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Biomedical subjects

A Oliva

Publications and source records attributed to A Oliva.

At least 127 records · Page 7Linked to original sources
PubMed1991

Effects of handedness and sex on the morphology of the corpus callosum: a study with brain magnetic resonance imaging.

In view of conflicting data in the existing literature, we examined 53 normal subjects using a handedness questionnaire and callosal area measurements obtained from midsagittal MRI images. The callosum was found to be significantly larger in nonconsistent right-handers (NCRH), especially in its anterior half and especially for males. A significant hand x sex interaction, favoring consistent right-handed (CRH) females, was also found for the posterior midbody, a region known to house interhemispheric fibers connecting the right and left posterior association cortices. These results (1) confirm Witelson's (1985) first findings on postmortem specimens; (2) validate a dichotomy between CRH and NCRH rather than simply considering the writing hand, as was the case in most other similar studies; and (3) suggest that at least two different sex-related--probably hormonal--factors may be acting during the callosal development, one explaining the larger anterior half in NCRH males and the other the larger posterior midbody in CRH females.

Adolescent↗
PubMed1991

Histamine hyperresponsiveness of the extrathoracic airway in patients with asthmatic symptoms.

Functional abnormalities of the extrathoracic airway (EA) may produce symptoms mimicking bronchial asthma. We assessed the bronchial (B) and EA responsiveness to inhaled histamine in 40 patients with asthmatic symptoms and in nine asymptomatic controls. FEV1 and maximal mid-inspiratory flow (MIF50) were used as index of bronchial and EA narrowing. Hyperresponsiveness of the intra-(BHR) or extra-(EA-HR) thoracic airway was diagnosed when the provocative concentrations of histamine (PC20FEV1 or PC25MIF50) were less than 8 mg/ml. Fiberoptic laryngoscopy was performed in nine patients and three controls. The glottal region was measured at mid-volume of maximal inspiration (AgMI) and expiration (AgME) before and after histamine. Predominant EA-HR was found in 13 patients, predominant BHR in 12, equivalent BHR and EA-HR in another 12; no significant airway narrowing was observed in three patients and in the nine controls. EA-HR was significantly associated with female sex, sinusitis, post-nasal drip, dysphonia; BHR with atopy, wheezing and lower MEF50. The percent change in AgMI after histamine was closely related to the PC25MIF50 (r = 0.87, P less than 0.001), that of AgME to the PC20FEV1 (r = 0.78, P less than 0.01). These findings suggest that the assessment of EA responsiveness may be useful in the evaluation of asthmatic symptoms, especially in patients with no BHR.

Asthma↗
PubMed1991

Lower extremity replantation.

Replantation of the traumatically amputated lower extremity is a technically feasible surgical undertaking. Successful outcome must be judged by functional achievements of the patient toward returning to the preinjury level. Appropriate patient selection significantly increases the potential for obtaining a satisfactory outcome. Patients in whom peripheral nerve injury precludes return of sensation in the extremity or in whom severe joint destruction will yield an immobile extremity will have marginal results. The risks of replantation, including blood transfusions, sepsis, and prolonged hospitalization, must be weighted heavily against prosthetic substitution as an alternative. If the lower extremity can be successfully replanted, however, this provides a superior functional and aesthetic result for the patient. Salvage replantation to preserve maximal functional length and durability of an extremity must always be considered when assessing a patient with a traumatic amputation. Free-tissue transfer to salvage a threatened replanted limb must be similarly a part of the armamentarium of the replantation surgeon. Although lower limb replantation may continue to be controversial, improved surgical techniques and increasing experience make it an excellent alternative to prosthetic substitution. In the well-motivated patient, an excellent result may be achieved.

Adult↗
PubMed1991

Microsurgery: directions for the 1990s.

Speculating on the possible advances of microsurgery in the 1990s has encompassed discussion of transplantation technique, biochemistry, monitoring, and nerve and motor reconstruction. This article, however, is by no means exhaustive, and many other discoveries and innovations may come from areas not discussed here. The only clearly incorrect possibility concerning microsurgery in the 1990s is that nothing exciting will happen.

Fingers↗
PubMed1990

The use of crossed polarized filters in the measurement of the relative afferent pupillary defect.

We used crossed polarized neutral density filters to quantitate relative afferent pupillary defects. To prove reproducibility, the relative afferent pupillary defects of 20 patients were measured with this technique by two independent observers. There was no statistically significant difference between the two measurements. Relative afferent pupillary defects as low as 0.03 log unit were easily measured. These filters offer a convenient and reproducible technique that is more sensitive than the use of neutral density filters.

Evaluation Studies as Topic↗
PubMed1990

Physicochemical and immunological studies on mammalian 5'-deoxy-5'-methylthioadenosine phosphorylase.

5'-Deoxy-5'-methylthioadenosine phosphorylase (MTAase) was purified to homogeneity (10,000-fold) from bovine liver with a recovery of 12%. The pure protein shows a molecular weight of about 98,000 +/- 3,000 and is composed of three apparently identical subunits. Several physicochemical features have been investigated including hydrodynamic properties, amino acid composition, and secondary structure. In particular, the CD spectrum of the protein indicates a very low alpha-helical content and a large percent of beta-structure and random coil. The pure protein was used to raise specific rabbit antisera but, because of the scarce antigenic properties of the native enzyme, different chemically modified forms were prepared and employed as immunogens. Among the antibodies obtained, those to keyhole limpet hemocyanin-MTAase recognize both the native and the denatured enzyme and are also active against the human protein. Therefore, they were employed as a tool to investigate the occurrence of inactive forms of MTAase in two human malignant cell lines lacking this enzymatic activity. The results obtained with K562 and Jurkat cells indicate that the protein is absent in these phosphorylase-deficient cell lines.

Amino Acids↗
PubMed1990

The nodular form of local hepatic tuberculosis. A review.

Local hepatic tuberculosis without active pulmonary or miliary tuberculosis is an uncommon diagnosis. Even less common is the finding of tuberculoma or tuberculous liver abscess without clinical evidence of tuberculosis elsewhere. Since 1950, 21 cases of isolated tuberculoma or tuberculous abscess of the liver have been reported in the world literature. We report an additional two cases, one tuberculoma and one with multiple tuberculous abscesses. The case reports illustrate the difficulty in reaching the correct diagnosis, unsuspected in nearly all cases and most often confused with carcinoma of the liver. The correct diagnosis was made by histology, identification of acid-fast organisms by smear, and by cultures of Mycobacterium tuberculosis, but required laparotomy in 19 of the 23 cases. A greater awareness of this rare clinical entity may prevent needless surgical intervention since the vast majority of patients respond well to antituberculous chemotherapy.

Adolescent↗
PubMed1990

Convergence-evoked nystagmus.

We describe 17 patients with acquired convergence-evoked nystagmus (CEN). Vertical CEN was most common (82%), with upbeat much more frequent than downbeat. The most common diagnoses were multiple sclerosis (41%) and brainstem infarction (29%). CEN is an easily elicited bedside sign of posterior fossa dysfunction and can be a clinically useful manifestation. In cases of isolated optic neuritis, the presence of CEN may indicate dissemination of neurologic disease.

Adult↗
PubMed1990

Hyperresponsiveness of the extrathoracic airway in patients with captopril-induced cough.

It has been suggested that cough from captopril may originate from an increased sensitivity of receptors in the extrathoracic airway (EA). To explore this hypothesis, we assessed the responsiveness of EA and bronchi and the cough sensitivity to inhaled histamine in nine hypertensive patients with captopril-induced cough (group 1) during treatment and one month after withdrawal of the drug treatment. Nine patients who were asymptomatic while receiving captopril (group 2) and nine patients receiving no current treatment (group 3) served as controls. The EA responsiveness was assessed by using the maximal midinspiratory flow (MIF50) as an arbitrary index of EA constriction and was expressed as the histamine concentration causing a 25 percent decrease in MIF50 (PC25MIF50). PC15FEV1 was the index of bronchial responsiveness and PCcough (dose causing five or more coughs) was that of cough sensitivity. Airway hyperresponsiveness (EA-HR or BHR) was diagnosed when PC25MIF50 or PC15FEV1 were 8 mg/ml or lower. Patients with captopril-cough, as compared with controls, had significantly lower values of PC25MIF50, PC15FEV1, and PCcough; EA-HR and BHR were found, respectively, in seven and three of these patients and in none of the control subjects. In all the patients of group 1, cough and EA-HR resolved after withdrawal of captopril treatment, while BHR persisted in one. PC25MIF50, PC15FEV1, and PCcough were all significantly improved. Our findings suggest that cough during captopril therapy may originate from receptors in the EA.

Bronchial Provocation Tests↗
PubMed1990

Hypomagnesemia in chronic obstructive lung disease: effect of therapy.

In 95 patients with severe chronic airway obstruction (FEV1 33.2 +/- 12% of predicted; mean +/- SE), we investigated whether drug therapy had any influence on serum Mg levels. 11/95 patients had a serum Mg less than 1.45 mEq/l (lower normal limit). Multiple-regression analysis showed that the use of diuretics was associated with a significantly lower serum Mg level (1.59 +/- CI 0.06 mEq/l vs. an adjusted mean of 1.71 mEq/l; F = 11, 2, p less than 0.001). There was a significant negative correlation between serum Mg and the length of oral steroid therapy (1.64 +/- CI 0.02 mEq/l for less than 24 months of therapy vs. 1.52 +/- CI 0.06 mEq/l for greater than 24 months of therapy; F = 7, 3, p less than 0.005). No effect of theophylline, inhaled steroids or beta 2-agonists on serum Mg was observed. Because of potential negative effects of hypomagnesemia on respiratory function, routine serum magnesium determination is recommended in patients with chronic obstructive lung disease taking diuretic drugs or corticosteroids.

Administration, Inhalation↗
PubMed1990

An Entamoeba histolytica antigen devoid of enzymatic activity, but endowed with immunogenic and protective properties.

One of the most relevant features of Entamoeba histolytica extracts is their great enzymatic activity. The consequence of this peculiarity is that these extracts digest not only extrinsic proteins but also those within the parasite, causing instability during extract preparation which makes their characterization more difficult and hinders their use in immunoprophylaxis. This report presents evidence which indicates that treatment of E. histolytica extracts with a pH2 acid shock for 30 min at 37 degrees C irreversibly, as shown through its reactivity with polyclonal E. histolytica antisera and through its capacity to induce antibody formation and to protect against intrahepatic challenge with E. histolytica. Among the foremost activities in the field of immunoparasitology are the identification, isolation, purification and characterization of parasite antigens, particularly because of their potential use in immunoprophylaxis. Given the world wide distribution of amebiasis, particularly in undeveloped countries, various researchers have given special importance to the antigenic characterization of the causal agent, Entamoeba histolytica, and to its ability to induce protective immunity in several animal models. Initial studies demonstrated that the parasite produces a variety of proteolytic enzymes which play an important role in the immune response and pathogenesis of the infected host. Additionally, these enzymes cause autodegradation of the amebic extracts, their use in immunoprophylaxis, since proteins germane in inducing protection could be degraded. Even though enzymatic activity may be abolished through specific inhibitors, these are very toxic and therefore not adequate for biological material to be tried on humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Auditory evoked potentials of the brain stem in brain injury. Prognostic value].

The study of brain stem auditory way in severe head trauma patients with auditory evoked potentials is very important for giving elements about functional and anatomic situation of analyzed neuronal substratum; ABR will be normal or altered in conformity with the level and/or the gravity of the damage. Authors have examined 20 post-traumatic comatose patients pointing out the existence of a strict relation between auditory brain stem responses and prognosis. Authors, in accordance with the ample literature in existence, agree to point out the auditory brain stem responses such as a very effective instrument for the prognostic valuation of post-traumatic comatose patients.

Adolescent↗