Sexual difference

Table 3.6. The dying out of 66 saline-treated male rats with differing sexual activities. Data taken from Knoll (1988)...

Experiments using individuals in different sexual and molting states have eliminated textural cues such as a soft postmolt cuticle or visual cues in sex attraction and recognition. For example, Bauer (1979 // sitchensis) and Caskey and Bauer (2005 P. pugio) performed experiments in which males showed no mating response toward recently molted (soft) males and only a slight or no response to recently molted nonparturial females. Copulatory response was elicited only by newly molted females and only upon antennal or pereopod contact by the male. 

Payne, A. P. 1979a. Attractant properties of the Harderian gland and its products on male golden hamster of differing sexual experience. J. Endocr., 80, 69—70. 

Glassification of Substance-Related Disorders. The DSM-IV classification system (1) divides substance-related disorders into two categories (/) substance use disorders, ie, abuse and dependence and (2) substance-induced disorders, intoxication, withdrawal, delirium, persisting dementia, persisting amnestic disorder, psychotic disorder, mood disorder, anxiety disorder, sexual dysfunction, and sleep disorder. The different classes of substances addressed herein are alcohol, amphetamines, caffeine, caimabis, cocaine, hallucinogens, inhalants, nicotine, opioids, phencyclidine, sedatives, hypnotics or anxiolytics, polysubstance, and others. On the basis of their significant socioeconomic impact, alcohol, nicotine, cocaine, and opioids have been selected for discussion herein. 

Malaria. Malaria infection occurs in over 30% of the world s population and almost exclusively in developing countries. Approximately 150 X 10 cases occur each year, with one million deaths occurring in African children (87). The majority of the disease in humans is caused by four different species of the malarial parasite. Vaccine development is problematic for several reasons. First, the parasites have a complex life cycle. They are spread by insect vectors and go through different stages and forms (intercellular and extracellular sexual and asexual) as they grow in the blood and tissues (primarily fiver) of their human hosts. In addition, malaria is difficult to grow in large quantities outside the natural host (88). Despite these difficulties, vaccine development has been pursued for many years. An overview of the state of the art is available (89). 

Female sexual development and behaviour in mammals occurs by default and requires no ovarian secretion, and it is only in genetic males that the testis can secrete hormones which destroy this female pattern and superimpose that of the male. Sexual differentiation is not so well defined in fish, and larval exposure to both synthetic estrogens and androgens is widely used in aquaculture to produce monosex cultures. Endocrine disruption of sexual differentiation in fish may therefore reflect both the complexity and diversity of such processes between different species. Some care is required in use of the terms hermaphrodite and sex-reversal since a true hermaphrodite has both functional testes and ovaries and a sex-reversed fish is fully functional as its final sex—both produce the appropriate viable gametes. Such functional sex-reversal is not possible in mammals, but in some species of fish it is the normal developmental pattern. In most of the cases of hermaphroditism or sex-reversal reported in the non-scientific press, there is evidence only for a few ovarian follicles within a functional testis. This may be considered as feminisation or a form of intersex, and is very clearly endocrine disruption, but it is certainly neither sex-reversal nor hermaphroditism. In some cases the terms have even been used to infer induction of a single female characteristic such as production of yolk-protein by males. 

The mammalian and avian immune systems function similarly both incorporate humoral and cell-mediated cytotoxic mechanisms, " and are thought to share a 160m year old relationship with the reptilian immune system. The immune system of mammals shows sexual dimorphism " a greater immune response is normally observed in females, which has been attributed to differences in steroid hormone concentration. In the toad Bufo regularis, sexual dimorphism of the immune system is also apparent. ... 

Individuals, regardless of gender, race, sexual orientation or socio-economic level, seek mentors for many of the same reasons. This may be for resources, visibility, enhanced skill, and counsel. However, each individual or mentee brings different expectations. Successful mentors assess where a mentee is, not where the mentee should be. The mentor provides ample opportunity for expectation discussions to take place, which in turn will guide and enrich the experience. 

Liney, K.E., Jobling, S., and Shears, J. A. et al. (2005). Assessing the sensitivity of different life stages for sexual disruption in roach Rutilus rutilus) exposed to effluents from wastewater treatment works. Environmental Health Perspectives 113, 1299-1307. 

Those authors also demonstrated that neither sexual stage nor age of plant had any effect on the qualitative composition of the lipid fractions. They did comment, however, on the possibility that the secondary chemical output of plants at these different sites might reflect local environmental conditions, especially considering that the distance between the sites at Castelluccio and Brucoli is only a few kilometers. They pointed to the work of Howard et al. (1980), who had demonstrated such effects on the chemical content of two species of Laurencia in California over... 

Metabolic differences betw een humans and other animals may account for some of the interspecies differences in specific organ toxicity of trichloroethylene (see below). Among humans, sexual differences due mainly to the effects of body fat content on trichloroethylene absorption are expected based on PBPK modeling (see Section 2.3.5). 

Hormonal influences may be limited to sexually relevant cues, since not all scent marks are socially relevant in all situations (Petrulis et al., 1995 and 1997). Chemoinvestigation by male hamsters of the female-indicator compound DMDS was independent of T. and did not differ from that of females. In contrast, the frequency of chemoinvestigation by castrates to vaginal secretion (containing DMDS) was enhanced by T. intact males investigated FHVS five times more than they do the females. 

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