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Biomedical subjects

P Good

Publications and source records attributed to P Good.

At least 37 records · Page 2Linked to original sources
PubMed1990

Mesoderm induction in Xenopus laevis distinguishes between the various TGF-beta isoforms.

Induction of mesoderm in ectodermal explants of Xenopus laevis blastula embryos had previously been shown to respond selectively to TGF-beta 2, with TGF-beta s 1 and 5 having no activity in this assay. As TGF-beta s 1, 2, and 3 are frequently coexpressed in tissues, we wished to examine the activity of TGF-beta 3 relative to that of TGF-beta s 1 and 2 in this assay as well as in other in vitro assays. We report here that when the activity of recombinant TGF-beta 3 is normalized to that of TGF-beta 1 in the assay for growth inhibition in CCL-64 cells, it is also equal to that of TGF-beta 1 in assays for stimulation of both anchorage-independent growth of rat NRK cells and chemotaxis of human monocytes. In contrast, in the assay for mesoderm induction, recombinant TGF-beta 3 is 10-fold more active than TGF-beta 2, inducing expression of muscle specific alpha-actin at concentrations as low as 1 ng/ml. These results suggest that more complex systems, in contrast to individual cell types, may respond selectively to the various TGF-beta isoforms and that there might be biological consequences of TGF-beta isoform switching in vivo.

Animals↗
PubMed1989

Methadone maintenance program for AIDS-affected opiate addicts.

To slow the spread of AIDS, it may be important for substance abuse treatment programs to give priority admission to patients who are HIV-infected and infectious. A new program is described that provides methadone maintenance treatment to opiate addicts who are "AIDS affected"--heroin addicts diagnosed with AIDS, AIDS-related complex (ARC), or other significant symptoms of HIV infection. The program aims to protect the health of patients and to protect the general public by slowing the spread of the human immunodeficiency virus (HIV). This article describes the program's history and goals, its referral and patient admission process, methods of assessment and treatment planning, medical care, counseling procedures, tolerance for misbehavior, philosophy toward eventual detoxification, and procedures that maintain confidentiality.

AIDS-Related Complex↗
PubMed1988

Proximal chronic inflammatory polyneuropathy with multifocal conduction block.

The pathological findings in proximal and distal nerve biopsy specimens are described in a patient with the clinical and electrophysiological features of chronic inflammatory polyneuropathy with multifocal conduction block. Proximal onion bulb hypertrophic changes in the brachial plexus were associated with inflammatory cell infiltrates. In contrast, the sural nerve biopsy specimen showed a mild picture of mixed axonal degeneration and demyelination-remyelination without inflammatory infiltration.

Action Potentials↗
PubMed1988

Electrophysiology and metallosis: support for an oxidative (free radical) mechanism in the human eye.

Nine cases of metal intraocular foreign body are presented. This study investigates the use of electrodiagnostic techniques in the diagnosis of metallosis and as a prognostic indicator. The electro-oculogram (EOG) and the electoretinogram (ERG) indicate that there are two mechanisms of metallosis, one of which involves cytotoxic damage by siderosomes, and the other lipid peroxidation of photoreceptor outer segments and retinal pigment epithelium. The evidence suggests that the location of the foreign body in the eye determines whether either or both of these mechanisms occur. We propose that these tests can help the ophthalmologist decide when a foreign body has to be removed and give information as to the mechanism of the pathological process.

Biomechanical Phenomena↗
PubMed1985

Cost-effective selection of fire fighter recruits.

To discriminate suitable fire fighters from recurring large groups of applicants, an objective test battery was developed which screened applicants on the basis of physical, psychomotor, and mental abilities. The physical and psychomotor selection procedures first involved fundamental tests of general aerobic endurance, upper body strength, and anaerobic endurance. Successful candidates progressed to more specific tests. Measurements were made of height, weight, hamstring flexibility, balance, strength, upper body flexibility, hand-eye coordination, and the ability to negotiate a fire fighting simulation course. Results of these tests were weighted, allocating 25% to physical tests, 20% to psychomotor tests, and 39% to the simulation course. These scores were then combined with scores of several knowledge tests weighted to be 16% of the whole. This provided a computer-generated ability profile of the top applicants which was considered at their interview before a final selection board of fire service officers. Selected candidates were then required to pass a medical examination. Pearson correlation coefficient analysis of 1984 test results demonstrated general independence of the tests (R = -0.34 to R = 0.52), with the exception of bilateral grip strength (R = 0.77). The first four trials of the selection procedure screened 3,172 applicants, 16.4% of whom were finally selected for interview. City officials estimated that based on a comparison of new and previously used selection procedures, cost savings of +92,500 were being achieved by 1984.

British Columbia↗
PubMed1984

Painful lumbosacral plexopathy with elevated erythrocyte sedimentation rate: a treatable inflammatory syndrome.

Six patients had a syndrome of painful lumbosacral plexopathy and elevated erythrocyte sedimentation rate. Sural nerve biopsy in each case showed axonal degeneration and epineurial arterioles surrounded by mononuclear inflammatory cells. Differential fascicular involvement suggested an ischemic cause in three nerves, but no patient had a necrotizing vasculitis. None of the six patients had vasculitis or cancer. Three of the six were diabetic and were initially thought to have diabetic plexopathy, but deterioration continued despite control of the diabetes. These six patients appeared to have an ischemic neuropathy with an immunological basis. Five were treated with immunosuppressant drugs, and in four the plexopathy improved or was arrested. The pathogenesis is unclear, but postmortem findings in one case suggest that the syndrome does not stem from an underlying vasculitis.

Aged↗
PubMed1983

Morphometric and biochemical studies of peripheral nerves in amyotrophic lateral sclerosis.

Phrenic nerves of 11 patients with amyotrophic lateral sclerosis studied postmortem contained only 33% of the normal number of large myelinated fibers (9 controls; p less than 0.001). In the phrenic nerves of these patients, there were 18% fewer large myelinated fibers in the distal segment than in the proximal segment (p less than 0.025). The ratio of axonal circumference to myelin lamellae in large myelinated fibers in the distal segment was 34% greater than that in control fibers (p less than 0.002). The proportion of acute axonal degeneration was the same at all levels (48.0 +/- 13.7%). Sural nerves of 21 patients with amyotrophic lateral sclerosis had more acute axonal degeneration and 30% fewer myelinated fibers (p less than 0.05) than controls; evidence of degeneration also extended to unmyelinated fibers. The amount of axonal transport of acetylcholinesterase in 9 sural nerves determined in vitro was reduced by 24% (p less than 0.05) and the apparent transport rate was reduced by 44% (p less than 0.01) compared with 4 controls. These findings show that in amyotrophic lateral sclerosis a small degree of dying-back change and of distal axonal atrophy is superimposed on the degeneration of motor neuron cell bodies, and that the disease effects spread beyond the motor neurons.

Acetylcholinesterase↗
PubMed1983

Sympathetic postganglionic unmyelinated axons in the rat peripheral nervous system.

We determined the contribution made to the unmyelinated axon population of the rat peripheral nervous system by sympathetic paravertebral ganglion cells. Sympathectomy, achieved by administration of guanethidine to neonatal rats, led to atrophy of the sympathetic paravertebral ganglion chain, a 95% decrease in peripheral nerve norepinephrine, and loss of 20 to 26% of the unmyelinated axons in a cutaneous nerve (sural), a muscular nerve (nerve to soleus), and a mixed nerve (sciatic). These data indicate that up to a quarter of the total population of peripheral nerve unmyelinated axons are sympathetic ganglia-derived.

Animals↗
PubMed1983

Unmyelinated axon subpopulations in the rat peripheral nervous system.

Using the neurotoxin capsaicin, we examined subpopulations of unmyelinated axons in mixed (sciatic), cutaneous (sural), and muscular (nerve to soleus) nerves. Administration of capsaicin to neonatal rats caused reduction of the sciatic nerve immunoreactive (IR)-substance P (by 45%) and IR-somatostatin (by 84%) contents. This correlated with a substantial reduction in unmyelinated axons in the sciatic and sural nerves (45% and 65%, respectively), although there was no significant decrease in unmyelinated axons in the nerve to soleus. In a parallel study, we have shown that sympathetic ganglia-derived unmyelinated axons account for about 20 to 25% of the total unmyelinated axon population in both the sural nerve and the nerve to soleus. Thus, in the sural nerve, the majority of unmyelinated axons are dorsal root ganglia-derived, contain either substance P or somatostatin, and are capsaicin-sensitive; whereas in the nerve to soleus, the majority of unmyelinated axons are dorsal root ganglia-derived but are insensitive to capsaicin and do not contain substance P or somatostatin. These latter unmyelinated axons presumably contain a yet to be defined neurotransmitter and may be the axons connecting with muscular ergoreceptors, a subpopulation of unmyelinated axons that are biochemically and functionally distinct from the unmyelinated axons of cutaneous nerves.

Animals↗
PubMed1981

Observations on the structure of the eumelanosome matrix in melanosomes of the chick retinal pigment epithelium.

Eumelanosomes from the developing chick pigment epithelium have been isolated, solubilized, and the residue collected. Examination of this material in the electron microscope provides evidence for new structural entities in the eumelanosome and information on the organization of the melanosome. This evidence suggests that there are (1) 190-A fibers arranged in a zigzag fashion, surrounding 240-A-diameter electron-lucent spaces and (2) an internal gridwork enclosing 40-50-A diameter spaces. These two structures are probably alternately layered and "rolled-up".

Animals↗
PubMed1971

Studies on seeds. IV. Lipid composition of bean cotyledon vesicles.

Lipid content has been determined for two types of lipid-rich vesicles isolated from bush bean cotyledon at 24 hr of germination. The larger, nonassociating vesicles are four to six times richer in triglyceride than the smaller vesicles which associate strongly among themselves, as well as with smooth membranes in the cell. The larger vesicles contain about 640 micromoles of phospholipid per gram of protein, while the smaller vesicles have only one-half to two-thirds as much phospholipid per gram of protein. The ratio of individual phospholipids in both kinds of vesicles is close to 20% phosphatidylethanolamine, 60% phosphatidylcholine, and 20% phosphatidylinositol. The fatty acid composition of all phospholipids is similar, and quite different from that of triglyceride, which contains twice as much linolenic acid and less than one-fourth as much palmitic acid. Pea cotyledon has quantitatively the same lipid content as bean cotyledon.

Centrifugation, Density Gradient↗
PubMed1970

Lipid composition of cyanidium.

The major lipids in Cyanidium caldarium Geitler are monogalactosyl diglyceride, digalactosyl diglyceride, plant sulfolipid, lecithin, phosphatidyl glycerol, phosphatidyl inositol, and phosphatidyl ethanolamine. Fatty acid composition varies appreciably among the lipids, but the major ones are palmitic acid, oleic acid, linoleic acid, and moderate amounts of stearic acid. Trace amounts of other acids in the C(14) to C(20) range were also present. Moderate amounts of linolenic acid were found in two strains, but not in a third. The proportion of saturated acid is relatively high in all lipids ranging from about a third in monogalactosyl diglyceride to three-fourths in sulfolipid. This may be a result of the high growth temperature. Lipases forming lysosulfolipid, and lysophosphatidyl glycerol are active in ruptured cells; galactolipid is degraded with loss of both acyl residues. Thus the lipid and fatty acid composition of Cyanidium more closely resembles that of green algae than that of the blue-green algae, although there are differences of possible phylogenetic interest.

Journal Article↗