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Biomedical subjects

G Schwartz

Publications and source records attributed to G Schwartz.

At least 73 records · Page 4Linked to original sources
PubMed1995

Modification of rhythmical jaw movements by noxious pressure applied to the periosteum of the zygoma in decerebrate rabbits.

The purpose of this study was to describe and quantify changes in the movement and EMG patterns caused by tonic noxious pressure on the periosteum of the zygoma during electrically induced rhythmic jaw movements in the decerebrate rabbit. Eight New Zealand rabbits were anesthetized with urethane. EMG electrodes were placed in the masseter and digastric muscles and a light was attached to the mandibular symphysis to track jaw movements. The animals were decerebrated and the anesthetic was discontinued. Rhythmic jaw movements were evoked by electrically stimulating the corticobulbar tracts (1-msec rectangular pulses, 50 Hz), in the absence and presence of tonic noxious pressure applied bilaterally to the zygomatic periosteum (range: 400-1500 kPa). The overall response to tonic noxious pressure was a statistically significant decrease in the frequency and amplitude of the rhythmic jaw movements and in the mandibular velocity during opening and closing. The slowing of the frequency was associated with a significant increase in the duration between muscle bursts. In those animals in which the jaw closing muscles were most active, there was a significant decrease in the area of the masseter muscle bursts during jaw closure. The changes in motor activity in response to the application of tonic noxious pressure are similar to those that have been reported for patients experiencing musculoskeletal pain, suggesting that pain modifies motor programs at the segmental level. Our data support the pain-adaptation model.

Animals↗
PubMed1995

Prognostic factors for prolonged progression-free survival with high-dose chemotherapy with autologous stem-cell support for advanced breast cancer.

PURPOSE: With a median observation time of 50 months from transplant, 13 (22%) of 62 women with metastatic breast cancer treated with high-dose chemotherapy at the Dana-Farber Cancer Institute (DFCI)/Beth Israel Hospital (BIH) remain progression-free. This study determined factors prognostic for prolonged progression-free survival (PFS). METHODS: From June 1988 to January 1992, women who responded to standard chemotherapy received high-dose cyclophosphamide, thiotepa, and carboplatin with autotransplantation. Data encompassing initial breast cancer diagnosis, metastatic presentation, and response to induction treatment were examined for correlations with improved PFS. RESULTS: The 5-year PFS rate for the entire group is estimated to be 21% (95% confidence interval [CI], 10% to 32%). For those patients who attained a complete response (CR) to induction therapy, the 5-year PFS rate is estimated to be 31% (95% CI, 0% to 63%). In univariate analyses, a single metastatic site, CR to induction therapy, prolonged interval from primary diagnosis to first metastases, estrogen receptor (ER)-negative tumors, and older age (> or = 40 years) were associated with prolonged PFS. In multivariate analyses, single metastatic site (P = .002) and attainment of a CR to induction chemotherapy (P = .04) were the most significant predictors for PFS, with a strong trend observed for an interval from primary diagnosis to onset of metastatic disease of 24+ months (P = .066). CONCLUSION: We and others have shown that 10% to 25% of women with metastatic breast cancer are progression-free after high-dose chemotherapy with autotransplantation. Those with chemosensitive disease, minimal tumor bulk, and a prolonged disease-free interval appear to benefit most. Emphasis should continue to focus on the development of more effective cytotoxic regimens and biologic approaches to increase the percentage of patients who may benefit from this approach.

Adolescent↗
PubMed1995

Phase I study of high-dose ifosfamide, carboplatin and etoposide with autologous hematopoietic stem cell support.

More effective high-dose combination regimens are needed which have broad cytotoxic activity, steep dose-response relations and non-overlapping non-hematologic toxicities (to allow administration of full doses of each agent). This study was designed to define the dose-limiting toxicities and maximum tolerated doses of ifosfamide, carboplatin and etoposide (ICE) with hematopoietic stem cell support. Ifosfamide and carboplatin were initially fixed at 75% and 80% of the single agent maximum tolerated doses, respectively, and etoposide added to the combination. After the dose-limiting toxicity of etoposide was reached, its dose was fixed and ifosfamide and carboplatin were individually dose escalated as tolerated. All agents were given by 96h continuous infusion (days -7 to -3). Autologous marrow, with or without peripheral blood progenitor cells, was reinfused on day 0. Forty eight adults with advanced malignancies were enrolled in cohorts of three to five patients. At the maximum tolerated doses of ifosfamide 16 g/m2, carboplatin 1.8 g/m2 and etoposide 1.2 g/m2, renal toxicity precluded further dose escalation. Two patients died of organ (renal, CNS) toxicity (4%). Renal toxicity was particularly prominent in patients with prior cisplatin exposure. An early chemotherapy-stopping rule was developed, supported by pharmacologic analysis, which resulted in immediate discontinuation of ifosfamide and carboplatin if the serum creatinine, monitored twice daily during chemotherapy, exceeded 1.5 mg/dl and was > 0.5 mg/dl above baseline. High-dose ICE is well tolerated if serum creatinines are carefully monitored during chemotherapy administration. The early chemotherapy-stopping rule may enhance safety of the regimen but requires validation by addition correlation with pharmacokinetic data for each of the chemotherapeutic agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A phase II trial of alpha-interferon and 5-fluorouracil in patients with advanced carcinoid and islet cell tumors.

BACKGROUND: 5-Fluorouracil (5-FU) has shown modest single-agent activity in patients with carcinoid or islet cell tumors. Alpha interferon (alpha-IFN) has also shown modest single agent activity in these diseases, although biologic responses have been far more prevalent than have objective tumor regressions. The combination of alpha-IFN and 5-FU has demonstrated enhanced activity in several gastrointestinal malignancies. METHODS: Twenty-one patients with advanced neuro-endocrine tumors (14 with carcinoid tumors, 7 with islet cell carcinomas) were treated with alpha-IFN and 5-FU in a Phase II study. 5-Fluorouracil was administered by intravenous bolus injection at an initial dose of 400 mg/m2/day for 5 consecutive days. After a 1-week break, 5-FU then was administered weekly by intravenous bolus at a dose of 750 mg/m2. Alpha interferon administration was begun on Day 1 of 5-FU at a daily dose of 3 x 10(6) U subcutaneously and continued for the duration of the trial. RESULTS: Of the 14 carcinoid patients with carcinoid tumors, 1 experienced a partial response (7%; 95% confidence interval [CI] 0-20%) that lasted for 6 months. Eight of the patients with carcinoid tumors achieved stable disease for a median of 6 months (range, 2-10 months). One of the patients with islet cell tumors (14%; 95% CI 0-39%) achieved a partial response that persisted after 8 months; 4 patients with islet cell tumors had stable disease for a median of 13 months (range, 4-27+ months). Even at this relatively low dose of alpha-IFN, 14 of 21 patients required a dose reduction in the alpha-IFN (13 for fatigue, 1 for ataxia). Three patients experienced myelosuppression of greater than Grade 3, and three patients had diarrhea of greater than Grade 3. One patient experienced dose-limiting hand-foot syndrome. CONCLUSIONS: These results suggest that the combination of 5-FU and alpha-IFN does not have any clear superiority over the individual agents alone; 5-FU appears to reduce patient tolerance of alpha-IFN when given on a daily schedule. Further investigations are needed to identify active agents in the treatment of neuroendocrine malignancies.

Adenoma, Islet Cell↗
PubMed1994

Phase I trial of an interleukin-2 fusion toxin (DAB486IL-2) in hematologic malignancies: complete response in a patient with Hodgkin's disease refractory to chemotherapy.

BACKGROUND: DAB486IL-2 is a recombinant fusion toxin in which the native diphtheria toxin-receptor binding-domain has been replaced with human interleukin-2 (IL-2). This molecule is specifically cytotoxic in vitro within 30 minutes for cells that express the high-affinity IL-2 receptor (IL-2R). METHODS: This was a Phase I/II study of DAB486IL-2 as a brief infusion in 15 patients with refractory lymphoid malignancies. Five patients per cohort received DAB486IL-2 as a 30-60 minute intravenous infusion at dose levels of 0.075, 0.115, and 0.2 mg/kg daily for 5 days. RESULTS: The maximal tolerated dose (MTD) of DAB486IL-2 was determined to be 0.2 mg/kg daily on the basis of hypersensitivity-like symptoms and reversible hepatic transaminase elevations. Other adverse effects included mild creatinine elevations, proteinuria, and hypoalbuminemia. The presence of antibodies to diphtheria toxin or DAB486IL-2 was correlated with hypersensitivity-like effects but did not prevent an antitumor effect. One complete response was observed in a patient with Hodgkin's disease in relapse with bilateral pulmonary nodules after autologous bone marrow transplantation. He remains free of disease more than 2 years after completion of therapy. CONCLUSIONS: The dramatic antitumor response seen in one patient and the relative tolerability of DAB486IL-2 indicates the potential utility of this targeted agent in IL-2-expressing hematologic malignancies.

Adult↗
PubMed1994

Does curriculum make a difference? A comparison of family physicians with and without rheumatology training during residency.

OBJECTIVE: To assess the long-term effect of an extensive rheumatology curriculum on graduates of family practice residencies. DESIGN: Cohort analytic study using a mailed survey and a multiple-choice test based on clinical vignettes that were administered 3 to 7 years after graduation from residency training. PARTICIPANTS: Practicing family physicians who had graduated from a community hospital family practice residency with an extensive rheumatology curriculum (trained) were compared with graduates from a similar program without specific rheumatology training (untrained). MAIN OUTCOME MEASURES: Total test scores, results of individual test questions, practice style, and attitudes toward rheumatology training and practice. RESULTS: We received 39 (85%) responses from 46 potential respondents in the trained group and 25 (89%) responses from 28 potential respondents in the untrained group. Physicians in the two groups had similar backgrounds and practice styles. The trained physicians scored higher on the multiple-choice test (mean +/- SD, 25 +/- 5 vs 22 +/- 6; P < .03). The clinical significance of these differences is a matter of individual interpretation. One hundred percent of the trained physicians believed that the quality of their rheumatology training was good to excellent compared with 25% of the untrained physicians. Seventy-six percent of the untrained physicians wished that they knew more about rheumatology. No variables other than rheumatology training accounted for the differences between the two groups. CONCLUSIONS: The difference in rheumatology knowledge, evident during and soon after residency between trained and untrained physicians, persists for 3 to 7 years.

Adult↗
PubMed1994

Recombinant human erythropoietin for the treatment of the anaemia associated with autologous bone marrow transplantation.

Patients with solid tumours undergoing high-dose chemotherapy with autologous bone marrow transplantation use an average of 10 units of packed red blood cells (PRBC) while awaiting haemopoietic reconstitution. They are also known to have inappropriately low endogenous erythropoietin levels for their degree of anaemia. This pilot study was designed to determine the effects of recombinant human erythropoietin (rHuEPO) on erythroid recovery and PRBC transfusion requirements. Ten patients received high-dose chemotherapy (days -7 to -3), bone marrow reinfusion (day 0), and then rHuEPO (day 1 onward). RHuEPO (200 units/kg intravenous bolus daily), along with iron supplementation, was administered for 28 d or until a haematocrit (Hct) of 35% (independent of transfusions) was reached, whichever occurred first. PRBCs were routinely given for Hct < or = 25% and platelets for counts < 20,000/microliters. Eight (80%) patients developed a brisk reticulocytosis (median peak reticulocyte count 0.32 x 10(9)/l) and a haematocrit > or = 30% independent of red blood cell transfusions within 32 d of receiving marrow, as compared to 20/37 (54%) similarly treated controls. An unexpected finding was the more rapid engraftment in myeloid and platelet lineages in a subset of rHuEPO-treated patients. Quick return of red blood cells (17 v 33 d) (P = 0.0001), platelets (14 v 19 d) (P = 0.04), and neutrophils (13 v 25 d) (P = 0.01) (with circulating myeloblasts and early myeloid forms) characterized recovery from an ifosfamide-based intensification with rHuEPO support. Similar trilineage enhancement of haemopoiesis did not occur with the possibly more myeloablative cyclophosphamide-based regimens. Despite the enhancement by rHuEPO on reticulocytosis, there was no significant decrease in PRBC transfusion requirements. RHuEPO proved to be a well-tolerated agent in enhancing reticulocytosis following high-dose chemotherapy. Further study to elucidate the activity of erythropoietin on both erythroid and non-erythroid growth and maturation appears warranted.

Adult↗
PubMed1994

Origins of hyperphenylalaninemia in Israel.

Mutations and polymorphisms at the phenylalanine hydroxylase (PAH) gene were used to study the genetic diversity of the Jewish and Palestinian Arab populations in Israel. PAH mutations are responsible for a large variety of hyperphenylalaninemias (HPAs), ranging from the autosomal recessive disease phenylketonuria to various degrees of nonclinical HPA. Seventy-two Jewish and 36 Palestinian Arab families with various HPAs, containing 115 affected genotypes, were studied by haplotype analysis, screening for previously known PAH lesions and a search for novel mutations. Forty-one PAH haplotypes were observed in this sample. Four mutations previously identified in Europe (IVS10nt546, R261Q, R408W and R158Q) were found, and were associated with the same haplotypes as in Europe, indicating possible gene flow from European populations into the Jewish and Palestinian gene pools. Of particular interest is a PAH allele with the IVS10nt546 mutation and haplotype 6, that might have originated in Italy more than 3,000 years ago and spread during the expansion of the Roman Empire. These results, together with previous identification of three PAH mutations unique to Palestinian Arabs [IVSnt2, Edel(197-205) and R270S], indicate that the relatively high genetic diversity of the Jewish and Palestinian populations reflects, in addition to genetic events unique to these communities, some gene flow from neighboring and conquering populations.

Amino Acid Metabolism, Inborn Errors↗
PubMed1994

Double dose-intensive chemotherapy with autologous marrow and peripheral-blood progenitor-cell support for metastatic breast cancer: a feasibility study.

PURPOSE: Twenty-seven percent of responding metastatic breast cancer patients remain progression-free a median 29 months following one intensification course of cyclophosphamide (6,000 mg/m2), thiotepa (500 mg/m2), and carboplatin (800 mg/m2) (CTCb) with autologous bone marrow transplantation (ABMT). European investigators report high complete response (CR) rates with melphalan for breast cancer. This trial studied the feasibility of two tandem high-dose intensification therapies in an attempt to optimize disease response and duration. PATIENTS AND METHODS: Women with at least partial responses (PRs) to induction therapy received melphalan (140 to 180 mg/m2), followed 24 hours later by chemotherapy and granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral-blood progenitor cells (PBPCs) and subsequent G-CSF until WBC recovery. The women were monitored as outpatients. After recovery, patients were hospitalized for CTCb with marrow, PBPC, and G-CSF support. RESULTS: Twenty women were assessable. Fourteen (70%) required admission for fever (10% infection) or mucositis (35%) after melphalan (median stay, 5 days). Median days of absolute neutrophil count (ANC) less than 500/microL and platelet count less than 20,000/microL were 6 and 5.5, respectively. Patients received CTCb 25 days after starting melphalan and had a hospital stay of 25 days. After CTCb, median days of ANC less than 500/microL and platelet count less than 20,000/microL were 11.5 and 24, respectively. Grade 3 toxicities included venoocclusive disease (VOD) (10%), mucositis (45%), and infection (20%). Toxicities were reversible without mortality. CONCLUSION: With mobilized PBPCs and growth factors, double dose-intensive chemotherapy is feasible with acceptable toxicity. When compared with trials using marrow alone, these supportive adjuncts decrease sepsis and organ toxicity. The concepts of dose and dose-intensity may now be more effectively and safely studied in chemosensitive tumors, including breast cancer.

Adult↗
PubMed1994

High-dose cyclophosphamide, thiotepa, and carboplatin with autologous marrow support in women with measurable advanced breast cancer responding to standard-dose therapy: analysis by age.

The analysis was undertaken to determine if the time to progression and survival for women with breast cancer treated with high-dose chemotherapy after a conventional-dose induction therapy differs significantly for women younger and older than 40 years of age. All patients treated in phase II or III protocols of high-dose chemotherapy for breast cancer are included in this analysis. Women were treated on one of six protocols: four sequential phase II protocols for metastatic breast cancer involving cyclophosphamide at a dose of 6000 mg/m2, thiotepa at 500 mg/m2, and carboplatin at 800 mg/m2 (CTCb) chemotherapy; one phase II study of CTCb chemotherapy for stage III or inflammatory breast cancer; and a Cancer and Leukemia Group B phase III study of cyclophosphamide, carmustine, and cisplatin for women with more than 10 involved lymph nodes after primary therapy. Eligibility criteria for the patients with metastatic disease included histologically documented breast cancer, at least a partial response to conventional dose therapy, no prior pelvic radiotherapy, cumulative doxorubicin of less than 500 mg/m2, and physiologic age of 18-55 years. Patients with inadequate renal, hepatic, pulmonary, and cardiac function or tumor involvement of marrow or central nervous system were excluded. Of 99 registered patients, three (3%) died of toxicity. There were no toxic deaths in protocols for stage II and III disease, and to date none of these patients have relapsed. Thus, there are no differences by age for these studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Chloral hydrate: a dangerous sedative for overdose patients?

A child ingested a stimulant and was sedated with chloral hydrate for agitation. An arrhythmia occurred following the chloral hydrate sedation. Chloral hydrate may be contraindicated when sedating children with stimulant ingestions.

Akathisia, Drug-Induced↗
PubMed1994

High-dose ifosfamide/carboplatin/etoposide with autologous hematopoietic stem cell support: safety and future directions.

Agents with broad cytotoxic activity, steep linear log dose-response relationships, relative non-cross-resistance, and nonoverlapping nonhematologic toxicities can be combined to create new high-dose combination regimens. We have previously reported phase I dose-escalation studies of ifosfamide, carboplatin, and the combination of the two. Etoposide has reported synergism with these alkylators and produces mucositis as its dose-limiting toxicity. The current study was designed to define the maximum tolerated doses of high-dose combination ifosfamide/carboplatin/etoposide (ICE), with stem cell support for amelioration of hematologic toxicity. Forty-eight adults with advanced malignancy received ICE chemotherapy by 96-hour continuous infusion. Initially, etoposide was added to fixed-dose ifosfamide and carboplatin, then the maximum tolerated dose of etoposide was fixed while doses of the alkylators were individually escalated. Autologous marrow, with or without peripheral blood progenitor cells, was reinfused 3 days after completing chemotherapy. The maximum tolerated doses of ifosfamide, carboplatin, and etoposide were identified as 16 g/m2, 1.8 g/m2, and 1.2 g/m2, respectively. Mortality was 4%. Patients who had prior cisplatin exposure were at increased risk for renal toxicity. If serum creatinine levels (monitored twice daily) rose sharply during chemotherapy, ifosfamide and carboplatin were immediately stopped. Severe multiorgan toxicity developed in the few patients who experienced early renal toxicity. Early stopping enhanced the safety of this regimen. Interpatient differences in chemotherapy drug metabolism or reduced renal clearance may predispose individuals to severe toxicity by increasing overall drug exposure. It was concluded that the ICE regimen is well tolerated and warrants further exploration as treatment of patients with small cell lung cancer, ovarian and germ cell carcinomas, and lymphomas in phase II trials.

Adult↗
PubMed1994

Basal cortisol levels and cognitive deficits in human aging.

A group of 19 healthy elderly subjects previously shown to differ in terms of their cortisol levels over a 4 year period were administered a neuropsychological test battery assessing memory, attention, and language. Correlational analyses performed on various corticosteroid measures showed that the slope of the change in cortisol levels over time predicted cognitive deficits in this elderly population. Aged subjects showing a significant increase in cortisol levels with years and with high current basal cortisol levels were impaired on tasks measuring explicit memory and selective attention when compared to aged subjects presenting either decreasing cortisol levels with years or increasing cortisol levels with moderate current basal cortisol levels. We further showed that subjects presenting a decrease in cortisol levels with years performed as well as young healthy subjects with regard to cognitive performance. Thus, impaired cognitive performance was associated with recent evidence of hypothalamic-pituitary-adrenal (HPA) dysregulation and elevated basal cortisol levels. These results are consistent with recent animal studies showing the existence of subpopulations of aged rats that differ in HPA activity and cognitive performance. Finally, the pattern of cognitive results related to the cortisol history of subjects is in agreement with a role played by the hippocampus in age-related HPA dysfunction and cognitive performance.

Aged↗
PubMed1993

Intensive combined modality therapy for limited-stage small-cell lung cancer.

BACKGROUND: Conventional-dose chemotherapy for small-cell lung cancer has resulted in high response rates but rarely in a cure. The addition of thoracic radiotherapy (chemoradiotherapy) has improved survival for patients having limited disease, resulting in a median survival of 14-18 months. Previous trials evaluating high-dose chemotherapy and autologous bone marrow transplantation have demonstrated enhanced complete response rates without documenting overall survival benefit. PURPOSE: The purpose of this phase II trial was to determine the disease-free and overall survival, toxic effects, and relapse patterns in patients with limited small-cell lung cancer who were in partial or complete response to first-line conventional-dose chemotherapy and then received intensive systemic combined modality therapy. METHODS: Adults with stage III small-cell lung cancer who had achieved at least a partial response to conventional-dose induction chemotherapy were treated with high-dose cyclophosphamide, cisplatin, and carmustine combined with autologous bone marrow transplantation. Cumulative doses of the three drugs were 5625, 165, and 480 mg/m2, respectively. After recovery, patients received thoracic radiotherapy (50-60 Gy in 25-30 fractions over 5-6 weeks) and cranial radiotherapy (30 Gy in 15 fractions during 3 weeks). RESULTS: Of 19 patients in the study, six had achieved complete response, eight had a greater than 90% reduction in tumor size, and five had a 50%-90% reduction in tumor size. After high-dose therapy, 15 of the 19 were in complete response. Overall, median time to treatment failure after high-dose therapy was 12 months. Overall survival was 73% (95% confidence interval [CI] = 42%-89%) at 1 year and 53% (95% CI = 22%-77%) at 2 years. Of the 14 patients in or near complete response before high-dose therapy, 10 remain disease free with no further chemotherapy a median of 15 (4-69+) months after therapy. Actuarial 2-year disease-free survival is 57% (95% CI = 20%-82%). One patient died of Candida sepsis. Morbidity was low, and most patients returned to full-time work. With the exception of herpes zoster, there were no complications more than 3 months after high-dose therapy. CONCLUSIONS: The majority of the patients in this study are experiencing prolonged and unmaintained disease-free survival. Our findings suggest that patients in or near complete response before high-dose therapy have the most favorable prognosis. IMPLICATIONS: A randomized comparison between this approach and conventional-dose therapy is planned to define the utility of dose intensification with autologous bone marrow transplantation in the treatment of patients with limited-stage small-cell lung cancer who are in or near complete response.

Actuarial Analysis↗
PubMed1993

Pre-operative combined 5-FU, low dose leucovorin, and sequential radiation therapy for unresectable rectal cancer.

PURPOSE: We performed a Phase I trial to determine the maximum tolerated dose of combined pre-operative radiation (5040 cGy) and 2 cycles (bolus daily x 5) of 5-FU and low dose LV (20 mg/m2), followed by surgery and 10 cycles of post-operative LV/5-FU in patients with unresectable primary or recurrent rectal cancer. METHODS AND MATERIALS: Twelve patients were entered. The initial dose of 5-FU was 325 mg/m2. 5-FU was to be escalated while the LV remained constant at 20 mg/m2. Chemotherapy began on day 1 and radiation on day 8. The post-operative chemotherapy, was not dose escalated; 5-FU: 425 mg/m2 and LV: 20 mg/m2. The median follow-up was 14 months (7-16 months). RESULTS: Following pre-operative therapy, the resectability rate with negative margins was 91% and the pathologic complete response rate was 9%. For the combined modality segment (preoperative) the incidence of any grade 3+ toxicity was diarrhea: 17%, dysuria: 8%, mucositis: 8%, and erythema: 8%. The median nadir counts were WBC: 3.1, HGB: 8.8, and PLT: 153,000. The maximum tolerated dose of 5-FU for pre-operative combined LV/5-FU/RT was 325 mg/m2 with no escalation possible. Therefore, the recommended dose was less than 325 mg/m2. CONCLUSIONS: Since adequate doses of 5-FU to treat systemic disease could not be delivered until at least 3 months (cycle 3) following the start of therapy, we do not recommend that this 5-FU, low dose LV, and sequential radiation therapy regimen be used as presently designed. However, given the 91% resectability rate we remain encouraged with this approach.

Adult↗