Biomedical subjects

T T Than

Publications and source records attributed to T T Than.

4 recordsLinked to original sources

PubMed1994

Sucrose threshold variation during the menstrual cycle.

Sucrose thresholds were measured at three points during the menstrual cycle for 14 women who were not taking oral contraceptives. Thirteen men also were tested at similar intervals. Sucrose thresholds of the men remained constant throughout the experiment. During menstruation and postovulation, the thresholds of the women were similar to the thresholds of the men, whereas during preovulation the thresholds of the women are significantly lower. The stable sucrose thresholds of the men suggest that ovarian hormones may be involved in the variation in sucrose sucrose thresholds of the women. The increase in sensitivity of the women during preovulation may have been related to the high level of estrogen, whereas the decrease in sensitivity during postovulation may be due to some type of interaction between estrogen and progesterone.

Adolescent↗

PubMed1992

Intrathecal 4-hydroperoxycyclophosphamide: neurotoxicity, cerebrospinal fluid pharmacokinetics, and antitumor activity in a rabbit model of VX2 leptomeningeal carcinomatosis.

Dissemination of tumor to the leptomeninges and cerebrospinal fluid represents a common pattern of metastasis for many cancers; however, few chemotherapeutic agents are available for intrathecal (i.t.) use and treatment results are often poor. We studied the neurotoxicity and pharmacokinetics of i.t. 4-hydroperoxycyclophosphamide (4-HC) in the rabbit and the activity of i.t. 4-HC in a VX2 rabbit model of leptomeningeal carcinomatosis to evaluate the potential use of 4-HC in the treatment of leptomeningeal tumors. Toxicity studies examined 4-HC doses ranging from 0.5 to 6.0 mumol administered by intraventricular injection weekly for 4 to 8 weeks. Clinical or histological neurotoxicity was not observed in rabbits treated with < 1.0 mumol 4-HC for 4 weeks. Clinical toxicity, characterized by lethargy, weight loss, seizures, or death, was apparent at doses > 2.0 mumol. Vasculitis of superficial arteries was observed in rabbits treated with > 1.0 mumol 4-HC. In cerebrospinal fluid pharmacokinetic studies, the mean drug half-life after intraventricular or intralumbar administration was 24.3 and 18.2 min. Regional inequities in drug exposure were apparent as area under the clearance curve values for cerebrospinal fluid distant from the injection site were lower than those of proximate sites (P < 0.001). Weekly intraventricular treatment of VX2 leptomeningeal tumor-bearing rabbits with 0.5 or 1.0 mumol of 4-HC resulted in an increased life span of 22.5 and 35%, respectively. These results indicate that i.t. 4-HC, at doses lower than those producing neurotoxicity in the rabbit, is effective treatment for VX2 leptomeningeal carcinomatosis.

Animals↗

PubMed1990

[Pediatric anesthesia and pharmacokinetics of propofol administered at a constant rate].

The pharmacokinetic properties of propofol given at a constant rate, were studied in 10 children. Propofol was administered at a dose according to I.C.I. Pharma advices. For minor surgery, a low quality of general anesthesia was observed in correlation with low plasma levels of propofol. An increase in dosage would be necessary in children above 8 years old.

Adolescent↗

PubMed1989

A method for hepatic arterial perfusion studies in the rat.

The current model for selective hepatic arterial infusion therapy was evaluated for its suitability for short-term pharmacokinetic experiments. This preparation consists of selective cannulation of the common hepatic artery via the gastroduodenal artery of the rat. Radioactive microspheres were injected to determine hepatic or extrahepatic sites of perfusion. Radioactive microsphere determination of hepatic arterial flow and cardiac output were also performed. Our data indicate that at high flow rates (2 ml/min), significant loss of drug would occur due to retrograde flow. Modification of the model to include temporary proximal hepatic artery occlusion ensures hepatic delivery of greater than 95% of drug. Furthermore, temporary hepatic artery occlusion does not alter cardiac output or hepatic arterial blood flow. Selective hepatic arterial infusion in rats with synchronous temporary hepatic artery occlusion is an adequate model for short-term pharmacokinetic studies.

Animals↗