PubMed Health⌕ Search

Biomedical subjects

M Geraci

Publications and source records attributed to M Geraci.

25 records · Page 2Linked to original sources
PubMed1985

Protonic conductivity of hydrated lysozyme powders at megahertz frequencies.

Dielectric losses were measured for lysozyme powders of varied hydration level by a dielectric-gravimetric technique in the frequency range of 10 kHz to 10 MHz. The relaxation showed an isotope effect and pH dependence, indicating that the inferred conductivity is protonic. The transport process is likely restricted to the surface of individual macromolecules and involves shifting of protons between ionizable side chain groups of the protein. The time constant of the relaxation shows cooperativity in its seventh-order dependence on bound protons. The process develops in the hydration region critical for the onset of the catalytic properties of the enzyme. The binding of a substrate increases the relaxation time by a factor of 2. These observations suggest that the megahertz dispersion reflects behavior at the protein surface, specifically the cooperative channeling of proton flow through the active site, that may be of particular significance for the enzymatic and other functional properties of proteins.

Electric Conductivity↗
PubMed1979

Repair kinetics of DNA, RNA and proteins in the tissues of mice treated with doxorubicin.

Experiments in mice treated with a single 10 mg/kg dose of doxorubicin (adriamycin) i.p. revealed considerable reduction in the incorporation of 3H-thymidine in DNA and of 3H-uridine in RNA, in the spleen and liver, and at mitochondrial and non-mitochondrial level in the heart. Although protein syntheses in the heart and spleen were not reduced by the drug to any great degree, they took 10 days to return to normal; conversely, liver protein syntheses were not inhibited at all and indeed presented signs of stimulation.

Animals↗
PubMedDate not supplied

Peptides and anxiety: a dose-response evaluation of pentagastrin in healthy volunteers.

A large body of data suggest that brain cholecystokinin (CCK) systems are involved in the regulation of anxiety, and numerous studies have demonstrated that CCK-4, a CCKB agonist, reliably induces panic attacks in patients with panic disorder. Recently, pentagastrin, a commercially available CCKB agonist, has been reported to have similar anxiogenic properties. To further explore the utility of pentagastrin as a challenge agent and to determine whether its effects are dose-related, a dose-response study was conducted in ten healthy volunteers. Pentagastrin (0.2 microgram/kg, 0.6 microgram/kg and 1.0 microgram/kg) and inactive placebo were infused over one minute on four separate challenge days in a double-blind fashion. Subjects received pentagastrin while participating in a structured social interaction task. Repeated measures of anxiety, blood pressure, pulse, ACTH, and cortisol were taken at baseline and postinfusion. Pentagastrin administration led to increases in anxiety, pulse, ACTH, cortisol and physical symptoms of panic, in a dose-related manner. Participation in the social interaction task led to increases in measures of anxiety as well as increases in pulse and blood pressure. Few differences were found between the 0.2 microgram/kg dose of pentagastrin and placebo, or between the 0.6 microgram/kg and the 1.0 microgram/kg doses of pentagastrin. These findings support the notion that CCK systems are involved in the regulation of anxiety, and suggest that the 0.6 microgram/kg dose may be optimal for increasing symptoms of anxiety while minimizing unpleasant side effects. The powerful anxiogenic effects of the social interaction task underscore the importance of contextual variables in challenge studies.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Life events obtained via interview: the effect of time of recall on data obtained in controls and patients with panic disorder.

Because previous studies have documented the distorting effect of time of recall on the reporting of life events over a one-year period of time, the relation between various life event measures and time of recall over time periods greater than one year was examined in 44 patients with panic disorder and 44 control subjects. For both groups, time of recall was unrelated to any of nine life event measures. The implications of these findings for life event studies requiring retrospection greater than one year are discussed.

Adult↗
PubMedDate not supplied

[Giant mucocele of appendix. Case report].

Appendiceal mucocele is an uncommon disorder caused by accumulation of mucus within the appendiceal lumen. Mucoceles represent a heterogeneous group comprising various histopathologic lesions including mucosal hyperplasia, cystoadenomas, and cystoadenocarcinomas and prognosis is related to these subtypes. The most common symptom is pain or a palpable mass in the right lower quadrant on physical examination. The preoperative diagnosis is performed with abdominal U.S. and confirmed with CT scan; typical CT scan image is a capsulated cystic mass with calcification of the wall while U.S. pattern shows cystic lesion with the onion skin sign considered a specific sonographic marker for appendiceal mucocele. In conclusion a cystic mass sonographically detected with onion skin sign, in the presence of normal female reproductive organs, suggest the diagnosis of appendiceal mucocele.

Adult↗
PubMedDate not supplied

[Serum Ca-125 levels in aneuploidy screening in first pregnancy trimester. Authors' experience].

BACKGROUND: The aims of the current study were to investigate the value of Ca-125 maternal serum levels at the first trimester of pregnancy in order to test heir usefulness for the screening of foetal aneuploidies. MATERIALS AND METHODS: The study was performed retrospectively on frozen maternal serum samples obtained in the antenatal clinics of the department of obstetrics and gynaecology: 85 control normally cycling women, 479 pregnant over 36 years from 8th to 12th week of pregnancy underwent the villocentesis, 383 pregnant women aged from 19 to 45 years underwent the "tritest" (AFP = alpha-fetoprotein, hCG = human chorionic gonadotropin, fE3 = free estriol, age) for the screening of the Down syndrome in the second trimester of pregnancy. All newborns have been tested by Apgar score. The immunoradiometric (IRMA) Ca-125 assay was performed without knowing the result of the cytogenetic test. Over all we have had 11 patients with aneuploidy, 7 Down, 3 Edwards and 1 Patau. The levels of Ca-125 are expressed as MoM multiple of median) in order to compare the levels at different gestational age. RESULTS: We had no significant differences between normal and pathological pregnancies, therefore we don't reckon the Ca-125 assay useful in the screening of aneuploidies in the first trimester of pregnancy.

Adult↗