Search PubMed⌕ Search

Biomedical subjects

M Rizzo

Publications and source records attributed to M Rizzo.

At least 145 records · Page 8Linked to original sources
PubMed1996

Adaptive morphological changes of the intestinal mucosa in orthotopic ileal bladder. Short-term and long-term evaluation.

The morphology of the mucosa of orthotopic ileal bladders in place for 3 months to 4 years was studied in biopsies obtained at random from 12 patients. A mucosal flattening, a reorganization of the lining epithelium and a disappearance of the fenestrated areas of blood capillaries were found. Enterocytes progressively stratified and acquired poorly differentiated features, along with loss of microvilli, reduction of the apical fuzzy glycocalyx and enlargement of intercellular spaces. Goblet cells at short-term evaluation were actively involved in mucous synthesis and secretion. Metabolic acidosis was slight both in short-term postoperative periods-under alkaline therapy- and in long-term postoperative periods-when therapy was suspended. It can be concluded that, firstly, urine contact determines in such reservoirs a condition of acute irritation and, secondly, environmental changes induce the ileal mucosa to develop a new phenotype probably better suited to a protective rather than absorptive function.

Aged↗
PubMed1995

The subacute levodopa test for evaluating long-duration response in Parkinson's disease.

The clinical relevance of a long-duration response (LDR) to levodopa therapy in Parkinson's disease (PD) has not been widely recognized. In 25 patients with moderate PD, we measured LDR on motor function after short periods of treatment with levodopa (subacute tests). Each subacute test lasted 15 days and consisted of the oral administration of levodopa at various interdose intervals (IDIs) of 48, 24, 12, 8, 6, and 5 hours. The goal for a subacute test was to achieve a satisfactory antiparkinsonian effect before the last levodopa dose (day 15), i.e., an LDR greater than 50% of the maximal response following an acute levodopa test (LDR-endpoint). Twenty-one patients (84%) reached the LDR-endpoint. The IDI at which levodopa was administered clearly differentiated patients who were otherwise clinically indistinguishable when evaluated at baseline off medication or after an acute levodopa test. The IDI schedule that produced a satisfactory LDR was specific for each patient, since longer DIs failed to produce the required LDR, and a shorter IDI schedule (resulting in larger cumulative dosage of levodopa) did not significantly enhance the response. Also, the LDR decay rate after discontinuation of treatment was individual for each patient and independent of the cumulative amount of levodopa administered. Both the IDI schedule and the LDR decay rate may reflect the ability of nigrostriatal neurons to store and to release dopamine formed from the exogenous precursor. The assessment of the LDR to levodopa by subacute tests is useful for establishing the appropriate dose of the drug, as well as for developing levodopa sparing strategies in PD patients.

Aged↗
PubMed1995

Motion perception deficits from midline cerebellar lesions in human.

Although visual motion processing is commonly thought to be mediated solely by visual cortical areas, this human lesion study suggests that the cerebellum also has a role. We found motion direction discrimination deficits in a group of patients with acute midline cerebellar lesions. Unlike normals and patients with hemispheric cerebellar lesions, these patients with midline lesions were unable to discern a global motion vector in a local stochastic motion display. This resembles the perceptual defect reported following cortical area MT lesions in primates. This motion perception deficit may result from damage to a cerebellar mechanism involved in perceptual stabilization. Disruption of this comparator mechanism is sufficient to produce a severe motion perception deficit even though cortical visual processing mechanisms are still intact.

Adult↗
PubMed1995

Motion and shape perception in cerebral akinetopsia.

Motion cues serve many purposes in primate vision. Consequently, akinetopsia, a defect of movement perception due to cerebral lesions, would be expected to comprise a range of motion-related defects. To address this issue we explored further the perceptual profiles in akinetopsic subject L.M. who has motion perception deficits due to extensive bilateral lesions of the dorsolateral visual association cortex that spare primary visual cortex, area V1. We used several different experimental procedures. Using random-dot motion stimuli, we showed that L.M. can still perceive global coherent motion and discriminate motion direction, yet these abilities fail even at moderate levels of background noise. L.M. also viewed a two-frame apparent (phi) motion stimulus known as a Ternus display. Her performance on this test suggests defective 'long-range' apparent motion mechanisms. These results are clearly in agreement with previous reports. Additional experiments showed that L.M. can still perceive 2-D shape and 3-D structure-from-motion (SFM). However, like motion direction discrimination, these abilities broke down at moderate levels of moving and stationary noise. Surprisingly, L.M. also had trouble perceiving 2-D shapes defined by non-motion signals including 'on' and 'off' transients, dynamic and static binocular disparity, and static texture cues. Our findings highlight the role of the visual association cortex in extracting salient information from noise.

Adult↗
PubMed1995

A phase I study of intravesical continuous perfusion of recombinant interleukin-2 in patients with superficial bladder cancer.

A Phase I study was started to evaluate the locoregional and/or systemic toxic effects of the continuous perfusion of recombinant interleukin-2 (rIL-2) in superficial bladder cancer. Three different dose levels were used: 3 x 10(6) IU/day (3 patients), 9 x 10(6) IU/day (3 patients) and 27 x 10(6) IU/day (3 patients). Two patients (one treated with 3 x 10(6) and another with 27 x 10(6) IU/day of rIL-2) had hematuria after the end of the treatment, one patient had fever (grade I) and 7 of 9 patients experienced hypotension (grade I-II). All effects were not dose related. Routine laboratory tests indicated that no significant variations of biochemical parameters occurred. A phenotypic analysis of white blood cells detectable in the bladder, showed an evident locoregional activation of lymphoid cells. In particular, T lymphocytes expressed activation antigens (such as CD25 and HLA-DR) following treatment with rIL-2. A 6- to 12-month clinical follow-up, showed that all patients but one (which recurred after 5 months) are alive and disease-free. This therefore indicates that the locoregional perfusion of rIL-2 is safe and gives clinical results similar to those obtained using Calmette-Guérin bacillus locoregional instillation, in patients who underwent a transurethral resection of superficial bladder cancer.

Administration, Intravesical↗
PubMed1995

Cloning and expression of an endothelin receptor subtype B from human prostate that mediates contraction.

Recent evidence suggests a role for endothelin (ET) in contraction of human prostate [J. Urol. 149:495-499 (1993)]. Although both ETA and ETB receptors have been shown to mediate contraction of smooth muscle, the molecular identity of the contractile ETB receptor is controversial. The aim of this study was to examine the receptor subtype that mediates ET-induced contraction in prostate from patients with benign prostatic hyperplasia. Saturation binding with 125I-ET-1 and 125I-ET-3 in prostate stromal cells (PSC) indicated the presence of receptors with subnanomolar affinity for these radioligands, with equivalent receptor densities. Inhibition of specific 125I-ET-1 or 125I-ET-3 binding in PSC revealed a rank order of potency of ET-1 - ET-3 = sarafotoxin S6c >> BQ-123. These data are consistent with a predominance of ETB receptors in PSC. The functional effects of ET stimulation of PSC were examined in a collagen gel contraction assay. ET-1 and ET-3 caused contraction of underlying collagen gel matrices with EC50 values of 0.4 +/- 0.04 and 0.7 +/- 0.2 nM, respectively. To determine the molecular nature of the contractile ETB receptor in PSC, reverse transcription-polymerase chain reactions were conducted with oligonucleotide primers to the 5' and 3' ends of the coding sequence of the full length human ETB receptor. DNA sequence analysis of the 1.3-kilobase DNA product showed 99% homology to other human ETB receptor cDNAs. The encoded protein has a deduced amino acid sequence identical to that of other human ETB receptors, with the exception of two conservative substitutions. Expression of the PSC ETB cDNA in COS-7 cells resulted in a binding profile similar to that observed in parent cells. Polymerase chain reaction analysis revealed the presence of prepro-ET-1 mRNA in PSC. Collectively, these data indicate that PSC from patients with benign prostatic hyperplasia express ETB receptors that mediate ET-induced contraction.

Amino Acid Sequence↗
PubMed1995

Hemangioma of the rib. A case report.

A case of hemangioma of the left twelfth rib is presented. clinical presentation, radiologic appearance and differential diagnosis with other vascular tumors of the bone are discussed, along with a review of the literature.

Bone Neoplasms↗
PubMed1994

Ureterouterine fistula as a complication of cesarean section.

A rare case of ureterouterine fistula caused by a complication of cesarean section after a normal pregnancy is reported. The patient presented with a urinous seeping into the vagina, and the fistula was diagnosed preoperatively on urography and computerized tomography. Treatment consisted of a 2-stage surgical approach, including percutaneous nephrostomy and subsequent ureteral reimplantation.

Adult↗
PubMed1994

Hallucinations following occipital lobe damage: the pathological activation of visual representations.

Neuropsychological investigation of hallucinations may provide insight into the nature of these subjective phenomena, as well as inform theories of perception and recall. We studied a man who described continuous visual hallucinations of object fragments (e.g., lines, corners, patterns) in the left visual field following a stroke in the right occipital cortex. The subject performed normally on standardized measures of visual perception and other cognitive abilities. He had no personality disturbance, and EEG during hallucinations was normal. Review of our records of 211 cases with focal lesions involving visual cortex revealed 5 patients with similar complaints. The hallucinatory experience of such patients probably reflects pathological activation of neural ensembles in the regions bordering an occipital lesion. These regions are presumed to contain records of visual feature fragments which are co-activated by feedback projections in the earliest visual association cortices, where they produce meaningful patterns during normal recall.

Aged↗
PubMed1994

Insulin-like growth factor-I (IGF-I) and its binding protein IGFBP-4 in human prostatic hyperplastic tissue: gene expression and its cellular localization.

It has been previously reported that 1) type I insulin-like growth factor (IGF) receptors are present in the human prostatic tissue; 2) IGF-I receptors are mainly localized in the epithelial cells; 3) IGF-I is a mitogen for prostatic epithelial cells in culture; and 4) IGF-binding proteins (IGFBPs) are released by these cells in the conditioned medium. To add information on the mechanism of IGF-I action in the human prostate, we studied the expression and cellular localization of mRNA encoding IGF-I and IGFBP-4 in human prostatic hyperplastic (BPH) tissue. Northern analysis of total RNA extracted from BPH tissues with cDNA probes containing the entire coding regions for IGF-I and IGFBP-4 documented the presence of multiple IGF-I mRNA transcripts with lengths of 7.5, 1.7, 1.3, and 1.1 kilobases and a single 2.1-kilobase transcript of IGFBP-4 mRNA. In situ hybridization with the cDNA probes used for Northern analysis and with cRNA probes synthesized from the respective cDNA demonstrated that IGF-I mRNA was only localized in the stromal cells, whereas IGFBP-4 mRNA was predominantly expressed by epithelial cells. In addition, immunoreactive IGF-I was measured in BPH tissue extracts after acidification and reverse phase chromatography. The mean (+/- SD) IGF-I content of six BPH tissues was 28.1 +/- 4.0 ng/g tissue. Our results suggest that in the human prostate, the locally secreted IGF-I exerts its principal biological effects with a paracrine mode of action and demonstrate that IGFBP-4 is mainly expressed by IGF-I target cells.

Carrier Proteins↗
PubMed1994

Motion perception in optic neuropathy.

We tested motion perception in 15 eyes of 13 patients with optic neuropathy. Eleven of the eyes had optic neuritis. The motion perception paradigm tested subjects' ability to discriminate the direction of a global coherent motion signal amid varying levels of background noise. The results showed defective motion processing in eight of the 15 eyes. This defect was not due to low visibility (poor spatial resolution), since 11 of the 15 eyes had Snellen acuities of 20/20 or better. Neither was impaired motion perception due to decreased luminance sensitivity, since attenuating the display signal by 2.1 log units (0.6 units more than the worst relative afferent pupillary defect in any patient) in five normal eyes had no effect. Motion perception and critical flicker fusion were independent of each other. Given proposals that both depend exclusively on the same M, or transient, channel, we had not predicted this double dissociation between flicker and motion perception.

Adult↗
PubMed1994

[Benign fibrous mesothelioma of the pleura].

The authors report 4 cases of patients with benign fibrous mesothelioma of the pleura, an extremely rare pathology (not more than 500 cases reported to date in the literature), and discuss biological behaviour, diagnosis and surgical treatment. Benign fibrous mesothelioma is generally diagnosed by chance during chest x-ray given that it is paucisymptomatic; diagnostic procedures include thoracic CT (which may be supplemented by transthoracic needle biopsy) and bronchoscopy. Treatment is surgical and consists of exeresis of the neoplasia; prognosis is excellent and cases are reported in the literature of 24-year follow-up without recurrence. Lastly, the authors underline the importance of modern immunohistochemical techniques which help the surgeon to formulate a precise diagnosis and to differentiate benign fibrous mesothelioma.

Adult↗
PubMed1994

Capsaicin-induced gastric mucosal hyperemia and protection: the role of calcitonin gene-related peptide.

BACKGROUND: Topical capsaicin augments gastric mucosal blood flow and is cytoprotective. This phenomenon is blocked by nitric oxide (NO) synthase and cyclooxygenase inhibition. Capsaicin-sensitive neurons store and release calcitonin gene-related peptide (CGRP). The purpose of this investigation was to study the effects of a CGRP antagonist on capsaicin-induced hyperemia and protection and to determine the role of NO and the cytoprotective prostaglandin PGE2 in this process. METHODS: The glandular stomachs in male Sprague-Dawley rats (280 to 350 gm) were chambered with the blood supply intact. Animals were divided into four groups. Normal saline solution (group 1) or the CGRP antagonists hCGRP8-37 (groups 2 through 4, 0.047 mg/ml) were continuously infused intraarterially via a retrograde splenic artery catheter at a rate of 0.034 ml/min after rats were given an intravenous bolus of either NSS (groups 1 and 2), L-arginine (group 3), or D-arginine (group 4) (200 mg/kg). The gastric mucosa was then topically exposed to normal saline solution (pH 7.4), followed by 160 mumol/L capsaicin and then 100 mmol/L acidified taurocholate (pH 1.2), each for 15 minutes. Gastric mucosal blood flow (ml/min/100 gm tissue) was continuously measured (laser Doppler) and mucosal injury was assessed. Luminal PGE2 production was measured during the bile acid injury period by radioimmunoassay. RESULTS: The CGRP antagonist hCGRP8-37 significantly inhibits capsaicin-induced hyperemia and its associated mucosal cytoprotection and also significantly decreases luminal mucosal PGE2 production. Pretreatment with L-arginine, but not D-arginine, reverses these effects of CGRP antagonism. CONCLUSIONS: CGRP is a mediator of capsaicin-induced hyperemia and protection. This effect may be dependent on both NO and PGE2 production.

Animals↗
PubMed1993

Color perception profiles in central achromatopsia.

Central achromatopsia is an impairment of color perception caused by damage to the visual association cortex. Its psychophysical underpinnings remain poorly defined. We report our attempt to characterize the defect along critical dimensions of color space, taking advantage of the same standardized tasks that allow detailed profiles in patients with retinal cone defects. We studied two patients. The results in patient 1 showed that perceptual color space was collapsed along the red-green (R-G) and short-wavelength-sensitive cone (S-cone) dimensions but that discriminations along achromatic dimensions were relatively preserved. Additional observations showed that the defect was dependent on target size, and that processing of surface and light source effects that differ from color (eg, transparency) was intact. Patient 2 showed a less severe color processing defect involving signals arising from the S-cones of the retina, although an R-G defect was also present. The profiles in these two patients demonstrate that central achromatopsia encompasses a range of color processing impairments with varied psychophysical characteristics.

Adult↗
PubMed1993

[Non surgical treatment of benign prostatic hypertrophy: phytotherapy].

Pharmacological treatment of voiding disorders due to benign prostatic hypertrophy offers a wide variety of pharmacological options. Phytotherapy represents one of the oldest drug used in the treatment of BPH. In the last decade, many studies have been performed to demonstrate efficacy and tolerability of this drug. We report a short literature review on mechanism of action and objective and subjective results of treatments with plant extracts. We report on a comparation between literature data and data of our trials. Safety, tolerability and subjective results seems to indicate that plant extract are still a good pharmacological option in the treatment of BPH micturitional disorders.

Humans↗
PubMed1993

'Bálint's syndrome' and associated visuospatial disorders.

There are several objections to the need for the designation 'Bálint's syndrome'. The full syndrome is generally associated with a wide variety of behavioural disturbances outside Bálint's original triad that may confound the interpretation of their supposed defect. It embeds itself in the hemineglect syndrome, violating the principle of autonomy for a syndrome. Individual components of the triad, particularly simultanagnosia, may represent relatively broad categories that subsume other combinations of defects of widely different degrees of severity. The diagnosis fails to predict a consistent site of anatomical impairment, and the main proposed mechanism is not sound. Our experience with a registry of patients with focal brain lesions and well-documented behavioural impairments (Palca, 1990), now numbering over 1500 individuals, tends to support these generalizations.

Agnosia↗