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Biomedical subjects

R Rodriguez

Publications and source records attributed to R Rodriguez.

At least 109 records · Page 6Linked to original sources
PubMed1996

Ifosfamide and vinorelbine as first-line chemotherapy for advanced non-small cell lung carcinoma.

We evaluated the efficacy and toxicity of the novel combination of ifosfamide (IFX) and vinorelbine (VNB) as first-line chemotherapy in patients with stage IIIB and IV non-small cell lung cancer (NSCLC). Between March 1993 and November 1994, 44 patients (17 stage IIIB; 27 stage IV) received a regimen consisting of IFX, 2 g/m2 in a 1-h infusion, days 1-3; mesna, 400 mg/m2 in an i.v. bolus at hours 0 and 4 and 800 mg orally at hour 8, days 1-3; and VNB, 35 mg/ m2 in a 20-min infusion, days 1 and 15. During the first course only, a half dose of VNB (17.5 mg/m2) was administered on days 8 and 22. Courses were repeated every 28 days. Forty patients were fully evaluable for response, and 44 were assessable for toxicity. Objective regression was recorded in 13 of 40 patients (33%). No patient achieved a complete response. Thirteen patients presented a partial response (33%); 17 (42%) had no change; and progressive disease was observed in 10 (25%). The median duration of response was 10 months, and the median time to treatment failure for the whole group was 4 months. Median survival was 11 months. The dose-limiting toxic effect was myelosuppression. Leukopenia occurred in 25 patients (57%) and was grade 3 or 4 in 8 patients (18%). Twelve patients (27%) developed peripheral neurotoxicity, while five had mild IFX-induced CNS toxicity. Phlebitis was observed in 15 of 30 patients (50%) who did not have central implantable venous systems. The IFX-VNB combination exhibited an activity against NSCLC that was among the highest reported for non-cisplatin-containing regimens, with a toxicity profile that was easily managed.

Adult↗
PubMed1996

Further observations on the role of nitric oxide in the feline lateral geniculate nucleus.

We have examined the responses of a population of 77 cells in the dorsal lateral geniculate nucleus (dLGN) of the anaesthetized, paralysed cat. Here the synthetic enzyme for the production of nitric oxide, nitric oxide synthase, is found only in the presynaptic terminals of the cholinergic input from the brainstem. In our hands, iontophoretic application of inhibitors of this enzyme resulted both in significant decreases in visual responses and decreased responses to exogenous application of NMDA, effects which were reversed by coapplication of the natural substrate for nitric oxide synthase, L-arginine, but not the biologically inactive isomer, D-arginine. Nitroprusside and S-nitroso-N-acetylpenicillamine (SNAP), nitric oxide donors, but not L-arginine, were able to increase markedly both spontaneous activity and the responsiveness to NMDA application. Furthermore, SNAP application facilitated visual responses. Responses of cells in animals without retinal, cortical and parabrachial input to the LGN suggest a postsynaptic site of action of nitric oxide. This modulation of the gain of visual signals transmitted to the cortex suggests a completely novel pathway for nitric oxide regulation of function, as yet described only in primary sensory thalamus of the mammalian central nervous system.

Afferent Pathways↗
PubMed1996

The influence of nitric oxide on perigeniculate GABAergic cell activity in the anaesthetized cat.

We have tested the effect of iontophoretic application of the nitric oxide synthase inhibitor L-nitroarginine on the activity of a population of 53 perigeniculate (PGN) cells, recorded extracellularly in the anaesthetized paralysed cat. In all cells tested with visual stimulation during L-nitroarginine application (n = 15), the visually elicited responses were markedly reduced, on average by 63 +/- 15%, and there was a reduction in spontaneous activity too. This effect was blocked by co-application of the substrate for nitric oxide synthase, L-arginine, but not by the inactive D-isoform, although application of L-arginine alone was without effect. Pressure application of the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP) elevated both visual responses and spontaneous discharge, an effect also seen with a second nitric oxide donor, sodium nitroprusside (n = 12). The nitric oxide synthase inhibitor L-nitroarginine was applied to a sub-population of seven cells and it selectively decreased NMDA mediated excitation (reduction 80 +/- 14%) with little or no effect on the excitation mediated by alpha-amino-3-hydroxy-5-5-methyl-4-isoxazole-propionic acid (AMPA) or quisqualate (effects not statistically significant), and it had no effect (n = 7) on excitation mediated by the metabotropic agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD). Furthermore, application of SNAP also increased the magnitude of excitatory responses mediated by NMDA receptors. On a different population of seven cells, application of the new NO donor diethylamine-nitric oxide (DEA-NO) enhanced the actions of NMDA without an effect on responses to AMPA. These effects are qualitatively and quantitatively similar to those we have previously described for X and Y type cells in the dorsal lateral geniculate nucleus (dLGN), despite the known opposite effects of acetylcholine (ACh) application in the dLGN and PGN (ACh is co-localized with nitric oxide synthase at both sites). We propose that within the PGN nitric oxide acts to enhance transmission utilizing NMDA receptors selectively (thereby interacting with the globally inhibiting effect of ACh at this site) to enhance visual responses, reducing or removing the non-specific inhibitory drive from PGN to dLGN seen in the spindling activity of slow-wave sleep. These effects will act in concert with the facilitatory actions of both ACh and nitric oxide within the dLGN proper, and will thereby enhance the faithful transmission of visual information from retina to cortex.

Animals↗
PubMed1996

Treatment of posttransplant lymphocele with povidone-iodine sclerosis: long-term follow-up.

Percutaneous transcatheter sclerosis with iodate-povidone has been proposed as a treatment of posttransplant lymphocele. We treated 19 lymphoceles with iodate-povidone, 10 of them totally resolved and 6 promptly recurred. Three recurrences were treated conservatively and in 3 the treatment was repeated with success. Therefore, we have a low recurrence and retreatment rate. Our total resolution rate was 100%. Complications due to the treatment were rare. In the long term no patient has developed any renal or perirenal complication related to iodine sclerosis. We conclude that iodine sclerosis is a safe and effective treatment of posttransplant lymphocele. We think that surgical procedures must be reserved to collections adjacent to renal hilum or inaccessible for safe puncturing.

Follow-Up Studies↗
PubMed1996

Ifosfamide and vinorelbine as first-line chemotherapy for metastatic breast cancer.

PURPOSE: To evaluate the efficacy and toxicity of the combination of ifosfamide (IFX) and vinorelbine (VNB) as first-line chemotherapy in metastatic breast cancer (MBC). PATIENTS AND METHODS: Between August 1993 and August 1995, 45 patients with untreated MBC received a regimen that consisted of IFX 2 g/m2 by 1-hour intravenous (i.v.) infusion on days 1 to 3, mesna 400 mg/m2 by i.v. bolus at hours 0 and 4 and 800 mg/m2 orally at hour 8 on days 1 to 3, and VNB 35 mg/m2 by 20-minute i.v. infusion on days 1 and 15. Courses were repeated every 28 days. During the first course only, half-dose VNB (17.5 mg/m2) was administered on days 8 and 22. The median age was 53 years and 30 patients (67%) were postmenopausal. Dominant sites of disease were soft tissue in nine patients, bone in seven, and visceral in 29. RESULTS: Objective responses (ORs) were recorded in 25 of 43 assessable patients (58%; 95% confidence interval, 43% to 73%). Complete remissions (CRs) occurred in six patients (14%) and partial remissions (PRs) in 19 (44%). No change (NC) was recorded in 10 patients (23%) and progressive disease (PD) in eight patients (19%). The median time to treatment failure was 12 months and the median survival duration 19 months. Myelosuppression was the limiting toxicity, mainly leukopenia in 32 patients (74%). In contrast, anemia and thrombocytopenia were mild. Other significant toxicities included peripheral neuropathy in nine patients (21%), constipation in 15 (35%), and myalgias in 11 (26%). CONCLUSION: IFX/VNB is an active combination against MBC with moderate toxicity and deserves further evaluation.

Adult↗
PubMed1996

MR urography using HASTE imaging in the assessment of ureteric obstruction.

OBJECTIVE: The purpose of this study was to evaluate an MR sequence using half-Fourier acquisition single-shot turbo spin-echo (HASTE) imaging in the assessment of ureteric obstruction. SUBJECTS AND METHODS: We prospectively evaluated 111 kidneys in 56 consecutive patients with HASTE MR urography and compared that imaging technique with excretory urography. The HASTE sequence was used to acquire images in the axial, sagittal, and coronal planes while patients held their breath. Level of obstruction and ureteric diameter were assessed, and the time required to determine the level of obstruction by both techniques was noted. RESULTS: With HASTE MR urography, we correctly diagnosed obstruction in 41 (100%) of 41 kidneys. Of the obstructed kidneys in which the ureter was shown by both excretory urography and MR urography, agreement was high (kappa = .642) between the two imaging techniques regarding the level of obstruction. HASTE MR urography showed perirenal fluid in 20 (87%) of 23 acutely obstructed kidneys. HASTE MR urography showed the site of obstruction on the first 13-sec scan in 33 (80%) of 41 kidneys. CONCLUSION: HASTE MR urography accurately and rapidly shows the level and degree of ureteric obstruction. It can be used to differentiate between acute and chronic obstruction on the basis of its ability to show perirenal fluid.

Acute Disease↗
PubMed1996

Vascular neurosurgery: aneurysms, arteriovenous malformations, subarachnoid hemorrhage, and intracranial hemorrhage.

Cerebrovascular disease continues to be a major source of morbidity and mortality in our aging population. Endovascular therapy for the treatment of cerebral aneurysms and associated vasospasm is gaining credibility. Some arteriovenous malformations considered inoperable in the past can now be successfully treated using multimodality therapy. Quantitative measurement of cerebral blood flow is helping to identify patients at risk of ischemic events and defining new guidelines for intervention. New noninvasive imaging modalities may replace conventional angiography for surgical disease. Advances in technology continue to improve our ability to treat cerebrovascular disease prior to irreversible ischemic events.

Cerebral Hemorrhage↗
PubMed1995

Tumor vascularization, mitotic index, histopathologic grade, and DNA ploidy in the assessment of 114 head and neck squamous cell carcinomas.

BACKGROUND: Quantification of tumor vascularization recently has been shown to a parameter of potential clinical significance. Several basic and clinical studies have demonstrated that tumor growth correlates significantly with angiogenesis. METHODS: To determine the utility of quantification of tumor vascularization and mitotic index for the pathobiologic assessment of head and neck squamous cell carcinoma, a prospective study of 114 consecutively recruited primary neoplasms was performed. Tumors were also studied for differentiation, keratinization, nuclear atypia, growth pattern, inflammation, desmoplasia, vascular tumor emboli, and DNA content. RESULTS: In this cohort, tumor vascularization was correlated with mitotic index (P < 0.001), nuclear grade (P = 0.03), presence of tumor emboli in the peripheral microvessels (P = 0.05), and lymph nodal status (P = 0.03). A strong relationship between poor differentiation and high N classification (P < 0.001), differentiation and keratinization (P < 0.001) and tumor cell emboli and clinically involved lymph nodes (P = 0.01) was also observed. Emboli were more rare in laryngeal and oropharynx/oral cavity tumors than in hypopharynx/epilarynx (P = 0.02). CONCLUSIONS: This study indicates that tumor vascularization, differentiation, and tumor emboli in peripheral microvessel network are important histologic parameters in the assessment of squamous cell carcinoma of the head and neck.

Adult↗
PubMed1995

The current status of academic-mental health linkages in Rhode Island.

The purpose of this study is to describe the current status of academic-public mental health linkages in the State of Rhode Island by querying key informants concerning their opinions in the following areas: clinical orientation and preferred clinical interventions, specific approaches to academic-mental health linkages, training and educational opportunities, obstacles to a career working with persons who have persistent and severe mental illness, and recommendations to improve academic-mental health linkages. Forty-eight of sixty key informants, among them academics, mental health administrators, clinical practitioners and consumer advocates, responded to the mailed survey. More than half the respondents rated affective disorders, schizophrenia and substance abuse to be their highest concern as professionals; most subscribed to biological models of mental illness as well as a variety of prevailing treatment strategies employed in the care of persons with severe mental illness; generally they rated the current status of academic-mental health linkages to be low, but recommended a range of remedies to improve and increase collaborative efforts.

Community Mental Health Services↗
PubMed1995

Safety of pneumococcal revaccination.

Indications for pneumococcal polysaccharide revaccination include highest-risk patients vaccinated more than six years previously, but there is controversy regarding revaccination of patients with chronic medical conditions and revaccination of the elderly. The object of the study was to investigate whether revaccination with the pneumococcal polysaccharide vaccine would cause significant adverse reactions. 151 patients were revaccinated and completed a questionnaire concerning the 72 hours after the injection. Valid data were obtained from 127 patients. Mild systemic reactions varied from 4% to 8% and local reactions varied from 40% to 60%, which is not different from the reported reaction with the initial vaccination. This profile of adverse reactions after revaccination should minimize concerns about revaccination.

Aged↗
PubMed1995

Concealed umbilical stoma: description of a modified technique.

PURPOSE: We describe a technique for creating a concealed umbilical stoma. MATERIALS AND METHODS: The base of the umbilicus is used as a superiorly based skin flap that is incorporated into the spatulated stoma. Six patients have undergone diversion using this technique. The stoma was constructed from appendix in 4 cases, stomach in 1 and tapered ileum in 1. RESULTS: All patients achieved an easily catheterizable hidden umbilical stoma, are dry on clean intermittent catheterization and have had no stomatitis or peristomal hernia. CONCLUSIONS: This technique for creating a concealed umbilical stoma preserves the native appearance of the umbilicus and combines a superior cosmetic result with an easily catheterizable stoma.

Adolescent↗
PubMed1995

High-dose cisplatin with dipyridamole in advanced non-small cell lung cancer. A Grupo Oncológico Cooperativo del Sur study.

From March 1991 to October 1992, 41 patients with advanced non-small cell lung cancer (NSCLC) (20 stage IIIB and 21 stage IV) received a regimen consisting of cisplatin (CP) 100 mg/m2 i.v. days 1 and 8, and dipyridamole (DPD) 100 mg p.o. 75 minutes before CP, and then at hours 6, 12, and 18 as first-line chemotherapy. Cycles were repeated every 28 days for a total of 3. Median age was 56 years (range: 40-70). All patients had a performance status 0 to 1 and a weight loss < or = 10%. Squamous-cell carcinoma was diagnosed in 19 patients; adenocarcinoma in 16, and large-cell carcinoma in 6. A total of 37 patients were fully evaluable for response, whereas 39 were assessable for toxicity. No complete responses were observed: 5 patients (14%) achieved partial response; 23 patients (62%) showed no change, and progressive disease was observed in 9 (24%). The median time to treatment failure was 4 months, whereas median survival was 8 months. The average dose intensity received at the end of the third course of therapy was 46 mg/m2/week. There were no drug-related deaths. Toxicity was mild to moderate, with a high incidence of ototoxicity (54%) and emesis (67%). In conclusion, these results failed to demonstrate any significant advantage from a high-dose CP regimen modulated by DPD in patients with advanced NSCLC.

Adult↗
PubMed1995

Differential diagnosis and evaluation of the incidentally discovered renal mass.

Recent advances in technology, coupled with decreasing costs, have led to a substantial rise in the diagnosis of the incidentally discovered renal mass. In virtually all of these cases, the underlying signs and symptoms of an occult renal tumor were either absent or sufficiently minor as to escape the notice of the referring physician. Although the majority of the renal masses are benign renal cysts, many are indeterminate or frankly malignant. The evaluation of these tumors is typically completed with contrast-enhanced static or spiral computed tomography; however, ultrasound may be sufficient in many cases to definitively diagnose renal cysts. The size and location of these tumors often dictates treatment, and recently, less conservative management has found to be reasonably safe and effective. For instance, small localized tumors are now being considered for tumor enucleation, heminephrectomy or partial nephrectomy, even in the presence of an otherwise normal contralateral kidney. Recent innovations, including intraoperative sonography, have given the urologic surgeon an additional tool for complete evaluation of the indeterminate renal mass. These issues are discussed in detail, in order to achieve a rational approach to the differential diagnosis and evaluation of the incidental renal mass.

Biopsy, Needle↗
PubMed1994

Brain potentials and the availability of semantic and phonological codes over time.

ERPs were recorded from subjects performing semantic and rhyme matching tasks using either spoken words, printed words or pictures as stimuli. Mismatches enhanced N400 (in the semantic task) and N450 (in the rhyme task). Onset and peak latencies were shorter for N450 than for N400 with spoken words; this relationship was inverted for pictures. Thus these latencies could index availability of semantic and phonological codes. For printed words, the latencies were shorter for N400 than N450, a result that supports direct-access modes of reading with late phonological code activation. The longer latencies found for N400 and N450 to pictures could suggest longer initial decoding for pictures with respect to words.

Adolescent↗