Natural and Synthetic Growth Hormone Secretagogues

Ghrelin, a 28 amino acid-acylated peptide predominantly produced by the stomach, displays strong growth hormone (GH)-releasing activity. It is mediated by the hypothalamic-pituitary GH secretagogue (GHS) receptors, which are specific to a family of synthetic, orally active molecules known as GHSs. However, despite their potent and reproducible GH-releasing activity, the potential clinical use of GHSs as orally active growth-promoting agents or anabolic anti-aging drugs has not been confirmed. Ghrelin and GHSs also exert other actions mediated through central and peripheral receptors, including stimulation of adrenocorticotrophic hormone and prolactin secretion, influence on insulin secretion and glucose metabolism, orexigenic effects and modulatory activity on the neuroendocrine and metabolic response to starvation, influence on exocrine gastro-entero-pancreatic functions, cardiovascular effects and modulation of cell proliferation and apoptosis. The discovery of ghrelin and the characterization of these GH-independent biological activities has widened the knowledge of some critical aspects of neuroendocrinology and suggests possible roles for GHSs and ghrelin in the treatment of pathophysiological conditions, including those unrelated to disorders of GH secretion.     

Oxyphil parathyroid carcinomas: a clinicopathologic and immunohistochemical study of 10 cases

Oxyphil parathyroid carcinomas are uncommon neoplasms, and the clinicopathologic features of these tumors are largely unknown. We evaluated the clinicopathologic features of oxyphil parathyroid carcinomas and the expression of cytokeratin 14 (CK14), the high-affinity glucose transporter-4 (Glut-4), as well as the cell cycle proteins p27 and Ki67 and compared these with oxyphil parathyroid adenomas and chief cell parathyroid adenomas and carcinomas. Formalin-fixed, paraffin-embedded archival tissues from primary (n = 6) and recurrent (n = 4) oxyphil carcinomas were analyzed and compared with chief cell parathyroid carcinomas (n = 12), oxyphil parathyroid adenomas (n = 38), and chief cell parathyroid adenomas (n = 17) by immunohistochemistry for CK14, Glut-4, p27, and Ki67 using the avidin-biotin peroxidase system. Patients with primary oxyphil and chief cell carcinoma presented with high levels of serum calcium (n = 15.5 and 13.7 mg/dL, respectively). Approximately half the patients in each group died of disease. The Ki67 labeling index was higher (4.9 vs 1.9) and the p27 index lower (23 vs 66) in primary oxyphil carcinoma compared with primary oxyphil adenomas. CK14 was expressed in most oxyphil adenomas (35 of 38 cases) but not in oxyphil carcinomas (0 of 10 cases). Glut-4 was more commonly expressed in both groups of adenomas compared with carcinomas. These results show that oxyphil parathyroid carcinomas are functional malignancies similar to chief cell carcinomas and are associated with hypercalcemia, recurrence, and death. Expression of CK14 is very different in oxyphil adenomas compared with carcinomas. Although distinction between parathyroid adenomas and carcinomas can only be made by histopathologic and clinical findings, these results suggest that immunostaining for CK14, p27, and Ki67 may provide additional information to help distinguish between difficult cases of parathyroid adenomas and carcinomas. These findings also indicate that the same histopathologic features should be used to diagnose oxyphil and chief cell parathyroid carcinomas.     

Assessing the early luteal phase in in vitro fertilization cycles: relationships between plasma steroids, endometrial receptors, and endometrial histology

The corpus luteum-endometrial unit was investigated in in vitro fertilization (IVF) cycles using endocrine, morphologic, and biochemical measurements on the day normally scheduled for embryo transfer (day 16), in 12 stimulated and 4 natural cycles. Advanced endometrial histologic maturity was recorded in 9 of the 12 stimulated cycles. No in-phase endometria were seen when the preovulatory plasma estradiol (E2) was greater than 500 pg/ml or the day 16 plasma progesterone (P) greater than 10 ng/ml in natural or stimulated cycles. Significant negative correlations were noted between both preovulatory E2 and day 16 P and the concentration of cytosolic progesterone receptor (PRc). Advanced endometrial maturity tended to be associated with low concentrations of PRc. Regardless of endometrial maturity, the natural cycle was characterized by low cytosolic E2 receptors (ERc) and high PRc, whereas the concentration of both receptors was usually greatly reduced in stimulated cycles. It is concluded that the advanced endometrial maturation observed in stimulated IVF cycles is a consequence of the production of supraphysiologic levels of sex steroids by the corpus luteum that cause profound modifications of endometrial receptor dynamics.     

Solitary fibrous tumour of the adrenal gland associated with pregnancy

Solitary fibrous tumour (SFT), first described as a pleural lesion, has been reported in several extrathoracic sites over the past 10 years. We describe a SFT of the left adrenal gland incidentally discovered in a 23-year-old, 22-week pregnant woman and characterised by a rapid growth during the third trimester of pregnancy. Elevated serum and urinary levels of cortisol and elevated blood levels of delta 4 androstendione and 17-OH progesterone were observed. After spontaneous delivery, the patient underwent laparoscopic resectioning of the mass and of the left adrenal gland from which the tumour was apparently originating. The kidney was not involved, and no other abdominal tumours were found. Histological and immunohistochemical features were typical of SFT of pleura and other locations. Only one case of adrenal SFT is on record, and the adrenal gland is to be added to the long list of extrathoracic locations of SFT. The association with pregnancy was a previously unrecognised event in SFT. The focal expression of progesterone receptors in the tumour cells may be related to pregnancy. This observation prompted an analysis of steroid hormone receptors in SFT of classical sites (pleura). Two of five cases had focal progesterone receptors too, a finding which deserves further investigations in a much larger series of SFTs. Received: 22 December 1999 / Accepted: 22 May 2000     

Herdförmige Blasenmole der Plazenta und koexistentes,lebendes Frühgeborenes

Zusammenfassung Molenschwangerschaften mit koexistentem, lebendem Fetus sind extrem selten. H?ufig liegt eine Zwillingsgravidit?t mit sonographisch getrennten Schwangerschaften vor. Berichtet wird der Fall einer Einzelplazenta mit dem gleichzeitigen Vorliegen einer fokal in der Plazenta liegenden kompletten Blasenmole und einer komplexen Fehldifferenzierung des Restparenchyms. Diese Plazentaver?nderungen haben zu einer intrauterinen Wachstumsretardierung des Feten geführt, der in der 34. SSW hypotroph geboren wurde. Eine persistierende Trophoblasterkrankung entwickelte sich post natum nicht. Die M?glichkeiten der Entstehung von Schwangerschaften mit dem Nebeneinander von moligen Plazentaver?nderungen und lebendem Kind und deren Bedeutung werden diskutiert.      

Neuroendocrine differentiation in carcinomas of the breast: a study of 51 cases

A group of human breast carcinomas shows morphologic and histochemical evidence of neuroendocrine (NE) differentiation. This study presents a structural, immunologic, and electron microscopic analysis of 51 cases in order to establish positive criteria for identification of these tumors, their incidence, variants, and biological behavior. Argyrophilia (by the Grimelius procedure), presence of chromogranin A and/or B, and of synaptophysin are the most reliable histochemical features, correlating with the ultrastructural demonstration of dense-core secretory granules and of clear vesicles of the synaptic type. Structural features alone may be suggestive, but do not prove NE differentiation, which has to be established by additional techniques. Seven histologic types were identified, but those herein described as types A, B, and C, which show cohesive, mucoid, and mixed patterns, respectively, comprise the vast majority of the tumors. Rare NE carcinomas of the breast show structural similarities to Merkel cell and oat cell carcinomas, and behave as highly aggressive tumors. Type B (mucinous) tumors proved to be relatively indolent, while the most frequent types of endocrine tumors (types A and C) have an intermediate grade of malignancy. The analysis of a consecutive series of 100 cases of breast cancer indicates that about 8% of breast carcinomas display some degree of NE differentiation.     

Specific haplotypes of the RET proto-oncogene are over-represented in patients with sporadic papillary thyroid carcinoma

Background: Papillary thyroid carcinoma (PTC), which may be sporadic (95%) or familial (5%), has a prevalence adjusted for age in the general population of 1:100 000. Somatic rearrangements of the RET proto-oncogene are present in up to 66% of sporadic tumours, while they are rarely found in familial cases.

Purpose: In order to determine if some variants of this gene, or a combination of them, might predispose to PTC, we looked for an association of RET haplotype(s) in PTC cases and in controls from four countries matched for sex, age, and population.

Methods: Four single nucleotide polymorphisms (SNPs) across the RET coding sequence were typed and haplotype frequencies were estimated. Genotype and haplotype distributions were compared among these cases and controls.

Results: Ten haplotypes were observed, the seven most frequent of which have been previously described in sporadic Hirschsprung patients and controls. The single locus analyses suggested association of exon 2 and exon 13 SNPs with sporadic PTC. The haplotype analysis showed over-representation of one haplotype in French and Italian sporadic PTC, whereas a different haplotype was significantly under-represented in French familial PTC.

Conclusions: Our data suggest that some variants of RET and some specific haplotypes may act as low penetrance alleles in the predisposition to PTC.