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Biomedical subjects

D Costa

Publications and source records attributed to D Costa.

At least 19 recordsLinked to original sources
PubMed1997

Brachycephaly is ineffective for detection of Down syndrome in early midtrimester fetuses.

The aim of this study was to assess the value of fetal brachycephaly in the detection of Down syndrome at 13-18 weeks of pregnancy. The cephalic index (CI) was determined in 555 consecutive chromosomally normal fetuses, and in 38 chromosomal abnormalities, prior to amniocentesis. A CI > 0.85 was observed in 14% (2/14) of the fetuses with Down syndrome and in 11% of the normal fetuses. In conclusion, our data show that brachycephaly is not a useful marker for Down syndrome in early midtrimester fetuses.

Adolescent↗
PubMed1997

Interobserver variability of midtrimester fetal nuchal thickness.

OBJECTIVE: To assess the interobserver variability of ultrasound measured fetal nuchal thickness (NT). STUDY DESIGN: NT was measured in 103 consecutive early midtrimester pregnancies (13-18 weeks) by three ultrasonographists with different levels of expertise, in our Prenatal Unit. Measurements were obtained prior to amniocentesis, blindly in relation to other examiners' values. The Lin's concordance correlation coefficient and the Kappa statistics were used to assess concordance between observed values. RESULTS: Mean differences between pairs of observers ranged from 0.44 to 0.57 mm. A higher concordance correlation between measurements was obtained between the more experienced observers (r = 0.77 versus r = 0.51). When assigning cases with a NT > or = 5 mm to a group at risk for Down's syndrome, a high concordance between experienced ultrasonographists was observed (98% agreement; kappa = 0.90). CONCLUSIONS: Interobserver variability in NT was acceptable between experienced ultrasonographists.

Adult↗
PubMed1997

Thrombosis and restenosis after peripheral angioplasty: does acute 111indium-platelet accumulation predict angioplasty outcome?

OBJECTIVES: Use of platelet deposition to predict failure following angioplasty. DESIGN: Prospective study of angioplasty patients in a 9 months surveillance period. MATERIALS: Thirty-eight successful angioplasty patients. METHODS: Autologous 111indium-labelled platelets were re-injected immediately after angioplasty. Gamma camera and probe measures of radioactivity were obtained daily for 2-4 days and compared to a reference site to obtain a radioactivity ratio. Patient follow up was with duplex and arteriography from day 0 to 9 months or at angioplasty failure. RESULTS: Thirty-one patients remained asymptomatic; two developed acute occlusion and five developed restenosis. Platelet accumulation (increased mean radioactivity ratio) occurred at all angioplasty sites and was significantly higher after acute occlusion (camera: 2.93 and probe: 1.93) compared to asymptomatic patients (camera: 1.25 and probe: 1.15) and restenotic patients (camera: 1.31 and probe: 1.23). Radioactivity ratio was not different in patients who later developed restenosis. CONCLUSION: 111Indium platelet radioactivity effectively detected acute angioplasty reocclusions, but was unable to predict subsequent angioplasty restenosis.

Adult↗
PubMed1997

Criteria for fetal nuchal thickness cut-off: a re-evaluation.

An attempt has been made to establish a more effective cut-off criterion for nuchal thickness (NT) and to assess the optimal gestational period for the prediction of trisomies 21 and 18. Reference intervals were established for NT from the tenth to the 18th week, using either gestation-specific centiles or the parametric method. The measurements in 47 consecutive trisomy 21 and 18 trisomy 18 cases were plotted against these intervals. Assaying different cut-off criteria for both the centile and the parametric methods, sensitivities and false-positive rates for each gestational week were calculated and then compared with the commonly applied 'two-stepped' cut-off method (3 mm early, 6 mm later). The parametric method, based on a progressive rise, with +2.5 SD for the corresponding gestational week as a cut-off value, showed the best performance (likelihood ratio 38) in the prediction for trisomy 21. The optimal gestational age was the 12-18 week period, with an overall sensitivity of 62 per cent (23/37) for an average false-positive rate of 0.7 per cent. For trisomy 18, the most effective cut-off was also +2.5 SD, and 10-13 gestational weeks as the optimal period, achieving 86 per cent (6/7) sensitivity for a 1.9 per cent false-positive rate.

Chromosome Aberrations↗
PubMed1996

Early midtrimester fetal nuchal thickness: effectiveness as a marker of Down syndrome.

OBJECTIVE: Our purpose was to assess the validity of nuchal thickness in the prediction of Down syndrome in early midtrimester fetuses. STUDY DESIGN: In 1543 consecutive pregnancies undergoing amniocentesis, primarily for advanced maternal age, nuchal thickness was prospectively measured between 13 and 18 weeks and then correlated with the karyotype obtained from amniotic fluid. RESULTS: With the cutoff value suggested in the literature (> or = 6 mm), 33.3% (6/18) of the cases of Down syndrome would be detected for a 0.1% (2/1424) false-positive rate, with a positive predictive value adjusted to a prevalence of Down syndrome in the general population of 1:3. To increase the sensitivity of the method, the threshold was lowered to 5 mm, achieving a sensitivity of 77.8% (14/18) for a 2.1% (30/1424) false-positive rate and an adjusted positive value of 1:19. CONCLUSIONS: In early midtrimester fetuses decreasing the nuchal thickness threshold to 5 mm substantially enhances the detection of Down syndrome with a reasonable false-positive rate.

Down Syndrome↗
PubMed1996

The significance of increased 111indium platelet accumulation at post-angioplasty sites.

We assessed prospectively the significance of 111indium labelled platelet accumulation following angioplasty procedures in 12 patients (9 femoral angioplasties (2 laser, 1 atherectomy) and 3 iliac stents). Autologous 111indium labelled platelets were re-injected immediately after angioplasty. Radioactivity was measured over treated and reference sites, by single probe and gamma camera, and expressed as a radioactivity ratio (RR). All patients had duplex ultrasound assessment and occlusions were confirmed by arteriography. RR was always raised after angioplasty. Three patients who had acute occlusions showed markedly raised average RRs (significant at 99% ANOVA). RR was not raised after laser assisted angioplasty, however, our numbers were small. 111Indium platelet radioactivity did not predict subsequent occlusion after angioplasty but effectively detected existing acute post-angioplasty occlusions.

Angiography↗
PubMed1996

Polymerase chain reaction for non-invasive diagnosis of brain mass lesions caused by Mycobacterium tuberculosis: report of five cases in human immunodeficiency virus-positive subjects.

To investigate whether the polymerase chain reaction (PCR) on the IS6110 sequence of Mycobacterium tuberculosis could permit the early and non-invasive diagnosis of tuberculous brain lesions without meningeal involvement in acquired immunodeficiency virus patients, we examined retrospective cerebrospinal fluid (CSF) samples from five patients diagnosed as having cerebral lesions caused by M. tuberculosis. M. tuberculosis deoxyribonucleic acid was detected in CSF samples obtained from each of the patients studied, but in none of the controls. The PCR results coincided with M. tuberculosis isolation from CSF in two patients. In an additional two subjects, culture for M. tuberculosis on CSF was negative, and the diagnosis of central nervous system tuberculosis was achieved by response to specific therapy. In the last patient the PCR result on CSF was confirmed by isolation of M. tuberculosis from brain biopsy. Interestingly, in this patient the CSF did not yield M. tuberculosis isolation when cultured. The data show the value of PCR as a potentially useful approach for the early and rapid diagnosis of cerebral tuberculosis even without meningitis.

AIDS-Related Opportunistic Infections↗
PubMed1996

Transcervical chorionic villus sampling beyond 12 weeks of gestation.

The aim of this study was to evaluate the feasibility of transcervical chorionic villus sampling (CVS) after 12 completed weeks of pregnancy. The transcervical route for CVS, using thin biopsy forceps, was accomplished in 335 procedures in the study group, between 12 + 1 and 15 + 0 weeks. Cases were subdivided into two subgroups, the late (13 + 0 to 15 + 0 weeks) and intermediate (12 + 1 and 12 + 6 weeks) subgroups, and the results were compared with a previous series of 1202 early (8 + 0-12 + 0 weeks) transcervical CVS. A successful diagnosis was made in 97.3% of the cases. No differences were found in diagnostic success between the study subgroups, in comparison to the early transcervical CVS series. However, success rates in the study group increased from 90% in the first 60 procedures to 98.9% in the remaining cases (p < 0.001). Amniocentesis was eventually performed in nine cases (2.7%). All cases were rescanned 2 weeks after the procedure, and fetal demise was detected in five cases (1.5%). The spontaneous fetal loss rate up to 28 weeks was 3.1% (2.7% for intermediate and 4.0% for late subgroups). No cases of transverse limb reduction defects were observed. The results of our study suggest that the transcervical route for CVS beyond the 12th week of pregnancy has a satisfactory diagnostic success rate, and an acceptable pregnancy loss rate.

Adult↗
PubMed1996

Effects of hypoxia and hypercapnia on patterns of sleep-associated apnea in elephant seal pups.

This project examined the effects of alterations in respiratory drive on the occurrence of sleep apnea in Northern elephant seal pups (Mirounga angustirostris). Sleep pattern was unaffected by levels of hypoxia (approximately 13%) or hypercapnia (approximately 6%) that doubled respiratory frequency during slow-wave sleep (SWS). During sleep in air, short periods of continuous breathing (mean length = approximately 2.6 min) alternated with periods of apnea (mean length = approximately 6.1 min). Under hypoxic or hypercapnic conditions, the frequency of occurrence of apneas was reduced primarily due to the occurrence of some sleep episodes without periods of apnea. In episodes in which apneas did occur, they began later in the sleep episodes, but their length and the length of the periods of eupnea were not significantly altered. During each period of eupnea, however, the instantaneous respiratory rate and the total number of breaths increased. Breathing during sleep was restricted to SWS, never occurring during rapid eye movement (REM) sleep, regardless of the respired gas mixture. If the levels of hypoxia and hypercapnia were raised further, all episodes of apnea during sleep could be eliminated together with all episodes of REM sleep. One interpretation of the data is that the threshold for altering breathing during eupnea (instantaneous breathing frequency and number of breaths per episode of eupnea) is lower than that for altering the lengths of the periods of apnea and eupnea and that the muscle atonia associated with REM sleep extends to all respiratory muscles.

Animals↗
PubMed1995

Rapid fetal karyotype from cystic hygroma and pleural effusions.

Fluid from pleural effusion (n = 2) and cystic hygroma (n = 7) was obtained from eight fetuses, between 13 and 32 weeks of pregnancy at the time when a conventional prenatal diagnosis procedure was carried out. As these fluids contain lymphocytes, they were processed like peripheral blood. A karyotype was obtained in 4 days in both cases of pleural effusion and in four out of seven samples of cystic hygroma. An abnormal karyotype was detected in three of the four samples of cystic hygroma: two trisomies 21 and a monosomy X. Different parameters were evaluated in order to predict the feasibility of obtaining a cytogenetic diagnosis. Our data showed that if the amount of fluid obtained was > or = 4 ml and the initial lymphocyte count (ILC) was > 0.2 x 10(6) cells/ml, a cytogenetic diagnosis was possible from an initial concentration of cultured lymphocytes (ICCL) of > 0.06 x 10(6) cells/ml.

Body Fluids↗
PubMed1995

Chorionic villus sampling by biopsy forceps. Results of 1580 procedures from a single centre.

The results of a prospective series of 1580 chorionic villus sampling (CVS) procedures using biopsy forceps are presented. Most of the procedures (1442), including 11 sets of twins, were performed by the transcervical approach (TC-CVS), using a curved-shank thin forceps, and 138 by the transabdominal approach (TA-CVS), using a trocar-guided straight thin forceps. The mean gestational age for TC-CVS was 10.9 weeks, and in 233 cases (16 per cent) the procedure was carried out between the 12th and 14th weeks. The mean gestational age for TA-CVS was 16.7 weeks. The major indication for CVS was advanced maternal age (92.7 per cent in the TC and 91.8 per cent in the TA approach), and indications for abnormal ultrasound findings were more common in the TA approach (4.5 per cent) than in TC-CVS (0.07 per cent). Although sampling was apparently accomplished in all the procedures, in 3.1 per cent of the TC-CVS and 2.2 per cent of TA-CVS procedures, the samples were less than 1 mg after dissection. A cytogenic report was obtained in 96.1 per cent of the TC-CVS and 90.6 per cent of the TA-CVS. Maternal serum alpha-fetoprotein (MSAFP) was measured before and after TC-CVS and the post-CVS MSAFP was positively correlated with the sample weight. Second-trimester amniocentesis following CVS was required in 5.2 per cent (TC-CVS) and 6.5 per cent (TA-CVS), due to the failure to obtain a cytogenetic report or diagnostic confirmation. The follow-up to the 20th week was 100 per cent by ultrasound scan, and 88.6 per cent from the 21st week to 1 week after delivery. Fetal loss rates within 2 weeks of the procedure were 1.7 per cent (TC-CVS) and 0.8 per cent (TA-CVS) and total fetal loss accumulated to 1 week after delivery was 4.6 per cent (TC-CVS) and 5.9 per cent (TA-CVS). Factors found to increase significantly fetal loss in the TC-CVS series were maternal age and the collection of very small samples, but not the number of forceps insertions.

Adult↗
PubMed1995

Drug resistance of Mycobacterium tuberculosis strains isolated from HIV-infected Italian patients: preliminary report from a multicentric study. The Italian Tuberculosis Drug Resistance Study Group.

A multicentric prospective study started in March '93 to describe both initial and acquired resistance of Mycobacterium Tuberculosis in Italian HIV+ patients (pts.) to first line drugs: Rifampin (R), Isoniazid (I), Pyrazinamide (P), Ethambutol (E), Streptomycin (S). All tuberculosis (TB) cases diagnosed in HIV+ patients (pts.) were included, along with clinical-anamnestical data. Drug-susceptibility tests were performed centrally. Preliminary results indicate an overall low frequency of TB resistance to first line drugs: R = 2%, P = 4%, S = 9%, I/E = none. However, a relevant nosocomial outbreak of multiple drug resistant (DR) TB was detected. This finding, along with some previous Italian reports of DR-TB clusters, may herald a further spread of DR-TB. Surveillance, therefore, is mandatory in Italy from now on.

Antitubercular Agents↗
PubMed1994

Recognition of mental state terms. Clinical findings in children with autism and a functional neuroimaging study of normal adults.

BACKGROUND: The mind's ability to think about the mind has attracted substantial research interest in cognitive science in recent decades, as 'theory of mind'. No research has attempted to identify the brain basis of this ability, probably because it involves several separate processes. As a first step, we investigated one component process-the ability to recognise mental state terms. METHOD: In Experiment 1, we tested a group of children with autism (known to have theory of mind deficits) and a control group of children with mental handicap, for their ability to recognise mental state terms in a word list. This was to test if the mental state recognition task was related to traditional theory of mind tests. In Experiment 2, we investigated if in the normal brain, recognition of mental state terms might be localised. The procedure employed single photon emission computerised tomography (SPECT) in normal adult volunteers. We tested the prediction (based on available neurological and animal lesion studies) that there would be increased activation in the orbito-frontal cortex during this task, relative to a control condition, and relative to an adjacent frontal area (frontal-polar cortex). RESULTS: In Experiment 1, the group with autism performed significantly worse than the group without autism. In Experiment 2, there was increased cerebral blood flow during the mental state recognition task in the right orbito-frontal cortex relative to the left frontal-polar region. CONCLUSIONS: This simple mental state recognition task appears to relate to theory of mind, in that both are impaired in autism. The SPECT results implicate the orbito-frontal cortex as the basis of this ability.

Adolescent↗
PubMed1993

Multicentre evaluation of a biphasic culture system for recovery of mycobacteria from clinical specimens.

A new biphasic system (MB Check, Roche) for isolation of mycobacteria from clinical specimens was evaluated by eight different microbiological laboratories in comparison with methods routinely used in the respective laboratories. Altogether 1125 clinical specimens were processed; pretreatment, if performed, was by a variety of methods. Mycobacteria were recovered from 167 specimens with the biphasic system and 165 specimens with the other methods. The average time required for isolation of Mycobacterium tuberculosis was 22.6 days with the biphasic system and 24.7 days with egg-based media; for other mycobacterial species it was 23.5 versus 20.8 days. The inclusion of a chocolate agar section in the biphasic system facilitated the early detection of contaminants, while the NAP-containing section appeared unable to differentiate Mycobacterium tuberculosis from other mycobacterial species. The biphasic system, which enables recovery of mycobacteria in small laboratories without specialized equipment, is more practical than conventional methods and at least as sensitive.

Bacteriological Techniques↗