125I]iodopindolol: a new beta adrenergic receptor probe

When utilizing iodohydroxybenzylpindolol (IHYP) as an adrenergic receptor probe in muscle membrane systems, the data demonstrated an unacceptably high nonspecific binding component. Bearer et al. have reported that chloramine-T induced iodination of hydroxybenzylpindolol (HYP) results in the incorporation of iodine into the indole ring rather than into the phenolic moiety as noted previously by others. These results suggest that pindolol itself can also be iodinated. Therefore, the usefulness of carrier free 125I-labeled iodopindolol (IPIN) as an adrenergic receptor probe was investigated. Using between 0.01 nM and 0.1 nM [125I]IPIN in two different muscle membrane systems, we found the nonspecific binding component to be 10% or less of total binding. When [125I]IPIN was used with membranes prepared from rat skeletal muscle, we found it to interact with a single set of high affinity binding sites (KD = 0.13 +/- 0.01 nM) with the characteristics of beta adrenergic receptors and a density of 48.5 fmoles/mg protein. IPIN binding was also studied with purified dog cardiac sarcolemma. A single set of binding sites was detected having a KD of 1.64 +/- 0.5 nM; the density of these sites was 289 fmoles/mg membrane protein. [125I]IPIN may be a useful probe for the beta adrenergic receptor of tissues in which [125I]IHYP and other beta adrenergic receptor probes have a non-specific binding component which approaches that of the specific binding component.     

Agar-Screen Specimen Carrier for Bulk Processing of Biopsy Materials for Electron Microscopy

A specimen carrier for processing large numbers of biopsy materials for epoxy embedding and electron microscopy is described. Commercially available 18-mesh stainless steel or 16-mesh aluminum wire screening is used. The screening is cut into 1 × 3-inch strips. One corner is snipped off for orientation purposes. Four drops of warm 4% agar is placed on a prewarmed standard microscopic glass slide. A thin agar support film is formed on the bottom side of the horizontally held wire screen by lightly running it against the agar. Tissue blocks trimmed to 1 mm³ are blotted on filter paper and placed in a prearranged order on the top surface of the support film. A thin top coating of agar is applied on the specimen by touching it with the tip of a pasteur pipette containing warm 4% agar. The agar-screen unit with the mounted specimens is stabilized in 4% buffered formalin and rinsed with Sorenson's phosphate buffer, pH 7.4, with 6.8% sucrose. It is then processed as a unit through routine osmium tetroxide postfixation, alcohol dehydration, and Epon 812 infiltration. The tissue blocks are plucked off the agar support film with fine-tipped tweezers and embedded in individual capsules. No difficulty in thin sectioning was encountered and examination of the sections under the electron microscope showed good infiltration by the epoxy resin.     

Trans-ethnic variation in germline variants of patients with renal cell carcinoma

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The relationship between narrow and wide bandwidth filter settings during an EMG scanning procedure

This study examined the correlation between EMG values measured with wide (25–1000 Hz) and narrow (100–200 Hz) band-width filters. An EMG diagnostic scan was conducted on 32 chronic pain patients admitted to an inpatient treatment unit. EMG readings were taken from a total of 44 sites (11 sites×2 sides×2 postures). Each EMG measure was passed in parallel through a narrow and wide band-pass filter and the stable readings were recorded. Correlatedt tests and Pearson correlations were used to compare the data from the narrow and wide filter settings. The measures from the wide filter were significantly higher than the measures from the narrow filter. In addition, 61% of the correlations were greater than .90. The majority of the correlations below the median (.93) occurred in the neck region and the abdomen. The implications of the findings are discussed.This research was sponsored by the Swedish Hospital Pain Clinic.     

BIOCHEMICAL CHANGES DURING SEXUAL DEVELOPMENT IN MARCHANTIA POLYMORPHA: I. ESTERASES

Extracts of uninduced thalli, induced thalli, stalks, antheridiophore and archegoniophore disks of Marchantia polymorpha were subjected to starch-gel zone electrophoresis. Developed gels were treated with appropriate reaction mixtures to detect sites of activity for 12 enzyme systems; only phosphatases, esterases, and peroxidases were observed. Although common sites of phosphatase, peroxidase, and esterase activity were detected in all tested extracts, additional sites of peroxidase and esterase activity were found in extracts from antheridiophore disks. The antheridia provided the additional esterases as determined by the electrophoresis of antheridial extracts and by a histochemical test for esterases in sections of antheridiophores.