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Biomedical subjects

J Jin

Publications and source records attributed to J Jin.

At least 181 records · Page 10Linked to original sources
PubMed1993

[Studies on CD spectra of derivatives of shikonin and alkannin].

The circular dichroism (CD) and electronic absorption spectra of seven derivatives of shikonin and alkannin isolated from the roots of Onosma confertum W.W. Smith (from Sichuan) and Arnebia euchroma (Royle) Johust (from Xinjiang) were described. Each pair of CD spectra obtained was exact mirror images and the UV spectra of these compounds were very similar. In comparison with the CD spectra of shikonin given in literature, the configuration of the pigments from Sichuan was assigned R and from Xinjiang were all S.

Circular Dichroism↗
PubMed1993

A comparative study on the solid phase capture--platelet test, platelet adhesion immunofluorescence test and lymphocytotoxic test.

The sensitivity, specificity and reproducibility of the solid phase capture-platelet test (CPT) were compared with those of the platelet adhesion immunofluorescence test (PAIFT) and the lymphocytotoxic test (LCT). This study shows that CPT has a higher sensitivity than PAIFT (P < 0.001) and LCT (P < 0.01). The specificity was 86% lower than LCT (100%) (P < 0.01). Both the CPT test and PAIFT were comparable with regard to reproducibility (100%, 92%). The solid phase assay is easier to handle than PAIFT and LCT, allowing identification of HLA as well as of platelet specific antibodies. It is an efficient antibody screening test.

Antibody Specificity↗
PubMed1992

Light-dependent delay in the falling phase of the retinal rod photoresponse.

Using suction electrodes, photocurrent responses to 100-ms saturating flashes were recorded from isolated retinal rods of the larval-stage tiger salamander (Ambystoma tigrinum). The delay period (Tc) that preceded recovery of the dark current by a criterion amount (3 pA) was analyzed in relation to the flash intensity (If), and to the corresponding fractional bleach (R*0/Rtot) of the visual pigment; R*0/Rtot was compared with R*s/Rtot, the fractional bleach at which the peak level of activated transducin approaches saturation. Over an approximately 8 ln unit range of I(f) that included the predicted value of R*s/Rtot, Tc increased linearly with ln I(f). Within the linear range, the slope of the function yielded an apparent exponential time constant (tau c) of 1.7 +/- 0.2 s (mean +/- S.D.). Background light reduced the value of Tc measured at a given flash intensity but preserved a range over which Tc increased linearly with ln I(f); the linear-range slope was similar to that measured in the absence of background light. The intensity dependence of Tc resembles that of a delay (Td) seen in light-scattering experiments on bovine retinas, which describes the period of essentially complete activation of transducin following a bright flash; the slope of the function relating Td and ln flash intensity is thought to reflect the lifetime of photoactivated visual pigment (R*) (Pepperberg et al., 1988; Kahlert et al., 1990). The present data suggest that the electrophysiological delay has a similar basis in the deactivation kinetics of R*, and that tau c represents TR*, the lifetime of R* in the phototransduction process. The results furthermore suggest a preservation of the "dark-adapted" value of TR* within the investigated range of background intensity.

Ambystoma↗
PubMed1992

[The effect of 211At labelled monoclonal antibody against gastric cancer on DNA, RNA and protein synthesis in gastric cancer cell].

By means of nuclide precursor incorporation, the effects of 211At labelled monoclonal antibody against gastric cancer (211At-3H11McAb) on DNA, RNA and protein synthesis in gastric cancer cell were studied. The results show that 211At-3H11McAb and Na211At-3 inhibit 3H-TdR, 3H-UR and 3H-Leu incorporation, especially 3H-UR incorporation, into gastric cancer cell at 3.7 x 10(4)Bq and 1.85 x 10(5)Bq; the inhibiting rates depend on concentration. The DNA biosynthesis in gastric cancer cell gradually recover after the drug is removed, suggesting that the drug should exert an inhibiting action on DNA biosynthesis in tumor cell through interference of DNA metabolism.

Antibodies, Monoclonal↗
PubMed1991

New posture equilibrometer for the diagnosis of vestibular disease.

The vestibulospinal level of vestibular function is commonly neglected in the evaluation of vertiginous patients. We have now developed a new posture equilibrometer. A transducer is placed on the head of the subject being tested. With this meter we can record body swaying, X (left-right) and Y (fore-aft) components of angular displacement, angular velocity, and angular acceleration. A detailed analysis of the data can be made by having patients keep their eyes either open or closed during the Romberg test. The head is turned left or right in this test, while the eyes are opened and closed in the Mann test. The posture equilibrometer has enabled us to evaluate more precisely vestibulospinal function and sensory interactions.

Adolescent↗
PubMed1990

Sensitization of bleached rod photoreceptors by 11-cis-locked analogues of retinal.

Photoactivation of rhodopsin initiates both excitation and adaptation in vertebrate rod photoreceptors. Bleaching of rhodopsin to free opsin and all-trans-retinal in isolated rods produces a stable desensitization (bleaching adaptation) that is much larger than expected from pigment depletion alone. In our experiments, a 93% bleach produced a 500-fold increase in the light intensity required for saturation of the light response. This component of adaptation was 32-fold larger than the 16-fold increase expected from pigment depletion alone. 11-cis-Retinal, when delivered to isolated rods from liposomes, combines with free opsin to form a bleachable photopigment that fully restores sensitivity. 11-cis-Locked analogues of retinal combine with opsin to form unbleachable pigments in isolated bleached rods from the tiger salamander. They restore sensitivity to a substantial (16- to 25-fold) but incomplete extent. The analogues apparently relieve a stable component of adaptation when they interact with opsin. Because these analogues do not detectably excite rods, the structural requirements of both retinal and opsin for the relief of adaptation are different from those of excitation. The biochemical basis of light adaptation resulting from pigment bleaching and the minimum structural requirements of retinal for its relief remain to be determined.

Ambystoma↗
PubMed1989

A posture equilibrometer for the diagnosis of vestibular disease.

Since the vestibulospinal level of vestibular function is frequently neglected in the evaluation of vertiginous patients, we developed a new posture equilibrometer for recording body swaying X (left-right) and Y (fore-aft) components of angular displacement, velocity, and acceleration with its transducer on the head of the subject. The data from patients undergoing Romberg test with eyes open and closed, Romberg test with head turned left and right and Mann test were analysed. We conclude that the equilibrometry allows one to evaluate precisely the vestibulospinal function and the sensory interaction.

Adolescent↗
PubMed1989

[Synthesis of antiviral agents acyclic nucleo-sides of 4-substituted pyrrolo [2,3-d] pyrimidine].

Naturally occurring nucleosides of pyrrolo [2,3-d] pyrimidine, tubercidin, sangivamycin and toyocamycin were known as antibodies not only for their potent antitumor activity but also for their significant antiviral effects. However, none of them was developed to be a useful drug due to their high toxicity. In order to reduce the toxicity of this kind of compounds and reveal the relationship between structure and biological activity, a series of acyclic analogues of tubercidin with varied 4-substituted amino groups were synthesized. 4-chlor-pyrrolo (2,3-d) pyrimidin was used as starting material which reacted with 1,3-dibenzyloxy-glycerol-2-chloro-methylether by direct sodium salt glycosylation procedure provided the key intermediate (IX). After hydrogenation, amination of compound IX gave the final free hydroxy products. All the compounds were tested in vitro against HSV-1 and Cox B6. Only three of them (XI6, XI7, XI9) showed certain activities against Cox B6.

Aminoglycosides↗
PubMed1988

Studies on fermented corn flour food poisoning in rural areas of China. II. Isolation and identification of causal microorganisms.

Using potato dextrose agar medium, 40 strains of microorganisms were isolated from leftover fermented corn flour samples involved in outbreaks of food poisoning. All strains produced powerful toxins which caused the same intoxication to mice, dogs, and monkeys as the leftover food samples. On the basis of results obtained from the morphology of this bacteria and its colony, from biochemical tests, and from the G-C mole percentage in DNA, the bacteria was identified as Flavobacterium farinofermentans nov. sp. (Meng, Z. and Wang, D.).

Agglutination Tests↗
PubMed1988

Studies on fermented corn flour poisoning in rural areas of China. I. Epidemiology, Clinical Manifestations, and Pathology.

An outbreak of a new type of fatal food poisoning has been reported in different parts of the People's Republic of China. Liver, kidney, heart, and brain were the main target organs, and the overall fatality of intoxicated individuals was 38.2%. Evidence obtained from epidemiological studies and animal tests indicates that the food poisoning was caused by the consumption of homemade fermented corn flour products.

Animals↗
PubMed1975

Effect of althesin (CT-1341) on thyroid-adrenal function in man.

The effects of althesin on adrenocortical and thyroid function were investigated by measuring plasma concentrations of cortisol, thyroxine (T4) and free thyroxine index (FTI) in 29 surgical patients. Althesin did not change the plasma cortisol concentrations from the preanaesthetic control value; however, the concentrations increased significantly after the start of surgery and thereafter. Althesin anaesthesia per se decreased slightly, but significantly, plasma T4 concentration, but did not influence the FTI value. The surgical operation increased the FTI value slightly but significantly. Our data would suggest that Althesin anaesthesia can be used in patients who have abnormal adrenocortical or thyroid activity.

Adolescent↗
PubMedDate not supplied

Movement of retinal along cone and rod photoreceptors.

Single isolated photoreceptors can be taken through a visual cycle of light adaptation by bleaching visual pigment, followed by dark adaptation when supplied with 11-cis retinal. Light adaptation after bleaching is manifested by faster response kinetics and a permanent reduction in sensitivity to light flashes, presumed to be due to the presence of bleached visual pigment. The recovery of flash sensitivity during dark adaptation is assumed to be due to regeneration of visual pigment to pre-bleach levels. In previous work, the outer segments of bleached, light-adapted cells were exposed to 11-cis retinal. In the present work, the cell bodies of bleached photoreceptors were exposed. We report a marked difference between rods and cones. Bleached cones recover sensitivity when their cell bodies are exposed to 11-cis retinal. Bleached rods do not. These results imply that retinal can move freely along the cone photoreceptor, but retinal either is not taken up by the rod cell body or retinal cannot move from the rod cell body to the rod outer segment. The free transfer of retinal along cone but not along rod photoreceptors could explain why, during dark adaptation in the retina, cones have access to a store of 11-cis retinal which is not available to rods. Additional experiments investigated the movement of retinal along bleached rod outer segments. The results indicate that retinal can move along the rod outer segment, but that this movement is slow, occurring at about the same rate as the regeneration of visual pigment.

Ambystoma↗