Biomedical subjects

A Bianchi

Publications and source records attributed to A Bianchi.

At least 109 records · Page 6Linked to original sources

PubMed2000

Stapes surgery and psychiatric complications.

Changes in auditory perception can cause disturbances in development and personality. This phenomenon has been studied in particular in children hearing loss or in progressive or sudden hearing loss in the adult. We present the case of a patient with psychobehavioural alterations after restoration of hearing following a small fenestra stapedectomy for bilateral otosclerosis with moderate-severe hearing impairment. The diagnosis, physiopathology and medicolegal implications are discussed.

Female↗

PubMed2000

The impact of cyclic alternating pattern on heart rate variability during sleep in healthy young adults.

OBJECTIVE: Cyclic alternating pattern (CAP) consists of arousal-related phasic events while the complementary condition, non-CAP (NCAP), is characterized by a rhythmic background activity, reflecting a condition of stable arousal, during non-REM sleep. The arousal swings that accompany the appearance of CAP on the EEG are associated with transient variations of muscle tone and autonomic activities, including heart rate (HR). The aim of our study was to evaluate HR variability in relation to CAP during non-REM sleep in healthy adults. METHODS: Ten healthy subjects (mean age = 28.1 years) underwent 8 h polysomnography. HR variations were measured by power spectrum analysis. The ECG signals were segmented in correspondence of the different sleep stages and different CAP conditions. RESULTS: A significant difference between CAP and NCAP conditions was found in low frequency (LF) component (increased in CAP) and high frequency (HF) component (decreased in CAP). LF/HF ratio was increased in CAP. CONCLUSION: Physiological fluctuations of the EEG arousal level influence cardiac autonomic activity in normal subjects. The studies on nocturnal variation in sympathetic and vagal tone should take in account the microstructural sleep changes, other than the conventional polysomnographic parameters.

Activity Cycles↗

PubMed2000

Teicoplanin biosynthesis genes in Actinoplanes teichomyceticus.

The genetic determinants for the biosynthesis of the glycopeptide antibiotic teicoplanin were identified. In order to isolate the corresponding gene cluster, oligonucleotides derived from highly conserved motifs in peptide synthetases were used. These synthetic probes, and gene fragments derived from the balhimycin gene cluster of Amycolatopsis mediterranei, led to the identification of the likely teicoplanin gene cluster centered on a region of ca. 110 kb from the genome of Actinoplanes teichomyceticus, the teicoplanin producer. Partial nucleotide sequences identified partial ORFs likely to encode two glycosyltransferases, three P-450 monooxygenases and one ABC transporter. The corresponding genes have been found in other glycopeptide gene clusters. Furthermore, upstream to the peptide synthetase region a segment was identified with a remarkable similarity to the vanHAX operon, conferring resistance to glycopeptides in enterococci. Thus, in contrast to the other glycopeptide producers thus far analyzed, in A. teichomyceticus the genes for teicoplanin biosynthesis are closely linked to homologs of glycopeptide resistance commonly found in vancomycin-resistant enterococci.

Actinomycetales↗

PubMed2000

Effects of the chemokine stromal cell-derived factor-1 on the migration and localization of precursor-B acute lymphoblastic leukemia cells within bone marrow stromal layers.

Acute lymphoblastic leukemia (ALL) blasts undergo migration into layers of bone marrow fibroblasts (BMF) in vitro, utilizing the beta1 integrins VLA-4 and VL-5 as adhesion molecules. However, it has been unclear as to whether this is a selective process mediated by specific chemoattractant molecules, or simply a reflection of the highly motile nature of early B cell precursors. We further characterized this process using a transwell culture system, in which the two chambers were separated by an 8 microm diameter microporous membrane, through which leukemic cells could move. When a BMF layer was grown on the upper surface of the membrane there was an 84.1% reduction in transmigration of the human pre-B ALL cell line NALM-6 into the lower chamber, compared to control membrane with no BMF layer. Localization of leukemic cells under the BMF layer was confirmed ultrastructurally, suggesting the possibility that the migration of leukemic cells was directed by a chemotactic agent secreted by BMF. The involvement of the chemokine stromal cell-derived factor-1 (SDF-1) in this process was next investigated. BMF were shown to express m-RNA for SDF-1. Addition of SDF-1 at 100 ng/ml into the lower chamber increased transmigration of NALM-6 across the membrane by 2.2-fold, and also induced a 1.4- to 6.1-fold increase in movement of NALM-6 through a BMF layer into the lower chamber. The receptor for SDF-1, CXCR4, was demonstrated by flow cytometry on all 10 cases of precursor-B ALL analyzed, as well as on NALM-6, KM-3 and REH lines. An inhibitory antibody to CXCR4 was able to block the migration of NALM-6 cells into BMF monolayers grown on plastic by 51%, and in nine cases of ALL by 8-40%, as well as partially inhibit transmigration of leukemic cells through BMF layers along an SDF-1 concentration gradient. These results confirm that precursor-B ALL cells selectively localize within bone marrow stroma in vitro, and that this process is partially due to the stromal chemokine SDF-1 binding to its receptor CXCR4 on leukemic cells. SDF-1 may be important in influencing the localization of precursor-B ALL cells in marrow microenvironmental inches which regulate their survival and proliferation.

Bone Marrow↗

PubMed2000

Increased expression of non-functional killer inhibitory receptor CD94 in CD8+ cells of myeloma patients.

Different MHC class I-specific killer inhibitory receptors (KIRs) are expressed in vivo by a minor fraction of activated memory CD8+ cells. It has been postulated that KIRs may 'fine-tune' specific responses by altering their threshold of activation by the TCR-CD3 complex. We have previously shown that, in multiple myeloma (MM) patients, a large fraction of peripheral blood CD8+ cells display the phenotype of chronically activated memory T cells (CD38+, HLA-DR+, CD25-, CD45R0+, CD28-). We investigated the expression of KIRs on MM T cells and determined their possible influence on cytolytic responses elicited via the CD3-TCR complex. The expression of CD94, a molecule that is part of a heterodimeric KIR recognizing the non-classical MHC surface HLA-E molecule, was almost threefold higher in MM T cells than in age-matched normal control subjects (P < 0.0001). CD94 expression was preferentially confined to CD8+ cells but not restricted to activated (HLA-DR+) and/or memory (CD45R0+) T cells. Unlike normal T cells, in which CD94 is assembled with glycoproteins of the NKG2 family to form functional receptors with activating or inhibitory properties, most CD94+ MM T cells were devoid of both the NKG2-A and NKG2-C glycoproteins detected in the inhibitory or activating form respectively. CD94 blockade did not significantly affect either T-cell proliferation or cytotoxic T-lymphocyte generation induced by the myeloma-derived cell lines NCI and RPMI 8226. Similarly, the cytolytic activity induced by direct anti-CD3-mediated targeting of MM T cells to FCR+ P815 target cells was unaffected by the addition of anti-CD94 and/or anti-NKG2-A/C monoclonal antibodies (mAbs). These data indicate that the large majority of MM CD8+ cells do not express a functional CD94 receptor. Thus, their ability to 'fine-tune' an appropriate immune response against tumour cells can be impaired.

Antibodies, Monoclonal↗

PubMed2000

The anterior mediastinal approach for management of tracheomalacia.

BACKGROUND: Tracheomalacia occurs as a primary developmental defect or may be secondary to vascular compression. It is common in association with esophageal atresia and tracheoesophageal fistula. Collapse of the weak trachea is a cause of recurrent respiratory symptoms but may be severe and life threatening. METHODS: Between 1978 and 1999 at Sheffield Children's Hospital and The Royal Manchester Children's Hospital, of 16 children with clinically significant symptoms of tracheomalacia 8 underwent combined aortopexy and tracheopexy, 1 had aortopexy alone, 4 only had a tracheopexy, and 3 had tracheal reinforcement with free costal cartilage ring grafts. The surgical approach was limited to a low cervical skin crease incision with a midline manubrial split providing extrapleural access to the anterior mediastinum and allowing for all surgery under direct unimpaired vision. RESULTS: Ten children did not require postoperative ventilatory support. Four underwent ventilation for a few hours or days. One child required CPAP for 4 months for residual tracheomalacia and a further child, who had 3 operations to insert 11 costal cartilage ring grafts, underwent ventilation intermittently for 6 months. Adequate tracheal patency could be verified by intraoperative tracheoscopy and was sustained postoperatively so that only 1 child with associated bilateral vocal cord paralysis came to tracheostomy. Four children required prolonged hospitalization because of residual tracheomalacia, 2 for bronchomalacia and 2 because of esophageal narrowing leading to further surgery. All other children were fit for discharge within 10 to 30 days of surgery. Long-term follow-up has confirmed sustained tracheal improvement and resolution of the life-threatening features of tracheomalacia. CONCLUSIONS: The authors recommend the low skin crease transmanubrial approach, as described by Vaishnav and MacKinnon, for tracheopexy, aortopexy and for tracheal reconstruction for tracheomalacia. The approach gives excellent access for surgery under direct vision through a relatively avascular plane. It is associated with less morbidity than a conventional thoracotomy and leaves a more acceptable aesthetic scar.

Child, Preschool↗

PubMed2000

The contemporary outcome of gastroschisis.

BACKGROUND: The aim of this study was to evaluate the contemporary outcome in the management of gastroschisis. METHODS: A retrospective analysis was conducted of 91 babies admitted over a 7-year period to a single neonatal surgical unit with a diagnosis of gastroschisis. RESULTS: An antenatal diagnosis was made in 89 (98%) cases. Surgical intervention occurred in 90 babies, at a mean of 5 hours (range, 0.5 to 17) postdelivery. In 72 (80%) cases, primary closure of the abdominal defect was achieved, with a silo fashioned in the remaining 18 (20%). One child died before abdominal closure. The median time to full oral feeding was 30 days (range, 5 to 160 days), and to discharge was 42 days (range, 11 to 183 days). Those children who required a silo, took longer to feed (P =.008) and stayed longer in the hospital (P =.021). The 8 (8.8%) children with an intestinal atresia, required significantly more operative procedures (P =.0001) and took significantly longer to achieve full oral feeding (P =.04), but the presence of an atresia was not an independent risk factor for mortality. There were 7 deaths (7.7%), 3 within the first 7 days. Of the deaths, 5 (71%) were caused by overwhelming sepsis. CONCLUSIONS: The contemporary mortality rate from gastroschisis is less than 8%, and minimizing septic complications would contribute significantly to reducing this. Strategies designed to improve morbidity must focus on optimizing management of those factors associated with a prolonged recovery, namely intestinal atresia, prematurity, and the use of a silo.

Birth Weight↗

PubMed2000

Role of food intake in the modulation of hexarelin-induced growth hormone release in normal human subjects.

Hexarelin (HEX) is a new synthetic analog of the Growth Hormone releasing peptides and is stronger than GHRH in releasing GH in vivo. No information is available on the effect of food ingestion on HEX-induced GH secretion. On the other hand, we have previously demonstrated that food intake at lunchtime in normal subjects has an inhibitory effect on the GH response to GHRH. The aim of the present study was to investigate the effect of food ingestion on GH secretion induced by HEX as compared to GHRH in six normal men (aged 23-29 years) and six normal women (aged 24-29 years). The body weights for all subjects were within 120% of their ideal body weight, according to their sex and age. Our data confirm that HEX is much more powerful than GHRH in inducing GH release in humans, both in the fasting state (GH-AUC: 3010 +/- 695 after HEX, vs. 1339 +/- 281 after GHRH, microg/L/120 min; p<0.06) and after a meal (GH-AUC: 1523 +/- 121, after HEX, vs. 309 +/- 61, after GHRH, microg/L/120 min; p<0.06). Moreover, our study shows that food intake partially blunts the fasting GH response to HEX (GH-AUC: 3010 +/- 695 after HEX, in fasting state, vs. 1523 +/- 121 after HEX, after meal, microg/L/120 min; p<0.06; mean inhibition of AUC 41.02 +/- 7.96%), whereas it nearly abolishes the GH response to GHRH in the same subjects (GH-AUC: 1339 +/- 281 after GHRH, in fasting state, vs. 309 +/- 61 after GHRH, after meal, microg/L/120 min; p<0.06; mean inhibition of AUC 70.31 +/- 6.22%). In conclusion, our study confirms that HEX acts differently from GHRH; the GH releasing effect of HEX could be only partially influenced by the physiological metabolic or neuroendocrine food-related modifications.

Adult↗

PubMed2000

In vitro inactivation of Chlamydia trachomatis and of a panel of DNA (HSV-2, CMV, adenovirus, BK virus) and RNA (RSV, enterovirus) viruses by the spermicide benzalkonium chloride.

Kinetics of inactivation by the detergent spermicide benzalkonium chloride (BZK) of Chlamydia trachomatis and of a panel of DNA viruses [herpes simplex virus hominis type 2 (HSV-2), cytomegalovirus (CMV), adenovirus (ADV) and BK virus (BKV)] and RNA [respiratory syncytial virus (RSV) and enterovirus (ENV)] were established in accordance with a standardized in vitro protocol. After a 5 min incubation, inactivation of >95% of HSV-2 and CMV was obtained at a concentration of 0.0025% (w/v) (25 Ig/L); concentrations as low as 0.0005%, 0.0050% and 0.0125%, induced a 3.0 log10 reduction in infectivity of HSV-2 and CMV, RSV and ADV, respectively. After a 60 min incubation, concentrations of 0.0125% and 0.050% provided a 3.0 log10 reduction in infectivity of ENV and BKV, respectively. These features indicate that sensitivity to BZK was very high (HSV-2 and CMV) or high (RSV) for enveloped viruses, intermediate (ADV) or low (ENV and BKV) for non-enveloped viruses. Furthermore, BZK had marked antichlamydial activity, showing >99% killing after only a 1 min incubation at a concentration of 0.00125%. BZK demonstrates potent in vitro activity against the majority of microorganisms causing sexually transmitted infectious diseases, including those acting as major genital cofactors of human immunodeficiency virus transmission. These attributes qualify BZK as a particularly attractive candidate for microbicide development.

Adenoviridae↗

PubMed2000

Prediction of difficult mask ventilation.

BACKGROUND: Maintenance of airway patency and oxygenation are the main objectives of face-mask ventilation. Because the incidence of difficult mask ventilation (DMV) and the factors associated with it are not well known, we undertook this prospective study. METHODS: Difficult mask ventilation was defined as the inability of an unassisted anesthesiologist to maintain the measured oxygen saturation as measured by pulse oximetry > 92% or to prevent or reverse signs of inadequate ventilation during positive-pressure mask ventilation under general anesthesia. A univariate analysis was performed to identify potential factors predicting DMV, followed by a multivariate analysis, and odds ratio and 95% confidence interval were calculated. RESULTS: A total of 1,502 patients were prospectively included. DMV was reported in 75 patients (5%; 95% confidence interval, 3.9-6.1%), with one case of impossible ventilation. DMV was anticipated by the anesthesiologist in only 13 patients (17% of the DMV cases). Body mass index, age, macroglossia, beard, lack of teeth, history of snoring, increased Mallampati grade, and lower thyromental distance were identified in the univariate analysis as potential DMV risk factors. Using a multivariate analysis, five criteria were recognized as independent factors for a DMV (age older than 55 yr, body mass index > 26 kg/m2, beard, lack of teeth, history of snoring), the presence of two indicating high likelihood of DMV (sensitivity, 0.72; specificity, 0.73). CONCLUSION: In a general adult population, DMV was reported in 5% of the patients. A simple DMV risk score was established. Being able to more accurately predict DMV may improve the safety of airway management.

Adult↗

PubMed2000

Hemimandibular hyperplasia: treatment strategies.

Hemimandibular hyperplasia is a well-defined, rare asymmetrical mandibular malformation. It is characterized by diffuse enlargement of the condyle, the condylar neck, and the ramus and body of the mandible. Because the anomaly begins before puberty, it is understandable that the maxilla follows the downward growth of the mandible. Pathogenesis is due most likely to clear hyperactivity in the condyle, which can be documented histologically with an actively proliferating cartilage. Therapy is largely based on the patient's age. The authors present their series of nine individuals with hemimandibular hyperplasia treated with various surgical methods between 1992 and 1994. A therapeutic approach called orthopedic maxillary management applied to two of the nine patients is presented. The objective is to maintain the occlusal maxillary plane in a correct position in growing patients. All clinical results, except one, were satisfying and showed good postoperative stability.

Adolescent↗

PubMed2000

Control of human telomere length by TRF1 and TRF2.

Telomere length in human cells is controlled by a homeostasis mechanism that involves telomerase and the negative regulator of telomere length, TRF1 (TTAGGG repeat binding factor 1). Here we report that TRF2, a TRF1-related protein previously implicated in protection of chromosome ends, is a second negative regulator of telomere length. Overexpression of TRF2 results in the progressive shortening of telomere length, similar to the phenotype observed with TRF1. However, while induction of TRF1 could be maintained over more than 300 population doublings and resulted in stable, short telomeres, the expression of exogenous TRF2 was extinguished and the telomeres eventually regained their original length. Consistent with their role in measuring telomere length, indirect immunofluorescence indicated that both TRF1 and TRF2 bind to duplex telomeric DNA in vivo and are more abundant on telomeres with long TTAGGG repeat tracts. Neither TRF1 nor TRF2 affected the expression level of telomerase. Furthermore, the presence of TRF1 or TRF2 on a short linear telomerase substrate did not inhibit the enzymatic activity of telomerase in vitro. These findings are consistent with the recently proposed t loop model of telomere length homeostasis in which telomerase-dependent telomere elongation is blocked by sequestration of the 3' telomere terminus in TRF1- and TRF2-induced telomeric loops.

Cell Line↗

PubMed2000

Induced sputum cellularity. Reference values and distribution in normal volunteers.

Sputum induction has recently been proposed as the only direct noninvasive method for measuring airway inflammatory indices. The reference values and the distribution of cells in induced sputum in a control population have not yet been well defined. We therefore evaluated data from a large number of healthy volunteers. One hundred fourteen healthy, nonatopic, nonsmoking volunteers without airway hyperreactivity were enrolled (age: 38 +/- 13 yr [mean +/- SD]; FEV(1): 105 +/- 10% predicted; provocative dose of methacholine inducing a 20% decrease FEV(1) > 3,200 microgram). Ninety-six subjects (84%) produced adequate analysis samples. The subjects had a normal age distribution. Their induced sputum was rich in macrophages (69.2 +/- 13%) and neutrophils (27.3 +/- 13%), and poor in eosinophils (0.6 +/- 0.8%), lymphocytes (1.0 +/- 1.2%), and epithelial cells (1.5 +/- 1.8%). Only macrophages and neutrophils showed a normal distribution; total and differential counts of other cells did not. We propose that these data be used in comparison of the induced sputum cells of normal subjects and those of patients with airway inflammation.

Adult↗

PubMed2000

Differential expression of peroxisome proliferator-activated receptors (PPARs) in the developing human fetal digestive tract.

We investigated the spatiotemporal distributions of the different peroxisome proliferator-activated receptor (PPAR) isotypes (alpha, beta, and gamma) during development (Week 7 to Week 22 of gestation) of the human fetal digestive tract by immunohistochemistry using specific polyclonal antibodies. The PPAR subtypes, including PPARgamma, are expressed as early as 7 weeks of development in cell types of endodermal and mesodermal origin. The presence of PPARgamma was also found by Western blotting and nuclease-S1 protection assay, confirming that this subtype is not adipocyte-specific. PPARalpha, PPARbeta, and PPARgamma exhibit different patterns of expression during morphogenesis of the digestive tract. Whatever the stage and the gut region (except the stomach) examined, PPARgamma is expressed at a high level, suggesting some fundamental role for this receptor in development and/or physiology of the human digestive tract.

Antibody Specificity↗

PubMed2000

A retrospective analysis of postradiation chemotherapy in 133 patients with glioblastoma multiforme.

The impact on survival of postradiation nitrosourea-containing chemotherapy (CHT) in patients with glioblastoma multiforme (GM) was analyzed retrospectively in 133 patients who completed the planned radiotherapy out of 173 observed cases. Thirty-five patients were < 50 years old, 89 were males, 20 had performance status (PS) < 70 and 72 > or = 70. Surgery was followed by radiotherapy in all cases (50-60 Gy in 95 patients, 61-70 Gy in 38 patients). At the end of radiotherapy, 43 patients received CHT, whereas 90 patients did not receive further therapy. At univariate analysis, age < 50 years, feminine gender, subtotal or total resection, radiotherapy doses > 60 Gy, and CHT had an independent prognostic value. Our results suggest that chemotherapy improves 2-year survival rates from 12% to 28% in GM. The sequence of treatment, new drugs, and combinations should be further explored.

Adult↗

PubMed2000

Inhibitory action on GHRH-induced GH secretion of chronic tamoxifen treatment in breast cancer.

OBJECTIVE: Previous in vitro and in vivo studies on animal models have demonstrated that tamoxifen (TAM) inhibits GH secretion. Studies in humans are conflicting. The aim of this study was to evaluate the effect of chronic TAM treatment on GH secretory dynamics in the presence of negligible endogenous oestrogens, in postmenopausal women with breast cancer. PATIENTS: Ten female patients were studied over a 6-12-month period after surgical therapy, before medical therapy, and during chronic treatment with TAM (20 mg/day p.o.). MEASUREMENTS: In all subjects we performed a standard GHRH-test (50 mg i.v. as a bolus) and compared the single time points, the peak response and the areas under the curves (AUC), before and during treatment. In basal samples, we evaluated the circulating levels of IGF-1, IGF-BP3 and their ratio, SHBG, FSH, LH, Oestradiol (E2) and PRL. GH was assayed by Immunoradiometric assay (IRMA). Insulin-like growth factor type I (IGF-I), Insulin-like growth factor-binding protein-3 (IGF-BP3), FSH, LH and PRL were measured by Radioimmunoassay (RIA). SHBG was measured by a noncompetitive liquid phase immunoradiometric assay, while E2 was measured directly in plasma by a liquid phase technique. RESULTS: TAM chronic treatment significantly reduced GH response to GHRH at single time point evaluations, GH peak response (mean decrease: 59.8 +/- 7.3%) and GH-AUC (mean decrease 53.8 +/- 8.9%). TAM also significantly reduced plasma IGF-1 levels. No significant variations were found in IGF-BP3 levels or in the IGF-1/IGF-BP3 ratio. A significant inverse correlation between SHBG and IGF-1 circulating levels was noticed during TAM treatment. CONCLUSIONS: Our data show that long-term tamoxifen treatment blocks the response of GH to exogenous GHRH and reduces IGF-1 levels, possibly by a central mechanism other than the demonstrated peripheral action. The results of this study, keeping in mind the demonstrated mitogenic role of IGF-1 in cancer proliferation, can contribute to clarify the mechanism by which TAM exerts its antiproliferative effect.

Aged↗

PubMed2000

Serious hematoma of the vulva from a bicycle accident. A case report.

BACKGROUND: Vulvar hematomas may be caused by obstetric, athletic or sexual trauma or by car or bicycle accidents. CASE: A 29-year-old woman presented with a serious vulvar hematoma caused by a straddle bicycle accident. Monitoring of the hematologic parameters showed progressive anemia resulting from silent bleeding, which required surgical evacuation of the hematoma and complete hemostasis. CONCLUSION: The rich vulvar vascular network may be easily damaged by contusive frontal impacts, which crush the vulvar tissues against the osseous planes. Management of vulvar hematomas may range from conservative to surgical. Drainage and incision are advised in more severe cases to reduce infective complications and hospitalization.

Adult↗

PubMed2000

Implications of peroxisome proliferator-activated receptors (PPARS) in development, cell life status and disease.

The past several years have seen an increasing interest in the peroxisome proliferator-activated receptors (PPARs). These transcriptional factors belong to the superfamily of the steroid/thyroid/retinoid receptors. They are activated by fatty acids or their metabolites as well as by different xenobiotic peroxisome proliferators. These receptors are expressed in both the embryo and the adult organism. They have been implicated in cell proliferation, differentiation and apoptosis. In this review, we will attempt to point out some of the more salient features of this expression pattern during development and the different steps of cell life. The current understanding of how PPARs are involved in some human diseases will also be described.

Animals↗