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Biomedical subjects

A Passerini

Publications and source records attributed to A Passerini.

At least 19 recordsLinked to original sources
PubMed2000

Waste water from citrus processing as a source of hesperidin by concentration on styrene-divinylbenzene resin.

This paper describes a procedure for recovering hesperidin from the waste water of orange juice processing, namely, yellow water, by concentration of diluted extracts on styrene-divinylbenzene resin. Turbid raw material flowing out from centrifuges of essential oil separation contains considerable amount of hesperidin ( approximately 1 g/L) mainly associated with solid particles. Yellow water was treated with calcium hydroxide until pH 12 to solubilize hesperidin, filtered, neutralized at pH 6, and loaded on resin up to saturation. Desorption with 10% ethanol aqueous solutions at different NaOH concentrations (0.23-0.92 M) assured high concentration of hesperidin in selected fractions (10-78 g/L), from which it precipitated in high yield and purity immediately after acidification at pH 5. Best results were obtained using 0.46 M NaOH as eluent: 71.5% of the adsorbed hesperidin was desorbed in 300 mL, with an overall 64% yield of isolated product at 95.4% purity (HPLC). These experiments can constitute a useful starting point for an industrial application.

Citrus↗
PubMed1999

Recovery of hesperidin from orange peel by concentration of extracts on styrene-divinylbenzene resin.

This paper describes a new procedure for obtaining hesperidin from the waste orange peel of the citrus industry. It is based on the adsorption of dilute extracts of hesperidin on a styrene-divinylbenzene (SDVB) resin and the desorption in much more reduced volumes by means of alkaline eluents. Hesperidin immediately precipitates with good yield and high purity after acidification of the concentrated solutions, thus overcoming disadvantages due to the high dilution. Different experiments were carried out to examine operating conditions in each phase of the process. Hesperidin was extracted from peel with an aqueous saturated Ca(OH)(2) solution, allowing precipitation of calcium pectates from colloidal pectins that can interfere in the subsequent phases of adsorption and separation of hesperidin. The clear extracts were neutralized to optimize adsorption on resin. The most effective eluent was 0.5 N NaOH solution containing 10% ethanol. Recycling of the crystallization liquor improved the yield and purity of the product and reduced the acid amount required for neutralizing fresh alkaline extracts. Resin must be washed after each adsorption-desorption cycle and regenerated after five cycles. Results can constitute a useful starting point for an industrial application. A flow scheme of the process is also reported.

Adsorption↗
PubMed1991

Emotional profiles of families with a heart-operated patient: a pilot study.

Family interaction is a basic factor in determining the quality of life of patients undergoing heart surgery. The present study investigates the emotional attitudes in the relatives of 10 heart-operated patients. The results indicate that a high amount of relatives' emotional overinvolvement and warmth tends toward a correlation with lower anxiety and depression scores, and with a better 12-month outcome of the illness.

Anxiety↗
PubMed1990

Technical basis for magnetic resonance images.

The spin-echo procedure is the basic technique in a magnetic resonance (MR) study (the magnetization vector is flipped by 90 degrees onto the ortogonal plane to the main magnetic field). Very soon after the MR procedure was developed, it was pointed out how important it is to achieve the needed contrast with shorter repetition times (TRs) to reduce the imaging time. Recently, fast imaging techniques have been introduced (partial flip angles, short TRs, and the lack of 180 degrees radiofrequency pulses to refocus the spins are their main characteristics; the spins are refocused by the application of a gradient reversal technique). These techniques are particularly needed in pediatric neuroradiology, where the examination time must be as short as possible. At present, partial flip-angle techniques are almost completely replacing the conventional spin-echo procedure, but the variations in flip angle could result in a change in contrast. For these reasons, conventional spin-echo techniques may still be useful in a routine MR study.

Brain Diseases↗
PubMed1990

[Venous grafts in reimplantation of the thumb].

The Authors analyze their experience of 25 thumb reimplantations and revascularizations within 5 years. The importance of the first finger in the functional hand economy as well as the ratio between reimplantation take rate and degree of functional recovery with regard to the type of trauma, technique used, and possible and incidental complications are underlined. The venous autologous grafts are of great importance in this microsurgical area and they are more and more applied. In most cases, indeed, intimal lesions are more extended than their macroscopic appearance and the tract of damaged vessels is always wider than assessed. The graft interposition solves the problem with the further advantage to preserve the maximal bone length and to avoid especially contaminated areas. The results achieved confirm these statements and the Authors conclude for the absolute need of venous grafts in thumb reimplantations, especially after amputation from avulsion or crush traumas, even though a greater skill is necessary in using this technique.

Adolescent↗
PubMed1990

[Latissimus dorsi flap in reconstructive surgery of the lower limbs].

The free latissimus dorsi flap has been used to repair 10 complex losses of substance of the lower extremity. The results have shown the great reconstructive potentialities of the microvascular transfer of this muscle, considered by the authors the most versatile of the myocutaneous flaps. Among the advantages there are the extended surface, its thickness, its pedicle with adequate length and diameter as well as the absence of functional involvement, especially by preserving the upper branch of the thoracodorsal nerve. The indications, however, are limited due to a significant rate of complications which prevent its extended use.

Adolescent↗
PubMed1989

Computer-assisted planning of stereotactic neurosurgical procedures.

To extend the advantages of stereotactic localization to open procedures, a computational device with a graphic output is introduced. It is designed to be used in the operating room, where it processes neuroradiological information (CT, MR, and angiography) acquired under stereotactic conditions. The surgeon can interact with neuroanatomical data, extracting borders of structures of surgical relevance. The resulting sets of outlines, shown tridimensionally within the reference of a stereotactic head holder, are presented with respect to the planned approaching trajectory. Color-coded high-resolution graphics show the relationship between lesions and normal brain structures and guide the surgeon's access to deep-seated lesions through small exposures.

Humans↗
PubMed1989

[Magnetic resonance in brain tumors: a classification based on signal behavior in multiple echo sequences].

MR is generally known to be more sensitive but less specific than CT in the detection of brain lesions. In our opinion multiple echo sequences can markedly improve MR specificity in the diagnosis of tumors. We reviewed a series of 343 intracranial tumors studied with MR using multiple echo sequences and histologically verified. On the basis of the different signal patterns we divided brain tumors into 5 classes. Class 1: the signal intensity of the tumor increases progressively in T2 WI (100% of craniopharyngiomas, 21/21; 100% of epidermoid tumors, 12/12; 81% of astrocytomas (grades I to III), 64/79; 65% of neurinomas, 30/46). Class 2: the signal intensity of the lesion decreases progressively in T2 WI: A) the tumor has higher signal intensity than the parenchyma in all echoes (100% of medulloblastomas, 14/14; 53% of pituitary adenomas, 15/28); B) the tumor has the same signal intensity as the parenchyma in late echo acquisitions (100% of ependymal tumors, 12/12; 60% of meningiomas, 25/41). Class 3: the tumor has the same signal intensity as the parenchyma in all echoes (34% of meningiomas, 14/41). Class 4: glioblastoma model: one or more cysts of high signal intensity in T2 WI and slightly hyperintense nodules and/or rings and hyperintense peritumoral edema (73% of glioblastomas, 35/48; 72% of metastases, 18/25). Class 5: oligodendroglioma model: mixed hyper/hypointense pattern; cyst, calcifications and edema are very difficult to recognize within the lesion (95% of oligodendrogliomas, 18/19). The signal pattern was sometimes characteristic but never pathognomonic. Nevertheless, this classification proved to be an useful criterion to restrict the number of possible diagnoses. The study of T1 and T2 values seems to be less useful.

Brain↗
PubMed1986

Mobile myelographic filling defects: spinal cysticercosis.

Cysticercosis usually affects the brain and is easily demonstrated by CT. Spinal cysticercosis is much rarer and is usually diagnosed only at surgery. Myelographic demonstration of multiple rounded filling defects, some of which were mobile, allowed diagnosis of spinal extramedullary cysticercosis in an unsuspected case. The literature on spinal cysticercosis is briefly reviewed. Diagnosis is important in view of the recent development of medical treatment.

Arachnoiditis↗
PubMed1986

Magnetic resonance imaging in intracranial gliomas. Comparison with computed tomography and serial stereotactic biopsy.

Findings at magnetic resonance imaging (MRI) and computed tomography (CT) where reviewed in 53 surgically confirmed cases with glioma. Astrocytomas showed a constant MR signal pattern in 87 per cent and glioblastomas in 80 per cent. This pattern was found useful when it was correlated with CT. MRI was also found to be of value in planning stereotactic biopsy and in confirming the trajectory.

Biopsy↗
PubMed1986

[Magnetic resonance in the study of cerebral gliomas].

Forty surgically proved gliomas have been studied by MR: 21 were low-grade gliomas and 19 were anaplastic astrocytomas and glioblastomas. The examination involved the use of T1-weighted (IR and/or SE, TR 500 ms, TE 50 ms) and T2-weighted scans (SE, TR 1000 ms, TE 50 with multiple echos). All patients underwent CT and surgical removal or stereotactic biopsy whose findings were retrospectively compared with those of MR. MR findings were similar in low-grade and anaplastic astrocytomas, but quite different from imaging of glioblastomas. Tumoral cyst and areas of necrosis were recognized on MR studies and confirmed by surgical findings. Differentiation between tumor and oedema was difficult. The MR images did not allow a more specific diagnosis of nature or of malignancy than available with CT up to now, but offer major advantages, such as a superior depiction of tumor extent and anatomic relationships.

Adolescent↗
PubMed1985

Intracranial tumors arising from the floor of the middle fossa.

Tumors involving or arising from the floor of the middle fossa in cases seen at the Neurological Institute C. Besta were reviewed, and the radiological findings of plain films, angiographic and CT studies are described. Meningiomas, metastases, trigeminal neurinomas, epidermoids, chordomas and chondromas were included in the study.

Brain Neoplasms↗
PubMed1982

Chronic subdural hematoma: reliability of radioisotope imaging versus computed tomography.

25 surgically verified cases of chronic subdural hematoma (CSH) were examined retrospectively. All the patients had been investigated both with computed tomography (CT) and with radioisotope imaging (RI). RI supplied a correct diagnosis in all cases whilst CT yielded a doubtful diagnosis (generic signs of space-occupying lesion) in 5 cases and normal findings (false negative) in one. The clinical use of the two investigations is discussed. The study shows the reliability of RI in the diagnosis of CSH especially when CT determines the site but not the nature of the lesion (hematoma in the isodense phase).

Chronic Disease↗
PubMed1980

Segmental action and stimuli-sensitive myoclonus with acute onset. A case report.

A 23-year old man developed action and stimulus-sensitive myoclonus involving neck and proximal arm muscles. The finding of abnormally long and tortuous vertebral and carotid arteries and the abrupt onset of symptomatology suggest a possible hemodynamic mechanism. The electrophysiological characters and the sensitivity to serotonin precursors are consistent with the definition of "reticular reflex myoclonus".

5-Hydroxytryptophan↗
PubMed1978

CT, angiography, and RN scans in intracranial cavernous hemangiomas.

Nine cases of surgically verified intracranial cavernous hemangiomas are reported. A comparison is made between radionuclide brain scans, angiography, and CT studies: RN scans are sometimes superior to angiography in indicating the presence of the lesion; CT is the most informative investigation, although it does not present a specific pattern. A preoperative specific diagnosis can only be suggested on the basis of the whole complex of the information available, including the clinical history.

Adolescent↗