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Biomedical subjects

C Romano

Publications and source records attributed to C Romano.

At least 217 records · Page 12Linked to original sources
PubMed1991

Modulation of the NMDA receptor by polyamines.

Results of recent biochemical and electrophysiological studies have suggested that a recognition site for polyamines exists as part of the NMDA receptor complex. This site appears to be distinct from previously described binding sites for glutamate, glycine, Mg++,Zn++, and open-channel blockers such as MK-801. The endogenous polyamines spermine and spermidine increase the binding of open-channel blockers and increase NMDA-elicited currents in cultured neurons. These polyamines have been termed agonists at the polyamine recognition site. Studies of the effects of natural and synthetic polyamines on the binding of [3H]MK-801 and on NMDA-elicited currents in cultured neurons have led to the identification of compounds classified as partial agonists, antagonists, and inverse agonists at the polyamine recognition site. Polyamines have also been found to affect the binding of ligands to the recognition sites for glutamate and glycine. However, these effects may be mediated at a site distinct from that at which polyamines act to modulate the binding of open-channel blockers. Endogenous polyamines may modulate excitatory synaptic transmission by acting at the polyamine recognition site of the NMDA receptor. This site could represent a novel therapeutic target for the treatment of ischemia-induced neurotoxicity, epilepsy, and neurodegenerative diseases.

Animals↗
PubMed1991

Phenylketonuria missense mutations in the Mediterranean.

Two missense mutations have been identified in the phenylalanine hydroxylase (PAH) genes of an Italian phenylketonuria (PKU) patient. Both mutations occurred in exon 7 of the PAH gene, resulting in the substitution of Trp for Arg at amino acid 252 (R252W) and of Leu for Pro (P281L) at amino acid 281 of the protein. Expression vectors containing either the normal human PAH cDNA or mutant cDNAs were constructed and transfected into cultured mammalian cells. Extracts from cells transfected with either mutant construct showed negligible enzyme activity and undetectable levels of immunoreactive PAH protein as compared to the normal construct. These results are compatible with the severe classical PKU phenotype observed in this patient. Population genetic studies in the Italian population revealed that both the R252W and the P281L mutations are in linkage disequilibrium with mutant restriction fragment length polymorphism (RFLP) haplotype 1, which is the most prevalent RFLP haplotype in this population. The R252W mutation is present in 10% and the P281L mutation is present in 20% of haplotype 1 mutant chromosomes. These mutations are both very rare among other European populations, suggesting a Mediterranean origin for these mutant chromosomes.

Base Sequence↗
PubMed1991

Familial defective apo B-100, characterization of an Italian family.

Familial defective apolipoprotein (apo) B-100 is a genetic disorder presenting with hypercholesterolaemia and abnormal low-density lipoprotein (LDL) that binds poorly to LDL receptors. This disease appears to be caused by a mutation in the apo B-100 gene. In the present study thirteen members of a family with moderate hypercholesterolaemia (250-350 mg dl-1) were investigated. Biochemical studies on cultured skin fibroblasts ruled out classical familial hypercholesterolaemia (FH, receptor deficiency). We then studied the interaction between LDL and their receptors by an in vitro cell binding assay. LDL from nine affected members displayed a reduced affinity (2.5-fold) for the receptor, and were less effective than LDL from control and unaffected members in suppressing LDL receptor expression and in stimulating cholesterol esterification. LDL from the affected members had normal electrophoretic mobility, size and chemical composition. Partial delipidation did not modify the LDL binding defect. The disorder is transmitted over three generations as an autosomal codominant trait and all the affected members are heterozygotes and hypercholesterolaemics. Analysis of DNA from family members showed a point mutation leading to an Arg to Gln substitution at amino acid 3500 of the mature protein that segregated with hypercholesterolaemia and LDL defective binding. We conclude that this family is affected by familial defective apolipoprotein B-100 (FDB).

Adolescent↗
PubMed1991

A balanced complex chromosomal rearrangement (BCCR) with phenotypic effect.

The authors report on a case of balanced complex chromosomal rearrangement (BCCR) with phenotypic effect, describe the dysmorphisms and malformations observed, and discuss the various pathogenetic mechanisms. On the basis of these considerations, they underline the need for careful reporting of examined cases, distinguishing the characteristic signs from dysmorphisms that are described in several other chromosomal aberrations as well. Finally, they stress the importance of a more precise description of BCCRs for the purpose, among others, of a correct formulation of reproductive risk.

Abnormalities, Multiple↗
PubMed1991

Polyamines modulate the binding of [3H]MK-801 to the solubilized N-methyl-D-aspartate receptor.

Spermine and spermidine enhance the binding of [3H](+)-5- methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine ([3H]MK-801) to N-methyl-D-aspartate (NMDA) receptors in membranes prepared from rat brain. These polyamines also enhance binding of [3H]MK-801 to NMDA receptors that have been solubilized with deoxycholate. Other polyamines selectively antagonize this effect, a finding indicating that the polyamine recognition site retains pharmacological and structural specificity after solubilization. In the presence of spermidine, an increase in the affinity of the solubilized NMDA receptor for [3H]MK-801 is observed. However, the rates of both association and dissociation of [3H]MK-801 binding to solubilized NMDA receptors are accelerated when assays are carried out in the presence of spermidine. When kinetic data are transformed, pseudo-first-order association and first-order dissociation plots are nonlinear in the presence of spermidine, an observation indicating a complex binding mechanism. Effects of spermidine on solubilized NMDA receptors are similar to effects previously described in studies of membrane-bound receptors. The data indicate that polyamines interact with a specific recognition site that remains associated with other components of the NMDA receptor complex after detergent solubilization.

Animals↗
PubMed1991

Recurrent and reciprocal inhibition of the human monosynaptic reflex shows opposite changes following intravenous administration of acetylcarnitine.

A long-latency, long-lasting increase in the recurrent inhibitory effect on the soleus monosynaptic (Hoffmann, H) reflex was induced after intravenous administration of L-acetylcarnitine, a substance known to process central cholinergic activity. This effect was paralleled by disappearance of the H reflex inhibition (functionally disinhibition) induced by stimulation of Ia afferent fibres from the tibialis anterior (reciprocal inhibition) and gastrocnemius medialis muscle. Magnitude and time course of the L-acetylcarnitine-induced effects were significantly correlated. The data suggest that (1) the L-acetylcarnitine depression of the reciprocal inhibition is mediated by excitation of Renshaw cells impinging on Ia interneurones (INs), and (2) the inhibitory effect of GM Ia afferents onto Sol is mediated by INs subjected to Renshaw inhibition. The results point to the similarity in the wiring of the 'output stage' circuit between cat and humans, and provide a method for testing this network in man.

Acetylcarnitine↗
PubMed1991

[Conservative therapy of parenchymal renal carcinoma].

From January 1987 to October 1990, 20 patients (16 M. 4 F.) affect by localized renal cell carcinoma, underwent a conservative surgical treatment. This case study includes 8 patients with bilateral (4 synchronous-4 asynchronous), and 12 patients with unilateral renal carcinoma. In the latter group only two patients had a pathological contralateral kidney. A parenchyma sparing operation was performed electively in 10 cases and was necessary in the other 10. The tumors were found to be PT1 or pT2 in all the elective cases, except one unexpected pT3a; 1pT1, 5pT2, 1pT3a and 3pT3b in the remaining group. The follow up ranges between 1 and 36 months, two deaths in bilateral tumors cases were observed. No local recurrences have been detected up to now.

Adult↗
PubMed1991

[Risk factors for cystic kidney disease in hemodialysis patients].

Acquired bilateral cystic transformation of kidneys in patients on chronic dialysis has been increasingly noted by morphological and clinical studies. Our study aims to identify a group of high-risk patients for incidence and extent of such disease. We studied with ultrasonography 87 patients on maintenance hemodialysis (60 men and 27 women), median age 58 years (range 18 to 81), mean duration of hemodialysis 75 months (range 2-256). The presence of cysts was divided into five grades from 0 no cysts to 4 more than 15 cysts detected for each kidney. 74 patients 85% of our dialytic population had acquired cystic disease; cysts varied in size from 0.5 to 4.5 cm in diameter. The cysts were found in 97% of patients dialyzed for more than 8 years and in 73% of patients on hemodialysis for less than 3 years. The incidence of cystic disease was highly and significantly correlated with the duration of dialysis, the grade correlated with duration of chronic renal failure and hemodialysis. The extent of disease appears to be increased in males. Because of high incidence of disease in long term dialysis patients ultrasonography monitoring is recommended for patients on dialysis for more than 3 years with more attention for males.

Adolescent↗
PubMed1991

Confidentiality: a survey in a research hospital.

Despite the many justifications for protecting patient confidentiality, we recognize that confidentiality cannot be absolute. Our world of automated information and easy access and storage poses many threats to confidentiality. This paper has described a survey conducted at the NIH Clinical Center to assess the knowledge, attitudes, and behaviors of clinical physicians and nurses about confidentiality of patient information. The survey findings demonstrate the need for reminders and increased awareness about confidentiality in our setting. Most of the survey respondents had a good knowledge of what was expected of them, and they believed that confidentiality was important and maintaining it was their responsibility. Of interest was that in several simulated clinical situations, there was a discrepancy between what respondents indicated they should do and what they thought they would do. The biggest discrepancies appeared in situations that involved overhearing a patient conversation on the elevator, approaching an unfamiliar person who is reading a medical record in the nurses' station, and answering a patient's inquiry about the status of another patient. The findings support the speculation that this difference may be attributed to discomfort or decreased awareness, and not necessarily to lack of knowledge. Results indicate that policies and administrative expectations should be frequently communicated and enforced, and that educational programs that address issues of confidentiality should be provided. The results of this survey have been influential in guiding educational strategies and administrative activities at the clinical center. The clinical center initiated a confidentiality awareness campaign, displaying a new poster every three months in strategic locations and distributing other tangible reminders (such as pens, magnets, and buttons) containing the same confidentiality message.(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude of Health Personnel↗
PubMed1990

[Primary mucinous carcinoid of the ovary].

A case of primary mucinous carcinoid of the ovary observed in a 52-year-old woman is reported after some remarks on the various histogenetic theories. The observation of this extremely rare cancer was fortuitous during surgery carried out for benign pathology in the contralateral organ. Careful postoperative controls absolutely excluded the possibility of a metastatic tumour. The patient was treated by combining surgery with chemotherapy and eight months after operation is apparently free of cancer.

Carcinoid Tumor↗