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Biomedical subjects

S R Lin

Publications and source records attributed to S R Lin.

At least 91 records · Page 5Linked to original sources
PubMed1993

[Study on urinary arsenic, lead and cadmium concentrations in a steel production workers].

Lead and cadmium levels in urine specimens were determined simultaneously by polarographic method, and arsenic by hydride atomic absorption spectrophotometry. The urine specimens were pretreated with a mixed acid solution and ORTHO bilevel urine metal control and APG Setpoint standard were used to check the analytical accuracy. The results showed the total arsenic [As], lead [Pb], cadmium [Cd] levels in the production and the quality control workers, were significantly higher than those in the control. The results indicate the need for an immediate improvement in workplace ventilation and industrial hygiene practices.

Arsenic↗
PubMed1993

Chemical modification of amino groups in cardiotoxin III from Taiwan cobra Naja naja atra) venom.

Cardiotoxin III (CTX III), a major cardiotoxin analogue isolated from the Taiwan cobra (Naja naja atra) venom was modified, either with trinitrobenzene sulfonate (TNBS) or 4-chloro-3,5-dinitrobenzoate (CDNB). Under the conditions of limited reagent availability, three mono-TNP derivatives modified at Lys-5, 12, or 44, and three mono-CDNP derivatives at Lys-12, 23, or 44 were isolated, respectively. The biological activities of CTX III were more or less affected after each of these reactive amino groups were modified. In particular, the hemolytic activity to human erythrocytes and cytotoxicity on NS-1 cells of CTX III decreased to 31% and 50%, respectively, when Lys-12 was trinitrophenylated. More pronounced alteration in these activities was observed as this amino group was carboxydinitrophenylated. A good correlation between the hemolytic activity and cytotoxicity was found. These results indicate that epsilon-amino group at Lys-12 is most closely related to the hemolytic and cytotoxic activities of CTX III. The antigenicity of modified derivatives still remained intact as measured by ELISA.

Animals↗
PubMed1993

Characterization of genetic defects of hemophilia A in patients of Chinese origin.

The molecular characterization of hemophilia A of Chinese origin was carried out by the polymerase chain reaction (PCR) and direct sequencing of patients' factor VIII genes. Single-strand conformation polymorphism (SSCP) and dideoxy fingerprinting (ddF) were used as screening methods to detect mutated DNAs. A total of 102 individuals from 87 different families, including 10 patients (10 families) with mild-to-moderate and 92 patients (77 families) with severe hemophilia A, were analyzed by PCR-SSCP and PCR-ddF. Of the 87 independent cases, 40 revealed a single mutation in the coding regions of their factor VIII genes. These mutations include 21 with single base changes resulting in 8 nonsense and 13 missense codons, 16 with deletion or insertion of 1-11 nucleotides, and 3 with deletion of large DNA fragments. The frequency of 8 of the identified factor VIII polymorphisms or silent mutations was also determined among Chinese. The frequencies for codons 1241, 1269, and 2223 (the numbering system follows J. Gitschier et al., 1984, Nature 312: 326-330) were found to be different from those reported for other populations. As for the 47 severe cases whose mutational events were not readily detected by PCR-SSCP and PCR-ddF, the reverse transcriptase PCR method was applied. In 24 such cases analyzed, 17 were found to be of the "intron 22 mutations" as described by Naylor et al. (1992, The Lancet, 342: 1066-1067), accounting for 39% of Chinese patients with hemophilia A.

Amino Acid Sequence↗
PubMed1993

Probing the functional sites in Naja naja atra (Taiwan cobra) cardiotoxin III with monoclonal antibody.

One monoclonal antibody (mAb) against Naja naja atra cardiotoxin III was prepared by using the hybridoma technique. The cytotoxic activity of cardiotoxin III which inhibited human lymphocyte proliferation was effectively neutralized by the mAb at a molar ratio of antibody to toxin of 1:2. On the contrary, the mAb did not exert a significant inhibition on the hemolytic activity of cardiotoxin III. These results suggest that the functional site responsible for the cytotoxicity might be different from that for the hemolytic activity of cardiotoxin III.

Animals↗
PubMed1992

Chemical modification of arginine residues in alpha-bungarotoxin.

The reaction of alpha-bungarotoxin (alpha-BuTX) with 1,2-cyclohexanedione resulted in the modification of only Arg-72 but arginine at position 36 or 72, as well as both were modified by reaction of the toxin with p-hydroxyphenylglyoxal. No derivative modified at Arg-25 was obtained, indicating that this residue may be located in the interior region of alpha-BuTX molecule. Monoderivative at Arg-72 showed about 50% of the lethal toxicity and binding activity of alpha-BuTX to nicotinic acetylcholine receptor (AChR), while the activity was decreased to one-third when the invariant Arg-36 was modified, indicating that the latter residue is more closely related to the interaction of the toxin with AChR. Approx. 13% of the residual activity was observed when both arginine residues at 36 and 72 were modified. The antigenicity of alpha-BuTX was still retained essentially intact after Arg-36 or -72 was modified, whereas it decreased to 50% when both these arginine residues were modified. The present study indicates that Arg-36 and -72 in alpha-BuTX may be involved in the multipoint contact between the toxin and AChR, but neither is absolutely essential for the binding.

Amino Acids↗
PubMed1992

Defining the carbohydrate specificities of Abrus precatorius agglutinin as T (Gal beta 1----3GalNAc) greater than I/II (Gal beta 1----3/4GlcNAc).

The combining site of the nontoxic carbohydrate binding protein (Abrus precatorius agglutinin, APA) purified from the needs of Abrus precatorius (Jequirity bean), was studied by quantitative precipitin and precipitin-inhibition assays. Of 26 glycoproteins and polysaccharides tested, all, except sialic acid-containing glycoproteins and desialized ovine salivary glycoproteins, reacted strongly with the lectin, and precipitated over 70% of the lectin added, indicating that APA has a broad range of affinity and recognizes (internal) Gal beta 1----sequences of carbohydrate chains. The strong reaction with desialized porcine and rat salivary glycoproteins as well as pneumococcus type XIV polysaccharide suggests that APA has affinity for one or more of the following carbohydrate sequences: Thomsen-Friedenreich (T, Gal beta 1----3GalNAc), blood group precursor type I and/or type II (Gal beta 1----3/4GlcNAc) disaccharide determinants of complex carbohydrates. Among the oligosaccharides tested, the T structure was the best inhibitor; it was 2.4 and 3.2 times more active than type II and type I sequences, respectively. The blood group I Ma-active trisaccharide, Gal beta 1----4GlcNAc beta 1----6Gal, was about as active as the corresponding disaccharide (II). From the above results, we conclude that the size of the combining site of the A. precatorius agglutinin is probably as large as a disaccharide and most strongly complementary to the Gal beta 1----3GalNAc (T determinant) sequence. The carbohydrate specificities of this lectin will be further investigated once the related oligosaccharide structures become available.

Binding, Competitive↗
PubMed1992

Drug resistance and plasmid profile of shigellae in Taiwan.

One hundred and twenty-eight shigella strains isolated from newborn and infant human faecal specimens at Kaohsiung Medical College Hospital in Taiwan were serogrouped, serotyped and examined for drug-resistance patterns and for the presence of plasmids. Forty-seven per cent of the isolates were found to belong to the Shigella sonnei serogroup, 41% to the S. flexneri group, 9% to the S. boydii group and 3% to the S. dysenteriae group. The serotype with the greatest number of strains was S. sonnei I. (29%) followed by S. flexneri 1 (27%). Each strain was tested for resistance to 11 antimicrobial agents. Eight-eight per cent of the strains were resistant to tetracycline, 87% to chloramphenicol, 84% to streptomycin, 52% to ampicillin, 25% to nalidixic acid, 29% to kanamycin, 11% to cephalothin, 11% to neomycin, 10% to cotrimoxazole, 1% to amikacin and none to gentamicin. The most prevalent resistance pattern was ApCmSmTc (28%). Clinical isolates demonstrating multiple resistance were found to harbour a large transmissible plasmid of 45-75 MDa while isolates without multiple resistance did not. Two large virulence plasmids of 123 and 110 MDa were found in 12 strains of S. flexneri and 4 strains of S. sonnei phase I. Small plasmids of 4.5, 4.2, 3.5, 2.8, 2.5. 2.0 and 1.5 MDa were also present in all strains. These small plasmids were species specific and can be used as marker plasmids to identify species.

Acute Disease↗
PubMed1992

[Bacterial flora of the external ear canal. 2. Effect of irradiation].

A group of 34 patients with nasopharyngeal cancer was studied to observe the influence of the radiation effect on the bacterial flora of the external ear canal. The effects were observed before and after radiation therapy. The Gram-positive aerobes, especially the Staphylococcus epidermidis, were found to have decreased (57.1% to 37.7%). Though there was a slight increase of the Gram-negative aerobes (44.6% to 50.8%), it was not statistically significant. We concluded that the higher incidence of otitis externa induced by irradiation is due to the local radiation reaction, but not the shifted colonization of the potentially pathologic flora.

Adolescent↗
PubMed1991

Studies on the status of amino groups in alpha-bungarotoxin.

The positive charges of amino groups in alpha-bungarotoxin (alpha-BuTX) were neutralized by reaction with trinitrobenzene sulfonate (TNBS) and were converted into negative charges with 4-chloro-3,5-dinitrobenzoate (CDNB). Three derivatives monotrinitrophenylated (TNP-) at Lys-38, 64, or 70; three di-TNP at Lys-38 and 64, Lys-38 and 70, and Lys-64 and 70; one tri-TNP at Lys-38, 64 and 70; and one penta-TNP at Lys-38, 51, 52, 64 and 70 as well as one mono-carboxydinitrophenylated (CDNP-) at Lys-38; di-CDNP at Lys-38 and 70, and tri-CDNP at Lys-38, 64 and 70 were isolated, respectively. The epsilon-amino groups at Lys-38, 64 and 70 are the most accessible to trinitrophenylation, Lys-51 and 52 are less reactive, while the N-terminus and Lys-26 are the least reactive. Each mono-TNP and CDNP derivative showed approximately 50% residual binding activity to nicotinic acetylcholine receptor (AChR)-rich membranes isolated from Torpedo californica and 50% of the lethality of alpha-BuTX. However, the activities were progressively lost as the accumulative modifications proceeded, and led finally to the formation of almost inactive penta-TNP derivative. The antigenicity of alpha-BuTX was still retained essentially intact after one or two amino groups of lysine residues were modified, whereas tri-TNP and CDNP-derivatives modified at Lys-38, 64 and 70 lost 46 and 70% of their antigenicity, respectively. Pronounced alteration in antigenicity was observed after five amino groups were trinitrophenylated. The present study indicates that the amino groups in alpha-BuTX may participate in the multipoint contact between the toxin and AChR, but none of the individual amino groups is definitely essential for the binding.

Amino Acids↗
PubMed1990

Evaluation of urease test, gram stain, culture, and histology in the detection of Campylobacter pylori.

To evaluate the commonly available tests for detection of Campylobacter pylori infection in the human stomach, we prospectively performed endoscopy and biopsy from the antrum of the stomach in 121 consecutive patients. Four tests, including the urease test, Gram stain, culture, and the hematoxylin and eosin (H & E) stain were used to detect the presence of C. pylori. A C. pylori positive was defined by a positive culture or positive results in two of the other three tests. The sensitivity of the urease test, Gram stain, culture, and H & E stain was 95%, 95%, 71%, and 97%, respectively, and the specificity of those tests was 96%, 100%, 100%, and 73%, respectively. For diagnosis, theoretically, all four tests should be performed from the biopsy specimens. In our experience, the culture was less sensitive, and the H & E stain was less specific, while the urease test and Gram stain were more rapid and had high sensitivity and specificity in the detection of C. pylori infection.

Adolescent↗
PubMed1990

[Bacterial flora of the external ear canal. 1. Cancer patients].

The bacterial flora of the external ear canal was investigated in a group of 64 patients with head and neck cancer, to observe why otitis externa frequently occurs in cancer patients. Staphylococcus epidermidis (48.5%), Pseudomonas sp. (18.8%), and Flavobacterium sp. (16.8%) were the prominent isolates from ear samples, and Gram-negative organisms which rarely existed in normal canal, were found to be markedly increased (59.4%). Moreover, about half of all non-sterile ear canals were found to have more than one Gram-negative flora. We have concluded that cancer patients probably suffer from external otitis more frequently because of enhanced colonization by Gram-negative pathogens.

Adolescent↗
PubMed1989

Preparation and characterization of monoclonal antibody specific for alpha-bungarotoxin and localization of the epitope.

We prepared a monoclonal antibody (mAb) specific for alpha-bungarotoxin (alpha-BuTX) which can neutralize the lethal toxicity of the toxin and inhibit the binding of [3H]-alpha-BuTX to the nicotinic acetylcholine receptor. The radiolabelled toxin has a high affinity for the mAb. alpha-BuTX was digested with acid protease A and the resulting peptide fragments were isolated by reverse-phase HPLC. The epitope recognized by the mAb has been localized on the basis of competition radioimmunoassay between [3H]-alpha-BuTX and the peptide fragments of alpha-BuTX towards the antibody. The epitope specific for the mAb may be located in the second loop of alpha-BuTX, probably involving residues 34-41.

Amino Acid Sequence↗
PubMed1989

Isolation of Cryptococcus albidus var. albidus in patient with pemphigus foliaceus.

Cryptococcus albidus var. albidus was isolated from the blood of a patient with pemphigus foliaceus after steroid therapy. This organism was found in triple extract peptone medium which is used in our laboratory for blood culture to detect aerobic and anaerobic bacteria. Identification of Cryptococcus was made by the API 20C yeast carbohydrate assimilation test, together with conventional procedures. These include the demonstration of chlamydospore production, germ tube test, urease test, nitrate assimilation test and colony morphology. The patient infected with Cryptococcus albidus var albidus had a good response to oral ketoconazole therapy, then the recovered and was discharged. The isolate obtained from this case may be regarded as an etiologic agent in fungemia.

Cryptococcosis↗
PubMed1986

Herpes simplex type II encephalitis in infancy presenting with focal encephalitis.

Herpes virus was recovered from a throat swab, nasopharyngeal washings as well as from brain tissue from a six-month-old infant, who presented with fever, left focal seizures and an enhancing right frontal CT-scan lesion. Cytopathic effect (CPE) as seen with genital herpetic infection was seen, suggesting HSV-2. Immunofluorescent typing of the virus isolate confirmed HSV-2. Early IgM positivity preceding a CF and SN titer rise was observed. The patient received a course of ARA-A and recovered with a left sided hemiparesis. HSV-2 encephalitis occurs beyond the newborn period as a primary infection. In adults however HSV-2 encephalitis occurs predominantly in the immunocompromised host. HSV-1 encephalitis probably is due to reactivation of a latent herpetic infection in previous virus exposed juvenile or adult immunocompetent hosts.

Antibodies, Viral↗