Biocompatible Photoinduced Alkylation of Dehydroalanine for the Synthesis of Unnatural α-Amino Acids.

A site-selective alkylation of dehydroalanine to access protected unnatural amino acids is described. The protocol is characterized by the wide nature of alkyl radicals employed, mild conditions, and functional group compatibility. This protocol is further extended to access peptides, late-stage functionalization of pharmaceuticals, and enantioenriched amino acids.

Combined aerobic and resistance training: are there additional benefits for older hypertensive adults?

OBJECTIVES:: The objective of this study was to compare the effects of a combination of aerobic and resistance training to those of isolated aerobic training on blood pressure, body composition, and insulin sensitivity in hypertensive older adults. METHOD:: Forty-four patients were randomly assigned to the aerobic group, resistance and aerobic group, and control group. Before and after 10 weeks, the following data were obtained: 24-hour ambulatory blood pressure data, abdominal circumference, waist circumference, body mass index, lean mass, fat mass, and insulin sensitivity. The study was conducted with 3 training sessions per week. RESULTS:: Comparison revealed significant reductions in the body mass index, abdominal and waist circumferences, and ambulatory blood pressure (24-hour, wakefulness and sleep systolic/diastolic blood pressures) in both the aerobic group and the resistance and aerobic (combined) group. The fat mass only changed in the combined group. There was no difference in the insulin sensitivity in any group. CONCLUSIONS:: The combined treatment and aerobic treatment alone were equally effective in reducing the blood pressure, body mass index, and abdominal and waist circumferences, although the addition of the resistance component also helped reduce the fat mass.

Cation-pi interaction in potassium-polyene complexes and the fate of potassium ion: a theoretical study.

Ab initio studies have been done at B3LYP/6-31G* level of theory to determine the structural changes on the substitution of potassium to odd-numbered all-trans conjugated polyenes ranging from C(5) to C(13). The results show that potassium is always positioned in the form of K(+) above an odd carbon other than the terminal carbons and that the stablest structural isomer is the one with K(+) lying above the central odd carbon. If a central odd carbon does not exist (as in C(11)-system), then K(+) will be positioned above the odd carbon nearest to the central carbon to achieve maximum stability. The difference in the binding energies of the isomers is generally small and it becomes insignificantly small as the carbon chain length increases so that under suitable conditions K(+) ion may be made to move between the ends of the polyene. The metal-polyene complexes are seen to have a considerably reduced HOMO-LUMO gap. Further, the interaction of potassium with the polyene not only caused a total rearrangement of the bond lengths, bond angles and dihedral angles, but also induced a bend (warping) to the polyenic fragment that pockets K(+). The structural changes and stability of the metal-polyene complexes are explained in terms of electrostatic interaction and cation-pi cloud interaction.

Bioassayable gonadotropin releasing hormone-like activity in the spent nutrient medium of rat sertoli cells in primary cultures.

Investigations were undertaken to demonstrate bioassayable GnRH-like activity in the spent nutrient medium of Sertoli Cells in Primary Cell Cultures (SCCM) using an in vitro bioassay procedure. The bioassay involved the use of intact pituitaries from day-12 male rats. Amounts of LH and FSH released into the incubation medium in response to varying doses of synthetic GnRH were measured by radio-immunoassays. SCCM was extracted with methanol and diethylether. The extracted SCCM was evaporated under a stream of nitrogen at 50 degrees C. The dry residue was re-suspended in the assay medium and centrifuged. The supernatant was used as the source of GnRH-like activity. The treated SCCM gave a dose response parallel to that given by synthetic GnRH. Boiling and trypsinization of extracted SCCM destroyed the GnRH-like activity. Addition of synthetic GnRH to different doses of extracted SCCM gave additive response.

Effect of testosterone, estradiol-17 beta, and 5 alpha-dihydrotestosterone on inhibin production by sertoli cells in culture.

Inhibin activity in charcoal-extracted spent culture medium of Sertoli cells in Primary culture (CSCCM) was monitored by following the temporal inhibition of serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in normal adult male rats. Subcutaneous injection of CSCCM reduced LH and FSH levels within 15 min and maintained the inhibition up to 10 hr. No selective suppression of FSH was observed. The model was used to assess inhibin activity in CSCCM from Sertoli cell cultures incubated with 5 alpha-dihydrotestosterone (DHT), testosterone (T), and estradiol -17 beta (E2) (5 micrograms/ml) for 24 hr. CSCCM from T and E2 treated groups suppressed gonadotropins while the group exposed to DHT failed to elicit any inhibition. DHT seems to inhibit the release of inhibin by Sertoli Cells.

Pituitary cytology of the freshwater teleost Anabas testudineus (Bloch).

In the pituitary of A. testudineus the rostral pars distalis (RPD), proximal pars distalis (PPD) and pars intermedia (PI) are arranged in a rostro-caudal axis. The rostral neurohypophysis (NH) extends dorsal to the pars distalis, while the caudal part vertically penetrates into the PI and ramifies in its component. The RPD mainly consists of erythrosinophils and PgH-positive cells which are comparable to the lactotropes and corticotropes mentioned in the literature. In the nonbreeding season, acidophils are the predominant cells of the PPD and are largely confined to its dorsal aspect. The two types of cyanophils present in the PPD could not be differentiated with the various techniques used in this study. However, those cyanophils which increase in number and are active during the spawning season may be the gonadotropes, while those which are cytologically inactive may be the thyrotropes. The pars intermedia consists of PAS+ and PhH+ cells. Trichrome and tetrachrome staining techniques revealed the presence of acidophils, cyanophils and amphiphils in the PI.

Hypothalamo-hypophysial neurosecretory and vascular system of the teleost Labeo rohita (Ham.).

The paired nucleus preopticus (NPO) lying on either side of the III ventricle gives rise to the left and right main neurosecretory tracts which proceed posteroventrally towards the pituitary and give rise to several finer axons which ramify the infundibular floor adjacent to the pituitary. The bulk of the neurosecretory tracts enter the pars intermedia and few finer ones are seen among the pars distalis. The ventromedian component of the nucleus lateralis tuberis (NLT) is aldehyde fuchsin (AF) positive whereas the anterolateral neurons are AF negative. The internal carotid artery gives rise to the hypophysial and ventral hypothalamic arteries. The ventral hypothalamic artery gives rise to the primary capillary plexus at the infundibular floor region adjacent to the pituitary stalk. Portal vessels formed from this plexus largely irrigate the adenohypophysis. The hypophysial artery enters the neurohypophysis and gives rise to typical teleostean type neuradenointerface vasculature. Morphological contact between the neurosecretory axons and primary capillary plexus at the floor of the infundibulum suggests the possibility of at least some active principles entering the blood vessels. Structurally L. rohita exhibited both tetrapodean and teleostean type of hypothalamo-hypophysial vasculature. Morphological evidences suggest a direct neuroglandular and an indirect neurovasculoglandular pathways of hypothalamic control of hypophysis in L. rohita.

Pituitary cytology of the Indian carp Labeo rohita (Ham.).

In the adenohypophysis of Labeo rohita eight cell types could be identified on the basis of their different tinctorial response to various staining techniques. The rostral pars distalis has 3 types of cells. Type 1 is stained with erythrosin, orange G, and acid fuchsin. Type 2 cells are lead hematoxylin positive and give an amphiphilic reaction in response to tri and tetrachrome techniques. Type 3 cells are stainable with PAS, ATh, AB, AF, and aniline blue and are distributed in an area comprises of anteroventral RPD and anterodorsal PPD. Apart from type 3, the PPD has two more cell types. The classical acidophils forming the type 4 cells readily take up orange G, erythrosin and acid fuchsin. Type 5 cells have affinity for PAS, ATh, AB, AF and aniline blue as that of type 3 cells, but they are relatively smaller. Pars intermedia has type 6 and 7 cells which are PbH and lightly PAS + ve respectively. Eight cell type is constituted by the chromophobes which are seen in all the components of the adenohypophysis, they might be the immature or degranulated chromophils. On the basis of colour reactions cell types 1, 2, 3, 4 and 5 of Labeo rohita are comparable to the prolactin, ACTH, TSH, STH and gonadotropin secreting cells described in other teleosts by earlier workers using comparable techniques. However, functional interpretation based on staining reactions is tentative and needs experimental verification.

Structure of the neurohypophysis and the hypothalamo-hypophysial vascularization in the teleost Channa punctatus Bloch.

In C. punctatus the median eminence includes the subterminal region of the hypothalamus and the anterior neurohypophysis. It is formed of ependymal, fibrous and reticular layers as in the tetrapods. Primary capillary plexus extends from the subterminal region to the extremity of the anterior neurohypophysis. Only few portal vessels from the hypothalamus enter in the pars distalis. All the components of pituitary including the pars intermedia are irrigated by the secondary plexus formed from the portal vessels emerging out of the anterior neurohypophysis. The neurosecretory axons and the ependymal cells are in close morphological contact with the primary plexus. Several axons have perivascular endings at the median eminence. Some axons were found to be only silver or aldehyde fuchsin positive whereas some others take up both. The silver positive axons were abundant in the pars distalis and the AF positive ones were more concentrated in the pars intermedia with greater accumulation of neurosecretory material.

Hypothalamohypophysial vascular and neurosecretory link in the teleost Bagarius bagarius (Ham.).

A three-dimensional picture of the hypothalamohypophysial neurosecretory system of B. bargarius could be obtained by adopting in situ staining techniques. The paired NPO give rise to left and right neurosecretory tracts which, although they approximate as a common tract, maintain their individuality till entering the pars intermedia. The ventral hypothalamic and the hypophysial arteries take their origin from the internal carotid artery. The former contributes to the formation of the primary plexus of the median eminence and the latter enters the pituitary directly, giving rise to the neuroadreno-interface vasculature. The vasculature of the median eminence lies in close contact with the long common neurosecretory tract. Morphological evidence suggests that in B. bagarius there are three pathways of hypothalamic control of the hypophysis: (1) A direct neuroglandular pathway, where the neurosecretory axons come directly in contact with the adrenohypophysial cells. (2) An indirect neurovasculoglandular pathway, where the blood exposed to the NSM at the median eminence comes in contact with gland cells. (3) Another indirect neurovasculoglandular pathway, where the blood is exposed to NSM at the neurohypophysis prior coming in contact with the gland cells. Thus, B. bagarius has the 'median eminence equivalent' neuroadeno-interface vasculature typical of the teleosts and the median eminence comparable to the Elasmobranchs, Holocephali and primitive Actinopterygians. This shows that the pituitary portal system of teleosts is in general agreement with that of other fish groups, except that in some it is restricted to the neuroadreno-interface, whereas in others like B. bagarius it extends to the hypothalamus also. These may be termed anterior and posterior median eminence.