Perspectives on Human Sexuality

Perspectives on Human Sexuality. Anne Bolin and Patricia Whelehan. Albany: State University of New York Press. 1999. 503 pp.     

Certain Aspects of the Sexuality of Two Species of Chlamydomonas

SUMMARY. When older cultures (18 days old) of Chlamydomonas eugametos were mated, zygote formation occurred under conditions similar to those devised for C. moewusii. Young (6 days old) cultures of the former did not mate when the nitrogen concentration of the medium was high (0.03% NH₄NO₃). In confirmation of the work of Sager and Granick, it was found that low nitrogen concentrations, produced by decreasing the concentration of NH₄NO₃ in the original medium, by increasing the intensity of the illumination, or by using old cultures, enhanced gametogenesis in C. eugametos. It has also been demonstrated that the two species are compatible with one another, even under conditions which are unfavorable for gametogenesis in C. eugametos alone.     

Paradoxical Aspects of Human Thinking

The work is devoted to study of amazing peculiarities of two different (and, in a way, mutually excluding) forms of human thinking, which are often are opposed to each other as empirical and theoretical thinking. On the example of solution of simple syllogisms, it has been shown that at different states of the left and right hemispheres of the human brain the same person gives principally different answers to the posed question. At domination of the left hemisphere, the answers turn out to be strictly formal, regardless of the real knowledge (or ignorance) of the object. At domination of the right hemisphere, the answer is based on the person's own experience rather than on formal logic. Whereas the formal-logic thinking provides for the breakthrough of the thought to new spheres of knowledge, the empirical thinking controls correspondence of the thought and reality. The integrity of the thinking activity at the combined work of both hemispheres is emphasized. The possibilities and limitations of the empirical and theoretical thinking in various spheres of the human activity are discussed from the point of view of sign systems.     

Ecological Aspects of Disease and Human Populations

This paper shows how some basic ecological themes can be illustrated,in a very explicit and quantitative way, by examples drawn fromthe interactions between human hosts and their infectious diseases.I first discuss the population biology of infectious diseases,showing how basic reproductive rates and density dependent limitationsmay be estimated. Observed cycles in the incidence of childhoodinfections are discussed as examples of Lotka-Volterra prey-predatorcycles. Trade-offs between virulence and transmissibility inthe evolution of parasite life histories are discussed in general,withthe Australian rabbit-myxoma virus story as a case study. Iconclude by mentioning ways in which the interplay between populationdensity and transmission thresholds may have influenced humanhistory.     

On Certain Aspects of Human Information Processing

Modern automated production processes have made it necessary for engineering psychology to deal with the problem of the capacity of the operator. The task of solving this problem has given rise to a special field of psychological research, called variously psychological information theory by Berlyne (8) and Infor mationspsychologie by Frank. (11)     

Temporal Aspects of the Pathophysiology of Human Ulcer Disease

In this paper, a peptic ulcer is considered from the perspective that it is representative of a heterogeneous group of multifactorial determined or influenced disorders having a common pathomorphologic expression. This heterogeneity involves several pathophysiological attributes, including both functional (including secretory and motility events and their respective driving mechanisms) and morphologic alterations that relate to mucosal resistance. Patients with duodenal ulcer (DU) have been observed to exhibit alterations, in comparison to normal subjects, in the circadian rhythm characteristics of several gastrointestinal functions. Prominent among these are altered amplitudes of several circadian-organized gastric variables, such as intragastric pH, gastrin, pepsinogen and gastric mitotic index. With respect to any given variable, a reduced group amplitude (a measure of one-half the peak-trough difference of a 24-hr rhythm) could signify an increased dispersion of acrophases (the location of the peak of a circadian rhythm along the 24-hr time scale) reflecting interindividual variation in synchronization schedules, sleep-wake patterns, or chronobiologic alterations. A reduced interindividual amplitude further supports the concept of the heterogeneity of peptic disease. A decrease in the intraindividual amplitude of certain gastric rhythms implies an altered temporal pattern over the 24 hr. This is consistent with the hypothesis of a decrease in the amount of time available for recovery of a given function or set of integrated functions, and hence, increased susceptibility to mucosal injury. Normal high-amplitude variation in gastrointestinal functioning over the 24 hr appears to be required for natural restoration of the gut.     

Temporal Aspects of the Pathophysiology of Human Ulcer Disease

In this paper, a peptic ulcer is considered from the perspective that it is representative of a heterogeneous group of multifactorial determined or influenced disorders having a common pathomorphologic expression. This heterogeneity involves several pathophysiological attributes, including both functional (including secretory and motility events and their respective driving mechanisms) and morphologic alterations that relate to mucosal resistance. Patients with duodenal ulcer (DU) have been observed to exhibit alterations, in comparison to normal subjects, in the circadian rhythm characteristics of several gastrointestinal functions. Prominent among these are altered amplitudes of several circadian-organized gastric variables, such as intragastric pH, gastrin, pepsinogen and gastric mitotic index. With respect to any given variable, a reduced group amplitude (a measure of one-half the peak-trough difference of a 24-hr rhythm) could signify an increased dispersion of acrophases (the location of the peak of a circadian rhythm along the 24-hr time scale) reflecting interindividual variation in synchronization schedules, sleep-wake patterns, or chronobiologic alterations. A reduced interindividual amplitude further supports the concept of the heterogeneity of peptic disease. A decrease in the intraindividual amplitude of certain gastric rhythms implies an altered temporal pattern over the 24 hr. This is consistent with the hypothesis of a decrease in the amount of time available for recovery of a given function or set of integrated functions, and hence, increased susceptibility to mucosal injury. Normal high-amplitude variation in gastrointestinal functioning over the 24 hr appears to be required for natural restoration of the gut.     

Dolichol in Human Brain: Regional and Developmental Aspects

Distinct regional differences in dolichol content were defined in human brain from 15 to 76 years of age. Concerning the regional distribution of dolichol, levels were: higher in cortical gray matter than in subcortical white matter, highest among cortical regions in temporal gray matter, highest among all brain regions in thalamus, and lowest among all brain regions in lower brain stem and spinal cord. The developmental changes in the contents of dolichol were found to be different among brain regions. For example, among regions with the highest levels of dolichol, in thalamus there was a six to sevenfold increase, but in parietal gray matter, only a 2.5-fold increase. Regional and developmental changes in the proportions of the individual molecular species (isoprenologues) of dolichol were also observed. The findings indicate that the metabolism of dolichol is not uniform among regions of developing and aging human brain and may have implications for the role of dolichol in normal and diseased human brain.