[The use of tissue expanders in mandibular reconstruction].
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Equipment Design↗
Biomedical subjects
P Ferrari
Publications and source records attributed to P Ferrari.
Lipoproteins during antihypertensive therapy. Study supported by the Swiss National Science Foundation.
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Adrenergic beta-Antagonists↗
[Clinical aspects, differential diagnosis and evolution of visual epileptic seizures in children].
We studied 13 boys and girls, treated for ictal visual episodes, followed-up in the Center for Epilepsy of the University of Modena. In 10 cases visual symptoms (amaurosis, hallucinations, and illusions) started between 6 and 14 years, associated with occipital EEG anomalies. In 6 cases, EEG abnormalities (sharp-waves, slow waves, spikes, spike-waves) disappeared after eyes opening. In the history of half of our cases, there was no significant antecedent. Normal intelligence and behaviour were present in all cases. Only in one case, CT demonstrated bilateral occipital calcifications. In the other 9, visual ictal symptoms disappeared after antiepileptic treatment. We think that these last cases present the characteristic features of Benign Occipital Epilepsy described by Gastaut (1982-1985). On the basis of our results, we can confirm the existence of this syndrome, even if it is rare. Nevertheless, 3 of our cases with visual symptoms, don't show the typical picture of BOE, and must be diagnostically distinguished from psychiatric disorders, basilar migraine, and other partial epilepsies.
Adolescent↗
Deaminoteicoplanin and its derivatives. Synthesis, antibacterial activity, and binding strength to Ac-D-Ala-D-Ala.
Teicoplanin and its acid hydrolysis products were deaminated with hydroxylamine-O-sulfonic acid (HOS). A few amides of these deaminoteicoplanins were also prepared. The loss of the terminal amino group reduces in vitro activity against staphylococcal and streptococcal bacteria to one-half to one-third, while binding strength to Ac-D-Ala-D-Ala, measured by differential UV spectroscopy, is reduced to one-tenth that of teicoplanin. The in vitro activity is further reduced by the presence of serum, and this is attributable to the increased lipophilicity and total negative charge of the deamino compounds. Comparison of UV spectra of deaminoteicoplanins with those of parent compounds made it possible to single out the most acid phenol group of teicoplanin aglycon (OH-4; pK = 8.2).
Anti-Bacterial Agents↗
Synthesis and biological evaluation of de(acetylglucosaminyl)didehydrodeoxy derivatives of teicoplanin antibodies.
A series of 34-de(acetylglucosaminyl)-34-deoxy derivatives of 34,35- and 35,52-didehydro teicoplanin antibiotics have been synthesized from teicoplanin and its N-acetylglucosamine containing pseudoaglycons under basic conditions. The structures of these compounds have been determined by 1H NMR, UV, and FAB-MS. 35,52-Unsaturated derivatives maintained in vitro and in vivo antimicrobial activity to a different extent as well as the ability for binding to Ac2-L-Lys-D-Ala-D-Ala, a bacterial cell-wall model for the site of action of glycopeptide antibiotics. In contrast, 34,35-unsaturated compounds were markedly less active and possessed a negligible affinity for the synthetic tripeptide.
Acetylglucosamine↗
Synthesis and biological properties of N63-carboxamides of teicoplanin antibiotics. Structure-activity relationships.
The condensation of the carboxyl function of teicoplanin A2 (CTA) and its acidic hydrolysis pseudoaglycons (TB, TC) and aglycon (TD) with amines carrying various functional groups and chains produced amide derivatives with different isoelectric points and lipophilicities. Amide formation did not affect the ability of these compounds to bind to Ac2-L-Lys-D-Ala-D-Ala, a model for the natural peptide binding site in bacterial cell walls. The antimicrobial activities of teicoplanin amides were found to depend mostly on their ionic and lipophilic character and on the type and number of sugars present. Positively charged amides were generally more in vitro active than the respective unmodified antibiotics against Gram-positive organisms. In particular, most basic amides of CTA were markedly more active than teicoplanin against coagulase-negative staphylococci. A few amides of TC and most of those of TD also showed a certain activity against Gram-negative bacteria. In experimental Streptococcus pyogenes septicemia in the mouse, some basic amides were more active than the parent teicoplanins when administered subcutaneously. Some of those of CTA were also slightly more effective than teicoplanin by oral route.
Amides↗
A possible primary role for the kidney in essential hypertension.
The role of the kidney in "essential" or "genetic" types of hypertension has been evaluated both in a rat model such as the Milan hypertensive strain (MHS) or in humans. In both species, abnormalities of renal function have been demonstrated before the development of hypertension. Moreover hypertension could be "transplanted" with the kidney when kidney cross-transplantation was carried out between MHS and the Milan normotensive strain (MNS). Also in humans, the familiality for hypertension of the donor affected the requirement of antihypertensive therapy of the recipient. Further studies furnished results that were consistent with the hypothesis that a primary increase in Na transport across the tubular cell could be responsible for the pressor effect of the kidney in MHS or in humans. Because many similarities were found between the function of the tubular cell and the red blood cell in MHS, red blood cells were used to gain information about the molecular genetic mechanisms underlying these cellular changes. The results so far obtained showed that red blood cell abnormalities in MHS were genetically determined within the stem cells and genetically associated with the development of hypertension in F2 hybrids obtained by crossing the F1 (MHS X MNS). Moreover, the abnormal Na transport across the cell membrane may be due to an abnormal function of the membrane skeleton proteins. Studies are in progress to evaluate a possible cause-effect relationship between: membrane skeleton protein-ion transport across the cell membrane and the development of hypertension.
Animals↗
Erythrocyte adducin differential properties in the normotensive and hypertensive rats of the Milan strain. Characterization of spleen adducin m-RNA.
Previous studies have shown that erythrocytes from the Milan hypertensive strain of rats (MHS) differ from erythrocytes from the control normotensive strain (MNS). These differences are determined within the stem cells, are genetically associated with the development of hypertension, and are similar to those found between the tubular cells of the two strains. Moreover they seem to be dependent upon the presence of the membrane skeleton proteins. In this paper we describe our studies aimed at identifying some precise protein difference between the membrane skeletons of the two strains, which may cause the cellular differences described above. Milan hypertensive strain and MNS rats were immunized with ghost or membrane skeleton extracts prepared from the other or their own strains. Only MHS rats immunized with MNS ghost or membrane skeleton extracts produced an antibody against a 105 KD protein in about 95% of the animals. This protein has been identified with the recently described cytoskeletal protein adducin on the following bases: the protein binds calmodulin (CaM) and protein kinase C (PKc) in a Ca2+ dependent way. It also binds phosphatidylserine, is the substrate of exogenous PKc, and finally it is purified by high salt extraction of Triton-X100 insoluble erythrocyte cytoskeletons followed by affinity chromatography on CaM-sepharose. Using this antibody the isolation from a mouse spleen library, the characterization and sequencing of a partial cDNA clone coding for this protein has been carried out. In conclusion adducin may be considered a very useful tool to test the hypothesis that the cellular differences between MHS and MNS may be caused by a difference in a membrane skeleton protein.
Amino Acid Sequence↗
Evidence for a specific role of GnRH pulse frequency in the control of the human menstrual cycle.
An adequate frequency of gonadotropin-releasing hormone (GnRH) pulses appears to be important for physiological gonadotropin secretion. However, limited information exists on the exact role of this parameter in the regulation of the human menstrual cycle. Thus we studied gonadotropin and gonadal steroid secretion in 32 women with primary hypogonadotropic amenorrhea who received pulsatile GnRH (60 to 120 micrograms/day) at 60- or 120-min intervals for a total of 64 ovulation induction cycles. Ovulation was achieved in 94% of 60-min and in 70% of 120-min cycles P less than 0.05). In the follicular phase of ovulatory cycles, estradiol (E2) levels did not differ among the four groups; however, mean luteinizing hormone (LH) levels were lower (P less than 0.005), and the midcycle LH surge was severely blunted in cycles of subjects receiving 120 micrograms/day (5 micrograms/bolus) GnRH every 120 min compared with subjects receiving the same dose of GnRH per day or per bolus every 60 min. Luteal progesterone (only in 60 micrograms/day GnRH cycles) and E2 levels were lower in 120-min than in 60-min cycles (P less than 0.05). The use of the higher daily GnRH dose (120 micrograms/day) reduced or abolished the frequency-associated hormone level differences. We conclude that a low frequency of pulsatile GnRH in women 1) decreases mean LH levels and blunts the midcycle gonadotropin surge, 2) does not increase follicle-stimulating hormone concentrations, and 3) is associated with a reduced rate of ovulation.
Adult↗
The abnormal response of polycystic ovarian disease patients to exogenous pulsatile gonadotropin-releasing hormone: characterization and management.
Pulsatile GnRH administration for induction of ovulation is often ineffective in polycystic ovarian disease (PCOD) patients. To clarify and correct the endocrine mechanisms underlying this deranged response we gave pulsatile GnRH (5 micrograms, iv, every 60 min) to idiopathic hypogonadotropic hypogonadism (IHH) patients with primary amenorrhea for 19 cycles and to PCOD patients for 24 cycles before (pre-A) and for 25 cycles after (post-A) GnRH analog suppression. Compared to IHH, pre-A cycles were characterized by elevated LH, estradiol, and testosterone; reduced luteal phase progesterone; and low ovulatory (38%) and pregnancy rates (8%). Conversely, LH, estradiol, and follicular phase testosterone levels were lower in post-A than in pre-A cycles, while luteal phase progesterone was higher; the endocrine pattern of post-A cycles closely resembled the one of IHH cycles. The ovulatory and pregnancy rates of PCOD patients improved remarkably in post-A cycles (90% and 38%, respectively). Excessive body weight was associated with a lower incidence of ovulation in both pre-A (15%) and post-A cycles (75%). A worse endocrine pattern and a lower ovulatory rate (50%) were obtained when a second consecutive post-A cycle occurred without repeating GnRH analog suppression. No signs of even mild ovarian hyperstimulation and no multiple pregnancies were recorded in the post-A cycles. We conclude that in PCOD 1) deranged pituitary sensitivity, excessive ovarian androgen secretion, and obesity critically affect folliculogenesis and ovulation; 2) pituitary-gonadal suppression with a GnRH analog markedly improves the endocrine and clinical responses to pulsatile GnRH ovulation induction; 3) optimal results can be achieved only when each pulsatile GnRH cycle is preceded by GnRH analog suppression; and 4) pulsatile GnRH is highly effective and safe for ovulation induction, provided that PCOD subjects are pretreated with a GnRH analog.
Adult↗
Thioureas and isothiouronium salts of the aglycone of teicoplanin. I. Synthesis and biological activity.
A series of thiourea and isothiouronium salt derivatives of the aglycone of teicoplanin was prepared by reaction of the terminal amino group with isothiocyanates, followed by S-alkylation of the thiourea compounds. Unexpectedly, the two classes of derivatives show a similar in vitro antibacterial activity against Gram-positive bacteria. Thiourea compounds, due to the lack of a positively charged N-terminus group, have a 10-fold lower binding constant to Ac-D-Ala-D-Ala, a bacterial cell-wall model, than the parent antibiotic and isothiouronium salt derivatives.
Anti-Bacterial Agents↗
An unexpected intramolecular cyclization of isothiouronium teicoplanins. II. Reaction mechanism and biological activity.
N15-Isothiouronium derivatives of teicoplanin and its aglycone submitted to alkaline condition give rise to an intramolecular cyclization. The structures of the new gamma-lactam derivatives were determined by using 1H NMR, IR and fast atom bombardment mass spectra. The cyclization mechanism was interpreted on the basis of the identification of the intermediate structure. The poor in vitro antibacterial activity of the new cyclic compounds and the negligible affinity for the synthetic peptidoglycan model Ac2-L-Lys-D-Ala-D-Ala is probably due to the lack of the N-17 amidic proton and to the lack of the basic character of the nitrogen in position 15.
Anti-Bacterial Agents↗
Dechloro teicoplanin antibiotics.
Mono- and didechlorinated derivatives of the antibiotic teicoplanin, its pseudoaglycones and aglycone, and of one amide and ester of deglucoteicoplanin were prepared under selective reductive conditions. The selectivity and rate of dehalogenation were studied and compared to those of vancomycin and deglucovancomycin. The influence of the chlorine substituents on the mechanism of action and antibacterial activity of teicoplanin antibiotics was also investigated.
Animals↗
Synthesis and biological activity of N63-carboxypeptides of teicoplanin and teicoplanin aglycone.
A series of peptide derivatives of teicoplanin A2 (CTA) and deglucoteicoplanin (TD) was prepared by condensation of the 63-carboxyl function with the alpha-amino group of selected amino acids and their derivatives. The modification of the ionic character of CTA and TD influenced their in vitro and in vivo antimicrobial properties to a different extent, depending on the structure of the amino acidic moiety at C-63. A certain effect on binding strength to Ac2-L-Lys-D-Ala-D-Ala, a synthetic model of the antibiotic's target peptide, was also observed.
Animals↗
Isolation and structure determination of two new analogs of teicoplanin, a glycopeptide antibiotic.
Teicoplanin is an antibiotic produced by fermentation of Actinoplanes teichomyceticus as a complex formed by five closely related glycopeptides characterized by different fatty acid chains of ten and eleven carbon atoms. In addition, minor quantities of related substances are present. Two of them, named RS-1 and RS-2, were shown to be teicoplanins having as fatty acid chains 10-methylundecanoic acid and n-dodecanoic acid, respectively. Other two related substances, named RS-3 and RS-4, have now been isolated and purified starting from fermentation broths of a mutant of the same microorganism producing them in substantial amounts. This was achieved by semipreparative reversed-phase liquid chromatography carried out on high-pressure scale. The structures were assigned on the basis of 1H NMR spectra and homonuclear COSY 2D experiments and fast atom bombardment MS spectrometry, in comparison with the large mass of data till now accumulated on teicoplanin. RS-3 and RS-4 are teicoplanins having as fatty acid chains 6-methyloctanoic acid and n-nonanoic acid, respectively.
Actinomycetales↗
A42867, a novel glycopeptide antibiotic.
A42867 is a new glycopeptide antibiotic of the ristocetin-vancomycin class active against aerobic and anaerobic Gram-positive bacteria. A42867 is produced by a strain of Nocardia nov. sp. ATCC 53492. A42867 was isolated during a screening program aimed at the discovery of new members of this glycopeptide class of antibiotics, by affinity chromatography based on an acyl-D-alanyl-D-alanine probe. The structure of A42867 was elucidated by fast atom bombardment MS, high field 2D 1H NMR spectroscopy, and HPLC analysis of the hydrolyzed carbohydrates. A42867 differs from vancomycin in the sugar portion and in the presence of only one chlorine atom in the peptide core. Its biological activity on Gram-positive aerobic and anaerobic bacteria is similar to that of other antibiotics of this group.
Aminoglycosides↗
[Type A behavior and cardiovascular reactivity. Preliminary findings].
In view of reports of a connection between ischaemic cardiopathies and "A" type behaviour, the response of certain cardiocirculatory parameters to given physical stimuli was investigated in a group of people doing high stress work. The data did in fact reveal a tendency to more pronounced cardiovascular reactivity in the A group, a difference that was statistically significant in the cold pressor and cold tests. The possible links between enhanced vasomotor response and increased risk of coronary heart disease are pointed out with emphasis on recent hypotheses about the possible pathogenic role of enhanced 5-OH-tryptamine release and particular alterations in the alpha/beta adrenergic receptor balance.
Adult↗
Characterization of erythrocyte adducin from the Milan hypertensive strain of rats.
Previous studies showed that erythrocytes from the Milan hypertensive strain of rats (MHS) are smaller and have a faster Na-K cotransport when compared with their normotensive controls (MNS). These characteristics are determined within the stem cell, are genetically associated with hypertension and are similar to other renal tubular cell abnormalities more directly involved in the development of hypertension in MHS. The difference in volume is maintained in ghost membranes, while the difference in transport is abolished in inside-out vesicles. Ghosts and cytoskeletons contain a 105-kilodalton protein already characterized by immunoblotting. This protein has been identified with erythrocyte adducin by several criteria, including binding to calmodulin and protein kinase C, phosphorylation and full immunological cross-reactivity with human adducin. Since only MHS rats immunized with MNS erythrocyte cytoskeletons produce anti-adducin antibodies, we suggest an immunogenic structural difference in adducin from the two strains, and an involvement of this difference in the alteration of Na-K cotransport observed.
Animals↗