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Biomedical subjects

S Romagnoli

Publications and source records attributed to S Romagnoli.

At least 37 records · Page 2Linked to original sources

Roles of chemosensory pathways in transient changes in swimming speed of Rhodobacter sphaeroides induced by changes in photosynthetic electron transport.

The response of free-swimming Rhodobacter sphaeroides to increases and decreases in the intensity of light of different wavelengths was analyzed. There was a transient (1 to 2 s) increase in swimming speed in response to an increase in light intensity, and there was a similar transient stop when the light intensity decreased. Measurement of changes in membrane potential and the use of electron transport inhibitors showed that the transient increase in swimming speed, following an increase in light intensity, and the stop following its decrease were the result of changes in photosynthetic electron transport. R. sphaeroides has two operons coding for multiple homologs of the enteric chemosensory genes. Mutants in the first chemosensory operon showed wild-type photoresponses. Mutants with the cheA gene of the second operon (cheAII) deleted, either with or without the first operon present, showed inverted photoresponses, with free-swimming cells stopping on an increase in light intensity and increasing swimming speed on a decrease. These mutants also lacked adaptation. Transposon mutants with mutations in cheAII, which also reduced expression of downstream genes, however, showed no photoresponses. These results show that (i) free-swimming cells respond to both an increase and a decrease in light intensity (tethered cells only show the stopping on a step down in light intensity), (ii) the signal comes from photosynthetic electron transfer, and (iii) the signal is primarily channelled through the second chemosensory pathway. The different responses shown by the cheAII deletion and insertion mutants suggest that CheWII is required for photoresponses, and a third sensory pathway can substitute for CheAII as long as CheWII is present. The inverted response suggests that transducers are involved in photoresponses as well as chemotactic responses.

Antimycin A↗

Constitutive expression of interleukin-1beta (IL-1beta) in rat oligodendrocytes.

The RT-PCR analysis of RNA from progenitor and differentiated primary rat oligodendrocytes, and from the oligodendrocyte CG-4 cell line, shows the presence of the IL-1beta mRNA, the type I IL-1beta receptor and the IL-1 receptor accessory protein in these cells. In situ hybridization of a rat IL-1beta probe to primary progenitor and differentiated rat oligodendrocytes results in a positive signal. The double hybridization of the IL-1beta probe, together with an oligodendrocyte-specific differentiation marker, to sections of postnatal rat brain at different stages of differentiation is also positive. The double immuno-labelling technique utilized indicates coincidence of the signals on the brain slices. The results show that IL-1beta mRNA is constitutively expressed in rat brain oligodendrocytes from 1 day after birth onward. In agreement with this observation, CG-4 cells, primary progenitor and differentiated rat oligodendrocytes are positively stained by antibodies against IL-1beta. Postnatal brain slices from 1 and 4 day old and adult rats, labelled with a double immunofluorescence technique, are also stained by antibodies against IL-1beta. This signal coincides with that of antibodies against oligodendrocyte-specific surface markers. We conclude that IL-1beta is constitutively expressed in rat brain progenitor and differentiated oligodendrocytes.

Animals↗

Acute tubulo-interstitial nephritis requiring dialysis associated with intermittent rifampicin use: case report.

Rifampicin is one of the most effective antibiotics used for the treatment of tuberculosis and severe staphylococcal infections. Intermittent administration of high doses of rifampicin has been associated with frequent adverse reactions, including hepatotoxicity and nephrotoxicity, sometimes resulting in acute renal failure. We describe a case of rifampicin-associated acute renal failure, with biopsy findings of tubulointerstitial nephritis; inflammatory cells were characterized by immunohistochemistry, which showed immunoreactivity for CD3 and CD5 (T lymphocytes) and for CD68 (macrophages). The patient presented with a very rapid systemic reaction to the offending drug and rapid deterioration of renal function, which required dialysis treatment. The response to rifampicin discontinuation was excellent: no further therapy was required, as renal function began to improve within several days and returned to normal values (serum creatinine 1.17 mg/dl) seven months after the onset of symptoms. When prescribing rifampicin the physician should investigate previous use of the drug, because re-exposure is a critical factor in predicting the possibility of drug-induced acute renal failure.

Acute Disease↗

Monomeric bovine beta-lactoglobulin adopts a beta-barrel fold at pH 2.

We have determined a crude structure of the apo form of bovine beta-lactoglobulin, a protein of 162 amino acid residues with a molecular mass of 18 kDa, at a low pH on the basis of data collected using only homonuclear 1H NMR spectroscopy. An ensemble of protein conformations was calculated with the distance-geometry algorithm for NMR applications (DYANA). The monomeric protein at low pH adopts a beta-barrel fold, well-superimposable on the structure determined by X-ray crystallography for the dimer at physiological pH. NMR evidence suggests the presence of disordered loop regions and terminal segments. Structural differences between the monomer at pH 2 and the dimer at pH 7, obtained by X-ray crystallography, are discussed, paying particular attention to surface electrostatic properties, in view of the high charge state of the protein at low pH.

Algorithms↗

Cypermethrin-induced alteration of thymocyte distribution and functions in prenatally-exposed rats.

The synthetic pyrethroid insecticide, cypermethrin (50 mg/kg) was given during gestation to pregnant rats by gavage in corn oil. Prenatal cypermethrin exposure induced a significant decrease in the absolute number of all thymocyte subsets during the first 30 days after birth, being the double negative CD4-CD8-, single positive CD4 and CD8 T cells preferentially affected. Later on day 60 and 90 double positive CD4+CD8+ and single positive thymocytes gradually recovered, while the total number of CD4 CD8 cells was increased. Moreover, thymocytes from rats prenatally exposed to cypermethrin showed an impaired ability to proliferate in response to different doses of Concanavalin A (ConA) and human recombinant interleukin-2 (hrIL-2) and to produce and/or release IL-2. Overall, our results indicate that cypermethrin administered during prenatal period can affect multiple steps in thymocyte differentiation pathways resulting in an altered cell subset distribution and an impairment of thymocyte functions.

Animals↗

Acute serum calcium changes in transient ischemic attack and cerebral infarction.

Total (T-Ca), albumin corrected (A-Ca) and ionized (Ca++) serum calcium levels were measured in patients affected by transient ischemic attack (TIA) and ischemic cerebral infarction (ICI), in order to evaluate the clinical and prognostic significance of calcemic status during the acute phase of these events. These results demonstrate that the calcium level is decreased in cerebral ischemia and that more substantial changes are observed in ICI than in TIA and controls (p < 0.0001, p < 0.02 and p < 0.0001 respectively for T-Ca, A-Ca and Ca++; analysis of variance). The mean T-Ca was significantly reduced in patients who died during hospitalization compared with values observed in survivors (p < 0.005), whereas A-Ca and Ca++ were not different. The calcium changes observed in the early phase of TIA and ICI suggest that the severity of cerebral ischemia may condition the amount of its acute decrease. The cause of hypocalcemia is unclear (primary effect or secondary epiphenomenon of cerebral ischemia?), but when A-Ca and Ca++ are considered, its in-hospital unfavorable prognostic role may be excluded.

Aged↗

Clinical and prognostic significance of hyperfibrinogenemia in cerebral ischemia.

In order to evaluate the clinical and prognostic significance of early hyperfibrinogenemia in patients with transient ischemic attack (TIA) and ischemic cerebral infarction (ICI), we analyzed the relationships between plasma fibrinogen, brain damage severity, clinical status on admission and intra-hospital mortality. Vascular damage severity was estimated by measuring the necrotic area by computed axial tomography (CT) and indirectly by means of changes in some plasma enzymes (CK, LDH, GPT/ALT, and GOT/AST). Plasma fibrinogen levels were statistically higher in ICI than in TIA and control subjects (p < 0.0005; analysis of variance). Moreover, plasma fibrinogen was directly related to the extension of the necrotic area at CT scan (p < 0.05) and in ICI patients was positively correlated with CK (r = 0.50, p < 0.01), LDH (r = 0.41, p < 0.05) and GOT/AST (r = 0.42, p < 0.05) serum levels, but not with GPT/ALT. A higher plasma fibrinogen value was observed in patients with stupor or coma compared with those with alert consciousness (p < 0.05). In patients who died during hospitalization, fibrinogen levels were higher than those of subjects who were discharged (p < 0.005). The results indicate that in the early phase of cerebral ischemia, plasma fibrinogen levels are related to the severity of the clinical status and to the extension of the brain vascular damage, thus representing a negative clinical and prognostic factor of the disease.

Aged↗

Prenatal exposure to cypermethrin modulates rat NK cell cytotoxic functions.

The synthetic pyrethroid insecticide, cypermethrin, was given during gestation to pregnant rats by gavage in corn oil. Peripheral blood and spleen cytotoxic activity of dams and their offspring were then evaluated at different times (30, 60, 90, 120 days) after birth. Pups showed a significant increase in peripheral blood natural killer (NK) and antibody-dependent (ADCC) cytotoxic activity paralleled with a similar increase in the percentage of NK-RP1+ cells and decreased activity in the spleen. Pregnant cypermethrin-exposed dams showed no changes in peripheral blood or spleen cytotoxic function during the postnatal period. Overall, these results suggest that immunomodulation of cytotoxic activity observed in the offspring is likely attributable to a specific effect of cypermethrin administered during the prenatal period.

Animals↗

Serum albumin level at admission: mortality and clinical outcome in geriatric patients.

We evaluated serum albumin at time of admission, within 72 hours, in 135 geriatric patients who were older than 70 years to establish its role as a predictor of death and clinical outcome at time of discharge. Serum albumin values were reduced significantly in patients who died compared with those who were discharged in unchanged/impaired and improved conditions (3.01 +/- 0.68 g/dL, 3.18 +/- 0.55 g/dL, and 3.65 +/- 0.52 g/dL respectively, P < 0.0001). A correlation between serum albumin concentration at admission and number of days elapsed from admission and death was found (r = 0.43, P < 0.05). Mortality rate was 38.6% in patients with serum albumin values < 3.3 g/dL compared with 14.1% in those with albumin values > or = 3.3 g/dL (P < 0.005). Similar results were obtained even when the main diagnostic conditions, such as cardiocerebrovascular disease and cancer, were considered. The results demonstrate that in geriatric patients the serum albumin level at admission may be a predictor of mortality and clinical outcome at discharge.

Aged↗

The use of early pregnant mares as embryo recipients.

Fourteen normal, cyclic mares, treated to synchronise oestrus and ovulation and inseminated artificially with fresh semen, were assigned to a donor or a recipient group after ovulation, with the aim of obtaining a degree of synchrony of > or =2 days. Ten embryos, collected on Day 6 or 7 after ovulation (Day 0), were transferred nonsurgically to inseminated recipient mares (IRM) that had ovulated up to 5 days after the respective donors, or to pregnant recipient mares (PRM) that had ovulated 2-7 days before the donors. Embryonic size and development, as determined by ultrasound examination, were used to distinguish embryos derived from the recipient (recipient embryo = RE) or from the donor (transferred embryo = TE) mare. In cases of twin pregnancy, the RE was manually squeezed on Days 14-16. Abortion was induced in all mares on Day 30. Three of 6 TE developed in IRM. Two of 6 IRM developed a twin pregnancy (RE+TE), while 4 of 6 IRM developed a singleton pregnancy (1 TE and 3 RE). None of 4 TE developed in Day 9-14 PRM and one of these PRM lost her own embryo following ET. The experiment demonstrated that a mare can carry her own embryo and a transferred embryo simultaneously. However, the status of pregnancy does not improve conception rate in recipient mares that ovulate prior to the donor.

Animals↗

[Use of ropivacaine in axillary brachial plexus block].

The aim of the study was to evaluate the efficiency and safety of ropivacaine, in comparison with bupivacaine, in axillary brachial plexus block. 24 patients, undergoing upper limb surgery, was divided into 2 homogeneous groups and the local anaesthetics was administered: A (ropivacaine 0.75%, 25 ml; total dose 187.5 mg) and B (bupivacaine 0.5%, 25 ml; total dose 125 mg). The axillary plexus block was executed with the help of an electrostimulator. The results show that using ropivacaine the onset-time is lower and the duration of sensory and motor block is higher than using bupivacaine. In conclusion we can affirm that ropivacaine is a new step in local anaesthetic field.

Adult↗

[Peridural analgesic therapy in orthopedic surgery: comparison of ropivacaine and bupivacaine].

The aim of our study was to compare the efficiency of ropivacaine and bupivacaine, in epidural administration, in postoperative analgesia. 20 patients, undergone knee surgery, in epidural anaesthesia (bupivacaine 0.5%-2 mg/Kg-1 administered in level L3L4), was divided into 2 groups (10 each one) and the local anaesthetics in study was administered by epidural catheter with an elastomeric pump: A (ropivacaine 0.15%) and B (bupivacaine 0.15%). The results demonstrate that ropivacaine is better than bupivacaine to keep a check on analgesia in postoperative pain.

Adult↗

[Use of mivacurium in orthopedic surgery: comparison of 2 different-dose inductions].

The aim of our study was to evaluate the efficiency and safety of mivacurium, comparing two dose-induction in patients undergone a minor orthopaedic surgery. 30 patients were divided into two groups and mivacurium were administered at the dose of 0.15 mg Kg-1 and 0.20 mg Kg-1 respectively. The results confirmed its efficiency in short surgery. Mioresolution was excellent only in the second group (0.20 mg Kg-1) despite an histamine-related blood pressure reduction.

Adjuvants, Anesthesia↗

p53 overexpression and human papillomavirus infection in transitional cell carcinoma of the urinary bladder: correlation with histological parameters.

Seventy-nine transitional cell carcinomas (TCCs) of the urinary bladder (25 grade 1, 22 grade 2, and 32 grade 3 tumours) were examined for p53 overexpression by immunohistochemistry with a monoclonal antibody and for human papillomavirus (HPV) infection by the polymerase chain reaction (PCR). Positive immunostaining for p53 was detected in 40.5 per cent of the cases; the percentage of positive cases was significantly lower in low-grade (G1 and G2) TCCs than in high-grade (G3) tumours (10.6 per cent vs. 84.4 per cent; P < 0.0001). The overall rate of HPV infection was 32.9 per cent; 20.3 per cent of the cases were positive for HPV 16, 3.8 per cent for HPV 18, and 8.9 per cent for both. Consensus primers as well as type-specific primers for HPV types 6, 11, and 33 failed to detect any additional case with HPV infection. The prevalence of HPV 16 and/or HPV 18 infection was significantly higher in low-grade than in high-grade tumours (44.7 per cent vs. 15.6 per cent; P = 0.0061). p53-positive cases were more common among papillary, deeply infiltrating tumours, and HPV-positive cases among papillary, non-infiltrating lesions. According to these data, p53 overexpression and HPV 16/18 infection are common findings in bladder TCC and there appears to be an inverse correlation of p53 overexpression and of HPV infection with tumour aggressiveness. The possibility of different molecular pathways in superficial low-grade and in invasive high-grade tumours is suggested.

Adult↗

Possible mechanism of action for the attenuation of ethanol intake induced by ritanserin in rats.

The 5-HT2 receptor antagonist, ritanserin, reduces alcohol intake in rats and the nucleus accumbens (NAC) has been proposed as a site of action for the drug. Recent microdialysis studies have shown that acute subcutaneous (SC) administration of ritanserin increases extracellular 5-HT levels in the NAC. The present study evaluated, in genetically heterogeneous rats with developed preference for 3% ethanol, whether the attenuation of ethanol intake induced by ritanserin might be related to its effect on the synaptic availability of 5-HT in the NAC. Damaging 5-HTergic neurons by intracerebroventricular infusion of 5,7-dihydroxytryptamine (5,7-DHT) abolished the effect of ritanserin on ethanol consumption. Injections of the 5-HT3 receptor antagonist MDL 72222 into the NAC significantly reduced the inhibitory effect of SC injection of ritanserin, 1 mg/kg, and completely abolished the effect of ritanserin, 0.1 mg/kg. Subcutaneous injections of MDL 72222, 0.3 mg/kg 3 times/day, suppressed the effect of SC ritanserin, 0.1 mg/kg. The present findings, together with those of previous experiments showing that the tryptophan hydroxylase inhibitor p-chlorophenylalanine abolishes the effect of ritanserin, support the hypothesis that its effect on ethanol intake may be due to increased synaptic availability of 5-HT into the NAC.

5,7-Dihydroxytryptamine↗

The effects of decyl aurachins C and D on the respiratory electron flow of facultative phototrophic bacteria.

Decyl aurachins C and D are two synthetic compounds related to the natural products aurachins C and D extracted from Stigmatella aurantiaca. Titrations of a range of partial respiratory activities in membranes from facultative phototrophs indicate that decyl aurachin C is more effective than aurachin D in inhibiting the quinol oxidase. Decyl aurachin C also affects the NADH-ubiquinone oxidoreductase of Rhodobacter capsulatus and the cytochrome bc1 complexes of Rb.capsulatus and Rhodospirillum centenum. Titration of the light-induced respiration in Rsp.centenum allowed us to estimate an upper limit for the ubiquinol oxidase concentration of 1.5 +/- 0.2 nmol/mg protein, or a ubiquinol oxidase/cytochrome c oxidase ratio of 3:1.

Bacteria↗

Human papillomavirus types 16 and 18 infection in infiltrating adenocarcinoma of the cervix: PCR analysis of 138 cases and correlation with histologic type and grade.

The authors investigated by PCR 138 infiltrating cervical adenocarcinoma (27 grade 1, 76 grade 2, and 35 grade 3) for the presence of human papillomavirus (HPV) 16 and 18 infection. They included 95 (68.8%) mucinous and 43(31.2%) non-mucinous tumors. The overall prevalence of HPV infection was 84.8%; 28.3% of the cases were positive for HPV 16, 29.7% for HPV 18, and 26.8% for both HPVs. Amplification of HPV 16 and 18 negative cases with consensus primers MY09/MY11 failed to yield any additional tumors with HPV DNA sequences. Patients with HPV infection were younger than the patients who were HPV-negative (P = .001). The type of HPV was unrelated to age. Human papillomavirus infection was found in 95.8% mucinous and in 60.5% non-mucinous tumors (P < .001), with even distribution among grade 1, 2 and 3 adenocarcinoma. Our findings confirm the key role of HPV 16 and 18 in the development of cervical adenocarcinoma, particularly in mucinous histotypes. The absence of HPV infection, the old age of patients and the non-mucinous differentiation may identify a subset of cervical adenocarcinoma with different etiopathogenesis.

Adenocarcinoma↗