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Biomedical subjects

G Grossi

Publications and source records attributed to G Grossi.

At least 73 records · Page 4Linked to original sources
PubMed1989

High concentrations of catecholamines in human hypothalamic-hypophysial blood.

While the hypothalamic-hypophysial portal system has been extensively studied in laboratory animals, equivalent studies have not been performed in humans. Here, we present an experimental procedure for collecting suprapituitary blood in man. To solve the question on the origin of such blood we investigated specific markers of hypothalamic secretory activity: the catecholamines (CAs). We found (a) norepinephrine (NE), dopamine (DA), and epinephrine (E) concentrations from approximately 1.5 to 2.5, 3.5 to 4.5, and 6- to 10-fold higher, respectively, in suprapituitary than peripheral blood, (b) different NE/DA and NE/E ratios in favor of DA and E in suprapituitary blood, and (c), a complete (100%) group separation (suprapituitary vs. peripheral) when discriminant analysis included only DA and E. These data indicate that suprapituitary blood composition is different from that of the peripheral blood, and is particularly rich in CAs and claimed differences between DA and E release on one hand and NE release on the other in suprapituitary blood also are observed. We advance the hypothesis of a hypothalamic source of such amines draining via median eminence into portal vasculature, and name this blood "hypothalamic-hypophysial blood." Besides serving as "classical" neurotransmitters, CAs may also have a direct neurohormonal role in the regulation of the human hypothalamic-hypophysial function.

Adult↗
PubMed1988

Isolation and structural analysis of a ribosomal protein gene in D.melanogaster.

By using the cDNA clone containing the sequence for the L1 ribosomal protein gene of Xenopus laevis as probe (1), we have isolated positive phages from a Drosophila melanogaster genomic library. The Drosophila genomic fragment, which gives the hybridization signal with the Xenopus cDNA, was sequenced: a region of 369 bp is 70% homologous to the sequence of X. laevis L1 cDNA. The gene was localized in situ at position 98AB of the right arm of the third polytene chromosome. By S1 mapping and heteroduplex analysis we have found that the gene is interrupted by three introns. A Drosophila cDNA embryonic library was screened and three cDNA clones were isolated (900, 1400 and 1500 nt long). By Northern analysis the cDNAs identify a 1400nt transcript present at every stage of development. By the features described, the clones we have isolated identify the Drosophila rp gene homologous to the L1 rp gene of Xenopus and could code for the L1 ribosomal protein described in D. melanogaster.

Amino Acid Sequence↗
PubMed1988

Evidence for a hypothalamic alteration of catecholamine metabolism in polycystic ovary syndrome.

The role of brain catecholamine (CA) activity in the neuroendocrine regulation of the GnRH-LH system in polycystic ovary syndrome (PCO) was investigated by high-performance liquid chromatography (HPLC) with electrochemical detector. We measured urinary dopamine (DA), noradrenaline (NA), adrenaline (A), vanillylmandelic acid (VMA), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC) and total 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in a group of 12 women with PCO before and during peripheral dopa-decarboxylase blockade, by carbidopa. HVA and DOPAC concentrations were significantly lower (P less than 0.001 and P less than 0.005, respectively) in PCO patients compared with twelve control subjects in early follicular phase, whereas total MHPG concentrations and MHPG/VMA ratio were significantly higher (P less than 0.005) in PCO patients. Moreover, HVA and DOPAC concentrations in PCO patients were similar to those of the control subjects in preovulatory phase, while MHPG concentrations remained higher in PCO patients (P less than 0.01). DA, NA, A and VMA concentrations were similar to those of control subjects in both phases of the cycle. During carbidopa administration the concentrations of all urinary CAs and metabolites were unchanged, except those of DA which dropped markedly (P less than 0.001). These data suggest that (1) an altered central catecholamine metabolism consisting of DA deficiency and NA excess is present in PCO, and (2) the site of DA deficiency may be located in the hypothalamus.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Caffeine intake, fasting plasma caffeine and caffeine clearance in patients with liver diseases.

The effects of a variable daily administration of caffeine on fasting levels of caffeine in plasma and in saliva were measured in 24 patients with liver disease and hepatocellular dysfunction of variable degree. For 2 consecutive days the patients received either 250 mg of caffeine (in 2 separate doses of 125 mg each at 8:00 a.m. and at 6:00 p.m.) or a single dose of 125 mg at 6:00 p.m. Caffeine clearance was also measured and the results were correlated with the galactose elimination capacity and with antipyrine clearance. At the beginning of the study, fasting caffeine concentrations were largely variable, without any relation to liver function. A strict negative correlation between fasting caffeine and caffeine clearance was only observed after 2 days of controlled caffeine administration (rs = -0.814). Under these conditions, fasting caffeine also correlated with antipyrine clearance (rs = -0.671, n = 20) and with galactose elimination (rs = -0.565). Our data prove that fasting caffeine concentrations after an evening dose may be used as an index of liver function only in subjects under a strictly controlled dietary caffeine intake. The large availability of caffeine in the diet makes the compound scarcely reliable for a correct measurement of liver function based on a single sample, and correct clearance determination is needed.

Body Weight↗
PubMed1987

Acute alkalosis, but not acute hypocalcemia, increases panic behavior in an animal model.

Non-pretrained, randomized adult rats were tested in a panic-inducing model of passive avoidance. Intravenous treatment with alkalinizing agents (sodium lactate 0.5 M, 0.5 ml/100 g b.wt., or NaHCO3, 0.5 mEq/100 g b.wt.), but not with a hypocalcemic dose of EDTA (75 mg/kg) 3 min before testing, significantly increased panic behavior. These data may support the hypothesis that panic attacks are due to alkalosis and not to lactate-induced hypocalcemia.

Alkalosis↗
PubMed1987

Evidence for a physiological reduction in brain dopamine but not norepinephrine metabolism during the preovulatory phase in normal women.

To investigate the role of brain catecholamine (CA) activity in the mechanisms related to physiological ovulatory function, we used high-performance liquid chromatography with electrochemical detector to measure the levels of urinary dopamine (DA), norepinephrine (NE), epinephrine (E), vanillylmandelic acid (VMA), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC), and total 3-methoxy-4-hydroxy-phenylglycol (MHPG) in a group of 12 normal women during both the early follicular and pre-ovulatory phases of the menstrual cycle. The mean (+/- SEM) concentrations of HVA and DOPAC were significantly lower (P less than 0.001) during the pre-ovulatory phase than during the early follicular phase, whereas those of DA, NE, E, VMA and total MHPG were unaltered. A significant negative correlation between urinary HVA and plasma LH (r = -0.70, P less than 0.01) was also found during the pre-ovulatory period, whereas no significant negative correlations were found between urinary HVA and plasma PRL, progesterone and oestradiol. These data show: 1) reduced brain DA activity and 2) unchanged brain NE activity at the time of the midcycle surge in normal women, suggesting a physiological variation of the central DA metabolism in ovulatory function.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1987

[Evaluation of stress indicators in 2 groups of video display terminal operators].

The results of a study on 68 VDT operators are hereby presented. Various biochemical indexes are evaluated as markers of stress. In particular, urinary catecholamines and their metabolites (E, NE, DA, HVA, VMA), ACTH, cortisol, NEFA and fructosamine have been tested by the Authors. Each assay has been performed both in basal conditions, and after the completion of subjects workshift, taking into account the normal hormonal biorhythms. The data which emerged have been analyzed by statistical method ("Student t" with coupled data). Each subject data was confronted before and after workshift. The number of hours of VDT exposure and the different types of duties have been considered and evaluated. The results show that, although the data are all included within the normal range, some of the tested parameters after workshift are significantly higher, compared with the same parameters referring to the basal condition. In particular, Epinephrine and Norepinephrine seem to be the most effective markers of stress. Analogous studies will be pursued in the future by the Authors on a larger number of VDT operators.

Adrenocorticotropic Hormone↗
PubMed1985

Isolation and characterization of the human tissue-type plasminogen activator structural gene including its 5' flanking region.

mRNA specific for tissue type plasminogen activator (t-PA) is induced in HeLa cells by the tumor promoter phorbol myristate acetate (Waller, E.K., and Schleuning, W.D. (1985) J. Biol. Chem. 260, 6354-6360). To study the underlying mechanism, a cDNA library was constructed from phorbol myristate acetate stimulated HeLa cell mRNA and screened with two t-PA mRNA specific oligonucleotides (Edlund, T., Ny, T., Rånby, M., Heden, L.-O., Palm, G., Holmgren, E., and Josephson, S. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 349-352). Two nearly full length double-stranded cDNA clones were obtained. Suitable restriction fragments from the cDNA were employed as probes for the isolation of three recombinant bacteriophages, containing overlapping fragments of the t-PA gene. By restriction analysis, heteroduplex mapping, and DNA sequencing it was determined that the three overlapping fragments contain the complete t-PA structural gene and that the 2658 bases long t-PA mRNA is encoded by a gene of approximately 29 kilobases overall length, which is interrupted by 13 introns. To characterize the presumptive control region, a subcloned gene fragment, containing the 5' sequence of the cDNA, was sequenced, and the transcription initiation site was identified by nuclease S1 protection experiments. The putative transcription start site is located 24 base pairs (bp) downstream of a typical TATA consensus sequence. Two additional TATA motifs with hitherto unknown functions are found 93 and 226 bp upstream of the putative cap site. A recombinant plasmid was constructed, which accommodates the cap site including 475 bp of upstream sequences, fused to a double-stranded cDNA of t-PA mRNA which contains the complete translated and parts of the 5' and 3' untranslated regions. This plasmid directs t-PA biosynthesis in Xenopus laevis oocytes after microinjection into the germinal vesicle.

Amino Acid Sequence↗
PubMed1985

Members of the Amy-2 alpha-amylase gene family of mouse strain CE/J contain duplicated 5' termini.

Several members of the Amy-2 alpha-amylase multigene family from the CE/J strain of mouse have been cloned in cosmid vectors. Structural analysis of these recombinants reveals that the cloned Amy-2 copies contain tandem 5' termini. The duplicated 5'-terminal elements, which lie upstream from the Amy-2 cap site, are separated from their Amy-2 homologues by about 8000 bases. The orientation of these 5' orphons is the same as that of Amy-2. Gene titration and cloning experiments suggest that at least four of the approximately 15 Amy-2 copies present in the CE/J genome contain 5' orphon elements. The extent of sequence homology between 5' orphons and their gene homologues has been determined by DNA sequence analysis. All the orphons are identical and contain the entire 185 base-pairs of the first exon, 49 base-pairs of the first intron and more than 400 base-pairs of the Amy-2 5' flanking region. Intron and flanking-region sequences of the orphons differ by about 20% from their Amy-2 counterparts, and the exon by about 8%. The TATA box and the cap site are conserved, while the ATG translation initiation signal is mutated to ATA in the orphon. No transcription initiation has been detected at the orphon cap site using run-off transcription in isolated pancreatic nuclei in vitro.

Animals↗
PubMed1979

Cyst of the choroid plexus of the left lateral ventricle.

A cyst of the choroid plexus of the left ventricle is described. The cyst was lined by a choroidal epithelium and filled with cerebrospinal fluid. It produced an intermittent obstructive syndrome. The cyst was almost completely invaginated into the third ventricle, simulating an expanding process in the third ventricle. After microsurgical removal, the recovery of the patient was complete. Electronmicroscopy of the cyst wall is reported. Histological and neuroradiological features are discussed.

Brain Diseases↗
PubMed1977

Endonucleolytic cleavage of parental DNA and T4 late-gene expression: distribution analysis of single-strand and double-strand breaks.

In order to investigate the dependency of late transcription on concurrent DNA replication during bacteriophage T4 development, we analyzed the endonucleolytic cleavage kinetics of the DNA of a T4 mutant lacking DNA polymerase, DNA ligase and exonuclease by using the sucrose gradient sedimentation technique. Our results can be summarized as follows. 1. The single-strand endonucleolytic cleavage of the T4 mutant DNA is not a random process. 2. The number of single-strand nicks reaches a plateau level of 10--12 nicks/molecule. 3. The occurrence of a double-strand break is delayed and their number is at any time lower than the number of single-strand nicks. 4. The circular permutation T4 genome, as computer-simulated by the Monte Carlo method, produces a smoothing of the discrete distribution which would be expected if nicks were localized in the promoter sites of late transcription units. We conclude that our findings support the model which relates single-strand DNA nicks to the late transcription initiation sites.

Centrifugation, Density Gradient↗