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Biomedical subjects

R Baratz

Publications and source records attributed to R Baratz.

9 recordsLinked to original sources
PubMed1993

Dentin as a possible bio-epidemiological measure of exposure to mercury.

The subtle human health effects from prolonged exposure to small amounts of mercury vapor are unknown. It has been difficult to study possible effects of low-dose exposure for lack of a good measure of long-term exposure. Current methods which use blood, urine, hair, and nails reliably measure only recent exposures. Long-term exposure to lead has been measured using levels found in human dentin. The purpose of this study was to determine whether mercury also accumulates in dentin. In this study, dentin from 16 human teeth, all without dental amalgam restorations, was analyzed by thermal neutron activation analysis. The teeth were selected from people with and without dental mercury amalgam restorations elsewhere in their dentitions. Mercury was found in amounts up to 5.9 ppm. While the highest mercury level was from a sample from someone who had dental amalgam restorations elsewhere in their dentition, the second highest was from someone who had no amalgam restorations. Also, a sample which was not used for any statistical comparisons but which was analyzed because the tooth contained an amalgam restoration had one of the lowest levels of mercury. These results, while inconclusive due to a small sample size, suggest that inorganic mercury vapor is a relatively small contributor to the overall body burden of mercury.

Adolescent↗
PubMed1985

Phase I and II clinical and pharmacological study of 4-demethoxydaunorubicin (idarubicin) in adult patients with acute leukemia.

Fifty-two adults treated previously with either acute leukemia (43 patients) or blastic-phase chronic myelogenous leukemia (nine patients) received 4-demethoxydaunorubicin (20 to 45 mg/sq m) i.v. over 2 to 3 days. Three of the ten patients with acute lymphocytic leukemia achieved a complete remission (CR) lasting 5 to 7 weeks. Five of the 28 patients with acute nonlymphocytic leukemia achieved a CR lasting 5 to 80 weeks. All remissions were induced with one course of treatment with a median time to CR of 28 days (range, 22 to 40 days). None of the patients with blastic chronic myelogenous leukemia or secondary leukemia achieved a CR. The drug was well tolerated; mucositis (36%), nausea and vomiting (35%), and hepatic dysfunction (26%) were the most common side effects. Pharmacokinetic observations on five patients demonstrated multiphasic clearance of 4-demethoxydaunorubicin and extensive formation and prolonged retention of 4-demethoxy-13-hydroxydaunorubicin; that metabolite accumulated in plasma on repeated daily dosing. 4-Demethoxydaunorubicin has sufficient antileukemic activity in both acute lymphocytic leukemia and acute nonlymphocytic leukemia to warrant a prospective comparison, in combination regimens, against the conventional anthracyclines, daunorubicin and/or doxorubicin.

Acute Disease↗
PubMed1985

Phase I and clinical pharmacological evaluation of 4'-deoxydoxorubicin in patients with advanced cancer.

We have conducted a Phase I and initial clinical pharmacological evaluation of 4'-deoxydoxorubicin (4'-DXDX), administering the drug i.v. on an every 21-day schedule to 60 patients with advanced cancer. Patients were treated at six dosage levels ranging from 10 to 35 mg/sq m. Leukopenia was the dose-limiting toxic effect, and no cardiac, renal, or hepatic toxicity was observed; stomatitis was not seen; and there were no drug-related deaths. Significant alopecia was rare at doses less than 35 mg/sq m, mild nausea and vomiting occurred in one-third of patients at myelosuppressive doses; 12 patients had a transient local urticarial reaction. In the 30 patients with measurable disease, two partial remissions were seen, lasting 5 months in a patient with a nasopharyngeal adenocarcinoma, and 7 months in a patient with endometrial adenocarcinoma. The recommended dose of 4'-DXDX for Phase II studies is 30 mg/sq m in good-risk patients and 25 mg/sq m in moderate-risk or heavily pretreated patients. Pharmacokinetic studies were carried out in ten patients, four of whom received 4'-DXDX at a dose of 10 mg/sq m and six at 30 mg/sq m. Disappearance of 4'-DXDX from plasma was triphasic with a rapid initial phase clearance showing a t1/2 alpha of 1 to 2 min and a prolonged terminal phase with a median t1/2 gamma in excess of 90 h in patients receiving 30 mg/sq m.

Adult↗
PubMed1983

Phase I and clinical pharmacology studies of intravenous and oral administration of 4-demethoxydaunorubicin in patients with advanced cancer.

4-Demethoxydaunorubicin (4-DMDR), an anthracycline analogue available in i.v. and p.o. form, has shown significant antitumor activity in murine tumor models while producing less cardiac toxicity than doxorubicin at equimyelotoxic doses. Phase I and clinical pharmacology studies of the i.v. and p.o. preparation were performed. With i.v. 4-DMDR, consistent myelosuppression was observed at a dose of 15 mg/sq m at a median Day 15; mild nausea and vomiting were observed in 9% of all treatment courses. In patients given p.o. 4-DMDR, myelosuppression occurred at median Day 14 in 10 of 12 patients given 50 mg/sq m. Nausea and vomiting occurred in 25% of all treatment courses, and dividing the dose over 3 days did not decrease the incidence. Alopecia occurred in 13% of evaluable patients treated with the i.v. preparation and 30% of evaluable patients treated p.o. No stomatitis was observed with either preparation, and no patient developed clinical signs of congestive heart failure. Pharmacokinetic studies were performed with both preparations and revealed prolonged plasma levels of the 13-hydroxy metabolite 4-DMDR-ol. The suggested starting dose for Phase II studies is 12.5 mg/sq m given every 21 days for i.v. 4-DMDR with dose escalation by 2.5 mg/sq m in the absence of myelotoxicity. For p.o. 4-DMDR, the suggested starting dose is 40 mg/sq m given every 21 days with escalation by 10 mg/sq m if no myelotoxicity is observed.

Administration, Oral↗
PubMed1981

Adult-onset stuttering treated with anticonvulsants.

Stuttering and aphasia emerged as salient clinical features in an adult with multifocal brain damage and paroxysmal EEG activity. Anticonvulsant treatment was associated with reversal of the stuttering and with marked improvement in language abilities.

Adult↗