Tripeptide growth hormone secretagogues

The purpose of the present study was to compare in untreated patients suffering from moderate to severe periodontitis the efficacy of dental floss (DF) and interdental brushes (IDB) in the reduction of plaque, gingival inflammation, and probing depth in a 6-week period prior to subgingival debridement. Twenty-six patients (12 female, 14 male; mean age 37.4 years; range 27 to 72 years) were instructed to use DF for one side of the dentition and IDB for the other side as an adjunct to the daily toothbrushing for 6 weeks. Oral hygiene instructions for toothbrushing and the use of the two devices were given at baseline and at week 3. Measurements were carried out at baseline and at 6 weeks including plaque scores, probing depth, and 2 bleeding scores (periodontal pocket bleeding index and angulated bleeding index). With the IDB, the approximal plaque score at baseline of 3.09 reduced to 2.15 at 6 weeks and with DF from 3.10 to 2.47, respectively. IDB proved to remove significantly more plaque than DF. Baseline probing depth of 5.84 mm for IDB sites and 5.59 mm for DF sites was reduced to 5.01 mm at 6 weeks for both regimens. Analysis showed that the use of IDB resulted in a greater pocket reduction. Both bleeding indices were slightly reduced with IDB and DF, but no differences between devices were found. In relation to patient acceptance, more problems were observed with DF, and IDB were felt to be more efficacious. In conclusion, the results of the present study indicate that in combination with a manual toothbrush, the use of interdental brushes is more effective in removal of plaque and results in a larger reduction of probing depth than the use of dental floss. Although the differences were small, they indicate, in combination with patient preferences, that interdental brushes are to be considered preferable to floss for interdental plaque removal in patients suffering from moderate to severe periodontitis.     

Growth hormone secretagogues: focus on the growth hormone-releasing peptides

This review systematically analyses recent knowledge of the biology of the growth hormone-releasing peptides. Many years before native GHRH had been isolated and sequenced, the synthesis of an enkephalin analog, devoid of any opioid activity but capable of specifically releasing GH from in vitro pituitaries, prompted the design of a number of structurally interrelated GHRPs with improved GH-releasing activity. Nowadays, GHRPs are the most effective GH-secretagogues known and could be used profitably in humans with GH hyposecretory disturbances to promote a pattern of GH secretion that mimics physiology in a better way than the exogenously administered GH.     

Neuroendocrinology of prolonged critical illness: effects of exogenous thyrotropin-releasing hormone and its combination with growth hormone secretagogues

CENP-B is a constitutive centromere DNA-binding protein that is conserved in a number of mammalian species and in yeast. Despite this conservation, earlier cytological and indirect experimental studies have provided conflicting evidence concerning the role of this protein in mitosis. The requirement of this protein in meiosis has also not previously been described. To resolve these uncertainties, we used targeted disruption of the Cenpb gene in mouse to study the functional significance of this protein in mitosis and meiosis. Male and female Cenpb null mice have normal body weights at birth and at weaning, but these subsequently lag behind those of the heterozygous and wild-type animals. The weight and sperm content of the testes of Cenpb null mice are also significantly decreased. Otherwise, the animals appear developmentally and reproductively normal. Cytogenetic fluorescence-activated cell sorting and histological analyses of somatic and germline tissues revealed no abnormality. These results indicate that Cenpb is not essential for mitosis or meiosis, although the observed weight reduction raises the possibility that Cenpb deficiency may subtly affect some aspects of centromere assembly and function, and result in reduced rate of cell cycle progression, efficiency of microtubule capture, and/or chromosome movement. A model for a functional redundancy of this protein is presented.     

Synthesis of oligopeptide and peptidomimetic libraries

The elaboration of peptide libraries prepared by either chemical or biological methods in a format useful for discovery of peptides with specific biological activities was first introduced in the 1980s. A virtual explosion of activity in this area has occurred recently, and the basic approaches have been applied to a wide variety of chemistries and for all manner of biological, chemical and physical targets. Recent advances include new synthetic methodologies, new analytical methods, new design methods and new assay procedures.     

Cross-linked growth hormone dimers have enhanced biological activity

In this study we have investigated the effect on the bioactivity of pituitary-derived human growth hormone (hGH) and recombinant bovine (b) GH after the addition of various concentrations of the water soluble cross-linking agent 1-ethyl-3(3-dimethylaminopropyl) carbodiimide (EDC; 6.25-100 mg/ml). The biological activity of resulting cross-linked reactions were determined by its ability to promote incorporation of 35SO4(2-) into costal cartilage of hypopituitary Snell dwarf mice in vivo. Administration of EDC-treated hGH solutions resulted in a significant enhancement of hormone activity in vivo compared with non-cross-linked samples. A similar significant enhancement of bGH activity in vivo was also observed when solutions containing recombinant bGH were cross-linked using EDC. For both hGH and bGH the degree of enhancement appears to be dose-dependent for the concentration of EDC (6.25-100 mg/ml for hGH; 6.25-50 mg/ml for bGH) present in the cross-linking reactions. SDS-PAGE analysis of EDC cross-linked solutions containing hGH and bGH spiked with 125I-hGH and 125I-bGH respectively revealed that dimeric GH was the primary cross-linked component. Increasing the concentration of EDC in cross-linking reactions resulted in increased formation of dimeric hGH and bGH. There was a significant correlation between the amount of GH dimer present and the increase in biological activity, suggesting that GH dimers were responsible for the enhanced biological activity. This was confirmed by the enhanced biological activity of a purified preparation of EDC cross-linked dimeric hGH. In conclusion, covalently cross-linked GH dimers reported here have enhanced bioactivity in vivo. However, since naturally occurring GH dimers are known to have reduced biological activity, this work suggests that the structure of EDC cross-linked GH dimers differs fundamentally from that of native dimeric hGH.     

Effects of growth hormone secretagogues on prolactin release in anesthetized dwarf (dw/dw) rats

In addition to stimulating GH release, GH secretagogues such as GH-releasing peptide-6 (GHRP-6) stimulate small amounts of ACTH and PRL release. Although the effects on ACTH have recently been studied, there is little information about the effects of GHRP-6 on PRL. We have now studied GHRP-6-induced GH and PRL release and their regulation by estrogen (E2) in anesthetized male and female rats and in GH-deficient dwarf (dw/dw) rats that maintain high pituitary PRL stores and show elevated hypothalamic GH secretagogue receptor expression. Whereas GHRP-6 (0.1-2.5 microg, i.v.) did not induce PRL release in normal male or female rats, significant PRL responses were observed in dw/dw females. These responses were abolished by ovariectomy and could be strongly induced in male dw/dw rats by E2 treatment. These effects could be dissociated from GHRP-6-induced GH release in the same animals, but not from PRL release induced by TRH, which was also abolished by ovariectomy and induced in males by E2 treatment. However, the effects of GHRP-6 on PRL were unlikely to be mediated by TRH because in the same animals, TSH levels were unaffected by GHRP-6 whereas they were increased by TRH. The increased PRL response could reflect an increase in GH secretagogue receptor expression that was observed in the arcuate and ventromedial nuclei of E2-treated rats. Our results suggest that the minimal PRL-releasing activity of GHRP-6 in normal rats becomes prominent in GH-deficient female dw/dw rats and is probably exerted directly at the pituitary; these GHRP-6 actions may be modulated by E2 at both hypothalamic and pituitary sites.     

Synthesis and activities of 5-substituted-2-(p-substituted phenyl)-1-dialkylaminomethyl benzimidazole derivatives

Nine 1,2,5-trisubstituted benzimidazole derivatives were prepared and their structure have been elucidated by IR, NMR spectral data and elemental analyses. Analgesic activity of the compounds prepared was investigated in mice by modified KOSTER test. Anti-inflammatory activity of these compounds was investigated by a carregeenan-induced hind paw edema model in mice. Their antibacterial activities were examined against S. aureus, E. faecalis, E. coli, P. aeruginosa, and antifungal activity against three kinds of yeast-like fungi (C. albicans, C. parapsilosis, C. stellatoidea).     

Action of growth hormone on erythropoiesis: changes in red blood cell enzyme activities in growth-retarded patients with and without growth hormone deficiency

Fifteen red cell enzyme activities of growth-retarded patients with and without growth hormone (GH) deficiency were investigated before and after GH administration. The 15 enzymes were Hexokinase, phosphoglucomutase, glucose phosphate, isomerase, phosphofructokinase, fructose diphosphate aldolase, glyceraldehyde-3-phosphae dehydrogenase, triosephosphate isomerase, 2,3-diphosphoglycerate mutase, 3-phosphoglycerate kinase, 3-phosphoglycerate mutase, enolase, pyruvate kinase, glycose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, glutathione reducase. Sixty-six subjects were studied: 30 normal control subjects (group N) and 36 patients (aged 5-23 years) with short stature. Complete endocrine evaluation showed 21 (group I) to have GH deficiency (10 patients with isolated GH deficiency) and 15 (group II) to have normal hypothalamic and pituitary function except for two patients with a moderate hypothyroidism. Both had been receiving thyroid hormone treatment for a long time before our studies. All 36 patients were treated with 2 mg human growth hormone intramuscularly for 7 days. Before GH treatment no significant difference was observed between hematologic data in group I (GH deficiency) and group II (no GH deficiency). After GH therapy there was a significant increase in reticulocyte count in both groups of patients with short stature. The mean pretreatment value in group I was 1.294% +/- 0.084 (SEM); the mean post-treatment value was 2.081% +/- 0.287 (SEM)< P less than 0.005. The mean pretreatment value in group II was 1.0% 0.184 (SEM); the mean post-treatment value was 1.407% +/- 0.193 (SEM), P less than 0.01. In group II (no GH deficiency) mean pretreatment erythrocyte enzyme activities were not significantly different from those activities observed in normal control subjects (group N). However, in patients who lacked GH, the pretreatment activities of five red cell enzymes (glucose phosphate isomerase, triosephosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, 2,3-diphosphoglycerate mutase, 3-phosphoglycerate kinase) were significantly decreased before GH administration compared with the values in normal control subjects...     

New Gaba-containing analogues of human growth hormone-releasing hormone (1-30)-amide: I. Synthesis and in vitro biological activity

BACKGROUND AND METHODS: Congenital cystic dilatation of the bile ducts represents an uncommon anomaly of the biliary system. We report on 6 patients suffering from cystic biliary duct dilatations which were treated in our hospital between 1980 and 1992. Clinical signs included upper abdominal pain, white or clay-colored stool, icterus and/or palpable tumor. According to the classification of Todani, 4 children had type Ia cysts, 1 child a type Va cyst and 1 child a type Ia cyst with extrahepatic biliary atresia. RESULTS: Among the diagnostic methods sonography is preeminent and permitted demonstration of intra- and extrahepatic biliary duct dilatations in all of our patients. In 2 patients small cystic dilatations could be distinguished from hepatic vessels by colour-coded Doppler sonography. CONCLUSION: The treatment of choice is the resection of the dilated extrahepatic biliary ducts followed by hepaticojejunostomy using the Roux-en-Y-technique.     

Chemical synthesis and biological activities of the EGF-like domain of mouse schwannoma-derived growth factor (SDGF)

Schwannoma-derived growth factor (SDGF), an epidermal growth factor (EGF) family peptide recently discovered, has an EGF-like domain in the carboxyl terminal portion. In this study, we synthesized mSDGF(38-80) corresponding to the EGF-like domain of mouse SDGF by means of stepwise solid-phase method using Fmoc chemistry in order to evaluate the biological function of the EGF-like domain in SDGF. The linear peptide of mSDGF(38-80) was folded by direct oxidation with reduced and oxidized glutathione to form intramolecular disulfide bridges in synthetic peptide. On the biological activity, we examined mitogenic activity induced by mSDGF(38-80) in NIH/3T3 fibroblast cells and interaction with EGF receptor in A431 cells. In the results, mSDGF(38-80) was confirmed to form three disulfide linkages that were similar in pattern to EGF by amino acid and sequence analysis of fragments obtained after thermolytic digestion. However, mSDGF(38-80) possessed weak mitogenic activity in NIH/3T3 cells and weak binding affinity for the EGF receptor in A431 cells compared with those of human EGF. These results suggest that the EGF-like domain of SDGF may have little effect upon mitogenic activity and the EGF receptor binding of SDGF.     

mRNA decapping activities and their biological roles

The 5' cap structure of eukaryotic mRNAs is significant for a variety of cellular events and also serves to protect mRNAs from premature degradation. Analysis of mRNA decay in Saccharomyces cerevisiae has shown that removal of the 5' cap structure is a key step in the turnover of many yeast mRNAs, and that this decapping is carried out by Dcp1p. In addition to the yeast decapping enzyme, other activities that can cleave the 5' cap structure have been described. These include two mammalian enzymes and two viral activities that cleave cellular mRNA cap structures as part of their life cycle. Here we review these various decapping activities and discuss their biological roles.     

Short and long-term cardiovascular effects of growth hormone therapy in growth hormone deficient adults

OBJECTIVE: Since GH substitution therapy is now available for adult GH deficient patients, information on the cardiovascular effects of GH substitution has assumed major clinical interest. We have therefore assessed cardiovascular effects of short and long-term growth hormone substitution therapy in these patients. PATIENTS AND MEASUREMENTS: Doppler echocardiography was performed in 21 GH deficient patients after 4 months placebo and 4 months GH therapy, in a double blind cross-over study. In an open design study, 13 patients were reinvestigated following 16 months and 9 patients following 38 months of GH therapy. Twenty-one age and sex-matched normal control subjects were also investigated. RESULTS: Heart rate was increased in placebo treated patients as compared to controls. After 4 months of GH treatment, heart rate showed a further increase (10%, P < 0.01) and seemed to remain elevated after 16 months of GH therapy. Systolic and diastolic blood pressures were significantly lower in placebo treated patients than in controls, and did not change significantly after GH treatment. The left ventricular diastolic diameter was reduced in patients as compared to controls, but increased after 4 months GH therapy (P > 0.05) and seemed to increase further during prolonged GH treatment. Cardiac index was at the same level in controls and in placebo-treated patients, but increased by 20% following GH therapy and remained elevated after 16 and 38 months (P < 0.05) of GH substitution. CONCLUSION: Following GH substitution in GH deficient adult patients, left ventricular diastolic dimensions increased and seemed to normalize, while heart rate and cardiac output were found to be increased to supranormal levels.     

Impairment of growth hormone responsiveness to growth hormone releasing hormone and pyridostigmine in patients affected by Prader-Labhardt-Willi syndrome

In order to evaluate the impairment of GH response in patients affected by Prader-Labhardt-Willi (PLW) syndrome, in 18 patients we studied GH response to clonidine and to GHRH + pyridostigmine, a cholinergic drug which enhances GHRH induced GH responsiveness in obese patients. After clonidine GH response was abnormal in 14/18 subjects (mean GH peak: 4.1 +/- 1.3 micrograms/l; area under curve: 208.1 +/- 74.2 micrograms/l.h) while all but 5 patients showed an inadequate GH response to GHRH + pyridostigmine (mean GH peak: 13.4 +/- 2.5 micrograms/l; area under curve: 903.4 +/- 171.0 micrograms/l.h). However, in the three patients with low adiposity index, GH response to GHRH + pyridostigmine was significantly higher than that observed in fatter subjects. In addition, GH response to GHRH + pyridostigmine was negatively correlated to age and adiposity index. In conclusion, our data are consistent with the hypothesis of the existence of a complex derangement of GH neuroendocrine regulation in these subjects.     

Growth hormone releasing peptides: a comparison of the growth hormone releasing activities of GHRP-2 and GHRP-6 in rat primary pituitary cells

In the present study, the effect of GHRP-2 on GH release was evaluated in rat primary pituitary cells, and the results were compared with those elicited by GHRP-6. In the rat system, GHRP-2, like GHRP-6, acts synergistically with GRF to release GH. Co-administration of GHRP-2 and GHRP-6 at maximal concentrations had no further effect on GH release than either one alone. The GHRP's were able to desensitize cells to each other, but not to GRF. The effect of GHRP-2 was inhibited by Peptide Antagonist, but was not affected by a GRF antagonist. In conclusion, GHRP-2 was found to stimulate GH release from rat pituitary cells via the same receptor and mechanism as GHRP-6, despite the structural difference between the peptides.     

Thyroid hormone and growth hormone regulation of broiler adipocyte lipolysis

The indigenous plasmid pIJ101 is the parent of many cloning vectors used in Streptomyces. One early pIJ101 derivative, pIJ702, has been particularly widely used. pIJ702 lacks sti:cop/korB and accumulates single-stranded DNA (ssDNA). The 1.2 kb BclI-BclI sti:cop/korB and 0.7 kb SpeI-BclI sti regions were isolated from pIJ101 and cloned into pIJ702 at the PstI site in both orientations. No ssDNA was detected in constructs containing sti present in its correct orientation with respect to the basic replicon, with or without cop/korB. Constructs which contained sti in the reverse orientation did accumulate ssDNA. Thus, sti is only active as the site for second-strand synthesis in its natural orientation. Furthermore, sti inserted in either orientation into the structurally unstable pIJ702-pUC8 shuttle vectors prevented them from rearranging in S. lividans. The sti function was defined to a 0.53 kb SpeI-SacII fragment and the probable site for second-strand initiation (ssi) was identified.