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Biomedical subjects

P Colombo

Publications and source records attributed to P Colombo.

At least 19 recordsLinked to original sources
PubMed1996

cDNA sequence analysis and expression of the expression of the ribosomal protein S24 during oogenesis and embryonic development of the sea urchin Paracentrotus lividus.

A gene for the Paracentrotus lividus ribosomal protein S24, called P1-S24, has been isolated and sequenced. Ribosomal protein P1-S24 consists 130 amino acids and has a molecular weight of 14869 Da. Sequence analysis shows a high percentage (90%) identity with the corresponding gene of Strongylocentrotus purpuratus. Hybridization of the cDNA to digested sperm DNA suggests that P1-S24 is represented in no more than two copies. Studies of the temporal expression of P1-S24 gene indicate a good correlation between this and the expression of the rRNA genes both during oogenesis and embryonic development.

Amino Acid Sequence↗
PubMed1996

The human L35a ribosomal protein (RPL35A) gene is located at chromosome band 3q29-qter.

Using a polymerase chain reaction (PCR)-based strategy that distinguishes functional intron-containing genes from pseudogenes, the chromosomal location of the human intron-containing L35a ribosomal protein gene (rpL35a, HGMW-approved symbol RPL35A) was previously deduced to be onchromosome 18 using DNAs from a panel of human-rodent somatic cell hybrids. The inability to detect rpL35a in a human-hamster somatic cell hybrid containing only human chromosome 18 led to a reinvestigation of the chromosomal location of the human rpL35a gene. A clone containing intron 2 of rpL35a was isolated, sequenced, and used to isolate a P1 clone containing the human intron-containing rpL35a gene. By fluorescence in situ hybridization (FISH) analysis with the P1 clone as a probe, the rpL35a gene was located on chromosome band 3q29-qter. This location was confirmed by positive PCR analysis of a human-hamster somatic cell hybrid containing only human chromosome 3. The problem of using only human-rodent somatic cell hybrids for chromosome location is discussed.

Amino Acid Sequence↗
PubMed1996

Isolation of proteins and nucleic acids by electrophoresis on disposable gel columns.

A simple and cheap one-step method to isolate proteins or nucleic acids by electrophoresis in disposable gel columns is reported. A disposable syringe was modified to host a gel column and an elution chamber. Starting from a crude extract of E. coli, the laboratory-made devise allowed the isolation of the maltose binding protein (MBP) fused to a recombinant allergenic molecule with a molecular mass of 58 kDa, from a mixture of several proteins. Also, plasmid DNA could be isolated from a mixture containing chromosomal DNA and RNA, avoiding the use of organic solvents. Electrophoresis was performed at 150 V, 35 degrees C, pH 8.0 and 8.3 for protein and DNA, respectively. The protein or the DNA obtained showed a yield of 80% and a purity grade of 90%, as estimated by densitometry.

ATP-Binding Cassette Transporters↗
PubMed1996

Three-step immunoscintigraphy with anti-chromogranin A monoclonal antibody in tumours of the pituitary region.

In the present paper we evaluated the ability of pretargeted immunoscintigraphy (ISG) with antichromogranin A (CgA) monoclonal antibody (Mc-ab A11) in visualizing pituitary masses. The results obtained in 23 patients are described along with those of [111In]pentetreotide scintigraphy (Octreoscan) in 18 cases. Positive ISG was obtained in 9/11 (82%) non-functioning, 1/4 growth hormone-, 1/2 prolactin-, 1/2 thyrotropin-, 1/1 follicle-stimulating hormone-, 0/1 adrenocortico-trophin-secreting pituitary adenomas. In one patient with a positive ISG scan of a non-functioning pituitary adenoma, an associated neurinoma of the acoustic nerve was not imaged. The same occurred in one patient with a pituitary deposit from a mammary carcinoma and in another one with a cyst of the Rathke's pouch. Chromogranin A immunohistochemistry, carried out in 10 tumours, was positive in eight pituitary adenomas and negative in two non-adenomatous lesions. A concordant ISG occurred in all cases except for two pituitary adenomas: one cystic and necrotized and one post-operative remnant very small in size. In 18 patients with pituitary adenoma both ISG and Octreoscan were positive in 61% of cases but with a different distribution among tumours. At variance with ISG, Octreoscan visualized only 5/10 (50%) non-functioning pituitary adenomas and all (4/4) somatotropinomas. In conclusion, ISG is able to image pituitary tumours and particularly non-functioning pituitary adenomas. In this respect, it may be helpful in discriminating non-neuroendocrine masses of the pituitary region from non-functioning pituitary adenomas.

Adolescent↗
PubMed1996

[Evaluation of pathogenesis of encephalocele, high spina bifida and congenital clubfoot not forming part of any known syndrome: a case report].

The authors report the case, non forming part of any known syndrome, of a newborn with encephalocele, high cranial schisis, ocular anomalies, cleft palate and congenital clubfoot. The photographic documentation of the malformations is not possible due to a technical error in taking the photographs (lack of light in the room). Alterations to cerebral nervous tissue were histologically and cytologically characterised by immaturity and block of normal development during the early stages. For this reason the alteration of primary neuro-ectodermal tissue appears to be the initial factor with secondary involvement of anatomically and functionally contiguous fields and tissues, such as cranial bones and the eyes. The alteration of the nervous system resulted in the incapacity of the fetus to make fetal movements, making it vulnerable to extrinsic compression, above all uterine pressure. This led to the adoption of fixed postures with articular blockage most evident in the lower limbs (congenital clubfoot). The pathogenic noxa was not identified.

Anencephaly↗
PubMed1996

[Anti-c antibody neonatal hemolytic disease: a case report].

The authors present a case of neonatal hemolytic disease caused by incompatibility with the erythrocytic c antigen. The presence of this surface antigen may stimulate anti-c antibodies even in the presence of compatibility with factor D, the larger of the characters.

Antibodies↗
PubMed1995

Surf5: a gene in the tightly clustered mouse surfeit locus is highly conserved and transcribed divergently from the rpL7A (Surf3) gene.

The four previously characterized genes (Surf1 to 4) of the mouse Surfeit locus do not share any sequence homology, and the transcription of each gene alternates with respect to its neighbor(s). Adjacent Surfeit genes are separated by very small distances, and two of the genes overlap at their 3' ends. In this work we have further defined the Surfeit gene cluster by the isolation of Surf5, a fifth gene of the locus, and determination of its relationship to the other Surfeit genes. Surft5 does not share any sequence homology with the four cloned Surfeit genes. The transcription of Surf5 is divergent with respect to its neighbor the Surf3 gene, and the 5' ends of Surf5 and Surf3 are separated by only 159 bp, suggesting the presence of a second bidirectional promoter in the locus. The 3' end of Surf5 maps only 68 bp away from the processed 3' end of a pseudogene. The human and partial chicken Surf5 coding regions show greater than 95% identity, and a Caenorhabditis elegans homologue shows 38% identity and 56% similarity with the mouse Surf5 amino acid sequence. The 3.5-kb transcript of Surf5 encodes a small hydrophilic protein of 140 amino acid residues, which differs from the ribosomal protein L7a encoded by the Surf3 gene or the integral membrane protein encoded by the Surf4 gene. Subcellular fractionation located the Surf5 protein to the soluble fraction of the cytoplasm. The surfeit locus appears to represent a novel type of gene cluster in which the genes are unrelated by sequence or function; however, their organization may play a role in their gene expression.

Amino Acid Sequence↗
PubMed1995

Significance of pericardial effusion after heart transplantation.

The aim of this study was to evaluate the clinical significance of pericardial effusion after heart transplantation and to assess its correlation with acute rejection. One hundred fifty transplanted patients were followed up for the first year: serial echocardiographic studies were performed on the same day as were the endomyocardial biopsies; hemodynamic studies and coronary angiographies were performed 1 year after transplant. Ten days after surgery, pericardial effusion was absent in 77 patients, small in 52, moderate in 14, and large in 7, and was significantly related to severe postoperative bleeding (p < 0.001). Patients were classified according to the presence and the course of pericardial effusion in group A (absence or disappearance of previous pericardial effusion within 1 month, 107 patients) and in group B (onset, persistence, or increase in pericardial effusion, 43 patients). One hundred nineteen patients experienced > or = 1 acute rejection episode. The evolution of pericardial effusion was different (p < 0.0001) according to the number of acute rejection episodes and biopsy specimens showing acute rejection, histologic grading and time of the first episode, and histologic grading of the most severe acute rejection episode. Furthermore, there was a significant correlation with the cumulative duration of acute rejection episodes (p < 0.005) and the presence of previous cardiac surgical history (p < 0.007), but no correlation with cardiac transplant vasculopathy or with a positive weight mismatch. This study suggests that pericardial effusion in transplant recipients is associated with a higher incidence and more severe histologic grading of acute rejection episodes; its presence indicates the need for stricter monitoring of acute rejection.

Acute Disease↗
PubMed1995

Drug diffusion front movement is important in drug release control from swellable matrix tablets.

Swellable controlled release devices of buflomedil pyridoxalphosphate in hydroxypropyl methylcellulose were prepared, and their swelling and release behavior was investigated. The drug release as a function of time was investigated for various system parameters. Three distinct fronts were observed during the swelling and release processes, i.e., a swelling, a drug diffusion, and an erosion front. The drug diffusion front could be readily determined due to the drug's yellow color. The relative positions of the fronts and the drug release rate were studied as functions of the initial porosity and the molecular weight of the polymer carrier. It was shown that the drug diffusion front best describes the overall release behavior of the system. The fractional drug release was a strong function of the dissolved drug gel layer thickness, which separates the diffusion front from the erosion front. The effect of drug solubility was also investigated by altering the pH and the ionic strength of the dissolution medium. It was shown that as drug solubility increased, the undissolved drug gel layer thickness decreased, again showing the importance of the movement of the diffusion front in controlling the overall release.

Delayed-Action Preparations↗
PubMed1995

Iontophoresis enhances the transport of acyclovir through nude mouse skin by electrorepulsion and electroosmosis.

PURPOSE: Iontophoresis was employed for enhancing the transdermal delivery of acyclovir through nude mouse skin in vitro, with the aim of understanding the mechanisms responsible for drug transport, in order to properly set the conditions of therapeutical application. METHODS: Experiments were done in horizontal diffusion cells, using as donor a saturated solution of acyclovir at two different pH values (3.0 and 7.4). Different electrical conditions (current density and polarity) were employed. RESULTS: At pH 3.0, acyclovir anodal transport was due to electrorepulsion, since acyclovir was 20% in the protonated form. In acyclovir anodal iontophoresis at pH 7.4 the main mechanism involved was electroosmosis, since the drug was substantially unionized and the negative charge of the skin at this pH caused the electroosmotic flow to be from anode to cathode. In the case of cathodal iontophoresis at pH 3.0, acyclovir transport was enhanced approx. seven times, due to the presence of an electroosmotic contribution caused by the reversal of the charge of the skin. At pH 7.4 during cathodal iontophoresis acyclovir transport was not enhanced because the electroosmotic flow was in the opposite direction, compared to drug electric transport, i.e. anode to cathode. The increased skin permeability caused by current application was demonstrated to be less important than electrorepulsion and electroosmosis. CONCLUSIONS: Anodal iontophoresis shows potential applicability for enhancing acyclovir transport to the skin, considering that both electric transport and electroosmosis can be used by appropriately setting the pH of the donor.

Acyclovir↗
PubMed1995

Abnormalities of endocrine function in patients with clinically "silent" adrenal masses.

Because, in recent years, patients with incidentally discovered adrenal masses have been encountered increasingly, their endocrine function was investigated in basal conditions and after dynamic tests. Thirty-two patients (23 women and 9 men, aged 28-74 years) were studied. Lesion diameter, as documented by computed tomography and/or nuclear magnetic resonance imaging, ranged between 5 and 65 mm; the tumors were localized on the right in 22 patients, on the left in 5 and bilaterally in 5 cases. In basal conditions, urinary free cortisol (UFC) excretion, plasma adrenocorticotropin (ACTH) and cortisol levels were normal, except for 4 patients who showed high UFC and ACTH levels in the low-normal range. Ovine corticotropin-releasing hormone (CRH, 1 microgram/kg iv) was given to 18 patients, inducing normal ACTH and cortisol responses in 12, blunted responses in 4 and no response in 2 cases. No reduction in ACTH and cortisol levels after suppression tests was observed in 4 of 29 patients after dexamethasone (1 mg overnight) or in 6 of 29 after loperamide. The 4 patients who were unresponsive to both tests did not show any further inhibition after high-dose dexamethasone administration, had low plasma ACTH levels and showed impaired or absent responses to the CRH test: they were diagnosed as affected with preclinical Cushing's syndrome. An exogenous ACTH test performed in 30 patients caused a normal cortisol rise. Basal mean 17-hydroxy-progesterone (17-OHP) levels were not different from those in normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1995

Neuroprotective actions of 2-amino-N-(1,2-diphenylethyl)-acetamide hydrochloride (FPL 13950) in animal models of hypoxia and global ischemia.

2-Amino-N-(1,2-diphenylethyl)-acetamide hydrochloride (FPL 13950) has been demonstrated to have good anticonvulsant efficacy and a relative lack of acute side effects in rodents. Similar in structure to remacemide hydrochloride, it was also shown to possess weak potency as an uncompetitive antagonist of N-methyl-D-aspartic acid (NMDA) receptors. In our study FPL 13950 was profiled preclinically as a potential neuroprotective agent with respect to lengthening the survival time of rodents exposed to hypoxia, as well as for ability to protect the vulnerable CA1 pyramidal neurons of the rat and dog from the consequences of global ischemia. Under conditions of hypoxia, pretreatment of rodents with FPL 13950 resulted in an extension in the time to loss of the righting reflex (rats) and mortality (rats and mice). This occurred whether the rats were maintained at ambient body temperature or made hyperthermic. When administered after 30 min of four-vessel occlusion global ischemia for periods of either 7 (b.i.d.) or 14 days (s.i.d.), FPL 13950 exhibited protection of the vulnerable CA1 hippocampal neurons in rat. In the 14-day treatment study the CA3 neurons were evaluated and FPL 13950 was found to prevent the lesser degree of ischemic-induced damage to this hippocampal region. In ischemic rats treated with FPL 13950 for 7 days, electrophysiological responses of CA1 neurons (orthodromic and antidromic population spikes, in vitro) were also preserved after FPL 13950 treatment. FPL 13950 was administered i.v. at 30 min after 8 min of clamping the ascending aorta in dogs, followed by a b.i.d./s.i.d. dosing regimen for 1 wk. Neuronal damage to CA1 was considerable in the saline-treated ischemic animals but significantly protected in dogs receiving FPL 13950. FPL 13950 continues to serve as a potential backup candidate for remacemide HCl which is currently in clinical trials for patients with stroke and epilepsy.

Acetamides↗
PubMed1995

[Clinical and preclinical aspects of adrenal Cushing syndrome].

Cushing's syndrome of adrenal origin encompasses different entities: besides the occurrence of adenoma and carcinoma, a not homogeneous group includes the ACTH-independent macro- or micronodular bilateral hyperplasia and the familial pigmented nodular hyperplasia (Carney's syndrome). Moreover, isolated cases of immunological origin and food-dependence have recently described. On clinical grounds no major characteristics may help to identify the adrenal origin of Cushing's syndrome, except for few situations as carcinoma or nodular dysplasia. Laboratory investigations of patients with adrenocortical tumor are based on ACTH and cortisol determinations in basal conditions and in response to high dose dexamethasone and CRH tests. However, isolated diagnostic problems may occur, as the presence of a black adrenocortical adenoma or the uncommon persistence of a circadian rhythmicity of glucocorticoid secretion. The evaluation of new markers of bone turnover (BGP, ICTP) and of collagen turnover (PIIINP) confirms the existence of corticosteroid-induced bone and collagen damages and may also be a useful prognostic index after treatment. Although up to now food-dependent Cushing's syndrome appears to be very rare, the adrenocortical sensitivity to GIP has been investigated in patients with either pituitary Cushing's disease, or clinically silent adrenal masses. No evidence of GIP-dependent cortisol secretion during the peptide infusion or after endogenous stimulation by OGTT was observed in any case. Since the wide availability of sensitive and noninvasive imaging techniques (CT and NMR), in recent years the finding of incidentalomas has become fairly common. In patients with incidentaloma abnormalities of the endocrine function are frequently encountered, and the "preclinical" Cushing's syndrome is increasingly recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1994

cDNA cloning, expression and primary structure of Par jI, a major allergen of Parietaria judaica pollen.

A 659 bp cDNA clone** coding for an allergen of Pj pollen has been isolated from a lambda gt11 library, and its DNA sequence determined. The cDNA insert showed an open reading frame of 429 bp coding for an allergenic protein of 14,866 Da and a deduced amino acid sequence containing 143 residues. The expressed recombinant protein represented the major allergen Par jI since it reacted with 95% of the sera from Pj-allergic patients (n = 22) and with two Par jI-specific monoclonal antibodies. No similarity with other known DNA and protein sequences has been detected.

Allergens↗
PubMed1994

Lytic bone lesions suspected for metastasis: ultrasonically guided fine-needle aspiration biopsy.

Ultrasonically guided fine-needle aspiration biopsy (US-FNAB) was performed in 30 patients with a lytic bone lesions suspected for metastasis detected by conventional radiological examinations. The patients were selected for US-FNAB on the basis of the ability of the ultrasound examination to clearly visualize the lesion. The cytological diagnosis was confirmed at surgery in 3 cases, and at clinical and radiological follow-up after more than 6 months in the remaining cases. The lesions were located mostly in the thoracic skeleton (ribs and sternum) and pelvic bone. We diagnosed malignancy in 26 cases and benign lesions in 2 cases. An inadequate sample was obtained in 1 case, and 1 case yielded a false-negative result. According to these results, we obtained a sensitivity of 93%. We conclude that ultrasonically guided fine-needle aspiration biopsy is a useful technique to obtain a pathological diagnosis in cases of lytic bone lesions that can be visualized with this imaging technique.

Adenocarcinoma↗
PubMed1994

Combined use of 111In-labeled pentetreotide and three-step immunoscintigraphy with antichromogranin A monoclonal antibody in the diagnosis of pituitary adenomas.

For various pituitary adenomas, it has been demonstrated that somatostatin receptor can be present. Pilot studies have shown that radio-indium labeled pentetreotide allows very good scintigraphic localization of somatostatin receptor-bearing cell masses. Recently, the presence of CgA in pituitary adenomas has also been demonstrated. MAb A11, raised against CgA, has been successfully used with a three-step ISG for the diagnosis of neuroendocrine tumors. Therefore the combined use of three-step ISG with MAb A11 and radiolabeled somatostatin can be useful in the diagnosis of pituitary adenomas. Twelve patients, 5 secreting (group A) and 7 nonsecreting (group B) pituitary adenomas, were enrolled in the study. All patients underwent three-step ISG, and, 2 wk later, scintigraphy with 111In-labeled pentetreotide (Octreoscan). Three-step ISG consisted of i.v. injection of 1 mg of biotinylated MAb A11 (first step), followed by 10 mg of avidin (second step) and [99mTc]PnAO-biotin (third step). Tomographic imaging were acquired for three-step ISG and Octreoscan at 2 and 4 h after radiotracer injection, respectively. The results are the following: 2 patients of group A (secreting tumors) had a positive three-step ISG, whereas all the patients but one of the same group had a positive pentetreotide study; all the patients of group B (nonsecreting tumors) had a positive three-step ISG and 4 had a positive pentetreotide scintigraphy. These data suggest the utility of the combined use of these techniques for a better diagnosis of pituitary adenomas.

Adenoma↗