Melatonin rhythms and pineal structure in a tropical bat, Anoura geoffroyi, that does not use photoperiod to regulate seasonal reproduction

Abstract: It has been hypothesized that pineal structure and function might differ between temperate zone and tropical species of mammals because of lower amplitudes of seasonal change in photoperiod and, in some areas, less seasonal climatic variation. Anoura geoffroyi produce a single offspring in November or December of each year on the Caribbean island of Trinidad, at 10°N latitude in the deep tropics. Previous work has shown that this population lacks reproductive responses to photoperiod, and must be enforcing seasonal breeding using a non-photoperiodic cue. Anoura geoffroyi have a minute, thin, and rod-like pineal gland. Throughout much of its length, the pineal courses irregularly within the ventrolateral wall of the great cerebral vein. This intimate relationship may have functional implications. Despite having a very small pineal gland, this species produced a nocturnal rise in serum melatonin. Serum melatonin levels in most individuals were below or near undetectable levels during the light period and rose to a peak averaging 100 pg/ml in the last third of the dark period. Our results indicate that, although the pineal gland of A. geoffroyi is extremely small, serum melatonin levels are comparable to those of other mammals.     

The importance of self-examination in the earliest diagnosis of multiple primary cutaneous melanomas: a report of 47 cases

BACKGROUND: Development of more than one primary melanoma in a patient is a relatively uncommon but well-recognized phenomenon. Its frequency has ranged from 1.2% to 8.2% in several series. This subgroup of patients with multiple primary lesions has not been characterized sufficiently. We report the experience of the Melanoma Unit of University Hospital Spedali Civili of Brescia, Italy. METHOD: Study subjects were drawn from 1240 patients with histologically confirmed melanoma, including melanoma in situ. From this group, multiple melanomas developed in 47 patients (3.79%). Every one of our patients has been taught to perform self-examination of the skin to detect suspicious pigmented lesions. RESULTS: Of the 47 patients described in this study, 38 had two primary melanomas, 7 had three melanomas and 2 had 5 and 10 melanomas, respectively. Mean age at first diagnosis was 46.2 years. The majority of subsequent melanomas (74.5%) were removed within 5 years of the initial operation. Synchronous lesions were found in 10 patients. In male patients, the lesion appeared most frequently on the trunk; in female patients, melanoma appeared mostly on the lower extremities. The second primary melanomas developed in the same anatomic region from the first in 53.2% of our patients. The proportion of in situ to invasive melanomas was greater for the second melanomas compared with the first melanomas. Regarding invasive melanomas, the mean thickness of the first melanomas was 1.31 mm compared with 0.66 mm for the second ones. Dividing patients into two groups, of more and less than 50, it is highlighted that in older patients synchronous lesions appear more frequently (36.4% vs. 8.0%); the median time interval between sequential melanomas is longer (84 vs. 63.7 months); and the ratio between the primary and secondary melanoma mean thickness is lower (1.21 : 1.08 vs. 1.43 : 0.63 mm). CONCLUSIONS: The study confirms that second primary melanoma is usually thinner than the first lesion, and it is more common in the same region of the body as the initial melanoma. The highest risk for a second melanoma is during the first 5 years, but a much longer time interval of 28 years is possible. Continued medical follow-up with complete skin examinations seems prudent, but it is very important to promote self-skin evaluation in patients to detect not only metastases but also subsequent primary melanomas in their earliest phases.     

Critical ovarian hyperstimulation syndrome in a coasted in-vitro fertilization patient

We report an instance of critical ovarian hyperstimulation syndrome in a highly responsive in-vitro fertilization patient despite the preventive measure of a 4 day 'coast' interval during which no gonadotrophins were administered while gonadotrophin-releasing hormone agonist therapy continued until serum oestradiol concentrations fell below 3000 pg/ml.      

Colour Doppler changes and thromboxane production after ovarian stimulation with gonadotrophin-releasing hormone agonist

The objective of this study was to evaluate the Doppler flow variations which occur following the use of different protocols of ovarian stimulation in an IVF programme, and to investigate the thromboxane production by cultured endometrial cells and its influence on embryo implantation. A total of 60 patients underwent three different ovarian stimulation protocols: long gonadotrophin-releasing hormone agonist (GnRH-a), short GnRH-a and no GnRH-a. Transvaginal ultrasonography and colour Doppler analysis were performed before and during the treatment. On the day that the Doppler examination took place, luteinizing hormone, follicle stimulating hormone, plasma oestradiol and thromboxane concentrations were assayed. On the day of oocyte retrieval, endometrial cells were collected and cultured, and their thromboxane production evaluated. No significant differences in hormonal, ultrasonographic or Doppler parameters were observed between the three groups. Ten out of 56 patients who had a successful embryo transfer became pregnant. In the group of pregnant women the pulsatility index values of both uterine and spiral arteries was lower than in non-pregnant patients, and was associated with significantly lower thromboxane concentrations from cultured endometrial cells. It is concluded that thromboxane plays a role in embryo implantation, and that Doppler flow analysis of uterine and spiral arteries in infertile patients may be important in the management of ovarian stimulation.      

CD40-mediated activation of T cells accelerates, but is not required for, encephalitogenic potential of myelin basic protein-recognizing T cells in a model of progressive experimental autoimmune encephalomyelitis

CD40 ligand-CD40 interactions are important in the development of experimental autoimmune encephalomyelitis (EAE), but it is unclear whether this interaction is critical for de novo recruitment of T cells, entry of T cells into the central nervous system (CNS), or effector function of T cells in vivo. In this report we define the role of CD40 in a model of progressive EAE that does not depend on epitope spread or recruitment of new myelin-specific T cells into the CNS. Results show that CD40 is not required for trans-migration of activated T cells through the endothelial blood-brain barrier, and in its absence T cells will both enter the CNS and induce disease. However, interaction with CD40 is critical for optimal activation and encephalitogenicity of cloned Th1 cells. In its presence, Th1 cells enter the CNS earlier and induce more severe disease. Inclusion of IL-12 during activation of Th1 cells in the absence of CD40 can override the otherwise suboptimal level of encephalitogenicity observed. The implication of these findings for therapeutic use of agents designed to block this pathway is discussed.     

Establishment of social rank among grouped male mice: relative effects on circulating FSH, LH, and corticosterone

Previously-isolated, adult, CF-1 male mice were grouped four per cage, killed after periods of time ranging from one hour to 14 days, and their plasma assayed for corticosterone, FSH and LH. Dominant and subordinate ranks were easily separable after 24 hr for comparison with each other and with isolated controls that were also killed throughout the 14-day experimental period. The one hour responses to grouping, during which all males were fighting intensely to establish rank, included a 5–6 fold increase in plasma corticosterone and concurrent depressions in circulating gonadotropins, 19% for FSH and a dramatic 94% for LH. Plasma corticosterone returned to baselevels between Days 1 and 3 in the case of dominant males and between Days 3 and 6 for subordinates. Adaptation was also observed for FSH in the plasma of dominants but later than that occurring for corticosterone. Plasma FSH in subordinates and circulating LH among both relative ranks were still depressed at the end of the 14-day period. A reciprocal relationship between adrenocortical activity and gonadotropin secretion was thus observed only during the early phases of dominance-subordination establishment; thereafter, secretory patterns for these three hormones functioned independently. Seminal vesicles were little affected by grouping but mean preputial weight increased markedly and progressively among dominant males and decreased with time in subordinates.