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Biomedical subjects

B Lin

Publications and source records attributed to B Lin.

At least 199 records · Page 11Linked to original sources
PubMed1994

[Thumb and finger reconstruction by anastomosing the digital arteries of the toe to finger transplant].

In a series of 295 cases of toe-to-finger reconstruction, 30 cases with 40 digits were reconstructed by arterial anastomosis between digital arteries of the toe transplant and the recipient thumb or fingertoe. Among them 5 thumbs were reconstructed by the distal segment of the big toe. 11 thumbs (10 cases), 15 fingers (8 cases) and 1 case with concomitant thumb and 3 fingers were reconstructed by toe transfer. Six cases of thumb pulp defect were also reconstructed by the big toe pulp transfer. The anastomosis of digital arteries instead of dorsalis pedis artery and radial artery and saphenous vein with cephali vein to re-establish circulation is an innovation and has the advantages of simplifying the operative procedure, minimizing operative trauma, reducing operation time, attenuating patients suffering, and obtaining good appearance and function after reconstruction. Besides the operation would not be hindered by anatomical variations of the artery and would reduce blood supply disturbance of the donor foot.

Anastomosis, Surgical↗
PubMed1994

Molecular species of hepadnavirus core and envelope polypeptides in hepatocyte plasma membrane of woodchucks with acute and chronic viral hepatitis.

Hepadnaviral antigens exposed on hepatocytes serve as targets and as possible modulators of immunopathogenic reactions causing liver damage. To identify molecular species of viral proteins at the liver cell surface and the relationship between their expression and the persistence and severity of virus-induced liver injury, we examined woodchuck hepatitis virus core and envelope polypeptides in host hepatocyte plasma membranes from acute and chronic hepatitis. Western blot analysis revealed that two virus core polypeptides with a molecular mass of 22 kD and 43 kD occur in the membranes of infected animals. The molecular profiles and the membrane levels of the core antigen were not related to the duration or histological severity of liver damage. In contrast, quantities of the virus surface antigen were significantly greater in hepatocyte membranes of animals with chronic hepatitis. The envelope preS1, preS2 and S polypeptides, with or without molecular mass equivalents in the subviral surface antigen particles and virions, were detected in all infected membranes, although the preS2 polypeptides were always dominant. Our findings indicate that hepadnavirus core and envelope polypeptides are integral constituents of hepatocyte membranes in the course of hepatitis. They demonstrate that the accumulation of viral envelope proteins, predominantly the S-domain sequences, in hepatocyte membranes is a prominent characteristic of chronic hepatitis. This event might contribute to promotion of development and maintenance of hepadnavirus-related chronic liver disease.

Acute Disease↗
PubMed1993

Identification of an Alu retrotransposition event in close proximity to a strong candidate gene for Huntington's disease.

Huntington's disease (HD) is a late-onset autosomal dominant neuropsychiatric disorder presenting in mid-adult life with personality disturbance and involuntary movements, cognitive and affective disturbance, and inexorable progression to death. The underlying genetic defect has been mapped to chromosomal band 4p16.3 (refs 2, 3). Analysis of specific recombination events in some families with HD has further refined the location of the HD defect to a 2.2 megabase DNA interval. Using a direct complementary DNA selection strategy we have identified at least seven transcriptional units within the minimal region believed to contain the HD gene. Screening with one of the cDNA clones identified an Alu insertion in genomic DNA from two persons with HD which showed complete cosegregation with the disease in these families but was not found in 1,000 control chromosomes. Two genes including the previously identified alpha-adducin gene and another that encodes for a 12-kilobase transcript, map in close proximity to the Alu insertion site. The 12-kilobase transcript should be regarded as a strong candidate for the HD gene.

Base Sequence↗
PubMed1993

Acquired amegakaryocytic thrombocytopenic purpura with a Philadelphia chromosome.

A 30-year-old Chinese man with acquired amegakaryocytic thrombocytopenic purpura (AATP) and a Ph chromosome is reported. At presentation, he had severe thrombocytopenia resulting in epistaxis, gingival bleeding, and ecchymoses, while other hematologic values were within the normal range. Bone marrow aspiration showed no megakaryocytes, with a normal appearance of erythroblastic and granulopoietic series. He failed to respond to prednisone treatment, and underwent a progress from isolated thrombocytopenia to full pancytopenia. At last he died of spontaneous intracranial hemorrhage. An in vitro culture for granulocyte-macrophage precursors showed very few colonies. Karyotypic analysis revealed a standard Ph chromosome translocation, t(9;22)(q34;q11), in the majority of bone marrow cells. Southern blot analysis using a 3' bcr-HE probe didn't detect a rearrangement within the bcr DNA sequence. This patient, in fact, was a myelodysplastic disorder, initially presenting as AATP. The diagnosis of chronic myelogenous leukemia was excluded on the basis of clinical and hematologic findings. The heterogeneity of Ph chromosome in myelodysplastic syndrome is discussed.

Adult↗
PubMed1993

Vaccination of bovines against Schistosomiasis japonica with cryopreserved-irradiated and freeze-thaw schistosomula.

Four laboratory tests and one field trial with cryopreserved irradiated (CI) schistosomula vaccine and a freeze-thaw (F/T) vaccine against bovine Schistosomiasis japonica were carried out in 1979 and 1980 with the following results: (1) Single intradermal vaccination in buffalo calves each with 10,000 20 krad CI Schistosomula plus 1 ml BCG gave 62% worm reduction (P < 0.05). Using the same protocol 55% worm reduction (P < 0.01) was obtained in cattle. (2) Buffalo calves immunized twice, at a 1.5 month interval, with 10,000 and 20,000 CI schistosomula, respectively, resulted in a worm reduction 65%. (3) In a preliminary field trial with 10,000 CI schistosomula plus 1 ml BCG resulted in a worm reduction of 53% in buffalo calves. (4) Intradermal vaccination of 30,000 F/T schistosomula with 1 ml BCG was also tried in cattle and revealed a worm reduction of 57% but increasing the number of vaccinations did not improve the protective effect. (5) Evidence regarding the effects of immunization with CI vaccine in buffaloes and F/T vaccine in cattle, on the number of eggs and miracidia and that of female worms themselves was obtained. (6) Immune responses, cellular and humoral, elicited in buffaloes vaccinated with CI schistosomula were detected by means of Lymphocyte Transformation Assay and Enzyme Linked Immunosorbent Assay.

Animals↗
PubMed1993

MK-801 (dizocilpine) protects the brain from repeated normothermic global ischemic insults in the rat.

We investigated the neuroprotective potential of MK-801 (dizocilpine), a noncompetitive N-methyl-D-aspartate (NMDA) antagonist, in the setting of three 5-min periods of global cerebral ischemia separated by 1-h intervals in halothane-anesthetized rats. Each ischemic insult was produced by bilateral carotid artery occlusions plus hypotension (50 mm Hg). Brain temperature was maintained at normothermic levels (36.5-37.0 degrees C) throughout the experiment. MK-801 (3 mg/kg) (n = 6) or saline (n = 6) was injected intraperitoneally 45 min following the end of the first ischemic insult. Following 7-day survival, quantitative neuronal counts of perfusion-fixed brains revealed severe ischemic damage in hippocampal CA1 area, neocortex, ventrolateral thalamus, and striatum of untreated rats. By contrast, significant protection was observed in MK-801-treated rats. In area CA1 of the hippocampus, numbers of normal neurons were increased 11- to 14-fold by MK-801 treatment (p < 0.01). The ventrolateral thalamus of MK-801-treated rats showed almost complete histologic protection, and neocortical damage was reduced by 71% (p < 0.01). The degree of MK-801 protection of striatal neurons was less complete than that seen in other vulnerable structures, amounting to 63% for central striatum (p = 0.02, Mann-Whitney U test) and 48% in the dorsolateral striatum (NS). A repeated-measures analysis of variance demonstrated a highly significant overall protective effect of MK-801 treatment (F1,10 = 37.2, p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The relationship between trinucleotide (CAG) repeat length and clinical features of Huntington's disease.

Huntington's disease (HD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene. We have assessed 360 HD individuals from 259 unrelated families and found a highly significant correlation (r = 0.70, p = 10(-7)) between the age of onset and the repeat length, which accounts for approximately 50% of the variation in the age of onset. Significant associations were also found between repeat length and age of death and onset of other clinical features. Sib pair and parent-child analysis revealed that the CAG repeat demonstrates only mild instability. Affected HD siblings had significant correlations for trinucleotide expansion (r = 0.66, p < 0.001) which was not apparent for affected parent-child pairs.

Adolescent↗
PubMed1993

Differential 3' polyadenylation of the Huntington disease gene results in two mRNA species with variable tissue expression.

Recently a novel gene containing a CAG trinucleotide repeat that is expanded on HD chromosomes has been identified(1). This gene was shown to detect a single transcript of 10-11 kb by RNA hybridization. We have however, previously identified three cDNAs which are part of the same gene that have been shown to detect two distinct transcripts of 10 kb and one that is significantly larger(2,3). These different mRNA species could be due to use of alternate transcription start sites, alternate splicing or selection of different polyadenylation sites. We have identified cDNA clones spanning the HD gene including two (HD12 and HD14) that share identical protein coding sequences but differ in size and sequence of their 3' untranslated region. HD14 has 3,360 base pairs of additional sequence distal to the previously published 3' end (1). RNA hybridization has revealed that the larger 13.7 kb fragment is the predominant transcript in human brain. cDNA fragments unique to HD14 detected only the larger transcript. Sequence analysis identified two different putative polyadenylation sequences at position 10,326 and 13,645 of the HD14 cDNA. These findings indicate that the two observed mRNA species originate from a single gene and that differential polyadenylation leads to transcripts of different size. The relative increased abundance of the larger transcript in human brain may provide some insights into the mechanism by which a widely expressed gene may exert tissue specific effects.

Base Sequence↗
PubMed1993

A transcription map of the region containing the Huntington disease gene.

A transcription map of the Huntington disease gene region was generated by a direct cDNA selection strategy using genomic DNA from the 4p16.3 region surrounding the D4S95 and D4S127 loci. A total of 58 cDNA fragments were obtained from cDNAs derived from fetal brain, frontal cortex, liver and bone marrow following hybridization to overlapping YACs from this region. These cDNA clones were aligned into transcription units by hybridization to specific mRNAs, by sequence overlap and by physical mapping onto overlapping YAC clones. Nine separate transcription units spanning approximately one megabase were detected by RNA hybridization. They represent a minimum number of genes in this region and do not include those genes expressed specifically in tissues not used for the hybridization. The transcription map that is provided by the cDNA segments will lead to the generation of a detailed gene map of this region.

Base Sequence↗
PubMed1993

Group B streptococcal neuraminidase is actually a hyaluronidase.

The extracellular group B streptococcal enzyme described in numerous reports as a neuraminidase is really a hyaluronidase. Over the past 25 years, the enzyme was routinely assayed with bovine submaxillary mucin as the substrate and by the thiobarbituric acid procedure to measure released sialic acid. Characterization of the actual compound released by the enzyme revealed it to be an alpha,beta-unsaturated derivative of hyalobiuronic acid that was derived from hyaluronic acid contaminating the mucin preparation. Previous reports describing an association of elevated levels of extracellular neuraminidase with virulent strains of group B streptococci must be reevaluated with the recognition that the enzyme is really a hyaluronidase.

Amino Acid Sequence↗
PubMed1992

Specific chromosomal translocations and therapy-related leukemia induced by bimolane therapy for psoriasis.

This paper reports for the first time results of cytogenetic studies on 14 consecutive secondary acute non-lymphocytic leukemia (S-ANLL) induced by bimolane therapy. They included 10 males and 4 females with ages ranging from 17 to 54 years. They had all suffered from psoriasis and received bimolane treatment before the occurrence of their leukemia. The total dose of bimolane ranged from 40 to 400 g (mean dose 194 g). The interval between the initiation of bimolane therapy and the diagnosis of leukemia was 12-96 months (median 30 months). A preleukemic phase was only found in one case. No dysplastic features in the hemopoietic series were seen in any patient. Chromosome analysis of bone marrow cells using banding techniques revealed clonal karyotypic abnormalities in all cases: t(15;17) in 8 cases of M3, of which 75% had extra abnormalities, t(8;21) in 4 cases of M2, del(7q) only in one case of M4 and one case of M5. After antileukemic therapy, complete remission was obtained in 10 out of 12 cases with specific translocations and one out of 2 cases with 7q-anomaly, respectively. The former survived 4-58 months (median 12 months), while the latter 1 and 9 months, respectively. This study indicates that: (1) bimolane is a causative factor of leukemia in this series; (2) the leukemia in our series is therapy-related leukemia (TRL) rather than de novo ANLL; (3) there exists, in fact, a new subgroup of TRL characterized by specific rearrangements, whose clinical, hematological and prognostic features and pathogenetic mechanism may be different from classical TRL characterized by chromosome abnormalities involving absence or deletion of parts of chromosome 5 and/or 7.

Adolescent↗
PubMed1992

Geographical clusters of dengue virus type 2 isolates based on analysis of infected cell RNA by the chemical cleavage at mismatch method.

Genetic variation in 12 strains of dengue virus type 2, isolated from several epidemic areas in different years, was studied by chemical cleavage at mismatched cytosine in DNA:RNA heteroduplexes. End-labelled cDNA probes derived from the E and NS2A genes of the New Guinea C strain were hybridized to total RNA extracted from cells infected by individual isolates. Following modification of mismatched cytosine by hydroxylamine and nucleic acid strand cleavage by piperidine, the resulting fragments of radiolabelled probe were analysed by electrophoresis and autoradiography. The patterns of bands generated corresponded to the geographical groupings of the isolates. Thus this method is suitable in epidemiological studies for rapidly surveying a large number of isolates for genetic variation in a particular gene of interest.

Base Composition↗
PubMed1992

Differing neurochemical and morphological sequelae of global ischemia: comparison of single- and multiple-insult paradigms.

The purpose of this investigation was to investigate pathomechanisms responsible for the deleterious effects of repeated episodes of brief forebrain ischemia. Halothane-anesthetized male Wistar rats were subjected to either (a) a single 15-min period or (b) three 5-min periods (separated by 1 h) of global forebrain ischemia by bilateral carotid artery occlusions plus hypotension (50 mm Hg), followed by various periods of recirculation. Brain temperature was normothermic throughout. In one series of rats, extracellular levels of glutamate, glycine, and gamma-aminobutyric acid (GABA) were measured in the dorsolateral striatum (n = 6-8 per group) and lateral thalamus (n = 4-6 per group) by microdialysis and HPLC before and during ischemia and during 3-5 h of recirculation. In a parallel series of rats (n = 6 per group), ischemic cell change was quantified at 2 (dark neurons), 24, or 72 h following either single or multiple ischemic insults. A single 15-min ischemic period led to massive glutamate release (13-fold increase; p = 0.001), which returned to normal by 20-30 min of recirculation and remained normal thereafter. By contrast, in rats with three 5-min periods of ischemia, the glutamate level rise with each repeated insult (four- to 4.5-fold; p < or = 0.02) was smaller than that observed during the single 15-min insult, but a late sustained rise (five- to six-fold; p < 0.05) occurred at 2-3 h of recirculation. Brief ischemia-induced elevations of glycine and GABA levels were detected in both the single- and multiple-insult groups, with normalization during recirculation. In contrast, the excitotoxic index, a composite measure of neurotransmitter release ([glutamate] x [glycine]/[GABA]), differed markedly following single versus multiple insults (p = 0.002 by repeated-measures analysis of variance) and increased by seven- to 12-fold (p < 0.05) at 1-3 h following the third insult. The total amount of glutamate released was 3.3-fold higher in the multiple-insult than in the single-insult group (p < 0.02). At 2 h of recirculation, histopathological analysis of dorsolateral striatum showed a significantly greater frequency of dark neurons in the multiple- than in the single-insult group (p < 0.05 by analysis of variance). In the thalamus, a higher frequency of ischemic neurons was seen in the multiple-than in the single-insult group at all intervals studied. Thus, in rats with multiple ischemic insults, accelerated ischemic damage was found in the striatum, and severe ischemic injury was documented in the thalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗
PubMed1992

[Effect of oxytocin and cholecystokinin octapeptide (CCK-8) on electroacupuncture (EA) analgesia].

The effect of oxytocin (OT) and cholecystokinin octapeptide (CCK-8) on EA analgesia was studied in rats. The increase of 20.8-39.8% and 9.0-45.0% in pain threshold was observed respectively when ICV of CCK-8 or naloxone was combined with EA, these increases were lower than that in saline-EA group significantly, while the simultaneous ICV of OT and CCK-8 or OT and naloxone in combination with EA produced the increase of 76.2-116.6% and 41.8-104.5% in pain threshold separately. These results showed that only a small part in the role of OT enhancing EA analgesia was blocked by CCK-8 and naloxone. The data suggest that the role of OT in EA was not entirely dependent upon the endogenous opiate peptides.

Acupuncture Analgesia↗
PubMed1992

[Effect of Asu-AVT on electroacupuncture (EA) analgesia].

The Asu-AVT (1,6-aminosuberic acid -8-arginine-vasotocin) in an analogue of 8-arginine-vasotocin (AVT) which is one of pineal hormones. The effect of Asu-AVT on the pain threshold and EA analgesia was studied in rats. An increase of 16.2-41.5% in pain threshold was observed within 70 min. after ivc of Asu-AVT (75ng), while the Asu-AVT injection in combination with EA produced a significant increase of 164.6-309.1% in pain threshold, which was much higher than that in the saline-EA group (p < 0.05-0.01). The effect of Atu-AVT is analogous to that of oxytocin and arginine-vasopressin. The data indicate ivc of ASu-AVT not only elevates the pain threshold, but also enhances the EA analgesia. These results suggest that the pineal hormone, AVT may play a role in the EA analgesia.

Acupuncture Analgesia↗