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W D Kaplan

Publications and source records attributed to W D Kaplan.

84 records · Page 5Linked to original sources
PubMed1970

Patterned neural activity of a mutant Drosophila melanogaster.

Hyperkinetic (1P), a behavioral mutant of Drosophila melanogaster, shows rhythmic leg-shaking action derived from mutation of a single, sex-linked gene. The neural mechanism governing this abnormal motor function consists of rhythmic bursts of activity produced by motor neurons located within the thoracic ganglion. The mechanism of the pattern formation was independent both of sensory information and higher centers in the central nervous system but endogenous within the ganglion. Two types of neurons which appear to be involved in the pattern formation were found within six limited regions.

Action Potentials↗
PubMed1970

Unilaterally patterned neural activity of gynandromorphs, mosaic for a neurological mutant of Drosophila melanogaster.

A neurophysiological study of a behavioral phenotype caused by a sex-linked single gene mutation has been performed with gynandromorphs, mosaic for the mutant gene, Hyperkinetic(1P) (Hk(1P)), in Drosophila melanogaster. The male tissue of this gynandromorph is hemizygous for Hk(1P), while the female tissue is heterozygous. The characteristic neural activity caused by the Hk(1P) gene can be recorded only in the presumptive male region of the thoracic ganglion. Motor regions of one side were found to function independently of their counterparts in the opposite side of the thoracic ganglion and were unaffected by the genotype of other parts of the body. Thus, expression of the Hk(1P) gene is autonomous in the genetic sense, and each side of the ganglion is independent of the other side. Also, there is a high correlation between the external genotype and the genotype of underlying neural tissue of the thorax.

Animals↗
PubMed1969

Dosage compensation for enzyme activities in Drosophila melanogaster.

There are certain genes on the sex chromosome of Drosophila for which the female contains twice as many copies as the male. Some of the genes in this group produce the same phenotype in each sex despite the dosage difference and are said, therefore, to manifest dosage compensation. The structural genes for glucose-6-phosphate and 6-phosphogluconate dehydrogenases are located on the sex chromosome. We measured these enzyme activities in normal flies of each sex and in flies bearing fewer or extra copies of these genes. Normal females (two-dose) had the same 6-phosphogluconate dehydrogenase activity as normal males (one-dose). One-dose females had reduced activity (0.61 of normal) and three-dose females or two-dose males had increased activity (about 1.3 of normal). Triploid females had the normal activity. Glucose-6-phosphate dehydrogenase activity responded similarly to gene dosage. Neither activity responded to changes in the dosage of the gene for the other. These results are compatible with an interpretation whereby each activity is compensated by the products of at least two regulatory genes. One of these regulatory genes is probably sex-linked; the others may be sex-linked or autosomal.

Animals↗
PubMedDate not supplied

Visualization of canine and human prostatic lymph nodes following intraprostatic injection of technetium-99m-antimony sulfide colloid.

Clinically occult lymph node metastases are a frequent finding in patients with carcinoma of the prostate. At present, lymph node dissection is the only reliable method of detecting local nodal spread; we have investigated a nonsurgical technique for demonstrating nodes using intraprostatic injections of 99mTc-Sb2S3. 99mTc-Sb2S3 (1.0 mCi/0.1--0.2 ml) was injected into the prostate glands of nine male mongrel dogs. Scintillation camera images revealed from one to four lymph nodes in each animal with earliest nodal visualization at 1 hour. A study performed on a 64-year-old man with prostatic cancer allowed visualization of seven pelvic lymph nodes, all of which were found to be histologically normal. The simplicity of this technique suggests the potential for both pre- and intraoperative identification of the prostatic lymph nodes. Clinical trials presently underway will allow assessment of the sensitivity and specificity of this technique for the detection of nodal metastases.

Adenocarcinoma↗