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M Zaharia

Publications and source records attributed to M Zaharia.

At least 19 recordsLinked to original sources
PubMed2001

Fractionated half-body irradiation (HBI) for the rapid palliation of widespread, symptomatic, metastatic bone disease: a randomized Phase III trial of the International Atomic Energy Agency (IAEA).

PURPOSE: To find the fastest and most effective/efficient method to economically deliver fractionated half-body irradiation (HBI) for widespread (WS), symptomatic, metastatic bone cancer. METHODS AND MATERIALS: A Phase III trial with 3 HBI arms: (Arm A) Control (15 Gy/5 fractions/5 days); (Arm B) Hyperfractionation (HF) (8 Gy/2 fractions/1 day); (Arm C) Accelerated HF (12 Gy/4 fractions/2 days). Six countries randomized 156 patients (all with WS bone metastases): 51, 56, and 49 patients to Arms A, B, and C, respectively. There were 72 (46%) breast, 50 (32%) prostate, 9 (6%) lung, and 25 (16%) miscellaneous primary tumors. Initial performance status (PS) was 1-2 in 101 (65%) and PS 3-4 in 55 (35%). The lower, upper, and middle halves of the body were treated 79, 68, and 9 times. RESULTS: Pain relief was seen in 91% of patients (45% complete [CR] and 46% partial [PR]) within 3-8 days. Overall (OS), median (MST), and pain-free (PFS) survival was 174, 150, and 122 days. Breast tumors had a higher OS (279 days) than that of other primary tumors, but when analyzed by treatment, was not significantly different than prostate tumors in Arm A. No survival differences were found in patients with PS 1-2 vs. 3-4, CR vs. PR, bone with/without visceral metastases, or by the number of metastases (< or > 15 bone lesions). Quality of life (QOL) assessed by the percent of the remaining life free of pain was 71%; furthermore significant improvements in PS, pain, and narcotic scores were seen after HBI. Toxicity was very acceptable (41% none, 50% mild/moderate, 12% severe but transitory); more was seen with upper HBI. CONCLUSION: In terms of response, time to response, OS, MST, PFS, QOL, and toxicity, schedules for Arms A and C were similar for all but prostate primaries. Schedule for Arm B, which delivered the lowest biologic dose in the shortest time, had significantly worse results in pain relief, OS, MST, PFS, and QOL. Results indicate that, for most primary tumor types (except prostate), delivering two HBI daily doses of 3 Gy in 2 consecutive days is as effective as delivering a daily dose of 3 Gy for 5 consecutive days. Thus, this is a faster and much more convenient HBI schedule for the palliation of pain in widespread cancer.

Bone Neoplasms↗
PubMed1996

Stressor-induced alterations of the splenic plaque-forming cell response: strain differences and modification by propranolol.

The effects of stressor application on the splenic plaque-forming cell (PFC) response was assessed in two strains of mice: the BALB/cByJ strain, which is highly responsive to stressors; and the more hardy DBA/2J strain. Both strains exhibited a peak PFC response 120 h following administration of sheep red blood cells (SRBC; 5 x 106 cells). Stressor exposure reduced the immune response; however, the appearance of such an outcome was dependent upon the time at which the stressor was applied relative to SRBC inoculation. In DBA/2J mice, foot-shock applied either immediately after SRBC inoculation or at the time of the peak immune response (120 h) resulted in suppression of the PFC response. In BALB/cByJ mice, both stressor severities provoked an immunosuppression when applied 120 h after inoculation, but when applied 96 h after immunization only foot-shock reduced the PFC response. At other intervals, the stressors were without effect. Pretreatment with the beta-norepinephrine antagonist propranolol precluded the immunosuppression elicited by a stressor applied 96 h after inoculation, but did not affect the reduction of the PFC response elicited by a stressor applied 120 h after inoculation. It is suggested that several factors may contribute to stressor-provoked alterations of the immune response, and that the contribution of these factors vary over the course of an immune response being mounted.

Adrenergic beta-Antagonists↗
PubMed1994

Selective effects of retinal dopamine depletion on partial ischemia-induced electroretinographic hyperresponses in rabbits.

The interaction of retinal dopamine depletion and partial ischemia on the a- and b-wave amplitudes and implicit times of the electroretinogram was examined in adult pigmented rabbits. Seven days after 6-hydroxydopamine treatment, which resulted in a depletion of the amine, partial retinal ischemia was induced by raising the intraocular pressure. As expected, moderate elevation of intraocular pressure produced increases in both a- and b-wave amplitudes. Amplitude hyperresponses were significantly reduced in dopamine-depleted retinas. These reductions were more prominent with relatively lower intensities. However, response delays were not shortened but lengthened by 6-hydroxydopamine pretreatment. Together, these results point to a selective role of dopamine in partial retinal ischemia induced by moderate elevation of intraocular pressure in rabbits.

Animals↗
PubMed1994

Effects of dextromethorphan on ischemia induced electroretinogram changes in rabbit.

The present study was undertaken to determine whether dextromethorphan (DM), a potent N-methyl-D-aspartate antagonist, could attenuate the effects of ischemia on rabbit ERG. Retinal ischemia was induced by increasing intraocular pressure to 120 mm Hg for 30, 60, or 90 min. DM was intravenously administered before ischemia and maintained throughout the entire experimental period. ERGs were recorded prior to, during, and after ischemia. The results indicate that the b-wave hyperresponses and the delays in implicit times induced by 30 min. ischemia were suppressed by the administration of DM. Similar findings were obtained when ischemia lasted for 60 min, except that DM did not improve delayed implicit times, suggesting that cellular injury is still present. ERG changes resulting from 90 min ischemia were not reversed by DM treatment. Effects of DM treatment on a-wave were less prominent. Together, our results further support that DM can to some extent alleviate ischemic injury in the rabbit retina.

Animals↗
PubMed1993

Dextromethorphan attenuates the effects of ischemia on rabbit electroretinographic oscillatory potentials.

Dextromethorphan has been shown to protect against ischemic tissue damage. We investigated the effects of dextromethorphan on electroretinographic oscillatory potentials in retinal ischemia. Retinal ischemia was induced in rabbits by increasing intraocular pressure to 120 mm Hg for 30, 60 or 90 minutes. Dextromethorphan was intravenously administered before ischemia and maintained throughout the whole period of experiments. Oscillatory potentials were recorded before and during ischemia as well as 4 hours of recirculation after ischemia. As expected, all oscillatory potentials were decreased after 60 and 90 minutes of ischemia. However, after 30 minutes of ischemia followed by 4 hours of recirculation, amplitudes of P2 were elevated whereas those of P3 and P4 were decreased with normal P1 amplitudes. Dextromethorphan administration diminished the effects of 30 minutes of ischemia on oscillatory potentials and partially attenuated the effects of 60 minutes of ischemia, whereas the effects of 90 minutes of ischemia could not be reversed by dextromethorphan treatment. These results indicate that electroretinographic oscillatory potentials could be useful indicators to evaluate retinal function in the ischemic condition and that dextromethorphan can attenuate the effects of relatively short periods of ischemia on rabbit electroretinographic oscillatory potentials.

Acute Disease↗
PubMed1993

Effects of calcitonin gene-related peptide on the rabbit electroretinogram.

In order to better understand the role of Calcitonin gene-related peptide (CGRP) in mammalian retina, the dose related effects of human CGRP (hCGRP) on rabbit electroretinogram (ERG) were examined in the present study. CGRP was administered intraocularly in doses of 0.1, 1.0 and 10.0 micrograms. ERG A- and B-wave as well as oscillatory potentials (P1, P2, P3 and P4) were recorded. The highest dose of CGRP (10.0 micrograms) significantly increased the amplitudes of the A-wave and OP components (P1, P2, P3 and P4) produced by relatively high stimulus intensity. The same dose of the peptide also enhanced B-wave amplitude at all intensities studied. The effects of the intermediate dose of CGRP (1.0 microgram) on the B-wave amplitudes were dependent on stimulus intensities. B-wave amplitudes at high stimulus intensities were not affected by 1.0 microgram of CGRP but were significantly increased with relatively lower stimulus intensities. The amplitudes of P3, one of OP components, were significantly increased. However, amplitudes of A-wave and other OP components (P1, P2 and P4) were not affected by 1.0 microgram CGRP. The lowest dose of the peptide (0.1 microgram) did not affect any amplitudes of ERG components. Implicit times of A-wave, B-wave and OP components were not significantly affected by the different doses of CGRP. Taken together, these results indicate that CGRP may play a functional role in modulating retinal responses to photic stimulation.

Animals↗
PubMed1993

Effects of experimentally induced ischemia on dopamine metabolism in rabbit retina.

PURPOSE: To determine the role of dopamine in experimentally induced retinal ischemia. Experiment 1 was designed to study the effects of ischemic levels on dopamine (DA) metabolism. Experiment 2 evaluated the effects of ischemic duration on DA metabolism. The effects of recirculation time after ischemia on DA metabolism were investigated in experiment 3. METHODS: Ischemia was produced by raising intraocular pressure (IOP) in rabbits. Three levels of ischemia were used--level A, level B, and level C--representing 50%, 75%, and 100%, respectively, of the IOP necessary to produce total ischemia. Retinal levels of DA and its main metabolites, homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC), were measured by high-performance liquid chromatography with electrochemical detection. RESULTS: Experiment 1 showed that at ischemic level B, DA contents were significantly reduced, but neither DOPAC nor HVA concentrations were altered. The reductions of retinal DA, DOPAC, and HVA concentrations were seen at level C without altering the ratio index. Level A ischemia did not alter DA metabolism. In experiment 2, significant reductions in DA, DOPAC, and HVA concentrations were found at both 30 and 60 minutes in the ischemic group, whereas the ratio DOPAC/DA and (HVA + DOPAC)/DA were significantly decreased only in the 60-minute ischemic group. Five-minute total ischemia did not alter DA metabolism. In experiment 3, concentrations of DA were still significantly decreased at 30 minutes of recirculation after ischemia, but DOPAC and HVA levels were back to normal. However, the ratios of DOPAC/DA, HVA/DA, and (HVA + DOPAC)/DA were significantly elevated. After 90 and 240 minutes of recirculation, retinal DA contents had returned to normal values, but DOPAC and HVA concentrations as well as all ratio indices of DA metabolism were still enhanced. CONCLUSION: Dopamine metabolism is altered during and after retinal ischemia. Dopamine may play a contributing role in ischemia.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

Incidence of regional lymph node metastasis in operable osteogenic sarcoma.

Records of 182 consecutive patients with the diagnosis of operable osteogenic sarcoma, treated between 1954 through 1980 by the Breast, Bone and Mixed Tumors Department of the Instituto Nacional de Enfermedades Neoplasicas (Lima, Peru), were reviewed to study the incidence of regional lymph node metastases in this disease. All the patients included in this study had radical surgery, which means the complete resection of the bone where the tumor is located, including the proximal joint, which permitted excision of the regional lymph nodes. Nineteen patients (10.4%) had evidence of sarcoma metastatic to draining lymph nodes. A comprehensive analysis of the literature shows that the incidence of metastasis to the lymph nodes in this study, is higher than those cited in a review of the literature, probably due to the policy in the management of osteogenic sarcoma in our institution, during the period of study.

Adolescent↗
PubMed1989

Postoperative radiotherapy in the management of cancer of the maxillary sinus.

This report comprises 149 patients with carcinoma of the maxillary sinus treated with radical surgery and postoperative radiotherapy (5500 to 6000 cGy in 6 weeks) between 1963 and 1980 at the Instituto Nacional de Enfermedades Neoplasicas of Lima. Permanent local control was observed in 67.1% of the cases with a 5-year actuarial survival of 36.2% and a corrected survival for death not due to cancer of 42.3%. The ultimate local and distant failures were 61%. Data were analyzed regarding stage of the disease, radiotherapeutic technique and its influence on local control, complications, and patterns of relapse. The data indicate that the stage of the tumor influences survival. Because of the natural history of this disease, local control is paramount.

Adenocarcinoma↗
PubMed1987

Radiotherapy in the management of locally advanced breast cancer.

A retrospective study of 484 patients with locally advanced cancer of the breast treated with irradiation alone revealed a partial or complete response in 64% of the patients, with a mean duration of 13 months. The 5-year survival was 21.9% for the entire group of patients; 32% for patients responding, and 5% for non-responding patients. The data suggests that the size of the tumor and the age of the patients influence the quality of response. The results indicate that radiotherapy adequately controls local disease in a significant number of patients but systemic treatment is needed for better disease control.

Adult↗
PubMed1987

Lobular delayed choroidal perfusion as an early angiographic sign of diabetic retinopathy: a preliminary report.

Between January 1982 and December 1983 stereo colour photography covering 10 standard fields of 30 degrees and fluorescein angiography were performed in 64 consecutive patients with diabetes mellitus who had no clinical evidence of diabetic retinopathy. Fifty-two patients were excluded on the basis of the slightest photographic or angiographic evidence of retinopathy or any other ocular disease. Electroretinogram oscillatory potentials were recorded in the remaining 12 patients. Four of the 12 had normal oscillatory potentials, colour photographs and angiograms, while 8 had angiographic evidence of lobular delayed choroidal perfusion and abnormal oscillatory potentials. Although only a small number of patients in the preclinical stages of diabetic retinopathy were studied, the results warrant that further attention be given to lobular delayed choroidal perfusion, which may represent early evidence of choroidal involvement in diabetic retinopathy.

Choroid↗
PubMed1986

Rod-cone differences in response to retinal ischemia in rabbit.

Two series of experiments are reported on incremental increases of ischemia and monitoring of recovery from total ischemia of varying duration. In the first, rods show hyper-responses and cones do not; changes in amplitude and delays appear at higher levels of ischemia in cones than they do in rods. In the second series, cones do not recover up to control values with total ischemias of 30 min or more, while rods do recover and even show hyper-responses. Cones appear more resistant than rods to ischemia, but once affected do not recover as well as rods. Discussion proposes that these differences are specific to receptor systems of each rather than secondary to vascularization patterns.

Animals↗
PubMed1986

Postoperative whole lung irradiation with or without adriamycin in osteogenic sarcoma.

Thirty-six patients with histologically proven osteogenic sarcoma of the extremities, treated between September 1975 and April 1978, are the subject of this report. The primary tumor was treated with radical surgery. Patients received 2000 cGy whole lung irradiation postoperatively in an attempt to control micrometastases to the lung. Twenty-nine of the patients were given Adriamycin (60 mg/m2 IV every 6 weeks for a total dose of 550 mg/m2) in addition to the irradiation. The median, disease-free interval was 118 days for the seven patients treated with lung irradiation only. The median overall survival for these patients is 241 days, with one patient alive with disease. All patients developed lung metastasis. For the 29 patients treated with postoperative lung irradiation and Adriamycin, the median disease-free interval was 372 days, and the median overall survival is 843 days. Nineteen of the patients recurred (65.5%). The differences are statistically significant (p less than or equal to 0.003, median disease-free survival and p less than or equal to 0.03, median survival). This study supports the role of whole lung irradiation plus Adriamycin, in the control of micrometastases in osteogenic sarcoma of the extremities and suggests that additional clinical trials are warranted.

Adolescent↗
PubMed1986

Pattern and flash electroretinogram following increased intraocular pressure in pigeons.

We have observed an increase in time to peak and a decrease in amplitude for both the pattern electroretinogram (PERG) and the electroretinogram (ERG) in pigeons following an elevation in intraocular pressure (IOP). The changes in PERG were highly correlated to the changes in ERG. However, they differed in that significant changes from baseline values occurred at lower levels of IOP for PERG than ERG for the amplitude, and in some cases for the time to peak.

Animals↗
PubMed1986

Electroretinographic recovery from controlled total ischemia.

Three groups of animals were studied during the four-hour period following their recovery from total occlusion of retinal circulation for periods of 30, 60 and 90 minutes. During incremental increases of ischemia, recovery followed a pattern that is the reverse of that previously reported, inasmuch as wave amplitude is concerned. From total extinction, ERGs recovered and showed hyperresponses. Delays, however, behaved differently: they increased with recovery time--the opposite of what was expected. All signs were inversely proportional to the duration of ischemia. Sixty minutes of occlusion appears to be a threshold beyond which ERGs do not recover as well.

Animals↗
PubMed1984

Local control of osteogenic sarcoma by radiation and chemotherapy.

Sixteen patients with osteogenic sarcoma of limbs were treated with high dose methotrexate followed by leucovorin rescue, adriamycin and radiotherapy to the primary tumor. A post-treatment surgical biopsy was performed in 15 of the 16 patients. In 12 of 15 patients (80%), the follow-up biopsy was negative for active tumor. Complications of treatment were myelosuppression (16 cases), moist desquamation (13 cases), soft tissue necrosis (2 cases) local infection (2 cases), fibrosis (9 cases) and bone fracture (4 cases). The mean survival time in this group of patients was 712 days.

Adolescent↗
PubMed1984

Cobalt therapy prophylaxis of recurrence of T1 bladder cancer.

Eighteen patients with T1 transitional cell carcinoma of the urinary bladder were submitted to transurethral resection of the tumor, followed by Cobalt therapy (5,500 rads to the pelvis and 6,500 rads to the bladder in six weeks). The recurrence rate at three years follow-up was 33% (6/18). Recurrence of transitional cell carcinoma of the urinary bladder is a well known condition in stage O and A, even when low grade is present. Recurrence rates at one year as high as 84% (Loening et al., 1983) are reported in the current literature. In recent years many studies have been performed which were oriented to the use of intravesical chemotherapy in order to reduce the recurrence rate (Adolphs and Bastian, 1983; Huland, 1983; Loening et al., 1983; National Bladder Cancer Collaborative Group A, 1977; Rodriguez and Caserta, 1983; Zincke et al., 1983) of this tumor. We started a protocol on treatment of the transitional cell carcinoma of the urinary bladder in 1963. The protocol calls for transurethral resection of the tumor followed by Cobalt therapy. This is an interim report on stage T1 (stage A) with such a treatment.

Adult↗