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Biomedical subjects

L Piazza

Publications and source records attributed to L Piazza.

At least 37 records · Page 2Linked to original sources
PubMed1990

Diagnosis and treatment of arachnoid cysts of the posterior fossa.

Arachnoid cysts of the posterior fossa are rare. When arachnoid cysts are encountered, the presenting symptoms are frequently otologic, with hearing loss and imbalance occurring commonly. Three cases are presented with a previously unreported otologic symptom, that of bilateral hearing loss, which in one case was fluctuant. None of the patients had the common symptoms of unilateral hearing loss and headache. With the advent of computed tomography and magnetic resonance imaging, these cysts may be readily identified, usually with diagnostic imaging alone. Unfortunately there is often a delay in diagnosis because of the vague and fleeting nature of the symptoms. Because no single diagnostic symptom pattern is able to characterize all cases, it is believed computed tomography or magnetic resonance imaging or both are indicated in patients with long-standing otologic complaints--even in the absence of unilateral symptoms. Treatment of posterior fossa arachnoid cysts primarily consists of surgical procedures designed to decompress the cyst. In this series, treatment with diuretics alone resulted in improvement of symptoms during several years of followup, with no evidence of enlargement of the cysts.

Adult↗
PubMed1989

Evaluation of pure tone and speech discrimination changes in Usher's syndrome.

Twenty-three adult patients with type 2 Usher's syndrome were evaluated for changes in pure tone average (PTA), discrete frequency thresholds, and speech discrimination scores. These patients were evaluated over a period of 5 years on the average (range, 2 to 9 years). Analyses of ear data showed a less than 10-dB change on PTA and discrete frequency thresholds for most ears. Of the ears that showed a threshold change greater than or equal to 10 dB, statistical significance was reached only at 4,000 Hz (p less than .01), where 11 ears representing ten patients dropped 10 to 15 dB. Speech discrimination data showed a greater than or equal to 16% change in score for 18 ears (12 patients). Sixteen of those ears (ten patients) had a 16% to 52% decrease in score (p less than .01), and the remaining two ears (two patients) showed a 20% and 30% improvement in score. These findings document little or no change in pure tone sensitivity for type 2 Usher's syndrome patients, but demonstrate the importance of monitoring their speech discrimination performance.

Adult↗
PubMed1987

Magnetic resonance imaging of central nervous system defects in Usher's syndrome.

With the use of magnetic resonance imaging, seven patients with type II Usher's syndrome were evaluated for CNS defects. The goals of this study were to confirm the presence of CNS defects previously detected by computed tomography (CT) scans in patients with Usher's syndrome while seeking additional anatomic defects in the posterior fossa employing a potentially more sensitive procedure using magnetic resonance imaging. Findings of CNS lesions in both the midbrain (high-signal-intensity lesions) and the cerebellum (vermian atrophy) necessitate further characterization of these defects in terms of their progressive nature and clinical significance for patients with Usher's syndrome.

Adult↗
PubMed1987

Expression of prokaryotic genes after transfection of X-irradiated plasmids into primate cells.

Expression of the prokaryotic gene for chloramphenicol acetyltransferase (EC 2.3.1.28) (CAT) in primate cells transfected with X-irradiated plasmid pSV2CAT was determined in transient expression assays. CAT expression did not depend upon the presence of supercoiled plasmids, but relaxed circular forms were essential. X-ray conversion of relaxed circles to linear forms paralleled the loss of CAT expression, with identical D0's in the first part of dose-response curves. X-ray-induced loss of supercoiled forms was complete at much lower doses. The D0 for inactivation of CAT expression by X irradiation of the plasmids in 1 mM Tris buffer was 270 Gy; it was 13 Gy for plasmids irradiated in water. The D0's for conversion of pSV2CAT to relaxed circle forms were only one-seventh as large as the D0's for CAT inactivation after X-ray in water or in 1 mM Tris buffer. Expression of the CAT gene in some representative repair-deficient human fibroblasts transfected with X-irradiated pSV2CAT was less than in monkey CV-1 cells or cell lines from normal human subjects. These results demonstrate a novel means to study low levels of X-ray damage in DNA correlating specific X-ray damage in the DNA with expression of the gene in unirradiated primate cells.

Acetyltransferases↗
PubMed1986

Visual acuity loss in patients with Usher's syndrome.

Using a life-table analysis, visual acuity loss with age was determined for a population of 106 patients with type 1 (N = 35) and type 2 (N = 71) Usher's syndrome. The cumulative percentage of patients maintaining visual acuity of 6/12 (20/40) or better in at least one eye by age 29 years was 69% for type 1 patients and 94% for type 2 patients. The cumulative percentage maintaining visual acuity of 6/24 (20/80) or better at this age was 89% for type 1 and 98% for type 2 patients. Within each subtype, the cumulative percentage maintaining 6/60 (20/200) or better was similar to the percentage maintaining 6/24 (20/80) or better. Knowledge of these data provides an objective basis for counseling patients with Usher's syndrome about their probability of developing loss of central visual acuity with age.

Actuarial Analysis↗
PubMed1984

Ascending aorta to femoral arteries by-pass: a safe surgical technique of lower limb revascularization in high risk patients undergoing coronary artery by-pass.

The coexistence of a coronary artery obstructive disease (CAOD) with aorto-iliac obstructive disease (AIOD) often represents a surgical problem. Because of left main coronary disease (LMCOD) the contemporary correction of AIOD should be performed with a simple non traumatic procedure. The case of a high risk patient in whom aortoiliac obstructive disease has been corrected with the implantation of a bifurcated vascular prosthesis from the ascending aorta to the bilateral common femoral arteries, and with a double aorto-coronary by-pass, is reported.

Aged↗
PubMed1980

[The preoperative evaluation of factors influencing low output syndrome in cardiac surgery (author's transl)].

For a preoperative evaluation of the factors influencing low output syndrome significatively in open heart surgery where statistically studied 15 factors upon a pattern of 400 patients operated with extracorporeal circulation: age, sex, weight; functional class; cyanosis; pulmonary hypertension; cardiopathy; arterial blood hypertension; myocardiopathy; left ventricular end-diastolic pressure; cardiac index; cardiothoracic index; aortic clamp duration; reoperation; extracorporeal circulation technique. Significant risk factors are: myocardiopathy; aortic clamp duration; functional class; pulmonary hypertension; reoperation; cardiac index; cardiothoracic index and arterial blood hypertension. These factors increase the studied pattern mean risk respectively of a 17.6%; 27.8%; 17.5%; 14.5%; 13.7%; 10.7%; 8.8% and 8.7%. Also myocardial protection technique was considered to be a significant risk factor, since mean risk for low output syndrome is much higher for these patients operated with the coronary perfusion, normothermy and simple hypothermy than for those operated with hypothermia and pharmacologic cardioplegia.

Adolescent↗
PubMed1980

[Propanidid as an antagonist: competitive inhibitor of neuromuscular plaque acetylcholinesterase].

Propanidid is a competitive inhibitor not only of serum cholinesterase, but of neuromuscular plaque and brain acetylcholinesterase also. The I50 of plaque acetylcholinesterase occurs at much higher concentrations of anaesthetic than for serum enzyme, this may depend on the environmental conditions under which propanidide has to act, or on acetylcholinesterase's high degree of specificity by comparison with pseudocholinesterase. Succinylcholine also inhibits serum cholinesterase but not plaque enzyme. With respect to the serum enzyme, the inhibition curve of the two drugs combined is similar to that of propanidide alone. The prolongation of apnoea observed during propanidide-induced anaesthesia, when succinylcholine is administered, does not appear to be due to diminution of serum cholinesterase activity but rather to interference of the two other drugs with neuromuscular transmission.

Animals↗
PubMed1979

[Down syndrome: immunological study in adults (author's transl)].

The immunological profile was evaluated in 12 adults affected by Down's syndrome. Our findings showed: increase of serum IgG, IgA and Gammaglobulins, decrease of IgM, presence of auto-antibodies and increased antibodies response after antigenic stimulation (typhoid vaccination). Some tests, connected with T lymphocytes functions, were also abnormal: percentage of E-active rosettes, cutaneous sensibilization with DNCB and lymphocyte stimulation index with PHA. Our findings suggest a T lymphocyte deficit, with loss of immunological surveillance and therefore of the control over antibody mediated immunological reactions. The immunological alterations observed in our adult patients with Down's syndrome were more extensive and severe than those found in young subjects. The possible relevance of these findings is discussed as well as the incidence of Alzheimer's dementia in adult patients with Down's syndrome.

Adult↗