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Biomedical subjects

A Serra

Publications and source records attributed to A Serra.

At least 73 records · Page 4Linked to original sources
PubMed2000

Endoscopic revision of failed external dacryocystorhinostomy.

Obstruction of the lacrimal pathways is a relatively frequent problem usually corrected by external dacryocystorhinostomy. Failure of the external approach may be due to an inadequate rhinostomy, excessive scar tissue production, anatomical anomalies or concomitant paranasal sinus infectious. The introduction of direct and angled endoscopes for paranasal sinus surgery and the refinement of endoscopic surgical procedures allows a complete intranasal exposure and surgical management of the lacrimal sac, even in cases of recurrent obstruction. The present work offers a retrospective review of the records of seven patients who underwent a revision endoscopic dacriocystorhinostomy (ENDCR) between January 1994 and June 1997 for failed external dacryocystorhinostomy. The preoperative evaluation of the patients, the surgical technique and the postoperative management are examined in detail. A permanent dacryocystorhinostomy was obtained in six patients. One patient underwent a successful bilateral procedure. One patient experienced a persistent stenosis. There were no complications related to the surgical procedure. In our experience the revision endoscopic dacryocystorhinostomy offered several advantages, including a complete exposure of those anatomical anomalies or inflammatory changes of the normal structures that commonly hinder conventional external surgery. Although a larger series will further elucidate the efficacy of this procedure in failed external dacryocystorhinostomy, we recommend considering revision ENDCR as an alternative to the external revision technique.

Adult↗
PubMed2000

Effect of bioactive aldehydes on cell proliferation and c-myc expression in HL-60 human leukemic cells.

Lipid peroxidation produces several toxic carbonyls, including biologically active aldehydes. In previous studies, we demonstrated that 4-hydroxynonenal (HNE), one of the major products of lipoperoxidation, inhibited growth and c-myc expression in K562 and HL-60 human leukemic cells. In this study, we compared the HNE effects with those of 4-hydroxyoctenal (HOE), 4-hydroxyundecenal (HUE; different lengths of the lipophilic tail), and the analogous aldehydes 2-trans-nonanal (lacking the OH group) and nonenal (lacking the OH group and the trans CC double bond), on HL-60 cell proliferation and c-myc expression. HUE and HOE inhibited growth and c-myc expression in a dose-dependent fashion, with an effectiveness comparable with that of HNE, whereas 2-nonenal and nonanal did not affect these parameters. Our results showed that different aldehydes produced from lipid peroxidation may contribute to growth inhibition by c-myc downregulation and that the molecular features involved seem to be the hydroxy group and the trans CC double bond.

Aldehydes↗
PubMed1999

Normal and altered cytoarchitecture of the inner ear.

Scanning electron microscope gave new insights into real morphology of the inner ear and has enhanced basic research. In fact, during the last twenty years, the cellular system that composes the organ of Corti and the vestibular apparatus has been clearly described by many authors. We now have a better understanding of each cell type and that they have a physiological functioning as ear and vestibular system. In addition, new insights into the damage caused by many drugs, such as aminoglucosides, can be investigated by studying the morphological changes and the reparative process following the injury. Animals such as guinea pigs can be used as ideal models to investigate the alterations in the sensory epithelium of the cochlear and vestibular receptors following ototoxic poisoning.

Aminoglycosides↗
PubMed1999

Randomized comparison of coronary stent implantation and balloon angioplasty in the treatment of de novo coronary artery lesions (START): a four-year follow-up.

OBJECTIVE: The purpose of this study was to test the hypothesis that stent implantation in de novo coronary artery lesions would result in lower restenosis rates and better long-term clinical outcomes than balloon angioplasty. BACKGROUND: Placement of an intracoronary stent, as compared with balloon angioplasty, has proven to reduce the rate of restenosis. However, the long-term clinical benefit of stenting over angioplasty has not been assessed in large randomized trials. METHODS: We randomly assigned 452 patients with either stable (129 patients) or unstable (323 patients) angina pectoris to elective stent implantation (229 patients) or standard balloon angioplasty (223 patients). Coronary angiography was performed at baseline, immediately after the procedure and six months later. End points were the rate of restenosis at six months and a composite of death, myocardial infarction (MI) and target vessel revascularization over four years of follow-up. RESULTS: Procedural success rate was achieved in 84% and 95% (balloon angioplasty vs. stent, respectively). The increase in the minimal luminal diameter was greater in the stent group both after the intervention (2.02 +/- 0.6 mm vs. 1.43 +/- 0.6 mm in the angioplasty group; p < 0.0001), and at six-month follow-up (1.98 +/- 0.7 mm vs. 1.63 +/- 0.7 mm; p < 0.001). The corresponding restenosis rates were 22% and 37%, respectively (p < 0.002). After four years, no differences in mortality (2.7% vs. 2.4%) and nonfatal MI (2.2% vs. 2.8%) were found between the stent and the angioplasty groups, respectively. However, the requirement for further revascularization procedures of the target lesions was significantly reduced in the stent group (12% vs. 25% in the angioplasty group; relative risk 0.49, 95% confidence interval 0.32 to 0.75, p = 0.0006); most of the repeat procedures (84%) were carried out within six months of entry into the study. CONCLUSIONS: Patients who received an intracoronary stent showed a lower rate of restenosis than those treated with conventional balloon angioplasty. The benefit of stenting was maintained four years after implantation, as manifested by a significant reduction in the need for repeat revascularization.

Aged↗
PubMed1999

Tyrosine kinase-dependent ubiquitination of CD16 zeta subunit in human NK cells following receptor engagement.

We investigated whether aggregation of the low-affinity immunoglobulin G receptor (CD16) on human NK cells results in receptor ubiquitination. We found that the CD16 zeta subunit becomes ubiquitinated in response to receptor engagement. We then investigated whether protein tyrosine kinase (PTK) activation is required for CD16-mediated receptor ubiquitination. Pretreatment with the PTK inhibitor genistein substantially decreased ligand-induced zeta ubiquitination, suggesting a requirement for PTK activation in receptor ubiquitination. We further analyzed PTK involvement in controlling receptor ubiquitination by using the vaccinia virus expression system. Overexpression of wild-type active lck, but not a kinase-deficient mutant, enhanced both ligand-induced tyrosine phosphorylation and ubiquitination of the CD16 zeta subunit. Taken together, our data demonstrate that CD16 engagement induces zeta chain ubiquitination and strongly suggest a role for lck in regulating this modification.

Antigens, CD↗
PubMed1999

Visualisation of a paraganglioma by technetium-99m-sestamibi scintigraphy.

A 68-yr-old woman presented to our observation with multinodular goiter and a contiguous right laterocervical mass. In spite of ultrasound, technetium and iodine scan, CT and fine-needle biopsy, the precise origin of the mass remained uncertain. On additional multi-phase sestamibi scan, the neck region showed an early high uptake rapidly decreasing over time in the laterocervical mass, and a persistent inhomogeneous distribution in the thyroid gland. This behavior suggested that the laterocervical mass could derive from an anatomical structure other than the thyroid. Surgical exploration established the extrathyroid nature of the laterocervical mass and the histological examination confirmed that it was a typical paraganglioma. This finding is in keeping with a recent report of positive sestamibi uptake in a cervical paraganglioma, although our case showed a more rapid kinetic. This tumor should be therefore taken into consideration in the differential interpretation of focal sestamibi uptake.

Aged↗
PubMed1999

Effects on breathing of carotid body denervation in neonatal piglets.

The purpose of these studies was to test the hypothesis that carotid chemoreceptor activity is necessary for postnatal maturation of the ventilatory control system. By using a lateral surgical access, 17 piglets were carotid body denervated (CBD) and 14 were sham denervated at 3-25 days of age. After surgery, there was no irregular breathing in any group. There was no significant hypoventilation when CBD was performed at less than 5 days of age (n = 5) and only a mild (arterial PCO(2) 5 Torr; P < 0.05) to moderate, transient (arterial PCO(2) 8 Torr; P < 0.5) hypoventilation in piglets denervated at 10-15 (n = 6) and 20-25 (n = 6) days of age, respectively. Three weeks after surgery, both breathing of a hypoxic gas mixture and jugular venous NaCN injections elicited a hyperpnea in the CBD piglets that was attenuated compared with that in sham CBD piglets. In the CBD piglets, there was no response to injections of NaCN in the carotid arteries, but there was a response to NaCN injected into the proximal descending aorta, suggesting the residual peripheral chemosensitivity was of aortic origin. Carotid chemoreceptor-intact piglets had carotid and aortic NaCN chemosensitivity by 2 days of age. The carotid response persisted for the 40 days of the study, but the aortic reflex persisted only until approximately 8 days of age. We conclude that 1) the major effect of CBD per se in neonatal piglets is age-dependent hypoventilation and 2) there is a high degree of plasticity in peripheral chemosensitivity in neonates that may contribute to minimizing the changes in breathing after CBD.

Animals↗
PubMed1999

Cleavage of the ALL1 gene in acute lymphoid leukemia before treatment disappears in relapse.

BACKGROUND AND OBJECTIVE: ALL1 gene rearrangements are frequently found in secondary acute leukemias (ALs). A site-specific cleavage of the ALL1 gene in a consensus sequence for topoisomerase II recognition has been considered to be the initial step leading to ALL1 rearrangement and subsequent therapy-related AL. The aim of the present study was to evaluate this cleavage in our patients, to analyze whether it is a laboratory-produced artefact and to check whether it persists or causes a real ALL1 gene rearrangement at relapse. DESIGN AND METHODS: We studied ALL1 rearrangement in 74 cases of AL before treatment by Southern blot avoiding room temperature exposure or delay in processing the samples which could produce ALL1 cleavage. DNA was available for two cases with ALL1 cleavage; it was analyzed by three different Southern blots in one and two in the other. One case with ALL1 cleavage was also studied in relapse. RESULTS: The presence of the cleavage of the ALL1 DNA was found in 3 of 74 (4%) patients. Two of these three patients had the ALL1 cleavage in three and two different analyses. One case was positive for ALL1 cleavage at diagnosis, but negative for both ALL1 cleavage and ALL1 rearrangement at relapse. INTERPRETATION AND CONCLUSIONS: The fact that a constant pattern was obtained from the same patients in different DNA preparations, supports the notion that ALL1 cleavage is not a laboratory artefact. The absence of the cleavage in a sample from a relapsed patient suggests that the subclone with the ALL1 cleavage, in this case, did not play a clear role in the pathogenesis of disease recurrence.

Acute Disease↗
PubMed1998

Cerebral cortical blood flow in rabbits during parabolic flights (hypergravity and microgravity).

We studied the effect of gravity on cerebral cortical blood flow (CBF), mean arterial blood pressure (BPa) and heart rate in six rabbits exposed to parabolic flights. The CBF was obtained using a laser-Doppler probe fixed on to a cranial window. Before weightlessness, the animals were exposed to chest-to-back directed acceleration (1.8-2.0 g). The CBF values were expressed as a percentage of CBFo (mean CBF during 60 s before the 1st parabola). Propranolol (1 mg x kg[-1] i.v.) was given after the 11th parabola and pentobarbital (12-15 mg x kg[-1] i.v.) after the 16th parabola. Before the administration of the drugs, CBF increased (P < 0.01) during hypergravity [i.e. maximal CBF 151 (SD 64)% CBFo. Simultaneously BPa increased [maximal BPa, 119 (SD 11) mmHg (P < 0.01)]. At the onset of weightlessness, CBF and BPa reached maximal values [194 (SD 96)% CBFo (P < 0.01) and 127 (SD 19) mmHg, (P < 0.01) respectively]. The microgravity-induced increase in CBF was transient since CBF returned to its baseline value after 8 (SD 2) s of microgravity. After propranolol administration, CBF was not statistically different during hypergravity but an elevation of CBF was still observed in weightlessness. The increases in CBF and BPa also persisted during weightlessness after pentobarbital administration. These data would indicate that CBF of nonanesthetized rabbits increases during the first seconds of weightlessness and demonstrate the involvement of rapid active regulatory mechanisms since CBF returned to control values within 8 (SD 2) s. We concluded that this elevation in blood flow was not related to stress because it persisted after the administration of propranolol and pentobarbital.

Adrenergic beta-Antagonists↗
PubMed1998

[Growth hormone deficiency. Treatment with growth hormone and body composition].

Increased fat mass, decreased lean mass, muscular mass and bone mineral density are characteristic of the body composition in GH deficiency, GH treatment reverses these abnormalities. Body composition was determined in 20 young adults with GHD diagnosed in childhood, whose GH treatment was stopped 1 year earlier. Reevaluation of GH secretion in these patients showed that 12 remained GH deficient (confirmed GHD) while eight recovered normal GH secretion (transient GHD). One year after stopping the GH treatment, patients with confirmed GHD showed an increased fat mass as compared with value at the end of the treatment; in addition a decreased bone mineral content was observed in the patients with low physical activity. There was no increased fat mass in transient GHD; however, these patients presented with low bone mineral content, as previously reported in adults with history of delayed growth and adolescence.

Adolescent↗
PubMed1998

P230 BCR/ABL protein may be associated with an acute leukaemia phenotype.

The BCR/ABL rearrangement, the molecular hallmark of chronic myelogenous leukaemia (CML), is rare in acute myeloid leukaemia (AML), being detected in approximately 1% of cases. In the vast majority of CML cases the breakpoint on chromosome 22 falls in the so-called major breakpoint cluster region of the BCR gene. Only a few cases of CML with breakpoint in the minor or in the micro bcr region have so far been reported. The micro breakpoint position has been associated mainly with a mild form of CML, defined as Philadelphia chromosome-positive chronic neutrophilic leukaemia (Ph-positive CNL). Using reverse transcription-polymerase chain reaction (RT-PCR) we report a patient with an acute myeloid leukaemia phenotype at diagnosis who showed a BCR/ABL rearrangement with a breakpoint located in the micro bcr region (e19a2 junction). Cytogenetic analysis showed a progression of the malignant clone, finally leading to cells with two Ph chromosomes, trisomy 8, isochromosome 17q and deletion of the long arms of chromosome 7. The findings of chromosomal changes point to a possibility of blast crisis of CML with a clinically silent chronic phase. Immunoprecipitation and auto-phosphorylation assay revealed the expression, by the patient's blast cells, of an abnormal P230 BCR/ABL protein, which showed for the first time that this protein was constitutively activated in primary cells from patients. This finding may contribute to the understanding of the role of the BCR/ABL rearrangements in determining different leukaemia phenotypes ranging from acute lymphoid and myeloid leukaemias to mild chronic neutrophilic leukaemias.

Acute Disease↗
PubMed1998

Cutaneous involvement as the first manifestation in a case of T-cell prolymphocytic leukaemia.

Mature T-cell malignancies of extracutaneous origin are rare disorders. T-cell prolymphocytic leukaemia (T-PLL) is the most common form of all mature T-cell leukaemias in adults. Secondary skill involvement by T-PLL has been reported in 25% of patients. A case of T-PLL which presented with cutaneous infiltration mimicking a cellulitis-like lesion resistant to antibiotic therapy is described. The diagnosis of T-PLL was subsequently fully supported by the clinical, laboratory and cytological findings, as well as by the immunophenotypic study of the skin biopsy. The present case stresses the importance of accurate evaluation of skin lesions in the diagnosis of some haematological conditions and gives additional information about T-PLL such as a previously non-reported cytogenetic abnormality [t(6;6)] and lack of cutaneous lymphocytic-associated antigen expression.

Aged↗
PubMed1998

Molecular basis of open-angle glaucoma in Italy.

Glaucoma is a group of ocular diseases characterized by an optic neuropathy in which degeneration of retinal ganglion cells leads to a characteristic excavation of the optic nerve head. Primary open-angle glaucoma (POAG) can be subdivided into two groups according to age of onset:- 1. the more common middle- to late-age onset, chronic open-angle glaucoma (COAG) diagnosed after the age of 40 years; 2. the rarer juvenile open-angle glaucoma (JOAG), which is diagnosed between the age of 3 years and early adulthood. Recently, the gene coding for the trabecular meshwork-induced glucocorticoid response protein (TIGR), located in chromosome 1 (1q23-25), was found mutated in patients affected by POAG. In this work we describe the clinical and molecular genetic features of several Italian families affected by autosomal dominant POAG, collected in various regions of Italy.

Adult↗
PubMed1998

Blue-yellow perimetry in patients with ocular hypertone.

The authors report the data of the blue-yellow (B-Y) perimetry compared with the Standard perimetry in normal subjects with endocular hypertension or with initial glaucoma. With the aim of evaluating the relationship with chromatic sense deficits, precociously found in glaucoma, the F-M 100 Hue test and Lanthony D 15 Desaturé test were done. Checks were made of refraction, visual acuity, pupil diameter and assumption of medications. Sensitivity reduction in eyes with initial glaucoma is highly significant with the B-Y perimetry. Pupil diameter reduction is quite uninfluential while the chromatic sense shows some quantitative and qualitative deficits.

Adult↗
PubMed1998

Important role of carotid afferents in control of breathing.

The purpose of the present study was to determine the effect on breathing in the awake state of carotid body denervation (CBD) over 1-2 wk after denervation. Studies were completed on adult goats repeatedly before and 1) for 15 days after bilateral CBD (n = 8), 2) for 7 days after unilateral CBD (n = 5), and 3) for 15 days after sham CBD (n = 3). Absence of ventilatory stimulation when NaCN was injected directly into a common carotid artery confirmed CBD. There was a significant (P < 0.01) hypoventilation during the breathing of room air after unilateral and bilateral CBD. The maximum PaCO2 increase (8 Torr for unilateral and 11 Torr for bilateral) occurred approximately 4 days after CBD. This maximum was transient because by 7 (unilateral) to 15 (bilateral) days after CBD, PaCO2 was only 3-4 Torr above control. CO2 sensitivity was attenuated from control by 60% on day 4 after bilateral CBD and by 35% on day 4 after unilateral CBD. This attenuation was transient, because CO2 sensitivity returned to control temporally similar to the return of PaCO2 during the breathing of room air. During mild and moderate treadmill exercise 1-8 days after bilateral CBD, PaCO2 was unchanged from its elevated level at rest, but, 10-15 days after CBD, PaCO2 decreased slightly from rest during exercise. These data indicate that 1) carotid afferents are an important determinant of rest and exercise breathing and ventilatory CO2 sensitivity, and 2) apparent plasticity within the ventilatory control system eventually provides compensation for chronic loss of these afferents.

Afferent Pathways↗
PubMed1998

A common beta ig-h3 gene mutation (delta f540) in a large cohort of Sardinian Reis Bücklers corneal dystrophy patients. Mutations in brief no. 180. Online.

Reis-Bücklers' corneal dystrophy (RBCD) is a relatively rare autosomal dominant disease originating in the Bowman's membrane, which causes severe visual impairment. Recently RBCD, together with lattice corneal dystrophy type I (LCDI), granular corneal dystrophy (CDGG1) and Avellino stromal dystrophy (ASD), all mapped on 5q31, were found to be associated to four different mutations in the beta ig-h3 gene which codify for kerato-epithelin. We identified several cases of RBCD in Sardinia. We reconstructed through genealogical search two eight generation-families, originating from the same village (Arbus), indicating a common ancestor for RBCD in Sardinia. Linkage studies on these families confirmed the association of the disease with the 5q31 region. Sequence analysis of beta ig-h3 gene revealed a trinucleotide deletion in exon 12, corresponding to the loss of F540 in the protein sequence (delta F540). Our data describe a new mutation in the beta ig-h3 gene causing RBCD. This dominant negative mutation is located in the fourth internal repeat of kerato-epithelin which is a protein domain highly conserved across species. This suggests the basic role of this domain in maintaining the proper kerato-epithelin structure which when altered can cause the typical precipitates in the RBCD cornea.

Chromosomes, Human, Pair 5↗