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Biomedical subjects

L Kass

Publications and source records attributed to L Kass.

At least 19 recordsLinked to original sources
PubMed1992

A circadian clock in the Limulus brain transmits synchronous efferent signals to all eyes.

A circadian clock in the brain of the horseshoe crab, Limulus polyphemus, has an important role in the function of the peripheral visual system. At night, the clock transmits neural activity to the lateral, ventral, and median eyes via efferent optic nerve fibers. The activity occurs in synchronous bursts (maximum rate of 2 bursts/s) with individual efferent fibers contributing a single spike in each burst. The circadian efferent activity originates in the protocerebrum. Lateral connections synchronize the efferent activity recorded from the two halves of the protocerebrum, suggesting the existence of bilateral circadian oscillators. Circadian efferent activity survives excision of the brain and isolation of the protocerebrum. We conclude that circadian clock and its complex neural circuitry are fundamental components of the Limulus visual system.

Animals↗
PubMed1992

Basic blue 54: a new colorant for monocytes.

C.I. basic blue 54, a sulfur containing azo textile dye, stained the nucleus and cytoplasm of normal and leukemic monocytes bright red-violet. Essential for the staining reaction was a brief final rinse in a pH 3.6 acetic acid-sodium acetate buffer. Coloration of the type found in monocytes was not observed in other types of mature and immature leukocytes.

Azo Compounds↗
PubMed1992

A two step stain for normal and leukemic monocytes using two different dyes applied in sequence.

A staining procedure for monocytes in specimens of blood and bone marrow was developed. The technique was a two step procedure in which unfixed cells were exposed first to a methanolic solution of C.I. basic blue 54. Next, an aqueous alkaline buffered solution of C.I. basic blue 141 was added to the first staining solution. After staining for 10 min in the solution with two stains, slides or coverslips were washed for 5 sec in pH 5.6 phosphate buffer and drained dry. The cytoplasm of monocytes stained intensely deep purple and frequently nuclei were stained red. Similar staining was not found in other types of normal or abnormal blood and bone marrow cells.

Buffers↗
PubMed1991

Visual performance of horseshoe crabs day and night.

A circadian clock modulates the structure and function of the lateral eyes of Limulus polyphemus, greatly increasing their sensitivity at night. During the mating season, male Limulus are visually attracted both day and night to females and objects that resemble females. This paper asks how well Limulus can see day and night, and whether the circadian changes in retinal sensitivity might influence the ability of these animals to find mates. We recorded the visual behavior of male and female horseshoe crabs in the vicinity of an object--a cement hemisphere (29.5 cm diameter) similar in size and shape to a female horseshoe crab--placed in a mating area near Mashnee Dike, Bourne, Massachusetts. Males oriented toward this target from an average distance of 0.94 m during the day and 0.88 m at night; and females appeared to avoid the target. We conclude that males can see potential mates at night almost as well as they can during the day. Apparently the circadian changes in the retina help compensate for the daily changes in illumination in the animal's normal environment. This study provides the first evidence for a role of visual circadian rhythms in an animal's natural behavior.

Animals↗
PubMed1991

Basic blue 75: a new stain for erythroblasts.

C.I. basic blue 75 in an aqueous alkaline solution stains the nuclei of mature and immature erythroblasts bright red. Simultaneously, the stain colors the cytoplasm of erythroblasts blue in immature cells and purple in mature cells. Colors of the type described were not found in other normal and abnormal hematopoietic cells.

Bone Marrow↗
PubMed1990

New stains for blood and bone marrow cells.

Traditionally, blood and bone marrow cells have been identified based on their characteristic shapes and colors when stained with one of several panoptic stains including Wright's or Giemsa's. As questions arose regarding the origin of normal and leukemic cells, cytochemical stains were developed. These stains help identify cells on the basis of a distinctive metabolite or enzyme. As part of an ongoing tradition in which textile dyes are used for biological staining, several new stains have been applied to hematologic staining. These include C.I. basic blue 41, basic blue 141, basic blue 93, and an asymmetrical polymethine dye. As additional cell-selective stains are developed, we can anticipate further improvements in our ability to identify normal and malignant hematopoietic cells.

Blood Cells↗
PubMed1979

Connections of the tectum of the rattlesnake Crotalus viridis: an HRP study.

We have studied the connections of the tectum of the rattlesnake by tectal application of horseradish peroxidase. The tectum receives bilateral input from nucleus lentiformis mesencephali, posterolateral tegmental nuclei, anterior tegmental nuclei and periventricular nuclei; ipsilateral input from nucleus geniculatus pretectalis, and lateral geniculate nucleus pars dorsalis; and contralateral input from dorso-lateral posterior tegmental nucleus and the previously undescribed nucleus reticularis caloris (RC). RC is located on the ventro-lateral surface of the medulla and consists of large cells 25--45 micrometer in diameter. Efferent projections from the tectum can be traced to the ipsilateral nucleus lentiformis mesencephali, the ipsilateral lateral geniculate region, anterior tegmental region and a wide bilateral area of the neuropil of the ventral tegmentum and ventral medualla. We have not found any direct tectal projections from the sensory trigeminal nuclei including the nucleus of the lateral descending trigeminal tract (LTTD). We suggest that in the rattlesnake, RC is the intermediate link connecting LTTD to the tectum.

Animals↗
PubMed1979

Acid phosphatase in leukemic blasts: characterization by isoelectric focusing in polyacrylamide gel.

Using the high resolution technique of isoelectric focusing in polyacrylamide gel, isoenzymatic components of acid phosphatase were detected in cell-free extracts prepared from different cytologic types of leukemic blasts in adults. Results indicate that for different cytologic types, different characteristic patterns of acid phosphatase isoenzyme could be detected. These studies extend conventional cytochemistry and indicate that characteristic patterns of acid phosphatase isoenzyme can be detected for various cytologic types of acute leukemia.

Acid Phosphatase↗
PubMed1979

Specificity of serotoninergic inhibition in Limulus lateral eye.

The receptor specificity for synaptically mediated lateral inhibition in Limulus lateral eye retina was studied by structure-activity correlations of the action of the putative indoleaminergic neurotransmitter, serotonin (5-HT), and its isomers and structural analogs, tryptamine (TRYP), 6-hydroxytryptamine (6HT), 5,6-dihydroxytryptamine (5,6-DHT), 5-hydroxydimethyltryptamine (5-HDMT), and 5-hydroxytryptophan (5-HTP). The 5-HT blockers, lysergic acid diethylamide (LSD), bromo-LSD (BOL), and cinanserin, were also tested. The inhibitory action of the indoleaminergic agonists is highly structure-specific. An hydroxyl group in the 5 position of the indole nucleus, sterically unencumbered by hydroxyls in neighboing positions, is essential. In order of decreasing potency, 5-HT, 5-HDMT, and 5-HTP are active agonists; TRYP, 6-HT, and 5,6-DHT are inactive. Configuration and mobility of the side chains of the active agonists also affect the interaction, and these side-chain characteristics correlate with agonist potency. The receptors for inhibitory action and for transmembranal transport in reuptake are different. Both active agonists and inactive analogs appear to be taken up (Adolph and Ehinger, 1975. Cell Tissue Res. 163:1-14). LSD and BOL have bimodal actions: direct inhibition and agonist blockade. These actions may be mediated via low-specificity presynaptic uptake receptor sites rather than highly specific, postsynaptic, agonist receptor sites.

5-Hydroxytryptophan↗
PubMed1979

Cytochemical identification of tetrahydrofolate in human leukocytes.

Utilizing the ability of molybdenum dioxide dichloride to form a black insoluble precipitate with tetrahydrofolate, a cytochemical test for rapid detection of tetrahydrofolate in human leukocytes was developed. The test may be useful in distinguishing deficiency of vitamin B12 or folate or both from other disorders of erythropoiesis characterized by megaloblastic erythropoiesis.

Anemia, Pernicious↗
PubMed1979

Nonspecific esterases in leukemic blasts. Characterization by isoelectric focusing in polyacrylamide gel.

Using high-resolution technics of isoelectric focusing in polyacrylamide gel, isoenzymatic components of nonspecific esterases extracted from various cytologic types of leukemic blasts were visualized using alpha-naphthyl acetate and alpha-naphthyl butyrate as substrates. For each cytologic type of leukemic blast, consistent and distinctive patterns of nonspecific esterase activity were visualized. These studies provide further evidence for heterogeneity of nonspecific esterases, and for elaboration of isoenzymatic components as a reflection of cellular differentiation.

Esterases↗
PubMed1979

Cytochemistry of esterases.

Esterases are enzymes that cleave aliphatic and aromatic ester bonds. With the use of synthetic substrates, esterases can be demonstrated in hematopoietic cells. Using alpha naphthyl acetate or alpha naphthyl butyrate, nonspecific esterase activity can be demonstrated. Intense activity of nonspecific esterase that is inhibited by fluoride is characteristic of cells of monocytic or reticulum cell origin. Using naphthol ASD-chloroacetate, specific esterase activity can be detected. Specific esterase is a lysosomal enzyme and is a useful marker for cells of granulocytic origin. Distinctive patterns of specific and nonspecific esterase activities are found in marrow cells from patients with various types of hematologic disorders. With the use of electrophoretic techniques, isoenzymatic analysis of esterases can be achieved.

Animals↗
PubMed1979

New aspects of preleukemic disorders.

Preleukemic disorders are a controversial group of panmyelopathic disturbances that often precede the emergence of acute myeloblastic or myelomonocytic leukemia. In most instances, these preleukemic disorders are characterized by slowly developing myeloblastosis of the bone marrow. They include preleukemia, primary acquired panmyelopathy with myeloblastosis or smouldering acute leukemia, erythroleukemia, and subacute myelomonocytic leukemia. Sometimes, transitions between these various preleukemic disorders may be observed in a single individual. Abnormalities in cellular differentiation are expressed in cytochemical aberrations and in elaboration of colony forming units by marrow cells of patients with preleukemic disorders. Cytogenic and cellular kinetic abnormalities link preleukemic disorders closely to acute myeloblastic or myelomonocytic leukemia, although in many patients with preleukemic disorders, conversion to acute leukemia is not observed or perhaps not recognized. Understanding pathogenetic and pathophysiological aspects of preleukemic disorders may shed light on aspects of cellular proliferation and cellular differentiation in the acute leukemias.

Acute Disease↗
PubMed1979

Acid phosphatase in normal human blood cells: characterization by isoelectric focusing in polyacrylamide gel.

Using the high resolution technique of isoelectric focusing in polyacrylamide gel, isoenzymatic components could be discerned in acid phosphatase extracted from normal human lymphocytes, granulocytes, monocytes, and platelets. For each cell type, distinctive isoenzymatic patterns of acid phosphatase activity could be observed. These studies provide further evidence that various types of cellular differentiation are associated with differences in isoenzymatic components of acid phosphatase.

Acid Phosphatase↗
PubMed1979

Nonspecific esterases in normal human blood cells: characterization of isoenzymes by isoelectric focusing in polyacrylamide gel.

Using the high resolution technique of isoelectric focusing in polyacrylamide gel, isoenzymatic components of nonspecific esterase were resolved in esterase-rich extracts obtained from normal human monocytes, lymphocytes, granulocytes and platelets. In the case of each cell type, different isoenzymatic patterns of nonspecific esterase activity could be visualized. These studies extend the cytochemistry of nonspecific esterases by detection of previously undescribed isoenzymatic components, and suggest that the elaboration of nonspecific esterase isoenzymes may be a function of cellular differentiation.

Blood Cells↗