Rare-male mating advantage: An artifact caused by differential storage conditions?

Virgin males (or females) of some species ofDrosophila, when stored singly, are known to be superior in mating to males (or females) stored in groups. This may create a spurious rare-male effect on some occasions. When no account is taken of this storage effect in an experimental setup designed to show rare-male mating advantage, bias in favor of a raremale effect may result. It is shown that merely by storing the rare males singly and the common males in groups, with males not differing in any other respect, a very strong spurious rare-male effect can be produced. Similarly, it is shown that a spurious rare-female effect is possible too. It is proposed that the very strong rare-male effect for pepperment scent as found by Dal Molin [(1979).Am. Nat. 113:951–954] is merely a result of such a bias. The relevance for natural populations of the mating advantage associated with the single housing condition is discussed. In the experiments designed to show a spurious rare-male effect, mating chambers of two different sizes were used. It is shown that sexual selection is more severe in the small chambers, for both males and females.     

Ventrolateral medullary neurons projecting to the medial preoptic/anterior hypothalamic area through the medial forebrain bundle: an electrophysiological study in the rat

Summary A total of 152 ventrolateral medullary neurons was antidromically stimulated from both the medial preoptic/anterior hypothalamic area (MPOAH) and the medial forebrain bundle (MFB) in urethane anesthetized rats. These neurons were located primarily dorsal to the lateral reticular nucleus and could be readily classified in at least two groups, type I and type II cells on the basis of electrophysiological properties. The action potentials of type I cells had a shorter duration, and their conduction velocities ranged from 0.45 to 3.1 m/s. By contrast, type II cells, most predominantly observed, were characterized by a longer duration and an unusual shape of their action potential, and the antidromic propagation into the somatodendritic complex was often blocked. The conduction velocity (mean = 0.21 m/s) and absolute refractory period (mean = 2.63 ms) of type II cells are consistent with them having fine non-myelinated axons. Injection of 6-hydroxydopamine (6-OHDA), but not 5,7-dihydroxytryptamine, directly into the MFB blocked antidromic responses of 57% of type II cells tested. The residual type II cells whose antidromic responses were not affected by 6-OHDA were located significantly rostral to the 6-OHDA sensitive cells. Neither antidromic response of type I cells tested, on the other hand, was affected by 6-OHDA. The majority of type I cells were dramatically activated by noxious pinches of the tail, whereas the noxious stimuli produced no detectable change in the firing of type II cells. These data demonstrate that ventrolateral medullary neurons projecting to the MPOAH through the MFB are comprised of at least three distinct populations: 6-OHDA resistant fast conducting cells with somatic afferents, 6-OHDA sensitive and resistant slow conducting cells.     

Development of the retinal pathway to the pretectum of the cat

The development of retinal projections to the pretectal complex of prenatal and early postnatal cats has been examined using the anterograde transport of horseradish peroxidase and tritiated amino acids. As early as embryonic day 38, the entire dorsal pretectum is penetrated by retinal ganglion cell axons. At this stage the bilateral complement of retinal efferents appears to be dispersed uniformly within the pretectal anlage. A week later, on embryonic day 46, indistinct foci of peroxidase reaction product can be discerned within 2 of the primordial nuclei: the nucleus of the optic tract and the olivary nucleus. By embryonic day 56, five distinct bilateral fields of retinal fiber termination are apparent within the following regions:

(i) the nucleus of the optic tract;

(ii) the pretectal olivary nucleus;

(iii) the posterior pretectal nucleus;

(iv) the anterior pretectal nucleus; and

(v) the medial pretectal nucleus. Four days before birth, on embryonic day 61, crossed and uncrossed retinal arbors are partially segregated within the nucleus of the optic tract and the pretectal olivary nucleus.

The early postnatal retinal connection to the pretectum has an overall pattern virtually indistinguishable from that of the mature cat. The ontogeny of the retinal influx to the pretectum is similar to that of the retinocollicular projection.⁶¹ However, the development of retinal projections to the pretectum and superior colliculus appears to lag behind those to the dorsal lateral geniculate nucleus.⁴⁹ These differences may reflect temporal and spatial gradients in the maturation of three major classes of retinal ganglion cells.     

骨间前血管腕背支骨膜瓣移位修复骨不连的临床应用

报道用骨间前血管腕背支骨膜瓣移位修复骨不连、骨坏死的手术方法及疗效。方法：根据应用解剖学研究，设计以骨间前动脉腕背支为蒂的骨膜瓣，顺行移位修复尺、桡骨骨不连，逆行移位修复手舟骨、月骨不连与骨坏死。结果：临床应用19例，随访1年，在术后3～6月均达到骨愈合和骨坏死修复，关节活动功能明显改善。结论：骨间前血管腕背支为蒂的骨膜瓣移位术适合邻近骨不连、骨坏死修复。     

Supradiaphragmatic ectopic adrenocorticotropic hormone-secreting adenoma

A 22-year-old woman with Cushing's syndrome, caused by an extremely rare suprasellar ectopic pituitary adenoma, is presented. Magnetic resonance imaging and computed tomography revealed a well-circumscribed mass in the right suprasellar region. Endocrinological tests showed elevated s-adrenocorticotropic hormone level and hypercortisolemia. The tumor was totally removed by right subfrontal approach. At the time of the operation, the tumor was in continuity with the distal pituitary stalk but not with the pituitary gland. The diaphragma sellae was intact. Histologic diagnosis of the tumor specimen was confirmed as a pituitary adenoma. After surgical removal of the tumor, continued improvement in the patient's laboratory results and disappearance of her endocrine symptoms strongly indicated the absence of adenoma cells in the pituitary gland or stalk. Six years post-surgery, there was no evidence of recurrence in the patient's clinical and laboratory examination. This tumor probably originated from aberrant anterior pituitary cells of the pituitary stalk.     

Hypothalamic laterality in regulating gonadotropic function: unilateral hypothalamic lesion and ovarian compensatory hypertrophy

Regardless of the side of hemiovariectomy, unilateral lesion placed in the right-side medial anterior hypothalamus suppressed ovarian compensatory hypertrophy, but the lesion made in the left side failed to suppress it. This suggests the presence of a hypothalamic laterality in regulating gonadotropin secretion.     

HLA antigens in uveitis

HLA antigens are associated with a number of inflammatory eye diseases, most notably HLA B2 with anterior uveitis (AU). This association varies between different populations and ethnic groups. The aim of this study was to investigate the relationship between uveitis and HLA A, B and DR locus antigens in an Australian population. Seventy-two consecutive patients with uveitis were studied (37 males and 35 females) over a 6 month period. Thirty-two percent of the AU patients were HLA B27+, as were 42% of males (19% females) with their first attack of AU compared with 60% of males (23% females) with recurrent AU. The only significant difference in etiology between males and females was the greatly increased incidence of rheumatic diseases in males, in whom 77% (10/13) had radiological evidence of sacroiliitis. Additional findings included a lack of association between the HLA B7 cross reactive group and DR locus antigens in AU as well as the lack of any HLA associations in the 13 patients with posterior uveitis (PU).     

The hippocampus and neurotransplantation

The present article is a review of our own results from histological and electron microscopic studies of hippocampal neurotransplants with different levels of integration with recipient brains. A model providing complete isolation from the brain was obtained using transplants developing in the anterior chamber of the eye. The growth, development, and cytological composition of transplanted tissue was found to depend on factors such as the age of the donor embryo tissue, the genetic compatibility between the donor and recipient, and the level of integration with the brain. Ultrastructural analysis of intraocular and intracortical transplants showed that overall, nerve and glial cells have the characteristics of highly differentiated, mature elements; the numerical density and structures of synaptic contacts were similar to those in normal conditions. However, transplanted tissues contained morphological features providing evidence of continuing growth of several nerve processes and increases in non-synaptic and transport-metabolic intercellular interactions. The ultrastructural deviations observed here are regarded as the manifestations of compensatory-adaptive changes during the development of tissues in conditions deficient in natural afferent synaptic influences. It is also demonstrated that the axons of transplanted neurons lacking adequate cellular targets can establish functional synaptic contacts with neuronal elements in the recipient brain which are not their normal targets.Translated from Zhurnal Vysshei Nervnoi Deyatelnosti, Vol. 54, No. 2, pp. 149–162, March–April, 2004.