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Biomedical subjects

L Guida

Publications and source records attributed to L Guida.

At least 73 records · Page 4Linked to original sources
PubMed1990

Enhancement of hypoxemia by atrial shunting in cystic fibrosis.

Patients with CF may develop hypoxemia which seems disproportionate to the degree of pulmonary disease. In a series of patients with CF and advanced pulmonary disease undergoing transesophageal echocardiography for the evaluation of cor pulmonale, eight of 15 patients were found to have atrial shunts through a stretched foramen ovale. To our knowledge, this is the first observation of intracardiac shunting in CF. This phenomenon may account for unexplained levels of cyanosis and worsening of hypoxemia with exercise, vasodilators, or PEEP and poses the threat of paradoxic emboli when central venous lines are used in these patients.

Adult↗
PubMed1990

Glyoxylic acid promotes poly(ADP-ribosyl)ation of nuclear proteins in K562 cells cultured at limiting dilution.

Addition of glyoxylic acid to the culture medium allows survival and proliferation of K562 human erythroleukemic cells cultured at low population density in the absence of serum. Concomitantly, glyoxylic acid induces a remarkable increase in nuclear poly(ADP-ribose) content, as compared to control cells cultured without addition of glyoxylate. The latter effect is reversed by addition of micromolar concentrations of benzamide to the cultures. As glyoxylic acid is metabolized through NADH-dependent reduction to glycolic acid only, the observed effects on cell growth and on nuclear poly(ADP-ribose) content seem to be mediated by an increased cellular ability to oxidize NADH.

Benzamides↗
PubMed1990

[The involvement of the oromaxillofacial area in secondary hyperparathyroidism].

The authors report a case of hyperparathyroidism arising in a woman after long-term haemodialysis treatment with very serious manifestations for the maxillary bones. The patient had already undergone an intervention of subtotal parathyroidectomy 2 years before, but there was no improvement in the clinical symptomatology and hematochemical signs. Excluding development into the third form of hyperparathyroidism, in consideration of present therapeutic orientations for the secondary form, and in view of the patients serious local and general conditions, it was decided to treat the case with medical therapy alone.

Chronic Disease↗
PubMed1990

[Neutrophil function and microbial associations in rapidly progressing periodontitis and chronic periodontitis in the adult].

Our study was focused on the functional characteristics of neutrophil leukocytes (PMN) and the subgingival microflora in two different forms of periodontal disease: 1) adult periodontitis (AP); 2) rapidly progressive periodontitis (RPP). Our study dealt with the functional characteristics of neutrophil leukocytes in the gingival fluid and in the peripheral blood. These were found markedly reduced in the RPP group, while, in the AP group, they were comparable to those of a healthy control group. No difference between local and systemic values was detected. Moreover, some samples of subgingival plaque were taken from two groups of patients, affected by AP and RPP respectively. The above samples showed a predominance of Gram-negative flora over Gram-positive flora, and of anaerobic flora over the aerobic one, and the predominance of specific pathogens in each of the two forms of periodontal disease. The subgingival plaque samples taken at the end of the periodontal treatment from five out of ten patients affected by RPP showed inverse ratios, as well as the absence of the previously detected pathogens. The findings underline the relevance of tests of leukocytes functionality and that of microbiological analysis to allow correct diagnosis of dubious forms of periodontal disease and the checking of the posttreatment results.

Adult↗
PubMed1989

Encapsulation of doxorubicin in liver-targeted erythrocytes increases the therapeutic index of the drug in a murine metastatic model.

Doxorubicin-loaded, glutaraldehyde-treated murine erythrocytes, once reinjected into circulation, are rapidly taken up by liver and lungs and behave as an organ-targeted, slow delivery system for the encapsulated drug. The antitumor activity of encapsulated doxorubicin (former generic name, adriamycin) was compared with that of the free drug in a murine hepatic and pulmonary tumor model. This was obtained by intrasplenic injection of L1210 lymphoma cells followed by splenectomy. Different schedules of treatment of tumor-bearing mice with erythrocyte-encapsulated or free doxorubicin were investigated. The optimal schedule of treatment for free doxorubicin proved to be i.v. bolus administration on the day of splenectomy. Under these conditions, the dose producing 50% inhibition of metastatic growth in the liver, as measured by inhibition of 5-[125I]iodo-2'-deoxyuridine uptake 9 days after tumor induction, was 6.3 mg/kg for free doxorubicin and 0.48 mg/kg for the encapsulated drug. In these conditions pulmonary tumor development was even more efficiently prevented by encapsulated doxorubicin as compared with the free drug. The values of the therapeutic index (TI), defined as the ratio between the maximal tolerated dose (LD10) and the minimal effective dose (ED90, producing 90% inhibition of liver metastatic growth), were 4.2 and 1.8 for encapsulated and free doxorubicin, respectively.

Alanine Transaminase↗
PubMed1989

[Orthodontic card: a compilation proposal].

In relation to particular specialist filing of orthodontic patients and with reference to the need for pointing out peculiar data during diagnosis and treatment, it is necessary to have a suitable clinical card, which, if filed, may represent a reliable and valid document for case reports. Such a card has also been conceived for its likely insertion into a computer database.

Cephalometry↗
PubMed1989

[Cranial and facial sutures: embryological aspects, anatomy and effects on orthopedic treatment].

In this work, the AA. have related the principal suture of the skull and the face, analysing the embryonal, functional and anatomic aspects, with particular reference to the times of end of growth and ossification. Furthermore, the AA. had explained the orthopedic appliances which influence, with their action, the activity of specific suture, emphasizing the growth period in which they are more efficient in the correction of the various dentofacial disharmonies.

Adolescent↗
PubMed1988

Improved metabolic properties of hexokinase-overloaded human erythrocytes.

Human erythrocytes were loaded with homogeneous hexokinase purified from human placenta (an enzyme species apparently identical to the erythrocyte enzyme), using a procedure of encapsulation based on hypotonic hemolysis, isotonic resealing and reannealing. The hexokinase-overloaded erythrocytes contained 4.77 +/- 0.75 IU of hexokinase activity per ml of packed erythrocytes, a value 15-times higher than that of corresponding unloaded or native red cells. The hexokinase-loaded erythrocytes were found to metabolize twice the amount of glucose consumed by the unloaded cells through a nearly doubled glycolytic activity, while the activity of the hexose monophosphate shunt pathway was unmodified. Estimates of glycolytic intermediates showed increased levels of most metabolites with respect to the unloaded erythrocytes, while the intracellular concentrations of adenine nucleotides and 2,3-bisphosphoglycerate were unaffected by entrapment of hexokinase. The new steady-state condition characterized by improved glycolytic function was demonstrated to be directly related to enhanced levels of hexokinase activity and not to the use of a rejuvenation solution during the procedure of entrapment. These results are consistent with suggestions by several investigators that glucose metabolism in human erythrocytes is regulated by hexokinase, and they open new perspectives for manipulating erythrocytes with the ultimate aim of improving their survival under different storage conditions.

Adenine Nucleotides↗
PubMed1988

Conversion of encapsulated 5-fluoro-2'-deoxyuridine 5'-monophosphate to the antineoplastic drug 5-fluoro-2'-deoxyuridine in human erythrocytes.

The fluoropyrimidine deoxyribonucleotide 5-fluoro-2'-deoxyuridine 5'-monophosphate (FdUMP) was encapsulated in human erythrocytes by a procedure based on hypotonic hemolysis and isotonic resealing. Encapsulated FdUMP (up to 9 mumol/ml of packed erythrocytes) did not affect erythrocyte metabolism or morphology. Hemolysates were found to catalyze efficient dephosphorylation of FdUMP to yield nearly stoichiometric amounts of the corresponding deoxyribonucleoside 5-fluoro-2'-deoxyuridine (FdUrd), an antineoplastic drug showing selective cytotoxicity toward liver metastases from colorectal carcinomas. The dephosphorylation reaction had an apparent Km of 7.7 +/- 1.2 mM FdUMP at pH 7.4 and was remarkably slower at pH 8.2. ATP, GTP, and UTP inhibited both the disappearance of FdUMP and the formation of FdUrd in hemolysates. The enzyme responsible for the FdUMP-to-FdUrd conversion was identified with the deoxyribonucleotide-specific isozyme of erythrocyte pyrimidine 5'-nucleotidase (EC 3.1.3.5). Intracellular formation and subsequent release of FdUrd were observed in intact erythrocytes loaded with FdUMP. Inhibition of FdUrd release from these erythrocytes was obtained by raising the pH intracellularly and, alternatively, by coencapsulation of ATP. Autologous FdUMP-loaded erythrocytes might be used as endogenous bioreactors designed for time-programmed and liver-targeted delivery of FdUrd.

Antineoplastic Agents↗
PubMed1988

Rioprostil: a clinical experience in gastric ulcer treatment.

The efficacy and tolerability of the prostaglandin E1 derivative rioprostil (Bay o 6893) was studied in a randomized, double-blind, placebo-controlled trial in 40 patients affected by acute gastric ulcer. At the end of the eight weeks period ulcer healing was achieved in 85% of the rioprostil-treated patients and in 60% of the placebo-treated ones (p less than 0.05). Rioprostil produced a significant reduction of pain and also improved the clinical status. This positive outcome was noted both in smokers and in non-smoking patients, while only this last group improved during the placebo treatment.

Administration, Oral↗
PubMed1988

In vivo liver and lung targeting of adriamycin encapsulated in glutaraldehyde-treated murine erythrocytes.

Treatment of adriamycin-loaded erythrocytes from B6D2F1 mice with 0.1% glutaraldehyde produced the following effects: a considerable decrease in the in vitro leakage of the unmodified drug and a selective liver (and, to a lesser extent, lung) uptake of the encapsulated drug (70% of the injected dose) compared to drug leakage from, and tissue distribution of, carrier erythrocytes not treated with glutaraldehyde. The liver vascular bed was not saturated by five daily intravenous injections of 20 microliters of glutaraldehyde-treated erythrocytes, which allows a total dosage of 200 micrograms of the drug (half the LD50 value) to be administered. No appreciable liver damage results from extensive and prolonged uptake of glutaraldehyde-treated carrier erythrocytes. Entrapment of adriamycin within erythrocytes along with glutaraldehyde treatment of the carrier cells seems to be a promising therapeutic strategy against liver (and lung) tumors.

Animals↗