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Biomedical subjects

A Li

Publications and source records attributed to A Li.

At least 307 records · Page 17Linked to original sources
PubMed1992

Homozygous pyruvate kinase deficiency in Hong Kong ethnic minorities.

Three cases of pyruvate kinase (PK) deficiency resulting in congenital haemolytic anaemia with transfusion dependency are described. These cases resulted from consanguineous marriages in non-Han Chinese and include a pair of twins. We believe this to be the first documentation of homozygous PK deficiency in the Hong Kong population. The diagnosis was masked due to transfusion dependency in each case stressing the need to take a sample of pretransfusion blood for PK enzyme assay, and for family studies, when this disorder is suspected.

Anemia, Hemolytic↗
PubMed1992

Answering MCQs: a study of confidence amongst medical students.

Medical students at the beginning of their obstetrics and gynaecology module were asked to complete a multiple choice question paper from an earlier module. Half the students were asked to answer only those questions where they were certain of the answers. The other half were asked to answer all questions. The mean mark in the second group was 86% higher than that in the first group. A computer programme was written where multiple choice questions were asked in a standard true/false format but instead of a don't know alternative the students were asked to rate their degree of certainty in having answered correctly on a scale of 0 to 100. Five students completed a total of 45 multiple choice question papers (each with 20, 5-part questions) both before and towards the end of their obstetrics and gynaecology module. The mean mark increased by 68.5% over the course of the module reflecting the students' increased knowledge. Their mean certainty level only increased by 50%, suggesting that the students underestimated their newly acquired knowledge.

Educational Measurement↗
PubMed1992

Retrofacial lesions: effects on CO2-sensitive phrenic and sympathetic nerve activity.

We made unilateral chemical (10- or 50-nl microinjections; 4.7 mM kainic acid) or electrolytic (5-15 mA; 15 s) lesions in a region of the rostral ventrolateral medulla (VLM) caudal to the retrotrapezoid nucleus in 10 decerebrate, paralyzed, vagotomized, and servo-ventilated cats. The lesions were 3.0-4.2 mm lateral to the midline, within 2 mm caudal to the facial nucleus, and within 2.5 mm of the VLM surface. Four control injections (mock cerebrospinal fluid and fluorescent beads alone) produced small and inconsistent effects over 3-5 h. The predominant effect of the lesions was a significant decrease in baseline integrated phrenic nerve amplitude (PNA) (apnea in 2 cases), total respiratory cycle duration, and the response to increased CO2 (slope < 15% of control in 3 cases). The respiratory-related peak amplitude of the integrated sympathetic signal, blood pressure, and the sympathetic nerve activity response to CO2 were also decreased after the majority of lesions. Not all lesions produced all effects, and some lesions resulted in increased PNA and respiratory cycle duration. The lesioned region appears functionally to represent a caudal extension of the retrotrapezoid nucleus containing neurons necessary for normal baseline PNA and CO2 sensitivity. In addition, it contains neurons involved in the determination of resting respiratory frequency and normal sympathetic activity and blood pressure. The pattern of mixed responses among animals suggests that a heterogeneity of function is present within a relatively small VLM region.

Animals↗
PubMed1992

[Isolation of HAV from sea clam].

Three strains of HAV were isolated directly from clams (Arca Subcrensta Lisckke) collected from sea with cell culture and identified by electron microscopy, immunofluorescent test, ELISA, HAV-cDNA hybridization and neutralization test. The strains were stably passed in 2BS cells with the titer of 4.0-5.0 TCID50/ml. Results indicated that the clams were contaminated by HAV and may cause an outbreak of hepatitis A.

Animals↗
PubMed1992

[An urease negative Cryptococcus neoformans].

We report an urease negative Cryptococcus neoformans derived from pigeon dropping. This isolate produced brown pigmented colonies on cornmeal Tween-80 agar with 300 micrograms/ml caffeic acid, but was failure to hydrolyze urea. More identification tests were performed for this isolate, such as assimilation and fermentation of carbohydrates, nitrate assimilation, production of starch like compound, growth on GCP medium, germ tube formation and inoculation of mice, ect. Most of the results showed that the microbiological characteristics of the isolate were typical of C. neoformans except for negative urease test. Even though there has been a report about an urease negative C. neoformans derived from an AIDS patient, but we have never found any report about isolation from pigeon dropping or nature environment. We should pay attention to the exist of this atypical strain of C. neoformans in nature environment and the possibility of infection to human being. Additionally, we also be aware of the possibility of neglect when this urease negative C. neoformans is identified with urease test.

Animals↗
PubMed1992

[Farm irrigation index for culturing Panax ginseng C.A. Meyer].

The growth and yield of annual and perennial Panax ginseng were observed by applying methods of mini-irrigation and irrigation under different negative pressures of soil humidometer. After four experiments optimum values of negative pressure were found to assist timely irrigation, thus providing scientific criteria of rational irrigation and automated mini-irrigation for culturing Panax ginseng.

Humidity↗
PubMed1991

Sulfation and glucuronidation of acetaminophen by cultured hepatocytes reproducing in vivo sex-differences in conjugation on Matrigel and type 1 collagen.

The sulfate and glucuronide conjugation of acetaminophen (APAP) by hepatocytes cultured on Matrigel or type 1 collagen was compared to APAP metabolism in vivo. The metabolic fate of low (15 mg/kg), medium (125 mg/kg), and high (300 mg/kg) doses of APAP injected intraperitoneally were determined in male and female rats. Males excreted more APAP as the sulfate conjugate than females, which correlated with the twofold greater APAP sulfotransferase activity in the male vs. females (301 +/- 24 vs. 156 +/- 18 pmol.mg-1 protein.min-1). Also, as sulfate conjugation became saturated, there was a dose-related shift in APAP metabolism from sulfate to glucuronide conjugation in both sexes. After death, the livers of the same animals were perfused with collagenase and the hepatocytes cultured in modified Waymouth's medium on either Matrigel or rat-tail collagen, with various doses of APAP (0, 0.125, 0.25, 0.5, and 1.0 mM). Sex differences in APAP sulfation and glucuronidation persisted in culture for up to 4 days, with sulfation predominating in the male similar to in vivo. With increasing APAP concentration (dose), there was a saturation of sulfate conjugation and a shift to glucuronidation as observed in vivo. Sex differences in APAP sulfation and glucuronidation were no longer significant by Day 4 in culture. Sulfation, and to a lesser extent, glucuronidation, were more stable on Matrigel than collagen. We concluded that APAP metabolism of freshly isolated hepatocytes could replicate in vivo sex differences in conjugation, and that Matrigel was superior to collagen as substrate.

Acetaminophen↗
PubMed1991

Further explorations of abnormalities in serum proteins following burns.

This report extends our earlier studies of the abnormal protein bands found in burn sera by use of Western blotting and ion exchange chromatography. The current studies indicated that some of the protein bands contained materials with immunosuppressive activity. One of these materials cross reacted with anti human haptoglobin antibody. Many of the other proteins in the bands were found to be acute phase reactant proteins without immunosuppressive activity. Some proteins in these bands have not yet been characterized or tested for immunosuppressive activity.

Adult↗
PubMed1991

Application of sulcated half-ring external fixator for treating bone and joint injuries of burned lower extremities: a report of four cases.

Four patients with burned lower extremities complicated with severe bone and joint injuries were treated with sulcated half-ring external fixators. The results were satisfactory. This apparatus is simple, easy to handle and effective. Using this fixator, the burn wounds as well as the bone and joint injuries could be managed at the same time, without mutual interference. As it seems a desirable method for the management of such compound injuries, the advantages and disadvantages of this apparatus are discussed.

Adult↗
PubMed1991

Regeneration of transgenic Lycium barbarum L.

A simple and effective system for the transformation and regeneration of Lycium barbarum L. has been developed. Young stem segments from Lycium barbarum L. were infected by Agrobacterium tumefaciens harboring a vector containing neomycin phosphotransferase II (npt-II) gene derived from non-oncogenic Ti plasmid. Calli originating from young stem segments on selective induction medium could differentiate into buds on selective differentiation medium rapidly and finally developed into whole plants. NPT-II enzyme activity assay and DNA hybridization indicated that the foreign gene had been integrated into the genome of Lycium barbarum L. and could be expressed in plants.

Kanamycin↗
PubMed1991

Some monoclonal anti-human lymphocyte and class II MHC antigen antibodies do not stain snap frozen Macaca fascicularis lymphocytes or tissue sections.

Experiments were designed to stain snap frozen and fixed Macaca fascicularis peripheral blood mononuclear cell (PBMC) preparations and colon sections assuming that monoclonal mouse anti-human lymphocyte and class II major histocompatibility complex antigen antibodies would cross-react with the monkey counterparts to the human antigens. Most of the monoclonals used in this study did not stain the monkey frozen and fixed tissues in immunoenzymatic protocols despite adequate staining of control human tissues. The fact that snap frozen Macaca fascicularis PBMCs and tissue sections were not always stained is of practical importance for experimental design in Macaca fascicularis using anti-human reagents.

Animals↗
PubMed1991

[Effects of processing on toxicity and pharmacological action of Phytolacca americana L].

The experimental results have shown that the toxicity of variously processed Phytolacca americana is lower than that of the original rude drug, i.e. the local irritability tends to decrease by 16.7-83.3%; LD50 to elevate by 1.66-10.47 times; expectoration to increase by 1.10-1.57 times; but diuresis mostly to decrease by 16.0-45.0%. This reveals that the main object of processing Phytolacca americana is to lower toxicity, increase expectoration and relieve diuresis to reduce fluid retention.

Animals↗
PubMed1991

[Clinical observation of macular disease in patients with diabetic retinopathy].

The population was 65 cases (122 eyes) of diabetic macular disease. Background diabetic retinopathy was observed in 40 eyes, i.e., 32.80%. For the 82 eyes present proliferative diabetic retinopathy, i.e., 67.20%. According to Sigelmen's classification, 17 eyes were in stage I, i.e., 13.93% of the cases; 41 eyes were in stage II, i.e., 33.60% of the cases; 40 eyes were in stage III, i.e., 32.80% of the cases; 24 eyes were in stage IV, i.e., 19.67% of the cases. There were 122 eyes in this group. The visual acuity of 66 eyes showed > or = 0.3, i.e., 54.00%, while that of 56 eyes showed 40.3 i.e. 46.00%. Nearly half patients showed low visual acuity and loss of vision. This result was responsible for the cases who were at the late stage of diabetic and with a long history of diabetic or the diabetic was poorly controlled. So the writer appeal to ophthalmologists and physicians to prescribe the effective guides to all the diabetic patients. We suggest that it is important that dynamic observation be carried out of hemorhelological manifestation and early treatment diabetic retinopathy for the clinical prevention and treatment of diabetic retinopathy.

Adult↗
PubMed1991

Changes of length of elastic fibers in rabbit lungs after smoke inhalation injury.

Pulmonary morphometry was determined in rabbit lungs after smoke inhalation. Twenty-four hours after injury, changes of the total lung volume (TLV) and the total length of all parenchymal elastic fibers (LT) were measured. Concomitant changes in arterial blood gas levels and pathomorphology of lung tissues were also studied. It was found that alveolar walls were broken and became thinner, and that alveoli were dilated. TLV was markedly increased and LT was markedly decreased as compared to normal lungs (P less than 0.05). These findings suggest that proteinases, especially elastase, released from phagocytes may play an important role in acute lung injury after smoke inhalation.

Animals↗