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Biomedical subjects

R Blackwell

Publications and source records attributed to R Blackwell.

At least 19 recordsLinked to original sources
PubMed1991

Functional levels of mitochondrial anion transport proteins in non-insulin-dependent diabetes mellitus.

The effect of non-insulin-dependent diabetes mellitus (i.e., NIDDM; type 2 diabetes) on the levels of functional mitochondrial anion transport proteins has been determined utilizing a chemically-induced neonatal model of NIDDM. We hypothesized that moderate insulin deficiency exacerbated by the insulin resistance, which is characteristic of NIDDM, would cause changes in mitochondrial anion transporter function that were similar to those we have previously shown to occur in insulin-dependent diabetes mellitus (i.e., IDDM; type 1 diabetes) (Arch. Biochem. Biophys. 280: 181-191, 1990). Our experimental approach consisted of the extraction of the pyruvate, dicarboxylate and citrate transport proteins from the mitochondrial inner membrane with Triton X-114 using rat liver mitoplasts (prepared from diabetic and control animals) as the starting material, followed by the functional reconstitution of each transporter in a proteoliposomal system. This strategy permitted the quantification of the functional levels of these three transporters in the absence of the complications that arise when such measurements are carried out with intact mitochondria (or mitoplasts). We found that experimental NIDDM did not cause significant changes in the extractable and reconstitutable specific (and total) transport activities of the pyruvate, dicarboxylate, and citrate transporters. These results are in marked contrast to our previous findings obtained using rats with IDDM and negated our hypothesis. The present results, in combination with our earlier findings, allow us to conclude that insulin plays an important role in the regulation of mitochondrial anion transporter function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The effect of insulin supplementation on diabetes-induced alterations in the extractable levels of functional mitochondrial anion transport proteins.

The effect of insulin supplementation on diabetes-induced alterations in the levels of functional mitochondrial anion transport proteins has been determined. The experimental approach consisted of the extraction of the pyruvate, dicarboxylate, and citrate transport proteins from the mitochondrial inner membrane with Triton X-114 using rat liver mitoplasts (prepared from control, diabetic, or insulin-supplemented diabetic animals) as the starting material, followed by the reconstitution of the function of each transporter in a proteoliposomal system. This experimental strategy permitted the quantification of the functional levels of these three transporters in the absence of the complications that arise when such measurements are carried out with intact mitochondria (or mitoplasts). We found that treatment of diabetic rats (i.e., animals that were injected with streptozotocin 3 weeks earlier) on a daily basis with insulin for 3 weeks resulted in a reversal of the diabetes-induced (a) increase in the extractable and reconstitutable total (and specific) transport activities of the pyruvate and dicarboxylate transporters and (b) decrease in the activity of the citrate transporter. These findings indicate that diabetes-induced alterations in the functional levels of mitochondrial anion transport proteins are a direct consequence of the insulin insufficiency that characterizes this disease. Furthermore, this study provides the first demonstration that insulin participates in the regulation of the functional levels of liver mitochondrial anion transport proteins.

Animals↗
PubMed1984

Utilization of general case programming for teaching health education behaviors to students with severe handicaps.

Students with severe handicaps are acquiring safety behaviors through the implementation of systematic instruction. Absent from this instruction is the inclusion of generalization strategies. Included in this article is a procedure for selecting representative teaching examples to promote optimal generalization. This procedure is referred to as general case programming. The steps of this strategy are delineated using an example of applying an adhesive bandage to a cut.

Curriculum↗
PubMed1983

New developments in equipment.

There has been a rapid improvement in ultrasound scanners suitable for obstetric scanning. Design changes have been made which make the equipment more portable, easier to handle and, by means of automation of functions such as TGC, simpler to use. The image quality has increased significantly in terms of better resolution, improved ability to see textural differences between organs, and in sensitivity. These functional changes have been brought about by major improvements in probe construction technology, and by signal processing techniques largely made possible by the use of digital circuitry. The developments in probe design have included the introduction of dynamic focusing to improve resolution and the incorporation of matching layers to improve sensitivity and reduce reverberation. In linear array probes the elements have been subdivided to reduce radial mode noise and grating lobe artefacts. Convex lenses to focus in the out-of-image plane direction are also used. A range of probes designed for special purposes such as duplex scanning, intracavity scanning and intraoperative scanning, have been developed. Needle guides are also available. Signal processing techniques have improved resolution and sensitivity still further. Digital techniques have made textural contrast variable and selectable after the scan has been completed. The use of microprocessors has made measurement from the image and the subsequent use of look up tables very versatile. The same technology will enable instrument upgrades to be a realistic possibility at a time when major developments are very frequent. High speed digitization is making tissue characterization possible.

Female↗
PubMed1976

Carbon fiber-reinforced bone cement in orthopedic surgery.

A tougher, more fatigue-resistant bone cement consisting of short, highmodulus carbon fibers dispersed randomly in normal ply(methyl methacrylate) bone cement has been developed. Fatigue and impact tests are reported that demonstrate the superior fracture resistance and prolonged load-carrying ability of this system. The use of this carbon fiber-reinforced bone cement in the treatment of a pathological fracture of the femur associated with neoplastic disease of the bone is reported. The tougher cement has provided long-term stability of the fracture.

Bone Cements↗