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Biomedical subjects

M Rizzo

Publications and source records attributed to M Rizzo.

At least 19 recordsLinked to original sources
PubMed1992

Unusual relapse of hepatocellular carcinoma.

The authors report a patient with iatrogenic dissemination of hepatocellular carcinoma (HCC). A 65-year-old Caucasian man was found to have a moderately well-differentiated HCC diagnosed by laparoscopy and biopsy; the patient had atypical left liver lobe resection. Thirty-three months after definitive surgery a double relapse was found at the site of the previous laparoscopy and at the surgical scar; no other metastases were found. Surgical procedure for removal of these lesions was performed, and the patient received complementary radiation therapy. At 30 months of follow-up, the patient is alive and disease free. The risk of neoplastic seeding through biopsy and improved safety in surgical techniques justify the omission of diagnostic biopsy in patients who have surgical procedures.

Aged↗
PubMed1992

Troubled reaching after right occipito-temporal damage.

We encountered a man with an unusual reaching disturbance due to a stroke in the right occipito-temporal cortex and subjacent white matter. We studied his behavior in detail including vision and hand control. He had a left homonymous hemianopia. In his remaining fields static visual acuity and stereoacuity were normal, but he could not detect a coherent motion signal or follow moving targets with smooth pursuit. Transduction of limb movements using an optoelectronic technique showed abnormal morphology, increased variability and markedly prolonged latencies for transport to external visual targets, yet he achieved these targets with precision. Reaching to self-bound targets, and to the remembered locations of external targets with vision blocked was 5 x faster. The findings may be explained by: (1) damage in regions homologous to areas TF and TH in the monkey, which provide visual inputs to hand and forelimb representations in the cortex; (2) injury in human regions homologous to the monkey's MT complex, with inability to use visual information on the movement of the limb due to a visual motion processing defect; and (3) disruption of visual cortical-subcortical connections mediating crucial transformations among limb and target representations.

Ataxia↗
PubMed1992

Orienting attention in audition and between audition and vision: young and elderly subjects.

This study examined 30 young and 10 elderly subjects to test whether orienting of attention could be measured in audition. Orienting in a mixed-modal condition in which stimuli were either auditory or visual was also tested. The dependent measure was the reaction time (RT) to lateralized targets when the locations were predicted by antecedent arrow cues that were correct (valid), were incorrect (invalid), or provided no lateralizing information (neutral). A comparison between the two groups among the different conditions showed that elderly subjects had longer RTs than the younger participants, but the pattern of results was similar in both groups. In addition, a similar RT pattern was found for each modal condition: Valid trials elicited the fastest responses and invalid trials the slowest. These findings suggest that the mechanisms involved in orienting attention operate in audition and that individuals may allocate their processing resources among multiple sensory pools. Moreover, effects seen in orienting attention in audition were similar to those found in vision and are interpretable with the same types of models. Orienting attention appears to be relatively resistant to the aging process in the sample of subjects tested in this study.

Acoustic Stimulation↗
PubMed1992

Ureterocalicostomy in the treatment of pyeloplasty failures.

Ureterocalicostomy was performed in 8 patients following failed pyeloplasty: 2 had undergone two previous pyeloplasties, while endourological management had been attempted in 3. With a mean follow-up of 58.7 months, radiographic studies demonstrated resolution of the obstruction in 6 cases (75%), while two kidneys lost their function. The definitive role of endourological techniques after pyeloplasty failure still waits the test of time although they deserve to be applied first, and ureterocalicostomy remains a reliable procedure in this particular setting.

Adult↗
PubMed1992

A human visual disorder resembling area V4 dysfunction in the monkey.

We surveyed a broad range of visual functions in a man who complained of abnormal color experience and inability to recognize faces following bilateral damage in the visual cortex. A lesion in his right visual cortex caused complete left visual field loss. A lesion in his left visual cortex, located entirely below the calcarine fissure, affected the vision in his remaining hemifield, the right one. Psychophysical testing showed severely defective color vision and pattern processing, but relatively normal luminance contrast detection thresholds. The finding of normal spatial contrast sensitivity and static stereopsis did not resemble a parvocellular defect of the type described in the monkey. The abilities to detect global coherent motion among noise, structure from motion and dynamic stereopsis, and to pursue moving targets showed normal motion processing at several levels. Together with normal flicker perception, these results excluded magnocellular or MT-like defects. Altogether, the findings mimic area V4 dysfunction.

Adult↗
PubMed1992

Xanthogranulomatous pyelonephritis in pelvic ectopic kidney.

Xanthogranulomatous pyelonephritis occurred in a pelvic ectopic kidney in a 70-year-old man. Pre-operative diagnosis was possible due to the typical appearance at CT scan of central lithiasis and multiple rounded areas of low density with enhancing rims (bear paw sign).

Aged↗
PubMed1991

Correlation between aminoglycoside resistance profiles and DNA hybridization of clinical isolates.

DNA hybridization data and aminoglycoside resistance profiles (AGRPs) were determined for 4,088 clinical isolates from three studies (United States, Belgium, and Argentina). The correlation between susceptibility profiles and hybridization results was determined with nine DNA probes. For each of the seven aminoglycoside resistance profiles which we were able to test, the data suggested at least two distinct genes could encode enzymes which lead to identical resistance profiles. Furthermore, the DNA hybridization data showed that individual strains carried up to six unique aminoglycoside resistance genes. DNA hybridization revealed interesting differences in the frequencies of these genes by organism and by country.

Acinetobacter↗
PubMed1991

Early screening and treatment of "silent" patent ductus arteriosus in prematures with RDS.

From January 1987 to December 1989, prematures with RDS weighing 1750 g or less admitted to the Neonatal Intensive Care Unite (NICU) were submitted from the third postnatal day to serial two-dimensional and pulsed Doppler (ATL MK 600) echocardiographic evaluation for "silent" patent ductus arteriosus (PDA). PDA was diagnosed in 36/175 prematures with RDS (20.5%). Thirty patients had indomethacin treatment and the PDA closed completely in 27 (90%); five needed a second course of indomethacin, that was effective in two (40%). Four RDS patients (4/36-11%) already weaned from the respirator, needed supplemental oxygen. The three non-responders and six other prematures with counterindications to the drug underwent surgical ligation (25%). As historical control, we retrospectively evaluated the population of preterm infants with RDS weighing less than or equal to 1750 g treated for hemodynamically significant PDA during three previous years before the screening protocol; in this group the echocardiographic and Doppler evaluations were done when congestive heart failure and pulmonary edema were clinically evident. In comparison, we found a reduced incidence of prematures with RDS treated for PDA, 7/120 (5.8%) a higher age at medical treatment (9 +/- 1.4 vs 4.4 - 2.3 days) and a larger prevalence of patients underwent ductal ligation (71.4%). These data show that early screening and treatment of "silent" PDA may result advantageous to improve the efficacy (90%) of indomethacin, in a critical time for the recovery of RDS, and furthermore decreasing the need of surgical ligation.

Birth Weight↗
PubMed1990

Human pharmacokinetic and pharmacodynamic profiles of leuprorelin acetate depot in prostatic cancer patients.

A total of 21 patients with advanced prostatic cancer and one patient with benign prostatic hypertrophy received 3.75, 7.5 or 15 mg leuprorelin acetate depot subcutaneously. Serum leuprorelin concentrations increased immediately after injection, reaching a peak concentration (range 13.1-54.5 ng/ml), which was directly proportional to dose, within 3 h. Mean drug levels subsequently declined to a plateau directly proportional to dose at 5 weeks. There was also a significant (P less than 0.01) dose-dependent increase in the area under the concentration-time curve for 0-35 days. Serum concentrations of luteinizing hormone and follicle stimulating hormone rose initially with all doses, followed by a rise in serum testosterone and dihydrotestosterone concentrations, which then fell sharply, within 3 weeks. A reduced level of follicle stimulating hormone subsequently occurred in all 20 evaluable patients and was maintained in 17 patients over 5 weeks. There was also marked initial suppression of luteinizing hormone levels in 15 patients and in 13 this continued. Castration levels of testosterone and dihydrotestosterone were maintained in all patients for up to 5 weeks. In two patients there was a complete response, in 14 a partial response and in three stable disease, with no significant differences in relation to dose. Clinical improvement and serum hormonal changes suggest that leuprorelin acetate depot is effective at a dose as low as 3.75 mg when given once every 4 weeks.

Aged↗
PubMed1990

Leuprorelin acetate depot in advanced prostatic cancer: a phase II multicentre trial.

The therapeutic efficacy and safety of various doses of leuprorelin acetate depot were determined in an open, multicentre study of patients with locally advanced or metastatic prostatic cancer (stages C, D1 or D2). Patients were randomly assigned to receive 3.75 mg (30 cases), 7.5 mg (eight cases), 15 mg (eight cases) and 30 mg (one patient) leuprorelin acetate depot administered subcutaneously once every 4 weeks. Of the 43 patients evaluable, two (5%) had complete remission, 23 (53%) partial remission and 13 (30%) patients stable disease. No significant differences were observed in response rates in relation to dose, disease stage or previous hormonal therapy. Disappearance or improvement in bone pain and urinary symptoms occurred in 63% and 79% of cases, respectively. Serum androgen concentrations decreased rapidly and persistently to castration levels, without significant differences for different doses. Treatment was well tolerated with a low incidence of mild side-effects - gynaecomastia (16%), nausea/vomiting (13%) and diarrhoea (2%). It is concluded that 3.75 mg leuprorelin acetate depot given subcutaneously once every 4 weeks is able to produce hormonal effects in all patients, an overall objective response comparable to that obtained using higher doses.

Aged↗
PubMed1990

Simultanagnosia: a defect of sustained attention yields insights on visual information processing.

Simultanagnosia, in which subjects report a piecemeal visual experience, offers an important probe of human attention. We studied 2 subjects with simultanagnosia following bilateral superior occipital strokes. Compared with controls, they could orient attention to spatial targets in visual, auditory, and mixed-modal conditions. A different task required immediate response to the appearance or disappearance at unpredictable intervals of any element in a random-dot CRT display. The subject tested could detect less than 50% of 1,600 events, and had increased "mirages" and prolonged reaction times. Undetected events occurred anywhere and formed temporal clusters. Application of signal-detection theory confirmed abnormal sensitivity and response bias (d' and beta). Yet performance improved when a valid cue introduced events in the random display. Our results suggest that simultanagnosia was related to an inability to sustain visuospatial attention across an array, corresponding to processing failure at a level of long-range (global) spatiotemporal interactions among converging inputs from early vision. The operations for orienting and sustaining attention may be dissociable at visual association cortex levels.

Adult↗
PubMed1990

Antihypertensive effects of CGS 19281A, an inhibitor of phenylethanolamine-N-methyltransferase.

In experimental hypertension, phenylethanolamine-N-methyltransferase (PNMT) activity and adrenaline levels are elevated in brainstem centers involved in cardiovascular regulation. Known PNMT inhibitors used to lower blood pressure have invariably shown alpha adrenergic activity as a side effect. A search for new inhibitors disclosed that CGS 19281A (4,9-dihydro-7-methoxy-3H-pyrido[3,4b]indole) inhibits PNMT (IC50, 2.7 x 10(-6) M) without interacting with the alpha-1 or alpha-2 adrenergic receptors. CGS 19281A (20 mg/kg i.v.) reduced PNMT activity (60% decrease; P less than 0.001) and adrenaline concentration (38%; P less than .025) in the brainstem of normal rats. In conscious deoxycorticosterone acetate-salt rats and spontaneously hypertensive rats, CGS 19281A (20 mg/kg i.v.) decreased blood pressure (50 mm Hg; P less than .001) and heart rate (26-36%; P less than .001) for 3 hr. Elevated brainstem adrenaline levels in deoxycorticosterone acetate-salt rats were decreased by CGS 19281A (42%; P less than .005) whereas i.c.v. administration of CGS 19281A (845 nmol/rat) to conscious spontaneously hypertensive rats decreased blood pressure (20 mm Hg; P less than .010) and heart rate (84 beats/min; P less than .001) as well. Therefore, CGS 19281A may be useful for the study of the function of PNMT and adrenaline in the central nervous system.

Animals↗
PubMed1989

Isolation, characterization, and DNA sequence analysis of an AAC(6')-II gene from Pseudomonas aeruginosa.

The gene encoding a 6'-N-acetyltransferase, AAC(6')-II, was cloned from Pseudomonas aeruginosa plasmid pSCH884. This gene mediates resistance to gentamicin, tobramycin, and netilmicin but not amikacin or isepamicin. The DNA sequence of the gene and flanking regions was determined. The 5'- and 3'-flanking sequences showed near identity to sequences found abutting a variety of different genes encoding resistance determinants. It is likely that the current structure arose by the integration of the 572-base-pair sequence containing the AAC(6')-II gene into a Tn21-related sequence at the recombinational hot spot, AAAGTT. We have compared the sequence of the AAC(6')-II gene to genes of other 6'-N-acetyltransferases. An AAC(6')-Ib protein (encoded by the aacA4 gene; G. Tran Van Nhieu and E. Collatz, J. Bacteriol. 169:5708-5714, 1987) that results in resistance to amikacin but not gentamicin was found to share 82% sequence similarity with the AAC(6')-II protein. We speculate that these two genes arose from a common ancestor and that the processes of selection and dissemination have led to the observed differences in the spectrum of aminoglycoside resistance.

Acetyltransferases↗
PubMed1989

Interferon alpha-2a and vinblastine in the treatment of metastatic renal carcinoma.

Twenty patients with measurable metastatic renal cell carcinoma (RCC) were treated with interferon alpha-2a (18 X 10(6) IU i.m. 3 times weekly) in combination with vinblastine sulfate (0.1 mg/kg i.v. every 3 weeks). Objective responses in the lungs, bone and liver metastases were observed in 5 of 18 evaluable patients. Dose reduction of interferon alpha-2a (to 9 X 10(6) IU i.m. 3 times weekly) was necessary in 7 patients due to intolerable flu-like side effects and leukopenia (nadir 3,500 leukocytes/mm3). Tolerance was good in 55% of cases. Objective clinical response was observed in 27.7% of patients, and only 38.8% progressed. It is necessary to perform further studies, varying the therapeutic schedules, in order to elicit a better control of the toxic effects and a greater objectiveness of the clinical response.

Adenocarcinoma↗
PubMed1989

The effect of bilateral visual cortex lesions on the development of eye movements and perception.

We studied the eye movements and visual perception in a man with extensive bilateral occipital lesions acquired at birth. He had 3/500 acuity, limited visual fields, and extrafoveal fixation attributable to an intact left superior visual cortex. Analysis of digitized electro-oculography and magnetic search coil data showed normal saccade dynamics. He could make voluntary saccades. Smooth pursuit of suprathreshold targets was mostly saccadic and did not improve with added nonvisual cues. Our results support the hypothesis that the visual cortex is crucial to the development of eye movements. The foveal representation in the occipital lobes, missing in this subject, is needed for development of normal smooth pursuit.

Adolescent↗
PubMed1989

Colored hearing synesthesia: an investigation of neural factors.

We studied a 17-year-old boy with colored hearing synesthesia (chromesthesia) using psychophysical and neurophysiologic tests. Specific musical notes consistently evoked the same color hues. Unlike controls, he could make new musical note-color associations in a single trial. Auditory evoked potential studies showed no evidence of abnormal activation. The results in this subject do not favor the notion that chromesthesia was due to aberrant neural transmission in collateral pathways, and support the alternative hypothesis that chromesthesia results from strong cross-modal associative ability.

Adolescent↗