PubMed Health⌕ Search

Biomedical subjects

K Jaffe

Publications and source records attributed to K Jaffe.

36 records · Page 2Linked to original sources
PubMed1990

Amino acids and memory consolidation in the cricket. I: Changes in the titer of free amino acids in nervous tissue after learning.

The involvement of certain amino acids in the memory consolidation process was investigated in the cricket Pteronemobius sp. Thirsty crickets were trained to constantly turn to one side of a symmetrical Y-shaped maze using reinforcement with water. Controls were trained to turn to both sides of the maze according to a random program. Animals were sacrificed immediately after training and free amino acid fractions were isolated from whole brain, subesophagic, prothoracic, mesothoracic and metathoracic ganglia homogenates and analyzed by high pressure liquid chromatography. A complex pattern of variation in the titer of amino acids emerged after learning, where the changes differed among the various ganglia. The most conspicuous change was an increase in the levels of urea and an amino acid-like compound related to the urea cycle, in all ganglia except the subesophagic one, if compared to controls. Arginine increased in the subesophagic ganglion, but decreased significantly in the metathoracic ganglion. The variation of ganglionic amino acid levels and its possible relation to mnemonic processes is discussed.

Amino Acids↗
PubMed1990

Amino acids and memory consolidation in the cricket. II: Effect of injected amino acids and opioids on memory.

The effect of injections of selected amino acids on memory, given before a maze-learning, was investigated. Thirsty crickets (Pteronemobius sp.) were trained to turn only to one side of a symmetrical Y-shaped maze using reinforcements with water. The insects retained the learned task 24 hr later. N2 anoxia applied immediately after training produced retrograde amnesia. Injections of Ala, Arg, Gln or morphine prior to training blocked the amnesic action of anoxia, whereas those of Cys, Met, Pro, Orn, octopamine or naloxone did not. Naloxone blocked long-term memory formation, but not learning, whereas Pro and Orn blocked both. The antiamnesic effect of morphine and Arg, but not that of Ala, was blocked by naloxone. A hypothesis assigning a neuromodulatory role to some amino acids is put forward.

Amino Acids↗
PubMed1989

Epithelioid hemangioendothelioma of the skin and femur.

A case of epithelioid hemangioendothelioma presenting as violaceous nodules on the skin of the thigh is described. On histologic examination the tumor exhibited a proliferation of vascular channels lined by plump cuboidal and atypical endothelial cells with an epithelioid appearance. Lesions of epithelioid hemangioendothelioma were subsequently discovered in the adjacent femur. These tumors were successfully treated with chemotherapy and irradiation followed by a limb salvage procedure. To our knowledge, cutaneous presentation of this rare tumor has not been reported previously.

Adult↗
PubMed1989

Comparative study of brain morphology in ants.

Brain morphology, with special attention to the three dimensional form of the corpora pedunculata, was studied in thirteen species of ants, representing four subfamilies of Formicidae. The results can be summarized as follows. (1) The neural systems processing optic and olfactory information differ in the evolutionary history among the studied taxa. A positive correlation can be demonstrated in the phylogenetic history of the corpora pedunculata, central body, cerebral bridge and olfactory lobe, but not the optic lobe. Ant species with very large eyes and thus, probably, highly developed vision, show gigantic optic lobes, with no exaggeration of any other brain structure. (2) More social species have more complex chemical communication systems and better developed corpora pedunculata (more surface in foldings of the calyces) and olfactory lobes; however, this tendency seems to reverse in highly social species with a sophisticated polymorphic caste system: individuals of these species are generally less developed neurally. (3) There are differences between the form of the internal and external calyces of the corpora pedunculata, and these differences are proportionately more pronounced in species with complex social organization. (4) Individuals from different worker castes of the same species differ in their brain morphology, but each species shows a different pattern of variation among their castes. (5) Brain structure shows characteristic marks due to the different phylogenetic developments in the taxa studied. For example the trends in brain volume-body size ratio are different for the various subfamilies, suggesting a divergent phylogenetic history.

Animals↗
PubMed1985

Black thyroid: clinical manifestations, ultrastructural findings, and possible mechanisms.

Ultrastructural examination of three black thyroid glands showed lysosomal accumulations of lipofuscin-like pigment and granular electron-dense material in association with 1) a minocycline-associated black thyroid with normal thyroid function; 2) a minocycline-associated black thyroid with a significant inflammatory component, fibrosis, and primary hypothyroidism; and 3) a black thyroid gland with no exposure to minocycline. The deposition of the pigments in the three cases resulted in macroscopically recognizable black thyroid glands. It is speculated that an imbalance in lysosomal function accounts for this abnormality. The glandular hypofunction documented in case 2 is unique and confirms the need to monitor function carefully in patients who are receiving minocycline. In one case electrondense deposits were identified in the thyroid gland interstitium.

Adult↗
PubMed1984

Opiate receptor in praying mantis: effect of morphine and naloxone.

A praying mantis displays a "frightening reaction" called deimatic reaction (DR), any time that it is faced with a patterned visual stimulus that represents a potential damage for the insect. Results of the present paper show that the DR could be also elicited by an actual noxious (an electrical shock) and that this response is similar to that elicited by a potential nociceptive stimulus (a patterned visual stimulus). The DR elicited by the electric shock was used as a model for studying the analgesic effect of opiates. The mantis was placed in an apparatus that allowed us to give the insect an electrical shock and to measure the strength of its DR. During a first session the voltage threshold necessary to induce a full DR was determined, and then, the insect was injected with a certain solution. The voltage threshold was tested one, two and four hours after injection. Mantises that were injected with only distilled water showed no changes in their voltage threshold during the three tests. Injections of 300, 350 and 400 micrograms/g of morphine-HCl increased the voltage threshold in both a time-dependent and a dose related manner. A dose of 350 micrograms/g of morphine-HCl produced 50% of response inhibition after two hours of injections and is referred to as the median antinoxious dose ( AD50 ). Sixteen micrograms/g of naloxone given in conjunction with an AD50 of morphine, partially blocked the effect of morphine during the first hour and fully blocked it during the second hour. Thirty-two micrograms/g of naloxone fully blocked the morphine effect during the first and the second hour. However, more than 48 micrograms/g of naloxone alone also increased the voltage threshold in insects, similar to those described for vertebrates.

Animals↗
PubMed1980

Research criteria for the diagnosis of depression.

Four sets of research criteria for depression are compared: the Feighner, Spitzer, Texas Actuarial, and Composite methods. Of 80 carefully selected depressed patients, 68% satisfied Feighner's criteria, 71% Spitzer's, 75% the Texas Actuarial, and 94% the Composite criteria. Not only did the criteria sets select different proportions of the total, but they also selected substantially different patients, suggesting that results obtained from studies using one set of criteria for diagnosis or selection might not be generalizable to other groups of "depressed" patients. The authors recommend further studies, comparing relative validity as well as reliability, of alternative research diagnostic criteria.

Adolescent↗
PubMedDate not supplied

Evidence favoring sperm selection over sperm competition in the interaction between human seminal plasma and sperm motility in vitro.

The effect on sperm motility of sperm-sperm and sperm-seminal plasma interactions was studied among homologous and heterologous sperm. There were no significant interactions between sperm in vitro, but it was found that seminal plasmas of different donors have different effects on sperm motility, and different sperm react differently to the same seminal plasma. Sperm showed higher motility in a pure physiological solution than when mixed with seminal plasma, even if the plasma and sperm came from the same donor. Various plasma components are responsible for this modulation of sperm motility. It would appear that large numbers of sperm are adaptive, among other things, because they are involved in sperm selection.

Adolescent↗
PubMedDate not supplied

Sex ratio at birth deviations in modern Venezuela: the Trivers-Willard effect.

This study evaluates the impact of the Trivers-Willard (T-W) effect on human populations, using demographic data collected from vital registration data in Venezuela. The evaluation of the sex ratio at birth (SRB) and of fetal and infant deaths supports the existence of T-W effect in the Venezuelan population in extreme conditions. This T-W effect was observable in the SRB but not at later ages and is related to the marital status of the mother. The results indicate that the investment in females associated with environmental adversity is greater than the investment in males associated with good environmental conditions.

Bias↗
PubMedDate not supplied

Sex differences in occupational performance.

We tested the assumption that labor organizations possess structural arrangements that may favor specific individual abilities based on neurophysiological characteristics. As some basic abilities vary between sexes, so will the occupational performance of individuals, according to the labor organization they work for. We assumed that: (1) Females possess a higher perceptual sensibility (perceptual speed and accuracy), which allows them to discriminate rapid apparition events and fine changes in the environment, in contrast to males who have a greater ability to manage spatial relationships. (2) Organizations with a functional structure require more fine perceptual abilities and these requirements are stronger at higher levels of the hierarchy. (3) Occupational performance is related to basic abilities required for a specific task, leading women to have higher occupational performance than men in labor organizations with a functional structure. By studying the technical and administrative staff of the Universidad Simón Bolivar (Venezuela), we present evidence that women have a greater capacity for perceptual discrimination; that this capacity relates to occupational performance in a labor organization with a functional structure; and that this relation is stronger at higher levels in the hierarchy. However, the extremely small sample size available for this study limits the possible generalizations of these results to other populations.

Analysis of Variance↗
PubMedDate not supplied

Medial-approach open reduction of hip dislocation in amyoplasia-type arthrogryposis.

In 95 children with amyoplasia-type arthrogryposis multiplex congenita, 40 hip dislocations in 26 patients were found. In 16 of these 26 patients, bilateral (nine patients) and unilateral (seven patients) dislocations were reduced by a medial-approach open reduction. The mean age at the time of surgery was 8.9 months. Acetabular development was satisfactory. Complications included one early redislocation, two hips with stiffness, and four of 25 hips with avascular necrosis (types 1 and 2). Overall 80% (five of seven unilateral, 15 of 18 bilateral hips) were rated good and 12% fair, and 8% (one of seven unilateral, one of 18 bilateral) were poor. Stiffness or asymmetry was not observed in the nine bilateral cases. This study suggests that dislocations in infants with amyoplasia may be successfully reduced by medial-approach open reduction. Bilateral reduction and concurrent correction of other lower limb contractures may be accomplished during the same surgical session.

Arthrogryposis↗
PubMedDate not supplied

Wave parameters of the sperm flagellum as predictors of human spermatozoa motility.

We characterized the undulatory movement of the sperm's flagellum as a sigmoid wave by measuring the absolute and linear speed of the sperm, period, amplitude and length of the flagellum's wave, and the segment comprised between the head and the origin of the movement in the flagellum. These parameters were correlated with traditional ones used to determine the pattern of movement of the sperm. Our results show that wave parameters are useful predictors of sperm motility. They correlate among themselves, and thus, a few wave parameters may characterize the sperm motility. The advantage of wave parameters is that they can be easily obtained and can be eventually associated to the sperms' internal morphology.

Automation↗
PubMedDate not supplied

Outpatient requests, initial sessions and attrition.

Treatment attrition in a psychiatric outpatient department was evaluated. Of eighty-two consecutive new patients, fifty-three (65%) showed up for a second appointment while twenty-nine (35%) failed to return. None of the demographic variables or specific categories of patient requests differentiated continuers from non-continuers; nor was attrition significantly influenced by feeling one's problems were understood, symptomatic improvement or receiving the kind of intervention originally desired. Treatment continuers were more likely to have been referred by other hospital clinics or psychiatric care facilities, and more often had previous outpatient contact, but these differences did not reach statistical significance. The only outcome measures significantly related to continuation were: perceiving one's feelings understood in the initial session, feeling satisfied with the interview, and planning to return for the next appointment. Theoretical and practical implications of these findings are discussed.

Adolescent↗
PubMedDate not supplied

Sex-linked strategies of human reproductive behavior.

We present data on fertility characteristics in the Venezuelan population for each sex separately, allowing a detailed comparative analysis of the variance in fertility between males and females. We show that the fertility distribution for both sexes is discontinuous, that the average female has a larger number of offspring per individual than the average male, and that highly fertile males outnumber highly fertile females so that the total number of offspring produced by males and females is balanced. Results indicate that a few males are responsible for a relative higher fertility of the average female and that interactions between polyandric females with monogamic and polygynic males are common. Among the Yanomami, a relatively unacculturated hunter-gatherer-horticulturist tribe, similar differences in fertility distribution of both sexes are apparent. The data suggest that human populations contain statistically distinct subpopulations, with different reproductive strategies, suggesting the existence of complex interactions among human populations which are not evident from the study of individuals or groups.

Adolescent↗