Enhancement by tetraphenylborate of technetium-99m-MIBI uptake kinetics and accumulation in cultured chick myocardial cells

Myocellular uptake and retention of technetium-99m-hexakis (2-methoxyisobutylisonitrile) (Tc-MIBI), a lipophilic cationic myocardial perfusion and viability imaging agent, is dependent on both mitochondrial and plasma-membrane potentials. To test for enhancement of uptake kinetics by lipophilic anions, cultured chick heart cells were exposed to tetraphenylborate (TPB), which produced a concentration-dependent maximal 15-fold increase in Tc-MIBI uptake kinetics (at 3 x 10(-5) M) and enhanced peak accumulation of Tc-MIBI from 165.4 +/- 26.3 to 705.6 +/- 61.3 fmoles/mg protein.nMo (P less than 0.001). Carbonyl cyanide-m-chloro phenylhydrazone (CCCP; 10(-5) M), a mitochondrial uncoupler, rapidly depleted cellular content of Tc-MIBI in the presence of TPB (10(-5) M) from 300.0 +/- 30.0 to 42.5 +/- 1.9 fmole/mg protein.nMo (p less than 0.001). TPB enhanced both uptake rates and net accumulation of Tc-MIBI at all buffer Ko concentrations between 130 mM and 0.54 mM. Tc-MIBI influx rates allowed estimation of plasma-membrane potential as a function of Ko in the presence of valinomycin with a slope of -67 mV/decade (r = -0.99). The results further support a potential-dependent mechanism for cell uptake of Tc-MIBI and suggest a rational approach for increasing tissue extraction fraction in vivo.     

Arterialized tendocutaneous venous flap for dorsal finger reconstruction

We describe three cases of combined loss of skin and tendon on the dorsum of the finger that were reconstructed with venous flaps. The technique is feasible and offers a good treatment modality for the small but complex defect on the dorsum of the finger by a one-stage operation. © 1994 Wiley-Liss, Inc.     

Current perspectives on papillary carcinoma of the thyroid gland.

Papillary carcinoma is the most common of the carcinomas of the thyroid gland, but it is also the one with the best prognosis. At the present, diagnosis is best done by fine needle aspiration, and treatment by surgical resection. With recent advances in molecular and cellular biology, diagnosis and therapy in the future may depend on micromolecular technologies. The prognosis is promising for increased success in the treatment of papillary carcinoma.     

The Saturation Characteristics of Glucose Transport in Bovine Retinal Pigment Epithelium

Purpose: To study the saturation characteristics of the glucose transport across the bovine retinal pigment epithelium(RPE).Methods :The bovine RPE preparations were munted with a modified Ussing chamber. The L-[3H]-glucose and 3-0-methyl-D-[14C]-glucose fluxes across the RPE from the choroid to retina were studied at different glucose concentrations.Results: The glucose transport was found to be stereospecific, with 3-0-methyl-D-glucose (MDG) being transported about three times faster than L-glucose. The glucose transport showed typical saturation characteristics in Michaelis-Menten fashion. The Vmax and the Km of corrected MDG were 2452 nmol cm-2h-1 and 30.8 mM respectively. It was shown that the glucose transport system was saturated at 61.6 mM.Conclusions : The saturation characteristics of the corrected MDG flux suggested that the capacity of glucose transport through the bovine RPE is immense. Eye Science 1998; 14: 726 -729.     

A Clinico-Pathological Analysis of Seventeen Cases of Non-Hodgkin'S Lymphoma Involving the Orbit

Seventeen patients with non-Hodgkin's lymphoma involving the orbit were studied. There were 12 males and 5 females and their median age was 53 years. Three cases were classified as stage I, two as stage II and 12 as stage IV. the histology was small lymphocytic type in 4 of the 5 stage I and II cases, and immunophenotyping, confirming their B-cell origin, was performed in two of these cases. All stage I and II patients responded favourably to local radiotherapy alone. the 12 stage IV patients had a marked male predominance and more commonly an intermediate grade histology and T-immunophenotype. Several of the orbital lesions seemed to represent extension of nasal lymphomas. the stage IV patients had a poorer survival than the stage I and II patients but the difference was not statistically significant, probably due to the small number of patients.     

Nonlinear analysis of heart rate dynamics in hyperthyroidism

Studies on the physiology of the cardiovascular system suggested that the generation of the heart rate signal is governed by nonlinear chaotic dynamics. No study investigated the nonlinear dynamics of heart rate in hyperthyroidism. We examined whether the heart rate dynamics of hyperthyroid patients is different from normal controls by the nonlinear analysis of heart rate variability (HRV) with correlation dimension (CD). Thirty-three hyperthyroid Graves' disease patients (30 females and 3 males; age 31 +/- 1 years, means +/- SE) and 33 sex-, age-, and body mass index-matched normal controls were recruited to receive one-channel electrocardiogram recording for 30 min. The CD, an index of complexity, was computed from the sequence of normal R-R intervals by the Grassberger and Procaccia algorithm. Compared to the normal controls, the hyperthyroid patients showed significant reductions (P < 0.001) in the mean R-R interval (hyperthyroid 616 +/- 15 versus control 868 +/- 16 ms), the standard deviation of R-R intervals (25 +/- 2 versus 54 +/- 4 ms) and CD (5.02 +/- 0.11 versus 6.42 +/- 0.16). Our study demonstrated for the first time that hyperthyroid patients and normal controls could be distinguished by CD analysis of HRV. In addition, the decreased CD in hyperthyroid patients implies reduced complexity and impaired tolerance to cardiovascular stresses in hyperthyroidism. This finding helps to explain exercise intolerance and irritability manifested by the hyperthyroid patients.     

Modulation of cancer cell survival pathways using multivalent liposomal therapeutic antibody constructs

Various methods have been explored to enhance antibody-based cancer therapy. The use of multivalent antibodies or fragments against tumor antigens has generated a great deal of interest, as various cellular signals, including induction of apoptosis, inhibition of cell growth/survival, or internalization of the surface molecules, can be triggered or enhanced on extensive cross-linking of the target/antibody complex by the multivalent form of the antibody. The goal of the studies reported here was to develop multivalent antibody constructs via grafting of antibody molecules onto liposome membranes to enhance antibody activity. Using trastuzumab and rituximab as examples, up to a 25-fold increase in the antibody potency in cell viability assay was observed when the antibodies were presented in the multivalent liposome formulation. Key cell survival signaling molecules, such as phosphorylated Akt and phosphorylated p65 nuclear factor-kappaB, were down-regulated on treatment with multivalent liposomal trastuzumab and liposomal rituximab, respectively. Potent in vivo antitumor activity was shown for liposomal trastuzumab. The data presented here showed the potential of liposome technology to enhance the therapeutic effect of antibodies via a mechanism that modulates cell survival through clustering of the target/antibody complex.     

Crystallization and Morphological Features of Syndiotactic/Atactic Polystyrene Blends at High Temperatures

Crystalline/amorphous binary mixtures of polystyrene with different tacticities, syndiotactic/atactic isomers (sPS/aPS), have been systematically studied to reveal the composition dependence of the blend morphologies, i.e., sPS lamellar structure and aPS diluent segregation, developed after isothermal crystallization. To reveal the molecular weight effect of the aPS diluents, four different of aPS were used to prepare blends with various compositions. After being melt crystallized isothermally at 250 °C, all blends were investigated by means of POM, WAXS, and SAXS as well as SEM and TEM to reveal the spherulitic and lamellar morphologies developed.