report entry, and communication for law enforcement agents or special forces. A phased approach for transfer of the technology into applications is advocated, where integration of applications systems is pursued in parallel with advanced research to meet future needs.     

Autoxidation of lipids and antioxidation by alpha-tocopherol and ubiquinol in homogeneous solution and in aqueous dispersions of lipids: unrecognized consequences of lipid particle size as exemplified by oxidation of human low density lipoprotein.

Recent studies on the initial stages in oxidation of low density lipoprotein (LDL) have revealed certain previously unrecognized similarities to emulsion polymerization and some quite unexpected features including the following: (i) ascorbate is an extremely effective antioxidant for LDL containing alpha-tocopherol (alpha-TOH); (ii) in the presence of alpha-TOH and in the absence of both ascorbate and ubiquinol 10 (Q10H2), oxidation of LDL occurs via a free radical chain; (iii) Q10H2 is a much better antioxidant for LDL than alpha-TOH, although the reverse is true in homogeneous systems. We show here that these problems can be solved on the basis of three simple hypothesis, each of which is based on known chemistry: (i) alpha-TOH in LDL can be regenerated from its radical, alpha-TO., by ascorbate; (ii) in the absence of ascorbate and Q10H2, the alpha-TOH in LDL acts as a chain-transfer agent rather than as a radical trap; (iii) Q10H2 is a much more effective chain-breaking antioxidant than alpha-TOH in LDL because the semiquinone radical Q10H. exports its radical character from the LDL into the aqueous phase. Our conclusions imply that the search for better antiatherosclerotic drugs might profitably focus on antioxidants capable of exporting radicals from LDL particles or otherwise increasing the traffic of radicals between particles.     

Asymptotic solution of the cylindrical nonlinear Poisson-Boltzmann equation at low salt concentration: analytic expressions for surface potential and preferential interaction coefficient

The analytic solution to the nonlinear Poisson-Boltzmann equation describing the ion distributions surrounding a nucleic acid or other cylindrical polyions as a function of polyion structural quantities and salt concentration ([salt]) has been sought for more than 80 years to predict the effect of these quantities on the thermodynamics of polyion processes. Here we report an accurate asymptotic solution of the cylindrical nonlinear Poisson-Boltzmann equation at low to moderate concentration of a symmetrical electrolyte (< or = 0.1 M 1:1 salt). The approximate solution for the potential is derived as an asymptotic series in the small parameter var epsilon(-1), where var epsilon identical with kappa(-1)/a, the ratio of the Debye length (kappa(-1)) to the polyion radius (a). From the potential at the polyion surface, we obtain the coulombic contribution to the salt-polyelectrolyte preferential interaction (Donnan) coefficient (Gamma(u)coul) per polyion charge at any reduced axial charge density xi. Gamma(u)coul is the sum of the previously recognized low-salt limiting value and a salt-dependent contribution, analytically derived here in the range of low-salt concentrations. As an example of the application of this solution, we obtain an analytic expression for the derivative of the midpoint temperature of a nucleic acid conformational transition with respect to the logarithm of salt concentration (dT(m)/d ln[salt]) in terms of [salt] and nucleic acid structural quantities. This expression explains the experimental observation that this derivative is relatively independent of salt concentration but deviates significantly from its low-salt limiting value in the range 0.01-0.1 M.     

Phagocytosis of aggregated lipoprotein by macrophages: low density lipoprotein receptor-dependent foam-cell formation.

Low density lipoprotein (LDL) modified by incubation with phospholipase C (PLC-LDL) aggregates in solution and is rapidly taken up and degraded by human and mouse macrophages, producing foam cells in vitro. Human, mouse, and rabbit macrophages degraded 125I-labeled PLC-LDL (125I-PLC-LDL) more rapidly than native 125I-labeled LDL (125I-LDL), while nonphagocytic cells such as human fibroblasts and bovine aortic endothelial cells degraded 125I-PLC-LDL more slowly than 125I-LDL. This suggested the mechanism for internalization of PLC-LDL was phagocytosis. When examined by electron microscopy, mouse peritoneal macrophages appeared to be phagocytosing PLC-LDL. The uptake and degradation of 125I-PLC-LDL by human macrophages was inhibited greater than 80% by the monoclonal antibody C7 (IgG2b) produced by hybridoma C7, which blocks the ligand binding domain of the LDL receptor. Similarly, methylation of 125I-LDL (125I-MeLDL) prior to treatment with phospholipase C decreased its subsequent uptake and degradation by human macrophages by greater than 90%. The uptake and degradation of phospholipase C-modified 125I-MeLDL by macrophages could be restored by incubation of the methylated lipoprotein with apoprotein E, a ligand recognized by the LDL receptor. These results indicate that macrophages internalize PLC-LDL by LDL receptor-dependent phagocytosis.     

Molecular and cellular imaging of atherosclerosis: emerging applications.

Molecular imaging studies have shed light on important biological aspects of atherosclerosis, and are now entering the clinical arena for the detection of clinical atheroma. This review first discusses fundamental principles regarding the rationale for and development of molecular imaging technologies for investigating atherosclerosis. Next, we highlight clinically promising imaging strategies that illuminate key biological aspects of atherosclerosis, including macrophage activity, protease activity, lipoprotein presence, apoptosis, and angiogenesis. We envision that several molecular imaging approaches will become important adjuncts to the clinical management of high-risk atherosclerosis.     

Electrocardiographic imaging: II. Effect of torso inhomogeneities on noninvasive reconstruction of epicardial potentials, electrograms, and isochrones

INTRODUCTION: Noninvasive electrocardiographic imaging (ECGI) involves inverse reconstruction of epicardial potentials, electrograms (EGMs), and isochrones from body surface potential maps (BSPMs). The heart lies in a volume conductor that includes lungs, blood, bone, muscle, and fluid. We investigate the effects of these torso inhomogeneities on reconstructed epicardial potentials, EGMs, and isochrones to address the issue of whether they should be included in clinical ECGI methodology. METHODS AND RESULTS: Potential data were obtained for different pacing protocols from a dog heart suspended in a human-shaped torso tank. Accurate geometry of torso inhomogeneities was digitized from the Visual Human Project and appropriately introduced into a computer model of the torso. Three models were used: accurate inhomogeneous torso, homogeneous torso, and a torso with stylized lungs (to generate an approximate model). The inhomogeneous model was used to compute BSPMs from the measured epicardial potentials. These BSPMs were the starting point for inverse computations in the different torso models. Epicardial potential maps, EGMs, and isochrones were computed. The homogeneous model produced slightly less accurate epicardial potential reconstructions than the inhomogeneous model and stylized lung model, but epicardial potential patterns, EGMs, isochrones, and locations of pacing sites were reconstructed with comparable accuracy when torso inhomogeneities were ignored. CONCLUSION: The results demonstrate that, in the clinical application, it is not necessary to include torso inhomogeneities for noninvasive reconstructions of epicardial potentials, EGMs, and activation sequences.     

Modification of low density lipoprotein by endothelial cells involves lipid peroxidation and degradation of low density lipoprotein phospholipids.

Low density lipoprotein (LDL) incubated with cultured endothelial cells from rabbit aorta or human umbilical vein is altered in several ways (EC-modified): (i) It is degraded by macrophages much faster than LDL similarly incubated in the absence of cells or incubated with fibroblasts. (ii) Its electrophoretic mobility is increased. (iii) Its density is increased. We report here that antioxidants completely prevent these changes. We also report that these changes do not take place if transition metals in the medium are chelated with EDTA. During EC-modification as much as 40% of the LDL phosphatidylcholine is degraded to lysophosphatidylcholine by a phospholipase A2-like activity. When incubation conditions in the absence of cells were selected to favor oxidation--for example, by extending the time of incubation of LDL at low concentrations, or by increasing the Cu2+ concentration--LDL underwent changes very similar to those occurring in the presence of cells, including degradation of phosphatidylcholine. Hence, some phospholipase activity appears to be associated with the isolated LDL used in these studies. The results suggest a complex process in which endothelial cells modify LDL by mechanisms involving generation of free radicals and action of phospholipase (s).     

Calculation of atrioventricular compliance from the mitral flow profile: analytic and in vitro study.

The quantitative assessment of ventricular diastolic function is an important goal of Doppler echocardiography. Hydrodynamic analysis predicts that the net compliance (Cn) of the left atrium and ventricle can be quantitatively predicted from the deceleration rate (dv/dt) of the mitral velocity profile by the simple expression: Cn = - A/rho dv/dt, where A is effective mitral valve area and rho is blood density. This formula was validated using an in vitro model of transmitral filling where mitral valve area ranged from 0.5 to 2.5 cm2 and net compliance from 0.012 to 0.023 cm3/(dynes/cm2) (15 to 30 cm3/mm Hg). In 34 experiments in which compliance was held constant throughout the filling period, net atrioventricular compliance was accurately calculated from the E wave downslope and mitral valve area (r = 0.95, p less than 0.0001). In a second group of experiments, chamber compliance was allowed to vary as a function of chamber pressure. When net compliance decreased during diastole (as when the ventricle moved to a steeper portion of its pressure-volume curve), the transorifice velocity profile was concave downward, whereas when net compliance increased, the velocity profile was concave upward. Application of the preceding formula to these curved profiles allowed instantaneous compliance to be calculated throughout the filling period (r = 0.93, p less than 0.001). Numeric application of a mathematic model of mitral filling demonstrated the accuracy of this approach in both restrictive and nonrestrictive orifices.(ABSTRACT TRUNCATED AT 250 WORDS)     

Secondary structure of complement component C3a anaphylatoxin in solution as determined by NMR spectroscopy: differences between crystal and solution conformations.

Two-dimensional 1H NMR investigations were used to locate elements of regular secondary structure in the human complement protein C3a (the des-Arg77 derivative) in solution. The results were compared to a refined crystal structure based on the 3.2-A resolution structure of des-Arg77-C3a [Huber, R., Scholze, H., Paques, E. P. & Deisenhofer, J. (1980) Hoppe-Seyler's Z. Physiol. Chem. 361, 1389-1399]. In excellent agreement with the x-ray data, helices occur in the regions of residues 17-28 and 36-43 in solution. In contrast to the x-ray data, where a third long helix was found from residue 47 to residue 73, the solution data show a shorter helix in the region from residue 47 to residue 66, followed by a transition range at positions 67-70, leading into a six-residue carboxyl-terminal peptide in dynamic random coil conformation. At the amino terminus, a well-defined helix is observed in solution for the residues 8-15 region, which, like the carboxyl terminus, gradually changes to dynamic random coil toward the end of the polypeptide chain. This is at variance with the x-ray data as well, in which residues 13-15 are nonhelical and no electron density could be assigned to the first 12 residues due to disorder.     

Antagonists of activin signaling: mechanisms and potential biological applications.

Activins are members of the transforming growth factor-beta (TGF-beta) superfamily that control many physiological processes such as cell proliferation and differentiation, immune responses, wound repair and various endocrine activities. Activins elicit these diverse biological responses by signaling via type I and type II receptor serine kinases. Recent studies have revealed details of the roles of inhibin, betaglycan, follistatin and its related protein follistatin-related gene (FLRG), Cripto and BAMBI in antagonizing activin action, and exogenous antagonists against the activin type I (SB-431542 and SB-505124) and type II (activin-M108A) receptors have been developed. Understanding how activin signaling is controlled extracellularly is the first step in providing treatment for wound healing and for disorders such as cachexia and cancer, which result from a deregulated activin pathway.     

Overestimation of infarct size by quantitative two-dimensional echocardiography: the role of tethering and of analytic procedures

Analyses of regional left ventricular systolic wall motion or thickening overestimate infarct size. We used quantitative two-dimensional echocardiographic analysis of systolic thickening and contrast two-dimensional echocardiography to evaluate causes for that overestimation. The following possibilities were considered: "tethering," defined as dysfunction of contrast-enhancing myocardium adjacent to ischemic or contrast-negative regions, and the role of standard center of mass analysis algorithms, which may overestimate wall motion abnormalities because of the axis shift produced by simultaneous systolic expansion of the ischemic segment and systolic contraction of the nonischemic segment. In the short-axis view in 12 animals, the echo contrast defect (ECD) occupied 32 +/- 7% of the left ventricular circumference. Extent of dysfunction by the center of mass analysis was 39 +/- 5% of the left ventricular circumference and correlation with ECD size was .68 (SEE = 5.2%). Thus 8 +/- 6% of the circumference of the left ventricle was assessed to be dysfunctional yet enhanced with contrast. Tethering accounted for only half of this (4 +/- 4% of left ventricular circumference) and involved less than 1 cm on either side of the ECD. The remaining overestimation by the center of mass analysis correlated significantly (r = .89, p less than .01) with the amount of systolic expansion of the ECD. This expansion of the ECD (increase in angle subtended by the ECD of 11 +/- 8%) was produced by the systolic shift in the center of mass toward the dysfunctional segment from contraction of the opposite, nonischemic segment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ursodeoxycholic acid: Mechanism of action and novel clinical applications.

Ursodeoxycholic acid (UDCA) is used in the treatment of cholestatic liver diseases, gallstone dissolution, and for patients with hepatitis C virus infection to ameliorate elevated alanine aminotransferase levels. The efficacy of UDCA treatment has been debated and the mechanisms of action in humans have still not defined. Suggested mechanisms include the improvement of bile acid transport and/or detoxification, cytoprotection, and anti-apoptotic effects. In this review, we summarize the proposed molecular mechanisms for the action of UDCA, especially in hepatocytes, and also discuss the putative future clinical usage of this unique drug.     

Treatment of symptomatic diffuse esophageal spasm by endoscopic injections of botulinum toxin: a prospective study with long-term follow-up.

BACKGROUND: Diffuse esophageal spasm is a rare esophageal motility disorder for which there are no satisfactory pharmacologic alternatives for treatment. The aim of this study was to investigate whether botulinum toxin (BTX) injection is an effective short- and long-term treatment for patients with symptoms caused by diffuse esophageal spasm. Whether recurrence of clinical symptoms can be successfully retreated by BTX injection was also studied. METHODS: Nine symptomatic patients (6 women, 3 men; 57-86 years) with manometrically proven diffuse esophageal spasm underwent BTX injection. One hundred IU BTX were diluted in l0 mL of saline solution and injected endoscopically at multiple sites along the esophageal wall beginning in the region of the lower esophageal sphincter and moving proximally in 1- to 1.5-cm intervals, and into endoscopically visible contraction rings. Symptom scores based on an analogue scale for dysphagia, regurgitation, and noncardiac chest pain were assessed before and after therapy, 1 day thereafter, and at 1 and 6 months. RESULTS: Symptoms improved immediately in 7 (78%) patients after 1 injection session. After 4 weeks 8 (89%) patients were in remission with a decrease in total symptom score. The total symptom score decreased from a median 8.0 (interquartile range: 6.75; 9.0) before treatment to 2.0 (1.5; 3.75) after 1 day (p < 0.01) and to 2.0 (interquartile range: 0.75; 3.0) after 1 month (p < 0.01). After 6 months all 8 patients with a response at 1 month still had a symptom score of 3 or less without further treatment. Subsequently 4 patients required reinjection 8, 12, 15, or 24 months after the initial treatment with similarly good results. No serious adverse effects were observed. CONCLUSIONS: BTX injection at several levels of the tubular esophagus is an effective treatment for patients with symptoms caused by diffuse esophageal spasm. Symptom relapse can be effectively treated by repeated BTX injection.