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Biomedical subjects

L Lin

Publications and source records attributed to L Lin.

At least 379 records · Page 21Linked to original sources

Oxidation of 5-hydroxytryptamine and 5,7-dihydroxytryptamine. A new oxidation pathway and formation of a novel neurotoxin.

The electrochemical oxidation of 5-hydroxytryptamine (5-HT) in acidic solution proceeds through a minor route leading first to 5,7-dihydroxytryptamine (5,7-DHT) then to 4,5,7-trihydroxytryptamine and finally to 5-hydroxytryptamine-4,7-dione. The latter compound is a major electrochemical oxidation product of 5,7-DHT at pH 2 and 7 and a major autoxidation product at pH greater than or equal to 6. Preliminary biological results indicate that 5-hydroxytryptamine-4,7-dione is a more potent central nervous system toxin than 5,7-DHT. These results show for the first time a chemical pathway from 5-HT to 5,7-DHT and suggest possible minor metabolic oxidative pathways for the neurotransmitter 5-HT to at least two powerful neurotoxins.

5,6-Dihydroxytryptamine↗

Rapid automated high-performance liquid chromatographic analysis of cyclic adenosine 3',5'-monophosphate. Synthesis in brain tissues.

A rapid and sensitive automated system for measuring cyclic adenosine 3',5'-monophosphate (cAMP) synthesized from either radiolabelled adenine or adenosine 5'-triphosphate (ATP) in intact and broken cell tissue preparations, respectively, is described. After incubation with radiolabelled precursor, tissue samples are deproteinized and then injected directly onto a reversed-phase high-performance liquid chromatographic column. The column effluent fraction which contains cAMP is collected into scintillation vials and assayed for tritium by liquid scintillation spectrometry. Since the high-performance liquid chromatographic and fraction collection procedures are automated, over fifty samples can be analyzed in duplicate in a single day. The utility of this assay is illustrated by investigations of the effects of beta-adrenergic receptor stimulation on cAMP synthesis in tissue slices prepared from rat cerebral cortex and dopamine on cAMP synthesis in striatal membrane preparations.

Adenine↗

Evaluation of papain/chymopapain cross allergenicity.

Recent clinical evidence suggests that papain and chymopapain may share common allergenicity. Patients that become sensitized to papain may subsequently experience an allergic reaction when they are exposed to chymopapain. This study demonstrates a cross antigenicity between the proteolytic enzyme preparations papain and chymopapain. Serum samples from six patients who demonstrated 4+ skin reactions to papain also revealed positive RAST ratios to both papain and chymopapain. In addition, serum samples from 12 clinically nonreactive patients who had discolysis with chymopapain demonstrated positive RAST results to papain as well as to chymopapain.

Allergens↗

Early diagnosis of scoliosis based on school-screening.

A total of 8165 schoolchildren were screened for scoliosis by two teams of orthopaedic surgeons using the same procedures and criteria. Of 790 children who had positive physical signs, 689 were examined roentgenographically. Using 5 and 10 degrees as cut-off points, the prevalence of scoliosis was 6.58 and 2.4 per cent, respectively. A follow-up study of children who had been reported to have scoliosis at the age of eleven months showed that only half of them actually had scoliosis.

Adolescent↗

The introduction of postpartum intrauterine devices in the People's Republic of China.

In China, which has a commitment to family planning and, in particular, to the one-child family, a postpartum IUD should be widely accepted and could have significant impact on the Chinese family planning program. This report presents the introduction of the Delta T and Delta Loop devices, with 200 immediate postpartum insertions. Fifty-two deliveries were by cesarean section. The 6-month expulsion rates were 13.3 and 17.2 for the Delta T and Delta Loop, respectively. There was one pregnancy reported. Analysis suggests that the two devices are suitable for use in the postpartum period for Chinese women.

Adult↗