Biomedical subjects

P Oliveri

Publications and source records attributed to P Oliveri.

10 recordsLinked to original sources

PubMed2000

Precambrian animal diversity: putative phosphatized embryos from the Doushantuo Formation of China.

Putative fossil embryos and larvae from the Precambrian phosphorite rocks of the Doushantuo Formation in Southwest China have been examined in thin section by bright field and polarized light microscopy. Although we cannot completely exclude a nonbiological or nonmetazoan origin, we identified what appear to be modern cnidarian developmental stages, including both anthozoan planula larvae and hydrozoan embryos. Most importantly, the sections contain a variety of small (</=200 microm) structures that greatly resemble gastrula stage embryos of modern bilaterian forms.

Animals↗

PubMed2000

Homeobox genes and sea urchin development.

We describe the expression of three Paracentrotus lividus homeobox-containing genes of the dispersed class during sea urchin embryogenesis and discuss their possible roles in the mechanisms of cell specification and embryo morphogenesis. PlHbox12 represents the first regulator identified in sea urchin that belongs to the zygotic class of transcription factors. Its early and transient expression and the localization of transcripts suggests that PlHbox12 is involved in cell fate specification of the oral or aboral ectodermal territories at the early cleavage stages. PlHbox9 is expressed just after the completion of gastrulation in a narrow stripe of cells at the ectoderm-endoderm boundary. It probably organizes a novel spatial boundary which definitely separates the archenteron and the aboral ectoderm. Finally, the spatial and temporal expression of the PlOtp gene strongly indicate that this regulator is conditionally activated in few cells of the oral ectoderm and is involved in patterning of this territory at late stages. Furthermore, our data indicate that PlOtp acts upstream of signaling systems that lead to the activation of the primary mesenchyme cell gene expression program and skeletal morphogenesis.

Animals↗

PubMed1999

Spatially restricted expression of PlOtp, a Paracentrotus lividus orthopedia-related homeobox gene, is correlated with oral ectodermal patterning and skeletal morphogenesis in late-cleavage sea urchin embryos.

Several homeobox genes are expressed in the sea urchin embryo but their roles in development have yet to be elucidated. Of particular interest are homologues of homeobox genes that in mouse and Drosophila are involved in patterning the developing central nervous system (CNS). Here, we report the cloning of an orthopedia (Otp)-related gene from Paracentrotus lividus, PlOtp. Otp is a single copy zygotic gene that presents a unique and highly restricted expression pattern. Transcripts were first detected at the mid-gastrula stage in two pairs of oral ectoderm cells located in a ventrolateral position, overlying primary mesenchyme cell (PMC) clusters. Increases in both transcript abundance and the number of Otp-expressing cells were observed at prism and pluteus stages. Otp transcripts are symmetrically distributed in a few ectodermal cells of the oral field. Labelled cells were observed close to sites of active skeletal rod growth (tips of the budding oral and anal arms), and at the juxtaposition of stomodeum and foregut. Chemicals known to perturb PMC patterning along animal-vegetal and oral-aboral axes altered the pattern of Otp expression. Vegetalization by LiCl caused a shift in Otp-expressing cells toward the animal pole, adjacent to shifted PMC aggregates. Nickel treatment induced expression of the Otp gene in an increased number of ectodermal cells, which adopted a radialized pattern. Finally, ectopic expression of Otp mRNA affected patterning along the oral-aboral axis and caused skeletal abnormalities that resembled those exhibited by nickel-treated embryos. From these results, we conclude that the Otp homeodomain gene is involved in short-range cell signalling within the oral ectoderm for patterning the endoskeleton of the larva through epithelial-mesenchymal interactions.

Amino Acid Sequence↗

PubMed1999

Stable isotope techniques for the detection of Helicobacter pylori infection in clinical practice. 13C-Urea Breath Test in different experimental conditions.

The 13C-UBT has been demonstrated to be a reliable method for the evaluation of Helicobacter pylori infection. The aim of our work is to determine the cut-off point of the 13C-UBT for samples collected as gas or collected in a solution of triethanolamine. For this purpose, patients fasted for at least 6 hours were able to collect basal samples before the administration of 65 mg of 13C-urea solution. Breath samples were taken 10, 30 and 60 minutes after the administration of the labeled solution. All the samples were collected in gas collectors and in glass vials containing 1 ml of a 7% triethanolamine solution. The cut-off points for gas collected samples were established in 4.0/1000, 4.6/1000 and 4.4/1000 for 10, 30 and 60 minutes samples, respectively, while for the samples collected in triethanolamine solution, cut-off points were established in 5.0/1000, for the 10 minutes samples, in 3.5/1000 for the 30 minutes samples and 4.7/1000 for the 60 minutes samples. We found that this test has a sensitivity of 100% and a specificity of 100% for H. pylori detection in both experimental conditions, when multiple breath samples are taken. If we considered only the 30 minutes time, sensitivity and specificity diminish for the gas collected samples. We conclude that the collection of breath samples in triethanolamine solution allows a better differentiation between H. pylori infected and non infected patients than gas collected samples.

Analysis of Variance↗

PubMed1997

MIN 14C UBT: a combination of gastric basal transit and 14C-urea breath test for the detection of Helicobacter pylori infection in human beings.

The purpose of this work is to demonstrate that the 14C-urea breath test (UBT) performed at different times combined with the study of the gastric basal transit, which evaluates the intragastric displacement of a labeled solution under fasting conditions, has the advantage of being representative of the whole stomach surface and constitutes a non-aggressive test for the detection of H. pylori. This test, which has been called MIN 14C UBT, is a modification of the conventional 14C UBT in which low volumes of a solution of 14C-urea together with 99mTc-sulfur colloid are administered. The 99mTc-sulfur colloid is not absorbed in the gastrointestinal tract and has the great advantage of allowing the "visualization" of the transit of the 14C-urea within the gastrointestinal tract. This modification allows the simultaneous determination of the production of the 14CO2 and the place where this process occurs. The results show that there is a good correlation between the images obtained and the breath samples collected. We found that this test has a sensitivity of 98% and a specificity of 96% for H. pylori detection.

Breath Tests↗

PubMed1995

Homeobox-containing gene transiently expressed in a spatially restricted pattern in the early sea urchin embryo.

In the sea urchin embryo, the lineage founder cells whose polyclonal progenies will give rise to five different territories are segregated at the sixth division. To investigate the mechanisms by which the fates of embryonic cells are first established, we looked for temporal and spatial expression of homeobox genes in the very early cleavage embryos. We report evidence that PlHbox12, a paired homeobox-containing gene, is expressed in the embryo from the 4-cell stage. The abundance of the transcripts reaches its maximum when the embryo has been divided into the five polyclonal territories--namely at the 64-cell stage--and it abruptly declines at later stages of development. Blastomere dissociation experiments indicate that maximal expression of PlHbox12 is dependent on intercellular interactions, thus suggesting that signal transduction mechanisms are responsible for its transcriptional activation in the early cleavage embryo. Spatial expression of PlHbox12 was determined by whole-mount in situ hybridization. PlHbox12 transcripts in embryos at the fourth, fifth, and sixth divisions seem to be restricted to the conditionally specified ectodermal lineages. These results suggest a possible role of the PlHbox12 gene in the early events of cell specification of the presumptive ectodermal territories.

Amino Acid Sequence↗

PubMed1994

Expression of homeobox-containing genes in the sea urchin (Parancentrotus lividus) embryo.

Two homeobox-containing genes that belong to different homeodomain classes have been isolated from a sea urchin genomic library. One, PlHbox11, is the sea urchin homologue of the human and mouse Hox B3 gene, the other, PlHbox12, shows about 55% identity with paired class genes. Expression profile analysis of the two sea urchin Hbox genes suggests that they play different roles during embryogenesis. In fact, PlHbox11 transcripts are rare and are detected only in the pluteus larva and in the Aristotle's lantern and intestine of the adult. The PlHbox12 gene is, on the contrary, transiently expressed in the very early embryo already at the four cell stage; it accumulates at the 64 cell stage and disappears at later stages of development. In situ hybridization experiments to 16 and 32 cell stage whole mount embryos showed localization of the PlHbox12 mRNA to part of the mesomere-macromere region of the early cleavage embryo. These observations suggest a possible role of this gene in early events of cell specification.

Amino Acid Sequence↗

PubMed1987

Sympathetic nervous system mediates urinary kallikrein excretion in conscious rats.

1. The influence of the sympathetic nervous system on urinary kallikrein excretion (UKal) was investigated in conscious rats during stress produced by inserting a silastic catheter through the urethra into the bladder. The effect of this stress on blood glucose (BG), mean arterial pressure (MAP), urinary volume (Uv), urinary sodium (UVNa), and glomerular filtration rate (GFR) was also studied. 2. In intact animals stress of 120 min duration produced a non-significant increase of MAP, a significant increase of BG and a decrease of UNa (P less than 0.001 t-test, 9 d.f.), but it did not affect Uv and GFR. In stressed rats UKal was considerably lower (52 milli Amidasic Units [mAU] per 100 g bodyweight, s.e.m. = 5, n = 6) than in control rats (170 mAU per 100 g, s.e.m. = 21, n = 5). The inhibitory effect on UKal was also observed when kallikrein was measured by the kininogenase method. 3. Adrenal medullectomy, performed 1 week before the experiment, suppressed the stress hyperglycaemia but did not affect the reduction of urinary kallikrein or the anti-natriuresis. 4. Intracerebroventricular (i.c.v.) injection of saline also had no effect in the control or in the stressed rats, while i.c.v. d-l-propranolol decreased MAP, suppressed the stress hyperglycaemia and the anti-natriuresis and stimulated UKal, without changes in Uv and GFR. Non-stressed control rats i.c.v. injected with saline excreted considerably less kallikrein than rats i.c.v. injected with d-l-propranolol (control saline: 162, s.e.m. = 14, n = 6; vs control d-l-propranolol: 559, s.e.m. = 20, n = 6). Even in stressed rats this difference was registered (stressed saline: 56, s.e.m. = 8, n = 6; vs stressed d-l-propranolol: 554 mAU per 100 g, s.e.m. = 33, n = 6). 5. Peripheral sympathectomy with 6-hydroxydopamine (6-OHDA) did not suppress the hyperglycaemic response to stress, but it stimulated UKal. Kallikrein excretion was similar in 6-OHDA stressed (534 mAU per 100 g, s.e.m. = 30, n = 6) than in 6-OHDA control rats (491 mAU per 100 g, s.e.m. = 34, n = 6). No differences were observed on UNa and GFR between control 6-OHDA treated rats and stressed 6-OHDA treated rats. 6. The present results suggest strongly that urinary kallikrein excretion is modulated by sympathetic activity. Results after central beta-adrenergic blockade and peripheral sympathectomy led to the hypothesis that normal sympathetic tone in the kidney inhibits the release of kallikrein into the urine.

Adrenal Medulla↗

PubMed1987

Effect of pindolol and propranolol on sinus node recovery time and atrioventricular conduction intervals.

In a randomized, observer-blind study, the effect of incremental doses of pindolol 0.001, 0.002, 0.003, and 0.004 mg/kg IV and propranolol 0.01, 0.02, 0.03, and 0.04 mg/kg IV on SA nodal recovery time (SNRT) and atrioventricular conduction interval (AH) was assessed in 20 patients (15 men and 5 women age range thirty to seventy-two, mean age fifty-three). AH and His bundle-to-ventricle (HV) intervals and SNRT were measured at spontaneous heart rate and at incremental atrial pacing rates (80, 100, 120, 140 bpm). Both drugs caused significant beta blockade as estimated by the percentage suppression of heart rate increment induced by 3 mcg isoproterenol administered intravenously (pindolol 67.6 +/- 5.3%, P less than 0.007; propranolol 38.6 +/- 10.6%, P less than 0.001). Propranolol significantly prolonged SNRT (P less than 0.05) and AH interval (P less than 0.05). Pindolol did not significantly affect either SNRT (P = 0.25) or AH intervals (P = 0.78). Significant effects on HV interval were not seen. Thus, in the doses tested that resulted in significant beta blockade, propranolol prolonged SA nodal recovery times and depressed AV nodal conduction while pindolol did not affect these variables.

Adult↗

PubMed1985

Technetium-99m APD compared with technetium-99m MDP as a bone scanning agent.

We have investigated the possibilities of technetium-99m-(-3-aminohydroxypropylidene)-1-1-bisphosphon ate ([99mTc]APD) as a bone scanning agent in 14 normal subjects and 28 patients. Similar studies in the same normal subjects and patients were carried out with 99mTc-methylene-bisphosphonate ([99mTc]MDP). The compounds were labeled with 99mTc by means of an electrolytical method; the free pertechnetate content was always under 1%. The [99mTc]APD T1/2 of the third component of the disappearance plasma curve in six normal subjects was 152 +/- 46 min (mean +/- s.d.), while the 24-hr whole-body retention (WBR) was 17.6% +/- 4.6. The [99mTc]MDP value of the 24-hr WBR was 28.6% +/- 3.9 (p less than 0.001). The bone/soft-tissue ratio (B/ST) was investigated in eight control subjects on the eleventh thoracic and the fourth lumbar vertebrae. The B/ST ratios were similar for both APD and MDP studies. In 28 patients with suspected bone metastasis or primary bone disease, bone scintigraphy was carried out; both compounds showed similar findings and the same number of positive results. In five of these patients, the lesion/normal bone ratio was determined with values of 4.6 +/- 2.0 in APD studies and 4.8 +/- 2.3 with MDP. APD was also used in 126 patients; no adverse reactions were observed. The APD dose used i.v. for bone scanning was 200-fold less than those employed by mouth per day, for the treatment of bone disease for long periods. In our experience, APD appears to be an adequate agent for bone scintigraphy.

Adolescent↗